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双语推荐：信道编码

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多天线空时预编码技术利用信道状态信息能够有效地改善无线通信系统性能与吞吐量，成为未来无线移动通信领域研究的热点。根据发射端利用信道状态信息情况，预编码技术可分为完全信道预编码技术和部分信道预编码技术。文章主要研究了多用户 MIMO 多载波无线通信系统中空时预编码技术，研究了多用户 MIMO 多载波系统中空时预编码技术，文中还重点对基于码本的多用户 MIMO 预编码进行了研究。
Multi-antenna space-time pre-coding at the transmitter as a modern signal processing technology can use im -perfect channel state information or partial channel state information to improve the system capacity or reduce bit error rate , thus becoming the research hot in wireless mobile communication .According to the transmitter using the channel state infor-mation case ,pre-coding techniques can be divided into imperfect channel pre-coding techniques and partial channel pre-coding techniques .In this paper ,the Space-Time Pre-coding for multi-user MIMO multi-carrier systems are studied ,multi-user MI-MO precoding based on codebook is focused on ,a limited feedback precoding method for multi-user MIMO-OFDM based on codebook perturbation is proposed .

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量子编码定理证明信道在没有辅助资源的情况下其量子容量等于规整化相干信息的最大值。一般泡利信道是最普遍使用的信道模型,其量子容量目前无法准确计算,只能用多信道相干信息去逼近。本文应用量子图态级联编码,得到一般泡利信道在该编码输入下的多信道相干信息的公式,能够有效计算一般泡利信道量子容量的逼近值和信道传输量子信息的噪声容限。计算速度比Monte Carlo算法提高三个数量级。
Quantum capacity of a channel is the maximal quantum information that can be reliably transmitted .Quantum coding theorem shows that quantum capacity of a channel without additional resources is equal to the regularized coherent information .The generic Pauli channel is the most popular model in practice ,and its quantum capacity cannot be evaluated exactly ,but rather can only be approached by using multichannel coherent information .In this paper ,we used concatenate graph state code to obtain formulae of coherent information for generic Pauli channels ,by which we could find the approach value of quantum capacity and the noise tolerance of the channel efficiently .

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网络编码技术可以提高网络吞吐量和传输性能,均衡网络负载。在无线传感器网络中,应用网络编码和信道编码联合编码技术可以降低节点数据处理复杂度,大幅提升系统整体性能。基于传统网络编码模型,在节点中加入数据调制功能,可以实现网络编码和信道编码的联合编码,信道编码则采用各方面性能较好的Turbo码和LDPC码。结果表明,在10-4误码率下,联合编码方案的信噪比相比于传统编码方案有1.5 dB的节省。
Network coding technology can not only improve the throughput and transmission efficiency of the network system,but also make the load more balanced. By employing the joint coding of network coding and channel coding in the Wireless Sensor Network,it can reduce the complexity of data processing in the node and hugely promote the performance of the whole system. Based on the traditional netwok coding model, joint coding can be realized by employing the modulation in the node. Turbo codes and LDPC codes are among those best performing codes and they have some unique advantages so are preferred in the system. The result shows that under the same circumstance of bit error rate 10-4 ,the signal to noise ratio can be saved by 1. 5 dB.

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研究了室内密集立体覆盖非对称、多向中继自组织网络中利用节点先验信息，在中继端联合信道编码、网络编码、自适应调制等技术进行干扰消除的传输方案。重点针对单中继两用户互传、单中继多对用户互传模型的下行信道，分别提出了自适应-网络编码调制、信道编码-网络编码2种联合设计方案。具体分别提出了变功率-速率自适应网络编码相移键控调制（NC-PSK）方案和联合网络-脏纸编码方案，并推导出2种方案下行广播信道可达速率的闭式解。仿真结果表明2种方案能够提高中继网络的频谱利用率，同时有效对抗信道衰落和干扰。
In this paper, we investigate interference elimination transmission schemes for asymmetric, multi-way relaying of the 3-dimensional dense coverage self-organized network, relying on the combination of channel coding, network coding, adaptive modulation techniques with a priori knowledge at the relay node. We propose two transmission designs for the downlink of two-user Two-way Relay Channel and Pairwise-users Multi-way Relay Channel, based on the combination of the Adaptive Modulation/Channel Coding and Network Coding Technique. We also proposed a variable-power and rate-adaptive NC-PSK scheme and Joint Network Coding-Dirty Paper Coding scheme. We further derive the closed-form solutions for the achievable rate of the two broadcast channels. Simulation results show that our proposed schemes increase spectral efficiency, effectively handle channel fading and interference.

