Joint Scheduling and ARQ for MU-MIMO Downlink in the Presence of Inter-Cell Interference (original) (raw)
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Recent researches have greatly considered allocation of space resources in multiuser MIMO systems. The studies have proposed techniques to select the optimum group of users and their antennas greedily or fairly and transmit precoding methods to transmit multiple streams simultaneously to selected users with suppressed or minimum inter-user interference. According to our understanding, a new research trend in cellular multiuser MIMO systems is the consideration of other-cell interference in the scheduling and precoding methods. In fact, scheduling techniques have not been considered as much as precoding ones in such a system. So, in this article we propose some user and antenna selection methods in a system with other-cell interference. We also propose another modification to a modified BD precoding method for this system to lower the channel state information feedback rate.
Opportunistic scheduling using ARQ feedback in Multi-Cell Downlink
2010
Abstract We study cooperative, opportunistic multiuser scheduling using ARQ feedback in multi-cell downlink systems. Adopting the cell breathing ICI control mechanism, we formulate the scheduling problem as an infinite horizon discounted reward partially observable Markov decision process and study two scenarios. When the cooperation between the cells is asymmetric, we show that the optimal scheduling policy has a greedy flavor and is simple to implement.
2004
High-speed cellular data systems demand fast downlink scheduling algorithms and multiple-input multiple-output (MIMO) techniques. The associated multiuser diversity and antenna diversity play a central role in achieving high system throughput and fair resource allocation among multiple users. For such systems we evaluate the cross-layer interactions between channel-dependent scheduling schemes and MIMO techniques, such as space-time block coding (STBC) or Bell Laboratories Layered Space-Time (BLAST), and propose a new scheduling algorithm named the alpha-rule. The evaluation shows that the STBC/MIMO provides a reliable channel but at a certain cost of spectral efficiency. Comparatively BLAST/MIMO provides larger capacity and enables higher scheduling throughput. Thus BLAST/MIMO may be a more suitable technique for high-rate packet data transmission at the physical layer. At the medium access control (MAC)-layer, the alpha-rule is shown to be more flexible or efficient to exploit the diversity gains than the exiting max-C/I or proportionally fair (PF) scheduling schemes. It enables online tradeoff between aggregate throughput, per-user throughput, and per-user resource allocation.