KR101056833B1 - Scheduling Method for Multimedia Broadcast Multicast Service - Google Patents

Abstract

The present invention provides a scheduling method for a multimedia broadcast multicast service for improving performance and reducing radio resource efficiency of a mobile terminal while simultaneously receiving broadcast and multicast services including a unicast service in one mobile terminal. It is about. In the scheduling method for a multimedia broadcast multicast service according to the present invention, a scheduling request message is received from a plurality of downlink buffers, and when a scheduling request message is received, a plurality of radio network temporary according to a preset scheduling allocation priority. Determining an allocation priority of an Radio Network Temporary Identifier (RNTI) and at least one radio network temporary identifier among the plurality of radio temporary identifiers is determined. Checking whether it can be allocated, and if the allocation is possible, allocating in consideration of the service type of the temporary temporary network identifier.

Broadcast RNTI, Multicast RNTI, Unicast RNTI, Scheduling

Description

Scheduling method for multimedia broadcast multicast service {Scheduling method for mutimedia broadcast multicast service}

The present invention relates to broadcast multicast services in packet-based mobile communication systems, and more particularly, to scheduling for broadcast multicast services.

This study is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and ICT. [National Management No.: 2008-S-006-01, Title: Development of Open IPTV (IPTV 2.0) Technology in Wired and Wireless Environment]

From the point of view of convergence convergence, service technologies for delivering multimedia contents in the form of broadcasts or multicasts through mobile communication networks have been introduced and are already in the realization stage. For example, 3GPP LTE (3rd Generation Partnership Project Long Time Evolution) mobile communication system improves the disadvantages of low transmission speed and high cost of data service provided by existing communication system, thereby providing high speed data service at low cost regardless of time and place. It is an advanced next generation communication system that can be provided. The 3GPP LTE mobile communication system provides not only voice service but also packet service and multimedia broadcast multicast service (hereinafter referred to as MBMS service) to the mobile terminal.

The MBMS service is a service for transmitting one multimedia data to a plurality of users through one wireless channel through a wireless network, thereby saving radio resources. The MBMS service may support a real time streaming service, a still image service, a file download service, and a carousel service.

MBMS transmission methods generally include single cell transmission and multiple cell transmission.

In a single cell transmission method, a multicast service is provided only to a specific cell category, and mobile terminals in a specific cell category are provided with a multicast service according to a result of being scheduled in an eNodeB (hereinafter, referred to as a base station).

In the multi-cell transmission method, multicast data is synchronized and transmitted to all cells in a corresponding service area, and mobile terminals included in all cells are multicast according to a scheduled result in a multi-cell / multicast coordination entity (MCE). Receive service. This multi-cell transmission method is mainly used for broadcasting services such as, for example, TV services, but due to the limitations on the frequency and the application of adaptive modulation and coding (AMC), the number of services is limited. There is a limit. On the other hand, a broadcast service such as a personal broadcast including a mobile IPTV and providing a plurality of contents is preferably used by a single cell transmission method rather than a multi-cell transmission method because various users use it.

Meanwhile, a mobile terminal provided with various services through a single cell transmission method receives various services through one assigned user identifier (Radio Network Temporary Identifier: RNTI). The RNTI used in the 3GPP LTE radio section is a unique identifier used in each cell and is assigned to the user terminal one by one. Currently, the user identifier in the radio section defined in 36.321 Media Access Control (MAC) specification is Semi-Persistent Scheduling C-RNTI, Temporary C used for Cell-RNTI (C-RNTI) and Voice over Internet Protocol (VoIP). -RNTI, Random Access (RA-RNTI), P-RNTI (Paging), and SI-RNTI (System Information) are defined. In addition, the radio segment user identifier for the MBMS service mentions that it is possible to allocate an RNTI for each service in TS36.300.

