Power Amplifier Predistortion Research For Massive MIMO

Increased communication services forced the communication system has a higher data transfer rate and capacity, more efficient use of spectrum is a prerequisite to achieve the purpose. Non-constant envelope modulation technique has a high spectral efficiency, it has been widely used since the 3G. RF power amplifier is an important part for a communication system, The signal having a high PAR will have a serious band adjacent channel interference and in-band distortion after because of the PA's inherent nonlinear characteristics, and therefore power amplifier linearization techniques become the research which has practical value in communication system. Digital predistortion as a linearization technique is a most promising linearization technology because of its simplicity and good stability and adaptability. The paer's achievements are as follows:First. Systematic analysis of the reasons for non-linear amplifier and the impact, analyzed the power amplifier indicators in detail, and mainly analyzed the relationship between the power amplifier and memory bandwidth of the signal. Collecting the amplifier input and output data as the source data to model the amplifier based on the actual platform, and use the model without considering memory and the model with memory to model the PA respectively, finally take the memory polynomial model as amplifier model and analyze the variety relationship between PA's characteristi and time.Second. Simulate the predistortion algorithm using LS algorithm and RLS algorithm in the Matlab soft, compare and analyze the performance of the two algorithms at the same time.Third. Based on the actual platform to verify the correctness of the predistortion algorithm, Verify the pre distortion effect of the signal that the carrier is 3.5Ghz and have different modulation types and different bandwidth.Fourth. Study spatial coupling digital predistortion algorithm.Measure the channel of indoor and outdoor using the instrument, and analysis the time characteristics of the channel, finally verify the correctnessof the algorithm indoor and get some beneficial results.