• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.4
• /
• pp.62-77
• /
• 2022

A cooperative driving automation system is imperative to overcome the limitation of the stand-alone automated driving technology. By definition, a cooperative driving automation system refers to a technology in which an automated vehicle cooperates with other vehicles or infrastructure to increase driving efficiency and safety. Specifically, in this study, the technical elements necessary for the cooperative driving automation technology and the technological research trends were investigated. Subsequently, implications for future cooperative driving automation technology development were drawn through the research trends. Finally, the importance of cooperative driving automation technology and infra-guidance service for automated vehicles were discussed.

• Journal of Advanced Navigation Technology
• /
• v.23 no.6
• /
• pp.515-521
• /
• 2019

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the global navigation satellite system. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In addition, performance analysis must be performed according to various environments that change according to traffic or road conditions in a dynamic environment. In this paper, we describe with the performance of traffic and road environment through the evaluation system of lane positioning precision positioning user system based on satellite navigation system. The numerical performance evaluation was carried out based on the data collected by carrying out the actual driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse evaluation results of positioning performance according to driving condition.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.3
• /
• pp.51-58
• /
• 2010

According to dramatic increase of wireless communication demand, more spectrum resources are needed to support considerable and various wireless services, so cognitive radio(CR) was proposed to reuse unused frequency efficiently. Also, FCC revises its policies regarding the usage of the TV white spaces by unlicensed users. CR is an intelligent wireless communication system that is aware of the radio environment and is capable of adapting its operation to the statistical variations. Spectrum sensing is the key task of the CR systems. However, since spectrum sensing performance changes according to the received signal that is received various geography environment, regional characteristics are considered to estimate the path-loss. Therefore, for more accurate analysis and simulation, we demonstrate the spectrum sensing performance of CR system by various method applying Okumura-hata propagation model.

• The KIPS Transactions:PartC
• /
• v.17C no.3
• /
• pp.243-250
• /
• 2010

Vehicular communication networking is one of the most important building blocks of Intelligent Transportation System (ITS). The vehicular communication network is a wireless communication system enabling vehicles to communicate with each other as well as with roadside base stations. Mobility management of vehicles which move at high speeds and occasionally make a long journey is an interesting research area of vehicular communication networks. Recently, The Proxy Mobile IPv6 (PMIPv6) protocol is proposed for network-based mobility management to reduce the overhead of mobile nodes. PMIPv6 shifts the burden of the mobility management from mobile nodes to network agents to decrease the overhead and latency for the mobility management. In this paper, we derive the scenario of deploying PMIPv6 in vehicular communication networks and propose a new LMA handover mechanism for realizing the scenario. By carrying out the ns-2 based simulations, we verify the operability of the proposed mechanism.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.566-576
• /
• 2018

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the GNSS. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In this paper, we selected performance indicators, assessment equipment, and reliability of reference equipment for evaluation of precision positioning user systems based on the GNSS. The performance evaluation system described above is applied to a real system, and the performance evaluation tool developed for the evaluation system is described. The numerical performance evaluation was carried out based on the data collected by carrying out the actual testbed driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse the evaluation results of the vehicle lane level positioning user system.

• Journal of Internet Computing and Services
• /
• v.17 no.6
• /
• pp.81-91
• /
• 2016

VANET is one of the most developed technologies many people have considered a technology for the next generation. It basically utilizes the wireless technology and it can be used for measuring the speed of the vehicle, the location and even traffic control. With sharing those information, VANET can offer Cooperative ITS which can make a solution for a variety of traffic issues. In this way, safety for drivers, efficiency and mobility can be increased with VANET but data between vehicles or between vehicle and infrastructure are included with private information. Therefore alternatives are necessary to secure privacy. If there is no alternative for privacy, it can not only cause some problems about identification information but also it allows attackers to get location tracking and makes a target. Besides, people's lives or property can be dangerous because of sending wrong information or forgery. In addition to this, it is possible to be information stealing by attacker's impersonation or private information exposure through eavesdropping in communication environment. Therefore, in this paper we propose Privacy Assurance Architecture for VANET to ensure privacy from these threats.

• Journal of Advanced Navigation Technology
• /
• v.10 no.4
• /
• pp.394-399
• /
• 2006

In this paper, we investigated performance for 5.8GHz dedicated short range communication system using OFDM which will be applied to Intelligent transportation system services. The maximum speed of a vehicle in DSRC channel is very fast as 180km/h, so a service time is very short to serve a various traffic information if hand-off is not occurred. Therefore higher bit rate is required to proved advanced and intelligent service to the drivers of various vehicle and the data transmission rate of the next generation DSRC system if being promoted over 10Mbps. The signals received in Clarke & Gans channel have been simulated using the computer simulator.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.06d
• /
• pp.316-318
• /
• 2006

