• New NS-2 model developed for the IEEE 802.16
specifications is now publicly available.
This model was developed as part of the Seamless
and Secure Mobility Project in the Advanced
Network Technologies Division at NIST.
information and documentation is available on the project web pages:
http://www.antd.nist.gov/seamlessandsecure/toolsuite.html
To obtain a copy of this module, please send an email request to:
[email protected]
NS-2 Model for IEEE 802.16
• NS-2 model developed for the IEEE 802.16 specifications as part
of the Seamless and Secure Mobility Project in the Advanced
Network Technologies Division at NIST.
• Information and documentation is available on the project web
pages:
http://www.antd.nist.gov/seamlessandsecure/toolsuite.html
• To obtain a copy of this module, send an email request to
[email protected]
Model Overview: Physical layer
• Orthogonal Frequency Division Multiplexing
• Configurable parameters include:
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–
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Transmission power
Cyclic Prefix
Frequency
Frequency bandwidth
Modulation (BPSK, QPSK, 16QAM, and 64QAM)
• Support and functionality:
– Sampling frequency
– OFDM symbol time duration
– Transmission time for a packet according to its size and the
modulation used
– Maximum packet size for a given modulation and number of
available OFDM symbols
Model Overview: MAC layer
• Time Division Duplexing (TDD)
• Management messages for network entry:
– DCD/UCD, DL_MAP/UL_MAP
– Ranging request/response
– Registration request/response
• Flow management
– One downlink and one uplink data connection per SS.
• Extensible scheduler
– Round Robin
• Packet Fragmentation and Reassembly
• Mobility Extension (802.16e):
– Neighbor advertisement
– Scanning and handover
• IEEE 802.21 ready (trigger configuration and generation)
MAC Layer Parameter configuration
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•
•
•
•
•
•
•
Frame duration
DCD/UCD interval
Burst modulation
Channel
Contention size
Scanning attributes (number of iterations, duration)
Frequency of neighbor advertisements
Statistics (used for trigger generation)
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Loss
Delay
Jitter
throughput
Future work and missing features
• Future improvements:
– WirelessMAN-OFDMA physical layer
– ARQ (Automatic Repeat Request)
– Service Flow and QoS scheduling
– Periodic ranging and power adjustments
• Other missing features:
– ATM convergence sublayer
– Mesh networks
– WirelessMAN-SC, WirelessMAN-SCa,
WirelessHUMAN physical layers
– Frequency Division duplexing (FDD)
– Authentication
Implementation overview
Outgoing packet
Upper layer protocols
Classifiers
DSx frames
Synchronization
Messages
Service Flow Handler
Outgoing queues with
fragmentation per CID
Controls
frame
transmission
Scheduler
STA: process synchronization
messages from BS. Schedule
uplink traffic.
BS: generate synchronization
messages and schedule downlink
traffic. Also perform admission
control.
DSx frames
Synchronization
Messages
Service flows
Frame reassembly
OFDM Physical layer Incoming packet
Base/Mobile Station State Machine
Base Station
Mobile Station
Network entry
MN
BS
Channel Scanning
Downlink
synchronization
DL_MAP (Downlink map)
Link Detected
DCD (Downlink Channel Descriptor)
UCD (Uplink Channel Descriptor)
Uplink
synchronization
UL_MAP (Uplink map)
Ranging request
Initial ranging
Ranging response
Registration request
Registration
Registration response
Link UP
Establish uplink and downlink data connections
Normal operations (data Tx/Rx and maintain synchronization)
Handover in 802.16e (Link Down)
MN
Serving BS
Target BS
Normal operations
Link down detection
Link Down
Channel scanning
DL_MAP
Link Detected
Synchronization messages (DCD, UCD, UL_MAP)
Ranging
Registration
Link UP
Layer 3 handover
Normal operations
Handover in 802.16e (Link Going Down)
MN
Serving BS
Normal operations
Link Going Down
MOB-SCN_REQ
MOB-SCN_RSP
Channel scanning
Repeat
scanning
and normal
mode
intervals
Scanning
Synchronization messages (DL_MAP,DCD, UCD, UL_MAP)
Normal mode
MOB-SCN_REP
MOB-MSHO_REQ
Link Handoff Imminent
MOB-MSHO_RSP
MOB-MSHO_IND
Link Handoff Proceeding
Switch channel
Synchronization messages (DL_MAP,DCD, UCD, UL_MAP)
Full or Partial network entry
Ranging and Registration
Link Handoff Complete
Layer 3 handover
Normal operations
Target BS