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Overview of NIST IEEE 802.16 implementation in NS-2. High Speed Network Technology Group. Physical layer. Implement Orthogonal Frequency Division Multiplexing Configurable parameters are: Transmission power Cyclic Prefix Frequency Frequency bandwidth
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Overview of NIST IEEE 802.16 implementation in NS-2 High Speed Network Technology Group Information Technology Laboratory, Advance Network Technologies Division
Physical layer • Implement Orthogonal Frequency Division Multiplexing • Configurable parameters are: • Transmission power • Cyclic Prefix • Frequency • Frequency bandwidth • Modulation (BPSK, QPSK, 16QAM, and 64QAM) • Computed values: • 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 Information Technology Laboratory, Advance Network Technologies Division
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: currently add one downlink and one uplink data connection per SS. • Extensible scheduler (currently Best Effort+Round Robin) • Fragmentation/Reassembly of packets • Mobility Extension (802.16e): • Neighbor advertisements • Scanning and handover • IEEE 802.21 ready (trigger configuration and generation) Information Technology Laboratory, Advance Network Technologies Division
MAC layer 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 Information Technology Laboratory, Advance Network Technologies Division
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 Information Technology Laboratory, Advance Network Technologies Division
Upper layer protocols Outgoing packet Classifiers Outgoing queues with fragmentation per CID DSx frames Service Flow Handler Synchronization Messages 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 Frame reassembly OFDM Physical layer Incoming packet Implementation overview Information Technology Laboratory, Advance Network Technologies Division
High level state machines Base Station Mobile Station Information Technology Laboratory, Advance Network Technologies Division
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) Information Technology Laboratory, Advance Network Technologies Division
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 Information Technology Laboratory, Advance Network Technologies Division
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 Information Technology Laboratory, Advance Network Technologies Division