Download Isolated WiFi Environments Jacob Carlsson LiU-ITN-TEK-A-15/003-SE 2015-02-04

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
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© 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 . . . . . . . . .
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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 . . . . . . . . .
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5
5
7
7
12
13
14
3 Wired setup
3.1 Components . . . . . . . . . . . .
3.2 Attenuation between components
3.3 Throughput . . . . . . . . . . . .
3.4 Reliability . . . . . . . . . . . . .
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19
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4 Encapsulation
4.1 Faraday cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 RF-shielding enclosures . . . . . . . . . . . . . . . . . . . . . . . . .
23
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25
5 Result
5.1 Wired setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
27
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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
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39
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7 Conclusion
7.1 Wired setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3 Final solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
43
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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 . . . . . . . . . . . . . . . . . . . . . . .
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46
Bibliography
47
A Considered methods
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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
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• 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
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