MIMO OFDM system with AMC and variable CP length for wireless communications

There are a few core technologies to enable high-performance 4
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generation (4G) broadband wireless communication system. A multiple input multiple output (MIMO) provides high-rate transmission through expended channels by multiple array antennas in both sender and receiver side. Also orthogonal frequency division multiplexing (OFDM) is well-known as the most appropriate technique for high data rate transmission. Adaptive modulation and coding (AMC) changes a modulation order and coding rate according to channel conditions, so it is possible that the spectral efficiency is improved at the fixed error performance. Cyclic prefix (CP) is the one of the most important technique to OFDM system and is reducing inter-symbol interference (ISI) effects in high speed wireless mobile communication system. As consider the time varying channel condition, however, fixed CP length is not only increasing power consumption but also reducing data transmission rate. In this paper, we propose a multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with AMC and adaptive CP length to improve system capacity with maintaining good error performance. The results of computer simulation show the improvement of system capacity in Rayleigh fading channel.