Wireless terminal methods and apparatus for DC tone special treatment
First Claim
1. A method of operating a wireless terminal in a frequency division multiplexed system wherein signals are transmitted in a passband by a base station, the method comprising:
- receiving a passband signal;
converting said received passband signal to a baseband signal, a DC tone existing in said baseband, the DC tone corresponding to a corresponding tone in said passband signal, the baseband signal including additional baseband tones corresponding to additional passband tones; and
performing a signal measurement on said DC tone during a DC tone noise measurement period to generate a DC noise measurement value.
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Accused Products
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.
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Citations
18 Claims
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1. A method of operating a wireless terminal in a frequency division multiplexed system wherein signals are transmitted in a passband by a base station, the method comprising:
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receiving a passband signal;
converting said received passband signal to a baseband signal, a DC tone existing in said baseband, the DC tone corresponding to a corresponding tone in said passband signal, the baseband signal including additional baseband tones corresponding to additional passband tones; and
performing a signal measurement on said DC tone during a DC tone noise measurement period to generate a DC noise measurement value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A wireless terminal for use in a frequency division multiplexed system wherein signals are transmitted in a passband by a base station, the wireless terminal comprising:
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a receiver for receiving passband signals;
a passband to baseband signal conversion module for converting said received passband signals to baseband signals, a DC tone existing in said baseband signals, the DC tone corresponding to a corresponding tone in said passband signals, the baseband signals including additional baseband tones corresponding to additional passband tones; and
a signal measurement module for performing a signal measurement on said DC tone during a DC tone noise measurement period to generate a DC noise measurement value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification