• The Journal of Information Technology
• /
• v.9 no.4
• /
• pp.57-63
• /
• 2006

The intelligent elder brother groove network robot service the new broadband presence line is conversionce application service. Robot control data transmission hazard UDP packet of the remote control data which stands duplication necessary to transmit. TCP the error ratio to be high qualitative recording transmission pattern it of the transmission unit and is irregular the distance is distant to show and also the transmission lag is visible increases. The recording packet drop whose UDP degree error ratio will be high is frequent and does not arrive packet little by little increases is a possibility of knowing in the transmission unit. The technique which it proposes with traffic pattern of the transmission unit is visible the transfer characteristic of the same shape from 1% packet error ratio degree. The effective transmission technique of the robot control data which puts a base in UDP protocols was proposed from the present paper. Following research it leads and it follows the duplication transmission number of time in error rate of radio link and it was thought all that controls petty the research of the mechanism which progresses is necessary.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.6
• /
• pp.11-22
• /
• 1996

We address an issue of channel sharing among users by using a random assignment-transmitter-based (RA-T) spread-spectrum transmission scheme which permits the contention mode only in the transmission of a header while avoiding collision during the data packet transmission. Once the header being successfully received, the data packet is ready for reception by switching to one of programmable matched-filters. But the receoption may be blocked due to limited number of matched-filters so that this effect is taken into account in our analysis. For realistic analysis, we integrate detection performance at the physical level with channel activity at the link level through a markov chain model. We also consider an acknowledgement scheme to notify whether the header is correctly detcted and the data packet can be processed continuously, which aims at reducing the interference caused unwanted data transmission. It is shown that receiver complexity can be greatly reduced by choosing a proper number of RA codes at the cost of only a little throughput degradation.

• Proceedings of the IEEK Conference
• /
• 2002.06a
• /
• pp.327-330
• /
• 2002

In this paper, we have analyzed transmission time for WAP over CDMA using turbo code scheme. In order for SAR to improve the transfer capability, the transmission of messages have been simulated using a fragmentation that begins with the total package and incremental fragmentation for each layer using the WTP to define tile resultant packet size and the level of fragmentation for each proceeding layer. This turbo code scheme decreases transmission lime of RLP baseband packets. From the results, we arc able to obtain packet transmission time and optimal WTP packet size for WAP over CDMA in a Rician fading channel.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.317-320
• /
• 2004

In this paper, it is analyzed a performance improvement of ACL Packet using turbo code scheme in bluetooth system. In order for segment to improve the transfer capability, the transmission of messages have been simulated using a fragmentation that begins with the total package and incremental fragmentation for each layer using the TCP to define the resultant packet size and the level of fragmentation for each proceeding layer. This turbo code scheme decreases transmission time of L2CAP baseband packets by sending packets. From the results, we were able to obtain packet transmission time, optimal TCP packet size, ACL(DM packet) in AWGN.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.2 s.332
• /
• pp.23-38
• /
• 2005

The state of channel between two or more wireless terminals is changed frequently due to noise or multiple environmental conditions in wireless network. In this paper, we analyze packet transmission time and queue length in a time-varying channel of packet based Wireless Networks. To reflect the feature of the time-varying channel, we model the channel as two-state Markov model and three-state Markov model Which are transformed to SFG(Signal Flow Graph) model, and then the distribution of the packet transmission can be modeled as Gaussian distribution. If the packet is arrived with Poisson distribution, then the packet transmission system is modeled as M/G/1. The average transmission time and the average queue length are analyzed in the time-varying channel, and are verified with some simulations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.5
• /
• pp.907-915
• /
• 2003

A very efficient packet transmission scheme is needed in the radio environment where radio resource is insufficient as compared with the environment of the wired communication. In general, dual mode packet transmission scheme is used broadly. Packets are transmitted through the dedicated or common chamois according to a switching criterion. The general criteria are the length and generation frequency of packet, that is, large and frequent packets are transmitted using a dedicated channel and small and infrequent packets are transmitted using a common channel. The performance of dual mode packet transmission scheme is closely related to the switching criteria. However, it is very difficult to find the optimal switching point because that is not fixed but variable according to the environment such as traffic load, length of generated packets, and the number of channels. In this paper, a new scheme for the dual mode packet transmission scheme using a dynamic switching threshold is proposed where the switching threshold is not fixed but variable according to the network environment. The performance of the proposed method is analyzed using a simulation. From the simulation results, it is shown that the performance of the proposed scheme is not very influenced by the network environment unlike the conventional dual mode packet transmission scheme.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.10
• /
• pp.101-110
• /
• 2009

The 6LoWPAN(IPv6 Low-power Wireless Personal Area Network) performs IPv6 header compression, TCP/UDP/IGMP header compression, packet fragmentation and re-assemble to transmit IPv6 packet over IEEE 802,15.4 MAC/PHY. However, from the point of view of security. It has the existing security threats issued by IP packet fragmenting and reassembling, and new security threats issued by 6LoWPAN packet fragmenting and reassembling would be introduced additionally. If fragmented packets are retransmitted by replay attacks frequently, sensor nodes will be confronted with the communication disruption. This paper analysis security threats introduced by 6LoWPAN fragmenting and reassembling, and proposes a re-transmission mechanism that could minimize re-transmission to be issued by replay attacks. Re-transmission procedure and fragmented packet structure based on the 6LoWPAN standard(RFC4944) are designed. We estimate also re-transmission delay of the proposed mechanism. The mechanism utilizes timestamp, nonce, and checksum to protect replay attacks. It could minimize reassemble buffer overflow, waste of computing resource, node rebooting etc., by removing packet fragmentation and reassemble unnecessary.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.11B
• /
• pp.1216-1224
• /
• 2009

This paper presents cross-layer based packet scheduling and routing algorithm to effectively transmit delay-sensitive multimedia data over mobile ad hoc network. At first, packet urgency, node urgency, and route urgency are defined based on the end-to-end delay requirement of each packet and the number of hops over a route. Based on the urgency metric, the proposed transmission scheme is that packet scheduling algorithm at the MAC layer and routing algorithm at the network layer are tightly-coupled to improve the transmission performance for delay-sensitive multimedia. Finally, simulation results are provided to show the performance of proposed transmission scheme.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.8
• /
• pp.77-84
• /
• 2011

In this paper we implement a 6LoWPAN protocol on the MICAz sensor platform, which could minimize packet re-transmission, and support security primitives for packet integrity and confidentiality. And we also present a performance evaluation of the implemented protocol calculated according to the cryptographic algorithms. In the re-transmission method, time stamp, nonce, and checksum are considered to protect replay attacks. As cryptographic algorithms, AES, 3DES, SHA2, and SHA1 are implemented. If transmission errors (thus, packet losses) and the number of hops are increase then, packet re-transmissions are increase exponentially from the experimental results. Also, the result shows that cryptographic operations take more time than packet re-transmission time.

• The KIPS Transactions:PartA
• /
• v.13A no.7 s.104
• /
• pp.573-580
• /
• 2006

The conventional transport layer protocol TCP is designed to work under condition of packet loss is due to the network congestion, so that it's suitable in the traditional wired network with fixed hosts but it's inefficient on the wireless network where the environment of fading, noise, and transmission error comes from interference. This result from the needless transmission control of the bit error is due to treats the packet loss as a packet congestion control in the wireless network. In this paper, we propose the advanced SNOOP protocol with the consecutive packet loss and TCP window control to avoid the needless congestion management algorithm in wireless network for the wireless TCP packet transmission enhancement. We verify the performance of the advanced module from the simulation experiment result.