同频无线回传小基站系统中的协作传输优化

Cooperative transmission optimization for inband wireless-backhauled small cell systems

全双工的同频无线回传小基站可应用于阴影衰落严重区域的覆盖。在密集部署场景下,自干扰和小区间干扰严重影响系统传输性能。该文提出了一种基于集中式处理的同频无线回传小基站系统方案,采用空域和时域处理联合实现自干扰抑制和协作传输,并设计了一种基于连续凸近似和半正定松弛的迭代算法,对前向链路和回传链路上的波束成形/预编码及功率分配进行优化,从而降低系统发送功率。针对天线收发可切换的系统提出了一种复合算法,能够对收发天线进行高效选择。仿真结果表明:该方案能够有效抑制自干扰和小区间干扰,减小系统发送功率。

Full-duplex in-band wireless-backhauled small cells can provide coverage in areas suffering from deep shadow fading.Self interference and intercell interference severely degrade overall performance when such systems are very dense. A in-band wireless-backhauled small cell system design is given that features centralized processing. This design combines space-domain and time-domain techniques to mitigate self interference and improve cooperative transmissions. An efficient algorithm based on successive convex approximation and semi-definite relaxation is used to optimize the beamformer/precoder and the power allocation on the fronthaul and backhaul. A composite algorithm incorporating transmit/receive antenna selection is also given for systems with configurable antennas.Simulations show that this scheme efficiently suppresses self interference and intercell interference,resulting in lower transmission power.