IoT における Bluetooth の通信範囲に影響を与える要因は何ですか

Bluetooth低エネルギー (なりました) 現在IoTの世界で広く議論されています. It is safe to assume that most of us have a good grasp of what Bluetooth is and how it practically works. Like all wireless technologies, BLE is better suited for certain applications than others. But what exactly determines how far these invisible threads of connectivity can stretch? If you’re considering using Bluetooth or BLE in IoT, here is a list of the primary factors influencing the Bluetooth range along with some methods to extend it.

What is Bluetooth range

Before discussing the factors, it would be useful to define what we mean by “範囲” in Bluetooth technology. Bluetooth range is the maximum distance at which two Bluetooth-enabled devices can exchange data reliably. This often translates to how far your Bluetooth headphones can be from a phone or how spread out your Bluetooth sensors from a gateway in the IoT world.

The Bluetooth SIG says the Bluetooth range is:

From more than a kilometer to less than a meter.

あれは, the practical, reliable range between Bluetooth devices is over one kilometer down to less than a meter.

Why Bluetooth range is short

Bluetooth’s short range isn’t a bug, it’s a feature. It uses the 2.4 GHz band with low transmission power to save battery. This limits its range by design. Bluetooth is meant for personal area networks, connecting devices right around you. The tech uses frequency-hopping spread spectrum (FHSS), which is cool but also limits range.

When considering the characteristics of a radio-based network like Bluetooth, three key factors come into play:

• 範囲
• データ転送速度
• 消費電力

しかしながら, it’s challenging to prioritize all three because the laws of physics impose clear limitations. 例えば, while Bluetooth can achieve high data transfer speeds, this often comes with increased power consumption and a reduced range.

We primarily deal with two types of Bluetooth: Bluetooth クラシックと Bluetooth Low Energy (なりました). Bluetooth Classic transmits in all directions at a pretty high data rate. It typically has about 10m of range, while BLE can reach up to 100m by transmitting in short bursts at higher power but lower data rates.

ブルートゥース 5 and Long Range Mode

に 2016, ブルートゥース 5.0 お披露目されました, building on version 4.2 but doubling its transmission speed. The new version is better suited for indoor positioning and IoT communications. LE Coded PHY is the long-range mode of Bluetooth that was introduced in Bluetooth 5.0. It basically extends the range of regular BLE devices from 30-100 ft to up to a kilometer.

Bluetooth® Long Range mode increases range without raising output power, 使用して “コード化された PHY” with Forward Error-correcting Codes (FEC). This trades off with data rate, reducing it to 500 kbps or 125 kbps.

The LE Coded PHY offers two data rates:

• S2: Each bit uses two symbols, halving data rate to 500kbps (half of 1M). Range doubles compared to LE 1M PHY.
• S8: Each bit uses eight symbols, reducing data rate to 125kbps (1M divided by 8). Range quadruples compared to LE 1M PHY.

Using coded PHY can achieve up to 1 km range in hilly terrain and several hundred meters in apartment buildings.

Key factors affecting Bluetooth range in IoT

The range of a Bluetooth network is not just defined by a single factor but is rather a total of several factors. These include technical factors, BLE hardware devices, signal transmission environment, compliance, 等々, which define in actuality the basic capability of a Bluetooth network to transmit data across certain distances.

Technical factors

• Transmitter power

Transmit power is perhaps the most straightforward factor affecting range. 簡単に言えば, the higher the transmit power, the further the Bluetooth signal can travel. しかしながら, it’s not as simple as setting the transmission power to maximum.

In IoT applications, particularly those using battery-powered BLE devices, power consumption is a critical concern. Higher transmit power often means faster battery drain.

• 受信感度

While transmit power gets a lot of attention, receiver sensitivity is equally important. A more sensitive receiver can pick up weaker Bluetooth signals, effectively increasing range without additional power consumption. Advancements in chip design have significantly improved receiver sensitivity in recent years.

• Antenna design and placement

Antenna design plays a crucial role in Bluetooth range. The type, サイズ, and orientation of the antenna can significantly impact signal strength and directionality. In compact Bluetooth IoT devices, space constraints often limit antenna options. 通常, external antenna design can have better range results. Our new-coming MKGW7 USB gateway is an excellent example.

• Bluetooth versions and features

の version of Bluetooth used in your IoT devices can significantly impact range. ブルートゥース 5.0, で紹介された 2016, brought major improvements to range capabilities.

