D2D and IoT service links typically operate at lower frequencies such as L-band and S-band MSS spectrum, and sub-3GHz terrestrial cellular spectrum used for SCS. These lower frequencies provide favorable propagation characteristics for communicating with small, low-gain user devices.

Individual D2D/IoT carriers are typically only a few to tens of megahertz wide. The key RF challenge is therefore not ultra-wide instantaneous bandwidth, but the ability to support multiple frequency bands, operators, and geographic regions. As satellites move across the Earth, a highly configurable RF architecture with wide frequency coverage, fast frequency hopping and spectrum agility becomes increasingly important, with the proliferation of LEO constellations.

Direct RF-sampling architectures are an excellent choice for this requirement. Unlike traditional zero-IF architectures, direct RF sampling architecture provides flexible multi-band operation and fast frequency reconfiguration while eliminating I/Q mismatch, local-oscillator leakage and DC-offset calibration. This flexibility enables a common payload hardware platform to support different frequency bands and operating scenarios through software configuration.