Packet-data-based area group communication

ES 2 294 643 T3

DESCRIPTION

Group communication within an area based on data packets.

Field of the invention

The invention relates to the field of telecommunications systems, in particular to the implementation of group communication within an area based on data packets in a telecommunications system.

Background of the invention

A special feature in telecommunication systems is group communication. Particularly with regard to voice calls, group communication has traditionally been implemented in linked mobile phone networks, such as PMR (Private Mobile Radio) networks, which are special mobile phone networks created for use by authorities and companies. Recently, however, certain solutions have been provided in which a group call can be implemented in public land mobile telephone networks or other data networks. The term "group" refers, in this context, to any predetermined group comprising two or more users or subscribers of the mobile station who can participate in the same communication group, typically the same group call. In PMR networks, the mobile service subscribers of a given group typically belong to the same organization, while in solutions based on public mobile phone networks, also private persons can establish communication groups on their own. A subscriber to the mobile service can naturally belong to several groups.

Currently, packet-based group communication implementations for both voice and data calls have been developed for cellular networks, particularly for GSM / GPRS / UMTS networks. The starting point of such group communication implementations is generally that the mobile system used provides only the required communication connection, such as an IP connection, and the actual implementation of the group communication service has been constructed as a protocol layer. application or separate user on top of the telecommunication connection used. Group communication services are typically implemented as VoIP (Voice over IP) solutions. In this case, a group communication application can be implemented as a client-server solution in which the telecommunications network comprises a group communication server, and applications used as a client terminal. When such a cellular network solution is used for a radiotelephone-type “push to talk” call, the term PoC network (push to talk over a cellular network) is generally used.

Such a radiotelephone type group call is generally based on a "push to talk, release to listen" function, in which the group call is established by pressing a button (tangent) located on the terminal and which functions as a call switch. By pressing the button, the user expresses his desire to speak, and the terminal sends a service request to the network. The network either rejects the request or assigns the required sources based on predetermined criteria, such as the availability of resources and the priority of the requesting user. At the same time, a connection is established with all other active users within the subscriber group within which the terminal submitted the call request. After the voice connection has been established, the requesting user can speak and the rest of the users can listen over the channel. Once the user releases the button, the user terminal signals a release message on the network, and the resources are released, after which all other members of the group can similarly request a call connection.

Such a radiotelephone-like group call is a particularly useful form of communication for geographically limited events, such as festivals, sporting events, or hunts, because it is easy for members of a particular group participating in the event to keep in touch with everyone else group members.

A problem with such a solution of a PoC network of the indicated type is, however, that the members of a PoC group remain active within the group even if they have moved away from the event area, because a PoC group call connection is established. throughout the coverage area of ​​the mobile phone network. Thus, members who have been active in the group remain active when leaving the event area if they do not remember to separately disconnect the group call connection. In the same way, when a group call is established, an invitation is sent to all members of a given group, although some members of the group may be far from the event area. Thus, no one participating in a PoC group call can be sure that all other group members are nearby, which can complicate the group's planned actions.

Document WO 03/026205 discloses a talk group communications method in which the transmission of a talk message may depend on the current geographical position of a receiving device. A chat service center may be arranged to transmit the chat message to other participants located within a predetermined area located around the participant sending the participation message.

Document US 2004/082351 discloses a procedure for establishing a group of users in which a temporary group of users is established by means of short-range communication links between the

ES 2 294 643 T3 terminal devices of users. Terminal devices can connect to an application server, which can connect to a presence server for presence information.

Document WO 03/051000 discloses a broadcasting arrangement in point-to-point oriented packet switched networks. The arrangement comprises a multicast / broadcast management center for controlling the multicast / broadcast services. Multicast can be used to send broadcast data to network nodes within a geographic broadcast group specified by the broadcast management center.

Brief description of the invention

An object of the invention is therefore to provide a method and an apparatus that implements the method whereby the activity of the members of an IP-based voice communication group may specifically be location-restricted. The object of the invention is achieved with a method, a system, a server and a computer program that is characterized by what is stated in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

The starting point of the invention is a method in which an IP-based voice communication group is established in a mobile telephone system comprising several terminals as well as at least one wireless access network and one packet data network. , such as a GPRS network, connected to it, to transmit IP data packets between the terminals and at least one server that controls the voice communication of the group. The basic idea of ​​the invention is to establish site-bound specifications for the voice communication group to be established comprising a predetermined maximum distance from a reference point, set between the members of the group; and establishing an IP-based voice communication group between at least two of the terminals, requiring the activation of the group members at the location within an area of ​​activity determined by the maximum distance.

