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LiU-ITN-TEK-A-15/003-SE Isolated WiFi Environments Jacob Carlsson 2015-02-04 Department of Science and Technology Linköping University SE-601 74 Norrköping , Sw eden Institutionen för teknik och naturvetenskap Linköpings universitet 601 74 Norrköping LiU-ITN-TEK-A-15/003-SE Isolated WiFi Environments Examensarbete utfört i Elektroteknik vid Tekniska högskolan vid Linköpings universitet Jacob Carlsson Handledare Qin-Zhong Ye Examinator Shaofang Gong Norrköping 2015-02-04 Upphovsrätt Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under en längre tid från publiceringsdatum under förutsättning att inga extraordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning av dokumentet kräver upphovsmannens medgivande. För att garantera äktheten, säkerheten och tillgängligheten finns det lösningar av teknisk och administrativ art. Upphovsmannens ideella rätt innefattar rätt att bli nämnd som upphovsman i den omfattning som god sed kräver vid användning av dokumentet på ovan beskrivna sätt samt skydd mot att dokumentet ändras eller presenteras i sådan form eller i sådant sammanhang som är kränkande för upphovsmannens litterära eller konstnärliga anseende eller egenart. För ytterligare information om Linköping University Electronic Press se förlagets hemsida http://www.ep.liu.se/ Copyright The publishers will keep this document online on the Internet - or its possible replacement - for a considerable time from the date of publication barring exceptional circumstances. The online availability of the document implies a permanent permission for anyone to read, to download, to print out single copies for your own use and to use it unchanged for any non-commercial research and educational purpose. Subsequent transfers of copyright cannot revoke this permission. All other uses of the document are conditional on the consent of the copyright owner. The publisher has taken technical and administrative measures to assure authenticity, security and accessibility. According to intellectual property law the author has the right to be mentioned when his/her work is accessed as described above and to be protected against infringement. For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its WWW home page: http://www.ep.liu.se/ © Jacob Carlsson Abstract WiFi is becoming common in households and digital devices needs to support it. At the same time the devices are getting smaller and the Ethernet port may seem superfluous. When testing these devices the test environment needs to be able to provide WiFi connectivity. The tests may be focused on testing WiFi but it could also be the only network connectivity and thus needs to be very reliable. With a large number of devices in a small physical area a normal WiFi setup would have a density of devices that is too high for today’s1 WiFi standards. A combination of wired physical medium and physical isolation was considered. 1 The current standards considered in this report is 802.11ac, but the one currently used in households are still 802.11n to a large extent. 1 Acknowledgments I want to thank ARRIS for giving me the opportunity to write this master thesis and for investing in equipment when necessary, something that would not have been possible without financial support. A big thank you to Jonna Bengtsson at ARRIS for all the help and support you have given me. There has been hundreds of questions about KATT, paperwork, contacting the right people, feedback about reports and written text. You have helped me focusing on the right things to speed up my work flow. I want to thank Jonas Blick, Magnus Ekhall, Carl Ljungström and Krister Berglund at ARRIS for technical discussions and guidance and Johan Rodin at ARRIS for all the help with network related questions and problems. I want to thank Shaofang Gong and Qin-Zhong Ye, my examiner and supervisor at Linköping University for help with practical concerns and paperwork as well as technical questions. I would also like to thank my family Rebecka, Algot and Tage for constantly encouraging me to work hard and for all the great smiles in the mornings. Linköping, January 2015 Jacob Carlsson 3 Contents Notation 7 1 Introduction 1.1 Objective . . . . . . . 1.2 Scope of work . . . . 1.3 Method . . . . . . . . 1.4 Discussion of sources 1.5 Outline . . . . . . . . 1.6 ARRIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2 2 3 4 4 2 Background 2.1 Environment . . . . . 2.2 Connected devices . . 2.3 WiFi . . . . . . . . . . 2.4 Isolation . . . . . . . 2.5 Considered methods 2.6 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5 7 7 12 13 14 3 Wired setup 3.1 Components . . . . . . . . . . . . 3.2 Attenuation between components 3.3 Throughput . . . . . . . . . . . . 3.4 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 20 21 22 22 4 Encapsulation 4.1 Faraday cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 RF-shielding enclosures . . . . . . . . . . . . . . . . . . . . . . . . . 23 23 25 5 Result 5.1 Wired setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 27 34 6 Discussion 39 5 Contents 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Wired setup . . . WiFi technology . Throughput . . . Isolation . . . . . Reliability . . . . Measurements . . Adoption in KATT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 39 39 40 41 41 41 7 Conclusion 7.1 Wired setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Final solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 43 44 44 8 Future Work 8.1 Single antenna wired setup . . . . . . . . . . . . . . . . . . . . . . . 8.2 Wireless setup in RF-shielding enclosure . . . . . . . . . . . . . . . 8.3 More set-top boxes per AP . . . . . . . . . . . . . . . . . . . . . . . 45 45 45 46 Bibliography 47 A Considered methods 51 B JRE RF-shielding enclosures datasheets 63 C Mini Circuits datasheets 67 Notation Nomenclature Word Description client A device that is currently connected to a network (and is not the Access point) Decibel is a logarithmic unit that express a ratio between two values. Often used in electronics Decibel-milliwats is a power ratio in decibels (dB) of the power divided by 1 mW. A convenient measure of absolute power Wireless Fidelity is a wireless network implementing the 802.11 standard dB dBm WiFi Abbrevations Abbrevation SMA RF RSSI KATT AP STB TCP UDP Description SubMiniature version A is a connector for RF cables Radio Frequency is a rate of oscillation in the range 3 kHz –300 GHz Received Signal Strength Indicator is an indication of the signal strength of different networks KreaTV Automated Test Tools is a framework for automated tests of KreaTV set-top boxes at ARRIS Access Point Set-top box Transmission Control Protocol provides a connection between hosts that are reliable, ordered and errorchecked User Datagram Protocol is a simple protocol that does not guarantee delivery or the received order of packets 7 1 Introduction Providing WiFi connectivity to a large number of devices with high throughput is difficult. When in a small physical space the networks will interfere with each other and the throughput will be constrained. A solution to this problem has been considered where the networks have been isolated from each other and therefore interference is minimized. The solution is to create a wired network where the antenna connectors have been interconnected, this of course means that the network is not wireless any more. By connecting the devices at the antenna connectors they will work as normal, from the single device’s perspective the network appears as wireless. The devices will be able to use wireless network hardware and software with high throughput in a very limited physical space. RF-shielding enclosures has been used to further isolate the network, these are specialized enclosures that attenuates radio frequency signals. By encapsulating the network, signals will be attenuated and the entire network will be isolated. The RF-shielding enclosures also attenuates signals from other networks which further isolates the enclosed network. 1.1 Objective The objective of this work is to: • Provide WiFi connectivity to a large number of devices • Provide high throughput • Isolate small networks that will use WiFi but not affect or be affected by other networks • Fit in a small physical space 1 2 1 Introduction 1.2 Scope of work This work is focused on providing network connectivity using the WiFi standard 802.11ac. The solution will be using of the shelf components to the highest extent to make scaling easier and less time consuming. Using of the shelf components that are tested by the manufacturer will introduce less errors than custom made components. This is a master thesis work of 30 ECTS 1 and is limited to 20 weeks of work. Out of scope Security is out of scope for this work and will not be considered. With that said, WiFi has encryption algorithms that will add data overhead and decrease the throughput. All tests with WiFi will use WPA2-Personal encryption (Wi-Fi Protected Access 2). 1.3 Method This work has been done with literature studies, especially in WiFi technology, laboratory work and observations. With literature studies I proposed some possible solutions that were discussed with ARRIS and we agreed to further investigate two of these. The first is to interconnect all devices antenna connectors with wires to isolate them from other networks, this is described in chapter 3. To further attenuate the signals that are sent out and signals from other networks, different types of encapsulation are described in chapter 4. All the proposed solutions can be seen in appendix A. Literature study To get understanding and ideas a literature study was conducted especially in WiFi and high density networks. WiFi WiFi is the technology used in this work and therefore this was studied in depth. The main focus was the physical layer and how it is used. The limiting factor in this work is that when devices are connected to a network, they will remain silent if there is communication on the same channel. This means that the network channel can not be reused in the same physical space. Because all channels are already occupied by other networks it is not possible to use multiple channels to get the desired throughput to a large number of clients. The channel needs to be reused and most desirable the network should be isolated from other networks. The problem is to solve this with a good solution. 1 European Credit Transfer and Accumulation System is a standard for comparing higher education students results in Europe. One year corresponds to 60 ECTS and 40 weeks 1.4 Discussion of sources 3 Previous work and ideas I did not find any previous work in this exact area but I found inspiration from conferences where they have a very high density of devices (large amount of devices per area). At conferences the number of devices is very large and the space is often limited. A big difference between conferences and this work is that I am able to modify all equipment and I have more information about all the devices. At conferences the wireless networks needs to support older versions of the WiFi standard and the coverage have to be good. Microsoft research have designed a wireless data center for 60 GHz WiFi [10]. In their work they use directed antennas to focus the wireless signals to different parts of the system. The main difference in this work is that they use 60 GHz waves as technology, which has a much higher attenuation with distance, which would have been good in this case but something that I was not able to do with 5 GHz waves. The attenuation with distance for 5 GHz can be seen in figure 2.1. The hardest part of the literature study was to find previous work on this subject and to apply that to the problems in this work. Because this is an in-house solution for larger companies it may not be something that they make publicly accessible. 