Positioning precision analysis on 5G mmWave and sub-6G signals
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摘要: 随着第五代移动通信技术(5G)的不断研发和加速商用,目前我国已建成全球最大规模的商用5G网络. 5G供应商也已逐步开始推出了基于5G 新空口(NR)的定位特性,其中高精度的5G定位技术将逐步商用. 相比4G长期演进 (LTE),5G基站密度更高,信号传输带宽更大,定位精度提升显著,有希望解决全球卫星导航系统(GNSS)在室内和城市峡谷等困难环境下的覆盖和精度问题. 介绍了5G和4G定位在测量域上的区别,分析了5G 低频Sub-6G (FR1)和高频毫米波 (FR2)的测距精度,描述了5G定位算法,并基于3GPP协议和典型商用网络配置的仿真参数来评估定位精度. 仿真结果表明:目前5G基站间时间同步误差是影响定位质量的主要因素,当时间同步精度为50 ns时,5G定位精度不到10 m;如果通过完美站间时间同步,或者在用户端附近增加定位节点以双差的方式消除时间同步误差,5G FR1可以达到约1 m的水平定位精度,而5G FR2的水平定位精度最高可以达到0.16 m.
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关键词:
- 第五代移动通信技术(5G) /
- 定位 /
- 毫米波 /
- 高精度 /
- 精度评估
Abstract: With the persistent research and rapid commercialization of 5th generation mobile communication technology (5G), China has built one of the largest commercial 5G network. Suppliers of 5G equipment start to provide new positioning features based on 5G new radio (NR). It is highly probable that the high-precision positioning technology will be gradually commercialized in the next few years. Compared with 4G long term evolution (LTE), denser network deployments and wider transmission bandwidth of 5G can bring about a significant improvement in positioning accuracy. Hopefully, 5G positioning can mitigate coverage and accuracy problems of Global Navigation Satellite Systems (GNSS) in difficult environments such as indoor and urban canyons. This article describes the differences between 5G and 4G in the measurement domain. Then the precision of Sub-6G (FR1) and high frequency mm wave (FR2) ranging measurements with Cramér-Rao bound is assessed. Followed by the description of positioning algorithms, eleven scenarios are listed with typical simulation parameters based on 3GPP specifications and commercial network configurations. The simulation results show that the precision of network synchronization is the main factor affecting the positioning quality. If the time synchronization error is 50 ns, 5G positioning precision is over 10 m. A larger bandwidth can significantly improve the ranging precision of 5G signals if the time synchronization problem can be solved by ideal synchronization or double-differencing with positioning nodes near a user end. Under ideal conditions, 5G FR1 can achieve an accuracy of about 1 m, and FR2 can achieve an accuracy of 0.16 m. -
表 1 5G定位仿真场景参数配置
场景 参数 站点数量 站间距/m 子载波间隔/kHz 信号传输带宽/MHz 定位算法 网络时间同步假设 多径假设 场景1 低频FR1 4 1000 15 50 基于TDOA的最小二乘 50 ns同步精度 无反射径测量 场景2 低频FR1 4 1000 30 100 基于TDOA的最小二乘 50 ns同步精度 无反射径测量 场景3 低频FR1 6 1000 15 50 基于TDOA的最小二乘 50 ns同步精度 无反射径测量 场景4 低频FR1 6 1000 30 100 基于TDOA的最小二乘 50 ns同步精度 无反射径测量 场景5 低频FR1 4 1000 15 50 基于TDOA的最小二乘 完美同步 无反射径测量 场景6 低频FR1 4 1000 30 100 基于TDOA的最小二乘 完美同步 无反射径测量 场景7 高频FR2 4 100 60 100 基于TDOA的最小二乘 完美同步 无反射径测量 场景8 高频FR2 4 100 120 400 基于TDOA的最小二乘 完美同步 无反射径测量 场景9 高频FR2 5 100 60 100 基于TDOA的最小二乘 完美同步 无反射径测量 场景10 高频FR2 6 100 60 100 基于TDOA的最小二乘 完美同步 无反射径测量 场景11 高频FR2 7 100 60 100 基于TDOA的最小二乘 完美同步 无反射径测量 -
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