An advantage of the invention is that the establishment of a PoC group call connection and its active maintenance can be restricted in a certain geographical area such that the members of the group can be active only with respect to the group only within one area of ​​activity. determined in each specific case. In this way you can be sure that all members of the group are in the immediate vicinity. If any member of the group leaves the given activity area, he / she can be removed from the PoC group call connection.

An embodiment of the invention comprises transmitting with a first terminal a start request for an IP home group voice communication with at least one server controlling the group voice communication; controlling the specifications related to the location of the voice communication group that comprise the activity area of ​​the voice communication group; controlling the location information of at least one particular terminal of the initiation request for group voice communication; and in response to the location information of the at least one terminal indicating that the terminal is located in the activity area of ​​the voice communication group, establishing an IP-based voice communication group between the first terminal and the at least one terminal determined in the start request for group voice communication.

An embodiment of the invention comprises storing in the server unit the specifications related to the location of the voice communication group in which the area of ​​activity of the voice communication group is limited to the location of a terminal belonging to the group . Thus, the reference point can be mobile, so that when the group activity requires the group to move together, for example in the case of a hunting club, the activity area is automatically updated according to the location. terminal that serves as a reference point.

Alternatively, the specifications related to the location of the voice communication group determining a predetermined geographic area as the activity area of ​​the voice communication group are stored in the server unit. In this way, the determination of the area of ​​activity can be advantageous for example in sporting events limited to a certain place.

An embodiment of the invention comprises determining the area of ​​activity as the area that covers one or more cells of a mobile telephone network. In the method of the invention, the location of the terminal does not have to be determined particularly precisely, so that the precision of the particular cell is typically sufficient to apply the invention, likewise, the information of the location of the particular cell is directly applicable in PoC system.

An embodiment of the invention comprises setting a condition based on the presence condition for at least one member of the voice communication group to activate the member for the IP-based voice communication group. Thus, a specification can be established for the application server according to which site relationship is in use in a given terminal in given presence profiles (for example an encounter profile), while in other presence profiles the location relationship.

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An embodiment of the invention comprises the transmission to the members of the voice transmission group, information of the activation of other members of the group for the IP-based voice communication group as presence information displayed on the screens of the terminals . In this way, the members of the group receive an illustrative indication of the other members of the group.

Brief description of the figures

The invention will now be explained in greater detail with respect to preferred embodiments, with reference to the accompanying drawings, of which:

Figure 1 shows a basic structure of a PoC network arrangement;

Figure 2 shows a PoC network arrangement in greater detail in connection with a GSM / GPRS network, and an application server according to an embodiment of the invention; and Figure 3 shows a simplified signaling diagram of the initiation of a site-related PoC session.

Detailed description of the invention

The present invention can be applied to any packet switched mobile telephone system. The invention is preferably particularly applicable to mobile telephone systems based on packet radio communication of the GPRS type. Also, the invention can be applied in situations where part of the data transfer, for example the data transfer from part of the PoC system, takes place via a switched link telecommunication connection. In the following, basic embodiments of the invention will be described by means of a GPRS service and a UMTS or GSM system without limiting the invention to this particular packet radiocommunication system. The IP voice communication method used in the basic embodiments of the invention is the Voice over IP (VoIP) method, but the invention is not limited to this particular method.

Figure 1 shows the basic structure of a PoC network arrangement in general terms. In Figure 1, above the mobile telephone system, a group communication service 100 based on packets of data has been implemented, in which the user plane functions (UPF) and the control plane functions (CPF ) have been differentiated from each other. The underlying mobile telephone network comprises a main network (CN) and a radio access network (RAN), with which the user terminals UT1 to UT3 have a radio frequency connection. The mobile phone network can be, for example, a second generation (2G) GSM / GPRS network or a third generation (3G) UMTS network. A wireless local area network (WLAN) can also function as a radio RAN. The type and structure of the mobile phone network used in the PoC network arrangement is not, as such, essential in relation to the implementation of the PoC service as long as the mobile phone network provides a telecommunication connection based on data packets for PoC service. Thus, any packet-switched mobile phone system can be used to implement the network service.

