Phase noise mitigation for millimeter-wave SC-FDE MIMO systems

Because the frequency of millimeter-wave transmissions is extremely high, phase noise (PN) caused by imperfect oscillators greatly degrades transmission performances. Traditionally, for single carrier frequency domain equalization (SC-FDE) with single input and single output (SISO) systems, unique word (UW) structure is widely used as CP as well as training sequences to compensate for PN. However, UW is hardly compatible with SC-FDE MIMO (multiple input and multiple output) systems supported by the classical CSD (cyclic shift diversity) operation. This paper proposes a new block structure that fits for SC-FDE MIMO systems with CSD operation. Meanwhile, a decision-directed algorithm that can cope with PN is also proposed. Decision-directed phase noise compensation (DD-PNC) estimates the PN at each sampling time by using the one-tap least mean square (LMS) algorithm which utilizes the outputs of the decision as a reference signal and DD-PNC compensates time-domain received signals for PN by using the estimates. Simulation results indicate that the proposed new block structure and receiver architecture provide great transmission performances, and 4dB gain is achieved when employing high-order modulation 64QAM.