The initial cell search plays an important role during the process of downlink synchronization establishment between the User Equipment(UE) and the base station. In particular, the uncertainty of the synchronization s...The initial cell search plays an important role during the process of downlink synchronization establishment between the User Equipment(UE) and the base station. In particular, the uncertainty of the synchronization signals on the frequency domain and the flexibility of frame structure configuration have brought great challenges to the initial cell search for the fifth-generation(5G) new radio(NR). To solve this problem, firstly, we analyze the physical layer frame structure of 5G NR systems. Then, by focusing on the knowledge of synchronization signals, the 5G NR cell search process is designed, and the primary synchronization signal(PSS) timing synchronization algorithm is proposed, including a 5G-based coarse synchronization algorithm and conjugate symmetry-based fine synchronization algorithm. Finally, the performance of the proposed cell search algorithm in 5G NR systems is verified through the combination of Digital Signal Processing(DSP) and personal computer(PC). And the MATLAB simulation proves that the proposed algorithm has better performance than the conventional cross-correlation algorithm when a certain frequency offset exists.展开更多
With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)...With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)and H2O?2-butanol,were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite.In order to determine the optimal process conditions,the effects of various experimental variables,such as reaction temperature,reaction time,catalyst dosage,volume of organic solvent,as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail.It was found that under optimal reaction conditions,H2O?THF,H2O?2-butanol and H2O?MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%,59%,and 50%,respectively.Moreover,in the three biphasic systems,the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability.Thus,the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.展开更多
基金partially the Chongqing Municipality’s Major Theme Project “R & D and Application of 5G terminal simulation equipment” (Grant No. Cstc2017zdcy-zdzx0030)
文摘The initial cell search plays an important role during the process of downlink synchronization establishment between the User Equipment(UE) and the base station. In particular, the uncertainty of the synchronization signals on the frequency domain and the flexibility of frame structure configuration have brought great challenges to the initial cell search for the fifth-generation(5G) new radio(NR). To solve this problem, firstly, we analyze the physical layer frame structure of 5G NR systems. Then, by focusing on the knowledge of synchronization signals, the 5G NR cell search process is designed, and the primary synchronization signal(PSS) timing synchronization algorithm is proposed, including a 5G-based coarse synchronization algorithm and conjugate symmetry-based fine synchronization algorithm. Finally, the performance of the proposed cell search algorithm in 5G NR systems is verified through the combination of Digital Signal Processing(DSP) and personal computer(PC). And the MATLAB simulation proves that the proposed algorithm has better performance than the conventional cross-correlation algorithm when a certain frequency offset exists.
基金Project(3207049713)supported by the Scientific Research Foundation of Graduate School of Southeast University,China
文摘With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)and H2O?2-butanol,were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite.In order to determine the optimal process conditions,the effects of various experimental variables,such as reaction temperature,reaction time,catalyst dosage,volume of organic solvent,as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail.It was found that under optimal reaction conditions,H2O?THF,H2O?2-butanol and H2O?MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%,59%,and 50%,respectively.Moreover,in the three biphasic systems,the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability.Thus,the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.
