{教育管理}国立中正大学通�工程学系
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
WiMAX
Worldwide Interoperability for Microwave Access
The Institute of Electrical and Electronics Engineers
(IEEE) 802 mittee ( ).
Orthogonal Frequency Division Multiplexing (OFDM)
(carriers of width of 5MHz or greater can be used )
connectivity at speeds up to 70 Mbps
provide high speed access to about 60 businesses
at T1 speeds.
can serve up to a thousand homes in term of DSL
speed.
History
The initial standard in
2002, operates in the 10-to-66-
GHz frequency band and
requires LOS towers.
The extension, ratified in
March 2003
allows use of 2 to 11 GHz
frequency.
It boasts a 50 km range and
Data transfer rates and doesn't
require LOS transmission.
History
Quality of
service
Interoperability,
with protocols
and test-suite
structures
Fixing things not
covered by
Support for mobile as
well as fixed
broadband (-
2005)
MIB
System/resource/han
dover Management
Interoperability
Relay
Additional standards :
Mobile WiMAX
Mobile Technical Group (MTG) in WiMAX Forum develops the system
profile for Mobile WiMAX system
A Broadband wireless solution
– Fix broadband network
– Mobile broadband network
Signaling
– Orthogonal Frequency Division Multiple Access (OFDMA)
– Scalable OFDMA
Features
High Data Rate
Quality of Service
Scalability
Security
Mobility
WiMAX entity
Two ponents
Subscriber Stations (SSs)Subscriber 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
Scenario
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
Introduction
QoS supporting is a fundamental
part of the WiMAX MAC-layer
design.
How does WiMAX support for
QoS?
Connections
A connection-oriented MAC
architecture
all downlink and uplink connections
are controlled by the serving BS
Each connection is identified by a
connection identifier (CID)
A service flow is a unidirectional
flow of packets
with a particular set of QoS
parameters
is identified by a service flow
identifier (SFID)
The service flow characteristics of
the connection provide the QoS
for that packet
Service flows
parisons of SFID & CID
Service Flow ID (SFID) does not change upon HO
across BSs belonging to a single NAP
SFID shall be set just once when a layer 2 service
flow is originally established, and SHALL NOT be
modified by HOs.
SFID shall be assigned when a new service flow is
set up and shall be maintained as the same value at
the Anchor Data Path Function in spite of HOs.
Connection ID (CID) is defined as temporary in a
particular cell coverage area.
CID shall be refreshed whenever MS moves into a
new cell.
SFID identifies a particular Layer 2 session while CID
specifies a particular logical radio link.
Operation Object
Model
Service Flow
Management
Dynamic Service Change (DSC)
Dynamic Service Delete (DSD)
Dynamic Service Activate (DSA)
NULL
OPERATIONAL
DSD
DSA
DSC
Dynamic Service Flow
Change
Classifier
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
a reference to a CID.
Classifiers can be added by
dynamic signaling
Scheduler
Associate packets into service flow
Define QoS parameter for each service flow
Dynamically establishing QoS-enabled service flows
Associate QoS service flow with logical connections
Classifier
Scheduler
BS MAC Priority
queues
MS1 MAC
MS2 MAC
QoS logical
connections
Service flow
over
QoS connections
Servic
e
flows
Quality of Service
Support
Scheduling services
Four services are supported in -2004
Unsolicited Grant Service (UGS),
Real-time Polling Service (rtPS),
Non-real-time Polling Service (nrtPS), and
Best Effort (BE).
Five services are supported in -
2005
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
INTERNET
VoIP
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.
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
Best Effort (BE)
support data streams for which no
minimum service level is required
and therefore may be handled on
a space-available basis.
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.
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
WiMAX Forum
The WiMAX Forum is a nonprofit organization
formed in 2001 to enhance the patibility and
interoperability of equipment based on the IEEE
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)
Define applications over WiMAX that are necessary to meet core petitive
offerings
Certification Working Group (CWG)
Handles the operational aspects of the WiMAX Forum Certified program.
Evolutionary Technical Working Group (ETWG)
Maintains existing OFDM profiles, develops additional fixed OFDM profiles,
and develops technical specifications for the evolution of the WiMAX
Forum's OFDM based networks from fixed to nomadic to portable, to mobile.
Global Roaming Working Group (GRWG)
Assures the availability of global roaming service for WiMAX networks in a
timely manner as demanded by the marketplace.
Marketing Working Group (MWG)
Promotes the WiMAX Forum, its brands and the standards which form the
basis for worldwide interoperability of BWA systems.
WiMAX Working Group
Network Working Group (NWG)
Creates higher level networking specifications for fixed, nomadic, portable and
mobile WiMAX systems, beyond what is defined in the scope of .
Regulatory Working Group (RWG)
Influences worldwide regulatory agencies to promote WiMAX-friendly, globally
harmonized spectrum allocations.
Service Provider Working Group (SPWG)
Gives service providers a platform for influencing BWA product and spectrum
requirements to ensure that their individual market needs are fulfilled.
Technical Working Group (TWG)
The main goal of the TWG is to develop technical product specifications and
certification test suites for the air interface based on the OFDMA PHY.
