A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> This article discusses opportunities and challenges of physical layer security integration in MaMIMO systems. Specifically, we first show that MaMIMO itself is robust against passive eavesdropping attacks. We then review a pilot contamination scheme that actively attacks the channel estimation process. This pilot contamination attack not only dramatically reduces the achievable secrecy capacity but is also difficult to detect. We proceed by reviewing some methods from literature that detect active attacks on MaMIMO. The last part of the article surveys the open research problems that we believe are the most important to address in the future and give a few promising directions of research to solve them. <s> BIB001 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> The heterogeneous cellular network is believed to be a promising deployment of cellular networks in 5G. This chapter comprehensively studies physical layer security in a multitier HCN where BSs, authorized users and eavesdroppers are all randomly located. We first propose a truncated average received signal power-based secrecy mobile association policy. Under this policy, we investigate and provide tractable expressions for the connection probability and secrecy probability of a randomly located user. We further evaluate the network-wide secrecy throughput and the minimum secrecy throughput per user under both connection and secrecy probability constraints. We prove that the proposed mobile association policy significantly enhances the secrecy throughput performance of the HCN. <s> BIB002 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> In this paper, multi-hop cooperative techniques are adopted to improve the physical-layer security in 5G large-scale decode-and-forward relay networks with massive relays and eavesdroppers. The utilization of graph theory is investigated to relieve the burden of massive nodes and ease the cooperative anti-eavesdropping transmission designs. In particular, a secrecy weighted graph is first established according to the network topology. Three scenarios associated with different levels of wiretapping capability are taken into account. Accordingly, secrecy measurements are converted into the weight of each edge and three efficient cooperative anti-eavesdropping strategies are then proposed for physical-layer security enhancement based on the shortest path algorithm, respectively. It is verified that the proposed cooperative anti-eavesdropping strategies have the property of low complexity and are more attractive for large-scale networks. Simulation results highlight the efficiency and effectiveness of our designs. It has been shown that two-hop transmission does not always promise performance gain in terms of secrecy gain. On the contrary, the proposed strategies are able to provide considerable improvement for different cases, emphasizing the necessity of adopting multi-hop cooperative anti-eavesdropping techniques to improve the physical-layer security. <s> BIB003 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> After 4G network becomes a global commercial success, the researchers are now looking at the future 5G technologies, both in standardization bodies and in research projects. Researchers find that the security architecture used in 4G can not satisfy the needs of 5G. Some researchers proposed a kind of unified network security architecture which we find it inflexible. In this paper, we will propose a more flexible hierarchical security architecture which can be adjusted to the needs of the application scenarios of 5G-eMBB, mMTC and URLLC. Under this architecture, we will introduce a cross-layer light weight authentication scheme and a novel physical layer security assisted encryption scheme which is based on both the key streams and the channel information in f-OFDM system. <s> BIB004 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> Physical layer security which safeguards data confidentiality based on the information-theoretic approaches has received significant research interest recently. The key idea behind physical layer security is to utilize the intrinsic randomness of the transmission channel to guarantee the security in physical layer. The evolution towards 5G wireless communications poses new challenges for physical layer security research. This paper provides a latest survey of the physical layer security research on various promising 5G technologies, including physical layer security coding, massive multiple-input multiple-output, millimeter wave communications, heterogeneous networks, non-orthogonal multiple access, full duplex technology, etc. Technical challenges which remain unresolved at the time of writing are summarized and the future trends of physical layer security in 5G and beyond are discussed. <s> BIB005 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> In this correspondence, we investigate the physical layer security for cooperative nonorthogonal multiple access (NOMA) systems, where both amplify-and-forward (AF) and decode-and-forward (DF) protocols are considered. More specifically, some analytical expressions are derived for secrecy outage probability (SOP) and strictly positive secrecy capacity. Results show that AF and DF almost achieve the same secrecy performance. Moreover, asymptotic results demonstrate that the SOP tends to a constant at high signal-to-noise ratio. Finally, our results show that the secrecy performance of considered NOMA systems is independent of the channel conditions between the relay and the poor user. <s> BIB006 </s> A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks <s> Secure Physical Layer formations in 5G: <s> In this paper, we design robust beamforming to guarantee the physical layer security for a multiuser beam division multiple access (BDMA) massive multiple-input multiple-output (MIMO) system, when the channel estimation errors are taken into consideration. With the aid of artificial noise (AN), the proposed design are formulated as minimizing the transmit power of the base station (BS), while providing legal users and the eavesdropper (Eve) with different signal-to-interference-plus-noise ratio (SINR). It is strictly proved that, under BDMA massive MIMO scheme, the initial non-convex optimization can be equivalently converted to a convex semi-definite programming (SDP) problem and the optimal rank-one beamforming solutions can be guaranteed. In stead of directly resorting to the convex tool, we make one step further by deriving the optimal beamforming direction and the optimal beamforming power allocation in closed-form, which greatly reduces the computational complexity and makes the proposed design practical for real world applications. Simulation results are then provided to verify the efficiency of the proposed algorithm. <s> BIB007
The physical layer security gains a hike in the 5G network communications. The conventional cryptographic solutions for security impose the difficulties in the distribution and management of secret keys. But the physical layer has provided reliable and flexible security levels through various protocols. The concept of the physical layer is to "utilize the intrinsic randomness of the transmission channel to guarantee the security in physical layer" BIB005 . The existing approaches to security require strong constraints and high additional costs for the users of public networks. Therefore the new concept on physical layer security focuses on the secrecy capacity of the propagation channel, which is adopted by the 5G networks. Gomez et al.  analyzed the physical layer security for uplink NOMA in 5G large area networks. The key mechanism of coverage probability and the effective secrecy throughput is used in their solution. The Signal-toInterference plus Noise Ratio (SINR) is measured with the legitimate user and attackers. Furthermore, Forouzesh et al. BIB001 analyzed the physical layer security for Power Domain (PD)-NOMA in HetNet. The novel concept of resource allocation scheme is presented to maximize the sum secrecy rate in PD-NOMA based HetNet. The interference in the signals is considered as an eavesdropper in their approach. An alternative search method algorithm is adopted for the optimization problem. Furthermore, Liu et al. BIB003 discussed the physical layer security for 5G-NOMA on the basis of stochastic geometry approaches and the location of the user. Asymptotic secrecy outage probability is used for the multiple-antenna and the simulation result is verified with the Monte Carlo mechanisms. Massive-MIMO has the capability to handle 100+ antenna elements and a large number of independent transceiver chains. The increasing adaptability of Massive-MIMO opens the feasibility of adaption to physical layer security against the eavesdroppers. Kapetanovic et al. BIB002 presented the opportunities and the challenges of physical layer security for Massive-MIMO. The authors presented various possible attack methods and detection of the active attacks on the Massive-MIMO. Wang et al.  discussed the physical layer security in cellular HetNet. The authors proposed a threshold-based secrecy mobile association policy and calculated secrecy and connection probabilities of the random users. The closed-form expressions are used with the secrecy and connection probabilities. Zhang et al. BIB006 presented the cooperative anti-eavesdropping techniques on the basis of graph theory. In their approach, on the basis of network topology, a secrecy weighted graph is calculated. The proposed techniques facilitate the low complex security on the large-scale networks. Chen et al. BIB004 analyzed the physical layer security for cooperative NOMA systems. Pan et al. BIB007 presented hierarchal physical layer security architecture for the 5G Networks based on the cross-layer lightweight authentication scheme and a physical layer security assisted encryption scheme. These schemes are based on the key streams and the channel information. An overview of the state-of-the-art solutions for the physical layer securitytechnologies in the 5G secure communications is presented in Table 5 . 