Open-loop diversity technique for systems employing multi-transmitter antennas

摘要

A method and apparatus for increasing the capacity of a system that use four transmit antennas and that employs conventional channel coding by performing space-time coding in a particular way. Each of two pairs of symbol sub-streams is space-time coded to form a respective pair of transmit-sequence chains, where at least one of the formed pairs of the transmit-sequence chains is a function of symbols of the respective symbol-sub-stream pair and not a function of the symbols of the other symbol-sub-stream pair. Four transmit sequencestwo transmit sequences from each of the two pairs of symbol sub-streamsmay be viewed as forming a transmission matrices B or B arranged as follows: $\mathop{\mathrm{image}}\text{\ }\⁢T_1\⁢\text{\ }\⁢T_2\⁢\text{\ }\⁢T_3\⁢\text{\ }\⁢T_4\begin{array}{cc}\mathrm{Antenna}& 105-1\\ \mathrm{Antenna}& 105-2\\ \mathrm{Antenna}& 105-3\\ \mathrm{Antenna}& 105-4\end{array}\⁡\left[\begin{array}{cccc}{b}_1& b_1& -b_2^{*}& -b_2^{*}\\ b_2& b_2& b_1^{*}& b_1^{*}\\ b_3& -b_3& -b_4^{*}& b_4^{*}\\ b_4& -b_4& b_3^{*}& -b_3^{*}\end{array}\right]\⁢\text{\ }\⁢\mathrm{or},\text{\
}\⁢\text{\ }\⁢T_1\⁢\text{\ }\⁢T_2\⁢\text{\ }\⁢T_3\⁢\text{\ }\⁢T_4\begin{array}{cc}\mathrm{Antenna}& 105-1\\ \mathrm{Antenna}& 105-2\\ \mathrm{Antenna}& 105-3\\ \mathrm{Antenna}& 105-4\end{array}\⁡\left[\begin{array}{cccc}{b}_1& -b_2^{*}& 0& 0\\ b_2& b_1^{*}& 0& 0\\ 0& 0& b_3& -b_4^{*}\\ 0& 0& b_4& b_3^{*}\end{array}\right]\⁢\text{\ },$;respectively, where b₁, b₂, b₃, and b₄ are the symbols derived from a respective one of four symbol sub-streams, and b*₁, b*₂, b*₃, and b*₄ are, respectively, the complex conjugate of the aforementioned symbols. The rows of the matrix represent the different antennas, while the columns represent different symbol periods.