WO2008015591A1

WO2008015591A1 - Method and system for establihing and controlling communication between two communication devices

Info

Publication number: WO2008015591A1
Application number: PCT/IB2007/052593
Authority: WO
Inventors: Francesco Gallo; Heribert Baldus; Karin Klabunde
Original assignee: Philips Intellectual Property and Standards GmbH; Koninklijke Philips Electronics NV
Current assignee: Philips Intellectual Property and Standards GmbH; Koninklijke Philips NV
Priority date: 2006-07-31
Filing date: 2007-07-03
Publication date: 2008-02-07
Anticipated expiration: 2009-01-31

Abstract

A method of establishing and controlling communication between a first communication device (3) and a second communication device (2) and a system in accordance with the inventive method is disclosed. The first communication device (3) comprises a first short-range wireless communication interface (7) and a first body-coupled communication interface (6). The second communication device (2) comprises a second short-range wireless communication interface (5) and a second body-coupled communication interface (4). The first communication device (3) is configured to send signaling data by its first body-coupled communication interface (6) to the second body-coupled communication interface (4) of the second communication device (2) in order to establish a short-range wireless communication link (13) between the two short-range communication wireless interfaces (5, 7) of the two communication devices (2, 3).

Description

METHOD AND SYSTEM FOR ESTABLIHING AND CONTROLLING COMMUNICATION BETWEEN TWO COMMUNICATION DEVICES

FIELD OF THE INVENTION

The invention relates to a method of establishing and controlling communication between two communication devices and to a system for exchanging data.

BACKGROUND OF THE INVENTION

As is known, mobile phones can be used in combination with headsets. The headset and the mobile phone may be connected wirelessly, for instance using Bluetooth. In this case, both, the mobile phone and the headset have each a Bluetooth communication interface. Bluetooth comprises a so-called "headset profile" supporting communication between the headset and the mobile phone. When establishing a connection between the headset and the mobile phone, the asynchronous connectionless (ACL) link is used for signaling messages for establishing and controlling the communication link of an audio- stream between the mobile phone and the headset. The audio-stream itself is transmitted using the synchronous connection oriented (SCO) link.

An active Bluetooth communication link, however, consumes relatively much electric power, compromising the stand-by time of the mobile phone.

Bluetooth also supports certain low power modes for the ACL-link. When in the low power mode, then the devices are asleep most of the time, waking up periodically only at time intervals of a few seconds when the ACL-link is needed for transmitting the signaling messages. Thus, a relatively long time period is needed when establishing the SCO-link for the audio-stream. This is especially bothersome when receiving a telephone call.

In addition to radio communication, it is known to use the human body for transmitting data. Published U.S. application for patent US 2004/0152440 A2 discloses a portable terminal, which transmits to and receives from a displaying apparatus instrument identification information through a person's body when the person touches body communication sections of the portable device and the displaying apparatus. After that, communication between the portable device and the displaying apparatus is established through communication means other than the human body, for instance, through radiation, Bluetooth, wireless LAN, wired LAN, or the Internet.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide a method of establishing and controlling communication between two communication devices, which method consumes relatively little electrical energy and is relatively fast.

Another object of the invention is to provide a corresponding system.

The object of the invention is achieved by means of a method of establishing and controlling communication between two communication devices, the method comprising the steps of: transmitting signaling data from a first communication device to a second communication device by means of a body-coupled communication link in order to establish a communication between the two communication devices; and operating the communication between the two communication devices by means of a short-range wireless communication link between the two communication devices.

According to the inventive method, the signaling data are exchanged between the two communication devices utilizing the body-coupled communication link. The two communication devices are, for instance, a headset and an audio gateway, for instance, in a mobile phone. Body-coupled communication, which is also referred to as near-field intra- body communication as is known from the published U.S. application for patent US 2004/0152440 A2 mentioned in the introduction, is a wireless technology that allows electronic devices on and near the human body to exchange information through near- field electrostatic coupling. Information is transmitted by modulating electric fields and electrostatic (capacitive) coupling currents to the human body. The body conducts this current, which is in the range of a few ten pico amps to body mounted receivers. The environment (the air and ground) provides a return path for the transmitted signal.

The body-coupled link is used for the transmission of the signaling data. Signaling data are used in telecommunication for establishing and controlling the communication link for the user information transfer, for which transfer the short-range wireless communication link is used. Signaling data are not just used for an identification, as it is used for establishing the connection between the portable terminal and the displaying apparatus instrument of published U.S. application for patent US 2004/0152440 A2. Signaling data are used, besides for establishing the short-range wireless communication link, for maintaining the short-range wireless communication link while the user information transfer is carried out. As a result, contrary to the link known from US 2004/0152440 A2 and needed for the identification information, which is not needed after the communication between the portable device and the displaying apparatus has been established, the body- coupled link according to the inventive method is maintained while the short-range wireless communication link is active.

