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Bluetooth 5 range and speed enhancement

Bluetooth beacon strength is constrained and can be affected by limits placed on the transmitter power to preserve battery life. Usually, a line of sight is needed for optimal beacon range and signal strength. Shown below is the signal strength to distance curve for typical line-of-sight Bluetooth 4.0 communication.

Beacon strength is limited. Often a manufacturer limits the Tx power of a beacon to preserve battery life. As one move from the beacon, the signal strength drops as expected. Typically a 30-foot range is a usable beacon distance (Bluetooth 4.0)

Bluetooth also has different power levels, ranges, and transmission power based on a classification for each device:

Bluetooth 5 has improved the range as well as data rate beyond legacy Bluetooth limits. A new radio PHY is available with Bluetooth 5 called LE2M. This doubles the raw data rate of Bluetooth from 1M symbol/second to 2M symbols/second. To transfer an equal amount of data on Bluetooth 5 as opposed to Bluetooth 4, less time will be needed for transmission. This is particularly relevant for IoT devices that operate on coin cells. The new PHY also increases the power from +10 dBm to +20 dBm, allowing for greater range.

With respect to range, Bluetooth 5 has another optional PHY for extended range transmission in BLE. This auxiliary PHY is labeled LE coded. This PHY still uses the 1M symbol/second rate as in Bluetooth 4.0, but reduces lower packet coding of 125 Kb/s or 500 Kb/s and increases the transmission power by +20dBm. This has the effect of increasing the range by 4x over Bluetooth 4.0 and having better penetration within buildings. The LE coded PHY does increase power consumption for the benefit of increased range.

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