High diversity with simple space time block-codes and linear receivers

Multiple-input-multiple-output (MIMO) systems are under intense investigation for wireless transmission systems. Space-time coding is an efficient approach to exploit the huge diversity offered by the MIMO channel. One of the main problems of space-time block coding (STBC) is that the offered diversity can only be exploited by the optimal ML receiver which has exponential complexity. In contrast, linear receivers like the ZF-receiver are less complex, but achieve in general only a fraction of the offered diversity. In this paper, we show that it is also possible to achieve high diversity with linear receivers utilizing STBCs with a specific structure. We investigate the diversity properties of cyclic codes and extended Alamouti codes. It is shown, that the diversity order D increases asymptotically linear with the number of receive antennas (n/sub R/) and that the extended Alamouti code achieves already almost full diversity utilizing linear receivers and only small n/sub R/.