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Enhanced autonomous resource selection for LTE-based V2V communication
... While the algorithm specified by 3GPP [18], [19] is addressed in [10], the others focus on new approaches. In both [11] and [12], resources are grouped into sub-pools that are associated with vehicles based on their direction and/or position on the road, thus reducing the risk of collisions due to allocations performed by terminals hidden to each other (mainly because of the distance in the highway scenarios and of the buildings in the urban areas). In [13], the adoption of maps of the resources sent within the CAMs is proposed. ...
... The main aspects of the cited papers dealing with resource [11] Before Release 14 Autonomous, based on positions Not specified simulator Random allocation Kim et al. [12] Before Release 14 Autonomous, based on positions Not specified simulator Random allocation Cecchini et al. [13] Beyond Release 14 Autonomous, with observed occupations piggybacked in data packets ...
... From (37), we can also write the corresponding CDF as 11 (a) Example of case 1. ...
Short-range wireless technologies will enable vehicles to communicate and coordinate their actions, thus improving people's safety and traffic efficiency. Whereas IEEE 802.11p (and related standards) had been the only practical solution for years, in 2016 a new option was introduced with Release 14 of long term evolution (LTE), which includes new features to enable direct vehicle-to-vehicle (V2V) communications. LTE-V2V promises a more efficient use of the channel compared to IEEE 802.11p thanks to an improved PHY layer and the use of orthogonal resources at the MAC layer. In LTE-V2V, a key role is played by the resource allocation algorithm and increasing efforts are being made to design new solutions to optimize the spatial reuse.In this context, an important aspect still little studied, is therefore that of identifying references that allow: 1) to have a perception of the space in which the resource allocation algorithms move; and 2) to verify the performance of new proposals. In this work, we focus on a highway scenario and identify two algorithms to be used as a minimum and maximum reference in terms of the packet reception probability (PRP). The PRP is derived as a function of various parameters that describe the scenario and settings, from the application to the physical layer. Results, obtained both in a simplified Poisson point process scenario and with realistic traffic traces, show that the PRP varies considerably with different algorithms and that there is room for the improvement of current solutions.
... -The transmitting vehicle can decode the SCI (control information) transmitted by other vehicles within a sensing range (r sense ) and thus knows which time-frequency resources are allocated for the other vehicles [65,127]. ...
... -Continuously monitor all the available radio resources except its own. Specifically, it needs to measure the received power on each time-frequency resource to predict the interference level for each time-frequency resource within the resource pool [65,127]. ...
... In this thesis, to determine whether or not an SCI from another vehicle can be decoded, assumptions based on reception power are used. If the reception power is larger than some predefined threshold, the SCI is deemed to be decodable [65]. However, different assumptions based on distance or radio proximity can also be used. ...
Recent research shows that Vehicle to Everything (V2X) communication based on LTE
can provide enhanced safety, efficient traffic management and support a wide range of
infotainment applications. The safety features enable a high reduction in casualties and
improve the fuel/time efficiency of commuting by exchanging and sharing the information between the vehicles. Infotainment applications include on-board Internet access, media downloading, localised map updates, e-commerce and location-aware services. This thesis presents a novel cross layer design to improve the reliability, throughput and lower the latency at high vehicle speeds for video and safety broadcast in an LTE-A system.
A comprehensive analysis of the LTE-A Physical layer performance for different vehicle
speeds, environments, Modulation and Coding Schemes (MCS) and multiple antenna techniques is investigated. Multipath components in the elevation and azimuth dimension are considered using a 3D extension of the standardised 2D ITU-R channel model combined with measured 3D antenna patterns. The consideration of a 3D channel model implied larger angular spreads and lower spatial correlation values with a 7Mbps throughput gain as compared to the 2D ITU channel. Performance results on the impact of BS antenna array spacing and arrangement recommend a vertical or the 2D planar (square type) arrangement.
A Cellular Infrastructure to Vehicle (I2V) system is proposed for transmitting high data rate video broadcast over MIMO channels with optimised cross-layer parameters under different channel conditions. Results show an improvement of up to 5dB SNR in highly correlated channels and the use of higher MCS modes in good channel conditions. The reliability of the video broadcast is further improved by combing packets from vehicle antenna and passenger wireless devices called user cooperation to improve diversity. Bit level simulations show that the outage could be improved from 42% to 10% with a mean throughput gain of 31Mbps due to the reduction in the required RaptorQ overhead with user cooperation.
A Cellular Vehicle to Vehicle (V2V) safety broadcast model is proposed for transmitting
emergency safety messages with interference from other vehicles using different traffic conditions, mobility models, road structures and environments. This safety broadcast model is based on Half Duplex (HD) operation with Single Carrier Frequency Division Multiple Access (SCFDMA) in the Physical layer, uses semi-persistent sensing for resource allocation in the MAC layer and RaptorQ codes in the Application layer. Coverage improvements of up to 195m (rural) and 75m (urban) with a reduction of delay by 50% are seen by using Cellular V2V with RaptorQ codes for the dense traffic case as compared to standard IEEE 802.11p/WAVE with repetition codes. For the traffic jam case, results show that Cellular V2V using Full Duplex (FD) operation can double the capacity and reduce the delay <5ms even in the challenging case (half the LTE time-frequency resources are available for V2V transmissions) as compared to the HD operation.
... In this work, to determine whether or not an SCI from another vehicle can be decoded, assumptions based on reception power are used. If the reception power is larger than some predefined threshold (Receiver sensitivity, R X sen assumed in this work), the SCI is deemed to be decodable [10]. R X sen is defined as the minimum receive power level to provide a data throughput greater than 95% of the maximum possible throughput [11]. ...
... In [14], the authors compare the performance of IEEE 802.11p and cellular V2V for periodic safety messages without considering any co-channel interference in a line of sight (LOS) highway model. The authors in [10] study autonomous resource selection for V2V communication in urban scenarios. They consider the co-channel interference from other vehicles especially at the street crossings and improve performance using sensing with resource partitioning algorithms. ...
... HD to FD variation in the safety broadcast system can be controlled by the self interference cancellation parameter ksi in equation (10). The vehicles selects the available resources in both time (subframes) and frequency (subchannels) by sensing the channel. ...
Low delay and high reliability of safety broadcast messages are critical to future intelligent transport systems (ITS). The main objective of this paper is to propose a novel safety broadcast system model to satisfy the latency and reliability requirements of vehicle-to-vehicle (V2V) applications. Second, using this proposed model, a comprehensive performance evaluation is conducted under different technologies (cellular and IEEE 802.11p) for different vehicle densities in rural and urban scenarios based on a realistic system-level simulator. The performance is further improved by using application layer raptor Q codes as compared to the standard repetition codes proposed in the literature. Results show a coverage improvement of 144 m (rural) and 45 m (urban) using cellular V2V with raptor Q codes as compared to IEEE 802.11p for a target end-to-end delay of 5 ms. This is because IEEE 802.11p suffers from preamble channel estimation especially in urban areas with high collision rate due to the hidden terminal problems. In case of a traffic jam, with higher vehicle density, full duplex (FD) operation is needed for cellular V2V to achieve the target delay. FD operation satisfies the latency requirements even when half the resources are available for V2V transmissions.
