Introduction To Cellular Networks

NDI Communications - Engineering & Training
Introduction to Cellular NetworksIntroduction to Cellular Networks
Part 1Part 1 –– Traditional NetworksTraditional Networks

© NDI Communications ©
Lesson Content
Introduction
The network evolution
Early (2.0-2.5G) cellular networks
Broadband (3.0-3.75) Cellular Networks
Commercial and economical issues

Wireless and Cellular Networks - History
In 1905, Guglielmo Marconi invented the first
Radio application for Naval requirements
In 1912, with the drowning of the Titanic, Radio
communications became essential
In 1930, the First mobile transmitter was
developed. First – Simplex communications.

In 1935, FM – Frequency Modulation
developed. Later used in WW2 by the US
In 1942, a Patent for Frequency Hoping was
registered by actress Hedy Lamarr and
composer George Antheil. Later developed to
CDMA. They called it “Secret Communication
System ”
During the years 1946-1968, wireless
communications developed for government
services – Police, Fire departments etc…

1979 in Tokyo, Japan. Later in the early 80’s
in the US and Europe – the first real mobile
hone, including handoff.
In the early-mid 80’s, various technologies
came, like WLL, LMDS, and Wireless LAN.
In the mid-late 90’s, development of 2.0G+
cellular networks, along with the emerging of
wireless data networks.
Since the early 2000’s, fast cellular and
wireless services, along with advanced, IP-
Based services

What do we have today ?
Cellular technologies
Started 1.0G, analog communications
Today (2009), 3.5G moving to 4.0G (LTE and LTE-Advanced)
technology
Wireless technologies:
Wireless LAN (WiFi), for urban areas, mostly private networks,
moving to mobility
Fixed WiMAX for high bandwidth, SP networks

Where is it in the Network?
First Mile Access
DSLAM
CMTV
Wireless
Cellular
FO
Technologies
Service Networks
Internet
Voice
VideoVideo
AOL
Earthlink
Yahoo
PSTN
Skype
Vonage
Direct TV
Content Aggregator
Core/Switching
Network

Some Wireless Principles – Radio
Communications
In wireless / mobile communications, the principle is to get the
maximum capacity from the air, or what called – the air interface.
For this purpose, we use the following techniques:
Frequency bands – that we are allowed to use (Government Licenses)
Modulation – that carry the information over the radio waves
Multiplexing – that shared the air interface between different users.

What is it All About?
How much bps can we get from every Hz ???
(The Shannon’s Theorem)
C = W * log2 (1 + S/N)
Channel
Capacity
[Bits/sec] Signal
Bandwidth
[Hz]
Signal to Noise
Ratio
[Number]
Claude E.
Shannon

How it works – The beginning
Traditional mobile service was structured in a fashion similar to
television broadcasting
One very powerful
transmitter located at
the highest spot in an
area would broadcast
in a radius of up to
50Km.

And Then ….
With one antenna – limited cover and number of users
Therefore – split into many low power transmitters

The Solution - Cells
Frequency reuse
Different color –
different frequency
In the example N (Reuse factor) =7

Practical Frequency reuse – Cell Splitting
We start with Macro-Cells
Rural areas
Then Micro-Cells
More crowded rural areas
Then Pico-Cells
Urban area
C
D
E
G
F
A
Macro cells
B
C
D
E
G
F
AMicro cells
B
C
D
E
G
F
B
A
Pico cells

Moving Between Cells
Mobile phones moves between cells
The handset should not be disconnected
Base
Station
F2
Base
Station
F1

The Solution - The Handover Process
RSSI RSSI RSSI
FRQ A FRQ CFRQ B
Handover
Happens
Here
RSSI - Received Signal Strength Indicator
Handover
Happens
Here

Access Methods
The Major Air-Interface Methods are:
Frequency Division Multiple Access (FDMA)
Time Division Multiple Access (TDMA)
Code Division Multiple Access (CDMA)
Frequency
Time
Code
FDMA
Frequency
Tim
e
Code
TDMA
Frequency
Time
Code
CDMA

