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IEEE 802.16 MAC and PHY Specifications

for Broadband WMAN

國立中興大學資工系 曾學文

Tel : (04)22840497 ext. 908 E-mail: hstseng@nchu.edu.tw

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Part Source : Roger B. Marks, National Institute of Standards and

Technology Boulder, Colorado, USA Chair, IEEE 802.16 Working Group

http://WirelessMAN.org

http://www.intel.com/idf

Resources

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Broadband Access to Buildings

• Wireless Metro Ethernet – 802.11 Wireless Ethernet

• First/Last mile access – Fast local connection to network

» 30%-40% Radio/TV pervasion » 5% internet access

– Target Applications (similar as DSL and CableModem) » Data » Voice / Audio » Video distribution » Real-time videoconferencing

• High-capacity cable/fiber to every user is expensive

– Network operators demand it – Business and residential customers demand it

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Comparisons of Wireless Standards

Source: International Telecommunications Union and WiMAX Forum

802.20

Fixed (Stationary)

Pedestrian (Nomadic)

Mobile (Vehicular)

2G/2.5G Cellular

0.1 1.0 10 100

Peak Data Rate per User (Mbits/second)

Mob

ility

Commercial Proposed

79 x 1 MHz Bluetooth > 100 UWB

<= 20 802.16 5 HSDPA

1.25

1xEV-DO, 1xEVDV, 802.20

1.25 2G/2.5G

Bandwidth (MHz)

Bandwidth Assumptions

WWAN (IMT-2000)

cdma2000® 1xEV-DO, cdma2000® 1xEV-DV

3.1

WCDMA HSDPA

802.15.1 (Bluetooth)

802.11 (WLAN)

802.16e

802.16a (WiMAX)

802.15.3a (UWB)

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Current Status

Source: Intel, the WiMAX Forum

• More Than 350 Operator Trials and Deployments in 65+ countries!

• List of operators – http://en.wikipedia.org/wiki/List_of_Deployed_WiMAX_networks

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4G (beyond 3G) / IMT Advanced

• 4G, a term used to describe the next complete evolution in wireless communications,

– is being developed to accommodate the quality of service (QoS) and rate requirements set by forthcoming applications for "anytime-anywhere".

• The 4G working group has defined the following as objectives of the 4G wireless communication standard:

– A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions

– Smooth handoff across heterogeneous networks – Seamless connectivity and global roaming across multiple

networks – High quality of service for next generation multimedia support

(real time audio, high speed data, HDTV video content, mobile TV, etc)

– An all IP, packet switched network.

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Wireless Broadband Evolution to 4G

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Standard Family Radio Tech Downlink (Mbps)

Uplink (Mbps) Notes

WiBro WiBro OFDMA 50 50 Mobile range (900 m)

802.16e WiMAX MIMO-SOFDMA 70 70 Quoted speeds only achievable at very short ranges, more practically 10 Mbit/s at 10 km.

HIPERMAN HIPERMAN OFDM 56.9 56.9

Flash-OFDM Flash-OFDM Flash-OFDM 5.3 10.6 15.9

1.8 3.6 5.4

Mobile range 18miles (30km) extended range 34 miles (55km); mobility up to 200mph (350km/h)

iBurst iBurst 802.20 HC-SDMA/TDD/MIMO 64 64 3–12 km

UMTS W-CDMA

HSDPA+HSUPA UMTS/3GSM CDMA/FDD

0.384 14.4

0.384 5.76

HSDPA widely deployed. Typical downlink rates today 1–2 Mbit/s, ~200 kbit/s uplink; HSPA+ downlink up to

Pre-4G

Source: Wikipedia

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HSPA (High speed packet access)

• HSPA+ boosts peak data rates to 42 Mbps on the downlink and 22 Mbps on the uplink

– Use MIMO and higher order modulation • HSDPA (D = downlink)

– 14.4 Mbps in downlink – 174 commercial networks in 76 countries – Can be achieved by software upgrade of

existing 3G networks • HSUPA (U = uplink)

– 5.76 Mbps in uplink

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LTE (Long term evolution) • Third Generation Partnership Project (3GPP)

Release 8 Standards in progress (expected 2009) – a project within the 3GPP to improve the UMTS

mobile phone standard

• Air interface is a completely new systems – based on OFDMA in the downlink and Single-

carrier-FDMA (SC-FDMA has low PAPR) in the uplink that efficiently supports multi-antenna techologies (MIMO).

