Error probability bounds for interference-limited cooperative networks

We consider a multi-cell cooperative network where a cluster of base stations jointly detect the signals from multiple users transmitting within the cluster. Different from previous works, we examine the impact of interference from out-of-cluster users whose transmit power scales with that of the in-cluster users. For such a network, we derive new upper and lower bounds on the uncoded bit error probability (BEP) of the in-cluster users with independent Rayleigh fading and arbitrary path loss. We observe that our lower bound accurately approximates the BEP at low signal-to-noise ratios (SNRs), whereas the upper bound is accurate at high SNRs. Our analytical bounds accurately characterize the impact of out-of-cluster interference and cluster size on the BEP. Specifically, we highlight that out-of-cluster interference results in a BEP saturation regime when the transmit power is large. We also show that the saturation threshold increases with the cluster size.