# Empirical Study on 5G NR Cochannel Coexistence
## 2 Related Work  
The coexistence issue for different technologies is widely studied. The survey in [9] presents inter-technology techniques of spectrum sharing in wireless technologies. The survey describes the inter-technology coexistence (in shared spectrum bands) for technologies with a hierarchical and flat regulatory framework with equal access rights. Furthermore, it briefly presents the inter-technology coexistence for different access rights in the hierarchical regulatory framework and for the integration of technologies in different spectrum bands. The complexity of testing interference and the coexistence of wireless systems in critical infrastructure has been reported in [10]. The report highlights the need for studying test methods and performance metrics that allow designers, manufacturers, and customers of new smart communications systems to understand and predict the ability of a device or system to resist interference and coexist within a particular radio frequency environment. According to the type of the spectrum, whether it is dedicated or shared with other technologies, different coexistence problems might emerge for 5G NR deployments. The coexistence in the unlicensed bands is studied in [11; 12], with results of the coexistence between 5G NR and Wi-Fi in the 6 GHz frequency band available for unlicensed use. Related to the multiple licensed spectrum bands allocated to 5G NR technologies, multiple studies analyzed the coexistence issue with inter- and intra-technologies. Authors in [13] demonstrated on an experimental setup the efficient spectrum sharing for 5G NR, LTE-A Pro and NB-IoT aiming to take advantage of the 700 MHz propagation aspects. Similarly, a field trial study in [14] presents the coexistence between LTE and NR based on a frequency division duplexing (FDD) system under dynamic spectrum sharing (DSS). Furthermore, authors in [15] and [16] study the coexistence between the 5G system and fixed satellite communications in the mid- (3.4 GHz-3.6 GHz) and high-frequency bands (40 GHz), respectively. The results from the coexistence of fixed satellites and 5G in mid-band, based on simulations, and lab and field tests, demonstrated that 5G systems could be deployed on a large scale for commercial deployments. The coexistence aspects for FSS (fixed-satellite services) and FS (fixed services) are discussed in [17]. For the mmWave band, it was demonstrated that 5G IoT systems can meet the interference protection criteria of the FSS from at least several hundred base stations and thousands of IoT terminals simultaneously. Additionally, related simulation-based studies considered the coexistence between different 5G networks in the mid-band spectrum as well. For 5G system operating in the mmW range, mitigation of cochannel interference using multiple beam formations, including directivity of beams and the distance between the base station and terminal device, is proposed in [18] with mathematical analysis and simulations. In [7], cochannel and adjacent channel performance evaluation in the mid-band frequency range of 3.5 GHz between an enhanced mobile broadband (eMBB) macro network and an ultra-reliable low latency communication (URLLC) factory network demonstrated that macro downlink interference results in reduction in uplink and downlink capacity and service availability for certain synchronized and unsynchronized TDD patterns. The conclusion of the study highlights that a local factory can coexist with wide-area network when certain isolation is guaranteed to protect the URLLC traffic in the worst-case scenario. In a similar way in [8], the authors highlight that the coexistence of the public macro network and the non-public network is very difficult, unless the isolation between the networks is sufficiently large. These studies also point out the issue of the cross-link interference between public and non-public UEs. This is highlighted by authors in [19], where cross-link interference mitigation techniques from different authors from the literature are compiled.