Parameter estimation in VAMOUS receivers
First Claim
1. A method of controlling a receiver in a wireless communication network, the method comprising:
- receiving a desired signal on a first subchannel of a quadrature modulated carrier;
receiving an interfering signal on a second subchannel of the quadrature modulated carrier;
computing a power imbalance ratio indicative of a power distribution between the first and second subchannels; and
if the power imbalance ratio is greater than a threshold;
demodulating the interfering signal to obtain demodulated soft bits corresponding to the interfering signal;
estimating a receiver control parameter from the demodulated symbols corresponding to the interfering signal, wherein the receiver control parameter comprises one of a frequency error, timing error, Doppler shift and receiver gain; and
controlling the wireless terminal based on the control parameter.
1 Assignment
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Accused Products
Abstract
A desired signal and interfering signal are transmitted in the same timeslot and on the same frequency using an Adaptive Quadrature Phase Shift Keying (AQPSK) modulated carrier. When the Sub-Channel Power Imbalance Ratio (SCPIR) for the AQPSK modulated carrier is large and favors the interfering signal, the interfering signal is demodulated first to obtain demodulated soft bits. The demodulated soft bits corresponding to the interfering signal are then used to estimate receiver control parameters, such as Doppler shift, frequency offset, timing error, gain, etc. Using the demodulated soft bits corresponding to the interfering signal improves the accuracy of the receiver control parameters when the SCPIR is large, and results in better overall performance of the receiver.
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Citations
33 Claims
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1. A method of controlling a receiver in a wireless communication network, the method comprising:
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receiving a desired signal on a first subchannel of a quadrature modulated carrier; receiving an interfering signal on a second subchannel of the quadrature modulated carrier; computing a power imbalance ratio indicative of a power distribution between the first and second subchannels; and if the power imbalance ratio is greater than a threshold; demodulating the interfering signal to obtain demodulated soft bits corresponding to the interfering signal; estimating a receiver control parameter from the demodulated symbols corresponding to the interfering signal, wherein the receiver control parameter comprises one of a frequency error, timing error, Doppler shift and receiver gain; and controlling the wireless terminal based on the control parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A wireless terminal comprising:
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receiver circuits configured to receive a quadrature modulated carrier containing a desired signal on a first subchannel of the quadrature modulated carrier and an interfering signal on a second subchannel of the quadrature modulated carrier; one or more processing circuits configured to; compute a power imbalance ratio indicative of the power distribution between the first and second subchannels; if the power imbalance ratio is greater than a threshold, demodulate the interfering signal to obtain demodulated soft bits corresponding to the interfering signal; and estimate a receiver control parameter from the demodulated symbols corresponding to the interfering signal, wherein the receiver control parameter comprises one of a frequency error, timing error, Doppler shift and receiver gain; and a control circuit configured to control the wireless terminal based on the control parameter. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification