Abstract-As the internet is becoming rich with huge information, retrieving the wanted information is a huge challenge. Due to huge variation in framing a query by the individuals, matching of the terms with the document to be searched are facing many challenges. Researchers have worked on problem of identifying the correct essence of the user query by adding additional useful terms. They are currently working on this kind of Query Expansion (QE
I. INTRODUCTIONIn our day to day life, fetching significant amount of data for academic, administrative and commercial purposes have increased. Therefore the need of the query is required to get some information for solving problems from which user can reach a certain conclusion. The role of the query is same like asking the question to search engine like google, yahoo, bing, etc. The query can be related to government, academic, commercial or personal from which doubts can be get cleared or suggestions with deep knowledge can be gained. In short, the query is something which comes in human mind. The search engine is designed to search for information where search results are the number of pages consisting of different forms of files. Among these pages, the aim is to get query related documents only.Information Retrieval [1] as IR is an activity of finding useful matter of an unstructured nature usually text within the large collection of documents stored on the computer which satisfies users need. The aim is to achieve query related documents only. Unstructured data is not organized in a pre-defined manner. The query given by a user to information retrieval can be ambiguous which may result in unrelated or irrelevant documents. The query given by user can be ambiguous due to various reasons like User lack of knowledge, Word with more than one sense, forming query in an inappropriate way, Vocabulary Mismatch problem(VMP) [2]. It is faced while matching a query with documents which is the central problem in IR which occurs when the term of the query doesn't match with the terms in relevant documents.Information storage and retrieval is a systematic storage of data collection which should be displayed on request. Relevance is a fundamental concept in Information Retrieval. Relevance is something which is related to the user query. There are many factors that go into an individual's selection as to whether a particular document is relevant or nonrelevant. It sounds simple but just by comparing and matching the keywords of a query with documents is not sufficient in terms of relevance and yields poor results. Thus considering all these factors one may design an algorithm to achieve more suitable results for the requested query.Section II describes the research work in the area of Query Expansion (QE). Different techniques are discussed in section III. An endeavour to compare different techniques briefly in section IV. A proposed method in section V. Section VI concludes the survey of different methods.