IEEE 802.16 and Beyond - 國立臺灣大學b89100/WiMAX/20051015/...IEEE 802.16 and Beyond Wired to...

IEEE 802.16 and BeyondWired to the MAX

Sheraton Taipei Hotel 28-30 Sept. 2005

Ken StanwoodCEO, Cygnus Communications

Vice-chair of IEEE 802.161

About the Speaker

• Ken Stanwood– CEO of Cygnus Communications– Vice-chair of IEEE 802.16– Co-founder of WiMAX– Previous WiMAX board member– 9 BWA patents and 15 applications

Cygnus Communications“Connecting Your Universe”

2

Some Terminology

• AP – Access Point• BS – Base Station• BWA – Broadband Wireless

Access• DFS – Dynamic Frequency

Selection• FEC – Forward Error

Correction• LOS – Line of Sight• MIMO – Multiple Input Multiple

Output• NLOS – Non-Line of Sight

• OFDM – Orthogonal Frequency Division Multiplexing

• OFDMA – Orthogonal Frequency Division Multiple Access

• QAM – Quadrature Amplitude Modulation

• QoS – Quality of Service• SoC – System on a Chip• SS – Subscriber Station


3

Outline

• Introduction to 802.16• History and Purpose of WiMAX• 802.16 Applications• Technical Description• Relationship to Other Standards• Future


4

The Problem to Solve

• Last Mile Extension of Fiber and Cable– Users want access to networks– Network operators want access to customers– Backhoes do not follow Moore’s Law– Fast local connection to network

• Multimedia Distribution– Data– Data with QoS (Gaming, etc.)– Voice– Video distribution– Real-time videoconferencing


5

Challenges 802.16 Needed to Address

• Differentiated services– Data– Voice– Video distribution– Real-time

videoconferencing

• Tough RF environments– Mobility– NLOS– Walls– Fading


6

Why not Wi-Fi or Wireless DOCSIS?


7

• Wi-Fi– Designed as wireless

replacement for Ethernet– Less efficient use of

spectrum– Added priority, but not QoS– CSCA great for LAN, but

not multimedia– Security has been

improved– 802.11n adding bandwidth,

but not deterministic QoS– Significant packet

overhead

• DOCSIS– QoS very similar– Request/Grant scheme

less efficient in bandwidth and delay

– Significant packet overhead

– 802.16 basic security taken from DOCSIS

– 802.16 message extensibility taken from DOCSIS

– Doesn’t handle PHY changes

Properties of IEEE Standard 802.16

• Broad bandwidth– Up to 96 Mbps (>70 Mbps throughput) in 20 MHz channel (in

WirelessMANTM-OFDM air interface)• Supports multiple services simultaneously with full QoS

– Efficiently transport IPv4, IPv6, ATM, Ethernet, etc.• Bandwidth on demand (frame by frame)• MAC designed for efficient use of spectrum• Comprehensive, modern, and extensible security• Supports frequency allocations from <1 to 66 GHz

– ODFM and OFDMA for non-line-of-sight applications


8

Properties of IEEE Standard 802.16

• TDD and FDD• Link adaptation: Adaptive modulation and coding

– Subscriber by subscriber, burst by burst, uplink and downlink

• Point-to-multipoint topology, with mesh extensions• Centralized scheduling allows efficient use of available

bandwidth• Support for adaptive antennas and space-time coding

– Beamforming and MIMO

• Power control allows coverage from feet to miles• Extensions for mobility are coming next.


9

Battery Life

• Power Control• Subchannelization

– SS power amplifier– Saves cost too!

• Beamforming– Reduction in SS transmit power

• Sleep mode


10

Coexistence with 802.11

• Compatible frequency plan– Two 10 MHz (or one 20 MHz) wide channels

occupy the 20 MHz of spectrum used by an 802.11 channel

• DFS– Detect other users and select different

channel• Beamforming

– Minimize interference


11

Status of IEEE 802.16 Standards

• Semiconductor manufacturer’s view– Coming to closure – slowly– Mobility is bigger yet

• BS-BS interoperability and communication• MIBs, Network, and Element management• Billing, SLAs, and Authentication

– New features always on horizon• Repeaters/Mesh


12

IEEE 802.16 Project


13

802.16a(Jan 2003)

• Extension (amendment) for 2-11 GHz• Targeted for non line of sight, Point-to-

Multi-Point applications like “last mile”broadband access

802.16(Dec 2001)

• Original fixed wireless broadband air Interface for 10 – 66 GHz

• Line-of-sight only, Point-to-Multi-Point applications802.16c

(2002-2004)

802.16 AmendmentWiMAX System Profiles

10 - 66 GHz

• Formerly 802.16REVd (802.16d) • Consolidate 802.16, 802.16a & 802.16c

and add System Profiles & Errata for 2-11 GHz in support of 802.16e requirements

• Prep for Mobility

802.16-2004(Sept 2004)

IEEE 802.16 Project (cont’d)

• Standardized MIBs for Fixed BWA802.16 Corrigendum

Errata only


14

• Management Plane Procedures and Services for Fixed and Mobile BWA

802.16e(11/2005 exp.)