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Wireless Metropolitan Area Network

Relay

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Application

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Fixed WMAN + Mobile WMAN

Source : WiMAX Forum

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WiMAX + Wi-Fi for Mobile Internet

• Wi-Fi -> best solution for local area connectivity – With up to 450 Mbps throughput, MIMO-enabled 802.11n enables new local

area applications – Wi-Fi hotspots easy to find in most places

• Mobile WiMAX -> metropolitan-wide broadband coverage – Offers service providers 3x the latest HSPA (3G) capacity today – Potential to scale to over 20x the capacity of today’s HSPA via more

antennas over time

Home

Work

Travel

Hot Spot

WiMAX Tower

Auto

Rural Outdoors WiMAX Tower

WiMAX WiFi

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Network Usage Model

Source : WiMAX Forum

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Features (1/2)

• Broad bandwidth – Up to 134.4 Mbit/s in 28 MHz channel (in 2-66 GHz)

» 32Mb/s - 134.4Mb/s (>=20MHz per channel) » 1.25/2.5/5/10/14/20/25/28MHz per channel (3.5MHz/7MHz)

• Supports multiple services simultaneously with full QoS – Efficiently transport IPv4, IPv6, ATM, Ethernet, etc. – Wireless transportation system.

• Bandwidth on demand (frame by frame) – Similar to HIPERLAN Type II (frame-based protocol) and DOCSIS – Centralized control

• MAC designed for efficient used of spectrum • Comprehensive, modern, and extensible security

()tensions to mobility are coming next.

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Features (2/2)

• Supports multiple frequency allocations from 2-66 GHz in 802.16 (10-66GHz) , 802.16a (2-11GHz) and 802.16e (<6GHz) and 700MHz

– Single carrier (SC) for line-of-sight situations – OFDM and OFDMA (MC) for non-line-of-sight situations

» OFDM : orthogonal frequency division multiplexing » OFDMA : orthogonal frequency division multiple access

• OFDMA = 1.25 MHz, 2.5, 5, 10, 14 and 20 MHz channels

• Access schemes: – TDD (time division duplex) and FDD (frequency division duplex)

• Link adaptation: Adaptive modulation and coding • Point-to-multipoint (star) topology and mesh network extension • Support for adaptive antennas and space-time coding (in 802.16a) • Extensions to mobility. (IEEE 802.16e started from Jan. 2003

and declared in 2005)

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TDMA/OFDM/OFDMA

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Point-to-Multipoint configuration

• Two components – Subscriber Stations (SSs)

» SS typically serves a building (business or residence) – Base Station (BS)

» connected to public networks » BS serves Subscriber Stations » provide SS with first-mile(or last mile) access to public networks

• Compared to a Wireless LAN

– Multimedia QoS – Not only contention-based – Connection-oriented – Many more users – Much higher data rates – Much longer distances

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Mesh Topology (defined in 802.16a)

• Dynamic topology – Self-organizing network – More complicated

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Relay Topology (defined in 802.16j)

Mobile Multihop Relay

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Relay Topology (defined in 802.16j)

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Adaptive modulation and coding

Source : WiMAX Forum

Full featured Standard

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WiMAX Forum

• WiMAX (Worldwide Interoperability for Microwave Access)

– Like WECA in IEEE 802.11 WLAN • Mission:

– To promote deployment of BWA by using a global standard and certifying interoperability of products and technologies.

• Principles: – Support IEEE 802.16x – 2-66 GHz (16a : 2-11GHz, 16 : 10-66GHz and 16e <6GHz) – Propose access profiles for the IEEE 802.16 standard – Guarantee known interoperability level – Open for everyone to participate

• Developing & submitting baseline test specs

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WiMAX Evolution

Source : Siemens, 2004 802.16j relay

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IEEE 802.16 vs. ETSI • Frequent communications between 802.16 WG and ETSI

(European Telecom Standards Institute)

• ETSI HIPERACCESS – Above 11 GHz (outdoor , 11- 40GHz, 5Km, 25Mb/s) – ETSI began first, but IEEE finished first – 802.16 has encouraged harmonization

• ETSI HIPERMAN – Below 11 GHz (outdoor) – IEEE began first – Healthy cooperation – Harmonized with 802.16a OFDM

• ETSI HIPERLINK –17GHz (150m, point-2-point) –155Mb/s (OC3) –Irrelative with 802.16

• ETSI HIPERLAN –5GHz (indoor/outdoor) –6-54Mb/s –Irrelative with 802.16

HIPERMAN

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802.16 Standard History

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IEEE 802.16 Standard and amendments • Fixed Broadband Wireless Access (FBWA) Systems • Air Interface (MAC and PHY)

– Band 10-66GHz (ranges 1/2/3 : 10-23.5GHz/23.5-43.5GHz/43.5-66GHz) 25/28MHz per channel

