Weighted autocorrelation method for downlink CDMA LMMSE equalizers
US7443909B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2004 |
| Grant date | Oct 28, 2008 |
| Priority date | — |
| Expiry date | Aug 14, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/71055
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Receiving downlink CDMA signals in a fast-fading environment is facilitated at higher receiver velocities by updating the block-adaptive linear minimum mean square error (LMMSE) downlink CDMA equalizer. The autocorrelation matrix of the observed data is updated by passing block-wise autocorrelation slides through a filter. Each autocorrelation slide is an autocorrelation matrix estimated from a short block of observed data over which the channel can be considered constant. This method achieves a reliable estimate for the autocorrelation matrix when the block size must be small to ensure that the block-wise stationarity assumption holds in cases of fast fading channels. In addition, small block sizes make it possible to satisfy the equalizer delay constraint imposed by hardware and certain voice transmission standards such as CDMA2000 1X where demodulated data must be delivered within only several symbol periods of the signal arrival time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.