• Amendment for Mobile wireless broadband up to vehicular speeds in licensed bands <6 GHz

• Enables roaming for portable clients roaming for portable clients (laptops) within & between service areas(laptops) within & between service areas802.16 cor

(11/2005 exp.)

802.16g(1/2007 exp.)

802.16f(3/2006 exp.)

IEEE 802.16 Leadership

• Chair: Roger Marks• Vice Chair: Ken Stanwood• Secretary: Dean Chang

– Corrigendum Task Group Chair: Jon labs– TGe Mobility Chair: Brian Kiernan– TGf and TGg (MIBs and Management Plane)

Chair: Phil Barber


15

Getting Involved

• Participation is on an individual basis• Earn vote based on attendance

– Can earn vote based on contribution• Always looking for people to help

– Editors– Task group officers

• IEEE 802 Plenary meetings every March, July, and November

• 802.16 interim meetings every January, May, and September


16

Contributing


17

• Depends upon the status of a task group• Proposals for study groups and new task

groups• Contribution of initial material• Letter ballots

– Comments and comment resolution• Sponsor ballots

– Comments and comment resolution

Outline



18

WiMAX History


19

• First meeting April 2001 in Antibe, France• Founding companies:

– Ensemble– Nokia– Harris– CrossSpan

• Initially concentrated on 10-66 GHz• Huge expansion started in Jan 2003

– Intel PR engine

WiMAX Purpose

• To promote a common broadband wireless standard

• To develop reduced scope “profiles” to ease development

• To fill the gaps in the IEEE process relative to the ETSI process

• To create a broadband wireless access conformance and interoperability certification process

• To act as a certification body


20

Filling the Gaps - System Profiles

• Allow scope reduction while maintaining interoperability

• Targeted towards common market opportunities

• The most common system implementations


21

Filling the Gaps – Test Specifications

• “ETSI-style” ISO/IEC 9646 compliant test specifications– PICS proforma– Test Suite Structure and Test Purposes

(TSS&TP)– Radio Conformance Test (RCT)

Specification– Abstract Test Suite (ATS)


22

Conformance is not Interoperability

• Conformance – tested in independent test lab

• Interoperability – tested via PlugFests• Certification = Verified Conformance +

Interoperability


23

WiMAX Certification

• Certifies– Interoperability of equipment to other vendor’s BS/SS– Conformance to WiMAX defined PICS, TSS&TP

based on IEEE 802.16 and ETSI HiperMANstandards

IEEE802.16

Standard WiMAXTSS&TP

WiMAXPICSETSI

HiperMANStandard


24

Test Suites Structure& Test Purposes

Protocol ImplementationConformance Statement

Outline



25

Applications of IEEE 802.16• Fixed BWA

– 3G/4G Backhaul– Metro Ethernet– Wireless first-mile solutions

• Mobile BWA– Mobile handheld / handsets– Laptops/PDAs

• Government/Homeland Security– First responders network– Municipalities

• In-home Multimedia Distribution– N x HDTV, VoIP, data, gaming– Access points, cordless phones, adapters, appliance integration

(built-ins)


26

Market Segments for Wireless Access

PointPoint--toto--Multipoint Multipoint 1010--40GHz40GHz

Fiber

150 Mbps

50 Mbps

20 Mbps

10 Mbps

2 Mbps

500 kbps

56 kbps

1 GbpsFSO

PtP

xDSL, Cable

PmP<11 GHzD

ata

Rat

e

MobileBackhaul

ResidentialSOHO

SmallBusiness

MediumBusiness


27

Multi-Tenant

Residential

LargeBusiness

Addressable Markets

802.16 BWA in Metro Ethernet

OpticalMetro Ethernet

CE

CE

EthernetUNI

EthernetUNI

EVC 1

EVC 2

EVC 3 EthernetBackhaul

802.16Base

Station

802.16SS

802.16SS


28

Wireless Tower and Hot Spot Backhaul

• Highly Scalable• Highly reliable

– Copper T1’s are the biggest reliability issue in the network today

• Simple & quick Provisioning• Low cost nxT1 capability


29

PMP Range

PtP Range

TNCTNC

Selecting an IEEE 802.16 PHY

• WirelessMAN-SC– Targeting market above 11 GHz– LOS

• WirelessMAN-SCa– Targeting market below 11 GHz– Very little industry support– Mostly LOS

