In this paper, the exact analytical signal-to-interference-plus-noise ratio (SINR) expressions, for the combined effects of phase noise (PHN) and carrier frequency offset (CFO), are derived for the desired user ship and eavesdropper in the novel Reconfigurable intelligent surface (RIS) aided hybrid satellite-terrestrial maritime (R-HSTM) communication system. For analysis, Walsh Hadamard (WH)-Spread Orthogonal Frequency Division Multiplexing (SOFDM) transmission scheme is employed at Low earth orbit (LEO) satellite and on-shore terrestrial base station sources to support variable bit rate (VBR) transmission at the physical (PHY) layer. These sources are equipped with multiple antennas to perform Maximal ratio transmit (MRT) beamforming towards the passive (P)-RIS. In addition, the system employs artificial noise (AN) injection at sources to further thwart eavesdropping attempts. To sum up, this paper provides a three-layer security at the PHY layer of R-HSTM communication system by employing WH-SOFDM, RIS and AN. For simulation, three-state Fontan satellite/terrestrial maritime channel models forL−band communication are considered. Based on derived SINR expressions, bit error rate (BER) has been evaluated for desired user ship and eavesdropper. Also, secrecy capacity of the proposed system has been analyzed. These performance metrics are investigated considering both perfect and imperfect channel state information (CSI) conditions. In addition, pilot-based channel estimation is performed at the receiver, and closed-form estimation error variance is evaluated for each cascaded channel link. The results illustrate a continuous deterioration in these performance metrics with increase in doppler frequency shift, PHN and channel estimation error variance. Also, average BER performance and secrecy capacity deterioration by 2.5% and 8.33% respectively is illustrated for every increase in estimation error variance by the factor of 0.2. The simulation and analytical results depict a close match. Later, stage-by-stage system computational complexity is assessed for the proposed hybrid system, in comparison to the conventional OFDM based R-HSTM communication system.

A finite blocklength (FBL) twin-user non-orthogonal cooperative downlink system is considered, wherein a base station simultaneously communicates with the users whilst relying on simultaneous wireless information and power transfer (SWIPT) enabled energy harvesting relay. Closed-form analytical expressions are obtained for the end-to-end average block error rate (BLER) assuming potentially dissimilar Nakagami-m fading links. Furthermore, asymptotic expressions are derived for the individual user's end-to-end average BLER performance and diversity order at high signal to noise ratios (SNRs). Additionally, since, the stronger user's signal is detected, while assuming the weaker user's signal to be interference, an analytical bound has been obtained for characterizing the effect of this interference on the BLER performance of both users. Furthermore, a framework is developed for joint relay splitting factor and user power allocation towards end-to-end blocklength minimization under strict reliability constraints by converting the original non-convex optimization problem to a convex geometric program (GP) that can be solved efficiently. Simulation results are presented to validate the analytical expressions derived and illustrate the efficacy of the proposed scheme.

This study analyses the performance of a non‐orthogonal multiple access‐based two‐way relaying system. Analytical expressions are obtained to characterise the outage probability and outage floor of the system for end‐to‐end communication over Rayleigh fading channels. Furthermore, results are also presented for the resulting individual user and sum ergodic capacities. A user power allocation technique is proposed for sum‐rate maximisation with user quality of service constraints by transforming the original non‐convex problem into a difference of convex program that can be readily solved. Finally, simulation results are presented to authenticate the analytical expressions obtained for the various quantities and illustrate the efficacy of the proposed scheme.

In this study, the exact closed‐form signal‐to‐interference‐noise ratio (SINR) expression, for the impact of Doppler frequency shift on minimum mean square error receiver is derived for Walsh Hadamard (WH) and polyphase carrier interferometry (CI) code based multicarrier spread orthogonal frequency division multiplexing (SOFDM) transmission scheme over integrated satellite–terrestrial broadcast system. Additionally, bit error rate and spectral efficiency are analysed based on the obtained SINR expression. To examine that, three‐state Fontan land mobile satellite, and six‐path typical urban and rural area terrestrial channel models are employed. This analysis is performed to substantiate variable bit rate (VBR) quality of service at the physical layer of digital video broadcast satellite handheld (DVB‐SH)‐A architecture, the provision of which is absent in DVB‐SH standard. VBR is assumed for SOFDM. The results illustrate that WH‐SOFDM outperforms CI‐SOFDM under both performance measures in all the three channel environments. Further, pilot‐based channel estimation technique is performed and the estimated error variance is evaluated for VBR WH/CI‐SOFDM. Later, block‐wise system computational complexity of WH/CI‐SOFDM schemes is evaluated. It is shown that, CI‐SOFDM is a relatively more complex system than WH‐SOFDM. Thus, a trade‐off is present between the achieved performance gain and system complexity.

Slow moving traffic in heavily populated cities, can many times result in loss of lives due to emergency vehicles not being able to reach their destination hospitals on time. Recent advances in the field of Intelligent Transportation Systems (ITS) makes it increasingly likely that vehicles in the near future will be equipped with advanced systems that allow inter vehicular communication. In this paper, we assume the usage of such a system to optimize the lane level dynamics for an emergency vehicle (EV), traversing a multi lane stretch of road under a variety of traffic settings. In particular, we present the Fixed Lane Strategy (FLS) and the Best Lane Strategy (BLS) for EV traversal and perform an extensive agent based analysis to study their strengths and weaknesses. Through a series of experiments performed using the well-known traffic simulator SUMO, we could show that: (a) BLS performs better than SUMO strategy on all traffic settings we tested. (b) BLS performs better than FLS in settings that capture real-world traffic conditions involving congestion and uncertainties while FLS performs better in well-behaved conditions and (c) BLS was found to be the best strategy for the setting calibrated using real world data (obtained from NYCDOT).