Orthogonality Factor in WCDMA Downlinks in Urban Macrocelluar Environments

Summary, in English

Multipath dispersion leads to the loss of orthogonality between signals transmitted simultaneously on a wide-band code division multiple access (WCDMA) downlink. The orthogonality factor (OF), which models its impact in the link signal-to-interference-plus-noise ratio (SINR) equation, depends - to a large extent - on the power delay profile of the multipath channel between the mobile and its serving base station. We use the comprehensive and general COST259 channel model for urban cellular environments to evaluate the impact on the OF of multipath clusters and distance-dependence of the multipath delay decay time constant, both of which have been observed in several channel measurements. The observed large standard deviation of the OF indicates that using a single value for all users in downlink capacity analyses and simulations, as has been the practice, may lead to erroneous conclusions. We also propose an empirical model to analytically characterize the observed statistics of the OF.

• Author: N Mehta; Andreas Molisch; L Greenstein
• Department/s: Department of Electrical and Information Technology
• Publishing year: 2005
• Language: English
• Publication/Series: IEEE Global Telecommunications Conference, GLOBECOM '05.
• Links: http://dx.doi.org/10.1109/GLOCOM.2005.1578400
• Document type: Conference paper
• Topic: Electrical Engineering, Electronic Engineering, Information Engineering
• Keywords: broadband networks; cellular radio; channel capacity; code division multiple access; multipath channels; radio links
• Conference name: IEEE Global Communications Conference (GLOBECOM), 2005
• Conference date: 2005-11-11 - 2005-12-02
• Conference place: St. Louis, MO, United States
• Status: Published
• ISBN/ISSN/Other: ISBN: 0-7803-9414-3