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See detailExperimental Study of an Underlay Cognitive Radio System: Model Validation and Demonstration
Becker, Hanna; Kaushik, Ankit; Sharma, Shree Krishna UL et al

in Proceedings of CROWNCOM 2016 (2016, May)

Cognitive radio is one of the potential contenders that address the problem of spectrum scarcity by making e efficient use of the currently allocated spectrum below 6 GHz. A secondary access to the ... [more ▼]

Cognitive radio is one of the potential contenders that address the problem of spectrum scarcity by making e efficient use of the currently allocated spectrum below 6 GHz. A secondary access to the licensed spectrum is only possible, if the cognitive radio systems restrict the interference to the primary systems. However, the performance analysis of such a cognitive radio system is a challenging task. Currently, performance evaluation of underlay systems is limited to theoretical analysis. Most of the existing theoretical investigations make certain assumptions in order to sustain analytical tractability, which could be unrealistic from the deployment perspective. Motivated by this fact, in this work, we validate the performance of an underlay system by means of laboratory measurements, and consequently propose a hardware demonstrator of such a system. Moreover, we present a graphical user interface to provide insights to the working of the proposed demonstrator and highlight the main issues faced during this experimental study. [less ▲]

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See detailPerformance Analysis of Hybrid Cognitive Radio Systems with Imperfect Channel Knowledge
Kaushik, Ankit; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of International Conference on Communications (ICC) (2016, May)

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the ... [more ▼]

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the Secondary Transmitter (ST). Existing baseline models considered for performance analysis assume perfect knowledge of the involved channels at the ST, however, such situations hardly exist in practical deployments. Motivated by this fact, we propose a novel approach that incorporates channel estimation at the ST, and consequently characterizes the performance of Hybrid Systems (HSs) under realistic scenarios. To capture the impact of imperfect channel knowledge, we propose outage constraints on the detection probability at the ST and on the interference power received at the primary receiver. Our analysis reveals that the baseline model overestimates the performance of the HS in terms of achievable secondary user throughput. Finally, based on the proposed estimation-sensing-throughput tradeoff, we determine suitable estimation and sensing durations that effectively capture the effect of imperfect channel knowledge and subsequently enhance the achievable secondary user throughput. [less ▲]

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See detailEstimation-Throughput Tradeoff for Underlay Cognitive Radio Systems
Kaushik, Ankit; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of International Conference on Communications (ICC) (2015, June)

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See detailSensing-Throughput Tradeoff for Cognitive Radio Systems with Unknown Received Power
Kaushik, Ankit; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of CROWNCOM 2015 (2015, April)

Understanding the performance of the cognitive radio systems is of great interest. Different paradigms have been extensively analyzed in the literature to perform secondary access to the licensed spectrum ... [more ▼]

Understanding the performance of the cognitive radio systems is of great interest. Different paradigms have been extensively analyzed in the literature to perform secondary access to the licensed spectrum. Of these, Interweave System (IS) has been widely investigated for performance analysis. According to IS, sensing is employed at the Secondary Transmitter (ST) that protects the Primary Receiver (PR) from the interference induced. Thus, in order to control the interference at the PR, it is required to sustain a certain level of probability of detection. In this regard, ST requires the knowledge of the received power. However, in practice, this knowledge is not available at the ST. Thereby performing analysis considering the prior knowledge of the received power is too idealistic, thus, do not depict the actual performance of the IS. Motivated by this fact, an estimation model that includes received power estimation is proposed. Considering a sensing-throughput tradeoff, we apply this model to characterize the performance of the IS. Most importantly, the proposed model captures the estimation error to determine the distortion in the system performance. Based on analysis, it is illustrated that the ideal model overestimates the performance of the IS. Finally, it is shown that with an appropriate choice of the estimation time, the severity in distortion can be effectively regulated. [less ▲]

Detailed reference viewed: 102 (9 UL)