The benefit of a 16-channel deployment in the EU868 bands

Summary

This document explores the advantages of using 16-channel networks in EU868 deployments. It highlights how 16-channel networks offer greater capacity compared to 8-channel networks, particularly for join (JOIN) traffic and exchanged UL/DL traffic. Additionally, the document addresses device considerations, network memberships, and deployment of mixed 8- and 16-channel gateways.

In the Appendix we recall the principles of the LoRaWAN protocol.

Key Questions Addressed:

• What are the benefits of using a 16-channel LoRaWAN network versus an 8-channel network in EU868 deployments?
• What considerations should be made for devices in a 16-channel deployment?
• How can an EU868 network be enabled to operate on more than 8 channels, and what are the alternatives for distributing devices over more channels?
• What are the considerations for deploying gateways in a 16-channel LoRaWAN network in EU868?

Gateways: 16 Channels or 8 Channels?

Let’s imagine that you have two types of LoRaWAN networks: one with 8 channels and another with 16 channels. The network with 16 channels has greater capacity because it has more channels available to transmit data, allowing communications to be spread over more channels and reducing congestion.

In EU868 (Europe) networks, join traffic (when devices join the network) is limited to 3 channels by default. These channels are often the first to be impacted by interference because they are used for all new connections.

By using more channels for regular traffic (sending and receiving data), we reduce the load on these default channels. It’s like adding more lanes on a highway to reduce traffic congestion.

By using channel masking bits to block in-session traffic (i.e. after devices have joined the network) from using default channels, several benefits are achieved:

• The default channels are much less congested.
• In an 8-channel network, using the default channels reduces the overall network capacity by 5/8.
• In a 16-channel network, avoiding the default channels for session traffic increases the overall network capacity by 13/8.

Comparing fairly, the capacity of a 16-channel network is 13/5 times that of an 8-channel network.

If starting with an 8-channel network, it is good practice to use the MAC LINKADRReq command to prevent session traffic from using the default channels. By moving to a 16-channel deployment, we can increase the network capacity by almost 3 times.

In summary, using a 16-channel gateway  and avoiding default channels for regular traffic reduces congestion and increase LoRaWAN network capacity by 3x.

Do Devices Support a 16 Channel Configuration?

The myth that it’s impossible to operate on more than 8 channels in an EU868 deployment is false. In reality, most devices can use more than 8 channels in EU868 networks.

Here’s how it works:

Method 1: CFList and NewChannelReq

1. CFList (Channel Frequency List) : During the joining process (JOIN), you can communicate up to 5 additional channels using the CFList list . This could be the origin of the myth, because 3 default channels + 5 additional channels = 8 channels.
2. NewChannelReq (New Channel Request ) : You can add more channels using the NewChannelReq command . This feature has existed since the first LoRaWAN specifications.
3. Communication after joining (JOIN) : To add additional channels, one must communicate with the device after the connection process, during the session. This is done by sending a 5-byte MAC (Media Access Control) command per additional channel. Up to three of these MAC commands can be grouped in the FOPTS field of a DL message.

In summary, configuring an EU868 network to use more than 8 channels by combining CFList and NewChannelReq commands is entirely possible.

Method 2: Grouping Devices

1. Dividing Devices into Groups : Each group uses a different set of channels. For example, with three groups:

• Group A: Uses the 3 default channels + channels 3, 6, 9, 12, 15.
• Group B: Uses the 3 default channels + channels 4, 7, 10, 13, 14.
• Group C: Uses the 3 default channels + channels 5, 8, 11, 14, 13.

2. Capacity Augmentation : This practice allows device load to be distributed across more channels, effectively increasing network capacity. Spreading interference limitations across more channels reduces the impact on each individual channel.
3. Using CFList : This method is simple because it always uses the CFList functionality to inform the devices of the 5 additional channels they should operate on.

In summary, by dividing devices into groups and using a different set of channels for each group, one can exploit the capacity of the EU868 network beyond the traditional 8 channels, while using the CFList functionality to configure the additional channels. This approach makes it possible to improve interference management and optimize the use of available spectrum.

Twice 8 Channels or Once 16 Channel Gateway?

What is the best to deploy? Here are some considerations:

1. Additional Channels Benefit: More channels mean more capacity, allowing for greater scale in your solution, deployment, or network. Of course, this is not always necessary, but it is an option to consider for applications that require high capacity or extensive coverage.

1. Two 8-Channel Gateways: If more channels are needed, you can deploy two 8-channel gateways in the same location (co-located). Configure one to cover 8 channels and the other gateway to cover the remaining 8 channels.

3. Single 16-Channel Gateway: equivalent in terms of channels, a single installation instead of two, lower consumption.

By correctly configuring both gateways, you can effectively create a solution equivalent to a 16-channel gateway, in terms of coverage and capacity.

