Cooperative transmission optimization for in-band wireless-backhauled small cell systems

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.