naa a22 4500 510798705 CHVBK 20180411083346.0 cr unu---uuuuu 180411e20131001xx s 000 0 eng 10.1007/s11277-013-1100-5 doi (NATIONALLICENCE)springer-10.1007/s11277-013-1100-5 On the Impacts of Channel Estimation Errors and Feedback Delay on the Ergodic Capacity for Spectrum Sharing Cognitive Radio [Elektronische Daten] [Ding Xu, Zhiyong Feng, Ping Zhang] Spectrum sharing cognitive radio aims to improve the spectrum efficiency via sharing the spectrum band licensed to the primary user (PU) with the secondary user (SU) concurrently provided that the interference caused by the SU to the PU is limited. The channel state information (CSI) between the secondary transmitter (STx) and the primary receiver (PRx) is used by the STx to calculate the appropriate transmit power to limit the interference. We assume that this CSI is not only having channel estimation errors but also outdated due to feedback delay, which is different from existing studies. We derive closed-form expressions for the ergodic capacities of the SU with this imperfect CSI under the average interference power (AIP) constraint and the peak interference power (PIP) constraint. Illustrative results are presented to show the effects of the imperfect CSI. It is shown that the ergodic capacity of the SU is robust to the channel estimation errors and feedback delay under high feedback delay. It is also shown that decreasing the distance between STx and secondary receiver (SRx) or increasing the distance between STx and PRx can mitigate the impact of the imperfect CSI and significantly increase the ergodic capacity of the SU. Springer Science+Business Media New York, 2013 Cognitive radio nationallicence Spectrum sharing nationallicence Ergodic capacity nationallicence Channel estimation errors nationallicence Feedback delay nationallicence Xu Ding Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut Feng Zhiyong Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut Zhang Ping Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut Wireless Personal Communications Springer US; http://www.springer-ny.com 72/4(2013-10-01), 1875-1887 0929-6212 72:4<1875 2013 72 11277 https://doi.org/10.1007/s11277-013-1100-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11277-013-1100-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xu Ding Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut NATIONALLICENCE 700 1- Feng Zhiyong Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut NATIONALLICENCE 700 1- Zhang Ping Key Laboratory of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People's Republic of China aut NATIONALLICENCE 773 0- Wireless Personal Communications Springer US; http://www.springer-ny.com 72/4(2013-10-01), 1875-1887 0929-6212 72:4<1875 2013 72 11277 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer