Achieving downlink macro-diversity in cellular networks by exploiting interference alignment

This paper studies the multi-cell cooperative transmission based on interference alignment (IA). A new macro-diversity approach is presented in which each BS not only transmits data to its serving users but also transmits data to the users belonging to the cooperative BSs. By coherently designing the precoding and detection matrices, desired signals from multi-BSs are detected to achieve macro-diversity while undesired signals are aligned to the same dimension before zero-forced by the detector. Additionally, an iterative algorithm based on the well-known leakage interference minimization approach is presented for the implementation of interference alignment in macro-diversity scenario. Simulation results show the proposed scheme has better outage probability performance at the high signal-to-noise ratio (SNR) region compared with conventional interference alignment, confirming the macro-diversity is achieved.