IEEE 802.16 IEEE 802.16

IEEE 802.16 IEEE 802.16

MAC and PHY Specifications MAC and PHY Specifications

for Broadband WMAN

for Broadband WMAN

Resources

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

Broadband Access to Buildings

• • Wireless Metro Ethernet Wireless Metro Ethernet

–– 802.11 Wireless Ethernet802.11 Wireless Ethernet

• • First/Last mile First/Last mile access

– Fast local connection to network

» 30%-40% Radio/TV pervasion

» 5% internet access

– Target Applications (similar as DSL and CableModemDSL 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

Comparisons of Wireless Standards

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) ^Commercial

Proposed

Mobility

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)

Wireless Metropolitan Area Network

Relay Relay

Application

Fixed WMAN + Mobile WMAN

Source : WiMAX Forum

Network Usage Model

Features (1/2)

• Broad bandwidth

– Up to 134.4 134.4 Mbit/sMbit/s in 28 MHz28 MHz channel (in 22--66 GHz66 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 QoS

– Efficiently transport IPv4, IPv6, ATM, Ethernet, etc.

–– Wireless transportation system.Wireless transportation system

• Bandwidth on demand (frame by frame) (frame by frame)

–– Similar to HIPERLAN Type II (frameSimilar to HIPERLAN Type II (frame-based protocol) and DOCSIS-based protocol) and DOCSIS –– Centralized controlCentralized control

• MAC designed for efficient used of spectrum

• Comprehensive, modern, and extensible security security

()tensions to mobility are coming next.

Features (2/2)

• Supports multiple frequency allocations from 22--66 GHz in 802.16 66 GHz (10(10--66GHz) , 802.16a (266GHz) (2--11GHz)11GHz) and 802.16e (<6GHz) 700MHz(<6GHz) 700MHz

– Single carrier (SC) for line-line-ofof--sightsight situations

– OFDM and OFDMA (MC) for nonnon--lineline--ofof--sightsight 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 mobility (IEEE 802.16e started from Jan. 2003 and declared in 2005)

and declared in 2005)

TDMA/OFDM/OFDMA

Point-to-Multipoint configuration

• Two components

–– Subscriber Stations (SSsSubscriber Stations (SSs))

» SS typically serves a building (business or residence)

–– Base Station (BS) 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

Mesh Topology (defined in 802.16a)

• Dynamic topology

– Self-organizing network – More complicated

Relay Topology (defined in 802.16j)

Relay Topology (defined in 802.16j)

Adaptive modulation and coding

Full featured Standard

WiMAX Forum

• • WiMAX WiMAX (Worldwide Interoperability for Microwave (Worldwide Interoperability for Microwave Access)

Access)

– Like WECAWECA 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

–– 2-2-66 GHz66 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

Wimax Evolution

Source : Siemens, 2004

802.16j relay 802.16j relay

IEEE 802.16 vs. ETSI

• Frequent communications between 802.16 WG and ETSI (European Telecom Standards Institute)

•• ETSI HIPERACCESSETSI HIPERACCESS

–– Above 11 GHz (outdoor , 11-Above 11 GHz (outdoor , 11- 40GHz, 5Km, 25Mb/s)40GHz, 5Km, 25Mb/s) – ETSI began first, but IEEE finished first

– 802.16 has encouraged harmonization

•• ETSI HIPERMANETSI HIPERMAN

–– Below 11 GHz (outdoor)Below 11 GHz (outdoor) – IEEE began first

– Healthy cooperation

– Harmonized with 802.16a OFDM

• ETSI HIPERLINK

––17GHz (150m, 17GHz (150m, point

point--22--point)point) –155Mb/s (OC3)

• ETSI HIPERLAN

––5GHz 5GHz

(indoor/outdoor) (indoor/outdoor) –6-54Mb/s

HIPERMAN

802.16 Standard History

IEEE 802.16 Standard and amendments

• Fixed Broadband Wireless Access (FBWA) Systems

• Air Interface (MAC and PHY)

– Band 10-10-66GHz 66GHz (ranges 1/2/3 : 10-(ranges 1/2/3 : 10-23.5GHz/23.523.5GHz/23.5--43.5GHz/43.543.5GHz/43.5--66GHz) 66GHz) 25/28MHz per channel

25/28MHz per channel

–– line-line-ofof--sight (LOS) requirementsight (LOS) requirement –– One PHYOne PHY

»» WirelessMAN-WirelessMAN-SCSC (Single (Single SarrierSarrier)) –– PointPoint--toto-Multipoint Topology (Star)-Multipoint Topology (Star)

–– TDD/FDD option with burst profile (depending on SNR)TDD/FDD option with burst profile (depending on SNR) – Completed in October 2001

– Published in April 2002April 2002

• Followup interoperability projects

–– 802.16c802.16c (Profiles): published in Jan 2003 –– 802.16.1802.16.1 (PICS)

» PICS : Protocol Implementation Conformance Statement

–– 802.16.2802.16.2 (“10-66GHz Coexistence of FBWA Systems”)

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

IEEE 802.16a Standard

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

– Band 2-2-11GHz11GHz

–– NonNon-line-line--ofof-sight (NLOS) requirement and Multi-sight (NLOS) requirement and Multi--path issuepath issue – Near-LOS

–– LicenseLicense--exempt band 5exempt band 5-6 GHz (802.11a and HIPERLAN II)-6 GHz (802.11a and HIPERLAN II) –– Three Three PHYsPHYs

»» WirelessMANWirelessMAN-SC2 (single carrier)-SC2 (single carrier)

»» WirelessMANWirelessMAN-OFDM (multiple carriers with 256-OFDM (multiple carriers with 256--point transform)point transform)

• is mandatory for license exempt bands

»» WirelessMANWirelessMAN-OFDMA (multiple carriers with 2048-OFDMA (multiple carriers with 2048--point transform)point transform)

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

•• Scalable : 128, 512, 1024 and 2048Scalable : 128, 512, 1024 and 2048

– Advanced Antenna Systems (AAS) (optional) – Add mesh network topology (MAC)mesh network topology (MAC)

– provide automatic repeat request (ARQ) –automatic repeat request (ARQ) – retransmission (MAC)retransmission (MAC) – Completed in November 2002 and Approved April 2003April 2003

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.

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

– 16e2005 MIB (baseline only)

IEEE 802.16e

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

– Focus on

2 2 - - 6GHz 6GHz

– – 1.25- 1.25 -20MHZ per channel 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 will appear in 2006 (orz)

• vs. IEEE 802.20 – Below 3.5GHz

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

Logical network reference model, control plane

IB and A interfaces : Transport protocol is not specified

802.16e

802.16e - - 2005 2005

NCMS NCMS

Network Model

MS

Source : Intel IDF Source : Intel IDF

MS Mode Transition

• Three Modes:

–– Idle modeIdle 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)Normal mode (Active mode)

» MS transmits and receives packets to/from a BS.

–– Sleep modeSleep 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

MS Mode Transition (BS view)

Hold mode Hold mode Active mode Active mode Park mode Park mode

Bluetooth

Bluetooth

MS Mode Transition (NCMS view)

When the MS decides to enter Idle mode ?

When the MS decides to enter Idle mode ?

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-break-beforebefore--make HO: service with the make HO target BStarget BS starts after a disconnection with the previous serving BSserving BS.

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

Handover (HO)

• Two HO methods:

– Macro diversity handover (MDHO)

» migrate to the air-interface provided by other one or moreone or more BSs.

»» diversity combiningdiversity 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 BSone active BS (anchor 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 active BSsBSs to the MS.

– is applicable to MDHO and FBSS.

BS Terms Defined in 802.16e

•• Neighbor BS:Neighbor BS

– whose downlink transmission can be received by MS

•• Serving BS: Serving BS

– MS has most recently completed registration at initial network- entry or during a handover (HO)

•• Target BS:Target BS

– intends to be registered with at the end of a handover (HO)

•• Active BS: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

– All involving BSs during HO

•• Anchor BS: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 BSserving 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.

