Asymptotic performance of transmit diversity via OFDM for multipath channels

Abslloct-Many wimles, systems exploit transmit diversity for mom reliable detection ofsignals at the receiver. To nrrompUsh this, ceding ls spread acms multiple trsormit anteomas. An erample of this is the well known “Alamauti transmit diversity”, whcm B very simple eodiag scheme acmss multiple tramsmit iotennas allows systems to attain performance similar to systems with multiple receive sntenoar. The msjw drawback b that this system w l y works when a Vat-fading” model for tho channel Is assumed; when used in a multipath environment, the system breaks dmn. Hero we show that when the Alrmouti rode i s placed within an OFDM strnchlre, using adjacent frequency bands rathw than ronsrrutive symbol intends, it can PsymptoticaUy achieve the same petfomance In multipath fsdiog as the Alamouti eodeb Rat-fading. Keyvodstransmit diversity, OFDM, frequency selective fsding, multipath, molticnrrier.