Optimizing call setup latency for geographically dense groups

Background Technique of the Present Invention 1. Field The present invention generally relates to reducing communication latency. In particular, the present invention relates to optimizing call latency in a group calling communication system when participants are geographically co-located in a small number of sectors in a radio access network (RAN).

2. Background Technological advances have brought about smaller and more powerful personal computing devices. For example, a variety of wireless computing devices such as mobile wireless phones, laptops, personal digital assistants (PDAs), and paging devices, each of which is small, lightweight, and easier to carry by the user. Portable personal computing devices currently exist. A wireless device is any device that can communicate with other devices without having to physically connect to them. Most wireless devices communicate with each other over radio frequencies.

More specifically, for example, a mobile radiotelephone further includes a mobile phone that communicates voice and data packets over a wireless network. In addition, many such mobile phones are being manufactured with a relatively large increase in computing power, which is why they are becoming equal to small personal computers and portable PDAs.

However, these smaller and more powerful personal computing devices are generally severely resource-constrained. For example, screen dimensions, available memory, and amount of file system space, amount of I / O capacity, and processing power may each be limited by the small size of the device. Due to tight resource constraints, for example, maintaining a limited size and the amount of software applications and other information that exists for such remote personal computing equipment (eg, client devices) is often common. desirable.

Some of the personal computing devices utilize one application programming interface (API), often referred to as the run-time environment and software platform, or multiple application programming interfaces (APIs). And they are installed on their local computer platform, and they simplify the operation of such devices, for example by providing generalized calls to specific resources of the device. Used to convert. An API is a set of routines used by an application program to direct the execution of procedures used by a computer's operating system.

In addition, some APIs are also known to provide software developers with the ability to create fully executable software applications on such devices. In addition, some of such APIs are between the system software and software applications of a computing device, and the computing device system software and software applications are capable of computing the computing device, which is a particular computing device. It is known to be arranged to work so that it can be used by software applications without requiring the software developer to have the ingu device system source code. In addition, some APIs have been found to use secure cryptographic information to provide a mechanism for secure communication between such personal devices (ie clients) and remote devices (ie servers). Has been done.

Examples of such APIs (some of which are described in more detail below) are the Binary Runtime Environment for Wireless, developed by Qualcom, San Diego, California. Binary Runtime Environment for Wireless^(R)) (BREW^(R)) (Note: The superscript (R) represents the letter with "R" in the circle, the same shall apply hereinafter). BREW^(R)Can work with the operating system of a computing device (eg, a wireless cell phone) and, among other features, can provide an interface to hardware features specifically found on personal computing devices. it can. BREW^(R)In addition, BREW^(R)These interfaces can be provided on such personal computing devices at a relatively low cost, with respect to the price paid by the consumer for the device containing the API, and with respect to the demand for equipment resources. BREW^(R)Additional mechanisms include its end-to-end software distribution platform, which offers various benefits to wireless service operators, software developers, and consumers of computing equipment. At least one such currently available end-to-end software distribution platform contains logic distributed on a server-client architecture. Here, the server performs, for example, billing, security, and application distribution functions. The client then performs, for example, application execution, security and user interface functions.

Mobile communication devices (eg, radiotelephones) may include built-in input devices (eg, keypads) to allow users to enter alpha-numeric data. Due to the size limitation of such mobile devices, input devices are often relatively small. It may be difficult and / or slow for the average user to use.

The above description of the relevant art is merely an overview of wireless devices, and some of the known uses of the API, and BREW that can be used in various embodiments of the invention.^(R)Intended to be provided as an introduction to the platform. However, the invention should not be construed as being restricted to a particular physical configuration, implementation, operating platform or environment.

