Centralized Resource Centralized Resource AllocationAllocation

for Multimedia Traffic infor Multimedia Traffic inIEEE 802.16 Mesh IEEE 802.16 Mesh

NetworksNetworksSpyros Xergias, Nikos Passas and Apostolis K. Salkintzis

Proceedings of the IEEE, 2008Proceedings of the IEEE, 2008

Mei-Jhen ChenMei-Jhen Chen

OutlineOutline

IntroductionIntroduction Extended Frame Registry Tree Extended Frame Registry Tree

SchedulerScheduler SimulationsSimulations ConclusionsConclusions

IntroductionIntroduction

IEEE 802.16 provides by supporting a wide range of traffic classes with different characteristics and quality of service (QoS) requirements.

The standard does not describe a specific traffic scheduler to utilize these parameters.

A scheduler for the centralized mesh mode of 802.16 referred to as the enhanced frame registry tree scheduler (E-FRTS).

Introduction Introduction -Goal-Goal

It prepares each time frame in advance and avoids complex processing during the short time period between two consecutive frames.

Extended Frame Registry Extended Frame Registry Tree Scheduler Tree Scheduler -overview-overview

The packet scheduler comes as an extension for mesh mode to the previously proposed frame registry tree scheduler [11].

[11] S. Xergias, N. Passas, and L. Merakos, “Flexible resource allocation in IEEE 802.16 WMAN”, in Proc. 14th IEEE Workshop Local Metropolitan Area Netw. (LANMAN 2005), Chania, Greece, Sep. 2005.

PMP mode

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler

-the Scheduler Goals-the Scheduler Goals The basic idea : to schedule the transmission of ea

ch piece of data in the last time frame before its deadline.

The main objectives of E-FRTS are the following : Modulation order from BPSK to 256-QAM A per QoS service treatment of the transmissions shoul

d be possible, based on a specific priority strategy. Data packet transmissions should be based on their dea

dline. Transmissions should be organized per SS and per conn

ection. For distant nodes, proper allocations to intermediate li

nks should be made.

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler -enhanced frame registry

tree

The operation of the scheduler can be divided into two main procedures : packet/request arrival Frame Creation

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler

-The Scheduler Operation-The Scheduler Operation

Assumed that a traffic policing mechanism is available at the MBS (e.g., leaky bucket) to ensure that the incoming traffic is consi

stent for UGS, ertPS, and rtPS servicesthe deadline of a packet Pi :Deadline(Pi) = ArrivalTime(Pi) + Latency(C(Pi)) –FrameDuration × h(C(Pi))

C(Pi) : the connection that packet Pi belongs toh(C(Pi)) : the number of hops to the destination of C(Pi)

for nrtPS and BE services

Extended Frame Registry Tree Extended Frame Registry Tree SchedulerScheduler

-The Scheduler Operation -The Scheduler Operation --Packet/Request Arrival

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler

-The Scheduler Operation -The Scheduler Operation --Packet/Request Arrival

64-QAM64-QAM

deadline

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler

-The Scheduler Operation --The Scheduler Operation -FFrame Creation Responsible for deciding on the contents structure of the next time frame of all neigh

borhoods

Enhanced Frame Registry Tree

NbHd. 01 NbHd. 02

TF1 TF2 TFm1 TF1 TF2 TFm2

… … …

… …

Extended Frame Registry Tree Extended Frame Registry Tree Scheduler Scheduler

-The Scheduler Operation --The Scheduler Operation -FFrame Creation Three cases can be distinguished for each ne

ighborhood’s TF1: the number of packets under subtree TF1 fits exa

ctly into one time frame the number of packets under subtree TF1 is less t

han the capacity of a time frame the number of packets under subtree TF1 is more

than the capacity of a time frame

SimulationsSimulations

a simulation program : C++ Two simulation scenarios:

Multiple Traffic Types ScenarioMultiple Traffic Types Scenario Multicast ScenarioMulticast Scenario

Simulations Simulations -Multiple Traffic -Multiple Traffic Types ScenarioTypes Scenario

-Assumptions-Assumptions

one UGS with constant data rate of 64 Kbps (e.g., voice) and latency equal to 20 ms

one rtPS with mean data rate of 256 Kbps and latency equal to 40 ms

one nrtPS with mean data rate of 128 Kbps one BE with mean data rate of 128 Kbps

Simulations Simulations -Multiple Traffic -Multiple Traffic Types ScenarioTypes Scenario

-Assumptions-Assumptions

time frame length :1 ms the packet size :54 bytes modulation : 64-QAM for all SSs a transmission speed : 120 Mbps Assume that only 50% of the bandwidth was

available for the above traffic.

Simulations Simulations -Multiple Traffic -Multiple Traffic Types ScenarioTypes Scenario

-Results-Results

Simulations Simulations -Multiple Traffic -Multiple Traffic Types ScenarioTypes Scenario

-Results-Results

Simulations Simulations -Multiple Traffic -Multiple Traffic Types ScenarioTypes Scenario

-Results-Results

Simulations Simulations -Multicast Scenario-Multicast Scenario-Assumptions-Assumptions

time frame length : 1 ms ideal channels the same modulation : 64-QA

M overall available bandwidth :

120 Mbps Each SS had two connections:

adaptive multirate (AMR) real-time video connection

Half of the SSs belonged to a multicast group that received high-bit-rate video.

Simulations Simulations -Multicast Scenario-Multicast Scenario-Results-Results

ConclusionsConclusions

Authors investigated how distributed multimedia can be supported in an IEEE 802.16 mesh network.

E-FRTS uses the frame registry tree, a data structure that aims at preparing time frame creation and reducing processing needs at the beginning of each frame.

Simulation results show that distributed multimedia traffic can be efficiently served in IEEE 802.16 mesh networks

Thank You !Thank You !