Rayleigh信道下的多小区下行链路性能分析

Performance Analysis of Downlink Based Multi-Cellular  Systems in Rayleigh Fading

  • 摘要: 针对存在来自相邻蜂窝小区的同信道、不同功率信道干扰的单用户下行链路场景,分析了基站和用户均为单天线时的系统性能。系统模型为两个基站、两个用户,基站与用户均为单天线。在期望信号和干扰信号均为Rayleigh分布时,运用基于概率密度函数性能分析法推导了系统中断概率;基于瞬时信干噪比(SINR)的推导,并对瞬时误符号率(SER)取平均的方法推导了平均误符号率(ASER)的闭合表达式和用户的接收SINR的n阶矩;根据用户接收平均SINR的n阶矩表达式,推导并分析了用户接收平均SINR的衰落量(AF)性能。计算机仿真了在不同干扰功率下多小区系统的中断概率、ASER的性能以及AF性能。仿真结果表明:单小区和多小区系统的中断概率、ASER和AF的解析曲线均与数值仿真结果一致。系统性能随着干扰基站功率的降低而提升,系统性能随发送功率的增加增益明显。

     

    Abstract: In this paper, we analyzed the performance of the multicell downlink system in the presence of unequal power cochannel interference from the other cells. We adopt the system model composed with two cells and two users, which all equipped with one antenna, While the desired and interfering signals all in the presence of Rayleigh fading channel. First, the closed form expression of system outage probability is derived by using performance analysis method based on probability density function (PDF). Second, by deriving the instantaneous signal to noise plus interference ratio(SINR) and averaging the instantaneous symbol error ratio(SER), average symbol error ratio (ASER) and n order moments of user’s receiving SINR are evaluated. Last, an exact closed-form expression of the Averaging fading (AF) of averaging SINR is derived by using the expression of SINR. Computer simulated the outage probability, ASER and AF performance of the system with the different power of interference cell, while the system composed with two cells and two users. For the performance of outage probability, ASER and AF, Simulation results show that the analytical curves of the derived expressions match well with the numerical simulations. The case study under consideration and the corresponding derived expressions can usefully be employed to investigate the impact of various system and cochannel interference on the performance of multi-cell.

     

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