LoRaWAN® Networks with Optimal Power Management

In the realm of Internet of Things (IoT) and low-power wide-area networks (LPWANs), LoRaWAN® stands tall as a prominent protocol enabling long-range wireless communication with minimal energy consumption. If you often get confused about battery life while deploying a LoRaWAN® Network, then this article is for you.

Since, battery life is a critical aspect to consider in LoRaWAN® deployments. Efficiently estimating battery life is crucial for maintaining reliable and sustainable operations in IoT devices. In this article, we delve into the factors that influence battery life in LoRaWAN® networks and explore how they can be calculated, empowering businesses to optimize power usage and prolong device autonomy.

·         Transmission Frequency:

The frequency at which data is transmitted has a significant impact on battery life. LoRaWAN® devices can be programmed to send data at regular intervals or triggered by specific events. Increasing the transmission frequency will consume more power as the device needs to activate its radio module more frequently.

·         Radio Interference and Transmission Retries

A radio transmission is a combination of data transmission and a successful response (ACK) from LoRaWAN® Gateway. The significant amount of radio interference may have caused much difficulty in data transmission and listening and results in a longer data transmission. If the LoRaWAN® Gateway fails to receive and acknowledge data, the LoRaWAN® Sensors or Sensor Node will retry until they receive a successful ACK from it. This process will drive negative influence to battery life. To better protect your LoRaWAN® Sensors, Sensor Nodes, and batteries, try to use channels that have little radio interference from other devices.

·         Data Payload:

The size of the data payload transmitted by a LoRaWAN® device affects battery life. Larger payloads require more energy to transmit, leading to increased power consumption. Optimizing the payload size can help conserve energy and extend battery life.

·         Transmit Power:

The transmit power level determines the range of communication between LoRaWAN® devices and gateways. Higher transmit power settings consume more energy, as the device requires more power to transmit signals over longer distances. Adjusting transmit power to match the required range can help conserve battery life.

·         Sleep Duration:

LoRaWAN® devices can be programmed to spend most of their time in a sleep mode to conserve power. The sleep duration, which refers to the period when the device remains inactive, plays a vital role in battery life calculation. By reducing the sleep duration, the device spends more time awake and consuming power.

·         Duty Cycle Limitations:

LoRaWAN® networks enforce duty cycle limitations to prevent network congestion and interference. These limitations restrict the amount of time a device can transmit within a specific time window. Adhering to these limitations ensures network fairness and efficient utilization of battery power.

·         Environmental Factors:

The operating environment of LoRaWAN® devices can significantly impact battery life. Factors such as temperature, humidity, and signal interference can affect power consumption. Extreme temperatures can cause batteries to discharge faster, while signal interference may lead to retransmissions, consuming additional energy.

·         Battery Capacity:

The capacity of the battery itself determines the amount of energy available for device operation. Battery capacity is measured in milliampere-hours (mAh) or watt-hours (Wh). The higher the battery capacity, the longer the device can operate before requiring a recharge or battery replacement.

Consider using the following generic calculator to estimate battery life and capacity:

Variables:

C = Battery capacity (mAh)

BL = Battery life (years)

Is = Current in sleep mode (mA)

Itx = Current in transmit mode (mA)

Irx = Current in receive mode (mA)

Imeas = Current in measurement mode (mA) [depends on technology and application]

Ttx = Time in transmit mode (ms)

Trx = Time in receive mode (ms)

Tmeas = Time in measurement mode (ms) [depends on technology and application]

Ta = Total active time (ms)

Ta = Ttx + Trx + Tmeas

U = Usable capacity after accounting for self-discharge (%)

N = Number of device activations per day

cU = Capacity after accounting for discharge rate (mAh) = C * (U/100)

T = Milliseconds per hour = 3600000

cA = Active capacity usage per day = N * (Ttx * Itx + Trx * Irx + Tmeas * Imeas) / T

cS = Sleep capacity usage per day = Is * (24 - ((Ttx + Trx + Tmeas) * N / T))

cT = Total capacity consumed per day = cA + cS

Battery Life (days) = (cU / cT) / 24

Battery Life (years) = days / 365.24

By inputting the relevant values for each variable into this calculator, you can calculate the estimated battery life and capacity based on your specific application and technology.

Understanding the factors that influence battery life in LoRaWAN® networks is essential for optimizing power consumption and ensuring prolonged device autonomy. Efficient battery management plays a pivotal role in achieving sustainable and successful deployments in the ever-expanding world of LoRaWAN®-enabled IoT.