Can Bluetooth Go Through Walls?

The first thought that came to mind when I got Britz Bluetooth speaker was to check whether the Bluetooth signal can go through walls. Guess what I did. I stepped out of the room at the thought of that to connect to the speaker. With two concrete walls between us, my phone was able to connect and even play a song.

With such a small device, it proved to me that Bluetooth signal can go through walls. However, the signal strength is a major concern here. That is dependent on the Bluetooth range and other factors such as radio frequency interferences. Just as you can hear someone speak in the next room at varying clarity and volume depending on the thickness of the walls, so is the Bluetooth signal strength.

The device’s Bluetooth range is one key thing you have to be concerned about. In my case, I could stand at a distance from the two walls and still be able to connect to the speaker. But how far could that be to still stay connected?

From the horse’s own mouth, Bluetooth devices can range from more than a kilometre down to less than a meter. But developers’ design requirements dictate the range used in devices. Hence knowing the ranges will put you in a comfortable position to go for the right Bluetooth device.

Bluetooth Ranges And Factors That Affect It

The version of your Bluetooth is the first thing to check to know its capability of going through walls. While several factors may affect its resulting range, the Bluetooth version provides you with the maximum range you can achieve.

Can bluetooth signal go through walls

As you can see, there are tradeoffs to having Bluetooth of longer range. The latest Bluetooth version 5.0, however, has been developed to double its speed, improve on broadcast messaging capacity and increase the range about 4 times.

While the latest version offers several benefits to the previous versions, you can’t be sure of getting the exact design range. Your Bluetooth overall range will still be determined by factors such as:

Bluetooth Spectrum Band

Bluetooth uses radio spectrum of frequency ranging from 30Hz to 300 GHz depending on the device’s design purpose. The lower the frequency of the radio spectrum the farther it can go that is the longer its range. However, that comes with data transfer trade-off.

Spectrum band that provides a good balance of range and data transfer speed is what Bluetooth uses – 2400 to 2483.5 MHz which is available around the globe. Apparently, all the Bluetooth versions use the same band range but their Bluetooth range differs. So what’s makes the difference then?

Losses in Bluetooth Path

This is also referred to as path attenuation which is basically the depletion of signal strength over a distance in an environment. In other words, things that come in between Bluetooth devices affects the range of the radio signal.

In an open space, air can cause Bluetooth signal strength to vary but you can have as high as a hundred meters or even more depending on the design capacity. You can’t expect to have such a high range with denser attenuators such as wood, glass, metal and concrete walls.

However, there are instances where Bluetooth of Low Energy modules have achieved 75m and 90m line of sight connection with walls and pillars in between the devices. That’s possible with the adaptive feature hopping implemented on the latest versions of the Bluetooth technology.

Antenna Design

How well electrical energy is converted into radio waves from transmitter to a receiver contributes to the Bluetooth range. It affects how distant Bluetooth devices can be from each other and still communicate. If the antenna design doesn’t foster signal strength, the Bluetooth range wouldn’t go over a long distance or through walls.

Antenna efficiency has a major impact on Bluetooth range. The reason is that its ability to focus the direction of energy must seamlessly fit with location, packaging size and design style. So you don’t have to go in for any antenna. You have to be concerned about its design if you’re expecting to have stronger Bluetooth signals that could go through walls.

Transmit Power

While you want to have a longer Bluetooth range, you also have to bear in mind the power that the device consumes. Range and transmit power go together. The higher the transmit power, the farther the signal can travel even through walls which implies longer Bluetooth range.

However, this will come at a price of higher power consumption of your Bluetooth device. So if you want stronger signals and have no concern for power then you can consider devices with higher transmit power.

The sensitivity of the Receiver

Bluetooth signal can be received at the other side of a concrete wall depending on how sensitive the receiving device is. Bluetooth devices normally have a minimum receiver sensitivity of -70dBm to -82dBm. This is controlled by the technique used to send data over its radio frequency.

