Pilot use in orthogonal frequency division multiplexing based spread spectrum multiple access systems
US6954481B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 2000 |
| Grant date | Oct 11, 2005 |
| Priority date | — |
| Expiry date | Apr 18, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/71563
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Base station identification and downlink synchronization are realized by employing pilots including known symbols transmitted at prescribed frequency tones in individual ones of prescribed time intervals. Specifically, the symbols used in the pilots are uniquely located in a time-frequency grid, where the locations are specified by periodic pilot tone hopping sequences. In a specific embodiment of the invention, a period of a pilot tone hopping sequence is constructed by starting with a Latin-square based hopping sequence, truncating it over time, and possibly offsetting and permuting it over frequency. Particular examples of pilot tone hopping sequences are parallel slope hopping sequences in which the periodicity of the sequences is chosen to be a prime number of symbol time intervals. In another embodiment of the invention, a notion of phantom pilots is employed to facilitate use of various system parameters while accommodating the above noted pilot tone hopping sequences.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.