Performance Analyses of Different MIMO Modes In LTE Release 8 Networks
Brutyan, Artur (2013)
2013
Master's Degree Programme in Information Technology
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2013-05-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201305221144
https://urn.fi/URN:NBN:fi:tty-201305221144
Tiivistelmä
The multi-antenna techniques are the one of the key features in 3GPP LTE specifications. Thus, the understanding of different transmission modes behaviour, available in LTE, is very important for high quality and cost efficient LTE network deployment. Besides, the lack of available practical studies of this topic makes the problem even more attractive.
This master thesis work is focused on measurement based performance analyses of different special multiplexing (SM) modes available in LTE Release 8 networks using the same LTE base stations as used in this study. Field measurements have been carried out in different propagation environments. In analyses, user application throughput and MIMO utilization have been studied to demonstrate the efficiency of each mode.
The measurement results are different than the theoretical and simulation based studies. The results clearly show that the open-loop-dynamic SM is the best choice, independent of the environment, for SNR > -2 to -5 dB and can provide up to 3 Mbps or 11.7% advantage over closed loop SM. The open loop static SM is as good as open loop dynamic SM only for very good, SNR > 10 to 15 dB, channel conditions. And, for the bad channel conditions, SNR < -2 to -5 dB, the behaviour of all modes is the same that is transmit diversity and SM provide similar throughputs. The SNR threshold for MIMO utilization is found to be approximately -2 to -5 dB. And, another interesting conclusion is that no transmission percentage is going up from 5% up to 20% for SNR > 15 dB, which means, that there is a significant interference between parallel data streams. The bad performance of the closed loop is associated with low CQI reports for codeword 1 as the UE reduces the SNR for codeword 1 to mitigate the interference between parallel data streams.
The results can be generalized only for the studied equipment hardware, software and parameters as the other vendors can have slightly different implementation of some parts of LTE. But any way, the results show that knowledge of the different SM modes behaviour can help to increase the quality of the network.
This master thesis work is focused on measurement based performance analyses of different special multiplexing (SM) modes available in LTE Release 8 networks using the same LTE base stations as used in this study. Field measurements have been carried out in different propagation environments. In analyses, user application throughput and MIMO utilization have been studied to demonstrate the efficiency of each mode.
The measurement results are different than the theoretical and simulation based studies. The results clearly show that the open-loop-dynamic SM is the best choice, independent of the environment, for SNR > -2 to -5 dB and can provide up to 3 Mbps or 11.7% advantage over closed loop SM. The open loop static SM is as good as open loop dynamic SM only for very good, SNR > 10 to 15 dB, channel conditions. And, for the bad channel conditions, SNR < -2 to -5 dB, the behaviour of all modes is the same that is transmit diversity and SM provide similar throughputs. The SNR threshold for MIMO utilization is found to be approximately -2 to -5 dB. And, another interesting conclusion is that no transmission percentage is going up from 5% up to 20% for SNR > 15 dB, which means, that there is a significant interference between parallel data streams. The bad performance of the closed loop is associated with low CQI reports for codeword 1 as the UE reduces the SNR for codeword 1 to mitigate the interference between parallel data streams.
The results can be generalized only for the studied equipment hardware, software and parameters as the other vendors can have slightly different implementation of some parts of LTE. But any way, the results show that knowledge of the different SM modes behaviour can help to increase the quality of the network.