Rate Maximization in Vehicular uRLLC with Optical Camera Communications

Optical camera communication (OCC) has emerged as a key enabling technology for the seamless operation of future autonomous vehicles. By leveraging the supreme performance of OCC, we can meet the stringent requirements of ultra-reliable and low-latency communication (uRLLC) in vehicular OCC. In this paper, we introduce a rate optimization approach in vehicular OCC through optimal power allocation while respecting uRLLC requirements. We first formulate a discrete-rate optimization problem as a mixed-integer programming (MIP) subject to average transmit power and uRLLC constraints for a given set of modulation schemes. To reduce the complexity in solving the MIP problem, we convert the discrete-rate problem into a continuous-rate optimization scheme. Then, we present an algorithm based on Lagrangian relaxation and Bisection method to solve the optimization problem. Considering the proposed algorithm, we drive the rate optimization and power allocation scheme for both discrete-rate and continuous-rate optimization schemes while satisfying uRLLC constraints. We first analyze the performance of the proposed system model through simulations. We then investigate the impact of proposed power allocation and rate optimization schemes on average rate and latency for different target bit error rates. The results show that increasing the transmit power allocation improves the average rate and latency performance.Comment: 30 Pages, 13 Figure

Design and Testing of a Transmitter-Channel-Receiver Model Using Matlab 5G Toolset

Make possible new incoming services and enhance the current ones in order to improve our lives, is the common objective of the engineers. In this way, for improving our communications, we have passed through four generations, each of them with its corresponding enhancements. However, the fourth generation has some limitations that must be solved to keep evolving our communications. Hence, the fifth generation (5G) is forecast to be launched in 2020. This thesis is based on 5G and it has approached three different objectives by using Matlab 5G Toolset. First, the study of 5G waveforms has been carried out. These waveforms are W-OFDM, F-OFDM and CP-OFDM and their spectrums have been compared for different bandwidths and subcarrier spacings. Then, a basic transmitter-channel-receiver chain model has been designed and tested in terms of bit error rate. Finally, a new configuration for improving the reliability of 5G communi-cations, based on 3GPP, has been designed and proved. This configuration includes some vari-ations related with the spatial diversity, the HARQ protocol and the code rate. The analysis of the results has shown that F-OFDM and W-OFDM achieve better spectral efficiency than CP-OFDM. However, W-OFDM presents more out of band emissions. Thus, F-OFDM with a small value of subcarrier spacing presents better performance than CP-OFDM and W-OFDM in terms of spectral efficiency and out of band emissions. In addition, during the testing of the designed model, CP-OFDM has demonstrated better bit error rate than F-OFDM and W-OFDM. Nevertheless, F-OFDM and CP-OFDM present very similar results. In addition, the new 5G configuration proposed was applied into the transmitter-channel-receiver model commented before for CP-OFDM. The new result was compared with the previous one in terms of bit error rate. Finally, this comparation shows that better bit error rate values are achieved with this new configuration. Thus, the reliability of the communications is improved

Ultra-Reliable and Low-Latency Vehicular Communication using Optical Camera Communications

Optical camera communication (OCC) has emerged as a key enabling technology for the seamless operation of future autonomous vehicles. By leveraging the supreme performance, OCC has become a promising solution to meet the stringent requirements of vehicular communication to support ultra-reliable and low-latency communication (uRLLC). In this paper, we introduce a novel approach of capacity maximization in vehicular OCC through the optimization of capacity, power allocation, and adaptive modulation schemes while guaranteeing reliability and latency requirements. First, we formulate a vehicular OCC model to analyze the performance in terms of bit-error-rate (BER), achievable spectral efficiency, and observed latency. We thus characterize reliability over satisfying a target BER, while latency is determined by considering transmission latency. Then, a capacity maximization problem is formulated subject to transmit power and uRLLC constraints. Finally, utilizing the Lagrange formulation and water-filling algorithm, an optimization scheme is proposed to find the adaptive solution. To demonstrate the robustness of the proposed optimization scheme, we translate the continuous problem into a discrete problem. We justify our proposed model and optimization formulation through numerous simulations by comparing capacity, latency, and transmit power. Simulation results show virtually no loss of performance through discretization of the problem while ensuring uRLLC requirements

Coverage and Rate of Downlink Sequence Transmissions with Reliability Guarantees

Real-time distributed control is a promising application of 5G in which communication links should satisfy certain reliability guarantees. In this letter, we derive closed-form maximum average rate when a device (e.g. industrial machine) downloads a sequence of n operational commands through cellular connection, while guaranteeing a certain signal-to-interference ratio (SIR) coverage for all n messages. The result is based on novel closed-form n-successive SIR coverage bounds. The proposed bounds provide simple approximations that are increasingly accurate in the high reliability region.Comment: 4 pages, 3 figures, submitted to IEEE Wireless Communications Letter