• 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:sswm-dev@antd.nist.gov

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 sswm-dev@antd.nist.gov

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 802.21 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

DSx frames

Synchronization Messages

Controlsframe transmission

Outgoing packet

Incoming packet

Synchronization Messages

Base/Mobile Station State Machine

Base Station Mobile Station

Network entry

MN BSChannel Scanning

Establish uplink and downlink data connections

DL_MAP (Downlink map)

Link DetectedDCD (Downlink Channel Descriptor)

Ranging request

Link UP

UCD (Uplink Channel Descriptor)

UL_MAP (Uplink map)

Downlink synchronization

Uplink synchronization

Ranging responseInitial ranging

Registration request

Registration responseRegistration

Normal operations (data Tx/Rx and maintain synchronization)

Handover in 802.16e (Link Down)

MN Serving BS Target BS

Normal operations

Link Down

Link down detection

Normal operations

Channel scanning

DL_MAP

Link DetectedSynchronization messages (DCD, UCD, UL_MAP)

Ranging

RegistrationLink UP

Layer 3 handover

Handover in 802.16e (Link Going Down)

MN Serving BS Target BSNormal 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