基于MLS的NB-IoT系统下行信道估计算法

Downlink Channel Estimation Algorithm of NB-IoT System Based on MLS

窄带物联网(NB-IoT)是3GPP针对低功耗、广覆盖类业务定义的新一代蜂窝物联网技术,是实现万物互联的重要技术之一,而信道估计则是NB-IoT终端能否准确恢复发射信号的基础。通过对NB-IoT中基于导频的下行信道估计算法进行研究,提出基于移动最小二乘法(MLS)的信道插值估计算法。在发射端插入导频信号,根据接收端的信号计算导频点信道参数,并引入紧支的概念,利用附近子域对导频点的影响权重估计信道参数。仿真结果表明,与线性插值和二次插值算法相比,采用该算法进行信道估计系统误码率较低,并且算法的计算复杂度也未显著增加。

The Narrow Band Internet of Things(NB-IoT),as a new generation of cellular IoT technology defined by the 3rd Generation Partnership Project(3GPP)for low-power and wide-coverage services,is one of the key technologies for achieving the Internet of Everything.Channel estimation technique is the key to whether the NB-IoT terminal can accurately and effectively recover the transmitted signal.This paper conducts a study on the pilot-based downlink channel estimation algorithm in NB-IoT,and proposes a channel interpolation estimation algorithm based on Movable Least Squares(MLS).The pilot is inserted in the transmitting terminal,and the pilot point channel parameters are calculated according to the signals in the receiving terminal.After that,the concept of compact support is introduced,and the channel parameters are estimated by using the nearby sub-domains to influence the weight of the pilot points.Simulation results show that compared with the traditional linear interpolation and quadratic interpolation algorithms,the bit error rate of the proposed algorithm is lower while the computational complexity is not significantly increased.