Zhihua Lai | University of Bedfordshire (original) (raw)

Papers by Zhihua Lai

Abstract In this article, we propose a new hybrid modeling method for indoor-to-outdoor radio cov... more Abstract In this article, we propose a new hybrid modeling method for indoor-to-outdoor radio coverage prediction. The proposed method is a combination of a ray-optical channel modeling approach and the frequency domain ParFlow method. While the former is widely used for modeling outdoor propagation environments, the latter is computationally efficient and accurate for modeling indoor environments.

Abstract In this paper, a new model used to compute the outdoor to indoor signal strength emitted... more Abstract In this paper, a new model used to compute the outdoor to indoor signal strength emitted by a base station is presented. This model is based on the combination of 2 existing models: IRLA (Intelligent Ray Launching), a 3D geometric-like model especially optimized for outdoor predictions, and MR-FDPF (Multi Resolution Frequency Domain ParFlow), a 2D FDTD-like model initially implemented for indoor propagation.

In this article, we discuss the development of two repositories of shared knowledge using intra-a... more In this article, we discuss the development of two repositories of shared knowledge using intra-and inter-tagging functionality. The functionality enables web user communities to upload, search, navigate through and tag multiple documents in multiple ways at a macro and micro level. Users can tag the whole document as well as parts there-in, as they deem appropriate. Our development process employed a unique, specifically designed community user needs approach (CUNA) to allow elicitation of diverse user communities needs.

Abstract Indoor propagation models attract much interest these days because of their importance i... more Abstract Indoor propagation models attract much interest these days because of their importance in the applications of 3G/4G network planning and optimisation. The accuracy and running speed directly affects the practical use of such models. This paper extends a discrete ray launching model IRLA (Intelligent Ray Launching Algorithm) to indoor scenarios. A typical office room will be selected to validate this model.

Abstract This paper investigates the influence of the human body on indoor measurements of radio ... more Abstract This paper investigates the influence of the human body on indoor measurements of radio wave path loss at 3.5 GHz and proposes a solution to improve the accuracy of measurement. The presence of the human body causes measurement errors to radio wave field strength, which is of concern for analysis. The reduction of errors due to measurement process enhances the accuracy of measurement data that is used to validate propagation models.

Page 1. G. de la Roche et al, PIERS 2011, Marrakech Antenna Height Compensation for an Indoor to ... more Page 1. G. de la Roche et al, PIERS 2011, Marrakech Antenna Height Compensation for an Indoor to Outdoor Channel model based on a 2D Finite Difference Model Guillaume de la Roche (1) , Dmitry Umansky (2) , Zhihua Lai (1) , Guillaume Villemaud (2) , Jean-Marie Gorce (2) , and Jie Zhang (3) (1) University of Bedfordshire, Luton, United Kingdom (2) INSA, University of Lyon, Villeurbanne, France (3) University of Sheffield, Sheffield, United Kingdom Page 2. G.

Abstract. This article describes the indoor IRLA (Intelligent Ray Launching Algorithm), which ori... more Abstract. This article describes the indoor IRLA (Intelligent Ray Launching Algorithm), which originates from an efficient outdoor propagation prediction model. Implementation and validation are given in detail. An indoor office scenario is selected and simulations via the IRLA model and two other reference models have been performed. Predictions are analyzed and recommendations are given. Results show that the indoor IRLA model is suitable for indoor wireless network planning and optimization process.

Abstract Ultra-wideband (UWB) receivers can resolve individual multipath components (MPCs), due t... more Abstract Ultra-wideband (UWB) receivers can resolve individual multipath components (MPCs), due to the signal occupied a large bandwidths, so they are capable of accurately estimating the time of flight of the signal. To realize high-accuracy indoor localization, a novel UWB locating scheme through estimating the round trip time (RTT) of UWB signal is proposed. Each reference station (RS) transmits the baseband pulse modulated UWB signals.

ABSTRACT The paper discusses the development of a web based knowledge sharing portal using intra ... more ABSTRACT The paper discusses the development of a web based knowledge sharing portal using intra and inter tagging functionality. This functionality enables multiple users to tag multiple documents in multiple ways at a macro and micro level. Users can upload documents and tag the whole document as well as parts there-in as they deem appropriate, other users can then tag the whole document or specific parts there-in as they deem appropriate.

Abstract Planning and optimizing 3G networks (eg Wideband Code Division Multiple Access, WCDMA) n... more Abstract Planning and optimizing 3G networks (eg Wideband Code Division Multiple Access, WCDMA) needs large amounts of data modelling, parameters adjusting until satisfied conditions are found. It often needs significant computation resources since the problem becomes unmanagedly large if the network size is large (nonpolynomial hard).