Bluetooth

Bluetooth is a wireless technology standard for exchanging data over short distances.

Bluetooth Profiles

There are hundreds of Bluetooth profiles available but only following are the profiles which we use in the NextGen automobile infotainment system testing:

1.LMP (Link Management Protocol)

2.SDP (Service Discovery Protocol)

3.L2CAP (Logical Link Control and Application Protocol)

4.RFCOMM串口仿真协议

5.HFP (Hands-Free Profile)

6.OBEX (Object Exchange Protocol)

7.MAP (Message Access Profile)

8.PBAP (Phonebook Access Profile)

9.A2DP (Advance Audio Distribution Profile)

10.AVRCP (Audio Video Remote Control Profile)

Baseband:

Baseband is a physical layer of Bluetooth. It manages physical channels and links apart from other services like error connection, data whitening, hop selection and Bluetooth security. The Baseband layer lies on the top of the Bluetooth radio layer in the Bluetooth stack. The Baseband protocol is implemented as Link Controller, which works with the link manager for carrying out link level routines like link connection and power control. The Baseband also manages asynchronous and synchronous links, handles packets and does paging and inquiry to access and inquire Bluetooth devices in the area.

LMP (Link Management Protocol)

LMP controls and negotiates all aspects of the operation of Bluetooth connection between two devices which is setup and control of logical transports and logical links and also for control of physical links. LMP is also used to communicate between Link Managers of the two devices connected by ACL (Asynchronous Connection Logic) logical transport.

LMP messages are exchanged over the ACL-C logic link that has higher priority than other packets of traffic.

SDP (Service Discovery Protocol)

SDP is used to discover services on a remote device. It sends the service inquiries to and from the Bluetooth enabled devices. It inquires about the services which are available on the Bluetooth

device to which it connects.

L2CAP (Logical Link Control and Application Protocol)

L2CAP layer provides the logical channels which connect to L2CAP logical links supported by ACL logical transport. L2CAP supports higher level protocols and applications to transmit and receive upper layer data up to 64kb.

RFCOMM

It is used for providing serial data transfer. RFCOMM connects to the lower layers of the Bluetooth protocol stacks through the L2CAP layer. It supports 60 simultaneous connections between two Bluetooth devices.

HFP (Hands-Free Profile)

HFP is used to provide hands-free connection between Master and Slave for calls. It uses SCO packets. It defines two roles:

1.AG (Audio Gateway): This is the device that is the gateway of audio, both for input and

output, typically a mobile phone.

2.HF (Hands-Free unit): This is the device ac ting as audio gateway’s remote audio input

and output mechanism. It also provides some remote control means.

OBEX (Object Exchange Protocol)

OBEX is a transfer protocol that defines data objects and communication protocol two devices can use to exchange those objects. OBEX works for File Transfer, PBAP, MAP etc.

MAP (Message Access Profile 短信读取协议)

MAP is used to exchange messages between Master and Slave to 3rd Party. It covers:

1.Notifying messages.

2.Browsing the messages.

3.Uploading messages.

4.Deleting messages.

5.Sending messages.

PBAP (Phonebook Access Profile)

PBAP is a procedure and protocols to exchange the phonebook and call history between the devices. It works with OBEX.

A2DP (Advance Audio Distribution Profile)

A2DP is used to stream high quality mono or stereo audio from media source to a sink.

Source (SRC): Source is a device which has digital audio streams or files.

Sink (SNK): Sink is a device which streams the digital audio via Bluetooth.

AVRCP (Audio Video Remote Control Profile)

AVRCP is used to provide a standard interface to control hi-fi equipment to allow a single remote