Since the body-coupled communication link consumes relatively little power, this link can basically be active all the time, avoiding a wake-up period as is common when using the ACL-link for the signaling data. When the connection between the two communication devices is established, the signaling data are still used to control, i.e. maintain and end the communication. Then, the signaling data may be transmitted via the body-coupled communication or the short-range wireless communication link.

The signaling data may be used to establish communication between the first communication device and a telecommunication or a data network by means of a wireless communication link. The first communication device, which may be a telephone or a computer, may be used to receive a data-stream or an audio-stream from a telecommunication or a data network, such as the Internet, and/or may be used to send such an audio- or data-stream over the telecommunication or the data network to a further device. Then, the communication link, which may especially be a wireless communication link, may be established and controlled utilizing the signaling data.

In one embodiment of the inventive method, the first communication device is a mobile phone and the second communication device is a headset, so that, when the mobile phone receives an incoming or initiates an outgoing telephone call, the mobile phone and the headset exchange the signaling data by means of the body-coupled communication link in order to establish an audio-stream between the mobile phone and the headset utilizing the short-range wireless communication link. During a telephone call, the mobile phone receives and sends an audio-stream. The received audio-stream has to be forwarded to a loudspeaker of the headset, and the audio-stream sent by the mobile phone is generated using a microphone of the headset. Thus, the audio-stream between the headset and the mobile phone must be established and maintained during the telephone call. This is achieved by the signaling data which are preferably transmitted from the mobile phone to the headset during the telephone call utilizing the body-coupled communication link. However, signaling data may also be transmitted via a short-range wireless communication link during the telephone call. After the telephone call, the signaling link is switched from a wireless communication link to a body-coupled communication link again. Both possibilities result in a substantial saving of electrical energy and in turn a longer battery life.

The signaling messages (signaling data), which comprise, for instance, commands and events to establish, transfer, and disconnect the short-range wireless communication link, are sent before, after, and during the transmission of the audio-stream. The signaling data may also be used to control the audio-stream itself and several features of the headset, especially if the headset is a Bluetooth headset.

If no audio-stream is transmitted between the headset and the mobile phone, in general, if no data transfer between the two communication devices is needed, then the short- range wireless communication interfaces of the wireless devices can be turned off completely.

The body-coupled communication link is not used for the audio-stream. When the mobile phone receives an incoming telephone call, then the headset and the mobile phone exchange the signaling messages specified, for instance, by the Bluetooth headset profile, for instance, the RING command to produce the typical incoming call sound in the Headset. The signaling messages trigger the Bluetooth connection, in general the short-range wireless communication link, to be used for the audio-stream.

The advantage of the body-coupled communication link particularly compared to the Bluetooth communication link is its relatively low electric power consumption. As a result, the body-coupled communication link can be activated as soon and as long as the first and second communication devices are turned on. Thus, if the short-range communication link between the two communication devices has to be established and maintained utilizing the signaling data, the signaling data can be transmitted immediately without having the body-coupled communication link to be switched from a sleeping mode to an activated mode. This results, particularly when used for the mobile phone and the headset, in a faster establishing of the short-range wireless communication link, which especially is a Bluetooth communication link.

The object is also achieved in accordance with the invention by means of a system for exchanging data, comprising: a first communication device comprising a first short-range wireless communication interface and a first body-coupled communication interface; and a second communication device comprising a second short-range wireless communication interface and a second body-coupled communication interface, wherein the first communication device is configured to send signaling data by its first body-coupled communication interface to the second body-coupled communication interface of the second communication device in order to establish a short-range wireless communication link between the two short-range communication wireless interfaces of the two communication devices.

The first communication device may be an audio gateway and the second communication device may be a headset. The two short-range communication wireless interfaces may particularly be Bluetooth interfaces. Further, the first body-coupled communication interface of the first communication device may be turned on continuously, as soon as the first communication device is turned on. The same applies to the second body- coupled communication interface of the second communication device.

The first communication device may comprise a wireless communication interface for having a communication link between the first communication device and a telecommunication or data network and the signaling data are used to establish the communication link.