... While the algorithm specified by 3GPP [18], [19] is addressed in [10], the others focus on new approaches. In both [11] and [12], resources are grouped into sub-pools that are associated with vehicles based on their direction and/or position on the road, thus reducing the risk of collisions due to allocations performed by terminals hidden to each other (mainly because of the distance in the highway scenarios and of the buildings in the urban areas). In [13], the adoption of maps of the resources sent within the CAMs is proposed. ...
... The main aspects of the cited papers dealing with resource [11] Before Release 14 Autonomous, based on positions Not specified simulator Random allocation Kim et al. [12] Before Release 14 Autonomous, based on positions Not specified simulator Random allocation Cecchini et al. [13] Beyond Release 14 Autonomous, with observed occupations piggybacked in data packets ...
... From (37), we can also write the corresponding CDF as 11 (a) Example of case 1. ...
Short-range wireless technologies will enable vehicles to communicate and coordinate their actions, thus improving people's safety and traffic efficiency. Whereas IEEE 802.11p (and related standards) had been the only practical solution for years, in 2016 a new option was introduced with Release 14 of long term evolution (LTE), which includes new features to enable direct vehicle-to-vehicle (V2V) communications. LTE-V2V promises a more efficient use of the channel compared to IEEE 802.11p thanks to an improved PHY layer and the use of orthogonal resources at the MAC layer. In LTE-V2V, a key role is played by the resource allocation algorithm and increasing efforts are being made to design new solutions to optimize the spatial reuse.In this context, an important aspect still little studied, is therefore that of identifying references that allow: 1) to have a perception of the space in which the resource allocation algorithms move; and 2) to verify the performance of new proposals. In this work, we focus on a highway scenario and identify two algorithms to be used as a minimum and maximum reference in terms of the packet reception probability (PRP). The PRP is derived as a function of various parameters that describe the scenario and settings, from the application to the physical layer. Results, obtained both in a simplified Poisson point process scenario and with realistic traffic traces, show that the PRP varies considerably with different algorithms and that there is room for the improvement of current solutions.
... Previous works [5] [8] [9] evaluate the sustainability of C-V2V for safety applications and in [6], the authors compare the performance of C-V2V with IEEE 802.11p. However, all these works do not consider interference from other vehicles or FEC in the application layer. ...
... given by equation (8) before adding upper layer headers ℎ . The Raptor Q encoder generates repair symbols with 0.5 ≤ ≤ 0.95 using equation (9) for each of the fragmented source symbols. Note that CR=1 represents no raptor and a CR=0.5 represents an additional 50% overhead. ...
... V2V Parameters[9] ...
... Routing methods overlook the crucial aspect of resource availability within the network, which is a significant factor in achieving successful routing. In order to autonomously select suitable radio resources for V2V communications, numerous studies have been conducted in cellular networks for various scenarios like highway [10] or urban [11]. Authors in [10] emphasize localization-based resource management controlled by the network, utilizing the location information of vehicles, and introduces an algorithm based on the concept of reuse distance. ...
... Authors in [10] emphasize localization-based resource management controlled by the network, utilizing the location information of vehicles, and introduces an algorithm based on the concept of reuse distance. In [11], authors focus on resource partitioning based on vehicles direction along with a sensing-based collision avoidance mechanism. ...
Using a multi-hop routing protocol for unicast vehicle-to-vehicle (V2V) communications is crucial to facilitate data relaying from one vehicle to a distant one. The dynamic behavior of vehicular ad-hoc networks (VANETs) and unstable relays often cause frequent disconnections or switchovers, leading to higher latency, diminished reliability, and increased resource use. The stability of these routes depends not just on link connectivity, but also on the availability of adequate resources. Although numerous studies have explored traditional VANET routing protocols to tackle these issues, they often neglect the critical aspect of resource availability. In this study, we focus on a V2V routing method that considers resource availability, assuming the use of a geo-based resource allocation framework. In the proposed resource-aware approach, we utilize deep learning to predict vehicle trajectories and traffic load in various areas. The proposed resource-aware routing protocol aims at improving both spectrum efficiency and route stability by employing distance between vehicles, traffic load, and resource availability of areas to manage emergency messages (EMs) more efficiently and reduce unnecessary rebroadcasting and congestion. Our simulation results reveal that our proposed method surpasses traditional protocols in terms of packet reception ratio (PRR), latency, and average hop count.
... The authors in refs. [25][26][27], and [28] are interested in Mode 4 resource allocation problem and propose new methods based on SPS modifications. In ref. [25], the proposed scheme aims to minimise the interferences between Vehicle User Equipments (VUEs) based on their header directions (e.g. ...
... [25][26][27], and [28] are interested in Mode 4 resource allocation problem and propose new methods based on SPS modifications. In ref. [25], the proposed scheme aims to minimise the interferences between Vehicle User Equipments (VUEs) based on their header directions (e.g. North-South vs. East-West). ...
The Deployment of new techniques to accommodate high data throughput, significant reliability, and quality of service (QoS) delivery prompts the use of 4G and 5G networks in several applications. In these networks, Vehicle‐to‐Everything (V2X) communications authorised by device‐to‐device cellular links (D2D) have gained momentum because of their potential to improve road safety, efficiency, and convenience. This improvement is to be provided by different types of V2X communications, including Vehicle‐to‐Pedestrian (V2P), Vehicle‐to‐Vehicle (V2V), Vehicle‐to‐Infrastructure (V2I), and Vehicle‐to‐Network (V2N) communications. However, considering several limiting factors such as mobility and increasing number of vehicles, efficiency of using wireless resources is a challenging task. Indeed, different research works on V2X radio resource allocation have been studied and evaluated with respect to several criteria. In this study, a survey of recent works but in a different way synthesising radio resource allocation methods is presented. Resource allocation classification into different categories is proposed. This classification is related to three main factors. The first takes into account the selection mode factor. It highlights the use of different approaches in each of the centralised, distributed, and mixed modes. The second one takes into account the considered performance criteria, including capacity, priority, delay etc. The last one focuses on the methods and scenarios used to evaluate a resource allocation approach.
... In addition to these works, analytical models are provided in [19,20]. On the other hand, methods to reduce the packet collisions are proposed in [21][22][23][24][25][26][27][28][29][30][31]. In [21][22][23], each of the UEs notifies other UEs of resources virtually reserved by the UE in advance. ...
