A "Relay Node Division Duplex" Relaying Approach for MIMO Relay Networks

Recent advances in information theory have shown that the use of multiple nodes to simultaneously relay messages can further improve the capacity of source-to-destination communication. This has spurred interest in relay networks as a promising coverage extension technique. Many papers have explored the half duplex approach. This approach however limits the capacity since two time slots are required to send each message from source to destination node. To achieve higher capacity, we introduce the "relay node division duplex (RNDD)" approach, in which multiple relay nodes are divided into two groups that alternatively receive and transmit messages: while one group is receiving messages from the source node, the other is transmitting messages to the destination node. A difficulty of applying RNDD is that when the interference between the two relay groups is severe, the capacity will be greatly degraded. Therefore, we also propose a relay scheme that cancels the interference between relay groups by generating replicas of the interference from previously received signals at the destination node. Numerical results confirm that our method outperforms the conventional schemes that use the half duplex approach