Bandwidth dependency channel model: On the impact to carrier aggregated systems

One of the key technologies introduced in LTE-Advanced in order to increase the capacity is carrier aggregation (CA). Based on this scheme, continuous and non-continuous sub-bands are aggregated in order to achieve larger bandwidth. Such a new technique introduces various challenges in both system aspect and the modeling of the wireless channel. In particular, the traditional channel models that was proposed for current LTE networks may not be appropriate for the LTE-Advanced systems that adopt CA scheme. This is mainly due to the fact that small-scale variations of the channel may change depending on the channel bandwidth. In this paper, we studied and analyzed the bandwidth dependency of the wireless channel based on indoor channel measurements performed at Stanford University. The measurement were conducted at 2.45 GHz center frequency and covered a bandwidth of up to 70 MHz. Here, both large-scale and small-scale channel properties are investigated. In particular, the bandwidth-dependent fading parameters such as K-factor, fade depth, number of paths and delay spread are extracted for both fixed and nomadic receivers. Based on this, we proposed interpolated models for these fading parameters, which can be used to improve the accuracy of simulation for carrier aggregated systems.