Cooperative hybrid cyclic delay diversity scheme in dual-hop wireless networks

Cooperative communication has been widely investigated to improve performance of wireless networks. In cooperative wireless system, various MIMO scheme such as OSTBC, CDD and V-BLAST can be easily applied and obtain diversity or multiplexing gain. These schemes cannot obtain diversity and multiplexing gain simultaneously. To guarantee both high throughput and reliable transmission, hybrid STBC can be applied. However, this typical hybrid scheme requires complex structure at the destination and generates a rate loss according to increasing the number of transmit antennas. Moreover, in cooperative wireless system, hybrid STBC is inflexible to choose relays because relays require specific STBC encoder. Therefore, in this paper, we propose the cooperative hybrid CDD scheme which can be easily applied with arbitrary number of relays without any rate loss. Furthermore, a modification is not necessary at the destination although the number of relays is changed.