Marmote SDR: Experimental Platform for Low-Power Wireless Protocol Stack Research

Abstract

Over the past decade, wireless sensor network research primarily relied on highly-integrated commercial off-the-shelf radio chips. The rigid silicon implementation of the radio stack restricted access to the lower layers; thus, research focused mainly on the medium access control (MAC) layer and above. SRAM field-programmable gate array (FPGA)-based software-defined radios (SDR), on the other hand, provide a flexible architecture to experiment with any and all layers of the radio stack, but usually require desktop computers and draw high currents that prohibit mobile or longer-term outdoor deployments. To address these issues, we have developed a modular flash FPGA-based wireless research platform, called Marmote SDR, that has computational resources comparable to those of SRAM FPGA-based radio platforms, but at a reduced power consumption, with duty cycling support. We discuss the design decisions underlying Marmote SDR and evaluate its power consumption. Furthermore, we present and evaluate an asynchronous and multiple access communication protocol specifically designed for data-gathering wireless sensor networks

MIGOU: A Low-Power Experimental Platform with Programmable Logic Resources and Software-Defined Radio Capabilities

“…Specifically, these platforms are: YetiMote [16]: This platform was chosen as a representative traditional wireless sensor node. Its architecture is based on a STMicroelectronics STM32L476RE microcontroller and three COTS radio transceivers, two STMicroelectronics SPIRIT1 operating in the 433 MHz and 868 MHz bands, and a Texas Instruments CC2500 for the 2.4 GHz band. MarmotE SDR [29]: This platform was selected as a representative low-power SDR system, which was specifically designed to be battery-powered. In addition, amongst the two presented in Section 2, this is the one with more detailed power consumption data.…”

“…MarmotE SDR [29]: This platform was selected as a representative low-power SDR system, which was specifically designed to be battery-powered. In addition, amongst the two presented in Section 2, this is the one with more detailed power consumption data.…”

“…MarmotE SDR [29] and µSDR [30] are two low-cost and sub-watt SDR platforms, which were specifically designed to be battery-powered. In terms of hardware architecture, both are practically equivalent.…”

“…However, it is still possible to go further. When analyzing the consumption data of MarmotE SDR [8,29], it can be seen that the radio transceiver is responsible for more than half of the power consumption in those modes in which it is active, reaching 60% of the total consumption in the receive mode and 86% in the transmit mode. Therefore, this component constitutes one of the most critical parts of the design, with a high impact in the overall energy utilization.…”

“…This device integrates a microcontroller subsystem (MSS), based on an ARM Cortex-M3 processor, and a flash-based FPGA. This kind of FPGA has been proved to have faster wake-up times and to be more energy-efficient than SRAM-based FPGAs [29]. In addition, the SmartFusion2 family, unlike the SmartFusion, supports a low-power mode of the FPGA fabric, which is known as the Flash*Freeze mode.…”