A branching process analysis in random environment is presented for bounding the average number of computations of sequential decoding over a finite state channel. Closed-form expressions applicable to specific cases ...
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A branching process analysis in random environment is presented for bounding the average number of computations of sequential decoding over a finite state channel. Closed-form expressions applicable to specific cases are derived and evaluated. These unique bounds substantially reduce the need for lengthy simulations.
The error probability of reduced-state sequence estimation (RSSE) for trellis-coded modulation (TCM) on intersymbol interference channels is evaluated. A method based on a stack algorithm is proposed to evaluate the u...
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The error probability of reduced-state sequence estimation (RSSE) for trellis-coded modulation (TCM) on intersymbol interference channels is evaluated. A method based on a stack algorithm is proposed to evaluate the union bound on the error probability for ideal RSSE which is a good approximation to the error probability of real RSSE. The stack algorithm is employed because it provides a good tradeoff between computer memory and computing time.
The performance of ideal reduced-state sequence estimation (RSSE) (without error propagation) is known as a good approximation to the performance of real RSSE. In the literature, the minimum distance of ideal RSSE has...
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The performance of ideal reduced-state sequence estimation (RSSE) (without error propagation) is known as a good approximation to the performance of real RSSE. In the literature, the minimum distance of ideal RSSE has been employed for approximating the error probability of real RSSE. However, this approximation can be very poor, even though the system has a large signal-to-noise ratio. In this paper, a union upper bound on the error probability for ideal RSSE is used to approximate the true error probability. This union bound provides a better approximation than the minimum distance. A new method based on a stack algorithm and a subset-error state diagram is proposed for calculating this union bound. The stack algorithm is employed because it provides a good tradeoff between computer memory and computing time.
An exact performance evaluation of the free-access stack collision resolution algorithm is given under the hypotheses of carrier-sense multiple access with collision detection (CSMA-CD) local area network communicatio...
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An exact performance evaluation of the free-access stack collision resolution algorithm is given under the hypotheses of carrier-sense multiple access with collision detection (CSMA-CD) local area network communication with packets of different length. In particular, the packet delay moments (mean and variance) and the maximum throughput that the system achieves for any given packet length distribution are precisely described.
The performance of a receiver using a combined MLSE equalizer/decoder and D-diversity reception is analyzed for multipath Rayleigh fading channels. A new upper bound on the (decoded) bit error probability is derived. ...
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The performance of a receiver using a combined MLSE equalizer/decoder and D-diversity reception is analyzed for multipath Rayleigh fading channels. A new upper bound on the (decoded) bit error probability is derived. Comparisons to simulation results show that this upper bound is quite tight when the system has a high signal-to-noise ratio or when diversity reception is employed. The upper bound involves an infinite series that must be truncated at a point where the remainder can be safely assumed to be small. An algorithm which is based on a one-directional stack algorithm is proposed for this calculation, because it makes efficient use of computer memory.
Cursive script word recognition is the problem of transforming a word from the iconic form of cursive writing to its symbolic form. Several component processes of a recognition system for isolated offline cursive scri...
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Cursive script word recognition is the problem of transforming a word from the iconic form of cursive writing to its symbolic form. Several component processes of a recognition system for isolated offline cursive script words are described. A word image is transformed through a hierarchy of representation levels: points, contours, features, letters, and words. A unique feature representation is generated bottom-up from the image using statistical dependences between letters and features. Ratings for partially formed words are computed using a stack algorithm and a lexicon represented as a trie. Several novel techniques for low- and intermediate-level processing for cursive script are described, including heuristics for reference line finding, letter segmentation based on detecting local minima along the lower contour and areas with low vertical profiles, simultaneous encoding of contours and their topological relationships, extracting features, and finding shape-oriented events. Experiments demonstrating the performance of the system are also described.
A systolic array processing technique is applied to implementing the stack algorithm form of the sequential decoding algorithm. It is shown that sorting, a key function in the stack algorithm, can be efficiently reali...
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A systolic array processing technique is applied to implementing the stack algorithm form of the sequential decoding algorithm. It is shown that sorting, a key function in the stack algorithm, can be efficiently realized by a special type of systolic arrays known as systolic priority queues. Compared to the stack-bucket algorithm, this approach is shown to have the advantages that the decoding always moves along the optimal path, that it has a fast and constant decoding speed and that its simple and regular hardware architecture is suitable for VLSI implementation. Three types of systolic priority queues are discussed: random access scheme, shift register scheme and ripple register scheme. The property of the entries stored in the systolic priority queue is also investigated. The results are applicable to many other basic sorting type problems.
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