Luby transform （LT） codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping （FH） communication systems. A decoding scheme for joint erasures of severely jammed symbols and er...Luby transform （LT） codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping （FH） communication systems. A decoding scheme for joint erasures of severely jammed symbols and error correction is proposed. If an uncorrectable error is detected, the receiver erases the jammed symbols and uses incremental redundancy to increase the error-correcting capability. The performance of LT codes, under power-oppressive partial band noise jamming （ PB- N J） with the additive white Gaussian noise （AWGN）, is evaluated via simulation. Even if the jam- mer spreads its high power over half of the hopping bandwidth, LT codes are shown to achieve a tar- get bit error probability of 10 -5, demonstrating their effectiveness as high-performance codes to im- prove the ability of FH systems to combat varying partial band noise jamming.展开更多
To deal with a sharp increase in transmission energy consumption due to the presence of a large number of secondary users( SUs),an energy-efficient cooperative spectrum sensing results transmission scheme is proposed ...To deal with a sharp increase in transmission energy consumption due to the presence of a large number of secondary users( SUs),an energy-efficient cooperative spectrum sensing results transmission scheme is proposed for cognitive radio systems. First,a cluster-based structure is introduced into the sensing results transmission scheme to reduce the transmission power. Then,the centralized sensing results transmission model is employed,and the non-fixed code rate Luby transform( LT)code is selected as the channel coding since its code rate can dynamically adapt to channel conditions and therefore avoid unnecessary redundancy in the transmission power.Furthermore,an improved optimal degree distribution( ODD)is designed for the LT code. The simulation results show that the choice of the appropriate parameters in degree distribution is very helpful for the LT code to achieve a promising performance. The ODD with optimized parameters can achieve more than 2 d B performance gain than other typical degree distributions when the bit error rate( BER) is 10-3. The energy consumption of the proposed scheme is not only at least71. 4% lower than that of the non-coding system,but also lower than that of the convolutional coding system with different code rates. Meanwhile, the energy consumption can be further reduced in the case that a suitable clustering method is selected.展开更多
An effective Luby transform （LT） encoding algorithm based on short cycle elimination is proposed to improve decoding probabilities of short length LT codes. By searching the generator ma- trix, some special encoded ...An effective Luby transform （LT） encoding algorithm based on short cycle elimination is proposed to improve decoding probabilities of short length LT codes. By searching the generator ma- trix, some special encoded symbols are generated by the encoder to effectively break the short cycles that have negative effect on the performance of LT codes. Analysis and numerical results show that by employing the proposed algorithm, the encoding complexity decreases and the decoding probabili- ties improve both in binary erasure channels （BECs） and additive white gauss noise （AWGN） chan- nels.展开更多
针对空间信息网络(Space Information Network,SIN)节点存储资源严重受限及存储可靠性问题,该文提出一种基于LT(Luby Transform)码的分布式存储策略(Distributed Storage Strategy based on LT codes,DSSLT)。采用定向随机漫步机制,使...针对空间信息网络(Space Information Network,SIN)节点存储资源严重受限及存储可靠性问题,该文提出一种基于LT(Luby Transform)码的分布式存储策略(Distributed Storage Strategy based on LT codes,DSSLT)。采用定向随机漫步机制,使得源数据包能够更快地遍历整个网络。在信息估计阶段利用基于ID的估计方法进行网络全局信息估计,使所有节点快速获得网络全局信息。合理的数据包选择机制使得最终编码度分布趋于期望的度分布。分析和仿真结果表明,与具有代表性的分布式存储策略相比,该方法大幅度减少了数据包传输时的随机漫步步长,同时提高了译码性能,简单易行。展开更多
基金Supported by the National Nature Science Foundation of China(61072048)
文摘Luby transform （LT） codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping （FH） communication systems. A decoding scheme for joint erasures of severely jammed symbols and error correction is proposed. If an uncorrectable error is detected, the receiver erases the jammed symbols and uses incremental redundancy to increase the error-correcting capability. The performance of LT codes, under power-oppressive partial band noise jamming （ PB- N J） with the additive white Gaussian noise （AWGN）, is evaluated via simulation. Even if the jam- mer spreads its high power over half of the hopping bandwidth, LT codes are shown to achieve a tar- get bit error probability of 10 -5, demonstrating their effectiveness as high-performance codes to im- prove the ability of FH systems to combat varying partial band noise jamming.
基金The National Natural Science Foundation of China(No.61771126)the Foundation of Graduate Innovation Center in NUAA(No.kfjj20170402)
文摘To deal with a sharp increase in transmission energy consumption due to the presence of a large number of secondary users( SUs),an energy-efficient cooperative spectrum sensing results transmission scheme is proposed for cognitive radio systems. First,a cluster-based structure is introduced into the sensing results transmission scheme to reduce the transmission power. Then,the centralized sensing results transmission model is employed,and the non-fixed code rate Luby transform( LT)code is selected as the channel coding since its code rate can dynamically adapt to channel conditions and therefore avoid unnecessary redundancy in the transmission power.Furthermore,an improved optimal degree distribution( ODD)is designed for the LT code. The simulation results show that the choice of the appropriate parameters in degree distribution is very helpful for the LT code to achieve a promising performance. The ODD with optimized parameters can achieve more than 2 d B performance gain than other typical degree distributions when the bit error rate( BER) is 10-3. The energy consumption of the proposed scheme is not only at least71. 4% lower than that of the non-coding system,but also lower than that of the convolutional coding system with different code rates. Meanwhile, the energy consumption can be further reduced in the case that a suitable clustering method is selected.
基金Supported by China Mobile Research Institute and China National S&T Major Project(2010ZX03003-003)
文摘An effective Luby transform （LT） encoding algorithm based on short cycle elimination is proposed to improve decoding probabilities of short length LT codes. By searching the generator ma- trix, some special encoded symbols are generated by the encoder to effectively break the short cycles that have negative effect on the performance of LT codes. Analysis and numerical results show that by employing the proposed algorithm, the encoding complexity decreases and the decoding probabili- ties improve both in binary erasure channels （BECs） and additive white gauss noise （AWGN） chan- nels.
文摘针对空间信息网络(Space Information Network,SIN)节点存储资源严重受限及存储可靠性问题,该文提出一种基于LT(Luby Transform)码的分布式存储策略(Distributed Storage Strategy based on LT codes,DSSLT)。采用定向随机漫步机制,使得源数据包能够更快地遍历整个网络。在信息估计阶段利用基于ID的估计方法进行网络全局信息估计,使所有节点快速获得网络全局信息。合理的数据包选择机制使得最终编码度分布趋于期望的度分布。分析和仿真结果表明,与具有代表性的分布式存储策略相比,该方法大幅度减少了数据包传输时的随机漫步步长,同时提高了译码性能,简单易行。
