In this paper, we consider a novel cooperative underlay cognitive radio network based on non-orthogonal multiple access (CR-NOMA) with adaptive relay selection and power allocation. secondary networks, dedicated assistance user are used to achieve communication between the base station far (and near) user. Here, two-stage allocation strategy is proposed maximize achievable data rate of while ensuring service quality near Furthermore, closed-form expressions outage probability two users...

In many practical communication environments, the presence of uncertain and hard-to-estimate noise poses significant challenges to cognitive radio spectrum sensing systems, especially when distribution deviates from Gaussian distribution. This paper introduces a cutting-edge multi-antenna methodology that synergistically integrates complete ensemble empirical mode decomposition with adaptive (CEEMDAN), wavelet packet analysis, differential entropy. Signal feature extraction commences by...

The high-speed movement of vehicles is the core factor affecting rapid development vehicular ad hoc network (VANET), especially impact vehicle mobility on data access and transmission performance. However, classic IEEE802.11p protocol are still used in multi-hop VANET under highway system, which adopted low-speed environment. Therefore, performance existing analyzed theoretically, it found that will be greatly reduced with increase speed. In order to improve environment, an improved...

The complexity of the channel condition in Internet vehicles (IoV) may increase bit error rate (BER) intelligent vehicle terminals, resulting data transmission failures or errors. Therefore, it is necessary to improve performance communication protocols under error-prone conditions. This article investigates influence access categories’ (ACs) with errors by using four <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi mathvariant="normal">A</a:mi>...

In order to meet the demand for large-scale device access in Narrowband Internet of Things (NB-IoT) and overcome problem that some resources are wasted due use single decode-and-forward (DF) or amplify-and-forward (AF) collaboration traditional collaborative communication, this paper introduces a non-orthogonal multiple (NOMA) orthogonal (OMA) hybrid method into NB-IoT proposes new Hybrid NOMA transmission protocol with relay adaptively selectable collaboration, which is represented as an...

Abstract The authors study the energy efficiency (EE) of ambient backscatter communication (AmBC) device‐assisted and reconfigurable intelligent surfaces (RIS)‐assisted non‐orthogonal multiple access (NOMA) downlinks. establish two optimisation problems based on collaborative devices (AmBC devices, RIS) with objective maximising EE system, taking into account requirements power limitation rate limitation, etc. also obtain solutions by optimising relevant performance metrics alternating...

To solve the conflict when multi-user packets are transmitted in a shared wireless link, novel frameless slotted-ALOHA protocol is proposed. Signature codes used to help receiver identify set of transmitting users, and successive interference cancellation technology employed recover conflicting packets. Thus, information slot can be reused reduce number retransmissions. Taking backlogged users each as system state, Markov chain model established analyze protocol, which state transition...

This paper proposes a multifrequency seamless dual-link handover scheme based on beamforming for the high-speed railway (HSR) communication, i.e., when train travels to edge of overlapping area adjacent two cells, gain beam is assigned by target base station (BS) using technique cover entire region enhance received signal strength (RSS) and opportunity. The switching antenna allowed multiple times improve traditional reduce failure probability (HFP) greatly. In process reception, considering...

To alleviate the contradiction between supply and demand of spectrum resources in large-scale 5G network environment, we propose minimum remaining idle time channel selection scheme under imperfect sensing (MRIC-IS) combination with actual cognitive radio ad hoc networks (CRAHNs) environment. In this scheme, secondary users (SU s) select available catches errors form misdetection false alarm. By analyzing resource flow process primary (PUs) SUs effect on process, build a two-layer 2-D...

In this paper, we consider a communication scenario where non-orthogonal multiple access (NOMA)-based cooperative direct and relay transmission (CDRT) coexists with an underlay cognitive radio network. The decoding results of near user U1 in the secondary network (SN) are divided into success or failure, their strategies formulated, respectively. For primary (PN), define derive outage probabilities receiver PD two slots. SN, (in case 1 2) slots U2 second slot. Finally, exact closed-form...