On Node Density ? Outage Probability Tradeoff in Wireless Networks

A statistical model of interference in wireless networks is considered, which is based on the traditional propagation channel model and a Poisson model of random spatial distribution of nodes in 1-D, 2-D and 3-D spaces with both uniform and non-uniform densities. The power of nearest interferer is used as a major performance indicator, instead of a traditionally-used total interference power, since at the low outage region, they have the same statistics so that the former is an accurate approximation of the latter. This simplifies the problem significantly and allows one to develop a unified framework for the outage probability analysis, including the impacts of complete/partial interference cancelation, of different types of fading and of linear filtering, either alone or in combination with each other. When a given number of nearest interferers are completely canceled, the outage probability is shown to scale down exponentially in this number. Three different models of partial cancelation are considered and compared via their outage probabilities. The partial cancelation level required to eliminate the impact of an interferer is quantified. The effect of a broad class of fading processes (including all popular fading models) is included in the analysis in a straightforward way, which can be positive or negative depending on a particular model and propagation/ system parameters. The positive effect of linear filtering (e.g. by directional antennas) is quantified via a new statistical selectivity parameter. The analysis results in formulation of a tradeoff relationship between the network density and the outage probability, which is a result of the interplay between random geometry of node locations, the propagation path loss and the distortion effects at the victim receiver.     

Automated double-frequency testing technique for mapping receiveinterference responses

This paper presents the basic principles of a double-frequency testing technique for highly informative visualization of the linear and nonlinear interference responses of receivers. The technique is implemented with an automated double-frequency test system (DFTS) built around conventional controlling and measuring equipment. The main advantages of DPTS are gained by using the principles of raster-like changing of test signals frequencies combined with visualization of test results as two-dimensional (2-D) raster images of the receiver-under-test double-frequency diagrams (or interference response maps). Basic functionalities of the technique for double-frequency testing, which make possible automated detection and identification of all types of interference in the receiver and measurement of their parameter's, are described. Results of practical implementation of this technique for testing super-high frequency (SHF) receivers, RF amplifiers (RFA) and diode generator are discussed