WiMAX is a wireless technology that can provide broadband internet access over long distances. It uses multiplexing techniques like OFDM and OFDMA to allow efficient use of spectrum. The document discusses WiMAX network architecture including components like the base station, CPE/MS, and ASN-GW. It also covers topics like QoS classes, modulation schemes, antennas, and applications of WiMAX such as providing VoIP services.

1. WI-MAX
GROUP MEMBERS
SHAHEER SHAHBAZ HYDER
AIBAD AHMED
ALI HABIB
USAMA AHFAZ

2. CONTENTS
 INTRODUCTION
 WIMAX ARCHITECTURE
 QOS CLASSES
 MULTIPLEXING TECHNIQUES
 MODULATION SCHEMES
 WIMAX RADIOS
 APPLICATIONS

3. INTRODUCTION
BACKGROUND
 PROJECT DEVELOPMENT ON WIMAX WAS
START IN 1998.
WHY WIMAX?????
 Wi-Fi signals can not cover more than a
hundred meters.
 Both LOS and NLOS support.
 Higher data rate than former technologies.
 Fewer base stations.

4. CONT….
 WIMAX refers to interoperable implementations
of the IEEE 802.16 family of wireless-networks
standards ratified by the WiMAX Forum.
 There were some earlier version of Wimax that
were used for testing purposes:
802.16a ,802.16b ,802.16c .
 The current versions are 802.16d(FIXED) and
802.16e(MOBILE).

5. CURRENT DEPLOYMENT IN
PAKISTAN:
 Pakistan is the first country with world’s largest nationwide
installed WiMAX network
 Providers: Wi-Tribe, Wateen (3.5GHz), Mobilink Infinity,
Qubee.
 WiMAX could potentially be deployed in a variety of spectrum
bands: 2.3GHz, 2.5GHz, 3.5GHz, and 5.8GHz
 Operates in both licensed and un-licensed bands

6. WIMAX NETWORK
CHARACTERISTICS
 There are two scenarios for a wireless deployment: point-
to-point and point-to multipoint.
Point to Point (P2P):
 Point to point is used where there are two
points of interest: one sender and one
receiver.
 As the architecture calls for a highly focused
beam between two points range and
throughput of point-to point
radios will be higher than that of
point-to-multipoint products.

7. CONT...
Point-to-Multipoint (PMP):
 One base station can serve hundreds of dissimilar
subscribers in terms of bandwidth and services offered.

8. LINE OF SIGHT (LOS) OR NON-
LINE OF SIGHT (NLOS):
 WiMAX functions best in line of sight situations. Buildings
between the base station and the subscriber diminish the
range and throughput, but in an urban environment, the
signal will still be strong enough to deliver adequate service.

9.  WiMAX ability to deliver services non-line-of-
sight, the WiMAX service provider can reach
many customers in high-rise office buildings to
achieve a low cost per subscriber because so
many subscribers can be reached from one base
station.

10. WIMAX ARCHITECTURE END-
TO-END REFERENCE MODEL
NSP
NAP
R1 R3
MSS
R2
ASN CSN
ASP Netw ork OR
Internet
R4
Another ASN

11. DECOMPOSED ASN INTO BS AND ASN
GW ENTITIES

12. CPE OR MS
 CPE and MS are end-user products which
integrates with user devices
 Like laptops, mobile phones. it also includes USB
modem, PCMCIA cards
 Can be fixed or mobile

13. BASE STATION
 It provides connectivity to
the consumer equipments
 Base station consist of
wireless electronic tower
 Coverage area theoretically
up to 50km but practically 10 km
 Additional functions are: handoff triggering, QoS policy
enforcement, DHCP etc
 BS can be point-to point or point-to-multipoint
 BS are LOS as well as NLOS

14. ENTITIES OF THE WIMAX
NETWORK
 ASN: Access Serving Network
 Logical representation of the functions of a NAP, e.g.
 802.16 interface network entry and handover
 Radio Resource Management & Admission ctrl.
 L2 Session/mobility management
 QoS and Policy Enforcement
 Foreign Agent (FA)
 Forwarding to selected CSN

15. ASN-GW
 Access service network-Gate Way acts as a layer 2
traffic aggregation points within an ASN.
 management, network optimization, and forwarding
of all subscriber traffic, routing to the selected CSN ,
AAA client functionality.

