We analyze the performance of channel coding diversity with general decoding metrics in terms of the generalized mutual information (GMI). We show that the GMI of the diversitychannel is less than or equal to the bau...
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We analyze the performance of channel coding diversity with general decoding metrics in terms of the generalized mutual information (GMI). We show that the GMI of the diversitychannel is less than or equal to the baud-rate weighted sum of the component GMIs;and equality is achieved only in special cases. We then focus on bit-interleaved coded modulation (BICM) schemes and demonstrate the applicability of our findings by an example of hybrid free-space optical and radio-frequency (FSO-RF) communication.
A key challenge in the design of real-time wireless multimedia systems is the presence of fading coupled with strict delay constraints. A very effective answer to this problem is the use of diversity achieving techniq...
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A key challenge in the design of real-time wireless multimedia systems is the presence of fading coupled with strict delay constraints. A very effective answer to this problem is the use of diversity achieving techniques to overcome the fading nature of the wireless channels caused by the mobility of the nodes. The mobility of the nodes gives rise to the need of cooperation among the nodes to enhance the system performance. This paper focuses on comparing systems that exhibit diversity of three forms: source codingdiversity, channel coding diversity, and user cooperation diversity implemented through multihop or relay channels with amplify-and-forward or decode-and-forward protocols. Commonly used in multimedia communications, performance is measured in terms of the distortion exponent, which measures the rate of decay of the end-to-end distortion at asymptotically high signal-to-noise ratio (SNR). For the case of repetition coding at the relay nodes, we prove that having more relays is not always beneficial. For the general case of having a large number of relays that can help the source using repetition coding, the optimum number of relay nodes that maximizes the distortion exponent is determined in this paper. This optimum number of relay nodes will depend on the system bandwidth as well as the channel quality. The derived result shows a trade-off between the quality ( resolution) of the source encoder and the amount of cooperation ( number of relay nodes). Also, the performances of the channel coding diversity-based scheme and the source codingdiversity-based scheme are compared. The results show that for both relay and multihop channels, channel coding diversity provides the best performance, followed by the source codingdiversity.
This paper address the application of multiple repetition channels performed in Bluetooth system. The achieved performance of redundant transmissions over several channels is considered as approach for data reliabilit...
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ISBN:
(纸本)0889865639
This paper address the application of multiple repetition channels performed in Bluetooth system. The achieved performance of redundant transmissions over several channels is considered as approach for data reliability improvement. Taking into account the error correction capabilities, the frame error rates for all packet types have been compared. We also provided some theoretical and numerical considerations for the case of several redundant independent channels. Finally, an estimation of the expected performance gain is given.
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