7.3 A 40nm low-power transceiver for LTE-A Carrier Aggregation

Abstract

The demand of higher data-rates for mobile communication has driven the LTE standard to adopt methods to increase channel bandwidth by Carrier Aggregation (CA), this is known as LTE-Advanced (LTE-A). Due to regional spectrum allocation, these carriers can be inter-band, or intra-band with contiguous (CCA) or non-contiguous (NCCA) channels. The band combinations create a major challenge for an LTE-A transceiver (TRX) in dealing with the intermodulation (IM) of aggregated channels. These IM sources include fundamental and harmonics of LOs, VCOs, and the transmitter (TX) modulated signals. In addition, when multiple receivers (RXs) and synthesizers (SXs) are needed to support CA, power consumption becomes a key challenge. This work describes an adaptive RX that can adjust trade-offs between power consumption and RX performance, allowing significant power reduction under normal field conditions. Additionally several techniques are described for mitigation of CA IM spurs.