A new diversity scheme for frequency selective MIMO channels

This paper presents a new diversity scheme for quasi-static wireless MIMO channels. In the proposed scheme, an innovative pre-coding/framing mechanism is employed to translate a multiple-input multiple-output (MlMO) frequency-selective channel into a mathematically equivalent single-input multiple-output (SIMO) channel. Consequently, the conventional trellis codes designed for fast fading channels can be used to exploit diversity in both spatial and frequency domains. It was shown that the diversity gain of the proposed scheme equals the effective length of the conventional trellis codes used. This is in contrary to the case of space-time coded OFDM (STC-OFDM) where no systematic methods exist for the design of space-time trellis codes with a given target of diversity gain. Simulations have been carried out and results are given to show the merits of the proposed scheme.