Timing and symbol alignment in multipoint-to-point communication using orthogonal frequency division multiplexing
US7912138B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 2007 |
| Grant date | Mar 22, 2011 |
| Priority date | — |
| Expiry date | Apr 14, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system is provided. The system includes a plurality of remote units and a host unit that includes a demodulator. Each of the remote units transmits an upstream OFDM signal using a multiple access scheme to the host unit demodulator using at least one of a plurality of orthogonal tones within an OFDM waveform. The host unit receives the upstream OFDM signals from a plurality of the remote units, the tones of the upstream signals being substantially orthogonal when received at the host unit. Portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time. The host unit demodulator demodulates the portions of the upstream OFDM signals. The upstream signals from the remote units each include a plurality of symbols and each remote unit times its upstream signal transmission so that when multiple upstream signals arrive at the host unit the symbols of the multiple upstream signals are aligned.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.