Joint estimation of Carrier and Sampling Frequency Offset, phase noise, IQ Offset and MIMO channel for LTE Advanced UL MIMO

Abstract

In LTE Advanced Uplink MIMO the pilot symbols on a subcarrier and OFDM symbol are not transmitted exclusively by one layer. If the pilots are transmitted exclusively, like in LTE Advanced Downlink or Mobile WiMAX, the estimation of Carrier Frequency Offset (CFO) and Sampling Frequency Offset (SFO) can be based on correlating two pilot symbols at different OFDM symbols. In addition the estimation of CFO / SFO can be performed separately from IQ Offset and channel estimation. In LTE Advanced Uplink (UL) the pilot symbols on a subcarrier and OFDM symbol are transmitted by all layers simultaneously. As the received symbol consists of the sum of all transmitted pilot symbols, the CFO / SFO estimation approaches used for SISO seem not applicable anymore. This paper introduces a joint estimation of carrier and sampling frequency offset, phase noise, IQ offset and MIMO channel for LTE Advanced UL MIMO.