Source‐sum‐power minimization in multiple‐sensor single‐AF relay‐based IoT networks with outage constraints and under hardware impairments and imperfect CSI

Abstract

This paper investigates the optimal power allocation to minimize the sourcesum-power consumption of Internet of Things networks in the presence of transceiver hardware impairments and imperfect channel estimates, where N single-antenna sensors communicate with a single-antenna destination via a single-antenna half-duplex amplify-and-forward relay. We assume that the consideration of remote-area wireless sensor application restricts the direct communication between the sensors and destination. Specifically, we first derive the exact and asymptotic outage probability expressions under hardware impairments and imperfect channel estimates over Rayleigh fading channels.Then, we formulate and evaluate an optimization problem for source-sumpower minimization taking both the power and outage constraints into account in the presence of transceiver hardware impairments and imperfect channel estimates with the help of Karush-Kuhn-Tucker conditions. The numerical results corroborate our theoretical findings and demonstrate the optimality of the considered system. Moreover, our results reveal that (i) the system's diversity order reduces to zero because of the irreducible error floor occurs from the fixed channel estimation errors, (ii) the source-sum-power consumption reduces with the increased maximum available relay power and increases as the number of sensor nodes increases, (iii) the hardware impairments and imperfect channel estimates significantly increase the source-sum-power consumption, and (iv) the proposed source-sum power minimization scheme can optimize the performance of the considered system. Also, we compare our proposed optimal power allocation scheme with the uniform power allocation scheme, from which it is shown that the proposed scheme is better than the uniform one irrespective of the involved parameters. Furthermore, we compare our proposed scheme with some existing approaches, such as time division scheme and decode-and-forward relay scenario, in terms of outage probability and source-sum-power minimization.

Performance evaluation of multiuser Internet of Things wireless‐powered relaying networks with transceiver hardware imperfections over Nakagami‐m fading channels

“…Figures 8 and 9 depict the EC performance with respect to SNR for TS and PS schemes, respectively, when κ ¼ 0, 0:1. It can be observed from these figures that the upper bound for the EC given in (39) is in good agreement with exact analysis presented using ( 37) and ( 38) under both TS and PS schemes, especially at medium-to-high SNR. This validates the tightness of our proposed upper bound on the EC, as also shown in Table 3 for TS scheme and in Table 4 for PS scheme.…”

“…[30][31][32][33][34][35][36][37][38] have studied the performance of multiuser relay networks without taking the SWIPT architectures and transceiver hardware impairments into account. The impact of transceiver hardware impairments on the multiuser relay networks has been investigated in Kharwar et al, 39,40 but without exploiting the SWIPT benefits. However, the ever-rising demand of IoT services/ applications has emphasized the use of EH techniques for multiuser-enabled cooperative relay networks.…”

“…Recently, multiuser (or multi‐source) communications have attracted remarkable attention due to their ability of enhancing the diversity of the wireless communication systems. The performance of multiuser cooperative relay networks has been widely discussed in the related literature, 30–40 but without taking the SWIPT architecture into account. Recently, the performance of SWIPT‐aided multiuser relay networks has been analyzed in Nguyen et al, Lai et al, Xie et al, Gupta et al, and Shukla et al 41–45 and related literature.…”

“…As per the aforementioned discussion, it is evident that de Melo et al and da Costa, Yang et al, Zhang et al, Hemachandra and Beaulieu, Fan et al, Guimaraes et al, Liu et al, Lateef et al, and Lv et al 30–38 have studied the performance of multiuser relay networks without taking the SWIPT architectures and transceiver hardware impairments into account. The impact of transceiver hardware impairments on the multiuser relay networks has been investigated in Kharwar et al, 39,40 but without exploiting the SWIPT benefits. However, the ever‐rising demand of IoT services/applications has emphasized the use of EH techniques for multiuser‐enabled cooperative relay networks.…”