The group communication service 100 can be implemented, for example, as a server system comprising one or more servers, up to which subscriber communication from the terminals is transmitted by means of a proxy, because a PoC service typically does not allow direct an end-to-end data transmission between the terminal and the servers. The PoC server system 100 comprises as separate logic functions User Plane Functions (UPF) and Control Plane Functions (PCF) that communicate with PoC client terminal applications via a packet-based connection. data, typically an IP-based connection provided by the mobile phone network. This data transmission comprises both the transfer of user information (voice / data packets) and the signaling related to group communication. The logical functions of the server system 100 can be implemented with one server, or they can be appropriately distributed among several servers.

The task of the UPF user plane functions is to distribute the voice / data packets to the group terminals according to their group specifications and other parameters. A prerequisite to the data transfer by UPFs is that the PCF control functions have first established and configured logical user plane connections with other members of the group. A voice group call can be based on the VoIP and / or RTP (Real Time Protocol) protocol. As a main rule, a PoC voice call works in such a way that all voice packets from subscriber A are routed to the UPF function, which subsequently distributes the voice packets to all subscribers B belonging to the group using the appropriate data transfer technology, such as a single packet transmission to all subscribers (multicast) or several different single packet transmissions to all subscribers (multicast).

The Control Plane Functions (PCF) include the control and management of group calls. This includes the aforementioned establishment, configuration and deletion of specific group user plane logical connections using an appropriate call control protocol, such as a SIP (Session Initiation Protocol), addition and deletion of group specifications users, and user registration and authentication.

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As a logical function, the PoC server system 100 may comprise a group and subscriber management function (SGMF), which comprises the required functions of managing subscriber and group data and reserving the resources required by subscribers and the groups. The SGMF transmits the required information to the CPF, for example when defining group specifications. The Subscriber and Group Management Function (SGMF) can be controlled by means of a WWW-based control interface that can be used with popular network browsers. The PoC server system 100 may also comprise a register (RG) in which the resource reservations of subscribers and groups, determined in the SGMF, are stored.

Figure 2, in which the aforementioned functionalities are described in greater detail in a GMS / GPRS network, also illustrates an application server according to the invention, as well as its operation. Figure 2 shows only part of the network elements of a GSM / GPRS network. The GSM / GPRS network also comprises a large number of other network elements, the description of which is not relevant for the understanding of the invention in the present context.

With respect to the GSM network, Figure 2 illustrates as an access network only the radio network RAN ​​(Radio Access Network), which comprises a base station controller (BSC) as well as typically several base transceiver stations. (BTS) connected to the base station controller (BSC), the available radio channels and frequencies of the base transceiver station (BTS) being controlled by the base station controller (BSC). Around each base transceiver station, a cell is constituted, and together, they constitute a cellular network whose geographical coverage is fundamentally determined on the basis of the location of the base stations. Each cell is identified with a particular cell identifier (Cel_ID). The user terminals (UT) of the mobile telephone network communicate with the base stations BTS by means of a radio path. Base station controllers (BSCs) communicate, in turn, with both the GSM backbone circuit-switched network and the GPRS packet-switched network, of which only the GPRS system is described in greater detail.

The GPRS system connected to the GSM network comprises two almost independent functions, namely a gateway GPRS support node (GGSN) and a GPRS support serving node (SGSN). The GPRS network may comprise several gateway GPRS support nodes and GPRS support server nodes, and typically several GPRS support server nodes (SGSN) are connected to the gateway GPRS support node (GGSN). Both SGSN and GGSN nodes function as routers that understand the mobility of the mobile station and monitor the mobile system and the routing of the data packets to the mobile stations regardless of their location and the protocol used. The GPRS supporting serving node (SGSN) communicates with the mobile station UT via the mobile telephone network. The connection to the mobile telephone network (Gb interface) is typically constituted by means of the base station controller (BSC) and subsequently by means of a radio frequency connection constituted from the base transceiver station (BTS) with the station. mobile UT. The task of the GPRS Support Serving Node (SGSN) is to detect the mobile stations that are capable of GPRS connections within its service area, to transmit and receive the data packets from these mobile stations and to control the location of the mobile stations. existing in your service area. The subscriber relationship information is stored in a particular subscriber server (HSS).

