同时同频全双工系统谱效和能效优化
发布时间：2019-06-02 20:19
【摘要】：随着移动设备的迅速普及,日益增长的数据流量需求给无线通信系统带来了巨大的挑战。为了提高无线网络的容量,同时同频全双工(in-band full-duplex)通信技术被提出来,并且越来越受到学术界和工业界的关注。全双工(FD)通信技术允许用户在同一频段内同时发射和接收信号,因此有可能使通信链路的容量加倍。全双工通信最大的挑战是设备本身产生的自干扰(SI)。目前已经有三类自干扰消除技术:传输路径压制、模拟域消除和数字域消除。联合使用这三类自干扰消除方法,可以将残存自干扰(RSI)压制到一个足够低的强度。本文研究的是一个实际的全双工通信系统:基站(BS)没有空间的限制,可以配备复杂的自干扰消除硬件,从而拥有全双工通信的能力;而用户终端由于受自身尺寸和成本的限制,只能进行传统的半双工(HD)通信。在这样的系统中,一个上行用户和一个下行用户可以配对进行全双工通信。这种通信方式存在两种类型的干扰:基站处的残存自干扰和下行用户处的同信道干扰(CCI)。本文首先研究了如何提升频分全双工网络中的吞吐量。为了尽可能地提高网络吞吐量,我们进一步引入机会式干扰消除(OIC)技术来消除同信道干扰。最大化网络吞吐量的问题可以建模为联合功率控制、信道分配和用户配对的问题。由于存在整数变量,该问题是一个NP-hard的问题。为了求解该问题,我们提出了一种低计算复杂度的启发式算法。仿真结果表明:相对于半双工网络,该算法具有全双工增益、多用户分集增益以及OIC增益;并且全双工通信的性能取决于残存自干扰的强度。我们研究了时分全双工网络中的最大化吞吐量问题。该问题是一个非凸问题,无法获得最优解。我们提出了一种基于凹凸过程(CCCP)的次优算法来求解该问题。为了进一步降低计算复杂度,我们提出了一种不需要迭代的启发式算法。仿真结果表明,与频分全双工网络类似,应用该方法的时分全双工网络具有全双工增益和多用户分集增益,并且全双工通信的性能取决于残存自干扰的强度。我们研究了全双工网络的功率效率。在非完全信道状态信息(CSI)的情况下,我们给出了全双工用户发射功率的可行域,并且给出了最优发射功率的数值解。在高信噪比情况下,我们进一步推导了最优发射功率的闭式解。基于这个闭式解,我们提出了全双工通信与半双工通信功率效率的一个比较准则。最后,我们研究了全双工网络中能量效率(EE)与频谱效率(SE)的折中问题。由于自干扰消除技术尚未完全成熟,我们分别针对两种残存自干扰模型——固定残存自干扰模型和线性残存自干扰模型——进行了研究。在这两种残存自干扰的假设下,我们比较了全双工通信和半双工通信的能量效率与频谱效率折中的问题,并分别提出了全双工通信优于半双工通信的必要条件。针对固定残存自干扰模型,在只研究一对用户的情况下,我们证明了用户的总发射功率是频谱效率的严格凸函数。基于这个凸性,我们继续证明了能量效率是频谱效率的拟凹函数。随后,我们继续将能量效率与频谱效率的拟凹性推广到多个用户的场景,并且提出了一种寻找全局最优能量效率的算法。针对线性残存自干扰模型,由于干扰情况更加复杂,无法求取最优解,我们提出了一种启发式算法。该算法通过将原问题分解为功率控制和用户配对两个子问题进行求解。仿真分析验证了我们的理论推导和提出方法的有效性。
[Abstract]:With the rapid spread of mobile devices, the increasing demand for data traffic presents a great challenge to the wireless communication system. In order to improve the capacity of the wireless network, simultaneous on-band full-duplex communication technology is proposed, and more and more attention is paid to the academic and industrial circles. A full-duplex (FD) communication technology allows a user to transmit and receive signals simultaneously within the same frequency band, and thus it is possible to double the capacity of the communication link. The biggest challenge for full-duplex communication is the self-interference (SI) generated by the device itself. There are three types of self-interference cancellation technologies: transmission path suppression, analog domain cancellation, and digital domain elimination. The combined use of these three types of self-interference cancellation methods can suppress the residual self-interference (RSI) to a sufficiently low strength. This paper deals with an actual full-duplex communication system: the base station (BS) has no space limitation, can be equipped with complex self-interference cancellation hardware, so as to have the capability of full-duplex communication; and the user terminal is limited by its own size and cost, A conventional half-duplex (hd) communication can only be performed. In such a system, an upstream user and a downstream user may be paired for full-duplex communication. There are two types of interference in this communication mode: residual self-interference at the base station and co-channel interference (cci) at the downstream user. This paper first studies how to improve the throughput in a frequency-division full-duplex network. In order to improve network throughput as much as possible, we further introduce opportunistic interference cancellation (OIC) techniques to eliminate co-channel interference. The problem of maximizing network throughput can be modeled as a problem of joint power control, channel assignment, and user pairing. This problem is a NP-hard problem due to the presence of an integer variable. In order to solve this problem, a heuristic algorithm with low computational complexity is proposed. The simulation results show that the algorithm has full-duplex gain, multi-user diversity gain and OIC gain relative to half-duplex network, and the performance of full-duplex communication depends on the strength of residual self-interference. We have studied the problem of maximizing throughput in time-division full-duplex networks. The problem is a non-convex problem, and the optimal solution cannot be obtained. We propose a sub-optimal algorithm based on the concave-convex process (CCCP) to solve the problem. In order to further reduce the computational complexity, a heuristic algorithm that does not require an iteration is proposed. The simulation results show that the time-division full-duplex network using the method has full-duplex gain and multi-user diversity gain similar to the frequency-division full-duplex network, and the performance of full-duplex communication depends on the strength of the residual self-interference. We have studied the power efficiency of full-duplex networks. In the case of incomplete channel state information (CSI), we give the feasible domain of the full-duplex user's transmission power, and the numerical solution of the optimal transmission power is given. In the case of high signal-to-noise ratio, we further derive the closed solution of the optimal transmission power. Based on this closed solution, we propose a comparison criterion for the power efficiency of full-duplex communication and half-duplex communication. Finally, we study the compromise between energy efficiency (EE) and spectral efficiency (SE) in full-duplex networks. Since the self-interference cancellation technique has not been fully mature, we have studied two kinds of residual self-interference model _ fixed residual self-interference model and linear residual self-interference model, respectively. Under these two kinds of residual self-interference, we compare the energy efficiency and spectrum efficiency of full-duplex communication and half-duplex communication, and put forward the necessary conditions for full-duplex communication over half-duplex communication, respectively. For the fixed residual self-interference model, in the case of only one pair of users, we prove that the total transmission power of the user is a strict convex function of the spectral efficiency. Based on this convexity, we continue to demonstrate that energy efficiency is a pseudo-concave function of spectral efficiency. We then continue to extend the energy efficiency and the pseudo-concavity of the spectral efficiency to the scenes of multiple users, and propose an algorithm for finding the global optimal energy efficiency. In order to solve the linear residual self-interference model, the optimal solution can not be obtained because the interference situation is more complex, and a heuristic algorithm is proposed. The algorithm is used to solve the two sub-problems of power control and user pairing. The simulation analysis verifies our theoretical derivation and the effectiveness of the proposed method.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92
