On the fundamental limits of cooperative multiple-access channels with distributed CSIT

Miretti, Lorenzo; de Kerret, Paul; Gesbert, David
ITW 2019, IEEE Information Theory Workshop, 25-28 August 2019, Visby, Gotland, Sweden

The availability of accurate and, most importantly, shared channel state information at the transmitter (CSIT) is one of the key factors that enable transmitters cooperation in
decentralized wireless systems. However, in some cases, channel information may not be easily or perfectly shared among the transmitters, thus limiting their coordination capabilities. In this paper we shed some light on the fundamental limits of
networks with cooperating transmitters impaired by a general distributed CSIT assumption. To this end, we consider a statedependent memory-less multiple-access channel with common message, and with noisy causal CSIT and noisy channel state
information at the receiver (CSIR). Perhaps surprisingly, and in contrast to the same setting in absence of common message, we show that distributed precoding based on current CSIT only (namely, a Shannon strategy) achieves the sum-rate capacity of
this channel, for every degree of CSIT and CSIR. By focusing on the transmission of a common message only, we then illustrate this result in a practically relevant Gaussian setting.

Communication systems
Eurecom Ref:
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