– line-of-sight (LOS) requirement – One PHY

» WirelessMAN-SC (Single Sarrier) – Point-to-Multipoint Topology (Star) – TDD/FDD option with burst profile (depending on SNR) – Completed in October 2001 – Published in April 2002

• Follow up interoperability projects – 802.16c (Profiles): published in Jan 2003 – 802.16.1 (PICS)

» PICS : Protocol Implementation Conformance Statement – 802.16.2 (“10-66GHz Coexistence of FBWA Systems”)

» Focus on 23.5 to 43.5 GHz (local multipoint distribution service (LMDS), millimeter wave, etc.,)

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IEEE 802.16a Standard

• “Medium Access Control Modifications and Additional Physical Layer Specifications for 2–11 GHz”

– Band 2-11GHz – Non-line-of-sight (NLOS) requirement and Multi-path issue – Near-LOS – License-exempt band 5-6 GHz (802.11a and HIPERLAN II) – Three PHYs

» WirelessMAN-SC2 (single carrier) » WirelessMAN-OFDM (multiple carriers with 256-point transform)

• is mandatory for license exempt bands » WirelessMAN-OFDMA (multiple carriers with 2048-point transform)

• Multiple access is provided by addressing a subset of the multiple carriers to individual receivers

• Scalable : 128, 512, 1024 and 2048 – Advanced Antenna Systems (AAS) (optional) – Add mesh network topology (MAC) – provide automatic repeat request (ARQ) – retransmission (MAC) – Completed in November 2002 and Approved April 2003

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IEEE 802.16a Standard

• license-exempt bands below 11 GHz – The PHY and MAC introduce mechanisms such as dynamic

frequency selection (DFS) to detect and avoid interference.

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IEEE 802.16-2004 Standard

• IEEE Std 802.16™-2004 – “Air Interface for Fixed Broadband Wireless Access

Systems” - IEEE 802.16d – Approved 24 June 2004 – This standard revises and consolidates IEEE Std 802.16-

2001, IEEE Std 802.16a™-2003, and IEEE Std 802.16c™-2002.

• IEEE Std 802.16f – 16-2004 MIB

• IEEE Std 802.16i

– 16e-2005 MIB (baseline only)

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IEEE 802.16e

• “Amendment for Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands”

– Focus on 2-6GHz (700MHz is considered now)

– 1.25-20MHZ per channel – Enhance OFDMA PHY (w/ subchannelisation)

• Data rate – 10Mhz/channel, OFDMA-64QAM provides 30Mbps

• Max. moving speed : 120km/h (vehicle) • Range : several Kms • Chip appear in 2006 • vs. IEEE 802.20

– Below 3.5GHz – Max. moving speed : 250Km/h (high-speed train) – vs. 3G

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Mobile WiMAX Release 2.0

• Release 2.0 is based on the IEEE 802.16m System Requirements Document

• 802.16m mirrors IMT-Advanced Requirements – Key Performance Targets are:

» Increased DL/UL peak channel & user data rate » 2x DL spectral efficiency of Release 1.0 (2.6 bps/Hz) » 2x cell-edge DL user throughput of Release 1.0 (0.09 bps/Hz) » 2x UL spectral efficiency of Release 1.0 (1.3 bps/Hz) » 2x cell-edge UL user throughput of Release 1.0 (0.05 bps/Hz) » Reduction of the connection setup, RAN delay, & handover interruption time » >60 concurrent sessions per MHz per sector for the adaptive multi-rate (AMR)

12.2 kbps speech codec » Multi-Carrier support for contiguous or non-contiguous channels (up to 100

MHz operating BW with band aggregation) » Mobility support up to 500 km/hr

• Mobile WiMAX Rel 2.0 is backwards compatible with Rel 1.5 and Rel 1.0

35

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IEEE 802.16m

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Logical network reference model, control plane

IB and A interfaces : Transport protocol is not specified

802.16e-2005 NCMS

Network Control and Management System (NCMS) Authentication Service Agency (ASA)

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Network Model

Source : Intel IDF

MS

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MS Mode Transition • Three Modes:

– Idle mode » allows an MS to become periodically available for DL broadcast traffic

without registration at a specific BS » MS traverses an air link environment populated by multiple BSs » allows the MS to conserve power and operational resources (such as

CID, SFID, periodic ranging…) » Listen MOB_PAG-ADV with Paging Controller ID » May perform Idle Mode Location Update Process

– Normal mode (Active mode) » MS transmits and receives packets to/from a BS.

