基于干扰对齐的高铁无线宽带接入方案

Wireless broadband accessing scheme in high-speed railway based on interference alignment

依据高速铁路信号传输的特点,提出了基于干扰对齐的高铁无线宽带接入系统。该系统车载两套双天线设备,可以同时支持两个双天线用户无线接入,而接收端可以分离有用信号与干扰信号,实现无干扰接收。在车载设备与高铁沿线基站的通信中,提出基于传输时延的干扰对齐算法及与之相适应的网络覆盖方案。该算法按照时间传输奇偶顺序将来自不同发送端的信号分离。仿真结果表明,基于干扰对齐的车内接入子系统信号传输时可以达到四个和自由度,系统误码率优于未采用干扰对齐的系统,且下行误码率的性能略优于上行;基于传输时延的干扰对齐车地回传子系统可以同时支持两套车载设备接入网络且解码复杂度低,其覆盖方案可解决高铁越区切换易失败的问题。

According to the characteristics of high-speed railway, this paper proposed a wireless broadband access system based on interference alignment. This system contained two sets of dual-antenna train access units. It could support two dua- lantenna users access to the inside access system simultaneously. The receiver could separate expected signal from interference signal. It also proposed an improved interference alignment algorithm based on transmitting delay and its corresponding network coverage scheme. This algorithm could separate expected signal from interference signal according to different transmitting de- lay. Simulation results show that the inside access system can obtain totally four degrees of fi＇eedom and its performance of bit error rate is better than the system which does not adopt this interference aligmnent technology. Moreover, its performance of downlink bit error rate is slightly better than the uplink＇ s. In the backhaul system, two sets of train access units can access to the network simultaneously. Its decoding complexity is more lower and its coverage scheme can solve the problem of handoff failure.