Orthogonal frequency division multiplexing based spread spectrum multiple access
US6473418B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1999 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Mar 11, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/026
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access system the entire bandwidth is divided into orthogonal tones, and all of the orthogonal tones are reused in each cell. To reduce peak-to-average ratio at the mobile transmitter, each voice user is allocated preferably a single one, but no more than a very small number, of the orthogonal tones for use in communicating with the base station. Data users are similarly allocated tones for data communication, however, the number of tones assigned for each particular data user is a function of the data rate for that user. The tone assignment for a given user is not always the same within the available band, but instead the tones assigned to each user are hopped over time. More specifically, in the downlink, the tones assigned to each user are change relatively rapidly, e.g., from symbol to symbol, i.e., the user fast “hops” from one tone to another. However, in the uplink, preferably slow hopping is employed to allow efficient modulation of the uplink signal which necessitates the employing of additional techniques, such as interleaving, to compensate for the reduction in the intercel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.