In the wireless world, devices that connect today, may not connect tomorrow

It may not come as a huge surprise that as an antenna company specialising in antennas for challenging platforms (on the body, or on metal), we frequently hear about problematic wireless performance. Companies often contact us when their products’ wireless performance isn’t reliable, an issue usually discovered when the product is out in the real world, facing real-world RF challenges that pre-release testing didn't uncover.

An increasingly common scenario is when previously reliable wireless systems, suddenly experience connectivity problems making the wireless functionality redundant, and causing reputational damage amongst the user base. Let’s look at what’s behind this from an RF perspective and why, devices that connect today, might not connect tomorrow.

The problem – RF congestion and the rising noise floor

RF congestion refers to the overcrowding of radio frequencies used for wireless communications. Every wireless device operates on a specific segment of the radio frequency (RF) spectrum. Wireless technologies utilising popular interoperable protocols like Wi-Fi, and Bluetooth share a limited range of operational frequencies in the unlicenced spectrum allocation. As the number of devices using the same frequency band grows, interference increases, leading to a congested RF environment, and a rising noise floor.

When this occurs, devices experience reduced performance at distance, with lower signal-to-noise ratio, higher data error rates, and potentially complete loss of connectivity, resulting in dropouts.

Why is RF congestion a growing problem?

Essentially it’s down to an explosion in the number of connected devices. According to estimates, there could be 41 billion IoT devices in use by 2030*. Most of these devices operate in unlicensed frequency bands including 2.4GHz and 5GHz, which are already congested. As more devices share the same bands, interference increases.

Also, factor in the following, and it’s easy to see why there’s a problem that’s only going to grow:

Increased demand for bandwidth-heavy applications

From 4k video streaming, to AR and VR applications, these high bandwidth activities further strain the wireless channel capacity. More uses and applications demanding bandwidth simultaneously result in even greater congestion.

Limited RF spectrum

Although the electromagnetic spectrum is vast, only a relatively small range of frequencies are suitable for communication for many applications, and many are regulated by governments differently per region. This leaves a smaller proportion for wireless communications, resulting in popular international frequency bands such as 2.4GHz and 5GHz being particularly crowded. As demand grows, the available frequencies become increasingly saturated.

Poor performance in high-density environments

Multiple devices operating in the same area can interfere with each other, causing packet collisions and requiring retransmissions, and therefore slowing down performance. This is why the effects of congestion are particularly pronounced in high-density environments. Ever experienced problems with your Bluetooth connections at a sports game or at a concert? This is why.

IoT and the “noise floor”

The noise floor refers to the level of ambient RF signals present in an environment. A higher noise floor means that wireless devices must transmit stronger signals to be heard above the noise. However, with regulatory limits on transmit power, this is often not an option. As the number of connected devices grows, the noise floor increases, demanding ever stronger signals, which poses a problem for devices with limited power budgets, such as wearables and other IoT devices.

Wearables and the rising noise floor – a perfect storm

Ever tried to have a conversation in an increasingly crowded restaurant where everyone is shouting over each other to be heard? Similarly, in the wireless world each additional device makes it harder for all devices to maintain a reliable wireless connection. This is particularly problematic for wearable devices, for several reasons:

• The effects of body blocking and detuning often max out the link budget as it is – particularly in non-line-of-sight scenarios
• Increasing the power to max to compensate isn’t an option
• Size limitations impact the antenna’s efficiency
  

BodyWave™ antennas – future-proof wireless connections

In the face of this increasing threat to wireless reliability, an antenna delivering greater immunity to detuning, increased radiation efficiency, and addressing the issue of body blocking, to achieve 10-20 dB improvement in link budget for non-line-of-sight scenarios, should be considered for any wireless device placed on challenging platforms such as

• on the body (in the case of wireless wearables)
• on metal (in the case of IIoT and automotive applications)

This will help to achieve the goal of future-proofing wireless connections in two ways:

Increasing noise floor margin

A 10-20 dB improvement effectively raises the signal above the noise floor providing:

• More reliable connections
• Better data throughput
• Reduced power consumption
• Fewer retransmissions

Making higher frequencies reliable

Congestion in lower bandwidths is pushing manufacturers to consider higher frequencies. However, higher frequencies are more susceptible to the effects of body blocking, unless a solution is put in place to address this issue. BodyWave™ antennas are the only antennas designed specifically to address the negative effects of body blocking by generative a wave that flows efficiently around the body. Ultra-wideband (UWB) in particular offers several advantages:

• Less congested spectrum
• High precision ranging
• More available bandwidth
  

The solution - what device manufacturers should consider today, to ensure continued wireless reliability in the future

• Optimise their wireless system
• Invest in more effective antennas
• Consider higher frequencies, such as UWB
• Plan for and test the performance of devices in non-line-of-sight scenarios
• Build in link margin for future congestion
  

* Source: IOT Analytics Global IOT market forecast