Dynamic Bandwidth Quasi-reservation Scheme for Real-time Services in IEEE 802.16e Networks

Yin Ge,and Geng-Sheng Kuo

IEEE Wireless Communications and Networking Conference, 2007.WCNC 2007

Outline

Introduction Related Content in IEEE 802.16e

Standard The Dynamic Bandwidth Quasi-

Reservation Performance Simulation Conclusion

Introduction

IEEE 802.16e standard did not specify any bandwidth reservation scheme that provides quality of service (QoS) support for real-time services Handover

real-time services > non-real-time

IEEE 802.16e Standard Two-phase activation model

Consideration for Handover cannot be guaranteed to get the required

bandwidth

Dynamic bandwidth quasi-reservation scheme (DBQRS)

based on the handover probability the traffic arrival probability

Provide QoS guarantee for real-time multimedia services

The Proposed DBQRS

The probability of MS requiring BS to reserve bandwidth

Type 0 traffic Type 1 traffic

MS 1MS 2

MS …

SF 3

SF 0 SF 1

SF 2 SF 3

SF 0

SF 2

SF 1

The probability of MS requiring BS to reserve bandwidth

handover and traffic arrival are independent

The probability of MS requiring BS to reserve bandwidth

Due to the different handover states as well as the diverse QoS requirements of traffics Weighting coefficients αn

UGS ERT-VR RT-VR

Handover states Weighting coefficients βk

βin : immigrate into the BS’s coverage area from the neighbor cells

βstay : stay in the BS’s coverage area βout : move out of the serving BS’s coverage

area

dynamic bandwidth quasi-reservation for MSs according

Admission Control Policy

Implemented a handover MS with active SFs enters the BS’s coverage, and a local MS issues new SFs

Real-time SFs arrive, non-real-time SFs must release the reserved bandwidth By initiating DSC message to change the

state of non-real-time SFs to be inactive

Admission Control Policy (real-time SF)

Admission Control Policy (non-real-time SF)

EX

Bandwidth

MS

…

Quasi-Bandwidth reservation

Bfree

Performance Simulation simulation model: OPNET Modeler 7 hexagonal cells 70 local MSs 30 handover MSs per cell evaluation on the central cell weighting coefficients α1=1 for UGS, α2=0.8 for RT-VR/ERT-VR βin=1 for the incoming handover MSs, βstay=0.

5 for the local MSs and βout=0.2 for the outgoing handover MSs

Traffic models

New SF blocking rate & Access delay

Handover SF dropping rate & Bandwidth utilization

Conclusion The proposed scheme not only provides Qo

S guarantee for real-time services, but also ensures the fairness of admitting handover and new real-time services

The proposed scheme achieves low NSBR and HSDR, low access delay for new real-time service as well as high system bandwidth utilization

Thank you!