• Title/Summary/Keyword: Synchronization algorithm

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Fast code synchronization method of the DS-SS/TDMA control channel for satellite communication (직접대역확산 방식의 시분할 다중접속 위성통신 제어채널 고속 부호동기 방법)

  • Ryu, Young-Jae
    • Journal of Satellite, Information and Communications
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    • v.4 no.1
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    • pp.14-20
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    • 2009
  • This paper describes synchronization concept and algorithm of the reverse DS-SS/TDMA control channel to handle satellite terminals which are distributed through the mission area. Military satellite control channel should have ECCM capabilities and handle more than several hundreds satcom terminals simultaneously. DS-SS/TDMA control channel can satisfy these demand but it spend much synchronization time. Proposed algorithm insert the preamble which is divided with several short sub bins prior to control data and use the parallel matched filtering searcher for each sub bin. As a result of the test, proposed algorithm can acquire most of control channel packet successfully within several milliseconds in severe jamming environment.

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Dynamic Allocation Algorithm for enhancement of transmission performance on a radio encryption system (무선암호시스템에서 전송성능 개선을 위한 동적할당 알고리듬)

  • 홍진근;윤장홍;장병화;황찬식
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.11 no.1
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    • pp.3-12
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    • 2001
  • In this paper, a synchronized stream encryption system for secure link layer communication in a radio channel is designed. Interleaving scheme which is used to enhance the transmission performance over a fading channel is applied to the encrypted information. A designed synchronous scream cipher system consists of a keystream generator, a synchronization pattern generator and a session key generator. The structure of a synchronous stream cipher system with periodic synchronization is composed of the encrypted information which consists of a synchronization pattern, an error correcting coded session key, an encrypted data in a period of synchronization. In this paper, interleaving scheme using dynamic allocation a1gorithm(DAA) is applied the encrypted information. The BER of the DAA has been slightly higher than that of the SAA(static allocation algorithm).

Efficient Clock Synchronization Schemes for Enhancing Error Performance of OFDM Wireless Multimedia Communication Systems (OFDM 무선 멀티미디어 통신 시스템의 오율성능 향상을 위한 효율적인 샘플링 클럭 동기방식)

  • 김동옥;윤종호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.1
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    • pp.69-74
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    • 2003
  • In this paper, we propose the synchronization recovery algorithm which is suitable to wireless Multimedia of wireless channel situation which is being used OFDM signaling method. The basic of the suggested clock synchronization. restoration Algorithm is to getting the shock response of channel or getting the multipath strength profile through IFTT after the getting the frequency, response of deducted channel from channel deducted of receiver and to trace the location in the channel energy concentrated area of timing area. And it also analysis the start point of 64-QAM and 16-QAM if the sampling clock offset has the sample of ${\pm}$ 1-3, and we identified the occurance of performance deterioration when occures more than 2 samples of offset to compare with star point and BER performance in optimum sampling point result of BER performance checking, and we know that the recovery algorithm proposed algorithm also provide excellent synchronization characteries under frequency, selecting fading channel as result of simulation.

Robust frame synchronization algorithm in time-varying underwater acoustic communication channel (수중 음향통신에서 채널 시변동성에 강인한 프레임 동기 알고리즘)

  • Ko, Seokjun;Kim, Wan-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.1
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    • pp.8-15
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    • 2020
  • In this paper, we propose a frame synchronization algorithm for robust to the combined effects of large Doppler fluctuations and extended, time-varying multipath in the underwater acoustic communication. From the algorithm, we can recover a high timing error which is occurred from an acoustic propagation delay and uncertainty of oscillator between transmitter and receiver. In order to verify the performance of the synchronization algorithm, the lake trial results are used. The lake experiments are performed in a Gyeongcheonho located in Mungyeong-si, Gyeongsangbuk-do. We can see that the start position of frame is adjusted after the frame synchronization while the receiver moving.

Channel Estimation Method Using Packet Synchronization Sequence for MB-OFDM System (MB-OFDM 시스템에서 Packet Synchronization Sequence를 사용한 채널추정 방식)

  • Shon Soung-Hwan;Lee Kyung-Tak;Kim Jae-Moung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.12A
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    • pp.1174-1182
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    • 2005
  • This paper, we propose a new channel Estimation method for MB-OFDM(Multi-Band OFDM) system that is suggested as one of standards in IEEE 802.15 TG3a for high data rate(110Mbps${\~}$480Mbps) WPAN system. The proposed method uses correlation characteristic of the PS(Packet Synchronization) sequence for timing synchronization. It can reduce the influence of noise compared with the conventional algorithm which based on LS(Least square) algorithm is redundancy without using the CE(Channel Estimation) Sequence for channel Estimation. We simulate both conventional method and proposed method for performance analysis in S-V channel environment which proposed by IEEE 802.15.3a. Simulation results show the proposed algorithm outperforms conventional algorithm about 1${\~}$1.5dB of Eb/NO.

