Method and apparatus for detecting zero rate frames in a communications system
US6208699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 1999 |
| Grant date | Mar 27, 2001 |
| Priority date | — |
| Expiry date | Sep 1, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W52/26
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Techniques for detecting zero rate frames in a received data transmission. A modulated signal is received and demodulated in accordance with a particular demodulation format to generate demodulated symbols. The demodulated symbols are partitioned into a number of received frames. For each received frame, a quality metric is computed and compared against a threshold value. The threshold value is selected based, in part, on the quality metrics of received frames. Based on the comparison result, the received frame is indicated as being either transmitted and received in error (i.e., erased or bad) or not transmitted at all (i.e., zero rate or empty). The quality metric can relate to an energy of a received frame, a distance between a received frame and a codeword corresponding to the received frame, or other metrics. The threshold value can be selected based on the quality metrics computed for decoded frames or received frames identified as good, and can be dynamically adjusted based on current information available at the receiver. The method is advantageously used in a CDMA communications system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.