Decentralized Linear Transceiver Design in Multicell MIMO Broadcast Channels

Abstract

This paper studies linear transceiver design in multicell MIMO Broadcast Channels (BCs). In this context, previous works have tried to enhance the conventional BD (cBD) algorithm, such as the proposal of iterative BD (iBD), which has less dimensionality restrictions and accounts for the inter-cell interference (ICI) presence. However, both approaches become interference-limited when the ICI has strong power. In this paper, we take a different direction by using the Weighted Sum-Rate (WSR) as the transceiver design creation. For that, three different novel algorithms are proposed in this paper, which are based on the alternating optimization technique and guaranteed to converge to a local WSR-optimum. The first algorithm is an interference pricing approach, where each cell maximizes its own utility, which is formed by the local users’ WSR minus the priced ICI leakage. The second algorithm designs the transceivers that maximize the network-wide WSR. Interestingly, we prove that the WSR maximization via interference pricing can be made equivalent to the network-wide WSR maximization, whenever the mobile stations are equipped with single-antennas. The third algorithm is an implicit interference pricing approach, where each cell self-prices its ICI leakage and, thus, does not require the feedback of variables from other cells. To facilitate the algorithms’ implementation, a novel Over-the-Air (OTA) signaling scheme based on the Time Division Duplex (TDD) mode is proposed, which reduces the signaling overhead and requires no backhaul feedback, as compared to existing schemes.