A Tractable Model for Non-Coherent Joint-Transmission Base Station Cooperation

TL;DR

This paper develops a stochastic geometry-based model for non-coherent joint transmission in cellular networks, analyzing the impact of BS density, cooperation mechanisms, and channel estimation on network performance.

Contribution

It introduces a tractable, general model for BS cooperation considering irregular deployment, channel effects, and cooperation strategies, with analytical SINR distribution derivation.

Findings

Increasing BS density improves SINR, especially with higher path loss exponents.

Spectral efficiency saturates at about 7 BSs per cluster for typical pilot-based estimation.

Intra-cluster frequency reuse benefits moderately loaded cells with active cooperation.

Abstract

This paper presents a tractable model for analyzing non-coherent joint transmission base station (BS) cooperation, taking into account the irregular BS deployment typically encountered in practice. Besides cellular-network specific aspects such as BS density, channel fading, average path loss and interference, the model also captures relevant cooperation mechanisms including user-centric BS clustering and channel-dependent cooperation activation. The locations of all BSs are modeled by a Poisson point process. Using tools from stochastic geometry, the signal-to-interference-plus-noise ratio ($\mathtt{SINR}$) distribution with cooperation is precisely characterized in a generality-preserving form. The result is then applied to practical design problems of recent interest. We find that increasing the network-wide BS density improves the $\mathtt{SINR}$, while the gains increase with the path loss exponent. For pilot-based channel estimation, the average spectral efficiency saturates at cluster sizes of around $7$ BSs for typical values, irrespective of backhaul quality. Finally, it is shown that intra-cluster frequency reuse is favorable in moderately loaded cells with generous cooperation activation, while intra-cluster coordinated scheduling may be better in lightly loaded cells with conservative cooperation activation.