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)

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

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

Current Activities

• IEEE Std 802.16g (RRM : Radio Resource management)

– System/resource/handover Management – Interoperability

– Expected to be ratified at Jan. 2007 – Draft 4.0

– To be finished

• IEEE Std 802.16h LE (License Exempt)

– Co-existence procedures

– US LE TV Bands, Non--exclusive licensed bands (US: FCC 3650-3700 MHz)

• IEEE Std 802.16j “Mobile Multihop Relay”

– “Mobile Multi-hop Mesh/Relay Networking in IEEE 802.16”

– Chaired by Japanese

• Study Group “Contention-Based Protocol”

– In 16 Licence-Exempt TG

– Topic : 802.11 contention-based protocol affect 802.16 scheduling- based protocol in license-exempt bands

Standard Evolution

16i16i 16j16j

D5D5

16e-16e-20052005

Worldwide License and License Exempt Band

Note : 7

Note : 700MHz allocated for DTV broadcasting 00MHz allocated for DTV broadcasting

MAC Overview

• • Connection Connection - - oriented oriented

• Supports difficult user environments

• High bandwidth, hundreds of users per channel hundreds of users per channel

• • For variable Continuous For variable Continuous and Burst Burst traffic

• Very efficient use of spectrum

• • Protocol Protocol - - Independent core Independent core (ATM, IP, Ethernet, …)

• • Balances Balances between stability of contentionless and efficiency of contention-based operation

• Negotiate the burst profile between sender and receiver

• Flexible QoS QoS offerings

– CBR, rt-VBR, nrt-VBR, BE

• Supports multiple 802.16 PHYs

Protocol Stack

Packet convergence Packet convergence Sublayer

Sublayer (PCS)(PCS)

ATMATM PacketPacket SSCS SSCS

(security

(security sublayersublayer 1616--2004)2004)

Fixed + Mobile Standard

Features

Brief Functions

• Convergence Sublayer (CS)

– Mapping external network data into MAC SDU

» Classifying external network SDU

» Associating to MAC connection ID

» Payload header suppression (PHS)

• Common Part Sublayer (CPS) – Core MAC functionality

» System access

» Bandwidth allocation

» Connection establishment

» Connection maintenance

» Handover and Power amanagement

• Security Sublayer

» Authentication (RSA X.509)

» Security key exchange (3DES)

» Encryption (AES)

• PHY

Service Specific Convergence Sublayer (SSCS)

• The CS performs the following functions:

–– acceptingaccepting higher-layer PDUs from the higher layer – performing classificationclassification of higher-layer PDUs

–– processingprocessing (if required) the higher-layer PDUs based on the classification

–– deliveringdelivering CS PDUs to the appropriate MAC SAP –– receivingreceiving CS PDUs from the peer entity

• Currently, two CS specifications are provided

–– AsyncronousAsyncronous Transfer Mode (ATM) CSTransfer Mode (ATM) CS –– Packet CSPacket CS

»» Such as IP, PPP, Ethernet, etc.,Such as IP, PPP, Ethernet, etc.,

– Other CSs may be specified in the future.

Packet Convergence Sublayer (PCS)

• Packet convergence sublayer (PCS)

– The packet CS resides on toptop of the Common Part Sublayer (CPS)

• The PCS performs the following functions, utilizing the services of the MAC sublayer:

a) ClassificationClassification of the higher-layer protocol PDU into the appropriate connectionconnection

b) SuppressionSuppression of payload header information (optional)(optional) c) DeliveryDelivery of the resulting CS PDU to the MAC SAP

associated with the service flow for transport to the peer MAC SAP

d) ReceiptReceipt of the CS PDU from the peer MAC SAP

e) RebuildingRebuilding of any suppressed payload header information (optional)

(optional)

Packet Process Procedure

• A classifier is a set of matching criteria applied to each packet – It consists of some protocol-specific packet matching criteria

(destination IP address, for example), a classifier priority, and a reference to a CID.

• The service flow characteristics of the connection provide the QoS for that packet

• Several classifiers may each refer to the same service flow.

• Downlink classifiers are applied by the BS to packets and uplink classifiers are applied at the SS.

• a packet fails to match the set of defined classifiers. CS/SS shall discard the packet.

Classifier(s Classifier(s))

Packet

Packet CID CID

PHSIPHSI mapper mapper

SFID

SFID

mapper mapper

SFID/PHSI (sender) SFID/PHSI (sender)

PHS ruler PHS ruler

SFID

SFID SFID SFID

QoSQoS

Parameters Parameters (used in (used in scheduler) scheduler)

Object model

• Each object has a number of attributes

– the attribute names that uniquely identify it are underlined.

– Optional attributes are denoted with brackets.

