# An Integrated Cognitive Radio Network for Coastal Smart Cities
## 1 Introduction  
A coastal smart city is an up-and-coming architecture that allows for hybrid communications with a view to enable imaginative and innovative services for onboard users. A coastal city involves both terrestrial (vehicular) and maritime communications, thereby serving terrestrial and marine users by providing efficient and reliable paths. With the aim of enabling several vehicular and maritime applications (e.g., road safety and shipment to entertainment-associated information), and to fulfill all the expectations in providing services from each of these applications, here we introduce an integrated cognitive architecture. We citizens are actually exposed to a plethora of mobile applications for vehicular and maritime networks. This increase in the number of smart devices has caused difficulty in maintaining stable networking and in meeting the increasing demands of different users. Centralized cloud computing has been used as a straightforward alternative to implementing complicated services; however, due to latency constraints in different networks, cloud computing is not a good remedy for these issues [1]. Fog computing (FC) is a technology that brings services nearer to the end user, thereby improving end-to-end latency. Because the nature of both vehicles and ships in these networks is extremely dynamic, another issue is establishing a stable route to provide diversified services for different network applications. Software-defined networking (SDN) and network function virtualization (NFV), two emerging notions that are gaining popularity in both academia and industry, have inspired a good way to solve this problem [2]. Moreover, dedicatedspectrums for automobile and maritime communication systems have been found to be insufficient due to an inevitable increase in the number of both vehicular and marine users and the demands of each of these applications [3; 4]. The cognitive radio seems to be a corrective approach to overcome spectrum shortage issues in different networks. Consequently, to maintain stable networking and meet the increasing demands of mobile data traffic, network engineers are required to provide an effective solution to improve users' experiences. This means that citizens need an all-in-one framework to meet their growing needs in a more effective and efficient way. To cope with the inevitable increase in data traffic, integration of SDN and NFV seems to be a viable solution to launching and managing virtual networks (VNs) on demand and at greater speed, respectively. NFV is basically a transition from proprietary hardware-based solutions to multi-vendor open solutions. NFV is like a soft appliance that can be installed on demand, whereas SDN is smart plumbing that can be changed on command. The integration reduces provisioning time from months to minutes, reduces costs, improves service-request response times, reacts faster to changing services (allowing right-sized deployments to customers), and offers competitive services. Due to this integration, the changing needs of virtual network functions (VNFs) are now automatically followed by network configurations, and an authorized person is able to track the owner of a service and the reasons why these certain configurations are required. A VNF is the virtualization of a certain NF that should operate independently. NFVs are actually services that are deployed by NFV. SDN is a critical component in the majority of NFV deployments. NFV offers silo-free services (i.e., a common-layer platform with compute, storage, and network resources) where there is no duplication for each service. The infrastructure supports NFs across many geographic locations. Both NFV and SDN are complementary technologies that simplify network management and that can be applied to different network types. NFV can use SDN as a part of service function chaining (SFC), and SDN can provide connectivity between VNFs [5; 6]. Previously, in order to add new features in the network, network engineers needed to purchase new equipment from different vendors.