The first communication device may be a mobile phone and the second communication device may be a headset, so that, when the mobile phone receives an incoming telephone call or initiates an outgoing telephone call, the mobile phone and the headset exchange the signaling data by means of the body-coupled communication interfaces in order to establish and control an audio-stream link between the mobile phone and the headset utilizing the short-range wireless communication link. Those skilled in the art will easily appreciate that the first communication device is not restricted to a mobile phone, but may be any audio device like a hi-fi unit, an MP3 player, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail hereinafter, by way of non- limiting examples, with reference to the embodiments shown in the drawings. Fig. 1 is a person wearing a headset and having a mobile phone; Fig. 2 is a diagram generally illustrating the establishment and the control of a communication link between the headset and the mobile phone;

Fig. 3 is a table summarizing page and page scan parameters; Fig. 4 is a diagram illustrating the establishment of the communication link between the headset and the mobile phone for an incoming telephone call; Fig. 5 is a diagram illustrating the establishment of the communication link between the headset and the mobile phone for an outgoing telephone call; and

Fig. 6 illustrates the detection of a lost body-coupled communication link between the headset and the mobile phone.

DESCRIPTION OF EMBODIMENTS

Fig. 1 shows a person 1 wearing a headset 2 and having a mobile phone 3 close to his/her body. The mobile phone 3 is an example of an audio gateway. The headset 2 comprises a body-coupled interface 4, a Bluetooth interface 5, a loudspeaker 10, and a microphone 11. The mobile phone 3 comprises a body-coupled interface 6 and a Bluetooth interface 7. The person 1 can receive and initiate telephone calls with his/her mobile phone 3. For this purpose, the mobile phone 3 can be wirelessly connected to a telephone network 8 via an antenna 9 of the mobile phone 3.

Bluetooth comprises a so-called "headset profile", which supports communication between the headset 2 and the mobile phone 3 (or generally an audio gateway), utilizing the Bluetooth interfaces 5, 7. Thus, during a telephone call, a communication link can be established between the mobile phone 3 and the headset 2.

The Bluetooth headset profile specifies how to implement a connection between a Bluetooth headset 2 and a Bluetooth audio gateway, which for the exemplary embodiment is the mobile phone 3 equipped with a Bluetooth interface.

For the connection between the headset 2 and the mobile phone 3 during a telephone call, two channels are needed: A first channel for the audio-stream and a second channel for the signaling data.

Data signaling uses so-called AT commands and result codes, which are sent over an RFCOMM link. RFCOMM is the abbreviation for Radio Frequency Communication. The Bluetooth protocol RFCOMM is a simple set of transport protocols, providing emulated RS232 serial ports (up to sixty simultaneous connections of a Bluetooth device at a time). Thus, RFCOMM sometimes is referred to as "Serial Port Emulation". The Bluetooth Serial Port Profile is based on this protocol. The AT commands are messages sent from the headset 2 to the mobile phone 3 and the result codes are messages sent from the mobile phone 3 to the headset 2.

The Bluetooth headset profile specifies the AT commands and the result codes that must be used (see Section 4.7 of Bluetooth headset profile). The AT capabilities (AT commands and unsolicited result codes) specify: The indication of an incoming call from the audio gateway (mobile phone 3); the setting of the gain of the microphone 11 from the mobile phone 3 to the headset 2; the report of the gain of the microphone 11 from the headset 2 to the mobile phone 3; the setting of the gain of the loudspeaker 10 from the mobile phone 3 to the headset 2; the report of the gain of the loudspeaker 10 from the headset 2 to the mobile phone 3; the indication issued by the headset 2 that the headset 2 is turned on.

The audio-stream between the headset 2 and the mobile phone 3 is sent over a Synchronous Connection Oriented (SCO) link 14 utilizing the Bluetooth interfaces 5, 7. The mandatory voice codec is the Continuous Variable Slope Delta Modulation (CVSD) for the exemplary embodiment. In order to avoid delays in the data signaling and to improve the power consumption of the mobile phone 3 and the headset 2, the body-coupled interfaces 4, 6 of the headset 2 and the mobile phone 3, respectively, are utilized to form a body-coupled communication link 12 for the signaling data. For the exemplary embodiment, the body- coupled communication link 12 is used for sending the signaling data when there are no ongoing telephone calls. Then, there is also no audio-stream. When the data signaling is sent over the body-coupled communication link 12 between the mobile phone 3 and the headset 2, then the Bluetooth interfaces 5, 7 are turned off completely.

