【作者】 张博；

【导师】 白宝明；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2013， 博士

【摘要】 提高网络信息容量,一方面需要增加网络的覆盖及提高信息的传输速率,另一方面用户密度的增加要求能有效解决干扰问题。近年来,MIMO、空时编码、机会调度、现代信道编码(Turbo码、LDPC码和Rateless码)、中继协作等技术的出现,在解决了第一类问题的同时加剧了小区内、小区间和网络间的干扰。因此,干扰日益成为制约提升通信系统性能的瓶颈,如何消除干扰带来的影响成为无线通信网络的研究重点。本文针对干扰信道的容量和传输策略问题进行研究,主要成果可概括如下：1)针对高斯干扰信道,提出了一种基于最大最小公平性的译码次序新算法。结合该算法,推导出和速率近似最大的速率分裂层数表达式。通过该译码次序新算法得到的和速率较已有贪婪算法得到的和速率有明显提高,并随着干扰强度的增加,其和速率逼近Sason提出的和速率内界。2)基于以上提出的译码次序算法,针对两用户高斯干扰信道提出了基于速率分裂的固定功率最优化分配算法。该系统中,每个发射端将所要传输的信息分成多层并行信息,通过固定功率最优化分配算法对每层信息赋予相应的功率,并将其叠加后进行传输；每个接收端采用之前提出的译码次序新算法对接收到的每层信息(包含有用信息和干扰信息)进行译码。两种算法的结合能够在不牺牲任何用户速率下提高系统的吞吐量,并在理想情况下能够进一步逼近Sason的和速率内界。3)通过分析Han-Kobayashi (HK)策略在多用户对称循环高斯干扰信道中的应用,提出了一种自适应奇偶对称速率分裂方案。具有低复杂度的该方案针对不同的信道条件设计出相应最优分裂系数和速率分裂方案。在高信噪比和一般信噪比环境下,自适应奇偶对称速率分裂方案得到的和速率在较大范围内明显大于由对称速率分裂方案和Etkin等人提出的速率分裂方案所得到的和速率,且在一般信噪比下能够逼近HK和速率内界。4)通过提出可达速率的内界和外界,进一步研究了HK策略在级联高斯Z干扰信道中的性能。通过增加级联高斯Z干扰信道的约束条件得出该信道的速率内界；参考Etkin等人针对两用户干扰信道提出的两种精灵辅助方案,得出级联高斯Z干扰信道的两条速率外界。通过推导速率内外界之差得出,在级联高斯Z干扰信道中利用HK策略所得到的速率内界距离信道容量约1bit。更多还原

【Abstract】 Two aspects are involved in increasing the capacity of network:one is to improvethe coverage of network as well as boost the data communication rate, and the other isto reduce the interference due to the high density of users. With the advent of MIMOtechnique, space-time code technique, opportunistic scheduling, modern channel coding(Turbo code, LDPC code and Rateless code) and relay cooperation technique, the frstproblem can be solved while aggravating the interference exiting in inter-cell, intra-cell andnetworks. Therefore, interference becomes the bottleneck of improving the property ofcommunication system. How to eliminate the impact of interference is the focus of wirelesscommunication research. This dissertation investigates the capacity and transmissionscheme of interference channel. The main results are summarized as follows:1) A novel algorithm for determination of decoding order for the Gaussian interferencechannel (GIC) is proposed based on max-min fairness. Based on the proposedalgorithm, an expression of the number of rate-splitting is derived for the sum-rate toapproach the maximum value. The proposed decoding order algorithm signifcantlyimproves the performance over the greedy algorithm on the two-user symmetricalGIC within a wide range of channel coefcients, and the sum-rate of the proposedscheme can approach the inner bound of Sason as increasing the interference factor.2) Based on the above decoding order algorithm, an optimal power allocation algo-rithm for two-user Gaussian symmetrical interference channel is proposed. In thissystem, each transmitter splits its information into multiple layers assigned withthe power which determined by optimal power allocation algorithm and transmitsthe superposition of those layers, and each receiver decodes the message from alllayers of the two users by the proposed decoding order algorithm. Combining thetwo algorithms can improve the sum-rate of the two-user interference channel with-out sacrifcing the rate of either user, and make a signifcant improvement of theperformance over that of equal power allocation. In the ideal case, the sum-rateeven approaches the inner bound of Sason.3) By analysing the performance of Han-Kobayashi (HK) strategy in multi-user sym-metric Gaussian cyclic interference channel, an adaptive odd-even symmetric rate-splitting scheme is proposed. With low complexity, the proposed scheme designsthe optimal split ratio and the rate-splitting’s scheme according to various channelconditions. In a large range of transmitted power and interference factor, the sum-rate achieved using the proposed scheme is higher than that using the symmetric scheme and the scheme proposed by Etkin et al. in high SNR and general SNRregimes. The sum-rate of the proposed scheme can also approach the inner boundof HK scheme in general SNR regimes.4) The HK strategy is further studied on cascade Gaussian Z interference channel byproposing a new inner bound and two new outer bounds of achievable rate. The newinner bound is proposed by adding some constraints on this channel. According tothe method proposed by Etkin et al, the new outer bounds are proposed by givingextra side information to the receivers. We show that a very simple and explicitHK type scheme can achieve to about a single bit per second per hertz (bit/s/Hz)of the capacity for all values of the channel parameters.更多还原