# Blockchain for Future Wireless Networks: A Decade Survey
## 2 Background
### Blockchain Technology
#### 2.3.2 Integration of Blockchain and WNs  
Undoubtedly, the next generation WN has a blend of modern technologies that use virtualization and cloudification to handle an enormous amount of data generated by the WN users. Furthermore, the popularization of cellular networks, which use WN as their core component in driving cellular services, has seen a significant growth in data traffic. These voluminous data are unable to be handled by a single technology, and hence, the researchers have started to integrate multiple technologies, such as AI, IoT, automation, and many more, in WN to handle the WN services seamlessly. Since the inception of WN, the data have been the foremost important entity that served millions of users by connecting them around the world, offering on-demand services, entertaining with multimedia services, and many more. However, it has been observed that many a time, the en-route data of WN are manipulated by the attackers, increasing the unexpected behavior of the system. Therefore, there is a need for a concrete technology that has secure storage capabilities, where attackers cannot tamper with the data. Blockchain is one such promising technology with cryptographic techniques and a distributed ledger that is shared among the authenticated members of the blockchain that ensures safety and privacy for WNs [10]. Additionally, it facilitates a smart contract, a digitally secure signed program to establish a contract between two entities without the need for a third party for transaction settlement. Multiple researchers are working on integrating blockchain technology with the WNs. For instance, [PERSON] et al. [55] proposed a resource allocation scheme using blockchain underlying a 6G network. Due to the scarcity of spectrum in a 6G network, it is infeasible to efficiently allocate resources to different 6G WN users. Therefore, for efficient sharing and managing the resources, blockchain technology has been proposed that improves the performance of the 6G network, reduces administrative cost, and maximizes spectrum efficiency. Then, [PERSON] et al. [56] integrated blockchain with 6G network using a smart contract. They used consensus protocol with a 6G interface that benefits service level agreement, trusted database, and fair access. Further, [PERSON] et al. [57] analyzed the application of blockchain on the internet of vehicles (IoVs). In that, blockchain offers a decentralized and secure environment that resolves the issue of centralized problems and improves IoVs architecture. Figure 6: Hierarchy of blockchain. From the perspective of security, researchers across the globe found different methods to overcome the security and privacy issues of WNs. For example, [PERSON] et al. [32] analyzed security vulnerabilities and threats in wireless communications. They discussed various security attacks, protocols, and algorithms in WNs and studied efficient defense mechanisms for security improvements. They focused on physical-layer security and introduced a family of jamming attacks with their countermeasures. [PERSON] et al. [58] discussed security issues, such as confidentiality, integrity and availability in IoT. They studied blockchain-based architecture for IoT applications, such as smart homes, smart grids, and Industry 4.0. Then, [PERSON] et al. [59] discussed existing authentication and privacy-preserving schemes for 4G and 5G networks along with taxonomy. They discovered research gaps in existing security mechanisms, such as attacks against authentication schemes, availability, and integrity. The paper presents a comparative analysis of existing security mechanisms and their countermeasures that resolve security and privacy issues in WNs. With the upcoming standards and technologies of WN, the WN use cases are becoming more competent and intelligent, such as smart supply chain, smart healthcare, smart vehicles, and smart cities. However, incorporating intelligence in such applications can sometimes lure the attackers into targeting them.