• WirelessMAN-OFDM– Targeting Market below 6 GHz– NLOS and Near LOS operation– Current choice for fixed systems

• WirelessMAN-OFDMA (scalable)– Targeting Market below 6 GHz– NLOS and Near LOS operation– Current choice for mobile systems


30

Outline



31

Reference Model


32


33

3rd Gen. Technology in 802.16

Adaptive TDDvariable asymmetry in a single

broadband channel best matchesbandwidth to demand

frequency

time Adaptive TDMATrue bandwidth on demand and

variable packet sizes providedifferentiated, bursty services

to multiple users

QPSK

Q16

distance

Adaptive Modulation & FECvariable modulation & coding maximizes

both air-link capacity and coverageQ64

Adaptive Burst Profiles

• Burst profile– Modulation and FEC

• Dynamically assigned according to link conditions– Burst by burst, per subscriber station– Trade-off capacity vs. robustness in real time

• Roughly doubled capacity for the same cell area• Burst profile for downlink broadcast channel is well-

known and robust– Other burst profiles can be configured “on the fly”– SS capabilities recognized at registration


34

QAM-64QAM-64

99.993%~ 4 hrs/yr

85% of Channel Capacity99.95%*

~ 364 days 19.5 hrs/yr

100% of Channel Capacity99.999%,

~ 20 min/yr

70% Channel CapacityQPSK QAM-16 QAM-64

2-3km*

QAM-16 QAM-64QPSK QAM-16 QAM-64

2-3km*

QAM-16 QAM-64

Coverage/Capacity Advantage of Adaptive PHY

Burst profile changes dynamically to match propagation path conditions


35

Dedicated, Fixed Symmetry with FDD


36

Spectral Efficiency with Adaptive TDD


37

802.16 Supports MIMO• MIMO uses multiple antenna and RF architectures. This can be

used to provide an increase in system gain or capacity or a combination of both

• System gain improvements (link budget gains) are seen when using Alamouti STC spatial diversity

• System capacity improvements are seen when using spatial multiplexing

• In 802.16 both are supported by the use of MIMO options.


38

802.16 Supports Beamforming (AAS)

• High system gain for maximum coverage and availability

• Use for extended range or increased capacity

• Penetrate walls• Null interferers• Reduction in overall levels of interference• SS can be omni-directional• Modified frame structure for network entry

in 802.16• Technology well suited to a macro cellular

propagation environment


39

The physical layer of 802.16 supports mechanisms for mesh realization using

MIMO and AAS

Coverage of Downtown L.A.

PtPPMP

>6km>10km

Sufficient range to cover entire downtown area


40

802.16 MAC: Highlights

• Point-to-Multipoint• Connection-oriented• Supports difficult user environments

– High bandwidth, hundreds of users per channel– Continuous and burst traffic– Very efficient use of spectrum

• Protocol-Independent core (ATM, IP, Ethernet, …)• Balances between stability of contentionless and

efficiency of contention-based operation• Flexible QoS offerings

– CBR, rt-VBR, extended rt-VBR, nrt-VBR, BE, with granularity within classes

• Supports multiple 802.16 PHYs


41

IEEE 802.16 MAC – Three Sublayers

• Service Specific Convergence Sublayer (CS)– Mapping upper-layer data into MAC SDUs– upper-layer data traffic classifications– Payload header suppression (PHS) -- Optional

• MAC Common Part Sublayer (MAC CPS)– System access control– MAC PDU encoding and decoding– Bandwidth management– QoS provision

• Privacy Sublayer– Secures over-the-air transmissions– Protects from theft of service


42

ATM Convergence Sublayer

• Full QoS support• Support for end-to-end signaling of

dynamically created connections – SVCs & soft PVCs

• Support for VP (Virtual Path) and VC (Virtual Channel) switched connections

• ATM header suppression


43

Packet Convergence Sublayer

• Support for Ethernet, VLAN, IPv4 and IPv6 based services

• Full QoS support• Payload header suppression


44

Some MAC Considerations

• Address the Wireless environment• Different transport protocols

– ATM, IP• Broadband services

– Very high bit rates, downlink and uplink– Different QoS requirements

• Likelihood of Terminal being shared– Combined with previous issue may heavily load Base Station

