Dynamical route-planning for vehicles based on global traffic information and communication

We propose a new way to disperse planning route of transportation using IVC (Inter Vehicle Communication) in this paper. VICS (Vehicle Information and Communication System) has been developed to solve the traffic jam which is one of the ITS (Intelligent Transportation Systems) technologies. The VlCS is able to provide real-time global information with drivers and navigation system which helps drivers to find the fastest route according to the current traffic conditions. However, it is afraid that spatial oscillation of traffic jam "hunting phenomena" will happen if most of cars follow given global information with time delay from VICS. 0n the other hand, IVC is a developing technology which enables cars to exchange various information with others by optical communication, millimeter electromagnetic waves and so on. We therefore propose the combination way to decrease traffic congestion using IVC and VICS. At first we show the hunting phenomena in numerical simulations and the relationship between hunting phenomena and VICS user ratio. We propose a way to disperse planning route by IVC, and then confirm effect of the proposed way in city traffic models in numerical simulations.

The traffic congestion frequently occurs in urban transportations. In order to alleviate the traffic congestion, the vehicle information and communication system (VICS) has been developed. However, since each vehicle can obtain global information on traffic congestion using VICS, all vehicles in the congested areas tend to move to non-congested areas. As a result, the non-congested areas become congested areas. To avoid such the oscillation between the congested and non-congested areas, this paper proposes a novel method based on the vehicle ad hoc network (VANET) for alleviating traffic congestion in urban transportations. In the proposed method, since each vehicle independently collects local information on traffic congestion using VANET, traffic can be distributed from congested areas to non-congested areas. Through simulation experiments, this paper shows that the proposed method provides faster velocity and shorter trip time than VICS in the environments that traffic varies temporally and spatially, which occur in urban transportations.

A radio over dense-wavelength-division-multiplexing (DWDM) transport system for personal handy system (PHS)/vehicle information and communication system (VICS)/electronic toll collection (ETC)/satellite broadcasting (SB) applications was proposed and demonstrated. Improved performance of bit error rate (BER) over a-100 km of large effective area fiber (LEAF) was obtained. Signal qualities meet the PHS demand with a data signal of 1.9 GHz/10 Mbps, VICS demand with a data signal of 2.5 GHz/12 Mbps, ETC demand with a data signal of 5.8 GHz/20 Mbps, and SB demand with a data signal of 12 GHz/25 Mbps.

The Radio Beacon System provides digital radio transmissions as part of the Vehicle Information and Communication System (VICS). Operating in the quasi-microwave (2.5 GHz) band at transmission speeds of 64 kbps, the system enables moving vehicles to be provided with roadway-traffic and location information. According to available reports on tests of this system, a service area of 70 m or more can be secured along open roadways where road station antennas are installed. Since the Metropolitan Expressway Public Corporation plans to construct a number of tunnels in the future, any practical Radio Beacon System will require that road stations also be located in tunnels. To confirm the possibility of communication in tunnels, the authors conducted an in-tunnel-evaluation test of the system to clarify in-tunnel transmission characteristics, which seem likely to be quite different from those on open roadways. >

This paper describes an exact solution approach for the Vehicle Routing and scheduling Problem with Soft Time Windows (VRPSTW), and presents its application on a realistic logistics instance based on the VICS (Vehicle Information and Communication System) data, an ITS application in Japan. Exact solutions of VRPSTW have been compared with those of the Vehicle Routing and scheduling with Hard Time Windows (VRPHTW). Detailed analysis of environmental issues and idling time along with the traditional comparison of cost and number of vehicles, shows that the exact VRPSTW solutions are not only cost efficient but helpful in reducing congestion, which implies these are more environmentally sustainable.

Dedicated short range communication (DSRC) in the 5.9 GHz band has been considered as the main inter- vehicle communication (IVC) method in the past. Recently, IVC by cellular V2X (LTE support for V2X services) has attracted much attention, which includes two schemes: sidelink by which vehicles communicate directly with each other and broadcast via eNodeB for dissemination to farther vehicles. In this paper, we will show that none of these methods alone can fulfill the reliable and low delay communication, and investigate a basic method that combines DSRC for fast dissemination in a short distance and cellular V2X (broadcast via eNodeB) for reliable dissemination in a wide range. We notice that vehicles near the same event (e.g., falling object) may repeatedly disseminate the same message and some messages may be disseminated beyond their required range, which degrade network performance. Therefore, we further improve the efficiency of the basic method from two aspects: (i) dissemination range control that constrains the dissemination of each message within its required range, and (ii) duplicate dissemination control that avoids disseminating the message containing the same information in the network. Simulations on network simulator with LTE release-14 confirm that the method combining DSRC and cellular V2X reduces the delay by up to 66% compared to the method using only cellular V2X, and the extended method further improves the reachability by up to 15%.

We examine the performance of inter-vehicle communication (IVC) systems using the IEEE802.11b standard CSMA scheme and a proposed system in which packet transmission timing is decided by the vehicle position. For the realization of safety cruise-assist systems by IVC systems, the spread of transceivers on vehicles is important. To improve the equipped rate of transceivers on vehicles, it is necessary that the implementation of more simple and cheaper IVC systems. One of the solutions is using conventional wireless LAN systems for IVC systems. So we evaluate the performance of an IVC system using the conventional IEEE802.11b CSMA system. In addition, we propose and evaluate an improvement scheme for solving the performance degradation caused by packet collision. The results of simulation show that the proposed scheme is superior to other schemes when the bit rate is low. Also, it is shown that the proposed scheme has the same or higher performance than the other schemes in high bit rate.

