Blockchain in Communication Networks: A Comprehensive Review

ABSTRACT Blockchain is emerging as a trust substrate for multi‐operator communication networks where centralised control can hinder auditability, settlement, and cross‐domain security. This survey consolidates blockchain fundamentals relevant to telecom (consensus, cryptography, smart contracts, and governance) and synthesises how these primitives enable secure logs, automated roaming/settlement, decentralised identity, resource trading, and 5G/6G slicing and edge computing. The authors introduce an end‐to‐end taxonomy that maps blockchain mechanisms to network functions and cross‐cutting constraints and provide comparative evidence from representative studies on performance (latency/throughput), operational cost, and deployment maturity. A structured literature search and screening process over major digital libraries yields a curated corpus spanning 2015–2025, with emphasis on recent advances in permissioned and hybrid designs suited to low‐latency networking. The review identifies persistent gaps – scalability under high churn, energy and hardware overhead, interoperability across chains and legacy control planes, and regulatory compliance – and distils actionable research directions, including AI‐assisted consensus, cross‐chain orchestration for multi‐domain slicing, and privacy‐preserving accountability. Finally, case studies illustrate practical design trade‐offs and highlight when blockchain provides a net benefit over conventional databases.