| Summary: | 碩士 === 國立交通大學 === 電信工程研究所 === 98 === Due to the continuously increasing number of mobile multimedia uses, packet switch streaming would make much downlink resource be occupied. In order to make downlink resource be taken advantage more efficiently, multimedia broadcasting/multicasting service (MBMS) is proposed. In LTE, single frequency network can be further utilized to reinforce the coverage and the power of transmitting signal of MBMS.
However, retransmission technique which is usually used to increase data robustness is hard to realize in broadcasting/multicasting. If unicast retransmission technique works in broadcasting/multicasting, it would result in the waste of downlink resource. In this thesis, we propose the retransmission scheme which takes advantage of feedback channel and grouping of mobile users to strike a balance between data block error rate and retransmission rate. Additionally, we propose two kinds of feedback channel assignment to pursue more flexible assignment. We have two ways to let base station judge whether the retransmission will be performed or not. First one is based on threshold, and the second one is based on probability. In simulation, the proposed scheme indeed decreases retransmission rate with acceptable data block error rate. Besides, goodput of proposed is larger than the compared schemes.
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