Jose Leon | RWTH Aachen University (original) (raw)

Papers by Jose Leon

Sensor based automated driving technologies, e.g., Adaptive Cruise Control (ACC), have been devel... more Sensor based automated driving technologies, e.g., Adaptive Cruise Control (ACC), have been developed for many years in order to increase the traffic efficiency. Moreover, in the last decade, there has been a growing interest in further optimizing the traffic efficiency with the help from Vehicle-to- Vehicle (V2V) communications, e.g., Cooperative Adaptive Cruise Control (CACC). This paper investigates the utilization of V2V communication in platooning systems which is one fundamental application in future Intelligent Transport Systems (ITS). A novel V2V assisted platooning system is proposed in this paper, where a proposed prediction based control scheme is used to reduce the required intra-platoon gap under the stability constraint. Moreover, the impact of V2V communications range, delay and reliability on the performance of such platooning systems is dis- cussed. Based on the distributed scheduling scheme in 3GPP Rel. 14 LTE-V2X sidelink (SL), a platoon based scheduling scheme is proposed to increase the intra-platoon V2V communication reliability.

In this paper, the mobile radio propagation channel models, obtained from software simulation and... more In this paper, the mobile radio propagation channel models, obtained from software simulation and real world measurements in a multiple-input multiple-output (MIMO) system of an urban scenario (Ilmenau City) have been investigated. Our interest consists of proving the validity of the simulation model obtained, comparing the different approaches. For the comparison, the PIROPA (Parallel Implemented Ray Optical Propagation Algorithm) software and the WINNER II (Wireless world INitiative NEw Radio II) channel model have been used. The mathematical back- ground used is the double-directional radio channel based on the on-site data. The special importance of this approach is, that not only the pathloss of the link is considered, but also the angle of departure and angle of arrival into the transmitter and receiver, are taken into account, respectively.

A novel hybrid environment-based approach for modeling the vehicular communication channel is dev... more A novel hybrid environment-based approach for modeling the vehicular communication channel is developed in this study. It is a combination of a deterministic ray-launching algorithm (PIROPA) to model the Large-Scale parameters, and a stochastic model, to obtain the Small-Scale parameters. This hybrid channel model is site-dependent, i.e., the propagation parameters of the channel are obtained based on the particular scenario, giving a higher accuracy in modeling the channel than using an abstract representation of the scenario. The use of a stochastic approach also provides the model of a flexibility re- quired for different scenario situations, specially in a dynamic en- vironment like vehicular communications. The simulation results show the significance of the scenario and how the peculiarities of the vehicular communications, i.e., low antenna height and high mobility of the receivers and transmitters, impact on the communication channel. The proposed channel model can be used for different applications, such as anti-collision systems, autonomous driving or video applications.

ehicular communications are increasingly gaining importance in research and industry as a viable ... more ehicular communications are increasingly gaining importance in research and industry as a viable communication technology, which makes cost-efficient and reliable deployment strategies a key aspect for the planning of a communication network infrastructure. The most critical aspect, and at the same time, the biggest challenge is to obtain a total connectivity between the vehicles and the network elements. In this paper, an environment-based deployment strategy is developed, obtaining an optimal number and distribution of RSUs in a selected area while maximizing the connectivity of the network. The main distinctive aspect of the proposed strategy is the use of an environment-based radio channel model, which is specific for a given urban area. Once the site-specific propagation parameters of the proposed radio channel model are obtained, the optimal RSU distribution is achieved by solving a multi-objective, integer linear program. In addition, a metaheuristic algorithm based on tabu-search is proposed for the solution. The network optimization scheme suggested in this work shows an enhanced coverage granting an always on connectivity for vehicle-to-infrastructure networks. Furthermore, due to the optimal number of RSUs, the cost of the network is minimized, which makes the deployment strategy feasible for real scenarios.

The paper proposes vehicular communication principles in order to increase workers and pedestrian... more The paper proposes vehicular communication principles in order to increase workers and pedestrians cross- roads safety at the seaport. A hybrid environment-based approach for modeling the vehicular communication channel is used. It is based on a combination of a deterministic ray- launching algorithm (PIROPA) to model large-scale parameters, and a stochastic model to obtain small-scale ones. Simulation analysis of some power-delay profiles for different workers or pedestrians and front forklifts seaport cross-roads interplays are done over the selected container and general cargo terminal area of the Port of Bar (Montenegro). The results provide good understanding of the communication requirements in order to obtain a feasible on-post safety system.

