23-11-2012, 01:14 PM
WiMAX: Broadband Wireless Access
[attachment=40801]
802.16 Standards Development
Use wireless links with microwave or millimeter wave radios
10-66 GHz
802.16a extension to 2-11 GHz
Use licensed spectrum (unlicensed too in 802.16a)
Metropolitan in scale
Provide public network service to fee-paying customers
Point-to-multipoint architecture with rooftop or tower-mounted antennas
Provide efficient transport of heterogeneous traffic supporting QoS
Capable of broadband transmissions (2-75 Mbps)
Accommodate both continuous and bursty traffic
Mobile extensions: 802.16e
Protocol Architecture
Physical layer functions:
Encoding/decoding of signals
Preamble generation/removal
Bit transmission/reception
Medium access control layer functions:
On transmission, assemble data into a frame with address and error detection fields
On reception, disassemble frame, and perform address recognition and error detection
Govern access to the wireless transmission medium
Burst Profiles
Each subscriber station negotiates a burst profile with the base station
Burst profiles decided based on QoS needs and channel conditions
Harsher environment demands more robust profiles
Favorable environment allows efficient profiles
IEEE 802.16.1 Frame Format
Header - protocol control information
Downlink header – used by the base station
Uplink header – used by the subscriber to convey bandwidth management needs to base station
Bandwidth request header – used by subscriber to request additional bandwidth
Payload – either higher-level data or a MAC control message
CRC – error-detecting code
Medium Access Control (MAC)
Connection-oriented
All services inherently connectionless mapped to a connection
Connections referenced using a 16-bit connection identifier (CID)
Management channels and transport channels for contracted services
Radio Link Control
Power control and paging
Transition among burst profiles
Downlink burst profile change
Subscriber station monitors downlink quality
Requests a new profile
Granted if base station judges possible
Uplink profile change
Base station monitors the uplink signal quality
Specifies the new profile’s usage code when granting subscriber bandwidth in a frame
MAC Management Messages
Dynamic service change request, response, and acknowledge
Dynamic service deletion request and response
Multicast polling assignment request and response
Downlink data grant type request
ARQ acknowledgment
[attachment=40801]
802.16 Standards Development
Use wireless links with microwave or millimeter wave radios
10-66 GHz
802.16a extension to 2-11 GHz
Use licensed spectrum (unlicensed too in 802.16a)
Metropolitan in scale
Provide public network service to fee-paying customers
Point-to-multipoint architecture with rooftop or tower-mounted antennas
Provide efficient transport of heterogeneous traffic supporting QoS
Capable of broadband transmissions (2-75 Mbps)
Accommodate both continuous and bursty traffic
Mobile extensions: 802.16e
Protocol Architecture
Physical layer functions:
Encoding/decoding of signals
Preamble generation/removal
Bit transmission/reception
Medium access control layer functions:
On transmission, assemble data into a frame with address and error detection fields
On reception, disassemble frame, and perform address recognition and error detection
Govern access to the wireless transmission medium
Burst Profiles
Each subscriber station negotiates a burst profile with the base station
Burst profiles decided based on QoS needs and channel conditions
Harsher environment demands more robust profiles
Favorable environment allows efficient profiles
IEEE 802.16.1 Frame Format
Header - protocol control information
Downlink header – used by the base station
Uplink header – used by the subscriber to convey bandwidth management needs to base station
Bandwidth request header – used by subscriber to request additional bandwidth
Payload – either higher-level data or a MAC control message
CRC – error-detecting code
Medium Access Control (MAC)
Connection-oriented
All services inherently connectionless mapped to a connection
Connections referenced using a 16-bit connection identifier (CID)
Management channels and transport channels for contracted services
Radio Link Control
Power control and paging
Transition among burst profiles
Downlink burst profile change
Subscriber station monitors downlink quality
Requests a new profile
Granted if base station judges possible
Uplink profile change
Base station monitors the uplink signal quality
Specifies the new profile’s usage code when granting subscriber bandwidth in a frame
MAC Management Messages
Dynamic service change request, response, and acknowledge
Dynamic service deletion request and response
Multicast polling assignment request and response
Downlink data grant type request
ARQ acknowledgment