On the Energy Consumption and Ranging Accuracy of Ultra-Wideband Physical Interfaces

Abstract

Ultra-wideband (UWB) communication is attracting increased interest for its high-accuracy distance measurements. However, the typical current consumption of tens to hundreds of mA during transmission and reception might make the technology prohibitive to battery-powered devices in the Internet of Things. The IEEE 802.15.4 standard specifies two UWB physical layer interfaces (PHYs), with low-and highrate pulse repetition (LRP and HRP, respectively). While the LRP PHY allows a more energy-efficient implementation of the UWB transceiver than its HRP counterpart, the question is whether some ranging quality is lost in exchange. We evaluate the trade-off between power and energy consumption, on the one hand, and distance measurement accuracy and precision, on the other hand, using UWB devices developed by Decawave (HRP) and 3db Access (LRP). We find that the distance measurement errors of 3db Access devices have at most 12 cm higher bias and standard deviation in line-of-sight propagation and 2-3 times higher spread in non-line-of-sight scenarios than those of Decawave devices. However, 3db Access chips consume 10 times less power and 125 times less energy per distance measurement than Decawave ones. Since the LRP PHY has an ultra-low energy consumption, it should be preferred over the HRP PHY when energy efficiency is critical, with a small penalty in the ranging performance. Index Terms-Ultra-Wideband (UWB), Distance Measurement, Accuracy, Energy Efficiency 1 We will refer to the 3db 3DB6830C (Release 2016) and the Decawave DW1000 (Release 2014) as the 3db and Decawave ICs, respectively.

High-Accuracy Ranging and Localization With Ultrawideband Communications for Energy-Constrained Devices

“…In our previous work [1], we found that 3db devices had a PDR of 0.9 up to 116 m, but we did not measure the PDR at longer distances because of the limited space. Similarly, in this experiment, we did not measure the PDR beyond 220 m.…”

“…In [1], we compared the maximum range of 3db devices with the one of Decawave devices operating in the long-range mode (Mode 3) and we found that they had a similar PDR over the covered area. Decawave devices in the long-range mode have a packet duration about 10× larger than in the short-range mode and therefore also a higher energy consumption.…”

“…In our previous work [1], we used Decawave devices integrated in the EVK1000 evaluation kit which allowed more configurations and used the DS-TWR. There, we decided to use the long-range mode (Mode 3), in order to attain a similar range as with 3db devices.…”

“…Therefore, a Decawave tag will consume 180 µJ per SS-TWR during transmission and reception, while a 3db tag will consume 28 µJ (including the transition times), so 6.4 times less energy. When placed in the long-range mode (for instance, mode 3), the packet duration of Decawave devices increases to 3487 µs which is about 10× larger than that of 3db devices, causing them to consume at least 100× more energy [1]. The difference between these modes is the maximum range at which the devices can communicate, so in the next section we will compare the range of 3db and Decawave devices.…”

“…In our previous work [1], we compared for the first time the power and energy consumption and the ranging performance of LRP and HRP devices using two commercially-available UWB devices: the Decawave DW1000 IC (HRP) 1 and the 3db Access 3DB6830C IC [14] (LRP) 2 . For the ranging performance, we used a database of distance measurements acquired with 3db devices and compared their statistics with results obtained with Decawave devices from the literature.…”