On the other hand, if the mobile terminal includes a unicast service and can simultaneously receive broadcast and multicast services, there are multiple RNTIs that the mobile terminal should receive at the same time interval (hereinafter referred to as TTI). Can be. In general, the mobile terminal should detect the RTNI that the mobile terminal should receive in the subframe received in every TTI. That is, the mobile terminal determines the number of RNTIs that can be detected in one TTI according to the blind detection level. Accordingly, when the mobile terminal receives a plurality of services, the mobile terminal detects the RNTI by lowering or raising the blind detection level. However, if the blind detection level is lowered for RNTI detection, the performance of the mobile terminal may be degraded. On the contrary, if the blind detection level is increased, the number of RNTIs that can be detected in one TTI is reduced.

An object of the present invention is to solve such a problem, and to provide a mobile terminal with simultaneous unicast, broadcast, and multicast services.

Furthermore, an object of the present invention is to ensure that performance and efficiency are not degraded when a mobile terminal simultaneously receives unicast, broadcast and multicast services.

Furthermore, the present invention aims to distinguish RNTI in order for the mobile terminal to simultaneously receive unicast, broadcast and multicast services.

The foregoing technical problem is achieved by the characteristic aspects of the present invention described below. In the scheduling method for a multimedia broadcast multicast service according to the present invention, a scheduling request message is received from a plurality of downlink buffers, and when a scheduling request message is received, a plurality of radio network temporary according to a preset scheduling allocation priority. Determining an allocation priority of an Radio Network Temporary Identifier (RNTI) and at least one radio network temporary identifier among the plurality of radio temporary identifiers is determined. Checking whether it can be allocated, and if the allocation is possible, allocating in consideration of the service type of the temporary temporary network identifier.

A service type that includes a broadcast service, a multicast service, and a unicast service according to an additional aspect of the present invention may include a wireless network temporary including a broadcast wireless network temporary identifier, a multicast wireless network temporary identifier, and a unicast wireless network temporary identifier. The broadcast service or the multicast service is divided into identifiers, and grouped into one wireless network temporary identifier for similar content, and the grouped broadcast service or multicast service is distinguished by a logical channel identifier.

Unicast radio network temporary identifier according to an additional aspect of the invention is characterized in that it comprises a C-wireless network temporary identifier or SPS-wireless network temporary identifier that is not associated with a broadcast or multicast service.

According to this aspect of the present invention, the unicast, broadcast and multicast radio network temporary identifiers are distinguished, and the allocation priority of the radio network temporary identifiers classified by service type is determined to check whether they can be transmitted to the mobile terminal. Can be transferred afterwards.

When the allocating step according to an additional aspect of the present invention allocates radio resources to traffic having a broadcast radio network temporary identifier, acquiring a number N _UE of radio network temporary identifiers currently assigned to the plurality of mobile terminals; comparing the obtained N minus the _UE and one from the maximum number of radio network temporary identifier in a plurality of time intervals while the mobile terminal can be allocated N _mAX -1, comparison result more N _UE is N _mAX -1 If greater, stops the allocation of radio resources to the traffic of the broadcast radio temporary identifier, but if N _UE is less than N _MAX -1, allocating radio resources to the traffic of the broadcast radio temporary identifier, and assigning radio resources the broadcast root CAD radio network temporary identifier when transmitted to a plurality of mobile terminals, _UE N and broadcast the radio network temporary identification number of the plurality of mobile terminals Characterized in that it comprises a step for increasing the N _BROAD.

According to this aspect of the present invention, it is possible to determine whether to allocate radio resources to traffic having a broadcast radio network temporary identifier and to assign the broadcast radio network temporary identifier to mobile terminals.

When the allocating step according to an additional aspect of the present invention allocates radio resources to traffic having a multicast radio network temporary identifier, acquiring an N _UE of a mobile terminal that receives multicast data among a plurality of mobile terminals; comparison, the acquired N _UE and one of the time comparing N _mAX -1 the mobile terminal is obtained by subtracting 1 from the maximum number of radio network temporary identifiers that can be allocated for the acquisition interval, the _UE result N N _mAX -1 If it is greater than the radio resource allocation to stop the traffic of the multicast radio network temporary identifier, if N _UE is less than N _MAX -1, the step of allocating a radio resource to the traffic of the multicast radio network temporary identifier, and the radio resource allocation The received multicast radio network temporary identifier is transmitted to the mobile terminal receiving the multicast data, the mobile terminal receiving the multicast radio network temporary identifier Increasing the number of _UEs .

