Radio frequency (RF) subsampling can be used by radio receivers to directly down‐convert and digitize RF signals. A goal of a cognitive radio/software defined ratio (CR/SDR) receiver design is to place the analog‐to‐digital converter (ADC) as near the antenna as possible. Based on this, a band‐pass sampling (BPS) frontend for CR/SDR is proposed and verified. We present a receiver architecture based second‐order BPS and signal processing techniques for a digital RF frontend. This paper is focused on the benefits of the second‐order BPS architecture in spectrum sensing over a wide frequency band range and in multiband receiving without modification of the RF hardware. Methods to manipulate the spectra are described, and reconstruction filter designs are provided. On the basis of this concept, second‐order BPS frontends for CR/SDR systems are designed and verified using a hardware platform.

This paper presents an overview and novel method on inter-radar interference analysis based on propagation models and radar beam-scanning scenarios. Many studies on radar interference have provided proper methodologies and recommendations for system safety, coexistence, and higher spectrum utilization. However, the propagation models and radar beam-scanning scenarios have not given detail consideration because they usually focus on the proposed interference mitigation techniques. This paper provides a statistical interference analysis method to understand selection of propagation model and various beam-scanning scenarios on the radar interference. The time, duration, probability of the worst-case interference and expected performance degradation is presented statistically. From the simulation result, the maximum gain alignment under 1 degree between two radar occurs with 1.82 × 10 −5 probability in an example scenario. The proposed simulation and analysis method can help to derive radar operational parameters for interference mitigation and efficient spectrum utilization.

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