Ergodic Capacity Research Articles

Static and dynamic power splitting protocol enabled in DF energy harvesting Half-Duplex relaying network: Ergodic capacity analysis

In this research, we propose and examine the DF Energy Harvesting Half-Duplex Relaying Network. For this system model, the DF Energy Harvesting Half-Duplex Relaying Network is analyzed in two cases: Static and Dynamic Power Splitting Protocol. The Ergodic Capacity (EC) is introduced and derived in relation to all the primary system parameters in order to evaluate system performance. The Monte Carlo simulation results demonstrate that the mathematical and simulation are in agreement, thereby confirming the accuracy of the analytical description.

STAR-RIS-NOMA empowered vehicle-to-vehicle communications: Outage and ergodic capacity analysis

This paper delves into the performance evaluation of a non-orthogonal multiple access (NOMA) enabled vehicle-to-vehicle (V2V) communication system empowered by simultaneously transmitting and reflecting reconfigurable intelligent surfaces (STAR-RIS). Herein, we consider that a moving access point (AP) transmits superimposed signals to nearby and distant NOMA vehicles simultaneously via reflection and transmission through a STAR-RIS equipped vehicle with 2N reconfigurable elements, respectively. Specifically, by characterizing all V2V channels as double-Rayleigh fading distributed, we derive the outage probability (OP) and ergodic capacity (EC) expressions for each NOMA vehicle, by employing both perfect and imperfect successive interference cancellation (SIC) at nearby vehicle user. Furthermore, we present the asymptotic OP behavior at high signal-to-noise ratio (SNR) regime to gain deeper insights into the diversity order of NOMA vehicles. The findings reveal that the nearby vehicle under perfect SIC and far vehicle experience a diversity order of Nπ4256−π2, which is the function of number of reconfigurable elements (N) in the STAR-RIS. Whereas, a zero diversity order is obtained for nearby user under imperfect SIC case. Moreover, we analytically discuss the high SNR slopes of EC for both user vehicles. Furthermore, Monte-Carlo simulations are conducted to validate our analytical results under various channel and system parameter configurations. We also provide a comparison between the proposed scheme and STAR-RIS based orthogonal multiple access and cooperative relaying systems.

Ergodic capacity analysis of distributed RIS wireless communication system: How many RIS elements are required to beat direct LoS path?

Ergodic capacity analysis of distributed RIS wireless communication system: How many RIS elements are required to beat direct LoS path?

UAV aided NOMA relaying with energy harvesting architecture: Performance analysis

In this work, we consider a dual hop Non Orthogonal Miltiple Access (NOMA) based communication network between Source S and two destination users UA , UB which is aided by an Unmanned Aerial Vehicle (UAV) relay R. The energy constrained UAV relay harvests energy from signal transmitted by the source through Power Splitting (PS) and further transmits the signal using Amplify and Forward (AF) protocol to the destination users through NOMA. For the proposed network, we derive analytical expressions for outage probability and ergodic capacity. The impact of parameters like PS ratio and UAV altitude is studied on the overall system performance. Further, the performance of the proposed system is also compared with Orthogonal Multiple Access (OMA) scheme. The results obtained show that the energy harvesting capacity of UAV is significantly affected under Linear and Non Linear EH models. The numerical analysis done is verified through Monte Carlo Simulations.

Capacity analysis over fractional order Rayleigh fading channel under additive white generalized Gaussian noise

AbstractThis study presents an innovative fractional order Rayleigh fading model that can be used for channel capacity estimation in the presence of additive white generalized Gaussian noise. The proposed model assumes that the real and imaginary parts of channel gains are generalized Gaussian random variables, which makes it possible to consider the traditional Rayleigh fading model as a special case of fractional order Rayleigh fading. Compared to the Rayleigh model, the fractional order Rayleigh fading model offers a more precise representation of new real‐world communication, such as integrating terrestrial and underwater networks in sixth‐generation communications channels. The probability density function of the channel gain with additive white generalized Gaussian noise is analyzed here. Furthermore, the ergodic and outage capacities of the channel are determined, taking into account the assumption that the channel state information is only available at the receiver. The ergodic capacity is calculated using Meijer's G‐functions, resulting in a closed‐form expression. Numerical simulations demonstrate the superiority of the fractional order Rayleigh fading model over the Rayleigh channel. Moreover, the impact of ergodic and outage capacities under diverse channel characteristics is assessed.

