Advanced Communication Network Joint Throughput Optimization for Wireless Mesh Networks R 戴智斌 R 蔡永斌 Xiang-Yang Li, Senior Member, IEEE, Ashraf Nusairat, Student Member, IEEE, Yanwei Wu, Student Member, IEEE, Yong Qi, Member, IEEE, JiZhong Zhao, Member, IEEE, Xiaowen Chu, Member, IEEE, and Yunhao Liu, Senior Member, IEEE IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 8, 2009

Advanced Communication Network Outline  Introduction  System Model and Assumption  Problem Formulation  Efficient TDMA Scheduling  Performance Evaluation  Conclusion

Advanced Communication Network Introduction

Advanced Communication Network Introduction (1/2)  Wireless mesh network (WMNs) are being used for extending the Internet connectivity for mobile nodes.  Many US cities (e.g. Medford, Oregon, Chaska, Minnesota; Nashville, Illinois; and Gilbert, Arizona) have deployed WMNs.

Advanced Communication Network Introduction (2/2)  The major problem of WMNs is the reduction of capacity due to interference caused by simultaneous transmissions.  How to optimize joint throughput under certain fairness constraints via joint routing, link scheduling, and dynamic channel assignment.

Advanced Communication Network System Model and Assumption

Advanced Communication Network System Model and Assumption 7  Wireless Mesh Network – MMM for (multihop multiradio multichannel) – with multiple sink nodes (wireless router with gateway function) Internet

Advanced Communication Network Assumptions  Different nodes may have… – Multiple radios – Multiple channels – Different transmission range and interference range – Combined channel 8

Advanced Communication Network Dynamic Channel Combining Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Combining Interference Node 1Node 2

Advanced Communication Network System Model and Assumption  Multiple radios – Virtual nodes and links 10 u z v w

Advanced Communication Network System Model and Assumption  Why we need interference models? – PrIM, fPrIM, RTS/CTS, TxIM 11 Sender 1 Receiver 1 Sender 2 Receiver 2 Interference

Advanced Communication Network Problem Formulation

Advanced Communication Network Problem Formulation  Given: – an MMM WMN G = (V,E), flow demand l (u) from each sourch node u.  Objective – Maximize Fairness – Maximize Joint Throughput 13

Advanced Communication Network Maximize Fairness 14 Node 1 Node 4 Node 3 Node 2 Node 6 Node 7 Node 5 Mobile Client The flow coming to the node The flow going out of the node Achieved Flow

Advanced Communication Network MAX Fairness LP 15

Advanced Communication Network Maximize Joint Throughput 16 Internet Node Gateway Router

Advanced Communication Network MAX Joint Throughput LP 17

Advanced Communication Network Interference Free Schedule  Link Scheduling – Give each link a schedule – list of time slots and corresponding channels  Objective – interference free 18

Advanced Communication Network Mixed IP MAX Flow Fairness 19

Advanced Communication Network LP Flow Fairness  Maximize Fairness 20

Advanced Communication Network  Maximize Joint Throughput 21

Advanced Communication Network Efficient TDMA Scheduling

Advanced Communication Network Efficient TDMA Scheduling  Centralized scheduling for link transmission – Assume that T is the number of time slots per scheduling period. – We need to schedule time slots for a virtual link using channel. 23

Advanced Communication Network Efficient TDMA Scheduling

Advanced Communication Network Links Sorting  Different links sorting algorithm – Our algorithm relies on some special sorting of the links, which depends on the interference models. – No common sorting that works for all interference models. 25

Advanced Communication Network Improvement  Parametric searching improve the overall achieved flow. 26

Advanced Communication Network Performance Evaluation

Advanced Communication Network Impact of Multichannels (1/1) When channel combining is performed, it provides higher throughput and higher fairness.. Increasing the number of channels per radio increases the throughput and fairness.

Advanced Communication Network Impact of Multiradios (1/1) When channel combining is performed, it provides higher throughput and higher fairness.. The bouncing is that the actual number of radios assigned to each node is randomly generated for each simulation run. Increasing the number of radios per node “seems to” increase the throughput and fairness.

Advanced Communication Network Impact of Interference Model (1/1) With channel combining, the network receives the highest fairness and throughput under PrIM, while it receives the lowest fairness under the RTS/CTS model and lowest throughput throughput under TxIM.

Advanced Communication Network Impact of Interference Model (1/1) Without channel combining, the network receives the highest fairness and throughput under PrIM, while it receives the lowest fairness and throughput under the RTS/CTS model.

Advanced Communication Network Conclusion

Advanced Communication Network Conclusion (1/1)  The main contributions of this paper are – Theoretical performance guarantee for algorithms. – Impact of channel combining. – Realistic models and other restrictions.

Advanced Communication Network