，
本文编号：2491399
[Abstract]:With the rapid spread of mobile devices, the increasing demand for data traffic presents a great challenge to the wireless communication system. In order to improve the capacity of the wireless network, simultaneous on-band full-duplex communication technology is proposed, and more and more attention is paid to the academic and industrial circles. A full-duplex (FD) communication technology allows a user to transmit and receive signals simultaneously within the same frequency band, and thus it is possible to double the capacity of the communication link. The biggest challenge for full-duplex communication is the self-interference (SI) generated by the device itself. There are three types of self-interference cancellation technologies: transmission path suppression, analog domain cancellation, and digital domain elimination. The combined use of these three types of self-interference cancellation methods can suppress the residual self-interference (RSI) to a sufficiently low strength. This paper deals with an actual full-duplex communication system: the base station (BS) has no space limitation, can be equipped with complex self-interference cancellation hardware, so as to have the capability of full-duplex communication; and the user terminal is limited by its own size and cost, A conventional half-duplex (hd) communication can only be performed. In such a system, an upstream user and a downstream user may be paired for full-duplex communication. There are two types of interference in this communication mode: residual self-interference at the base station and co-channel interference (cci) at the downstream user. This paper first studies how to improve the throughput in a frequency-division full-duplex network. In order to improve network throughput as much as possible, we further introduce opportunistic interference cancellation (OIC) techniques to eliminate co-channel interference. The problem of maximizing network throughput can be modeled as a problem of joint power control, channel assignment, and user pairing. This problem is a NP-hard problem due to the presence of an integer variable. In order to solve this problem, a heuristic algorithm with low computational complexity is proposed. The simulation results show that the algorithm has full-duplex gain, multi-user diversity gain and OIC gain relative to half-duplex network, and the performance of full-duplex communication depends on the strength of residual self-interference. We have studied the problem of maximizing throughput in time-division full-duplex networks. The problem is a non-convex problem, and the optimal solution cannot be obtained. We propose a sub-optimal algorithm based on the concave-convex process (CCCP) to solve the problem. In order to further reduce the computational complexity, a heuristic algorithm that does not require an iteration is proposed. The simulation results show that the time-division full-duplex network using the method has full-duplex gain and multi-user diversity gain similar to the frequency-division full-duplex network, and the performance of full-duplex communication depends on the strength of the residual self-interference. We have studied the power efficiency of full-duplex networks. In the case of incomplete channel state information (CSI), we give the feasible domain of the full-duplex user's transmission power, and the numerical solution of the optimal transmission power is given. In the case of high signal-to-noise ratio, we further derive the closed solution of the optimal transmission power. Based on this closed solution, we propose a comparison criterion for the power efficiency of full-duplex communication and half-duplex communication. Finally, we study the compromise between energy efficiency (EE) and spectral efficiency (SE) in full-duplex networks. Since the self-interference cancellation technique has not been fully mature, we have studied two kinds of residual self-interference model _ fixed residual self-interference model and linear residual self-interference model, respectively. Under these two kinds of residual self-interference, we compare the energy efficiency and spectrum efficiency of full-duplex communication and half-duplex communication, and put forward the necessary conditions for full-duplex communication over half-duplex communication, respectively. For the fixed residual self-interference model, in the case of only one pair of users, we prove that the total transmission power of the user is a strict convex function of the spectral efficiency. Based on this convexity, we continue to demonstrate that energy efficiency is a pseudo-concave function of spectral efficiency. We then continue to extend the energy efficiency and the pseudo-concavity of the spectral efficiency to the scenes of multiple users, and propose an algorithm for finding the global optimal energy efficiency. In order to solve the linear residual self-interference model, the optimal solution can not be obtained because the interference situation is more complex, and a heuristic algorithm is proposed. The algorithm is used to solve the two sub-problems of power control and user pairing. The simulation analysis verifies our theoretical derivation and the effectiveness of the proposed method.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92
，
本文编号：2491399
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