The RF Front-End (RFFE) Working Group (WG) was established as a MIPI Alliance Working Group in October 2008. The WG’s scope is to define and standardize control interface solutions for RF front-end components and modules.
The trend in mobile radio communications is towards complex multi-radio systems comprising multiple parallel transceivers. The number of radio access technologies and frequency bands to be supported is increasing, and a common control bus has become a highly-desired solution to allow for maximum flexibility and more advanced control options.
While defining and maintaining an RF front-end control interface consistent with the mission of the MIPI Alliance, the RFFE WG has worked to develop a highly efficient, flexible, and extensible interface, accommodating many variations in the overlying system design, while providing interoperability at the interface level between compliant RFICs and front-end modules.
Designed to evolve with market demands, while simultaneously remaining cost effective, RFFE enables the future of the RF front-end.
Described as the ‘backbone’ of the RF solution, the MIPI Alliance Specification for RF Front-End Control Interface (RFFE) v1.10 covers numerous front-end devices including power amplifiers, low-noise amplifiers, filters, switches, power management modules, antenna tuners and sensors. The ability to design one common control interface that can be reused for multiple modules is intended to reduce front-end complexity and speed up the time-to-market for terminals.
RFFE supports multi-mode, multi-band and multiple antennas, all in a compact two pin serial interface using a single RFFE bus designed for low gate count, low current consumption and low EMI. The specification addresses the need for targeted time-accurate control by defining channels for time-critical control, broadcast capabilities and group triggering mechanismsto facilitate synchronized events.Multiple configurations of Master and Slave are covered, ranging from one Slave on a single bus to many Slaves on a single bus or multiple buses. RFFE offers flexibility and scalability through the use of multiple receivers and transmitters simultaneously, allowing simple to complex implementations without sacrificing features.
In December 2011 the RFFE WG published a Protocol Implementation Conformance Statement (PICS) and an Application Note for the MIPI Alliance Specification for RF Front-End Control Interface v1.10. A PICS document is a vehicle common to many industry standards, providing a convenient resource for implementers to use internally to track and document which optional features are supported and that all normative requirements are met. Because the RFFE Working Group foresees that a wide community of implementers will exist for RFFE, and due to the fact that the RFFE Specification contains many optional features, it was felt that a rigorous definition of these in a logical format would provide additional benefits to implementers, as well as to those procuring devices to design and build systems.
|RF Front-End Investigation Group created||Sept. 2008|
|Charter approved by MIPI BoD||Oct. 2008|
|RFFE Working Group established||Nov. 2008|
|Basic technology selection||Dec. 2008|
|First draft Specification version||Apr. 2009|
|Technical Approval by RFFE WG||Oct. 2009|
|RFFE Specification v1.00.00 and Application Note v1.00.00||Aug. 2010|
|RFFE PICS v1.00.00||Jun. 2011|
|RFFE Specification v1.10 and Application Note v1.10||Dec. 2011|
|RFFE PICS v1.10||Dec. 2011|
|RFFE Specification v2.0||Dec. 2014|
|RFFE Application Note v2.0||Feb. 2015|
|RFFE FAQ v2.0||Feb. 2015|
Jim Ross - Skyworks Solutions, Inc.
John Oakley - Intel