When we need to share something from our digital devices like mobile and PC, the technology that first comes to our mind is the Bluetooth. It can be used to share any kind of files like audio, video and text as well. Today all mobile phones and computers have this technology. In this little article we will look into the depths of Bluetooth technology.  Before getting into Bluetooth I would like to define a term called the “Protocol”. It is nothing but something that gives rules, regulations and standards for two devices to communicate which are either wired or wireless. Bluetooth was intended to replace a wired (RS232) channel that is why called as wireless technology. It was developed by a Swedish telecom provider Ericsson in 1994. It uses an unlicensed band (ISM band) Industry, Scientific and Medicine of 2.4 GHz to 2.485 GHz. The IEEE standard for Bluetooth is IEEE 802.15.1 and it is controlled by Bluetooth Special Interest Group (SIG) which has 25,000 members from various fields like telecommunication, consumer electronics, Internet of Things (IoT). Let’s take a look at its class, profiles that define and manage the communication.

Bluetooth classes:

The important and primary parameters of wireless communication are range and power. Bluetooth provides different range of coverage and power and is defined by Bluetooth classes.  There are three different classes present in Bluetooth. Table below tell you the range and operating power of each class.

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Class 1 provides you to communicate over long distance of 100 meters which can be extended more by installing suitable repeaters. Most applications of this class 1 in industries and distributed sensor networks. The only disadvantage is its power consumption which makes it to not suitable for portable devices.

All our electronics devices which support Bluetooth fall in this class 2 category. Because it consumes less power of 4 dbm and it suits for portable devices and electronic gadgets. With this small amount of operating power it covers a range of 10m which is enough for small applications like file sharing, Bluetooth audio.

Class 3 is not applicable for communication more than 1 meter. But it consumes very less power that above two classes. On board communication and very short range communications equip this class of Bluetooth.

Bluetooth Profiles:

To understand what is a Bluetooth profile? First we discuss some of the applications. Bluetooth has been used by everyone in a daily basis for sharing something like audio or video files.  So it supports audio and video transmission. Bluetooth headset is a well-known application which enables us to receive call, hold, call conference and even it can be used to hear songs.  Televisions became smart which has begun to use mobile phones as remote control. Bluetooth plays the role of a mediator (communicator). So it supports some remote control applications. Some recent applications of Bluetooth are smart watches, Remote Patient Monitoring (RPM), Internet of Things (IoT), Wireless Sensor Networks (WSN).  Profiles or Bluetooth stack is an application, based on protocols that enables two devices to communicate. For example A2DP (Advanced Audio Distribution Profile) permits to transfer high quality audio between two devices. So to transfer audio between devices, they must agree the conditions defined by this A2DP profile. Some application oriented profiles in Bluetooth which we use in our everyday life are.

HSP (HeadSet Profile):

This profile allows a full duplex (Bi-directional) communication between a headset and a mobile phone. Two Bluetooth devices must be equipped with this profile. Some of the controls to be mentioned are

  1. Call attend
  2. Dialling the recent call
  3. Redialing
  4. Holding
  5. Conference
  6. Mono audio (Music)
  7. Controls and warnings (Voice commands)

A2DP (Advanced Audio Distribution Profile):

This profile provides a way to transmit a high quality (without loss) stereo audio between two devices like mobile and head phones. Bluetooth speaker is the best example of stereo audio transfer. Both devices must agree the conditions of A2DP. Some controls are

  1. Play
  2. Pause
  3. Back
  4. Forward
  5. Volume control

AVRCP (Audio Video Remote Control Profile):

Remote control applications like Television and home automation makes use of this profile. Whenever Bluetooth applied in control applications it should have this profile. Some controls are

  1. ON
  2. OFF
  3. Channel selecting
  4. All home automation controls

Wireless monitoring profiles: 

Patient monitoring employs Bluetooth as a communication medium. Some notified profiles are

  1. Heart rate profile – Monitors and transmits heart rate
  2. Pressure monitor profile – Monitors and transmits pressure
  3. Glucose monitor profile – Monitors and transmits glucose level
  4. Blood pressure profile – Monitors and transmits blood pressure

These profiles are intended to work with patient monitoring environment and provide some controls for transmission.

So finally, a profile or stack means it is an application oriented protocols (controls) that must be agreed or present in between two devices to make that application to work.

We had a look at some basics of Bluetooth terminologies which makes you to understand what Bluetooth is and how it works. If you are planning to deploy Bluetooth in your application first consider the range (class) and be sure that the needed profile is present in that Bluetooth module.

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