The development of next-generation mobile devices is facing many challenges, not the least of which is a growing scarcity of spectrum and a variety of mobile access technologies worldwide. Currently deployed cellular standards include GSM, WDCMA, HSPA, CDMA, and TD-SCDMA, and their evolutions will merge into the long term evolution (LTE) standard. Smartphones will need to continue to be multi-mode devices that support 2G, 3G and 3G+ air interface standards, while adding support for 4G LTE as new networks roll out. Cellular antennas and RF front-end (the RF hardware in-between the RF transceiver and the antenna) must, therefore, support requirements from an increasing number of standards.
The Next Generation Mobile Network (NGMN) Alliance is a mobile telecommunications association of mobile operators, vendors, manufacturers and research institutes with a mission to develop a common view of solutions for the next evolution of wireless networks. In order to successfully deploy and operate mobile broadband on a global scale in the future, the NGMN has mandated the development of a single, operator-independent RF platform that supports all NGMN operator frequency bands.
An operator-independent RF platform will benefit network operators by providing easier access to multiple markets, compatibility with multiple OEM designs, and the platform’s support for network operators worldwide. Mobile device users will benefit from smartphones that offer excellent radio performance everywhere.
indie Answers the Mandate
EPCOS, a TDK company that is a leading manufacturer of electronic components, modules and systems, and Pulse Electronics, a leading antenna manufacturer, answered the NGMN mandate by co-designing and optimizing a breakthrough technology called indie.
Built on advanced EPCOS multi-feed RF front-end technology and cutting-edge antenna technology from Pulse, indie is the world’s first operator-independent RF hardware platform for global LTE smartphones. It enables for the first time global roaming and downlink inter-band carrier aggregation across LTE mobile devices. indie is a universal platform with a 16-band antenna that supports all widely used frequency bands worldwide and an advanced multi-feed RF front-end with a single hardware configuration can be used to serve the majority of operators with the same hardware configuration and no modifications.
indie’s unique design offers an enhanced user experience with seamless global LTE roaming, better radio performance, increased download data rates, improved battery life and fewer dropped calls.
The Design Challenge
The EPCOS and Pules design teams chose AWR’s Microwave Office® RF design software for the design of a three-feed antenna system and RF front-end module architecture to support global roaming in LTE networks and downlink inter- and intra-band carrier aggregation.
Microwave Office allowed indie designers to explore alternative design possibilities that resulted in the elimination of the region-specific duplexer matching that is necessary in single-feed architectures. In its place they were able to develop a three-feed architecture that enables universal operator-independent applicability. Moreover, this new architecture improves system performance by up to 2 db and facilitates wireless local area network (WLAN) interoperability, delivering better intermodulation linearity.
Ability to Collaborate Using a Common Design Platform
The unified data model at the core of the Microwave Office unique high-frequency design environment offers an intuitive, open and interoperable platform, enabling powerful and innovative technologies to integrate with best-in-class tools for each part of the design process. The Microwave Office design suite encompasses all the tools essential for high-frequency IC, PCB and module design, including linear circuit simulators, non-linear circuit simulators, electromagnetic (EM) analysis tools, integrated schematic and layout, statistical design capabilities and parametric cell libraries with built-in design-rule check (DRC).
Key to the success of the design of indie was the ability of the Pulse and EPCOS design teams to collaborate on the antenna design and the RF front-end module design using the single common platform provided by Microwave Office.
Pulse used AWR’s software to create circuit simulations of the antenna system and the matching circuits, as well as a general documentation platform.
Three-feed antenna system from Pulse
EPCOS used the software for the circuit simulations of the front-end module, including couplers, switches, duplexers, filters and diplexers, as well as for the modeling of the nonlinear passive duplexer.
RF front-end module from EPCOS
Ease of Use and Accuracy of Circuit Simulation
Microwave Office made it possible to accurately predict the performance of the antenna system together with the RF front-end module. The ease-of-use of the design software enabled easy setup of a single schematic for the testing of a large number of carrier aggregation pairs within the antenna and front-end module simulation.
Without detailed circuit simulation it would not have been possible to design and optimize the performance of the new RF hardware platform and to show that the indie platform provides significant benefits over traditional approaches. The accuracy of AWR’s circuit simulation showed that the front-end module’s performance compared well to real-world measurements. AWR’s online user-defined nonlinear models were flexible and easy to implement, and the quality of library components provided models that matched well with measurements.
Using Microwave Office as a “backbone” for the circuit simulation of both the antenna and the RF front-end module resulted in the design of the first universal RF hardware on the market. The product has been so successful it was nominated for a prestigious 2012 Global System for Mobile Communications (GSM) Association Global Mobile Award as Best Technology Breakthrough.
Posted by Janine E. Mooney, Editor
May 14, 2012