According to this aspect of the present invention, it is possible to determine whether radio resources can be allocated to traffic having a multicast radio network temporary identifier, thereby assigning the multicast radio network temporary identifier to mobile terminals using the multicast service. .

When the allocating step according to an additional aspect of the present invention allocates radio resources to traffic having a unicast radio network temporary identifier, acquiring N _UEs of the plurality of mobile terminals, and broadcasting allocated to the plurality of mobile terminals. Acquiring N _BROAD of the wireless network temporary identifier, summing with the N _UE to obtain N _SUM, and obtaining a maximum wireless network temporary identifier that can be allocated by a plurality of mobile terminals in one time interval with the obtained N _SUM . Comparing N _MAX -1 minus one and counting, if the N _SUM is greater than N _MAX -1, suspend allocation of radio resources to the traffic of the unicast radio temporary identifier, but N _SUM is greater than N _MAX -1. If small, allocating a radio resource to the traffic of the unicast radio network temporary identifier, and assigning a radio resource to the plurality of mobile terminals. After the transmission, it characterized in that it comprises a step for increasing the N of _UE unicast mobile terminal with a wireless network, receiving a temporary identifier.

According to this aspect of the present invention, it is possible to determine whether radio resources can be allocated to traffic having a unicast radio network temporary identifier, thereby assigning unicast radio network temporary identifiers to mobile terminals.

As described above, in the scheduling method for the multimedia broadcast multicast service according to the present invention, one mobile terminal can simultaneously receive unicast, broadcast and multicast services, and at the same time, the performance and power of the mobile terminal There is an effect that can increase the efficiency of radio resources such as waste.

In addition, the base station for allocating the radio network temporary identifier for each service type to a plurality of mobile terminals may use the radio network temporary identifier for each service type to a plurality of mobile terminals using an allocation algorithm regardless of a preset radio network temporary identifier priority. By assigning, it is possible to increase the scalability and utilization of the algorithm.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through these embodiments.

1 illustrates a system configuration for providing an Evolved MBMS (EMBMS) service based on a 3GPP mobile communication network (WCDMA network). This configuration is modeled after the structure defined in Release 8 of 2008, but the present invention can be applied to the system of the previous version and also to the system to be proposed in the future.
Referring to FIG. 1, first, a 3GPP mobile communication network manages radio resources for wireless transmission with a user equipment (UE) 100 and a plurality of mobile terminals (UE) 100 that receive broadcast multimedia content packets. And an evolved Universal Mobile Telecommunications Network Terrestrial Radio Access Network (E-UTRAN) including a plurality of eNodeBs (hereinafter referred to as base stations) 101 which are in charge of establishing a radio channel, and control packet services by interworking with the E-UTRAN. Evolved Packet Multicast Service Center (Evolved Packet Core), which is composed of an Evolved Packet Core (EPC) that is responsible for transmitting and receiving traffic to the outside, is a control system for providing EMBMS services (hereinafter referred to as eBM-SC) (107) It includes. These network components manage the services that can be provided for each service area and perform a session and bearer setup and management for delivering contents received from an external content provider server 108, thereby providing terminals 100 at a specified time. ) To deliver multimedia content.

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The base station 101 constituting the EUTRAN receives uplink signals transmitted from the plurality of mobile terminals 100 at the physical layer level, and transmits downlink signals to the corresponding mobile terminal 100. That is, the base station 101 transmits and receives signals with the mobile terminal 100 and serves as an access point of the mobile terminal 100. For reference, the mobile terminal 100 communicates with a mobile terminal 100 existing in a corresponding cell through a radio channel by managing radio resources in a cell unit.

The EPC supports the mobility management entity (MME) 102, the Serving Gateway (SGW) 103, the PDN Gateway (PGW) 104, and the EMBMS service, which manage service control and traffic paths for general packet data services. It is composed of network elements such as MBMS1 105 and MBMS2 106 that manages service control and traffic paths, and performs interworking with EUTRAN for session management and mobility management radio bearer setup for each service. The Mobility Management Entity (MME) 102, the Serving Gateway (SGW) 103, and the PDN Gateway (PGW) 104 provide a unicast bearer function for performing packet data services through a mobile communication network, and MBMS1 (105). MBMS2 106 provides a multicast bearer function for the EMBMS service.

