This paper puts forth a new metric, dubbed channel cycle time, to measure the short-term fairness of communication networks. Channel cycle time characterizes the average duration between two successful transmissions of a user, during which all other users have successfully accessed the channel at least once. Compared with existing short-term fairness measures, channel cycle time provides a comprehensive picture of the transient behavior of communication networks, and is a single real value that is easy to compute. To demonstrate the effectiveness of our new approach, we analytically characterize the channel cycle time of slotted Aloha and CSMA/CA. It is shown that CSMA/CA is a short-term fairer protocol than slotted Aloha. Channel cycle time can serve as a promising design principle for future communication networks, placing greater emphasis on optimizing short-term behaviors like fairness, delay, and jitter.
翻译:本文提出了一种名为“信道循环时间”的新指标,用于衡量通信网络的短期公平性。信道循环时间表征用户两次成功传输之间的平均持续时间,在此期间所有其他用户至少成功接入信道一次。与现有的短期公平性度量相比,信道循环时间能够全面描述通信网络的瞬态行为,且是一个易于计算的单一实数值。为验证新方法的有效性,我们通过解析方式刻画了时隙ALOHA和CSMA/CA协议的信道循环时间。结果表明,CSMA/CA是一种比时隙ALOHA更公平的短期协议。信道循环时间可作为未来通信网络设计的基本原则,使网络更侧重于优化公平性、时延和抖动等短期行为。