In this letter, we investigate the coding overhead in decentralized coded caching scheme. Firstly, a unified framework is presented to analyze the incurred coding overhead for two header formats. Secondly, the coding ...
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In this letter, we investigate the coding overhead in decentralized coded caching scheme. Firstly, a unified framework is presented to analyze the incurred coding overhead for two header formats. Secondly, the coding overhead analysis of three decentralized schemes, including the Maddah-Ali-Niesen (MAN) scheme (Maddah-Ali and Niesen, 2015), the coded prefetching scheme (Tian and Chen, 2018), and the reduced subpacketization scheme (Jin et al., 2016), is presented to unveil that, the overhead can lead to performance loss. Our analysis shows that the second format is always preferable for any uncoded and binary coded packets, and the coding overhead increases with the increase in subpacketization, while the degradation rate of transmission payload decreases exponentially. It is demonstrated numerically that, for the system with small number of users and moderate sized files, the coding overhead tends to be negligible in the uncoded and binary coded schemes;however, it becomes significant for non-binary coded schemes, especially when the file size is not sufficiently large. These results suggest the importance of choosing an efficient header format in specific coded caching application, in particular for non-binary schemes.
Network coding is expected to improve throughput performance of multihop wireless networks. However, the end-to-end throughput is significantly affected by the coding overhead. This paper considers the impact of the c...
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Network coding is expected to improve throughput performance of multihop wireless networks. However, the end-to-end throughput is significantly affected by the coding overhead. This paper considers the impact of the coding overhead on throughput performance for multihop wireless networks. Focusing on a three-node chain topology, we model an intermediate node as a single-server queueing system with two buffers. We construct a discrete-time Markov chain on the epochs where one of nodes starts a packet transmission, analyzing the per-flow throughput. The analysis is validated by simulation. Numerical examples show that a long processing time for coding significantly degrades the per-flow throughput. (C) 2012 Elsevier B.V. All rights reserved.
This paper describes a packet-based overhead-reduced (OR) key coding technique for a high-speed serial interface. The 8B10B code is a de facto standard coding technique in the application but its bit-overhead is 25%. ...
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This paper describes a packet-based overhead-reduced (OR) key coding technique for a high-speed serial interface. The 8B10B code is a de facto standard coding technique in the application but its bit-overhead is 25%. The proposed key coding technique is to reduce the coding overhead and still provides enough bit transition to facilitate clock and data recovery in the receiver. After a key pattern is generated from a certain data stream, input data are encoded and framed as packets along with the generated key for transmission. The packets are transmitted and then decoded as original data in the receiver. Using the proposed coding scheme, 4-, 6-, and 8-bit key coding systems are designed and compared. When a 6-bit key coding encoder/decoder is tested, a packet is composed of a 6-bit OR key header followed by 30 encoded sub-packets, in which each sub-packet has a 6-bit data. In the 6-bit case, the bit overhead is only 3.33% and the maximum continuous run length is 10 bits. To control the running disparity for the AC coupling interface, a logic for selecting the optimal key is implemented to keep the running disparity as low as possible. The running disparity of the encoded data with 6-bit key code is controlled within +/-12.
We can encode rare events with an overhead of about 1.56 bits/event. The contribution of the overhead to the total length of the code is negligible. The encoding and decoding time counted in operations over bits per b...
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We can encode rare events with an overhead of about 1.56 bits/event. The contribution of the overhead to the total length of the code is negligible. The encoding and decoding time counted in operations over bits per bit of the code does not depend on the number of appearances of the events. We present also algorithms of the same speed which enumerate the pyramid cubic lattices with an overhead of about 1.56 bits/dimension. The overhead is the price for reaching the ultimate (to within a constant factor) encoding and decoding speed.
Based on the idea of unequal error protection, a novel error-correcting scheme for variable-length codes (VLC) is proposed. The synchronisation information in the VLC-coded bitstream acquires more protection without i...
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Based on the idea of unequal error protection, a novel error-correcting scheme for variable-length codes (VLC) is proposed. The synchronisation information in the VLC-coded bitstream acquires more protection without increasing coding overhead. Simulation results exhibit considerable gains of the proposed scheme over the traditional error-correcting scheme under a wide range of channel conditions.
Wireless Sensor Networks (WSNs) can be successfully applied in a wide range of applications. Efficient data dissemination is a fundamental service which enables many useful high-level functions such as parameter recon...
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ISBN:
(纸本)9781457705137
Wireless Sensor Networks (WSNs) can be successfully applied in a wide range of applications. Efficient data dissemination is a fundamental service which enables many useful high-level functions such as parameter reconfiguration, network reprogramming, and etc. Many current data dissemination protocols employ network coding techniques to deal with packet losses. The coding overhead, however, becomes a bottleneck in terms of dissemination delay. We exploit the concurrency ability of sensor nodes and propose MT-Deluge, a multi-threaded design of a coding-based data dissemination protocol. By separating the coding and radio operations into two threads and carefully scheduling their executions, MT-Deluge shortens the dissemination delay effectively. An incremental decoding algorithm is employed to further improve MT-Deluge's performance. Experiments with 20 TelosB motes on three representative topologies show that MT-Deluge shortens the dissemination delay by 37.6%similar to 48.6% compared to a typical data dissemination protocol while keeping the merits of loss resilience.
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