Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi...

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Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Na ndi School of Computer Engineering Nanyang Technological University Singapore IEE Proceedings-Communications, Vol. 152, No. 3, June 2005

Transcript of Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi...

Page 1: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Full auto rate MAC protocol for wireless ad hoc networks

Z. Li, A. Das, A.K. Gupta and S. NandiSchool of Computer Engineering

Nanyang Technological University Singapore

IEE Proceedings-Communications, Vol. 152, No. 3, June 2005

Page 2: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Outlines

Introduction Motivation Modified Virtual Carrier Sensing (MVCS) Full Auto Rate (FAR) algorithm Analytical modeling Simulation Conclusion

Page 3: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Introduction

IEEE 802.11 standards provide high raw bandwidth and support multiple transmission rates

Several rate-adaptation algorithms had been proposed to improve the throughput Increase the utilization of bandwidthSuit the channel condition

Page 4: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Introduction (cont.)

However, these schemes considered the rate adaptation for the data frame only

The overhead of control frames which transmitted in the basic rate is considerable

Page 5: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Motivation

Page 6: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Motivation (cont.)

Page 7: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Motivation (cont.)

We could estimate the throughput by

Page 8: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Maximum throughput in IEEE 802.11b

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Bandwidth utilization

Page 10: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Objective

In this paper, the protocol aims to transmit the control frames at an acceptable higher rate

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MVCS

Page 12: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

MVCS (cont.)

When a MAC frame did not correctly be received with a correct FCS value, EIFS shall be used

Since EIFS = SIFS + DIFS + Tx(ACK) EIFS is long enough for transmitting any control frame

at any rate RTS and ACK should be always transmitted at the hig

hest rate under the given channel conditions

Page 13: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

MVCS (cont.)

If (Ldata / Rdata) < EIFSCTS should be transmitted at acceptable high

est rateThe higher data rate, the higher probability

Otherwise, CTS should be transmitted at the lowest basic rate

Page 14: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

FAR

RTS

CTS

S

R

Data

ACK

SIFS SIFS SIFS

RTS CTS DATA ACK

Cached Cached or basic-rate

Piggy backed in CTS

Piggy backed in Data

Data length L/Chosen rate ACK/Chosen rate 0

CTS*Basic-rate Duration value Duration value Duration value

Tx Rate

Duration Field

Defer Time

Page 15: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Analytical modeling

Throughput : RBAR+MVCS vs. RBAR

Page 16: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Improvements of MVCS

Page 17: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Analytical modeling (cont.)

Throughput : FAR vs. RBAR+MVCS

Page 18: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

FAR vs. RBAR+MVCS

Page 19: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Analytical modeling (cont.)

Throughput : FAR vs. RBAR

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FAR vs. RBAR

Page 21: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Simulation

NS-2 Transmission range/Carrier sensing range

250m Mobility

Random way-point mobility modelPause time = 0Maximum speed = 5m/s

Page 22: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Single flow within single-hop2 nodes

200 * 200

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Multiple flows within single-hop10 nodes200 * 200

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Multiple flows within multi-hop20 nodes

1000 * 500

Page 25: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Conclusion

This paper proposed a new rate adaptation algorithm: FARTransmit all the frames at the highest rate

under the given channel conditions To ensure the correct operation of VCS,

MVCS is proposed

Page 26: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Conclusion (cont.)

Both analytical and simulation show that the FAR algorithm greatly improves the performance of IEEE 802.11

Routing protocol should be considered in the future work

Page 27: Full auto rate MAC protocol for wireless ad hoc networks Z. Li, A. Das, A.K. Gupta and S. Nandi School of Computer Engineering Nanyang Technological University.

Thank you !