Communication device and method for interference suppression using adaptive equalization in a spread spectrum communication system
AssigneeMotorola, Inc.
InventorsYevgeny Visotsky, Colin D. Frank, Upamanyu Madhow, Rahul Singh
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Abstract
A communication device such as a mobile station (410) for a spread spectrum communication system includes a receiver (100) having an adaptive equalizer (104) which suppresses interference on a received spread spectrum signal to produce an equalized signal (126). A pilot channel demodulator (110) demodulates the equalized signal to produce an estimate of the pilot channel (140). A summer (112) compares the pilot channel estimate and a predetermined data pattern to produce an error signal (124). A traffic channel demodulator (108) demodulates the equalized signal to produce one or more traffic channels.
Claims33
A communication device for receiving a spread spectrum signal which includes a pilot channel and traffic channels, the pilot channel substantially orthogonal to each of the traffic channels, the communication device comprising:
- an adaptive equalizer which adapts using the pilot channel, the adaptive equalizer receiving the spread spectrum signal and producing an equalized signal;
- a demodulator for demodulating the equalized signal to produce a demodulated traffic channel;
- a pilot channel demodulator which produces a pilot channel estimate;
- and
- a comparator for generating an error signal in response to the pilot channel estimate, the adaptive equalizer adapting in response to the error signal.
A communication device for receiving a spread spectrum signal which includes a pilot channel and traffic channels. the communication device comprising:
- an adaptive equalizer which adapts using the pilot channel, the adaptive equalizer receiving the spread spectrum signal and producing an equalized signal;
- and
- a demodulator for demodulating the equalized signal to produce a demodulated traffic channel
- wherein, when a plurality of traffic channels are assigned for communication to the communication device, the adaptive equalizer produces the equalized signal for each of the plurality of traffic channels and the demodulator selectively demodulates each of the plurality of traffic channels.
A communication device for receiving a spread spectrum signal which includes a pilot channel and traffic channels, the pilot channel and the traffic channels covered using a Hadamard code before transmission so as to be substantially mutually orthogonal, the communication device comprising:
- a minimum mean-square error (MMSE) equalizer which adapts using the pilot channel, the MMSE equalizer receiving the spread spectrum signal and producing an equalized signal, the MMSE equalizer operable to adapt to minimize a mean square error of the equalized signal, the MMSE equalizer substantially the same for all traffic channels for a given channel condition;
- and
- a demodulator for demodulating the equalized signal to produce a demodulated traffic channel.
A spread spectrum communication system comprising:
- a plurality of stationary transmitters which transmit respective spread spectrum signals including two or more signals, a first signal being substantially orthogonal to a second signal, wherein each stationary transmitter transmits a pilot channel and substantially orthogonal traffic channels;
- a receiver which receives spread spectrum signals, the receiver including
- an adaptive equalizer which adapts using the first signal, and
- a demodulator for demodulating the second signal;
- and
- a plurality of mobile receivers including the receiver, the receiver producing an error signal in response to the pilot channel, the adaptive equalizer adapting using the error signal to produce an equalized signal.
A receiver for receiving a spread spectrum signal, the spread spectrum signal including a pilot channel and a plurality of traffic channels, all channels being substantially orthogonal, the receiver comprising:
- an adaptive equalizer for receiving the spread spectrum signal and an error signal, the adaptive equalizer suppressing interference on the spread spectrum signal to produce an equalized signal;
- a traffic channel demodulator for demodulating the equalized signal and producing one or more traffic channels;
- a pilot channel demodulator for demodulating the equalized signal to produce a pilot channel estimate;
- and
- an error signal generator for producing the error signal in response to the pilot channel estimate.
A communication device for a spread spectrum communication system including a plurality of remote transceivers, the communication device comprising:
- a first receiver circuit, including:
- a first adaptive equalizer for receiving first spread spectrum signals from a first base transmitter, suppressing interference and producing a first equalized signal in response to a first error signal,
- a first demodulator for demodulating the first equalized signal to produce traffic signals, and
- a first pilot channel estimator for producing a first pilot channel estimate for the first spread spectrum signals;
- a second receiver circuit, including:
- a second adaptive equalizer for receiving second spread spectrum signals from a second base transmitter, suppressing interference and producing a second equalized signal in response to a second error signal,
- a second demodulator for demodulating the second equalized signal to produce traffic signals, and
- a second pilot channel estimator for producing a second pilot channel estimate for the second spread spectrum signals;
- and
- an error signal generator which produces the first error signal and the second error signal in response to the first pilot channel estimate and the second pilot channel estimate.
A method for controlling soft handoff in a spread spectrum communication system, the method comprising the steps of:
- receiving first spread spectrum signals from a first remote transmitter;
- receiving second spread spectrum signals from a second remote transmitter;
- producing an error signal in response to at least one of the first spread spectrum signals and the second spread spectrum signals;
- adaptively equalizing the first spread spectrum signals and the second spread spectrum signals in response to the error signal to produce a first equalized signal and a second equalized signal;
- demodulating a first traffic channel from the first equalized signal;
- demodulating a second traffic channel from the second equalized signal;
- and
- combining the first traffic channel and the second traffic channel as received data.
A method for receiving radio frequency (RF) signals at a receiver, the method comprising the steps of:
- in an adaptive equalizer, equalizing the RF signals, producing an equalized signal;
- demodulating the equalized signal, producing demodulated data;
- producing an error signal by comparing a pilot channel of the equalized signal with a predetermined data sequence;
- and
- adapting the adaptive equalizer in response to the error signal.
Dependencies are inferred from the claim text.