Spectral-Energy Efficiency In Simultaneously Wireless Information And Power Transfer

With the development of wireless communication technology and wireless energy harvesting(EH)technology,a new technology which combining wireless information transfer and wireless energy harvesting together,simultaneously wireless information and power transfer(SWIPT)arises at the historic moment.Along with the development of the 5 G mobile communication technology and the widespread use of wireless sensor network,SWIPT will obtain more and more broad application prospects and practical value.On the other hand,with the rapid growth of the number and requirements of mobile communication system users,the available spectrum resources is becoming increasingly tense.In this context,improve spectrum efficiency(SE)and the energy efficiency(EE)of wireless communication system has become an increasingly important research topic,which attracted a large number of researchers and has a large number of relatively mature research results.But there are only a few research results for the spectral efficiency and energy efficiency in SWIPT.In this paper,we would propose the new definition of EE and SE in SWIPT and clarify the trade off and optimization strategies for the EE and SE in SWIPT.In order to clarify the definitions of spectral efficiency and energy efficiency in SWIPT,in this paper,we introduced the concept of SWIPT and its basic principle firstly and established the general system architecture and channel model for a SISO SWIPT system.Then we took advantage of the P2110-EVAL-01 development kits form Powercast company to measure the established system architecture and channel model,and verified the practicability and accuracy of the presented model and architecture.Different from the definitions of spectral efficiency and energy efficiency in the field of traditional wireless communications,in this paper,we would analyze the spectral efficiency and energy efficiency in SWIPT from two aspects:information transmission process and energy harvesting process.We proposed four new definitions of Energy Efficiency and Spectral Efficiency for Simultaneously Wireless Information and Power Transfer systems by taking account of information transmission and energy harvesting process.They are energy efficiency for information transfer,energy efficiency for energy harvesting,spectral efficiency for information transfer,and spectral efficiency for energy harvesting.We selected three main restrictive conditions for a SWIPT system,which are transmitter power supply,available spectrum resources and the battery power in the receiver side.Then we divided the working conditions of a SWIPT system into 8 different situation.The transmit power and splitting factor are selected as the two key parameters influencing energy efficiency and spectral efficiency in Simultaneously Wireless Information and Power Transfer systems.In section four,we proposed 8 different optimization strategies to deal with the tradeoffs between the energy efficiency and spectral efficiency in SWIPT under different external conditions.And we have done some simulation works to demonstrate the effectiveness ofthe optimization strategies in this paper.