Method for the scheduled transmission of MBMS data in UMTSTechnical Field
The present invention relates to a multimedia broadcast/multicast service of UMTS (universal mobile telecommunications system), and more particularly, to a scheduled transmission method of MBMS data.
Background
The Universal Mobile Telecommunications System (UMTS) is based on the well-known Global System for Mobile communications (GSM) standard
An extended third generation mobile communication system. The standard is a european standard and its purpose is to provide an improved mobile communication service based on the GSM core network and wideband code division multiple access (W-CDMA) technology.
Fig. 1 shows a network structure of a universal UMTS.
As shown in fig. 1, the UMTS can be simply divided into a terminal, a UTRAN and a core network.
The UTRAN includes one or more Radio Network Subsystems (RNSs). Each RNS includes one RNC and one or more node bs managed by the RNC.
The node B is managed by the RNC, and it may receive information transmitted by a physical layer of a terminal (e.g., a mobile station, a user equipment, and/or a user cell) through an uplink and may transmit data to the terminal through a downlink. The node B may then operate as an access point for the UTRAN for the terminal.
The RNC performs functions including allocation and management of radio resources and can operate as an access point with respect to the core network.
The main function of UTRAN is to compose and maintain a Radio Access Bearer (RAB) suitable for a call connection between the terminal and the core network. The core network applies end-to-end quality of service (QoS) requirements to the RAB, and thus, the UTRAN can satisfy the end-to-end QoS requirements by constructing and maintaining the RAB.
The RAB service can be divided into an Iu bearer service and a radio bearer service on a lower concept. The Iu bearer service handles reliable user data transmission between the border node of the UTRAN and the core network, while the radio bearer service handles reliable user data transmission between the terminal and the UTRAN.
In UMTS, traffic can be classified into four QoS types, e.g., a regular type, a streaming type, an interactive type, and a background type, according to the characteristics of QoS. The conventional type is a type of symmetric service traffic requiring a minimum fixed delay, which does not allow buffering and provides a guaranteed bit rate. The streaming type is a type of asymmetric traffic requiring minimum variable delay, which allows buffering and can provide a guaranteed bit rate. The interactive type is a type of asymmetric traffic requiring a moderate variable delay, which allows buffering and does not provide a guaranteed bit rate. The background type is a type of asymmetric traffic requiring large variable delay, which allows buffering and cannot provide guaranteed bit rate.
Fig. 2 illustrates a radio protocol between a terminal and a UTRAN based on the 3GPP radio access network standard.
Referring to fig. 2, a radio protocol is vertically formed by a physical layer, a data link layer, and a network layer, and is horizontally divided into a user plane adapted to transmit data information and a control plane adapted to transmit control signals.
The user plane is an area where user traffic information is transmitted, for example, voice or an IP packet is transmitted. The control plane is an area to which control information is sent, for example, interfaces of a network or maintenance and management information of a call.
In fig. 2, the protocol layers may be divided into a first layer (L1), a second layer (L2) and a third layer (L3), which are based on three lower layers of an Open System Interconnection (OSI) standard model that is well known in the communication system.
The first layer (PHY) provides an information transfer service to an upper layer by using various radio transmission techniques.
The first layer is connected to the MAC layer through a transmission channel, and data can be transferred between the MAC layer and the PHY layer through the transmission channel.
The MAC layer provides a re-allocation service of MAC parameters in order to allocate and re-allocate radio resources.
The MAC layer may be connected with a radio link control (RTC) layer through one logical channel and may provide various logical channels according to the type of transmitted information. In general, when information of the control plane is transmitted, a control channel may be used. When transmitting information of the user plane, a traffic channel may be used.
The MAC may be divided into a MAC-b sublayer, a MAC-d sublayer, and a MAC-c/sh sublayer according to the type of transmission channel managed. The MAC-b sublayer manages one BCH (broadcast channel) among system information to handle broadcasting, and the MAC-c/sh sublayer manages common transmission channels such as FACH (forward access channel), DSCH (downlink shared channel), or others, which are shared by other terminals.
In UTRAN, the MAC-c/sh sublayer is located at the controlling rnc (crnc) and manages channels shared by each terminal in a cell, and thus, there is one MAC-c/sh sublayer in each cell.
The MAC-d sublayer manages one DCH (dedicated channel), one special terminal-specific transmission channel. Thus, the MAC-d sublayer may be located at a service rnc (srnc) managing the corresponding terminal, and one MAC-d sublayer may also exist at each terminal.
The Radio Link Control (RLC) layer supports a reliable data transmission and can perform segmentation and connection functions of RLC service data cells (SDUs) from an upper layer. The RLC SDU transmitted by the upper layer may be adjusted in size according to throughput capability at the RLC layer and by attaching header information thereto, and then transmitted to the MAC layer in one PDU (protocol data cell). The RLC layer includes an RLC buffer adapted to store RLC SDUs or RLC PDUs from an upper layer.
