The newest iteration of the widely deployed MIPI RF Front End Control Interface, MIPI RFFE v3.0, delivers the fundamental orchestration within and across wireless devices on which the next wave of 5G rollout around the world is being based.
Deployed in almost every device with cellular connectivity manufactured in the last 10 years, MIPI RFFE has established itself as the world’s de facto standard for control of the radio frequency front end. The compact, cost-efficient and flexible two-wire control bus interface is found in handsets, smartwatches, automobiles, and a variety of other devices that leverage wireless connectivity. Across all sorts of RF systems, MIPI RFFE delivers control for the antenna tuners, filters, low-noise amplifiers (LNAs), power amplifiers, switches, and other RF components from the modem baseband and/or RF integrated circuit (RFIC) transceiver.
The newest version of the interface, version 3.0, was released in May 2020. With this version, MIPI RFFE was optimized and streamlined specifically to help system architects, original equipment manufacturers (OEMs) and device vendors advance 5G rollout in the Frequency Range 1 (FR1) of traditional sub-6 GHz cellular bands. And because the latest version of MIPI RFFE is backward compatible with earlier versions of the specification, OEMs and device vendors need not overhaul the interface’s physical layer to migrate systems for today’s 5G business opportunities.
The RF front end is a potentially chaotic environment in 5G, with significantly more wireless components to be linked and synchronized than ever before. MIPI RFFE, though, brings order to it, enabling quicker and more efficient configuration changes within and across RF subsystems by applying common control mechanisms to up to 15 devices from up to four master devices per bus instance.
Enhanced and expanded “trigger” functionality is the key to MIPI RFFE v3.0’s better timing precision required for 5G use cases. In specifying a more robust suite of complementary trigger features for synchronizing and scheduling register-setting changes, the MIPI RF Front-End Control Working Group adapted the interface for the 3GPP 5G standard’s smaller reconfiguration windows and requirements for lower-latency switching among various bands and band combinations. The interface’s “timed triggers,” “mappable triggers” and “extended triggers” function in combination with one another to enhance throughput efficiency, shave packet latency and improve timing precision. MIPI RFFE v3.0 delivers a 20x boost in timing precision for back-to-back triggering operations, for example.
What might the next iteration of MIPI RFFE bring? Already, the MIPI RF Front-End Control Working Group is considering potential next frontiers for the specification—Massive MIMO (multiple input, multiple output), the Frequency Range 2 (FR2) of cellular bands (24.25 GHz to 56 GHz) and even possible 6G network evolution.
Now, in fact, is a great time to provide input on the next-generation requirements for the interface. Please join the MIPI RF Front-End Control Working Group to learn more and contribute your perspectives and ideas.