US 2004/0062327 A1 · Multipath rake receiver of high symbol rate burst communication system

Abstract

A multipath RAKE receiver, for combining various significant component signals of a multipath fading signal and correcting the frequency error and the phase error associated with each significant component signal, consists of a multipath splitter, a plurality of delay devices, a plurality of complex multipliers, a plurality of path strength estimators, a plurality of error signal generators, a plurality of complex scaling signal updating devices, an adder, a decision circuit, and a controller. First, the controller extracts information about each significant component signal and generates initial complex scaling signals and other control and timing signals. Under the control of the controller, each delay device delays a corresponding significant component signal for a different amount of time so that all the delayed significant component signals can be aligned up. Multiplying one of the delayed significant signals by a corresponding complex scaling signal from one of the complex scaling signal updating devices, each complex multiplier puts a proper weight on a corresponding component signal and corrects both frequency error and phase error associated with this component signal. By adding the signals from all the complex multipliers together, the adder generates a summation signal. With the summation signal, the decision circuit makes a decision on the transmitted symbol. Comparing the signal from the decision circuit with a corresponding significant component signal, each error signal generator produces an error signal for the component signal. By monitoring a corresponding significant component signal, a path strength estimator generates a corresponding path strength signal. Finally, receiving all the error signals and all the path strength signals, the complex scaling signal updating devices generate updated complex scaling signals.

Claims20

Dependent claims

A system for combining pluralities of significant component signals of a multipath fading signal and correcting both frequency error and phase error associated with each of said pluralities of significant component signals, comprising:

a multipath splitter, for separating said multipath fading signal into said pluralities of significant component signals;
pluralities of delay devices, coupled to said multipath splitter and having pluralities of outputs, for delaying each of said pluralities of significant component signals for a respective amount of time to produce pluralities of delayed significant component signals;
pluralities of complex multipliers, coupled to said pluralities of delay devices respectively and to pluralities of complex scaling signal updating devices respectively, for multiplying each of said pluralities of delayed significant component signals by a respective complex scaling signal to produce pluralities of scaled significant component signals;
an adder, coupled to said pluralities of complex multipliers, for adding said pluralities of scaled significant component signals together to produce a summation signal;
a decision circuit, coupled to said adder, for making a decision on the transmitted symbol from said summation signal;
pluralities of path strength estimators, coupled to said pluralities of delay devices, for estimating the signal strength of each of said pluralities of delayed significant component signals to produce pluralities of path strength signals;
pluralities of error signal generators, coupled to said pluralities of complex multipliers and said decision circuit, for generating the error signal between the output signal of said decision circuit and each of said pluralities of scaled significant component signals to produce pluralities of error signals;
a controller, coupled to relevant devices, responsive to detecting preamble symbols and generating pluralities of initial complex scaling signals, for generating control and timing signals;
and
said pluralities of complex scaling signal updating devices, each coupled to receive a respective initial complex scaling signal from said controller, a respective path strength signal from one of said pluralities of path strength estimators, and a respective error signal from one of said pluralities of error signal generators, for updating each of said pluralities of complex scaling signals to produce pluralities of updated complex scaling signals.

7 more elements

A system for generating a complex scaling signal for a significant component signal of a multipath fading signal, receiving pluralities of control signals, an initial complex scaling signal, a complex error signal, and a path strength signal, said system comprising:

first multiplexing means, coupled to receive said initial complex scaling signal and a second modified complex scaling signal from magnitude adjusting means, under the control of a control signal of said pluralities of control signals, for selecting one of its two complex input signals as its complex output signal;
first register means, coupled to said first multiplexing means, for saving the complex output signal of said first multiplexing means to produce said complex scaling signal;
phase adjusting means, coupled to receive said complex scaling signal from said first register means and said complex error signal, for adjusting the phase of said complex scaling signal to produce a first modified complex scaling signal;
scaling strength means, coupled to said phase adjusting means, for estimating the signal strength of said first modified complex scaling signal to produce a scaling strength signal;
and
said magnitude adjusting means, coupled to receive said scaling strength signal from said scaling strength means, said first modified complex scaling signal from said phase adjusting means, and said path strength signal, for adjusting the magnitude of said first modified complex scaling signal to produce said second complex scaling signal.

3 more elements

A method of combining pluralities of significant component signals of a multipath fading signal together and correcting both frequency error and phase error associated with each of said pluralities of significant component signals, comprising:

generating an initial complex scaling signal for each of said pluralities of significant component signals to produce pluralities of initial complex scaling signals;
taking each of said pluralities of initial complex scaling signals as each of pluralities of complex scaling signals respectively;
delaying each of said pluralities of significant component signals by a different amount of time to produce pluralities of delayed significant component signals;
multiplying each of said pluralities of delayed significant component signals by each of said pluralities of complex scaling signal respectively to produce pluralities of product signals;
adding said pluralities of product signals together to produce a summation signal;
making decisions on the transmitted symbols from said summation signal;
estimating the path strength for each of said pluralities of delayed significant component signals to produce pluralities of path strength signals;
estimating the error signal for each of said pluralities of product signals to produce pluralities of error signals;
and
adjusting the phase and magnitude of each of said pluralities of complex scaling signals to produce pluralities of updated complex scaling signals.

7 more elements

Dependencies are inferred from the claim text.

Multipath rake receiver of high symbol rate burst communication system

Life of this patent

Multipath rake receiver of high symbol rate burst communication system

Life of this patent

Abstract

Claims20