... However, these methods are not preferable from the viewpoint of compatibility with the standard because they require additional information and the format of control information needs to be changed. Geo-based resource allocation methods corresponding to the position of the UEs on a road have been proposed in [27][28][29], and can avoid packet collisions with the UEs located on Non-Line of Sight (NLOS). Even so, it is necessary to know a correspondence between the UE position and the resource pool in advance, and it is difficult to achieve a high degree of efficiency unless all UEs follow the same rule. ...
Vehicle to Everything (V2X) is a technology that includes communication between the vehicles and everything such as Vehicle to Vehicle (V2V), Vehicle to Infrastructure (V2I), and Vehicle to Pedestrian (V2P). Long Term Evolution (LTE) V2X based on LTE supports a sidelink communication in which User Equipment (UE) communicates with each other. In Mode 4 of the sidelink communication, the UE autonomously selects a radio resource that is not expected to be used by other UEs based on sensing information. However, a resource can be selected by simultaneous UEs and packet collisions occur because of the periodic resource reselection. In this paper, we propose two resource selection methods for the reselection using information originally included in the control information. Through computer simulations, we show that the proposed methods can improve the packet reception rate without requiring restrictions such as additional information. The main strength of this method is that it effectively utilizes the information contained in Resource Reservation Interval (RRI), which is used in the Semi-Persistent Scheduling wireless resource allocation algorithm. In this research, the value of RRI, which has been used in standards, is utilized to improve performance while maintaining compatibility. Since our method is designed under conditions that maintain compatibility with existing standards, it may or may not have a significant effect, but it does not degrade performance.
... Trois contributions principales [40] [41] [42] sont soulignés dans la suite. Le premier ouvrage de [40] est composé de deux phases. ...
... Trois contributions principales [40] [41] [42] sont soulignés dans la suite. Le premier ouvrage de [40] est composé de deux phases. Alors que la première consiste à partitionner le pool de ressources en fonction des directions de déplacement des véhicules, la seconde phase a appliqué un schéma d'évitement de l'allocation des ressources basé sur la détection qui détermine la liste des véhicules interférents et construit ensuite une carte d'utilisation des ressources basée sur l'occupation des ressources. ...
Les réseaux véhiculaires constituent une classe de réseaux mobiles à part entière présentant l’originalité de permettre aux véhicules de communiquer les uns avec les autres dans le cadre d'une mobilité spatiale élevée ainsi qu’avec les réseaux cellulaires et les réseaux de communication déployés sur l’infrastructure routière. En vue de supporter les communications des véhicules autonomes de niveau 5, ces réseaux doivent offrir une QoS adaptée aux contraintes temporelles critiques des communications tout en garantissant un haut niveau d’intégrité des données échangées. La technologie LTE utilisée dans les réseaux mobiles cellulaires et qui est dotée d’un cadre rigoureux de QoS a été choisie par le 3GPP (Release 14) pour la communication dans les réseaux véhiculaires sous la référence LTE-V2X/ cellular V2X. La Release 14 introduit deux modes (3,4) de communication LTE spécialement conçus pour les communications V2V. Dans le mode 3, la sélection des canaux radios est gérée par la station de base eNodeB. Dans le mode 4, les véhicules sélectionnent leurs ressources radio d’une manière autonome indépendamment de toute couverture du réseau cellulaire. Dans la littérature, différents algorithmes d’allocation de ressources pour les modes 3 et 4 ont été proposés.Dans la première partie de la thèse, on s’intéresse au mode 3 qui répond aux besoins du monitoring des véhicules autonomes de niveau 5 par l’infrastructure déployée sur la route et dans le Cloud. Une étude exhaustive des propositions existantes dans littérature montre que la majorité des solutions proposées ne traitent que les messages périodiques (non-safety ex. CAM) tout en assurant un minimum de sécurité. Donc, nous avons introduit les messages apériodiques (safety ex. DENM) qui sont générés dans des situations critiques (accident, bouchon). Nous avons proposé une politique d'allocation des ressources basée sur un système de priorité avec la garantie stricte d'une capacité minimale pour les applications critiques et un partage dynamique de la capacité restante avec les autres applications. Nous avons proposé également une nouvelle technique de réutilisation des ressources pour les deux types de messages (critiques et moins critiques) qui permet d’utiliser efficacement la capacité du réseau tout en satisfaisant les exigences des applications critiques sans pénaliser les applications moins critiques.La technologie LTE-V présente une étape importante vers le réseau V2X/5G. Ce réseau 5G offre, par le biais de l’URLLC, une haute intégrité et une faible latence pour les applications temps réel critiques. De plus, avec le concept du « Network Slicing », l’architecture fonctionnelle du réseau 5G offre la portabilité du réseau véhiculaire avec ses services à côté d’autres réseaux de services au sein du réseau mobile 5G. Nous avons choisi d’intégrer l’architecture du réseau véhiculaire 5G dans un même slice au niveau du réseau d’accès ce qui permet de bénéficier du gain statistique en termes de l’utilisation des ressources radios. On s'est intéressé aux couches MAC et physique NR. Nous avons étudié l’allocation dynamique des ressources radios entre les communications URLLC critiques et les communications de streaming portés dans un même Slice. L’ordonnanceur utilisé pour l’allocation des ressources est spécifié pour gérer dynamiquement les ressources spectrales entre les flux URLLC critiques et les flux de streaming échangés entre véhicules et les serveurs d’applications. Nous avons proposé plusieurs modèles statistiques de flux échangés et analysé par simulation la QoS offerte dans le réseau d’accès aux flux critiques/streaming. Nous avons également proposé un modèle analytique markovien quasi-exact de la traversée des couches MAC/Physique du flux URLLC avec comme objectif de dimensionner un mécanisme de contrôle d’admission (CAC) des flux critiques dans le slice et de garantir la QoS requise par ces flux.
... RB, with least interference, is selected for the next transmission to avoid interference with neighboring vehicles [12,13]. Authors in [14] have proposed partitioning of resources based on the direction in which VUEs are heading to avoid error in power sensing due to hidden nodes approaching at intersections. 3GPP Rel-15 proposes linear averaging of power sensed on an RB over a specified period hereafter termed as sensing period. ...
... (10) by substituting the value of a n f ;k and g n f ;k from Eqs. 12 and (13) respectively. Now, after c-Learning weighted exponential averaging is performed according to (14). The process of resource reselection using CARRs strategy is shown in Fig. 3. ...
C-V2X (Cellular Vehicle-to-Everything) standard introduced in 3GPP Release-14 is emerging as a potential technology for Cooperative Awareness Message (CAMs) dissemination among connected vehicles. But to attain its full potential, optimal resource scheduling and interference management must be enforced. To address this issue, we propose a weighted exponential averaging based Context-Aware Resource Reselection scheme (CARRs), enabling the periodic exchange of CAMs in a vehicular network. The proposed strategy allows autonomous resource selection by performing continuous power sensing and cooperative learning with the neighbors within the safety zone. CARRs is a two-stage learning process. In the first stage, it learns the exponential weighing factor for each resource available in the Vehicle-to-Vehicle resource pool and performs resource reselection. In the second stage, it learns to select transmit power level based on the interference experienced over the reselected resource. It is established through numerical results that CARRs outperforms the existing strategies. Packet reception ratio, average error rate, average blocking rate and update delay are considered as the performance metrics. CARRs improves packet reception ratio by 3.1% while reducing the average error rate by 28.2% and lowering update delay by 4.5% in comparison to existing schemes.
