An effective technique to improve wireless communication performance is transmit diversity.In this transmitter diversity using a new combination of space-time block codes (STBCs) concatenated with orthogonal frequency division.

Differential Space-Time-Frequency Codes for MB-OFDM UWB with Dual Carrier Modulation

Quasi-Orthogonal Space-Time-Frequency Trellis Codes for MIMO-OFDM Systems