Secure Relay Networks in Text Semantic Communication

With the rapid development of 6G networks and intelligent applications, traditional bit-level communication paradigms face challenges in balancing efficiency, reliability, and security. Semantic communication, which transmits information meaning rather than raw data, offers new solutions for redundancy reduction and resource utilization. However, security threats like eavesdropping and data tampering persist in relay networks, requiring innovative approaches under semantic communication frameworks. This paper proposes a novel Semantic Relay (SemRelay)-assisted secure transmission framework. First, we establish a two-phase transmission model: the semantic relay decodes and forwards text information from the base station (BS) to resource-constrained users, while eavesdroppers (EVE) attempt interception using traditional bit-level decoders. By introducing the semantic similarity as a key performance metric and deriving secrecy outage probability, we bridge semantic fidelity with physical layer security. Our analysis combines semantic communication with physical layer security in relay networks, evaluating semantic relay’s security performance under various channel conditions through derived secrecy outage probability (SOP) expressions.