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

We determine the exact per-user multiplexing gain (MG) of Wyner's soft-handoff network model when neighbouring transmitters and neighbouring receivers can communicate over rate-limited pipes. The per-user MG is determined, in function of the capacities of these conferencing links and of the maximum number of allowed conferencing rounds. The results reveal a certain duality between transmitter and receiver conferencing. The per-user MG remains unchanged when one exchanges the transmitter-conferencing parameters (conferencing prelog and the maximum number of permitted rounds) and the receiver-conferencing parameters. The results also show that for small conferencing prelogs (≤ 1/6), single conferencing rounds suffice to attain the maximum per-user MG when the number of conferencing rounds is unlimited. For moderate conferencing-prelogs, multiple (but finite) number of conferencing rounds are required to achieve the same per-user MG as with unlimited conferencing rounds. Finally, for large conferencing prelogs, the per-user MG saturates at a value < 1 depending on the number of allowed conferencing rounds, and every additional transmitter- or receiver-conferencing round increases the saturation level. With unlimited conferencing rounds the per-user MG is 1 when the transmitter- and receiver-conferencing-prelogs are ≥ 1/4.