• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1109-1112
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• 2020

This paper presents a low cost hardware message passing engine of enhanced atomic pipelined broadcast based on processing node status. In this algorithm, the previous atomic pipelined broadcast algorithm is modified to reduce the waiting time until next broadcast communication. For this, the processor change the transmission order of processing nodes based on the nodes' communication channel. Also, the hardware message passing engine architecture of the proposed algorithm is modified to be adopted to multi-core processor. The synthesized logic area of the proposed hardware message passing engine was reduced by about 16%, compared by the pre-existing hardware message passing engine.

• Journal of the Korean Data and Information Science Society
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• v.21 no.4
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• pp.783-793
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• 2010

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or propagate useful traffic information to other vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collisions at the link layer due to an excessive number of broadcast packets. We present a fuzzy alert message dissemination algorithm to improve performance for road safety alert application in Vehicular Ad-hoc Network (VANET). In the proposed algorithm, when a vehicle receives an alert message for the first time, the vehicle rebroadcasts the alert message according to the fuzzy control rules for rebroadcast degree, where the rebroadcast degree depends on the current traffic density of the road and the distance between source vehicle and destination vehicle. Also, the proposed algorithm is the hybrid algorithm that uses broadcast protocol together with token protocol according to traffic density. The performance of the proposed algorithm is evaluated through simulation and compared with that of other alert message dissemination algorithms.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1297-1307
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• 2013

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or disseminate useful traffic information to othet vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collision at the link layer due to an excessive number of broadcast packets. To solve broadcast storm problem, we propose an RPB-MACn-based LV-CAST that is a vehicular broadcast algorithm for disseminating safety-related emergency message. The proposed LV-CAST identifies the last node within transmission range by computing the distance extending on 1 hop from the sending node of an emergency message to the next node of receiving node of the emergency message, and the last node only re-broadcasts the emergency message. The performance of LV-CAST is evaluated through simulation and compared with other message dissemination algorithms.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.41-47
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• 2010

The emergency between vehicles on the superhighway should be transmitted quickly to the following vehicles for safety of people. The message between them has been transmitted by broadcast method in an wireless environment of 802.11, so far. That causes the broadcast storm and a waste of the bandwidth of Wireless network owing to unnecessary process of sending messages to even vehicles that do not have to receive the information. The message collision is a main cause of the increase of message delay. In order to overcome the existing problem, this paper proposed a message broadcast scheme based on cell (MBC), which is the way to divide cars into different groups by cell unit and transmit messages to the members of the groups through the cell primary (cp) vehicles. This paper shows the proposed broadcast's performance in the same environment is much superior to other conventional broadcast schems for inter-vehicle communication, since the receiving ratio among the following vehicles is improved.

• Journal of Broadcast Engineering
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• v.26 no.5
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• pp.592-598
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• 2021

Current cellular systems rely on a CBS protocol for emergency alert broadcast services. However, the CBS protocol just specifies the delivery of a limited text message. Therefore, foreigners, who are unfamiliar with local characters, may have some difficulties in understanding the received CBS text message. The CBS protocol also reveals a distinct restriction in delivering abundant information because of a limited number of text characters. In order to overcome the weak points of the current CBS protocol, we propose a display method of image information and URL on the screens of mobile terminals for the received CBS text message in this paper. The presented approach effectively utilizes the message structure of CBS for 5G cellular systems.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.125-133
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• 2002

In this paper, we present an efficient broadcast protocol, called Btoken, that ensures total ordering of messages and atomicity of delivery in the large scaled distributed systems. Unlike the existing token-passing based protocol, Btoken does not circulate a token around the ring, instead, it uses three kinds of control messages for token transmission. The token has a sequence number field for broadcasting message, and the only site having the token can broadcast a message. When a site wishes to broadcast, It must send a message to the token site requesting the token. The token site sends a message with the token to the requester When the requester receives the token, it becomes the current token site and broadcasts a new message after setting sequence number derived from a field of the token into its message. Upon reception of it, any operating member is informed the position of the token site and will send token requesting message to the new token site. However, the other site may request the token to the old token site prior to receiving the broadcast message from the new token site. To resolve this problem, Btoken uses a message which is sent to the current token site by the old token site notifying who is the next token requester. Results of our simulation of the protocol show that Btoken is more efficient in the large scaled distributed system compared to existing broadcast protocols.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.411-432
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• 2010

