Filtering identifier for an ofdm system
AssigneeThomson Licensing
InventorsJohn Sidney STEWART, Loic FONTAINE, Anthony PESIN
Life of this patent
Estimating the term…
Abstract
A broadcast TV signal is a DVB-T2 based system. A DVB-T2 transmitter checks OFDM symbols before transmission to determine a level of adjacent channel interference (ACI). If the of level of ACI is too high, i.e., above a threshold value, the OFDM symbols are filtered before transmission. Otherwise, the OFDM symbols are transmitted without filtering. A filtering field is added to an LI pre-signaling table of the broadcast DVB-T2 signal to signal a DVB-T2 receiver when the received OFDM symbols have been filtered.
Claims14
A receiver comprising:
- an orthogonal frequency division multiplexed (OFDM) receiver for receiving an OFDM broadcast signal, the received OFDM broadcast signal conveying frames, each frame comprising a preamble portion and a following data portion;
- wherein a least one preamble portion conveys information to the receiver if a following data portion has been filtered prior to transmission;
- and
- a processor, responsive to the information if a following data portion has been filtered prior to transmission, for controlling a filter to process the following data portion to compensate for the filtering prior to transmission.
A method for use in a receiver, the method comprising:
- receiving an orthogonal frequency division multiplexed (OFDM) broadcast signal, the received OFDM broadcast signal conveying frames, each frame comprising a preamble portion and a following data portion;
- wherein a least one preamble portion conveys information to the receiver if a following data portion has been filtered prior to transmission;
- and
- responsive to the information if a following data portion has been filtered prior to transmission, filtering the following data portion to compensate for the filtering prior to transmission.
An apparatus for transmitting an orthogonal frequency division multiplexed (OFDM) broadcast signal, the apparatus comprising:
- an adjacent channel interference (ACI) estimator for estimating a level of ACI for the OFDM broadcast signal;
- and
- a filter for selectively filtering the OFDM broad signal when the level of ACI is higher than a threshold value.
A method for use in a transmitter for transmitting an orthogonal frequency division multiplexed (OFDM) broadcast signal, the method comprising:
- estimating a level of adjacent channel interference (ACI) for the OFDM broadcast signal;
- and
- selectively filtering the OFDM broad signal when the level of ACI is higher than a threshold value.
Dependencies are inferred from the claim text.