Hello Ranjeet,
There are numerous ways to do it. You can vary different parameters of your design. As alistu said , if possible upload the .osd file of your simulation and we may help accordingly.
For now one thing you can do to increase the Quality factor is increasing the symbol rate in the layout parameter tab or increase the power for transmission if permitted to do so. These are basic tricks to increase quality factor however it would be appropriate if you upload your osd file.
regards