# Blockchain-Driven Intelligent Scheme for IoT-Based Public Safety System beyond 5G Networks
## 3 Role of Blockchain in 6G Services
### Spectrum Sharing  
The explosive growth of bandwidth-intensive Internet applications such as live audio and video streaming, web conferencing, big data processing, etc., requires high-speed network access with a higher frequency spectrum. The 6G wireless technology provides high-speed network access with ultra-reliable low-latency communication (URLLC) using a higher-frequency spectrum [42]. However, it also increases congestion and interference in the communication network. To overcome this issue, it is required to share the spectrum properly that enhances communication capacity and spectrum efficiency. Spectrum sharing aims to efficiently use scarce natural resources to ensure fairness between mobile users. There are two types of methods for spectrum sharing: static and dynamic spectrum sharing. Out of these two spectrum-sharing mechanisms, dynamic spectrum sharing is the most adopted method; it provides feasible, flexible, and efficient spectrum management based on cognitive radio technology [43; 44]. The variety of spectrum bands and the rivalry between different mobile network operators are the challenges in the 6G spectrum sharing. After lots of research, many solutions were proposed in [45; 46] for efficient spectrum sharing; however, the solutions that address the spectrum scarcity problem face issues such as single point of failure, malicious activity from unauthorized users, and security concerns.  
To mitigate the aforementioned issue, many researchers incorporate blockchain with 6G technology, which improves security and system performance [47]. For example, [PERSON] et al. [48] integrated AI with blockchain for radio spectrum resource allocation in 6G-based enhanced URLLC service. They focused on resource scheduling, classification,and neural network optimization issues between IoT devices. For that, they proposed a reinforcement learning approach with a blockchain-integrated hybrid cloud. Their presented scheme uses unified coding and identification standards to build a public management platform to register and manage IoT device information. The findings reveal that the adopted scheme effectively increases spectrum utilization with security and reliability. Further, in [49], the authors presented a blockchain-based user-autonomy spectrum-sharing framework that efficiently manages the heterogeneous devices of the IoT network. They designed a swarm intelligence approach and a dynamic tip selection algorithm to enhance the system and global utility. The simulation results revealed that the proposed scheme minimizes the average waiting time of transactions and power consumption. Moreover, it enhances global utility, throughput, and spectral efficiency. Then, [PERSON] et al. [50] presented a blockchain-based security solution for access control and preserving the data privacy of users' resources. Furthermore, they introduced a Q-learning approach with machine-type communication (MTC) that enhanced the performance in the 6G environment. Compared to the existing schemes, their proposed scheme outperformed in terms of the success ratio, access time modification, time complexity, and memory utilization.