Spectrum efficiency for future wireless communications
Date
2015
Authors
Yu, Bo, author
Yang, Liuqing, advisor
Luo, Jie, committee member
Morton, Yu, committee member
Wang, Haonan, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Spectrum efficiency has long been at the center of wireless communication research, development, and operation. Today, it is even more so with the explosive popularity of mobile internet, social networks, and smart phones that are more powerful than our desktops not long ago. As a result, there is an urgent need to further improve the spectrum efficiency in order to provide higher wireless data capacity. To respond to this demand, the 3rd Generation Partnership Project (3GPP) standardized the radio interface specifications for the next generation mobile communications system, called Long Term Evolution (LTE), in Release 8 specifications in 2008. Then the development continued and an enhanced LTE radio interface called LTE-Advanced (LTE-A) was standardized in Release 10 specifications in 2011. In order to ensure the sustainability of 3GPP radio access technologies over the coming decade, 3GPP standardization will need to continue identifying and providing new solutions that can respond to the future challenges. In this research, we investigate the potential technologies for further spectrum efficiency enhancement in the future steps of the standardization. One key direction is the further enhancement of local area technologies, which play a more and more important role in complementing the wide area networks. Specifically, we investigate two promising techniques for spectrum efficiency improvement in a macro-assisted small cell architecture, called the Phantom cell, which is proposed by DOCOMO. One is the possibility of dynamic allocation of subframes to uplink (UL) or downlink (DL) in time-division duplexing (TDD), called `Dynamic TDD'. The other is the more dynamic and flexible 3-dimensional (3D) beamforming which is facilitated by the adoption of active antenna systems (AAS) in BSs. In addition, full-duplex transmission and cooperative communication are two promising techniques known to enhance the spectrum efficiency of wireless communications. We focus on applying full-duplex in cooperative relaying networks and investigating the optimal resource allocation (both power and relay location) for full-duplex decode-and-forward (DF) relaying systems for spectrum efficiency enhancement.