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基于信道编码的容错冗余特性，文章提出了一种利用BCH码实现信息隐藏的方法。在不改变载体的信源编码结构的前提下，利用伪随机序列调整嵌入步长，将秘密信息当做噪声随机地嵌入到载体的信道编码码流中，避免了传统信息隐藏方法中秘密信息嵌入位置集中的问题。理论分析和实验结果表明，当载体一定时，信道误码率越高，隐藏容量越小；载体信道编码的信息码长越短，隐藏容量越大；载体信道编码的纠错能力越强，隐藏容量越大。实验结果还表明，隐藏信息对载体的恢复并无显著影响。
Due to the fault-tolerant redundancy introduced by the channel coding, a method for information hiding based on BCH coding is proposed. The messages are embedded to the coded carrier based on a pseudo-random sequence, while no changes are made to the source code of the carrier. By this method, the messages are embedded to the carrier just like random noise, which makes it avoid the problem of non-uniformly embedding in traditional information hiding methods. Analysis and experiments show the higher the bit error rate of the channel is, the lower the hiding capacity is; the shorter the length of the information bits in the channel coding of the carrier is, the higher the hiding capacity is; the stronger the error correcting capability of the channel coding is, the higher the hiding capacity is. Moreover, experiments show the embedded data has little influence on the restored carrier.

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在水声通信中,由于通信系统的复杂度和系统能耗的限制,以及水声信道的不稳定性给水声通信的可靠性和高效性带来很大的挑战;采用联合信源信道编码算法可以实现可靠的水声通信;目前,在水声通信中较少涉及联合信源信道的算法;文中提出基于LZW(Lempel-Ziv & Welch)和RS (Reed-Solomon)编码的联合信源信道编码算法,对比分析了RS对信源进行均等保护编码性能;结合实际应用环境,LZW信源编码算法实现简单,而RS编码又能纠正连续的的突发错误,所以适合于信道可靠性不高的水声信道;仿真结果表明,在不增加设备复杂度和系统开销的情况下,此算法的无损压缩率为2∶1～3∶1,并且在信噪比为0～-3dB是能达到很好的重构性能.
In the underwater acoustic communication,due to the complexity of the communication and power of the underwater source equipment is limited as well as the unreliability of the acoustic channel; the underwater acoustic communication is a challenge task.Joint source and channel coding algorithm can achieve reliable underwater acoustic communication.Currently,the joint source-channel algorithm is less applied to underwater acoustic communication.Joint Source Channel Lempel-Ziv-Welch (LZW) coding technique is proposed for the deep water acoustic communication system using in this paper and comparative analysis of the performance of the RS are subject to equal protection of source coding.Combined with practical application environment,LZW source coding algorithm is simple to implement,RS coding can correct continuous burst error,and it is suitable for underwater acoustic channel because its reliability is not high.Simulation results show that this algorithm for lossless compression ratio of

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介绍了一种长距离无线数字通信中的信道编码设计方案。为改善通信质量,采用了(255,233)RS编码+(8,255)交织+(2,1,7)卷积编码这一信道编码方式。MATLAB仿真结果表明,该级联码能有效降低数字通信系统的误码率,在无线数字通信领域中有着很好的应用前景。
This paper introduces a method of designing the channel coding on long-distance wireless digital communication, in order to enhance the quality of communication,(255,233)RS code and(2,1,7)convolu-tion code are cascaded by (8,255) inter-leaver. The MATLAB simulation result shows that cascaded code will be widely used in wireless digital communication region because of its low error rate.

