One of the biggest challenges for any wireless technology in providing reliable data communication is interference. Unlike wired data communications technologies, wireless technologies must share the transmission medium and multiple devices may try to communicate over the same wireless spectrum, in the same general area, and at the exact same time. When this happens, in-air collisions between data packets occur which can make a packet unreadable by the receiving device and effectively lost.

This challenge is especially true in unlicensed spectrum bands, such as the global ISM band, where a communications technology needs to accommodate potential interference from other devices using the same communications technology, as well as devices using other communications technologies that operate in the same band.

Channels that are noisy and busy are dynamically tracked and avoided.

For example, Bluetooth® technology operates in the same 2.4 GHz ISM frequency band as Wi-Fi and technologies that utilize the IEEE 802.15.4 standard. As a result, it’s possible for a packet being transmitted between two Bluetooth devices to be corrupted or lost if it collides with a packet being transmitted at the exact same time and frequency channel between other in-range Bluetooth, Wi-Fi, or 802.15.4 devices. Other devices utilizing the 2.4 GHz band can also cause unwanted electromagnetic noise in the environment, including lights, microwave ovens, baby monitors, and garage door openers, to name just a few.

There are many techniques for mitigating interference. For a detailed discussion on the mitigation techniques, Bluetooth technology uses to increase reliability, check out Martin Woolley’s paper on Understanding Reliability in Bluetooth Technology. In this article, we will look at how Bluetooth technology overcomes potential interferers and enables reliable wireless data communication by using adaptive frequency hopping and small, fast data packets.

Small, Fast Packets

When trying to avoid collisions, it’s best to be small and fast. For example, when compared to other low-power wireless mesh networking technologies, Bluetooth® packets are typically half the size and four times faster. Having small, fast packets enables more efficient use of spectrum and significantly lowers the probability of collisions.

Bluetooth® packets are hard to hit.

As Szymon Slupik, CTO at Silvair and Chair of the Bluetooth Mesh Working Group, often says, the math is simple: the shorter the packet the fewer collisions. The reliability of any wireless system is all about spectral efficiency. According to Slupik, the size of Bluetooth Mesh packets is one of the biggest reasons why Bluetooth Mesh networking is “the first wireless standard capable of meeting the enormous expectations of the IoT era.”

Slupik is not alone in his praise for the packet. Woolley references the Bluetooth Mesh packet in relation to scalability and capacity of a high-density device network. As Woolley says

The less radio airtime a packet requires, the lower the probability of a collision. The small packet size of Bluetooth® Mesh and the high symbol rate of the Bluetooth LE radio reduce the required airtime for a packet and means that Bluetooth Mesh networks fare well in this respect.

But Bluetooth packets don’t just have size and speed on their side. They’re also good at avoiding conflict.

Adaptive Frequency Hopping

Spread spectrum techniques can increase the resiliency of a wireless technology in busy radio environments where collisions and interference are more likely to occur. Adaptive Frequency Hopping is a unique spread spectrum technique Bluetooth technology utilizes to avoid interference.

To understand how Adaptive Frequency Hopping works, it helps to look at how Bluetooth technology divides the 2.4 GHz ISM band. First, like many wireless communication protocols, Bluetooth technology uses more than one radio channel. Bluetooth Low Energy (LE) divides the 2.4GHz ISM radio band into 40 channels, while Bluetooth BR/EDR divides it into 80 channels.

Bluetooth technology also hops between transmission channels to further decrease the probability of collisions with other in-range transmissions. Frequency hopping frees up more radio capacity for messages, making communication more reliable. Frequency hopping is not necessarily unique to Bluetooth technology. But what happens next is.

Adaptive Frequency Hopping adds intelligence to frequency hopping and enables Bluetooth packets to adapt to avoid active, congested channels. Channels that are noisy and busy are marked and not used. The list of reliable channels and busy channels can change quickly, as other wireless communication devices and noise in the environment come and go. Adaptive Frequency Hopping allows Bluetooth technology to dynamically track which channels are functioning best and find the most reliable path.

Bluetooth® packets avoid conflict.

Reliable by Design

As you can see, Bluetooth technology is capable of achieving highly reliable communication in even the most challenging circumstances. These two methods provide a glimpse into the techniques and features Bluetooth® technology offers to help developers address the challenge of interference. Reliability in Bluetooth technology is more than just the sum of the reliability of its parts; the technology was designed with reliability in mind. For a detailed discussion on the many mitigation techniques Bluetooth technology uses to increase reliability, download Understanding Reliability in Bluetooth Technology.


How Bluetooth® Technology Makes Wireless Communication Reliable

Learn about the challenge of wireless interference and the techniques Bluetooth technology uses to overcome it.


Comparing The Different Wireless Technologies For Condition Monitoring Applications In IIoT

There are several wireless technologies to choose from, each with their advantages and disadvantages…

The 3 Updates Application Developers Need To Know About Bluetooth®︎ Core Specification Version 5.3

Developers have more flexibility and configuration options than ever with the Bluetooth Special Interest…

10 Resources That Showcase the Range and Reliability of Bluetooth Technology

Despite the overwhelming adoption of Bluetooth® technology across a wide range of global solutions…

Bluetooth Range and Reliability: Myth vs Fact

For years, Bluetooth® technology enhanced the lives of millions of people around the world, becoming…

How Bluetooth Technology Enables Reliable, Long- Range Solutions

The success of Bluetooth® technology in the wireless communication industry is illustrated by its…

Top Bluetooth Developer Resources of 2020

Every year, the Bluetooth® developer community challenges the limits of wireless connectivity, and each…

How Bluetooth Technology Uses Adaptive Frequency Hopping to Overcome Packet Interference

Interference is one of the biggest challenges for any wireless technology in providing reliable…

How Bluetooth Mesh Enables Scalable, Reliable Low-Power Wireless Networks

Silvair, a strong advocate for Bluetooth Mesh and a leading contributor to the Bluetooth Mesh…

Understanding Reliability in Bluetooth® Technology

Download this detailed discussion of the issues and factors that impact the reliability of…

Bluetooth Mesh Networking Highlights and Features

This white paper provides an overview of the Bluetooth Mesh Profile and highlights some…

Advanced Bluetooth® Technology – Under the APIs

Bluetooth technology has changed enormously since its initial release about twenty years ago. Communication…

Low Latency, Deterministic Bluetooth Technology

Watch Pelle Svenson of ublox provide an overview of low latency deterministic control using…

Bluetooth Deployment in Hospital Settings

Download this white paper to see how advancements in Bluetooth performance and reliability in…

 Get Help