The Cellular Network Structure
Cell phones
The UserThe UserThe UserThe User
The Radio
Network
The AccessThe AccessThe AccessThe Access
NetworkNetworkNetworkNetwork
Circuit Switching
Packet Switching
The Core
Network
The SwitchingThe SwitchingThe SwitchingThe Switching
NetworkNetworkNetworkNetwork
Mobile
Internet
Intelligent Network
Advanced Services
Intelligent
Network
The ServicesThe ServicesThe ServicesThe Services
FO Cables
FO Cables
MW
Air
Interface

Lesson Content
Introduction
The network evolution
Early (2.0-2.5G) cellular networks
Broadband (3.0-3.75) Cellular Networks
Commercial and economical issues

Early Technologies – 1G to Early 3G
Evolution
NMT GSM
TACS
cdmaOne
(ANSI-95)
1990 1995 2000 2005
GRPS (2,5G) and
EDGE (2.75G)
[Upto 384Kbps]
cdmaOne
(ANSI-95-B)
[64-115]
AMPS
D-AMPS
(TDMA)
ANSI-136
IS-136
(ANSI-136-A/B)
[Upto 64Kbps]
1G 2G 2.5G
3GPP
WCDMA R.99
[2Mbps]
Cdma2000
(1.25/3.75MHz)
[307-2048Kbps]
Early 3.0G
TDMA-EDGE
(IS-136HS)
[Upto 384Kbps]

Wireless and Mobile 3G Technologies
Evolution
2005 2006 2007 2008 2009 2010
IEEE 802.16-2004/
ETSI HiperMAN
OFDM
3GPP
HSDPA
R5
3GPP
HSUPA
R6
3GPP MIMO/
HSPA+ R7
SAE/LTE R8
3GPP2
1xEVDV
RevA
3GPP2
1xEVDO
RevB
IEEE 802.16e-2005/
ETSI HiperMAN
SISO/OFDMA
IEEE 802.16e-2005/ETSI HiperMAN
MIMO/Beamforming/OFDMA
3G to 4G
WiMAX
3GPP
WCDMA
R.99
3GPP2
1xEVDO
Rev0

Cellular Standards (1.0-3.0G) - Summary
CDMA2000 1xEV-DO (IS-856)3GPP2
UMTS (UTRAN), WCDMA-FDD, WCDMA-TDD, UTRA-
TDD LCR (TD-SCDMA)
3GPP3G (IMT-2000)
WiDENOther
CDMA2000 1xRTT (IS-2000)Cdma/3GPP2
HSCSD, GPRS, EDGE/EGPRSGSM/3GPP2G transitional
(2.5G, 2.75G)
CDPD, iDEN, PDC, PHSOther
CdmaOne (IS-95)Cdma/3GPP2
GSM, CSDGSM/3GPP2G
NMT, Hicap, Mobitex, DataTACOther
AMPS, TACS, ETACSAMPS family1G
TechnologiesFamily

Cellular Standards (3.0G+) - Summary
IEEE 802.16m (WiMAX)Other
LTE AdvancedCdma/3GPP2
LTE AdvancedGSM/3GPP4G (IMT-
Advanced)
Mobile WiMAX (IEEE 802.16e-2005) — Flash-OFDM,
IEEE 802.20
Other
EV-DO Rev. A, EV-DO Rev. BCdma/3GPP2
HSDPA, HSUPA, HSPA+, LTE (E-UTRAN)GSM/3GPP3G transitional
(3.5G, 3.75G,
3.9G)
TechnologiesFamily

