Bluetooth: consumption for different states

Here we present results of measurements regarding data communication using Bluetooth.

 

Experiment details

 

Description:

Measurements of power consumption of Bluetooth in different states.

Place:

Indoor, room size 20 m2.

Technology used:

Bluetooth 2.0 +EDR.

Number of tests:

30 tests for each state.

Notes:

During the measurements the other air interfaces (WLAN and Cellular) are switched off. The phones are standing at 15 cm from each other.

 

 

In the figure below, the power consumption for different Bluetooth states is reported.

Power consumption of the phone when Bluetooth in different states
  • BT off
    This is the power consumption of the phone with Bluetooth off. Since all the other air interfaces are off and the backlight of the display as well, this represents the minimum consumption of the phone when is not doing anything.
  • BT on
    We have measured the power consumption of the phone with only Bluetooth on and everything else inactive.
  • BT connected+idle
    This is the power consumption of a phone connected to another one but not sending nor receiving data.
  • BT discovery
    This is the power consumption when a mobile phone is performing a device discovery. This procedure can take a longer time according to the number of the devices in the range, but the power levels are the same. Therefore the energy depends on the duration of the discovery.
  • BT Receiving
    This is the power consumption of a phone receiving data using an RFCOMM protocol.
  • BT Sending
    This is the power consumption of a phone sending data using an RFCOMM protocol.

 

In Figure below values for power consumption of the phone when Bluetooth is switched off and when it is turned on and in idle mode are shown. By comparing the two values, is possible to note that having Bluetooth on will increase the power consumption by only 3 mW. This goes against the common idea that Bluetooth has a very high power consumption when turned on.

Power consumption of the phone when Bluetooth is on but in idle mode and when it is switched off.

Parametrized model

Energy = P_action * Duration

 

ActionP_action [mW]

BT off (phone idle)

12.04

BT on

14.82

BT connected not tx nor rx

66.62

BT device discovery

223.03

BT rx

425.38

BT tx

432.35

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Last update:20-07-2011