In group call communication systems, reducing latency is an important design goal that directly transforms into end-user customer satisfaction and usefulness. Some examples of latency sources or contributors in wireless networks follow. Channel allocation latency is a delay in allocating and initializing a traffic channel for a user's communication needs. Paging latency is a delay caused while waiting for a user's mobile device to respond to a page in the appropriate paging channel slot. Transmission over the radio, where calls occur, move, and are received across the communication infrastructure, is another source of latency.

In addition to these types of delays, there are additional delays that can occur in the group call communication server. Some examples of server delays are user request processing and server component communication.

In a Push to Talk (PTT) system, all different types of delays contribute to PTT latency. The PTT wait time is between the time when the user requests the right to speak by pressing the PTT button and the time when the user receives confirmation from the PTT application server that the call has been established and the right to speak is available. Is late. With the exception of paging latency, the delays described above further contribute to interterminal media latency. It is the delay between the time when the caller starts speaking and the time when the goal actually hears the caller's voice.

Therefore, it is desirable and advantageous to provide a way to reduce latency in group communication systems.

Typical embodiments of the present invention are directed to methods and systems for optimizing call setup latency for geographically dense groups.

Therefore, one embodiment of the invention can include a method of optimizing call setup latency, including: Updating client location information using at least one application server to provide the latest location while at least one client is moving from one sector to another; Identifying and updating parameters containing location update information that uniquely identifies the sector to which at least one client is receiving communication services; Determining at least one geographically dense call group; Choosing at least one designated responder to answer at least one call group; Computing client clusters with relevant parameters; If at least one client per cluster is selected as the designated answerer for that cluster, and the server needs to set up geographically dense group calls, a random number will appear in the call setup message. Included corresponding to the designated responder for that group.

Another embodiment of the invention may include a system for optimizing call setup latency, including: With logic configured to update client location information using at least one application server to provide the latest location while at least one client is moving from one sector to another. ; With logic configured to identify and update parameters containing location update information that uniquely identifies the sector in which at least one client is receiving communication services; With logic configured to determine at least one geographically dense call group; With logic configured to choose at least one designated answerer to answer at least one call group; With logic configured to compute a cluster of clients with relevant parameters; Logic configured to select at least one client per cluster as the specified response to that cluster, and random numbers when the server needs to set up geographically dense group calls. , In the call setup message, is included corresponding to the designated responder for that group.

Another embodiment of the invention is a method in a wireless communication system, which may include a computer-readable medium embodying a method including: Updating client location information using at least one application server to provide the latest location while at least one client is moving from one sector to another; Identifying and updating parameters containing location update information that uniquely identifies the sector in which at least one client is receiving communication services; Determining at least one geographically dense call group; Choosing at least one designated answerer to answer at least one call group; Computing a cluster of clients with relevant parameters; Select at least one client per cluster as the designated answerer for that cluster, and when the server needs to set up geographically dense group calls, a random number will be given in the call setup message. Included corresponding to the designated responder to the group.

Implementation of the invention, as it will be better understood by reference to the detailed description below, when contemplating in connection with the accompanying drawings set forth below, not as a limitation of the invention. A more complete understanding of the morphology and many of its associated benefits will be readily available.

<figref num="1">It is a typical diagram of a wireless network architecture that supports client devices and servers according to at least one embodiment of the invention.</figref><figref num="2">It is a more detailed and typical diagram of a wireless network architecture that supports client devices and servers according to at least one embodiment of the invention.</figref><figref num="3">It is a typical figure which shows implosion of ACK.</figref><figref num="4">FIG. 6 is a typical diagram showing a method according to at least one embodiment of the invention.</figref>

Detailed explanation

Various embodiments of the invention are disclosed in the relevant drawings and the following description towards a particular embodiment of the invention. Alternative embodiments may be devised without departing from the spirit and scope of the invention. Moreover, well-known elements of the invention will not be explained or omitted in detail so as not to obscure the details associated with the invention.

