The Linearity-Efficiency Compromise

The demand on telecom operators for new services and increased data rates has created difficult requirements for the signal-to-noise-and-distortion ratio of wireless systems. Furthermore, wireless spectrum has become a scarce and expensive commodity, which has led to the elimination of guard bands in the spectrum allocation. Nonlinear distortion generates both in-band and side-band distortion, which degrades the signal-to-distortion ratio of the channel and its adjacent channels. This results in the expectation of high levels of linearity from wireless circuits. On the other hand, transceiver portability, infrastructure operating costs, and global environmental issues impose a need for power management awareness for a more efficient use of supplied power.