By Bill Ingle, Beecham Research, Ltd.
The Wireless Innovation Forum, a non-profit “mutual benefit corporation” established in 1996 as The SDR Forum, defines Software-Defined Radio (SDR) as “Radio in which some or all of the physical layer functions are software defined.”
In other words, an SDR device uses software to be able to receive and transmit on multiple frequencies, filter RF signals, and manage digital to analog conversion, theoretically reducing the hardware — and cost — of covering multiple frequencies. Software-Defined Modems (SDM), a subset of SDR, could become very relevant to M2M with the move from 2G and 3G to LTE modules, with their multiple frequencies.
SDR and related technologies such as software-defined antennas and cognitive radio — a transceiver that automatically detects available channels and engages in dynamic spectrum management — began to become practical as powerful but small processors came into existence, per Moore’s Law.
An early example of SDR is the SPEAKeasy project, initiated in 1992, which resulted in demonstration radios for the U.S. Army. The first version, using proprietary software architecture, operated in frequencies from 2 MHz to 2 Ghz; a later open software version was smaller, lighter, less expensive, and enabled multiple simultaneous conversations and cross-channel connectivity. Radio data was processed with field programmable gate arrays (FPGA).
Before long, SDR could be implemented on a personal computer with an RF front end and sound card, the CPU doing signal processing. Meanwhile, ever smaller and more powerful embedded computers came into existence even as cellular technology arose, creating new possibilities. SDR enables the changing of radio protocols in real-time but the technology still has limits, chiefly in converting between analog and digital signals swiftly enough, with sufficient accuracy. All hinges on processor power.
SDR, Baseband, and M2M
Recent acquisitions highlight the perceived value of SDR technologies, whether for present or future M2M or baseband applications.
Cognovo and u-blox AG
Cognovo, a UK firm focused on LTE SDM, was acquired by Switzerland’s u-blox AG this year. U-blox also acquired LTE protocol developer 4M Wireless in 2012. U-blox, originally focused on GPS devices, has expanded into M2M wireless modules that incorporate positioning capabilities, based on its GPS expertise. Combining the Cognovo and 4M Wireless technologies with its own offerings will give u-blox the ability to offer SDM LTE M2M modules with similar positioning capabilities.
Icera and Nvidia
Icera Inc., based in the UK, is a fabless semiconductor firm focused on soft modem chipsets — baseband processors (Icera acquired Sirific Wireless, focused on CMOS RF, in 2008). Icera’s Levanto baseband chipset powers a number of mobile products made by companies such as LG, Sierra Wireless, Softbank, TeliaSonera, and Vodafone, among others. Icera was acquired by Nvidia in 2011.
Nvidia, based in Santa Clara, CA, is known for its Graphics Processing Units (GPUs) but also supplies Tegra, a System on a Chip (SoC) series incorporating an ARM processor and used in smartphones, tablets, and other mobile internet devices. By putting all of this together, Nvidia could become another entrant to the future M2M LTE module market.
Intel and Infineon Wireless Solutions
Intel has already announced work on SDR architecture for future baseband solutions but note Intel’s continuing efforts in M2M as described in Snaps #39 and #46. Might the two come together?
Intel gained SDR technology and expertise by acquiring Infineon’s Wireless Solutions group (WLS) early in 2011, acquiring an Infineon subsidiary, Comneon GmbH, as well. Like 4M Wireless, Comneon’s specialty is protocol stacks.
Interestingly, in 2009 Infineon announced that a “multi-standard mobile platform has been created based on Infineon-developed software-defined-radio technology. The SDR-enabled satellite-terrestrial handsets will operate with multiple cellular and satellite-based communications technologies including GSM, GPRS, EDGE, WCDMA, HSDPA, HSUPA and GMR1-2G/3G.” Technology powering such dual-mode handsets isn’t identical to M2M “dual-mode” devices but similarities can’t be dismissed.
LTE and SDR
The potential advantages of SDR for M2M really come into play with the advent of LTE, but aside from high-bandwidth applications, limited in number in today’s market, we are still some years from widespread LTE adoption — 2G and 3G technologies will prevail for some time yet.
M2M remains highly cost sensitive and the favored approach in 2G and 3G is not SDR. The RF unit on a Qualcomm chip, for example, can be configured to support practically any set of radio bands without SDR, even though Qualcomm’s Gobi technology is SDR-based. Meanwhile, neither Intel nor Nvidia offer M2M modules, while u-blox is a late entrant.
Eventually, M2M will feature LTE modules, even as Moore’s Law marches on. Size and cost issues will determine whether SDR is used on future modules.