1.4 Discussion of sources These are the most influencing resources for this work. They are specifications, books and research done in the WiFi area. WiFi Below is the most influencing WiFi sources used in this work. Matthew Gast Matthew has written the books 802.11ac: A Survival Guide and 802.11 Wireless Networks: The Definitive Guide which goes through WiFi. Matthew has served as the chair of the security groups at the Wi-Fi Alliance. The books are sold at oreally.com and has great reviews. 802.11ac WiFi standard The standard 802.11ac is the latest standard for WiFi by the Wi-Fi Alliance. This is a standard that is used by the manufacturers and the Wi-Fi alliance are the organization that certifies devices. Research Sources from research are listed below. 4 1 Introduction Microsoft research The research project “On the Feasibility of Completely Wireless Datacenters” was conducted at Microsoft research by Cornell University and I think they have the right knowledge and their reputation to account for when publishing something like this. The report contains sources and authors with contact information. 1.5 Outline 1 Introduction Describes problem and motivation 2 Background Background knowledge about WiFi and the environment 3 Wired setup Using wires instead of antennas 4 Encapsulation Isolating the network from other networks 5 Result Result of all measurements and the setup 6 Discussion Discussion of this work 7 Conclusion Conclusions about this work 8 Future Work What could be done to extend this work Appendix Appendix with proposed solutions and datasheets 1.6 ARRIS ARRIS innovates video and IP-technology for entertainment and communication for people around the world. In Linköping both hardware and software are developed. KreaTV Automated Test Tools (KATT) is a great way to continuously test and improve the set-top boxes. 2 Background This chapter provides background theory about wireless networks, the WiFi standard used in this work and other important parts. It also includes a description of the environment and the difficulties with it. 2.1 Environment The environment for this work is a medium sized room, about 75 m2 . Because of the limited size, a wireless network layout would not be able to provide the required throughput. Figure 2.1 shows the received power from 3 signals sent with different power in dBm1 . The attenuation is high but a signal power of -62 dBm will still be received by a WiFi access point, this means that the range of a signal sent with 20 dBm2 is interfering with another network at 100 meters [9]. Even at longer distances that signal is still contributing to noise. This long distance means that at 100 meters apart, it will still not be possible to reuse the same channel, more about this in the WiFi section 2.3. The room is located inside company premises and the network will therefore interfere with and receive noise from other networks. It will not be possible to use all available channels and this will limit the throughput. There are a large number of clients that needs to access the network, all with high throughput. Because of the physical size of the room the distribution of devices is limited. Pwatt 1 A signal power of 20 dBm is 0.1 Watts. P dBm = 10 ∗ log10 ( 1 mW ). 2 20 dBm is in the range of a normal output from an access point. The AP used in this work is configurable to have an output power of 10 - 20 dBm 5 2 6 0 RSSI of received signal at 5 GHz in air 10 20 Background 20 dBm 5 dBm 0 dBm RSSI [dBm] 30 40 50 60 70 80 900 20 40 60 Distance [m] 80 100 Figure 2.1: Signal attenuation in free space. The graph shows theoretical values of a 20 dBm signal, a 5 dBm signal and a 0 dBm signal transmitted and the attenuation with distance from the transmission point. 2.2 Connected devices 7 Figure 2.2: The Wi-Fi CERTIFIED™ logo. Only products that pass the Wi-Fi Alliance® testing can bear the logo [4]. The Wi-Fi CERTIFIED™ logo is a registered trademark of Wi-Fi Alliance®. 2.2 Connected devices The goal is to connect many devices, hereby called clients or devices to a WiFi network. These clients could be different types of devices but in this work they are typically ARRIS VIP1113W set-top boxes, more information about these devices can be seen in section Set-top box on page 11. 2.3 WiFi WiFi is a wireless network that is certified by the WiFi Alliance and based on the IEEE 802.11 standards [3]. Figure 2.2 shows the Wi-Fi certified logo that only products that pass the Wi-Fi Alliance® certification process can bear. The original version of IEEE 802.11 was released in 1997 and the current version 2014 is IEEE 802.11ac2013 [9, 2]. WiFi currently uses frequencies of 2.4 GHz and 5 GHz. The initial products were limited to 2 Mbit/s and by 1999 the 802.11b standard had an operating speed of up to 11 Mbit/s while the 802.11a and 802.11n standard operated in the 5 GHz band and had a speed of up to 54 Mbit/s [8, 9, p. 9]. The new standard 802.11ac uses the 5 GHz band and promises a data rate of over 1 Gbit/s3 [2, 11]. The 802.11ac standard uses only the 5 GHz band but is backwards compatible with 802.11a/n operating in the 5 GHz band [12, 11]. In this work the standard 802.11ac is used because of the high throughput. The set-top boxes supports the 802.11ac standard and therefore it is not necessary to consider an older standard in this work. The IEEE 802 standard is focused on the two lowest layers in the OSI model (Open Systems Interconnection), the media access control (MAC) layer and physical (PHY) layer, seen in figure 2.3 [8]. 802.11 could be described as “just another link layer for 802.2” [8]. The standard 802.11 Accessing the medium The 802.11 standard uses a distributed access scheme where all devices are allowed to access the medium (in the WiFi case this means 3 1 Gbit/s was achieved with 802.11ac in 2013 [9] 2 8 Background Application Presentation Session Transport Network Data link Physical Figure 2.3: The OSI model with the two lowest layers highlighted using the air) [8, p. 24]. 802.11 uses the algorithm Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) which is build upon the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) algorithm used in previous IEEE 802 standards, but instead of detecting collisions they are avoided [8, p. 24]. The algorithm senses if the medium is available, if not it waits random time (in a predefined interval of microseconds). This is used because collisions waste more transmission capacity than avoiding them [8, p. 24]. When WiFi senses the medium a threshold of -82 dBm is used for detecting signals, if the received signal power is larger than this the device will wait [9]. There are 3 different transmissions possible in 802.11, these are Unicast to a specific device, Multicast to multiple devices and Broadcast to all devices. Unicast allows for two additional packets: Request to Send (RTS) and Clear to Send (CTS). The sender sends a RTS and the responder sends a CTS, this tells all stations that hear the CTS to be quiet for the specified time. These packets are sent to get a duration in which the medium is only available to the device that sent the RTS packet. This makes it possible to send data without collisions. This is especially useful when there are hidden nodes in the network that will not receive the packets sent from the sender but only those sent from the receiver. An example of a hidden node (client) can be seen in figure 2.4. In this example A wants to send a packet to B but because C is hidden from A it will not receive any packets send from A. This may result in collisions at B if both A and C is sending at the same time. To avoid this A is sending a Request to Send (RTS) that will only be received by B. B will then send a Clear to Send (CTS) that both A and C will receive. C will then wait for the specified time and A is able to send data to B without collisions 2.3 WiFi A 9 B C A (a) A wants to send to B but C are unable to receive this communication and thus may send data at the same time as A, resulting in collisions at B. B C A (b) B – the receiver – are able to receive packets and send packets to both A and C. B C (c) C is able to communicate with B but A is hidden from C and will not receive any packets that are sent from C Figure 2.4: These images shows hidden nodes, that are a contributing to collisions. 1 2 3 20 MHz 4 5 6 7 8 9 10 11 12 13 14 5 MHz Figure 2.5: 802.11n channels in the 2.4 GHz band, channels 1, 6, 11 and 14 can be used without overlap but channel 14 is not allowed everywhere. Redrawn from 2.4 GHz Wi-Fi channels (802.11b,g WLAN) by Michael Gauthier (CC BY-SA 3.0) for the 802.11n standard. Channels WiFi uses a range of frequencies that are divided into multiple channels with fixed bandwidth. Channels are used to make it easier for multiple networks to share the available bandwidth. The 802.11ac standard, which uses the 5 GHz band, introduces wider channel widths which enables higher throughput [9]. 2.4 GHz and 802.11n At the 2.4 GHz band in the 802.11n standard a channel bandwidth of 20 MHz is used but has overlaps as seen in figure 2.5. Channels 1, 6 and 11 can be used which would provide a channel layout without overlap. Overlapping channels introduces interference and should be avoided. 2 10 Background 802.11ac channels in Europe 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140 20 MHz 38 46 54 62 102 110 118 126 134 40 MHz 58 42 106 122 138 80 MHz 50 114 160 MHz 5.2 5.3 5.4 5.5 5.6 5.7 GHz Figure 2.6: Channels for the 802.11ac standard in Europe. The integers above each subplot are the IEEE channel number. 5 GHz and 802.11ac The channels in the 5 GHz band are not that easily defined because of regulations. Because the frequency spectrum are also used for other technologies than WiFi, countries has approved use of different channels. The european standard EN 301 893 defines the Radio LAN (RLAN) bands to 5 150 MHz – 5 350 MHz and 5 470 MHz – 5 725 MHz [6]. The channels have bandwidths of 20 MHz but the 802.11ac standard also includes 40 MHz, 80 MHz and 160 MHz channel bandwidths in the 5 GHz band [9]. The allowed channels in Europe can be seen in figure 2.6. Access point An access point (AP) bridges the wired network and the wireless clients [8, p. 16]. A client can only be connected to a single access point at any time. The access point is the center of the network and all traffic will go through it. In this work the access point ARRIS VAP3400 was used, the specification can 2.3 WiFi 11 Table 2.1: Specification for the ARRIS VAP3400 access point Specification Model name WiFi version WiFi antennas Antenna usage DHCP WiFi certified Value Arris VAP3400 dual band 802.11n/ac 4 MIMO no yes Table 2.2: Specification for the ARRIS VIP1113W set-top box Specification Model name WiFi version WiFi antennas Ethernet ports Antenna usage HDMI ports USB ports Value VIP1113W dual band 802.11n/ac 2 1 MIMOa 1 1 a Multiple Input Multiple Output enables very high throughput between devices with multiple antennas be seen in table 2.1. Set-top box A set-top box is an internet enabled media device that is able to stream e.g. TV and movies. The set-top boxes used in this work are two ARRIS VIP1113W. These are small devices with an ethernet port and a WiFi chip with two antennas. The specification can be seen in table 2.2. Noise and interference For WiFi to work the signal needs to be good, this means that the Signal-to-Noise ratio (SNR) needs to be high. SNR is a measure of the power of the signal compared to the power of noise, P SN R = Psignal . If the signal power is strong and the noise is weak there will be a noise very small error in the conversion to data but if this ratio is low there may be a high rate of errors or even impossible to convert the signal to data. 12 2 Background Figure 2.7: A Faraday cage in operation: the women inside are protected from the electric arc by the cage. Photograph taken at the Palais de la Découverte in Paris (Discovery Palace) (CC BY-SA 3.0). 