Multiple access method
US5170412A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 21, 1991 |
| Grant date | Dec 8, 1992 |
| Priority date | — |
| Expiry date | Nov 21, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/0022
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a multiple access method for the simultaneous exchange of several data streams ({B.sub.1,m }, {B.sub.2,m }, {B.sub.3,m }) among several participants of a transmission system, various data streams ({B.sub.1,m }, {B.sub.2,m }, {B.sub.3,m }) with the same spread sequence (s[.]) are expanded to a corresponding DSSS signal ({B.sub.1,m s[.]}, {B.sub.2,m s[.]}, {B.sub.3,m s[.]}. During transmission, the various DSSS signals ({B.sub.1,m s[.]}, {B.sub.2,m s[.]}, {B.sub.3,m s[.]}) are heterodyned to a single incoming signal. For detecting the various data streams in a receiver, the incoming signal is filtered in a filter that is inverse with respect to the joint spread sequence (s[.]). In order to permit reliable detection, heterodyning takes place in each case so that the spread sequence intervals pertaining to different data streams are chronologically shifted with respect to one another by a given minimum value (delta.sub.-- T). The invention provides a multiple access method combining therein the advantages of TDMA and CDMA. In particular, an almost complete separation of the users is possible without requiring the precision of synchronization customary in case of TDMA.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.