Blind selected mapping techniques for crest factor reduction of forward link CDMA signals
AssigneeGeorgia Tech Research Corporation
InventorsNing Chen, Guotong Zhou
Life of this patent
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Abstract
Disclosed are apparatus that implement blind selected mapping techniques that provide for crest factor reduction of forward link CDMA signals. Communication signals are processed using a mathematical algorithm that selectively maps a summed communication signal in a frame to another summed communication signal which has a smaller peak-to-average power ratio. The reduced dynamic range communication signal is amplified and transmitted to a receiver. At the receiver, the reduced power communication signal is processed using a mathematical algorithm that detects the selected mapping index used in the transmitter and converts the received signals into the original communication signals.
Claims28
Apparatus for reducing the peak-to-average power ratio of a forward link code division multiple access (CDMA) signal in a mobile communication system, comprising:
- a selected mapping block in a forward link CDMA transmitter for generating a plurality of equivalent representations of an original CDMA signal using a selected mapping index and for selecting an equivalent representation signal having the lowest peak-to-average power ratio for transmission for a predetermined period of time;
- and
- a demapping block in a CDMA mobile receiver for detecting the selected mapping index used in the transmitter for the predetermined period of time and for recovering current user data in the original CDMA signal.
Apparatus for reducing the peak-to-average power ratio of a forward link code division multiple access (CDMA) signal in a mobile communication system, comprising:
- a phase and PN offset selected mapping block in a forward link CDMA transmitter for generating a plurality of equivalent-representations of an original CDMA signal and for selecting an equivalent representation signal having the lowest peak-to-average power ratio for transmission for a predetermined period of time;
- and
- a phase and PN offset demapping block in a CDMA mobile receiver for detecting the phase and PN offset used in the transmitter for the predetermined period of time and for recovering current user data in the original CDMA signal.
Apparatus for reducing a peak-to-average power ratio of a code division multiple access (CDMA) signal in a mobile communication system comprising:
- a Walsh code selected mapping block in a CDMA forward link transmitter for generating a plurality of equivalent representations of an original CDMA signal and for selecting the equivalent representation signal having the lowest peak-to-average power ratio for a predetermined period of time;
- and
- a Walsh code selected demapping block in a CDMA mobile receiver for detecting the Walsh code used in the transmitter for the predetermined period of time and for recovering current user data in the original CDMA signal.
The apparatus recited in claim 27, wherein the two correlators are synchronized, each chip in a symbol is multiplied by its associated Walsh code, and all chips are summed into one symbol.
The apparatus recited in claim 27, wherein the peak detector compares the power of the two symbols output from the correlators and selects the one with the higher power for further user symbol detection.
Dependencies are inferred from the claim text.