In the future, 5G radio access and support for the internet of things (IoT) is becoming more important, which is called machine type communications. Different from current mobile communication systems, machine type co...
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In the future, 5G radio access and support for the internet of things (IoT) is becoming more important, which is called machine type communications. Different from current mobile communication systems, machine type communications generates relatively small packets. In order to support such small packets with high reliability, channel coding techniques are inevitable. One of the most effective channel codes in such conditions is the tail-biting convolutional code, since it is used in LTE systems due to its good performance for small packet sizes. By employing a list viterbi algorithm for the tail-biting convolutional code, the block error rate (BLER) performances is further improved. Therefore, this paper evaluates the BLER performances of several list viterbi algorithms, i.e., circular parallel list viterbi algorithm (CPLVA), per stage CPLVA (PSCPLVA), and successive state and sequence estimation (SSSE). In the evaluation, computational complexity is also taken into account. It is shown that the performance of the CPLVA is better in the wide range of computational complexity defined in this paper.
In many real-world communication systems, the channel noise is non-Gaussian due to the presence of impulsive noise as well as the background Gaussian noise. In such situations, the conventional Euclidean distance base...
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In many real-world communication systems, the channel noise is non-Gaussian due to the presence of impulsive noise as well as the background Gaussian noise. In such situations, the conventional Euclidean distance based decoder may suffer from the problem of severe metric mismatch. To overcome the problem, we recently proposed the joint erasure marking and viterbialgorithm (JEVA) as a robust trellis decoder that does not require an estimate of the impulsive noise distribution. In this work, two ways to further improve JEVA are presented for systems with an error detecting code. Specifically, the JEVA is integrated with the list viterbi algorithm (LVA) to form the two-dimensional joint erasure marking and list viterbi algorithm (JELVA) and the switched JELVA, respectively. By combining the respective strengths of the JEVA and the LVA, the integrated decoding schemes are able to achieve significant performance gains over the original JEVA and achieve a wide range of performance-complexity-delay tradeoffs.
This paper addresses the air traffic control problem of conflict detection and resolution (CDR) under intent uncertainty, in a multiple model (MM) trajectory information processing framework. The conflict detection is...
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ISBN:
(纸本)9780982443866
This paper addresses the air traffic control problem of conflict detection and resolution (CDR) under intent uncertainty, in a multiple model (MM) trajectory information processing framework. The conflict detection is based on a predicted probability of conflict. The problem of conflict resolution (CR) is formulated as one of achance-constrained model predictive control, whereby the constraint is imposed on the probability of conflict, set to guarantee a desired level of safety (in a probabilistic sense). An efficient algorithm for CDR is proposed that utilizes a list viterbi algorithm for finding an optimal, conflict-free, MM-maneuver sequence for CR. The capability and computational efficiency of the proposed algorithm are demonstrated by simulation of several "sense-and-avoid" UAV encounter scenarios that involve one or more intruders and horizontal and vertical MM-maneuvers for CR.
Recently, CRC-aided list decoding of convolutional codes has gained attention thanks to its remarkable performance in the short blocklength regime. This paper studies the convolutional and CRC codes of the Consultativ...
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Recently, CRC-aided list decoding of convolutional codes has gained attention thanks to its remarkable performance in the short blocklength regime. This paper studies the convolutional and CRC codes of the Consultative Committee for Space Data System Telemetry recommendation used in space missions by all international space agencies. The distance spectrum of the concatenated CRC-convolutional code and an upper bound on its frame error rate are derived, showing the availability of a 3 dB coding gain when compared to the maximum likelihood decoding of the convolutional code alone. The analytic bounds are then compared with Monte Carlo simulations for frame error rates achieved by listviterbi decoding of the concatenated codes, for various list sizes. A remarkable outcome is the possibility of approaching the 3 dB coding gain with nearly the same decoding complexity of the plain viterbi decoding of the inner convolutional code, at the expense of slightly increasing the undetected frame error rates at medium-high signal-to-noise ratios. Comparisons with CCSDS turbo codes and low-density parity check codes highlight the effectiveness of the proposed solution for onboard utilization on small satellites and cubesats, due to the reduced encoder complexity and excellent error rate performance.
Hybrid in-band on-channel digital audio broadcasting systems deliver digital audio signals in such a way that is backward compatible with existing analog FM transmission. We present a channel error correction and dete...
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Hybrid in-band on-channel digital audio broadcasting systems deliver digital audio signals in such a way that is backward compatible with existing analog FM transmission. We present a channel error correction and detection system that is well-suited for use with audio source coders, such as the so-called perceptual audio coder (PAC), that have error concealment/mitigation capabilities. Such error mitigation is quite beneficial for high quality audio signals. The proposed system involves an outer cyclic redundancy check (CRC) code that is concatenated with an inner convolutional code. The outer CRC code is used for error detection, providing flags to trigger the error mitigation routines of the audio decoder, The inner convolutional code consists of so-called complementary punctured-pair convolutional codes, which are specifically tailored to combat the unique adjacent channel interference characteristics of the FM band. We introduce a novel decoding method based on the so-called list viterbi algorithm (LVA). This LVA-based decoding method, which may be viewed as a type of joint or integrated error correction and detection, exploits the concatenated structure of the channel code to provide enhanced decoding performance relative to decoding methods based on the conventional viterbialgorithm (VA). We also present results of informal listening tests and other simulations on the Gaussian channel. These results include the preferred length of the outer CRC code for 96-kb/s audio coding and demonstrate that LVA-based decoding can significantly reduce the error nag rate relative to conventional VA-based decoding, resulting in dramatically improved decoded audio quality. Finally, we propose a number of methods for screening undetected errors in the audio domain.
Binary arithmetic codes with forbidden symbols (named error correction arithmetic codes: ECAC) can be modeled as finite state machines and treated as variable length trellis codes. In this paper, a novel iterative joi...
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ISBN:
(纸本)9781424412211
Binary arithmetic codes with forbidden symbols (named error correction arithmetic codes: ECAC) can be modeled as finite state machines and treated as variable length trellis codes. In this paper, a novel iterative joint source channel decoding algorithm is proposed for decoding trellis based error correction arithmetic codes. Unlike the conventional iterative decoding algorithm, it is needless to use the additional check codes such as CRC during the encoding, the proposed algorithm utilizes the Monte Carlo methods to detect the error bit directly. Furthermore, the outer error detector can not only detect the error bits but also provide the probability of the error location to the inner error corrector so as to accelerate the decoding process. Experimental results show that the proposed algorithm has some significant performance improvements over some conventional decoding algorithms in terms of the symbol error rate, while the increased computational complexity can be accepted.
This paper presents a follow-up and improvement of our previous work on conflict detection and resolution (CDR) for unmanned aircraft "sense-and-avoid" (SA) applications. More specifically, we propose an ext...
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ISBN:
(纸本)9781509020126
This paper presents a follow-up and improvement of our previous work on conflict detection and resolution (CDR) for unmanned aircraft "sense-and-avoid" (SA) applications. More specifically, we propose an extension of our previous model predictive control formulation and algorithm that takes into account costs incurred by possible deviation from the desired destination so that the optimized solution produced by the algorithm naturally drives the aircraft towards its destination. Furthermore, we work out a solution to the SA problem in aircraft-weather conflicts within the multiple model framework of our approach. The performance of the proposed method is evaluated via simulation of a large variety of SA encounter scenarios, and compared with an existing method and with the optimal solution.
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