On the Application of Blockchains to Spectrum Management

Abstract

Spectrum sharing mechanisms have evolved since the early 2000s to meet different needs related to increasing spectrum use efficiency, through mechanisms such as database-driven Spectrum Access Systems (SAS) as well as License Shared Access (LSA). Satisfying continued growth in demand for wireless communications will require further advances in spectrum sharing. This paper considers the application of blockchain technology to this challenge.

The emergence of the cryptocurrency Bitcoin has stimulated efforts to apply its underlying technologies to contexts beyond digital payments. Radio spectrum management represents a promising use case. While blockchains could underlie spectrum management more broadly, we focus on dynamic spectrum sharing applications. Like the cooperative approaches currently in use, blockchain is a database technology. Unlike the SAS and LSA approaches, a blockchain is a decentralized database in which the owner of the data maintains control, even when information is shared across organizational boundaries.

Blockchains could be used to enhance the effectiveness of various forms of spectrum sharing interactions. Information about access rights and usage can be recorded on a distributed ledger and managed using smart contracts. Blockchain could provide a trusted and secure platform for many spectrum management operations in spectrum sharing scenarios. Compared to traditional databases, potential benefits of blockchain-based systems include:

• Decentralization (no trusted intermediary needed to validate transactions)
• Transparency (transaction information available for entities to review)
• Immutability (information once recorded is difficult to tamper with)
• Availability (replication of data across many independent network nodes)
• Security (all transactions digitally signed and the ledger itself secured through a combination of cryptography and economic incentives)

There are, however, tradeoffs involved in blockchain’s decentralized architecture. For example, blockchains typically do not offer the same performance as traditional databases, especially compared to highly-optimized transaction processing systems. The technology in general is immature. And there are a variety of different ways blockchain can be implemented, such as public (open to all) vs. permissioned (only authorized parties can access the network), which have implications for performance, security, and governance.

We consider the benefits and limitations of blockchain technology for four forms of spectrum sharing: unlicensed (primary non-cooperative), secondary markets (primary cooperative), opportunistic (secondary non-cooperative), and cooperative sharing (secondary cooperative). We find that blockchain-based systems could provide a range of benefits including: Increased speed in the evaluation of available spectrum resources; facilitating sophisticated dynamic and rule-based spectrum trading transactions through self-executing smart contracts; generation of auditable, unified transaction records; and helping regulators to evaluate spectrum access efficiency. Under each scenario, we map out where blockchain could provide the greatest value, and how it could be implemented most effectively.

Keywords: spectrum, blockchain, wireless, distributed ledger technology, spectrum sharing