Topic:Energy and Spectral Efficient Communications in ARQ and HARQ Systems
Time: 2013年6月24日(星期一)10:00am~11:00am
Venue:信电大楼-225学术厅
Speaker:Prof. Jingxian Wu
Director, Wireless Information Network Lab
University of Arkansas
Abstract:
Energy efficiency (EE) and spectral efficiency (SE) are two essential design metrics for wireless communication systems. Energy efficient communication reduces energy consumption and extends the battery life of wireless terminals. Spectral efficient communication aims at supporting more simultaneous with the scarce spectrum resource. However, EE and SE are often conflicting goals, featuring one of the most fundamental tradeoffs in communication system designs. In this talk, the optimum energy efficient and spectral efficient designs for automatic-repeat-request (ARQ) systems and hybrid ARQ (HARQ) systems are discussed. Three optimum designs are considered: the first scheme maximizes the EE without considering the SE; the second scheme minimizes a new metric, the energy per information bit normalized by the SE; and the third scheme maximizes the EE under the constraint of a minimum SE. The optimum designs are performed by considering a variety of parameters, such as hardware power consumption, coding rate, modulation, bit rate, number of overhead bits, and communication distance. The fundamental EE-SE tradeoff curve is analytically identified via the optimization of the third scheme, and it is shown that the optimum EE is quansiconcave in SE in a type-I ARQ system. The optimum solutions to the first two schemes are special operating points on the EE-SE tradeoff curve.
Biography: