We present a novel approach for relay transmissions with multiple antennas using a decode and forward policy. The basic idea is to route the data by sending multiple independent spatial data streams directly to the destination and to different relays and then collect them at the destination. The relays are selected using an opportunistic approach in order to obtain the "multi-relay" diversity gain. Another factor of the gain is due to the fact that by splitting the streams between different relays, the effective degrees of freedom of the channel are not limited by the rank of a single link channel. We show the effectiveness of the proposed technique for fourth generation (4G) systems by using both link-level and system-level simulations.
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