针对已有的随机接入前导算法存在难以在实际基站中实现以及算法运算量大的缺点，文章提出了5G随机接入前导检测算法。首先将接收到的信号经过发送端的逆过程处理得到频域前导，然后生成频域ZC序列并进行分组，将各个组内频域ZC序列相加并与频域前导相关，最后通过设置阈值来检测前导序列，利用多天线分集梳理修改相对阈值的累积分布函数，根据相对检测阈值确定绝对检测阀值，即相对检测阈值与时变噪声电平的乘积。仿真结果表明，与频域固定阈值前导检测算法相比，在加性高斯白噪声信道中，所提算法的正确检测概率性能提升了1 dB；在节拍延迟线(TDLC300-100)信道中，所提算法的正确检测概率性能提升了2 dB。

Aiming at the shortcomings of the heavy computational complexity in existing random access preamble algorithm, a 5G random access preamble detection algorithm is proposed. First, the received signal is processed by the inverse process of the transmitting end to obtain a frequency domain preamble. Then a frequency domain ZC sequence is generated and grouped, and the ZC sequences in each group are correlated with the frequency domain preamble. Finally, the threshold is detected by setting a threshold. The sequence uses a multi-antenna diversity combing to modify the Cumulative Distribution Function（CDF） of the relative threshold, and determines an absolute detection threshold. The threshold is a product of the relative detection threshold and the time-varying noise level, based on the relative detection threshold. The simulation results show that compared with the frequency domain fixed threshold preamble detection algorithm, the correct detection probability performance of the proposed algorithm is improved by 1 dB in the Additive White Gaussian Noise (AWGN) channel. In the Tapped Delay Line (TDLC300-100) channel, the correct detection probability performance of the proposed algorithm is improved by 2 dB.