To decrease the HW complexity, the signals of multiple radio bands are ideally fed through a single transceiver chain. The multiplication of transceiver chains by the number of supported bands and the increase of the number of included components are avoided, reducing size, weight and cost.
The approach is based on broadband or multi‐band capability of components used for data and frequency conversion, amplification and filtering. Newly developed radio frequency (RF) data converters facilitate the generation of signals directly at radio frequencies.
This includes the digital‐to‐analog and frequency conversion. Operating at sampling rates between 9 and 15 Gsamples/s, they show a broadband performance of up to 2 GHz signal bandwidth positioned arbitrarily at up to 6 GHz carrier frequency. The high‐speed serial data interface allows the separated transmission of signals for different radio bands enabling an efficient utilization of the interface. This advantage is supported by numerically controlled oscillators (NCO) together with up or down conversion functionalities included in broadband digital‐to‐analog converters (DAC) or analog‐to‐digital converters (ADC). In this way, data and frequency conversion are provided by a single component for multiple radio bands. The implementation of the RF signal generation with newest samples of DACs operating at 12 Gsamples/s, (e.g., those available at [4],[5]), targets three‐band operation at carrier frequencies around 2.6, 2.8, and 3.5 GHz, as shown in below Figure .
The Reference :
5G System Design
Architectural and Functional Considerations and Long Term Research
