Method and apparatus for dual/multi-watch for group ptt services

<u>FIELD OF THE INVENTION</u>

0001The invention generally relates to communication systems and more particularly to managing calls across multiple push-to-talk (PTT) devices.

<u>BACKGROUND OF THE INVENTION</u>

0002Push-to-talk (PTT) is a two-way communication service that operates like a "walkie talkie." PTT is half-duplex, meaning communication can only travel in one direction at any given moment. By contrast, a typical cell phone call is full-duplex, meaning both parties can hear each other at the same time. There also exists communication devices that provide both full-duplex and half-duplex capabilities. PTT requires the person speaking to press a button on the communication device while talking and then release it when they are done. The listener then presses a PTT button on their own communication device to respond. Most PTT systems allow group calling, meaning one person can speak to everyone in their assigned or current group at once, just by pressing a PTT key. Some PTT systems use voice-over-IP (VoIP) technology to provide PTT service digitally over digital data networks. Public safety personnel, such as police officers, firefighters and rescue workers to name a few, utilize a variety of different communication devices in the field, including portable handheld radios, cell phones, mobile (vehicular) radios and accessories.

0003Public safety personnel often desire to listen to multiple PTT groups at one time. Typical solutions managing multiple PTT groups include scanning the groups listed in a scan list by various methods, then playing the audio when traffic is detected. Priorities are usually used in the scan list. Conventional scanning typically involves tuning to different radio frequency (RF) frequencies one by one and staying tuned to a frequency when activity is detected. Trunked scanning typically involves having an infrastructure entity report which groups have activity, with enough information to allow the radio to listen in on desired groups by tuning to a channel. However, both conventional scanning and trunked scanning are prone to missed calls, particularly when there is audio activity on two or more groups.

0004Accordingly, it would be desirable to improve call management in communication systems that utilize numerous communication devices. <patcit id="pcit0001" dnum="US20040031058A"><text>US2004/0031058</text></patcit> teaches hyperlink clicking that can be specifically directed to a specific user device, based on the type of link. Data is directed to a user device, based on the type of information to be displayed. A session transfer from a first device to a second device may occur in response to the second device powering up and then pulling the session from the first device. <patcit id="pcit0002" dnum="US20070197248A"><text>US2007/0197248</text></patcit> provides a wireless device to simultaneously monitor multiple PTT communication groups. <patcit id="pcit0003" dnum="US20070136768A"><text>US2007/0136768</text></patcit> provides a <i>'home gateway'.</i> The home gateway may receive many video/audio input signals that arrive at a person's home, such as live video from an entrance way surveillance camera. The home may contain many home network devices, each able to display one of the signals. US'768 is concerned with there being too many remote control devices for the various home network devices, and may <i>'eliminate the requirement of having multiple remote control devices to control separate devices in the home'.</i> One remote control may operate in a <i>'redirect'</i> mode, whereby the remote control device determines which of the many video/audio input signals will be delivered to each of the home network devices.

<u>BRIEF DESCRIPTION OF THE FIGURES</u>

0005The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> is a block diagram of a communication system having multiple devices operating in accordance with various embodiments of the invention.</li><li><figref idref="f0002">FIG. 2</figref> is a flowchart of a method for managing multiple calls from multiple devices within a communication system in accordance with various embodiments of the invention.</li></ul>

0006Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

<u>DETAILED DESCRIPTION OF THE INVENTION</u>

0007Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in apparatus components and methods related to managing multiple calls across multiple devices via the use of dual watch or multi-watch.

0008Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

0009In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises ...a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

0010In the description herein, numerous specific examples are given to provide a thorough understanding of various embodiments of the invention. The examples are included for illustrative purpose only and are not intended to be exhaustive or to limit the invention in any way. It should be noted that various equivalent modifications are possible within the scope of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced with or without the apparatuses, systems, assemblies, methods, components mentioned in the description.

0011The call management technique and apparatus to be described herein is accomplished using dual watch and optionally also multi watch. Dual-watch is the ability to simultaneously listen to audio activity in two groups. Multi-watch is the ability to listen to two or more groups simultaneously. Dual-watch is accomplished by some public safety users by tuning multiple radios to different groups. These users are accustomed to listening to simultaneous call streams, typically occurring with a mobile (vehicle-based) radio and a portable (handheld) radio. It should be noted that although it is counter-intuitive, public safety users are accustomed to processing simultaneous audio streams and tuning into a desired audio stream, even in the presence of many other competing audio sources, including multiple radio transmissions. While prior approaches to dual watch have focused on multiple transceivers for call termination at a single device, the ability to manage multiple calls from multiple devices, such as calls coming in over different public safety broadcasts, would be highly beneficial. Briefly, in accordance with various embodiments of the invention to be described herein, a method and apparatus provide dual/multi-watch across multiple devices along with intelligent call management. Additionally, the use of a VoIP path for dual/multi-watch is provided.