... 2) Cellular Network based Vehicular Communication Modes: Cellular-V2V: Transitioning from DSRC, as shown in Fig. 3, LTE-based V2V communication presents a cost-effective, broader coverage alternative [137], [138]. This mode, part of LTE's ProSe services, adopts device-to-device (D2D) communication, offering a centralized approach beneficial for traffic monitoring and control [139]- [141]. LTE-V2V operates through the PC5 interface and LTE-Uu interface, where PC5 Mode 3 is under cellular control and Mode 4 functions autonomously [142]- [144]. ...
This survey explores the transformative role of reconfigurable intelligent surface (RIS) technologies in vehicular communication systems. It begins by introducing key RIS concepts and classifying them into passive, active, and hybrid types, with particular focus on beyond diagonal RIS (BD-RIS) and its various architectural designs. The study then delves into the evolution of vehicular communication technologies, followed by channel modeling and strategies to ensure long-term system adaptability. The survey further investigates key technological advancements, such as advanced channel modeling and estimation techniques, strategies for optimizing network sum-rate and energy efficiency (EE), and enhancing security within vehicular networks through RIS. Additionally, it examines the integration of RIS with vehicular edge computing (VEC) frameworks, its potential in unmanned aerial vehicle (UAV) supported networks, and its application in visible light communication (VLC) systems. The analysis also considers the synergy between RIS and mmWave technologies. Then, a comprehensive performance assessment is conducted to evaluate the impact of these advancements in RIS-based vehicular networks. The aim is to thoroughly elaborate, compare, and evaluate the literature concerning network scenarios, RIS details, methodologies, and optimization objectives. Conclusively, the research highlights key findings and charts future research directions, pinpointing imminent technical challenges and emerging areas for further exploration in the rapidly evolving landscape of vehicular communications.
... It is still difficult to allocate time-frequency resources efficiently and consistently across various vehicle user equipments (VUEs), especially in crowded urban areas. For an urban V2V communication situation, an innovative autonomous resource selection strategy is put forth in this work [7]. Jan Lansky, Amir Masoud Rahmani and Mehdi Hosseinzadeh according to their research study they state that the task of routing in these networks is difficult. ...
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... Similarly, to avoid resource conflicts, a resource pre-emption mechanism considering priority was proposed in [26], and a two-stage resource management mechanism based on vehicle density was designed in [27]. Additionally, an automatic resource selection mechanism was proposed in [28] based on the heading direction to minimize potential conflicts among neighboring resources. To adjust the maintenance period of the resource adaptively according to the state of each user, an algorithm for adaptively modifying the reselection probability according to the user channel status information (CSI) was proposed in [19]. ...
Cellular vehicle-to-everything (C-V2X) facilitates direct communication between vehicles and other user equipment (UE) to improve the efficiency of the Internet of vehicles communication through sidelink. In addition, in the new radio vehicle-to-everything (NR-V2X) Mode 2, users can automatically select resources using the conventional sensing-based semi-persistent scheduling (SB-SPS) resource selection algorithm. This mechanism allows users to generate a list of available resources after a sensing window, after which the users can randomly select resources, and the resource can be used continuously over multiple periods before reselection. However, during the sensing window, neighbors may generate a similar list of available resources, and random selection may lead to resource conflicts. This phenomenon may lead to deteriorated communication performance and increased latency due to incorrect reception. Therefore, this paper proposes a reuse distance-aided resource selection (RD-RS) method which integrates resource reuse distance judgement with SB-SPS to mitigate resource conflicts and interference caused by random selection. Moreover, the reuse distance judgement is performed before the final resource selection, and whether the user will select the current resource depends on the reuse distance between that user and other occupiers. Furthermore, the performance of the proposed scheme is compared with other algorithms. Simulation results show that the proposed RD-RS not only achieves a higher packet reception ratio (PRR) but also effectively reduces the inter-packet gap (IPG). Moreover, in specific scenarios, the proposed method outperforms conventional schemes by 9% in terms of PRR and 70% in terms of Range.
... It is of great significance to study how to reuse cellular resources as much as possible under the premise that cellular users are not seriously disturbed. Literature [8] proposed a greedy algorithm for reusing distance based on the location of vehicles. However, the greedy algorithm can only get the optimal solution under the current situation and cannot guarantee the global optimal solution. ...
As a special Mobile Ad-hoc Network (MANET), Vehicular Ad-hoc Network (VANET) plays a very important role in the future intelligent transportation system. In order to solve the problems of unstable communication connection, fast network topology change and low communication resource utilization caused by high vehicle mobility in VANET, a low-complexity resource allocation algorithm based on vehicle cluster is proposed. Firstly, considering the speed, position and moving direction of the vehicles, a vehicle clustering algorithm based on movement consistency is proposed to cluster the vehicles and keep the vehicle cluster stable. Secondly, a low-complexity resource allocation algorithm is proposed to improve the utilization rate of communication resources, which is constrained by the interference caused by the vehicle clusters to the cellular users. Simulation results show that the proposed algorithm has low complexity and can better maintain the stability of vehicle clusters and improve the system capacity in the common complex Internet of Vehicles (IoV) scenarios in cities.
... References [44], [69], [70], [71] investigate the effect of MAC and PHY layer parameters on the performance of baseline LTE-V2X. References [72], [73], [74], [75] discuss the resource allocation protocol of LTE-V2X Uu and PC5 interfaces. In [76], authors present a system-level evaluation in terms of different types of transmission error, such as propagation errors, packet collision, and errors due to the half-duplex operation. ...
Vehicle-to-Vehicle (V2V) communication systems have an eminence potential to improve road safety and optimize traffic flow by broadcasting Basic Safety Messages (BSMs). Dedicated Short-Range Communication (DSRC) and LTE Vehicle-to-Everything (V2X) are two candidate technologies to enable V2V communication. DSRC relies on the IEEE 802.11p standard for its PHY and MAC layer while LTE-V2X is based on 3GPP’s Release 14 and operates in a distributed manner in the absence of cellular infrastructure. There has been considerable debate over the relative advantages and disadvantages of DSRC and LTE-V2X, aiming to answer the fundamental question of which technology is most effective in real-world scenarios for various road safety and traffic efficiency applications. In this paper, we present a comprehensive survey of these two technologies (i.e., DSRC and LTE-V2X) and related works. More specifically, we study the PHY and MAC layer of both technologies in the survey study and compare the PHY layer performance using a variety of field tests. First, we provide a summary of each technology and highlight the limitations of each in supporting V2X applications. Then, we examine their performance based on different metrics.
