Wireless terminal methods and apparatus for DC tone special treatment
US7539475B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 2005 |
| Grant date | May 26, 2009 |
| Priority date | — |
| Expiry date | Feb 3, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/061
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Special DC tone treatment in a wireless communications system, e.g., an OFDM system, is discussed. In the downlink, a wireless terminal receiver introduces self-interference at the DC tone from the RF/baseband conversion. A base station every so often does not transmit on the downlink DC tone while continuing to transmit on other downlink tones. Wireless terminals measure received signal on the downlink DC tone during the time of suspended DC tone transmission, estimate self-interference and apply a correction to other received downlink DC tones. In the uplink DC tone interference is a composite of the assigned wireless terminal transmitter's baseband/RF conversion self-interference and air link noise. During one symbol interval of an N symbol interval dwell, the uplink DC tone is reserved for a special modulation symbol, which is a predetermined function of the other N−1 modulation symbols. At the base station, its receiver receives a set of modulation symbols conveyed by the uplink DC tone for a dwell, calculates the average DC component and corrects the received N−1 modulation symbols.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.