一种时效性约束的二进制指数退避算法

针对IEEE 802. 11标准中二进制指数退避算法(Binary Exponential 13ackoff,BEB)以最大重传次数作为分组丢弃依据其时效性性能差的问题，提出一种基于时效性约束的二进制指数退避算法(Delay-constrained Binary Expo-nential I3ackoff,D(', BEB)。以分组自身的超时门限替代最大重传次数作为分组丢弃的依据，能在不显著降低系统归一化吞吐量的同时，提高系统归一化有效吞吐量，适合于对分组时效性要求高的无线自组织网络。构建了Markov模型来分析采用!K; I3EI3算法时的系统性能。通过仿真实验，验证了模型的近似准确性以及IX; I3EI3算法相对于I3EI3算法的优势。

Delay-constrained Binary Exponential Backoff Algorithm

According to the problem of timeliness for IEEE 802. 11's binary exponential backoff algorithm,which usedmaxmum transmitting times, a new delay-constrained binary exponential backoff algorithm was proposed, which usedtimcout threshold instead of maxmum transmitting times as the reference for packet dropping. It can increase system u-nitary effective throughput,and doesn't reduce system unitary throughput dramatically,which is fit for wireless Ad hocnetworks demanding restrict delay. A Markov model was introduced to analyze system performance. The simulationsvalidate the accuracy of model and the advantagement of IBC BEB over BEB.