A broadcast/multicast control (BMC) layer performs the function of subscribing to a cell broadcast message (CBS) sent by the core network and broadcasting the CBS to UE locations in a specified cell. At the UTRAN side, the CBS message sent by the upper layers may be combined with information, which may include: ID, sequence number, or coding scheme of the message, and a logical channel is transmitted to the RLC layer and the MAC layer through a CTCH (general traffic channel), a logical channel in a BMC message. In this case, the logical channel CTCH may map one FACH (forward access channel), one transmission channel, and one S-CCPCH (second common control physical channel), one physical channel.
A Packet Data Convergence Protocol (PDCP) layer, which is an upper layer of the RLC layer, allows data to be efficiently transmitted over a relatively small bandwidth radio interface using a network protocol such as IPv4 or IPv 6. For this purpose, the PDCP layer performs a function of reducing unnecessary control information, which may be referred to as header compression, and in this regard, header compression techniques, RFC2507 and RFC3095 (robust header compression: ROHC), defined by the Internet standardization group in the IETF (Internet engineering task force) may be used. In these methods, since only the information necessary portion in the data header portion is transmitted and the control information is transmitted, the amount of data transmission can be reduced.
The RRC layer is located at the lowest part of the third layer (L3), which is defined only by the control plane and controls logical channels, transmission channels, and physical channels related to the setting, resetting, and release of RBs. The RB denotes a service provided by a second layer adapted for data transmission between the terminal and the UTRAN, and setting the RB refers to a process of stipulating the characteristics of a protocol layer and a channel, which are necessary for providing a particular service, and setting various detailed parameters and operation methods.
The Cell Broadcast Service (CBS) related to the BMC layer will now be discussed.
A message service including giving and generating characters or numerical values at a terminal or between a terminal and a network may be referred to as a Short Message Service (SMS). SMS can be divided into two categories, cell broadcast SMS (SMS-CBS) and point-to-point SMS (SMS-PP), which are adapted to send the same message to one or more cells.
CBS service, which can broadcast a variety of CBS messages, corresponding to SMS-CBS, to each user in a certain designated area.
CBS messages are broadcast to a geographic area, which may be referred to as a broadcast area. This area may include one or more cells or be integrally formed as a Public Land Mobile Network (PLMN). Individual CBS messages may be broadcast to a geographic area according to a mutual contract between the information provider and the PLMN operator.
The BMC message used in the BMC protocol includes a CBS message adapted to transmit user information, a predetermined message adapted to allow a terminal to conveniently receive the CBSC message, and a CBS41 message adapted to transmit a Short Message Service (SMS) message transmitted by an ANSI 41 network. Each message sent by the UTRAN can only be sent to the terminal. The terminal performs a Discontinuous Reception (DRX) function by using information of a predetermined message transmitted by the UTRAN, thereby reducing power consumption of the battery.
The subscription of the BMC message may be divided into a first level subscription and a second level subscription. The first level of predetermination may be determined (allocated) to be suitable for transmitting frames of Common Traffic Channel (CTCH) data.
Fig. 3 illustrates a first level of the predetermined method. The numbers in the first row represent the number (SFN) values of the system frame.
The logical channel CTCH may be mapped to a physical channel (S-CCPCH) through a transmit channel (FACH). The first level of reservation may specify frames of a physical channel by data of a logical channel (CTCH) in advance. The data transmitted to the CTCH may be transmitted in some frame of consecutive M numbers, and the frame group may be repeated by some frame of a period (N).
For example, as shown in fig. 3, data transmitted by the CTCH is always transmitted at two consecutive frame intervals and repeated at a period of six frames. When the SFN value is "K" and repeats with a period (N), a frame group of CTCH data may start to be transmitted. In fig. 3, a frame group starts when the SFN value is 2 and the transmission is repeated for the next 6 cycles.
The subscription of the first level is made in the same way on each CBS service. That is, the same frame may be used to allocate the same cell for each service of the CBS. The first level of subscription is performed at the RRC layer, includes values N, K and M in system information and broadcasts to the terminals.
The second level of reservation may divide the frame allocated in the first level of reservation into one CBS reservation period. The second level reservation is made at the BMC layer, and the terminal may obtain CBS reservation period information by receiving a BMC reservation message. The BMC reservation message includes length information of the CBS reservation period and start point information of the CBS reservation period.
The CBS reservation length indicates a length between a start point and an end point of a CBS reservation period that starts after the BMC reservation message. The starting point of the CBS reservation period indicates a difference between a transmission time point of the current BMC reservation message and a starting point of the CBS reservation period starting after the BMC reservation message.
Thus, when the terminal receiving the CBS message receives the BMC reservation message, it can recognize the start and end times of the next CBS reservation period. The terminal can obtain the next CBS reservation period information by receiving the BMC reservation message in the CBS reservation period. With this method, the terminal can recognize a time when the BMC message is not transmitted, and can perform Discontinuous Reception (DRX).
Fig. 4 shows the structure of the BMC subscribe message.
As shown in fig. 4, the BMC reservation message provides information of one or more BMC messages transmitted in the next CBS reservation period. The new message bit table parameter indicates whether each message sent in the next predetermined period of CBS is a new message or a pre-broadcast message. The specification parameter of the message indicates the type or ID of each BMC message transmitted in the next CBS reservation period. At this time, the message refers to one of a CBS message, a predetermined message, and a CBS41 message.
