Can One Achieve Multiuser Diversity in Uplink Multi-Cell Networks?

TL;DR

This paper proposes a distributed opportunistic scheduling strategy for uplink multi-cell networks, demonstrating that it achieves multiuser diversity and degrees-of-freedom gains with favorable throughput scaling, validated by simulations.

Contribution

It introduces a novel DOS scheme that attains optimal throughput scaling in multi-cell uplink networks under certain user scaling conditions.

Findings

Sum-rate scales as K log(SNR log N) at high SNR.

Achieves multiuser diversity and degrees-of-freedom gains.

Outperforms conventional schemes in simulations.

Abstract

We introduce a distributed opportunistic scheduling (DOS) strategy, based on two pre-determined thresholds, for uplink $K$-cell networks with time-invariant channel coefficients. Each base station (BS) opportunistically selects a mobile station (MS) who has a large signal strength of the desired channel link among a set of MSs generating a sufficiently small interference to other BSs. Then, performance on the achievable throughput scaling law is analyzed. As our main result, it is shown that the achievable sum-rate scales as $K\log(\text{SNR}\log N)$ in a high signal-to-noise ratio (SNR) regime, if the total number of users in a cell, $N$, scales faster than $\text{SNR}^{\frac{K-1}{1-\epsilon}}$ for a constant $\epsilon\in(0,1)$. This result indicates that the proposed scheme achieves the multiuser diversity gain as well as the degrees-of-freedom gain even under multi-cell environments. Simulation results show that the DOS provides a better sum-rate throughput over conventional schemes.