Phase Noise Effects And Suppression Algorithm For 60GHZ Systems

60GHz band communication has proved to be a phenomenal success worldwide for its incomparable advantages as the wireless communication technology develops. However, it can suffer more significant performance degradation due to the presence of RF impairment compared with the systems operating at lower carrier frequencies. Such challenges need to be overcome before full potential of 60GHz band can be utilized.Characteristics of high frequency around 60GHz make it a challenging task for accurate and efficient RF components design, hence, an effective baseband RJF impairment estimation and suppression technique is of great importance in order to ensure reliable transmission. In this dissertation, one of the significant RF impairment, phase noise (PN) is investigated on SC-FDE based 60GHz systems, and an improved K-L expansion based method using orthogonal basis from the autocorrelation matrix of PN is introduced to deal with the PN reconstruction. In addition, the link budget and capacity analysis of the system is also obtained using the channel model and frame format provided by the IEEE 802.1 lad, which proved that the influence of RF impairment after compensation do little harm to the performance of the SC-FDE system. The rest of the dissertation is organized as follows:First, an overview of 60GHz band and RF nonlinear influence on communication is outlined, the system modulation and channel model according to IEEE 802.11 ad standards is also given for the need of further research.Secondly, the link budget and system capacity is analyzed with simple RF impairment mitigation. In this part, the model of power amplifier, phase noise and IQ imbalance is presented and some simulation results are given to illustrate the RF effects.Finally and the most importantly, the PN effects and suppression algorithm is explored:Phase noise is one of the most challenging problems in SC-FDE 60GHz systems, it is produced by the local oscillators in transceivers and can be much higher than that of lower frequency, which may cause substantial degradation in receiver performance. According to some conventional scheme, the common phase error (CPE) compensation method worked well only in small constellation and low PN level. When it comes to high level PN especially under higher order modulation formats such as 16-QAM and 64-QAM the suppression performance is limited. In order to alleviate this problem, the receiver employing K-L expansion based method is proposed to enhance the performance. The autocorrelation matrix of the PN is derived to obtain several primary orthogonal basis for PN reconstruction, an estimate of a few of the basis coefficients is then computed from the received signal using the least square (LS) method. Algorithm analysis and simulation results are presented at last to show the effectiveness of the scheme. It shows that our scheme can effectively remove the phase noise with 5 or 6 iterations under high level PN and multi-QAM modulation format compared with the existing methods.