The wireless broadcasting system is a type of wireless communication system, typically utilizing broadcast encryption (BE) technology to efficiently manage and control access to a large number of receivers, thereby achieving effective content distribution and privacy protection. Traditional wireless broadcasting systems based on BE generally rely on a centralized architecture, which makes them prone to single points of failure and complicates the implementation of time-based access control for encrypted content. Although existing decentralized broadcast encryption (DBE) technologies can deploy wireless broadcasting systems in decentralized architectures, they still fail to achieve time control over encrypted content. In contrast, while timed-release encryption (TRE) technology enables time control over encrypted content, it remains dependent on a centralized architecture. Integrating these technologies with decentralized functionality, while ensuring efficient key storage and ciphertext distribution, remains a challenge. In this paper, we propose a novel timed and decentralized wireless broadcasting system (TWBS), which allows broadcasters to impose time restrictions on encrypted broadcast content while enabling receivers to independently generate public and private keys. The TWBS is built upon a new cryptographic primitive known as timed-release decentralized broadcast encryption (TRDBE). We instantiate the TRDBE scheme, which supports efficient key storage and ciphertext distribution. Both theoretical and experimental analyses demonstrate that the TRDBE-based TWBS system has excellent availability.