The word "exemplary" is used herein as intended to be "provided as an example, instance, or illustration." As "typical," any embodiment described herein cannot necessarily be construed as preferred or advantageous over other embodiments. Similarly, the term "invention embodiment" does not need to include features, advantages or modes of operation in which all embodiments of the invention are described.

In addition, many embodiments are described in terms of sequences of actions performed, for example, by elements of computing equipment. It has been recognized that specific circuits (eg, application specific integrated circuits (ASICs)) can perform the various actions described herein by program instructions executed by one or more processors, or by a combination of both. Will be. In addition, these sequences of actions described herein are complete on any form of computer-readable storage medium in which the corresponding set of computer instructions that cause the associated processor to perform the functions described herein at run time is stored therein. It can be considered that it is embodied in. Thus, the various aspects of the invention can be embodied in many different forms, all of which are considered to be within the scope of the claimed subject matter. Further, for each of the embodiments described herein, the corresponding embodiment of any such embodiment may be, for example, as "logic configured to" performing the described action or function. Can be explained here.

One or more embodiments of the invention can be used in connection with a run-time environment (eg, API) running on a computing device. One such runtime environment (API) is the Binary Runtime Environment for Wireless described earlier.^(R)) (BREW^(R)) Software. However, one or more embodiments of the invention can be used, for example, by other types of run-time environments (APIs) that operate to control the execution of applications on a wireless client computing device.

The techniques and mechanisms described below are aimed at implementing the components and methods of mobile electronics that interact with an input device via a standard earphone / microphone connector. In general, mobile electronics include an interface that supports data transfer between the mobile electronics and the input device via a standard earphone / microphone connector. This interface can be implemented in hardware and / or software. Specific implementations and embodiments of this general concept are described below.

FIG. 1 shows a block diagram of one typical embodiment of wireless system 100 according to at least one embodiment of the invention. System 100 selectively sends software applications and components to wireless devices via a wireless communication portal to wireless network 104, or other data access, at least one application download. It includes a client device such as a mobile phone 102 that communicates over a wireless network 104 with an application download server (ADS) 106. As shown in Figure 1, the wireless (client) device can be a mobile phone 102, a personal digital assistant 108, a pager 110 (which is shown here as a bidirectional text pager), or a separate computer with a wireless communication entrance. There could be a platform 112 and so on. This separate computer platform 112 may be fixed (eg desktop) or mobile (eg laptop).

Accordingly, various embodiments of the invention have wireless communication capabilities including, without limitation, wireless modems, PCMCIA cards, personal computers, access terminals, telephones or any combination thereof, or sub-combination. It can be implemented in any form of client device or wireless device that includes a wireless communication entrance.

The Application Download Server (ADS) 106 is shown here on network 116, which has other computer elements that communicate with wireless network 104. There may be a stand-alone server 122. Each server can then provide individual services and processes across the wireless network 104 to client devices 102, 108, 110 and 112. In addition, there is preferably at least one stored application database 118 that holds software applications that can be downloaded by wireless devices 102, 108, 110 and 112. However, those skilled in the art will fully understand that the configuration shown in Figure 1 is simply typical. Accordingly, an embodiment of the invention is one or more capable of performing all the described functions, respectively, and may include all required hardware and software, or may simply include selected functions. Servers can be included. Moreover, not all of the indicated elements (eg, pager 110, ADS106, database 118, etc.) are necessarily used in all the different embodiments of the invention that can be implemented.

FIG. 2 shows a more complete block diagram of System 100, which includes the interrelationships of the components of the wireless network 104 and the elements of a typical embodiment of the invention. System 100 is simply typical where remote client devices such as wireless client computing devices 102, 108, 110 and 112 cross space, between and within each other, and / or Includes, without limitation, any system that allows communication between and within components connected through wireless network 104, including wireless network carriers and / or servers. Can be done. The application download server 106 and the stored application database 118, along with other servers such as the AD display server 130 used to provide cellular long-distance communication services, are connected to the Internet, secure LAN, WAN or other. Communicate with carrier networks through data links such as networks. In the embodiments shown, the server 120 can include an application download server 106, an AD dispatch server 130 and a stored application database 118. The application download server 106, the server 130 and the stored application database 118 are shown as independent devices in this embodiment. However, these devices can also be integrated into one common server. Alternatively, one or more functions may be distributed across multiple devices, as will be appreciated by those skilled in the art.

