Cross-Layer Combining of Adaptive Modulation and Truncated ARQ Under Cognitive Radio Resource Requirements

• Published in: IEEE transactions on vehicular technology Vol. 61; no. 9; pp. 4020 - 4030
• Main Authors: Yuli Yang, Hao Ma, Aissa, S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.11.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive modulation and coding (AMC); Applied sciences; Automatic repeat request; automatic repeat request (ARQ); Channels; Coding, codes; Cognitive radio; cognitive radio (CR); Communication channels; cross-layer design; Exact sciences and technology; Fading; Information, signal and communications theory; Joints; Links; Modulation; Modulation, demodulation; Networks; packet error rate (PER); packet loss probability (PLP); Packet transmission; Physical layer; Probability density function; Probability density functions; Radiocommunication specific techniques; Radiocommunications; Signal and communications theory; Signal to noise ratio; spectral efficiency (SE); spectrum sharing; Strontium; Studies; Switching and signalling; Switching theory; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmitter; Data transmission; cognitive radio (CR); packet loss probability (PLP); Packet error rate; Power allocation; Time variation; Addressing; packet error rate (PER); Linear prediction; Optimal allocation; cross-layer design; Cross-layer approach; spectral efficiency (SE); Probability density function; Adaptive modulation; Data link; Modulation coding; spectrum sharing; Packet switching; Resource sharing; Adaptive coding; Statistical method; High efficiency; Adaptive modulation and coding (AMC); Transmission mode; Transmission loss; automatic repeat request (ARQ); Automatic repeat request; Radio communication; Software radio; Signal to noise ratio
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2012.2214410

In addressing the issue of taking full advantage of the shared spectrum under imposed limitations in a cognitive radio (CR) network, we exploit a cross-layer design for the communications of secondary users (SUs), which combines adaptive modulation and coding (AMC) at the physical layer with truncated automatic repeat request (ARQ) protocol at the data link layer. To achieve high spectral efficiency (SE) while maintaining a target packet loss probability (PLP), switching among different transmission modes is performed to match the time-varying propagation conditions pertaining to the secondary link. Herein, by minimizing the SU's packet error rate (PER) with each transmission mode subject to the spectrum-sharing constraints, we obtain the optimal power allocation at the secondary transmitter (ST) and then derive the probability density function (pdf) of the received SNR at the secondary receiver (SR). Based on these statistics, the SU's packet loss rate and average SE are obtained in closed form, considering transmissions over block-fading channels with different distributions. Our results quantify the relation between the performance of a secondary link exploiting the cross-layer-designed adaptive transmission and the interference inflicted on the primary user (PU) in CR networks.