Multirate wireless data communication system
US5706428A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Jan 6, 1998 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W84/12
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A wireless LAN includes first stations adapted to operate at a 1 or a 2 Mbps data rate and second stations adapted to operate at a 1,2,5 or 8 Mbps data rate. The 1 and 2 Mbps rates use DBPSK and DQPSK modulation, respectively. The 5 and 8 Mbps rates use PPM/DQPSK modulation. All four data rates use direct sequence spread spectrum (DSSS) coding. All transmitted messages start with a preamble and header at the 1 Mbps rate. The header includes fields identifying the data rate for the data portion of the message, and a length field. For a 2 Mbps transmission the length field identifies the number of bytes in the data field. For a 5 or 8 Mbps the length field identifies the number of bytes in the data field which, if transmitted at 2 Mbps, would take the same transmission time of the data field, and is thus a fraction 2/5 or 2/8 of the actual number of the bytes. With this arrangements, all the stations are interoperable in a co-existent manner in the LAN.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.