Fig. 2 illustrates how to establish the connection between the headset 2 and the mobile phone 3 during a telephone call. Initially, a Bluetooth configuration 20 for configuring the headset 2 and the mobile phone 3 has to be carried out. The Bluetooth configuration 20 can include Bluetooth device discovery (inquiry and paging), Bluetooth service discovery, and Bluetooth bonding (pairing) between the headset 2 and mobile phone 3. This has to be done only once, so that the two devices 'know' each other. When the initial Bluetooth configuration 20 is completed, the mobile phone 3 and the headset 2 set up their body-coupled communication link 12. This set-up includes exchanging the corresponding body-coupled BCC addresses (BCC_ADDR_HS/AG) via a Bluetooth communication link 13 between the headset 2 and the mobile phone 3 utilizing the respective Bluetooth interfaces 5, 7. Additionally, the headset 2 and the mobile phone 3 check the availability of the connectivity via body-coupled communication link 12 by an initial message exchange triggered by the mobile phone 3.

When the Bluetooth configuration and the body-coupled communication link 12 configuration are successfully completed, the Bluetooth communication link 13 is closed and the Bluetooth interfaces 5, 7 of the mobile phone 3 and the headset 2 are shut down for the exemplary embodiment. This is illustrated by a broken arrow 13 a. The mobile phone 3 stores the Bluetooth address and the Bluetooth native clock of the headset 2 for the next Bluetooth connection. The Bluetooth address is called "BD ADDR_HS" and the Bluetooth native clock is called "CLKN_HS" for the exemplary embodiment. From that point in time, signaling data is transmitted utilizing the body-coupled communication link 12.

Due to an internal event, for instance an incoming telephone call 22, or a user- initiated action 23 in the mobile phone 3 or in the headset 2, the mobile phone 3 or the headset 3, respectively, sends the related signaling data over the body-coupled communication link 12. Thus, the result codes for the mobile phone 3 or the AT commands for the headset 2 are sent over the body-coupled communication link 12. This is illustrated by an arrow 15. The first signaling message that is sent triggers the activation of the two Bluetooth interfaces 5, 7 in order to establish the Bluetooth communication link 13. This is illustrated by an arrow 16 in Fig. 2.

After the build up of the Bluetooth communication link 13 has been completed, the SCO link 14 is established utilizing the Bluetooth communication link 13 and the signaling data are sent over the Bluetooth communication link 13 until the SCO link 14 is released. The SCO link 14 is used for exchanging an audio-stream between the mobile phone 3 and the headset 2.

When the SCO link 14 is released, for instance by an internal event 24 or an internal action of the mobile phone 3 or an initiated action 25 of the person 1, as it is specified in the Bluetooth headset profile, the Bluetooth interfaces 5, 7 of the headset 2 and the mobile phone 3 are shut down (broken arrow 13b) again and the data signaling, such as the AT commands and result codes, are sent over the body-coupled communication link 12 (arrow 17). Fig. 3 shows page parameters respectively interlaced page scan parameters and associated values for a Bluetooth connection. Page Timeout is set to 5120 ms, T_{W PAGE SCAN} to 10.625 ms, T_PAGE SCAN to 21.250 ms, and Page Scan Timeout to 5120 ms.

Fig. 4 illustrates the establishment of the Bluetooth communication link 13 between the headset 2 and the mobile phone 3 for the incoming telephone call 22 and Fig. 5 illustrates the establishment of the Bluetooth communication link 13 for an outgoing telephone call.

When the mobile phone 3 receives the incoming telephone call 22 over its antenna 9 from the telecommunication network 8, then the mobile phone 3 sends a RING signal over the body-coupled communication link 12 to the headset 2. This action is illustrated by an arrow 40. Then, the Bluetooth communication link 13 is established and the RING signal is sent over the Bluetooth communication link 13 from that point in time. This action is illustrated by an arrow 41. Then, the headset 2 sends the AT commands (arrow 42) over the Bluetooth communication link 13. The mobile phone 3 sends an OK signal (arrow 43) over the Bluetooth communication link 13. Then, the SCO link 14 is established utilizing the Bluetooth communication link 13.

When the person 1 initiates a telephone call (user initiated action 23), then the headset 2 may send the AT commands to the mobile phone 3 over the body-coupled communication link 12 (arrow 50) and the mobile phone 3 sends an OK signal to the headset 2 over the body-coupled communication link 12 (arrow 51). Then, the Bluetooth communication link 13 and the SCO link 14 are established.

In case the body-coupled communication link 12 breaks down, for instance, because the mobile phone 3 or the headset 2 are not close enough to the person's 1 body, the Bluetooth communication link 13 is established by turning on the Bluetooth interfaces 5, 7 of the headset 2 and the mobile phone 3 for the exemplary embodiment. For the exemplary embodiment, the Bluetooth communication link 13 is established one second after the breakdown of the body-coupled communication link 12 has been detected.

One method of detecting a broken-down body-coupled communication link 12 is that the lower body-coupled layers are responsible for detecting the link loss (e.g. regular poll from the mobile phone 3 to the headset 2). If the poll is not answered, then an event is generated to start the body-coupled Bluetooth timeout for utilizing the Bluetooth communication link 13 for the signaling data.

