This paper considers the support of time-constraint services to mobile users in a ubiquitous environment. The challenge for a database with time constraint services becomes more important in a ubiquitous computing environment. Low bandwidth, unreliable wireless links, and frequent disconnections of ubiquitous environments make it difficult to satisfy the timing requirements of supported strategies. This study investigates broadcast scheduling strategies for push-based broadcast with timing constraints in the form of deadlines, and proposes a multichannel scheduling algorithm for push-based broadcast with timing constraints. Under such a scheme, modifying the access method in the broadcast period supports data allocation on multiple channels, allowing time-constraint property to be satisfied in ubiquitous environments. The proposed dissemination policy and adaptive bandwidth allocation scheme obtain sufficient conditions such that all the time- bounded traffic sources satisfy their timing constraints to provide various quality-of-service (QoS) guarantees in the broadcast period. Our goal is to identify scheduling algorithms for broadcast systems that ensure requests meet their deadlines. This study examines the performance of traditional real-time strategies and mobile broadcasting strategies, and demonstrates that traditional real-time algorithms do not always perform the best in a mobile environment. The proposed design indeed achieves good performance in ubiquitous environments.
網際網路技術學刊=Journal of Internet Technology 11(6)，頁777-786