Wireless Personal Communications: An International Journal
Block Diagonal Differential Space---Time---Frequency Codes for Four Transmit Antennas
Wireless Personal Communications: An International Journal
Blind channel shortening in MIMO-OFDM systems using single-block differential modulation
Proceedings of the 2009 International Conference on Wireless Communications and Mobile Computing: Connecting the World Wirelessly
Unitary differential space-time-frequency codes for MB-OFDM UWB
ISCIT'09 Proceedings of the 9th international conference on Communications and information technologies
Unitary space-time modulation for single-carrier transmission over frequency-selective channels
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Differential space-time-frequency codes for MB-OFDM UWB with dual carrier modulation
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Differential quasi-orthogonal space-frequency trellis codes
IEEE Transactions on Wireless Communications
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In frequency-selective multiple-input multiple-output (MIMO) channel, differential space-time-frequency (DSTF) modulations are known as practical alternatives that are capable of exploiting the available spatial and frequency diversities without the requirement of multichannel estimation at the receiver. However, the encoding nature of the DSTF schemes that expand several OFDM symbol periods makes the DSTF schemes susceptible to fast-changing channel conditions. In this paper, we propose a differential scheme for MIMO-OFDM systems that is able to differentially encode signal within two OFDM symbol periods, and the proposed scheme transmits the differentially encoded signal within one OFDM block. The scheme not only reduces encoding and decoding delay but also relaxes the restriction on channel assumption. The successful differential decoding of the proposed scheme depends on the assumption that the fading channels keep constant over two OFDM symbol periods rather than multiple of them as required in the existing DSTF schemes. We also provide pairwise error probability analysis and quantify the performance criteria in terms of diversity and coding advantages. The design criteria reveal that the existing diagonal cyclic codes can be applied to achieve full diversity. Performance simulations under various channel conditions show that our proposed scheme yields superior performance to previously proposed differential schemes