Capacity Optimization for RSMA-Based Multi-User System over Underwater Turbulence Channel

The underwater environment used for communication is harsh and complex, necessitating heightened standards for spectral efficiency and reliability in underwater wireless optical communication (UWOC) systems. The focus of this work is on the performance of multi-user UWOC systems operating in oblique channels of ocean turbulence downlink, where users are randomly distributed at a certain depth. A joint optimization scheme is proposed, which joints rate-splitting multiple access (RSMA) and power allocation so that the system’s ergodic sum capacity is optimized to improve the transmission bandwidth. Furthermore, the probability density function (PDF) and cumulative distribution function (CDF) models for the received signal-to-noise ratio (SNR) of a multi-user multiple-input multiple-output (MIMO) system operating in the turbulent underwater oblique channels are established, accounting for the avalanche photodiode (APD) shot noise and solar radiation noise. Theoretical derivations are presented to quantify the ergodic capacity and outage probability of the multi-user system utilizing the RSMA technology. Subsequently, a numerical analysis is conducted to investigate the influence of the power allocation coefficient, RSMA, and the joint optimization algorithm on the performance of a two-user MIMO system leveraging RSMA. The simulation results show that our optimization scheme effectively reduces the outage probability, thereby achieving the maximum system sum rate and validating the practical feasibility and efficacy of the proposed scheme.

Modeling and performance analysis of moving V2V 5G NR systems

Vehicle-to-vehicle (V2V) communication is a promising solution for enhancing network performance. This paper presents the modeling and performance analysis of moving V2V fifth generation new radio (5G NR) systems using Poisson point process (PPP) and Matern cluster process (MCP). A new mode selection scheme, the hybrid communication scheme (HCS), is proposed to improve V2V 5G NR system performance. The HCS employs side link (SL) communications, a predefined average threshold of SL received signal strength (RSS), and a minimum residence time for V2V mode. We derive expressions for the threshold RSS, minimum residence time, and ergodic capacity to evaluate HCS performance. Monte Carlo simulations using Matlab confirm the analytical results and demonstrate the advantages of the proposed scheme over related approaches in the literature.

Resource allocation for device-to-device communications underlaying uplink cellular networks

Underlying cellular networks, device-to-device (D2D) communications are a practical network technology that can increase power efficiency and spectrum usage for close-proximity wireless services and applications. However, D2D link interference, when sharing resources with cellular users (CUs), poses a major challenge in such distribution situations. In this research, we primarily utilize wireless channel data that exhibits slowly shifting large-scale fading to conduct spectrum sharing and power allocation. The overall ergodic capacity of all cellular user equipment (CUE) links is initially considered as the optimization target in order to maximize the overall throughput of CUE links while ensuring the reliability of each D2D link. Then, the expansion of the minimum ergodic capacity is measured to ensure a more consistent capacity performance across all CUE links. We utilized algorithms that are resilient to channel fluctuations and produce optimal resource allocation. We use MATLAB, and the computer simulation validates its intended performance.

