Improved Interference-Free Channel Allocation in Coordinated Multiuser Multiantenna Open-Access Small Cells

© 2016 IEEE. This paper investigates low-complexity joint interference avoidance and desired link improvement for single-channel allocation in multiuser multiantenna access points (APs) for open-access small cells. It is considered that an active user is equipped with an antenna array that can be used to suppress interference sources but not to provide spatial diversity. On the other hand, the operation of APs can be coordinated to meet design requirements, where each of which can unconditionally utilize assigned physical channels. Moreover, each AP is equipped with uncorrelated antennas that can be reused simultaneously to serve many active users. The analysis provides new approaches to exploit physical channels, transmit antennas, and APs to mitigate interference, while providing the best possible link gain to an active user through the most suitable interference-free channel. The event of concurrent service requests placed by active users on a specific interference-free channel is discussed for either interference avoidance through identifying unshared channels or desired link improvement via multiuser scheduling. The applicability of the approaches to balance downlink loads is explained, and practical scenarios due to imperfect identification of interference-free channels and/or the scheduled user are thoroughly investigated. The developed results are applicable for any statistical and geometric models of the allocated channel to an active user, as well as channel conditions of interference users. They can be used to study various performance measures. Numerical and simulation results are presented to explain some outcomes of this paper

Inherited Thrombocytopenia with a Different Type of Gene Mutation: A Brief Literature Review and Two Case Studies

Hereditary thrombocytopenias are rare bleeding disorders, which cause a deficiency of platelets in early infancy. This group of disorders is sometimes associated with abnormal phenotypes, like absence of radius. Diagnosis of this type of thrombocytopenia is usually difficult; other causes of thrombocytopenia, such as immune disorders and infections, must be ruled out. The symptoms of hereditary thrombocytopenia also vary from seldom and mild to severe bleeding and occasionally may first occur in late childhood. In this group of patients, we must differentiate heritable disorders from the acquired types of thrombocytopenia, like immune thrombocytopenic purpura. It is also important to watch for pitfalls to avoid unnecessary and potentially hazardous treatment. Herein, we briefly review the recent literature on hereditary thrombocytopenia and then present the cases of two referred patients. The first case had suffered from persistent thrombocytopenia since early infancy and was diagnosed with congenital amegakaryocytic thrombocytopenia, while the other patient presented with Wiskott - Aldrich syndrome