Optimum Codes for FFH/BFSK Receivers with Self-Normalization Combining and Hard Decision Decoding in Fading Channels


Book Description

The application of forward error correction coding to a fast frequency-hopped binary frequency-shift keying (FFH/BFSK) noncoherent receiver with self-normalization combining under broadband and partial-band jamming is discussed in this thesis. The performance of the receiver is examined when data are encoded using Reed-Solomon codes, convolutional codes, and concatenated Reed-Solomon and convolutional codes, all with hard decision decoding. The effects of the transmission channel is considered, and results are derived for a Rayleigh fading channel and Ricean fading channels with several different ratios of direct-to-diffuse signal power. Only frequency nonselective, slowly fading channels are considered. The combination of diversity and forward error correction coding is found to improve the performance of the receiver in the presence of both broadband and partial-band jamming and optimum codes for each coding scheme are also discussed.




Optimum Codes for FFH


Book Description

The application of forward error correction coding to a fast frequency-hopped binary frequency-shift keying (FFH/BFSK) noncoherent receiver with self-normalization combining under broadband and partial-band jamming is discussed in this thesis. The performance of the receiver is examined when data are encoded using Reed-Solomon codes, convolutional codes, and concatenated Reed-Solomon and convolutional codes, all with hard decision decoding. The effects of the transmission channel is considered, and results are derived for a Rayleigh fading channel and Ricean fading channels with several different ratios of direct-to-diffuse signal power. Only frequency nonselective, slowly fading channels are considered. The combination of diversity and forward error correction coding is found to improve the performance of the receiver in the presence of both broadband and partial-band jamming and optimum codes for each coding scheme are also discussed.




Proceedings


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Index to IEEE Publications


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Performance of FFH/BFSK Systems with Convolutional Coding and Soft Decision Viterbi Decoding Over Rician Fading Channels with Partial-Band Noise Interference


Book Description

An error probability analysis of a communications link employing convolutional coding with soft decision viterbi decoding implemented on a fast frequency hopped, binary frequency shift keying (FFH(BFSK) spread spectrum system is performed. The signal is transmitted through a Rician fading channel with partial band noise interference. The receiver structures examined are the conventional receiver with no diversity, the conventional receiver with diversity and the assumption of perfect side information, and the self normalized combining receiver with diversity. The self normalized receiver minimizes the effects of hostile partial band interference, while diversity alleviates the effects of fading. It is found that with the implementation of soft decision viterbi decoding the performance of the self normalized receiver is improved dramatically for moderate coded bit energy to partialband noise power spectral density ratio (EbNI). Coding drives the jammer to a full band jamming strategy for worst case performance. Nearly worst case jamming occurs when barrage jamming is employed and there is no diversity even in cases where there is very strong direct signal. Performance improves as the constraint length of the convolutional code is increased. For the most powerful convolutional codes, performance is seen to degrade slightly with increasing diversity except in instances of a very weak direct signal. Also, soft decision decoding is found to be superior to hard decision decoding by approximately 4 dB at moderate Eb/NI.




Error Probabilities of FFH/BFSK with Noise Normalization and Soft Decision Viterbi Decoding in a Fading Channel with Partial-band Jamming


Book Description

An error probability analysis of a communications link employing convolutional coding with soft decision Viterbi decoding implemented on a fast frequency-hopped, binary frequency-shift keying (FFH/BFSK) spread spectrum system is performed. The signal is transmitted through a frequency nonselective, slowly fading channel with partial-band jamming. Noise normalization combining is employed at the receiver to alleviate the effects of partial-band jamming. The received signal amplitude of each hop is modeled as a Rician process, and each hop is assumed to fade independently. It is found that with the implementation of soft decision Viterbi decoding that the performance of the receiver is improved dramatically when the coded bit energy to partial-band noise power spectral density ratio (Eb/N1) is greater than 10dB. At higher Eb/ N1, the asymptotic error improves dramatically and varies from 10 to the -6 power to 10 to the -12 power depending on the constraint length (v), number of hops/bit (L), and the strength of the direct signal (alpha2/2alpha2). In addition, nearly worst case jamming occurs when the jammer uses a full band jamming strategy, even when L=l and there is a very strong direct signal (alpha2/2alpha 2= 100). Due to noncoherent combining losses, when the hopper bit ratio is increased, there is some degradation at moderate Eb/N1. Furthermore, when a stronger code is used (i.e., the constraint length is longer), performance improves, especially for high Eb/N1 where the asymptotic error is reduced. Finally, soft decision decoding improves performance over hard decision decoding from 4 to 8dB At moderate Eb/N1 depending on the code rate and with a much lower asymptotic error at high Eb/N1.







Science Abstracts


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Multi-Dimensional Modulation Codes for Fading Channel


Book Description

Some new codes are presented which have good performance on Rician fading channel with small decoding complexities. A new M-way partition chain is proposed for the L x MPSK (L less than or equal to M) signal set which maximizes the intra-set distance of each subset at each partition level. Based on this partition chain, a class of asymptotical optimum codes was found. For M = 4, these codes have both large symbol distances and product distances. Multi-level coding scheme allows to construct a code by hand such that the code meets some desired parameters, e.g., symbol distance, product distance, etc. In design of a multi-level code, all factors were considered which affect the performance and complexity of the code, such as, the decoding scheme, decoding complexity, and performance under the decoding scheme, e.g., if the multi-stage decoding scheme is used, the performance degradation due to the suboptimum decoding is taken into consideration. The performance for most of the presented codes was simulated on Rayleigh fading channel, and the results show that these codes have good performance with small decoding complexities. Lin, Shu and Wu, Jiantian Unspecified Center NAG5-931...




Principles of Mobile Communication


Book Description

Principles of Mobile Communication provides an authoritative treatment of the fundamentals of mobile communications, one of the fastest growing areas of the modern telecommunications industry. The book stresses the fundamentals of mobile communications engineering that are important for the design of any mobile system. Less emphasis is placed on the description of existing and proposed wireless standards. This focus on fundamental issues should be of benefit not only to students taking formal instruction but also to practising engineers who are likely to already have a detailed familiarity with the standards and are seeking to deepen their knowledge of this important field. The book stresses mathematical modeling and analysis, rather than providing a qualitative overview. It has been specifically developed as a textbook for graduate level instruction and a reference book for practising engineers and those seeking to pursue research in the area. The book contains sufficient background material for the novice, yet enough advanced material for a sequence of graduate level courses. Principles of Mobile Communication treats a variety of contemporary issues, many of which have been treated before only in the journals. Some material in the book has never appeared before in the literature. The book provides an up-to-date treatment of the subject area at a level of detail that is not available in other books. Also, the book is unique in that the whole range of topics covered is not presently available in any other book. Throughout the book, detailed derivations are provided and extensive references to the literature are made. This is of value to the reader wishing to gain detailed knowledge of a particular topic.