Intelligent reflecting surface‐aided D2D‐enabled coordinated multipoint NOMA systems over Nakagami‐m fading channels

SummaryThe future wireless communication networks (beyond 5G) are intended to provide seamless connectivity, higher data rates, and lower latency. The intelligent reflecting surface (IRS) promises extended network coverage. The non‐orthogonal multiple access (NOMA) technique provides higher spectral efficiency and supports a larger number of users. In general, the cell‐edge users far from the base station are affected by severe fading, which may result in an outage. To overcome this issue, we propose an IRS‐aided device‐to‐device (D2D)‐enabled two cells coordinated NOMA system in which a common cell‐edge user acts as D2D receiver. The cell‐edge user receives the signals from near users, IRSs, and both base stations to achieve better diversity. We analyze the outage probability of cell‐edge user, while all the fading channels are assumed Nakagami‐ and obtain a closed‐form expression at higher signal‐to‐noise ratios. We develop an algorithm to find the ergodic capacity of the cell‐edge user. We validate the mathematical expressions with simulation results and see a substantial improvement in outage performance over the existing systems.

Spectrum Sharing Environment Using Deep Learning Techniques

Recently, the satellite communication has main demand but still facing main problems which are the spectrum limited, both cognitive-radio (CR) and non-orthogonal-multiple-access (NOMA) methods are identified as a one of the potential solutions for these issues. Using the deep learning techniques with the CR and NOMA systems will be improvement in the spectrum effectiveness. One of the performance enhancements of the NOMA, the integration with the satellite-terrestrial-relay-network (ISTRN) in a spectrum-sharing context of several main-users (PUs) is examined. We specifically presented and given the interference limitation imposed by several nearby pus and its effect on each other’s. The closed-form formulations are investigated the ergodic-capacity (EC) and outage-probability (OP). The asymptotic- analysis for OP at high SNRs is achieved to get additional insights. To support our research and reveal the effects of the significant characteristics on the quality of the system; the numerical data and analysis are provided with deep discussions.

Ergodic analysis of IRS-NOMA with inter-cell interference and Imperfect-CSI and SIC over Nakagami-m faded channel

Future wireless technology requires higher data rates, low latency, and flexibility to provide services to users. To fulfil these demands, various multiple access techniques are proposed. Among these techniques, the non-orthogonal multiple access technique (NOMA) is providing better features compared to orthogonal multiple access (OMA) techniques, such as more number of radio resources with low latency. In NOMA based communication system, if a user is lying on the cell's edge, their performance is poor. Recently, intelligent reflecting surfaces (IRS)-NOMA system is introduced to enhance its performance. To implement IRS-NOMA in a real-time scenario, the impact of inter-cell interference and imperfect-channel state information (CSI) and successive interference cancellation (SIC) is very much required. In this work, we derived analytical expressions to evaluate the Ergodic capacity of the IRS-NOMA over the Nakagami-m faded channel by considering inter-cell interference, imperfect-CSI, and SIC. By considering these factors, this work offers a comprehensive understanding of the system's capabilities and limitations. Here, two user IRS-NOMA is considered and also evaluated the analytical results by varying fading parameter (m), number of interferers (K), error in CSI and SIC, and IRS elements. These results are also supported by simulated results.

Performance analysis of fixed gain relay-assisted vertical UWOC systems with generalized misalignment fading model

Underwater wireless optical communication (UWOC) as a potential underwater transmission technology has attracted increasing attention due to its high speed, low delay, and wide range of applications. In addition to absorption and scattering, ocean turbulence fading and misalignment fading seriously affect system performance. Thus, the relay assistance methods have been presented as an effective technique for fading mitigation in optical channels. In this paper, we propose a fixed gain amplify-and-forward (AF) relay-assisted vertical UWOC system with a generalized misalignment fading model over multi-layer cascaded gamma-gamma turbulence channels. For the relay-assisted system, the cumulative distribution function (CDF) and the probability density function (PDF) of the end-to-end instantaneous signal-to-noise ratio (SNR) are derived with the help of the Meijer-G function and the bivariate Fox-H function. Subsequently, based on these statistical analyses of SNR, we derive the closed-form expressions of the outage probability and ergodic capacity. Furthermore, we provide a very tight asymptotic expression for the outage probability in terms of simple functions under high SNR, and the diversity order is analyzed. Finally, results from Monte Carlo simulations are used to validate our derived results. Numerical results for different relay position deployments and alignment error levels reveal that the relay-assisted vertical UWOC system performs better when the relay node is located near the source, while the increase of alignment error level can damage the system performance.

