PAPR Analysis of a Multiplex of Modulated Carriers in a Software Radio Context

摘要

One of the disadvantages of multicarrier signals is unquestionably their high crest factor level. The more this dynamic is raised, the more the non-linearity effects brought about by the transmission chain (in particular by the power amplifiers) are stringent. Before studying techniques to decrease the effects of non-linearities, it is worthwhile and necessary to clarify the Peak to Average Power Ratio (PAPR) notion. An initial definition was given for the Orthogonal Frequency Division Multiplexing (OFDM). However, we consider that this definition is not satisfactory since it does not give a realistic vision of the true PAPR, mainly because the time duration of the PAPR computation is not long enough. It is expected that in Software Radio (SWR) the amplification of a whole frequency band will be required. Obviously, the PAPR of a large frequency band will reach great values. Therefore in SWR context we will again meet the amplification of signals with high PAPR problem. Consequently, it is very important to characterize this parameter in order to qualify the performances of all new techniques studied in the software radio context. In this paper, we analyze this parameter in the new context of the software radio, starting from the classical PAPR OFDM definition.