It is challenging to detect and track frequency hopping spread spectrum (FHSS) signals due to their wideband frequencies and the limitations of current hardware. In the implementation, there has been a trend of conducting compressive sensing for blind signal processing of FHSS signals. The modulated wideband converter (MWC) is a type of sub-Nyquist sampling system, which accomplishes the recovery of highly accurate broadband sparse signals by multichannel sub-Nyquist sampling sequences. However, it is difficult to adjust MWC to FHSS signals, because the support set and sparsity change with the hop. In this paper, we propose a channelized MWC scheme in order to solve these problems. First, the proposed method distributes the sub-bands to different channels. We can derive and refresh the frequency support set rapidly without recovery. Secondly, by reconstructing the low-pass filter and decimation, we reduced the computational cost to 1/m as the traditional m-channel MWC scheme, where m is the number of channels. Moreover, we propose a series of strategies to estimate carrier frequency. The numerical simulations show that our method can detect the channel, which contains FHSS signals in the case of a low signal-to-noise ratio. Furthermore, the estimation method leads to the successful estimation of the FHSS carrier frequency. This indicates that our method is also effective in the broadband non-cooperative spectrum sensing.

No abstract

Most of the earlier tracking and network sorting approaches with a high sampling rate for frequency hopping (FH) signals did not adapt to the wideband system during their implementation, whereas the sub-Nyquist based algorithms cannot satisfy the real-time requirement for dealing with the rapid change of sparsity. It is important to improve the compressed sensing (CS) methods for tracking and sorting wideband FH signals. In this paper, a dynamic programming modulated wideband converters (MWC) scheme is proposed. First, considering the wide gap of FH signals, an improved power estimation method is proposed to track the support set in the time domain. Second, to sort multiple signals more effectively, a feedback control algorithm based on dynamic programming is proposed. In the proposed method, the total sampling rate is decreased significantly, and multiple FH signals are separated rapidly without recovery based on the results of tracking and comparative power. Simulations show that the proposed method can track and sort FH signals efficiently and more practically than previous methods.

No abstract

No abstract