Transcript CH4. WiMAX core Netrork

1. WiMAX_NWG_Stage2 &
Stage3
WiMAX Forum
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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
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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
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From IEEE 802.16 to WiMAX NWG
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build an interoperable broadband wireless
network.
Interoperable networks involve end-to-end service
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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)
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ASN: Access Serving Network
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Logical representation of the functions of a NAP, e.g.
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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)
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CSN: Connectivity Serving Network
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Logical representation of the functions of a NSP, e.g.
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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)
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R1:
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R2:
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Reference point between MS and ASN-GW or CSN: logical interface used
for authentication, authorization, IP host configuration and mobility
management.
R3:
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Reference point between MS and BS: implements IEEE 802.16e-2005.
Reference point between ASN and CSN: supports AAA, policy enforcement,
and mobility –management capabilities. Implements tunnel between ASN
and CSN.
R4:
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Reference point between ASN and ASN: used for MS mobility across ASNs.
Reference point (2/2)
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R5:
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R6:
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Reference point between BS and ASN: implements intraASN tunnels and used for control plane signaling.
R7:
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Reference point between CSN and CSN: used for
internetworking between home and visited network.
Reference point between data and control plane in ASNGW: used for coordination between data and control plane
in ASN-GW.
R8:
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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
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WiMAX-3GPP Interworking
refers to the integration of a
WiMAX Access Network to an
existing 3GPP core network.
Internet
Billing Server
PDG
Home Agent
WAG
Home AAA
3GPP Core
Network
GCSN
WiMAX Network
Service Provider
Local AAA
SGSN
RNC
3GPP Access
Network
Loosely-Coupled
Internetworking
WiMAX ASN
WiMAX Base Stations
3GPP
Card
WiMAX
Card
UE
802.16e network entry
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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
Time Slot
Downlink Subframe
Uplink Subframe
Frame Control
Contention Request
Bandwidth Request
DATA
Contention Slot
UCD
DCD
DATA
UL-MAP
DL-MAP
TDD Frame Structure
Network entry
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A WiMAX subscriber station has to complete the
network entry process , in order to communicate
on the network.
Steps:
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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
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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)
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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:
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The process by which the SS and BS maintain the quality of RF
communication link between them.
Ranging(2/2)
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Periodic ranging
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Allows SS to adjust transmission parameters and
maintain uplink communication with the BS.
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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.
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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.
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f) IP Connectivity:
After registration, the SS gets the IP address via DHCP.
The SS also downloads other operational parameters
using TFTP.
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g) Connection Creation:
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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
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NAP discovery
NSP discovery
NSP Enumeration and selection
ASN attachment based on NSP Selection
NSP Discovery
ASN Attachment based on NSP
Selection
Connection setup
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The ASN setup
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Access Authentication
Binding of MS flow to intra-ASN DATA PATH
MIP req / resp
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PMIP4 / CMIP4 / CMIP6
MIP tunnel
Connection setup procedure
( DHCP proxy )
Connection setup procedure
( CMIPv4 )
Connection Setup Procedure (CMIP6 )
Mobility management
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The WiMAX mobility solution consists of two
mobility levels
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Intra-ASN mobility
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ASN Anchored Mobility
inter-ASN mobility
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ASN-anchor (based on profile A & C)
CSN Anchored Mobility
ASN Anchored Mobility
Management(1/4)
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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 )
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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
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The WiMAX AAA framework is based on IETF specifications.
The term AAA is used to refer to the AAA protocols, Radius or
Diameter.
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The AAA framework provides the following services to WiMAX:
 Authentication Services
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Authorization Services
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These include MS, user, or combined MS and user authentication.
These include the delivery of information to configure the session for
access, mobility, QoS and other applications.
Accounting Services
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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
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IEEE 802.16 MAC is connection oriented. Each
connection, upon establishment, subscribes to one
of the scheduled services
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Resource allocation, admission, and scheduling is
controlled the base station
QoS Functional Elements
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Service Flow Management (SFM)
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Service Flow Authorization (SFA)
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e.g., SIP Proxy
PF: Policy Function
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Evaluate any service request
against user QoS profile.
AF: Application Function
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responsible for the creation,
admission, activation, modification
and deletion of 802.16 service
flows.
Maintained information includes HNSP's general policy rules
LPF: Local Policy Function
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enforce admission control based
on available resources
Handoff Function
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The following types of handovers are supported by
the handoff function.
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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
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Serving HO Function
Relaying HO Function
Target HO Function
IEEE 802.16e Handoff Process
The stages of Handoff Process
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Handoff decision stage
Handoff planning stage
Handoff execution stage
HO Function Network Transaction
Reference
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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)