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This paper describes a failure-resistant network using diversity coding (DC). The technique uses error correcting codes constructed across logically independent virtual paths in ATM networks. This system requires some restrictions on the arrangement of source/destination node pairs in order to avoid increase in parity path capacity. In this paper, the author proposes a network structure where the active paths are divided into several segment networks. This technique enables us to relax constraints on the DC network formation. The author also presents a mechanism for efficient reduction of spare path capacity by partial sharing of spare paths among segment networks. In addition, the author analyzes the performance of spare path capacity reduction and the performance in terms of failure restoration time. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(12): 1–14, 2000 [ABSTRACT FROM AUTHOR]

The land mobile communication is affected by fading when the mobile station moves in the multipath transmission environment. On the other hand, there are cases where there is no fluting as in the communication with the standing or transported mobile station. It has been understood that the coherent detection using PLL is better in the nonfading environment sad the differential detection is better in the fading environment. From such a viewpoint, this paper proposes s detector diversity system for mobile communication which can cope with the complicated states of the transmission path by switching between the coherent detection (PLL) sad the differential detection using the error-detection code. The proposed system uses a simple error-detection code, and the two detectors are switched by selecting the detector with a fewer number of detected errors. The feature of the system is that it is simple, being constructed by the existing PLL and the differential detector. The effectiveness of the proposed system is verified by computer simulation. [ABSTRACT FROM AUTHOR]

This paper proposes an automatic equalizer containing a decoder for an error-correcting code. The purpose is the comprehensive compensation of code errors caused by intersymbol interference due to band-limitation and code errors caused by channel variation and noise. These are major problems in realizing a highly reliable communication. The system is called AEDEC and can reduce the correction error in the tap coefficient innovation due to decision error and the error propagation in a decision-feedback scheme. Consequently, it can achieve a stable convergence in the channel in an adverse condition where a traditional automatic equalizer cannot lead to a convergence. A control method is proposed for innovation of a tap coefficient and data feedback before the feedback decision based on the decoding reliability. This is estimated in the decoding process of the error-correcting code leading to the optimum control, and minimizing the effects of undetection or miscorrection of the decoding errors. Furthermore, as an extension of AEDEC, an adaptive canceller is proposed which eliminates the intersymbol interference without emphasizing noise by utilizing AEDEC as a means of preliminary decision. As a result of computer simulation applying algebraic decoding and analog-weight minimum decoding to recursive (7, 4) Hamming code, it is shown that the proposed schemes can lead to a stable convergence, thereby drastically improving the bit-error rate. [ABSTRACT FROM AUTHOR]