본 논문에서는 차세대 지능형 교통시스템인 UTIS(Urban Traffic Information System)의 빠른 접속 요구 조건을 만족하기 위한 DLC(Dynamic Limited Contention) 알고리즘을 제안한다. UTIS 네트워크는 고속으로 이동하는 차량에 설치된 모바일 노드와 도로 변에 설치된 노변 기지국으로 구성되며, 이 네트워크를 통해서 IP 데이터 그램의 전송 서비스, 방송 데이터를 실시간으로 전송하는 실시간 전송 서비스 그리고 차량의 위치를 계속적으로 알려 주는 위치 탐색 서비스를 지원한다. 이러한 전송 서비스를 지원하기 위해서 UTIS는 물리 계층과 MAC 계층으로 구성된다. 그러나 UTIS에서는 차량의 고속 이동으로 인해서 셀(cell)간의 핸드오프가 빈번히 발생하고 또한 위치 추적과 방송 서비스와 같은 실시간 전송 서비스를 지원해야 하기 때문에 기존의 802.11 MAC을 사용할 수 없다. 즉 UTIS에서의 빠른 등록 요구 조건을 충족시키기 위해 기존의 802.11에서 사용하는 경쟁(contention) 방식은 비효율적이다. 본 논문에서는 셀 내에 도착하는 노드 수에 따라 경쟁을 하는 그룹의 크기를 동적으로 조절하는 DLC 알고리즘을 제안한다. 기존의 UTIS에서는 그룹 크기를 정적으로 결정하고 모바일 노드는 자신의 주소에 이 정적 그룹 크기로 modulo하여 자신의 속한 그룹을 초기에 계산한다. 기지국이 접속해야하는 그룹을 폴링 메시지로 지정할 때 그 그룹에 속한 모바일 노드들만이 제한적으로 경쟁하게 된다. 이러한 정적인 그룹 크기는 셀 내에의 노드의 숫자와 그룹 크기의 분포를 고려하지 않는 방식으로 비효율적이다. 본 DLC 알고리즘에서는 전 폴링 주기 동안에 경쟁하는 노드의 빈도수를 계속적으로 추적하여 등록 시점에 경쟁하는 그룹의 개수를 동적으로 조절하게 된다. 이러한 방식은 UTIS와 같이 접속 시간이 제한적이고 접속하려는 노드 수가 빠르게 변화하는 환경 하에서 기존의 802.11 MAC 프로토콜과 정적인 그룹 크기 방식에 비해 효율적이다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.12
• /
• pp.1950-1958
• /
• 2016

Today, technique for precisely positioning vehicles is very important in C-ITS(Cooperative Intelligent Transport System), Self-Driving Car and other information technology relating to transportation. Though the most popular technology for vehicle positioning is the GPS, its accuracy is not reliable because of large delay caused by multipath effect, which is very bad for realtime traffic application. Therefore, in this paper, we proposed the Vision-Based High Accuracy Vehicle Positioning Technology. At the first step of proposed algorithm, the ROI is set up for road area and the vehicles detection. Then, center and four corners points of found vehicles on the road are determined. Lastly, these points are converted into aerial view map using homography matrix. By analyzing performance of algorithm, we find out that this technique has high accuracy with average error of result is less than about 20cm and the maximum value is not exceed 44.72cm. In addition, it is confirmed that the process of this algorithm is fast enough for real-time positioning at the $22-25_{FPS}$.

• Journal of Intelligence and Information Systems
• /
• v.22 no.1
• /
• pp.107-118
• /
• 2016

The advent of 5G mobile communications, which is expected in 2020, will provide many services such as Internet of Things (IoT) and vehicle-to-infra/vehicle/nomadic (V2X) communication. There are many requirements to realizing these services: reduced latency, high data rate and reliability, and real-time service. In particular, a high level of reliability and delay sensitivity with an increased data rate are very important for M2M, IoT, and Factory 4.0. Around the world, 5G standardization organizations have considered these services and grouped them to finally derive the technical requirements and service scenarios. The first scenario is broadcast services that use a high data rate for multiple cases of sporting events or emergencies. The second scenario is as support for e-Health, car reliability, etc.; the third scenario is related to VR games with delay sensitivity and real-time techniques. Recently, these groups have been forming agreements on the requirements for such scenarios and the target level. Various techniques are being studied to satisfy such requirements and are being discussed in the context of software-defined networking (SDN) as the next-generation network architecture. SDN is being used to standardize ONF and basically refers to a structure that separates signals for the control plane from the packets for the data plane. One of the best examples for low latency and high reliability is an intelligent traffic system (ITS) using V2X. Because a car passes a small cell of the 5G network very rapidly, the messages to be delivered in the event of an emergency have to be transported in a very short time. This is a typical example requiring high delay sensitivity. 5G has to support a high reliability and delay sensitivity requirements for V2X in the field of traffic control. For these reasons, V2X is a major application of critical delay. V2X (vehicle-to-infra/vehicle/nomadic) represents all types of communication methods applicable to road and vehicles. It refers to a connected or networked vehicle. V2X can be divided into three kinds of communications. First is the communication between a vehicle and infrastructure (vehicle-to-infrastructure; V2I). Second is the communication between a vehicle and another vehicle (vehicle-to-vehicle; V2V). Third is the communication between a vehicle and mobile equipment (vehicle-to-nomadic devices; V2N). This will be added in the future in various fields. Because the SDN structure is under consideration as the next-generation network architecture, the SDN architecture is significant. However, the centralized architecture of SDN can be considered as an unfavorable structure for delay-sensitive services because a centralized architecture is needed to communicate with many nodes and provide processing power. Therefore, in the case of emergency V2X communications, delay-related control functions require a tree supporting structure. For such a scenario, the architecture of the network processing the vehicle information is a major variable affecting delay. Because it is difficult to meet the desired level of delay sensitivity with a typical fully centralized SDN structure, research on the optimal size of an SDN for processing information is needed. This study examined the SDN architecture considering the V2X emergency delay requirements of a 5G network in the worst-case scenario and performed a system-level simulation on the speed of the car, radius, and cell tier to derive a range of cells for information transfer in SDN network. In the simulation, because 5G provides a sufficiently high data rate, the information for neighboring vehicle support to the car was assumed to be without errors. Furthermore, the 5G small cell was assumed to have a cell radius of 50-100 m, and the maximum speed of the vehicle was considered to be 30-200 km/h in order to examine the network architecture to minimize the delay.