The GPRS gateway support node (GGSN) functions as a gateway between the GPRS network and an external packet data network (PDN). External data networks can be, for example, the Internet, an X.25 network, or a private local area network. The GGSN can also be directly connected with a private company network, or with a host, for example as in the case of Figure 2, with a PoC server system by means of a SIP proxy. The data packets transferred according to the GPRS protocol between the GPRS gateway support node (GGSN) and with the GPRS support server node (SGSN) are always what is designated as encapsulated GTP (GPRS Tunnel Transmission Protocol) . This means that a data packet is encapsulated in another data packet when it is transferred from one end of the tunnel to the other. The gateway GPRS support node (GGSN) also contains the PDP (Packet Data Protocol) addresses and routing information, ie the SGSN addresses, of the GPRS mobile stations. The address and routing information of the GPRS gateway support node (GGSN) also contains the PDP (Packet Data Protocol), that is the SGSN addresses, of the GPRS mobile stations. The routing information is thus used to link the data packets between the external data network and the GPRS supporting serving node (SGSN). The GPRS gateway support node (GGSN) also unpacks the received data packets from the user terminal UT and transmits them to an appropriate data network. The backbone between the GPRS gateway support node (GGSN) and the GPRS support server node (SGSN) is a network using the IP protocol (IPv4 / IPv6).

Said GSM / GPRS network known per se provides the PoC service with an IP-based telecommunications connection on the top of which the PoC service itself is implemented as data transfer between the server system and the PoC client applications of the terminals. For the transmission of PoC service data, the GGSN is connected to the PoC server system by means of a SIP proxy so that the SIP proxy controls the VoIP packets between the terminals and the PoC server system. Likewise, Figure 2 shows an application server (ASR) according to the invention, which comprises the connection interfaces with both the SIP proxy and the GPRS HSS register. The application server (ASR) can be a separate server, or its functions can be implemented as part of one of the servers of the PoC server system, but to illustrate the invention in this context, the functions of the application server according to the invention are described by means of a separate ASR server.

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One of the tasks of the application server (ASR) is, in connection with the PoC service, to control the establishment of a site-related PoC group and to verify the placement of the terminals of a PoC group of the indicated type. The system comprises a memory medium, in connection with either the application server (ASR) or, for example, a subscriber database in which the specifications of the PoC groups related to the site are stored. Thus, the terminal user can use a method according to the invention and store in its database the PoC server system, for example in a register (REG) operated by the subscriber and group management function (SGMF), a SGMF group specification comprising information about at least the terminals of the group, the reference point of the site relationship (for example the site of the terminal expressing a connection establishment request and the area determined from the reference point, within which area the members of the PoC group can be activated or kept active within the group These specifications may also be transmitted in connection with the connection establishment request.

Thus, when a terminal belonging to a group or establishing a group transmits a request to establish a connection with the group in question, the task of the application server (ASR) is to control the given specifications of the PoC group related to the site and, on the basis of these specifications, also control the location of the other terminals of the group, determined in the connection establishment request, relative to the benchmark offered. The terminals determined in the application that are located in the area according to the specifications, can be activated to participate in the PoC group, so that the application server (ASR) instructs the PoC server to carry out the establishment of the connection.

In many cases, the reference point used is, most preferably, the terminal that establishes a group (a subscriber, that is, the terminal that transmits the PoC connection establishment request), more precisely the position of this terminal. Another terminal in the group can also be used as a reference point. In these cases, the reference point is removable; in other words, when the terminal adopts a new location, the location of the other members of the group is controlled in relation to this terminal. If any of the terminals in the group is no longer located within the area according to the specification, it is removed from the active group. However, the application server (ASR) reserves the PoC group information of the terminal subscriber, so that if the terminal returns to the determined activity area, the terminal is reactivated to participate in the PoC group.

The reference point and the area of ​​activity to be established around it can also be a fixed geographical area (for example a large city, a sector of a large city, or a distance of 10 km from the point. reference) in which case existing PoC group terminals within the area can be activated to participate in the PoC group call. Therefore, the area is determined, as a maximum preference, as the mobile phone network cells that cover the area, so that the terminals of the PoC group that communicate with the base transceiver stations of the cells can be activated to participate. in the PoC group call. Also in the case of a movable reference point described above, the determination of the area of ​​activity is, most preferably, linked to the cells of the mobile system. The determination of the area of ​​activity can, for example, include all cells of the mobile system with a radius of 10 km from the reference point.