A further method of detecting a lost body-coupled communication link 12 is illustrated in Fig. 6. The application layer of the body-coupled communication link 12 performs a periodic polling 61 from the mobile phone 3 to the headset 2 by means of AT commands. For the exemplary embodiment the extended AT command "+P" is used as a poll packet from the mobile phone 3 to the headset 2. If the body-coupled link 12 is active, then the headset 2 sends an appropriate response 62 to the mobile phone 3. The time between two pollings 61 is the polling time and may be between 10- 1000 msec (default value is 100 msec).

Whenever the body-coupled communication link 12 becomes available again, the signaling data are sent over the body-coupled communication link 12 again, the Bluetooth communication link 13 is closed, and the Bluetooth interfaces 5, 7 are shut down.

The body-coupled communication link 12 may be encrypted and authentication can be done as well. The Bluetooth parameter link key and a PIN number may be used to set up the encryption and authentication over the body-coupled communication link 12.

Finally, it should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be capable of designing many alternative embodiments without departing from the scope of the invention as defined by the appended claims. In the claims, any reference signs placed in parentheses shall not be construed as limiting the claims. The words "comprising" and "comprises", and the like, do not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. The singular reference of an element does not exclude the plural reference of such elements and vice versa. In a device claim enumerating several means, several of these means may be embodied by one and the same item of software or hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CLAIMS:

1. A method of establishing and controlling communication between two communication devices, the method comprising the steps of: transmitting signaling data from a first communication (3) device to a second communication device (2) by means of a body-coupled communication link (12) in order to establish communication between the two communication devices (2, 3); and operating the communication between the two communication devices (2, 3) by means of a short-range wireless communication link (13) between the two communication devices (2, 3).

2. The method of claim 1, comprising the step of transmitting the signaling data for controlling an ongoing communication by means of the body-coupled communication link (12) or by means of the short-range communication wireless link (13).

3. The method of claim 1, wherein the signaling data are used to establish communication between the first communication device (3) and a telecommunication or a data network (8) by means of a wireless communication link.

4. The method of claim 1, wherein the first communication device is a mobile phone (3) and the second communication device is a headset (2), so that, when the mobile phone (3) receives an incoming telephone call (22) or initiates an outgoing telephone (23) call, the mobile phone (3) and the headset (2) exchange the signaling data by means of the body-coupled communication link (12) in order to establish an audio-stream (14) between the mobile phone (3) and the headset (2) utilizing the short-range wireless communication link (13).

5. The method of claim 1, wherein the short-range wireless communication link is a

Bluetooth communication link (13) and/or the body-coupled communication link (12) is active as soon as the two communication devices (2, 3) are turned on.

6. A system for exchanging data, comprising: a first communication device (3) comprising a first short-range wireless communication interface (7) and a first body-coupled communication interface (6); and a second communication device (2) comprising a second short-range wireless communication interface (5) and a second body-coupled communication interface (4); wherein the first communication device (2) is configured to send signaling data by its first body-coupled communication interface (6) to the second body-coupled communication interface (4) of the second communication device (2) in order to establish a short-range wireless communication link (13) between the two short-range communication wireless interfaces (5, 7) of the two communication devices (2, 3).

7. The system of claim 6, wherein the first communication device (3) sends the signaling data for controlling an ongoing communication to the second body-coupled communication interface (4) of the second communication device (2) by its first body- coupled communication interface (6) or wherein the first communication device (3) sends the signaling data for controlling an ongoing communication to the second short-range communication wireless interface (5) of the second communication device (2) by its first short-range communication wireless interface (7).

8. The system of claim 6, wherein the first communication device (3) comprises a wireless communication interface (9) for having a communication link between the first communication device (3) and a telecommunication or data network (8) and the signaling data are used to establish the communication link.

9. The system of claim 6, wherein the first communication device is a mobile phone (3) and the second communication device is a headset (2), so that, when the mobile phone (3) receives an incoming telephone call (22) or initiates an outgoing telephone call (23), the mobile phone (3) and the headset (2) exchange the signaling data by means of the body-coupled communication interfaces (4, 6) in order to establish an audio-stream link (14) between the mobile phone (3) and the headset (2) utilizing the short-range wireless communication link (13).

10. The system of claim 6, wherein the first short-range wireless communication interface is a first Bluetooth interface (7) and the second short-range wireless communication interface is a second Bluetooth communication interface (5) and/or the body-coupled communication interfaces (4, 6) are active as soon as the two communication devices (2, 3) are turned on.