We consider three different secure broadcasting scenarios: i) Broadcast channels with common and confidential messages (BCC), ii) multi-receiver wiretap channels with public and confidential messages, and iii) compound wiretap channels. The BCC is a broadcast channel with two users, where in addition to the common message sent to both users, a private message, which needs to be kept hidden as much as possible from the other user, is sent to each user. In this model, each user treats the other user as an eavesdropper. The multi-receiver wiretap channel is a broadcast channel with two legitimate users and an external eavesdropper, where the transmitter sends a pair of public and confidential messages to each legitimate user. Although there is no secrecy concern about the public messages, the confidential messages need to be kept perfectly secret from the eavesdropper. The compound wiretap channel is a compound broadcast channel with a group of legitimate users and a group of eavesdroppers. In this model, the transmitter sends a common confidential message to the legitimate users, and this confidential message needs to be kept perfectly secret from all eavesdroppers. In this paper, we provide a survey of the existing information-theoretic results for these three forms of secure broadcasting problems, with a closer look at the Gaussian multiple-input multiple-output (MIMO) channel models. We also present the existing results for the more general discrete memoryless channel models, as they are often the first step in obtaining the capacity results for the corresponding Gaussian MIMO channel models.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.204-205
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• 2013

최근 일본의 지진 쓰나미 등 전 세계적으로 많은 재난이 증가하고 있고, 국내에서는 신속한 재난 정보 전송을 위해서 CBS(Cell Broadcast Service) Alert Message를 국가 표준으로 제정하였다. CBS를 통한 전송은 지역단위 전송이 가능하므로 재난이 발생한 지역에 신속한 전송 서비스를 가능하게 해준다. 하지만 국내의 경우 CBS Alert Message가 LTE(Long Term Evolution) 단말에서만 수신이 가능하고 3G 단말에서는 수신이 불가능하다. 이에 본 논문은 실내 환경에서 gateway-AP(Access Point)를 이용하여 3G 단말이 CBS Alert Message를 수신 할 수 있는 방법을 제시하려고 한다.

• MALSORI
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• no.64
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• pp.15-37
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• 2007

The purpose of this paper is to examine the change of the times on the transmission rate of broadcast message. In order to find out the research results, I collected past recorded news tapes and selected 22 radio news out from era of Japanese Imperialism, 1950's, 1960's and contemporary age. Next I measured each announcer's reading rate, and compared change on news-reading rate between present and past approximately 50 years ago. The results of study with such procedures and methods are as follows : the average reporting rate of newscasters in each era is different. From these results, we can easily grasp diachronic change in the transmission rate of broadcast message. Namely, the results show us that present announcers read news faster than the group of past era of Japanese Imperialism by 68%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1152-1167
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• 2018

In this paper, I propose an application layer cooperative congestion control scheme for safety message broadcast in vehicular networks, called CMS, that adaptively controls a vehicle's safety message rate and transmit timing based on the channel congestion state. Motivated by the fact that all vehicles should transmit and receive an application layer safety message in a periodic manner, I directly exploit the message itself as a means of estimating the channel congestion state. In particular, vehicles can determine wider network conditions by appending their local channel estimation result onto safety message transmissions and sharing them with each other. In result CMS realizes cooperative congestion control without any modification of the existing MAC protocol. I present extensive NS-3 simulation results which show that CMS outperforms conventional congestion control schemes in terms of the packet collision rate and throughput, especially in a high-density traffic environment.