Non-orthogonal multiple access (NOMA) achieved the high throughput by introducing the power domain multiplexing. To improve the spectral efficiency of conventional NOMA scheme, we introduce the spatial domain to NOMA and the proposed scheme is proved has superior performance in spectral efficiency, compared with conventional space shift keying (SSK). The result of simulation confirms that the proposed scheme effectively improve the performance in the aspect of spectral efficiency.
Population aging is a serious problem nowadays in many countries. This creates a huge demand of long-term health care. In many long-term care institutes, a caregiver has to take care of many elderly people at the same time. Some of them have been paralyzed in bed, while others are still able to move in the institutes. It is not uncommon that a caregiver has to spend a lot of time to find an elder to perform daily care operations, such as injections, medications, and blood pressure measuring. Elders may move in dangerous places, such as kitchens, stairs, and bathrooms. In this paper, we present an iBeacon-based indoor positioning system for long-term care institutes. Thus, the staffs of long-term care institutes can easily locate the elders, and be notified when some elders move in dangerous places.
The leap development of Internet gives computer science infinite possibility. Meanwhile, the emerging cloud computing has become a tremendous boost of Internet innovation. It alters the traditional IT service models to a remote service and provides massive storage without the limitation of computer processing capacity. This unique storing service paradigm apparently brings a series of benefits and convenience to most Internet enterprises especially start-ups. However, few attentions have been paid to the potential security issues and challenges with the rapid development of cloud computing. During the frequent processing between cloud providers and users, cloud security has been cited as a vital problem as cloud computing outputs data in a virtual environment through the internet. Virtual computing is more vulnerable to various attacks such as data loss and leakage. Hence, comprehensive solutions are significantly necessary to solve these problems in cloud systems. In this paper, we will briefly introduce the definition of cloud computing firstly. And cloud security structure is given in the second part, which includes three main cloud types and three service models. Moreover, crucial security threats and challenges in the cloud computing are illustrated and corresponding solutions are proposed accordingly in the last part.