Krzysztof Cichon

Energy-Efficient Cooperative Spectrum Sensing: A Survey

The article analyzes the problem of energy efficient techniques in cooperative spectrum sensing (CSS). Although it was proven that single-device sensing is not sufficient for reliable sensing, cooperative spectrum sensing was proposed, burdened, however, with great overhead. Thus, work on the topic of energy efficient cooperative schemes gained more interest, which resulted in a number of energy efficient cooperative algorithm proposals. In this work, we try to classify the possible directions in energy efficient CSS and present a limited set of works introducing new ideas to an energy efficient CSS algorithm.

An energy-efficient cooperative spectrum sensing

In this work, the energy consumption in the cooperative spectrum sensing is analysed. The analysis also covers the detection quality assessment and the definition of the energy efficiency (EE) metric. It is shown how cooperation among the sensing nodes affects the EE and how relaying of sensing information and node selection influences the detection probability and energy consumption. Simulation results prove that the EE of cooperative sensing depends on the link quality, the distance between node and Fusion Centre or Primary User as well as of the density of nodes in network.

The impact of hardware implementation on the performance of spectrum sensing algorithms

The problem of efficient hardware implementation of a reliable spectrum sensing method is crucial for the practical realization of the cognitive radio terminal. This paper analyses the influence of various hardware implementation issues on the performance of the sequential energy-detection-based spectrum sensing algorithm. In particular, the necessity of noise inclusion in noise variance estimation is discussed. Furthermore, based on the experiments conducted with the USRP N210 board used for the detection of a wireless microphone, the impact of numerous unwanted phenomena on the reliability of the spectrum sensing algorithm is also presented. It has been stated that such effects can influence not only noise-power dependent methods, but also the algorithms of other classes.

Energy-efficient cooperative spectrum sensing with a merged clustering measure

The article presents an analysis of correlation-based clustering procedure in cooperative spectrum sensing. The motivation is to assess if it is more beneficial in terms of energy efficiency to group nodes according to the received signal-to-noise ratio (SNR) on the link between Primary User and node or according to the distance between nodes. To this end, a merged clustering measure is introduced. Then a number of network topologies are compared via computer simulations.

Performance aspects of cooperative spectrum sensing in hardware implementation

The problem of efficient hardware implementation of spectrum sensing algorithm is still highly investigated. In this paper the double-threshold energy-detection algorithm was analysed, which effectiveness was tested with the cooperative use of USRP platforms. In the real-time experiments a set of sensing nodes check continuously the occupancy of the frequency band, trying to detect the presence of DVB-T or PMSE signals. The obtained results showed that cooperative spectrum sensing have to tackle with hardware limitations and noise uncertainty.