NeTS: Small: Efficient CSMA in Wireless Networks: Theory, Protocol Design, and Implementation

近年来，无线局域网（WLAN）的部署经历了急剧的增长。已经开发了多个WLAN标准，包括IEEE 802.11的若干版本。IEEE 802.11的广泛部署是基于该标准的分布式协调功能（DCF）组件，该组件使用载波侦听多路访问（CSMA）来合并信道争用解决方案。然而，过去部署的基于CSMA的协议的一个重要缺点是它们无法实现最佳性能。 近年来，研究人员开发了新的吞吐量最优的CSMA算法。这些结果开辟了设计基于CSMA的协议，可以执行接近最佳的可能性。然而，吞吐量最优的CSMA的现有工作做了几个简化的假设，包括假设完美的载波侦听，链路之间的对称干扰关系，和固定速率传输。这个项目的主旨是开发基于CSMA的调度机制，可以很好地工作在实际的网络。为了实现这一目标，该项目研究了不切实际的假设和约束的系统放松，并试图开发在放松条件下表现良好的CSMA算法。该项目的范围包括在实验测试平台上执行选定的协议。该项目将在无线多跳网状网络以及基于基础设施的无线局域网的背景下探索CSMA。该项目的预期成果包括新的理论算法以及在实践中可以表现良好的基于CSMA的高效协议。

Deployment of wireless local area networks (WLAN) has undergone dramatic growth in recent years. Multiple WLAN standards have been developed, including several versions of IEEE 802.11. The widespread deployment of IEEE 802.11 is based on the Distributed Coordination Function (DCF) component of the standard, which incorporates channel contention resolution using CSMA (Carrier Sense Multiple Access). However, an important shortcoming of past deployments of CSMA-based protocols has been their inability to achieve optimal performance. In recent years, researchers have developed new throughput-optimal CSMA algorithms. These results have opened up the possibility of designing CSMA-based protocols that can perform close to the optimal. However, the prior work on throughput-optimal CSMA makes several simplifying assumptions, including assumptions of perfect carrier sensing, symmetric interference relationship between links, and fixed rate transmissions. The thrust of this project is on developing CSMA-based scheduling mechanisms that can work well in practical networks. Towards this goal, the project investigates systematic relaxation of unrealistic assumptions and constraints, and attempts to develop CSMA algorithms that can perform well under the relaxed conditions. The scope of the project includes implementation of selected protocols on an experimental testbed. The project explores CSMA in the context of wireless multi-hop mesh networks, as well as infrastructure-based wireless LANs. Expected results from the project include new theoretical algorithms as well as efficient CSMA-based protocols that can perform well in practice.