Expanding cell coverage in cooperative base station systems by means of randomized MIMO-OFDM coding

This paper proposes a simple physical (PHY) layer design to introduce cooperation in the downlink of an infrastructure-based multicell multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) network. To improve the cell coverage, a novel PHY layer design is proposed that allows cooperation among an arbitrary and unknown number of base stations (BSs), by suitably randomizing the MIMO-OFDM block codes used by the BSs, and employs linear processing at the receiving side. Such a randomized MIMO-OFDM code renders the encoding/decoding rule independent of the number of actual BSs cooperating and works without any channel feedback, which greatly simplifies the protocol as well as the MS design. Both analytical and numerical results show the performance gain and the coverage expansion attainable.