Citation: Chatzoulis, D.; Chaikalis, C.; Kosmanos, D.; Anagnostou, K.E.; Xenakis, A. 3GPP 5G V2X Error Correction Coding for Various Propagation Environments: A QoS Approach. Electronics 2023, 12, 2898. https://doi.org/10.3390/ electronics12132898 Academic Editor: Dimitris Kanellopoulos Received: 3 June 2023 Revised: 22 June 2023 Accepted: 29 June 2023 Published: 1 July 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). electronics Article 3GPP 5G V2X Error Correction Coding for Various Propagation Environments: A QoS Approach Dimitrios Chatzoulis 1, * , Costas Chaikalis 1 , Dimitrios Kosmanos 1,2 , Kostas E. Anagnostou 3 and Apostolos Xenakis 1 1 Department of Digital Systems, School of Technology, University of Thessaly, Geopolis Campus, 41500 Larissa, Greece; kchaikalis@uth.gr (C.C.); dikosman@uth.gr (D.K.); axenakis@uth.gr (A.X.) 2 Department of Electrical & Computer Engineering, University of Thessaly, 38221 Volos, Greece 3 Department of Informatics & Telecommunications, University of Thessaly, 35100 Lamia, Greece; anagko@uth.gr * Correspondence: dchatzoulis@uth.gr Abstract: Vehicle-to-everything (V2X) communications is an emerging branch of wireless communi- cations and has recently gained a lot of interest not only from academia but also from the automotive and telecommunications industry. An important feature of V2X telecommunication systems is that the communication quality varies quickly in time due to the high mobility of the transceivers and due to the rapid change in the fading characteristics of the communication medium. For this reason, it is vital to maintain tolerable quality of service (QoS) in a V2X communication environment, in terms of communication reliability, power, end-to-end latency, data rate, communication range, throughput and vehicle density. A significant impact on the quality parameters of the system has been the coding scheme used by the V2X telecommunication system. For this purpose, we examine the effect that popular coding schemes have on the QoS of a V2X communication system. More specifically, the impact of fourth-generation long-term evolution (4G-LTE) turbo codes, fifth-generation new radio (5G-NR) polar codes and 5G-NR low-density parity-check codes (LDPC) on the QoS parameters of a V2X communication system is researched. To this end, we employ stochastic V2X propagation models that simulate every possible V2X channel state and traffic environment, based on the third-generation partnership project (3GPP) Release 16 specifications. These propagation models form the basis of our study, since through them, at a first level, we analyze the frame error rate (FER) performance for different levels of signal-to-noise ratios (SNRs) for all the aforementioned coding schemes and 128-bit V2X-compatible data frames, and, at a second level, we investigate the impact of these propagation models and coding schemes on the V2X QoS parameters. Our analysis shows that turbo-based coding schemes satisfy all the QoS parameters and achieve overall communication quality comparable to polar and better than LDPC, making them suitable for small-frame 5G V2X services. Keywords: 5G-NR; 4G-LTE; V2X; turbo codes; LDPC; polar codes; stochastic V2X model; system simulation scenarios; QoS simulation scenarios; power; reliability; latency; throughput; vehicle density; data rate; communication range 1. Introduction and Literature Review Intelligent transportation systems (ITSs) are advanced solutions for providing traffic safety and sustainability, including infrastructure, vehicles, users, traffic and mobility man- agement, as well as interfaces with other modes of transport [1]. The key enablers of ITSs are V2X communications, which include vehicle-to-vehicle (V2V), vehicle-to-network (V2N) or vehicle-to-infrastructure (V2I), vehicle-to-roadside units (V2R) and vehicle-to-pedestrian (V2P) communications [2]. ITSs were introduced in 1999 by the US Federal Communication Commission, and they resulted in great research work in the USA [3] and Europe [4], which resulted in the first standards for V2X in the USA [5] and in Europe [6], respectively. Briefly, Electronics 2023, 12, 2898. https://doi.org/10.3390/electronics12132898 https://www.mdpi.com/journal/electronics