16. CSN
 Connectivity service network provides:
 AAA servers that support authentication for
the devices
 Operations tools
 IP & traffic management
 QoS & Policy
 Pre paid billing
 Billing control
 support for roaming between
different NSPs

17. CONT....

18. AUTHENTICATION,
AUTHORIZATION AND
ACCOUNTING
 AAA refers to Authentication, Authorization and
Accounting.
 The AAA server provides the following services to
WiMAX:
 Authentication Services
 These include MS, user, or combined MS and user
authentication.
 Authorization Services
 These include the delivery of information to configure the
session for access, mobility, QoS and other applications.
 Accounting Services
 These include the delivery of information for the purpose of
billing (both prepaid and post paid billing) and information
that can be used to audit session activity by both the home
NSP and visited NSP.

19. INTERNETWORKING WITH 3GPP
Scope:
WiMAX-3GPP Interworking
refers to the integration of a
WiMAX Access Network to an
existing 3GPP core network.
3GPP
Card
WiMAX
Card
UE
Loosely-Coupled
Internetworking
3GPP Access
Network
RNC
GCSN
SGSN
3GPP Core
Network
WAG
PDG
Billing Server
Home AAA
Internet
Home Agent
WiMAX Network
Service Provider
Local AAA
WiMAX Base Stations
WiMAX ASN

20. WIMAX REFERENCE POINTS

22. QOS CLASSES
 Five QOS services are supported in WIMAX:
 UGS (Unsolicited Grant Service)
 RT-VR (Real-Time -Variable Rate Service)
 NRT-VR (Non-Real Time -Variable Rate service)
 BE (Best Efforts)
 ERT-VR (Extended Real-Time Variable Rate)

23. UNSOLICITED GRANT SERVICE
(UGS)
 support real-time data streams consisting of
fixed-size data packets issued at periodic
intervals
 Such as T1/E1 and Voice over IP without silence
suppression
VoIP

24. REAL-TIME POLLING SERVICE
(RTPS)
 support real-time data streams consisting of
variable-sized data packets that are issued at
periodic intervals
 Such as moving pictures experts group (MPEG)
video.

25. NON-REAL-TIME POLLING SERVICE
(NRTPS)
 support delay-tolerant data streams consisting of
variable-sized data packets for which a minimum
data rate is required
 such as FTP

26. BEST EFFORT (BE)
 support data streams for which no minimum
service level is required and therefore may be
handled on a space-available basis.

27. EXTENDED REAL-TIME
VARIABLE RATE (ERT-VR)
SERVICE
 support real-time applications with variable
data-rates, which require guaranteed data and
delay, for example VoIP with silence suppression.

28. MULTIPLEXING TECHNIQUES
OFDM
 OFDM divides the bandwidth into multiple
frequency sub-carriers.
 In OFDM sub-carriers are orthogonal to each
other.
 OFDM also uses multiple sub-carriers but the
sub-carriers are closely spaced to each other
without causing interference, removing guard
bands between adjacent sub-carriers.
 For fixed devices
 Orthogonal sub carriers produce no signal
power in adjacent sub carriers

30. BASEBAND OFDM SYSTEM

31. CONT....
 As a reminder, IFFT (Inverse Fast Fourier
Transform) is used in a WiMAX transmitter to
create an OFDM waveform from modulated data
streams, while FFT (Fast Fourier Transform) is
used in a WiMAX receiver to demodulate the
data streams.

