Stochastic geometric performance analysis for Carrier Aggregation in LTE-A systems

Carrier Aggregation is considered as a key revolution in Long Term Evolution-Advanced systems to meet the explosively increasing aspiration for high data rates. Unlike extensive simulative evaluations on CA in literature, current theoretical analysis on CA is not convincing due to lack of effective interference modeling. In this paper, we exploit the theory of stochastic geometry to provide tractable statistical interference modeling for downlink CA in LTE-A systems. Our objective is to demonstrate the benefits of CA by comparing the user performance between the legacy LTE users and LTE-A users. Specifically, we first model the distributions of base stations and users into Poisson Point Processes. Then, the user service probability and subchannel usage in each carrier are calculated for LTE and LTE-A users, respectively. The obtained probabilities are applied to derive the user SINR distribution and ergodic rates. To better clarify the impact of system/user parameters on the investigated performance, a special case is presented where the network is interference-limited and the channel fast fading is considered as Rayleigh fading. Finally, simulation results validate our analytical model and demonstrate that LTE-A users can achieve significantly better SINR and ergodic-rate performance than LTE users when the cell is not heavily loaded.