• 한국국방경영분석학회지
• /
• 제15권2호
• /
• pp.56-77
• /
• 1989

A new concept, namely the error discrimination of a code defined as the capability to not only detect errors from two distinct error sets but also to distinguish between them has been introduced in [SAKA 89a]. Consider $E_+\;and\;E_-$ as the two distinct error sets, namely the positive error set and the negative error set respectively. If a code C is not only capable of detecting any error e in {$E_+,\;E_-$}, but also able to identify the error set to which e belongs then the code is said to be an $E_+\;&\;E_-$ error discriminating code. The error discriminating property enables construction of unidirectional error detecting/correcting codes using asymmetric error control code. We derive here theory for asymmetric t error correcting and d error detecting codes. Furthermore, unidirectional error control code construction methods are introduced using asymmetric error control codes and $E_+\;&\;E_-$ error discriminating codes.

• Journal of Communications and Networks
• /
• 제17권1호
• /
• pp.12-20
• /
• 2015

Convolutional codes which are terminated by direct truncation (DT) and zero tail termination provide unequal error protection. When DT terminated convolutional codes are used to encode short messages, they have interesting error protection properties. Such codes match the significance of the output bits of common quantizers and therefore lead to a low mean square error (MSE) when they are used to encode quantizer outputs which are transmitted via a noisy digital communication system. A code construction method that allows adapting the code to the channel is introduced, which is based on time-varying convolutional codes. We can show by simulations that DT terminated convolutional codes lead to a lower MSE than standard block codes for all channel conditions. Furthermore, we develop an MSE approximation which is based on an upper bound on the error probability per information bit. By means of this MSE approximation, we compare the convolutional codes to linear unequal error protection code construction methods from the literature for code dimensions which are relevant in analog to digital conversion systems. In numerous situations, the DT terminated convolutional codes have the lowest MSE among all codes.

• 제어로봇시스템학회논문지
• /
• 제8권4호
• /
• pp.299-302
• /
• 2002

Error detection and correction using CRC and the general class of cyclic codes is an important part of designing reliable data transmission schemes. The decoding method for cyclic codes using covering patterns is easily-implementable, and its complexity de-pends on the number of covering patterns employed. Determination of the minimal set of covering patterns for a given code is an open problem. In this paper, an efficient search method for constructing minimal sets of covering patterns is proposed and compared with several existing search methods. The result is applicable to various codes of practical interest.

• Journal of Communications and Networks
• /
• 제5권3호
• /
• pp.187-196
• /
• 2003

We consider the use of error control coding in direct sequence-code-division multiple access (OS-COMA) systems that employ multiuser detection (MUO) and space diversity. The relative performance gain between Reed-Solomon (RS) code and convolutional code (CC) is well known in [1] for the single user, additive white Gaussian noise (AWGN) channel. In this case, RS codes outperform CC's at high signal-to-noise ratios. We find that this is not the case for the multiuser interference channel mentioned above. For useful error rates, we find that soft-decision CC's to be uniformly better than RS codes when used with DS-COMA modulation in multiuser space-time channels. In our development, we use the Gaussian approximation on the interference to determine performance error bounds for systems with low number of users. Then, we check their accuracy in error rate estimation via system's simulation. These performance bounds will in turn allow us to consider a large number of users where we can estimate the gain in user-capacity due to channel coding. Lastly, the use of turbo codes is considered where it is shown that they offer a coding gain of 2.5 dB relative to soft-decision CC.

• Journal of Communications and Networks
• /
• 제17권3호
• /
• pp.221-230
• /
• 2015

Rateless codes have been shown to be able to provide greater flexibility and efficiency than fixed-rate codes for multicast applications. In the following, we optimize rateless codes for unequal error protection (UEP) for multimedia multicasting to a set of heterogeneous users. The proposed designs have the objectives of providing either guaranteed or best-effort quality of service (QoS). A randomly interleaved rateless encoder is proposed whereby users only need to decode symbols up to their own QoS level. The proposed coder is optimized based on measured transmission properties of standardized raptor codes over wireless channels. It is shown that a guaranteed QoS problem formulation can be transformed into a convex optimization problem, yielding a globally optimal solution. Numerical results demonstrate that the proposed optimized random interleaved UEP rateless coder's performance compares favorably with that of other recently proposed UEP rateless codes.

• ETRI Journal
• /
• 제38권2호
• /
• pp.326-336
• /
• 2016

We propose and describe new error control algorithms for redundant residue number systems (RRNSs) and residue number system product codes. These algorithms employ search techniques for obtaining error values from within a set of values (that contains all possible error values). For a given RRNS, the error control algorithms have a computational complexity of $t{\cdot}O(log_2\;n+log_2\;{\bar{m}})$ comparison operations, where t denotes the error correcting capability, n denotes the number of moduli, and ${\bar{m}}$ denotes the geometric average of moduli. These algorithms avoid most modular operations. We describe a refinement to the proposed algorithms that further avoids the modular operation required in their respective first steps, with an increase of ${\lceil}log_2\;n{\rceil}$ to their computational complexity. The new algorithms provide significant computational advantages over existing methods.

• 정보보호학회논문지
• /
• 제1권1호
• /
• pp.66-78
• /
• 1991

본 논문에서는 스트림 암호시스템의 종류와 오류전파 특성에 대해 분석한다. 또한, 암호문 전송중 전송로상에서 발생하는 오류르 제어할 목적으로 DSEC(31, 27) RS 부호를 암호문 귀환암호시스템에 내부오류제어 및 외부오류제어로 분류하여 적용하고 오류정정과정을 분석한다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.907-910
• /
• 2009

본 논문에서는 디지털 이미지의 무선 전송시 발생하는 에러를 제거 할 수 있는 오류 제어 부호화 기술 중 하나인 RS(Reed-Solomon) coding 중 Encoder의 FPGA 구현에 대한 논문이다. 여러 오류 제어 부호화 기술중 RS coding의 경우 비트가 아닌 심볼로 부호화를 하기 때문에 연집에러에 강한 것으로 알려져 있다. 본 논문에서는 RS coding중 최대 16바이트(Byte)의 에러를 정정할 수 있는 RS(255,223) 부호기를 FPGA 구현을 위해 Matlab을 이용하여 시뮬레이션을 하였다. 이때 사용한 영상은 JPG 파일을 이용하였다. 그리고 FPGA 구현을 위해 Xilinx사의 System Generator를 사용 하였다.

• 전자공학회논문지A
• /
• 제28A권5호
• /
• pp.339-346
• /
• 1991

In this paper the performance of communication system in the electrical power line using error correcting codes is analysed. The BCH codes and interleaved code are to be used for correcting burst and random errors in the power line channels. The data rate of 2400 bps and the carrier frequency of 12KHz are assumed. Actual power line noise is recorded and simulated in the BPSK PLC system model.

• 한국통신학회논문지
• /
• 제26권8A호
• /
• pp.1437-1440
• /
• 2001

We present a modification method for runlength limited codes based on convolutional codes. This method is based on cosets of convolutional codes and can be applied to any convolutional code without degradation of error control performance of the codes. The upper bound of maximum zero and/or one runlength are provided. Some convolutional codes which have the shortest maximum runlength for given coding parameters are tabulated.