• Network Access• Security


45

802.16 QoS Building Blocks


46

• Four classes of service– Constant rate– Real-time variable rate– Non real-time variable rate– Best effort– Extended real-time variable rate (hybrid of constant rate and rt

variable rate)• QoS and Traffic Parameters

– Maximum bit rates– Guaranteed bit rates– Priority– Delay– Jitter

802.16 QoS Building Blocks

• Clock regeneration– Regeneration of multiple network clocks

• Centralized scheduling to maximize throughput

• Still subject to implementation quality– Fairness algorithms– Call admission control– Request/grant


47

Centralized Scheduling with Just a Touch of Chaos


48

• Self-correcting protocol– No acknowledgements

• Discrepancies– BS did not hear request– SS did not hear grant– Bandwidth stealing– Packing and fragmentation overhead– Insufficient bandwidth

• Tools– Incremental and Aggregate BW requests– Zero-length bandwidth requests

Centralized Scheduling with Just a Touch of Chaos

• Request by connection– Necessary for fairness/QoS calculations

• Grant by terminal– Efficiency– Flexibility

• Request/Grant Strategies– Unsolicited grants– Polling – unicast, multicast, broadcast– Piggybacking– Bandwidth stealing


49

MAC PDU Transmission


50

MAC Message SDU 1 SDU 2

Fragmentation Packing

MAC PDUs PDU 1 PDU 2 PDU 3 PDU 4 PDU 5

FEC 1 FEC 2 FEC 3

Concatenation

Burst P

Shortening

PreambleMAC PDUs FEC blockP

Multiple Access and Duplexing

• On DL, SS addressed in TDM stream• On UL, SS allotted a variable length TDMA slot

• Time-Division Duplex (TDD)– DL & UL time-share the same RF channel– Dynamic asymmetry– SS does not transmit/receive simultaneously (low cost)

• Frequency-Division Duplex (FDD)– Downlink & Uplink on separate RF channels– Static asymmetry– Half-duplex SSs supported

• SS does not transmit/receive simultaneously (low cost)


51

802.16e Frame-Based Transmission


52

• Frame duration is specified by frame duration code in DL-MAP, broadcast at beginning of every MAC frame

• Possible frame durations vary by PHY choice

• BS TDD turn-around time:–TTG: Transmit/receive Transition Gap–RTG: Receive/transmit Transition Gap–Specified in DCD message

• SS/MS TDD/H-FDD turn-around time:–SSTTG: SS TTG–SSRTG: SS RTG–Specified in SBC-xxx messages

Downlink Subframe


53

TDMA portion: transmits data to some half-duplex SSs (the ones scheduled to transmit earlier in the frame than they receive)Need preamble to re-sync (carrier phase)

Typical Uplink Subframe


54

Burst Structure

• Concatenation– Combining 2 or more MAC PDUs into one

PHY burst• Packing

– Combining 2 or more MAC SDUs (or fragments) into on MAC PDU

• Fragmentation• Payload header suppression (PHS)


55

Security and Encryption

• Provide extensible privacy, theft of service protection

• Authentication– Based on RSA public key and X.509 certificate– Authenticate terminals– Authenticate connection establishment

• Encryption– 56-bit DES CBC or 128 bit AES

• Protocol is modification of BPI+ (from DOCSIS)• 802.16e is extending to equivalent of 802.1x


56

Overview of 802.16 PHYsSC SCa OFDM OFDMA

Spectrum 10 – 66GHz below 11 GHz below 11 GHz below 11 GHz

Channel condition

LOS only LOS only Designed for NLOS

Designed for NLOS

Cell Raius 2 to 5 Km 5 to 12 Km 5 to 12 Km 5 to 12 Km

Channel Bandwidth

20, 25, & 28 MHz

1.25 to 20 MHZ (flexible)



Duplexing Mode

TDD/FDD TDD/FDD TDD/FDD TDD/FDD

Modulation Single carrier: QPSK, 16QAM, 64QAM

Single carrier: QPSK, 16QAM, 64QAM, 256QAM

OFDM (256 FFT): BPSK, QPSK, 16QAM, 64QAM

OFDM (128, 512, 1K, & 2k FFT): BPSK, QPSK, 16QAM, 64QAM

Raw Bit Rate 32 to 134.4 Mbps

1 to 75 Mbps 1 to 75 Mbps 1 to 75 Mbps


57

Physical Layer Tools

• Subscriber level adaptive physical layer• Subchannelization• OFDM/OFDMA for mobility• Beamforming• MIMO• Space-Time Coding (STC)• Dynamic Frequency Selection - DFS


58

802.16 SC PHY Specifics


59

802.16 SC PHY Specifics

• Modulation choices:– QPSK– 16QAM – 64QAM

• FEC– Reed Solomon– For robust communications the RS code is

concatenated with a BCC– Turbo Codes (TPC) are optional

• Frame length is either 0.5, 1 or 2 ms– As baud rate increases smaller frames are used


