JP2010541403A - Method and apparatus for transmitting multiple multicast communications over a wireless communications network - Google Patents

Abstract

An apparatus and method for allocating bandwidth for multicast communication in a wireless communication network. The base station allocates a certain bandwidth to handle multicast communication through the multicast communication channel. When a new multicast communication arrives, the base station allocates a predefined number of bandwidths to the multicast communication channel according to a predefined algorithm. The wireless device will monitor all slots in the multicast channel and discard all packets that do not belong to its call.
[Selection] Figure 3

Description

Background of the Invention

1. The present invention relates to communications in a wireless telecommunications system, and more specifically to multiple multicast communications in a wireless telecommunications system.

2. Description of Related Art In wireless telecommunications systems, push-to-talk (PTT) capabilities are prevalent among service sectors and consumers. PTT can support “dispatch” voice services that operate through a standard commercial wireless infrastructure. Standard commercial wireless infrastructures include Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Global System for Mobile Communications (GSM). In the dispatch model, communication between end points (end user devices) occurs in a virtual group, and one “speaker” voice is transmitted to one or more “listeners”. One example of this type of communication is commonly referred to as a dispatch call or simply a PTT call. A PTT call is a group instantiation that defines the characteristics of the call. A group is essentially defined by a member list and relationship information, such as a group name or group identifier. In the absence of a wireless multicast channel, each group is formed by a combination of individual point-to-point connections between each endpoint, and a PTT server manages the call. Each endpoint is also known as a client. Instead, when a group is reduced to two members and a PTT call is made from one member to another, the PTT call will be a direct call between these two members.

  FIG. 1 illustrates a prior art architecture 100 that supports PTT calls. The architecture involves the deployment of a single PTT server area in relation to the carrier's CDMA infrastructure and packet data network. Each area of the PTT server is deployed across a specific part of the carrier packet data network. A PTT server in the region routes traffic between one or more packet data service nodes (PDSN) in the carrier network. A communication device 102 that supports the PTT function communicates with a base station (BS) 104. Each BS 104 communicates with one or more base station transceivers (BTS) 114. Base station 104 communicates with high speed network 106 and PTT communications received from communication device 102 are routed through the base station 104 and network 106 to a packet data service node (PDSN). The PDSN communicates with a high speed network 106 and a network 108 of PTT servers connected to the PTT network 110. The PDSN forwards the PTT communication to the PTT server 112 in the PTT network 110.

  The PTT server 112 handles PTT communication between members of the PTT group. The PTT server 112 receives a PTT communication from one member and forwards the PTT communication to all members of the PTT group. PTT communications are often received as data packets from the network 110, and PTT communications sent by the PTT server 112 are also in the format of data packets. The packet data service node (PDSN) and the connected base station (BS) 104 then establish a dedicated traffic channel through the BTS 114 and send PTT communications to the receiving mobile client (PTT member) 102.

  FIG. 2 illustrates a communication tower 202 connected to the BS 104, which transmits radio signals during the coverage area in which several wireless devices 102 are located. BS 104 transmits a PTT call that is directed to two wireless devices 102. When a user initiates a PTT call that is directed to a member of the PTT group, the PTT server 112 determines the location of each member and forwards the PTT call to each member. When two receiving members of a PTT call are served by a single BS 104, the BS 104 establishes one communication channel for each wireless device. If there is another incoming PTT communication to a member of another PTT group in the same cell, the BS 104 needs to allocate resources to each of the other received PTT members, and additional resources for each of the other received PTT members Establish a traffic channel.

  To support each PTT communication, allocating resources for each PTT communication and establishing a traffic channel is an important part of the PTT communication system. In order to support multiple PTT calls, it is desirable to have a PTT communication system that can easily and efficiently manage resources.

  The apparatus and method described herein allows multiple multicast communications over a virtual multicast channel over a wireless communications network. In one embodiment, a method is provided for transmitting multiple multicast communications over a wireless communications network. In this method, a base station allocates a plurality of transmission slots for multicast communication according to a predetermined algorithm, and a base station receives a plurality of multicast communications from a server. According to an algorithm, a predetermined number of transmission slots are allocated to each multicast communication, and each multicast communication is transmitted to a plurality of wireless devices via a predetermined number of transmission slots in the multicast channel. Including.

  In another embodiment, an apparatus is provided for transmitting multiple multicast communications over a single multicast channel over a wireless communications network. The apparatus includes a network interface unit that receives multicast communication from a server, a radio interface unit that can establish multicast communication for a plurality of wireless communication devices, and a control unit. Each multicast communication is broadcast through a plurality of transmission slots, and the controller unit can assign a predetermined number of transmission slots to each multicast communication according to a predefined algorithm.

  Other advantages and features of the invention will become apparent after review of the following brief description of the drawings, detailed description of the invention and the claims.

FIG. 1 is a prior art architecture of a wireless communication network. FIG. 2 is a prior art base station that supports PTT calls to multiple wireless communication devices. FIG. 3 illustrates an embodiment of a base station supporting multicast PTT calls to multiple wireless communication devices. FIG. 4 illustrates a base station that supports multiple multicast PTT calls for multiple wireless communication devices. FIG. 5 is a block diagram of a base station supporting the present invention. FIG. 6 is a flowchart of a process of a base station according to the present invention.

Detailed Description of the Invention

  In this description, the terms “communication device”, “wireless device”, “wireless communication device”, “PTT communication device”, “handheld device”, “mobile device”, “mobile client”, “end user device”, And “handset” are used interchangeably. The terms “call” and “communication” are also used interchangeably, as are the terms “base station” and “base station server”. The term “application” as used herein is intended to include executable and non-executable software files, raw data, aggregated data, patches, and other code segments. The term “exemplary” means that the disclosed element or embodiment is illustrative only and does not indicate any preference of the user. Further, in this description, unless otherwise specified, the same number refers to the same element in several respects, and the articles “one” and “that” include multiple references.

  In summary, the system and method allows for efficient and flexible bandwidth usage for multicast communications. Multicast communication is supported by the broadcast multicast service (BCMCS). BCMCS enables optimal use of a broadband wireless network that distributes BCMCS content streams to one or more terminals in one or more regions of the operator network. To complement unicast that individually sends video content to subscribers (eg, video on demand), BCMCS provides simultaneous multimedia content transmission from a single source to multiple users. Unlike unicast, which is a one-to-one transmission of multimedia data, BCMCS streamlines air interface and network resources by pushing multimedia content to all terminals in the sector in a single virtual transmission. Use and reduce the cost of delivering content. Service providers do not have to dedicate all carriers to multicast. With BCMCS, unicast and multicast can coexist, service providers can multicast when events or programs require (eg, live sports events), and unicast services during periods of inactivity A carrier wave can be used. During the multicast, the same multimedia content is sent to users located in multiple sectors.

  BCMCS can support PTT communication. PTT communication is generally audio communication. However, data and video can also be broadcast during PTT communications. In order to better support PTT multicast communication, the BS 104 reserves slots used for PTT multicast communication, and the PTT server 112 is provided with a PTT multicast channel number. When a user turns on his wireless device 102, the wireless device 102 exchanges messages with the BS 104, and the wireless device 102 is registered with the BS 104 and the PTT server 112. After the wireless device is turned on, the wireless device monitors overhead messages broadcast by the BS 104. The overhead message contains information about the multicast channel, such as slot, data rate, channel number, etc. For multicast enabled wireless devices, the PTT server 112 sends a PTT multicast channel number to the wireless device 102. By listening to the overhead message from the BS 104, the wireless device 102 knows about the slot, data rate, channel number, etc. used for the PTT multicast channel. When the PTT user (caller) is ready to perform PTT communication, the wireless device 102 presses the PTT activation button, and the PTT request is made in this way. In response to the PTT request at wireless device 102, originating wireless device 102 sends a call request to PTT server 112. This call request is also known as a PTT dispatcher. The PTT server 112 receives the call request and processes the call request. The call request process identifies a PTT user, identifies a PTT group to which the PTT user belongs, identifies a member of this PTT group, and prepares an announcement call message sent to each member of the PTT group Including that.

  After the PTT server 112 sends an announcement call message, each announcement call message is received by the PDSN and forwarded to the BS 104 by the PDSN. BS 104 broadcasts the announcement call message to target receiver 102. If the mobile client that is the target receiver 102 is available, the mobile client 102 sends an accepted call message back to the PTT server 112. After receiving an acceptance call message from at least one mobile client 102, the PTT server 112 sends a floor permission message back to the originating mobile client 102. If there may be more than one target user 102 in the caller's PTT communication group and there is at least one available target mobile client 102, the PTT server 112 grants the caller the right to speak. . After receiving the floor permission message, the PTT requesting mobile client (outgoing wireless device) 102 can thus perform PTT communication.

  FIG. 3 is an illustration of a BS 104 that supports multicast communication for two wireless devices 402, 404. When a member of the PTT group uses the wireless device 102 to place a PTT call to other members of the own PTT group, the PTT server 112 receives the PTT communication and the two members have the same geographic location. Determine to be in the area and served by the same BS 104. The PTT server 112 determines that a multicast call may be used to send a PTT call to these two recipients 402, 404. The multicast call may then be sent over the multicast channel. Multicast channels are typically used when more than one recipient is in a particular geographic area. As such, instead of establishing multiple unicast calls, at least one multicast call can be established from one person to each recipient by establishing a slot service in the communication link. , BS 104 allocates a set of time slots (also known as transmission slots) from the PTT multicast channel for PTT calls, and both target wireless devices 402, 404 tune to the PTT multicast channel. The wireless devices 402, 404 must also be multicast enabled devices and generally need to monitor all slots in the PTT multicast channel after receiving the announcement message. Typically, the wireless device 402, 404 discards all packets that do not belong to a call that is directed to this wireless device. For example, the wireless devices 402, 404 can identify packets through a multicast IP address and port number embedded in each packet. The wireless device 402, 404 can know the multicast IP address and port used for the call from the announcement message from the PTT server 112 or some other message.

  FIG. 4 illustrates a BS 104 supporting two PTT calls that are broadcast to members of two different PTT groups. When a user belonging to the first PTT group makes a PTT group call to a member of the second group, the user of the first PTT group requests the right to speak and receives the right to speak from the PTT server 112. Send a PTT message as if it were the calling user. The PTT server 112 receives the PTT message and identifies a second group of PTT members. The PTT server 112 determines that another multicast call may be used and sends the multicast call related information to the BS 104 along with information about the target PTT members 502, 504. BS 104 begins sending PTT communications by sending notifications to target PTT members 502, 504 over the control channel and then allocating slots from the PTT multicast channel allocated for this second multicast call. The wireless devices 502, 504 will then monitor the PTT multicast channel for PTT communications.

  FIG. 5 illustrates a block diagram 600 of the BS 104. The BS 104 receives information related to audio and data calls from the PTT server 112 through the network interface 604, and transmits the received information as a radio signal to the wireless communication device through the wireless interface 606. BS 104 also receives communications from wireless communication devices and transmits the communications to a remote server. Transmission of communication to the wireless communication device is by a radio signal, and the radio signal is transmitted in a plurality of time slots. These time slots are resources that the control device 610 in the BS 104 allocates to each communication.

  Since the wireless communication device typically listens to all slots in the PTT multicast channel (the wireless communication device filters out all packets that do not belong to its call, eg, based on the multicast IP address and port The BS 104 can dynamically allocate slots according to the arrival time of the media packet to ensure minimal delay. Further, the BS 104 may dynamically adjust the bandwidth for this call based on the load on the BS 104.

  The BS 104 has a finite number of resources (time slots) that can be allocated for all communications including PTT calls, normal wireless telephone calls, data communications, and so on. One way to efficiently use these resources is to allocate a predetermined number of slots for handling multicast communications. For example, if N time slots are needed to handle one multicast communication, the controller 610 can allocate 10 × N to handle the multicast communication. When there is no multicast communication, the controller 610 can use these time slots for handling other types of communication. When a multicast communication arrives, then N time slots are assigned to this multicast communication. When the second multicast communication arrives, then a second set of N time slots is assigned to this second multicast communication, and so on. For example, when the eleventh multicast communication arrives and the control device 610 no longer has a pre-allocated time slot, the control device 610 may then reject the eleventh multicast communication. Or, if additional time slots are available, they may be allocated from that general resource pool. This scheme ensures that each multicast communication has a certain quality. An advantage provided by the present invention is that the delay for transmitting the media packet is reduced because the BS 104 can allocate slots based on the arrival time of the media packet.

  Another way to efficiently handle resources is to allocate a predetermined number of slots and then use them for all multicast communications. For example, if 10 × N time slots are allocated to handle multicast communication and there is only one multicast communication, all 10 × N time slots are used for handling this multicast communication. When the second multicast communication arrives, the control device 610 then divides 10 × N time slots into these two multicast communications, each having 5 × N time slots. When the third multicast communication arrives, the control device 610 allocates 3.3 × N slots to each multicast communication. The server continues to divide resources into all multicast communications until the resources allocated to each multicast call reach a predefined minimum, and then reject additional multicast calls. This scheme ensures that all incoming multicast communications are handled, but the less simultaneous multicast communications, the greater the performance.

  Other methods can also be used, such as a combination of the algorithms described above. For example, paying an additional fee allows a PTT group to gain a special status and is assigned a higher priority than other PTT groups. When a PTT communication is received from this high priority PTT group, the control device 610 allocates a predetermined number N of time slots to the PTT communication. If two PTT communications are subsequently received from the normal PTT group, the controller divides the remaining time slots into these two normal PTT groups without affecting the higher priority PTT group, Each receives (total number of slots−N) / 2 time slots. If another PTT communication is received from the higher priority second PTT group while all three PTT communications are still in progress, the controller 610 may send another predefined number of time slots N Are assigned to this second high priority PTT communication. Therefore, each of the two ordinary PTT communications will be allocated (total number of slots−2N) / 2 time slots. Further thereafter, when the third PTT communication arrives from the normal client, each of the high priority PTT communication receives N time slots, and each of the normal PTT communication (total number of slots−2N). The controller 610 will reallocate resources to receive / 3 time slots. This algorithm ensures a consistent quality for high paying clients while still providing services to regular clients.

  FIG. 6 illustrates a flowchart of a process 700 that may be used at BS 104. In block 702, the BS 104 allocates a number of slots for use by multicast communication. These slots may be allocated based on the algorithm presented above. In block 704, the BS 104 checks for any incoming multicast call. If there is no incoming multicast call, then process 700 follows the no branch to block 716 where BS 104 checks whether the multicast communication has just ended. If there is no multicast communication to end, process 700 follows the no branch back to 704, where BS 104 simply continues to monitor incoming multicast communication. However, if the multicast communication is terminated, the process 700 follows the yes branch to block 718 where the BS 104 reassigns the time slot to either a new incoming multicast communication or a general resource pool. assign. Process 700 then returns to block 704 where BS 104 continues to monitor incoming multicast communications.

  Returning to block 704, if there is an incoming multicast call, the process 700 follows the yes branch to block 706 where the BS 104 checks to see if there are any available slots. If there is no slot available for an incoming multicast call, process 700 follows the no branch to block 714 where BS 104 begins an error handling routine. This routine may include returning a message to the server. However, if there are slots available, process 700 follows the yes branch and proceeds to block 708. In block 708, the BS 104 sends a notification to the target wireless device. The target wireless device receives the notification and tunes to the appropriate multicast channel. In block 710, the BS 104 allocates a number of time slots to the multicast channel according to a predefined algorithm. Any one or a combination of the algorithms described above may be used. At block 712, the BS 104 broadcasts the multicast communication on the appropriate multicast channel. Process 700 then proceeds to monitor further incoming multicast communications.

  In operation, when the user, John, wants to use his wireless device equipped with PTT functionality to communicate with his crew, John activates his wireless device. The wireless device sends a floor request to the PTT server 112. The PTT server 112 receives the request, confirms that no other user has the right to speak, and grants the right to speak to John. The authorization message is received by John's wireless device 102, after which John can speak toward his wireless device 102. The wireless device sends John's message to the PTT server 112. The PTT server 112 receives a PTT message from John and identifies members of John's PTT group. The PTT server 112 detects that two target receivers 402, 404 are served by a single BS 104 and then sends a PTT message to the BS 104 with instructions for a multicast call.

  The BS 104 will reserve some bandwidth (time slots) to handle multicast calls and will allocate the required bandwidth to each incoming multicast call. After receiving the PTT message from the PTT server 112, the BS 104 checks whether it has enough bandwidth to handle the new multicast call. After confirming that there are sufficient resources to handle the new multicast call, the BS 104 will notify the target receivers 402, 404 about the PTT message and broadcast the PTT message on the PTT multicast channel. The target wireless device 402, 404 will then tune to the PTT multicast channel and receive the PTT message. After broadcasting the PTT message, the BS 104 will reallocate bandwidth for other incoming multicast calls.

  Although this embodiment has been described above as in a PTT environment, the present invention is not limited to PTT communications. In a broader sense, the system and method optimizes bandwidth utilization by the BS 104 that supports multiple multicast communications. Considering the methods that can be executed on a wireless service provider's computing device, the methods may be performed by a program that resides in a computer readable medium. The program instructs a server or other computing device having a computer platform to perform the method steps. The computer readable medium may be a server memory or may be in a connectivity database. Further, the computer readable medium may be in a secondary storage medium that can be loaded into the wireless communication device computer platform. The secondary storage medium is such as a magnetic disk or tape, optical disk, hard disk, flash memory, or other storage medium known in the art.

  In the situation of FIGS. 3-6, this embodiment may also be implemented by operating a portion of a wireless network, such as a wireless communication device or server, to execute a sequence of machine readable instructions. Good. Although the process is illustrated in sequence, the method may be implemented in a different sequence or as an event driven process. The instructions can reside in various types of signal bearing or data storage primary, secondary or tertiary media. The medium may include, for example, a RAM (not shown) that is accessible by or present in the wireless network component. The instructions may be stored on a variety of machine-readable data storage media, whether contained in RAM, diskettes, or other secondary storage media. This includes DASD storage devices (eg, conventional “hard disks” or RAID arrays), magnetic tape, electronic read-only memory (eg, ROM, EPROM, or EEPROM), flash memory cards, optical storage devices (eg, CDs). -ROM, WORM, DVD, digital optical tape), paper "punch" cards, or other suitable data storage media including digital and analog transmission media.

  While this embodiment has been particularly shown and described with reference to preferred embodiments thereof, various changes in form and detail, as set forth in the following claims, are within the spirit of the invention. It will be understood by those skilled in the art that it can be done without departing from the scope and scope. For example, while the above description is based on audio PTT communication, it is understood that the apparatus, system and method can be easily modified to support other types of media, such as video, data, etc. The Further, although elements of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims (29)

In a method for transmitting a plurality of multicast communications over a wireless communications network,
Allocating a plurality of transmission slots for multicast communication according to a pre-defined algorithm at the base station;
Receiving a plurality of multicast communications from a server at the base station;
Assigning a predetermined number of transmission slots to each multicast communication according to the predefined algorithm;
Transmitting each multicast communication to a plurality of wireless devices via the predetermined number of transmission slots within a multicast channel.   The method of claim 1, wherein the predefined algorithm is a fixed bandwidth scheme.   The method of claim 2, wherein the fixed bandwidth scheme allocates a fixed number of transmission slots to each multicast communication.   The method of claim 1, wherein the predefined algorithm is an adjustable bandwidth scheme.   The method of claim 4, wherein the adjustable bandwidth scheme divides the plurality of transmission slots equally into the plurality of multicast communications.   The method of claim 1, further comprising: sending a notification to a recipient of each multicast communication over a control channel.   The method of claim 1, wherein each multicast communication is a push-to-talk communication.   The method of claim 1, further comprising transmitting information about the predetermined number of transmission slots to the plurality of wireless devices before a multicast communication is transmitted to the plurality of wireless devices. In a system for transmitting multiple multicast communications over a single multicast channel over a wireless communications network,
A network interface unit that receives multicast communication from the server;
A radio interface unit capable of establishing multicast communication for each of a plurality of wireless communication devices;
A controller unit capable of allocating a predetermined number of transmission slots to each multicast communication according to a predefined algorithm;
A system in which each multicast communication is broadcast through multiple transmission slots.   The system of claim 9, wherein the predefined algorithm is a fixed bandwidth scheme.   The system of claim 10, wherein the fixed bandwidth scheme allocates a fixed number of transmission slots to each multicast communication.   The system of claim 9, wherein the predefined algorithm is an adjustable bandwidth scheme.   The system of claim 12, wherein the adjustable bandwidth scheme divides the plurality of transmission slots equally into the plurality of multicast communications.   The system of claim 9, wherein the wireless interface is further capable of sending notifications to a plurality of wireless communication devices for each multicast communication over a control channel.   The system of claim 9, wherein each multicast communication is a push-to-talk communication. In an apparatus for transmitting multiple multicast communications over a single multicast channel over a wireless communications network,
Means for receiving multicast communication from the server;
Means for establishing multicast communication for a plurality of wireless communication devices;
Means for allocating a predetermined number of transmission slots to each multicast communication according to a predetermined algorithm,
A device in which each multicast communication is broadcast through multiple transmission slots.   The apparatus of claim 16, wherein the predefined algorithm is a fixed bandwidth scheme.   18. The apparatus of claim 17, wherein the fixed bandwidth scheme allocates a fixed number of transmission slots to each multicast communication.   The apparatus of claim 16, wherein the predefined algorithm is an adjustable bandwidth scheme.   20. The apparatus of claim 19, wherein the adjustable bandwidth scheme divides the plurality of transmission slots equally into the plurality of multicast communications.   The apparatus of claim 16, wherein the means for establishing a multicast channel is further capable of sending notifications to a plurality of wireless communication devices for each multicast communication via a control channel.   The apparatus of claim 16, wherein the plurality of multicast communications are part of a push-to-talk communication. In a computer readable medium comprising at least one instruction that, when executed by a machine, causes the machine to perform an operation, the instruction comprises:
A set of instructions for allocating a plurality of transmission slots for multicast communication according to a predefined algorithm at the base station;
A set of instructions for receiving a plurality of multicast communications from a server at the base station;
A set of instructions for allocating a predetermined number of transmission slots to each multicast communication according to the predefined algorithm;
A set of instructions for transmitting each multicast communication to a plurality of wireless devices via the predetermined number of transmission slots within a multicast channel.   The computer readable medium of claim 23, wherein the predefined algorithm is a fixed bandwidth scheme.   The computer-readable medium of claim 24, wherein the fixed bandwidth scheme allocates a fixed number of transmission slots to each multicast communication.   The computer-readable medium of claim 23, wherein the predefined algorithm is an adjustable bandwidth scheme.   27. The computer readable medium of claim 26, wherein the adjustable bandwidth scheme equally divides the plurality of transmission slots into the plurality of multicast communications.   24. The computer-readable medium of claim 23, further comprising a set of instructions for sending notifications to a plurality of wireless communication devices for each multicast communication over a control channel.   The computer-readable medium of claim 23, wherein each multicast communication is a push-to-talk communication.

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