The fifth-generation new radio (NR) cellular communication is featured with numerous advancements over Long Term Evolution (LTE) and earlier technologies. It enables more flexible physical-layer resource scheduling across multiple dimensions, and two representative techniques are beamspace transmissions and time-frequency numerology selection. Nevertheless, the lightweight physical-layer secure transmission in NR remains under investigation, especially taking NR beamspace and mobility into consideration. In this work, we propose a physical-layer wireless key generation (KG) efficient beamspace adaptation scheme for NR, where the KG capacity is theoretically characterized by critical NR components including beam direction and beamwidth. In addition, we consider the impacts of user mobility on KG performance. Since NR beamspace plays a key role in deciding the channel probing window in the spatial dimension, the NR beamspace directly affects channel probing results and hence the KG efficiency. To this end, NR beam parameters are obtained to improve the KG performance. Especially, we propose to optimize the NR beamwidth for maximizing the secrecy-delay efficiency, because a tradeoff exists in adapting the beamwidth where smaller beamwidth can improve the channel estimation accuracy but increase the beam sweeping delay. Theoretical analysis and simulation results show that the beam direction adaptation provides spatial degrees of freedom for NR to enhance KG, by enabling beam selection pointing at target areas with richer multipath scatterings. Experimental results demonstrate that the narrow beam is beneficial to enhancing the channel estimation accuracy and the resultant key agreements.
The fifth-generation new radio (NR) cellular communication is featured with numerous advancements over Long Term Evolution (LTE) and earlier technologies. It enables more flexible physical-layer resource scheduling across multiple dimensions, and two representative techniques are beamspace transmissions and time-frequency numerology selection. Nevertheless, the lightweight physical-layer secure transmission in NR remains under investigation, especially taking NR beamspace and mobility into consideration. In this work, we propose a physical-layer wireless key generation (KG) efficient beamspace adaptation scheme for NR, where the KG capacity is theoretically characterized by critical NR components including beam direction and beamwidth. In addition, we consider the impacts of user mobility on KG performance. Since NR beamspace plays a key role in deciding the channel probing window in the spatial dimension, the NR beamspace directly affects channel probing results and hence the KG efficiency. To this end, NR beam parameters are obtained to improve the KG performance. Especially, we propose to optimize the NR beamwidth for maximizing the secrecy-delay efficiency, because a tradeoff exists in adapting the beamwidth where smaller beamwidth can improve the channel estimation accuracy but increase the beam sweeping delay. Theoretical analysis and simulation results show that the beam direction adaptation provides spatial degrees of freedom for NR to enhance KG, by enabling beam selection pointing at target areas with richer multipath scatterings. Experimental results demonstrate that the narrow beam is beneficial to enhancing the channel estimation accuracy and the resultant key agreements.
The fifth-generation new radio (NR) cellular communication introduces numerous advancements over Long Term Evolution and earlier technologies. It enables more flexible resource scheduling across multiple dimensions, with beamspace transmissions and time-frequency numerology selection as representative techniques. However, lightweight physical-layer secure transmission in NR remains under investigation, particularly taking NR beamspace into account. In this study, we propose an efficient beamwidth adaptation scheme for NR physical-layer wireless key generation (KG). Given the pivotal role of NR beamspace in determining the channel probing window in the spatial dimension, it directly influences channel probing results and, consequently, KG efficiency. To address this issue, we study NR beamwidth adaptation for enhancing KG performance. Specifically, we optimize NR beamwidth to maximize secrecy-delay efficiency, revealing the tradeoff involved in adapting beamwidth, where smaller beamwidth improves channel estimation accuracy but increases beam sweeping delay.
The rapid advancement and deployment of 5G NR technology in diverse applications have introduced new challenges to network security. While 5G NR’s architecture allows flexible customization of subcarrier spacing and frame structures, enabling devices to optimize configurations based on mobility, service characteristics, and coverage, research has largely neglected the potential of fine-tuning system parameters to enhance key generation efficiency and security. This paper addresses this gap by analyzing time-frequency domain correlation and key generation rate as key metrics. We explore the impact of parameter selection on the key generation process in 5G NR systems. Using the Pearson correlation coefficient of channel estimates in the time-frequency domain, we propose a parameter selection strategy to improve physical layer security, validated through simulations. Results show that in fast-fading environments, smaller subcarrier spacing yields better results, while in frequency-selective fading channels, larger subcarrier spacing significantly enhances key generation performance.
