基于高速移动环境的LTE上行随机接入前导序列的生成

Generation of preamble sequence in LTE uplink random access based on high-speed mobile environment

3GPP长期演进(Long Term Evolution)计划中的随机接入信道是一个基于竞争的上行信道。当某个小区内多个移动台同时发起接入时,可能发生碰撞导致部分移动台接入失败或者移动台之间相互干扰。为避免以上情况,3G LTE为不同用户接入分配了不同的前导序列,利用序列间良好的相关性避免接入冲突和用户间干扰。本论文基于3GPP对LTE上行随机接入受限循环移位前导序列的规范定义,在不改变对RACH结构假设的前提下,讨论高速移动环境下的随机接入受限循环移位前导序列,并针对两种不同的假设给出两种生成公式,并通过仿真结果比较其优劣。

The random access channel planned in 3GPP long-term evolution（ LTE） is a competition uplink channel. When more than one user in a cell trying to access at the same time, the collision could lead to the access failure of some user or mutual interference between the mobile station. In order to avoid it,3G LTE allocate different preamble sequence for different users to access, using its great correlation performance to avoid conflict and mutual interference. Based on the definition of restricted set of LTE RACH preambles set by 3GPP, without changing the assumption of the existing structure of the RACH, this paper discuss the generation of restricted random access cyclic shift preamble sequence in case of the high-speed environment, and for two different assumptions, we give formula 1 and 2, and give the comparison between them through simulation results.