The carrier network 200 controls the messages (generally sent as data packets) sent to the Message Services Controller (MSC) 202. The carrier network 200 communicates with the MSC 202 over the network, the Internet, and / or the public switched telephone network (PSTN). Generally, a network between the carrier network 200 and the MSC 202, or an internet connection, transfers data, and the PSTN transfers voice information. The MSC 202 can be connected to multiple Base Stations (BTS) 204. In a manner similar to carrier networks, the MSC 202 is generally connected to the BTS 204 via the network, the Internet and / or the PSTN for data transfer and / or voice information. BTS The 204 is a client like the mobile phone 102 by short message service (SMS), UDP datagrams, or other over-the-air (OTA) methods known in the art. Data messages can be broadcast wirelessly to the device.

A client device such as the mobile phone 102 (here a wireless client computing device) receives software applications and / or commands sent from the application download server 106, AD dispatch server 130, and / or server 120. You have a computer platform 206 that you can run. The computer platform 206 can include an application specific integrated circuit (ASIC) 208, or other processor, microprocessor, logic circuit, or other data processing unit. The ASIC208 or other processor runs the API210 layer that connects to any resident program in memory 212 of the wireless device. The memory 212 can consist of read-only memory or random access memory (RAM and ROM), EEPROM, flash card, or any memory common to computer platforms. Computer platform 206 also includes a local database 214 that can hold applications that are not actively used in memory 212. The local database 214 is generally a flash memory cell, but can be any auxiliary storage device known to those skilled in the art such as magnetic media, EPROMs, optical media, tapes, soft yet hard disks, etc. ..

A wireless client computing device such as the mobile phone 102 has one or more software applications such as games, news, stock monitors, etc. that are installed on it or otherwise download. There is. For example, the mobile phone 102 can receive one or more software applications downloaded from the application download server 106. Software applications may be stored on the local database 214 when not in use. The mobile phone 102 or other wireless computing device is a resident application stored on the local database 214 to run on the API 210 when desired by the user or when called by another API. Can be uploaded to memory 212.

As used herein, a "client device," "wireless device," or "client computing device" includes, for example, one or more processing circuits that execute resident configured logic. Here, such computing devices include, for example, microprocessors, digital signal processors (DSPs), microcontrollers, portable wireless phones, personal digital assistants (PDAs), and paging devices, or hardware, software, and /. Alternatively, it is directed to an ADS that communicates between a client device and a server and contains any suitable combination of firmware, including at least a processor and logic configured to perform the operations described herein. Client computing devices can be serviced by at least one remote server for at least such ADS. Some examples of "wireless computing devices" that can be used according to various embodiments of the invention are mobile phones or other wireless communication units, PDAs, laptops, paging devices, navigation devices (eg GPS-based). Systems), handheld game consoles, music or video content download units, and other similar wireless communication devices.

Wireless communication between the client device 102 and BTS 204 is code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), global mobile communication system (GSM), or wireless communication. It can be based on various technologies such as networks or other protocols that can be used in data communication networks. Data communication is generally between client devices 102, BTS 204, and MSC 202. The MSC 202 can connect to multiple data networks such as the carrier network 200, PSTN, Internet, virtual private networks, etc., thereby allowing client device access for a wider communication network. As described above, in addition to voice transmission, data can be transmitted to client devices via SMS or other OTA methods known in the art.

Public safety and disaster recovery scenarios require effective and efficient communication between large sets of mobile devices. The latency caused during call setup for these large groups is as important a measure as efficiency in the transmission medium between these devices.

Group communication systems (eg, push-to-talk (PTT) systems) are generally meant to be instant access, always on, and guaranteed talk permit. Attempts to provide many features to the end user, including. Instant access refers to providing the user's perception that the group communication system provides instant and continuous access to the group communication system. Feedback should be present regarding the success or failure of any request made by the user to the group communications service. Always on should provide the recognition that the group communication system is readily available at all times. It is desirable for the user to have a certain degree of connectivity for group communication while the user requests it. Guaranteed talk permit) ensures that the user's audio is delivered to at least one of the specified goals. The group communication system should also confirm the goal of participation in the group communication call before granting the caller permission to make the call.

In addition to the large number of participants in these group calls, new challenges arise when participants are geographically co-located in a small number of sectors in a radio access network (RAN). The potential for increased collisions on the access channel due to an acknowledged gment (ACK) implosion is shown in Figure 3 when a large number of devices attempt to respond simultaneously.

Figure 3 shows one example of an ACK explosion scenario. The application server 300 sends a call setup message 302 to the base station transceiver (BTS) 304. The BTS 304 broadcasts call setup message 305 to a group of client devices (handsets 306, 308, 310, 312 and 314 shown in FIG. 3). The number of conflicts on the access channel increases when all client devices attempt to respond simultaneously or almost simultaneously (ACK 315 for accepting calls).

The phenomenon shown in FIG. 3 causes an increase in the call setting time because the response to the call setting message is delayed. During call setup for geographically dense and multicast groups, many access probe collisions attempt to respond to call requests simultaneously, with multiple targets registered in the same sector. Occurs. These conflicts cause an increase in call setup time. The application layer method proposed here eliminates the collision probability as a possibility by letting the application server select a designated responder for these large group calls.

Performing an identifier disjunction after a given responder has been selected (eg, one per cluster) means that there is no particular order for the response. If one device understands that the identifier was used as part of the calculation of the bit sequence in the outgoing message, it will respond immediately. Other devices will refrain from responding to them.

Geographically dense calls can have multiple clusters (eg, one hotspot or cluster per collision domain or BTS). In this embodiment, we proposed that the server select exactly one designated responder per cluster. The server will be able to select multiple responders per cluster. However, this will increase the likelihood of conflict when those responders respond to messages sent by the server. This is not necessary as the outgoing message will be sent to all these clusters (addressing the join of the specified responders) as long as you order the specified responders to different clusters.

FIG. 4 shows a typical method of implementing one embodiment of the present invention to optimize call setup latency. Client location information is updated using at least one application server to provide the latest location while the client is moving from one sector to another (400). The parameters are identified and updated, including up-to-date location information that uniquely identifies the sector in which the client is receiving communication services (402). At least one geographically dense call group is determined (404). At least one designated answerer is chosen to answer the call group (406). A cluster of clients with relevant parameters is calculated (408). One client per cluster is selected as the designated responder for that cluster. Then, when the server needs to set up a geographically dense group call, a random number is included corresponding to the designated responder for that group in the call setup message (410).

However, choosing a single responder may not be the best choice for fault tolerance reasons, as large group calls can span multiple sectors. The server can choose multiple designated responders without increasing the size of the call setup message.

In one typical scenario, the server chooses exactly one designated responder per cluster. A cluster is defined as a set of devices receiving communication services from a single BTS (or devices in the same collision area). Therefore, the total number of responders depends on how many dense clusters (or hotspots) exist for one specified group call.

The server maintains state for a predefined set of groups that may be geographically dense. Those skilled in the art will fully understand that multicast groups will also benefit from the schemes and similar behaviors defined here.

This is because the "identifier" contained in the server message plays a role in eliminating conflicts in the response. The method is independent of addressing schemes (eg multicast groups with multicast IP addresses) and forwarding mechanisms (eg unicast or multicast).