60

SC PHY: Baud Rates & Channel Size


61

• Flexible plan - equipment manufactures choose according to spectrum requirements– 10 to 32 MBaud

• Recommended baud rates in the standard are suitable for worldwideworldwide deployments– 28 MHz (22.4 MBaud)– 25 MHz (20 Mbaud)

• Frame length is tied to the baud rate

802.16 OFDM PHY Specifics


62

802.16 OFDM PHY Overview

• below GHz• 256-point FFT• 192 data carriers + 8 pilot carriers = 200 active

carriers• Concatenated coding for forward error correction

(FEC)• Optional Turbo Coding• BPSK, QPSK, 16-QAM, 64-QAM (optional) with

various coding rates• subchannelization optional


63

OFDM Symbol

Time Domain


64

Frequency Domain

IEEE 802.16 MAC – OFDM PHY TDD Frame Structure


65

DL Subframe

Frame n-1

pre.

Time

Adaptive

Frame n Frame n+1

UL subframe

FCH DLburst 1

DLburst n

ULMAP

Broadcast Conrol msgs

... UL burst 1 UL burst m

DLMAP

DCDopt.

UCDopt.

...DLburst 2

UL TDMADL TDM

pre. pre.

IEEE 802.16a MAC – OFDM PHY FDD Frame Structure


66

DL Subframe

Frame n-1

pre.

Time

BroadcastControl Msgs

Frame n Frame n+1

UL subframe

FCH DLburst 1

DLburst k...

DL TDMA

UL burst 1 UL burst m

DLburst 2

DLburst n

DLburst k+1 ...

DL TDM

...

UL TDMA

DLMAP

ULMAP

DCDopt.

UCDopt.

pre.pre.

UL MAP for nextMAC frame UL

burstspre. pre.

OFDM PHY: Raw Bit Rate (Mbps)

Modulation / Code Rate

QPSK 3/4 16 QAM 1/2 16 QAM 3/4 64 QAM 2/3 64 QAM 3/4

1.75MHz 2.18 2.91 4.36 5.94 6.55

3.5MHz 4.37 5.82 8.73 11.88 13.09

7.0 MHz 8.73 11.64 17.45 23.75 26.18

10.0MHz 12.47 16.63 24.94 33.25 37.40

20.0MHz 24.94 33.25 49.87 66.49 74.81


67

802.16 OFDMA PHY Specifics


68

802.16 OFDMA PHY Overview

• Below 6 GHz• 128, 512, 1024, or 2048-point FFT• Concatenated coding for forward error

correction Optional Turbo Coding• Scrambler is used to randomize the data• QPSK, 16-QAM, 64-QAM (optional) with

various coding rates• subchannelization mandatory


69

Some OFDMA Basic Terms• Subchannel

– A subset of active subcarriers• Permutation

– the way how subcarriers form subchannels, e.g., adjacent or distributed, ect.

• Permutation Zone– A number of contiguous OFDMA symbols, in the

UL or DL, that use the same permutation formula.• Segment

– A set of subchannels that are used for deploying a single instance of the MAC.


70

OFDMA Frame Structure

71

802.16e OFDMA Frame With Multiple Permutation Zones


72

OFDMA: Multiple Different Permutations• PUSC

– Partial Usage of SubChannels: not all the subchannels are allocated to the transmitter;– Divide the subcarriers into clusters with zero carriers allocated, and then allocate pilots and data

carriers in each cluster.• Optional PUSC

– Additional optional symbol structure for PUSC– UL only

• FUSC– Full Usage of SubChannels: all subchannels are allocated to the transmitter;– Allocate pilots with zero subcarriers, then allocate data subcarriers.– DL only

• Optional FUSC– Additional optional symbol structure for FUSU– DL only.

• AMC– Advanced Modulation/Coding (bad name!)– Adjacent subcarrier permutation

• TUSC1– Tile Usage of SubChannels –1– DL only– AAS zone only

• TUSC2– Tile Usage of SubChannels – 2– DL only– AAS Zone only


73

OFDMA Allocation Terms

• slot– Minimum allocation unit;– The definition of a slot varies with:

• UL / DL• Permutations

• Data Region– A two-dimensional allocation of a group of contiguous

subchannels, in a group of contiguous OFDMA symbols.


