Optimized Battery Life and LPWA: Latency and Local Connectivity

This is the second post in our two-part series focused on how to optimize device battery life when leveraging low power wide area (LPWA) networks. The first post focused on eDRX and PSM technologies – you can catch up by reading it here. 

Latency is a large driver in the enhancement of battery life in IoT devices, especially in the rise of Massive IoT use cases. We are seeing a lot of relatively new development in supporting battery life, including low power wide area (LPWA) networks and power management techniques such as eDRX and PSM. 

Early IoT devices were characterized by high power consumption, were designed for frequent network communication, and lacked power management beyond the very basics. The demand for devices to be deployed permanently without the need for replacing batteries has converged with more advanced hardware and technology and created a unique opportunity for Massive IoT – millions of simple, battery-optimized devices geographically dispersed and powering thousands of use cases. 

An element not often discussed when detailing the supporting elements behind battery-optimized LPWA connectivity and Massive IoT is the role of latency. 

What is Latency? 

Data latency refers to the delay between the transmission of data from a source and its reception at the destination. It encompasses various types of delays, including propagation delay (time for data to travel through the medium), transmission delay (time to push data into the medium), processing delay (time for network devices to handle data), and queuing delay (time waiting in device queues). 

Factors affecting latency include distance, bandwidth, network congestion, processing power, transmission medium, and protocol overhead. 

Network latency can manifest in several ways:

Data transmission: Network latency could lead to delays in data transmission, lowering response and declining operational efficiency. This delay could be critical in real-time applications that require immediate data communication. 

Device lifespan: High network latency might cause constant strain and negatively affect the longevity of IoT devices. As a result, appliances might be overheating and have a shorter lifespan. 

User experience: Network latency would cause poor user experience for applications that demand real-time processing as delays in data transmission will confuse users and question the functionality of the IoT devices. 

Power consumption: IoT devices often function on limited battery power. Higher network latency will require more power for transmitting data, leading to increased power consumption and reduced battery life. 

For the purposes of this post, we’ll focus on latency’s impact on power consumption. 

Latency and Power Consumption

The speed at which data is transmitted doesn’t initially seem like it could impact a device’s overall battery life. However, increased latency usually results in higher power consumption as the device remains active longer, waiting for data or connection, which impacts overall battery efficiency.

Higher latency in IoT devices typically means that these devices spend more time waiting or inactive, which can lead to increased battery consumption. When a device has high latency, it often needs to keep its radio or network interfaces active for longer periods to maintain connections or wait for data transmission. This constant activity drains the battery faster than devices with lower latency, which can transmit and receive data more efficiently and return to a low-power state faster. Additionally, high latency can lead to frequent wake-up cycles or retries in communication, further depleting battery life.

An example of this would be an IoT use case in logistics management. In a warehouse setting, for example, IoT devices such as inventory tracking sensors or smart shelving rely on data transmission to monitor stock levels and environmental conditions. 

If a device experiences high latency, it may need to stay active longer to ensure successful data transmission or to wait for responses from the central system. This extended wake time increases power consumption and drains the battery more quickly. 

High latency might also cause data packets to be delayed or lost. The device may then need to resend information multiple times, which consumes additional battery power for these retries. 

Inefficient communication might require more frequent wake-ups to check for updates or maintain a connection, as well. 

Largely speaking, the mere length of time that a device needs to be awake due to the data transmission speed is the largest area of concern and one that is approached through the use of local hubs, or packet gateways, to create a global mesh of PGWs for data transmission as close as possible to the source. 

Latency and Proximate Packet Gateways 

So what exactly is a packet gateway? All networks have boundaries that restrict communication to directly connected devices. A gateway must interact with devices, nodes, or networks beyond this boundary. A gateway typically functions as a combination of a router and a modem.

Located at the network’s edge, the gateway handles all data traffic, both internal and external. When a network needs to communicate with another network, the data packet is sent to the gateway, which then routes it through the most efficient path to its destination. Besides routing, a gateway also maintains information about the internal paths of its own network and any additional networks it interfaces with.

It’s simpler to say that data transmission can be handled and routed to the cloud application through local processing. The traditional method routes data on the home network and then to the cloud application. 

Let’s imagine an organization that is based in Europe and has devices deployed in the United States and Europe, both of which use the home network in Europe. The devices in Europe do not suffer latency issues because they are running on the home network, and the latency in transmitting that data is normal. However, the US devices must send their data on the home network through Europe and back to the United States. This creates high latency, where the device is awake longer than is necessary, waiting for the transmission to be complete. 

Repeatedly, though they may be performing exactly the same tasks, these devices undergo differing periods of latency to the point that the European devices have a lifecycle of 5 years and the United States devices have a lifecycle of 2 years. 

This organization is then tasked with two sets of logistics for the same batch of devices, which increases complexity, detracts from the overall efficacy of their solution, and may even make it difficult to manage or scale their US operations. 

Local Connectivity on a Global Scale

Local connectivity can significantly reduce latency, as explained in the above example. At floLIVE, we have a global infrastructure based on local packet gateways or points of presence that creates a local connection but on a local scale. More than 40 local points of presence support our global network infrastructure and can significantly reduce latency by having data transmission occur closest to the source through a local connection that is not reliant on roaming via a home network. 

The above example is not far-fetched either. The device battery can be extended by more than double due to reduced latency when communicating data.

When your Massive IoT solutions rely on optimized battery life, and you’ve chosen LPWA networks and eDRX or PSM to get the most out of your battery life, it makes perfect sense to include latency in the equation. The best way to get the lowest latency that supports long battery life is through local connectivity, which can be achieved on a global scale through simple management and a single SKU. 

Learn more about how floLIVE can support you with our global network infrastructure, which we own and operate. Just reach out to get the conversation going.