## 2 Theoretical Background and Literature Review
### Blockchain and Smart Contracts  
#### 2.2.1 Blockchain Technology: The Theoretical Foundation  
Blockchain technology, first brought into the public eye under the pseudonym [PERSON] [45] with the introduction of Bitcoin, has rapidly evolved to become a key pillar in modern digital infrastructure. At its core, blockchain technology is highly regarded for its capacity to create an unchangeable record of transactions within a decentralized system. This feature is central to its acclaim in the digital world, as it provides strong security and reliability, making blockchain a pivotal technology in the era of digital transformation [46; 47; 48]. Figure 1: An integrated 5G ceramic chip antenna array featuring a combination of low-band and high-band units, tailored for 24.25 GHz to 29.5 GHz and 37 GHz to 40 GHz frequency ranges, respectively, arranged in a 1 \(\times\) 5 configuration to form a comprehensive 5G ceramic antenna system module. The essence of blockchain lies in its decentralized nature, which is a significant departure from traditional centralized systems. In a blockchain network, every participant has access to and can verify the transactions in the public ledger. This transparency is a paradigm shift, enabling direct transactions between parties without the need for intermediaries, thereby enhancing both the transparency and integrity of the transactions. The unique structure of blockchain, where transactions are recorded in blocks and linked cryptographically to previous blocks, forms a chain that is virtually impossible to alter. This immutability is one of blockchain's most defining characteristics. Moreover, the integration of distributed computing across the network nodes ensures that transaction verification and storage are secure and tamper-proof. This technology has found its applications spanning various sectors, from finance, where it revolutionizes payments and trading, to manufacturing, where it streamlines supply chains, and even to realms like smart cities and healthcare. Blockchain's versatility and security have made it a technology that holds diverse meanings and enormous potential for the future, promising to play an increasingly vital role across multiple domains [49; 50; 51; 52; 53; 54; 55]. Blockchain technology, applied across diverse sectors, enhances the integrity and efficiency of various processes, from financial transactions to supply chain management. Its decentralized nature, pivotal in manufacturing, ensures product quality and cost-effectiveness. When combined with 5G technology, blockchain's potential multiplies, offering rapid, secure data transmission and processing, critical in areas like finance and healthcare. This synergy particularly benefits IoT applications in smart cities and healthcare, where secure data management is crucial. The fusion of blockchain's reliability and 5G's speed not only improves existing services but also paves the way for innovative applications, such as the swift execution of smart contracts [66; 67; 68; 69]. [PERSON] and [PERSON] [70] explore the integration of IoT, Edge Intelligence, 5G, and blockchain in autonomous vehicles, reviewing their impact on AV architecture. [PERSON] and colleagues [69] discuss blockchain's potential to enhance dynamic spectrum access and network slicing for 5G and beyond, emphasizing its role in secure, efficient, and transparent network slicing. [PERSON] et al. [71] develop a blockchain-based secure data collection and exchange scheme for the Internet of Vehicles in a 5G environment, focusing on enhancing communication security using Elliptic Curve Cryptography. They aim to address potential attacks in IoV environments with a detailed security analysis. [PERSON] and others [72] highlight the use of blockchain and 5G to boost the security, reliability, and privacy of IoT-based public safety applications, focusing on the architecture's performance and the challenges of implementing blockchain in 5G networks. [PERSON] et al.