Lime Microsystems Unveils the LimeSDR Micro, an M.2 Expandable SDR with Vector Accelerator
First FPGA-free LimeSDR is now crowdfunding, with an NXP baseband processor offering the ability to accelerate vector DSP work on-device.
Software-defined radio (SDR) specialist Lime Microsystems has opened crowdfunding for a new entry in the LimeSDR family, the LimeSDR Micro — turning the company's LMS7002M field-programmable radio-frequency chip into an FPGA-free M.2 module with integrated acceleration.
"LimeSDR Micro is a next-generation, high-performance, software-defined radio (SDR) with integrated vector signal processing acceleration, packaged in a compact M.2 2280 form factor," Lime Micro explains of the new board. "Featuring an NXP LA9310 baseband processor and Lime Microsystems LMS7002M transceiver, LimeSDR Micro is an all-software-programmable platform with market leading size, weight, power, and cost. LimeSDR Micro may be used as a classic SDR with all processing carried out on the host computer, or the LA9310 Vector Signal Processor Accelerator (VSPA) may be used to offload physical layer processing and thereby significantly reduce load on the host CPU, while simultaneously reducing power consumption and enabling the creation of highly energy-efficient solutions."
The LimeSDR Micro is the latest in the LimeSDR family, which also includes full-size add-in boards and compact external USB devices. It shares the same LMS7002M chip as its stablemates, meaning support for frequencies from 30MHz to 3.8GHz, offering a one-transmit two-receive (1T2R) setup expandable to one-transmit four-receive (1T4R) with optional add-ons. It's supported by the same software as other LimeSDR boards, but it differs in one major aspect beyond the move to an M.2 form factor: it doesn't have an on-board FPGA.
Instead of an FPGA, the LimeSDR Micro is the first to use a dedicated NXP LA9310 baseband processor — but that doesn't mean the range's famous flexibility has fallen by the wayside. The NXP chip includes an on-board vector signal processor accelerator (VSPA), which can be used as either an accelerator for the host or for the SDR to handle signal processing tasks on-device.
"NXP also provide a collection of open source VSPA kernels for functions such as FFT, inverse FFT, CRC generation, FIR filters, mixer, and modulation/demodulation of up to 1024-QAM," Lime Micro adds. "With selected kernels accompanied by Matlab scripts for generating test vectors. The DSP kernels may be used to both extend the default firmware and in the creation of entirely new firmware, which might implement physical layer processing for a particular wireless standard, for example."
As with previous LimeSDR launches, the LimeSDR Micro is open hardware: schematics, board layouts, manufacturing files, and the complete design database will be published under an open-hardware license during the device's crowdfunding campaign, Lime Micro has promised, with the source code for the control and digital signal processing firmware already available on GitHub under the permissive BSD three-clause license.
The LimeSDR Micro is now funding on Crowd Supply, with prices starting at $199 for "early bird" backers of the base board, rising to $249 without or $299 with an optional Global Navigation Satellite System (GNSS) receiver. A LimeFEA HF Micro add-on adds a third receive path with 0-30MHz frequency range for an extra $199, while the LimeSDR Micro Pro bundles both boards with a metal enclosure and USB 4.0 adapter board at $749 for external use. All boards are expected to start shipping at the end of September this year.