Performance Evaluation of LTE-Advanced Downlink in Inter and Intra Band Carrier Aggregation under Mobility and Interference

LTE-Advanced is a promising technology for a higher spectral efficiency and reliable transmission. This paper compares the downlink throughput experienced by mobile users in a macro-cell in an interference limited scenario with a frequency reuse of one. Bit accurate link level simulations are performed for the downlink physical shared channel (PDSCH). The study is performed for a single antenna system in specific routes at two different carrier frequencies (800 MHz and 2.6 GHz), for two urban environments in the United Kingdom, and two cell sizes. The paper also considers the carrier aggregation technique which has been proposed since it is difficult to ensure a single wide frequency band for operators. A state-of-the-art 3D ray tracer tool is used to generate 3D channel models for accurate modelling of channel statistics. The study shows that the 800 MHz band has no greater effect on the downlink throughput as compared to 2.6 GHz band, which leads to no additional advantages of inter-band aggregation (considering 800 MHz) compared to intra- band aggregation. It is also observed that a range of speeds can be handled while maintaining good performance in LTE-Advanced. We have clearly shown that the choice of cell size by mobile operators for optimum coverage depends mainly on the propagation characteristic of the environment.