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One of the defining characteristics of 5G is the flexibility it offers for supporting different services and communication scenarios. For this purpose, usage of multiple numerologies has been proposed by the 3rd Generation Partnership Project (3GPP). The flexibility provided by multi-numerology system comes at the cost of additional interference, known as inter-numerology interference (INI). This paper comprehensively explains the primary cause of INI, and then identifies and describes the factors affecting the amount of INI experienced by each numerology in the system. These factors include subcarrier spacing, number of used subcarriers, power offset, windowing operations and guard bands.Index Terms-5G New Radio, inter-numerology interference, multi-numerology systems.

The diverse requirements of next-generation communication systems necessitate awareness, flexibility, and intelligence as essential building blocks of future wireless networks. The awareness can be obtained from the radio signals in the environment using wireless sensing and radio environment mapping (REM) methods. This is, however, accompanied by threats such as eavesdropping, manipulation, and disruption posed by malicious attackers. To this end, this work analyzes the wireless sensing and radio environment awareness mechanisms, highlighting their vulnerabilities and provides solutions for mitigating them. As an example, the different threats to REM and its consequences in a vehicular communication scenario are described. Furthermore, the use of REM for securing communications is discussed and future directions regarding sensing/REM security are highlighted.INDEX TERMS 5G, 6G, cryptography, joint radar and communication (JRC), physical layer security, radio environment mapping (REM), REM security, sensing security, vehicle-to-everything (V2X) communication, wireless sensing, WLAN sensing.As explained earlier, our surroundings contain a myriad of radio signals. These signals can be leveraged to extract information about the environment itself and the users/devices within. As such, a malicious node might have the following motivations when attacking a (communication and/or sensing) wireless network:• Confidentiality Violation: The malicious node tries to intercept either the communication or characteristics of the legitimate nodes. In the context of sensing, this information may include a user's location, mobility pattern, social trends, etc. • Degradation: The malicious node attempts to impair the communication link and/or sensing capabilities of the legitimate parties. • Exploitation: The malicious node tries to exploit the communication and/or sensing for its own benefit. This may include learning and then manipulating the legitimate communication (or sensing) to acquire resources for itself.Corresponding to the aforementioned intentions of the malicious attackers, the network strives to guarantee that its nodes and users are protected. This includes ensuring no illegitimate access to the information/transmission is allowed, the data shared between legitimate nodes is accurate, and there is no disruption of the services offered by the network [16]. B. SECURITY THREATS -COMMUNICATION VS SENSINGThe broadcast nature of wireless communication (or signals in general) renders it susceptible to various security threats. Given below is an overview of how these threats compare for communication and sensing aspects.

The characteristic feature of 5G and beyond networks is the diversity of services, which is required to support different user needs. However, the requirements for these services are often competing in nature, which impresses the necessity of a coordinated and flexible network architecture. Although coordinated multipoint (CoMP) systems were primarily proposed to improve the cell edge performance in 4G, their collaborative nature can be leveraged to support the diverse requirements and enabling technologies of 5G and beyond networks. To this end, we propose the generalization of CoMP to a proactive and efficient resource management framework capable of supporting different user requirements such as reliability, latency, throughput, and security while considering network constraints. This article elaborates on the multiple aspects, inputs, and outputs of the generalized CoMP (GCoMP) framework. Apart from user requirements, the GCoMP decision mechanism also considers the CoMP scenario and network architecture to decide upon outputs such as CoMP scheme or appropriate coordinating clusters. To enable easier understanding of the concept, a case study illustrating the effect of different combinations of GCoMP framework's outputs on varying user requirements is presented.INDEX TERMS 5G, 6G, backhaul, clustering, coordinated multipoint (CoMP), energy efficiency, flexibility, generalized CoMP (GCoMP), multi-TRP MIMO, quality of service (QoS), radio resource management (RRM).

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Fifth generation (5G) radio access technology (RAT) is expected to flexibly serve multiple services with extremely diverse requirements. One of the steps taken toward fulfilling this vision of the 5G-RAT is an introduction of the multinumerology concept, where multiple frame structures with different subcarrier spacings coexist in one frequency band. Though efficient in providing the required flexibility, this approach introduces a new kind of interference into the system known as inter numerology interference (INI). This study is geared toward analyzing the INI problem considering a cyclic prefix orthogonal frequency domain multiplexing (CP-OFDM) system and exposing the factors contributing to it through mathematical analyses. In-depth discussion of various critical issues concerning multi-numerology system such as frequency domain multiplexing and time domain symbol alignment for mixed numerologies is presented. Based on the findings of the conducted analyses, the paper highlights some approaches for minimizing INI in the system. The developed mathematical analysis is finally verified by Monte-Carlo simulations.

Enabling technologies of 5G and beyond wireless communication networks, such as millimeter-wave communication, beamforming, and multiple-input multiple-output (MIMO) antenna systems, are becoming increasingly dependent on accurate information of the physical environment for optimized communication performance. The acquisition of this information is a significant challenge, which can be eased by knowledge of the radio environment. Radio environment mapping (REM) has long been considered an enabler of cognitive radios (CRs). However, the limitations of radios effectively confined the application of REM to spectrum sensing and interference mapping. With the advent of more capable software-defined radios and advanced networks, the idea of a truly intelligent communication system empowered by enhanced REM can be realized. To this effect, we propose the generalized radio environment monitoring (G-REM) concept to include all aspects of the radio environment. We outline a general, self contained framework which enables radio environment monitoring in standalone devices. The presented G-REM framework comprises of different information sources, sensing methods, sensing modes, and mapping techniques to enable the realization of more reliable, secure, efficient, and faster future wireless networks. The accompanying challenges and future research direction are also provided.