Terminal device, network device and group communication method

TECHNICAL FIELD

0001Embodiments of the present invention relate to the field of mobile communications, and in particular, to a terminal device, a network device, and group communication methods.

BACKGROUND

0002Group communication refers to a mechanism for mutual communication between a group of UEs. During group communication, only one UE in a group of UEs is allowed to speak, and the other UEs receive voice content of the speaking UE over a downlink. Currently, group communication is usually implemented by using a group communications server. Each UE in a group of UEs establishes a signaling connection and a voice connection to a group server, so as to implement group communication. The group communications server authorizes, by using signaling, a UE to speak, and transmits downlink voices of the speaking UE to the other UEs in the group. When a UE needs to speak, the UE requests the group communications server for the floor by using Session Initiation Protocol (English: Session Initiation Protocol, SIP for short) signaling. Only after the group communications server gives the floor to the UE, the speaking UE can send voices to the other UEs in the group. Similarly, the group communications server instructs, by using SIP signaling, the other UEs in the group to start to listen to the talk.

0003Among current implementation manners of group communication, the simplest implementation manner is to implement group communication by using a same processing manner as that for normal voice communication. That is, each UE on an access network side requires a separate downlink voice channel for transmitting a voice message. Such a processing manner requires each UE to separately send a same voice message. Consequently, radio resources are wasted. <patcit id="pcit0001" dnum="US2012236776A1"><text>US 2012236776 A1</text></patcit> discloses that transfer of Multimedia Broadcast/Multicast Services (MBMS) over a Single Frequency Network (MBSFN) service and idle mode unicast service for a mobile entity from a source base station to a target base station may be managed by a base station or mobile entity of a cellular wireless communications system (WCS). Operations related to the transfer may include obtaining an MBMS status of the mobile entity, and/or obtaining MBMS support information for the base station. A network entity may facilitate MBMS discovery by a mobile entity, by transmitting a data element to the mobile entity including service identifiers mapped to corresponding cell identifiers to indicate respective MBMS services to be broadcast in an WCS area on adjacent cells identified by respective ones of the cell identifiers.; The MBMS services may be broadcast within the WCS area using the adjacent cells previously indicated in the data element. <patcit id="pcit0002" dnum="US2014286222A1"><text>US 2014286222 A1</text></patcit> discloses a method of supporting group communication over LTE MBMS. A UE first establishes a unicast Evolved Packet Service (EPS) bearer in an LTE network for group communication. The UE belongs to a communication group having a communication group ID. The UE receives access information from the network for monitoring downlink (DL) multicast traffic of the DL group communication based on a multicast decision. The UE is then ready for monitoring a MBMS bearer for receiving the DL multicast traffic. The multicast MBMS bearer is associated with TMGI, and wherein the TMGI is associated with the communication group ID.

SUMMARY

0004The present invention provides a terminal device of claim 1, a network device of claim 5, and group communication methods of claims 8 and 11, to implement group communication. Further embodiments of the invention are defined by the dependent claims.

0005According to a first aspect, a terminal device is provided, including: a first receiving module, the first receiving module being configured to receive a first message sent by a network device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service; and a second receiving module, the second receiving module being configured to receive, according to the first message received by the first receiving module, a first group service corresponding to a first group service identifier of the terminal device.

0006With reference to the first aspect, in a first possible implementation manner of the first aspect, the terminal device includes: a third receiving module, the third receiving module being configured to receive configuration information of the first message, so that the first receiving module of the terminal device receives the first message according to the configuration information of the first message, where the configuration information of the first message received by the third receiving module includes at least one of the following information: a time pattern that is used by the network device to send the first message, a first RNTI, and a modulation and coding scheme of the first message.

0007With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the time pattern that is used by the network device to send the first message and that is received by the third receiving module includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0008With reference to the first or the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the first receiving module includes a first receiving unit, where when the configuration information received by the third receiving module includes the first RNTI, the first receiving unit is configured to receive first downlink control information according to the first RNTI, so as to receive the first message according to the first downlink control information; or when the configuration information received by the third receiving module does not include the first RNTI, the first receiving unit is configured to receive the first downlink control information according to the first default RNTI, so as to receive the first message according to the first downlink control information.

0009With reference to any one of the first aspect or the first to the third possible implementation manners of the first aspect, in a fourth possible implementation manner of the first aspect, when the at least one group service identifier includes the first group service identifier of the terminal device, the second receiving module is configured to receive the first group service according to the first message received by the first receiving module.

0010With reference to any one of the first aspect or the first to the fourth possible implementation manners of the first aspect, in a fifth possible implementation manner of the first aspect, the first message received by the first receiving module further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a second RNTI, and a logical channel number of each group service.

0011With reference to any one of the first aspect or the first to the fifth possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the second receiving module includes a second receiving unit, where when the first message includes the second RNTI, the second receiving unit is configured to receive second downlink control information according to the second RNTI, so as to receive the first group service according to the second downlink control information; or when the first message does not include the second RNTI, the second receiving unit is configured to receive the second downlink control information according to a second default RNTI, so as to receive the first group service according to the second downlink control information.

0012With reference to the sixth possible implementation manner of the first aspect, in a seventh possible implementation manner of the first aspect, the second receiving module further includes a third receiving unit, the third receiving unit being configured to: receive a MAC PDU according to the second downlink control information received by the second receiving unit; and when the first message received by the first receiving module includes the logical channel number of each group service, receive, according to a logical channel number of the first group service received by the first receiving module, a MAC SDU of the first group service received by the second receiving module; or when the first message received by the first receiving module does not include the logical channel number of each group service, receive, according to the first group service identifier, a MAC SDU of the first group service received by the second receiving module.

0013With reference to the seventh possible implementation manner of the first aspect, in an eighth possible implementation manner of the first aspect, the MAC PDU received by the second receiving module carries a MAC CE, to indicate that the first group service ends.

0014With reference to any one of the first aspect or the first to the seventh possible implementation manners of the third aspect, in a ninth possible implementation manner of the first aspect, the terminal device further includes: a determining module, the determining module being configured to determine, according to change indication information, that the first message received by the first receiving module is changed, where the change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in an SIB1 message; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the second receiving module receives the first downlink control information.

0015With reference to any one of the first aspect or the first to the ninth possible implementation manners of the first aspect, in a tenth possible implementation manner of the first aspect, the first receiving module is further configured to: if the terminal device does not store the first message, receive the first message at a moment at which the network device sends the multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receive a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message.

0016According to a second aspect, a network device is provided, including: a first sending module, the first sending module being configured to send a first message to a terminal device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service; and a second sending module, the second sending module being configured to send a group service corresponding to the at least one group service identifier to the terminal device.

