FIELD OF INVENTION
The invention generally relates to wireless communication and particularly to method and system for audio streaming to multiple devices over Bluetooth.
BACKGROUND
Advanced infotainment systems are equipped with connectivity options like Bluetooth and Wi-Fi, interactive voice recognition services, live media streaming service and smart technology for mobile integration. Media streaming is an important part of infotainment. With technological enhancements and innovations, media sharing and streaming occurs seamlessly through different interfaces like Ethernet AVB, WIFI/UPnP, mirroring etc. However, Bluetooth interface plays an integral role in infotainment systems with support of profiles like HFP, PBAP, MAP, SPP, A2DP etc. However, as per audio streaming is concerned, Bluetooth lacks streaming to multiple devices till its version 4.1. Accordingly, there is a need to implement audio streaming feature over Bluetooth interface to stream audio to multiple receiver devices simultaneously from a single Bluetooth source/host radio. This can come with various use case development like directional audio system based on bluetooth.
The present invention is directed to overcoming one or more of the problems as set forth above.
SUMMARY OF THE INVENTION

invention discloses modifications in Audio/Video distribution Transport protocol (AVDTP) of Bluetooth host software stack to support audio streaming to multiple receiver devices. According to an embodiment, the receiver devices may receive same or different audio streams from the single Bluetooth source device.
BRIEF DESCRIPTION OF DRAWINGS
Other objects, features, and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:
Figure 1 illustrates a BlueZ, a Bluetooth stack protocol architecture, according to an exemplary
embodiment of the invention;
Figure 2 illustrates an Advanced Audio Distribution Profile (A2DP) architecture, according to
an exemplary embodiment of the invention;
Figure 3 illustrates a process for a connection establishment of AVDTP, according to an
exemplary embodiment of the invention; and
Figure 4 illustrates implementation of an audio streaming feature over Bluetooth interface for
streaming audio to three Bluetooth devices simultaneously, according to an exemplary
embodiment of the invention.
DETAILED DESCRIPTION OF DRAWINGS
The following description with reference to the accompanying drawings is provided to assist

the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
According to embodiments of the invention, a system and method for streaming audio to multiple receiver devices simultaneously over a single Bluetooth source/host radio is disclosed.
Figure 1 illustrates a BlueZ, a Bluetooth stack protocol architecture, according to an exemplary embodiment of the invention. BlueZ Core in Figure 1 is main host stack software. The BlueZ
core communicates with the Bluetooth (BT) hardware using HC1 protocol to execute general
i
control of the hardware such as, but not limited to, reading HW features, versions, initiating scanning states, parsing out scanning results and managing connections. According to an embodiment, in context of audio, BlueZ may be responsible for establishing transport links. According to another embodiment, Pulseaudio may be required to stream over the established transport links.
Figure 2 illustrates an Advanced Audio Distribution Profile (A2DP) architecture, according to an exemplary embodiment of the invention. Figure 2 show different layers through which A2DP connections take place. Audio/Video distribution protocol (AVDTP) may be responsible for stream connection establishment and signalling between two devices. According to an embodiment, the AVDTP may store information about Stream End Point

in order to negotiate a stream. According to another embodiment, signalling or connection establishment between two devices may be performed by a series of commands specific to AVDTP transport.
Figure 3 illustrates a process for a connection establishment of AVDTP, according to an exemplary embodiment of the invention. The establishment of the AVDTP connection starts with stream endpoint discovery where the INT/initiator initiates for a list of available SEPs. Get capabilities and Stream configuration are responsible for checking the capabilities and configuration for stream establishment. With stream establishment, streaming channel gets created for carrying media streams. As illustrated in Figure 1, Pulseaudio interacts with Bluez stack through Dbus and gathers all required parameters for streaming.
Figure 4 illustrates an implementation of an audio streaming feature over Bluetooth interface for streaming audio to three Bluetooth devices simultaneously, according to an exemplary embodiment of the invention. The bandwidth may be sufficient for audio streaming as two devices connected in hands free profile (HFP) and A2DP are able to stream audio. Code changes have been made in user space itself, especially in AVDTP layer to support multiple sessions and streams. Hence, each of the three Bluetooth devices have their own session and stream reference. According to an embodiment, the stream reference may include parameters for setting up stream and streaming media.
As connection is established consecutively, Pulseaudio creates three independent cards for respective devices. Using application like Gstreamer, audio may be streamed to all the three devices and all the three devices (sinks) may be combined to create a common sink to have

In the drawings and specification there has been set forth preferred embodiments of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts, as well as in the substitution of equivalents, are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention. ■
Throughout the various contexts described in this disclosure, the embodiments of the invention further encompass computer apparatus, computing systems and machine-readable media configured to carry out the foregoing systems and methods. In addition to an embodiment consisting of specifically designed integrated circuits or other electronics, the present invention may be conveniently implemented using a conventional general purpose or a specialized digital computer or microprocessor programmed according to the teachings of the present disclosure, as will be apparent to those skilled in the computer art.
Appropriate software coding can readily be prepared by skilled programmers based on the teachings of the present disclosure, as will be apparent to those skilled in the software art. The invention may also be implemented by the preparation of application specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be readily apparent to those skilled in the art.