ADAPTIVE PREDISTORTION FOR A TRANSMIT SYSTEM

• US 20100214018A1
• Filed: 04/27/2010
• Published: 08/26/2010
• Est. Priority Date: 07/03/2003
• Status: Active Grant

• Current Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Original Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Inventors: Saèd, Aryan
• Granted Patent: US 8,248,160 B2
• Time in Patent Office: Days
• US Class Current: 330/149
• CPC Class Codes: H03F 1/0294 using vector summing of two or more constant amplitude phase-modulated signals
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 1/3282 Acting on the phase and the amplitude of the input signal
• CPC Class Codes: H03F 2201/3233 Adaptive predistortion using lookup table, e.g. memory, RAM, ROM, LUT, to generate the predistortion
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence

Abstract

Systems, methods, and devices relating to the provision of deliberate predistortion to an input signal to compensate for distortions introduced by an amplifier subsystem. An input signal is received by a signal processing system which includes a predistortion subsystem. The input signal is decomposed and the fragments are then predistorted by the predistortion subsystem by applying a deliberate predistortion to the fragments. The predistorted fragments are then separately processed and recombined to arrive at the system output signal. The predistortion subsystem adaptively adjusts based on characteristics of the system output signal. Also, the predistortion subsystem is equipped with a control system that is state based—the state of the predistortion subsystem is dependent upon the prevailing conditions and, when required, the control system switches the state of the predistortion subsystem. A feedback signal, a replica of the system output signal, is used in updating lookup table entries used to determine the predistortion.

Claims

1. A method for controlling a predistortion subsystem for a transmission system, comprising:

processing a status of the predistortion subsystem;

storing settings for a control device configured to control the predistortion subsystem; and

transitioning the control device from one operating state to another operating state of a plurality of operating states based at least in part on the storing the settings and the processing the status.

2. The method of claim 1 comprising:

controlling an update duty cycle for the predistortion subsystem; and

updating at least on internal lookup table according to the update duty cycle.

3. The method of claim 1 comprising:

controlling an initialization duty cycle for the predistortion subsystem; and

initializing the predistortion subsystem according to the initialization duty cycle.

4. The method of claim 3 where controlling the initialization duty cycle occurs responsive to updating at least one internal lookup table of the predistortion subsystem.

5. The method of claim 1 where transitioning the control device from one operating state to another operating state includes monitoring a level of distortion of the predistortion subsystem.