Wireless and Mobile Communications –
Cellular Networks
2010200320011985 1992-2000
1.0G
Analog
Systems
Speech
Only
Voice
No Data
2.0G
TDMA/GSM/C
DMA
Speech
SMS
WAP
Voice
30-40Kbps
Data
2.5G
GPRS/1XRTT
Speech and
packet based
Data
Services
Voice
100-200Kbps
Data
3.0G-3.5G
UMTS/CDMA
2000
HSDPA/HSUPA
1xEVDO/DV
Video Streaming,
Video conference,
High speed Packet
Data
Voice
1-5Mbps
Data
4.0G
LTE
Advanced
100’s Mbps
data
transfer
Voice
5-100Mbps
Data
Voice Over IP

The 2.0G Networks
The critical problem in 1.0G was capacity. The main requirement was
to increase it
These requirements brought several new technologies:
The general characteristics of Time Division Multiple Access (TDMA)
Global System for Mobile Communications (GSM)
CDMA - Code Division Multiple Access
Promise to significantly increase the efficiency of cellular telephone
systems to allow a greater number of simultaneous conversations.

The GSM Network
GSM, or Global System for Mobile Communications, is a second
generation technology.
The focus in GSM was to support roaming throughout Europe.
An ETSI standard. In use all around the world.
GSM is not only an air interface standard, but includes the entire
network.
Of the numerous individual standards that define an entire GSM
network, only a small portion deal directly with the air interface. That
air interface was standardized to be TDMA.

The GSM Network
BSC
BTS
BTS
Mobile
Station
Access Network:
Base Station Subsystem
HLR VLR EIR AuC
MSC
PSTN
Core Network:
GSM CS network
SS7
GSM Interfaces Parallel North American
Technology – cdma1

GSM Air Interface
FDMA:
124 channels of 200KHz
Total 25MHz Uplink
25MHz Downlink
TDMA:
8*TS for channel

GPRS and EDGE for Early Data Applications
The two key benefits of GPRS were:
Better use of radio and network resources
Completely transparent IP support
GPRS optimises the use of network and radio resources. It uses radio
resources only when there is data to be sent or received.
GPRS have added two major components, that are still used in cellular data
networks:
GGSN (Gateway GPRS Support Node) {DHCP and FW} – for filtering and firewall, Charge
collections and PDN access
SGSN (Serving GPRS Support Node) {Switch} – for Authentication, Authorisation,
Encryption, Compression, Mobility management, Charge collection, BSS interface
EDGE was a Pre-3.0G network, that improved data-rate by better modulation
techniques

The Cellular Network Structure – 2.0G-2.5G
BSC
PCU
Packet
Network
Packet
Network
SGSN
IP netIP net
GGSN
Data Network
Data Network
TRAU MSC
PSTNPSTN
Circuit Switching
Packet Switching
VLR
BTS
Mobile
Device
BTS
HLR

3.0G - Introduction
Started as IMT–2000 (International Mobile Telecommunications-2000):
Used worldwide
Used for all mobile applications
Support both packet-switched (PS) and circuit-switched (CS) data
transmission
Offer high data rates up to 2 Mbps (depending on mobility/velocity)
Offer high spectrum efficiency

The IMT-2000 Vision
IMT-SC* Single Carrier (UWC-136): EDGE
GSM evolution (TDMA); 200 KHz channels; sometimes called “2.75G”
IMT-MC* Multi Carrier CDMA: CDMA2000
Evolution of IS-95 CDMA, i.e. cdmaOne
Now – 3GPP2
IMT-DS* Direct Spread CDMA: W-CDMA
Evolution of GSM - UMTS
Now - 3GPP
IMT-TC** Time Code CDMA
Originally from 3GPP; UTRAN TDD
Came from China; TD-SCDMA
IMT-FT** FDMA/TDMA (DECT legacy)

A Few Words About 3G+ Standards
3GPP
(W-CDMA)
ETSI
ARIB
ATIS
CCSA
TTA
TTC
3GPP2
(CDMA2000)
TIA
ITU-T
IMT
2000

3.0G – UMTS / W-CDMA
UMTS - Universal Mobile Telecommunications System
Spread Spectrum CDMA radio technology
All sites transmits in the same frequencies
They differ by codes
High capacity for voice and data applications
Standardized by 3GPP

