Download CELLULAR OVER BROADBAND NETWORKS

CELLULAR OVER
BROADBAND NETWORKS
Khurshid Hafiz
Masters Student
Department of Electrical
& Computer Engineering
April 11, 2007
Overview
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Background
Broadband Networks
Features
Broadband and Cellular Networks
Communication Principles
Model of Broadband Wireless Networks
Challenges of Cellular over Broadband
Proposed Solutions
Examples
Conclusion
References
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Background
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Growing wireless multimedia applications are demanding
high data rates and varying QoS requirements.
To provide this at affordable price to customers, service
providers are looking for systems that require low deployment
cost and which can accommodate as many high data rates as
possible.
Therefore there is a need to look into alternate wireless
network architectures other than the traditional cellular
networks to achieve the above objectives.
With the emerging ATM broadband networks and next
generation wireless networks, there will be a call for
connectivity between these networks.
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Background
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It is desirable to have a single network for providing all
these communication services in order to achieve the
economy of sharing.
This economy motivates the general idea of an integrated
services network.
Integration avoids the need for many overlaying networks,
which complicate network management and reduce the
flexibility in the introduction and evolution of services.
This integration is made possible with the advances in
broadband technologies and high speed information
processing
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Background
TABLE 1
TYPES OF SERVICE, DATA RATE DEMANDS
Service
Data Rate
Voice
19.2 Kbps
Web
400 Kbps
Photo Message
1 Mbps
Interactive Video
1 Mbps
Streaming Video
2 Mbps
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Broadband Networks
The types of traffic supported by a broadband network can
be classified according to three characteristics.
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Bandwidth: Is the amount of network capacity required to
support a connection.
 Latency: Is the amount of delay associated with a
connection. Requesting low latency in the Quality of
Service (QoS) profile means that the packets need to
travel quickly from one point in the network to another.
 Packet-delay variation: Is the range of delays experienced
by each group of associated packets. Low packet-delay
variation means a group of packets must travel through the
network without getting too far apart from one another
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Features
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Modern communication services requires broadband network
and from economical point of view utilizing a single network
for multiple services is an advantage.
However understanding and controlling traffic in this situation
is essential for quality of service.
These type of telecommunication networks should have the
following characteristics:
 Broadband
 Multimedia
 Multi-point
 Multi-rate
 Multi-services
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Features
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Multimedia: A multi-media call may communicate audio,
data, still images, or full-motion video, or any combination
of these media. Each medium has different demands for
communication qualities, such as:
 bandwidth requirement,
 signal latency within the network, and
 signal fidelity upon delivery by the network
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Multi-point : A multi-point call involves the setup of
connections among more than two people. These
connections can be multi-media. They can be one way or
two way communications. These connections may be
reconfigured many times within the duration of a call.
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Features
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Multi-rate: A multi-rate service network is one which
allocates transmission capacity flexibly to connections. A
multi-media network has to support a broad range of bitrates demanded by connections, not only because there
are many communication media, but also because a
communication medium may be encoded by algorithms
with different bit-rates.
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Multi-services: Economical implementation for a diversity
of services e.g voice, data, video etc.
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Features
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The Broadband Integrated Services Digital Network (B-ISDN)
or ADSL provides these characteristics to a network.
Asynchronous Transfer Mode (ATM) is a target
technology for meeting these requirements and is widely
deployed as a broadband network
Next generation communication services will require to
provide multimedia services over large distances through a
broadband wireless infrastructure.
This trend pushes the technological emergence of a unified
wireless network technology, such as wireless ATM.
Today's systems such as Global System for Mobile
communications (GSM) and G4 can also provide these type
of services.
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Broadband and Cellular networks
 The provision of wireless access broadband networks,
carrying multimedia traffic introduces a set of challenges due
to two major differences between them
 Link characteristics
 Mobility
 Broadband networks transmission are characterized by high
transmission rates and low error rates as compared to
wireless network
 Wireless cellular networks are affected by shadowing and
multifading resulting in bit error rate varying in time and spatial
dependencies
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Communication Principals
Fig. 1: Basic Mobile Telephone Service Network
Fig. 2: Fixed Wireless Access
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Communication Principals
Fig. 3: Structure of a Cellular System
In a typical cellular system,
the base stations (BS),
at the center of each cell
are connected to the base
station controllers (BSC),
which are in turn are
connected to the mobile
switching centers (MSC)
and eventually to the
public switched network
(PSTN).
Home Location Register (HLR) and Visiting Location Register
(VLR) keep track of the users on the move
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Model of Broadband Wireless Network
The communication
network integrates
wireless and wireline
networks
Employs wireless
media in the local
environment in order
to satisfy the demand
for mobility and
tetherless access
Fig. 4: Example of Broadband Wireless System
And will also employ wireline network to provide high
speed backbone
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Model of Broadband Wireless Network
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In typical wireless systems, as in Fig. 4, the area that is
covered may be divided into cells
In each cell is a base station that is connected with the
wireline network and the mobiles as shown in the figure.
The base stations communicate with the mobiles on one hand
and with other base stations through the wireline networking
infrastructure on the other.
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Challenges of Cellular over Broadband
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In the digital age, voice, data, image and video are converging
into bit streams.
This trend creates a need for high-capacity networks to carry
traffic as diverse as phone calls, data look-up, pictures,
entertainment and emergency alerts at low cost and without
congestion.
