Received: 25 June 2018 Revised: 20 December 2018 Accepted: 27 December 2018 DOI: 10.1002/ett.3566 RESEARCH ARTICLE MGF-based analysis of -/gamma composite fading model for indoor off body communication Hari Shankar 1 Ankush Kansal 2 1 Research Scholar, Thapar Institute of Engineering and Technology, Patiala, India 2 Thapar Institute of Engineering and Technology, Patiala, India Correspondence Hari Shankar, Research Scholar, Thapar Institute of Engineering and Technology, Patiala-147004, India. Email: hari.shankar55@gmail.com Abstract This paper presents the moment generating function (MGF)–based analysis of κ-μ/gamma composite fading model, which is suitable for the indoor off-body communication channel. In this paper, first of all, we derive an analytical expression for MGF of instantaneous signal-to-noise ratio. By using the derived MGF, the expressions of average symbol error rate (ASER)/average bit error rate (ABER) for binary and M-ary modulation scheme are derived. Using the MGF approach, we also derive the expression of channel capacity for optimum rate adaption and channel inversion with fixed rate policy. The derived expressions for ABER/ASER and channel capacity are presented in the infinite series form. We further present the numerical results of error rate and channel capacity for different values of κ, μ, α, and β parameters. The result of ABER and channel capacity shows good agreement with the previously reported results as special cases that verify the derived expressions. 1 INTRODUCTION The composite or shadowed fading model is suitable for those scenarios where multipath fading superimposes on shadow- ing. In the last two decades, various composite fading models have been proposed. 1 Depending on the path of obstruction, the shadowed fading model can be defined in two ways: line of sight (LOS) 2-6 and multiplicative shadowed 7-12 fading model. The former is the cause of random variation in the dominant signal component. However, due to multiplicative shadowing, the random fluctuation occurs in total signal power component, ie, both dominant and diffuse power compo- nent. Recently, the multiplicative shadowed fading model, known as κ-μ/gamma, has been proposed by Yoo et al, 12 which was initially proposed by Sofotasios and Freear. 13 The study on body-centric communication (BCC) is interesting because it includes many applications in the fields of communication, sports, military, medical, entertainment, etc. In BCC systems, at least one wireless link is worn on the human body. Depending on the position of transmitter and receiver, the BCC can be defined into three-way: body-to-body (B2B), on-body, off-body communications. In off-body communication, at least one or more devices are worn on the human body and another device may be placed on the top floor of the building (base station/gateway device). In on-body communication, one or more wireless devices are placed on the human body. However, in B2B communication, one wireless device is placed on a human body and another one is placed on another human body. 3,12 The performance analysis over composite fading channel has a significant role to design the digital wireless commu- nication system. The performance analysis parameter such as ABER, outage probability, and channel capacity can be obtained by using either the moment generating function (MGF)–based approach or the probability density function (PDF)–based approach. The PDF-based performance analysis is complicated and, generally, the solution is not presented Trans Emerging Tel Tech. 2019;e3566. wileyonlinelibrary.com/journal/ett © 2019 John Wiley & Sons, Ltd. 1 of 17 https://doi.org/10.1002/ett.3566