1. A Cooperative MAC Protocol for Wireless LAN Pei Liu, Zhifeng Tao, Shivendra S. Panwar Motivation: In the legacy 802.11 system, source station transmits to the receiver directly and transmissions received by other stations will be discarded. However, we can achieve better performance if user cooperation is allowed. Protocol illustration: –Neighboring nodes detection –Chosen of the helper –Channel reservation –Data frame and acknowledgement Protocol Validation: –Analytical model –Software simulation –Higher throughput and lower delay 1 RTS 3 CTS 2 HTS TsTs TdTd ThTh T2T2 1 RTS 3 CTS T1T1

2. Performance Evaluation of IEEE 802.11e Jeffrey (Zhifeng) Tao, Shivendra S. Panwar Protocol objective: Provide QoS support to upper layer applications (e.g., VoIPoWLAN, video streaming) Protocol illustration: * Reference: Z. Tao, S.S.Panwar, “An Analytical Model for the IEEE 802.11e Enhanced Distributed Coordination Function”, ICC 2004 Channel Busy Random backoff SIFS PIFS AIFS[ High Priority ] = DIFS Next Frame Defer Access Slot Time Randomly choose a backoff window size and decrement backoff counter as long as the medium stays idle Contention Window AIFS[ Low Priority ] Contention window from [1, 1+2 m CWMin[Priority Class]] High Priority Medium Priority Low Priority AIFS[ Medium Priority ] Analytical model: –Embedded Markov chain –Compute saturation throughput and service delay distribution –Capable of capturing all major QoS-specific features for the EDCF mode

3. Cooperation Medium Access Control Pei Liu, Jeffrey (Zhifeng) Tao, Shivendra S. Panwar Source Data Destination Helper Objective: Design new medium access control protocol to exploit the novel idea of “user cooperative”. Protocol features: –Backward compatible –Improve the throughput and delay performance of the legacy 802.11 network * Reference: P. Liu, Z. Tao, S.S.Panwar, “A Cooperative MAC Protocol for Wireless Local Area Networks,” submitted to ICC 2005

4. A P2P Video Streaming System with Multiple Description Coding Yanming Shen, Shivendra S. Panwar, Keith W. Ross, Yao Wang Motivation: Provide On-Demand video streaming service in a Peer-to-Peer network System architecture:: System design: –Multiple description video coding –Sub-stream placement –Admission control, server selection, sub-stream delivery Server & Client Client Server

5. A Mobile Ad Hoc Bio-Sensor Network Y. Li, S. Panwar, S. Burugupalli Achievements by Dr. John Chapin and his group at SUNY Downstate Medical Center. –Stimulate multiple brain regions of rats to produce stimulus cues for various commanded movements and rewards to reinforce their movements. –Use wireless communication to deliver brain stimulation. Remotely guided animals are ideal for search and rescue operations. –Natural disaster recovery –Homeland security –Military operations System architecture –Ad hoc network infrastructure –Control center –Mobile bio-sensor nodes: seeker, follower, relay Technical issues for wireless networking –Routing –Transport protocol –Backpack prototype development

6. Scheduling in High Speed Packet Switches Y. Li, Y. Shen, S. Panwar and H. J. Chao Fixed length Virtual Output Queueing (VOQ) switches Matching algorithms for scheduling in VOQ switches –Maximum Weighted Matching: stable, O(N3) –Maximal Matching: stable with speedup of 2 –Algorithms with memory: stable, with lower complexity, without speedup –Exhaustive Service Matching with Hamiltonian Walk (HE-iSLIP, HEDRRM) Stable under any admissible traffic Low implementation complexity, O(logN) Packet delay: much lower than other O(logN) algorithms, comparable to higher complexity algorithms. Load-balanced switch - No scheduler, 100% throughput - Packet delay: re-assembly delay + re-sequencing delay

7. Scheduling in High Speed Packet Switches Y. Li, S. Panwar and H. J. Chao Fixed length Virtual Output Queueing (VOQ) switches Matching algorithms for scheduling in VOQ switches –Maximum Weighted Matching: stable, O(N3) –Maximal Matching: stable with speedup of 2 –Algorithms with memory: stable, with lower complexity, without speedup Polling system based matching –Exhaustive Service Matching with Hamiltonian Walk (HE-iSLIP, HEDRRM) Stable under any admissible traffic Low implementation complexity, O(logN) Packet delay: much lower than other O(logN) algorithms, comparable to higher complexith algorithms. –Limited Service Matching (L-iSLIP, LDRRM)