Basic 3.0G UMTS Cellular Network
Architecture
RNC
3G
handset Node B
UMTS Access Network
Packet
Switched
Network
SGSN

HSPA - HSDPA / HSUPA / HSPA+
High Speed Packet Access (HSPA) is a generic term adopted by the UMTS
Forum to refer to improvements in the UMTS Radio Interface
HSPA refers to both the improvements made in the UMTS downlink, often
referred to as High Speed Downlink Packet Access (HSDPA) and the
improvements made in the uplink, often referred to as High Speed Uplink
Packet Access (HSUPA)
HSPA Releases:
Release 5 - HSDPA (High Speed Downlink Packet Access)
Downlink – 14.4Mbps, Uplink – 384Kbps
Release 6 - HSUPA (High Speed Uplink Packet Access)
Downlink – 14.4Mbps, Uplink - 5.76Mbps
Release 7 - HSPA+
Downlink – 56.0Mbps, Uplink - 22.0Mbps

HSDPA - High Speed Downlink Packet Access
Technology changes:
A new common High Speed Downlink Shared Channel (HS-DSCH) which
can be simultaneously shared by multiple users
The usage of multiple codes with Spreading Factor 16 (SF-16) for the
downlink transfer of data
The use of a shorter Transmission Time Interval (TTI) of 2ms, which
enables higher speed transmission in the physical layer,
The use of fast scheduling
The use of Adaptive Modulation and Coding (AMC),
The use of fast retransmission based on fast Hybrid Automatic Response
reQuest (HARQ) techniques.
Bandwidth:
Downlink – 14.4Mbps, Uplink – 384Kbps

HSUPA - High Speed Uplink Packet Access
Similarly to HSDPA in the downlink, HSUPA defines a new radio
interface for the uplink communication. The overall goal is to improve
the coverage and throughput as well as to reduce the delay of the
uplink dedicated transport channels.
Technology changes:
A new dedicated uplink channel,
Introduction of H-ARQ,
Fast Node B scheduling.
Bandwidth:
Downlink – 14.4Mbps, Uplink – 5.76Mbps

HSPA+ (Evolved HSPA)
HSPA+ provides HSPA data rates up to 56 Mbit/s on the
downlink and 22 Mbit/s on the uplink through the use of:
2*2 MIMO - Multiple-Input Multiple Output - multiple-antenna
technique
Higher order modulation (64QAM)
Bandwidth:
Data rates of up to 56Mbit/s (D) and 22Mbit/s (U) represent
theoretical peak sector speeds.
The actual speed for a user is lower.
Future revisions of HSPA+ support up to 168 Mbit/s using multiple
carriers.

HSPA+ and MIMO technology
MIMO on CDMA based systems acts like virtual sectors to give extra
capacity closer to the mast.

HSPA+ All-IP Network Architecture
HSPA+ also introduces an optional all-IP architecture for the
network where base stations are directly connected to IP based
backhaul and then to the ISP's edge routers.
The technology also delivers significant battery life
improvements and dramatically quicker wake-from-idle time -
delivering a true always-on connection.
HSPA+ should not be confused with LTE, which uses a new air
interface.

Radio Capacity Evolution

Delay Improvements in HSPA Technologies

Part 2Part 2 –– LTELTE –– Long Term EvolutionLong Term Evolution

Lesson Content
Introduction and Objectives
LTE Network Architecture
LTE Radio Interface
Innovations ad applications
Services and Implementation

3GPP Evolution
3GPP Evaluation
Release 99 (2000) - UMTS/WCDMA
Release 5 (2002) – HSDPA, multiple codes in Downlink channel
Release 6 (2005) - HSUPA, MBMS (Innovations ad applications)
Release 7 (2007) – HSPA+/E-HSPA - DL MIMO, IMS (IP Multimedia Subsystem),
optimized real-time services (VoIP, gaming, push-to-talk), early All-IP Network
implementation
Release 8 (2009) - LTE (Long Term Evolution), new air-interface and network
architecture (SAE)
Release 9 (2010) - minor changes to release 8
Release 10 (2011+) – LTE Advanced
Long Term Evolution (LTE)
3GPP work on the Evolution of the 3G Mobile System started in November 2004
Currently, standardization in progress in the form of Rel-8
First deployments – late 2009 (Telia-Sonera)

