Conferencing in Wyner's Asymmetric Interference Network: Effect of Number of Rounds

TL;DR

This paper investigates how the number of conferencing rounds affects the capacity of large interference networks, providing bounds and conditions under which maximum per-user multiplexing gain is achieved.

Contribution

It introduces bounds on per-user multiplexing gain based on conferencing link capacities and rounds, and characterizes the gain with unlimited conferencing rounds.

Findings

Single conferencing round suffices at low prelogs for maximum gain.

Additional rounds increase capacity at high prelogs.

Bounds are tight under certain symmetry and capacity conditions.

Abstract

Our goal is to study the effect of the number of conferencing rounds on the capacity of large interference networks. We do this at hand of the per-user multiplexing gain (MG) of Wyner's soft-handoff model with dedicated conferencing links between neighbouring transmitters and receivers. We present upper and lower bounds on the per-user MG of this network, which depend on the capacities of the transmitter- and receiver-conferencing links and on the number of allowed conferencing rounds. The bounds are tight when: the prelogs of the conferencing links are small or high; there is only transmitter conferencing or only receiver conferencing; or some symmetry conditions between transmitter-conferencing and receiver-conferencing hold. We also determine the per-user MG of the network when the number of conferencing rounds is unlimited. Our results show that for small conferencing prelogs around 1/6, a single conferencing round suffices to attain the maximum per-user MG when the number of conferencing rounds is unconstrained. In contrast, when the prelogs are large, then every additional conferencing round increases the maximum per-user MG.