Advanced Materials Research Vols. 760-762

Abstract: In order to provide the large coverage and high data rate in future system, more and more low power nodes (LPNs) e.g., pico nodes, relay nodes, etc., are introduced into the LTE heterogeneous network (HetNet). The resource allocation and optimization scheme is the key issue in Hetnet system since the interference environment is quite complicated compared with the traditional homogenous networks. In this paper, the semi-distributed power and subcarrier allocation scheme is proposed, which aims to achieve the good performance tradeoff between the macro eNBs and the pico nodes. One novel utility function is investigated taking both macro edge UEs and pico edge UEs into account based on limited average data rate information exchanges between macro eNB and pico eNBs. The interference for the edge UEs can be coordinated efficiently due to the dynamic power and subcarrier allocations. Compared with the proportional fairness (PF) scheduling algorithm, the simulation results show that the proposed semi-distributed scheme can achieve about 8% throughput gain in average cell throughput. Furthermore, the pico edge UEs, and macro edge UEs of the proposed scheme can achieve 17%, 12% capacity gain, respectively.

Abstract: A monolithically integrated 10Gbps Vertical Cavity Surface Emitting Laser (VCSEL) current driver is implemented in SMIC 0.18μm RF CMOS technology. High current driving capability as well as agile switching speed is achieved by shunt peaking technique and cascade structure. Test result shows that the driver can drive the common anode VCSEL well working at 10Gbps, and delivers 9.7mA modulation current. With single 1.8V power supply, the core power consumption is 22.5mW and the die size is 800μm×500μm.

Abstract: Erbium-doped fiber source for Fiber Optic Gyro (FOG) uses doped fiber to produce super fluorescence with laser pumping. It has higher output power, wide spectral lines, lower temporal coherence, good temperature stability and long life, which are perfect source for high precision FOG. To solve the problem of reliability analysis of erbium-doped fiber source for FOG with zero failure data, Weibull distribution is chosen as the life distribution model of erbium-doped fiber source on basis of the failure mechanism analysis in this paper. And Bayesian theory is used to estimate the failure rate in different time with zero failure data, then the parameters of the life model are estimated to get reliability index of erbium-doped fiber source. The method greatly decreases the number of test samples because of Bayesian estimation has take advantage of experience information, and also, it overcomes the shortcoming of relying on failure data when using traditional reliability assessment methods. So it has great value on project application.

Abstract: For the study of highly precise simulation algorithm for the analysis of antenna, the basic thought of method of moment analysis of wire antennas is introduced. The mathematical model is established and the formula derivation is presented in this paper. The method of moment equation is solved through utilizing three different basis functions and weight functions. Two examples are given, and the computing results are contrasted with the simulation results of FEKO. The comparison result shows that method of moment is quite accurate when it is used to analyze wire antennas, and the computed results acquired by applying Galerkin matching method are the most accurate of all. In the end, an accurate and effective electromagnetic simulation method is presented.

Abstract: The subject is a research on a terminal which can accomplish the transmission of real-time location information, location, navigation, and communication by the wireless network of a monitoring system. The terminal equipment uses ARM as the microcontroller for extracting the information of GPS position, velocity and time. Then, the information is sent in the form of data packages or text messages by the GSM network and the ISM network of wireless transmission. The solution is stable and easy to control.

Abstract: A 94 GHz waveguide orthomode transducer to be used as a receiver has been designed, fabricated, and measured. The waveguide choke, realized by a cascade of symmetrical steps, is introduced as the polarization discriminator, which could remarkable lower the difficulty of manufacturing and assembling in W-band and above. The designed orthomode transducer has low return loss, high isolation, and moderately broad bandwidth, and its performance closely follow the simulation results.

Abstract: This paper demonstrates the operating characteristics of a ka-band magnetron-type slotted peniotron. The third-harmonic four-vane peniotron operates in a circularly polarized 2π mode. We have compared the results between theoretical analysis and PIC simulation of the peniotron. The results show that, with proper acceleration voltage and beam current, the peniotron is predicted to generate a pure 2π mode electromagnetic wave, and the theoretical analysis predicted and PIC simulation demonstrated output power are as high as 52 kW and 45 kW at 29.7 GHz, respectively.

Abstract: Based on a linearly tapered antipodal finline, a novel low-loss wideband transition between waveguide and substrate integrated waveguide (SIW) is discussed. Results show that a low insertion loss (1.2-2.1dB) and a return loss better than 15dB across the entire Ka-band are obtained for a back-to-back transition structure.

Abstract: This paper proposes an optimal placement strategy of physical nodes of DHT-based systems to minimize the lookup latency and improve the throughput of system. The main idea of our approach is to create a new hierarchy named link space between logical space and physical space of DHT overlay. We firstly give an assignment of link space and then present the optimal placement strategy of placing physical nodes on it based on the given lookup traffic matrix. At last, we use genetic algorithm to solve the optimization problem.

Abstract: A novel high-birefringent photonic crystal fiber (PCF) was proposed and analyzed by full-vector finite element method (FEM). The modal field and birefringence properties were investigated. All of air holes in proposed PCF are round, and their diameters are the same. It is greatly reduce the difficulty of fabrication. According to the results of numerical analysis, it can be observed that the mode birefringence of this novel PCF can be easily achieve the order of 10^-3 at 1.55μm. This research provides effective theoretical method for the fabrication, development and construction of high-birefringence photonic crystal fiber.