Common Part Sublayer (CPS)

• The MAC CPS provides the core MAC functionality of system access, bandwidth allocation, connection

establishment, and connection maintenance:

a) System AccessSystem Access

b) Bandwidth Request/AllocationBandwidth Request/Allocation

c) Connection Establishment/MaintenanceConnection Establishment/Maintenance e) Quality of Service (Quality of Service (QoS)QoS)

Security Sublayer

• The security sublayer providing a) a) authentication authentication

b) b) secure key exchange secure key exchange

c) c) Encryption Encryption

• Two component protocols

– Encapsulation protocol

» Cryptographic suites

– Privacy and Key management protocol (PKMv1/v2)

» Create and exchange Traffic Encryption Key (TEK) – PKM Identifier (one byte)

» SS uses the identifier to match a BS response to the SS requests.

» In PKMv1, only SS keeps track of the identifier. (w/o mobility)

» In PKMv2, both SS and BS keep track of the identifier. (w/

mobility)

Classifications

• A MAC SDU is mapped onto a particular connection for transmission between MAC peers

– According to protocol-specific packet matching criteria (e.g.

destination IP address), classifier priority and a reference to a CID (connection ID)CID (connection ID)

» creates an association with the service flow ID (SFID) 32 bitsservice flow ID (SFID) 32 bits

service flow ID service flow ID

(SFID) (SFID) Conn. ID Conn. ID

(CID) (CID)

PHS PHS

CID+PHSI CID+PHSI

Classifications

PHS

service flow ID service flow ID

(SFID) (SFID) Conn. ID Conn. ID

(CID) (CID)

Classifications

• A MAC SDU is mapped mapped onto a particular connection for transmission between MAC peers

– according to protocol-specific packet matching criteria (e.g.

IP address), classifier priority and a reference to a CID. SS and BS use multiple classifiers. multiple classifiers

• Each classifier contains a priority field a priority field which determines the search order for the classifier.

– Searching algorithm is similar to policy-based search algorithm (e.g. FirewallFirewall)

• Classifiers can be added by dynamic signaling. dynamic signaling.

• • Simple Network Management Protocol (SNMP)- Simple Network Management Protocol (SNMP) based operations can only view Classifiers, no

add/delete

Payload Header Suppression (PHS)

• For some payload protocols, each payload consists of an 8 8 - - bit bit payload header suppression index payload header suppression index

(PHSI)

(PHSI) followed by the actual payload.

– A value of zero in the PHSI indicates no payload header suppression has been applied to the PDU. Otherwise, the value in the index identifies the

rules rules

8-8-bitbit

PHSI denotes the payload header PHSI denotes the payload header

MAC header MAC header

Payload Header Suppression (PHS)

• If PHS is enabled at MAC connection, each MAC SDU is prefixed with a PHSI, which references the Payload Header Suppression Field (PHSF).

• The classifier uniquely maps packets to its associated PHS Rule.

• The receiving entity uses the CID and the PHSI to

restore the PHSF. (CID+PHSI PHSF/PHSM/PHSS)

• When a classifier is deleted, any associated PHS rule

shall also be deleted.

• PHS

operation

Payload Header Suppression (PHS) Rule

•• Payload header suppression valid (PHSV)Payload header suppression valid (PHSV) : option to verify or not verify the payload header before suppressing it

•• Payload header suppression mask (PHSM)Payload header suppression mask (PHSM) option to allow select bytes not to be suppressed.

– Such as IP sequence numbers should not be supressedIP sequence numbers should not be supressed

•• Payload header suppression size (PHSS)Payload header suppression size (PHSS)

•• Payload header suppression field (PHSF)Payload header suppression field (PHSF)

•• Payload header suppression index (PHSI)Payload header suppression index (PHSI)

•• Service flow ID (SFID).Service flow ID (SFID)

• PHS rules are indexed by the combination of (SFID, PHSI)

• Preconfigured header format or higher-level signaling protocols are outside the scope of specification

PHS with masking

A,C,E are compressed A,C,E are compressed Only sends B and E Only sends B and E

PHS Rules

• The BS shall define the PHSI when the PHS Rule is created

• The SS or BS may define the PHSS and PHSF.