The location of a terminal can be, in itself, determined with several different procedures, among which procedures for updating the location, the aforementioned cell-based positioning (COO (Cell of Origin)) is the one applicable as the highest preference to the procedure. according to the invention, because the location of the terminal needs to be determined particularly precisely, but the precision of a specific cell is typically sufficient to apply the invention. Also, the specific cell location information (cell identifier, Cell_ID) is directly applicable to a PoC system. The location can also be determined based on different triangulation procedures (EOTD, Enhanced Observed Time Difference; TOA, Time of Arrival), in which case the signaling of the mobile station is used, or using satellite positioning, such as the GPS system (Global Positioning System), but the location information produced by these positioning methods it must also be processed separately, for example within an application server (ASR), in order to be usable to apply the invention.

Determination of the specific cell of the activity area can also be used in such a way that a terminal located at the edges of the activity area receives a warning about the proximity of the edge of the activity area. In other words, if an active terminal of the PoC group is located within the outermost cell area of ​​the activity area, an indication of this can be transmitted to the terminal and displayed on the terminal screen, for example as an exclamation mark. or other warning. The terminal may also comprise means for indicating the direction to the activity area, the means comprising a cartographic application based on the positioning information or a pointer based on a built-in compass. In this case, if an active terminal is close to an activity edge, or if the terminal has left the activity area, the user of the terminal can be warned, by means of these direction signaling means, about, in which address is the area of ​​activity.

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The PoC server system can also comprise what is called a presence server (PS), which attends to the collection of the ownership of the terminals, the presence and location information of the different networks. The presence information (presences) of the other terminals can be transmitted from the presence server to the terminal. In the previously described establishment of a location-related PoC group, the presence information can be applied in such a way that the taking into account of the location relationship in the activation of a terminal belonging to the group is linked to the presence profile in the terminal in each specific case. Thus, the application server can be offered a specification according to which the location relationship is in use on a given terminal, for example when the terminal has been pinned to a rendezvous profile, while it is not applied to other profiles. of presence the relationship of location.

Likewise, the presence information can be used to transmit information to the other members of the group by activating a terminal of a PoC group or deactivating a terminal with respect to a PoC group; so that the presence information is transmitted to the other members of the group, for example as a data text message or as an indication of the image displayed on the terminal screen. The SGMF function of the PoC system can be used to find group members and to maintain groups and their statuses.

The following describes the method according to the invention and the operation of the application server (ASR) in a case where a predetermined site-related PoC group is activated. The starting point in this example is a situation where the PoC group has been assigned specifications in advance that have been stored in the PoC server system. In this case, the PoC group specifications fix the location of the terminal by submitting a connection establishment request (subscriber A) as the reference point for the location relationship, and an activity area to activate the members of the PoC group defined around from the reference point, covering the area of ​​activity the cells of the mobile telephony network located within a radius of 10 km from the subscriber A.

Suppose that the terminals UT1, UT2 and UT3 shown in Figure 2 belong to the same PoC group but that they are all located in different cells, in other words they communicate with different base transceiver stations BTS1, BTS2, BTS3. Initially, the establishment of a PoC session is carried out with the terminal UT1 (subscriber A) pressing a tangential button located on the terminal, so that the terminal transmits a service request to the network. The station network RAN, controlled by the GPRS supporting serving node SGSN, allocates an uplink transmission path for the connection, for example a dedicated packet data channel and a time slot frame, and the GPRS network generates the GPRS context required in connection. The GPRS network guides the PoC session establishment request to a SIP proxy, who then forwards it to the PoC server system.

After this, the PoC server system then guides the request to the application server ASR (or in practice to the application server functionality of the PoC server system), which then establishes a connection with the HSS of the database and retrieves the location of terminal UT1 with a precision of one cell (Cell_ID). At the same time, the ASR application server controls in the database the cell identifiers of the cells of the mobile phone network within a radius of 10 km from the subscriber A, that is, the current activity area of ​​the PoC group . The application server ASR then examines the locations of the terminals UT1, UT3 of the other users (subscribers B) of the group determined in the request. The current cell identifiers (Cell_ID) of subscribers B are checked and compared with the cell identifiers of the activity area. In response to the cell identifiers of the terminals UT2, UT3 belonging to the determined activity area, the PoC server system also presents the PoC group call request to the terminals UT2 and UT3.