74

OFDMA Allocation Unit --- Slot Definitions

Permutations DL Slot definition UL Slot definition

PUSC One subchannel by Two OFDMA symbols

One subchannel by Three OFDMA symbols

One subchannel by Three OFDMA symbols

n/a

n/a

One subchannel by One OFDMA symbols

n/a

n/a

Optional UL PUSC

n/a

FUSC One subchannel by One OFDMA symbols

Optional DL FUSC

One subchannel by One OFDMA symbols

AMC One subchannel by One OFDMA symbols

DL TUSC1 One subchannel by Three OFDMA symbols

DL TUSC2 One subchannel by Three OFDMA symbols


75


76

OFDMA DL Allocation and Data Mapping

Subc

hann

el In

dex

0 1 2 ……

……

……

……

……

……

……

……

……

……

……

……

……

….. L -1

prea

mbl

e

Prea

mbl

e

PU

SC

(DL_

Perm

Base

0,

cont

aini

ng F

CH

and

D

L-M

AP)

PU

SC

(D

L_Pe

rmBa

se Y

)

FUS

C(D

L_Pe

rmBa

se Z

)

Opt

iona

l FU

SC

FUS

C(D

L_Pe

rmBa

se 0

)

OFDMA UL Burst Allocation and Data Mapping• Two types of UL allocation:

– Block allocation (two dimensional: subchannel by symbol)

• UIUC=0, 12, 0r 13• Specified by

– Symbol offset– Subchannel offset– Number of symbols– Number of subchannels

– Slot allocation (linear: duration in slots)• UIUC = 1 to 10• Specified by number of slots• Allocated in time-domain first manner, i.e.,

symbol-first, then subchannels• Not more than one UL-MAP IE with UICU=1 to 10

for a SS• Data mapping in an UL allocation

– frequency-domain first, then time-domain, i.e., subchannel-first, then symbols.

– Skip the allocations made by IEs with block allocations.

• Not more than one UL burst with burst profile UIUC= 1 to 10 for each SS in an UL subframe; (this does not apply to HARQ regions).

text

OFDMA data Symbol index

UL burst allocation, time-domain first, then freqeuncy-domain

-- UL data mapping in an UL burst, frequency-domain first, then time-domain-- skip the blocks allocated by the block allocaitns

UL Subframe

Optional PUSC zonePUSC Zone AMC zone

Slot 0

Slot 1

Slot 2

Slot 3

Slot 4

UL Burst #1

UL Burst #2

UL Burst #3

UL Burst #4

UL Burst #5

0 1 2 3 4 5 6 7 ………………………………………………………………………………….. m

PUSC UL slot = 1 subchannel * 3 symbols

Burst allocated by UIUC=12

Slot k

Slot k+1

Slot k+2

Slot k+3

Slot k+4


77

Outline



78

Creating a Standard

• Different strategies– Try to get an existing, proprietary system

standardized (IS-94, 802.20)– Come with proposal to new working group for

future system (802.16)• Different standards body procedures

– IEEE 802– ETSI– CEA


79

802.16 and ETSI

• Over 50 liaison letters between 802.16 and ETSI (European Telecom Standards Institute)

• ETSI HIPERMAN– Below 11 GHz– Healthy cooperation– Harmonized with WirelessMANTM-OFDM


80

802.16 and ITU

• ITU-T January 2004:– 802.16 approved as draft recommendation for

wireless extension of cable operator footprint.– Included in-home

• ITU-R November 2004:– Liaison statement– Return statement from 802.16– Working towards ITU BWA recommendation


81

802.16 and WiBro

• Numerous liaison letters between 802.16 and WiBro– WiBro very similar to subset of 802.16e– Healthy cooperation with WirelessMAN-SCa– On-going harmonization


82

IEEE 802.20, 21, and 22


83

• 802.20– Billed as broadband mobility– Off to a very slow start– Recent events my revitalize, but could lead to a 1 company

solution• 802.21

– Media independent handoff between the different 802 standards – 802.3, 802.15, 802.11, 802.16, etc.

• 802.22– Use unused but licensed TV spectrum– 6 MHz channels– Some interest in using 802.16– Wireless microphones are incumbent but 95% illegally used

Outline



84

Extending 802.16 Applicability

85

Basic Premise

• It is desirable for the home or office to operate wirelessly

• The home and office require a multitude of media to coexist simultaneously without interfering with each other

• Certain applications cannot tolerate a degradation in service

• Compatibility between indoor and outdoor applications is desirable


86

What Does This Mean to the Home?

