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

Abstract

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 sequences—two transmit sequences from each of the two pairs of symbol sub-streams—may be viewed as forming a transmission matrices B or B′ arranged as follows: 1 ⁢ T 1 ⁢ ⁢ T 2 ⁢ ⁢ T 3 ⁢ ⁢ T 4 Antenna 105 - 1 Antenna 105 - 2 Antenna 105 - 3 Antenna 105 - 4 ⁡ [ 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 * ] ⁢ ⁢ or , ⁢ ⁢ T 1 ⁢ ⁢ T 2 ⁢ ⁢ T 3 ⁢ ⁢ T 4 Antenna 105 - 1 Antenna 105 - 2 Antenna 105 - 3 Antenna 105 - 4 ⁡ [ b 1 - b 2 * 0 0 b 2 b 1 * 0 0 0 0 b 3 - b 4 * 0 0 b 4 b 3 * ] ⁢ , 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.

Dependencies are inferred from the claim text.