| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 105 === LTE is a popular radio access technology (RAT) all around the world, but it
is restricted by the spectrum resource. Therefore, it needs to find more available
spectrum to transmit data. Hence, LTE in unlicensed band has been discussed
in recent years. According to 3GPP, Category 4 Listen-Before-Talk mechanism
has been decided. There are lots of works which only focus on system simulation,
but less of them concern about analytical model. In this thesis, we probe into
the measure of how to build an analytical model to evaluate the performance
of LAA . Markov model has been used widely to evaluate the performance of
WiFi system. Hence, we make use of Markov model to help us to evaluate the
performance of LAA. In addition, the proposed LAA Markov model can support
to evaluate di↵erent priority classes. Based on the evaluation result of this thesis,
in the low trac,
the di↵erence of performance between proposed LAA model and
Cisco proposed model is large. However, as the increasing load of the trac,
the
di↵erence of performance between them is getting closer. Moreover, we observe
that Cat. 4 LBT mechanism can achieve better coexistence than Cisco proposed
mechanism since Cat. 4 LBT has an additional duration which is called Initial
Clear Channel Assessment (ICCA). The final evaluation result shows a single
station with mutiple prioirty classes can avoid collisions e↵ectively since higher
priority always wins out in the competition with lower priroirty class within a
single station.
|
|---|