Relationship between the scopes
of WiMAX NWG and
From IEEE 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.
Tenets for WiMAX
Network Systems
Architecture
Based on ……
a packet-switched framework
IEEE standard and IETF RFCs
Decoupling of access architecture from
connectivity IP services
Specifying open, published and accepted
standards
SHALL NOT preclude inter-technology handover
SHALL support seamless handovers at up to
vehicular speeds
All-IP Network !
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
WiMAX Network Reference Model
Deposed 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, .
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, .
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 -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 Profile A
Functional View
ASN-GW Reference
model
Link model for Profiles
A &C
Internetworking with
3GPP
Scope
WiMAX-3GPP Interworking
refers to the integration of a
WiMAX Access Network to an
existing 3GPP core network.
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
network entry
In a WiMAX
network, a full
network entry
includes four
stages:
a. Network
Discovery and
Selection
b. Access
Authentication
c. IP Configuration Setup
d. Data Transfer
IP Configuration Setup
Network entry
A WiMAX subscriber station has to plete the
network entry process, in order to municate on
the network.
Steps:
Scan for DL channel and establish synchronization with the BS
Obtain transmit parameters (from 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 municate 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.
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
munication link between them.
When ranging finished, the BS would allocate Basic CID and
Primary management CID to SS
c) Exchanging Capabilities:
After successful pletion of the initial ranging step, the SS
sends capability request message indicating the
supported modulation level, coding scheme and rates
and duplexing methods.
The MS and ASN also SHALL negotiate the PKM
version, PKMv2 security capabilities and authorization
policy including requirements and support for Device
Authentication.
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, with a secondary management CID for IP
configuration
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 pleting 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 Access discovery
NSP Enumeration and selection
ASN attachment based on NSP
Selection
NAP and NSP
Discovery “1” to indicate one or more
NSPs
• As per “ Service Identity Information (SII-ADV) message”, a BS may use the
SII-ADV message to broadcast a list of Network Service Provider (NSP) Identifiers.
• The MS MAY include the Visited NSP ID TLV in the SBC-REQ message to solicit BS
transmittal of the Visited NSP Realm TLV in the SBC-RSP message.
ASN Attachment based on NSP
Selection
MS_1NSP_1.
NSP_4!MS_2NSP_1.
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
Why encryption?
Encryption
a mechanism that
protects data confidentiality
and integrity
plaintext to ciphertext
Encryption
•Encryption is always applied to the MAC PDU payload;
the generic MAC header is not encrypted; some
management messages are not encrypted.
Encryption -- WiMAX
WiMAX uses the Advanced
Encryption Standard () to produce
ciphertext.
Receiver of the ciphertext simply
reverses the process to recover
the plaintext.
Public key infrastructure
The WiMAX -2005 standard uses the Privacy and Key
Management Protocol version 2 (PKMv2) for securely
transferring keying material between the base station and the
mobile station.
PKMv2’s ponents
digital certificates
RSA public-key algorithm
Strong encryption algorithm to perform key exchanges between
SS to BS.
PKMv2 mechanism
Validates user identity and establishes an authorization key (AK)
AK is used to derive the encryption keys, . KEK, CMAC_KEY
Supports device and user authentication between MS and home
CSN (PKMv1 only for device)
Public key infrastructure
PKMv2 supports the use of the (RSA) exchange.
RSA public key exchange
requires that the mobile station establish identity using either a
manufacturer-issued (Device Credential, called Device-Cert) or
an operator-issued credential such as a subscriber identity
module () card (Subscriber Credential, called Subscriber Root
Key, SUBC).
digital certificate contains the mobile station's Public-Key
(PK) and its .
加密資料 (public key)
解密資料 (private
key)
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 bined 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.
ASN security
architecture (1/2)
The mobile station transfers the digital certificate to the
WiMAX network, which then forwards the certificate to a
certificate authority. The certificate authority validates the
certificate, thus validating the user identity.
