The green communications concept refers to implementation of hardware or software techniques that aim to reduce energy consumption. It has given rise to the need for low complexity and low power receivers in a variety of applications. One way to achieve this objective is by fully noncoherent (no channel state information [CSI]) or partially noncoherent (partial CSI) communication. For a wireless communication system operating in a flat Rayleigh fading environment with N-branch diversity reception, and using one-sided L-level amplitude-shift keying (ASK) for data transmission, we present the decision rules for three types of low complexity and low power receivers: a fully noncoherent optimum receiver, three channel magnitude based receivers, and two channel norm based receivers. For the fully noncoherent optimum receiver, the weighted envelope detection (WENVD) receiver, the energy detection (ED) receiver (WENVD and ED receivers are channel magnitude based suboptimum receivers), and the suboptimum channel norm based energy detection receiver, analytical results on the symbol error probability minimizing optimal ASK levels are provided. Performance comparisons are made to highlight the advantages of these signaling techniques.
Ranjan K. Mallik is a Professor in the Department of Electrical Engineering, Indian Institute of Technology (IIT) Delhi and a J. C. Bose National Fellow. He received the B.Tech. degree from IIT Kanpur and the M.S. and Ph.D. degrees from the University of Southern California, Los Angeles, all in electrical engineering. He has worked as a scientist in the Defence Electronics Research Laboratory, Hyderabad, India, and as a faculty member in IIT Kharagpur and IIT Guwahati. His research interests are in diversity combining and channel modeling for wireless communications, space-time systems, cooperative communications, multiple-access systems, power line communications, molecular communications, terahertz communications, difference equations, and linear algebra. He is a recipient of the Shanti Swarup Bhatnagar Prize, the Dr. Vikram Sarabhai Research Award, the Khosla National Award (by IIT Roorkee), the Prof. P. C. P. Bhatt Faculty Research Award (by IIT Delhi), the IEI-IEEE Award for Engineering Excellence, and the J. C. Bose Fellowship. He is a member of Eta Kappa Nu, and a fellow of IEEE; TWAS; the Indian National Academies INAE, INSA, NASI, and IASc; and Asia-Pacific Artificial Intelligence Association. He served as an Area Editor and an Editor for the IEEE Transactions on Wireless Communications, and as an Editor for the IEEE Transactions on Communications. He was a Technical Program Committee Co-Chair for the Wireless Communications Symposium of GLOBECOM 2008 and ICC 2010, for the PHY Track of WCNC 2013, and for the Communication Theory Symposium of ICC 2021. He also served as the Treasurer of the IEEE Delhi Section during 2005-2006, as a member of the IEEE ComSoc Awards Standing Committee during 2015-2017, and as a member of the IEEE ComSoc Fellow Evaluation Standing Committee during 2022-2024.