Rate detection in direct sequence code division multiple access systems
US6687233B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1999 |
| Grant date | Feb 3, 2004 |
| Priority date | — |
| Expiry date | Jun 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/08
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method of rate detection at a receiving end of a code division multiple access (CDMA) system, in which system the effective data rate is variably selected at the transmitting end from an applicable rate set including a full rate and lower rates, each lower rate being the full rate divided by a different integer, and encoded symbols are repeated for the lower rates to maintain a constant apparent symbol transmission rate, includes the formation of scaled correlations between data entering a Viterbi decoder, after any required de-repetition, and re-encoded data at each of the possible data rates in the applicable rate set. Rate decision logic sequentially considers the full and lower candidate data rates in descending order, choosing the considered candidate data rate to be the actual data rate if certain conditions are met. A first of the conditions is whether the scaled correlation for the considered data rate plus a predetermined biasing threshold associated therewith is greater than or equal to the largest of the scaled correlations for the other data rates, and a second condition depends on whether CRC checking if available for the considered data rate. If CRC checking is avai…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.