An optimal global algorithm for route guidance in advanced traveler information systems

We developed the WACNet (wireless ad hoc community network) test system based on IEEE 802.11g and ESPAR antenna. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets at the communication situation (Tx and Rx). We can choose the data transmission rate to be adaptive or fixed among the duration through 54 Mbps to 1 Mbps for the purpose of experiment. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to improve total throughput, total error rate and so on rather than the original protocol. In this paper, we show the structure and wireless communication characteristics and the performance of video streaming at multihop communication with camera and codec connected to WACNet test system on the mobile experimental cars for ITS inter vehicle communications

Many capital cities in the world encounter the similar problem of traffic jam due to the population growth and the need for transportation. Bangkok, Thailand is one of the top cities with serious traffic jam. An inter vehicle communication was proposed to provide the real time road information to realize the intelligent transportation system (ITS) with the hope to mitigate the serious traffic jam [1]. Several have proposed solutions for inter-vehicle communication using infrared (IR) Bluetooth, Wi-Fi and Wi-Max. In this paper we study the performance of Wi-Fi and Zigbee networks for inter-vehicle communication in Bangkok area using network simulation, ns-2. Our study is aimed to understand the effect of the number of installed road side stations to network performance. The study has shown that Wi-Fi network yields the higher successful rate and the shorter delay than that of Zigbee. From our results, the optimal number of installed road side stations in the case of WLAN is about 9 stations per sq. km. and this provides the successful transmission rate of 55%. In the case of using Zigbee networks, about 10 stations per sq. km. is needed with the condition that the vehicle density is at least 12 cars per sq. km. to provide the successful rate of 8%.

This paper discusses the IVC (Inter Vehicle Communication) system using the UWB (Ultra Wideband) radar. DSUWB (Direct Sequence - UWB) signal is used for this IVC system because it has CDMA (Code Division Multiple Access) Capability. However, there is the near-far problem due to difference of signal power from each vehicles, it becomes the cause of degradation of communication characteristics and detection accuracy of the signal. In this paper, we propose the iterative detection system using the SIC (Successive Interference Cancellation) to improve detection rate of the signal and the bit error rate (BER) performance. The signals except the desired signal detected by the SIC is subtracted from the original received signal. As the result, the performance was improved.

Networking methods and applications of the inter-vehicle packet communication system are discussed. In a proposed system, vehicles and roadside beacons broadcast individual ID, position, speed in a cyclic manner using time-dots allocated with a distributed algorithm. Other information is transmitted with the random access. The routing method using 1-hop cyclic information is applied to relay the information packet to farther terminals efficiently. This communication system is extensible and realize its applications efficiently. As a new remarkable application of the inter-vehicle communication system, we propose the drive control of vehicles. >

Future Multiprocessor Systems-on-Chip (SoCs) will consist of various digital and analog components, such as processing cores, storage elements, customized IP-cores, analog peripheral devices, and many other items of MEMS. Network-on-chip is a promising mechanism which provides a power- and performance-efficient communication infrastructure for such complex on-chip systems. This paper presents a routing algorithm to cope with the dynamic traffic pattern of network-on-chip (NoC) architectures aiming to distribute the on-chip traffic evenly across the network. In this algorithm, instead of relying solely on local congestion information, the routes are determined based on the global traffic information. This is achieved by employing a light-weight and efficient control network which monitors the on-chip traffic and collects the required global information for determining the appropriate paths between any pairs of communicating nodes in such a way that the congestion is avoided and the NoC load is balanced. Our experiments show that the proposed method outperforms the conventional deterministic and adaptive routing mechanisms under some benchmarks running on a 7×7 NoC.

A novel collaborative strategy employing two relays is developed for the multihop inter-vehicle communication (IVC) systems in this paper, which has great complexity degradation. Instead of the traditional terminal collaboration or relay tier space-time coding (STC), a relay tier interaction is proposed. Considering time division multiple access (TDMA) scheme, two spatial adjacent vehicles are conjoined by an interaction radio link to create a virtual antenna array (VAA). Then the collaborative two-relay is integrated into a multihop IVC network mentioned above, which enables a single-antenna terminal to share its antenna with other terminals easily, and avoids the synchronization or other complicated requirements in terminal collaboration or STC systems. Furthermore, except the low complexity in hardware implementation, the proposed method also can enhance the performance of the IVC systems over both the quasi-static fading channel and time varying Rayleigh fading relay channel, which is verified through the Monte-Carlo simulations

Reliability is one of the key requirements for inter-vehicle communication in order to improve safety in road traffic. This paper describes the difficulties of inter-vehicle communication. We focus on an analysis of the state-of-the art MAC protocol draft IEEE P802.11p and its limitations in high load situations. For our analysis we consider a particular safety scenario: An emergency vehicle is approaching a traffic jam. In a simulation experiment, we highlight that severe packet loss can occur. The reliable transmission range can be reduced by up to 90%. The main reason for this degradation is interference caused by transmissions of other vehicles within the traffic jam. In the study, we focus on the vehicle at the very end of the traffic jam. There, we measure the number of packets per second that are successfully received from the emergency vehicle. The key observation is that only a small fraction of the warning lead time remains which will also reduce the time for the driver to react on this information on an approaching emergency vehicle.