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Macrocell-Wide Behavior of the Orthogonality Factor in WCDMA Downlinks

Mehta, N B ; Molisch, Andreas LU and Greenstein, L (2006) In IEEE Transactions on Wireless Communications 5(12). p.3394-3399
Abstract
The orthogonality factor (OF) quantifies the loss of orthogonality between the signals transmitted simultaneously on a wideband code division multiple access (WCDMA) downlink due to multipath dispersion. It is one of the fundamental parameters that determines the signal-to-interference-plus-noise ratio at the output of the Rake receiver and, consequently, it has a significant impact on downlink system capacity. The OF depends greatly on the delay profile of the multipath channel between the mobile and its serving base station; this profile varies considerably from one location in the cell to another. In this paper, we study how the statistical properties of the small-scale-fading-averaged OF vary over the entire macrocellular area. We use... (More)
The orthogonality factor (OF) quantifies the loss of orthogonality between the signals transmitted simultaneously on a wideband code division multiple access (WCDMA) downlink due to multipath dispersion. It is one of the fundamental parameters that determines the signal-to-interference-plus-noise ratio at the output of the Rake receiver and, consequently, it has a significant impact on downlink system capacity. The OF depends greatly on the delay profile of the multipath channel between the mobile and its serving base station; this profile varies considerably from one location in the cell to another. In this paper, we study how the statistical properties of the small-scale-fading-averaged OF vary over the entire macrocellular area. We use an ensemble of channel profiles at different locations in a cell generated from an implementation of the comprehensive COST259 channel model, which incorporates results from several experimental investigations. We show that the small-scale-fading-averaged OF is itself a random variable whose statistics depend on the mobile's distance from its serving base station. The large observed variance 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. Finally, we propose a simple model that closely matches the statistics of the OF as a function of mobile-to-base distance, thus obviating the need to set up the complicated channel model every time OF values are to be generated. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
wideband code division multiple access, land mobile, fading channels, multipath channels, radio propagation factors, Rayleigh channels, Rake receivers, cellular radio, COST259, channel profile, time-varying channels, statistics, radio receivers, orthogonality factor
in
IEEE Transactions on Wireless Communications
volume
5
issue
12
pages
3394 - 3399
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • wos:000242982400013
  • scopus:33845653515
ISSN
1536-1276
DOI
10.1109/TWC.2006.256962
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Department of Electroscience (011041000)
id
e975779f-7b35-462f-8c5e-a10178011850 (old id 601061)
date added to LUP
2016-04-01 15:32:15
date last changed
2021-02-17 05:53:47
@article{e975779f-7b35-462f-8c5e-a10178011850,
  abstract     = {The orthogonality factor (OF) quantifies the loss of orthogonality between the signals transmitted simultaneously on a wideband code division multiple access (WCDMA) downlink due to multipath dispersion. It is one of the fundamental parameters that determines the signal-to-interference-plus-noise ratio at the output of the Rake receiver and, consequently, it has a significant impact on downlink system capacity. The OF depends greatly on the delay profile of the multipath channel between the mobile and its serving base station; this profile varies considerably from one location in the cell to another. In this paper, we study how the statistical properties of the small-scale-fading-averaged OF vary over the entire macrocellular area. We use an ensemble of channel profiles at different locations in a cell generated from an implementation of the comprehensive COST259 channel model, which incorporates results from several experimental investigations. We show that the small-scale-fading-averaged OF is itself a random variable whose statistics depend on the mobile's distance from its serving base station. The large observed variance 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. Finally, we propose a simple model that closely matches the statistics of the OF as a function of mobile-to-base distance, thus obviating the need to set up the complicated channel model every time OF values are to be generated.},
  author       = {Mehta, N B and Molisch, Andreas and Greenstein, L},
  issn         = {1536-1276},
  language     = {eng},
  number       = {12},
  pages        = {3394--3399},
  publisher    = {IEEE - Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Wireless Communications},
  title        = {Macrocell-Wide Behavior of the Orthogonality Factor in WCDMA Downlinks},
  url          = {http://dx.doi.org/10.1109/TWC.2006.256962},
  doi          = {10.1109/TWC.2006.256962},
  volume       = {5},
  year         = {2006},
}