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提出一种基于网络编码的802.11 DCF信道接入机制（NCA-DCF）。采用冲突避免的主动确认策略,使相应节点形成编码意识,通过编码包的机会转发,提高数据包传输效率,结合无线网络编码的特性,运用马尔科夫链模型对NCA-DCF进行数学建模。分析结果表明,与传统的DCF信道接入机制相比,NCA-DCF不仅可以避免节点发送分组的碰撞,有效提高信道利用率,而且能够明显提高全网吞吐量。
This paper proposes a Network Coding-aware 802.11 Distributed Coordination Function(NCA-DCF) channel access mechanism. A Proactive Acknowledgement(PACK) strategy with collision avoidance is introduced to deploy a coding-aware scheme for each node. Through opportunistic forwarding, NCA-DCF can enhance the reliability in a single transmission. It develops a Markov chain model to characterize the NCA-DCF mechanism, in consideration of the characteristics of wireless network coding. Analysis result shows that NCA-DCF can avoid collision and improve channel utilization rate, it achieves significant performance improvement.

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为了使协作中继通信系统在有效性和可靠性之间获得较好的折中,提出一种新型的联合多元信道编码调制-网络编码一体化设计方案,即多元低密度奇偶校验码(low-density parity-check codes,LDPC)-比特交织编码调制(bit interleaved coded modulation,BICM)-网络编码方案。该方案将多元信道编码调制技术与网络编码技术在中继节点相结合,译码时考虑到序列的相关性,采用联合迭代相关译码算法,在保证系统的有效性的同时,提高了系统的可靠性。仿真结果表明:联合多元信道编码调制-网络编码方案与无中继系统、信源不相关的多元LDPC-BICM系统相比,均可获得较好编码增益,大幅度提高了系统的可靠性。
In order to make the cooperative relay communication system achieve good tradeoff between effectiveness and reliability, a novel joint Q-ary channel coding modulation-network coding integration design program has been proposed, specifically the Q-ary low-density parity-check codes ( LDPC )-bit interleaved coded modulation ( BICM)-network coding scheme. This scheme combines Q-ary channel coding modulation technology with network coding technology in the relay node, and takes into account the correlation of the sequence of source nodes. A joint iterative correlation decoding algorithm was used to ensure the effectiveness of the system and to improve the relia-bility of the system when decoding. Simulation results demonstrate that, in comparison with the Q-ary LDPC-BICM system without a relay system and uncorrelated signal source, the scheme proposed by this paper can obtain better coding gains and greatly improve the reliability of the system.

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针对空时相关的MIMO信道,提出了一种新颖的Huffman空时联合有限反馈预编码方法,提高了系统性能,并减少了反馈量。从信道的空间相关性出发,推导了迫零准则下预编码的构成,从而设计了一种旋转量化码本,减小了空间相关性对系统性能的影响。另外,针对信道的时间相关性,利用基于邻域的有限反馈来降低慢衰落信道的反馈量。同时,由于领域内各码字被选中的概率不同,可以利用Huffman编码进一步减少反馈量。
For the MIMO channels with space correlation and time correlation, a novel joint space-time Huffman limited feedback precoding scheme was proposed which improves the system performance and reduces the amount of feedback. Based on space correlation, the precoding structure under zero-forcing (ZF) criterion was derived and the rotating quan-tization codebook was designed which reduces the effect of space correlation on system performance. In addition, in view of time correlation of channels, the scheme reduces the feedback data of channel state information (CSI) in the slow fad-ing channel by using neighborhood-based limited feedback. Due to different probabilities of codewords in the neighbor-hood, Huffman coding was adopted to further reduce the amount of feedback.

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