Design of a cooperative OFDM transceiver

We present the FPGA implementation of a MIMO and cooperative OFDM physical layer transceiver. Our transceiver is designed to support multiple antenna configurations, including SISO (single-antenna), receive switching diversity, transmit diversity using Alamouti's space-time block code and 2×2 spatial multiplexing. It also supports a fully-distributed physical layer cooperation scheme which allows two nodes to simultaneously transmit a common payload, achieving spatial diversity with only single-antenna transmissions. Our transceiver supports the common cooperative scheme of amplify-and-forward and provides a flexible interface for higher layers to enable cooperation as needed. The transceiver is implemented as a single FPGA core with a common datapath for all modes. This allows both efficient resource reuse between modes and a per-packet selection of antenna mode. This flexibility enables a wide variety of MIMO and cooperative protocols. We present architectural details of the cooperative transceiver design and early performance results using Rice University's Wireless Open-Access Research Platform (WARP).