LTE系统随机接入过载控制的研究

Research on random access in LTE system based on RACH overload control

在同一个小区内,由于随机接入资源的有限性,当大量终端同时接入基站时,会造成网络拥塞,这会导致终端接入碰撞的概率增大,使随机接入成功率降低,同时导致随机接入传输时延增大这种情况,提出一种在网络拥堵环境下进行随机接入过载控制的方法。该方法通过对系统负载进行提前估算,根据网络负载情况动态调整随机接入的用户数和随机接入的时频资源,通过仿真得出该方法有效改善系统性能,使得用户接入时延较原有流程减少约35%,同时使用户接入成功率提升约45%。

Due to the liniteness lor random access resource in one cell,when many terminals want toaccess to the base station, it leads to network congestion which causes to increase the probability olcollision,reduces the access probability ol success and increase the delay ol access. Aimed at thesituation,the paper proposes an overload control method under the environment ol network congestionwhich can estimate the system load in advance to adjust the number ol terminals which want to access tothe base station and the time-frequency resources ol random access,it can effectively improve the systemperformance,it can make random access average delay reduce 35 percent compared with the originalprocedure and raise the random access success rate 45 percent.