Low SNR — When only decoding will do

We investigate the issue of distributed receiver cooperation in a multiple-relay network with memoryless independent fading channels, where the channel state information can´t be obtained. The received signals at distributed receiving nodes are first compressed or quantized before being sent to the decoder via rate-limited cooperation channels for joint processing. We focus on the low SNR regime and analyze the capacity bounds using network equivalence theory and a multiple-layer binning peaky frequency shift keying (FSK). When the received signals at the relaying nodes are in low SNR regime and the cooperation rates are not sufficiently high, compressed/quantized observations at relaying nodes become useless and only decoding can help.