Outage probability of MIMO cognitive radio networks with energy harvesting and adaptive transmit power

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Outage probability of MIMO cognitive radio networks with energy harvesting and adaptive transmit power Nadhir Ben Halima1

ˆ 2 · Hatem Boujemaa

Received: 1 February 2020 / Accepted: 9 October 2020 © Institut Mines- and Springer Nature Switzerland AG 2020

Abstract This paper derives the outage probability of cognitive radio networks (CRNs) with energy harvesting (EH). The primary nodes have a single antenna, whereas the secondary nodes have multiple antennas. A secondary source S harvests energy from radiofrequency (RF) signal received from primary transmitter PT using nr,S antennas. S also adapts its power so that the interference at primary receiver PR is less than threshold I . The main contribution of the paper is to derive the throughput of multiple input multiple output (MIMO) CRN with RF energy harvesting and adaptive transmit power. We also optimize the secondary throughput by choosing the optimal harvesting duration. Keywords CRN · MIMO · Outage probability · Throughput maximization

1 Introduction In cognitive radio networks (CRNs), primary and secondary nodes share the same spectrum using interweave, underlay, or overlay techniques [1–5]. In interweave CRN, the secondary nodes transmit when the primary nodes are idle. Spectrum sensing algorithms such as an energy detector or matched filter are used to detect vacant frequency bands. In underlay CRN, secondary nodes adapt their power in order not to disturb the primary nodes. In the overlay CRN, the secondary and primary nodes transmit at the same time and over the same bandwidth the secondary nodes dedicate a part of their power to relaying primary signals. In conventional wireless systems, each node has its own battery. Recently, the concept of energy harvesting (EH) has been suggested where solar energy, wind, or RF signals are used to recharge the batteries of different nodes [6–8]. When energy harvesting is employed, the source is equipped

 Nadhir Ben Halima

with a rechargeable EH battery that harvests energy from the received RF signal or uses solar energy. Therefore, the source’s battery should not be recharged or changed. Cooperative communication for energy harvesting systems has been suggested in [9–13] using different relaying techniques. EH has also been extended to two-way relaying systems [14, 15]. In two-way relaying, communication is performed from node A to node B and from node B to node A at the same time using a relay. Each node receives its own signal and that of the other node. Each node suppresses the self-interference before decoding the signal of the other node [14, 15]. Optimal power allocation with optimal relay selection for EH systems was suggested in [16–18]. EH for CRN has been studied in [19–21]. The detection probability of a CRN with switch and stay combining was derived in [22]. The bit error probability of a CRN with a nonlinear energy harvesting model was given in [23]. A fixed transmit power was studied in [19–21]. Additionally, the harvesting duration was not optimized in [19–21]. Our contributions are as follows: