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1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Overview WiMAX System Architecture
14th November 2006
Esa Viitanen
3 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Nokia WiMAX Program High-level Direction
• Lightweight, high-speed wireless, personal access to Internet with portability
• Main, initial use case:
• Laptop and
• Tablet Internet access,
• Walking between cells without loosing session (IP address) and/or VPN connection
• Substantially lower cost of ownership than 3G
• Hide system complexity from user and operator through automated operability, moving towards plug-and-play
• Usage of non-cellular licensed spectrum
4 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Terminals
• Operators start first with fixed and nomadic terminals• CPE boxes
• Ethernet and POTS interfaces• Indoor or outdoor antenna• Applications:
• Broadband Wireless - DSL replacement• Wireless Local Loop
• PCMCIA cards• For laptops
• WiMAX radio integrated in laptops• Intel WiMAX chipset coming to laptops in 2008
• And continue later with true mobile terminals• PDAs• Mobile handsets
• Starting from high-end business phones
• Cameras, … , with WiMAX radio
5 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX, Quick Overview on the Air Interface 802.16e• WiMAX is a TDD system
• With various carrier bandwidths: 3.5, 5, 10 MHz
• Frequency bands for WiMAX:• 2.5 GHz (licensed)• 3.5 GHz (licensed)• 5.8 GHz (unlicensed)
• Amount of spectrum needed:• Min. 10 MHz, typically 15 – 30 MHz
• Typical cell ranges @ 2.5 GHz:• 500 – 1500 m, for suburban and urban areas with indoor coverage• 5 – 10 km with outdoor antenna
• Estimated aggregate data rates per sector:• 4 Mbps per sector UL for a 10 MHz carrier• 13 Mbps per sector DL in case of 3x 10 MHz carrier used
• Network architecture:• IP based
6 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX, Standards
• IEEE 802.16d-2004• Fixed WiMAX air interface standard
• Nokia does not implement this
• IEEE 802.16e-2005• Mobile WiMAX air interface standard
• Nokia WiMAX is based on this, both for fixed and mobile WiMAX applications
• PHY and MAC layers
• WiMAX Forum recommendations• End-to-End Network Systems Architecture, reference model for
• ASN, Access Service Network and
• CSN, Core Service Network
• WiMAX Forum refers to a number of IETF RFCs
8 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Network Architecture
• There are two basic applications for WiMAX networks• Fixed/nomadic WiMAX
• Broadband Wireless access to Internet and Wireless Local Loop• In developing countries, rural areas, where copper cables do not exist• Providing DSL type access
• Mobile WiMAX• Mobile access to Internet• Complementary to current cellular networks - data overlay networks
• Nokia has two different WiMAX Network Reference Architectures• Fixed WiMAX Reference Architecture for DSL operators
• Provides Ethernet transport to the terminals - like DSL access• Mobile evolution adds local mobility (local handovers)
• Mobile WiMAX Reference Architecture for Mobile Operators• Adds wide area mobility• Provides IP transport to the terminals
9 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Fixed WiMAX Reference Architecture for DSL operators
BS
BS
BRAS ASP / NSP Network infra (AAA, DHCP, billing, subscriber db, …)
V
A10
DS
LA
MxDSL V
ETH
R1
.16e-2005
DS
LA
MxDSLCPE
TE
TE
. . .
CPE
TE
TE
. . .
T
CPE
TE
TE
. . .T
Laptop PCWiMAX i/f
OMSBS O&M
BTSOM
10 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Mobile WiMAX Evolution for DSL Operators
BS
BS
R1
R6 ASN GW
BRAS ASP / NSP Network infra (AAA, DHCP, billing, subscriber db, …)V
A10
ETH
R3aaa
xDSL VCPE
TE
TE
. . .
DS
LA
M
CPE
TE
TE
. . .
MSS
T
T
OMSBS O&MASN GW O&M
BTSOM
R1
Laptop PCWiMAX i/f CSN P&CF
AAA
11 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Fixed WiMAX – DSL Network, Physical Architecture
AAA
DHCP/DNS
DSL CPE
FWNAPT
Fiber core
Copper access
Microwave access
BS
O&MNetAct
GPS
LDAPSubs. DB
Internet
DSLAM
BRAS
MW IU
ADSL2+VDSL2
ASN CSN
OMS
12 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Mobile WiMAX Reference Architecture for Mobile Operators
MSS
BS
ASN GW
BSR1
R6
R2
ASN GW
CSNHA
CSN P&CFAAA
R3aaaRadius
R4
R3mipMIP
Network Management System(NetAct)
OMSNWI3
PostpaidCG
BS O&MASN GW O&M
X7
Internet
Subs. DBHLR/ HSS
FW/NAPT
LIGBS
DHCP/DNS
R1
CPE
TE
TE
. . .
. . .
T
X2
LIG
. . .
BTSOM
Laptop PCWiMAX i/f
R1
13 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Mobile WiMAX Network, Physical Architecture
HA
AAA
3xASN GW
OMSCore
DHCP/DNS
DSL NT
FWNAPT
Fiber core
Copper access
Microwave access
BS
AccessDHCP/DNS
LIG
NetAct (OSS)
GPS
Subs. DB
Internet
DSLAM BRAS
MW IU
ASN CSN
15 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Network Elements
• Nokia WiMAX Network Elements• BS Base Station• ASN GW Access Service Network GateWay• OMS Operation and Maintenance Server
• Commercial Network Elements• HA Mobile IP Home Agent• AAA Authentication, Authorization and Accounting Server
• Supplementary Elements• NetAct Network Management System• LIG Legal Intercept Gateway• IP transport elements Routers, Switches, DHCP/DNS, FW/NAPT• BS transport elementsMicrowave radios, xDSL NT, …
16 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Mobile WiMAX rel 1 – Flexi Base Station
• Based on the WCDMA Ariel BTS platform
• Outdoor, 19” 3U module
• Ethernet interface to network
• OBSAI RP3-01 optical interface to RF
• Separate RF head• 2TX/2RX, MRC, external antenna
• RF and BB MIMO capable
• TX power 36dBm, ~ 4 W
• Scalable bandwidth up to 10MHz
• 2.5GHz and 3.5GHz RF and antenna options
• PUSC (incl all SC)
• GPS based synchronization
RF Module
Antenna
OBSAI RP3-01 optical
17 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Frequency Allocation
f1f1
f1
sector #2 uses 1/3 of all
subcarriers
sector #3 uses 1/3 of all
subcarriers
sector #1 uses 1/3 of all
subcarriers
f1f2
f3
all sectorsuse all
subcarriers
f1
cell uses allsubcarriers
1+1+1
Single carrier
(Omni-directional)
PUSC,Partially Used SubCarriers
e.g. 10 MHz bandwidth
FUSC, Fully Used SubCarriers
e.g. 3 x 10 MHz bandwidth
18 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
ASN GateWay• Indoor network element
• 19” wide 1 U high
• Main functionalities• Mobility control (Handovers) between
Base stations
• Mobile IP Foreign Agent
• Authenticator
• Security key distribution
• Rate Limiting (Downlink)
• Paging
• Scalable element• Scalable by adding additional GWs
• Traffic routing and tunneling capacity• 2Gbits per box Downlink + 1Gbits Uplink
• Control plane capacity• 200 WiMAX Base station Cells
• Resiliency at network level
19 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
AAA - Authentication, Authorization, and Accounting Main functionalities:
• Authentication algorithms/methods
• Optionally allocates IP addresses for terminals at authentication phase
• Fetches the subscriber profiles from the subscriber and subscription databases
• Distributes QoS profiles to ASN GW
• Reports CDRs to the billing system
20 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
HA - Mobile IP Home Agent
Main functionalities:• Interfaces WiMAX User plane to the Internet, to other IP networks and to services• Optionally allocates IP HoA addresses for terminals• Performs handovers between ASN GWs• Needed only in large networks, for example for mobility between cities• Used also for roaming between other networks
21 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
OMS - Operation and Management Server
