Title :
Reducing the crest factor of a CDMA downlink signal by adding unused channelization codes
Author :
Väänänen, Olli ; Vankka, Jouko ; Viero, Timo ; Halonen, Kari
Author_Institution :
Electron. Circuit Design Lab., Helsinki Univ. of Technol., Finland
Abstract :
In a CDMA system the downlink signal typically has a high peak-to-average ratio (crest factor). This sets strict requirements for the linearity of the power amplifier, which leads to poor efficiency and high costs. This letter discusses a method for reducing the crest factor based on the addition of a signal which is orthogonal to all the active channel codes. Therefore, in an ideal case, no error is introduced at the receiver.
Keywords :
channel coding; code division multiple access; CDMA; clipping method; crest factor reduction; downlink signal; high peak-to-average ratio; orthogonal codes; power amplifier linearity; unused channel codes; Baseband; Costs; Downlink; Energy consumption; High power amplifiers; Linearity; Multiaccess communication; OFDM; Peak to average power ratio; Signal generators;
Journal_Title :
Communications Letters, IEEE
DOI :
10.1109/LCOMM.2002.804245
