Physical random access channel (PRACH) signal generation method

Abstract

The invention relates to a physical random access channel (PRACH) signal generation method. The method comprises steps: random access channel parameters and preamble sequence parameters sent by a base station are received; the random access channel parameters are used for calculating the offset of a center frequency point; a first sampling frequency of a digital to analog conversion chip is reduced to a second sampling frequency; the preamble sequence parameters are used for generating a ZC sequence, discrete Fourier transform operation is carried out on the ZC sequence, and a frequency domain signal is obtained; according to the second sampling frequency, inverse fast Fourier transform operation is carried out on the frequency domain signal, and a time domain signal is obtained; according to the offset of the center frequency point, a first center frequency point of a radio frequency chip is adjusted to a second center frequency point; and according to the second center frequency point, the time domain signal is sent. According to the method provided by the invention, in view of signal features of the PRACH, in a mode of combining direct sampling frequency reduction and center frequency point adjustment, the operation quantity, the processing time delay and the data cache generated by the PRACH signal are greatly reduced and the method is simple and high-efficiency.

Description

technical field [0001] The present application relates to the field of communication technologies, and in particular to a method and device for generating a Physical Random Access Channel (Physical Random Access Channel, PRACH) signal of a Long Term Evolution (Long Term Evolution, LTE) system. Background technique [0002] In the random access process of the LTE system, the terminal needs to complete the generation of the preamble sequence and the baseband signal. According to the agreement, the generation of the analog baseband signal can be regarded as two parts: the discrete Fourier transform (DFT) of the ZC (Zadoff-chu) sequence length point preamble sequence and the fast Fourier transform of the time period point of the preamble sequence Inverse leaf transform (Inverse fast Fourier transform, IFFT). For example, under 20M bandwidth, the length of the preamble sequence whose preamble format is zero is 24576, and PRACH signal generation needs to do IFFT of 24576 points a...

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Problems solved by technology

[0004] The purpose of this application is to provide a physical random access channel signal generation method, which solves the problem of large amount of data computation and long processing time during the signal generation process of the PRACH channel by directly reducing the sampling frequency and adjusting the center frequency point. The problem of taking up a lot of storage space

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