• Journal of Information Processing Systems
• /
• v.15 no.4
• /
• pp.890-903
• /
• 2019

The single carrier frequency domain equalization (SC-FDE) technology is an important part of the broadband wireless access communication system, which can effectively combat the frequency selective fading in the wireless channel. In SC-FDE communication system, the accuracy of timing synchronization directly affects the performance of the SC-FDE system. In this paper, on the basis of Schmidl timing synchronization algorithm a timing synchronization algorithm suitable for FPGA (field programmable gate array) implementation is proposed. In the FPGA implementation of the timing synchronization algorithm, the sliding window accumulation, quantization processing and amplitude reduction techniques are adopted to reduce the complexity in the implementation of FPGA. The simulation results show that the algorithm can effectively realize the timing synchronization function under the condition of reducing computational complexity and hardware overhead.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.6
• /
• pp.213-224
• /
• 2003

The proposed algorithm can always set up the optimal threshold value regardless of channel characteristics using an adaptive threshold establishment method that determines the threshold level according to channel noise power, and then it uses the specially designed training symbols that can make the algorithm's estimation performance be less sensitive to power delay profile variation in a multipath channel. In result, the estimation performance of the proposed technique is less affected by channel characteristic variation.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.2
• /
• pp.19-28
• /
• 1997

This paper presents the design of an SSIC chip for synchronization between main and sub pictures in the multi channel TV system (MUCTS). This chip can resolve problems in MUCTS, such as passing through and vertical jolt phenomena. In addition, this chip rpvivides compatibility for normal/doulble scan, interlace/progressive and normal (4:3)/wide (16:9) systems and has high hjorizontal and vertical resolutions (340) dots and 150 lines). In each mode there are 1 channel, 3 channel, and 4 position display functions. This MUCTS chip including three A/D coverters, a D/A converter and seven line memories was fabricated with one chip by using the $0.8\mu\textrm{m}$ CMOS technology. The application areas of this MUCTS ASIC chip include the wide TV, projection TV and te next generation TV for the DBS (direct broadcast system).

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.8B
• /
• pp.809-818
• /
• 2002

In this paper, we propose a fast cell search algorithm keeping compatible with the standard cell search algorithm of the WCDMA system. The proposed algorithm can acquire the synchronization of slot and frame times, and the code group identification using only one synchronization channel while the standard algorithm employs two synchronization channels called P-SCH and S-SCH. The proposed synchronization channel structure is the same as the P-SCH structure of the WCDMA system. However, the P-SCH is modulated with a specific polarization code, which is one element of new code group codes. The proposed algorithm can reduce both the BS' transmission power and the complexity of receiver as compared with the conventional one since only on synchronization channel is used. It is shown through the computer simulation that the proposed algorithm yields a significant improvement in terms of cell search time compared with the standard especially in low SNR environments.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.8
• /
• pp.2013-2022
• /
• 1996

Cyclic Codes can be used for burs(or time slot) synchronization as well as error detection as that the overhead bits of the burst, which would be nessary to seperate burst synchronization and error detection systems, may be eliminated. In this paper a new method for combined burst synchronization and error detection is proposed which requires CRC decoding once only, while the previous method which inspects channel error after searching for burst synchronization requeires CRC decoding twice. The proposed method has the advantage of simple implementation and reducing processing time over the previous one, still showing the same detection perfdormance. It may occur that a burst different from the actually transmitted one is falsely accepted in the presence of channel errors. The exact expression for the false acceptance probability is newly presented through a simple derivation basied on the fact that it is determined by channel errors but not by detection methods.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.5A
• /
• pp.527-536
• /
• 2004

A novel hybrid multiple access system, TD-BCDMA, where Binary CDMA that maintains a constant amplitude by clipping the summation of input signals multiplied by the orthogonal codes is transmitted over a TDMA frame structure, was Nosed. In every time slot of TDMA, binary CDMA modulated multiple channel signals are transmitted with the same waveform of TDMA. TD-BCDMA has all the advantages of TDMA. Flexible adjustment of the data transmission rate In demand is possible by adjusting the number of codes and time slots assigned to each user. This property was used to show an example of Ad Hoc network applications. To obtain a proper synchronization scheme for TD-BCDMA, the Receiver Operating Characteristics performance and the false alarm probability and false dismissal probability under various channel environment of two different schemes, a preamble scheme as in TDMA and a synchronization channel scheme as in CDMA were compared. It was proved that the preamble scheme is more practical and suitable than the synchronization channel scheme for the hybrid multiple access system.

• Proceedings of the KIEE Conference
• /
• 2008.04a
• /
• pp.159-160
• /
• 2008

Initial Ranging Detection and Synchronization is suggested for IEEE 802.16e OFDMA Systems. However ranging is vulnerable to the channel selectivity and other user's interference at low SNR. This paper presents enhanced ranging scheme that improves ranging detection process using the combine multiple FFT blocks and cope with channel selectivity and other user's interference at low SNR. Based on the ranging detection timing offset is calculated for synchronization.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.10A
• /
• pp.853-858
• /
• 2003

In the EUROCOM communication system, it defines frame structures as data rate. each frame includes a synchronization bit as frame alignment signal. In my paper proposes a FAS detector for determining state of synchronization as compare received data with FAS pattern, also presents a new detection method for synchronization secession which can decide acquisition state of synchronization with searching a synchronization channel through entire channels in frame.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.5
• /
• pp.486-496
• /
• 2013

Time synchronization in underwater environment is challenging due to high propagation delay and mobility of sensor nodes. Previous researches do not consider practical issues affecting on the accuracy of time synchronization such as high-channel access delay and relative position between sensor nodes. Also, those protocols using bidirectional message exchange shorten the network lifetime and decrease the network throughput because numerous transmission, reception and unnecessary overhearing can be occurred. Therefore, in our research, we suggest enhanced time synchronization based on features of underwater environment. It controls the instant of transmission by exploiting the feature of an oceanic movement and node deployment. Moreover, the protocol uses more accurate time information by removing channel access delay from the timestamp. The proposed scheme is also practical on the underwater sensor network requiring low-power consumption because the scheme conducts time-synchronization with smaller transmission and reception compared with previous works. Finally, simulation results show that the proposed protocol deceases time error by 2.5ms and 0.56ms compared with TSHL and MU-Sync respectively, reducing energy consumption by 68.4%.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.66-69
• /
• 1998

The synchronous stream cipher has the advantage that one bit error in the ciphertext only affects the corresponding bit in the plaintext, but it requires the perfect synchronization between encryptor and decryptor. For synchronization, a periodic resynchronization has been used in many applications. In this paper, we propose the periodic resynchronization scheme for radio secure communication and evaluate the performances according to the period of sync pattern and session key under radio channel environment having 10-2~ 10-6 BER.