The client constantly updates the location information by the application server while moving from one sector to another. The location update includes parameters that help the client uniquely identify the sector receiving the CDMA service (eg, system ID (SID), network ID (NID), carrier identifier, pilot PN offset).

The client also contains the n-bit random numbers it produces. As explained later, a larger n results in a lower collision probability. However, since the server includes this n-bit number in the outgoing call request, a larger n will lead to a larger call notification message. For example, one value of n that can be selected is 16. Some of the following reasons are used to select the value of n.

For reasons such as processor design (operation efficiency on PC / server / device)), the value of n should be a multiple of 8 bits. The probability that at least two devices in a cluster (of size k) will have the same identifier decreases exponentially with a value of n and can be approximated by the following expression:

P (k, n) = 1-e ^ (-(k ^ 2) / (2 * 2 ^ n))) For n = 8 and reasonably sized clusters (eg k = 20), the probability that two devices will have the same ID is 1-(e ^ (-(20 ^ 2) / (2 * (2 ^)). 8)))) = 0.542166638. For n = 16 and the same cluster size, the probabilities are 1-(e ^ (-(20 ^ 2) / (2 * (2 ^ 16)))) = 0.00304710593, which is small enough. The client can additionally include the strength of the pilot as an indication of physical proximity to the base station. It should be noted that physical proximity may not be representative of access probe signal quality, as access probe power is normalized to take this into account.

The server maintains state (SID, NID, random #) for all geographically dense, predefined members of the group. For each group, the server computes a cluster of clients with the same &lt;SID, NID&gt; pair and selects exactly one client per cluster as the designated responder to that cluster.

The &lt;SID, NID&gt; pair is used by the server to identify the cluster (or hotspot). Multiple devices reporting the same &lt;SID, NID&gt; are expected to be geographically close or close together, so they can be assumed to be in the same cluster. After identifying these clusters and the designated responders for these clusters, the server uses the random numbers notified by the designated responders in the OR operation.

The server then computes the logical OR of the random numbers that correspond to the specified responders in the m largest cluster. The following example is provided as an example.

Suppose the server receives the next &lt;SID, NID, random #&gt; from 10 devices.

1. &lt;1,1,4324&gt; 2. &lt;1,2,6553&gt; 3. &lt;2,1,7722&gt; 4. &lt;3,1,46536&gt; 5. &lt;1,1,25232&gt; 6. &lt;1,1,43456&gt; 7. &lt;4,1,5653&gt; 8. &lt;1,1,63434&gt; 9. &lt;1,1,34236&gt; Ten. &lt;1,1,23423&gt; The server presumes that &lt;1,1&gt; is a hotspot and selects the designated responder with device number 6. In addition, for reliability, devices that signal different &lt;SID, NID&gt; pairs are included in the OR operation. And the final identifier is: 6553 (from device 2) &lt;Logical OR&gt; 7722 (from device 3) &lt;Logical OR&gt; 43456 (from device 6) 0001100110011001 OR 0001111000101010 OR 1010100111000000 = 1011111111111011 = 49147 (decimal) When device 2 gets this identifier (49147) in the message, it does the following operation: 6553 AND 49147, which calculates 6553. Then proceed and respond. However, from all devices in cluster &lt;1,1&gt;, only device 6 gets this privilege.

43456 AND 49147 = 43456 For device 9, 34236 AND 49147 = 34232, which is not the same as 34236, so it does not respond.

The reason for choosing the largest m clusters to provide collision resistance follows.

S_sectorRepresents the number of clients in the sector.

S_denseRepresents an access terminal that belongs to a geographically dense group.

S_sparseIs the remaining access terminal S_sector-S_denseRepresents.

A large cluster means that there are many access terminals (ATs) that are members of a single geographically dense group belonging to the same sector (collision area). That is, S_dense/ S_sectorIs almost 1.

