Advanced RF Front-End and Transceiver Systems Design Overview for Carrier Aggregation based 4G/5G Radios
Over the past few years, there has been an explosion in the mobile data usage due to increasing number of tablets and smart phones. To support such demand, wider transmission bandwidths are needed, and hence, the technique of Carrier Aggregation (CA) has been introduced in 4G cellular systems. This enables scalable bandwidth expansion beyond the single LTE carrier by aggregating two or more LTE component carriers of similar or different baseband bandwidth, which can be chosen from the same (intra-band) or different (inter-band) 3GPP frequency bands. Furthermore, CA is supported by both FDD and TDD modes, and this offers the optimum flexibility in the way the spectrum is utilized and how the network scheduling is configured. In order to push towards 5G data rates (>1Gbps), leveraging more antennas and transmitting more bits per symbol to increase spectral efficiency requires the use of MIMO and higher-order modulation techniques. This presentation focuses on discussing the RF system architectural challenges for LTE-Advanced and sub-6GHz 5G NR based user equipment (UE) radio, and the resultant increased complexity in the radio due to the use of CA, MIMO, and higher order modulation techniques; furthermore, concurrency and coexistence scenarios with other radio access technologies (RAT) are considered in how they further add to the complexity of the RF frontend and to its linearity requirements.