Space-time block coding based transmit diversity

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Space-time block coding based transmit diversity (STTD) is a method of transmit diversity used in UMTS third-generation cellular systems. STTD is optional in the UTRAN air interface but mandatory for user equipment (UE). STTD utilizes space-time block code (STBC) in order to exploit redundancy in multiply transmitted versions of a signal.

A generic STTD encoder for QPSK modulation creates two sequences of STTD encoded symbols which will each be transmitted on two different antennas. If the transmitted symbols consist of b₀, b₁, b₂ and b₃, the two tranmitted sets of symbols will consist of b₀, b₁, b₂ and b₃ on antenna 1 and !b₂, b₃, b₀ and !b₁ on antenna 2, where ! denotes logical negation.

[edit] See also

• Diversity scheme
• Multiple-input and multiple-output (MIMO)
• Space diversity
• Space–time coding (STC)