Transmit diversity options for GSM/EDGE

High system capacity is of utmost importance for future GSM/EDGE networks, with increasing attention given to improved downlink performance. One performance enhancing feature for the downlink is transmit diversity, where the base station transmits from multiple antennas. This paper studies the transmit diversity schemes delay diversity, antenna hopping and phase hopping, which can be used for all existing terminals. Antenna hopping is shown to be very attractive for the non-frequency hopping traffic channels, while delay diversity is an interesting technique for the frequency hopping channels. In an interference limited network, however, it is shown that for terminals with advanced receiver algorithms for interference suppression the performance gains may be reduced if interfered by a base station employing delay diversity.