Mixed Network: 8 and 16 Channels Gateways

A mixed 8 and 16-channel solution can work together effectively. Here’s how:

1. Selecting the Best Gateway : In the same way that a network server (NS) can select the best gateway to transmit messages ( downlinks ) to a device, the network server (NS) can inform devices if they need to operate on 8 channels or 16 channels depending on recent UL activity.
2. Informing Devices: Devices are informed about the 16 channels using a single LinkADRReq MAC command via the channel mask bits.
3. Stationary Devices : For stationary devices, this change is rare or part of a configuration setting. Once configured to use the best setup, stationary devices typically continue using that configuration unless an update is necessary.
4. Mobile Devices : Configuration is expected to change as devices move between coverage areas. Mobile devices might revert to 8-channel operation until they remain in a dense environment for a period (e.g., mobile assets returned to a storage area).

In summary, 8-channel and 16-channel gateways can work together using intelligent channel selection and device configuration. The network server plays a key role in managing these configurations to optimize network performance based on device needs and coverage conditions.

Annex

The LoRaWAN protocol, which is based on LoRa (Long Range) physical layer technology, is a wireless communication protocol designed for long-range, low-power sensor networks. It is particularly suitable for Internet of Things (IoT) applications.

In the context of LoRaWAN, the term “JOIN channels” refers to the frequency channels used by devices to join a LoRaWAN network. This joining process is a crucial for setting up communication between a device (end-device) and a LoRaWAN network.

Here is a detailed explanation of JOIN channels and how they work:

1. Join Process :

• Before sending or receiving data, the device must identify itself and derive session keys necessary for message encryption and integrity checks.
• The device sends a join request to the network via a JOIN channel.
• This request is received by one or more LoRaWAN gateways and transmitted to the join server (JS) via a network server (NS).

2. Join Channels:

• JOIN channels are specific predefined frequencies used specifically for the network reentry process.
• These channels are defined by local radio spectrum regulations and may vary by region.
• In the EU868 regions, for example, the JOIN channels are defined as 868.1, 868.3, and 868,5 MHz.

3. Security :

• The join process is secured using encryption keys. The device uses a shared secret application key (AppKey) to derive the session keys.
• The Join Server shares this secret application key and derives identical session keys for the network use.
• The join process is successful when the “Join Accept” is received by the device and both sides have derived the session keys. Regular messaging, with encryption and integrity checking, can then proceed.

In summary, the JOIN channels are essential elements of the LoRaWAN protocol that allow devices to identify themselves to the network and derive the keys necessary to establish secure communication. This process is crucial to guarantee the security and reliability of data exchange in LoRaWAN networks.

Channel and Frequency Identifications

In the LoRaWAN protocol, JOIN channels are specific frequency channels used by devices to join a LoRaWAN network. These channels are defined by local radio spectrum regulations and may vary by region. Here are some examples of JOIN channels for different regions

Europe (868 MHz band):

• Channel 0, 1, and 2: 868.1 MHz, 868.3, and 868.5 MHz

It is important to note that JOIN channels are generally used in “LoRa only” mode and not in “FSK” (Frequency-Shift Keying) mode. The parameters of JOIN channels, such as bandwidth, sampling rate, and transmit rate, may also vary depending on local regulations and network configurations.

In Europe, in the 863-870 MHz frequency band, the number of available LoRaWAN channels depends on the specific ETSI regulations (European Telecommunications Standards Institute) and technical characteristics of LoRa technology.

For LoRaWAN networks in Europe, there are typically 16 channels available for data communication, each with a bandwidth of 125 kHz. These channels are used for sending and receiving data once devices have joined the network.

In summary, in Europe there are 16 standard data channels for LoRaWAN, including three dedicated channels for join processes, making a total of 16 LoRaWAN channels used for different network operations.

The Role of the Channel Mask

In the LoRaWAN protocol, the “channel mask bits” (“channel mask”) is a mechanism used to enable or disable specific channels among those available for communication. This allows precise management of the channels a LoRaWAN device uses for data transmission.

The channel mask is represented by a set of bits, where each bit corresponds to a channel. If a bit is in state “1”, the corresponding channel is activated; if the bit is in state “0”, the channel is deactivated. The number of bits in the mask matches the number of channels the device can use.

For example, if a European LoRaWAN network has 16 data channels, the channel mask will consist of 16 bits. A channel mask of “FFFF” in hexadecimal (or “1111111111111111” in binary) would indicate that all channels are enabled, while a mask of “0000” would indicate that all channels are disabled (Note this setting is for educational purposes only and is impractical in real use).

Purpose of the Channel Mask:

Network Optimization: Network operators can use channel masking to manage congestion or optimize spectrum usage by turning channels on or off as needed.

The channel mask is configured by the Network Server and transmitted to devices via the LoRaWAN LinkADRReq MAC command, either on Port 0 with the MAC command in the application payload or piggy-backed in the FOPTS field of regular frames. Devices adhere to this mask when selecting channels for communication. This configuration can be dynamic, allowing updates by the network server to adapt to changing network conditions or regulatory requirements.

Let TEKTELIC be your trusted partner in transforming your operations and boosting efficiency. Stay updated with TEKTELIC’s expert insights and cutting-edge technology. To learn more, contact our experts.