• To change the value of a PHSF on a service flow, a new PHS rule shall be defined

• It is possible to partially specify a PHS rule (in

particular the size of the rule) at the time a service flow is created

– Values of some fields [for example: IP addresses, User Datagram Protocol (UDP) port numbers, etc.] may be

unknown and would be provided in a subsequent DSC as part of the activation of the service flow

– using the “Set PHS Rule” DSC Action

PHS Signaling

• PHS requires the creation of the following three objects:

a)a) Dynamic Service Flow (DSA/DSC/DSD)Dynamic Service Flow (DSA/DSC/DSD) – Addition/Change/Deletion

b) Classifier b) Classifier c) PHS rule

c) PHS rule (PHSI is assigned by BS)

Connection ID (CID)

• A unidirectional mapping between BS and SS MAC peers for the purpose of transporting a service flow’s traffic

• Connections are identified by a connection identifier (CID)

• All traffic is carried on a connection, even for service flows that implement connectionless protocols

• • CID CID maps to a service flow identifier (SFID), maps to a service flow identifier (SFID), which defines the Quality of Service ( Quality of Service ( QoS QoS ) ) parameters parameters of the service flow associated with that connection.

• • Security associations ( Security associations ( SAs SAs ) ) also exist between

keying material and CIDs.

Connection ID (CID)

• Connections are identified by a 16-bit CID

• At SS initialization, three management connections in three management connections each direction (uplink and downlink) shall be

established between the SS and the BS.

– The basic connectionbasic connection is used for exchanging short, timeshort, time-- urgent

urgent management messages.

» such as DBPC-REQ/RSP : Downlink Burst Profile Change Req/Rsp, RNG-REQ/RSP : Ranging Req/Rsp

– The primary management connectionprimary management connection is used for

exchanging longer, more delay tolerantlonger, more delay tolerant MAC management messages.

» Such as DSA/DSC/DSD_REQ/RSP/ACK, REG_REQ/RSP – The Secondary Management ConnectionSecondary Management Connection is used for

transferring delay tolerant, standards based DHCP, TFTP, delay tolerant SNMP, etc., management messages. (IP-based packets)

Connection ID (CID)

• BS returns Basic CID and Primary CID to SS via RNG-RSP messages.

• BS returns Secondary CID to SS via REG-RSP messages (optional).

• • The same CID value is assigned to both members The same CID value is assigned to both members (uplink and downlink) of each connection pair.

(uplink and downlink) of each connection pair.

• Many higher higher -layer - layer sessions may operate over the sessions

same wireless CID.

Connection ID (CID)

Unfragmented

Unfragmentedfor managementfor management

CIDs

802.16e 802.16e

Unfragmented

Unfragmentedfor managementfor management fragmentable fragmentable

Multicast and Broadcast Connections

• Any available traffic CID value may be used for the service

• SSs do not know its is multicast/broadcast Connections (MBS only from the BS view)

• ARQ is not applicable to multicast connections.

• If a downlink multicast connection is to be encrypted, each SS participating in the connection shall have an additional security association (SA)

• Issue : MBS in 802.16e

Envelopes

dynamic authorization model dynamic authorization model

authorized “envelope”

Setup by BS

provisioned authorization model provisioned authorization model

Service Flow Addition 3 3 - - way handshaking way handshaking

SS-initiated DSA BS-initiated DSA

Service Flow Change

SS-initiated DSC BS-initiated DSC

provisioned provisioned

If no CID, allocates If no CID, allocates

oneone

QoS (16e-2005)

• Global service flows

– Global service class names and associated AuthorizedQoSParamSets

– Global service class names are employed as a baseline convention for communicating AuthorizedQoSParamSet or AdmittedQoSParamSet

– Different from service class name (in 802.16-2004) 1. may not be modified by BS

2. remain consistent among all BS

3. rules-based naming system whereby the global service class name itself contains referential QoS Parameter codes.

• composite name parsed in eight information fields of format ISBRLSPTR (ISTBRLSPR)

ISBRLSPTR (ISTBRLSPR), elements reference extensible look- up tables.

Global service flow class name (2005)

Global service flow class name (2005)

• parameters

– Uplink/Downlink indicator

– Maximum sustained traffic rate

» peak information rate

» does not include transport, protocol, or network overhead

» specifies only a bound, not a guarantee that the rate is available.

» The algorithm for policing this parameter is left to vendor differentiation and is outside the scope of the standard.

– Traffic Indication Preference – Maximum traffic burst

– Minimum reserved traffic rate – Maximum latency

– SDU indicator

» fixed-length or variable-length

Rate

Delay

MAC Protocol

MAC overview

• Subscriber stations share the uplink to the BS on a demand basis.

• Four different types of uplink scheduling mechanisms

– Unsolicited bandwidth grants (CBR) – Polling (unicast polling)

» guarantees applications receive service on a deterministic basis (delay tolerant services)

– Contention procedures

» contention may be used to avoid individual polling of SSs that have been inactive for a long period (multicast/broadcast polling) – Bandwidth stealing

» a portion of the bandwidth allocated in response to a bandwidth request for a connection to send another bandwidth request (6 bytes) rather than sending data

– Piggyback (via grant subheader ; w/o scheduling) (2 bytes)

MAC overview

• Service flows provide a mechanism for uplink and downlink QoS management.

– In particular, they are integral to the bandwidth allocation process.

– An SS requests uplink bandwidth on a per connection basis (implicitly identifying the service flow).

– Bandwidth is granted by the BS to an SS as an aggregate of grants in response to per connection requests from the SS.

Scheduling services

• Each connection is associated with a single data service.

• Each data service is associated with a set of QoS parameters.

– Managed using the DSA and DSC message dialogs.

• Four services are supported in 802.16802.16--20042004 – Unsolicited Grant Service (UGS),

– Real-time Polling Service (rtPS),

– Non-real-time Polling Service (nrtPS), and – Best Effort (BE).

• Five services are supported in 802.16e802.16e--20052005 – 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)

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

• mandatory QoS service flow parameters

– Maximum Sustained Traffic Rate – Maximum Latency

–– Tolerated JitterTolerated Jitter

– Request/Transmission Policy

– (option) Minimum Reserved Traffic Rate parameter

» If present, equals to Maximum Sustained Traffic Rate parameter.

• • In 802.16e, In 802.16e,

–– UGS is able to support variable lengthUGS is able to support variable length PDUsPDUs.. –– Maximum Sustained Traffic RateMaximum Sustained Traffic Rate is removedis removed

–– Add UAdd Unsolicited Grant Interval nsolicited Grant Interval andand SDU size (if fixed)SDU size (if fixed)

Unsolicited Grant Service (UGS)

• The BS shall provide Data Grant Burst IEs to the SS at periodic intervals based upon the Maximum Sustained Traffic Rate of the service flow.

• The Grant Management subheader is used to pass

status information from the SS to the BS regarding the state of the UGS service flow.

– Slip Indicator (SI) bit : set when service flow has exceeded its transmit queue depth

– Poll-me (PM) bit : is used to request to be polled for a different, non-UGS connection.

– Request : contention-free access

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.

• mandatory QoS service flow parameters

– Minimum Reserved Traffic Rate – Maximum Sustained Traffic Rate –– Maximum LatencyMaximum Latency

– Request/Transmission Policy

» SS uses only unicast poll request opportunities in order to obtain uplink transmission opportunities

» use unsolicited Data Grant Burst Types for uplink transmission as well

» contention-free manner

• In 802.16e,

– Add Traffic priority and Unsolicited Polling Interval

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

• mandatory QoS service flow parameters

– Minimum Reserved Traffic Rate – Maximum Sustained Traffic Rate – Traffic Priority

– Request/Transmission Policy

» unicast poll : BS typically polls nrtPS CIDs on an interval on the order of one second or less

» timely unicast request opportunities : contention access

» unsolicited Data Grant Burst Types

Best Effort (BE)

• support data streams for which no minimum service level is required and therefore may be handled on a space-available basis.

• mandatory QoS service flow parameters

– Maximum Sustained Traffic Rate – Traffic Priority

– Request/Transmission Policy

» contention request opportunities

» Piggyback

» Bandwidth steal

» Polling

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.

• QoS parameters (combines UGS and RT combines UGS and RT- -VR VR)

– Maximum Latency – Tolerated Jitter

– Minimum Reserved Traffic Rate – Maximum Sustained Traffic Rate – Traffic Priority

– Request/Transmission Policy – Unsolicited Grant Interval

Outbound transmission scheduling

• is performed by

–– BS for downlink,BS for downlink, –– SS for uplinkSS for uplink

• the following items are taken into account for each active service flow:

– The scheduling service specified for the service flow.

– The values assigned to the service flow’s QoS parameters.

– The availability of data for transmission.

– The capacity of the granted bandwidth

QoS Scheduler

Outbound Transmission Scheduling

MPDU format

MAC PDU formats

HT=0HT=0 HT=1HT=1

Bandwidth Request Generic

CRC capability is mandatory

for SCa, OFDM and OFDMA PHY layers

6 octets 6 octets

Generic MAC Header

Management frame Management frame

Type encodings (in Generic Header)

Bit mapping Bit mapping

Type bits

Type bits

Bandwidth Request MAC Header

000 : incremental (BS adds the needed quantity of CID) 000 : incremental (BS adds the needed quantity of CID) 001 : aggregate (BS replaces the needed quantity of CID) 001 : aggregate (BS replaces the needed quantity of CID)

Bandwidth Request

• The Bandwidth Request shall have the following properties:

a) length of the header = 6 bytes

b) EC field = 0 (indicating no encryption)

c) CID indicates the connection for which uplink bandwidth is requested.

d) Bandwidth Request (BR) field indicates the number of bytes requested.

e) The allowed types for bandwidth requests are “000” for incremental and “001” for aggregate.

Subheader Types

• Five types of subheaders – Mesh

– Fragmentation

– FASTFEEDBACK_Allocation (MIMO) – Grant Management

– Packing

– Extended subheader field (defined in 16e : (defined in 16e : 11 additional subheaders))

» ESF bit in the Generic MAC header is set

• The subheaders are inserted in MAC PDUs immediately following the Generic MAC header.

– Sequence

» Grant -> Fragmentation

» Extended subheader -> others (defined in 16e)(defined in 16e)

» Mesh -> others

» others -> FastFeedback_allocation

– The Packing and Fragmentation subheaders are mutually exclusive and shall not both be present within the same MAC PDU

MAC header formats in 802.16e

HT EC MAC PDU Type

0 0 Generic MAC headerGeneric MAC headerfor DL and UL

w/ data payload, no encryption (66--bitbit type field)

0 1 Generic MAC headerGeneric MAC header for DL and UL

w/ data payload, w/ encryption (66--bitbit type field)

1 0

DL: This encoding is not defined UL: MAC signaling headerMAC signaling header type Itype I

MAC PDU w/o data payload (33--bitbit type field)

1 1

DL: Compressed/Reduced Private DLCompressed/Reduced Private DL--MAPMAP UL: MAC signaling headerMAC signaling header type II.type II

MAC PDU w/o data payload (11--bitbit type field) Data

Payload

Control No encrypt

(OFDMA only) (OFDMA only)

•• Headers with HT=1 shall not be encryptedHeaders with HT=1 shall not be encrypted

•• EC field is used to distinguish between Feedback MAC header EC field is used to distinguish between Feedback MAC header (UL) / Compress MAP (DL), and all other type headers

(UL) / Compress MAP (DL), and all other type headers

Generic MAC header format

ESF : Extended subheader field. (for UL/DL) (0): the extended subheader is absent.

(1): the extended subheader is present and will follow the GMH

All extended subheaders are not encrypted

Extended

Extended subheaders subheaders

3-bit Type Field in MAC Signaling Header Type I

• 000 : BR incremental

• 001 : BR aggregate

• 010 : PHY channel report

• 011 : BR with UL Tx Power Report (piggyback)

• 100 : BR and CINR report (piggyback)

• 101 : BR with UL sleep control (piggyback)

• 110 : SN Report

• 111 : CQICH allocation request

• • Support of Support of subheaders subheaders is negotiated during is negotiated during registration (REG

registration (REG - - REQ/RSP) REQ/RSP)

3-bit Type Field in MAC Signaling Header Type I

• 000 : BR incremental

• 001 : BR aggregate

• 010 : PHY channel report

• 011 : BR with UL Tx Power Report (piggyback)

• 100 : BR and CINR report (piggyback)

• 101 : BR with UL sleep control (piggyback)

• 110 : SN Report

• 111 : CQICH allocation request

• • Support of Support of subheaders subheaders is negotiated during is negotiated during registration (REG

registration (REG - - REQ/RSP) REQ/RSP)

MPDU Transmission

long Ethernet packet

long Ethernet packet Short ATM cells

Concatenation

• • Mandatory Mandatory capability

• Multiple MAC PDUs may be concatenated into a

single transmission in either the uplink or downlink directions.

