Jinbao Zhang

Hybrid TOA/AOA Cooperative Localization in Non-Line-of-Sight Environments

The majority of the location estimation error in wireless communication systems comes from the effect of non-line-of-sight (NLOS) propagation. NLOS identification and correction are the main techniques of mitigating the NLOS impact on positioning accuracy. In this paper, we propose a cooperative localization algorithm that combines the hybrid time of arrival (TOA) / angle of arrival (AOA) measurements of all identified Line-of-Sight (LOS) base station (BS) - mobile station (MS) links with the TOA measurements of MS-MS links. Different cost functions are described according to the NLOS detection results based on existing identification methods. A NLOS correction model is also presented when the destination MS to be located is completely in NLOS propagation, whereas some BS - cooperative MS links are in LOS conditions. Simulation results demonstrate that the proposed algorithm outperforms other existing hybrid localization techniques, and its accuracy increases with the number of LOS BS-MS links, as well as the NLOS detection accuracy.

Fingerprinting localization based on affinity propagation clustering and artificial neural networks

Fingerprinting localization techniques have been intensively studied in indoor WLAN environment. Artificial neural networks (ANN) based fingerprinting technique could potentially provide high accuracy and robust performance. However, it has the limitations of slow convergence, high complexity and large memory storage requirement, which are the bottlenecks of its wide application, especially in the case of a large-scale indoor environment and the terminal with limited computing capability and memory resources. In this paper, we firstly introduce affinity propagation (AP) clustering algorithm to reduce the computation cost and memory overhead, and then explore the properties of radio basis function (RBF) neural networks that may affect the accuracy of the proposed fingerprinting localization systems. We carry out various experiments in a real-world setup where multiple access points are present. The detailed comparison results reveal how the clustering algorithm and the neural networks affect the performance of the proposed algorithms.

Overview of received signal strength based fingerprinting localization in indoor wireless LAN environments

In recent years, indoor localization technique is anticipated to play an increasingly important role in our society. In general, the indoor localization techniques include trilateral, triangulation and fingerprinting localization. As an important alternative, fingerprinting localization techniques are extensively studied and applied in the existing localization systems. This paper presents an overview of the fingerprinting localization system based on the received signal strength (RSS) in indoor wireless LAN (WLAN) environments. In particular, we describe the structure of localization system and then analyze the challenges that most existing research works try to deal with. Corresponding solutions and several pattern matching algorithms are also presented. Furthermore, we demonstrate a comparative study of existing fingerprinting localization systems and address the possible directions of future research in indoor localization techniques.

Regional propagation model based fingerprinting localization in indoor environments

In this paper, we present a novel indoor propagation model for use in a wireless LAN (WLAN) based fingerprinting localization system. This model is based on a derivation of the free space propagation model taking into account the penetration loss and geographic propagation factors in different regions of the indoor structure. The objective of the model is to reconstruct the collected sparse fingerprinting database, eliminating the workload in the offline data collection phase. In the online phase, weighted K-nearest neighbor (WKNN) is adopted to obtain the final location estimation. We have carried out various experiments in a real-world setup to show the performance improvement of the proposed algorithm. Results show that proposed propagation model obtains more accurate prediction of the received signal strength values than other traditional models, delivering a high localization accuracy of up to 1.4 meter.

An anti-interference method for radio signals based on matching pursuit algorithm

Since the GSM-R (Global System for Mobile communications-Railways) antenna located on the train roof is very close to the catenary, it often receives electromagnetic transient disturbance due to sliding contact between the pantograph and the catenary. In order to suppress this transient noise and improve the reliability of communication, a transient noise suppressing method for radio signals based on matching pursuit algorithm is proposed. Firstly, An over-complete atomic library that matches only the transient noise in the mixed radio signal is constructed to implement the sparse decomposition of the transient noise. Then, the optimal matching atomic search of the transient noise is proceeded in the atomic library. In this paper, the GMSK modulation signal in GSM-R system is used as the radio signal to be denoised from the transient noise. The simulation results show that this method can effectively deal with the transient noise denoising problem of the radio signal with a high accuracy result and a low distortion of the radio waveform which keeps the original characteristics of the radio signal, the bit error rate of the radio signal polluted by transient noise is significantly reduced after the processing of the algorithm proposed.

Analytical Computation of Information Rate for MIMO Channels

Information rate for discrete signaling constellations is significant. However, the computational complexity makes information rate rather difficult to analyze for arbitrary fading multiple-input multiple-output (MIMO) channels. An analytical method is proposed to compute information rate, which is characterized by considerable accuracy, reasonable complexity, and concise representation. These features will improve accuracy for performance analysis with criterion of information rate.

The vector perturbation precoding for massive multiple-input multiple-output based on GMD

In this paper, we think about the massive multiple-input multiple-output system analysis of vector perturbation precoding based on channel matrix geometric mean decomposition employing the minimum mean square error criterion with instantaneous power constraints for broadcast channels. Our analysis assumes that the transmitter has the imperfect channel state information and the receivers are acquainted with a perfect channel-dependent transmit power normalization factor. We propose a descent method by iteration for searching the perturbation vector in the complex field. The performances of the devised precoding scheme with the large quantity of transmit antennas and single-antenna users are studied in respect to bit error rate analysis through simulations and the numerical results illustrate it appropriated for massive multiple-input multiple-output system both in terms of complexity and performance.

Analysis of crosstalk between cables on board in high speed EMUs

Due to intensive cable arrangement in high speed EMUs, the work on crosstalk coupling between power lines to temperature sensor lines with groove is quite important. According to a specific cable arrangement on board in EMU, this paper deals with the influence of structure of groove, intersection angle and impedance of lines by electromagnetic simulation software which was based on Finite Difference Time Domain (FDTD). In the light of actual situation, using 110V sinusoidal voltage as excitation source of power line. The results suggested that the metal structure of groove can reduce the maximum crosstalk 13dB, the cover and clapboard of groove can also reduce some crosstalk. In addition, the crosstalk value declines with the intersection angle increased and impedance of cables decreased.

Research on the electromagnetic protection of high voltage cables in high speed EMU of power frequency magnetic field

Aiming at protect passengers with portable pacemaker, it is of vital importance to meet the standard in the design of EMU. In this paper, based on the theory of high voltage cable and electromagnetic protection, the model of high voltage cable passing through the compartment is established to simulate the magnetic flux density of the environment around the cable. In view of the actual situation, using sine, harmonic and inrush current as excitation source of high voltage cable under power frequency magnetic field. The results show that, under these conditions the magnetic field of the high voltage cable cannot affect the normal operation of pacemaker and the length of wire which is without shielding layer should be reduced as much as possible.

The APD statistical analysis of the high-speed system electromagnetic noise

This paper mainly discusses the power network offline noise of high-speed railway system, and uses the MATLAB simulation analysis on its amplitude probability distribution. The results show that the characteristics of the noise mentioned in this article is consist with the theoretical model of the high-speed railway system. It can be used to study the effects of such noise on the high-speed system.