... However, the lack of signaling also means contention for the RB selection and the probability of resource collisions [32]. The probability of resource collisions is bound to increase for densely populated networks [16]. This scenario of resource collisions among multiple vehicles and the broadcast nature of vehicle safety messages brings Release 14 of the 3GPP away from its design objectives of LTE-V2X for vehicular broadcast communications. ...
Effective communication in vehicular networks depends on the scheduling of wireless channel resources. There are two types of channel resource scheduling in Release 14 of the 3GPP, i.e., (1) controlled by eNodeB and (2) a distributed scheduling carried out by every vehicle, known as Autonomous Resource Selection (ARS). The most suitable resource scheduling for vehicle safety applications is the ARS mechanism. ARS includes (a) counter selection (i.e., specifying the number of subsequent transmissions) and (b) resource reselection (specifying the reuse of the same resource after counter expiry). ARS is a decentralized approach for resource selection. Therefore, resource collisions can occur during the initial selection, where multiple vehicles might select the same resource, hence resulting in packet loss. ARS is not adaptive towards vehicle density and employs a uniform random selection probability approach for counter selection and reselection. As a result, it can prevent some vehicles from transmitting in a congested vehicular network. To this end, the paper presents Truly Autonomous Resource Selection (TARS) for vehicular networks. TARS considers resource allocation as a problem of locally detecting the selected resources at neighbor vehicles to avoid resource collisions. The paper also models the behavior of counter selection and resource block reselection on resource collisions using the Discrete Time Markov Chain (DTMC). Observation of the model is used to propose a fair policy of counter selection and resource reselection in ARS. The simulation of the proposed TARS mechanism showed better performance in terms of resource collision probability and the packet delivery ratio when compared with the LTE Mode 4 standard and with a competing approach proposed by Jianhua He et al.
... So, vehicles that have less geographic distance from each other and almost the same traffic pattern are clustered in the same group to decrease the signalling overhead of BSs. Another autonomous resource selection algorithm has been proposed in [19], which consists of two main steps. In the first step, a heading direction based partitioning of resource pool is proposed for eliminating the interference between vehicles that are approaching intersections from orthogonal directions, and in the second step, a sensing-based approach is utilized to diminish further interference between each subresource pool. ...
Vehicle to Vehicle (V2V) communication has recently been considered in 4G and 5G cellular networks. One of the challenging issues in cellular V2V is allocating radio resources to the vehicles. Although previous work have addressed this issue, the fast varying nature of vehicular traffic and its regularities implies that the mobility of the vehicles should be more attended. To this goal, we propose an autonomous geo-based resource selection algorithm that uses deep learning to predict vehicle locations in the future and alleviate the computation and signalling overhead of the cellular infrastructure in contrast to previous geo-based resource allocation algorithms. We utilize the current and the future of vehicle densities in a formulated matching problem to find the optimum assignment of sub-resource pools to geographic areas. Simulation results of a highway with diverse density scenarios and different number of available resources show that the proposed method guarantees a considerable reduction in computation and signalling overhead while in low awareness ranges, it provides up to 10% improvement in Packet Reception Ratio (PRR) and the error rate of vehicles compared to the previous Dynamic Geo-based Resource Selection Algorithm (DGRSA). The proposed method also provides up to 15% improvement in PRR and error rate compared to the modified DGRSA, which we have changed to run with an overhead equal to the overhead of our proposed method. Furthermore, our results demonstrate up to 67% and 76% improvement in blocking rate compared to DGRSA and modified DGRSA, respectively.
... Urban and highway are treated separately. In [109], sub-pools are created to separate the allocation of vehicles driving on perpendicular roads, which are subject to frequent non-line-of-sight (NLOS) conditions. In [110], a geo-based distributed allocation is proposed, based on the position exchanged by the vehicles and trying to maximize the distance of resource reuse. ...
Connected and fully automated vehicles are expected to revolutionize our mobility in the near future on a global scale, by significantly improving road safety, traffic efficiency, and traveling experience. Enhanced vehicular applications, such as cooperative sensing and maneuvering or vehicle platooning, heavily rely on direct connectivity among vehicles, which is enabled by sidelink communications. In order to set the ground for the core contribution of this paper, we first analyze the main streams of the cellular-vehicle-to-everything (C-V2X) technology evolution within the Third Generation Partnership Project (3GPP), with focus on the sidelink air interface. Then, we provide a comprehensive survey of the related literature, which is classified and critically dissected, considering both the Long-Term Evolution-based solutions and the 5G New Radio-based latest advancements that promise substantial improvements in terms of latency and reliability. The wide literature review is used as a basis to finally identify further challenges and perspectives, which may shape the C-V2X sidelink developments in the next-generation vehicles beyond 5G.
... A two-step distributed RA scheme was proposed in [71] for out-of-coverage (i.e., out of eNodeB coverage) LTE V2V communication. In the first step, RBs are assigned based on the heading directions of vehicles. ...
Vehicular networks, an enabling technology for Intelligent Transportation System (ITS), smart cities, and autonomous driving, can deliver numerous on-board data services, e.g., road-safety, easy navigation, traffic efficiency, comfort driving, infotainment, etc. Providing satisfactory Quality of Service (QoS) in vehicular networks, however, is a challenging task due to a number of limiting factors such as erroneous and congested wireless channels (due to high mobility or uncoordinated channel-access), increasingly fragmented and congested spectrum, hardware imperfections, and anticipated growth of vehicular communication devices. Therefore, it will be critical to allocate and utilize the available wireless network resources in an ultra-efficient manner. In this paper, we present a comprehensive survey on resource allocation schemes for the two dominant vehicular network technologies, e.g. Dedicated Short Range Communications (DSRC) and cellular based vehicular networks. We discuss the challenges and opportunities for resource allocations in modern vehicular networks and outline a number of promising future research directions.
... The vehicle's speed also is an important parameter that affects the communication link and changes the channel characteristics during communication. [10] The V2V channel is distinct from that of many typical communication system channels. The closest comparison may be to the cellular channel with some differences between them such as the antenna heights of both transmitter (Tx) and receiver (Rx) in V2V are low and mobile [11]. ...
Modern wireless communication like 5G systems are expected to serve a wider range of scenarios than current mobile communications systems. One of the major network applications related to 5G is Vehicle-to-Vehicle (V2V) communication that improves vehicle road safety, enhances traffic and travel efficiency, and provides convenience and comfort for passengers and drivers. However, supporting high mobility is a challenge on the air interface. Accordingly, multicarrier modulation as multiple access is used to enhance the connection between vehicles and to overcome this challenge. In this paper, two multicarrier modulations are simulated. The first one is the Orthogonal Frequency Division Multiplexing (OFDM) while the second one is the Filter Bank Multi-Carrier with Offset Quadrature Amplitude Modulation (FBMC/OQAM) which is called FBMC. Simulation results show that all waveforms have comparable BER performance. The throughput of the FBMC is greater than the OFDM and the spectral efficiency is increased according to the use of the OQAM modulation. The FBMC throughput reaches 5 Mbps while the OFDM reaches 4 Mbps; these results are due to the higher usable bandwidth and because of using filters in FBMC which reduces the effect of Cyclic Prefix (CP) on the signal especially when CP is large in OFDM.
Index Terms: Multicarrier, V2V, 5G, OFDM, FBMC
... The performance improvement and analysis of C-V2X mode 4 and the SPS scheme have increasingly being investigated recently. For instance, the performance of the SPS algorithm in [16] and [17] is generally analyzed by simulations on the packet delivery ratio (PDR). The theoretical quantitative studies on the upper bound of network capacity are present in [18] and [19], which take into account the received signal-to-interference ratio from the spatial positional perspective. ...
The Cellular Vehicle-to-Everything (C-V2X) networks can support direct vehicle-to-vehicle V2V communications via sidelink/PC5 interface without cellular infrastructure support. The sensing-based Semi-Persistent Scheduling (SPS) scheme is to allow vehicles to autonomously reserve and select radio resources. However, the common sensing nature of distributed SPS algorithm gives rise to that C-V2X distributed communications can be challenged by the resource selection collisions, especially in aperiodic traffic, which resulting in low reliability. In this paper, we propose a short term sensing based resource selection (STS-RS) scheme to reduce packet collisions due to resource contention, where a short term sensing duration is configured at the beginning of the resource unit right before resource selection, and whether the packet is ultimately transmitted on the selected resource depends on the sensing result. Furthermore, analysis models of the performance for the proposed STS-RS scheme and SPS scheme defined in C-V2X mode 4 are investigated. Finally, simulations and numerical results show that the STS-RS scheme significantly reduces the packet collisions and increase the C-V2X direct communication performance compared to SPS scheme.
... Among these wireless technologies, there is no doubt that a cellular technology (including 3G, 4G, and 5G) is a good candidate for V2X communication because it provides wide coverage and reliable connectivity with low latency and a high data rate. The cellular technology is based on a centralized communication approach where a base station provides transmission coverage [13]. Another candidate among the wireless technologies of mobile devices to be considered in C-ITS is Wi-Fi Direct. ...
In the vehicular ad-hoc networks (VANETs), wireless access in vehicular environments (WAVE) as the core networking technology is suitable for supporting safety-critical applications, but it is difficult to guarantee its performance when transmitting non-safety data, especially high volumes of data, in a multi-hop manner. Therefore, to provide non-safety applications effectively and reliably for users, we propose a hybrid V2V communication system (HVCS) using hierarchical networking architecture: a centralized control model for the establishment of a fast connection and a local data propagation model for efficient and reliable transmissions. The centralized control model had the functionality of node discovery, local ad-hoc group (LAG) formation, a LAG owner (LAGO) determination, and LAG management. The local data propagation indicates that data are transmitted only within the LAG under the management of the LAGO. To support the end-to-end multi-hop transmission over V2V communication, vehicles outside the LAG employ the store and forward model. We designed three phases consisting of concise device discovery (CDD), concise provisioning (CP), and data transmission, so that the HVCS is highly efficient and robust on the hierarchical networking architecture. Under the centralized control, the phase of the CDD operates to improve connection establishment time, and the CP is to simplify operations required for security establishment. Our HVCS is implemented as a two-tier system using a traffic controller for centralized control using cellular networks and a smartphone for local data propagation over Wi-Fi Direct. The HVCS’ performance was evaluated using Veins, and compared with WAVE in terms of throughput, connectivity, and quality of service (QoS). The effectiveness of the centralized control was demonstrated in comparative experiments with Wi-Fi Direct. The connection establishment time measured was only 0.95 s for the HVCS. In the case of video streaming services through the HVCS, about 98% of the events could be played over 16 frames per second. The throughput for the streaming data was between 74% to 81% when the vehicle density was over 50%. We demonstrated that the proposed system has high throughput and satisfies the QoS of streaming services even though the end-to-end delay is a bit longer when compared to that of WAVE.
... A two-step distributed RA scheme was proposed in [64] for out-of-coverage (i.e., out of eNodeB coverage) LTE V2V communication. In the first step, RBs are assigned based on the heading directions of vehicles. ...
Vehicular networks, an enabling technology for Intelligent Transportation System (ITS), smart cities, and autonomous driving, can deliver numerous on-board data services, e.g., road-safety, easy navigation, traffic efficiency, comfort driving, infotainment, etc. Providing satisfactory quality of service (QoS) in vehicular networks, however, is a challenging task due to a number of limiting factors such as hostile wireless channels (e.g., high mobility or asynchronous transmissions), increasingly fragmented and congested spectrum, hardware imperfections, and explosive growth of vehicular communication devices. Therefore, it is highly desirable to allocate and utilize the available wireless network resources in an ultra-efficient manner. In this paper, we present a comprehensive survey on resource allocation (RA) schemes for a range of vehicular network technologies including dedicated short range communications (DSRC) and cellular based vehicular networks. We discuss the challenges and opportunities for resource allocations in modern vehicular networks and outline a number of promising future research directions.
... Besides, existed studies indicate the inefficiency of LTE-V2X mode 4 to schedule resources when the transmissions are aperiodic [3]. In [4], an enhanced autonomous resource selection scheme is proposed for LTE V2V communication. In the first stage, resources are partitioned based on vehicle moving direction. ...
... Resource allocation making the use of vehicles' geographical position has also been put forward as a promising mechanism [5]. [6] proposes a distributed autonomous resource selection scheme which bases on vehicle heading direction. ...
... Some other resource selection algorithms need to work in cooperation to help the VUE select a proper resource block in the corresponding sub resource pool [9,10,[13][14][15]. In [16], a novel algorithm that combines the energy sensing algorithm and the geo-based algorithm together is proposed and the paper modifies the energy sensing algorithm to settle the near-far problem caused by in-band emission. The work in [17] continues to use the resource selection algorithm in device-to-device (D2D) and adds geographic information into this algorithm to apply in V2V broadcast communication. ...
The geography-based (geo-based) resource selection algorithm is one of the feasibility schemes of third-generation partnership project (3GPP). However, most researches about it ignore the impacts of boundary interference and vehicle density. Therefore, this paper firstly puts forward an enhanced geo-based resource selection algorithm (EGRSA). This algorithm can eliminate the boundary interference through randomizing subframes of each sub resource pool. On the basis of EGRSA, the dynamic geo-based resource selection algorithm (DGRSA) is proposed to guarantee the reliability of communication when vehicle density is nonuniform. In DGRSA, mapping relationships are changed dynamically by grouping and optimal matching, and the size of each sub resource pool can also be adjusted. The system level simulation results indicate that the EGRSA is able to improve the packet reception ratio (PRR) and reduce the number of boundary collisions. Meanwhile, the proposed DGRSA further promotes the PRR when vehicle density is in a non-uniformity distribution because of traffic jam.
We explore a new approach to radio resource allocation for vehicle-to-vehicle (V2V) communications in case of out-of-coverage areas that are delimited by network infrastructure. By collecting and predicting information such as vehicle velocity, density and message traffic, the network infrastructure ensures reliability of the V2V services. We propose reserving required amount of resources for services that cannot be pre-scheduled (e.g., emergency braking, crash notifications, etc.), and scheduling those services that can be pre-scheduled (e.g., platooning). We analyze the resource reservation as a function of target reliability under varying vehicle densities and sizes of out-of-coverage area. For pre-scheduled services, we explore how variations in the vehicle velocities and predictions affect successful transmissions. The results indicate that increase in required reliability does not penalize the system prohibitively. On the other hand, speed prediction errors decrease the transmission success rate considerably, thus calling for a more flexible scheduler design.
Vehicle environmental awareness is a crucial issue in improving road safety. Through a variety of sensors and vehicle-to-vehicle communication, vehicles can collect a wealth of data. However, to make these data useful, sensor data must be integrated effectively. This paper focuses on the integration of image data and vehicle-to-vehicle communication data. More specifically, our goal is to identify the locations of vehicles sending messages within images, a challenge termed the vehicle identification problem. In this paper, we employ a supervised learning model to tackle the vehicle identification problem. However, we face two practical issues: first, drivers are typically unwilling to share privacy-sensitive image data, and second, drivers usually do not engage in data labeling. To address these challenges, this paper introduces a comprehensive solution to the vehicle identification problem, which leverages federated learning and automatic labeling techniques in combination with the aforementioned supervised learning model. We have validated the feasibility of our proposed approach through experiments.
An autonomous Vehicle to Vehicle (V2V) communication mode, which allows V2V communication in out of eNB (Evolved Node B) coverage areas, has been recently introduced into the Long Term Evolution (LTE) standard. Recent research has studied the performance of this LTE V2V autonomous mode for an urban intersection use case, where non-line-of-sight (NLOS) communication links are present and it is observed that the overall message transmission performance in LTE V2V is found to degrade drastically in NLOS link conditions. To improve the performance, a vehicle-assisted relaying strategy was proposed. In this scheme, at each time instance, distance of each vehicle from intersection point is computed. Then the vehicle close to the intersection point is nominated as relaying vehicle and will rebroadcast the BSMs (Basic Safety Message) in a selective manner. However, security aspects while relaying the BSM is not being addressed in the suggested model. We cannot reject the possibility that a vehicle can be malicious. A malicious vehicle can manipulate its distance from the intersection point, thereby nominating itself as the relaying vehicle with malicious motives such as to use extra infrastructural faciltiy, curiosity in the messages sent by other vehicles, etc. This work proposes a secure algorithm for finding the most appropriate relaying vehicle to address this security vulnerability so that a vehicle can no longer falsify its location information.
The concept of energy transfer between two vehicles and communication between them is a promising one for the future of electrified transportation sector. In response to the growing research and interest in vehicle-to-vehicle (V2V) technology , this article provides an in-depth review on the actual energy transfer between two vehicles and their communication aspects. The literature is addressed to analyze power electronics topologies for successful V2V power transfer and compare V2V charging optimization techniques. Communication protocols and standards relevant to V2V technology are also discussed with a focus on their potential applications for improving transportation safety and efficiency. Further, challenges faced by existing V2V power transfer solutions and the commercial products available for implementing V2V charging are described. In contrast to other literature surveys, this paper provides a comprehensive overview of V2V power transfer and communication technologies with implications for the future of sustainable electrified transportation. The study and discussion of over 300 papers on the topic are encompassed in this paper. Index Terms-Electric vehicle (EV); V2V power transfer; On-board charger; Off-board charger.
The New Radio Vehicle-to-Everything (NR-V2X) technology investigated by the Third Generation Partnership Project (3GPP) explores the high reliability requirement to support message dissemination by vehicle-to-vehicle (V2V) distributed communications for safety applications via a direct communication interface. However, the natural commonality of distributed resource selection may lead to severe resource collisions in a dense high mobility environment. In this paper, we propose a UE-scheduling resource allocation scheme to reduce distributed resource contentions, where vehicles are clustered autonomously based on orthogonal resource sets detection and the cluster size is determined by the cluster-joining threshold. In addition, the algorithms of clustering maintenance are designed to improve the stability of clusters by periodically checking the status of the resource sets and the movement of vehicles. Furthermore, a detailed frame structure design is described, and theoretical performance analysis models of the proposed scheme in different traffic scenarios are investigated. Finally, simulations and numerical results demonstrate that the proposed scheme can reduce packet collisions and increase the packet delivery ratio compared to the conventional distributed scheme, and outperforms some existing schemes in cluster stability.
The Vehicle-to-Everything (V2X) speech holds the promise for rising avenue protection and decreasing street accidents with the help of sanctioning dependable and low latency decisions for four wheelers notably Cars. Most of the motors area unit incorporated with the serious duty technology that positive factors excessive speeds, V2X speech turns into obligatory to create sure security. The inter- automobile contact involves passing of records from Vehicle-to-Vehicle (V2V) or Vehicle-to-Infrastructure (V2I) and the other way around. during this paper, a aware effort has been placed on each V2I 2 and V2V speech during a multi-lane superhighway state of affairs, within which insurance set up is volumed through approach of the future Evolution Advanced (LTE-A) road issue unit (RSU) 2 community. A mechanism to dump motors with low Signal-to-Interference-plus-Noise quantitative relation (SINR) is projected and such cars are going to be served with the helpful resource of different motors that have bigger link to the RSU. moreover, we have a tendency to inspect the reforms within the potentialities of achieving purpose outturn and therefore the performance is classified through Brobdingnagian system-degree simulations. Results exhibit that the projected answer offloads calibre V2I hyperlinks to stronger V2V links, and during a similar approach can improve successful transmission likelihood.
Robotic swarms are becoming relevant across different industries. In an indoor factory, collective perception of the environment can be used for increased factory automatization. It requires reliable, high throughput, and low latency communication of broadcasted video data among robots within proximity. We introduce two new decentralized resource allocation schemes that meet these stringent requirements. The two proposed decentralized schemes are denoted as: (i) device sequential, where robots take turns to allocate resources, and (ii) group scheduling, where robots select local group leaders who perform the resource allocation. A comparative evaluation is performed by simulation against a centralized resource allocation scheme and the current 3GPP release 16 NR sidelink mode 2 scheme. Our results show that the two proposed decentralized resource allocation schemes outperform sidelink mode 2 due to the mitigation of the half-duplex problem. The proposed schemes reach the throughput target of 10 Mbps with a reliability of 99.99% for a swarm size of 50 robots.
