M. Aoki

Bio: M. Aoki is an academic researcher from Seikei University. The author has contributed to research in topics: Communications system & Communications protocol. The author has an hindex of 1, co-authored 1 publications receiving 95 citations.

Inter-vehicle communication: technical issues on vehicle control application

Abstract: Mutual exchange of status data between vehicles in close proximity is the basis for safe vehicle operation. Application areas range from driver assistance/warning to fully autonomous driving. To enable this data exchange we need an intervehicle communication (IVC) system. Vehicles involved in mutual data exchange form a kind of local area network; however, the characteristics of this network are quite different from those of conventional networks. The configuration of this kind of network changes from time to time, in terms of organization, proximity group, group position, and relative position; therefore, it is very challenging to establish. The authors have been working on this problem from the point of view of communication media and protocol. The characteristics and requirements of IVC are discussed, and several preliminary communication protocols are proposed. The authors also present some experimental results from the implementation of a function integrating communication by infrared ray with a gap-measuring technique by the vision system.

Disseminating messages among highly mobile hosts based on inter-vehicle communication

Abstract: We present an approach to distributing messages among highly mobile hosts in ad hoc networks. We focus on using direct radio communication between moving vehicles on the road that requires no additional infrastructure. Thus, the vehicles need to organize access to the radio channel in a decentralized manner. We derive the medium access control from the standard IEEE 802.11. Also, the vehicles use omnidirectional antennas implying that a sender can transit to multiple hosts simultaneously. As an example, we study a road accident that is reported to nearby vehicles. Simulations show that the quality of the proposed protocol by measuring how many vehicles inside a zone-of-relevance are informed under various conditions.

Automotive telemetry protocol

Abstract: Disclosed is a method of conveying vehicle operation data from a vehicle to a remote monitoring recipient, comprising the steps of establishing a data link between the vehicle and the remote monitoring recipient; collecting vehicle operation data from data sources in the vehicle; packaging the vehicle operation data in a data packet using protocol derived from SNMP; and conveying the data packet over the data link.

Role-based multicast in highly mobile but sparsely connected ad hoc networks

Abstract: We present an approach to multicasting messages among highly mobile hosts in ad hoc networks. We suggest a new definition of a role-based multicast that suits the special needs of inter-vehicle communication: rather than by explicit identification, a multicast group is defined implicitly by location, speed, driving direction and time. As an example, we study a road accident that is reported to nearby vehicles. We focus on sparse deployment of the system which is likely to occur soon after the system is introduced to the market. In this state, the resulting ad hoc network tends to be disconnected. We tailor the proposed algorithm to overcome this problem of network fragmentation. Simulations show us the quality of the proposed protocol by measuring how many vehicles inside a multicast area are informed in time under various conditions.

A novel algorithm to form stable clusters in vehicular ad hoc networks on highways

Abstract: Clustering in vehicular ad hoc networks (VANET) is one of the control schemes used to make VANET global topology less dynamic. Many of the VANET clustering algorithms are derived from mobile ad hoc networks (MANET). However, VANET nodes are characterized by their high mobility, and the existence of VANET nodes in the same geographic proximity does not mean that they exhibit the same mobility patterns. Therefore, VANET clustering schemes should take into consideration the degree of the speed difference among neighboring nodes to produce relatively stable clustering structure. In this paper, we introduce a new clustering technique suitable for the VANET environment on highways with the aim of enhancing the stability of the network topology. This technique takes the speed difference as a parameter to create relatively stable cluster structure. We also developed a new multi-metric algorithm for cluster-head elections. A simulation was conducted to evaluate our method and compare it with the most commonly used clustering methods. The simulation results show that our technique provides more stable cluster structure on the locale scale which results in a more stable network structure on the global scale. The proposed technique reduces the average number of clusters changed per vehicle by 34-46%, and increases the average cluster lifetime by 20-48% compared to the existing techniques.

Vehicular Communications: A Network Layer Perspective

Abstract: Vehicular communications, referring to information exchange among vehicles, infrastructures, etc., have attracted a lot of attention recently due to great potential to support intelligent transportation, various safety applications, and on-road infotainment. In this paper, we provide a comprehensive overview of a recent research on enabling efficient and reliable vehicular communications from the network layer perspective. First, we introduce general applications and unique characteristics of vehicular communication networks and the corresponding classifications. Based on different driving patterns, we categorize vehicular networks into manual driving vehicular networks and automated driving vehicular networks, and then discuss the available communication techniques, network structures, routing protocols, and handoff strategies applied in these vehicular networks. Finally, we identify the challenges confronted by the current vehicular networks and present the corresponding research opportunities.