Cognitive radio is widely expected to be the next Big Bang in wireless communications. Spectrum sensing, that is, detecting the presence of the primary users in a licensed spectrum, is a fundamental problem for cognitive radio. As a result, spectrum sensing has reborn as a very active research area in recent years despite its long history. In this paper, spectrum sensing techniques from the opt...

In this paper, we analyze the performance of an energy harvesting (EH)-assisted overlay cognitive non-orthogonal multiple access (NOMA) system. The underlying system consists a primary transmitter-receiver pair accompanied by energy-constrained secondary transmitter (ST) with its intended receiver. Accordingly, ST employs time switching (TS) based receiver architecture to harvest from radio-fre...

In cognitive radio based cooperative sensing systems, some secondary users are likely to act malicious. Such secondary users are called malicious users. An optimal application of Dixon's outlier detection scheme for detecting malicious users in a cognitive radio cooperative spectrum sensing system has recently been termed as the Sliding Window Dixon's test. The Sliding window Dixon's test appli...

As the radio spectrum is becoming more and more crowded, cognitive radio has recently become a hot research topic to improve the spectrum utilization efficiency. It is well known that the success of cognitive radio depends heavily on fast and efficient spectrum sensing that is very difficult in practice. Toward this end, this paper introduces a new guard-resident cooperative spectrum sensing sc...

Spectrum sensing is studied for multi-user cognitive radio networks in this paper. An improved spectrum sensing method----energy-cooperative detection method is developed, which combines the double threshold energy detecting method with the “OR” fusion decision rule. The simulation is done for both AWGN channel and Rayleigh channel, and the advantages of the improved method are verified.

Spectrum sensing is the most significant technique in Cognitive Radio system. So in this paper for the terrestrial television broadcasting (ISDB-T) system of integrated services digital broadcasting, i develop the algorithm based energy detector with low detection delay using sequential hypothesis testing and matched filter detector of spectrum sensing used on OFDM system which is use as a prim...

Spectrum sensing is mandatory in Cognitive Radio systems, and is used in order to identify spectrum opportunities, and to guarantee that it does not cause unacceptable interference to the license owner. Since a single sensor may be in fading or shadowing, cooperative sensing among multiple sensors which experience uncorrelated fading is required to guarantee reliable sensing performance. In thi...

This paper considers the problem of spectrum sensing in cognitive radio networks when the primary user employs Orthogonal Frequency Division Multiplexing (OFDM). We develop cooperative sequential detection algorithms based on energy detectors and the autocorrelation property of cyclic prefix (CP) used in OFDM systems and compare their performances. We show that sequential detection provides muc...

This article aims to analyze a cooperative spectrum sensing scheme using a centralized approach with unreliable reporting channel. The spectrum sensing is applied to a cognitive radio system, where each cognitive radio performs a simple energy detection and send the decision to a fusion center through a reporting channel. When the decisions are available at the fusion center, a n-out-of-K rule ...

Wideband spectrum sensing is becoming increasingly important to cognitive radio (CR) systems for exploiting spectral opportunities. This paper introduces a novel multi-rate sub-Nyquist spectrum sensing (MS) system that implements cooperative wideband spectrum sensing in a CR network. MS can detect the wideband spectrum using partial measurements without reconstructing the full frequency spectru...