Quick Facts

Physical Layer

CMOS Single-Ended I/Os (1.2V and 1.8V)

Fundamental features
  • High performance (up to 52 MHz bus speed)
  • Low power
  • Low EMI
  • Point to multi-point
Use Cases
  • 5G/LTE-A
  • MIMO
  • Carrier aggregation uplink/downlink
  • WiFi/Bluetooth

Industries

Icon of WiFi signal strengthIcon of a Smart PhoneIcon of a TabletIcon of a laptopIcon of an AutomobileIcon of a cloud with the letters IoT inside.Icon of 5G signal strength

Overview

A control interface that simplifies integration of complex RF front-end devices

Originally released in July 2010 as v1.00.00, the MIPI RF Front-End Control Interface, MIPI RFFESM, is a dedicated control interface for the RF front-end subsystem. It enhances the control of the complex RF subsystem environment, which has rigorous performance requirements and can include 10 to 20 components such as power amplifiers, antenna tuners, filters and switches. The interface can be applied to the full range of RF front-end components to simplify product design, configuration and integration, and to facilitate interoperability of components supplied by different vendors. The conveniences make it easier for manufacturers to address end-user needs for faster data speeds and better call quality, develop scalable solutions, and expedite time to market for new designs in the mobile, automotive and Internet of Things (IoT) sectors.

New features in the current release, MIPI RFFE v2.1, address ongoing changes in mobile technology and anticipate how system designers' needs will evolve with the commercialization of 5G. For example, the new Master Context Transfer (MCT) RFFE command sequence, where one of the masters on a multi-master RFFE bus shuttles larger amounts of information from one master to another, enables quick hops between radio technologies that can be controlled via different radio chains. The multi-master feature was introduced in RFFE v2.0, but the addition of MCT command sequences in RFFE v2.1 provides more efficient master-to-master transfer when larger amounts of data are involved.

MIPI RFFE v2.1 also extends the number of triggers, which are used to synchronize changes in register settings within a slave device, and potentially across multiple devices, from 3 to 11. Another added capability, Masked Write command sequence, enables a transceiver's software to control individual bits within programmable registers in a front-end slave device, giving software developers more flexibility in how they apply configuration changes.

The MIPI RF Front-End Control Interface is used by RF device vendors, baseband and transceiver vendors, and mobile OEMs. It is a two-wire interface that uses unterminated single-ended CMOS I/Os for lower power. It can be used with a broad range of bus operating frequencies and features synchronous read capability, multi-master configuration, support for carrier aggregation and the use of multiple transceivers and dual-SIM designs, interrupt-capable slave functionality, and reserved registers that improve the efficiency of hardware and software development. MIPI RFFE v2.1 also extends trace lengths of RFFE buses, up to 45 cm from the standard 15 cm, in response to cellular, Wi-Fi and other wireless technologies being used in more than just handheld products such as smartphones.

The MIPI RF Front-End Control Interface is developed by the MIPI RF Front-End Control Working Group. The current release, v2.1, was released in 2018. It is a forward-looking solution that can be enhanced to address future RF front-end requirements, and it is backward compatible with earlier versions of the specification.

The specification is available only to MIPI Alliance members. For information about joining MIPI Alliance, visit Join MIPI.