Modification of the D-TxAA Scheme for Fading Channel

The D-TxAA scheme was adopted by 3 GPP as standard for HSDPA MIMO. However, the performance of this scheme significantly decreases under the conditions of fading channel due to loss of mutual orthogonality between streams in fading. In this paper the modification of the original D-TxAA scheme is proposed which allows to improve the performance in fading channel. This improvement was achieved by means of using the additional STTD encoding on top of D-TxAA scheme, which leads to some theoretical performance decrease in static channel. The modified scheme is proposed to be used as optional mode in MIMO HSDPA.