T-spaced equalization for 1xEV systems
US6856646B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2002 |
| Grant date | Feb 15, 2005 |
| Priority date | — |
| Expiry date | Sep 3, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03509
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention relates to systems and methods that facilitate compensating for intersymbol interference (e.g. due to non-nyquist filtering) in Code Division Multiple Access (CDMA) systems (e.g., IS 95 and IS2000 systems). The subject invention employs equalization filters (e.g., T-spaced equalizers) at fingers of a RAKE receiver. By effecting such equalization filtering at a downstream point in a receiving system, e.g., at the fingers of the RAKE receiver, the filters can be run so as to operate at lower rates as compared to conventional systems where filtering is effected upstream where time is not necessarily known thus requiring equalization filters to operate at significantly faster rates (e.g., 2× or 4× expected chip rate). Accordingly, as compared to conventional systems where the matching filters often are of substantial complexity (e.g., >80 taps) the present invention provides for less complex equalization filters thereby reducing overall system complexity and cost.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.