基于PMP模式的IEEE802.16系统中Ranging问题

Ranging problem in IEEE 802.16 system based on PMP mode

研究了IEEE802.16在PM P(点到多点)模式下的Rang ing过程中竞争冲突问题.运用生灭过程分析了在确定SS数目的情况下需要Rang ing的SS数量模型,并计算出了需要Rang ing的SS数量的稳态解.根据随机过程理论提出了SS在Rang ing过程中单步竞争转移模型,在此基础上以单位Rang ing带宽下SS的Rang ing竞争成功率最大为原则推导出了最优的Rang ing带宽.最后,分别在非最优带宽、Sungm in给出的带宽和最优带宽下对Rang ing过程进行仿真,结果表明,最优Rang ing带宽下比其他2种带宽下的Rang ing成功率提高20%,而Rang ing的竞争次数和总的Rang ing时延分别降低25%和20%.

The contention collision of ranging process in the IEEE 802. 16 based on the PMP （point- to-multipoint） mode is researched. The amount model of SS （subscriber station）, which needs ranging, is analyzed by using birth-death process under the condition of the given number of SS, and then the steady state solution of the amount is computed. The one-step transition model of ranging contention is proposed according to the stochastic process theory, the optimum ranging bandwidth is deduced on principle that the contention success ratio of Ranging is maximal under the circumstances of the unit ranging bandwidth. Finally, the simulation of ranging process is individually done under the non-optimum bandwidth, the bandwidth given by Sungmin and the optimum bandwidth. The results indicate that the ranging success ratio of optimum bandwidth increases 20%, while ranging times and total delay decrease 25% and 20% comoared to the other two bandwidths.