In this paper, an optimized cooperative commu- nication scheme based on the recently presented LT... more In this paper, an optimized cooperative commu- nication scheme based on the recently presented LTE-V2X is introduced. LTE-V2X is the newly proposed technology by 3GPP in its Release 14 in order to obtain a feasible communication scheme between vehicles and infrastructures. This paper inves- tigates the case of centralized network architecture, where the eNodeBs are used as information centers in order to optimize the scheduling scheme by means of clustering the vehicles in their coverage range. The proposed cooperative scheme is based on the shared messages between vehicles using a semi-persistent scheduling (SPS) which fulfills the rigid requirements, i.e., delay and reliability, faced in vehicular communications. In this paper, an enhancement of the SPS is defined using the information gathered by the network infrastructures in order to mitigate the interference. In addition, due to the high mobility of the vehicles, a predictive control model is implemented to estimate the vehicles trajectory, hence, improving the scheduling scheme performance. The aforementioned methods are simulated in a realistic scenario, using a traffic simulator, and compared with the standard LTE- V2X implementation as well as other methods proposed in the literature.

The wireless channel in mobile communications changes the transmitted signal and thus must be pro... more The wireless channel in mobile communications changes the transmitted signal and thus must be properly modeled. If a multiple-input multiple-output (MIMO) system is considered, the modeling procedure becomes more challenging. In this paper, a novel radio channel model is implemented and validated using measurement data. On one hand, statistical properties of MIMO channels are modeled by geometry-based stochastic models, such as the WINNER II model. On the other hand, the physical phenomena of radio wave propagation can be described by deterministic methods, such as PIROPA (parallel implemented ray optical propagation algorithm). Additionally, the proposed channel model can be derived by combining the stochastic model and physical model. The results show that the proposed channel model has advantages in modeling accuracy and execution time over the WINNER II model.

A two-level cooperative network scheme for vehicular communications is proposed in this paper. Th... more A two-level cooperative network scheme for vehicular communications is proposed in this paper. The network architecture consists on a set of deployed RoadSide Units (RSU) based on the expected density of nodes in the network whereas these nodes are organized as a vehicular ad- hoc network. The position of the RSUs is obtained using the k- means algorithm along with the gap statistic to obtain the optimal number of base stations. The nodes are clustered using spectral clustering based on the geographical position and dynamics of each node, subject to their predictable and highly correlated behavior with the environment. The head-cluster is chosen using concepts of coalitional games in order to extend the stability of the cluster. Additionally, using the beacons sent by the head-cluster to the RSU, a prediction in the dynamic behavior of the clustered nodes is achieved. The RSUs are interconnected using LTE links to provide a cooperative scheme, granting an optimal selection of the head-cluster, and prolonging its lifetime. Finally, the proposed two-level network scheme along with the clustering prediction method are analyzed and compared with the commonly used clustering techniques in a real scenario. The simulation results show the positive impact of the cooperative scheme developed predicting the movement of the clusters.

This paper introduces a multi-level cooperative scheme for autonomous vehicles, using the sensors... more This paper introduces a multi-level cooperative scheme for autonomous vehicles, using the sensors equipped on- board and a communication scheme with the deployed infrastructures. The proposed model focuses on the communication elements, delving into the cooperative aspect between the network components. The first level of the proposed scheme is composed of a multi-sensor data fusion framework using the measurements obtained from the vehicle on-board sensors, in order to detect obstacles in front of the vehicle. The obstacle detection is based on a liner regression fusion rule, which combines the obtained features from several sensors. Once the decision is taken, the vehicle responds consequently using implicit coordination and bringing the network to an uncertain status. Hence, the second level consists on achieving a stable network by applying explicit coordination between the vehicles and the deployed infrastructures. The third level controls the entire network from a centralized perspective using long-range communication links. Using the knowledge obtained from the centralized network, optimization can be achieved using a coordination scheme based on communication. To finalize, the theoretical framework is simulated under realistic conditions obtaining promising results, in terms of obstacle avoidance and network coordination.

Sensor based automated driving technologies, e.g., Adaptive Cruise Control (ACC), have been devel... more Sensor based automated driving technologies, e.g., Adaptive Cruise Control (ACC), have been developed for many years in order to increase the traffic efficiency. Moreover, in the last decade, there has been a growing interest in further optimizing the traffic efficiency with the help from Vehicle-to- Vehicle (V2V) communications, e.g., Cooperative Adaptive Cruise Control (CACC). This paper investigates the utilization of V2V communication in platooning systems which is one fundamental application in future Intelligent Transport Systems (ITS). A novel V2V assisted platooning system is proposed in this paper, where a proposed prediction based control scheme is used to reduce the required intra-platoon gap under the stability constraint. Moreover, the impact of V2V communications range, delay and reliability on the performance of such platooning systems is dis- cussed. Based on the distributed scheduling scheme in 3GPP Rel. 14 LTE-V2X sidelink (SL), a platoon based scheduling scheme is proposed to increase the intra-platoon V2V communication reliability.

In this paper, the mobile radio propagation channel models, obtained from software simulation and... more In this paper, the mobile radio propagation channel models, obtained from software simulation and real world measurements in a multiple-input multiple-output (MIMO) system of an urban scenario (Ilmenau City) have been investigated. Our interest consists of proving the validity of the simulation model obtained, comparing the different approaches. For the comparison, the PIROPA (Parallel Implemented Ray Optical Propagation Algorithm) software and the WINNER II (Wireless world INitiative NEw Radio II) channel model have been used. The mathematical back- ground used is the double-directional radio channel based on the on-site data. The special importance of this approach is, that not only the pathloss of the link is considered, but also the angle of departure and angle of arrival into the transmitter and receiver, are taken into account, respectively.

A novel hybrid environment-based approach for modeling the vehicular communication channel is dev... more A novel hybrid environment-based approach for modeling the vehicular communication channel is developed in this study. It is a combination of a deterministic ray-launching algorithm (PIROPA) to model the Large-Scale parameters, and a stochastic model, to obtain the Small-Scale parameters. This hybrid channel model is site-dependent, i.e., the propagation parameters of the channel are obtained based on the particular scenario, giving a higher accuracy in modeling the channel than using an abstract representation of the scenario. The use of a stochastic approach also provides the model of a flexibility re- quired for different scenario situations, specially in a dynamic en- vironment like vehicular communications. The simulation results show the significance of the scenario and how the peculiarities of the vehicular communications, i.e., low antenna height and high mobility of the receivers and transmitters, impact on the communication channel. The proposed channel model can be used for different applications, such as anti-collision systems, autonomous driving or video applications.

ehicular communications are increasingly gaining importance in research and industry as a viable ... more ehicular communications are increasingly gaining importance in research and industry as a viable communication technology, which makes cost-efficient and reliable deployment strategies a key aspect for the planning of a communication network infrastructure. The most critical aspect, and at the same time, the biggest challenge is to obtain a total connectivity between the vehicles and the network elements. In this paper, an environment-based deployment strategy is developed, obtaining an optimal number and distribution of RSUs in a selected area while maximizing the connectivity of the network. The main distinctive aspect of the proposed strategy is the use of an environment-based radio channel model, which is specific for a given urban area. Once the site-specific propagation parameters of the proposed radio channel model are obtained, the optimal RSU distribution is achieved by solving a multi-objective, integer linear program. In addition, a metaheuristic algorithm based on tabu-search is proposed for the solution. The network optimization scheme suggested in this work shows an enhanced coverage granting an always on connectivity for vehicle-to-infrastructure networks. Furthermore, due to the optimal number of RSUs, the cost of the network is minimized, which makes the deployment strategy feasible for real scenarios.

The paper proposes vehicular communication principles in order to increase workers and pedestrian... more The paper proposes vehicular communication principles in order to increase workers and pedestrians cross- roads safety at the seaport. A hybrid environment-based approach for modeling the vehicular communication channel is used. It is based on a combination of a deterministic ray- launching algorithm (PIROPA) to model large-scale parameters, and a stochastic model to obtain small-scale ones. Simulation analysis of some power-delay profiles for different workers or pedestrians and front forklifts seaport cross-roads interplays are done over the selected container and general cargo terminal area of the Port of Bar (Montenegro). The results provide good understanding of the communication requirements in order to obtain a feasible on-post safety system.

