Switching between co‐located and distributed transmit diversity
Sahar Amini, Kwonhue Choi · IET Communications · 2016
The authors propose a dual mode transmit diversity (TD) scheme switching between co‐located TD (CTD) and distributed TD (DTD) based on the quasi‐static channel parameters. The authors first compare CTD and DTD according to spatial correlation coefficient (SCC) of CTD and distributed mean channel gain (MCG) of DTD. By using asymptotic bit error rate (BER) formula, the authors derive a compact and very accurate border equation of DTD‐preferred and CTD‐preferred regions in MCG ratio and SCC space. Based on the derived border, the authors propose a dual mode TD scheme switching between CTD and DTD according to MCG ratio and SCC. It is shown that the signal‐to‐noise ratio (SNR) gain contours and the border line for TD switching are irrespective of SNR and modulation scheme. The results show that the proposed dual mode scheme outperforms the single modes not only in the location‐specific performance but also in the averaged performance over the cell area. In the averaged BER over the entire cell area, performance improvement of the dual mode scheme over CTD is significant if SCC is roughly larger than 0.6 irrespective of cell shape, spatial correlation model of CTD, path loss exponent and shadowing model.