NR: Next Generation MAC Protocol for Multimedia Wireless Networks

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

The objective of this proposal will be to develop a new media access protocol that work efficiently in the wireless multihop environment, i.e., preserve battery power and bandwidth, provide QoS support and adhere to legacy standards, i.e., IEEE 802.11. The research is on a new MAC protocol, denoted by CSMA/CA2. The proposed scheme automatically adapts each node transmission rate to the bandwidth usage and the number of active nodes in the network. The proposed research includes a graceful rate adjustment algorithm that achieves fair channel access and a low collision rate, control theoretical analysis of the algorithm's parameters setting, and, provision of QoS support to diverse multimedia traffic. In addition, the proposed protocol adheres to the IEEE 802.11 CSMA/CA standard. The adherence to open standards broadens the scope of usage of the proposed algorithm, making it interoperable with other third party network interface cards that adhere to these open standards. The analysis and simulation studies demonstrate that the proposed CSMA/CA2 scheme has the following advantages of achieving significant power and bandwidth savings with reduced medium access delay compared to IEEE 802.11 CSMA/CA; it is easy to implement, i.e., CSMA/CA2 has low computational complexity and does not require additional control packets or buffers; it provides fair channel sharing with fast convergence; it is compatible with the IEEE 802.11 standard, i.e., nodes with both CSMA/CA and CSMA/CA2 can coexist in the same network; and, it can provide quality of service (QoS) support to different traffic classes. The project will extend the analysis to study the quantitative relationship between system convergence speed and the CSMA/CA2 parameters. In addition, it will define adjustments of the control parameters that allow the system to provide different QoS support to different senders. Thorough analysis, both theoretical and experimental, will be carried out to determine the trade-off between CSMA/CA2 performance under various coexistence environments as well as system convergence speed and stability. The project will also develop a wireless testbed that will allow us to test the proposed algorithms in a real wireless environment.