Meanwhile, the eBM-SC 107 is a node in charge of controlling the EMBMS service and must exist as a functional element of the LTE system in order to provide the EMBMS service. The eBM-SC 107 is a subject of management and control of the EMBMS service, and provides a function of preparing a service of the EMBMS mobile terminal 100 and delivering service information. In addition, the eBM-SC 107 provides a function of managing the EMBMS service user and service information, authorizing the EMBMS bearer service in the mobile communication network, initiating a service, and transmitting and transmitting the EMBMS information. Provides a service announcement service that delivers the types of services that can be received in, the nature of the content to be received from the service and parameters necessary for communication. The eBM-SC 107 is connected with the MBMS2 106 to provide an EMBMS service to the mobile terminal 100.

The interface between the eBM-SC 107 and the MBMS2 106 uses an IP interface used when the MBMS2 106 is connected to an external Internet network. The eBM-SC 107 serves as an entry point to the content providing server 108 to deliver EMBMS information, and may itself serve as a content provider (CP).

The mobile terminal 100 uses the EMBMS service information (hereinafter referred to as EMBMS data) received from the eBM-SC 107 to provide the user with a list and detailed information of a service that can be received in a corresponding region. Allows you to choose the EMBMS service you want. That is, according to the user's EMBMS service request, the mobile terminal 100 registers a request to receive the corresponding EMBMS service in the eBM-SC 107, and thus starts a specific EMBMS service from the eBM-SC 107. The multicast service related content requested in time is received and received.

The eBM-SC 107 transmits the EMBMS data from the content providing server 108 through the MBMS2 106, the MBMS1 105, and the base station 101 through the common channel used in the corresponding service area according to the EMBMS service control. A plurality of mobile terminals 100 in the service area are transmitted. That is, the EMBMS data provided from the content providing server 108 is broadcast multicast data and is controlled through a distributed tree composed of links of sub-nodes of MBMS2 or less under the control of the eBM-SC 107 according to a broadcast schedule for each service. Is transmitted to the mobile terminal (100).

Hereinafter, a scheduling method for providing an EMBMS service to the mobile terminal 100 by the scheduler of the base station will be described in detail with reference to FIGS. 2 to 5.

2 is a flowchart illustrating a scheduling method for providing an EMBMS service to a mobile terminal 100 according to an embodiment of the present invention.

As shown, when the traffic for each bearer is received by the base station 101, a scheduling request message is received from the plurality of downlink buffers at every scheduling time for transmission of the scheduler radio section (S100). When a scheduling request message is received from a plurality of downlink buffers, the scheduler determines and arranges allocation priorities of a plurality of Radio Network Temporary Identifiers (RNTIs) according to a preset scheduling allocation priority. (S110). Thereafter, the scheduler selects the RNTI having the highest priority among the RNTIs arranged according to the allocation priority (S120). As the RNTI to be allocated is selected, the scheduler checks whether the radio resource can be allocated to the traffic of the selected RNTI (S130), and terminates the scheduling currently performed when there is no radio resource to allocate.

On the other hand, if the radio resource can be allocated to the traffic of the selected RNTI as a result of the check, the scheduler performs a radio resource allocation procedure in consideration of the service type of the RNTI.

That is, the scheduler allocates radio resources to the traffic of the RNTI for which the service type is selected (S140). The excitation service type includes a broadcast service, a multicast service, and a unicast service, and these service types are divided into RNTIs. In addition, the broadcast service or the multicast service may be defined by grouping one wireless network temporary identifier for each similar content, and the grouped broadcast service or the multicast service may be divided into logical channel identifiers.

In general, the broadcast service is a service that can be received at any time without a special request of the mobile terminal 100, the multicast service is a service that can be received after the subscription request of the mobile terminal 100 is completed. Such broadcast service and multicast service group similar subjects or contents and use them as one RNTI. Accordingly, the mobile terminal 100 can easily and quickly obtain an RNTI of a required service type through RNTIs classified for each service type in a TTI, thereby minimizing power waste.

