Download IEEE 802.16 Standard

IEEE 802.16 WirelessMAN
A Technical Overview of the
WirelessMAN Air Interface
for Broadband Wireless
Access
Carl Eklund
Roger B. Marks
Kenneth L. Stanwood
Stanley Wang
資訊工程學系碩士在職專班
學號 : 492515019
姓名 : 何俊慶
Agenda
• Why IEEE 802.16 wirelessMAN ?
• IEEE 802.16 Standard
– 802.16
– 802.16a
– 802.16b
• IEEE 802.16 theory
– Physical Layer
– MAC Layer
– BS SS initial
• Conclusion
• References
What are WMANs?
• WMAN: Wireless Metropolitan Area Network.
• They are meant to provide wireless access for large
residential areas.
• They are designed to provide Broadband Wireless
Access (BWA) services.
• BWA offers integrated high-speed links supporting
data, voice and video communication.
Applications
• It comprises a “Last Mile” solution. It is a suitable
cost-effective solution to replace copper and
fiber last mile connections.
– Buildings equipped with subscriber and base stations,
SS & BS
– Users connect to SS via conventional network
technologies (e.g. 802.3, 802.11)
– BSs connected directly to backbone
• Lowers barriers to entry for new ISPs increasing
competition
“Last Mile” solution
Wireless LAN Technology
WPAN
PAN
WLAN
WMAN
LAN
MAN
WWAN
WAN
IEEE-802.16
2.5G,GSM/TDMA/
CDMA
3G,GPRS/WCDMA
Personal Area
802.15/Bluetooth
Wireless LAN
802.11x/HiperLAN
Wireless MAN
IEEE-802.16
What technologies can we choose from?
• sample wireless applications (source: Cisco 2002)
PAN
LAN
MAN
WAN
BlueTooth
802.15
802.11
802.11b
802.11a
802.11g
802.16
(MMDS
LMDS)
CDMA,
G2.5-3,
GSM
speed
< 1Mb/s
1 to 54Mb/s
128Kb/s to
100Mb/s+
10 to 384Kb/s
range
Short
medium
medium-long
long
P2p
enterprise
last mile
mobile phones
standards
applications
Wireless Technologies
WMAN
Standards
General Overview
• Standard for wireless metropolitan area
networks (WirelessMAN™)
• Supports a variety of services such as IP,
voice over IP, and streaming video
• Protocol independent supporting ATM &
packet based protocols
Standardization of Wireless Networks
• Wireless networks are standardized by
IEEE.
• Under 802 LAN MAN standards committee.
Application
ISO
OSI
7-layer
model
Presentation
Session
Transport
Network
Logical Link Control
Data Link
Medium Access (MAC)
Physical
IEEE 802
standards
Physical (PHY)
IEEE 802.16 Standard
• P802.16 — Air interface for fixed BWA systems
at 10-66 GHz
–
–
–
–
–
Common MAC definition
Point-to-multipoint (PMP) operation
2 to 134 Mbps
Bandwidth on Demand system
Requires directional line-of-sight (LOS) propagation
IEEE 802.16 Standard
• P802.16a — 2-11 GHz licensed bands
– Point-to-multipoint BWA system
– 3 physical layer specs: Single Carrier, 256-point
OFDM, 2048-point multi-user OFDMA
– the standard tackles the Non-Line-of-Sight
applications
• P802.16b — License-Exempt Bands, with a
focus on 5-6 GHz
– Wireless High-Speed Unlicensed Metropolitan Area
Networks (WirelessHUMAN)
– Primary focus is 5-6 GHz (UNII band)
IEEE 802.16
Theory
802.16 protocol layer
802.16 Physical Layer
• Data rates
determined by exact
modulation and
encoding schemes
• TDMA and OFDMA
Channel Bit Rate
Size
(Mbps)
(MHz)
QPSK
Bit Rate Bit Rate
(Mbps) (Mbps)
16-QAM 64-QAM
20
32
64
96
25
40
80
120
28
44.8
89.6
134.4
Bit Rate Shifting in 802.16
Bit rate shifting is achieved using adaptive modulation. When you
are near to the BS, you are offered high speed, when you’re far,
reliability decreases, hence you’re offered lower speed.
802.16 MAC
• WirelessMAN operates at MAC sub-layer
of Data Link Layer
• MAC layer is further subdivided into three
layers
– Convergence sub-layer (CS)
– Common part sub-layer (CPS)
– Privacy sub-layer
IEEE 802.16 MAC layer function
• Transmission scheduling :
– Controls uplink and downlink transmissions so that
different QoS can be provided to each user
• Link initialization
– Scans for a channel, synchronizes the SS with the
BS, performs registration, and various security
issues.
• Support for integrated voice/data connections
– Provide various levels of bandwidth allocation
802.16 MAC: Privacy Sub-Layer
• Provides secure communication
– Data encrypted with cipher clock chaining
mode of DES
• Prevents theft of service
– SSs authenticated by BS using key
management protocol
802.16 MAC: CPS Layer
• Performs typical MAC functions such as
addressing
– Each SS assigned 48-bit MAC address
– Connection Identifiers used as primary address after
initialization
• MAC policy determined by direction of
transmission
– Uplink is TDMA
– Downlink is TDM
802.16 MAC: CS Layer
• Interoperability requires convergence sublayer to be service specific
– Separate CS layers for ATM & packet
protocols
• CS Layer:
– Receives data from higher layers
– Classifies data as ATM cell or packet
– Forwards frames to CPS layer
802.16 MAC Layer
FDD map relevance
802.16 MAC Layer
TDD map relevance
Physical Layer
Downlink subframe structure
Physical Layer
Upnlink subframe structure
BS SS initial
Transition to a more robust burst profile
BS SS initial
Transition to a less robust burst profile
802.16 MAC Layer
Generic MAC header format
802.16 MAC Layer
802.16 MAC Layer
Bandwidth Request header format
802.16 MAC Layer
Conclusion
WMAN Advantage
• 支援可變長度資料封包傳輸
•提供品質保證 QoS,包含頻寬需求與延遲控制、封
包分級、動態連結建立
•提供安全傳輸服務
•提供數種傳輸速度
•提供封包分割重整與TCP/IP相連時提供通透性連
接,可直接到任何網際網路
•建制容易,升級更新容易,成本低
References
REFERENCES
[1] IEEE 802.16-2001,”IEEE Standard for Local Metropolitan Area
Networks - Air Interface for Fixed Brodband Wireless Access
System.”Apr.8,2002
[2] IEEE P802.16a/D3-2001:”Draft Amendment to IEEE Standard for Local
and Metropolitan Area Networks – Air Interface for Fixed Wireless
Access Systems – Medium Access Control Modifications and Additional
Physical Layers Specifications for 2-11 GHz”Mar.25,2002
[3] IEEE 802.16.2-2001,”IEEE Recommended Practice for Local and
Metropolitan Area Networks – Coexistence of Fixed Broadband Wireless
Access Systems,”Sep.10,2001