Exploiting Spectral Reuse in Resource Allocation, Scheduling,and Routing for IEEE

802.16 Mesh Networks

Lien-Wu Chen, Yu-Chee Tseng Department of Computer Science, National Chiao-Tung University

Da-Wei Wang, and Jan-Jan WuInstitute of Information Science, Academia Sinica

IEEE VTC 2007

Outline

Introduction Related work Resource Allocation and Scheduling

Schemes Routing Tree Construction Simulation Conclusion

Introduction

The IEEE 802.16d specifies a centralized scheduling scheme for mesh networks

The SSs notify the BS Data transfer requirements The quality of their links to their neighbors

The BS uses the topology information along with the requirements of each SS to decide the routing and the scheduling

Background_ maintain routing tree

BS broadcast MSH-CSCF (Mesh Centralized Scheduling Configuration) message to all SSs

Background_ uplink and downlink

(1) BS collects MSH-CSCH: request (Mesh Centralized Scheduling) message from all SSs (2) BS broadcasts MSH-CSCH:grant to all SSs

Request

grant

Title: Interference-Aware IEEE 802.16 WiMax Mesh

Networks

Authors: H.-Y. Wei, S. Ganguly, R. Izmailov, and Z. Haas.

From: IEEE VTC’05

Related Work

Related Work

the algorithm does not fully exploit spectral reuse and it is not load-aware

Related Work

Title: Spatial Reuse in IEEE 802.16 Based Wireless Mesh

Networks

Authors: L. Fu, Z. Cao, and P. Fan.

From: IEEE ISCIT’05

Related Work

Related Work

link 1,4,7 and link 2,5,8 are simultaneous, respectively

L8

SS8 SS7 SS6 SS5 SS4 SS3 SS2 SS1

L7 L6 L5 L4 L3 L2 L1

Related Work

new

the algorithm does not fully exploit spectral reuse and it is not load-aware

Although how to attach a new SS to a mesh tree is discussed, but scheduling is not addressed in that work

Related Work

Resource Allocation and Scheduling Schemes_ goal

First, dynamically adapt the bandwidths between uplink and downlink subchannels

Second, proportionally allocate frame timeslots among SSs

Finally, obtain higher gateway throughput based on the above two manners.

Resource Allocation and Scheduling Schemes_ System Model

Resource Allocation and Scheduling Schemes

is uplink rate of SSi

is uplink traffic demands of SSi

is the demand of transmission time of SSi

is the total uplink transmission time of the network

is the total uplink transmission time of extended neighborhood of SSi

Resource Allocation and Scheduling Schemes

time

SS1

SS1 addition

The maximal transmission time for SSi =

for non-real-time or best effort traffic

Resource Allocation and Scheduling Schemes

, the bottleneck SS will see 100% busy carriers

tim

e

Resource Allocation and Scheduling Schemes

Channel-Level Scheduling Link-Level Scheduling

downlink

time

uplink

Channel-Level Scheduling :

Resource Allocation and Scheduling Schemes_ link level scheduling

uC3

uC2

uC7

uC2

3

1 2

4

56

7uC6

uC1

uC4

uC5 +

Phase 1Phase 2

Resource Allocation and Scheduling Schemes

Routing Tree Construction

Routing Tree Construction

1

Routing Tree Construction

uC7

uC2

3

1 2

4

56

7

A={3,4,5,6,7}

B={ }

uC5

A={3,4,5,7}

B={6 }

Initial :

is the highest data rate among links of SS j to itsneighbors with less or equal hop count

is uplink traffic demands of SSi,

Simulation

System parameter : A single channel OFDM PHY A single BS ( node 0 ) 84 SSs ( node 1 ~ 84 ) Channel bandwidth is set to 50

Mb/s Data rate of all links are the sa

me The extended neighborhood of

each SS includes one-hop and two-hop neighbors

Simulation_ Physical Layer Parameter

Simulation_ Burst Profile

Conclusion

An integrated spectral reuse framework for centralized scheduling scheme and routing tree construction is developed

This method is most complete in exploiting spectral reuse

Thank You~