Inter-cell Interference Exploitation through Distributed Symbol Level Precoding for Multi-cell MISO Systems

In this paper, we propose distributed symbol-level precoding (SLP) schemes to manage inter-cell interference in downlink multi-user multi-cell coordination systems. Initially, we introduce the constructiveness as a novel metric to quantify the received signal quality. We then define the square of the constructiveness-over-noise ratio (CoNR) to represent the equivalent signal-to-noise ratio (SNR). Subsequently, we propose a distributed precoding scheme where each base station (BS) aims to maximize the CoNR obtained by the worst user within its cell while ensuring inter-cell interference remains constructive. To further manage interference, we propose an additional distributed precoding scheme, where each BS enhances overall system performance by maximizing the sum of the minimum constructiveness from both intra-cell and inter-cell interference. Simulation results demonstrate that our proposed distributed precoding schemes surpass traditional block-level precoding in performance.