A random access method

Abstract

The application discloses a random access method. The method comprises the following steps that: user equipment (UE) sets a cyclic shift Ncs according to a cell radius, uses the Ncs to generate a code word, and sends the code word to a network side; for each RRU in a BBU coverage range, reception data of each antenna of the RRU are respectively processed to obtain a power delay profile (PDP); if the RRU only has one antenna, user detection is carried out at a current detection window according to the PDP of the antenna; and if the RRU has a plurality of antenna, PDPs of all antennas are combined and user detection is carried out at a current detection window according to the combined PDPs, wherein the length of the detection window is obtained by the cell radius; the RRU reports related access information of the user detected in the current detection window to the BBU; and the BBU determines a current random access user based on the related access information. According to the invention, the provided method is suitable for the distributed scene with one BBU and a plurality of RRUs.

Description

technical field [0001] The present invention relates to mobile communication technology, in particular to a random access method. Background technique [0002] Distributed communication systems are widely used in practical applications, such as figure 1 The distributed communication model of the high-speed rail system shown. Users on the train communicate with the train base station through the leaked cable. The train base station can be regarded as a user equipment (UE) to communicate with the ground base station. The ground base station uses a baseband processing unit (BBU) + radio remote unit (RRU) distributed Network structure, the cells are distributed along the railway in a linear shape, the coverage of BBU is a cell, and the coverage of RRU is a sub-cell, where the number of antennas for each RRU can be configured, one BBU can carry N RRUs, and N sub-cells Merge into one cell to expand the coverage of a single cell and avoid frequent switching of train base stations...

AI Technical Summary

Problems solved by technology

This solution is not suitable for the distributed scenario of BBU+multiple RRUs, mainly because: For the distributed scenario of BBU+multiple RRUs, for example figure 1 In the high-speed rail system, the distance between the UE and each RRU is different, and the time delay of the preamble transmitted by the UE to each RRU is different. In this way, the same UE may be detected in different detection windows of different RRUs, resulting in false alarms. That is, the BBU mistakenly regards the access of one UE as the access of multiple UEs; or: for the same UE, the timing advances calculated by different RRUs are different, resulting in the situation that the UE cannot access normally

[0006] It can be seen that the random access method in the current distributed system is not suitable for the distributed scenario of BBU+multiple RRUs

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