On the transmission performance of DS-CDMA-based drone swarm

In drone swarm communication, multi-user interference can occur in the transmission within the drone swarm due to the randomness of the drone positions. This article mainly investigates the transmission performance of drone swarm communication, including outage probability and ergodic capacity, using direct sequence code division multiple access (DS-CDMA). In this work, the randomness of the drone position distribution is modeled using random geometry theory. Specifically, the author uses wireless communication modeling and stochastic geometry theories to establish a signal model using DS-CDMA technology. Next, closed-form analytical expressions for outage probability and asymptotic analysis are derived. Based on this, the influence of system factors such as DS-CDMA parameters and transmission distance on the transmission performance is summarized, and numerical results are provided to investigate the effect of the randomness of drone position distribution on the transmission performance between target communication nodes. In addition, the comparison between theoretical numerical results and Monte Carlo simulation results also verifies the correctness of the transmission performance analysis model proposed in this paper.

Capacity Analysis of Hybrid Satellite-Terrestrial Systems with Selection Relaying.

A hybrid satellite-terrestrial relay network is a simple and flexible solution that can be used to improve the performance of land mobile satellite systems, where the communication links between satellite and mobile terrestrial users can be unstable due to the multipath effect, obstacles, as well as the additional atmospheric losses. Motivated by these facts, in this paper, we analyze a system where the satellite-terrestrial links undergo shadowed Rice fading, and, following this, terrestrial relay applies the selection relaying protocol and forwards the information to the final destination using the communication link subjected to Nakagami-m fading. For the considered relaying protocol, we derive the exact closed-form expressions for the outage probability, outage capacity, and ergodic capacity, presented in polynomial-exponential form for the integer-valued fading parameters. The presented numerical results illustrate the usefulness of the selection relaying for various propagation scenarios and system geometry parameters. The obtained analytical results are corroborated by an independent simulation method, based on the originally developed fading simulator.

Coverage Probability and Ergodic Capacity of Cell-Free Massive MIMO System

Coverage Probability and Ergodic Capacity of Cell-Free Massive MIMO System

UAV swarm communication reliability based on a comprehensive SINR model

Communication reliability is one of the most important factors in ensuring the safe operation of unmanned aerial vehicles (UAVs). The reliability of wireless communication for a UAV swarm is typically characterized by the signal-to-interference-and-noise ratio (SINR). However, previous work on UAV swarm communication reliability did not use a comprehensive SINR model. In this paper, we derived two novel closed-form approximations – lognormal and generalized beta prime (GBP) - of UAV swarm communication reliability based on a comprehensive SINR model. The model includes shadowing, multipath fading, the dependence of fading on external factors, which are the probability of line-of-sight (LoS) and the physical environment, as well as all possible interference within the system, which may be from the UAVs and the ground control station (GCS). For typical swarm heights between 60 – 300 m and up to 32 UAVs, comparisons of the approximate and simulated reliabilities for UAV swarms with a radius up to a critical value (which increases with the number and transmit power of the UAVs) show that only the lognormal approximation is accurate for all uplink and downlink communications, up to a critical horizontal distance from the GCS (which increases with height). Benchmarking of the lognormal approximation shows that neglecting either shadowing or multipath fading leads to high approximation errors. An example of how the lognormal approximation can be used to evaluate and maintain the communication reliability of a UAV swarm during deployment is given. Furthermore, it can be used to derive other SINR-dependent performance metrics, such as ergodic capacity and symbol error rate, which are useful in UAV network design and monitoring.