In this paper, an optimized cooperative commu- nication scheme based on the recently presented LT... more In this paper, an optimized cooperative commu- nication scheme based on the recently presented LTE-V2X is introduced. LTE-V2X is the newly proposed technology by 3GPP in its Release 14 in order to obtain a feasible communication scheme between vehicles and infrastructures. This paper inves- tigates the case of centralized network architecture, where the eNodeBs are used as information centers in order to optimize the scheduling scheme by means of clustering the vehicles in their coverage range. The proposed cooperative scheme is based on the shared messages between vehicles using a semi-persistent scheduling (SPS) which fulfills the rigid requirements, i.e., delay and reliability, faced in vehicular communications. In this paper, an enhancement of the SPS is defined using the information gathered by the network infrastructures in order to mitigate the interference. In addition, due to the high mobility of the vehicles, a predictive control model is implemented to estimate the vehicles trajectory, hence, improving the scheduling scheme performance. The aforementioned methods are simulated in a realistic scenario, using a traffic simulator, and compared with the standard LTE- V2X implementation as well as other methods proposed in the literature.

The wireless channel in mobile communications changes the transmitted signal and thus must be pro... more The wireless channel in mobile communications changes the transmitted signal and thus must be properly modeled. If a multiple-input multiple-output (MIMO) system is considered, the modeling procedure becomes more challenging. In this paper, a novel radio channel model is implemented and validated using measurement data. On one hand, statistical properties of MIMO channels are modeled by geometry-based stochastic models, such as the WINNER II model. On the other hand, the physical phenomena of radio wave propagation can be described by deterministic methods, such as PIROPA (parallel implemented ray optical propagation algorithm). Additionally, the proposed channel model can be derived by combining the stochastic model and physical model. The results show that the proposed channel model has advantages in modeling accuracy and execution time over the WINNER II model.

A two-level cooperative network scheme for vehicular communications is proposed in this paper. Th... more A two-level cooperative network scheme for vehicular communications is proposed in this paper. The network architecture consists on a set of deployed RoadSide Units (RSU) based on the expected density of nodes in the network whereas these nodes are organized as a vehicular ad- hoc network. The position of the RSUs is obtained using the k- means algorithm along with the gap statistic to obtain the optimal number of base stations. The nodes are clustered using spectral clustering based on the geographical position and dynamics of each node, subject to their predictable and highly correlated behavior with the environment. The head-cluster is chosen using concepts of coalitional games in order to extend the stability of the cluster. Additionally, using the beacons sent by the head-cluster to the RSU, a prediction in the dynamic behavior of the clustered nodes is achieved. The RSUs are interconnected using LTE links to provide a cooperative scheme, granting an optimal selection of the head-cluster, and prolonging its lifetime. Finally, the proposed two-level network scheme along with the clustering prediction method are analyzed and compared with the commonly used clustering techniques in a real scenario. The simulation results show the positive impact of the cooperative scheme developed predicting the movement of the clusters.

This paper introduces a multi-level cooperative scheme for autonomous vehicles, using the sensors... more This paper introduces a multi-level cooperative scheme for autonomous vehicles, using the sensors equipped on- board and a communication scheme with the deployed infrastructures. The proposed model focuses on the communication elements, delving into the cooperative aspect between the network components. The first level of the proposed scheme is composed of a multi-sensor data fusion framework using the measurements obtained from the vehicle on-board sensors, in order to detect obstacles in front of the vehicle. The obstacle detection is based on a liner regression fusion rule, which combines the obtained features from several sensors. Once the decision is taken, the vehicle responds consequently using implicit coordination and bringing the network to an uncertain status. Hence, the second level consists on achieving a stable network by applying explicit coordination between the vehicles and the deployed infrastructures. The third level controls the entire network from a centralized perspective using long-range communication links. Using the knowledge obtained from the centralized network, optimization can be achieved using a coordination scheme based on communication. To finalize, the theoretical framework is simulated under realistic conditions obtaining promising results, in terms of obstacle avoidance and network coordination.