tailieunhanh - Báo cáo hóa học: " Joint Cross-Layer Design for Wireless QoS Content Delivery"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Joint Cross-Layer Design for Wireless QoS Content Delivery | EURASIP Journal on Applied Signal Processing 2005 2 167-182 2005 Hindawi Publishing Corporation Joint Cross-Layer Design for Wireless QoS Content Delivery Jie Chen Division of Engineering Brown University Providence RI02912 USA Email jie_chen@ Tiejun Lv School of Information Engineering Beijing University of Posts and Communications Beijing 100876 China Email lvtiejun@ Haitao Zheng Microsoft Research Asia Sigma Center Beijing 49 Zhichun Road Beijing 100080 China Email htzheng@ Received 14 August 2003 Revised 27 June 2004 We propose a joint cross-layer design for wireless quality-of-service QoS content delivery. Central to our proposed cross-layer design is the concept of adaptation. Adaptation represents the ability to adjust protocol stacks and applications to respond to channel variations. We focus our cross-layer design especially on the application media access control MAC and physical layers. The network is designed based on our proposed fast frequency-hopping orthogonal frequency division multiplex OFDM technique. We also propose a QoS-awareness scheduler and a power adaptation transmission scheme operating at both the base station and mobile sides. The proposed MAC scheduler coordinates the transmissions of an IP base station and mobile nodes. The scheduler also selects appropriate transmission formats and packet priorities for individual users based on current channel conditions and the users QoS requirements. The test results show that our cross-layer design provides an excellent framework for wireless QoS content delivery. Keywords and phrases cross-layer design wireless QoS MAC scheduler power adaptation frequency-hopping OFDM. 1. INTRODUCTION As mobile cellular networks are evolving to carry voice video and data services an all-Internet protocol- IP- based system including a radio access network and a core network akin to the Internet is likely to become the most favorable solution for future wireless .