Spread spectrum-time diversity communications systems and transceivers for multidrop area networks
US5168510A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1989 |
| Grant date | Dec 1, 1992 |
| Priority date | — |
| Expiry date | Apr 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2203/5495
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Messages are transmitted on pairs of frequencies that are orthogonal, that is the frequencies have no least common denominator (are prime to each other). A message is transmitted on the first of the pair of frequencies and, simultaneously, its complement is transmitted on the second of said pair of frequencies. The message is then retransmitted on another pair of orthogonal frequencies. In the second transmission, the message is remapped, such that, adjacent bits in the first transmission are not adjacent in the second transmission and the same bit in the first transmission and the second transmission are not spaced 1/120th of a second apart. Information is collected on the data error rates at each receiver. This information is periodically transmitted to a central frequency controller which collects this error information and determines the error rates on the frequencies being used. A hill-climbing technique is used to choose pairs of frequencies having the lowest current data error rates. The frequency controller transmits the identity of these frequencies to the various transceivers in each message. The transceivers comprise a frequency controlled carrier frequency generator, ap…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.