Main Article Content
Abstract
High data rate and high user mobility demands has driven present day wireless communications into another time, in which best in class advances are created to encourage the satisfaction of such requests, and additionally to ensure the nature of service of transmissions under unfriendly channel conditions. In past large amount of work has been made on the past years on channel estimation in OFDM systems still it is considered as area of concern in wireless communication. OFDM is currently viewed as a possible contrasting option to the customary single carrier modulation procedures for high data rate communication systems, for the most part due to its intrinsic balance effortlessness. Channel estimation can be performed for analyzing effect of channel on signal by either inserting pilot tones into all of the subcarriers of OFDM symbols with a specific period or inserting pilot tones into each OFDM symbol. Decision-directed and pilot-symbol-aided methods are two different ways for channel estimation. Pilot-symbol-aided channel estimation can be further divided in two types: block- type-pilot channel estimation and comb-type-pilot channel estimation. Different types of channel estimation technique with virtual sub carriers are discussed in this paper.