A New Wake-Up Modem for Low-Power Communications

Abstract

The demand for the Internet of things (IoT) technologies is growing rapidly. Hence, it is of paramount importance to address the battery problem associated with IoT devices. Although the required battery life of most of these devices is two or three years, in practice, the battery can last only a few months. The research presented in this paper aims to reduce the power consumption of IoT devices by using the wake-up modem proposed herein. To design low-power IoT devices, we analyze which parts of the devices consume the most power. Based on findings in the literature, the conventional IoT devices account for 60% of the total power consumption in the communication subsystem. Hence, the design of a low-power communication subsystem is critical for the low-power design of IoT devices. IoT devices have a very small amount of data for transmission; besides, data communication occurs very occasionally. Thus, the IoT device is in a standby mode most of the time. To reduce the standby mode power consumption, we propose a wake-up modem and verify its effectiveness and efficiency via computer simulation. Moreover, this paper suggests separating the wake-up modem to detect the wake-up preamble and the main modem for data recovery. While the detection block of the wake-up preamble is working in standby mode, only wake-up receiver blocks are operated, and the remaining receiver blocks are turned off. This greatly reduces the standby mode power consumption. In addition, the wake-up receiver can decrease the portion of the data receiver to the total receiver power consumption, which enables the data transceiver design without considering power consumption. The main radio is turned on when a wake-up preamble is detected. Considering that IoT devices are in standby mode most of the time, the proposed scheme can significantly reduce the overall power consumption since the proposed wake-up modem can reduce power consumption in standby mode significantly. Therefore, by applying the proposed scheme, the total power consumption for communication can be minimized in communication systems whose data transaction does not frequently occur, for example, IoT devices.