But there are cases where a Bluetooth device can have a sensitivity of -103dBm. Therefore checking out this property is essential if you want to your device to detect Bluetooth signal over a wall.

Most of the factors I’ve discussed here are decisions that are usually made by manufacturers of the Bluetooth device. What do you do then if the fate of your Bluetooth device is already decided? Let’s see how you can improve then range then.

How To Improve Your Bluetooth Range To Go Through Walls

Upgrade Devices to The Same Bluetooth Version

If your Bluetooth devices have different versions, then you can’t expect them to communicate in the same range. They may have different receiver sensitivities. For example, an older Bluetooth device with the power to transmit over 33ft range will limit that with a capacity of 1000ft.

You can boost the Bluetooth range of your older device by upgrading it to the latest version. This will be plausible if the hardware supports upgrade. When you achieve that then you can have a substantial improvement in your connectivity.

Bluetooth Signal Repeater

These devices are used as an intermediary between two Bluetooth devices which are of unequal range.  You use the repeater by placing it in between the two devices keeping it within the range of the shorter or weaker one to provide some sort of signal boost.

For instance, a 33ft Bluetooth range device could use a repeater to broadcast its signal to be able to connect with a 1000ft device. This idea of repeaters seems nebulous in practical use for consumer Bluetooth device. However, this solution appears to be in adoption for commercial grade Bluetooth devices and are expensive.

Bluetooth Signal Extender

Bluetooth signal extender may sound pretty much the same as Bluetooth signal repeater. But they’re different devices which work in distinct ways to achieve a common purpose-improve Bluetooth range. You’ll come across them being used sometimes interchangeably but they’re not the same by way of how they function.

Bluetooth signal repeater connects to your existing Bluetooth device of weaker range and relays it to a wider area. Bluetooth signal extender also connects to an existing Bluetooth network through a wired link and then broadcasts the signal to another region of space.

Bluetooth extenders can be differentiated into four definite classes in terms of range and power consumption.

  • Class 1 Bluetooth Range Extenders: They work within the range of hundred meters and consumes around hundred milliwatts of power.
  • Class 2 Bluetooth Device Extenders: Ten (10) meters of Bluetooth range and 2.5 milliwatts of power consumption.
  • Class 3 Bluetooth Extenders: Less than ten (10) meters range and consume one (1) milliwatt of power.
  • Class 4  Devices: It’s the least performing extender considering the range. Has Bluetooth range and power consumption of 0.5 meters and 0.5 milliwatts respectively.

Create a Network of Bluetooth Connected Devices

In a research paper titled “An expanded Bluetooth network – a solution to the short-range Bluetooth communication“, the author proposed a network of devices that include laptops, set-top devices and mobile phones to enable devices to connect with each other within and out of the Bluetooth range.

It shows you the topology of the connection and how you can utilize this proposed network to improve your Bluetooth range.

Final Thoughts

The Bluetooth technology is not a short-range signal as perceived by many. It’s boldly emphasized to be able to reach a distance of 1km depending on how your device manufacturer specifies its requirement.

What this implies is that Bluetooth signal can go through walls if designed to its maximum range. However, this is not the case for most customer-use Bluetooth devices. If you’re handicapped by this number of factors that affect your Bluetooth range, then you can try out the methods shared in this article to improve it.

I hope the article has been helpful to you.

2 thoughts on “Can Bluetooth Go Through Walls?”

  1. I had the same question too with my bluetooth devices. I learned that it can go through walls but if I am going upstairs or down in the basement then I will lose the connection. I have no idea that I can lose the signal in the open space, that is interesting. I will make sure to update all my devices for a better pair. Thanks for sharing such an informative post! 

    Reply
    • Hi Nuttanee, 

      Thanks for sharing your experience. I think what you can start with is checking on the Bluetooth versions of the devices. Knowing that will give you a fair idea of how distant you can be from each other. 

      Reply

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