Bluetooth 5.0’s Long Range feature, which uses coded PHY, can quadruple the range compared to previous versions. しかしながら, this comes at the cost of reduced data rate. For many IoT applications, this trade-off is well worth it.

環境 factors

The environment in which your BLE devices operate has a massive impact on the Bluetooth range. They will behave differently depending on the environments they are used, from outdoor, 産業用, and office to home. The Bluetooth SIG offers an estimated range calculator through which one can get an estimated range related to certain criteria such as path loss in various environments.

Outdoors, in an open space, you can get a range of up to a few hundred meters. Inside buildings, obstacles like concrete walls, metallic objects, and even noise will limit the transmission range of the radio signal. In normal use, 70 meters is a reliable estimate of the achievable range between two BLE devices indoors.

理想的には, a BLE signal travels in a straight line from the BLE beacon antenna through the atmosphere to the smart receivers. しかしながら, when there is an obstruction between the BLE beacon and the receiving end (NLOS environment), the BLE signal will be blocked during transmission, leading to varying degrees of attenuation depending on the type of obstruction. This attenuation is much stronger than that caused by the atmosphere, thereby further affecting the effective transmission range of BLE devices.

Regulatory and compliance factors

Bluetooth range isn’t just about tech specs – regulations and compliance also shape it. Authorities like the FCC in the US and ETSI in Europe set limits on how strong Bluetooth signals can be and what frequencies they can use. This means that companies manufacturing Bluetooth devices have to abide by these rules which in turn can affect the practical range of the devices. It is intended to operate non-interference with other wireless technologies and co-exist with other users in the radio spectrum.

4 methods to optimize Bluetooth range in IoT

Now that we’ve covered the factors influencing BLE range, let’s look at some strategies to optimize your IoT deployments:

Amplifying the Signal

A direct way to extend Bluetooth range is by increasing transmit power. しかしながら, this approach can significantly reduce battery life and must be balanced against regional regulatory limits, with the U.S. allowing up to +20 dBm and the E.U. それだけ +10 dBm. Despite these challenges, boosting transmitter power is often more efficient than other methods, offering better latency, スループット, and simpler setups, particularly in industrial environments, where a 3dB increase can effectively double the range.

Using Long-Range in Bluetooth 5

ブルートゥース 5 introduced LE Long Range/CODED PHY to extend range without boosting power by employing Forward Error Correction (FEC), which repeats packets 2 または 8 times to improve message reliability over distances. This can enhance range by up to 4 タイムズ, though it reduces throughput and increases power consumption. It’s analogous to repeating words for a distant audience rather than shouting louder.

The S2 and S8 coding schemes offer data rates of 500kbps and 125kbps. For this technique to be effective, both communicating BLE devices must support CODED PHY; さもないと, the benefits may not be realized.

Leveraging a Repeater

Introducing repeaters can extend Bluetooth range by picking up and retransmitting messages. This works best in stationary device networks, where repeater placement can be optimized. しかしながら, this approach can be costly and complex, requiring additional hardware, パワー, とインストール, and introduces security concerns as all devices must trust the repeater. Managing repeaters involves careful placement and configuration, and they may need re-provisioning if replaced.

Utilizing Bluetooth Mesh networking

Bluetoothメッシュ networks significantly extend coverage by leveraging all nodes in a network. In this configuration, each device in the network acts as a relay point. They receive data packets, determine if they’re the intended recipient, and if not, forward them to nearby devices. Battery-powered nodes can save energy through the Low Power Node feature and “友人” モード, which allows them to sleep longer and check in intermittently. This is ideal for large areas or buildings where multiple distributed anchors and gateways connect Bluetooth devices and cloud servers. The multi-point to multi-point BLE mesh technology has substantially enhanced Bluetooth’s networking capabilities, offering high reliability and effective prevention of single points of failure.

For in-depth information and guidance on integrating MOKO’s range of BLE tags, アンカー, and gateways into tailored BLE mesh solutions, we encourage you to talk to our Bluetooth experts.

How does MOKO’s Bluetooth devices perform

Optimizing Bluetooth range isn’t just about reaching further – it’s about creating smarter, more efficient IoT networks that deliver real value. Whether you’re tracking assets in a large 倉庫, creating a responsive smart home system, or monitoring temperature conditions in a cold chain, choosing reliable BLE devices is key to your success.

MOKO SMART is dedicated to offering advanced and reliable Bluetooth devices that will make IoT projects possible. From our wide range of BLEビーコン to our efficient gateways and smart sensors, we have a complete BLE product chain to cater to your needs.