Kanavien yhdistämistekniikan suorituskyvyn arviointi edistyneissä LTE-järjestelmissä
Reinikainen, Antti · Aaltodoc (Aalto University) · 2015
Carrier Aggregation (CA) is an essential technology component in LTE-Advanced (LTE-A). CA is capable of combining up to five Long Term Evolution (LTE) carriers to be used for multicarrier transmission in both downlink and uplink. CA provides increased throughputs, additional capacity and possibilities for load balancing. This thesis presents the key features of CA. Furthermore, the results from CA performance measurements are analyzed and presented. The measurements were conducted in live network to evaluate the end-user experience. The objective was to determine whether CA is capable of delivering the performance that could be theoretically expected. The performance was measured in LTE-A radio network using 2x20 MHz bandwidth with 2x2 MIMO configuration and Category 6 User Equipment (UE). Only downlink CA was measured, since uplink CA capable UEs were not commercially available. The performance was evaluated with stationary and mobility measurements. The results indicate that CA is capable of providing the expected performance gain. In good radio conditions the maximum downlink throughput is close to the 300 Mbit/s. Furthermore, CA performs well in poor radio conditions. The performance gain can be more than 100 %, if the additional carrier is on an unused band. In CA, a secondary component carrier is configured for the UE, in addition to the primary carrier. The operation is performed in connected state either after connection setup or radio handover. The delay in secondary carrier addition was measured to evaluate the impact on user experience. The results indicate that the secondary carrier addition after connection setup or handover is sufficiently fast, and do not have an impact to the user experience.