By using new DSTBC in OFDM communications system channel estimation is nto necessary and coding gain is gotten.

通过在OFDM通信系统中应用新型差分空时分组码（DSTBC），获得编码增益，无需信道估计。

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The traditional differential space-time block code (DSTBC) suffers from the signal constellation expansion for QPSK modulation.

传统的差分空时分组编码(DSTBC)在QPSK调制时存在着信号星座扩展。

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