As such, a method of allocating RNTI for each service type will be described in detail with reference to FIGS. 3 to 5.

3 is a flowchart illustrating a method of allocating radio resources to traffic with a broadcast RNTI according to an embodiment of the present invention.

As shown, when the scheduler allocates radio resources to traffic with broadcast RNTI, the scheduler checks whether radio resources can be allocated to traffic with broadcast RNTI (S150). First, the scheduler obtains the number N _UEs of RNTIs currently owned by a plurality of mobile terminals 100. That is, the scheduler acquires N _UEs of all the mobile terminals 100 connected to the base station because the mobile service 100 can use the broadcast service without registering the eBM-SC 107. In addition, the scheduler may provide a broadcast service to all mobile terminals 100 regardless of an active or idle state. In particular, since the idle terminal C-RNTI, which is a terminal identifier of a wireless section, is not defined, an idle state mobile terminal (International Mobile Station Identity: IMSI) is used. Acquire N _UE of 100).

Thereafter, the scheduler checks whether the acquired N _UE is smaller than a value obtained by subtracting 1 from N _MAX , which is the maximum number of RNTIs that can be received in one TTI (S151). If the N _UE is greater than N _MAX -1 as a result of the check, the scheduler stops radio resource allocation to the broadcast RNTI and re-performs step S120 (S152). On the other hand, if the check result N _UE is less than N _MAX -1, the scheduler allocates a radio resource for the broadcast RNTI (S153). Then, the scheduler increases the N _UE obtained from the plurality of mobile terminals (100) (S154). Then, the scheduler increases N _BROAD, which is the number of broadcast RNTIs allocated to the plurality of mobile terminals 100, and performs step S120 again (S155). Accordingly, the scheduler may allocate radio resources to the traffic of broadcast RNTI transmitted to the plurality of mobile terminals 100 or terminate the allocation.

On the other hand, as mentioned above, since the broadcast service defines similar content as one broadcast RNTI, it is possible to minimize resource waste of the broadcast RNTI.

4 is a flowchart illustrating a method of allocating radio resources to traffic having a multicast RNTI according to an embodiment of the present invention.

As shown, when the scheduler allocates a radio resource to traffic having a multicast RNTI, the scheduler checks whether the radio resource can be allocated to traffic of the multicast RNTI (S160).

The multicast RNTI is allocated radio resources through the following procedure. First, the scheduler obtains the number N _UEs of RNTIs currently held from the mobile terminals 100 using the current multicast service among the plurality of mobile terminals 100. That is, since only the mobile terminal 100 registered in the eBM-SC 107 uses the multicast service, the scheduler currently holds from the mobile terminals 100 using the current multicast service among the plurality of mobile terminals 100. Acquire the number N _UE of the RNTIs. On the other hand, when the idle mobile terminal 100 uses a multicast service, the scheduler obtains the N _UE of the idle mobile terminal 100 using IMSI, which is one common identifier.

Thereafter, the scheduler checks whether the obtained N _UE is smaller than a value obtained by subtracting 1 from N _MAX , the maximum number of RNTIs that can be received in one TTI (S161). If the N _UE is greater than N _MAX -1 as a result of the check, the scheduler stops radio resource allocation to the traffic of the multicast RNTI and re-performs step S120 (S162).

On the other hand, if the check result N _UE is less than N _MAX -1, the scheduler allocates a radio resource to the traffic of the multicast RNTI to the mobile terminal 100 using the multicast service (S163). Thereafter, the scheduler increments the N _UE obtained from the mobile terminals 100 using the multicast service, and performs step S120 again (S164). Accordingly, the scheduler may allocate radio resources to the traffic of the multicast RNTI transmitted to the mobile terminals 100 using the multicast service or terminate the allocation.

On the other hand, as mentioned above, the multicast service can minimize the resource waste of the multicast RNTI as similar content is defined and used as one multicast RNTI.

5 is a flowchart illustrating a method of allocating radio resources to traffic having a unicast RNTI according to an embodiment of the present invention.

As shown, when the scheduler allocates radio resources to traffic with a unicast RNTI such as C-RNTI or SPS-RNTI that is not related to broadcast service or multicast service, the scheduler is assigned to traffic with unicast RNTI. It is checked whether the resource can be allocated (S170).

First, the scheduler obtains the number N _UEs of RNTIs currently held by a plurality of mobile terminals 100. In this case, the scheduler may provide unicast service to all mobile terminals 100 regardless of activation or idle state. In particular, the idle mobile terminal 100 acquires the N _UE of the idle mobile terminal 100 using IMSI, which is one common identifier because C-RNTI is not defined. When the N _UE of the plurality of mobile terminals (100) acquiring, scheduler N _{(NU + BROUAD)} summing the N _UE obtained from the generated up to the current broadcast RNTI number of N _BROAD and a plurality of mobile terminals (100) value Acquire. Subsequently, the scheduler checks whether the captured N _{(NU + BROUAD)} is smaller than a value obtained by subtracting 1 from N _MAX , the maximum number of RNTIs that can be received in one TTI (S171). If the check result N _{(NU + BROUAD)} is greater than N _MAX -1, the scheduler stops assigning radio resources to traffic having a unicast RNTI and performs step S120 again (S172). On the other hand, if N _{(NU + BROUAD)} is less than N _MAX -1 as a result of the check, the scheduler allocates a radio resource to traffic having a unicast RNTI (S173). Thereafter, the scheduler increases the N _UEs acquired from the plurality of mobile terminals 100 and then re-performs step S120 (S174). Accordingly, the scheduler can allocate radio resources to the traffic with unicast RNTI transmitted to the plurality of mobile terminals 100 or terminate the allocation.

So far I looked at the center of the preferred embodiment for the present invention.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a system configuration diagram for providing an Evolved MBMS (EMBMS) service based on a 3GPP mobile communication network (WCDMA network);

2 is a flowchart illustrating a scheduling method for providing an EMBMS service to a mobile terminal 100 according to an embodiment of the present invention;

3 is a flowchart illustrating a method for allocating radio resources to traffic with a broadcast RNTI according to an embodiment of the present invention;

4 is a flowchart illustrating a method for allocating radio resources to traffic having a multicast RNTI according to an embodiment of the present invention;

5 is a flow diagram illustrating a method for allocating radio resources to traffic with unicast RNTI in accordance with an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: UE 101: base station (eNods)

102: MME 103: SGW

104: PGW 105: MBMS1

106: MBMS2 107: Broadcast Service Center (eBM-SC)

108: Content provision server (CP server / MB source server)

Claims (4)

A scheduler of a base station performs multimedia broadcast multicast service scheduling to provide EMBMS service to a plurality of mobile terminals. Receiving, by the scheduler, a scheduling request message from a plurality of downlink buffers; When the scheduling request message is received, determining, by the scheduler, allocation priorities of a plurality of Radio Network Temporary Identifiers (RNTIs) according to a preset scheduling allocation priority; When an allocation priority of at least one radio network temporary identifier among the plurality of radio network temporary identifiers is determined, the scheduler checks whether the radio resource can be allocated to traffic of the determined radio network temporary identifier. Assigning considering a service type of the temporary temporary network identifier; Method of performing a multimedia broadcast multicast service scheduling comprising a. The method of claim 1, The service type including a broadcast service, a multicast service, and a unicast service is divided into the wireless network temporary identifier including a broadcast wireless network temporary identifier, a multicast wireless network temporary identifier, and a unicast wireless network temporary identifier, The broadcast service or the multicast service is defined by grouping the one wireless network temporary identifier for each similar content, and the grouped broadcast service or the multicast service is divided into logical channel identifiers. How to perform multimedia broadcast multicast service scheduling. The method of claim 2, The unicast radio temporary identifier is And a C-Wireless Temporary Identifier or an SPS-Wireless Temporary Identifier not associated with the Broadcast Service or the Multicast Service. The method of claim 2, The plurality of mobile terminals may receive a temporary ID for each type of service regardless of an activation or idle state, and when the operation state is in the idle state, the plurality of mobile terminals receive a common mobile station identification number (IMSI), which is a common identifier. And receiving the radio network temporary identifier for each service type by using the multimedia broadcast multicast service scheduling.

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