AG Kommunikationstheorie


End-user Benefits of LTE Dual Connectivity in Heterogeneous Networks


In a heterogeneous network where Pico eNBs with small cell coverage are deployed within the large-scale cell coverage of Macro eNBs, the LTE Dual Connectivity (DC) feature standardized in 3GPP Release 12 can improve the user throughput by aggregating radio resources from two separate eNBs operating on different frequency layers. With DC, the serving eNB directly transmits a part of the buffered packets to the User Equipment (UE) while a second part is offloaded to a second eNB for further transmission to the UE. In this study, the end-user benefits of LTE DC are evaluated and analyzed for a realistic heterogeneous network deployment considering different traffic types and particularly typical internet traffic of today. Depending on the traffic type (e.g. for large file downloads, or webpage downloads), different gains of DC have been identified. The obtained results indicate that not only the achievable user throughput, but also the amount of data buffered in the eNBs and the latency dependency of the considered traffic determine the end-user experience. To obtain a realistic estimation of the end-user benefits, a web traffic model based on traffic measured from the current Top 25 most popular web sites has been developed and considered in the analysis. It was shown that DC is mostly beneficial when buffering in the eNBs occurs. Furthermore, for the worst users in the system, i.e. cell edge users, DC enables to significantly reduce the webpage download times especially at medium system load. Therefore, DC can be considered an interesting feature to be added to LTE networks to cope with the increasing traffic demand of the upcoming years.

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