The maximum size of a CBS message may be generally limited to 1230 octets, and thus the CBS message is not suitable for broadcasting or multicasting multimedia data. Furthermore, because CBS messages can be broadcast to each terminal existing in each designated cell, multicasting suitable for providing services to a designated group of terminals cannot be efficiently wirelessly transmitted.
Therefore, in order to wirelessly broadcast or multicast multimedia data to a designated terminal group, a new service called a multimedia broadcast/multicast service (MBMS) has been proposed.
MBMS will now be discussed.
MBMS is a multimedia data service suitable for transmitting data such as audio, video or image data through a unidirectional point-to-multipoint bearer service. MBMS can be divided into a broadcast mode and a multicast mode. That is, the MBMS may be divided into an MBMS broadcast service and an MBMS multicast service.
The MBMS broadcast mode is a service suitable for transmitting multimedia data to each user in a broadcast area. The broadcast area refers to an area where a broadcast service is available. One or more broadcast areas may exist in one PLMN, one or more broadcast services may exist in one broadcast area, and one broadcast service may be provided to a plurality of broadcast areas.
The MBMS multicast mode is a service suitable for transmitting multimedia data only to a designated user group existing in one multicast area. The multicast area refers to an effective area for a multicast service. One or more multicast areas may exist in one PLMN, one or more multicast services may exist in one multicast area, and one multicast service may be provided to a plurality of multicast areas.
In multicast mode, users are required to receive a specified multicast service in association with a multicast group. At this time, the multicast group means a user group receiving the specified multicast service, and the union means an action of getting approval of the multicast group attempting to receive the specified multicast service.
MBMS data transmission has two types of logical channels: MBMS Control Channel (MCCH) and MBMS Traffic Channel (MTCH). The MCCH channel is used to transmit MBMS control information to the MBMS terminal. The MTCH channel is used to transmit data of a specified MBMS service to the MBMS terminal. Therefore, if a plurality of MBMS services are all active in one cell, a plurality of MTCHs should be configured in the cell. In the case of the multicast mode, only MTCH can be configured in the MBMS terminal that has associated the designated MBMS service.
The MAC layer attaches a MAC header file to the received MBMS data and transfers it to the physical layer of the base station through a common transmission channel. Subsequently, the MBMS data is encoded and modulated in the physical layer and transmitted to the terminal through a common physical channel. At this time, the common transmission channel transmits the data in a certain time cell of a Transmission Time Interval (TTI), and the common physical channel mapped to the common transmission channel can be transmitted in a frame cell.
In order to be able to receive multiple services transmitted by multiple channels simultaneously, the simplest method is to receive several channels simultaneously, which, however, would make the terminal quite complex.
Thus, in order to solve this problem, in the conventional CBS service, a predetermined method is employed in which the time during which a specific service is provided is predetermined and notified. This method is useful in case of simultaneously receiving MBMS and a different service or MBMS and control information. In addition, the terminal may perform a Discontinuous Reception (DRX) operation to avoid battery consumption when not receiving the MBMS.
However, in the case of the conventional CBS service, only one service can be provided in one cell, so the same predetermined parameters are set in the cell. Meanwhile, in case of MBMS, different services can be provided in one cell, so a predetermined method different from the predetermined CBS is required.
Reference is made to the above for an appreciation that additional or alternative details, capabilities, and/or technical background may be incorporated in the above references.
Disclosure of Invention
It is therefore an object of the present invention to provide a scheduled method of transmission that is suitable for radio access networks broadcasting and multicasting high speed data with different characteristics.
Another object of the present invention is to provide a multimedia service providing method in which data transmission times applicable to an MBMS service can be set to be different, so that different services or different channels can be received when one designated MBMS service data is not transmitted.
In order to achieve at least the above objects in whole or in parts, there is provided a multimedia service data scheduling method of a wireless communication system having a multimedia broadcast/multicast service (MBMS) service provided to a terminal group consisting of a plurality of terminals, the method comprising: designating a radio resource of a radio channel adapted to transmit the designated MBMS data; and transmitting the designated radio resource information to the terminal group applicable to each MBMS.
The multimedia service data reservation method additionally includes each terminal of the terminal group receiving the multimedia service data based on the transmitted radio resource information.
Preferably, the radio channel is a common physical channel.
Preferably, the radio resource is a predetermined information characterizing a time when the MBMS data is to be transmitted.
Preferably, different radio resources are allocated to different MBMS data.
Preferably, the radio resources are designated when the UTRAN sets or resets a Radio Bearer (RB) for a designated MBMS.
Preferably, radio resources may be allocated periodically or aperiodically when setting up an RB for the designated MBMS.
Preferably, the terminal can receive the MBMS data during the time period indicated by the frame allocation information.
Preferably, the terminal may receive a control signal during a time period other than that indicated by the frame allocation information.
Preferably, the terminal may stop receiving each traffic data during a time period other than that indicated by the frame allocation information.
