Influence of the EER / polar transmitter architecture on IQ impairments for an OFDM signal

This paper presents the study and simulation of IQ impairments influence in a Radio Frequency (RF) transmitter architecture. The context is the transmission of OFDM signals such as IEEE 802.11a. The transmitter architecture is considered in two cases : a classical reference case such as homodyne for example and a linearised case, based on the EER (Envelope Elimination and Restoration) or polar architecture. EER was considered here because it provides an interesting high efficiency multi-standard transmitter architecture solution for actual digital communications high data rate standards. Equations are derived in the case of emission and reception of an OFDM signal with N sub-carriers and simulations are performed to confirm the theoretical results. Conclusions are given concerning the impact of IQ impairments on the Error Vector Magnitude (EVM) for both architecture cases.