Koichiro Hashiura

Analysis of Packet Compensation Protocols with MCS/CDMA for Local Broadcasting Services

The purpose of this paper is to compensate loss packets in the broadcasting services using road to vehicle communications (RVC). In particular, the push-type packet compensation protocol with multi-code sense code division multiple access (MCS/CDMA) (push scheme) and the pull-type packet compensation protocol with MCS/CDMA (pull scheme) are considered. The blocking probability and the average number of packet transmissions are analyzed. As the result, the average number of packet transmissions of the pull scheme is smaller than that of the push scheme. Therefore the pull scheme is superior to the push scheme in the power consumption

Construction of hierarchical optical broadcasting systems for intelligent transport system

The local broadcast systems, that transmit both the wide-area information and the local-area information, are proposed. A nearby user, which is near to the broadcasting station, demodulates together the wide-area information and local-area information. Even if a distant user, which is far to the station, does not receive the local-area information, it is expected that he receives wide-area information only. In the proposed systems, the broadcast information is hierarchized by combining the two modulation scheme. In particular, the two proposed systems are described; the ASK-CSK system which combines amplitude-shift-keying(ASK) with code-shift-keying(CSK) and the CNK-CSK system which combines code-number-keying(CNK) with CSK. The CNK-CSK system is superior to the ASK-CSK system.

Performance evaluation of the vehicular ad-hoc network using the modified binary countdown scheme

In the Intelligent Transport System (ITS), the vehicular ad hoc network (VANET) system is focused. In VANET, to construct the media access control (MAC) scheme is important. In this paper, the modified binary countdown scheme is proposed as MAC protocol. This scheme is introduced the modified binary countdown scheme to the slotted ALOHA-based scheme. In this scheme, the transmission frame is divided into NS slots. The users choose a slot and a priority code at random. The users countdown at the chosen slot. The user who has the highest priority code transmits a packet. This scheme keeps the fairness of the transmission chance. As the results of the computer simulation, it is shown that the VANET using the modified binary countdown scheme outperforms the conventional binary countdown scheme.

Theoretical Analysis of Spread-Spectrum Push/Pull Type Packet Compensation Protocol on Local Broadcasting Services

The purpose of this paper is to compensate loss packet in the broadcasting system using road to vehicle communications (RVC). Authors have proposed and evaluated the push-type and pull-type packet compensation protocol. These protocols are the loss packet compensation protocol using inter-vehicle communications (IVC). In this paper, the push/pull-type packet compensation protocol with common spreading sequences for broadcasting system is proposed. The average packet acquisition time is analyzed. By comparing with the pull-type packet compensation protocol, the push/pull-type packet compensation protocol is more efficient than the pull-type packet compensation protocol.

Performance analysis of pull-type packet compensation protocol with perfect MCS/CDMA for the broadcasting system

The purpose of this paper is to analyze the pull-type packet compensation protocol with perfect multi-code sense code division multiple access (MCS/CDMA). MCS/CDMA is the access control that the user who transmits the packet estimates the unused code and the packet is spread by the code. In this paper, the average packet acquisition time and the average number of remaining unsuccessful users after n compensation procedures are analyzed. Moreover, the pull-type packet compensation protocol using MCS is compared with the pull-type packet compensation protocol using random code selection. As the results, MCS/CDMA is effective in the pull-type packet compensation protocol for broadcasting service because the average packet acquisition time of MCS/CDMA is shorter than that of random code selection.

Performance evaluation of the pull-type packet compensation protocol with common spreading sequences for broadcasting system

The purpose of this paper is to evaluate performance of the pull-type packet compensation protocol with common spreading sequences by theoretical analysis. This protocol is the loss packet compensation scheme for broadcasting services using road to vehicle communications (RVC). In this paper, the blocking probability, the average time to complete compensation and the average number of packet transmissions are analyzed. As the result, the pull-type packet compensation protocol outperforms the push-type packet compensation protocol

Theoretical analysis of the modified binary countdown scheme

To design and evaluate the media access control scheme is important for the vehicular ad-hoc network (VANET) systems. As MAC scheme, the modified binary countdown scheme is considered. However, this scheme is not analyzed in theory. In this paper, the average packet acquisition time of the basic modified binary countdown scheme is evaluated by the theoretical analysis. Compared with the results of the computer simulation, the little difference is occurred between the theoretical value and the simulation value occur by the users allocation.

Performance of the slot-distributed push-type packet compensation protocol for the road to vehicle broadcasting system

In this paper, the road to vehicle broadcasting system are considered. As the error control protocol of this system, the push-type packet compensation protocol using spread-spectrum have been proposed. However, when the number of users increasing significantly, the average packet acquisition time of this protocol deteriorates by the packet collision. In order to overcome this problem, the slot-distributed push-type packet compensation protocol is proposed and analyzed. Consequently, it is shown that the proposed protocol is effective on the high user density.

Performance Improvement of the Inter-Vehicle Push-Type Packet Compensation Protocol for the Road to Vehicle Broadcasting System

This paper is focused on the packet compensation protocol using Spread-Spectrum (SS) techniques for the road to vehicle broadcasting system. The SS slot-distributed push-type packet compensation protocol is proposed. Moreover, the average packet acquisition time and the average transmission power for compensating a lost packet are evaluated by the theoretical analysis and the computer simulation. As the results, the average packet acquisition time of the proposed protocol is shorter than that of the conventional CDMA packet compensation protocol. The average energy of the proposed protocol is smaller than that of the conventional BPSK system.

Performance of the asynchronous push-type packet compensation methods for road-to-vehicle broadcasting system

The push-type packet compensation protocol using the random slot/code selection method have been proposed and evaluated in the synchronous case. However, it is difficult to synchronize between all users. In this paper, the push-type packet compensation protocol using the random slot/code selection method is evaluated by the computer simulation in the asynchronous case. As the results, the random slot/code selection method is effective in the error control method of the road-to-vehicle broadcasting system.