Preferably, the terminal may receive service data other than the MBMS service during a time period not indicated by the predetermined information.
Preferably, the radio resources are specified by a Radio Resource Control (RRC) layer or by a multimedia layer.
Preferably, when radio resources are designated by a Radio Resource Control (RRC) layer, the radio resources are transmitted in a frame manner.
Preferably, the radio resource may be transmitted to the terminal group through a broadcast channel or a control channel.
Preferably, if the radio resource is specified by the multimedia layer, the radio resource may be attached to the MBMS scheduling message to be transmitted.
Preferably, different MBMS scheduling messages may be transmitted to the terminal group through different channels.
Preferably, the channel may be a common traffic channel.
Preferably, the MBMS scheduling message includes a sequence number or an identification number of the designated MBMS data to be broadcast or multicast next and scheduling information.
Preferably, the MBMS scheduling message may be transmitted periodically multiple times while the designated MBMS is provided.
Preferably, the MBMS scheduling message indicates whether the corresponding MBMS data is transmitted for the first time or has been repeatedly transmitted.
Preferably, the MBMS scheduling message may be transmitted non-periodically a plurality of times while the designated MBMS is provided.
Preferably, the MBMS scheduling message indicates a length of an MBMS scheduling period and a length between a start point and an end point of the MBMS scheduling period.
In order to achieve at least the above advantages in whole or in parts, there is also provided a multimedia service providing method of a wireless communication system for providing a multimedia service to a terminal group consisting of a plurality of terminals, the method comprising: distributing frames to the appointed multimedia service; sending the distribution information of the frame to a designated terminal group; and each terminal group receives the multimedia service data based on the frame allocation information.
Preferably, the multimedia service is a multimedia broadcast/multicast service (MBMS).
Preferably, the frame is a frame in a common physical channel through which the designated multimedia service data can be transmitted.
Preferably, different multimedia service data can be allocated to different frames.
Preferably, the frame is allocated when one Radio Bearer (RB) is set or reset for one designated MBMS.
Preferably, the frame is allocated periodically or non-periodically when one RB has been set for one designated MBMS.
Preferably, the frame may be allocated by a Radio Resource Control (RRC) layer.
Preferably, the frame indicates a time when the specific MBMS data is transmitted.
Preferably, the frame allocation information indicates a time interval of one designated MBMS data to be transmitted and a period of the repetition time interval.
Preferably, the terminal group receives the MBMS data during a time period indicated by the frame allocation information.
Preferably, the terminal group may receive a control signal during a time period other than that indicated by the frame allocation information.
Preferably, the terminal group may stop receiving each traffic data for a certain period of time other than that indicated by the frame allocation information.
Preferably, the frame allocation information may be transmitted through one broadcast channel and one control channel.
In order to achieve at least the above advantages in whole or in parts, there is also provided a multimedia service providing method of a wireless communication system for providing a multimedia service to a terminal group consisting of a plurality of terminals, the method comprising: separately executing data transmission scheduled by each multimedia service; transmitting predetermined information to a designated terminal group; and receiving the multimedia service data by each terminal in the terminal group according to the predetermined information.
Preferably, the multimedia service is a multimedia broadcast/multicast service (MBMS).
Preferably, the reservation is performed when the UTRAN sets or resets a Radio Bearer (RB) suitable for a designated multimedia service.
Preferably, the data transmission reservation may be separately performed, and reservation information suitable for each multimedia service may be transmitted.
Preferably, the predetermined information may be transmitted a plurality of times periodically or aperiodically while a Radio Bearer (RB) suitable for a designated multimedia service is set.
Preferably, the predetermined information may be transmitted through different common traffic channels.
Preferably, the predetermined information is time information when the specified data is to be transmitted.
Preferably, the subscription information is transmitted in addition to the MBMS subscription message.
Preferably, different MBMS services may use different MBMS scheduling messages.
Preferably, different MBMS scheduling messages may be transmitted to the terminal group through different channels.
Preferably, the MBMS scheduling message includes a sequence number or an identification number of the designated MBMS data to be broadcast or multicast next and scheduling information.
Preferably, the MBMS scheduling message includes information indicating whether the corresponding MBMS data is transmitted for the first time or has been repeatedly transmitted.
Preferably, the MBMS scheduling message may be transmitted a plurality of times periodically while the designated MBMS is provided.
Preferably, the MBMS scheduling message may be transmitted non-periodically a plurality of times while the designated MBMS is provided.
Preferably, the MBMS scheduling message indicates a length of an MBMS scheduling period and a length between a start point and an end point of the MBMS scheduling period.
Preferably, the predetermined information is generated by a broadcast and multicast control layer of the UTRAN.
Preferably, the broadcast and multicast control layer transmits the predetermined information to the lower layer.
Preferably, the predetermined information is transmitted to a broadcast and multicast control layer designating a terminal group.
Preferably, the broadcast and multicast control layer of the terminal transmits the received predetermined information to a lower layer.
Preferably, the terminal group receives the multimedia service data during a time period indicated by the predetermined information.
Preferably, the terminal group receives the control signal during a time period other than that indicated by the predetermined information.
Preferably, the terminal group receives service data other than the MBMS in a time period other than that indicated by the predetermined information.
Preferably, the terminal group receives data for which reception of the service is stopped during a time period other than that indicated by the predetermined information.
According to the present invention, there is provided a method of transmitting data of at least one point-to-multipoint service from a network to at least one mobile terminal in a wireless communication system, the at least one mobile terminal joining each of the at least one point-to-multipoint service, the method comprising: determining scheduling information for each of the at least one point-to-multipoint service, wherein the scheduling information specifies start information at which data for each of the at least one point-to-multipoint service is continuously transmitted and duration information indicating the number of frames of a continuous frame group in which the data for the point-to-multipoint service is transmitted; and transmitting data of each point-to-multipoint service according to the determined scheduling information.
According to another aspect of the present invention, there is provided a method of discontinuously receiving data of a joined point-to-multipoint service from a network in a wireless communication system, the method comprising: receiving scheduling information for the point-to-multipoint service, wherein the scheduling information specifies start information at which data of each of the at least one point-to-multipoint service is continuously transmitted and duration information indicating the number of frames of a continuous frame group in which the data of the point-to-multipoint service is transmitted; and receives data of the point-to-multipoint service according to the received scheduling information.
According to still another aspect of the present invention, there is provided a method of scheduling a point-to-multipoint service in a mobile communication system having a network and at least one user terminal joining at least one point-to-multipoint service, the method comprising: periodically transmitting, by the network, a point-to-multipoint scheduling information message via the common channel to inform when to schedule transmission of the point-to-multipoint service via the common channel, thereby transmitting the point-to-multipoint scheduling information message according to a logical channel configuration applicable to a corresponding physical channel; and determining, by the user terminal, whether to discontinuously receive the data of the physical channel based on the point-to-multipoint scheduling information message.
According to an aspect of the present invention, there is provided an apparatus for transmitting at least one point-to-multipoint service data from a network to at least one mobile terminal joined to each of at least one point-to-multipoint service in a wireless communication system, the apparatus comprising: a protocol entity adapted to specify a transmission interval in a control plane by: determining, at a protocol entity, scheduling information for each of the at least one point-to-multipoint service, wherein the scheduling information specifies start information at which data for each of the at least one point-to-multipoint service is continuously transmitted and duration information indicating the number of frames of a continuous frame group in which the data for the point-to-multipoint service is transmitted; and transmitting data of each point-to-multipoint service according to the determined scheduling information.
According to another aspect of the present invention, there is provided an apparatus for discontinuously receiving data of a joined point-to-multipoint service from a network in a wireless communication system, the apparatus comprising: a protocol entity adapted to specify a transmission interval in a control plane by: receiving scheduling information for the point-to-multipoint service at a protocol entity, wherein the scheduling information specifies start information at which data of each of the at least one point-to-multipoint service is continuously transmitted and duration information indicating the number of frames of a continuous frame group in which the data of the point-to-multipoint service is transmitted; and receives data of the point-to-multipoint service according to the received scheduling information.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention will be realized and particularly pointed out in the appended claims.
Drawings
The present invention will be discussed in further detail with reference to the attached drawing figures, wherein like reference numerals refer to like elements, and wherein:
fig. 1 shows a network structure of a universal UMTS system;
fig. 2 shows the structure of a radio access interface protocol between a terminal and a UTRAN according to the 3GPP radio access network standard;
FIG. 3 illustrates a first level of the predetermined method;
FIG. 4 shows the architecture of MBC reservation messages;
fig. 5 shows an MBMS service transmission scheme according to the present invention;
fig. 6 shows an example of an MBMS scheduling message;
fig. 7 shows a time information setting method suitable for transmitting MBMS data through a control layer;
fig. 8 shows a process of receiving MBMS data at one terminal of a terminal group receiving designated MBMS data, which may receive a control signal;
fig. 9 shows a time information setting method suitable for transmitting MBMS data through a user layer; and the combination of (a) and (b),
fig. 10 shows a process of receiving MBMS data at one terminal of a terminal group receiving designated MBMS data, which can receive different services.
Detailed Description
The invention may be implemented in a mobile communication system such as UMTS (universal mobile telecommunications system) developed by 3 GPP. Without being limited thereto, the present invention is also applicable to various communication systems operating with different standards.
The present invention proposes a method in which a wireless communication system can provide multimedia services to a designated terminal group through a common wireless channel, specifies radio resources of the common wireless channel suitable for transmitting data of the designated multimedia services, and transmits various designated multimedia services to a terminal group.
In the present invention, different MBMS services in a cell may have different predetermined parameters. The reservation may indicate whether corresponding MBMS service data (referred to herein as "MBMS data") has been transmitted, and the reservation parameter includes time information indicating a time of the transmitted corresponding data. Therefore, different MBMS services can transmit data at different times without overlapping. That is, only one MBMS service can be provided in one time period.
In the invention, a wireless network appoints a certain time, at which MBMS service data is sent to each MBMS service, and corresponding time information is sent to a terminal group which requires to receive the appointed MBMS service.
Therefore, the terminals belonging to the terminal group can receive other channels of other services while not transmitting the data of the designated MBMS service. If there is no other MBMS service or other channel while no MBMS data is transmitted, the terminals belonging to the corresponding terminal group may transition into an idle state to avoid battery consumption.
In the present invention, if the QoS type of the MBMS service is classified into the background type, the UTRAN can transmit a plurality of MBMS services through a designated physical channel or a designated transport channel. Accordingly, the UTRAN should be able to determine whether to schedule transmission of the MBMS service through the physical/transport channels based on the QoS type of the MBMS service prior to the MBMS service set in the cell. If the QoS types of the MBMS services are all background types, the UTRAN transmits different MBMS services at different transmission intervals.
The MBMS data transmission and reception method of the present invention can be divided into a method of designating a transmission interval on a control plane and a method of designating a transmission interval on a user plane. These two methods can be applied separately or in combination, similar to the layer 1 and layer 2 subscriptions of CBS. In case that the two methods are applied in combination, the method of the transmission interval designated by the control plane corresponds to layer 1 subscription of the CBS, and the method of the transmission interval designated by the user plane corresponds to layer 2 subscription of the CBS.
In the case where the control plane specifies a transmission interval, a third layer protocol such as RRC controls transmission/reception of MBMS data or allocation of a transmission interval. Meanwhile, in case that the user plane specifies a transmission interval, a second layer protocol such as PDCP, RLC and MAC controls transmission/reception of MBMS data or allocation of the transmission interval.
Generally, the MBMS service can be classified into a streaming type service and a background type service. The invention provides a method, which comprises the steps of providing a plurality of background types of MBMS services in a cell, and providing a plurality of background types of MBMS services by a specified downlink MBMS channel at different times respectively.
That is, in the present invention, the UTRAN can distinguish between a streaming type MBMS service and a background type MBMS service, centralize the background type MBMS, time-multiplex the services on one designated MBMS channel, and transmit the services downward. In this case, a plurality of time-multiplexed services cannot overlap each other at the same time. The designated download MBMS channel refers to a transport channel or a physical channel.
For a plurality of services that are time-multiplexed and transmitted, the UTRAN controls transmission and reception of the respective services. That is, the UTRAN transmits time information indicating whether various services are transmitted to the terminal.
In the present invention, if the QoS type of the MBMS service can be classified into a background type, the UTRAN can transmit a plurality of MBMS services through a designated physical channel and a designated transport channel. Accordingly, the UTRAN should determine whether to schedule the MBMS service to be transmitted on the physical/transport channel according to the QoS type of the MBMS service before the MBMS service set on the cell. If the QoS types of the MBMS services are all background types, the UTRAN transmits different MBMS services at different transmission intervals.
Fig. 5 shows a method for transmitting an MBMS service according to the present invention. A plurality of background type services (MBMS service 1 and MBMS service 2) can be transmitted on one channel using a time multiplexing method. In this case, this channel refers to a transport channel or a physical channel.
Specifying transmission interval of MBMS data by control plane
The Radio Resource Control (RRC) layer of UTRAN first determines a certain time to transmit a specific MBMS data. That is, the UTRAN RRC determines a frame of a common physical channel suitable for transmitting the designated MBMS data. For example, the UTRAN RRC determines a time period during which the specified multimedia service data can be continuously transmitted and a time interval repetition period. The time interval represents the number of frames in a continuous group of frames in which the specified multimedia service data is transmitted. The time interval repetition period denotes an interval between the start of a certain consecutive frame group and the start of the next frame group.
This approach is similar to the first level subscription of conventional CBS services. However, the subscription of the present invention differs from the conventional subscription in that different subscription parameters are set for providing an MBMS service for one cell.
Fig. 6 shows an example of MBMS scheduling according to the present invention.
Referring to fig. 6, logical channels (MTCH #1, MTCH #2, and MTCH #3) adapted to transmit MBMS data provide different MBMS services of a background class. Various logical channels transmit user data of various MBMS services. The logical channel adapted to transmit MBMS control information (MCCH) provides predetermined information for different MBMS services.
Fig. 6 shows how MTCH is allocated to a radio frame or transmission time interval. As shown in fig. 6, the UTRAN may allocate data 1 of MTCH #1, data 2 of MTCH #2, and data 3 of MTCH #3 to different radio frames or transmission time intervals. The UTRAN transmits predetermined information including allocation to the terminal through the MCCH. Accordingly, the terminal needs to receive predetermined information through the MCCH to acquire time information on transmitting data of one or more MBMS services of interest through one MTCH.
The RRC layer of UTRAN determines a certain time to transmit a specific MBMS data and sets a process of actual data transmission.
Fig. 7 shows a time information setting method suitable for transmitting MBMS data through a control layer.
As shown in fig. 7, the UTRAN RRC allocates a frame suitable for transmitting a physical channel designating MBMS data (step S10). That is, the UTRAN RRC determines a frame suitable for the designated MBMS service and delivers corresponding frame allocation information to the next layer (physical layer).
