Stability of transmitter cooperation over a multiple access channel

Cooperation between nodes has become increasingly necessary to mitigate interference in modern wireless networks. The question of whether cooperation is fair and stable and whether all rational nodes have a sufficiently large incentive to cooperate is unknown even for simple networks. This paper addresses the stability of cooperation between rational transmitters (TXs) signaling over a multiple access channel (MAC) using the framework of cooperation game theory. Using the sum rate as the utility of each coalition of TXs, the stability of the grand coalition is examined by evaluating the core of the TX game cooperation game in partition form, a game model in which the utility of a coalition depends on TXs external to the coalition. The non-emptiness of the core implies that there exists a feasible division of utility such that no smaller coalition of TXs has an incentive to deviate from the grand coalition. For a single user decoding (SUD) receiver, the cooperation is shown to be stable in the high SNR and low SNR regimes while for a successive interference cancelling (SIC) receiver with fixed decoding order, cooperation is stable only in the low SNR regime.