ASN security
architecture (2/2)
User/Device
Authentication
Protocol layering
Keys in PKMv2
Master Session Key (MSK)
512 bits, generated in EAP
process
Known by AAA peer, AAA server,
and authenticator
Pairwise Master Key (PMK)
160 bits, derived from MSK
Known by authenticator and AAA
peer
Authorization Key (AK)
160 bits, derived from PMK(1+2),
SS MAC, BS ID
Key Encryption Key (KEK)
128 bits, derived from AK, SS
MAC, BS ID
Traffic Encryption Key (TEK)
distributed by the BS
refreshed periodically
encrypted by KEK
Traffic is encrypted / decrypted by
TEK
Device credential
issued by manufacturer
Subscriber credential
issued by operator
Extended Master Session
Key (EMSK)
512 bits, generated in EAP
known by AAA peer and
server
for generating Mobile IP
Root Key in CSN
CMAC_*KEY_*
128 bits, derived from AK,
SS MAC, BS ID
For Message Integrity
Check
WiMAX Key Hierarchy and Distribution
for ASN
for CSN
PKMv2 Procedures
Link activation triggers EAP
Routing based on NAI realm
PKMv2 three-way handshake
for mutual authentication
CMAC for MAC management
messages protection
KEK for encryption of TEK
Pairwise Key
Management
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
IP Configuration Setup
Point of Attachment (PoA)
address
has to be routable in the CSN and
ASN, and SHALL be assigned from
the CSN address space
For portable and mobile access, the
PoA SHALL be assigned from
either Home NSP or Visited NSP,
corresponding to the Home address
(HoA)
Fixed and nomadic access
scenarios
DHCP
Mobile access scenarios
PMIP4 / CMIP4 / PMIP6 / CMIP6
H-AAA
H-AAA
HA
HA
IP Configuration Setup Procedure
(Proxy Mobile IP)
Proxy Mobile IP
IP Configuration Setup Procedure
(Client Mobile IPv4, CMIPv4 )
Foreign
Agent (FA)
Home Agent
(HA)
Corresponded
Node ()
Mobile Node
(MN)
Binding Update
Data Transmission
Home
Network
Foreign
Network
Mobile IPv4 (MIP)
IP Configuration Setup Procedure
(Client Mobile IPv6 ,CMIP6 )
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
Mobility Management
MAC layer handover procedures
Handoff process
Three levels of association
Two optional modes of HO decision
and initiation
Intra-ASN mobility
ASN Anchored Mobility
inter-ASN mobility
ASN Anchored Mobility (Profile A &
C)
CSN Anchored Mobility
Mobility scenario
Stages of Handoff
Process
Cell reselection
MS may use Neighbor BS information in MOB_NBR-ADV
or scan Neighbor BS for handing over to potential target
BS.
HO Decision and Initiation
A handover begins with a decision for an MS to handover
from a serving BS to a target BS. The decision may
originate either at the MS, the serving BS, or on the
network.
Termination with the Serving BS
After the handover request/response handshake has
pleted, the MS may begin the actual HO. During the HO
process, the MS terminates service with the serving BS by
sending a MOB_HO-IND message.
Network entry/re-entry
Three levels of
association
Association
an optional initial ranging procedure in scanning interval
enables the MS to acquire service information for proper
selection of HO target and/or expediting a potential future
handover to a target BS.
Level 0: Scan / Association without coordination
The Serving BS allocates periodic intervals where the MS may
range neighboring BSs; the Target BS provides only contention-
based ranging allocations.
Level 1: Association with coordination
The Serving BS coordinates association between the MS and
neighboring BSs, with unique code and transmission opportunity
to prevent collision.
Level 2: Network assisted association reporting
The MS is required only to transmit the CDMA ranging code at
the neighbor BS. The Serving BS may aggregate all ranging
related information (. PHY offsets and CIDs from BSs) into a
single MOB_ASC_REPORT message.
Two optional modes of
HO decision and
initiation
Diversity Set
A list of BSs that are involved in handoff process with MS
Macro Diversity Handover (MDHO)
MS may transmit to and receive from BSs in Diversity Set
at the same time
Fast BS Switching (FBSS)
An Anchor BS is defined among the BSs in Diversity Set
MS only municates with the Anchor BS for UL and DL
messages including management and traffic connections.
Transition from one Anchor BS to another (“switching”) in
Diversity Set is performed without invocating HO procedure
Two Mobility Levels in
WiMAX
ASN anchored mobility or micro mobility
The MS moves between Data Path Functions while
maintaining the same anchor FA sitting at the northbound
edge of the ASN network
The data flow between CSN and Data Path Functions pivots at
the anchor FA.
CSN is unaware of any mobility that occurs between ASN
Data Plane Functions
CSN Anchored Mobility Management or macro mobility
The MS changes to a new anchor FA
The new FA and CSN exchange signaling messages to
establish data forwarding path
ASN Anchored Mobility
Management(1/3)
ASN Anchored Mobility
Management is defined as
mobility of an MS not involving a
CoA update (MIP re-registration)
ASN anchor Mobility
(2/3)
ASN anchored mobility (3/3)
CSN Anchored
mobility
For CSN Anchored Mobility Management two
variants of the MIP protocols are supported:
Client MIP (CMIP)
CMIP is an IETF pliant MIP solution based on a Mobile
IP enabled MS.
CSN Anchored Mobility Management will cover CMIP
based mobility schemes for IPv4 and IPv6.
Proxy MIP (PMIP)
Proxy MIP is an embodiment of the standard Mobile IP
framework in which an MN is transparently instanced in
the access network on behalf of a client that is not MIP-
aware or MIP-capable.
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.
CSN to ASN Anchored Mobility
Management Relationship (1/2)
CSN to ASN Anchored Mobility
Management Relationship (2/2)
Outline
WiMAX Introduction
WiMAX QoS & Flow
Network Working Group (NWG)
Network Reference Model
Network Entry
Authentication, Authorization, and Key Hierarchy
IP Configuration Setup
Mobility Management
QoS Functional Model
QoS Functional Elements
Service Flow Management
(SFM)
responsible for the creation,
admission, activation,
modification and deletion of
service flows.
Service Flow Authorization
(SFA)
Evaluate any service
request against user QoS
profile.
AF: Application Function
., 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
Pre-provisioned
service flow