On performance analysis of non-orthogonal multiple access downlink for cellular-connected unmanned aerial vehicle relaying assisted vehicle-to-everything system

This paper presents the unmanned aerial vehicle (UAV) relays’ assisted vehicle-to-everything (V2X) network to implement the internet of things (IoT) systems with improvement in the coverage area. Such a network benefits from many advantages of the non-orthogonal multiple access (NOMA) scheme. We have implemented a decode-and-forward (DF) scheme for these UAVs. Then, we characterize the channels as Nakagami-m fading to evaluate the performance of the system. We derive closed-form expressions of outage probability (OP), ergodic capacity (EC), and throughput. The results show that the performance of the system depends on the transmitted signal-to-noise ratio (SNR) at the base station and the heights of the UAV relays. Target rate and power allocation factors are two main parameters that can be adjusted to achieve better performance. The results also compare to the system without UAV and OMA technique that shows the advantages of deploying UAV-assisted NOMA. Therefore, the design of NOMA for UAV relay-assisted V2X systems provides sufficient demand. The simulation results verified the effectiveness of the proposed UAV network and the precision of the theoretical analysis.

On The Effective Capacity Performance Analysis Over Nakagami‐m Distribution‐Based Double‐Shadowed Rician Fading Channel

AbstractThe practical applications within the domain of the fifth generation (5G) and the emerging beyond 5G network necessitate a high data transmission rate along with minimal achievable delay. With this objective in focus, the maximum capacity is extensively quantified through the utilization of the delay‐constrained effective capacity (EC) technique, which stands in contrast to Shannon's ergodic capacity. The current study is engaged in the analysis of EC within a delay‐limited wireless system operating in a double‐shadowed Rician (DSR) fading channel. Within this channel, only the Nakagami‐m distribution concept has been applied to both the dominant and secondary shadowing components of the proposed network model. A new exact closed‐form expression for EC within the DSR fading channel has been derived using the Fox‐H function. Furthermore, an analysis has been conducted for both high and low signal‐to‐noise ratios to provide further insights and explanations for the proposed model. It is worth noting that the results obtained from both simulation and analytical methods exhibit substantial similarity, revealing interdependence among various parameters present in the proposed model.

Multiple HAPS-based space-air-ground network with FSO communication: a performance analysis.

Due to the fact that the existing generation of wireless communication cannot possibly keep up with the current traffic explosion and emerging applications, research and development on next-generation (i.e.,sixth generation, 6G) wireless technologies is being carried out worldwide. In this regard, it is anticipated that the space-air-ground (SAG) network with free space optics (FSO) communication can provide the terabits per second throughput necessary to sustain various potential 6G applications. However, FSO communications are susceptible to atmospheric turbulence, pointing errors, and beam scintillation effects. To remedy the severe atmospheric effects, we propose a multiple high-altitude platform station (HAPS)-based SAG network with a HAPS selection scheme. For the proposed system, we have derived the closed-form expressions for outage probability, average symbol error rate (SER), ergodic capacity, and outage capacity over Málaga distribution with pointing errors. Further, the asymptotic expressions for outage probability, average SER, and outage capacity were derived to enhance the comprehension of the system from a practical standpoint. It is observed from the numerical results that the multiple HAPS-based FSO system performs better than the existing HAPS-based FSO systems.

Analysis of Carrier Aggregation as a Diversity Technique for Improved Spectral Efficiency and Secrecy Performance in Mobile Communications

Carrier aggregation (CA) was introduced in mobile communication systems in response to the demand for higher network capacity. CA was conceived as a technique to achieve higher data rates by aggregating multiple blocks of spectrum from the same or different frequency bands. This work explores a different point of view, where CA is employed not as a way to increase capacity through using more bandwidth, but as a diversity technique in order to increase the spectral efficiency of the existing spectrum, and therefore, achieve higher capacity without needing additional spectrum. A mathematical model and set of closed-form expressions are provided, which can be used to characterise the performance of CA as a diversity technique (in terms of both ergodic capacity and secrecy capacity) and determine the impact of various relevant configuration parameters. The numerical results obtained by evaluating the mathematical expressions derived in this work are in line with our previous simulation studies and demonstrate that CA can be effectively exploited as a diversity technique to improve the capacity and performance of mobile communication systems compared to the case of single-carrier transmission over the same amount of bandwidth.