• Main functionalities:• WiMAX RAN mediator for NetAct
• Mediates BSs and ASN GWs
22 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Main WiMAX Interfaces
• R1• Encrypted WiMAX air interface • Between Base Station and Terminal
• R6• Interface between the BS and ASN GW• GRE tunneling in user plane and IPSec in control plane
• R3• User plane interface between ASN GW and Home Agent - Standard Mobile IP protocol • Control plane interface between ASN GW and AAA Server - Standard Radius protocol
• V interface• Interface between BS and BRAS (BRAS = Broadband Remote Access Server)• Ethernet based interface, according to TR-101, uses 1:1 and 1:N VLAN mappings• Needs case by case configuring, to interface with the operator’s existing DSL network
• AAA i/f• LDAP interface to operators Subscriber database, also a MAP interface to 2G/3G HLR/HSS• Typically FTP interface for collecting CDRs to operators postpaid billing system• AAA interfaces vary according to operator’s infrastructure and need an integration project
24 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX BS Site Transport
• Three sector 1+1+1 WiMAX BS average capacity is 8 … 24 Mbit/sec• Current GSM or WCDMA backhaul transport is too thin - not applicable for WiMAX
• Build a new transport to the WiMAX BS site
• WiMAX Transport solutions• Microwave radio links
• Ethernet leased lines (fiber or copper, possibly xDSL lines)
• A number of E1/T1 lines (initial solution only)
• WiMAX BS transport interfaces• Ethernet 100Base-TX
• Gigabit Ethernet 1000Base-SX/LX optical
• FlexBus with Ethernet transport, in Rel 2
• 8 x E1/T1, in Rel 2
25 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
BS Site Transport Options
BS
ASN GW
Router
Ethernet Switch
Ethernet (Leased)
Line
DSLAM
DSL NT
MWR-IU
BS Chaining
Ethernet
E1/T1
other
BS
E1/T1 (Leased)
Lines
27 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Authentication
• Mobile WiMAX uses EAP Authentication methods• Subscriber authentication, protocol run between the Terminal and AAA server
• Several EAP methods available• EAP-AKA for USIM
• EAP-TTLS for shared secret
• . . .
• WiMAX DSL interworking architecture uses the DSL Authentication methods available in BRAS
• DHCP Option 82 authentication, based on MAC address of the terminal
• PPP, user name / password authentication
28 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX User QoS
• Air interface QoS• Nokia Release 1 has three air interface QoS classes
• UGS - Unsolicited Grant Service, for continuous fixed bit-rate data streams
• ertPS - extended real time Polling Service, for VoIP traffic
• BE - Best Effort, for other traffic like browsing
• Implementation in BS scheduler
• Access Transport Network QoS• Two priorities in Nokia Release 1:
• “VoIP”
• “BE”
• Based on DiffServ
• User Data rate limiting • For traffic between the Terminal and ASN GW
• At subscriber service flow level
29 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
WiMAX Mobility
• Fixed / Nomadic Mobility• The usage is stationary• Moving without a connection
• Portable / Full Mobility• Handovers
• R6 mobility – tunnel switching between Base Stations (Inter BS handover)• R4 mobility – extending a tunnel through the next ASN GW (Inter ASN GW
handover)
• Network resource optimization• R3 mobility – Mobile IP (Inter ASN GW handover)• This is not exactly a handover, but network resource optimization after a number of
handovers• Small networks may not implement R3 handover, they may not have a Home Agent
• Idle mode and Paging• Implemented for saving the battery life in mobile devices• Paging is needed mainly for incoming VoIP calls (SIP calls)
30 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Mobility Cases: R6, R4 and R3 Mobility
ASN (NAP-A)
CSN (NSP-B)ASN Gateway (FA)
ASN Gateway (FA)
HA
R6
R4
1
2
3
0
R3
Network
Network