LTE – Long Term Evolution - Objectives
Higher performance
100 Mbit/s peak downlink, 50 Mbit/s peak uplink
Reduced latency (to 10 ms) for better user experience
Scalable bandwidth up to 20 MHz
Backwards compatible
Works with GSM/EDGE/UMTS systems
Utilizes existing 2G and 3G spectrum and new spectrum
Supports hand-over and roaming to existing mobile networks
Reduced CAPEX/OPEX via simple architecture
Reuse of existing sites and multi-vendor sourcing
Wide application
TDD (unpaired) and FDD (paired) spectrum modes
Mobility up to 350kph
Large range of terminals (phones and PCs to cameras)Co-existence with legacy standards – GSM
and W-CDMA-based UMTS and cdmaOne or CDMA2000) networks
Full support for IP services - Mobile TV, Radio and television broadcasts and more
All-IP network - radio interface is purely optimized for IP transmissions not having to
support ISDN traffic – packet based network only

LTE Performance Requirements
Data Rate:
Instantaneous downlink peak data rate of 100Mbit/s in a 20MHz downlink
spectrum (i.e. 5 bit/s/Hz)
Instantaneous uplink peak data rate of 50Mbit/s in a 20MHz uplink
spectrum (i.e. 2.5 bit/s/Hz)
Cell range
5 km - optimal size
30km sizes with reasonable performance
Up to 100 km cell sizes supported with acceptable performance
Cell capacity
Up to 200 active users per cell (5 MHz) (i.e., 200 active data clients)

Technical Details of LTE
Multiple access scheme
Downlink: FDMA (also called DMT)
Uplink: Single Carrier FDMA (SC-FDMA)
Adaptive modulation and coding
DL modulations: QPSK, 16QAM, and 64QAM
UL modulations: QPSK and 16QAM
Rel-6 Turbo code: Coding rate of 1/3, two 8-state constituent encoders, and a
contention- free internal interleaver.
Bandwidth scalability for efficient operation in differently sized allocated
spectrum bands
Possible support for operating as single frequency network (SFN) to support
MBMS

LTE Network Architecture

System Architecture Evolution (SAE)
System Architecture Evolution (SAE) is the core network architecture of
3GPP's future LTE wireless communication standard.
SAE is the evolution of the GPRS Core Network, with some differences.
The main principles and objectives of the LTE-SAE architecture include:
A common anchor point and gateway (GW) node for all access technologies
IP-based protocols on all interfaces
All IP network - Simplified (and much cheaper!) network architecture
All services are via Packet Switched domain
Support mobility between heterogeneous RATs, including legacy systems as GPRS,
but also non-3GPP systems (say WiMAX)

SAE - System Architecture Evolution
IASA - Inter-Access System Anchor

Duplexing Methods for Radio Links
Mobile Station
Base Station
Forward link
Reverse link

)FDDDivision Duplex (Frequency
Forward link frequency and reverse link frequency are different
In each link, signals are continuously transmitted in parallel
Mobile Station
Base Station
Forward link (F1)
Reverse link (F2)

Example of FDD systems
Transmitter
Receiver
BPF: Band Pass Filter
BPF
BPF
Transmitter
Receiver
BPF
BPF
F1
F2 F1
F2
Mobile Station Base Station

)TDDDivision Duplex (Time
Forward link frequency and reverse link frequency is the same
In each link, signals take turns using the channel
Mobile Station
Base Station
Forward link (F1)
Reverse link (F1)

Example of TDD Systems
Transmitter
Receiver
BPF: Band Pass Filter
BPF
Transmitter
Receiver
BPF
F1 F1
Mobile Station Base Station
Synchronous Switches