Clock Synchronization in Wireless Embedded Applications (무선 임베디드 환경에서의 시간 동기화)

  • No, Jin-Hong;Hong, Young-Sik
    • Journal of KIISE:Information Networking
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    • v.32 no.6
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    • pp.668-675
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    • 2005
  • With the proliferation of wireless network and the advances of the embedded systems, the traditional distributed systems begin to include the wireless embedded systems. Clock synchronization in the distributed systems is one of the major issues that should be considered for diverse Purposes including synchronization, ordering, and consistency. Many clock synchronization algorithms have been proposed over the years. Since clock synchronization in wireless embedded systems should consider the low bandwidth of a network and the poor resources of a system, most traditional algorithms cannot be applied directly. We propose a clock synchronization algorithm in wireless embedded systems, extending IEEE 802.11 standard. The proposed algorithm can not only achieve high precision by loosening constraints and utilizing the characteristics of wireless broadcast but also provide continuous time synchronization by tolerating the message losses. In master/slave structure the master broadcasts the time information and the stave computes the clock skew and the drift to estimate the synchronized time of the master. The experiment results show that the achieved standard deviation by the Proposed scheme is within the bound of about 200 microseconds.

The Signal Acquisition Algorithm for Ultra Wide-band Communication Systems (UWB 통신시스템에서 동기 획득 알고리즘)

  • Park, Dae-Heon;Kang, Beom-Jin;Park, Jang-Woo;Cho, Sung-Eon
    • Journal of Advanced Navigation Technology
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    • v.12 no.2
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    • pp.146-153
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    • 2008
  • Due to the extremely short pulse in the Ultra-Wideband (UWB) technology, the accurate synchronization acquisition method is very important for both high data-rate WPAN and low data-rate WPAN. In this paper, we propose the synchronization acquisition algorithm based on two-step signal search method to acquire the synchronization in the UWB multi-path channel. At the first step, the search window is divided by two and the window that has higher power is chosen as a next search window. This operation is repeated until the measure power of the search window is smaller than the threshold value. At the second step, we employ Linear Search algorithm to the search window obtained at the first step for fine search. The proposed algorithm is proved that the synchronization acquisition is faster than the parallel search algorithm and it shows good performance in environment of the SNR extreme changes by the simulation.

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An Improved Time Synchronization Algorithm in Sensor Networks (Sensor Network에서의 개선된 망동기화 알고리즘)

  • Jang, Woo-Hyuk;Kwon, Young-Mi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.9
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    • pp.13-19
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    • 2008
  • Time synchronization of nodes in sensor network synchronizes sensor nodes to one time clock. This is very essential in sensor networks so that the information collected and reported from the sensor nodes becomes meaningful. If sensor nodes are not synchronized, disaster report with time information can be wrong analyzed and this may lead to big calamity. With the limitation of battery and computing power, time synchronization algorithm imported in sensor nodes has to be as simple as it doesn't need big complexity, nor generates many synchronization messages. To reduce the synchronization error, hop count should be kept small between reference node to initiate synchronization and sensor nodes to be synchronized. Therefore, multiple reference nodes are used instead of single reference node. The use of multiple reference nodes introduce the requirement of synchronization among reference nodes in the network. Several algorithms have been proposed till now, but the synchronization among reference nodes are not well considered. This paper proposes improved time synchronization for sensor networks by synchronizing multiple reference nodes inside the network. Through simulation, we validated the effects of new algorithm.

Data Transition Minimization Algorithm for Text Image (텍스트 영상에 대한 데이터 천이 최소화 알고리즘)

  • Hwang, Bo-Hyun;Park, Byoung-Soo;Choi, Myung-Ryul
    • Journal of Digital Convergence
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    • v.10 no.11
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    • pp.371-376
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    • 2012
  • In this paper, we propose a new data coding method and its circuits for minimizing data transition in text image. The proposed circuits can solve the synchronization problem between input data and output data in the modified LVDS algorithm. And the proposed algorithm is allowed to transmit two data signals through additional serial data coding method in order to minimize the data transition in text image and can reduce the operating frequency to a half. Thus, we can solve EMI(Electro-Magnetic Interface) problem and reduce the power consumption. The simulation results show that the proposed algorithm and circuits can provide an enhanced data transition minimization in text image and solve the synchronization problem between input data and output data.

An EIBS Algorithm for Wireless Sensor Network with Life Time Prolongation (수명 연장 기능의 무선 센서 네트워크용 EIBS 알고리즘)

  • Bae, Shi-Kyu
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.9
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    • pp.65-73
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    • 2014
  • Since Time synchronization is also critical in Wireless Sensor Networks (WSN) like other networks, a time synchronization protocol for WSN called IBS(Indirect-Broadcast Synchronization) has been already proposed in 2012. As IBS operates in cluster tree topology, network lifetime may be mainly shortened by cluster head node[s], which usually consumes more power than cluster member (i.e. non-cluster head) nodes. In this paper, I propose enhanced version of IBS (called EIBS) which saves overall energy and prolongs network lifetime by re-constructing partial cluster tree locally. Compared with other tree construction approaches, this tree reconstruction algorithm is not only simpler, but also more efficient in the light of overall power consumption and network lifetime.