I am a second year master student and I am preparing the proposal for my upcoming master thesis in the spring semester. My topic is the perception of immigrant about the integration process and challenges they face in their path to integration in Sweden. I planning to conduct a qualitative research design, particularly I want to undertake a case study. I know the fact that, in qualitative research, including theoretical background in your proposal is very challenging before you collect your data. However I am instructed to do so. So please can any one help me to find out theories related to integration of immigrant to mainstream society. I was thinking that I can use assimilation and multiculturalism as my theories but I am not sure whether they are concepts or theories. I am also thinking if I can use Acculturation model as theoretical background. Please let me hear form your side. thanks