Code division multiple access communication system using overlapping spread sequences
US6728295B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2000 |
| Grant date | Apr 27, 2004 |
| Priority date | — |
| Expiry date | Jun 23, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/0048
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
This invention discloses a code division multiple access communications system based on spread sequences designed by using complete factorization of polyphase matrix of a perfect reconstruction (PR) filter bank. The key characteristic is that the length of the spread sequence is longer than the period of the data symbol i.e., the data symbols are spreaded by the spread sequence and overlapped with neighboring data symbols. The design method includes an orthogonal code generator, a number of cascading stages and random permutation matrices. The number of cascading stages and random permutation matrices are selected according to the length of the spread sequence required. The length of the spread sequence could be selected according to the system performance requirement, hence the overlapping factor of spreaded data symbols. Furthermore, this spread sequence assumes integer values instead of binary when the orthogonal code generator generates a Walsh-Hadamard code. The number of integer values level could be limited by employing proper permutation matrices. This spread sequence generation method could be implemented using simple integer arithmetic. Furthermore, This spread sequences …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.