In addition, the UTRAN RRC delivers frame allocation information to the RRC of the terminal group that desires to receive the corresponding MBMS service. In this case, the frame allocation information may be transferred using the control plane through a broadcast channel (BCCH) or a control channel (CCCH or DCCH).
The terminals RRC of the terminal group transfers the received frame allocation information to the physical layer of each terminal (step S12), and then the physical layer of each terminal stores the received frame allocation information, thereby completing the setting of the transmission time information of the MBMS data through the control layer.
When the UTRAN sets or resets a Radio Bearer (RB) suitable for the designated MBMS service, the time information setting process shown in fig. 7 can be performed.
In a different embodiment, the time information setting process may be dynamically performed while transmitting data specifying the MBMS service. That is, the radio system may perform the time information setting process a plurality of times periodically or non-periodically while setting the RB designating the MBMS service.
In the present invention, a terminal receiving data of a specified MBMS service may also receive signals or data of different MBMS services or signals or data of different services other than MBMS.
Fig. 8 shows a process in which terminals in a terminal group receive paging information between receiving MBMS data.
This process is based on the assumption that a frame suitable for the specified MBMS service has been allocated by the process shown in fig. 7.
The physical layer of the UTRAN receives MBMS data applicable to the designated MBMS service from the upper layer and delivers the data (steps S20 and S21). At this time, the UTRAN controls to transmit MBMS data only in the allocated frame.
The physical layer of the terminal belonging to the terminal group receiving the corresponding MBMS service accepts MBMS data in a frame in response to the pre-stored frame allocation information and delivers the data to the higher layer of the user plane (step S22).
For other frames that do not respond to the pre-stored frame allocation information, the terminal group may receive other channels that are not MTCH channels for the designated MBMS service. The UTRAN RRC transmits a paging signal to the RRC of the terminal belonging to the terminal group. At this time, the UTRAN delivers the paging signal in a time period in which the terminal can effectively receive, i.e., in other times than the time period allocated for the designated MBMS service (step S23). The paging signal may be transmitted and received using RLC, MAC, and a service of a physical layer located at a lower side of RRC.
Thereafter, the steps S24-S28 are repeatedly performed for the time period allocated for the designated MBMS service, and the terminals belonging to the terminal group receive MBMS data.
In other periods other than the period assigned to the designated MBMS service, the terminal may perform Discontinuous Reception (DRX) or receive a control signal, for example, a Short Message Service (SMS) message, for a service such as paging or not an MBMS.
Specifying transmission part of MBMS data by control plane
When MBMS data is to be transmitted over the control plane, the multimedia broadcast and multicast control layer (referred to herein as the "multimedia layer") of the UTRAN determines a certain time at which the specified MBMS data is to be transmitted. That is, the multimedia layer determines a frame of a common physical channel suitable for transmitting the designated MBMS data and constructs an MBMS scheduling message similar to the conventional BMS scheduling message.
Unlike the prior art in which one cell generates only one BMS scheduling message, in the present invention, one cell can generate as many MBMS scheduling messages as MBMS services. That is, different MBMS services provided in one cell use different MBMS scheduling messages.
An MBMS scheduling message applicable to a specified MBMS service may be transmitted to a terminal group through the MTCH. Thus, different MBMS scheduling messages applicable to different MBMS services can be transmitted to the terminal group through different MTCHs.
An MBMS scheduling message includes a sequence number, identifier or transmission time information of a designated MBMS data to be broadcasted or multicasted. The terminals in the terminal group receive the MBMS scheduling message and specify the data to be received next and the frame in which the data is located. Subsequently, based on the described information, the terminal can efficiently carry out a reception processing procedure.
In order to ensure reliability of MBMS data transmission, the UTRAN may repeatedly transmit the same data. In this case, the MBMS scheduling message may inform whether the corresponding MBMS is first transmitted or has been repeatedly transmitted. When a specific MBMS is provided, the MBMS scheduling message may be transmitted periodically or non-periodically a plurality of times. In this case, the information of the transmitted MBMS scheduling message is not the same each time.
In one embodiment, the MBMS scheduling message may be constructed in the following manner.
When an RB is set for a designated MBMS service, an MBMS scheduling message may be transmitted multiple times at a certain period. The MBMS scheduling message (M1) transmitted for the first time delivers transmission information of MBMS data until the next MBMS scheduling message (M2) is to be transmitted. That is, for the designated MBMS service, M1 transfers transmission information of MBMS data between points in time when M1 and M2 are transferred.
The terminal group periodically receives the MBMS scheduling message and recognizes whether data is received before transmitting the next scheduling message. The period of the MBMS scheduling message may be determined by the radio system and transmitted to the terminal group when the MBMS RB is set or reset.
In another embodiment, the MBMS scheduling message may be constructed in the following manner.