– Sleep mode » to minimize an MS power usage and decrease usage of serving BS air

interface resources by pre-negotiated periods of absence from the serving BS air interface.

» Listen MOB_TRF-IND

• Sleep Mode operation is defined between MS and BS only – NCMS does not need to manage Sleep Mode of subscriber

• NCMS only manages MS in Normal Operation and Idle Mode

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MS Mode Transition (BS view)

Hold mode

Active mode

Park mode Bluetooth

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MS Mode Transition (NCMS view)

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Handover (HO)

• An mobile station (MS) migrates from the air-interface provided by one BS to the air interface provided by another BS

• Backbone network: – Similar to Distribution System (DS) defined in 802.11 WLAN – connect BSs – outside the scope of this standard

• Two HO variants:

– break-before-make HO: service with the target BS starts after a disconnection with the previous serving BS.

– make-before-break HO: service with the target BS starts before disconnecting to the previous serving BS.

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Handover (HO)

• Two HO methods: – Macro diversity handover (MDHO)

» migrate to the air-interface provided by other one or more BSs. » diversity combining on uplink and downlink at MS/BSs

– Fast BS switching (FBSS) » fast switching mechanism to improve link quality » MS is only TX/RX data to/from one active BS (anchor BS) at any

given frame. » The anchor BS can change from frame to frame depending on the

BS selection scheme. • Diversity set:

– contains a list of active BSs to the MS. – is applicable to MDHO and FBSS.

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BS Terms Defined in 802.16e

• Neighbor BS: – whose downlink transmission can be received by MS

• Serving BS: – MS has most recently completed registration at initial network-

entry or during a handover (HO) • Target BS:

– intends to be registered with at the end of a handover (HO) • Active BS:

– is informed of the MS capabilities, security parameters, service flows and full MAC context information.

– For macro diversity handover (MDHO), the MS TX/RX data to/from all active BSs in the diversity set.

– All involving BSs during HO • Anchor BS:

– The MS is registered, synchronized, performs ranging and monitors the downlink (DL) for control information.

– For FBSS supporting MS, this is the serving BS that is designated to transmit/receive data to/from the MS at a given frame

– Play the role of active BS, serving BS and Target BS.

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ID Terms Defined in 802.16e • Paging Controller ID (48-bit : MAC address of BS)

– is a logical network identifier – For the serving BS or other network entity retaining MS service and

operational information – For administering paging activity for the MS while in Idle Mode – Paging Controller ID = BSID when BS is Paging Controller

• Paging Group ID (16-bit : Cellular Network) – One or more logical affiliation grouping of BSs

• Serving BSID (48-bit) (24 : operator ID) – Used for Handover

• HOID (8-bit) – Handover Transaction ID

• Service Level Prediction Index (2-bit) – Predict capability of supporting service flows

• Power_Saving_Class (6-bit) – Associate with sleep parameters

• Power Saving Class Type (2-bit) – Associate with QoS bahavior

• SLPID (10-bit) – Used for traffic indication (directed or bit-mapping) – max. 1024 MS in sleep mode in one BS

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ID Terms Defined in 802.16e

• SPID (2-bit) – Subpacket ID used in HARQ

• Temp BSID (3-bit)

– BS index in BS_NBR-ADV List – Diversity Set Member ID – Used for MDHO and FBSS – Also used for fast Anchor BS selection feedback

• MBS_Zone ID

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Resource Frequency Assignment

• frequency assignment (FA) index – is used in combination with operator specific configuration

information provided to the MS – outside the scope of this standard

• frequency assignment (FA) – a logical assignment of downlink – DL center frequency and channel bandwidth programmed to

the BS

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Mobile WiMAX Roadmap

IEEE802.16REV2

Network Specifications

WiMAX NetworkRelease 1.0

WiMAX NetworkRelease 1.5

WiMAX System ProfileRelease 1.0 (TDD)

Wave 1 and Wave 2

Air InterfaceProfile

Specifications

WiMAX System ProfileRelease 1.5

(TDD & FDD)

Mobile WiMAX Release 1 Certification (W1 & W2)

IEEE802.16(802.16e-2005 +Cor2

802.16g)

WiMAX NetworkRelease 2.0

IEEE802.16m

WiMAX System ProfileRelease 2.0 (TDD & FDD)

Mobile WiMAX Release 1.5 Certification

Mobile WiMAX Release 2.0 Certification

WiMAX ForumCertification

MAC/PHY Standards

In IEEE

WiMAX Forum

IEEE802.16

2006 2007 2008 2009 2010 20112005

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Worldwide License and License Exempt Band

Note : 700MHz allocated for DTV broadcasting is now considered used by 16e WMAN