Digital baseband system and process for compensating for analog radio transmitter impairments
First Claim
Patent Images
1. A digital baseband (DBB) transmitter comprising:
- (a) an analog radio transmitter;
(b) a plurality of digital compensation modules;
(c) at least one digital to analog converter (DAC) for interfacing the digital compensation modules with the analog radio transmitter; and
(d) at least one controller in communication with the analog radio transmitter and each of the digital compensation modules, wherein the digital compensation modules correct radio frequency (RF) parameter deficiencies that occur in the analog radio transmitter.
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Abstract
In order to compensate for performance degradation caused by inferior low-cost analog radio component tolerances of an analog radio, a wireless communication transmitter employs a control process to implement numerous digital signal processing (DSP) techniques to compensate for deficiencies of such analog components so that modern specifications may be relaxed. By monitoring a plurality of parameters associated with the analog radio, such as temperature, bias current or the like, enhanced phase and amplitude compensation, as well as many other radio frequency (RF) parameters may be implemented.
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Citations
43 Claims
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1. A digital baseband (DBB) transmitter comprising:
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(a) an analog radio transmitter;
(b) a plurality of digital compensation modules;
(c) at least one digital to analog converter (DAC) for interfacing the digital compensation modules with the analog radio transmitter; and
(d) at least one controller in communication with the analog radio transmitter and each of the digital compensation modules, wherein the digital compensation modules correct radio frequency (RF) parameter deficiencies that occur in the analog radio transmitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A wireless transmit/receive unit (WTRU) comprising:
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(a) an analog radio transmitter;
(b) a plurality of digital compensation modules;
(c) at least one digital to analog converter (DAC) for interfacing the digital compensation modules with the analog radio transmitter; and
(d) at least one controller in communication with the analog radio transmitter and each of the digital compensation modules, wherein the digital compensation modules correct radio frequency (RF) parameter deficiencies that occur in the analog radio transmitter. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. In a digital baseband (DBB) transmitter including a modem for generating in-phase (I) and quadrature (Q) signal components, a digital pre-distortion compensation module and an analog radio transmitter having a bias current sensor and a temperature sensor, a method of correcting radio frequency (RF) parameter deficiencies that exist in the analog radio transmitter, the method comprising:
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(a) selecting and initializing a particular communication mode;
(b) the temperature sensor monitoring the temperature of one or more components of the analog radio transmitter;
(c) the bias current sensor monitoring the bias current of one or more components of the analog radio transmitter;
(d) selecting one of a plurality of look up tables (LUTs) from a memory based on at least one of the monitored temperature and the monitored bias current; and
(e) based on information in the selected LUT, distorting the phase and amplitude of the I and Q signal components such that an RF characteristic of at least one of the components in the analog radio transmitter is improved. - View Dependent Claims (28)
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29. In a digital baseband (DBB) transmitter including a modem for generating in-phase (I) and quadrature (Q) signal components, a digital direct current (DC) offset compensation module and an analog radio transmitter, a method of correcting radio frequency (RF) parameter deficiencies that exist in the analog radio transmitter, the method comprising:
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(a) determining a first minimum detected reading associated with the Q signal component;
(b) determining a second minimum detected reading for the I signal component;
(c) determining first and second DC offset compensation values based on the first and second minimum detected readings;
(d) storing the first and second DC offset compensation values; and
(e) adjusting the DC levels of the I and Q signal components based on the stored first and second offset compensation values. - View Dependent Claims (30)
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31. In a digital baseband (DBB) transmitter including a modem for generating in-phase (I) and quadrature (Q) signal components, a digital amplitude imbalance compensation module and an analog radio transmitter, a method of correcting radio frequency (RF) parameter deficiencies that exist in the analog radio transmitter, the method comprising:
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(a) deactivating the I signal component and determining a first power level of the Q signal component;
(b) activating the I signal component and deactivating the Q signal component, and determining a second power level of the I signal component; and
(c) adjusting the power level of one of the I and Q signal components such that the first and second power levels are the same.
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32. In a digital baseband (DBB) transmitter including a modem for generating in-phase (I) and quadrature (Q) signal components, a digital phase imbalance compensation module and an analog radio transmitter, a method of correcting radio frequency (RF) parameter deficiencies that exist in the analog radio transmitter, the method comprising:
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(a) reducing the power level of each of the I and Q signal components by a predetermined amount;
(b) measuring a power level of both of the I and Q signal components at the same time;
(c) determining the phase difference between the I and Q components by comparing the power level measured in step (b) with a previously determined reference power level; and
(d) if the phase difference is not zero, adjusting the phase difference such that the I and Q signal components are orthogonal to each other. - View Dependent Claims (33)
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34. An integrated circuit (IC) for processing signals input to an analog radio transmitter, the IC comprising:
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(a) a digital pre-distortion compensation module;
(b) a plurality of digital compensation modules;
(c) at least one digital to analog converter (DAC) for interfacing the digital compensation modules with the analog radio transmitter; and
(d) at least one controller in communication with the analog radio transmitter and each of the digital compensation modules, wherein the digital compensation modules correct radio frequency (RF) parameter deficiencies that occur in the analog radio transmitter. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification