Cross correlation mitigation algorithm for indoor positioning receiver

Abstract

In recent years, the location based service has been gradually integrated into people’s daily life. Many fields such as the public security, emergency rescue, warehousing logistics, and IOT (The Internet of things) applications present extensive application demand on indoor location. This paper discusses the cross correlation interference in the TC-OFDM (time divided CDMA-OFDM superimposed signal system) receiver which is based on ground mobile radio network. In the TC-OFDM system, because of the complexity of the indoor environment, multiple access interference is terrible, which greatly affects the performance of the receiver for signal acquisition and tracking. This paper studies the characteristics of the multiple access interference in TC-OFDM system in indoor environment. The cross correlation value between the strong and weak signal can be estimated by putting the characteristic information of strong signal into the weak signal tracking channel. While this information can be extracted from the strong signal’s tracking channel. Therefore, strong signal’s effection on the weak signal’s autocorrelation function can be reduced. So that the tracking loop can get more accurate phase value for tracking. This method can improve the TC-OFDM receiver’s ability of inhibiting cross correlation by 10–13 dB, and effectively enhance the capacity for sustained and stable tracking of weak signal. In addition, in the snapshot replay mode of the weak signal which cannot be tracked continuously, this method helps to estimate the correlation peak more accurate.