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مخابرات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1396

يازده، 77ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

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محمد صادق فاضل

1396/05/15

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID11562

A New Method for Channel Estimation in MIMO Systems using Superimposed Pilot Farhad Ascarzadeh f ascarzadeh@ec iut ac ir 2017 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr F S Tabataba fstabataba@cc iut ac ir Advisor Dr M S Fazel fazel@cc iut ac ir Abstract Fading is the most important drawback for wireless systems One way to deal with the fading isto equip transmitter and receiver with more than one antenna so called MIMO In MIMO multiplecopies of data are transmitted by each antenna of the transmitter Also these systems can be used forachieving higher data rates In this case each transmitted antenna send a stream of data Based onMIMO for P2P communication massive MIMO are proposed for cellular systems In these systems base station is equipped with numerous antennas while users use devices with only one antenna Re liability high rate information exchange and simplicity in processes are advantages of these systems All of the mentioned advantages are based on the assumption that the channel state informationis availabl e at base station Therefore a method with proper accuracy for channel estimation shouldbe established One conventional way for channel estimation is using overlay conventional pilots Pilots are sequence of symbols known between transmitter user and receiver BS In channel es timation with overlay pilots all the users send time multiplexed sequence of data and pilot symbolstogether Each user must use a pilot sequence orthogonal to the other pilot sequences used by otherusers In TDD scenario for downlink due to reciprocity downlink channel can be considered asthe transpose of the uplink channel Due to the limited number of orthogonal pilot sequences someusers must use same pilot sequnces and this causes pilot contamination Pilot contamination causesa big error in channel estimation and eclipse all system operations specially in data detection andprecoding processes One suggested method for mitigating pilot contamination is using superimposed pilot for channelestimation In this method data and user specific pilot sequences transmitted together in a sameperiod of time and each transmitted symbol is the sum of the a data and a pilot symbol In thisthesis a new scheme for channel estimation and data detection based on superimposed pilot will bepresented System is assumed to be a point to point MIMO scheme Quality of channel estimationand data detection processes are evaluated using simulation results Key Words MIMO channel state information channel estimation superimposed pilot

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محمد صادق فاضل