Research On Constellation Design Based Phase Noise Suppression Algorithm

With the growing demand of wireless communication, frequency resource becomesincreasingly shortage. How to transmit large quantities of data in the limited bandwidthwith high rate is a problem to be solved. One effective way is to improve themodulation order, that is to say, mapping more bits into one symbol. Under the averagepower constraints, the high-order traditional constellation QAM becomes denser in thesignal plane. Then phase noise generated by equipments which deal with frequencymakes the constellation points deflect. As a result, the error rate of system rises. Thispaper gives an intensive study researches on phase noise suppression by constellationdesign, and combination with soft information is also studied.Firstly, the paper introduces the definition of phase noise and some commonstatistical models in detail. What’s more, it analyses the fatal flaw of the traditionalsquare QAM modulation which is susceptible to the influence of phase noise. That’s thereason why it is necessary to design new robust constellation structure. Then, we paymore attention to a variety of anti-phase noise constellation structure and designalgorithms, and their advantages and disadvantages are compared and analyzed. Finally,the paper designs a new bit mapping rule Gray code-like for the new APSKconstellation which performs best. It is proved that this mapping rule has lowcomplexity and guarantees the neighboring symbols differ by one or two bits. Based onthe above, the performance of phase noise suppression can be further improved bycombining this new constellation APSK and LDPC channel coding.The simulation results show that new constellation has far more robustness tophase noise than the traditional square constellation. The proposed bit mapping ruleGray code-like for the new APSK constellation is just simple and effective. What’more,it is proved that the combination of APSK constellation and LDCP channel coding is arecommendable method to achieve good performance of phase noise suppression.