CSI feedback in OFDMA wireless networks with multiple transmitter-receiver pairs

In wireless systems, multiple transmitters often need to deliver data to multiple receivers in the same interference domain. OFDMA enables interference avoidance by assigning disjoint sets of subcarriers to each transmitter. However, optimal subcarrier allocation requires CSI feedback to the transmitters, thus incurring overhead. We evaluate an allocation mechanism inspired by subcarrier switching techniques, which allows nodes to locally decide which subcarriers they prefer. Hence, feedback is minimal, as only preference values need to be shared. We implement this approach on software defined radios and compare it to standard CSI feedback mechanisms. Although our approach only requires local information, the results show that it performs close to a solution based on full CSI knowledge.