Although radio access networks and military radars are different radio services, it has been difficult to coexist between them. The frequency allocations for military radars are relatively limited while radio access networks require a large portion of spectrum. Both systems need to work together to avoid interference. Both systems can coexist, but there are uncertainties. To determine whether coexistence solutions can be found, documentary research was carried out.
Three main components were required for the research process. The first was to examine the current situation regarding military radars and radio access network. Second, they interviewed experts in order to determine the feasibility of coexistence. Third, they looked at the technologies that could allow for coexistence of radio access networks and military radars.
Because they are not transparent in their operation, coexistence can be a problem for military radars. They use frequency hopping to avoid interference and detection. They may also have to utilize state-of–the-art filtering technologies. Additionally, equipment may have to only be sent when needed. They may also need to share data with a shared database.
Experts stressed the importance of inter-industry collaboration and the need to have greater involvement from policy and the economy. The experts also suggested the implementation of agreements that involve the use of shared data bases and the use of radar imaging results to improve the accuracy of individual radar imaging. Experts also suggested the US CBRS, which operates in the 3.55-3.7GHz band, as an example of coexistence among radio access networks and radars.
The experts ranked the most feasible coexistence methods on a scale from 0 to 10. The resources allocation coexistence, coexistence based on location, and coexistence based on cognitive radio were the best-ranked coexistence options. The researchers found that the methods could be divided into uncoordinated or coordinated depending on how the information was exchanged among them.
Researchers also investigated the preconditions of frequency coexistence among military radars and radio access networks. They discovered that the primary prerequisite is the secondary users' ability detect and avoid the presence primary users. Secondary WAS, including RLAN users, must change to another channel within ten seconds of radar activity detection. Users must also perform regular channel availability checks.
These studies have shown that radio access and military radars could coexist. Although it is still early in development, the methods used may not be enough to protect them from interference. Therefore, more research is needed to find effective methods for spectrum sharing.
Researchers concluded that coexistence between military radioaccess networks (radioaccess networks) is possible through resource allocation coexistence, location-based methods, cognitive radio coexistence and other methods. There were some safety issues.