• Proper BWA requires a solution for high QoS multimedia in a low resource situation with a tough RF environment

• The home requires a solution for high QoS multimedia in a low resource situation with a tough RF environment

• 802.16 is designed to solve both problems


87

Vision - Wireless Multimedia Distribution in the home


88

802.16

CordlessPhone

PocketPC

Guaranteed and Best Effort Access

CBR TDM Voice

Best Effort Access

Real-Time Video

2xHDTVBroadband Service

802.16

Gaming

Real-Time Video2xHDTV

Tablet PCwith

Camera

802.16

802.16/11802.16/11

WiMAX802.16/11

AP

Set TopBox

Real

-Tim

e Vi

deo

2xHD

TV

HDTV

Gua

rant

eed

Dat

a Ac

cess

802.16802.16

802.16, Cable, DSL, IP

Extending the “Triple-Play”

• The “Quadruple-Play” – 4 classes of service– Voice– Video– Best Effort data– Data with guaranteed QoS

• Priority is NOT QoS• Extra bandwidth is NOT QoS


89

Always Best Connected

• Laptop or other device with both 802.11 and 802.16 capability

• 802.16e mobile data/voice device– Transition outdoors-indoors– Cordless phone is mobile phone


90

Complementary Capabilities

• IEEE 802.16/WiMAX– Distribution– Strict QoS– Mobility

• IEEE 802.11/Wi-Fi– Data LAN– Extensive Availability

• IEEE 802.15.x– Cable Elimination– Low Power– Numerous Application

Specific Variants


91

Hierarchical SystemsBACKHAUL


92

INTERNETBACKBONE

Non Line of SightPoint to Multi-point

INDOORCPE

MMDS Band

802.11 802.11 & &

802.16802.16

Point to Point

Always best connected


93

802.16 Base Station

Tuner

Cygnus 802.16 BS

SDR

Cordless Phone or

Mobile Handset

Cygnus 802.16 SS

ASIC

Cordless Phone or

Mobile Handset

Game console

Cygnus 802.16 SS

ASIC

Cygnus 802.16 SS

ASIC

Nomadic

Notebook PC

Cygnus 802.16 SS

ASIC

Notebook PC

VOIP

10/100 BaseTLAN Ports

Voice Ports

Network Processor

802.11a,g AP

Cygnus802.16e AP

ASIC

Tuner

Cygnus802.16e SS

ASIC

Memory

Connection Management in the Home

• Supporting true QoS• End-to-end or local? The dynamics of self-

organization• Service Level Agreement (SLA) vs. free or bundled• Call admission control (CAC), Congestion Avoidance,

reaction to changing RF and interference environment – Dynamic Service Allocation (DSA)

• Classification• Roaming• Theft of service• Digital Rights Management (DRM)


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Can 802.16 Meet the Price Point?


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• SS ASICs will follow 802.11 price curve• AP/BS ASICs are coming

– Needed for price point– Asymmetric protocol – a SS is not an AP

• Request/grant• Subchannelization• Beamforming

– Needed for size– Needed for heat dissipation

What Does This Mean to BWA?

• A true BS SoC allows traditional BWA to be driven down to <$100 per channel

• Decreased power and heat – pico base stations powered over their Ethernet backhauls

• Advanced techniques such as beamforming open the door for self install – reduced OpEx


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Mesh

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Why Mesh?

• Communication within a local community– How often is this true?

• Capacity increase– Obvious if local community– Difficult to achieve otherwise

• Alternative path– Modeled after the core network

• Cost effective range extension– Reduce base station nodes while user community sparse

• Is the mesh a mesh or a tree? How rich is the mesh?– Increased riches provides resiliency, but presents a more

complex planning and management task.


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Advantages of Mesh• Adds capacity under the right circumstances• Supports scalability, reduces infrastructure costs• Increases range and steers around LOS blockages• Resilience to unit failure with the provision of backup

paths• As the network grows and becomes more dense then

average power reduces and probability of coverage increases

• Potential for very high spectral efficiencies –dependent on antenna technology used


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Challenges for Mesh• Delays incurred with multiple hops and processing

delay – preservation of QoS• Cost of network elements – in the limit requirements

for a combined BS/CPE solution• Incremental cost of planning and management• Increased cost associated with support for routing

functionality and possible propriety signaling.• Possible frame structure dependencies for

interference avoidance in license-exempt spectrum –coordinated avoidance

• Capacity constraints at branch/mesh extremities & necessity for high capacity at mesh ingress points

• Possible requirements for timing synchronization


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Mesh Realization• Broadly speaking there are two realizations for mesh: logical and

physical - driven by the antenna technology employed and requisite support of network management

• Logical mesh– Use broad beam or omni-directional antennas to form logical links to

neighboring devices– Links are therefore logical in the respect that the hardware configuration is

unaltered for different links– Link information is maintained by network management entities

• Physical mesh– Use substantially directional antennas to create physical links– Links are therefore a physical realization as the hardware configuration

changes to form links to neighboring devices – Steers beams either electrically or mechanically