Different types of applications place different demands on a
network
The implementation of an efficient protocol becomes extremely
important and challenging when the wireless network and
broadband transmission system is expected to provide a
guaranteed Quality of Service (QoS) and also must make full
use of the available channel resources.
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Challenges of Cellular over Broadband
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Introduction of ATM technology will be complicated by the fact
that it is designed to support connections between fixed end
points involving switches and links.
Due to the user mobility in a wireless network, the issue of
maintaining an end-to-end ATM connection between a mobile
in the wireless network and a fixed user in ATM broadband
network arises due to high rate of handoffs.
A scheme for interconnection should be able to maintain an
end-to-end connection without causing a significant overhead
to the ATM network call processor.
When the ATM technology was designed, it was implicitly
assumed that only fixed points (users) would be involved in a
virtual circuit/path and thus packet integrity would be
preserved as ATM packets travel over a virtual connection.
However, a scheme for interconnection must guarantee that
packets for a given connection, even under a high rate of
handoffs, will be delivered in sequence.
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Proposed Solutions
Fig. 5: A Wireless Access Broadband Network
A wireless station M communicating with
A fixed station S using base station B.
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Proposed Solutions
P
Fig 6. A Wireless Access Broadband Network
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Base stations are connected directly to an ATM switch port using an interface unit
or multiple stations are connected to a switch port.
Suppose a connection exists between a fixed user P and a mobile Q using
switches A, B and C and the base station of cell X
If mobile Q moves to cell Y, this handoff will cause only one mapping change
as only switch C will need to change the input-output mapping to maintain the endto-end connection between P and Q. However, if mobile Q moves to cell Z, then
switch B, C, and D will need to change the input-output mapping. Therefore this
handoff will cause total three mapping changes
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Examples of Broadband
T-Mobile FLASH-OFDM
Mobile Broadband Network,
Slovakia.
The network is Europe's
first commercial mobile
broadband service.
Uses Fast, Low-latency
Access with Seamless
Handoff – Orthogonal
Frequency Division
Multiplexing (FLASHOFDM) network.
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Examples of Broadband
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FLASH-OFDM is a new signal processing scheme that can
support high data rates at very low packet and delay losses,
also known as latencies, over a distributed all-IP wireless
network. The low-latency enables real-time mobile interactive
and multimedia applications. It is also able to offer higher
quality wireless service and better cost effectiveness than
current wireless data technologies.
Cellular broadband is available from most of the major
carriers now, including Verizon, Sprint, T-Mobile and Cingular.
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Conclusion
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Integration of cellular wireless links into broadband networks
necessitates provision of reliable radio links and call control
methodologies that take mobility into account for providing
seamless interconnection.
Although new technologies have improved the availability of
capacity, user requirements for bandwidth have been
increasing fast. Till now, individual users require typically
about 2-3 Mb/s of bandwidth and enterprises require about
100-1000 Mb/s.
Bandwidth is in fact still a concern.
It is desirable to introduce the ATM technology in the wireless
networks also.
While popular "Wi-Fi hot spots" offer public wireless
broadband in coffee shops and airports, this service would
make a laptop as mobile as a cell phone.
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References
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[2] Marshall, A.; Martin, T.; You, J., “Performance Analysis of a MAC Protocol
for Multiple Services in Cellular Broadband Networks”, Wireless
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[3] Shengming Jiang; Tsang, D.H.K.; Gupta, S., “On Architectures for
Broadband Wireless Systems”, IEEE Communications Magazine, Volume
35, Issue 10, Oct. 1997 Page(s):132 – 140
[4] Lazar, A.A.; Pacifici, G., “Control of Resources in Broadband Networks with
Quality of Service Guarantees”, IEEE Communications Magazine, Volume
29, Issue 10, Oct. 1991 Page(s):66 – 73
[5] Vecchi, M.P., “Broadband Networks and Services: Architecture and Control”,
IEEE Communications Magazine,Volume 33, Issue 8, Aug. 1995
Page(s):24 – 32
[6] Kos, T.; Sprljan, N.; Zovko-Cihlar, B., “Comparison of Broadband Network
Technologies”, Computer as a Tool, The IEEE Region 8, EUROCON 2003.
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References
[7] Syed, I.; Ahmed, M.H.; Yanikomeroglu, H.; Mahmoud, S., “Impact of Multiple
Frequency Channels Usage on the Performance of TDMA-based Broadband
Fixed Cellular Multihop Networks”, 2004 IEEE Wireless Communications and
Networking Conference, 2004, Volume 2, 21-25 March 2004 Page(s):1105 1108 Vol.2
[8] Santhi, K.R.; Srivastava, V.K.; SenthilKumaran, G.; Butare, A, “Goals of True
Broadband's Wireless Next Wave (4G-5G)”, 2003 IEEE 58th Vehicular
Technology Conference, 2003, Volume 4, 6-9 Oct. 2003 page(s):2317 2321 Vol.4
[9] Ariyavisitakul, S.L.; Durant, G.M., “A Broadband Wireless Packet Technique
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[10] C. K. Toh, The Wireless Network Evolution, Prentice Hall PTR,
http://www.phptr.com, accessed on March 22, 2007
[11] Nie Wuchao, Build Operable, Manageable and Profitable Broadband
Telecom Network, Issue 12, Huawei Technologies Co., Ltd.
http://www.huawei.com, accessed on March 22, 2007.
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THANK YOU
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