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AssigneeQUALCOMM Incorporated
InventorsJohn E. Smee, Ivan Jesus Fernandez-Corbaton, Srikant Jayaraman
Estimating the term…
Systems and methods according to the present invention are described for adjusting the number of taps in an adaptive equalizer over time as the rate of change of a communications channel varies. The number of taps or “equalizer length” is adjusted based on an estimate of the Doppler frequency between the devices communicating over a channel. The Doppler frequency is reflective of the rate of change of the communications channel. Greater Doppler frequencies indicate a more quickly varying channel, and vice versa. It is therefore desirable to change the equalizer length (by adding or dropping taps) based on a measurement of the Doppler frequency. Equalizer length is increased as the Doppler frequency decreases. Conversely, equalizer length is decreased as the Doppler frequency increases. This enables the equalizer to achieve a better compromise between the competing goals of adaptation speed (less taps) and ISI reduction (more taps).
In a wireless communications system wherein an equalizer is used to reduce interference on a communications channel, and wherein a Doppler frequency is reflective of a rate of change of the communications channel, a method for adjusting a length of the equalizer comprising increasing the length as the Doppler frequency decreases, and decreasing the length as the Doppler frequency increases.
A method comprising:
An equalizer for reducing interference on a wireless communications channel, wherein a Doppler frequency is reflective of a rate of change of the wireless communications channel, said equalizer comprising:
Dependencies are inferred from the claim text.