2.4 Isolation To isolate a WiFi network the radio waves of other networks should not be recognizable or add noise to the current network. The current network’s radio waves should not be recognized or add noise to other networks. In this work I have focused on faraday cages and RF-shielding enclosures to isolate the network. These work by compensating the electromagnetic field created by the network with an internal reverse electromagnetic field that will cancel out the surrounding field. In figure 2.7 is a faraday cage in operation, the woman does not get electrocuted because the cage is canceling out the applied electric field. RF-shielding enclosure The RF-shielding enclosure is a product specifically developed to cancel out RF-fields from electrical equipment for testing purposes. As well as a surrounding faraday cage it also has an absorbing material inside that will cancel out reflections and standing waves. An RF-shielding enclosure also has filtered Input and Output (I/O) connectors, this can be seen in figure 2.8b. Two images of a small RF-shielding enclosure are shown in figure 2.8. 2.5 Considered methods (a) The inside of a small RF-shielding enclosure 13 (b) The outside of a small RFshielding enclosure with the connectors shown Figure 2.8: A small RF-shielding enclosure with nothing connected. The enclosure is only accessible via the RF filtered connectors shown in subfigure (b). 2.5 Considered methods Multiple methods were considered where isolation was the main takeaway to solve the problems in this work. All the considered methods are located in appendix A while this section describes the most important ones. Directed antennas are used to focus the signal in one direction and could be used to only send to a subset of all devices. This results in a separation in space and isolation between different networks. The directed antennas are only focusing in a specific direction but the distance that the signals could travel will not be shorter. As all the devices would have to use directed antennas the cost and complexity of this system is high. Using wires to connect the antennas would make the network wired and no longer wireless but as WiFi technology is still used the devices would not notice. The wires would shield the network from other networks resulting in isolation from other networks. Encapsulating the network with a faraday cage would provide isolation from other networks and make a system that is very easy to understand as you will see the boundaries between different networks clearly. By using different channels the networks would be separated in frequencies, effectively isolating them from each other. The limited frequency range used for WiFi limits the number of networks and therefore this is not a considerable solution to this work. If an effective layout of the devices would be possible this would separate the networks in space. As the space for this work is limited this is not possible. 14 2 Background Algorithm 1 An example of measuring throughput from client to server with iperf. This will open a TCP connection and transfer data with as high throughput as possible for 10 seconds. # On the s e r v e r d e v i c e ( IP 1 9 2 . 1 6 8 . 1 . 1 0 3 ) i p e r f −s # On the c l i e n t d e v i c e i p e r f −c 1 9 2 . 1 6 8 . 1 . 1 0 3 Algorithm 2 Use UDP with iperf, this sends UDP packets with 1 Mbit/s for 10 seconds from client to server. # On the s e r v e r d e v i c e ( IP 1 9 2 . 1 6 8 . 1 . 1 0 3 ) i p e r f −s −u # On the c l i e n t d e v i c e i p e r f −c 1 9 2 . 1 6 8 . 1 . 1 0 3 −u 2.6 Tools This part shows the most important tools used in this work, what they are capable of and used for. Iperf Iperf is a tool to measure throughput between devices in a network, it is a command line tool and so you need access to a console on the devices. To measure the throughput between two devices you set up a iperf server with the command iperf -s [optional flags]. The other device connects to the server with the command iperf -c <server-ip> [optional flags]. An example can be seen in algorithm 1, this would set up a TCP connection by default and transfer data from the client to the server with the highest throughput possible for 10 seconds. The tool also gives the opportunity to use UDP which is less reliable, but very useful for testing reliability. Algorithm 2 shows an example of measuring with UDP. This example would send UDP packets with a bandwidth of 1 Mbit/s from client to server for 10 seconds also showing jitter and packet loss. There are more flags that I have used to really embrace the power of iperf, some of these can be seen in algorithm 3. To view all available flags you can use the command iperf - -help. 2.6 Tools 15 Algorithm 3 Examples of optional flags that uses the power of iperf. # TCP # On the s e r v e r d e v i c e ( IP 1 9 2 . 1 6 8 . 1 . 1 0 3 ) i p e r f −s # On the c l i e n t d e v i c e # Measure f o r 60 seconds and output data as CSV # One row every 5 seconds i p e r f −c 1 9 2 . 1 6 8 . 1 . 1 0 3 − t 60 − i 5 −− r e p o r t s t y l e C # UDP # On the s e r v e r d e v i c e ( IP 1 9 2 . 1 6 8 . 1 . 1 0 3 ) # Setup a s e r v e r with UDP i p e r f −s −u # On the c l i e n t d e v i c e # Measure f o r 30 minutes with a bandwidth o f 20 Mbit / s # Output measurements every second i p e r f −c 1 9 2 . 1 6 8 . 1 . 1 0 3 −u − t 1800 −b 20M − i 1 Output The output from iperf gives timestamp, throughput, number of transferred bytes and for UDP (User Datagram Protocol) it also gives jitter and lost packets. An example output can can be seen in figure 2.9. In this example the default configuration is used but with 2 seconds interval between reports. The default configuration is using a TCP (Transmission Control Protocol) connection and sending data from client to server during 10 seconds. It is also possible to get Comma Separated Values (CSV) output with the command iperf - -reportstyle C with the output seen in figure 2.9c. Wifi Analyzer Wifi Analyzer [1] is an android app that is able to: 1. List all available WiFi networks with Received Signal Strength Indicator (RSSI) in dBm 2. Measure RSSI of all detectable networks over time 3. Show a graph of what channel is used by which network The tool is useful to quickly get more information about available networks but also to measure RSSI over time for a network. 2 16 Background (a) Iperf output on server side. (b) Iperf output on client side. (c) Iperf output when using CSV output. Figure 2.9: iperf output when using default configuration with 2 seconds interval between reporting. 2.6 Tools 17 Figure 2.10: A frequency analyzer showing the frequency spectrum for signals at 5.26 GHz with a span of 40 MHz. Frequency analyzer When measuring signal power or analyzing WiFi signals it is not possible to measure the air with a normal oscilloscope as the signals are sharing the same medium. With a frequency analyzer it possible to view signals in the frequency spectrum. This makes it possible to view and measure signal power, bandwidth and a graph of the used frequencies. A picture of a frequency analyzer is shown in figure 2.10. 3 Wired setup On each device the antennas are removed and replaced with radio frequency cables. The devices will operate normally but the physical medium (normally this is the air) is replaced by wires. The setup can be seen in figure 3.1, the orange box is the access point connected with 4 U.FL to SMA cables to 4 attenuators. These 4 attenuators are then combined with the 4-way combiner seen as the first blue box. A SMA to SMA cable connects the 4-way combiner to the 8-way splitter splitting the signal to 8 outputs. These are connected with SMA to SMA cables with 8 attenuators. All attenuators are connected with SMA to U.FL cables to the 4 set-top boxes, two cables per set-top box. The picture in figure 3.1b shows only a single set-top box connected and has terminators on all other outputs on the 8-way splitter/combiner. AP 4 comb. 8 split 1113W 1113W 1113W 1113W (a) A drawing of the wired network. (b) A camera picture of the setup seen from above. Figure 3.1: The wired setup as a drawing and a picture from above. 19 3 20 (a) U.FL antenna connector as seen in a AVM Fritz!Box Fon WLAN 7170 (CC BY-SA 3.0). Wired setup (b) Male SMA connector, 50 ohm, manufactured by Huber+Suhner (CC BY-SA 3.0). Figure 3.2: An U.FL connector (a) and an SMA connector (b), the U.FL connector is only 2 mm in diameter while the SMA connector is about 8 mm in diameter. Table 3.1: List of components used in this setup Description Attenuator 30 dB Cable 16 inch Cable 24 inch 4 way splitter/combiner 8 way splitter/combiner Terminator U.FL to SMA cable Model number VAT-30+ 086-16SM+ 086-24SM+ ZN4PD1-63-S+ ZN8PD-642W-S+ ANNE-50+ Quantity 12 9 4 1 1 8 12 3.1 Components All the components used in the setup can be seen in table 3.1. These components were bought from Mini Circuits and complemented with terminators for any open port during testing. The U.FL to SMA cables were bought from Ebay. An U.FL connector is shown in figure 3.2a next to the SMA connector in figure 3.2b. Slitter/Combiner There are two splitter/combiners, one 4-way and one 8-way. These splits the signal into 4 or 8 signals or it combines the signals into one. When the signal is split the power of the signal is also divided with the number of outputs. The 4way splitter/combiner will split the signal into 4 and therefore the signal power will be 41 of the original signal. When multiple signals are combined the signals instead gets added and a 4-way combiner will summarize the signals to 4 times the original signal power. The splitter/combiners also has insertion loss which 3.2 Attenuation between components 21 further attenuates the signal. Terminator A terminator is used to stop the signal and has matched impedance which absorbs the signal, it also has very little reflection. 3.2 Attenuation between components Normally the air is attenuating the signal and the devices are not built to receive too high power. When wiring the antennas together it is important to attenuate the signal to save the electronics in the devices. The attenuation between different components in the system are calculated with formula 3.1, 3.2 and 3.3 where A is the attenuation, L is the insertion loss and I is the isolation. Insertion loss is the attenuation of the signal when the component is inserted into the system and isolation is the attenuation between different parts of a component, e.g. between outputs of the splitter/combiners. AAP−to−settop−box AAP−to−AP = = Asettop−box−to−settop−box 2 ∗ (AV AT −30+ + LV AT −30+ ) + 3 ∗ L086−16SM+ + LZN 4PD1−63−S+ + LZN 8PD−642W −S+ 2 ∗ (AV AT −30+ + LV AT −30+ ) + 2 ∗ L086−16SM+ + IZN 4PD1−63+ = 2 ∗ (AV AT −30+ + LV AT −30+ ) + 2 ∗ L086−16SM+ + IZN 8PD−642W + (3.1) (3.2) (3.3) AAP−to−settop−box in equation 3.1 shows the attenuation from one connector of the access point through the entire system to one connector at the set-top box. AAP−to−AP in equation 3.2 shows the attenuation from one connector of the access point to another connector of the access point. Asettop−box−to−settop−box in equation 3.3 shows the attenuation from one connector of the set-top box to another connector of the set-top box. 22 3 Wired setup 3.3 Throughput The throughput provided by the setup is critical to this work. The goal is to be able to stream 20 Mbit/s video to each set-top box. In WiFi the data will be unicasted to each set-top box and so the access point needs to be able to deliver N ∗ 20 Mbit/s where N is the number of set-top boxes. This is because WiFi will not multicast the data because the modulation of that signal needs to be very low, by unicasting the data the modulation could be as high as possible for each device, leading to higher throughput. 3.4 Reliability The system needs to be reliable, especially if the set-top boxes are only connected with WiFi. The network may use TCP or UDP traffic and as TCP is more reliable in design the throughput is most important in this case. With UDP traffic there may be lost packets, jitter (the deviation from true periodicity) and packets received in the wrong order. Therefore the reliability tests are measuring these three properties of UDP traffic. 4 Encapsulation The network could further be isolated with encapsulation. Two types of encapsulation has been considered in this work: • Create faraday cage to isolate network • Buy pre made RF-shielding enclosures 4.1 Faraday cage Faraday cages can be used to isolate the network from other networks or noise. Depending on the background noise and how well the networks are shielded, faraday cages are an option that may isolate the network. Calculations The wavelength of a 5 GHz signal, as calculated in equation 4.1, is 0.06 m (6 cm). λ= v c 299792458 = 0.060 m = = f f 5 ∗ 109 (4.1) Equation 4.2 shows the penetration depth or skin depth, it is the depth in the metal where the power attenuation is exponential [7]. The penetration depth is relative to resistivity ρ, frequency f , and permeability µ. δs = r ρ π∗f ∗µ (4.2) Using equation 4.2 the values in table 4.1 can be calculated for 2.4 GHz and 5 GHz. 23 4 24 Encapsulation Table 4.1: Skin depth for different materials at different frequencies[5] Material Aluminum Copper Iron Resistivity [µΩ ∗ cm] 2.65 1.69 10.1 Permeability µr 1 1 500 Skin depth at 2.4 GHz [µm] 1.672 1.336 0.146 Skin depth at 5 GHz [µm] 1.159 0.925 0.101 Figure 4.1: A simple faraday cage made with aluminum foil. If the desired attenuation is known the depth could be calculated relative to the skin depth with equation 4.3 where D is the desired attenuation. With a desired attenuation of 90 % of the signal power, a total of 2.3 δ is needed. For aluminum with skin depth 1.159 µm the thickness needed at 5 GHz is 2.3 ∗ 1.159 µm = 2.67 µm. −x e δs x = D = −δ ln D (4.3) Aluminum foil cage This cage is made with one layer standard aluminum foil used in cooking. This foil has no holes and has a thickness of 0.010 mm. Material • Aluminum foil 4.2 RF-shielding enclosures (a) The two RF-shielding enclosures, the larger one fits the entire network and the smaller one fits only the Access Point or a VIP1113W device. 25 (b) The wired network set up in the larger RF-shielding box with two VIP1113W devices connected. An ethernet cable is connected to a DHCP router outside. A laptop is also connected to the same network. Figure 4.2: The RF-shielding enclosures and a network inside. • Grounding cable • Cardboard box The cage needs to be created so that no large holes are present. An antenna for measurements needs to be inserted into the cage resulting in at least one opening for a SMA-cable (about 0.4 cm in diameter) is needed. The picture in figure 4.1 shows a faraday cage made with cardboard and covered with aluminum foil. Microwave oven Microwave ovens use 2.4 GHz and are therefore made to shield these frequencies. If the holes in the cages are small enough this should theoretically also shield 5 GHz waves. 4.2 RF-shielding enclosures RF-shielding enclosures are pre made shielding boxes for radio frequencies. For this thesis work the manufacturers JRE testing and Ramsey were considered since they seem to be the most recognized. Two RF-shielding enclosures from JRE testing was ordered, one larger that fits the entire network and one smaller that only fits a single device, these can be seen in figure 4.2a. This makes it possible to test different setups. The datasheets for the RF-shielding enclosures can be seen in appendix B. These has an attenuation of more than 80 dB for frequencies of 5 GHz. The entire network fits in the larger RF-shielding enclosure which has the outside dimensions of 13" H x 17" W x 24" (0.38 m x 0.43 m x 0.61 m). 26 4 Encapsulation Isolation The isolation is the most important aspect of these enclosures and the goal is that the network should not be visible from outside and the enclosed devices should not be able to find any other network. The wired setup was placed in the larger RF-shielding enclosure as seen in figure 4.2b to be able to measure the isolation from other networks. The Received Signal Strength Indicator (RSSI) was used to measure the signal strength of WiFi routers. If no network is found from the enclosed devices this is an strong indication of that the RSSI values received are too low or not even recognized. When the entire network is enclosed the devices are still accessible from outside through ethernet and it is possible to query for other networks. 5 Result 5.1 Wired setup Measurements for the wired setup are made for isolation, throughput and reliability. Isolation This wired setup was evaluated and it worked well except it both sends out signals to outside networks and receives signals from outside networks. Measurements were done with near field probes at the positions specified in figure 5.1a. As seen in figure 5.1b the measured signal power at the antenna connectors (position 1 and 11) were very strong, this is probably where signals from other networks gets in to the system. Because the access point has 4 antennas and the set-top boxes has 2 antennas each, there will be 12 possible leakage points to isolate. The isolation from outside networks can be seen in figure 5.2. This was measured with the wired network setup and a smartphone with the Wifi Analyzer android app. The values are almost equal and the wires does not provide any practical isolation as the signal power of Network 1 needs to be attenuated at least 30 dB for the network to be isolated. Attenuation between components The attenuation in the system was measured by connecting one antenna output of the access point with a frequency analyzer and measure the signal power. I used iperf with default settings to send data through the system to get a high signal power. The signal power on one antenna of a set-top box was measured with the same signals sent and the difference in these measurements gives the 27 5 28 2 1 4 5 3 AP 6 7 4 comb. 8 split 8 1113W 1113W 9 11 10 (a) Measuring setup with numbered measuring points, these are provided in the parenthesis in figure 5.1b. Signal leakage Wires from 8 way splitter to attenuators before box (8) wireless DTV box 1113W (11) Wire from AP to attenuators (2) U.fl. to SMA cable from box (10) Attenuator after box (9) Attenuator after AP (3) All 4 SMA to SMA cables 16 inch (5) Access Point (1) A single SMA to SMA cable 16 inch after AP (4) 8 way splitter/combiner (7) 4 way splitter/combiner (6) −60 −40 −20 0 dBm (b) Signal leakage from different parts of the setup, measured as close as possible (0–4 mm) to the hardware. Smaller bars means greater power. Figure 5.1: Signal leakage from setup Result 5.1 Wired setup 29 0 RSSI values of other networks ● Network 1 Network 2 −40 ●● ●● ●● −60 ●●● ●●● −80 RSSI value [dBm] −20 ● ●●●● ●● −100 ●●●● ●● With wires Without wires [dBm] With wires [dBm] Attenuation [dB] Without wires RSSI network 1 −45.50 ± 1.87 −50.33 ± 0.82 4.83 dB RSSI network 2 −86.83 ± 0.9 −88.17 ± 1.17 1.34 dB Figure 5.2: Measured RSSI values of other networks. The values are comparable between wired network and without wires. 5 30 Result Table 5.1: Values for attenuation in the system Abbreviation AAP−to−settop−box AAP−to−AP Asettop−box−to−settop−box Calculated value [dB] 72.02 104.54 85.18 Measured value [dB] 73.8 no measurement a no measurement a a This value is to low to measure with the provided equipment Table 5.2: Values for attenuation A, loss L and isolation I for the components in the wired network. Datasheets for all components can be seen in appendix C. Component AV AT −30+ LV AT −30+ L086−16SM+ LZN 4PD1−63−S+ LZN 8PD−642W −S+ IZN 4PD1−63+ IZN 8PD−642W + Attenuation/Loss/Isolation [dB] 28.72 0.35 1.02 0.7 10.12 26 25 attenuation AAP−to−settop−box = 73.8 dB. This is very close to the theoretical value AAP−to−settop−box = 72.02 dBm calculated with equation 3.3 with values from table 5.2. The values for AAP−to−AP and Asettop−box−to−settop−box was not possible to measure as the signal power was to low for the frequency analyzer to pick up. The calculated values are AAP−to−AP = 104.54 dB from equation 3.2 and Asettop−box−to−settop−box = 85.18 dB from equation 3.3. The attenuation between different parts of the system can be seen in table 5.1. Throughput In the measurements the AP is using a 20 MHz bandwidth and throughput is measured with the tool iperf and a TCP (Transmission Control Protocol) connection if nothing else is mentioned. A laptop is used to initiate tests and connect to the set-top boxes. The laptop and access point are connected to a router that has a maximum throughput of 100 Mbit/s which could be a limiting factor in these tests. Laptop and one set-top box Figure 5.3 shows the throughput from the laptop to a set-top box. The 100 Mbit/s router may be a limiting factor in the test but the throughput is high in both directions. In this test the access point was set to use 80 MHz bandwidth. 5.1 Wired setup 31 Throughput between laptop and set−top box 100 Mbit/s 75 Laptop to set−top box 50 Set−top box to laptop 25 0 0 30 60 90 120 Seconds From laptop to set-top box From set-top box to laptop Throughput [Mbit/s] 86.62 ± 1.50 56.69 ± 2.03 Figure 5.3: Measured throughput between a laptop and a set-top box. The throughput is higher from laptop to set-top box than from set-top box to laptop. 5 32 Result Throughput from two set−top boxes to laptop 100 Mbit/s 75 Combined throughput 50 Set−top box 1 Set−top box 2 25 0 0 25 50 75 100 Seconds Set-top box 1 Set-top box 2 Combined throughput Throughput [Mbit/s] 28.83 ± 4.33 27.54 ± 4.62 56.38 ± 1.56 Figure 5.4: Measured throughput from two set-top boxes to the laptop. Laptop and two set-top boxes The throughput from a two set-top boxes to the same laptop was measured by creating a server on a laptop connected to the AP with the command iperf -s. Both set-top boxes connected to the laptop with the command iperf -c <ip> and measured for 120 seconds. Figure 5.4 shows the throughput which are varying, but the combined throughput is comparable with the throughput from a single set-top box to the laptop seen in figure 5.3. In this test the AP was set to use 80 MHz bandwidth. The throughput in the reverse direction, from the laptop to two set-top boxes was measured during 120 seconds with iperf by creating two servers (iperf -s), one on each set-top box and then connecting from the laptop to the two set-top boxes simultaneously (in two separate terminals call iperf -c . . .). The measured throughput can be seen in figure 5.5, the throughput is stable and variation is small. The combined throughput is about 90 Mbit/s which is high when 5.1 Wired setup 33 Throughput from laptop to two set−top boxes 100 Mbit/s 75 Combined throughput 50 Set−top box 1 Set−top box 2 25 0 0 30 60 90 Seconds AP to set-top box 1 AP to set-top box 2 Combined throughput Throughput [Mbit/s] 42.09 ± 0.39 47.69 ± 0.61 89.77 ± 0.72 Figure 5.5: Throughput from laptop to two set-top boxes. the router limits the throughput to 100 Mbit/s, it is also comparable to the measurement in figure 5.3. Reliability To measure the reliability the setup was tested by sending UDP packets with 1 Mbit/s for 1 hour in both directions simultaneously. The results shown in table 5.3 shows that there are some jitter but out of 321 000 packets sent no packets were lost. When streaming video to the set-top boxes there will mostly be traffic from the laptop (or a server) to each set-top box. The traffic will be using UDP packets and it should be possible to send streams with 20 Mbit/s bandwidth. This was tested by using iperf and from the laptop making two parallel 20 Mbit/s UDP streams to each set-top box. This would simulate 4 simultaneous 5 34 Result Table 5.3: Reliability of the wired setup when isolated measured with 1 Mbit/s UDP packets for 1 hour. There are no packets lost out of 321 000 sent packets. Laptop to set-top box Set-top box to laptop Jitter [ms] 0.227 0.102 Packet loss [%] 0 0 UDP streams with 20 Mbit/s bandwidth through the network. The result can be seen in table 5.6, the throughput is 19.07 Mbit/s, the jitter is 0.73 ms and there are no lost packets. 5.2 Encapsulation Both faraday cage and RF-shielding enclosures were tested as well as a microwave oven as they shield 2.4 GHz waves very well. Aluminum foil cage Figure 5.7 shows the measurements of 2 faraday cages with different number of layers of aluminum foil with a thickness of 0.010 mm. There is no sign of the cages reducing the power significantly. Microwave oven The measurements were done by putting a Google Nexus 5 phone (Android phone that has 5 GHz band for WiFi) in a microwave oven and measure the Received Signal Strength Indicator (RSSI) with door open and closed. The measurements can be seen in figure 5.8, the 5 GHz signal is attenuated about 20 dB in a Microwave oven but this is not enough. RF-shielding enclosure With the lid open the network with highest RSSI value has RSSI = −54 dBm but when the lid is closed no networks can be found by the devices from within the enclosure. From outside I am able to view all networks with the Wifi Analyzer android app [1]. When closing the lid on the larger RF-shielding enclosure the RSSI value for the enclosed network drops and the network is not even recognizable, this can be seen in figure 5.9. With the lid closed it is not possible to find the network with the Wifi Analyzer android app. 5.2 Encapsulation 35 Throughput from laptop to 4 set−top boxes 25 20 15 Mbit/s Set−top box 1 Set−top box 2 Set−top box 3 Set−top box 4 10 5 0 0 500 1000 1500 Seconds Mean throughput Mean jitter Lost packets Sent packets 19.07 ± 0.02 Mbit/s 0.73 ± 0.02 ms 0 820 135 286 Figure 5.6: Result of 4 parallel measurements from laptop to two set-top boxes (2 parallel to each set-top box). 5 36 Result ●●● ●●● ●●●● ● −20 Power [dBm] −10 0 Peak power in faraday cage made of aluminum foil ●● ●● ●●● ●●●●● ● ●●● ● ●● ●●● ● ● ● ●● −30 ● ●● ● ● −40 ● No cage No cage 1 layer aluminum 2 layers aluminum 1 layer aluminum Power [dBm] −18.50 ± 3.37 −19.82 ± 4.25 −21.80 ± 3.12 2 layers aluminum Power [µW ] 16.7 ± 6.38 13.4 ± 5.82 8.08 ± 4.67 Attenuation [%] 0 20 52 Figure 5.7: Measurements of faraday cage made of aluminum foil with one and two layers. There are no significant attenuation by any of the faraday cages. 5.2 Encapsulation 37 (a) Measurements of Received Signal Strength Indicator (RSSI) in an open microwave at 2.4 GHz (b) Measurements of Received Signal Strength Indicator (RSSI) when closing the microwave at 2.4 GHz. The drop in RSSI is when closing the door. (c) Measurements of Received Signal Strength Indicator (RSSI) in an open microwave at 5 GHz (d) Measurements of Received Signal Strength Indicator (RSSI) in an closed microwave at 5 GHz Figure 5.8: Measurements of Received Signal Strength Indicator (RSSI) in a microwave for 2.4 GHz and 5 GHz with the WiFiAnalyzer app for Android[1]. The Microwave shields the 2.4 GHz signal but the 5 GHz signal is only attenuated about 20 dB. 38 5 Result Figure 5.9: Closing the lid on the RF-shielding enclosure. The Received Signal Strength Indicator (RSSI) value are very well shielded. 6 Discussion Discussion of the final solution, the considered solutions and other important parts of this work. 6.1 Wired setup The wired setup seems to work well and are probably very close to the air as physical medium. I think that multiple spacial streams or beam forming may not work as all the wires are interconnected. This is something that I have not been able to measure. 6.2 WiFi technology Because of how WiFi works the isolation makes it possible to use any channel and also reuse the same channel for all networks if you will. It is also then possible to use a 80 MHz or 160 MHz bandwidth for every network. 6.3 Throughput The throughput is high and will be enough to provide 20 Mbit/s to 4 devices and at the same time sending smaller packets in the reverse direction, back to the laptop/server. This is necessary to be able to receive status and log messages from the devices during testing. The attenuation is currently high in the system, if the attenuation is too high the modulation of the signal will be lower and the throughput lower. This could be solved by using attenuators with lower attenuation, I think 20 dB or 15 dB 39 40 6 Discussion should be enough and that the devices could receive a signal strength that is 30 dB higher (if 15 dB attenuators are used instead of 30 dB). 6.4 Isolation Three different solutions were tested for network isolation: wires, faraday cages and RF-shielding enclosures. RF-shielding enclosures was definitely the best option with very good isolation of the network. Wires The wired setup has almost no isolation. I think this is because of the strong leakage points shown in figure 5.1. If these could be shielded the total isolation of the wired setup would be higher and encapsulation may not be necessary. Faraday cages The faraday cages made of aluminum foil did not give any good result or measurements. The measurements changed when rotating the cage. This is probably due to the fact that it is not entirely sealed and that every opening gives signals a way to escape or enter the cage. Also all cables may lead signals from outside into the faraday cage. I was not able to create any better faraday cage and therefore an alternative was needed. The thickness I used for the aluminum cages should be enough as calculated with the skin depth in equation 4.2. But thicker aluminum foil could maybe shield more. I did not test to add absorbing foam because I did not find any good provider that I could buy the foam from. I think that this could reduce the reflections in the cage and this is something that is used in the RF-enclosures used in this work. Microwave The microwave attenuated less for 5 GHz than 2.4 GHz frequencies, my guess is that the holes used were to large to fully attenuate 5 GHz waves or that connectors into the microwave are filtered for 2.4 GHz and not 5 GHz. RF-shielding enclosures The RF-shielding enclosures with 80 dB attenuation of signals provides very good isolation of the network. With WiFi’s threshold of the signal power being larger than -82 dBm, a 80 dB attenuation should remove any WiFi signal from outside as they are in reality always less than 0 dBm. The RF-shielding enclosures are large and heavy but they do keep the network modular and simple with a single box. As all the connectors need to be filtered it is hard to alter the connectivity options when the enclosure has been ordered. If 6.5 Reliability 41 changes needs to be made a new connector plate with the configuration wanted needs to be ordered. The RF-shielding enclosures are also expensive. I ordered the RF-shielding enclosures from JRE instead of Ramsey even though they had similar RF-shielding enclosures. The reason for choosing JRE was that they had a lower price and offered faster manufacture and delivery time. Cooling Access point, set-top boxes, transformers and electricity regulators all get hot. The RF-shielding enclosure has ventilation but is otherwise air tight and it may be to hot inside. This is something that I have not tested but that I think will work well if the equipment inside are not blocking the ventilation. 6.5 Reliability The system are reliable and works like a normal WiFi. The isolation has the benefit that there will be no waiting when other networks sends data on the same channel, and all channels are available to the enclosed network. 6.6 Measurements When measuring throughput and reliability I have been using the tool iperf which works well. I have only had two set-top boxes to test with and therefore I was not able to test more devices. When measuring signal strength with the frequency analyzer a problem has been that the access point will not send data without any connected device. This has been solved either by only listening to the beacons sent out automatically or by using only one antenna of the AP for measurements and connecting wirelessly with the laptop to the other 3 antennas. 6.7 Adoption in KATT The system has been tested to work with ARRIS KreaTV Automated Test Tools (KATT) and it is possible to stream video streams to the set-top boxes without any lost packets. The set-top boxes are also sending log data back without any problems. 7 Conclusion In this work two types of techniques has been combined to provide isolation of a WiFi network. The wired setup has high throughput and good reliability but the isolation is low. The RF-shielding enclosure provides very good isolation and the combination of these two techniques creates a good solution to the problems. With this solution only 4 set-top boxes are connected to the access point, this provides high throughput but the number of set-top boxes is low. As the network is isolated from other network it is possible to place multiple networks side by side to provide high throughput to a large number of devices. The entire network fits in a single RF-shielding enclosure and the physical space of this is small compared to the environment. 7.1 Wired setup The wired setup works and communication between different devices has high throughput and is capable of providing 20 Mbit/s UDP streams from the laptop to 4 set-top boxes in parallel. The throughput from laptop to set-top boxes are slightly higher than in the reverse direction. The network is also reliable with no lost packets during one hour with 1 Mbit/s UDP stream in both directions between the laptop and a set-top box. This shows that the network is reliable with good performance and very low loss. The wires only isolates slightly and the setup does not have enough isolation from other networks, it is not possible to use only the wired setup as a solution to this master thesis work. 43 44 7 Conclusion 7.2 Encapsulation Both faraday cages and RF-shielding enclosures were considered and tested to be used as encapsulation to further isolate the network. Faraday The faraday cages made of aluminum foil did not isolate enough and were very unreliable, there were no significant attenuation of the signal. The test of microwave ovens showed about 20 dB attenuation for 5 GHz but this is not enough for this work. Microwave ovens are also too expensive and demanding to work with compared to smaller aluminum cages or the RF-shielding enclosures. RF-shielding enclosure The RF-shielding enclosures have a high attenuation of 80 dB for 5 GHz waves. This was proven to be enough as the enclosed network is not detectable from outside and the enclosed devices detects no other network than the enclosed network. Because everything fits within the larger RF-shielding enclosure it is easy to expand the solution with more enclosures, one for each new network. Using only the larger RF-shielding enclosure was the best option even though it is possible to use both RF-shielding enclosures with a SMA-cable in between. 7.3 Final solution The final solution is a wired setup where the antennas of each device has been interconnected and this replaces the air as a physical medium. This wired network is enclosed by a RF-shielding enclosure to isolate it from other networks. The solution is an isolated network that is not detectable from outside and works with the WiFi standard without modifying any software in the devices. 8 Future Work In this chapter there are some ideas that could be useful to evaluate in future work. These are ideas that I have stumbled upon or did not have time to evaluate myself. 