32. WHY IS OFDM SO POPULAR FOR
NEW BROADBAND SYSTEMS?
 Most broadband systems are subject to multipath transmission
 Conventional solution to multipath is an equalizer in the receiver
 With OFDM there is a simple way of dealing with multipath
relatively simple DSP algorithms.
 It uses cyclic prefix to avoid residual ISI
 If multipath delay is less than the cyclic prefix
-no intersymbol or intercarrier interference
-amplitude may increase or decrease

33. OFDMA:
 OFDMA employs multiple closely spaced sub-carriers,
which are divided into groups of sub-carriers.
 For mobile services
 Point-to-point systems are OFDM, and do not support
OFDMA. Point-to-multipoint fixed and mobile systems use
OFDMA.

34. CONT....
 (OFDMA) is a multi-user version of the popular
(OFDM) digital modulation scheme
 Assigns different subset of sub-carriers to
individual user
 Bandwidth options 1.25, 5, 10, or 20 MHz
 Entire bandwidth divided into 128, 512, 1024 or2048 sub
carriers

35. SOFDMA:
 SOFDMA is used for mobile Wi-Max mode.
 It adjusts the size of FFT while fixing the sub-
carrier frequency
 Smaller FFT size is given to lower bandwidth
channels, while larger FFT size to wider
channels
 Capacity of each individual sub-channel remain
constant
 By making the sub-carrier frequency spacing
constant, SOFDMA reduces system complexity of
smaller channels and improves performance of
wider channels.

36. CONT....

37. SUB-CHANNELIZATION
 Defines sub-channels that can be allocated to
subscriber stations (SSs)
 Depends on :
 Channel Conditions
 Data requirement
 Base Station (BS) can allocate :
 more transmit power to user devices (SSs) with lower
SNR like for indoor SSs.
 less power to user devices with higher SNR.
 Subchannelization in the uplink can save a user
device transmit power because it can concentrate
power only on certain sub-channel allocated to it.

38. Picture. Uplink Subchannelization in WiMAX
In OFDM, only one SS transmits in one time slot.
In OFDMA, several SS's can transmit at the same time slot over several sub-
channels.

39. MODULATION SCHEMES
 In Wimax the modulation schemes used are:
 Qpsk (Quadrature Phase Shift Keying)
 QAM-16, 64, & 256
 QPSK uses four points on the constellation
diagram
 In QPSK the phase is changed in 4 ways for
sending data bits.
 QPSK can encode two bits per symbol.

40. CONT....

41.  QAM is a technique in which the amplitude and
phase varies simultaneously for sending higher
data rate
 QAM is a combination of ASK and PSK.
 In QAM-16, 4 bits are send on each single change
with the phase change of 22.5 degree
 In QAM-64, 6 bits are send on each single change
with the phase change of about 5.5 degree
 Same as for QAM-256 , 8 bits are send.

42.  Constellation diagram for QAM-16 and QAM-64

44. WI-MAX RADIOS
 A radio contains both a transmitter (sends) and a receiver
(receives).
 WiMAX antennas, just like the antennas for car
radio, cell phone, FM radio, or TV, are designed
to optimize performance for a given application.

45. OMNI DIRECTIONAL ANTENNAS
 Omni directional antennas are used for point-to-multipoint
configurations.
 Omni directional antenna broadcasts 360 degree from the base
station.
 Omni directional antennas are good for situations where there
are a lot of subscribers located very close to the base station.

46. SECTOR ANTENNAS
 A sector antenna, by focusing the beam in a more focused area,
offers greater range and throughput with less energy.
 Many operators will use sector antennas to cover a 360-degree
service area rather than use an omni-directional antenna due to
the superior performance of sector antennas over an omni-
directional antenna.

47. PANEL ANTENNAS
 Panel antennas are most often used for point-to-point
applications
 Panel antennas are usually a flat panel of about one foot
square.

48. APPLICATIONS

49. WIMAX VOIP
 Voice over Internet Protocol (VoIP) offers a wider range of
voice services at reduced cost to subscribers and service
providers alike.
 The diagram below illustrates a typical solution where a
WiMAX service provider can obtain wholesale VoIP services
(no need for the WiMAX service provider to install and operate
a VoIP soft switch) at about $5/number/month and resell to
enterprise customers at $50.