Optimal multiuser detection in a cooperative two-cell network

We derive new theoretical bounds on the minimum bit error probability (BEP) of optimal multiuser joint detection in the uplink of a cooperative cellular network. To identify key insights, we consider the basic two-cell cooperative scenario where the signals transmitted by two users are jointly detected at two base stations. For such a network, we derive closed-form expressions for upper and lower bounds on the minimum BEP with independent Rayleigh fading and path loss between the users and the base stations. We further evaluate these expressions asymptotically to characterize the diversity order at high signal-to-noise ratios (SNRs). We observe that the lower bound accurately approximates the BEP simulation at low SNRs while the upper bound is accurate in the medium to high SNRs.