An Interpolation Rate Matcher for Deep Spread Spectrum Communication

Abstract

In deep spread spectrum satellite communication, because of the excessive signal bandwidth and the ADC sampling rate is limited, resulting in a low signal oversampling rate, resulting in a biggish signal timing error and a decrease in the signal-to-noise ratio of the received signal, making the communication error rate worse. In the process of digital signal processing, usually capturing signals that require two-times oversampling, and tracking signals that require eight-times oversampling, but in deep spread spectrum communication, the ADC sampling rate is limited, and it is difficult to meet the sampling rate of eight-times oversampling. Therefore, this paper designs an interpolation rate matching module, which can interpolate the signal from two-times oversampling to the equivalent of eight-times oversampling by using a 4-way interpolation matched filter when ADC performs two-times oversampling. Two-times over-sampling signals at different sampling times meet the requirements of tracking the received signal, and at the same time reduce the requirements for the signal processing clock, reduce the timing error by consuming less DSP resources, and improved the signal-to-noise ratio of the received signal.