0012Users working in the public safety environment commonly carry both a cellular phone and a two-way radio, which for the purposes of this application will be referred to as a phone and a radio, respectively. There are phones that support PTT calls and some that support group PTT calls over a cellular network. The PTT service is typically handled over an internet protocol (IP) stream, such as the Open Mobile Alliance push-to-talk over cellular (OMA PoC) standard. Such a service uses a software application that, for the purposes of this application, will <u>be</u> referred to as a PTT-VoIP client.

0013The call management configuration operating in accordance with the various embodiments of the invention provides a way of accomplishing dual watch by receiving simultaneously on a radio and a phone. The configuration has an added feature of being able to receive more than two audio streams on the phone thereby enabling multi-watch. Referring to <figref idref="f0001">FIG. 1</figref> there is shown a communication system 100, such as a public safety network, operating in accordance with the various embodiments of the invention. Communication system 100 includes a plurality of communication devices 130 under the control of a user. The plurality of communication devices and accessories 130 includes a radio 102, a phone 104, a mobile (in-vehicle) radio 106, an earpiece 108 and a remote speaker microphone (RSM) 110. The radio 102, the phone 104, the mobile radio 106, the audio earpiece 108, and the RSM 110 have speakers providing audio sinks over which the user hears audio. The speaker of radio 102 is a loud speaker and for the purposes of this application provides a preferred location for porting audio of a higher priority group, or porting a call a user is more actively involved in. The devices in 130 are operably coupled over a personal area network (PAN) or other coupling means. Additional devices or fewer devices may also be used, but those shown illustrate a realistic example of the numerous devices a public safety officer may need to manage at any given time. A PTT-VoIP application resides in at least one of the devices to support PTT calls over an alternate network 118.

0014Communication system 100 is linked via a gateway component 114 which performs an application-layer conversion of information from one protocol stack to another, such as land mobile radio (LMR) network 112 to the alternate network 118 (and vice versa). The gateway component 114 includes LMR gateways. LMR gateways provide voice interoperability between radio and non-radio networks by bridging radio frequencies to IP streams, such as produced by alternate network 118. Examples of LMR networks are those that adhere to the APCO Project 25 standard and the Tetra standard. Examples of alternate networks are CDMA EVDO and GSM HSDPA cellular data/voice networks.

0015In accordance with various embodiments, the dual/multi-watch is managed with a coordinated approach between the devices 102, 104, 106, 108, and 110. The coordination can be implemented by a single PTT VoIP client in the radio 102 or phone 104 or mobile radio 106, or by multiple PTT VoIP clients in communication over a PAN. Regardless of the VoIP client location, the features of the call management operate as follows. The user of the plurality of devices 130 has a single list of groups they are interested in listening to, with preference rules describing the type of operation desired for each group. The list has prioritization. The prioritization can be the traditional allocation of a first priority group, a second priority group, and the rest normal priority, or any other form of prioritizing between the groups the user wishes to configure. The prioritization may also be based on the type of incoming PTT call is being received, such as emergency given highest priority while non-emergency calls would be assigned lower priority. Another preference stored within the list is the designation of a preferred audio device, which denotes which device is preferred for the highest priority audio. In most public safety applications, the highest priority audio would likely be defaulted to the radio 102. The selected default is based on historical data that has shown that users who carry a radio are most likely to have that device on their person than any other, and prefer PTT audio through that device. However, as user applications may vary, different devices could be selected as the default, or assigned different priorities, if desired.

0016In one embodiment, the highest priority active call traffic is played through the preferred audio device, and the next highest priority call audio is played through another device. As traffic starts and stops, audio may move to the second device if a higher priority group has activity, or the system may let that current transmission play out before moving subsequent transmissions to the second device since PTT transmissions tend to be very short (3-5 seconds). So for the case of the highest priority audio being assigned to the radio 102, two incoming calls would result in the highest priority call playing out the radio 102 and the next highest priority call playing out the phone 104. A third and fourth call coming in to the user of devices 130 could be played out at mobile radio 106 or earpiece 108, RMS 110 or other prioritized audio sinks.

0017The call management technique in accordance with various embodiments can also address mobility within the system. A distributed mobility approach is defined to choose between narrowband (NB) path between 112 and 114, and VoIP path between 114 and 118 for monitoring a group. The call management expands to allow for dual/multi-watch considerations, whereby a specific group can be monitored using the NB radio 102, and the other groups can be monitored via the VoIP path. It is likely, but not necessary, that the highest priority group would be the one assigned to the NB radio 102.

0018Among the considerations for where to place the PTT VoIP client, choosing to have the PTT VoIP client in the radio 102 and not in the phone 104 allows the radio 102 to use an off-the-shelf phone 104 using a standard modem profile from a PAN technology such as Bluetooth.

0019An alternative embodiment is to have the PTT VoIP client in the phone 104 and have the phone 104 forward audio over the PAN to the radio 102 thereby handling the call processing in the phone.

0020Additionally in yet another embodiment, the PTT VoIP client can exist in both the phone 104 and the radio 102. This embodiment allows redundancy because PTT-VoIP calls can be handled in either device.

0021Another aspect to the various embodiments of call management is the handling redundancy. If the devices lose PAN connectivity, or by manual setting or other means it is determined that the user wants to restrict operation to a single device, dual/multi-watch can be restricted to that device, to the degree that the single device is capable. If this single device mode happens and PAN connectivity is still there, the other device can still be used purely as a modem.

0022The call management technique operating within a communication system provides the advantage of spatial separation between audio sinks making multiple audio streams easier to understand. The call management technique is further advantageous in a mobile (vehicle) configuration where there is further spatial separation between the audio sinks. In addition to having spatial separation between audio sinks the call management technique may sum two or more call audio streams to a single audio sink when based on assigned device priority and call priority.

0023Referring to <figref idref="f0002">FIG. 2</figref>, the call management technique 200 in accordance with various embodiments is shown. Step 202 begins by detecting audio activity on a channel (for example C1) from a scan list. As mentioned before the scan list is pre-stored and the types of incoming calls and groups are prioritized. A check is made at 204 to determine if the primary device is playing audio, if not then the audio traffic on channel C1 is played on the primary device at 206. If a determination is made at 204 that audio is being played on the primary device, then a determination is made at 205 as to which channel the audio originates from and then a priority check is made at 208. If channel C1 does not have a higher priority than channel C2 at 208, then a determination is made at 210 as to whether the secondary device is playing audio at 210. If the secondary device is not playing audio at 210, then audio traffic from channel C1 goes to the secondary device at 214. If audio is already being played on the secondary device at 210, then the C1 audio is summed to the audio on the secondary device at 212.

0024If channel C1 does have higher priority than channel C2 back at 208, then a check is made to determine if audio is playing on the secondary device at 216. If the secondary device is not playing audio at 216, then channel C1 audio is played on the primary device and channel C2 audio is moved over to the secondary device at 220. If audio is played on the secondary device at 216, then channel C1 audio plays on the primary device, and the C2 audio is moved over to be summed with the current audio playing on the secondary device at 218. While described in terms of two devices, technique 200 is expandable to encompass as many prioritized devices as are in the communication system 100. Technique 200 may also vary based on device audio preferences, audio summing preferences, and allocation of a given group or priority to a device, as previously described.

0025In the embodiment just described the channels are assigned the priorities for scan. However, in an alternative embodiment the call priority can be based on the type of incoming PTT being received. For example, in APCO systems the calls have only one of two priorities (emergency or not), but in Tetra and OMA PoC systems, the calls have a numeric priority. The comparison steps associated with flowchart 200 can be based on the priority of the type of call and be played out according to the prioritized devices. So for example, if preferred group call is played out over radio 102 while another group call is being played out over phone 104, and an emergency call comes in, then the emergency call, having the highest priority, would bump, the preferred group call over to the phone and the other group call would be bumped over to the mobile radio 106 or the earpiece 108 or the RSM 110 depending on how the devices were prioritized. Calls can also be summed to play out of the same device at different times as has also been described.

0026Accordingly, there has been provided a method and apparatus for managing calls across multiple devices. The call management technique is beneficial to government and public safety type operations where multiple calls may be coming in to a listener of multiple devices at the same time. Unlike the prior approaches to dual watch which have focused on multiple transceivers/speakers, each dedicated to a channel or group. The call management operating in accordance with the various embodiments provides dual/multi watch across multiple devices and manages them intelligently resulting in fewer missed calls, improved audio intelligibility, and device redundancy. The call management technique can also be readily adapted as different applications relating to priority arise.

0027Those skilled in the art will appreciate that the above recognized advantages and other advantages described herein are merely exemplary and are not meant to be a complete rendering of all of the advantages of the various embodiments of the present invention.

0028In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention.