New NS-2 model developed for the IEEE 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: To obtain a copy of this module, please send an request to:

NS-2 Model for IEEE NS-2 model developed for the IEEE 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: To obtain a copy of this module, send an request to

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

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 ready (trigger configuration and generation)

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

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 OFDM Physical layer Upper layer protocols Classifiers Frame reassembly Outgoing queues with fragmentation per CID Service Flow Handler Service flows 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 Controls frame transmission Outgoing packet Incoming packet Synchronization Messages

Base/Mobile Station State Machine Base StationMobile Station

Network entry MNBS Channel Scanning Establish uplink and downlink data connections DL_MAP (Downlink map) Link Detected DCD (Downlink Channel Descriptor) Ranging request Link UP UCD (Uplink Channel Descriptor) UL_MAP (Uplink map) Downlink synchronization Uplink synchronization Ranging response Initial ranging Registration request Registration response Registration Normal operations (data Tx/Rx and maintain synchronization)

Handover in e (Link Down) MNServing BSTarget BS Normal operations Link Down Link down detection Normal operations Channel scanning DL_MAP Link Detected Synchronization messages (DCD, UCD, UL_MAP) Ranging Registration Link UP Layer 3 handover

Handover in e (Link Going Down) MNServing BSTarget BS Normal operations Link Going Down Normal operations Channel scanning Synchronization messages (DL_MAP,DCD, UCD, UL_MAP) Link Handoff Imminent MOB-SCN_REQ MOB-SCN_RSP Scanning Normal mode Repeat scanning and normal mode intervals MOB-SCN_REP MOB-MSHO_REQ MOB-MSHO_RSP Link Handoff Proceeding Synchronization messages (DL_MAP,DCD, UCD, UL_MAP) Switch channel Ranging and Registration Link Handoff Complete Full or Partial network entry MOB-MSHO_IND Layer 3 handover