Abstract: A communication system (20) includes a base station (22) and a number of peak-managed user equipment apparatuses (26) that simultaneously transmit peak-reduced FDMA communication signals (128) to the base station (22). The communication system (20) exclusively assigns payload subcarriers (44) to the apparatuses (26) and assigns a few noise-bearing subcarriers (48) for common simultaneous use by all apparatuses (26). Each user equipment apparatus (26) includes a peak reduction section (92) that distorts an otherwise undistorted modulated communication signal (86) into a distorted, peak-reduced communication signal (128) by generating and adding peak-reduction noise (131) to the undistorted signal (86). The peak-reduction noise (131) is primarily mapped onto the noise-bearing subcarriers (48) without conforming to an in-band noise constraint and may be mapped onto the assigned payload subcarriers (44) to the extent permitted by an in-band noise constraint.

Abstract: A communication system (20) includes a base station (22) and a number of peak-managed user equipment apparatuses (26) that simultaneously transmit peak-reduced FDMA communication signals (128) to the base station (22). The communication system (20) exclusively assigns payload subcarriers (44) to the apparatuses (26) and assigns a few noise-bearing subcarriers (48) for common simultaneous use by all apparatuses (26). Each user equipment apparatus (26) includes a peak reduction section (92) that distorts an otherwise undistorted modulated communication signal (86) into a distorted, peak-reduced communication signal (128) by generating and adding peak-reduction noise (131) to the undistorted signal (86). The peak-reduction noise (131) is primarily mapped onto the noise-bearing subcarriers (48) without conforming to an in-band noise constraint and may be mapped onto the assigned payload subcarriers (44) to the extent permitted by an in-band noise constraint.

Abstract: A communication system (20) includes a base station (22) and a number of peak-managed user equipment apparatuses (26) that simultaneously transmit peak-reduced FDMA communication signals (128) to the base station (22). The communication system (20) exclusively assigns payload subcarriers (44) to the apparatuses (26) and assigns a few noise-bearing subcarriers (48) for common simultaneous use by all apparatuses (26). Each user equipment apparatus (26) includes a peak reduction section (92) that distorts an otherwise undistorted modulated communication signal (86) into a distorted, peak-reduced communication signal (128) by generating and adding peak-reduction noise (131) to the undistorted signal (86). The peak-reduction noise (131) is primarily mapped onto the noise-bearing subcarriers (48) without conforming to an in-band noise constraint and may be mapped onto the assigned payload subcarriers (44) to the extent permitted by an in-band noise constraint.

Abstract: A communication system (20) includes a base station (22) and a number of peak-managed user equipment apparatuses (26) that simultaneously transmit peak-reduced FDMA communication signals (128) to the base station (22). The communication system (20) exclusively assigns payload subcarriers (44) to the apparatuses (26) and assigns a few noise-bearing subcarriers (48) for common simultaneous use by all apparatuses (26). Each user equipment apparatus (26) includes a peak reduction section (92) that distorts an otherwise undistorted modulated communication signal (86) into a distorted, peak-reduced communication signal (128) by generating and adding peak-reduction noise (131) to the undistorted signal (86). The peak-reduction noise (131) is primarily mapped onto the noise-bearing subcarriers (48) without conforming to an in-band noise constraint and may be mapped onto the assigned payload subcarriers (44) to the extent permitted by an in-band noise constraint.

Abstract: A transmitter (50) includes a low power nonlinear predistorter (58) that inserts predistortion configured to compensate for a memoryless nonlinearity (146) corresponding to gain droop and another memoryless nonlinearity (148) corresponding to a video signal. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies substantially throughout a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). A look-up table (282) has address inputs responsive to a magnitude parameter (152) of a communication signal (54). A pre-distorted communication signal (60) is responsive to the output of the look-up table, a derivative signal (204), and possibly one or more variable bias parameters (85). The look-up table (282) is updated in response to an LMS control loop.

Abstract: An RF transmitter (10) includes an RF amplifier (28) that generates an amplified RF signal (36) including a linear RF signal (92) and a spurious baseband signal (94). The spurious baseband signal (94) interacts with bias feed networks (56, 66) to cause the RF amplifier (28) to generate an unwanted RF distortion at or near the allocated RF bandwidth. A baseband compensation signal (98) is generated and equalized in an adaptive equalizer (102) then fed to the RF amplifier (28). A feedback signal (46) is obtained from the RF amplifier (28) and used to drive the adaptive equalizer (102). A feedback loop causes the adaptive equalizer to adjust a baseband signal (24, 32) supplied to the RF amplifier (28) so that the RF distortion is minimized.

