Medium-frequency crest suppression method and system for time-division synchronization code division-multiple-access system

Abstract

The disclosed MF peak-removing method in TD-SCDMA system comprises: a. receiving digital up-conversion signal, and deciding whether the signal peak over the first threshold; b. if yes, selecting peakdirectional code slice according to the baseband signal; c. generating the peak-removing signal; and d. subtracting the up-conversion signal with the peak-removing signal for output. This invention has little effect on ACLR, affects EVM and BER a little, and has high efficiency.

Description

technical field [0001] The invention relates to a TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) mobile communication system, in particular to a technique for reducing peak-to-average ratio in TD-SCDMA. Background technique [0002] TD-SCDMA intermediate frequency implementation has the following agreement for N-frequency point cells: the baseband 1.28Mcps (megachips per second) signal is oversampled by 60 times to 76.8Mcps, and then modulated to the main carrier frequency of about 96MHz, and the auxiliary carrier frequency is the main carrier frequency ±1.6MHz, RF shares a set of transmitters. [0003] In the TD-SCDMA system N-frequency point cell agreement, multiple carriers in a cell are combined after the digital intermediate frequency spectrum shift, and RF (Radio Frequency, radio frequency) shares a set of transmitters, so that it will appear at the antenna transmitting end. Since the peak-to-peak superposition produces a strong signal peak-to-aver...

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Problems solved by technology

[0010] However, in the TD-SCDMA standard multi-carrier system, the time slot has its particularity, and the block coding method is very complicated to implement, and it is difficult to be practical; the clipping method cuts or compresses the carrier with a large amplitude or all carriers to reduce The peak-to-average ratio has a great impact on system performance and has little improvement on ACLR; the selection sequence method is complicated to implement, and the spread spectrum sequence should not be easily changed; although the amplitude and phase variation method does not produce nonlinear distortion, if you want to make After each rotation, the peak-to-average ratio is optimal, a large number of calculations must be performed and sideband information needs to be transmitted, the delay is large and the processing is complicated, and the transmission of sideband information is also prone to error diffusion; although the ordinary time-domain digital interpolation method Can find peaks more accurately and eliminate them, but the efficiency is low

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