OFDM PAPR reduction using cancelation vectors

摘要

A Symbol vector for RF transmission after multiplexing onto a subset of a set of subcarriers using OFDM is transformed to the time domain. A first time domain cancellation vector is generated from a basis vector that has the same dimensionality as the symbol vector. In the frequency domain the basis vector has a substantially zero value in each of a first subset of sub-carriers of the symbol vector and in the time domain the difference between a first element of the basis vector having the highest value and a second element of the basis vector having the next highest value is maximized. The first cancellation vector is subtracted from the symbol vector to produce modified symbol vector having reduced Peak-to-Average Power Ratio (PAPR). A second cancellation vector is generated using the modified symbol vector and is used to produce a second modified symbol vector having reduced PAPR.

主权项

1. A method for improving noise performance in a Radio Frequency (RF) transmitter that makes use of Orthogonal Frequency Division Multiplexing (OFDM), the method comprising:
receiving a stream of digital data symbols in the form of a plurality of symbol vectors, for RF transmission after multiplexing onto a first subset of a set of sub-carriers according to OFDM; transforming each symbol vector from the plurality of symbol vectors to the time domain; and for each symbol vector from the plurality of symbol vectors:
generating a first time domain cancelation vector from a basis vector that has the same dimensionality as the symbol vector, wherein in the frequency domain the basis vector has substantially zero value in each of the first subset of the set of sub-carriers and wherein in the time domain the difference between a first element of the basis vector having the highest value and a second element of the basis vector having the next highest value is maximized using an iterative process that is performed for a specified number of iterations or until the difference between the first element of the basis vector having the highest value and the second element of the basis vector having the next highest value cannot be further improved,generating a first modified symbol vector having reduced Peak-to-Average Power Ratio (PAPR) by subtracting the first time domain cancelation vector from the symbol vector,generating a second time domain cancelation vector using the first modified symbol vector, andgenerating a second modified symbol vector having a reduced PAPR by subtracting the second time domain cancelation vector from the first modified symbol vector.