• Both realizations have their own benefits and challenges


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Logical Mesh–Lower C/I and

spectral efficiency–High reuse factor – Intra network

interference –needs protocol support

–Significant impact of external interference on large parts of the network

–Supporting a rich mesh can be difficult with few frequencies due to high reuse factor requirements

Adding a new node adds intra mesh interference

Interference impact on reuse


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Physical Mesh–Significantly

improved C/I–Low frequency

reuse–High spectral

efficiency–Complications for

network entry–More expensive

antenna systems–Complex

environment sensing with mechanical antennas

Interference impact on reuse – reduced due to a

smaller arc of impact

Adding a new node adds intra mesh interference

Mesh ArchitecturesBoth logical and physical meshes share categories of repeaters

that can be implemented

• RF repeaters: RF repeaters simply receive on one frequency and transmit on another, given sufficient spatial isolation the same frequency could be used

• PHY and MAC repeaters: PHY repeaters and MAC repeaters do increasingly more processing of the signal before forwarding it.They have the advantage of being able to be more intelligent about re-amplification of signals, but at the cost of delay and complexity. In the limit, a MAC level repeater becomes simply another BS or Ethernet bridge

• Network level repeaters: Use routing functionality to direct IP datagrams through the multi-hop system


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Mesh in 802.16 Currently in the StandardThe mesh mode in 802.16-2004 is a logical mesh. It supports interference

mitigation with MAC message support for scheduling . This mesh is self organizing mesh which consumes bandwidth and compromises QoS. This is built on top of standard PMP

– Uses the OFDM PHY– Designed primarily for cost-effective build out and range extension whilst

the user community sparse.– Not designed for local community communication

• All data goes back through an ingress/egress point– Not designed for capacity increase– Can provide alternative, backup paths– Assumes omni-directional antennas– Developed by Nokia in support of their RoofTop product line

DM (Directed Mesh) is a physical mesh and is supported in SC PHY (10-66GHz) only. It is based on a configuration of PMP mode. Used with directional antennas

– Developed by Radiant Networks to support their MESHWORKS™ products


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Both mesh implementations are currently unsupported in the standard

PHY Support for Mesh in 802.16


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802.16 provides:• AAS (Advanced Antenna System) supporting

beamforming• MIMO (Multiple Input Multiple Output) supporting:

– Spatial diversity schemes (Space Time Coding)– Spatial Multiplexing– Combination of the two techniques

• Exploitation of diversity and advanced antenna techniques for user installability and system gainenhancements

• Together with interference management in license exempt bands all require careful consideration for WiMAX mesh

Mesh in 802.16 for Future Development


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New Group meeting for the first time at 802.16 interim in May 2005 ‘Mobile Multi-hop Mesh Networking’. The group’s scope includes– Compatibility with PMP: 802.16-2004 and 802.16e– Efficient mesh/relay to MS (Mobile Station)– OFDM/OFDMA PHY support– Tentative schedule sees Study Group formed in

Sept. 2005 and Task Group initiated in May 2006

Mesh is currently a topic generating significant interest and contribution into the standard

Downlink Relay Uplink

Mesh System Concept


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>26GHz Backhaul

INTERNETBACKBONE

Non Line of SightPoint to Multi-point

2.5GHz bandPoint to Point/Multi-point

802.11 802.11 & &

802.16802.16802.16802.16

802.16802.16

A Mesh Example


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BS

SS

No coverageBS

SS

SS

SS

BS

SS

Mesh coverage

BS

SS

Mesh SS

SSBS

• Two BS required with mesh SS• Three BS required for full coverage

SS SS

Predictions

• WirelessMANTM-OFDMA (802.16e) will be the winner– Fixed systems will benefit from increased volumes– Fixed systems need the option to be fixed/mobile hybrids

• WiBro and near-WiBro will be the profiles of choice– TTA in Korea is settling on 802.16e options subset that satisfy

needs for mobile and fixed– Don’t fragment the market– Need channel width and duplexing flexibility for other countries

• The really big market is not BWA, but in-home multimedia distribution– In-home multimedia distribution– Mobile applications– Government/Homeland defense applications– Fixed BWA

• Mesh attributes will play an important role in successful systems


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Thank YouAny questions?

[email protected]

Address:2075 Las Palmas Drive

Carlsbad, CA 92009

www.cygnuscom.com


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IEEE 802.16 and Beyond - 國立臺灣大學b89100/WiMAX/20051015/...IEEE 802.16 and Beyond Wired to...

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Transcript of IEEE 802.16 and Beyond - 國立臺灣大學b89100/WiMAX/20051015/...IEEE 802.16 and Beyond Wired to...