Abstract: A communication system includes a transmitting unit with a peak to average power (PAPR) reduction section. The PAPR reduction section modifies the PAPR reduction it effects in a communication signal in accordance with two different error vector magnitude (EVM) constraints for each channel type, where a channel type is a distinct combination of a modulation order and a coding rate. The EVM constraint followed for each subcarrier in an OFDM or OFDMA application is selected in response to whether the subcarrier conveys voice or non-voice data. The PAPR reduction section may include a scaling filter. The scaling filter is efficiently defined through the use of a predetermined sinc function and a first stage scale factor that is calculated in response to a weighted average of excursion signal subcarrier gains, where the weighting follows the distribution of channel types through the subcarriers.

Abstract: An RF transmitter (10) includes an RF amplifier (28) that generates an amplified RF signal (36) including a linear RF signal (92) and a spurious baseband signal (94). The spurious baseband signal (94) interacts with bias feed networks (56, 66) to cause the RF amplifier (28) to generate an unwanted RF distortion at or near the allocated RF bandwidth. A baseband compensation signal (98) is generated and equalized in an adaptive equalizer (102) then fed to the RF amplifier (28). A feedback signal (46) is obtained from the RF amplifier (28) and used to drive the adaptive equalizer (102). A feedback loop causes the adaptive equalizer to adjust a baseband signal (24, 32) supplied to the RF amplifier (28) so that the RF distortion is minimized.

Abstract: A transmitter (50) includes a nonlinear predistorter (58) having two instances of an inverting transform (106, 106?) that may be implemented in a look-up table (122) and that implements a transform which is the inverse of an average terms component (96) of a nonlinear transform model (94) for an amplifier (70). The look-up table (122) may be updated using a continuous process control loop that avoids Cartesian to polar coordinate conversions. One of the two instances of the inverting transform (106) is cascaded with a non-inversing transform (108) within a residual cancellation section (110) of the predistorter (58). The non-inversing transform (108) implements a transform which is an estimate of a deviation terms component (98) of the nonlinear transform model (94). The residual cancellation section (110) produces a weak signal that replaces an unwanted residual term in an amplified communication signal (76) with a much weaker residual term.

Abstract: A transmitter (50) includes a low power nonlinear predistorter (58) that inserts predistortion configured to compensate for a memoryless nonlinearity (146) corresponding to gain droop and another memoryless nonlinearity (148) corresponding to a video signal. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies within a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). A look-up table (282) has address inputs responsive to a magnitude parameter (152) of a communication signal (54), a magnitude derivative parameter (204) of the communication signal (54), and possibly one or more variable bias parameters (85). The look-up table (282) produces a gain-correcting signal (284) that adjusts the gain applied to the communication signal (54) prior to amplification.

Abstract: An RF transmitter (10) includes an RF amplifier (28) that generates an amplified RF signal (36) including a linear RF signal (92) and a spurious baseband signal (94). The spurious baseband signal (94) interacts with bias feed networks (56, 66) to cause the RF amplifier (28) to generate an unwanted RF distortion at or near the allocated RF bandwidth. A baseband compensation signal (98) is generated and equalized in an adaptive equalizer (102) then fed to the RF amplifier (28). A feedback signal (46) is obtained from the RF amplifier (28) and used to drive the adaptive equalizer (102). A feedback loop causes the adaptive equalizer to adjust a baseband signal (24, 32) supplied to the RF amplifier (28) so that the RF distortion is minimized.

Abstract: A transmitter (50) includes a low power nonlinear predistorter (58) that inserts predistortion configured to compensate for a memoryless nonlinearity (146) corresponding to gain droop and another memoryless nonlinearity (148) corresponding to a video signal. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies substantially throughout a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). A look-up table (282) has address inputs responsive to a magnitude parameter (152) of a communication signal (54). A pre-distorted communication signal (60) is responsive to the output of the look-up table, a derivative signal (204), and possibly one or more variable bias parameters (85). The look-up table (282) is updated in response to an LMS control loop.

Abstract: A transmitter (50) includes a low power memoryless nonlinear predistorter (58) that inserts predistortion configured to address a nonlinearity (146) corresponding to gain droop and another nonlinearity (148) corresponding to deviations from an average bias condition. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies within a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). Each nonlinearity is addressed by applying gain to a communication signal (54). The amount of gain applied is determined by a look-up table (170) for one nonlinearity (146) and by a look-up table (198) in combination with a differentiator (202) for the other nonlinearity (148). The look-up tables (170, 198) are updated in accordance with modified LMS control loops.

Abstract: A transmitter (50) includes a nonlinear predistorter (58) having two instances of an inverting transform (106, 106?) that may be implemented in a look-up table (122) and that implements a transform which is the inverse of an average terms component (96) of a nonlinear transform model (94) for an amplifier (70). The look-up table (122) may be updated using a continuous process control loop that avoids Cartesian to polar coordinate conversions. One of the two instances of the inverting transform (106) is cascaded with a non-inversing transform (108) within a residual cancellation section (110) of the predistorter (58). The non-inversing transform (108) implements a transform which is an estimate of a deviation terms component (98) of the nonlinear transform model (94). The residual cancellation section (110) produces a weak signal that replaces an unwanted residual term in an amplified communication signal (76) with a much weaker residual term.

Abstract: A transmitting unit (12) clips a communication signal (14) to form a threshold-responsive signal (36, 36?) which includes in-band distortion (40) and out-of-band distortion (38). A portion of the out-of-band distortion (38) is notched within rejection bands (48, 50) adjacent to the communication signal's bandwidth (24). But remaining portions of the out-of-band distortion (38) and portions of the in-band distortion (40) are included with the communication signal (14). The remaining portion of the out-of-band distortion (38) causes the communication signal (14) to be in violation of a spectral mask (30). The mask-violating communication signal 14 with out-of-band distortion (38) and in-band distortion (40) is amplified by an RF power amplifier (22). After amplification, a bandpass filter (92) exhibiting fast rolloff regions (110) attenuates the amplified out-of-band distortion (38) causing compliance with the spectral mask (30).

Abstract: A transmitter (50) includes a low power nonlinear predistorter (58) that inserts predistortion configured to compensate for a memoryless nonlinearity (146) corresponding to gain droop and another memoryless nonlinearity (148) corresponding to a video signal. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies within a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). A look-up table (282) has address inputs responsive to a magnitude parameter (152) of a communication signal (54), a magnitude derivative parameter (204) of the communication signal (54), and possibly one or more variable bias parameters (85). The look-up table (282) produces a gain-correcting signal (284) that adjusts the gain applied to the communication signal (54) prior to amplification.

Abstract: A transmitter (50) includes a low power memoryless nonlinear predistorter (58) that inserts predistortion configured to address a nonlinearity (146) corresponding to gain droop and another nonlinearity (148) corresponding to deviations from an average bias condition. When efforts are taken to reduce memory effects, such as configuring a network of components (138) that couple to an HPA (114) to avoid resonance frequencies within a video bandwidth (140), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (58). Each nonlinearity is addressed by applying gain to a communication signal (54). The amount of gain applied is determined by a look-up table (170) for one nonlinearity (146) and by a look-up table (198) in combination with a differentiator (202) for the other nonlinearity (148). The look-up tables (170, 198) are updated in accordance with modified LMS control loops.

Abstract: A transmitter (50) includes a nonlinear predistorter (58) having two instances of an inverting transform (106, 106?) that may be implemented in a look-up table (122) and that implements a transform which is the inverse of an average terms component (96) of a nonlinear transform model (94) for an amplifier (70). The look-up table (122) may be updated using a continuous process control loop that avoids Cartesian to polar coordinate conversions. One of the two instances of the inverting transform (106) is cascaded with a non-inversing transform (108) within a residual cancellation section (110) of the predistorter (58). The non-inversing transform (108) implements a transform which is an estimate of a deviation terms component (98) of the nonlinear transform model (94). The residual cancellation section (110) produces a weak signal that replaces an unwanted residual term in an amplified communication signal (76) with a much weaker residual term.

Abstract: A transmitter (50) includes a nonlinear predistorter (58) having two instances of an inverting transform (106, 106?) that may be implemented in a look-up table (122) and that implements a transform which is the inverse of an average terms component (96) of a nonlinear transform model (94) for an amplifier (70). The look-up table (122) may be updated using a continuous process control loop that avoids Cartesian to polar coordinate conversions. One of the two instances of the inverting transform (106) is cascaded with a non-inversing transform (108) within a residual cancellation section (110) of the predistorter (58). The non-inversing transform (108) implements a transform which is an estimate of a deviation terms component (98) of the nonlinear transform model (94). The residual cancellation section (110) produces a weak signal that replaces an unwanted residual term in an amplified communication signal (76) with a much weaker residual term.

Abstract: A transmitting unit (12) clips a communication signal (14) to form a threshold-responsive signal (36, 36?) which includes in-band distortion (40) and out-of-band distortion (38). A portion of the out-of-band distortion (38) is notched within rejection bands (48, 50) adjacent to the communication signal's bandwidth (24). But remaining portions of the out-of-band distortion (38) and portions of the in-band distortion (40) are included with the communication signal (14). The remaining portion of the out-of-band distortion (38) causes the communication signal (14) to be in violation of a spectral mask (30). The mask-violating communication signal 14 with out-of-band distortion (38) and in-band distortion (40) is amplified by an RF power amplifier (22). After amplification, a bandpass filter (92) exhibiting fast rolloff regions (110) attenuates the amplified out-of-band distortion (38) causing compliance with the spectral mask (30).