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.

1
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/toolsui
  te.html
• To obtain a copy of this module, please send an
  email request to
• sswm-dev_at_antd.nist.gov

2
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/seamle
  ssandsecure/toolsuite.html
• To obtain a copy of this module, send an email
  request to
• sswm-dev_at_antd.nist.gov

3
Model Overview Physical layer

• Orthogonal Frequency Division Multiplexing
• Configurable parameters include
• 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

4
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)

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MAC Layer Parameter configuration

• 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)
• Loss
• Delay
• Jitter
• throughput

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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

7
Implementation overview
8
Base/Mobile Station State Machine
Base Station
Mobile Station
9
Network entry
MN
BS
Channel Scanning
DL_MAP (Downlink map)
Downlink synchronization
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)
10
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
11
Handover in 802.16e (Link Going Down)
MN
Serving BS
Target 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
MOB-MSHO_RSP
Link Handoff Imminent
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