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Implementation and evaluation of retransmissions schemes in LTE
När: Ht -10
Krav: Civ Ing, gärna kommunikationsinriktning, minst 4 i snittbetyg
Beskrivning: Se nedan
Mobile broadband for cellular networks are continuously being evolved to meet the future demands for higher data rates, improved coverage and capacity. Long Term Evolution (LTE) is currently being launched in Sweden and the rest of the world and is under constant refinement by Ericsson and others. LTE brings radio features such as advanced uplink and downlink multi antenna solutions (MIMO) and larger bandwidths from aggregating multiple carriers. These and other features will bring peak rates of 1 GB/s, but the improvements also affect other areas such as coverage, delay and flexibility.
A vital tool in reaching the high peak rates is the opportunistic use of the varying quality of the radio channel by adapting the data rate used to the instantaneous channel quality at all times. Such a scheme is bound to fail from time to time due to the stochastic nature of the problem and imperfectness in channel estimation and reporting. These failures are dealt with using a hybrid automated repeat request (HARQ) scheme, which basically detects the failures on the receiver side and - via a feedback channel - requests a retransmission of the corrupt data.
Properly designed and used, a HARQ scheme implements an efficient fine tuning of the rate adaptation, at the cost of the delays incurred by the retransmission's.
The master thesis will focus on the study of new HARQ schemes with extended feedback information, targeting a reduction the number of retransmission's needed in order to keep the incurred delays low. This is important in certain applications where the data transmission is intolerant to delays. The task includes theoretical studies, simulator implementation and evaluations. The exact scope of the thesis work will be settled later, together with the student. The work is part of a research project together with Communication Systems at Linköping University.
Master Thesis Student within Communications, at least 4 in average grades (or equivalent). Grades from relevant university education should be included in the application.
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