分层网络下行中断概率的闭式表达  

Closed Expressions of Downlink Outage Probability in Tiered Networks

作　　者：张文健[1] 田茂[1] 何浩[1] 沈祖康[2] 

机构地区：[1]武汉大学电子信息学院,武汉430079 [2]电信科学技术研究院,北京100191

出　　处：《西安交通大学学报》2011年第12期59-63,98,共6页Journal of Xi'an Jiaotong University

基　　金：国家科技重大专项基金资助项目(2009ZX03003-005);北京市自然科学基金资助项目(60202005)

摘　　要：针对用边界值形式表示的共信道干扰限制分层网络的下行中断概率不够精确的问题,采用随机几何理论建模网络结构,并在此基础上推导了每层下行中断概率的闭式表达式.首先构建了关于宏小区信号功率和毫微微小区聚合干扰功率的下行接收信干比函数,然后以聚合干扰功率为条件,根据宏小区信号功率的概率分布推导了接收信干比不高于门限值的概率,最后利用聚合干扰功率的概率分布计算条件中断概率的期望值,得到了中断概率闭式表达式.仿真结果表明:当毫微微小区基站发射功率降低3.16mW(小区平均数为100),或小区平均数减少20个(基站发射功率为100mW)时,能够分别使宏小区下行中断概率减小约20%或5%.Since the downlink outage probability expressed with bound value is not precise enough in co-channel interference-limited tiered networks,the stochastic geometry theory is used to model network framework and closed-expressions of per-tier downlink outage probability are derived based on the framework.The received signal to interference ratio（SIR） is formulated as a function of macrocell signal power and femtocell aggregated interference power.Then the probability for received SIR less than a threshold is derived according to the probability distribution of macrocell signal power in the condition on the aggregated interference power.The downlink outage probability is obtained by applying the probability distribution of aggregated interference power to calculate the expectation of conditioned outage probability.Simulation results show that the downlink outage probability in macrocell reduces about 20% and 5%,respectively,when the femtocell transmit power decreases 3.16 mW（the number of femtocells is 100 on average） or the number of femtocells decreases 20 on average（the femtocell transmit power is 100 mW）.

关 键 词：分层网络 毫微微小区 共信道干扰 中断概率 

分 类 号：TN929.5[电子电信—通信与信息系统]