Downlink Scheme - OFDM
LTE uses OFDM for the
downlink – that is, from
the base station to the
terminal.
OFDM meets the LTE
requirement for
spectrum flexibility and
enables cost-efficient
solutions for very wide
carriers with high peak
rates.
OFDM uses a large
number of narrow sub-
carriers for multi-carrier
transmission.
FDM
OFDM
User 1User 1User 1User 1 User 2User 2User 2User 2
OFDMA
Single user on
every channel
Multiple users on
every channel

Uplink Scheme - SC-FDMA
The LTE uplink transmission scheme for FDD and TDD mode is based on SC-
FDMA (Single Carrier Frequency Division - Multiple Access).
This is to compensate for a drawback with normal OFDM, which has a very
high Peak to Average Power Ratio (PAPR). High PAPR requires expensive and
inefficient power amplifiers with high requirements on linearity, which
increases the cost of the terminal and also drains the battery faster.
SC-FDMA solves this problem by grouping together the resource blocks in
such a way that reduces the need for linearity, and so power consumption, in
the power amplifier. A low PAPR also improves coverage and the cell-edge
performance.
Still, SC-FDMA signal processing has some similarities with OFDM signal
processing, so parameterization of downlink and uplink can be harmonized.

Multiple Antenna Techniques
MIMO employs multiple transmit and receive antennas to substantially enhance the air
interface.
It uses space-time coding of the same data stream mapped onto multiple transmit
antennas, which is an improvement over traditional reception diversity schemes where
only a single transmit antenna is deployed to extend the coverage of the cell.
MIMO processing also exploits spatial multiplexing, allowing different data streams to be
transmitted simultaneously from the different transmit antennas, to increase the end-user
data rate and cell capacity.
In addition, when knowledge of the radio channel is available at the transmitter (e.g. via
feedback information from the receiver), MIMO can also implement beam-forming to further
increase available data rates and spectrum efficiency

SISO, MISO, SIMO, MIMO …
SISO - Single Input, Single Output
SIMO - Single Input, Multiple Output
MISO - Multiple Input, Single Output
MIMO - Multiple Input, Multiple Output
MIMO Example

Beamforming
Beamforming is a technique
whereby the receiver (typically at a
base-station) adjusts its
transmission or more typically
reception parameters, so as to
concentrate on particular parts of
the cell and not in others.
The purpose of beamforming is to
Maximize the receptivity from the
user and two,
Minimize receptivity from a noise
source. The diagram below shows
how this works

Paired frequency bands defined by 3GPP
for LTE

Unpaired frequency bands defined by 3GPP
for LTE

TD-LTE and FD-LTE (TD-CDMA and FD-CDMA)
The two modulation schemes available in LTE have a high degree of commonality.
The differences exist to accommodate the fact that TD-LTE uses the same pipe to transmit
and receive.
The discontinuous nature of uplink and downlink, however, means operators have the
flexibility to adapt the UL/DL traffic ratio.
This feature allows operators to support different traffic types and symmetry, a common
feature with rich content and video delivery.

SON – Self Organized Network
The term Self-Organizing Network (SON) is generally taken to mean a
cellular network in which the tasks of configuring, operating, and
optimizing are largely automated.
SON focuses mostly on the radio-access, which is the most
consuming resource in the cellular network
One objective of SON is to eliminate as much pre-planning of network
configuration as possible. SON does allow for pre-planned network
configurations, but strongly encourages as much of the network
configuration be automatically generated / discovered as possible

LTE MBMS (E-MBNS) Concept
Digital radio and video transmission per network:
For all users on the
network
For all users in a
geographic area
For a group of users
One way or two-way
user-controlled service
MBMS - Multimedia Broadcast Multicast Services

Femtocells and Picocells
CustomerOperatorSite rental
Locally DeterminedCentrally PlannedFrequency/Radio
parameters
CustomerOperatorTransmission to
Operator’s Network
CustomerOperatorInstallation
FemtocellPicocellAspect

