Space Frequency/Space Time Frequency Code Based On Rotation Transformation And Orthogonal Construction

The need of high data rate and high performances promotes the development and applications of many new high speed wireless communication techniques. The combination of multiple-input multiple-output (MEMO) wireless technology with orthogonal frequency division multiplexing (OFDM) has recently received considerable attentions, which can not only effectively enhance the transmission rate and capacity of the wireless communication system but also effectively combat multi-path fading and interfere. This paper dedicated to appling space time code, which is one of the core technologies of MIMO systems to MIMO-OFDM systems, in order to obtain higher coding and diversity gain, as well as the low complexity decode. The main work and contributions of the dissertation are in the several aspects as follows:1. The space time code in MIMO systems and traditional STC and SFC in MIMO-OFDM systems are present at first, and then the simulitaion of these algorithms's differences is given.2. Based on rotation transformation and every two antennas orthogonal design, a rate-one SFC technology for MIMO-OFDM systems over frequency selective fading channels is designned. The full-diversity gain and maximum coding gain proved from the theoretical analysis and validated from the simulation results. More over the SFC can be decoded by sphere-decoding algorithm, which has lower complexity.3. In order to obtain maximum coding and full diversity gain in space, time and frequency for MIMO-OFDM systems, a space-time-frequency code design criteria is given and a rate-one full diversity space-time-frequency code based on rotation transformation and orthogonal design is present. The data streams are first rotated by an algebraic rotation matrix, and then designed orthogonal every two antennas in two OFDM blocks. The STF code can also be decoded by the lower complexity sphere-decoding algorithm to performer the Maximum-likelihood decoding algorithm after linear combination and whitened processing. More over The STF code performance is also proved from theoretical analysis and simulation results.