No abstract

This paper considers the problem of subcarrier scheduling in the downlink of multicell OFDMA networks. It proposes a dynamic fractional frequency reuse cell architecture that partitions subcarriers into two groups. One is reused in the whole cell area whereas the other is partitioned into sectors and used orthogonally. The proposed architecture allows dynamic allocation of users to the group of subcarriers. This dynamic allocation of users is different from the existing architectures where users are partitioned according to fixed thresholds. Next, we propose an efficient hierarchical solution which first allocates subcarriers to the groups and next opportunistically schedules subcarriers to the users. The overall scheme allows frequency reuse factor of 1 with reduced inter-cell interference, increased trunking gain and satisfied minimum data rate requirements. Simulation results illustrate the usefulness of the proposed solution.978-1-4244-3062-8/08/$25.00 ©2008 IEEE

Respiratory diseases are the most frequent chronic illnesses in babies and children. Although a vigorous innate immune system is critical for maintaining lung health, a balanced response is essential to minimize damaging inflammation. We investigated the functional and clinical impact of human genetic variants in the promoter of NFKBIA, which encodes IκBα, the major negative regulator of NF-κB. In this study, we quantified the functional impact of NFKBIA promoter polymorphisms (rs3138053, rs2233406, and rs2233409) on promoter-driven protein expression, allele-specific and total NFKBIA mRNA expression, IκBα protein expression, and TLR responsiveness; mapped innate immune regulatory networks active during respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia; and genotyped and analyzed independent cohorts of children with respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Genetic variants in the promoter of NFKBIA influenced NFKBIA gene expression, IκBα protein expression, and TLR-mediated inflammatory responses. Using a systems biology approach, we demonstrated that NFKBIA/IκBα is a central hub in transcriptional responses of prevalent childhood lung diseases, including respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Finally, by examining independent pediatric lung disease cohorts, we established that this immunologically relevant genetic variation in the promoter of NFKBIA is associated with differential susceptibility to severe bronchiolitis following infection with respiratory syncytial virus, airway hyperresponsiveness, and severe bronchopulmonary dysplasia. These data highlight the importance of negative innate immune regulators, such as NFKBIA, in pediatric lung disease and begin to unravel common aspects in the genetic predisposition to bronchopulmonary dysplasia, bronchiolitis, and childhood asthma.