LTE-Advanced
Heterogeneous networks with macro, picocells, relays,
femtocells
Multi carrier aggregation of 40 MHz to 100 MHz
User Deployed Femtocells and Repeaters
Operator Deployed Picocells and relays

LTE-Advanced
Increased data rates and lower latencies for all users in the cell
Data rates scale with bandwidth - Up to 1 Gbps peak data rate
Aggregating 40 MHz to 100 MHz channels provide peak data rates of
300 Mbps to 750 Mbps1(2x2 MIMO) and over 1 Gbps(4x4 MIMO)

LTE - Advanced
LTE Advanced introduces 8x8 DL MIMO, 4x4 UL MIMO and UL
Beamforming

The Future Connections

LTE Operating Bands (TS36.101 rel. 9)

The Future – SP Commitments

Standardization Process (SEP-2010)

Part 3Part 3 –– Competitive Technologies andCompetitive Technologies and
Advanced NetworksAdvanced Networks

Lesson Content
WiFi and 802.11n
WiMAX

What is Wireless LAN (WiFi)?
General:
A wireless LAN or WLAN is a wireless local area network
Based on the IEEE 802.11 standards
Performance
Typical range is on the order of 10’s of meters
10’s to 100’s of Mbps, depends on standard
Reasonable reliability, low cost devices
Free frequency band – no licenses required !!!

Wireless and Mobile Communications – WiFi
802.11 published in 1997. Works in
The 2.4GHz Band. BW – up to 2 Mbps
Uses DSSS/FHSS Modulation
802.11a Published in 1999. Works in
The 5MHz Band. BW – up to 54Mbps
Uses OFDM modulation
802.11b Published in 1999. Works in
the 2.4GHz Band. BW up to 11.0 Mbps
Uses DSSS modulation
802.11g Published in 2003. Works in
The 2.4GHz Band. BW up to 54Mbps
Uses OFDM modulation
802.11n Published in 2007 (Draft).
Works in The 2.4/5.0GHz Bands. BW up to
248Mbps. Uses OFDM and MIMO

f3f2f1
The 802.11 Architecture
Fixed Terminals
AP
APAP

Unlicensed Frequency Bands
Ultra-low frequency (ULF) -- 0-3 Hz
Extremely low frequency (ELF) -- 3 Hz - 3 kHz
Very low frequency (VLF) -- 3kHz - 30 kHz
Low frequency (LF) -- 30 kHz - 300 kHz
Medium frequency (MF) -- 300 kHz - 3 MHz
High frequency (HF) -- 3MHz - 30 MHz
Very high frequency (VHF) -- 30 MHz - 300 MHz
Ultra-high frequency (UHF)-- 300MHz - 3 GHz
Super high frequency (SHF) -- 3GHz - 30 GHz
Extremely high frequency (EHF) -- 30GHz - 300 GHz
Extremely
Low
Very
Low
Low Medium High
Very
High
Infrared
Visible
Light
Ultra-
violet
X Ray
Audio
AM Broadcast
Shortwave Radio FM Broadcast
Television Infrared Wireless LAN
Cellular (840 MHz)
NPCS (1.9 GHz)
Ultra
High
Super
High
Ultra
Low
5.15-5.25GHz
5.25-5.35GHz
5.725-5.825
2.4 – 2.483GHz

802.11b/g Channels
2.400GHz 2.441GHz 2.483GHz
111 6
2 7
3 8
4 9
5 10
1 2 3 4 5 6 7 8 9 10 11
5MHz
22MHz
11 Non-overlapping channels
22MHz channel bandwidth, 5MHz channel spacing

The ISM Frequency Bands
The ISM (Industrial, Scientific and Medical) frequency bands
(900 MHz & 2.4 GHz) are un-licensed in most of the world
The ISM rules varies depending on the country:
In the US, the FCC allocates both the 900 MHz and 2.4 GHz band
with 1W maximum power
In Europe, the ETSI allocates only the 2.4 GHz band with 100
mW maximum power

