摘要
In an ultra-dense cellular system, users at the celledge are susceptible to inter-cell interference (ICI) because of the overlap of the spectrum. To combat ICI, this paper investigates two iterative ICI cancellation approaches for LDPCcoded multiple-input multiple-output (MIMO) systems. One approach includes separate signal and interference detectors; the other one employs a joint detector for both the desired signal and interference. The joint-detector approach achieves a comparable error-rate performance with only half the computational complexity when compared to the separate-detector counterpart. An iterative ICI cancellation receiver using the joint detector is proposed and implemented. Its hardware efficiency is significantly enhanced by leveraging an efficient coordinate rotation digital computer (CORDIC)-based processing array, an adaptive input-range scaling scheme, and an area-efficient loglikelihood ratio (LLR) calculator. The iterative ICI cancellation receiver is flexible enough to support multiple modulations of up to 256-QAM. The maximum gross throughput is 1.24 Gb/s for a 4&null 256-QAM configuration in a 40-nm CMOS technology. The proposed iterative receiver outperforms the current state-of-theart works in both the throughput-to-area ratio (TAR) and the normalized energy metrics, despite the added ICI capability.