The MBMS scheduling message may be transmitted a plurality of times aperiodically when setting an RB for a designated MBMS service. Similar to the BMC scheduling message, the MBMS scheduling message includes a length of the MBMS scheduling period and start point information of the MBMS scheduling period. The length of the predetermined period indicates a length between a start point of the MBMS predetermined period, which indicates a difference between a transmission time point of the MBMS predetermined message and a start time point of the next MBMS predetermined period, and an end point of the MBMS predetermined period after the MBMS predetermined message.
Accordingly, a terminal receiving the MBMS message can recognize the start and end of a transmission MBMS scheduling period to be started later by receiving the MBMS scheduling message. The terminal may obtain information of a next MBMS scheduling period according to the MBMS scheduling message received during the MBMS scheduling period.
In this way, the multimedia layer of UTRAN determines a certain time when data of a specific MBMS service is to be transmitted, and can set the transmission of actual data.
Fig. 9 illustrates a time information setting method suitable for transmitting MBMS data through a user layer.
As shown in fig. 9, the multimedia layer of the UTRAN composes an MBMS scheduling message, which may include time information of when specific data suitable for a specific MBMS is transmitted (step S30), and delivers the message to the multimedia layer of a terminal group that needs to receive the corresponding MBMS (step S31). The MBMS scheduling message may be delivered through a lower layer of the multimedia layer.
The multimedia layer of the terminal interprets the received MBMS scheduling message. The multimedia layer of the terminal may obtain time information (predetermined information) of transmission of the specified data to be received from the predetermined message and transfer the obtained predetermined information to the terminal RRC (step S32). Subsequently, the terminal RRC transfers the predetermined information to the physical layer of the terminal (step S33), and the terminal physical layer stores the predetermined information (step S34). The stored predetermined information may be used to designate the reception of MBMS data.
The time information setting process shown in fig. 9 may be dynamically generated while performing the designated MBMS data transmission. That is, the wireless system may perform the time information setting process periodically or aperiodically a plurality of times while setting the RB designating the MBMS service.
In the present invention, a terminal receiving data of a specific MBMS service may also receive signals or data of a different MBMS service, or signals or data of other services other than MBMS.
Fig. 10 illustrates that terminals in a terminal group receiving designated MBMS data receive different services between the received MBMS data. This process is based on the process procedure of assuming that the time information of the allocation designation MBMS shown in fig. 9 has been performed.
First, the physical layer of the UTRAN receives MBMS data applicable to a designated MBMS from an upper layer (step S40) and then transmits the received MBMS data (step S41). At this time, the UTRAN can control the MBMS data of the corresponding service to be transmitted according to the contents of the predetermined message.
The physical layer belonging to the terminal in the terminal group receiving the corresponding MBMS service receives the MBMS data in the frame indicated by the stored predetermined information and transfers it to the upper layer (step S42).
The terminal group may receive other channels than the MTCH channel designating the MBMS service when one frame does not respond to the stored reservation information. For this, the UTRAN may send a Short Message Service (SMS) message to the RRC of some terminals belonging to the terminal group (step S43). Preferably, the UTRAN may transmit the SMS message for an effective period of time so that the terminal may receive in other periods of time not allocated for the designated MBMS service.
Thereafter, the steps S44-S46 shown in fig. 10 may be repeatedly performed for the allocated time period for the next designated MBMS service so that the terminal physical layer can receive MBMS data. The terminal may perform a Discontinuous Reception (DRX) operation or receive a control signal, for example, paging or other traffic such as an SMS message service that is not an MBMS.
As mentioned above, the setting of the time information shown in fig. 7 is performed only when setting or resetting the RB applicable to the specified MBMS service. After setting or resetting the RB, the setting of the time information may be periodically or non-periodically performed a plurality of times while the MBMS data is transmitted, as shown in fig. 9. The allocated frame shown in fig. 9 may be selectively allocated again in the allocated frame shown in fig. 7.
Thus, the method shown in fig. 7 can be used for static reservation, while the method shown in fig. 9 can be used for dynamic reservation. Before data transmission, both UTRAN and terminal need to perform the processes shown in fig. 7 and 9.
After the processes shown in fig. 7 and 9 are performed, as shown in fig. 8 and 10, the corresponding MBMS data may be received in the time period allocated for the designated MBMS service, and at the same time, a control signal or other data such as an SMS message that is not the designated MBMS service may be received in the time period not allocated.
As discussed above, the conventional CBS scheduling method is designed to be suitable for receiving a control signal or performing DRX while receiving CBS traffic. This method is also required to be applied to MBMS, but the method of setting the same predetermined parameter in one cell is similar to the conventional method, which cannot be applied to MBMS service.
In the present invention, the data transmission time can be set to be different for each MBMS service. Therefore, each terminal belonging to the terminal group can receive other services or other channels at a certain time when data of the designated MBMS service is not transmitted. In addition, in a time period when MBMS service data is transmitted, if other services or channels are not received, terminals belonging to a corresponding terminal group may become an idle state, thereby preventing battery consumption of the terminals.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention in any way. The present techniques may be applied relatively quickly to other types of devices. The discussion of the present invention is intended to be illustrative and explanatory only and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures discussed herein as performing the recited function and not only structural equivalents, but also equivalent structures.