CSI Feedback in OFDMA Wireless Networks with Multiple Sender-Receiver Pairs

Abstract

In wired or wireless distribution systems, as well as wireless mesh networks, multiple senders 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 sender. However, optimal subcarrier allocation requires CSI feedback to the transmitters, thus in-curring overhead. We evaluate an allocation mechanism inspired in 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. Despite our approach only requires local information, the results show that it performs close to an ideal solution based on full CSI knowledge.