Robust Physical Layer Security for Power Domain Non-Orthogonal Multiple Access-Based HetNets and HUDNs: SIC Avoidance at Eavesdroppers
Robust Physical Layer Security for Power Domain Non-Orthogonal Multiple Access-Based HetNets and HUDNs: SIC Avoidance at Eavesdroppers
复制标题
DOI：
10.1109/access.2019.2932805
复制
发表时间：
2018-06
期刊：
影响因子：
3.9
通讯作者：
Moslem Forouzesh;P. Azmi;N. Mokari;Kai‐Kit Wong;H. Pishro-Nik
中科院分区：
文献类型：
--
作者：
Moslem Forouzesh;P. Azmi;N. Mokari;Kai‐Kit Wong;H. Pishro-Nik
在本文中，我们研究了基于电源域非正交多址（PD-NOMA）的异构蜂窝网络（HetNet）的下行链路物理层安全性。在本文中，我们假设有两类用户：1）可信用户和2）不可信用户（窃听者），其中用户的透明度对于BS来说不明确，即他们是潜在的窃听者。我们的目标是最大化网络的总保密率。为此，我们制定联合子载波和功率分配优化问题以提高和保密率。此外，我们提出了一种新颖的方案，可以防止窃听者进行连续干扰消除（SIC），而合法用户却可以做到这一点。在实际系统中，所有窃听者的信道状态信息（CSI）在合法发射机上完全可用是不切实际的。此外，由于信道估计的误差，合法用户的CSI也可能是不完美的。因此，我们研究CSI可用性的两种情况：1）节点（合法用户和窃听者）的完美CSI在BS处可用，2）节点的不完美CSI在BS处可用。由于所提出的优化问题是非凸的，我们采用了著名的迭代算法，称为替代搜索方法（ASM）。该算法将优化问题转化为功率分配和子载波分配两个子问题。我们通过逐次凸逼近方法解决功率分配问题，并通过利用网格自适应直接搜索算法（MADS）解决子载波分配子问题。此外，为了研究所提出的解决方法的最优性差距，我们应用了单调优化方法。此外，我们评估了所提出的异构超密集网络（HUDN）中安全大规模连接的方案。此外，我们在本文献中研究了多天线基站场景。最后，我们对所提出的方案与窃听者能够应用 SIC 的传统情况进行了数值比较。数值结果表明，与传统情况相比，所提出的方案显着提高了总保密率。
In this paper, we investigate the physical layer security in downlink of Power Domain Non-Orthogonal Multiple Access (PD-NOMA)-based heterogeneous cellular network (HetNet). In this paper, we assume two categories of users are available: 1) Trusted users and 2) untrusted users (eavesdroppers) at which transparency of users is not clear for the BSs, i.e., they are potential eavesdroppers. Our aim is to maximize the sum secrecy rate of the network. To this end, we formulate joint subcarrier and power allocation optimization problems to increase sum secrecy rate. Moreover, we propose a novel scheme at which the eavesdroppers are prevented from doing Successive Interference Cancellation (SIC), while legitimate users are able to do it. In practical systems, perfectly availability of all eavesdroppers’ Channel State Information (CSI) at legitimate transmitters are impractical. Also CSIs of legitimate users may be also imperfect due to the error of channel estimation. Hence, we study two cases of CSI availability: 1) Perfect CSI of nodes (legitimate users and eavesdroppers) are available at the BSs and 2) imperfect CSI of nodes are available at the BSs. Since the proposed optimization problems are non-convex, we adopt the well-known iterative algorithm called Alternative Search Method (ASM). In this algorithm, the optimization problems are converted to two subproblems, power allocation and subcarrier allocation. We solve the power allocation problem by the Successive Convex Approximation approach and solve the subcarrier allocation subproblem, by exploiting the Mesh Adaptive Direct Search algorithm (MADS). Moreover, in order to study the optimality gap of the proposed solution method, we apply the monotonic optimization method. Moreover, we evaluate the proposed scheme for secure massive connectivity in Heterogeneous Ultra Dense Networks (HUDNs). Furthermore, we investigate multiple antennas base stations scenario in this literature. Finally, we numerically compare the proposed scheme with the conventional case at which the eavesdroppers are able to apply SIC. Numerical results highlight that the proposed scheme significantly improves the sum secrecy rate compared with the conventional case.