TWI449371B - Method of selecting operating frequency for user equipment in a wireless communications system and related apparatus - Google Patents

Description

Method for selecting operating frequency of wireless communication system and related device

The present invention relates to a method for selecting an operating frequency of a wireless communication system and related apparatus, and more particularly to a method for selecting an operating frequency of a multimedia broadcast and a multicast service among users of a wireless communication system and related devices.

The third-generation mobile communication system adopts the wireless access method of Wideband Code Division Multiple Access (WCDMA), which can provide high spectrum utilization efficiency, far-reaching coverage and high quality and high speed. Multimedia data transmission can meet various QoS service requirements at the same time, provide flexible and diversified two-way transmission services, and provide better communication quality, effectively reducing communication interruption rate. In order to enhance multimedia features third-generation mobile communication systems, third-generation mobile communications Alliance ^{(the 3 rd Generation Partnership Project,} 3GPP) specification developed by the communications, providing multimedia broadcast and multicast service (Multimedia Broadcast Multicast Service, MBMS ). The Multimedia Broadcasting Multicast Service is a point-to-multipoint data transmission service built on the network architecture of the original Universal Mobile Telecommunications System (UMTS) with Internet Protocol (IP). The packet is a medium, so that a single data source can simultaneously transmit the same service to multiple clients.

According to the communication protocol specifications established by the 3rd Generation Mobile Communications Alliance, the multimedia broadcast and multicast services provide broadcast and multicast delivery modes (MBMS Broadcast/Multicast Delivery Mode). When the UE wants to use the multimedia broadcast and multicast service, it needs to first subscribe to a Broadcast Multicast Service Center (BM-SC) to establish a service agreement between the two. Different service modes provide different Service Provision Phases, where the service delivery phase of the broadcast delivery mode includes Service announcements, Session Starts, multimedia broadcasts, and MBMS notifications. , Data Transfer and Session Stop; and the service protocol phase of the multicast transmission mode includes subscription, service announcement, joining, session start, multimedia broadcast. And MBMS notification, Data Transfer, Session Stop and Leaving; in order to provide customized services, the multicast transmission mode has increased participation and departure for both users. In the design phase, when the user enters the participation phase, the system can perform authentication and accounting records on the client. The above service agreement phase should be known to the industry and will not be described here.

On the other hand, as is known to those of ordinary skill in the art, from the perspective of radio resource control, all "logically" data transfer channels, whether for use by the client for data transfer, or for wireless The control signal transmission exchange used by the resource control layer is defined by the concept of "Radio Bearer" (RB). The meaning of the so-called radio bearer includes a one-way or one pair of uplink and downlink logical data transfer switching channels on the user side; and a one-way or one-pair uplink and downlink logical data transfer switching channel on the network side. For example, the wireless access network (UTRAN) can transmit multimedia broadcast and multicast service control signaling to the UE by transmitting a radio bearer; the UE can stop receiving the multimedia broadcast and the multicast service by releasing the radio bearer. In addition, in the radio resource control specification, the radio resource control state can be divided into a non-connected and connected mode, the unconnected mode includes an idle (Idle) mode, and the connected mode includes a cell paging (CELL_PCH), and a wireless registration area paging. (URA_PCH), a cell forward access (CELL_FACH) and a cell exclusive (CELL_DCH) state.

Multimedia broadcast and multicast services include broadcast and multicast service types (Broadcast/Multicast Service Type). Generally speaking, there is no charge for the broadcast service. Therefore, when the user receives the broadcast service, the joining service protocol is not required, and the wireless access network adopts the broadcast transmission mode to transmit the service information through the point-to-multipoint radio bearer. On the other hand, for the multicast service, the wireless access network depends on the charging situation and decides to use the broadcast and multicast transmission mode. In the multicast transmission mode, the UE performs the participation service protocol to perform the charging function; in the broadcast transmission mode, the UE does not need to participate in the service agreement. Then, the wireless access network grasps the number of clients that can receive the multimedia broadcast and the multicast service through a Counting Procedure to decide to use the point-to-point or point-to-multipoint radio bearer to deliver the service information. In the following, the transmission by the wireless access network using the point-to-point radio bearer may be referred to as a Point-to-Point Transfer Mode; the transmission using the point-to-multipoint radio bearer is called a one-to-many Point-to-Multipoint Transfer Mode.

In general, a wireless access network includes two or more carrier frequencies, which are used to provide different types of services, and achieve good resource utilization by appropriately allocating the number of clients per carrier frequency. Thus, based on simplified system control and resource savings, the wireless access network concentrates all multimedia broadcast and multicast services on one carrier frequency. When the user wants to receive the multimedia broadcast and the multicast service, the wireless access network will transmit a multimedia broadcast and multicast service correction information (MBMS MODIFIED SERVICES INFORMATION) message to the user, and the message includes a multimedia broadcast and group. The MBMS Preferred frequency information component is used to notify the UE to convert the operating frequency to a Preferred Frequency Layer to receive the multimedia broadcast and the multicast service. Then, after the frequency conversion, the UE stores the previous operating frequency.

For the UE in the idle mode, the cell paging, the wireless registration area paging or the cell forward access state, in the point-to-multipoint transmission mode, when a multimedia broadcast and multicast service proceeds to the stop service protocol phase, the wireless The receiving network transmits a multimedia broadcast and multicast service correction service information message, which includes a multimedia broadcast and multicast service required MBMS required UE action component. By setting the client-side behavior component of the multimedia broadcast and multicast service requirements as "Release PTM RB", the wireless access network informs the user to stop the service protocol phase, and the user terminal releases the relevant point-to-multipoint radio bearer. To stop receiving multimedia broadcasts and multicast services. In addition, if the multimedia broadcast and multicast service correction service information message includes a multimedia broadcast and multicast service distribution indicator (MBM Sdispersion indicator) component, the user terminal will return to the previously stored content after stopping receiving the service. Operating frequency. Therefore, the wireless access network actively stops the multimedia broadcast and the multicast service, and the user terminal can be transferred out of the specified frequency to avoid network congestion caused by the excessive number of users in the specified frequency.

In addition, the wireless access network periodically transmits a multimedia broadcast and multicast service (MBMS GENERAL INFORMATION) message to the client to notify the user of the current usage of the specified frequency. If the message includes a MBMS PL Service Restriction Information component, it means that the wireless access network will not provide any non-multimedia broadcast and multicast services within the specified frequency (non -MBMS Service), that is, the specified frequency is currently in the congestion state; conversely, if the component does not exist in the message, it means that the specified frequency still has redundant resources, so in addition to the multimedia broadcast and multicast service In addition, the wireless access network will also provide non-multimedia broadcast and multicast services, such as voice call services, within the specified frequency.

In order to enhance the application of Mobile TV, the 3rd Generation Mobile Communications Alliance introduces a multimedia broadcast and multicast service selected service (MBMS Selected Services) in the RRC layer, which is a multimedia broadcast and multicast service. The sub-service set of the broadcast service included in the service (MBMS_ACTIVATED_SERVICES) variable is used to inform the wireless access network which broadcast services have been selected by the client. The service has been selected through the multimedia broadcast and the group broadcast service, and the wireless access network can inform the user of the specific broadcast service information, such as the service program start time or the program length, etc., according to the needs of the user terminal. In addition, the multimedia broadcast and multicast services defined by the 3rd Generation Mobile Communications Alliance have selected services, especially mobile TV services, which should remain readily receivable. This means that there will be no wireless access network to notify the client to stop the service protocol phase, but the user decides to stop receiving the service. Furthermore, according to the radio resource control specification established by the 3rd Generation Mobile Communication Alliance, in the point-to-multipoint transmission mode, for the idle mode, cell paging, wireless registration area paging or cell forward access state, when When the user stops receiving the multimedia broadcast and the multicast service by itself, it only needs to release the relevant point-to-multipoint radio bearer, and does not consider any action of shifting the operating frequency. In this way, even if the UE no longer receives any multimedia broadcast and multicast services, it will continue to stay within the specified frequency for providing multimedia broadcast and multicast services.

It can be seen from the above that the multimedia broadcast and group broadcast service has selected the service only by the user terminal to terminate the reception, and after stopping receiving the service, the user terminal will stay at the original designated frequency. In addition, with the newly added client receiving the service, the specified frequency may cause network congestion due to the excessive number of users. In addition, if the specified frequency is blocked, the wireless access network will not be able to provide new non-multimedia broadcast and multicast services, such as Mobile Terminated Call. For users who no longer receive multimedia broadcast and multicast services, continuing to operate at the specified frequency will miss the opportunity to receive non-multimedia broadcast and multicast services.

Accordingly, the present invention provides a method for selecting an operating frequency in a subscriber end of a wireless communication system and associated apparatus to avoid congestion at the frequency used to provide multimedia broadcast and multicast services.

The present invention discloses a method for selecting an operating frequency in a user terminal of a wireless communication system. The method includes: when starting to receive a multimedia broadcast and multicast service of a multimedia service group, switching the operating frequency from a first frequency to a second frequency; and determining to no longer receive the multimedia service group In any multimedia broadcast and multicast service, the operating frequency is switched from the second frequency to the first frequency.

The present invention discloses a communication device for a wireless communication system for correctly selecting an operating frequency to avoid congestion at a frequency used to provide multimedia broadcast and multicast services. The communication device includes a control circuit, a central processing unit and a storage device. The control circuit is used to implement the functions of the communication device. The central processor is disposed in the control circuit for executing a code to manipulate the control circuit. The storage device is disposed in the control circuit and coupled to the central processor for storing the code. The code includes: when the multimedia broadcast and the multicast service of one of the multimedia service groups is started to be received, the operating frequency is switched from a first frequency to a second frequency; and the multimedia is determined not to be received. When any of the multimedia broadcast and multicast services of the service group is serviced, the operating frequency is switched from the second frequency to the first frequency.

The present invention further discloses a method for selecting an operating frequency in a user terminal of a wireless communication system. The method includes: when starting to receive a multimedia broadcast and multicast service of a multimedia service group, switching the operating frequency from a first frequency to a second frequency; and determining to no longer receive the multimedia service group When any of the multimedia broadcast and multicast services and the service status associated with the second frequency is determined to be congestion, the operating frequency is switched from the second frequency to the first frequency.

The present invention further discloses a communication device for a wireless communication system for correctly selecting an operating frequency to avoid frequency generation congestion for providing multimedia broadcast and multicast services, and avoiding missed reception of non-multimedia broadcast and multicast services. chance. The communication device includes a control circuit, a central processing unit and a storage device. The control circuit is used to implement the functions of the communication device. The central processor is disposed in the control circuit for executing a code to manipulate the control circuit. The storage device is disposed in the control circuit and coupled to the central processor for storing the code. The code includes: when the multimedia broadcast and the multicast service of one of the multimedia service groups is started to be received, the operating frequency is switched from a first frequency to a second frequency; and the multimedia is determined not to be received. When any of the multimedia broadcast and multicast services of the service group and the service status associated with the second frequency is determined to be congestion, the operating frequency is switched from the second frequency to the first frequency.

Please refer to FIG. 1 , which is a functional block diagram of a wireless communication device 100 . For simplicity, FIG. 1 depicts only one input device 102, an output device 104, a control circuit 106, a central processing unit 108, a storage device 110, a code 112, and a transceiver 114 of the wireless communication device 100. . In the wireless communication device, the control circuit 106 executes the code 112 stored in the storage device 110 through the central processing unit 108, thereby controlling the operation of the wireless communication device 100, and receiving the signal input by the user through the input device 102 (such as a keyboard). Or output signals such as pictures and sounds through the output device 104 (such as a screen, a speaker, etc.). The transceiver 114 is configured to receive or transmit a wireless signal, transmit the received signal to the control circuit 106, or output the signal generated by the control circuit 106 in a radio manner. In other words, in terms of the architecture of the communication protocol, the transceiver 114 can be considered part of the first layer, and the control circuit 106 is used to implement the functions of the second and third layers. Preferably, the wireless communication device 100 is applied to a third generation mobile communication system.

Please continue to refer to FIG. 2, which is a schematic diagram of the code 112 in FIG. The code 112 includes an application layer 200, a third layer 202, and a second layer 206 connected to a first layer 198. A radio resource control unit 222 is located at the third layer 202 for controlling the first layer 198 and the second layer 206, and performing peer-to-peer communication with a wireless access network. In addition, the RRC control unit 222 can change the radio resource control state of the wireless communication device 100, which is switched to idle (Idle), cell paging (CELL_PCH), and wireless registration area paging (URA_PCH) according to network system requirements or communication environment changes. , between the cell forward access (CELL_FACH) or cell-specific (CELL_DCH) state.

For multimedia broadcast and multicast services, the wireless access network can form a RRC message and an Information Element (IE) through a point-to-multipoint radio bearer (P-Point-to-Multipoint Radio Bearer, p -t-m RB), transmitting information about the service or control signaling to the wireless communication device 100. In the idle state, cell paging, wireless registration area paging or cell forward access state, when the application layer 200 terminates a multimedia broadcast and multicast service, the radio resource control unit 222 will actively release the relevant radio bearer to point-to-multipoint. The radio bears to stop the receiving action of the multimedia broadcast and the multicast service. In this case, the embodiment of the present invention provides an operating frequency selection code 220 in the code 112 to improve the selection mechanism of the operating frequency after the user actively stops the multimedia broadcast and the multicast service to avoid the service frequency. Congestion. Please refer to FIG. 3, which is a flow chart of the process 30 according to an embodiment of the present invention. The process 30 is used to select an operating frequency among one of the wireless communication systems, which can be compiled into the operating frequency selection code 220, and includes the following steps: Step 300: Start.

Step 302: When the multimedia broadcast and the multicast service of one of the multimedia service groups are started, the operating frequency is switched from a first frequency to a second frequency.

Step 304: When it is determined that the multimedia broadcast and the multicast service of the multimedia service group are no longer received, the operation frequency is switched from the second frequency to the first frequency.

Step 306: End.

According to the process 30, the embodiment of the present invention provides a multimedia service group to the UE through the second frequency. The multimedia service group includes at least one multimedia broadcast and multicast service, and each multimedia broadcast and multicast service is selected as a broadcast type (Broadcast Type) or a multicast type (Multicast Type), or a multimedia broadcast and group broadcast service has been selected. Service (MBMS Selected Services). In this case, the UE can receive one or more multimedia broadcast and multicast services at a time from the multimedia service group. The client operates at the first frequency before initiating the reception of the multimedia broadcast and the multicast service. When the UE initiates receiving the multimedia broadcast and the multicast service, the operating frequency is first switched from a first frequency to a second frequency, and the first frequency is stored. When the UE actively stops receiving any of the selected multimedia broadcast and multicast services, the related point-to-multipoint radio bearers will be released. In addition, when the UE determines to no longer receive any of the multimedia broadcast and multicast services of the multimedia service group, the operating frequency is switched from the second frequency to the first frequency. When the UE hops out of the second frequency, it indicates that the UE no longer occupies the radio resource of the second frequency to reserve radio resources to other UEs. Therefore, the embodiment of the present invention can prevent the UE that no longer receives any multimedia broadcast and multicast service from staying at the second frequency, causing the number of users to continuously increase, thereby preventing the congestion of the second frequency.

Please refer to FIG. 4, which is a flowchart of a process 40 according to an embodiment of the present invention. The process 40 is for selecting an operating frequency among one of the wireless communication systems, which can be compiled into the operating frequency selection code 220, and includes the following steps: Step 400: Start.

Step 402: When starting to receive one of the multimedia broadcast and multicast services of a multimedia service group, the operating frequency is switched from a first frequency to a second frequency.

Step 404: When it is determined that the multimedia broadcast and the multicast service of the multimedia service group are no longer received, and the service status of one of the second frequencies is determined to be congestion, the operation frequency is switched from the second frequency to The first frequency.

Step 406: End.

According to the process 40, the embodiment of the present invention provides a multimedia service group to the UE through the second frequency. The multimedia service group includes at least one multimedia broadcast and multicast service, and each multimedia broadcast and multicast service is selected as a broadcast type (Broadcast Type) or a multicast type (Multicast Type), or a multimedia broadcast and group broadcast service has been selected. Service (MBMS Selected Services). In this case, the UE can receive one or more multimedia broadcast and multicast services at a time from the multimedia service group. During operation of the second frequency, the UE can know the current usage of the second frequency by periodically receiving a multimedia broadcast and MBMS GENERAL INFORMATION message. If the multimedia broadcast and multicast service general information message includes a MBMS PL Service Restriction Information component, the service status of the second frequency is determined to be congestion, and the second frequency is The new non-multimedia broadcast and multicast service is not provided; on the contrary, if the message does not include the component, it means that the second frequency still has redundant resources, and the user can perform new non-multimedia through the second frequency. Broadcast and multicast services, such as Mobile Terminated Call.

Therefore, according to the process 40, the user terminal operates at the first frequency before starting to receive the multimedia broadcast and the multicast service. When the UE initiates receiving the multimedia broadcast and the multicast service, the operating frequency is first switched from a first frequency to a second frequency, and the first frequency is stored. When the UE actively stops receiving any of the selected multimedia broadcast and multicast services, the related point-to-multipoint radio bearers will be released. In addition, when it is decided that no multimedia broadcast and multicast service is stopped and the service status of the second frequency is determined to be congestion, the UE switches the operating frequency from the second frequency to the first frequency. In this way, for the user that decides to no longer receive any multimedia broadcast and multicast service, if the service status of the second frequency is determined to be congestion at this time, the embodiment of the present invention requires the user terminal to remove the second frequency. In this way, not only can the second frequency be further blocked, but the UE can also avoid the missed reception of non-multimedia broadcast and multicast services.

In summary, in the prior art, when the user terminal of the non-dedicated radio resource control state actively stops the multimedia broadcast and the multicast service (such as the multimedia broadcast and the multicast service have selected services), the user terminal only releases the relevant information. Point-to-multipoint radio bearers and continue to operate on this service frequency. Embodiments of the present invention provide two options with respect to conventional techniques. The first is to remove the service frequency when the UE decides not to receive any multimedia broadcast and multicast services. The other is to remove the service frequency when the UE decides not to receive any multimedia broadcast and multicast service and the service frequency status is judged to be congestion. Therefore, the embodiment of the present invention can avoid the congestion of the service frequency due to the excessive number of users, and also avoid the opportunity for the user to miss receiving the non-multimedia broadcast and the multicast service.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100. . . Mobile communication device

102. . . Input device

104. . . Output device

106. . . Control circuit

108. . . CPU

110. . . Storage device

112. . . Code

114. . . transceiver

200. . . Application layer

202. . . the third floor

206. . . Second floor

198. . . level one

220. . . Operating frequency selection code

222. . . Radio resource control unit

30, 40. . . Process

300, 302, 304, 306, 400, 402, 404, 406. . . step

Figure 1 is a functional block diagram of a wireless communication device.

Figure 2 is a schematic diagram of the code in Figure 1.

Figure 3 is a flow chart showing the flow of an embodiment of the present invention.

Figure 4 is a flow chart showing the flow of an embodiment of the present invention.

30. . . Process

300, 302, 304, 306. . . step

Claims (20)

A method for selecting an operating frequency in a user terminal of a wireless communication system, comprising: switching the operating frequency from a first frequency when starting to receive a multimedia broadcast and a multicast service of a multimedia service group a second frequency; before receiving the multimedia broadcast and multicast service, terminating the receiving of the multimedia broadcast and multicast service; and if it is determined that the multimedia broadcast and multicast service of the multimedia service group is no longer received, The operating frequency is switched by the second frequency to the first frequency. The method of claim 1, further comprising: releasing a plurality of point-to-multipoint radio bearers (ptm RBs) when the multimedia broadcast and the multicast service are stopped, the plurality of points The multipoint radio bearer corresponds to the multimedia broadcast and multicast service. The method of claim 1, wherein the multimedia broadcast and multicast service is a Broadcast Type. The method of claim 1, wherein the multimedia broadcast and multicast service is a multimedia broadcast and multicast service selected service (MBMS Selected Services). The method of claim 1, wherein the multimedia broadcast and multicast service is Multicast Type. The method of claim 1, wherein the client operates in an idle mode. The method of claim 1, wherein the client operates in a cell paging (CELL_PCH) state. The method of claim 1, wherein the client operates in a wireless registration area paging (URA_PCH) state. The method of claim 1, wherein the client operates in a cell forward access (CELL_FACH) state. The method of claim 1, wherein the wireless communication system is a third generation mobile communication system. A communication device for a wireless communication system for correctly selecting an operating frequency to avoid a congestion condition for providing a frequency of a multimedia broadcast and a multicast service, the communication device comprising: a control circuit for implementing The function of the communication device; a central processing unit is disposed in the control circuit for executing a code to control the control circuit; and a storage device is disposed in the control circuit and coupled to the central processing unit, Used Storing the code; wherein the code includes: when starting to receive a multimedia broadcast and multicast service of a multimedia service group, switching the operating frequency from a first frequency to a second frequency; Terminating the receiving of the multimedia broadcast and multicast service before the end of the broadcast and multicast service; and switching to the second frequency if the multimedia broadcast and the multicast service of the multimedia service group are no longer received For the first frequency. The communication device of claim 11, wherein the code is further included to release a plurality of point-to-multipoint radio bearers (ptm RBs) when the multimedia broadcast and the multicast service are stopped. The plurality of point-to-multipoint radio bearers correspond to the multimedia broadcast and multicast service. The communication device of claim 11, wherein the multimedia broadcast and multicast service is a broadcast type. The communication device of claim 11, wherein the multimedia broadcast and multicast service is a multimedia broadcast and multicast service selected service (MBMS Selected Services). The communication device of claim 11, wherein the multimedia broadcast and multicast service The multimedia broadcast and group broadcast service is a group broadcast service (Multicast Type). The communication device of claim 11, which operates in an Idle mode. The communication device of claim 11, which operates in a cell paging (CELL_PCH) state. The communication device of claim 11, which operates in a wireless registration area paging (URA_PCH) state. The communication device of claim 11, which operates in a cell forward access (CELL_FACH) state. The communication device of claim 11, wherein the wireless communication system is a third generation mobile communication system.