The wireless channel is inherently an open medium which exposes wireless communication users to the risk of interception. The vulnerabilities of the wireless channel have led to the search for innovative and efficient security solutions at different levels of the network protocol. In particular, the physical layer level allows for implementing some security functions, such as key generation and exchange, by exploiting the intrinsic randomness of the wireless communication channel. In this paper, we analyze the effect of wireless channel and of antenna characteristics on physical layer security (PLS) key generation. The aim is to put in evidence the relation between physical quantities, such as radio channel characteristics or antenna directivity, with higher level secrecy performance indicators, such as the key mismatch between the different communication nodes and the key randomness. For this purpose, we developed a comprehensive numerical model, which implements all the different steps, from signal generation and wireless propagation modeling to key generation through spectral quantization. The reported results show that the multipath richness of the radio channel, as in outdoor urban scenarios, improves the PLS secrecy performances with respect to simpler propagation scenarios. Moreover, we show that the use of more directive antennas in the legitimate communication link improves secrecy. An opposite effect is achieved when the directivity of the eavesdropper antenna is increased, thus improving its ability to perform passive attacks.
As wireless networks evolve toward 5G and 6G, securing communications in dense, dynamic, and potentially adversarial environments becomes increasingly critical. Traditional cryptographic security, relying on symmetric or asymmetric key exchanges at higher layers or pre-provisioning, imposes significant operational complexity—especially in decentralized private networks and tactical deployments where infrastructure is limited and exposure to interception or cryptanalysis is high.This work introduces an environment-aware cryptographic key derivation method that utilizes 5G NR waveforms and Integrated Sensing and Communication (ISAC) principles, accompanied by updates to the security frameworks in 5G and next-generation 6G networks. It exploits radio channel reciprocity to extract highly correlated features observable only by legitimate transceivers, while inherently excluding spatially separated eavesdroppers.Our system derives shared secret keys directly from Channel State Information (CSI), achieving high-entropy keys with a 100% agreement rate and a high key generation rate between legitimate nodes. We demonstrate its robustness using software-defined radios operating in the 5G FR1 band, across diverse environments, while constraining the amount of publicly accessible information available to potential eavesdroppers.By embedding geographical awareness, this approach provides a physically secure key generation method, making it well-suited for 5G/6G systems, private networks, and ultra-massive Machine-Type Communication (umMTC) scenarios. The results highlight the potential of physical layer security for future wireless encryption frameworks with design considerations to maximize security and limit eavesdropping feasibility.
The fifth-generation mobile communication technology (5G) supports wireless data transmission across civil, commercial, industrial, and even military networks, where vast amounts of privacy data are constantly transmitted. However, the open nature of the air interface in 5G systems makes them vulnerable to various attacks. Physical-layer key generation (PKG) has been recognized as a highly promising technology for ensuring data security in 5G systems, while existing PKG schemes achieve low key entropy (i.e., low key randomness) due to poor channel probing and quantization. In this paper, we propose a PKG scheme with high key entropy, tailored to the unique characteristics of 5G systems. First, we design a channel probing method based on the demodulation reference signal in accordance with 5G standards, enhancing the similarity between channel measurements. Next, we introduce a quantization method based on local increment and monotonicity, which effectively leverages channel characteristics to achieve high-speed key generation and improve key entropy. Finally, we use both MATLAB simulation and real-world channel measurements to achieve comprehensive verification of the proposed scheme. The simulation results showed that the proposed scheme increases the key entropy by at least 25% with nearly the same key generation rate compared with existing PKG schemes for 5G systems. The experiment using real-world channel measurements also confirmed that the proposed scheme has higher key entropy.
High level of security is essential in wireless 5G communications. The last few years there has been an increase in research interest in the potential of the radio channel’s physical properties to provide communications security. These research efforts investigate fading, interference, and path diversity to develop security techniques for implementation in 5G New Radio (NR). In this paper, we propose a collaborative scheme to existing physical layer security schemes, taking advantage of the characteristics of the OFDM technique. An OFDM symbol includes the pilot subcarriers, typically essential for the pilot channel estimation process performed at the legitimate receiver. In this work we propose the positions of the subcarriers to change on every OFDM symbol following a probability distribution known only to the legitimate transmitter and legitimate receiver. An eavesdropper, does not have access to the information of the pilot subcarriers positions so, it performs blind channel estimation. The theoretical analysis is based on the information theoretic problem formulation and is confirmed by simulations. The performance metrics used are the secrecy capacity and the outage probability. The proposed scheme is very simple and robust, strengthening security in multimedia applications.