Power Aware Routing in Mobile Ad Hoc Networks

This article provides a detailed discussion of wireless resource and channel allocation schemes. The authors provide a survey of a large number of published papers in the area of fixed, dynamic, and hybrid allocation schemes and compare their trade-offs in terms of complexity and performance. We also investigate these channel allocation schemes based on other factors such as distributed/centralized control and adaptability to traffic conditions. Moreover, we provide a detailed discussion on reuse partitioning schemes, the effect of handoffs, and prioritization schemes. Finally, we discuss other important issues in resource allocation such as overlay cells, frequency planning, and power control.

Channel assignment schemes for cellular mobile telecommunication systems: a comprehensive survey

The demand for wireless mobile communications services is growing at an explosive rate, with the anticipation that communication to a mobile device anywhere on the globe at all times will be available in the near future. An array of antennas mounted on vehicles, ships, aircraft, satellites, and base stations is expected to play an important role in fulfilling the increased demand of channel requirement for these services, as well as for the realization of the dream that a portable communications device the size of a wristwatch be available at an affordable cost for such services. This paper is the first of a two-part study. It provides a comprehensive treatment, at a level appropriate to nonspecialists, of the use of an antenna array to enhance the efficiency of mobile communications systems. It presents an overview of mobile communications as well as details of how an array may be used in various mobile communications systems, including land-mobile, indoor-radio, and satellite-based systems. It discusses advantages of an array of antennas in a mobile communications system, highlights improvements that are possible by using multiple antennas compared to a single antenna in a system, and provides details on the feasibility of antenna arrays for mobile communications applications.

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Applications of antenna arrays to mobile communications. I. Performance improvement, feasibility, and system considerations

A four-component scattering model is proposed to decompose polarimetric synthetic aperture radar (SAR) images. The covariance matrix approach is used to deal with the nonreflection symmetric scattering case. This scheme includes and extends the three-component decomposition method introduced by Freeman and Durden dealing with the reflection symmetry condition that the co-pol and the cross-pol correlations are close to zero. Helix scattering power is added as the fourth component to the three-component scattering model which describes surface, double bounce, and volume scattering. This helix scattering term is added to take account of the co-pol and the cross-pol correlations which generally appear in complex urban area scattering and disappear for a natural distributed scatterer. This term is relevant for describing man-made targets in urban area scattering. In addition, asymmetric volume scattering covariance matrices are introduced in dependence of the relative backscattering magnitude between HH and VV. A modification of probability density function for a cloud of dipole scatterers yields asymmetric covariance matrices. An appropriate choice among the symmetric or asymmetric volume scattering covariance matrices allows us to make a best fit to the measured data. A four-component decomposition algorithm is developed to deal with a general scattering case. The result of this decomposition is demonstrated with L-band Pi-SAR images taken over the city of Niigata, Japan.

Four-component scattering model for polarimetric SAR image decomposition

Four-Component Scattering Model for Polarimetric SAR Image Decomposition based on Asymmetric Covariance Matrix(Remote sensing/Radar (2), Workshop for Space, Aeronautical and Navigational Electronics (WSANE 2005))

Location Problems on Undirected Flow Networks

Microwave transmission loss in a natural snowpack was measured to provide fundamental data for snow subsurface radar. The snowpack consisted of many horizontal stratified layers of relatively large density and water inclusion. Field strength measurements were carried out in the vertical direction across horizontal snow layers in the frequency range 0.6-7.0 GHz. The transmission loss and the extinction coefficients were obtained as a function of frequency. >

Experimental study of microwave transmission in snowpack

Traffic characteristics of a mobile radio communication system using a dynamic channel assignment scheme which has all channels available at all base stations are derived. In the system with one channel, the traffic characteristics in each zone are exactly obtained. For a multichannel operation, some approximation methods are proposed and some simple examples are also presented.

Masakazu Sengoku

Papers

Location Problems on Undirected Flow Networks

Experimental study of microwave transmission in snowpack

On Telephone Traffic in a Mobile Radio Communication System Using Dynamic Frequency Assignments

Some Covering Problems in Location Theory on Flow Networks

Channel assignment problem in a cellular mobile system and a new coloring problem of networks