The main goal behind radio resource management (RRM), in any conventional wireless networks, is to efficiently utilize the available resources. Critical and safety communications have very stringent quality of service requirements on reliability and availability. Consequently, the efficient use of resources becomes more compelling when it deals with this type of application. In this context, cellular vehicle‐to‐everything (C‐V2X) communications, enabled by cellular device‐to‐device (D2D), have recently drawn much attention. This is due to their applicability to road safety and traffic efficiency applications, which require information exchange among road users and road‐side entities. This emerging technology, referred hereinafter as LTE‐V or C‐V2X, supports two different communication modes: 3 and 4. Both of the two modes enable direct vehicle‐to‐vehicle (V2V) communications via PC5 interface. However, they differ on how the radio resources are allocated. Several approaches and algorithms are proposed in the literature to address the resource allocation issue. In this paper, a state of the art of the radio resource allocation strategies was made for LTE‐V technology and a qualitative description was carried out of these different schemes. We proposed a classification of these strategies into different categories. This classification identified the different strengths and weaknesses of each proposal. Up to our knowledge, several surveys concerning resource allocation are published in the context of LTE but very few of them focuses on both RRM and vehicular networks.
A wide variety of works have been conducted in vehicle-to-everything (V2X) communications to enable a variety of applications for road safety, traffic efficiency and passenger infotainment. Although dedicated short-range communications (DSRC) based V2X is already in the deployment phase, cellular based V2X is gaining more interest in academia and industry most recently. This paper surveys the existing work and challenges on LTE and 5G to support efficient V2X communications. First, we present the motivations for cellular based V2X communications. Second, we summarize the LTE V2X architecture and operating scenarios being considered. Third, we discuss the challenges in existing LTE for supporting V2X communications such as physical layer structure, synchronization, multimedia broadcast multicast services (MBMS), resource allocation, security and survey the recent solutions to these challenges. We further discuss the challenges and possible solutions for 5G based vehicular communications. Finally, we discuss the open research issues and possible research directions in cellular based vehicular communications.
An autonomous V2V communication mode (also known as side-link mode 4), which facilitates V2V communication in out of eNB coverage areas, has recently been introduced into the Long term evolution (LTE) standard. Recent research has studied the performance of this LTE-V2V autonomous mode for a highway use case. However, performance analysis for a highway use case cannot be easily applied to an intersection use case as it may contain non-line-of-sight (NLOS) communication links. In this paper, we analyze and evaluate the safety message broadcasting performance of LTE-V2V autonomous mode in an urban intersection scenario. Considering practical path loss models, we present the impact of NLOS communication link on the overall message dissemination performance. Through the analytical and simulation results, we show that the overall message dissemination performance degrades drastically with increasing vehicle density and increasing distance of the transmitting vehicle from the intersection. To improve the performance, we propose a vehicle-assisted relaying scheme in which the relaying vehicle is selected in an autonomous manner. We also present two resource allocation strategies for the relaying vehicle. For low to medium vehicle density along the street, we observe significant improvement in message dissemination through relaying compared to the scheme without relaying.
V2V communications is a key enabler for traffic management and road safety, where vehicles exchange real-time information. Major challenges for practical V2V communications include strict requirements for latency, collision avoidance, throughput, and reliability. This paper proposes a novel scheduling assignment (SA) and data transmission scheme for mode 4-based non-adjacent V2V communications. The main objective of the proposed scheme is to decrease the contention of radio resources to achieve better performance gain. To achieve this, we propose the SA-embedded data message transmission scheme instead of transmitting the SA and data messages separately. To investigate the achievable performance, a mathematical model for the proposed scheme has been derived using the finite state Markov chain. Using this mathematical model, we have derived expressions (validated by simulations) to quantify the collision probability, throughput, transmission probability, and the load on the network. Furthermore, we explore several design parameters and their effects on system performance. Through system level simulation and analytical results, the significant improvement of overall network performance in terms of the throughput maximization and resource collision minimization for the proposed scheme has been shown.
LTE-V2X sidelink/PC5 communication aimed at supporting device-to-device (D2D) communications in vehicular scenario has been developed as an appropriate technology by 3GPP. Particularly, mode 4 operating without cellular coverage permits vehicles autonomously to select resources and has the potential to achieve an efficient and reliable transmission for vehicle safety applications. However, there is very little research conducted on theoretical understanding of the characteristics and performance of mode 4. In this work, we propose a tractable mathematical analysis to evaluate the performance of LTE-V2V in mode 4. Specifically, we assume that vehicles driving on 1-D abstract lane follow a Poisson Point Process (PPP). By means of probability model, we analyze the event that vehicles randomly select the same resource inducing collision, and investigate the failure probability of transmission. Also, the distance between adjacent vehicles is log-normally distributed and the transmission outage probability under a fixed threshold is given. Furthermore, we derive the expression of transmission capacity. To this end, numerical results verify that the transmission capacity of mode 4 can be improved to a certain extent with the increasing of density of vehicles.
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) has recently completed its specifications for connected vehicular (V2X) service. In the mean time, researchers in academia and industry are addressing its security issues involving applications, network and MAC layer protocols. However, the security issue in regard to resource allocation has never been considered until now. Especially in LTE PC5 link, resource allocation with a regular pattern (semi-persistence) to deliver V2X periodic messages may leak the location privacy, even when the other protocol layers are tightly secured. In this proposed work, we provide a secure resource allocation strategy where the vehicular users (VUEs) employ different resource allocation approaches to various types of message deliveries to preserve their privacy. Specifically, the emergency message delivery, being the most time critical and occurring in random time, is provisioned using PC5 autonomous resource allocation (ARA) to protect the privacy. To curtail the collision, we propose a novel ARA approach called Random Access with Status Feedback (RASFB) based on Rel. 12 mode 2. The performance analysis shows the higher performance of the proposed RASFB when compared with the Rel. 12 and Rel. 14 without sacrificing security.
Wireless communication has become a key technology for competitiveness of next generation vehicles. Recently, the 3GPP has initiated standardization activities for LTE-based V2X services composed of vehicle-to-vehicle, vehicle- to-pedestrian, and vehicle-to-infrastructure/network. The goal of these 3GPP activities is to enhance LTE systems to enable vehicles to communicate with other vehicles, pedestrians, and infrastructure in order to exchange messages for aiding in road safety, controlling traffic flow, and providing various traffic notifications. In this article, we provide an overview of the service flow and requirements of the V2X services LTE systems are targeting. This article also discusses the scenarios suitable for operating LTE-based V2X services, and addresses the main challenges of high mobility and densely populated vehicle environments in designing technical solutions to fulfill the requirements of V2X services. Leveraging the spectral-efficient air interface, the cost-effective network deployment, and the versatile nature of supporting different communication types, LTE systems along with proper enhancements can be the key enabler of V2X services.
Vehicle Safety Communications