Zhang Zhongzhao

TOA estimation for UWB through-wall application

The wall filter effect on the UWB through-wall impulse is investigated. The problem addressed is the TOA estimation error for the UWB indoor application. Simulation and analysis point out that it is advisable to employ the proper impulse to achieve the high time resolution rather than to employ the impulse as short as possible. The high time resolution and distortion by wall filter effect should be trade off and well considered when the impulse is chosen for the through-wall application. The shorter through-wall impulse it is, the greater distortion it suffers. For templates mismatching with the received signal, the receiver estimates the wrong TOA against the peak of the correlation. The proposed solution is to modify the template according to the application scenarios for different wall materials. Mathematical analysis is exploited to show the validity of this method.

Simplified calculation of UWB signal transmitting through a finitely conducting slab

Abstract A simplified closed-form analytic solution for UWB impulse signal transmitting through a finitely conducting slab is proposed. The approach first requires evaluating the impulse response of the slab and then convolving it with the specified incident field waveform. To obtain the impulsive transmitting field, either for vertical or horizontal polarization, approximations to the refraction coefficients and propagation loss are made, which can be proved to be accurate enough, comparing with their frequency domain solutions. Thereby, it permits simplified closed-form expressions in the time domain for both terms. The resulting transient response for the transmitting impulse field is then given by convolution of the time domain refraction coefficients and time domain propagation loss. A numerical example of an incident monocycle transmitting through a slab using this technique, is presented, to illustrate the effective use of the method.

Interference Mitigated Receiver Based on Base Station Cooperation

Base station cooperation can mitigate interference of other cell in the uplink, in this paper future base stations cooperation architecture and information exchange scheme are proposed, receiver based on base station cooperation is designed, each station detected the weak signal information of users, which are transmitted to cooperative base station to combine and send demodulated signal to local base station. Meanwhile, in receiver, cooperation priority is analyzed which can reduce delay and improve throughput. The proposed receiver can efficiently mitigate OCI to improve system performance, providing new ideas for base station cooperation applying to realistic network.

Design consideration of multi-band RF CMOS filter based on active inductors

In this paper, topology of gyrator-C active inductors are briefly reviewed. A novel structure of multi-band RF active inductor using transistors is presented. Issues of the active inductor related to stability, Q-enhancement principle, and noise are considered. The design of the multi-band Q-enhancement RF filter with 0.18um CMOS process is achieved based on the active inductors. Simulated results show the filter centered at 2.48GHz with about 84MHz bandwidth (3-dB) is tunable in frequency from about 2.19GHz to 4.14GHz, and it exhibits −6.1dBm input third-order intercept point at 2.48GHz with about 80MHz bandwidth while the DC power consumes only 3.9mW.

Information Exchange in the Process of Establishing on Base Station Cooperation

Base station cooperation has been identified as promising features of reducing cell interference and increasing capacity. Main cooperative strategy is the information exchange processed by a cooperative base station or control center, However, the set up of communication procedure was the premise of the application of any cooperation strategy. Measurement, decision, and realization processing are presented based on base station cooperation in this paper. The Influence of base station cooperation on Soft handover is analyzed. The design of scheme indicates that base station cooperation avoid unnecessary handover, which is carried out more exactly, effectively; target cell is chosen more ideal. The results show that we can achieve improved system throughput.

Deconvolution techniques for characterizing indoor UWB wireless channel

Abstract A deconvolution algorithm is proposed to account for the distortions of impulse shape introduced bypropagation process. By finding the best correlation of the received waveform with the multiple templates, thenumber of multipath components is reduced as the result of eliminating the “phantom paths”, and the capturedenergy increases. Moreover, it needs only a single reference measurement in real measurement environment (do notneed the anechoic chamber), which by far simplifies the templates acquiring procedure.

Satellite constellations summary, analysis and design for China mobile satellite communication

We proposed and studied a number of methods of satellite constellation design for regional mobile satellite communication (MSC), and obtained some useful results for Chinas regional MSC. These methods of constellation design can also be applied for other regional mobile satellite communication systems.

The Design and Realization of Evaluation Platform Based on Faults Injection in Massive Storage

A platform including a set of evaluation tools is designed in this paper aimed at the research of fault tolerance and availability in multi-levels Massive Storage. The platform implements faults injection on network drive level and distribution file system level. Then the evaluation results can be obtained from the analysis results after fault injected. On the network drive level, I/O faults pattern in SCSI disk are defined. SCSI instructions are modified in order to simulate SCSI disk faults by intercepting functions in SCSI medium and bottom layer. On distribution file system level, faults assembly involves most faults in server layer, catalog layer and file layer. The test targets system is modified including service continuity, outward service latency time, and performance demotion ratio from which systems can be compared. The platform has been used for our project testing. From the testing results, different fault tolerance and availability can be obtained in different storage system effectively.

Research of VLF ground-penetrating signal receiving technology based on matched filtering

This paper studies on the receiving technique of the very low frequency (VLF) ground-penetrating communication system, and verifies that the matched filtering technology based on the VLF signals receiving system can effectively alleviate the difficulties when receiving the low frequency signals. Then the systems statistic Bit Error Rate (BER) model is built, and the simulation result is analyzed.

Passive location accuracy analysis in bearing-only constellation system

Position location in three-dimensional (3-D) scenarios is studied in bearing-only location system. Through mathematical calculation in 2-D scenarios, the relationship between location accuracy and observation geometry is discussed, and the optimal location geometry relationship and the lowest GDOP in the whole observation region are presented. Finally, the relationship between GDOP and the bearing measurements of passive sensors is shown in the simulation results. GDOP distribute figures under various observation geometry condition are plotted. Some conclusions can be used for reference in designing passive location constellations and collocating passive sensors to improve location accuracy.