1. WiMAX_NWG_Stage2 & Stage3. WiMAX Forum The WiMAX Forum is a nonprofit organization formed in 2001 to enhance the compatibility and interoperability.

1. WiMAX_NWG_Stage2 & Stage3

WiMAX Forum

The WiMAX Forum is a nonprofit organization formed in 2001 to enhance the compatibility and interoperability of equipment based on the IEEE 802.16 family of standards

WiMAX Forum_Network Working Group (NWG) define

Stage 1: use case scenarios and service requirements and defined along with Service Provider Working Group

Stage 2: Architecture Tenets, Reference Model and Reference Points

Stage 3: Detailed Protocols and Procedures

WiMAX Working Group

‧Application Working Group (AWG)

‧Certification Working Group (CWG)

‧Evolutionary Technical Working Group (ETWG)

‧Global Roaming Working Group (GRWG)

‧Marketing Working Group (MWG)

WiMAX Working Group

‧Network Working Group (NWG)

‧Regulatory Working Group (RWG)

‧Service Provider Working Group (SPWG)

‧Technical Working Group (TWG)

Relationship between the scopes of WiMAX NWG and 802.16

From IEEE 802.16 to WiMAX NWG build an interoperable broadband wireless

network. Interoperable networks involve end-to-end service

such as IP connectivity and session management, security, QoS, and mobility.

WiMAX Network Reference Model(1/2)

Decomposed ASN into BS and ASN GW entities

Entities of the WiMAX Network Reference Model (1/2)

ASN: Access Serving Network

Logical representation of the functions of a NAP, e.g. 802.16 interface network entry and handover Radio Resource Management & Admission ctrl. L2 Session/mobility management QoS and Policy Enforcement Foreign Agent (FA) Forwarding to selected CSN

Entities of the WiMAX Network Reference Model (2/2)

CSN: Connectivity Serving Network

Logical representation of the functions of a NSP, e.g. Connectivity to the Internet, ASPs Authentication, authorization and accounting IP address management L3 Mobility and roaming between ASNs Policy & QoS management based on a SLA

Network Reference point (1/2)

R1: Reference point between MS and BS: implements IEEE 802.16e-2005.

R2: Reference point between MS and ASN-GW or CSN: logical interface used

for authentication, authorization, IP host configuration and mobility management.

R3: Reference point between ASN and CSN: supports AAA, policy enforcement,

and mobility –management capabilities. Implements tunnel between ASN and CSN.

R4: Reference point between ASN and ASN: used for MS mobility across ASNs.

Reference point (2/2)

R5: Reference point between CSN and CSN: used for

internetworking between home and visited network. R6:

Reference point between BS and ASN: implements intra-ASN tunnels and used for control plane signaling.

R7: Reference point between data and control plane in ASN-

GW: used for coordination between data and control plane in ASN-GW.

R8: Reference point between BS and BS: used for fast and

seamless handover.

WiMAX Network Reference Model(2/2)

ASN Network & GW

ASN-GW Reference model

Internetworking with 3GPP

Scope WiMAX-3GPP Interworking

refers to the integration of a WiMAX Access Network to an existing 3GPP core network.

3GPPCard

WiMAXCard

UE

Loosely-CoupledInternetworking

3GPP AccessNetwork

RNC

GCSN

SGSN

3GPP CoreNetwork

WAG

PDGBilling Server

Home AAA

Internet

Home Agent

WiMAX NetworkService Provider

Local AAA

WiMAX Base Stations

WiMAX ASN

802.16e network entry

In a WiMAX network, a full network entry includes four steps:a. Network Discovery and

Selection

b. Access Authentication

c. Connection Setup

d. Data Transfer

802.16 TDD Frame Structure

Frame Control

DATA

Contention Slot

DATA

Downlink Subframe Uplink Subframe

DL-MAP

TDD Frame Structure

UL-MAP

DCD

UCD

Contention RequestBandwidth Request

Time Slot

Network entry A WiMAX subscriber station has to complete the

network entry process , in order to communicate on the network.

Steps: Scan for DL channel and establish synchronization with the BS Obtain transmit parameters (form UCD message) Perform initial ranging Negotiate basic capabilities Authorize MS and perform key exchange Establish IP connectivity Establish time of day Transfer operational parameters optional Set up connections

a)Downlink Channel Synchronization: When an SS wants to communicate on a WiMAX

network, it first scans for available channels in the defined frequency list. On finding a DL channel, it tries to synchronize at the PHY level using the periodic frame preamble. Information on modulation and other DL and UL parameters is obtained by

observing the DL Channel Descriptor (DCD) and the UL channel descriptor (UCD) of the DL channel.

Ranging(1/2)

b) Initial Ranging: An SS starts an Initial ranging process by sending a

ranging request MAC message using the minimum transmission power. If no response is received from the BS, the SS resends the message on a subsequent frame using a higher transmission power. The response either indicates power and timing corrections that the SS must make or indicates success.

Purpose: The process by which the SS and BS maintain the quality of RF

communication link between them.

Ranging(2/2)

Periodic ranging Allows SS to adjust transmission parameters and

maintain uplink communication with the BS.

c) Exchanging Capabilities: After successful completion of the initial ranging step, the

SS sends capability request message indicating the supported modulation level, coding scheme and rates and duplexing methods.

d) Authentication: After capability negotiation, the BS authenticates the SS,

determines the ciphering algorithm to be used, and sends an authentication response to the SS.

e) Registration: After authentication, the SS sends a registration request

message to the BS and the BS sends a registration response.

f) IP Connectivity: After registration, the SS gets the IP address via DHCP.

The SS also downloads other operational parameters using TFTP.

g) Connection Creation: After completing the IP connectivity step, transport connections are

created. For preprovisioned service flows, the BS sends a dynamic service flow addition request message to the SS and SS confirms the creation of connection. For non-preprovisioned service flows, connection creation is initiated by the SS by sending a dynamic service flow addition request message to the BS. The BS responds with the confirmation.

Network Discovery and Selection

NAP discovery NSP discovery NSP Enumeration and selection ASN attachment based on NSP Selection

NSP Discovery

ASN Attachment based on NSP Selection

Connection setup

The ASN setup Access Authentication Binding of MS flow to intra-ASN DATA PATH MIP req / resp

PMIP4 / CMIP4 / CMIP6 MIP tunnel

Connection setup procedure( DHCP proxy )

Connection setup procedure( CMIPv4 )

Connection Setup Procedure (CMIP6 )

Mobility management

The WiMAX mobility solution consists of two mobility levels Intra-ASN mobility

ASN Anchored Mobility inter-ASN mobility

ASN-anchor (based on profile A & C) CSN Anchored Mobility

ASN Anchored Mobility Management(1/4)

ASN Anchored Mobility Management is defined as mobility of an MS not involving a CoA update (MIP re-registration)

ASN anchor Mobility (2/4)

ASN anchored mobility (3/4)

CSN Anchor mobility( R3-mobility )

Re-anchoring of the current FA to a new FA and the consequent binding updates to update the upstream and downstream data forwarding paths.

Authentication, Authorization and Accounting

The WiMAX AAA framework is based on IETF specifications. The term AAA is used to refer to the AAA protocols, Radius or Diameter.

The AAA framework provides the following services to WiMAX: Authentication Services

These include MS, user, or combined MS and user authentication. Authorization Services

These include the delivery of information to configure the session for access, mobility, QoS and other applications.

Accounting Services These include the delivery of information for the purpose of billing

(both prepaid and post paid billing) and information that can be used to audit session activity by both the home NSP and visited NSP.

Accounting Architecture

QOS

IEEE 802.16 MAC is connection oriented. Each connection, upon establishment, subscribes to one of the scheduled services

Resource allocation, admission, and scheduling is controlled the base station

QoS Functional Elements

Service Flow Management (SFM) responsible for the creation,

admission, activation, modification and deletion of 802.16 service flows.

Service Flow Authorization (SFA) Evaluate any service request

against user QoS profile. AF: Application Function

e.g., SIP Proxy PF: Policy Function

Maintained information includes H-NSP's general policy rules

LPF: Local Policy Function enforce admission control based

on available resources

Handoff Function

The following types of handovers are supported by the handoff function. Mobile initiated handovers at a given serving Base-Station. Network initiated handovers. FBSS and MDHO (possibility to support MDHO SHOULD

be further discussed) The Handoff Function can be further classified by its

roles in handover operation as follows Serving HO Function Relaying HO Function Target HO Function

IEEE 802.16e Handoff Process

The stages of Handoff Process Handoff decision stage Handoff planning stage Handoff execution stage

HO Function Network Transaction

Reference

Wimax forum WiMAX End-to-End Network Systems Architecture (Stage 3: Detailed Protocols and Procedures)

Wimax forum WiMAX End-to-End Network Systems Architecture (Stage 2)