The single frequency network (SFN) can provide a multimedia broadcast multicast service over a large coverage area. However, the application of SFN is still restricted by a large amount of feedback. Therefore, we prop...The single frequency network (SFN) can provide a multimedia broadcast multicast service over a large coverage area. However, the application of SFN is still restricted by a large amount of feedback. Therefore, we propose a multicast resource allocation scheme based on limited feedback to maximize the total rate while guaranteeing the quality of service (QoS) requirement of real-time services. In this scheme, we design a user feedback control algorithm to effectively reduce feedback load. The algorithm determines to which base stations the users should report channel state information. We then formulate a joint subcarrier and power allocation issue and find that it has high complexity. Hence, we first distribute subcarriers under the assumption of equal power and develop a proportional allocation strategy to achieve a tradeoff between fairness and QoS. Next, an iterative water-filling power allocation is proposed to fully utilize the limited power. To further decrease complexity, a power iterative scheme is introduced. Simulation results show that the proposed scheme significantly improves system performance while reducing 68% of the feedback overhead. In addition, the power iterative strategy is suitable in practice due to low complexity.展开更多
To the Editor:Lymphangioleiomyomatosis(LAM)is a rare multi-systemic disease that predominantly affects women and is associated with cystic lung destruction,chylous fluid accumulation,and abdominal tumors.[1]The lung f...To the Editor:Lymphangioleiomyomatosis(LAM)is a rare multi-systemic disease that predominantly affects women and is associated with cystic lung destruction,chylous fluid accumulation,and abdominal tumors.[1]The lung function of LAM patients declines at two to four or more times faster rates than the typical age-related decline.Although the mammalian target of rapamycin(mTOR)inhibitor has shown certain benefits for patients with LAM,treatment options remain limited.[2]Synovitis,acne,pustulosis,hyperostosis,and osteitis(SAPHO)syndrome is a spectrum of heterogeneous diseases characterized by osteoarticular and dermatological manifestations.Nonsteroidal anti-inflammatory drugs(NSAIDs),disease-modifying anti-rheumatic drugs,bisphosphonates,and intra-articular steroids are frequently prescribed but are often insufficient to control disease progression.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 60972076 and 61072052)the National Science and Technology Major Project, China (No. 2010ZX03003-004-03)
文摘The single frequency network (SFN) can provide a multimedia broadcast multicast service over a large coverage area. However, the application of SFN is still restricted by a large amount of feedback. Therefore, we propose a multicast resource allocation scheme based on limited feedback to maximize the total rate while guaranteeing the quality of service (QoS) requirement of real-time services. In this scheme, we design a user feedback control algorithm to effectively reduce feedback load. The algorithm determines to which base stations the users should report channel state information. We then formulate a joint subcarrier and power allocation issue and find that it has high complexity. Hence, we first distribute subcarriers under the assumption of equal power and develop a proportional allocation strategy to achieve a tradeoff between fairness and QoS. Next, an iterative water-filling power allocation is proposed to fully utilize the limited power. To further decrease complexity, a power iterative scheme is introduced. Simulation results show that the proposed scheme significantly improves system performance while reducing 68% of the feedback overhead. In addition, the power iterative strategy is suitable in practice due to low complexity.
文摘To the Editor:Lymphangioleiomyomatosis(LAM)is a rare multi-systemic disease that predominantly affects women and is associated with cystic lung destruction,chylous fluid accumulation,and abdominal tumors.[1]The lung function of LAM patients declines at two to four or more times faster rates than the typical age-related decline.Although the mammalian target of rapamycin(mTOR)inhibitor has shown certain benefits for patients with LAM,treatment options remain limited.[2]Synovitis,acne,pustulosis,hyperostosis,and osteitis(SAPHO)syndrome is a spectrum of heterogeneous diseases characterized by osteoarticular and dermatological manifestations.Nonsteroidal anti-inflammatory drugs(NSAIDs),disease-modifying anti-rheumatic drugs,bisphosphonates,and intra-articular steroids are frequently prescribed but are often insufficient to control disease progression.