8.1 Single antenna wired setup In the current setup all antennas are connected to the wired setup. This mimics the default behavior and usage of the devices as they are all connected to the air in the normal case. As described in section 6.1 all the WiFi features may not be applicable. Using only one antenna per device may work just as good as connecting all antennas. With this setup the number of components used will be smaller. The setup could be reduced to only 5 attenuators, 5 U.FL to SMA cables, one 4-way splitter/combiner, 4 set-top boxes and the access point. This will reduce the cost of the setup. This could also make it possible to connect 8 set-top boxes instead of 4 if the 8-way splitter is used instead of the 4-way splitter. This system would use 9 attenuators, 9 U.FL to SMA cables, one 8-way splitter/combiner 8 set-top boxes and the access point. 8.2 Wireless setup in RF-shielding enclosure Because the wires does not isolate the network much they may not be needed. All the wireless devices could fit in the RF-shielding enclosure normally, without the wires and this would make the solution easier and cheaper. There are problems with this idea that could arise, the devices should not be to close and when using 45 46 8 Future Work antennas the signal power sent out is larger so the RF-shielding enclosure may not be able to attenuate it enough for the network to be isolated. All the measurements needs to be redone and I have not been able to test this due to the limited time. 8.3 More set-top boxes per AP In the current measurements the throughput is constrained by the 100 Mbit/s router. If the router is replaced by a faster router and the throughput between devices is enough, more set-top boxes could be added to the system. Bibliography [1] Wifi analyzer. https://play.google.com/store/apps/details? id=com.farproc.wifi.analyzer. Accessed: 2015-01-05. [2] Ieee std 802.11ac -2013, 2012. http://www.wi-fi.org/ [3] Wi-Fi Alliance. Wi-fi certified ac. discover-wi-fi/wi-fi-certified-ac, 10 2014. Accessed: 2014-1008. [4] WiFi alliance. Certification. http://www.wi-fi.org/certification, 10 2014. Accessed: 2014-10-08. [5] Kirt Blattenberger. Skin depth. http://www.rfcafe.com/ Accessed: 2014-10references/electrical/skin-depth.htm. 14. [6] ETSI. Etsi en 301 893 v1.7.0. http://www.etsi.org/deliver/etsi_ en/301800_301899/301893/01.07.00_40/en_301893v010700o. pdf, 2012. [7] M M J French. Mobile phone faraday cage. http://arxiv.org/pdf/ 1112.5495.pdf, 2009. [8] Matthew Gast. 802.11 Wireless Networks: The Definitive Guide. O’Reilly Media, 4 2002. [9] Matthew Gast. 802.11ac: A Survival Guide. O´Reilly, 2013. [10] Hakim Weatherspoon Ji-Yong Shin, Emin Gün Sirer. On the feasibility of completely wireless datacenters. http://www.cs.cornell.edu/ ~jyshin/papers/ancs2012_shin.pdf, 2012. [11] LitePoint. Ieee 802.11ac: What does it mean for test? http://litepoint. com/whitepaper/80211ac_Whitepaper.pdf, 2013. [12] Inc Meru Networks. Understanding the ieee 802.11ac wi-fi standard. http://www.merunetworks.com/collateral/white-papers/ wp-ieee-802-11ac-understanding-enterprise-wlan-challenges. pdf, 2013. 47 Appendix 49 A Considered methods Here follows methods that may potentially solve the problem. They will be evaluated and the best solution will hopefully be possible to use. The methods are chosen to be as simple as possible to make the evaluations specific. They are all using the 802.11ac standard on the 5 GHz band if nothing else is mentioned. A single access point A single AP may use the widest 160 MHz channel and the setup will be simple. This method will be used mostly as a comparison when describing other methods. Pro 1. Simple setup 2. Large bandwidth, could use 160 MHz channel Against 1. Does not use all available bandwidth 2. Many clients connected to a single AP (a) Only a limited number of clients may connect to a single AP 3. Throughput will be shared by clients 4. Single point of failure, if AP is down, every client is disconnected 51 A 52 Considered methods Channel sharing Multiple Access Points sharing the same channel (bandwidth). In this simple setup all APs share the same channel. Pro 1. Large bandwidth, could use a 160 MHz channel 2. No single point of failure, if one AP is down the other APs may still be working, clients could switch to available APs 3. Many connected clients because each AP only connects a small group of clients Against 1. Throughput will be shared by clients 2. Does not use all available bandwidth Dual band Using both the 2.4 MHz band and 5 GHz band enables more bandwidth. The structure may also be used in a way which makes the 2.4 MHz band used for normal data and the 5 GHz band for streaming video. Pro 1. Very large bandwidth Against 1. More complex structure (a) Multiple bands (b) More complex channel selection 2. Noise from current 2.4 GHz usage Isolated environments using Faraday cages Faraday cages may be used to create smaller isolated environments where each environment has no influence or noise from surrounding environments. A faraday cage is shown in figure A.1. 53 Figure A.1: A faraday cage with holes. Pro 1. Channels may be reused 2. Both bands may be reused 3. Noise from networks outside lab may not influence the isolated environments Against 1. Cost, material is needed to build the cages 2. Complexity, the cages needs to be built with good precision to isolate from surrounding noise 3. Handling, when administration is needed it will be harder to work with the clients when inside cages 4. Electricity, the faraday cages needs to be grounded 5. Cooling, the faraday may have holes but are the ventilation enough to provide good cooling inside As long as the electrons could move around the holes the hole size will not matter much to the cage. But for this to work they typically needs to be much smaller than the wavelength. Cage 1 Material: • One layer aluminum foil • Ground cable The cage is built using one layer aluminum foil and connected to ground. A 54 Considered methods Isolate with absorbing materials There are materials that are good for absorbing radio frequency signals. These may be used to isolate or absorb signals from other APs or networks. This may be used to create layers, floors or walls in any structure. Some of the materials are possible to have air flowing through them. Pro 1. Channels may be reused, if isolated enough 2. Create other structures than boxes 3. More noise resistant Against 1. Fire, most of the materials are fire resistant but this needs an extra thought so that they are not flammable 2. Cooling, these materials are often air flow resistant Connecting antennas with wires If the antennas on the APs are directly connected to the clients there are no noise. An AP may be connected to multiple clients with a Y adaptor splitting the antenna cable. Pro 1. No noise from other devices 2. The throughput will always be enough with enough APs Against 1. Cost, antenna cables, splitters and enough APs 2. Connection/adapter to clients needed 3. Abnormal, network testing may not be as with the customers Scheduling By scheduling tests there may always be available throughput. This means that the tests may take longer to finish. 55 Pro 1. The required throughput will be available when necessary 2. Predictability, with a redundant network the network will be predictable and stable Against 1. Not normal, this is not exactly as the network will be used with the customers 2. Complexity, the scheduling needs to be done and UIs surrounding this 3. Tests may take longer Simulation Simulate WiFi traffic using software and connect this with some hardware that fits. Pro 1. Same throughput as with wires, depending on the hardware used Against 1. Not normal, the software needs to be really good to simulate WiFi in a good way 2. Complex, the simulation will be complex to make and bugs will be hard to find 3. Bugs in software Quality of Service By prioritizing the right packets in the APs, the latency will be lower for higher priority packets. Pro 1. Lower latency for video streams 2. Distributed traffic, no client will get all the traffic, instead all clients will get the same amount Against 1. Will not be enough to have high throughput A 56 Considered methods Antennas With the right antennas it will be possible to send only to the clients that are in the network, this will reduce noise for other networks. The antennas could be omnidirectional or directional. Pro 1. Less noise for nearby networks Against 1. Cost, special antennas has a high price 2. Complex, setting up antennas with their different angles will be complex, harder to change setup Absorb antenna signal by wrapping antennas with absorbing materials. Could this be used to make the signal attenuate more quickly and therefore make the density higher in the network? Extensive channel layout By using the channels in a good way it will be possible to use most of the available bandwidth. In figure A.2 channel addition is shown in the lowest frequency span of 5 GHz band in 802.11ac. The first AP chooses primary channels 40 for 20 MHz, 36–40 for 40 MHz and 36–48 for 80 MHz. The next AP chooses primary channels without overlap. When choosing channels for the third AP the 80 MHz channel needs to be shared, the same thing for the fourth AP. When adding a fifth AP also the 40 MHz channel needs to be shared. In the channel layout described above only up to 80 MHz channel widths are used, when adding 160 MHz this needs to be shared among all APs. Pro 1. Large bandwidth, as much as possible of the available bandwidth are used 2. No single point of failure 3. Dynamic use of available bandwidth Against 1. May not be enough to provide high throughput 2. Sharing channels means sharing throughput 57 Figure A.2: 802.11ac channel addition from “802.11ac: A Survival guide” [9]. All APs get as wide bandwidth as possible without sharing, and only when that is not possible do they share channels. Hexagonal 2D layout By using a 2D layout there is no need to care about 3D interference, meaning that the layout will be simpler. By using hexagonal network areas it is easy to create a layout where the channels are able to be re-used at a certain distance from each AP. If 80 MHz bandwidth channels are used 3 channels may be used and the left part in figure A.3 will be used for layout. Pro 1. Simple layout 2. Easy to calculate because it has only two dimensions Against 1. Uses a large area Cylinder layout A layered cylinder layout with APs in the middle and clients in racks at the edges. With good isolation between layers this could give a good throughput as each layer could be using a 160 MHz bandwidth. The racks could be of any size but will be dimensioned by the throughput requirements, the same goes for number of racks per layer. The racks makes it easy to handle clients. A 58 Considered methods Figure A.3: Channel re-use by using hexagonal network layout. (a) A single layer layout, AP in the center and multiple racks with multiple clients. (b) Side view of multiple layers, each layer are isolated from nearby networks. (c) A full cylinder with multiple layers. Figure A.4: Cylindric layout of APs and clients. Each layer can be seen as a separate network and a self contained module. Multiple modules will be stacked to make a cylinder. This layout can be seen in figure A.4. Pro 1. High throughput with multiple separated networks 2. Simple, a single AP in the center using a standard omnidirectional antenna 3. Space requirement is small 4. No single point of failure, if an AP goes down only a single layer will be affected 5. Makes use of MIMO (Multiple Input/Multiple Output) or MU-MIMO (Multi User MIMO) 59 Figure A.5: Rack view of a wireless datacenter design by Microsoft Research [10]. A cylindrical layout with multiple servers side by side in each layer. The servers are communicating with each other on both sides. The circles could be extended outwards with another layer of servers. Against 1. Cost, the radio frequency absorption materials has a high price 2. Risk, if there are noise between levels this will