What is WiMAX
WiMAX - Worldwide Interoperability for Microwave Access
Fixed (and nomadic) access: 802.16-2004/802.16d (8/2004)
Mobile access: 802.16e (5/2005)
Typically 2-8 Km’s, Maximum cell size ~45 Km’s
Maximum speed 100 Mbps (64QAM/20MHz)

Wireless and Mobile Communications –
WiMAX
Mid-late 90’s
Early technologies – LMDS, MMDS
No standardization
2001-2003 Early standards,
802.16 - 10-66GHz LOS,
802.16a – 2-11GHz NLOS
2004 – 802.16-2004 (802.16d)
Revision and consolidation of all of
the above
2005 – 802.16e (802.16-2005)
OFDMA, Mobility, Improved security,
Improved MIMO, Competing 4.0G

WiMAX Topologies
Fixed P2P
Backhaul
(802.16-2004)
Fixed P2MP
Backhaul (LOS)
(802.16-2004)
802.16-2004
Fixed/Nomadic
Access Provider/Enterprise
Network (NLOS)
(802.16-2004/802.16d)
Nomadic Broadband
complementary to 3.0G-4.0G
(802.16e)

802.16d (802.16-2004)
IEEE standard for the fixed wireless broadband
802.16d supports both services:
Time division duplex (TDD)
Frequency division duplex (FDD)
Used for fixed access:
Outdoor – when the antenna is located outside the building
Indoor – when the antennas are located inside the building

802.16-2004 (previously 802.16d)
Wi-Fi
Directional antennas
When installed, it’s aligned with base station
It’s fixed – it never moves location
Always higher throughput than omni-directional antenna
Applications
Rural / Macro-cell deployments
Wi-Fi hot spot backhaul
High bandwidth residential connectivity
Challenging environments
Fixed WiMAX,
Outdoor
Subscriber Station

802.16-2004 (previously 802.16d)
Omni-directional antenna
Do not require alignment with base
station
Portable but fixed when in use
Lower throughput than directional
Applications
Consumer CaTV/DSL-like
broadband
Customer self installation
predecessor for portable/mobile
Fixed WiMAX,
Indoor
Subscriber Station

WiMAX Mobility - 802.16e
Omni-directional antenna
Not aligned with base station
Location can vary
Portable to support both fixed and mobile use
Can be moving while in use
Lower throughput than directional antenna
Lower throughput than Omni-directional (Indoor Fixed)
Applications
Competitor to the 4.0G cellular networks

Part 4Part 4 –– Advanced NetworksAdvanced Networks

Lesson Content
The "All-IP" core network structure
Mobile IP
SIP and IMS

AIPN – All IP Network – Network Architecture
Service Environment:
Servers and Services
IP Backbone:
MPLS, Ethernet.
Routing environment
Access Networks:
Cellular, WIFi,
Copper, Optical, …
LTE
Pre-LTE Land-Line
WiFi/WiMAX

The Problem with Mobility
Internet
Host B
Gateway A
171.68.0.0
Gateway C
140.31.0.0
Mobile Node
171.68.69.10
“Connect to
171.68.69.10”
Gateway A replies to Host B with an ICMP host
unreachable
The mobile node (laptop), can work on in two ways:
Fix IP, in which the new local network will not recognize him
Dynamic IP, in which it will take up to several minutes to the network to know him
(ideally)
Where is 171.68.69.10???
141.31.0.0/16

SIP and IMS
SIP – Session Initiation Protocol
Signaling protocol for IP-Based networks
Signaling for all application types – Voice, Video, gaming, Net-
Meeting, Social-Networks ….
IMS – IP Multimedia Subsystem
Signaling, media and billing protocols, for multimedia over cellular
networks

Summary
Thanks for your time
Yoram Orzach
NDI Communications
yoram@ndi.co.il

Introduction To Cellular Networks

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