By carefully choosing the specified responder, the server will be S_denseWe have already minimized the probability that the access probes of the access terminals belonging to will collide with each other.

Here, the conflict that matters to us is S_sparseIt is a conflict between the members of. This probability is S_sparseIncreases with increasing, and S_sparseIs smaller when is small. This is S_sparseIf is small, it suggests that the collision random probability will be small.

S_sparseAs the number decreases, the probability of random collision decreases.

=&gt; S_sparseIs small =&gt; S_sector-S_denseIs small.

If Ssector = constant = k, then S_denseShould be as large as possible.

The value of m should be small. A situation where m = 1 means that only one specified responder is selected from a set of clusters, and if this device is close to the cell edge, a server message destined for that device. May have to be retransmitted multiple times. And it causes a delay. The value of m is flexible, and if there is a considerable amount of certainty that the message will reach a set of m responders (eg, based on pilot intensity or other estimates). m can be smaller. This value can be optimized and is subjective based on carrier policy. To make this step less computationally expensive, the choices may be random, or may be based on pilot strength measurements, or some other heuristic.

When a server needs to set up a geographically dense group call, it includes a random number corresponding to the specified responder for that group in the call setup (notification) message.

Random numbers are used by the device to present a unique number to the server. Based on that, the server calculates the identifier used by the device to identify whether it should respond. Earlier examples of &lt;SID, NID, random #&gt; sent by different devices are directed to this concept.

When the target receives the call setup message, they calculate the AND operation on the number included in the notification message and the random number generated by the client during the registration procedure. If the expression below is true, the client goes ahead and responds to the notification at the application layer with no extra delay.

REG_RAND &amp;&amp; ANNOUNCE_IDENT == REG_RAND If the above conditions are not met, the client is waiting for a deterministic amount of time equal to the transmission time of the access probe containing the response to the notification. Doing this leads to a significant reduction in the number of access conflicts between group call settings.

The arrangement of logical elements is for convenience of illustration only and should not be construed as a limitation of embodiments of the invention. As will be appreciated by those skilled in the art, the functionality of the logical elements described herein may be integrated into one element or distributed as desired among various hardware and software elements. You may.

Those skilled in the art will also recognize that software or firmware (or any combination thereof) may be used to implement the present invention.

One of ordinary skill in the art will recognize that there is no particular order in the performance and execution of the method-functional blocks intended or meant in the previous description. The previous methods described above can be used on their own or in any combination thereof to achieve the same objectives.

In a further embodiment, one of ordinary skill in the art will recognize that the previous method can be realized by executing a program embodied on a computer-readable medium such as the memory of a computer platform. Instructions can reside on the first, second, and third media of various types of signal carriers or data storage devices. The medium can include, for example, RAM accessible from or present in the client device and / or server. Instructions, whether contained in RAM, diskettes or other auxiliary storage media, are direct access storage device (DASD) storage devices (eg traditional "hard drives" or RAID arrays), magnetic tape, electronic. Read-only media (eg ROM or EEPROM), flash memory cards, optical storage devices (eg CD-ROM, WORM, DVD, digital optical tape), paper "punch" cards, or media for digital and analog transmission It can be stored on various machine-readable data storage media, such as other suitable data storage media including.

Previous descriptions of the disclosed embodiments are provided to allow any person skilled in the art to make or use the present invention. Various changes in those embodiments will be readily apparent to those skilled in the art. And the general rules defined herein can be applied to other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not intended to be limited to the embodiments presented herein and should be given the broadest scope consistent with the rules and novel features set forth herein.

Although the above disclosure shows an exemplary embodiment of the invention, various modifications and modifications may be made herein without departing from the scope of the invention as defined by the appended claims. It should be noted that it may not be possible. It is not necessary to perform the actions or steps of the claims of the method according to the embodiment of the invention described herein in any particular order. Further, the elements of the invention may be described in the singular, but if the limitation to the singular is not explicitly stated, the plural are conceivable.