not work. (could be solved with different channels on each x:th layer, with a smaller throughput as result) 3. Cooling, because of the isolation between layers it will be hard to cool the devices. (Often the absorption material will also work as isolation of temperature) 4. Close between layers means higher noise in vertical direction This layout takes a lot of inspiration from the Microsoft research of a wireless datacenter [10] where they use the 60 GHz band with a range below 10 meters and cylinder layout. Instead of a single AP in the center they let the servers talk to each other directly as they are all facing inwards, as seen in figure A.5. A 60 Considered methods Figure A.6: Directional antennas used to isolate networks. Directional antennas By using directional antennas the networks could be separated and the channels reused, as seen in figure A.6. Pro 1. Channel reuse 2. Longer range is ok, signal propagation only in one direction, reflections could be a problem Against 1. Cost, antennas need to be bought. Antennas for the clients and also customizing them are costly and needs lots of work 61 2. Density, the network will not be as dense as would be possible with other layouts. Especially if the networks should be separated 3. Modulation, because the clients are at different distance from AP different modulation constellations may be used. The distance will also reflect the radio transmission used 4. If high throughput is required from client to AP then directional antennas must be used for each client as well Split up physically By splitting up the network physically by location they will not interfere with each other. Pro 1. Channel reuse, because the networks are isolated the channels may be used again 2. No single point of failure, because the networks are on different locations thy are also separated for failures in switches or failing AP Against 1. Cost, multiple locations are needed 2. Space, multiple locations are needed 3. Networking, connecting all the locations will be a challenge 4. Security, all the locations needs to be secure as well as the network between locations 5. Cooling, all locations needs cooling B JRE RF-shielding enclosures datasheets 63 Wireless RF Test Enclosures JRE 1724 RF Shielded Test Enclosure Our largest rack mountable enclosure - ideal for large scale RF devices • Roomy 22.5 x 15.5 x 11 inches inside • Fits on any benchtop or into any standard sliding 19" rack shelf • Rugged welded aluminum construction • Wide selection of I/O options with our universal I/O plate, easily interchangable too! • Large size for testing enterprise class Mesh Network systems, access points and laptops • Excellent RF Isolation at a low cost: $1495 Originally designed for testing wide screen laptops, the rackmountable JRE1724 is ideal for large wireless devices such as; Mesh Network AP’s, Cellular/LTE/4G Base Stations, and other large RF devices. Featuring rugged welded aluminum construction, you can be assured of its tight RF shielding effectiveness. Long life door gasket material along with double edge engagement not only provides solid RF shielding, but smooth trouble free operation over its lifespan. Internal struts keep the lid open for easy internal access when connecting the device under test. Our wide selection of I/O connectors allow almost any device to be interfaced inside the enclosure, and internal electromagnetic absorbing material reduces RF reflections and hot-spots. FEATURES & BENEFITS • Double contact door shields ensures repeatable measurements • 3/4” thick RF absorbing foam deadens standing waves • Heavy duty stainless steel friction hinges and struts • Rugged welded aluminum construction for long life • Wide variety of connector options for every use • Includes 80mm vent option, AC or DC fan optional CONNECTORS JRE 1724 I/O Interfaces RF Feedthru: BNC, TNC, SMA, SMB, UHF, TypeN, reverse SMA, reverse TNC Fiber optic: Fiber optic bulkhead feed thru: Type ST, FC. Fiber transceiver available for USB2.0 with speeds up to 480 MB/s Connector covers: Dust cover caps with tether chains included for all RF connectors RF filtered data connectors: DB9, DB15, DB25, DB37, DB50, RJ11, RJ45, USB (Choice of 100 or 1000 pf filtering on data lines) Universal I/O plate with incredible connector options. Easily changed in the field for multiple uses. Power connection: 4 or 6 terminal barrier strip, 2500 pf filtering. 120/240 VAC power strip ISOLATION Cover interlock switch: safety switch contact -100dB @ 1GHz, -90dB @ 3GHz, -80dB @ 6GHz DIMENSIONS Outside: 13" H x 17" W x 24" D Inside: 11" H x 15.5" W x 22.5" D JRE Test, LLC 1350 Pittsford-Mendon Rd. Mendon, NY 14506 www.jretest.com 888-430-3332 [email protected] Wireless RF Test Enclosures JRE 0709-A 802.11a,b,g RF Shielded Test Enclosure $749 Universal, preconfigured RF shielded test enclosure, ready to ship - immediately! • Roomy 3.25 x 6 x 8.5 inches inside • Fits on any benchtop • Already configured for 802.11a,b,g RF tests • Rugged welded aluminum construction • Adjustable latch ensures tight RF shielding • Excellent RF Isolation Save on this stock, ready-to-ship enclosure Custom price: $899 Ready-to-ship price: $749 ! Containing all the capability of the larger JRE enclosures, the compact JRE 0709-A is ideal for small wireless devices such as; 802.11a,b,g WLAN access points, VoIP devices and other small RF devices. Featuring rugged welded aluminum construction, you can be assured of its tight RF shielding effectiveness. Long life door gasket material along with double edge engagement not only provides solid RF shielding, but smooth troublefree operation over its lifespan. A popular configuration of I/O connectors allow almost any device to be interfaced inside the enclosure, and internal electromagnetic absorbing material reduces RF reflections and hot-spots. FEATURES & BENEFITS JRE 0709-A I/O Interfaces • Double contact door shields ensures repeatable measurements RF Feedthru: 2 each of SMA female bulkheads • 1/2” thick RF absorbing foam deadens standing waves and re flections for repeatable tests Adapter: one DB9 to RJ45 adapter • Heavy duty stainless steel hinge holds door steady • Rugged welded aluminum construction for long life Connector covers: Dust cover caps with tether • Wide variety of connector options for every use chains included for all RF connectors CONNECTORS One 100 pf filtered DB9 connector with RJ45 adapter One 1000 pf filtered DB9 connector Two SMA Female bulkheads 4 Terminal barrier terminal strip - 100VDC @ 20A ISOLATION -90dB @ 1GHz, -90dB @ 3GHz, -80dB @ 6GHz RF filtered data connectors: Dual DB9’s, one with 100 pf filtering, one with 1000 pf filtering - for wide range of data rates Power connection: 4 terminal barrier strip, 2500 pf filtering. Barrier strip cover included. Whip antennas: 2 each of 2.4 - 5.8 GHz whips DIMENSIONS Outside: 4.5" H x 7.25" W x 9.75" D Inside: 3.25" H x 6.0" W x 8.5" D JRE Test, LLC 1350 Pittsford-Mendon Rd. Mendon, NY 14506 www.jretest.com 888-430-3332 [email protected] C Mini Circuits datasheets 67 Coaxial SMA Fixed Attenuator 50Ω 0.5W 30dB Maximum Ratings VAT-30+ DC to 6000 MHz Features Operating Temperature -45°C to 100°C Storage Temperature -55°C to 100°C Permanent damage may occur if any of these limits are exceeded. • wideband coverage, DC to 6000 MHz • rugged unibody construction • off-the-shelf availability • very low cost CASE STYLE: FF704 Connectors Model SMA VAT-30+ Applications Price Qty. $13.95 ea. (1-9) +RoHS Compliant • impedance matching • signal level adjustment The +Suffix identifies RoHS Compliance. See our web site for RoHS Compliance methodologies and qualifications Outline Drawing Electrical Speciications .312 Across Flats in some models VSWR (:1) ATTENUATION * (dB) Flatness ** FREQ. RANGE (MHz) DC-3 GHz 3-5 GHz 5-6 GHz DC-6 GHz DC-3 GHz fL--fU Nom. Typ. Typ. Typ. Typ. Typ. Max. Typ. 3-5 GHz Max. Typ. DC-6000 30±0.3 1.10 0.70 0.35 1.30 1.05 1.20 1.15 1.30 1.25 MAX. INPUT POWER (W) 5-6 GHz 0.5 * Attenuation varies by 0.3 dB max. over temperature. ** Flatness= variation over band divided by 2. Outline Dimensions ( inch mm ) B .410 10.41 D 1.43 36.32 Typical Performance Data E wt .312 grams 7.92 10.0 Frequency (MHz) Attenuation (dB) 0.03 50.00 100.00 500.00 1000.00 30.05 29.99 29.96 29.33 28.79 1.00 1.00 1.01 1.02 1.04 2000.00 3000.00 4000.00 5000.00 6000.00 28.77 29.08 29.22 28.72 29.36 1.06 1.08 1.03 1.03 1.07 Electrical Schematic VAT-30+ VSWR VAT-30+ ATTENUATION 1.10 30.5 A 29.7 29.3 D R1 R3 FEMALE A 1.08 1.06 1.04 !! #" $ ! # ' () 1.02 D 30.1 R2 MALE VSWR (:1) &% 28.9 28.5 1.00 0 1000 2000 3000 4000 F Z 5000 6000 0 1000 2000 3000 4000 Z 5000 Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 350166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] 6000 REV. G M129173 VAT-30+ LC/TD/CP/AM 130923 Page 1 of 1 Termination 50Ω SMA ANNE-50+ DC to 18000 MHz Maximum Ratings Features Operating Temperature -55°C to 100°C Storage Temperature -55°C to 100°C Permanent damage may occur if any of these limits are exceeded. • wideband coverage, DC to 18000 MHz • return loss, 35 dB typ. up to 4000 MHz and 27 dB typ. 10000 to 18000 MHz • rugged construction CASE STYLE: LL561 Connectors Model SMA-Male ANNE-50+ Applications • • • • Price Qty. $9.95 ea. (1-9) +RoHS Compliant The +Suffix identifies RoHS Compliance. See our web site for RoHS Compliance methodologies and qualifications cellular communications satellite communications test set-up defense & radar Electrical Speciications TAMB=25°C Outline Drawing FREQUENCY (MHz) DC-18000 RETURN LOSS (dB) MIN. IMPEDANCE (OHMS) 50 POWER RATING* (W) DC-4 GHz 4-8 GHz 8-12 GHz 12-18 GHz 30 27 23 21 1.0 *At 50°C, derate linearly to 350mW at 100°C. Typical Performance Data Outline Dimensions ( inch mm ) A 0.58 14.73 B 0.37 9.40 C 0.35 8.89 wt grams 4.0 Frequency (MHz) Return Loss (dB) 100 596 1072 2024 2800 51.21 46.64 43.38 38.95 36.93 3400 4000 4800 6400 8000 35.82 35.20 34.92 35.97 40.29 10000 12000 14000 16000 18000 45.79 34.97 30.16 27.19 23.24 To order ANNE-50+ with 3½ length chain and end coupling with .130" diameter mtg. hole, use part no. ANNE-50CN+. Price is $11.95, Qty. (1-9) ANNE-50+ RETURN LOSS RETURN LOSS (D B) 70 60 50 40 30 20 10 0 3000 6000 9000 12000 *+,-.,/01 234Z 5 15000 18000 Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 350166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] REV. F M120264 ANNE-50+ ED-11192A 090526 HAND TM Coaxial Cable 50Ω 086 Model Series DC to 18 GHz The Big Deal CASE STYLE: KP1505-XX • Hand Formable XX= cable length in inches • Tight Bend Radius • Excellent Return Loss and Insertion Loss • Ideal for interconnect of assembled systems Product Overview The 086 Series Hand-Flex Coaxial Cables are ideal for interconnection of coaxial components or sub-systems. The construction includes a silver-plated copper-clad steel center conductor which maintains the shape after bending. The outer shield is copper braid, tin soaked, which minimizes signal leakage and at the same time flexible for easy bend. Dielectric is low loss PTFE. Connectors have passivated stainless-steel coupling nut over a gold plated connector body and gold plated, brass center conductor. Key FeaFeature Advantages Hand-Formable RF Cables The 086 Series Hand-Flex cables are hand formable making them ideal for use integrating coaxial components and sub-assemblies without the need for special cable-bending tools and alleviating the risk of damage during the bending process typical of semi-rigid coaxial cable assemblies. Tight Bend Radius Capable of only 6mm bend radius, the 086 Hand Flex series is able to make connections in tight spaces making these cables ideal for dense system integration Excellent Return loss Supporting typical return loss of 33 dB to 6 GHz and 21 dB to 18 GHz, the 086 Series Hand-Flex Cables are ideally suited for interconnecting a wide variety of RF components while minimizing VSWR ripple contribution due to mating cables & connectors. Good Power Handling Capability: • 211W at 0.5 GHz • 35W at 18 GHz Mini-Circuits 086 Cable series can support medium to high RF power levels enabling these cables to be used in the transmit path. NOTE: power rating is at sea-level altitudes. Built in Anti-torque nut Mini-Circuits 086 Series Hand Flex cables include an anti-torque feature to support the connector body during installation alleviating risk of stress to the connector/cable interface. Jacketed and Unjacketed options Standard 086 Series cables include a blue FEP insulator jacket reducing the risk of accidental shorting of DC power lines or active pins during installation and operation. Un-jacketed versions are available upon request. Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 350166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] HAND TM Coaxial Cable 50Ω 086 Model Series DC to 18 GHz The Big Deal CASE STYLE: KP1505-XX • Hand Formable XX= cable length in inches • Tight Bend Radius • Excellent Return Loss and Insertion Loss • Ideal for interconnect of assembled systems Product Overview The 086 Series Hand-Flex Coaxial Cables are ideal for interconnection of coaxial components or sub-systems. The construction includes a silver-plated copper-clad steel center conductor which maintains the shape after bending. The outer shield is copper braid, tin soaked, which minimizes signal leakage and at the same time flexible for easy bend. Dielectric is low loss PTFE. Connectors have passivated stainless-steel coupling nut over a gold plated connector body and gold plated, brass center conductor. Key Features Feature Advantages Hand-Formable RF Cables The 086 Series Hand-Flex cables are hand formable making them ideal for use integrating coaxial components and sub-assemblies without the need for special cable-bending tools and alleviating the risk of damage during the bending process typical of semi-rigid coaxial cable assemblies. Tight Bend Radius Capable of only 6mm bend radius, the 086 Hand Flex series is able to make connections in tight spaces making these cables ideal for dense system integration Excellent Return loss Supporting typical return loss of 33 dB to 6 GHz and 21 dB to 18 GHz, the 086 Series Hand-Flex Cables are ideally suited for interconnecting a wide variety of RF components while minimizing VSWR ripple contribution due to mating cables & connectors. Good Power Handling Capability: • 211W at 0.5 GHz • 35W at 18 GHz Mini-Circuits 086 Cable series can support medium to high RF power levels enabling these cables to be used in the transmit path. NOTE: power rating is at sea-level altitudes. Built in Anti-torque nut Mini-Circuits 086 Series Hand Flex cables include an anti-torque feature to support the connector body during installation alleviating risk of stress to the connector/cable interface. Jacketed and Unjacketed options Standard 086 Series cables include a blue FEP insulator jacket reducing the risk of accidental shorting of DC power lines or active pins during installation and operation. Un-jacketed versions are available upon request. Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 350166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] DC Pass Power Splitter/Combiner 4 Way-0° 50Ω 2000 to 6000 MHz Maximum Ratings Features Operating Temperature -55°C to 100°C Storage Temperature -55°C to 100°C Power Input (as a splitter) • • • • 10W max. Internal Dissipation DC Current ZN4PD1-63+ wide frequency band, 2000 to 6000 MHz low insertion loss, 0.7 dB typ. low amplitude unbalance 0.1 dB typ. low phase unbalance 1.0 deg. typ. CASE STYLE: UU846 Connectors Model Price SMA ZN4PD1-63-S+ $89.95 1W max. 1.0 A (250mA for each port) Applications Permanent damage may occur if any of these limits are exceeded. • high band PCS • UNII • ISM 802.11A Coaxial Connections SUM PORT 3 PORT 1 1 PORT 2 2 PORT 3 4 PORT 4 5 Qty. (1-9) Electrical Speciications FREQ. RANGE (MHz) ISOLATION (dB) fL-fU Typ. Min. INSERTION LOSS (dB) ABOVE 6.0 dB PHASE UNBALANCE (Degrees) AMPLITUDE UNBALANCE (dB) VSWR (:1) S Outline Drawing 2000-6000 26 17 Freq. (MHz) Total Loss1 (dB) OUT Typ. Max. Max. Max. Typ. Typ. 0.7 1.3 5 0.4 1.20 1.15 Typical Performance Data Phase VSWR VSWR VSWR VSWR VSWR S 1 2 3 4 Unbal. (deg.) Isolation (dB) Amp. Unbal. (dB) S-1 S-2 S-3 S-4 1-2 2-3 3-4 2000.00 2200.00 2400.00 2700.00 2900.00 6.48 6.43 6.46 6.54 6.71 6.48 6.43 6.46 6.53 6.70 6.49 6.44 6.47 6.54 6.71 6.45 6.39 6.42 6.48 6.65 0.03 0.05 0.05 0.06 0.06 23.63 23.43 21.86 21.17 22.08 37.44 35.91 32.38 29.48 28.54 23.98 23.81 22.07 21.21 22.04 0.64 0.59 0.66 0.71 0.70 1.29 1.05 1.11 1.14 1.15 1.25 1.17 1.12 1.20 1.24 1.25 1.18 1.14 1.21 1.24 1.24 1.17 1.13 1.19 1.23 1.25 1.16 1.12 1.18 1.21 3300.00 3700.00 4100.00 4500.00 4900.00 6.75 6.58 6.57 6.74 6.86 6.75 6.62 6.62 6.72 6.80 6.77 6.62 6.64 6.73 6.80 6.68 6.52 6.52 6.67 6.78 0.08 0.10 0.12 0.07 0.09 28.77 36.35 38.92 28.57 26.41 30.43 35.69 40.56 36.06 33.47 28.16 36.41 35.34 27.06 26.23 1.10 1.66 1.54 1.34 1.71 1.23 1.07 1.04 1.19 1.18 1.25 1.10 1.02 1.06 1.11 1.23 1.10 1.01 1.06 1.13 1.23 1.09 1.03 1.05 1.12 1.20 1.09 1.04 1.09 1.12 5300.00 5500.00 5700.00 5900.00 6000.00 7.07 7.00 6.90 6.85 6.89 7.04 7.05 6.98 6.91 6.92 7.05 7.05 6.98 6.91 6.90 6.96 6.88 6.76 6.72 6.74 0.11 0.17 0.21 0.19 0.18 24.11 21.50 20.24 19.87 19.46 29.43 27.37 25.26 23.47 22.75 23.55 20.85 19.67 19.64 19.42 1.54 1.58 1.68 1.36 1.20 1.21 1.28 1.30 1.25 1.20 1.11 1.12 1.16 1.19 1.20 1.11 1.12 1.16 1.17 1.17 1.11 1.14 1.19 1.21 1.21 1.08 1.09 1.13 1.18 1.20 1. Total Loss = Insertion Loss + 6dB splitter loss. ZN4PD1-63+ TOTAL LOSS ZN4PD1-63+ ISOLATION 45 J .33 8.38 K .50 12.70 D .125 3.18 E 3.375 85.73 L M .400 4.100 10.16 104.14 F --- G .125 3.18 wt grams 288 6.9 6.7 6.5 6.3 2000 2500 3000 3500 S-1 (dB) S-3 (dB) 4000 5000 4500 40 35 30 1-2 (dB) 25 2-3 (dB) 20 5500 6000 15 2000 3-4 (dB) 2500 FREQUENCY (MHz) ZN4PD1-63+ VSWR 3000 3500 4000 4500 5000 5500 6000 FREQUENCY (MHz) 1.5 1.4 VSWR (:1) H --- C .65 16.51 ISOLATION (dB) Outline Dimensions ( inch mm ) A B 3.50 4.50 88.90 114.30 TOTAL LOSS (dB) 7.1 #S-VSWR #1-VSWR electrical schematic #3-VSWR DC Through 1.3 RF+DC RF+DC 1.2 RF+DC 1.1 RF+DC RF+DC 1.0 2000 2500 3000 3500 4000 4500 5000 5500 6000 FREQUENCY (MHz) Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 350166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] REV. B M147045 ZN4PD1-63+ ED-12277/1 HY/IZ/CP/AM 140625 DC Pass Power Splitter/Combiner 8 Way-0° 50Ω ZN8PD-642W+ 1800 to 6400 MHz Maximum Ratings HT-Series Tight Spot SMA Wrench From $24.95 Features Operating Temperature -55°C to 100°C Storage Temperature -55°C to 100°C Power Input (as a splitter) • wideband, 1800 to 6400 MHz • low insertion loss, 1.5 dB typ. • low amplitude unbalance, 0.2 dB typ. • excellent output VSWR, 1.15:1 typ. • DC PASS from sum port to output ports 10W max. Internal Dissipation 0.875W max. CASE STYLE: UU1676 Connectors SMA The +Suffix identifies RoHS Compliance. See our web site for RoHS Compliance methodologies and qualifications Applications SUM PORT • high band PCS • UNII • WIMAX • WiFi • bluetooth S(COM) PORT 1,2,3,.....,8 Qty. (1-9) +RoHS Compliant Permanent damage may occur if any of these limits are exceeded. Coaxial Connections Model Price ZN8PD-642W-S+ $169.95 1,2,3.....,8 Outline Drawing Electrical Speciications at 25°C Parameter Frequency (MHz) Min. 1800-3200 3200-6400 1800-3200 3200-6400 1800-3200 3200-6400 1800-3200 3200-6400 1800-3200 3200-6400 1800-3200 3200-6400 1800 — — 15 18 — — — — — — — — Frequency Range Insertion Loss (above theoretical 9.0 dB) Isolation Phase Unbalance Amplitude Unbalance VSWR (Port S) VSWR (Port 1-8) Typ. Max. Unit MHz 0.9 1.5 20 25 2 5 0.15 0.30 1.4 1.2 1.15 1.15 6400 1.4 2.3 — — 8 12 0.5 0.7 — — — — dB dB Degree dB :1 :1 1. Over -55°C to +55°C. Derate linearly to 20% of rating at 100°C Outline Dimensions ( inch mm ) A 6.60 167.64 B 3.28 83.31 C .75 19.05 H 3.30 83.82 J .38 9.65 K .500 12.70 D E .150 6.45 3.81 163.83 L 1.000 25.4 M 1.500 38.1 Typical Performance Data F 1.64 41.66 G .144 3.66 N wt 0.550 grams 13.97 360 electrical schematic Total Loss1 (dB) Freq. (MHz) 1800.00 2000.00 2200.00 2400.00 2600.00 3000.00 3200.00 3400.00 3600.00 4000.00 4200.00 4600.00 5000.00 6000.00 6400.00 S-1 S-2 S-3 S-4 S-6 S-8 Amp. Unb. (dB) 9.72 9.84 9.79 9.73 9.71 9.82 9.87 9.91 9.97 10.13 10.06 10.22 10.14 10.53 10.43 9.67 9.80 9.77 9.74 9.75 9.87 9.90 9.91 9.97 10.19 10.14 10.27 10.17 10.56 10.46 9.66 9.83 9.74 9.70 9.73 9.88 9.90 9.90 9.95 10.24 10.15 10.19 10.16 10.49 10.48 9.64 9.81 9.72 9.66 9.71 9.84 9.86 9.88 9.96 10.28 10.13 10.13 10.12 10.39 10.49 9.77 9.92 9.81 9.80 9.83 9.99 9.99 10.03 10.03 10.34 10.23 10.30 10.35 10.78 10.59 9.70 9.79 9.74 9.71 9.71 9.86 9.87 9.90 9.90 10.11 10.05 10.22 10.12 10.65 10.42 0.16 0.13 0.14 0.15 0.12 0.17 0.13 0.16 0.13 0.28 0.20 0.18 0.24 0.38 0.23 Isolation (dB) 1-2 1-3 3-4 5-6 25.78 20.29 18.45 20.16 21.93 23.46 30.75 45.47 28.90 21.81 26.07 25.17 29.89 29.32 21.01 28.68 33.24 40.43 29.69 26.40 30.50 38.89 32.14 28.38 29.25 30.25 27.39 30.66 27.33 27.28 26.43 20.60 18.75 19.86 21.99 23.32 28.89 35.75 27.91 20.71 24.95 23.49 32.53 29.76 20.87 24.46 19.95 18.57 19.97 22.22 23.43 29.31 37.68 28.25 20.89 23.54 25.46 29.80 29.12 21.95 Phase Unb. (deg.) VSWR VSWR VSWR S 1 8 1.73 1.89 1.44 1.49 1.40 1.64 2.00 2.11 2.21 2.25 2.48 3.48 4.17 5.23 5.65 1.39 1.50 1.39 1.19 1.12 1.20 1.19 1.26 1.29 1.22 1.28 1.24 1.11 1.21 1.11 1.18 1.13 1.03 1.09 1.06 1.12 1.04 1.05 1.01 1.21 1.13 1.14 1.16 1.17 1.22 1.19 1.15 1.09 1.07 1.04 1.11 1.07 1.02 1.03 1.12 1.07 1.05 1.11 1.15 1.11 1. Total Loss = Insertion Loss + 9dB theoretical splitter loss. ZN8PD-642W+ TOTAL LOSS 1.8 60 11.0 50 ISOLATION (dB) S-1(dB) 10.6 S-8(dB) 10.4 10.2 10.0 9.8 40 30 9.4 1500 2500 3500 4500 FREQUENCY (MHz) 5500 6500 0 1500 1.4 1.2 20 1-2(dB) 10 9.6 #S-VSWR #1-VSWR 1.6 VSWR 10.8 TOTAL LOSS (dB) ZN8PD-642W+ VSWR ZN8PD-642W+ ISOLATION 2-4(dB) 2500 3500 4500 FREQUENCY (MHz) 1.0 1500 5500 6500 2500 3500 4500 5500 6500 FREQUENCY (MHz) Notes A. Performance and quality attributes and conditions not expressly stated in this specification document are intended to be excluded and do not form a part of this specification document. B. Electrical specifications and performance data contained in this specification document are based on Mini-Circuit’s applicable established test performance criteria and measurement instructions. C. The parts covered by this specification document are subject to Mini-Circuits standard limited warranty and terms and conditions (collectively, “Standard Terms”); Purchasers of this part are entitled to the rights and benefits contained therein. For a full statement of the Standard Terms and the exclusive rights and remedies thereunder, please visit Mini-Circuits’ website at www.minicircuits.com/MCLStore/terms.jsp Mini-Circuits ® www.minicircuits.com P.O. Box 35166, Brooklyn, NY 11235-0003 (718) 934-4500 [email protected] REV. OR M134683 ZN8PD-642W+ ED-14604/4 SZ/CP/AM 130913 74 C Mini Circuits datasheets Upphovsrätt Detta dokument hålls tillgängligt på Internet — eller dess framtida ersättare — under 25 år från publiceringsdatum under förutsättning att inga extraordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning av dokumentet kräver upphovsmannens medgivande. För att garantera äktheten, säkerheten och tillgängligheten finns det lösningar av teknisk och administrativ art. 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All other uses of the document are conditional on the consent of the copyright owner. The publisher has taken technical and administrative measures to assure authenticity, security and accessibility. According to intellectual property law the author has the right to be mentioned when his/her work is accessed as described above and to be protected against infringement. For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its www home page: http://www.ep.liu.se/ © Jacob Carlsson