When a PoC group call has been established between terminals UT1, UT2 and UT3, the application server ASR continues to verify the location information. If the terminal UT1 of subscriber A adopts a new location, for example within the neighboring cell, a new area of ​​activity of the PoC group and the cells included in it is defined, after which the identifiers of the cards of the other members of the group UT2, UT3 are rechecked and compared with the cell identifiers of the redefined activity area. In the same way, changes to the location information of subscribers B are also updated. If one of the terminals UT2, UT3 of subscribers B is no longer located in the activity area, due to movements, either subscriber A or subscriber B, it is removed from the active PoC group. The ASR application server, however, retains the PoC group information of this terminal user, and if the terminal returns to the determined activity area, the terminal is reactivated to participate in the PoC group.

The above arrangement works in a case where all the terminals of the PoC group are under the same network operator. In order to receive the required location information on the terminals that are under different network operators, an interface must be provided that provides the location information between the networks of different operators, for example between the HSS of the databases. Alternatively, a separate network element shared by different network operators may be used, in which case this network element would comprise only said location information, for example.

The method according to some embodiments of the invention can be illustrated with a simplified signaling diagram according to Figure 3, which shows the start of a location-related PoC session between two terminals UT1 and UT2. For illustrative purposes, Figure 3 generalizes for example

ES 2 294 643 T3 the RAN, GPRS and PoC functional entities in separate functions without going into their internal data transmission or signaling in greater detail, insofar as these are known per se by those skilled in the art and are not relevant for understanding the invention. Figure 3 also shows the signaling related to the establishment of a PoC session in a simplified way.

In Figure 3, the terminal UT1 functions as subscriber A that carries out the establishment of a PoC session by pressing a tangential button (300). The terminal UT1 transmits a service request 302 to the network, which expresses that the terminal UT1 needs both an uplink radio path and a GPRS context for a PoC session. The GPRS association request is guided from the RAN station network below to the GPRS network (304). The GPRS network generates, in a way known per se, a GPRS context (306) required in the connection, the context being used by means of a dedicated terminal (308) of data packets assigned for the network connection of RAN stations .

The establishment of the GPRS context and the dedicated packet data channel is indicated to the terminal UT1 as a signal that the PoC channel is open so that the subscriber of the terminal UT1 can start speaking. The terminal UT1 transmits the first RTP message (310), which comprises the group call identifier of the terminal UT1 and the first RTP voice packets of the VoIP. The station network RAN1 guides the PoC session establishment request to a GPRS network (312), which then guides said request to a SIP proxy (314) which, in turn, then transmits the request to establish a connection. PoC session to a PoC server system (316).

The PoC server system then guides the PoC session establishment request to an ASR application server (318), which controls in the database HSS the cell identifier of the terminal UT1 and the cell identifiers included in the area current activity (320). The application server ASR then verifies in the database the identifiers of the IDs of the terminals UT2, UT3 of the subscribers B determined in the request and compares them (322) with the identifiers of the IDs of the area of ​​activity. If it is observed that the cell identifiers of the terminals UT2, UT3 belong to the determined activity area, the ASR application server transmits information about it to a PoC server system (324), which then directs the group call request PoC to terminals UT2, UT3 (330, 332) by means of a GPRS network (326) and a network of RAN stations (328).

The best way to implement the functionality of the application server according to the invention is as a program code stored in the memory of the server, so that the server can be a separate server, or the functionalities of the application server can be implemented. as part of one of the servers in the PoC server system. Said program code comprises at least one computer program code to functionally connect the server unit (ASR) with at least one server (PoC) that controls the voice communication of the group; computer program code for storing the location-related specifications for a voice communication group to be established, the specifications comprising a predetermined maximum distance from a reference point, set between the members of the group; and a computer program code to control the establishment of an IP-based voice communication group between at least two of the terminals, such that the activation of the group members requires the location within the activity area determined by the maximum distance.

It should be obvious to a person skilled in the art that, as technology advances, the basic idea of ​​the invention can be implemented in a plurality of ways. The invention and its embodiments are not limited to the examples set forth but may vary within the scope of the claims.