The DigRFSM Working Group was established as a MIPI Alliance Working Group in April 2007. The group’s scope is to develop specifications for wireless mobile Baseband IC (BBIC) to Radio Frequency IC (RFIC) interfaces in various mobile terminals. The ability to design one common high-speed interface that can be re-used for multiple applications is intended to help reduce design resource requirements and speed up the time-to-market for these terminals.
A BBIC to RFIC interface has unique requirements that are not typically met by other interface standards and the requirements of emerging air interface standards are not met by existing BBIC to RFIC interface standards. DigRFSM addresses a need for high-speed serial interface technology with high bandwidth capabilities developed specifically for a wide range of emerging mobile applications.
Committed to designing a sustainable specification for the long term, the WG is focused on efficiency, flexibility, and extensibility, while accommodating many variations in an overlying system design and providing interoperability at the interface level between compliant ICs.
The DigRFSM WG has also collaborated extensively with MIPI’s PHY WG to allow the use of a common M-PHYSM physical layer. This is a significant benefit given the increased performance requirements and complexity of next generation mobile terminals.
The DigRFSM working group released the MIPI Alliance Specification for DigRFSM v4 v1.10 in December 2011 and an updated MIPI Alliance Specification for DigRFSM 3G Dual Mode 2.5G/3G Baseband/RFIC Interface v3.09.06. An updated version DigRFSM v4 v1.2 will be available soon also supporting High Speed 3 based on M-PHY Gear 3 technology. DigRFSM v4 v1.2 is backwards-compatible with the previous (v1.10) version. DigRFSM v4 v1.2 now references the MIPI Alliance Specification for M-PHYSM v3.0 which is also backwards-compatible with M-PHYSM v1.0 and v2.0.
The DigRFSM v4 interface was designed in response to the rising deployment of high-bandwidth air interface standards requiring higher channel bandwidth, IQ sampling rates, IQ sample bit width, RX Diversity, MIMO and Carrier Aggregation. Described as the ‘link for the long term’, DigRFSM v4 was developed for mobile terminals that support next generation mobile broadband technologies such as Long Term Evolution (LTE) while supporting existing 3GPP standards such as 2.5G and 3.5G (EGPRS, UMTS, HSPA, etc.). Due to its large data rate and scalability, it is also suitable to cover other non-3GPP air interfaces over a common interface.
DigRFSM v4 is intended to increase bandwidth capabilities, minimize pin count, provide an efficient protocol for data transfer, and allow the use of multiple receivers and transmitters simultaneously. DigRFSM v4 provides a robust, high performance scalable digital link with low latency, high timing accuracy, power-saving operations and low EMI. In addition, it also natively handles MIMO configurations, receive diversity and carrier aggregation.
DigRFSM 3G is targeted for 2.5G GPRS / EGPRS as well as 3.5G UMTS chipsets including HSPA and also supports receive diversity in all cases.
Various silicon implementations of DigRFSM v4 and of DigRFSM 3G demonstrate the maturity of well-seasoned specifications.
|DigRFSM WG joins MIPI Alliance||Feb ‘07|
|WG Charter approved by MIPI Board||Mar ‘07|
|DigRFSM 3G v3.09.04 approved||July ’08|
|DigRFSM v4 v0.70.01||Sept ’09|
|DigRFSM 3G v3.09.05 approved||April ‘10|
|DigRFSM v4 v1.00.00 approved||May ‘10|
|DigRFSM 3G v3.09.06 approved||Aug '11|
|DigRFSM v4 v1.10 approved||Dec '11|
|DigRFSM v4 v1.2||in preparation|
Dr. Dietmar Wenzel - Intel Corporation