Throughput of Cellular Systems with Conferencing Mobiles and Cooperative Base Stations

This paper considers an enhancement to multi-cell processing for the uplink of a cellular system, whereby the mobile stations are allowed to exchange messages on orthogonal channels of fixed capacity (conferencing). Both conferencing among mobile stations in different cells and in the same cell (inter and intra-cell conferencing, respectively) are studied. For both cases, it is shown that a rate-splitting transmission strategy, where part of the message is exchanged on the conferencing channels and then transmitted cooperatively to the base stations, is capacity-achieving for sufficiently large conferencing capacity. In case of inter-cell conferencing, this strategy can be regarded as able to perform convolutional pre-equalization of the signal encoding the common messages in the spatial domain, where the number of taps of the finite-impulse response equalizer depends on the number of conferencing rounds. Analysis in the low signal-to-noise ratio regime and numerical results validate the advantages of conferencing as a complementary technology to multi-cell processing.