• each MAC PDU is identified by a unique CID

Bandwidth stealing Bandwidth stealing

Packing

• The capability of unpacking is mandatory. mandatory

• • pack multiple MAC pack multiple MAC SDUs SDUs into a single MAC PDU. into a single MAC PDU

– Differs from concatenation

• Packing makes use of the connection attribute indicating whether the connection carries fixed fixed - - length or variable

length or variable- -length packets. length packets.

• The construction of PDUs varies for ARQ and non- ARQ connections with respect to packing and

fragmentation syntax

Packing for non-ARQ connections

• Packing fixed-length MAC SDUs

– the Request/Transmission PolicyRequest/Transmission Policy shall be set to allow

packing and prohibit fragmentation, and the SDU size shall be included in DSA-REQ message when establishing the connection

– If the MAC SDU size is n bytes, the receiver unpacks simply by knowing that the length field in the MAC header will be n×k+j, where k is the number of MAC SDUs packed into the MAC PDU and j is the size of the MAC header and any

prepended MAC subheaders.

– no added overhead

Packing for non-ARQ connections

• Packing variable-length MAC SDUs

– indication of where one MAC SDU ends and another begins.

– the MAC attaches a Packing subheader (PSH) to each MAC SDU

– unfragmented MAC SDUs and MAC SDU fragments may both be present in the same MAC PDU

Packing for non-ARQ connections

• Simultaneous fragmentation and packing allows efficient use of the airlink

• when a Packing subheader (PSH) is present, the

fragmentation information for individual MAC SDUs or MAC SDU fragments is contained in the

corresponding Packing subheader.

• Else (If no PSH is present), the fragmentation

information for individual MAC SDU fragments is

contained in the corresponding Fragmentation

subheader (FSH)

Packing for non-ARQ connections

PSH PSH

PSH PSH

FSH FSH

Packing for ARQ-enabled connections

• Each of the packed MAC SDU or MAC SDU fragments or ARQ feedback payload requires its own Packing subheader

• A MAC SDU may be partitioned into multiple fragments that are then packed into the same MAC PDU for the first transmission.

• MAC PDUs may have fragments from the same or

different SDUs, including a mix of first transmissions and retransmissions.

• The 11-bit BSN and 2-bit FC fields uniquely identify each

fragment or non-fragmented SDU.

Hybrid-ARQ

• Optional part and may be support for OFDMA PHY

• The parameters are negotiated during initialization procedure

• Each H-ARQ packet is encoded according the PHY specification at the FEC block level

– Subpacket identifier (SPID) is used to distinguish the four subpackets

– A BS can send one of the subpackets in a burst transmission – When SS received more than one subpackets, it tries to decode

from ever-received subpackets

– If transmission failure, SS sends a NACK, BS transmit one more from the four subpackets

Payload Type

• Payload Type indicates whether MAC subheaders (Packing/Fragmentation/Grant

(Packing/Fragmentation/Grant) present or not.

packing/

packing/

fragmentation fragmentation

packing/

packing/

fragmentation/

fragmentation/

grant grant//

p+gp+g// f+gf+g

MAC Subheader

• Three types of MAC subheaders may be present.

– The grant management subheadergrant management subheader is used by an SS to convey bandwidth management needs to its BS.

– The fragmentation fragmentation subheadersubheader contains information that indicates the presence and orientation in the payload of any fragments of SDUs. (e.g. long Ethernet packet)

– The packing subheaderpacking subheader is used to indicate the packing of multiple SDUs into a single PDU. (e.g. ATM cells)

Fragmentation Subheader format

Grant Subheader format (2004)

(incremental mode only

(incremental mode only –– 16bits vs. 19 bits)16bits vs. 19 bits)

set when service flow has exceeded its transmit queue depth is used to request to be polled for a different, non-UGS connection

Grant Subheader Format (2005)

Frame latency indication Frame latency

incremental Slip Indicator

Packing Subheader format

Extended Subheader Format

total length in bytes

Extended Subheader Format (DL) (DL)

The support of each extended subheader is negotiated between BS and MS as part of the registration dialog (REG-REQ/RSP).