Pulse shaping which compensates for component distortion
First Claim
1. A method for defining the relationship between frequency and amplitude of a pulse function modulating a data stream for transmission in a telecommunications system in accordance with a predetermined modulation scheme to compensate for distortion by a component of the transmitter, wherein the telecommunications system has desired criteria for respective associated cost parameters, and the pulse function for modulating is determined by:
- defining cost functions representing the deviation of a respective one of the cost parameters from the associated desired system criterion; and
defining the amplitude of the pulse function over a range of frequencies in dependence on the cost functions and the distortion for which compensation is to be made.
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Accused Products
Abstract
A method is provided for defining a pulse function shape for acting on a data stream for transmission in a telecommunication system which compensates for distortion by a component of the transmitter. The method comprises defining desired cost parameters (e.g., error functions for amplitude, BER, bandwidth, energy, AFC) and defining the shape of the pulse function in dependence of the desired cost parameters and the distortion to be compensated for. A pulse generator, modulator and communications device providing such a pulse function are also provided. Application in dual mode TDMA/CDMA system.
21 Citations
33 Claims
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1. A method for defining the relationship between frequency and amplitude of a pulse function modulating a data stream for transmission in a telecommunications system in accordance with a predetermined modulation scheme to compensate for distortion by a component of the transmitter, wherein the telecommunications system has desired criteria for respective associated cost parameters, and the pulse function for modulating is determined by:
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defining cost functions representing the deviation of a respective one of the cost parameters from the associated desired system criterion; and defining the amplitude of the pulse function over a range of frequencies in dependence on the cost functions and the distortion for which compensation is to be made. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A pulse function generator arranged to convert a data stream in accordance with a pulse function shaped by defining the relationship between frequency and amplitude of a pulse function which modulates the data stream for transmission in a telecommunications system for compensating for distortion by a component of a transmitter, wherein the telecommunications system has desired criteria for respective associated cost parameters, the pulse function generator comprising:
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means for defining cost functions representing the deviation of a respective one of the cost parameters from the associated desired system criterion; and means for defining the amplitude of the pulse function over a range of frequencies in dependence on the cost functions and the distortion for which compensation is to be made. - View Dependent Claims (28, 29, 30, 31)
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32. A dual mode communication device operable in a first mode in a TDMA telecommunications system in which a channel is a combination frequency and a timeslot and a second mode in a CDMA telecommunications system, comprising a modulator for modulating a data stream with a carrier signal in accordance with a predetermined modulation scheme in both the first and the second modes of operation and a pulse function generator for shaping a data stream in accordance with respective pulse functions responsive to the mode of operation of the communication device and distortion by a component of the transmitter.
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33. A dual mode communication device operable in a first mode when a first set of cost parameters are desired and in a second mode when a second set of cost parameters are desired, the dual mode communication device comprising:
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a modulator for modulating a data stream with a carrier signal in accordance with a predetermined modulation scheme in both the first and second modes of operation; a first pulse function generator for shaping a data stream in accordance with a pulse function shaped in dependence on the first set of desired cost parameters and distortion by a component of the transmitter; a second pulse function generator for shaping a data stream in accordance with a pulse function shaped in dependence on the second set of desired cost parameters and distortion by a component of the transmitter; and means for selecting one of the pulse function generators in accordance with the mode of operation of the communication device.
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Specification