0017With reference to the second aspect, in a first possible implementation manner of the second aspect, the network device further includes a third sending module, the third sending module being configured to: send configuration information of the first message, so that the terminal device receives the first message according to the configuration information of the first message, where the configuration information of the first message includes at least one of the following information: a time pattern for sending the first message, a first RNTI, and a modulation and coding scheme of the first message.

0018With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the time pattern for sending the first message by the third sending module includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0019With reference to any one of the second aspect or the first or the second possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the first message sent by the first sending module further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service in the at least one group service, a second RNTI, and a logical channel number of each group service.

0020With reference to any one of the second aspect or the first or the second possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the first sending module is further configured to: send indication information indicating that the first message is changed to the terminal device, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device.

0021According to a third aspect, a group communication method is provided, including: receiving, by a terminal device, a first message sent by a network device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service; and receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device.

0022With reference to the third aspect, in a first possible implementation manner of the third aspect, the method includes: receiving, by the terminal device, configuration information of the first message, so as to receive the first message according to the configuration information of the first message, where the configuration information of the first message includes at least one of the following information: a time pattern that is used by the network device to send the first message, a first RNTI, and a modulation and coding scheme of the first message.

0023With reference to the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the time pattern that is used by the network device to send the first message includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0024With reference to the first or the second possible implementation manner of the third aspect, in a third possible implementation manner of the third aspect, the receiving, by the terminal device, configuration information of the first message, so as to receive the first message according to the configuration information of the first message includes: when the configuration information includes the first RNTI, receiving, by the terminal device, first downlink control information according to the first RNTI, so as to receive the first message according to the first downlink control information; or when the configuration information does not include the first RNTI, receiving, by the terminal device, the first downlink control information according to a first default RNTI, so as to receive the first message according to the downlink control information.

0025With reference to any one of the third aspect or the first to the third possible implementation manners of the first aspect, in a fourth possible implementation manner of the third aspect, when the at least one group service identifier includes the first group service identifier of the terminal device, the terminal device receives the first group service according to the first message.

0026With reference to any one of the third aspect or the first to the fourth possible implementation manners of the third aspect, in a fifth possible implementation manner of the third aspect, the first message further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service in the at least one group service, a second RNTI, and a logical channel number of each group service.

0027With reference to any one of the third aspect or the first to the fifth possible implementation manners of the third aspect, in a sixth possible implementation manner of the third aspect, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the second RNTI, receiving, by the terminal device, second downlink control information according to the second RNTI, so as to receive the first group service according to the second downlink control information; or when the first message does not include the second RNTI, receiving, by the terminal device, the second downlink control information according to a second default RNTI, so as to receive the first group service according to the second downlink control information.

0028With reference to the sixth possible implementation manner of the third aspect, in a seventh possible implementation manner of the third aspect, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: receiving, by the terminal device, a MAC PDU according to the second downlink control information; and when the first message includes the logical channel number of each group service, receiving, by the terminal device, a MAC SDU of the first group service according to a logical channel number of the first group service in the logical channel number of each group service; or when the first message does not include the logical channel number of each group service, receiving, by the terminal device, a MAC SDU of the first group service according to the first group service identifier.

0029With reference to the seventh possible implementation manner of the third aspect, in an eighth possible implementation manner of the third aspect, the MAC PDU carries a MAC CE, to indicate that the first group service ends.

0030With reference to any one of the third aspect or the first to the eighth possible implementation manners of the third aspect, in a ninth possible implementation manner of the third aspect, the method further includes: determining, by the terminal device according to change indication information, that the first message is changed, where the change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in an SIB1 message; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the terminal device receives the first downlink control information.

0031With reference to any one of the third aspect or the first to the ninth possible implementation manners of the third aspect, in a tenth possible implementation manner of the third aspect, the receiving, by a terminal device, a first message sent by a network device includes: if the terminal device does not store the first message, receiving the first message at a moment at which the network device sends the multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receiving a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message.

0032According to a fourth aspect, a group communication method is provided, including: sending a first message to a terminal device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service; and sending the at least one group service to the terminal device.

0033With reference to the fourth aspect, in a first possible implementation manner of the fourth aspect, the method further includes: sending configuration information of the first message, so that the terminal device receives the first message according to the configuration information of the first message, where the configuration information of the first message includes at least one of the following information: a time pattern for sending the first message, a first RNTI, and a modulation and coding scheme of the first message.

0034With reference to the first possible implementation manner of the fourth aspect, in a second possible implementation manner of the fourth aspect, the time pattern for sending the first message includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0035With reference to any one of the fourth aspect or the first to the second possible implementation manners of the fourth aspect, in a third possible implementation manner of the fourth aspect, the first message further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a second RNTI, and a logical channel number of each group service.

0036With reference to any one of the fourth aspect or the first to the third possible implementation manners of the fourth aspect, in a fourth possible implementation manner of the fourth aspect, the method further includes: sending indication information indicating that the first message is changed to the terminal device, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device.

0037Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

BRIEF DESCRIPTION OF DRAWINGS

0038To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly describes the accompanying drawings required for describing the embodiments of the present invention. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> is a schematic block diagram of a terminal device according to an embodiment of the present invention;</li><li><figref idref="f0002">FIG. 2</figref> is a schematic block diagram of a terminal device according to another embodiment of the present invention;</li><li><figref idref="f0003">FIG. 3</figref> is a schematic block diagram of a network device according to an embodiment of the present invention;</li><li><figref idref="f0004">FIG. 4</figref> is a schematic block diagram of a network device according to another embodiment of the present invention;</li><li><figref idref="f0005">FIG. 5</figref> is a schematic flowchart of a group communication method according to an embodiment of the present invention;</li><li><figref idref="f0005">FIG. 6</figref> is a schematic flowchart of a group communication method according to another embodiment of the present invention;</li><li><figref idref="f0006">FIG. 7</figref> is a schematic flowchart of a group communication method according to still another embodiment of the present invention;</li><li><figref idref="f0007">FIG. 8</figref> is a schematic flowchart of a group communication method according to still another embodiment of the present invention;</li><li><figref idref="f0008">FIG. 9</figref> is a schematic block diagram of a terminal device according to another embodiment of the present invention; and</li><li><figref idref="f0008">FIG. 10</figref> is a schematic block diagram of a network device according to another embodiment of the present invention.</li></ul>

DESCRIPTION OF EMBODIMENTS

0039The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

0040It should be understood that in the embodiments of the present invention, a terminal equipment (English: Terminal Equipment) may be user equipment (English: User Equipment, UE for short), a customer premise equipment (English: Customer Premise Equipment, CPE for short), a mobile station (English: Mobile Station, MS for short), a mobile terminal (English: Mobile Terminal), or the like. The terminal equipment may communicate with one or more core networks by using a radio access network (English: Radio Access Network, RAN for short). For example, the terminal equipment may be a mobile phone (or referred to as a "cellular" phone), or a computer with a mobile terminal. For example, the terminal equipment may be a portable, pocket-sized, handheld, computer built-in, or in-vehicle mobile apparatus, and it exchanges voice and/or data with the radio access network. However, the present invention is not limited thereto. For ease of description, UE is used as an example in the following embodiments.

0041In the embodiments of the present invention, the network device may be a base station, an enhanced base station, a cell, a relay, or the like. The base station may be an evolved Node B (English: Evolutional Node B, eNB or e-NodeB for short) in LTE, and is not limited in the present invention. For convenience of description, the following embodiments are described by using an eNB as an example.

0042It should be understood that, the terms "system" and "network" may be used interchangeably in this specification. The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, the character "/" in this specification generally indicates an "or" relationship between the associated objects.

0043<figref idref="f0001">FIG. 1</figref> is a schematic block diagram of a terminal device 100 according to an embodiment of the present invention. As shown in <figref idref="f0001">FIG. 1</figref>, the terminal device 100 includes a first receiving module 110 and a second receiving module 120.

0044The first receiving module 110 is configured to receive a first message sent by a network device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service.

0045The second receiving module 120 is configured to receive, according to the first message received by the first receiving module 110, a first group service corresponding to a first group service identifier of the terminal device 100.

0046Specifically, the first message sent by the network device may include a group service identifier list. The group service identifier list includes a group service identifier of at least one group service to be sent by the network device. The group service identifier list may include one or more group service identifiers, and one group service identifier corresponds to one group service. It should be understood that the first message may be an independent broadcast message, or may be carried in a form of specific information in another broadcast message. Specifically, the first message may be a multicast control channel (English: Multicast Control Channel, MCCH for short) message, a group configuration message, a multicast control message, or a multicast configuration message, and the present invention is not limited thereto. Specifically, the group service identifier list may be a temporary mobile group identity (English: Temporary Mobile Group Identity, TMGI for short) list including a TMGI corresponding to the at least one group service, and the present invention is not limited thereto. The first group service identifier of the terminal device 100 refers to a group service identifier of interest to or a group service identifier subscribed to by the terminal device 100. Specifically, the terminal device 100 obtains, from a user service description (English: user service description, USD for short), the group service identifier of interest or the subscribed group service identifier.

0047In the second receiving module 120, the terminal device distinguishes and identifies, according to a group service identifier in the first message, a group service needing to be received. In this way, the terminal device receives a group service intended to be received.

0048Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0049Optionally, in an embodiment of the present invention, <figref idref="f0002">FIG. 2</figref> is a schematic block diagram of a terminal device 200 according to an embodiment of the present invention. As shown in <figref idref="f0002">FIG. 2</figref>, the terminal device 200 includes a first receiving module 210, a second receiving module 220, and a third receiving module 230.

0050The first receiving module 210 is configured to receive a first message sent by a network device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service.

0051The second receiving module 220 is configured to receive, according to the first message received by the first receiving module 210, a first group service corresponding to a first group service identifier of the terminal device 200.

0052The third receiving module 230 is configured to receive configuration information of the first message, so that the first receiving module of the terminal device receives the first message according to the configuration information of the first message. The configuration information of the first message received by the third receiving module includes at least one of the following information: a time pattern that is used by the network device to send the first message, a modulation and coding scheme of the first message, and a first RNTI. The modulation and coding scheme of the first message may be specifically as follows: For example, a modulation scheme of the first message is quadrature phase shift keying (English: Quadrature Phase Shift Keying, QPSK for short), and a coding scheme is 1/3 coding; or a modulation scheme of the first message is QPSK, and a coding scheme is 1/2 coding. It should be understood that other coding or modulation schemes may also be used, and the present invention is not limited thereto. The first RNTI refers to an RNTI used by the network device to schedule and send the first message.

0053Optionally, in an embodiment of the present invention, the time pattern that is used by the network device to send the first message and that is received by the third receiving module includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message. The change period T' of the first message is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. A quantity of repetition times for sending the first message represents a number of times the first message is repeatedly sent within one change period T', and for example, may be specifically 2, 4, 6, 8, or the like. The time offset of the first message is, for example, 0 ms, 1 ms, 2 ms, 3 ms, or the like. When the time pattern of the first message does not include the time offset of the first message, the time offset of the first message is a fixed value of, for example, 0 or 1. It should also be understood that the values listed above are merely examples, other possible values of the change period T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0054Optionally, in an embodiment of the present invention, the first receiving module further includes a first receiving unit.

0055When the configuration information received by the third receiving module includes the first RNTI, the first receiving unit is configured to receive first downlink control information according to the first RNTI. When the configuration information received by the third receiving module does not include the first RNTI, the first receiving unit is configured to receive first downlink control information according to a first default RNTI. Specifically, if the configuration information includes the first RNTI, the terminal device parses the first downlink control information according to an RNTI corresponding to the first group service in the first RNTI, so as to receive the first message according to the first downlink control information. If the first message does not include the first RNTI, the terminal device receives the first downlink control information according to the first default RNTI. The first downlink control information is downlink control information used to schedule the first message. The first default RNTI is a default RNTI used by the network device to schedule and send the first message. For example, the first default RNTI may be FFF4, FFFC, or the like, and the present invention is not limited thereto.

0056Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0057Optionally, in an embodiment of the present invention, when the at least one group service identifier sent by the network device includes the first group service identifier of the terminal device, the second receiving module of the terminal device is configured to receive the first group service according to the first message received by the first receiving module.

0058It should be understood that when the group service identifier list sent by the network device does not include a group service identifier of the terminal device, the terminal device does not receive group service data sent by the network device, and only when the group service identifier list sent by the network device includes a group service identifier of the terminal device, the terminal device receives group service data that is sent by the network device and that corresponds to the group service identifier of the terminal device. For example, when group services to be sent by the network device are group service A, group service B, and group service C, the group service identifier list includes three group service identifiers A, B, and C. Three group service identifiers A, B, and D may be marked in advance for the terminal device according to a requirement of the terminal device. In this case, the terminal device receives only service A and service B that are sent by a network side device, and cannot receive service C.

0059Optionally, in an embodiment of the present invention, the first message received by the first receiving module further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second radio network temporary identifier (English: Radio Network Temporary Identifier, RNTI for short). The period T for sending the first message by the network device represents frequency at which the first message is used to send a message. Specifically, the period T may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. For the change period T' of the first message, the period T' is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. The logical channel number of each group service that is sent by the network device is used to represent a logical channel used by the group service. The logical channel number may be represented by 12 bits, for example, 000000000001, or by 5 bits, for example, 00001, or by any bit quantity ranging from 6 to 13. The bit quantity used may be a length preset by a network, or a length indicated by the first message. The second RNTI refers to an RNTI used to schedule the group service sent by the network device. It should be understood that the second RNTI may refer to one RNTI used to schedule multiple group services, or may refer to different RNTIs used to schedule multiple group services. That is, each group service has a corresponding RNTI, and each RNTI may correspond to one or more group services, and the present invention is not limited thereto. It should also be understood that the values listed above are merely examples, other possible values of the period T or T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0060Optionally, in an embodiment of the present invention, the second receiving module of the terminal device includes a second receiving unit. When the first message sent by the network device includes the second RNTI, the second receiving unit is configured to receive second downlink control information (English: Downlink Control Information, DCI for short) according to the second RNTI. When the first message does not include the second RNTI, the second receiving unit is configured to receive second downlink control information according to a second default RNTI. Specifically, if the terminal device needs to receive the first group service corresponding to the first group service identifier when the first message includes the second RNTI, the terminal device parses the second downlink control information according to an RNTI corresponding to the first group service in the second RNTI, so as to receive the first group service according to the second downlink control information. If the first message does not include the second RNTI, the terminal device receives the second downlink control information according to the second default RNTI. The second downlink control information is downlink control information used to schedule group service data sent by the network device. The second default RNTI is a default RNTI used to schedule the group service sent by the network device. For example, the second default RNTI may be FFF4, FFFC, or the like, and the present invention is not limited thereto.

0061Specifically, the receiving second downlink control information according to the second RNTI or a second default RNTI is: parsing, at a scheduling time corresponding to the first group service, the second downlink control information that is scrambled with the RNTI of the first group service. The scheduling time of the first group service is a moment that is obtained by performing a modulo operation on the period T by using a sum of a system frame number* 10 and a subframe index of the first group service and that is equal to the time offset corresponding to the first group service.

0062Optionally, in an embodiment of the present invention, the second receiving module further includes a third receiving unit, the third receiving unit being configured to: receive, according to the second downlink control information received by the second receiving unit, a Media Access Control packet data unit (English: Media Access Control Packet Data Unit, MAC PDU for short) received by the second receiving module; and when the first message received by the first receiving module includes the logical channel number of each group service in the at least one group service, obtain, according to a logical channel number of the first group service in the at least one group service received by the second receiving unit, a Media Access Control service data unit (English: Media Access Control Service Data Unit, MAC SDU for short) received by the second receiving module; or when the first message received by the first receiving module does not include the logical channel number of each group service in the at least one group service, obtain, according to the first group service identifier, a MAC SDU of the first group service received by the second receiving module. It should be understood that the MAC PDU refers to a packet data unit including a MAC SDU of the at least one group service, and the present invention is not limited thereto.

0063Specifically, for example, when the first message received by the terminal device includes logical channel numbers A, B, and C of group service A, group service B, and group service C that are sent by the network device, a corresponding channel A can be found by using the channel number A corresponding to group service A, the channel number B corresponding to group service B and channel C corresponding to group service C, and a MAC SDU received by the second receiving module is obtained. In this case, if the first message does not include the logical channel numbers, group services A, B, and C all obtain, according to their group service identifiers and by using a channel allocated to an entire group service, a MAC SDU that corresponds to the group service and that is received by the second receiving module.

0064In an embodiment of the present invention, optionally, the MAC PDU received by the second receiving module carries a Media Access Control (English: Media Access Control Control Element, MAC CE for short), to indicate that the first group service ends. The MAC PDU including the MAC CE indicating that the service ends may be sent once, or may be repeatedly sent multiple times, for example, three times or five times, so as to improve receiving reliability of the terminal device. A specific implementation manner may be that the MAC CE includes a group service identifier or a logical channel number of a group service sent by the terminal device, and when the terminal device receives a MAC CE including a particular group service identifier or logical channel number, it is considered that the service ends. Alternatively, a specific implementation manner may be that when the MAC CE does not include a group service identifier or a logical channel number corresponding to a group service sent by the terminal device, it is considered that all group services included in the MAC PDU that includes the MAC CE indicating that the service ends end. It should be understood that the numerals mentioned in this embodiment of the present invention are merely examples. It should also be understood that the MAC CE is a MAC control unit indicating that the at least one group service ends, and the present invention is not limited thereto.

0065In an embodiment of the present invention, optionally, the terminal device further includes: a determining module. The determining module is configured to determine, according to a change indication message, that the first message received by the first receiving module is changed. The change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in a system information block 1 (English: System Information Block 1, SIB1 for short); or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the second receiving module receives the first downlink control information. The change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the downlink control information of the first message may be specifically a label value, whose length may be 4 bits, 5 bits, or the like. The downlink control information may be in a format such as 1/1A/1C. Further, the terminal device compares a stored label value with the label value in the change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the downlink control information of the first message. If they are different, it is considered that the first message is changed. It should be understood that the length values of the foregoing representation value are merely examples, and the present invention is not limited thereto.

0066In an embodiment of the present invention, optionally, the first receiving module is further configured to: if the terminal device does not store the first message, receive the first message at a moment at which the network device sends multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receive a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message. If the terminal device does not store the first message, the terminal device needs to attempt to receive the first message at each first message sending moment, until one first message is correctly received. The terminal device may obtain the first message sending moment by using an SIB1 message, or obtain the first message sending moment from the configuration information of the first message scheduled by the downlink control information, so as to attempt to receive the first message at the first message sending moment. If the terminal device already stores the first message, when determining that the first message is changed, the terminal device needs to start to receive a changed first message after the change period T' has elapsed, so as to receive the first group service according to the changed first message.

0067Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, when the network device sends the first message for a quantity of times that equals to the repetition coefficient in one change period T', different redundancy versions may be used each time the first message is sent. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0068Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, the first message is sent in N consecutive subframes starting from a subframe corresponding to each first message scheduling moment. The first messages sent in the subframes may be the same, or different redundancy versions may be used. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0069Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0070The terminal device according to the embodiments of the present invention is described in detail above with reference to <figref idref="f0001">FIG. 1</figref> and <figref idref="f0002">FIG. 2</figref>. A network device according to the embodiments of the present invention is described in detail below with reference to <figref idref="f0003">FIG. 3</figref> and <figref idref="f0004">FIG. 4</figref>.

0071<figref idref="f0003">FIG. 3</figref> is a schematic block diagram of a network device according to an embodiment of the present invention. As shown in <figref idref="f0003">FIG. 3</figref>, the network device includes a first sending module 310 and a second sending module 320.

0072The first sending module 310 is configured to send a first message to a terminal device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service.

0073The second sending module 320 is configured to send a group service corresponding to the at least one group service identifier to the terminal device.

0074Specifically, the first message sent by the first sending module 310 of the network device may include a group service identifier list. The group service identifier list includes a group service identifier of at least one group service to be sent by the network device. The group service identifier list may include one or more group service identifiers, and one group service identifier corresponds to one group service. It should be understood that the first message may be an independent broadcast message, or may be carried in a form of specific information in another broadcast message. Specifically, the first message may be an MCCH message or a group configuration message, and the present invention is not limited thereto. Specifically, the group service identifier list may be a TMGI list including a TMGI corresponding to the at least one group service, and the present invention is not limited thereto. The group service sent by the second sending module 320 of the network device is group services corresponding to one or more group service identifiers included in the group service identifier list. One group service identifier corresponds to one group service.

0075Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0076Optionally, in an embodiment of the present invention, <figref idref="f0004">FIG. 4</figref> is a schematic block diagram of a network device according to another embodiment of the present invention. The network device includes a first sending module 410, a second sending module 420, and a third sending module 430.

0077The first sending module 410 is configured to send a first message to a terminal device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service.

0078The second sending module 420, the second sending module is configured to send a group service corresponding to the at least one group service identifier to the terminal device.

0079The third sending module 430 is configured to send configuration information of the first message, so that the terminal device receives the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern for sending the first message, a modulation and coding scheme of the first message, and a first RNTI. The modulation and coding scheme of the first message may be specifically as follows: For example, a modulation scheme of the first message is quadrature phase shift keying (English: Quadrature Phase Shift Keying, QPSK for short), and a coding scheme is 1/3 coding; or a modulation scheme of the first message is QPSK, and a coding scheme is 1/2 coding. It should be understood that other coding or modulation schemes may also be used, and the present invention is not limited thereto. The first RNTI refers to an RNTI used by the network device to schedule and send the first message.

0080Optionally, in an embodiment of the present invention, the time pattern for sending the first message by the third sending module includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message. The change period T' of the first message is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. A quantity of repetition times for sending the first message represents a number of times the first message is repeatedly sent within one change period T', and for example, may be specifically 2, 4, 6, 8, or the like. The time offset of the first message is, for example, 0 ms, 1 ms, 2 ms, 3 ms, or the like. When the time pattern of the first message does not include the time offset of the first message, the time offset of the first message is a fixed value of, for example, 0 or 1. It should also be understood that the values listed above are merely examples, other possible values of the change period T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0081Optionally, in an embodiment of the present invention, the first message sent by the first sending module further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service in the at least one group service, a logical channel number of each group service, and a second RNTI. The period T for sending the first message by the network device represents frequency at which the first message is used to send a message. Specifically, the period T may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. For the change period T' of the first message, the period T' is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. The logical channel number of each group service that is sent by the network device is used to represent a logical channel used by the group service. The second RNTI refers to an RNTI used to schedule the group service sent by the network device. It should be understood that the second RNTI may refer to one RNTI used to schedule multiple group services, or may refer to different RNTIs used to schedule multiple group services. That is, each group service has a corresponding RNTI, and each RNTI may correspond to one or more group services, and the present invention is not limited thereto. It should also be understood that the values listed above are merely examples, other possible values of the period T or T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0082Optionally, in an embodiment of the present invention, the first sending module is further configured to: send indication information indicating that the first message is changed to the terminal device, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device. The change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the first downlink control information may be specifically a label value, whose length may be 4 bits, 5 bits, or the like. The downlink control information may be in a format such as 1/1A/1C. Further, the terminal device compares a stored label value with the label value in the change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the first downlink control information. If they are different, it is considered that the first message is changed. It should be understood that the length values of the foregoing representation value are merely examples, and the present invention is not limited thereto.

0083Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, when the network device sends the first message for a quantity of times that equals to the repetition coefficient in one change period T', different redundancy versions may be used each time the first message is sent. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0084Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, the first message is sent in N consecutive subframes starting from a subframe corresponding to each first message scheduling moment. The first messages sent in the subframes may be the same, or different redundancy versions may be used. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0085Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0086<figref idref="f0001 f0002 f0003 f0004">FIG. 1 to FIG. 4</figref> describes in detail the network device and the terminal device. A schematic flowchart of a group communication method according to an embodiment of the present invention is described below with reference to <figref idref="f0005">FIG. 5 and FIG. 6</figref>.

0087<figref idref="f0005">FIG. 5</figref> is a schematic flowchart of a group communication method according to an embodiment of the present invention. Procedures in the method 500 may be separately executed and implemented by corresponding parts of the terminal device 100 or the terminal device 200 according to the embodiments of the present invention. For brevity, details are not described herein again. As shown in <figref idref="f0005">FIG. 5</figref>, the method 500 includes the following steps: <ul id="ul0002" list-style="none" compact="compact"><li>S510. A terminal device receives a first message sent by a network device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service.</li><li>S520. The terminal device receives, according to the first message, a first group service corresponding to a first group service identifier of the terminal device.</li></ul>

0088Specifically, the first message sent by the network device may include a group service identifier list. The group service identifier list includes a group service identifier of at least one group service to be sent by the network device. The group service identifier list may include one or more group service identifiers, and one group service identifier corresponds to one group service. It should be understood that the first message may be an independent broadcast message, or may be carried in a form of specific information in another broadcast message. Specifically, the first message may be a multicast control channel (English: Multicast Control Channel, MCCH for short) message or a multicast configuration message, and the present invention is not limited thereto. Specifically, the group service identifier list may be a temporary mobile group identity (English: Temporary Mobile Group Identity, TMGI for short) list including a TMGI corresponding to the at least one group service, and the present invention is not limited thereto. The first group service identifier of the terminal device 100 refers to a group service identifier of interest to or a group service identifier subscribed to by the terminal device 100. Specifically, the terminal device 100 obtains, from a user service description (English: user service description, USD for short), the group service identifier of interest or the subscribed group service identifier.

0089In step S520, the terminal device distinguishes and identifies, according to a group service identifier in the first message, a group service needing to be received. In this way, the terminal device receives a group service intended to be received.

0090Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0091Optionally, in an embodiment of the present invention, before step S510, the terminal device receives configuration information of the first message, so as to receive the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern that is used by the network device to send the first message, a modulation and coding scheme of the first message, and a first RNTI. The modulation and coding scheme of the first message may be specifically as follows: For example, a modulation scheme of the first message is quadrature phase shift keying (English: Quadrature Phase Shift Keying, QPSK for short), and a coding scheme is 1/3 coding; or a modulation scheme of the first message is QPSK, and a coding scheme is 1/2 coding. It should be understood that other coding or modulation schemes may also be used, and the present invention is not limited thereto. The first RNTI refers to an RNTI used by the network device to schedule and send the first message.

0092Optionally, in an embodiment of the present invention, the time pattern that is used by the network device to send the first message includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message. The change period T' of the first message is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. A quantity of repetition times for sending the first message represents a number of times the first message is repeatedly sent within one change period T', and for example, may be specifically 2, 4, 6, 8, or the like. The time offset of the first message is, for example, 0 ms, 1 ms, 2 ms, 3 ms, or the like. When the time pattern of the first message does not include the time offset of the first message, the time offset of the first message is a fixed value of, for example, 0 or 1. It should also be understood that the values listed above are merely examples, other possible values of the change period T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0093Optionally, in an embodiment of the present invention, the receiving, by the terminal device, configuration information of the first message, so as to receive the first message according to the configuration information of the first message includes: when the configuration information includes the first RNTI, receiving, by the terminal device, first downlink control information according to the first RNTI; or when the configuration information does not include the first RNTI, receiving, by the terminal device, first downlink control information according to a first default RNTI. Specifically, if the configuration information includes the first RNTI, the terminal device parses the first downlink control information according to an RNTI corresponding to the first group service in the first RNTI, so as to receive the first message according to the first downlink control information. If the first message does not include the first RNTI, the terminal device receives the first downlink control information according to the first default RNTI. The first default RNTI is a default RNTI used by the network device to schedule and send the first message. For example, the first default RNTI may be FFF4, FFFC, or the like, and the present invention is not limited thereto.

0094Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0095Optionally, in an embodiment of the present invention, in step S520, when the at least one group service identifier sent by the network device includes the first group service identifier of the terminal device, the second receiving module of the terminal device is configured to receive the first group service according to the first message received by the first receiving module.

0096It should be understood that when the group service identifier list sent by the network device does not include a group service identifier of the terminal device, the terminal device does not receive group service data sent by the network device, and only when the group service identifier list sent by the network device includes a group service identifier of the terminal device, the terminal device receives group service data that is sent by the network device and that corresponds to the group service identifier of the terminal device. For example, when group services to be sent by the network device are group service A, group service B, and group service C, the group service identifier list includes three group service identifiers A, B, and C. Three group service identifiers A, B, and D may be marked in advance for the terminal device according to a requirement of the terminal device. In this case, the terminal device receives only service A and service B that are sent by a network side device, and cannot receive service C.

0097Optionally, in an embodiment of the present invention, the first message further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second RNTI. The period T for sending the first message by the network device represents frequency at which the first message is used to send a message. Specifically, the period T may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. For the change period T' of the first message, the period T' is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. The logical channel number of each group service that is sent by the network device is used to represent a logical channel used by the group service. The logical channel number may be represented by 12 bits, for example, 000000000001, or by 5 bits, for example, 00001, or by any bit quantity ranging from 6 to 13. The bit quantity used may be a length preset by a network, or a length indicated by the first message. The second RNTI refers to an RNTI used to schedule the group service sent by the network device. It should be understood that the second RNTI may refer to one RNTI used to schedule multiple group services, or may refer to different RNTIs used to schedule multiple group services. That is, each group service has a corresponding RNTI, and each RNTI may correspond to one or more group services, and the present invention is not limited thereto. It should also be understood that the values listed above are merely examples, other possible values of the period T or T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0098Optionally, in an embodiment of the present invention, in step S520, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the second RNTI, receiving, by the terminal device, second downlink control information according to the second RNTI; or when the first message does not include the second RNTI, receiving, by the terminal device, second downlink control information according to a second default RNTI. Specifically, if the terminal device needs to receive the first group service corresponding to the first group service identifier when the first message includes the second RNTI, the terminal device parses the second downlink control information according to an RNTI corresponding to the first group service in the second RNTI, so as to receive the first group service according to the second downlink control information. If the first message does not include the second RNTI, the terminal device receives the second downlink control information according to the second default RNTI. The second default RNTI is a default RNTI used to schedule the group service sent by the network device. For example, the second default RNTI may be FFF4, FFFC, or the like, and the present invention is not limited thereto.

0099Specifically, the receiving second downlink control information according to the second RNTI or a second default RNTI is: parsing, at a scheduling time corresponding to the first group service, the second downlink control information that is scrambled with the RNTI of the first group service. The scheduling time of the first group service is a moment that is obtained by performing a modulo operation on the period T by using a sum of a system frame number* 10 and a subframe index of the first group service and that is equal to the time offset corresponding to the first group service.

0100Optionally, in an embodiment of the present invention, in step S520, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: receiving, by the terminal device, a MAC PDU according to the second downlink control information; and when the first message includes the logical channel number of each group service, receiving, by the terminal device according to a logical channel number of the first group service in the logical channel number of each group service, a MAC SDU sent by the network device; or when the first message does not include the logical channel number of each group service, receiving, by the terminal device, a MAC SDU of the first group service according to the first group service identifier.

0101Specifically, for example, when the first message received by the terminal device includes logical channel numbers A, B, and C of group service A, group service B, and group service C that are sent by the network device, a corresponding channel A can be found by using the channel number A corresponding to group service A, the channel number B corresponding to group service B and channel C corresponding to group service C, and a MAC SDU received by the second receiving module is obtained. In this case, if the first message does not include the logical channel numbers, group services A, B, and C all obtain, according to their group service identifiers and by using a channel allocated to an entire group service, a MAC SDU that corresponds to the group service and that is received by the second receiving module.

0102In an embodiment of the present invention, optionally, in step S520, the MAC PDU carries a MAC CE, to indicate that the first group service ends. The MAC PDU including the MAC CE indicating that the service ends may be sent once, or may be repeatedly sent multiple times, for example, three times or five times, so as to improve receiving reliability of the terminal device. A specific implementation manner may be that the MAC CE includes a group service identifier or a logical channel number of a group service sent by the terminal device, and when the terminal device receives a MAC CE including a particular group service identifier or logical channel number, it is considered that the service ends. Alternatively, a specific implementation manner may be that when the MAC CE does not include a group service identifier or a logical channel number corresponding to a group service sent by the terminal device, it is considered that all group services included in the MAC PDU that includes the MAC CE indicating that the service ends end. It should be understood that the numerals mentioned in this embodiment of the present invention are merely examples, and the present invention is not limited thereto.

0103Optionally, in an embodiment of the present invention, the terminal device determines, according to change indication information, that the first message is changed. The change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in SIB1; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the terminal device receives the first downlink control information. The change indication message of the first message that is carried in the SIB 1 message or the indication information that indicates that the first message is changed and that is carried in the first downlink control information may be specifically a label value, whose length may be 4 bits, 5 bits, or the like. The downlink control information may be in a format such as 1/1A/1C. Further, the terminal device compares a stored label value with the label value in the change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the downlink control information of the first message. If they are different, it is considered that the first message is changed. It should be understood that the length values of the foregoing representation value are merely examples, and the present invention is not limited thereto.

0104Optionally, in an embodiment of the present invention, the receiving, by a terminal device, a first message sent by a network device includes: if the terminal device does not store the first message, receiving the first message at a moment at which the network device sends multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receiving a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message. If the terminal device does not store the first message, the terminal device needs to attempt to receive the first message at each first message sending moment, until one first message is correctly received. The terminal device may obtain the first message sending moment by using an SIB1 message, or obtain the first message sending moment from the configuration information of the first message scheduled by the downlink control information, so as to attempt to receive the first message at the first message sending moment. If the terminal device already stores the first message, when determining that the first message is changed, the terminal device needs to start to receive a changed first message after the change period T' has elapsed, so as to receive the first group service according to the changed first message.

0105Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, when the network device sends the first message for a quantity of times that equals to the repetition coefficient in one change period T', different redundancy versions may be used each time the first message is sent. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0106Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, the first message is sent in N consecutive subframes starting from a subframe corresponding to each first message scheduling moment. The first messages sent in the subframes may be the same, or different redundancy versions may be used. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0107Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0108<figref idref="f0005">FIG. 6</figref> is a schematic flowchart of a group communication method according to another embodiment of the present invention. Procedures in the method 600 may be separately executed and implemented by corresponding parts of the terminal device 300 or the terminal device 400 according to the embodiments of the present invention. For brevity, details are not described herein again. As shown in <figref idref="f0005">FIG. 6</figref>, the method 600 includes the following steps: <ul id="ul0003" list-style="none" compact="compact"><li>S610. Send a first message to a terminal device, where the first message includes at least one group service identifier, and one group service identifier corresponds to one group service.</li><li>S620. Send a group service corresponding to the at least one group service identifier to the terminal device.</li></ul>

0109Specifically, the first message sent by the network device may include a group service identifier list. The group service identifier list includes a group service identifier of at least one group service to be sent by the network device. The group service identifier list may include one or more group service identifiers, and one group service identifier corresponds to one group service. It should be understood that the first message may be an independent broadcast message, or may be carried in a form of specific information in another broadcast message. Specifically, the first message may be an MCCH message or a group configuration message, and the present invention is not limited thereto. Specifically, the group service identifier list may be a TMGI list including a TMGI corresponding to the at least one group service, and the present invention is not limited thereto. The group service sent by the network device is group services corresponding to one or more group service identifiers included in the group service identifier list. One group service identifier corresponds to one group service.

0110Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0111Optionally, in an embodiment of the present invention, before step S610, configuration information of the first message is sent, so that the terminal device receives the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern for sending the first message, a modulation and coding scheme of the first message, and a first RNTI. The modulation and coding scheme of the first message may be specifically as follows: For example, a modulation scheme of the first message is quadrature phase shift keying (English: Quadrature Phase Shift Keying, QPSK for short), and a coding scheme is 1/3 coding; or a modulation scheme of the first message is QPSK, and a coding scheme is 1/2 coding. It should be understood that other coding or modulation schemes may also be used, and the present invention is not limited thereto. The first RNTI refers to an RNTI used by the network device to schedule and send the first message.

0112Optionally, in an embodiment of the present invention, the time pattern for sending the first message includes at least one of the following information: a change period of the first message, a repetition coefficient of the first message, and a time offset of the first message. The change period T' of the first message is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. A quantity of repetition times for sending the first message represents a number of times the first message is repeatedly sent within one change period T', and for example, may be specifically 2, 4, 6, 8, or the like. The time offset of the first message is, for example, 0 ms, 1 ms, 2 ms, 3 ms, or the like. When the time pattern of the first message does not include the time offset of the first message, the time offset of the first message is a fixed value of, for example, 0 or 1. It should also be understood that the values listed above are merely examples, other possible values of the change period T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0113Optionally, in an embodiment of the present invention, the first message further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second RNTI. The period T for sending the first message by the network device represents frequency at which the first message is used to send a message. Specifically, the period T may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. For the change period T' of the first message, the period T' is used to instruct the terminal device to receive, after determining that the first message is changed, a changed first message sent by the network device, after the change period T' has elapsed. Specifically, the period T' may be 20 ms, 50 ms, 100 ms, 500 ms, or the like. The logical channel number of each group service that is sent by the network device is used to represent a logical channel used by the group service. The second RNTI refers to an RNTI used to schedule the group service sent by the network device. It should be understood that the second RNTI may refer to one RNTI used to schedule multiple group services, or may refer to different RNTIs used to schedule multiple group services. That is, each group service has a corresponding RNTI, and each RNTI may correspond to one or more group services, and the present invention is not limited thereto. It should also be understood that the values listed above are merely examples, other possible values of the period T or T' all fall within the protection scope of the present invention, and the present invention is not limited thereto.

0114Optionally, in an embodiment of the present invention, S610 further includes: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending second downlink control information carrying the indication information to the terminal device. The change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the second downlink control information may be specifically a label value, whose length may be 4 bits, 5 bits, or the like. The downlink control information may be in a format such as 1/1A/1C. Further, the terminal device compares a stored label value with the label value in the change indication message of the first message that is carried in the SIB1 message or the indication information that indicates that the first message is changed and that is carried in the downlink control information of the first message. If they are different, it is considered that the first message is changed. It should be understood that the length values of the foregoing representation value are merely examples, and the present invention is not limited thereto.

0115Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, when the network device sends the first message for a quantity of times that equals to the repetition coefficient in one change period T', different redundancy versions may be used each time the first message is sent. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0116Optionally, in an embodiment of the present invention, to improve reliability of user equipment in receiving the first message, the first message is sent in N consecutive subframes starting from a subframe corresponding to each first message scheduling moment. The first messages sent in the subframes may be the same, or different redundancy versions may be used. In this way, the terminal device can correctly receive the first message by combining multiple first messages, thereby improving reliability of a user in receiving the first message.

0117Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0118<figref idref="f0006">FIG. 7</figref> is a schematic flowchart of a group communication method according to still another embodiment of the present invention. As shown in <figref idref="f0006">FIG. 7</figref>, the method includes the following steps: <ul id="ul0004" list-style="none" compact="compact"><li>S701. A network device sends a first message.</li><li>S702. The terminal device receives the first message.</li><li>S703. The network device sends group service data.</li><li>S704. The terminal device receives the group service data according to the first message.</li></ul>

0119In step S701, the first message sent by the network device includes at least one group service identifier, and one group service identifier corresponds to one group service.

0120In step S703, the network device sends a group service corresponding to the at least one group service identifier to the terminal device.

0121In step S704, the terminal device receives, according to the first message, a first group service corresponding to a first group service identifier of the terminal device.

0122Optionally, in step S704, when the at least one group service identifier sent by the network device includes the first group service identifier of the terminal device, the second receiving module of the terminal device is configured to receive the first group service according to the first message received by the first receiving module.

0123Optionally, in step S701, the first message further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second RNTI.

0124Optionally, in step S704, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the second RNTI, receiving, by the terminal device, second downlink control information according to the second RNTI; or when the first message does not include the second RNTI, receiving, by the terminal device, second downlink control information according to a second default RNTI.

0125Optionally, in step S704, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the logical channel number of each group service corresponding to the at least one group service identifier, receiving, by the terminal device, a MAC PDU according to the second downlink control information; and obtaining, by the terminal device, a MAC SDU of the first group service according to a logical channel number of the first group service in the logical channel number of each group service.

0126Optionally, in step S704, the MAC PDU carries a MAC CE, to indicate that the first group service ends.

0127Optionally, the terminal device determines, according to change indication information, that the first message is changed. The change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in SIB1; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the terminal device receives the first downlink control information.

0128Optionally, in an embodiment of the present invention, the network device sends, to the terminal device, indication information indicating that the first message is changed, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device.

0129Optionally, in an embodiment of the present invention, the receiving, by a terminal device, a first message sent by a network device includes: if the terminal device does not store the first message, receiving the first message at a moment at which the network device sends multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receiving a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message.

0130Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0131<figref idref="f0007">FIG. 8</figref> is a schematic flowchart of a group communication method according to still another embodiment of the present invention. As shown in <figref idref="f0006">FIG. 7</figref>, the method includes the following steps: <ul id="ul0005" list-style="none" compact="compact"><li>S801. A network device sends configuration information of a first message.</li><li>S802. A terminal device receives the configuration information of the first message.</li><li>S803. The network device sends the first message.</li><li>S804. The terminal device receives the first message according to the configuration information of the first message.</li><li>S805. The network device sends group service data.</li><li>S806. The terminal device receives the group service data according to the first message.</li></ul>

0132In step S801, the network device sends the configuration information of the first message, to instruct the terminal device to receive the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern that is used by the network device to send the first message, a modulation and coding scheme of the first message, and a first RNTI.

0133Optionally, in step S801, the time pattern that is used by the network device to send the first message includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0134Optionally, in step S803, the first message sent by the network device further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service corresponding to at least one group service identifier, a logical channel number of each group service, and a second RNTI.

0135Optionally, in step S804, the receiving, by the terminal device, configuration information of the first message, so as to receive the first message according to the configuration information of the first message includes: when the configuration information includes the first RNTI, receiving, by the terminal device, first downlink control information according to the first RNTI; or when the configuration information does not include the first RNTI, receiving, by the terminal device, first downlink control information according to a first default RNTI.

0136In step S805, the network device sends a group service corresponding to the at least one group service identifier to the terminal device.

0137Optionally, in step S806, when the at least one group service identifier sent by the network device includes a first group service identifier of the terminal device, the second receiving module of the terminal device is configured to receive a first group service according to the first message received by the first receiving module.

0138Optionally, the first message sent by the network device further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second RNTI.

0139Optionally, in step S806, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the second RNTI, receiving, by the terminal device, second downlink control information according to the second RNTI; or when the first message does not include the second RNTI, receiving, by the terminal device, second downlink control information according to a second default RNTI.

0140Optionally, in step S806, the receiving, by the terminal device according to the first message, a first group service corresponding to a first group service identifier of the terminal device includes: when the first message includes the logical channel number of each group service corresponding to the at least one group service identifier, receiving, by the terminal device, a MAC PDU according to the second downlink control information; and obtaining, by the terminal device, a MAC SDU of the first group service according to a logical channel number of the first group service in the logical channel number of each group service.

0141Optionally, in step S806, the MAC PDU carries a MAC CE, to indicate that the first group service ends.

0142Optionally, the terminal device determines, according to change indication information, that the first message is changed. The change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in SIB1; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the terminal device receives the first downlink control information.

0143Optionally, in an embodiment of the present invention, the network device sends, to the terminal device, indication information indicating that the first message is changed, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device.

0144Optionally, Optionally, in an embodiment of the present invention, the receiving, by a terminal device, a first message sent by a network device includes: if the terminal device does not store the first message, receiving the first message at a moment at which the network device sends multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receiving a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message.

0145Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0146<figref idref="f0008">FIG. 9</figref> is a schematic block diagram of a terminal device according to another embodiment of the present invention. As shown in FIG. 900, the apparatus 900 includes a processor 910, a memory 920, a bus system 930, and a receiver 940. The processor 910, the memory 920, and the receiver 940 are connected by the bus 930. The memory is configured to store an instruction. The processor 910 is configured to execute the instruction stored in the memory 920, and control the receiver 840 to receive information. The receiver 940 may be configured to receive a first message sent by a network device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service. The receiver 940 is further configured to receive, according to the first message, a first group service corresponding to a first group service identifier of the terminal device.

0147Optionally, in an embodiment of the present invention, the receiver 940 is configured to receive configuration information of the first message, so as to receive the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern that is used by the network device to send the first message, a modulation and coding scheme of the first message, and a first RNTI.

0148Optionally, in an embodiment of the present invention, the time pattern, received by the receiver 940, for sending the first message includes at least one of the following information: a change period of the first message, a repetition coefficient for sending the first message, and a time offset of the first message.

0149Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: when the configuration information includes the first RNTI, receive first downlink control information according to the first RNTI; or when the configuration information does not include the first RNTI, receive first downlink control information according to a first default RNTI.

0150Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: when the at least one group service identifier includes the first group service identifier of the terminal device, the terminal device receives the first group service according to the first message.

0151Optionally, in an embodiment of the present invention, the first message received by the receiver 940 further includes at least one of the following information: a period for sending the first message by the network device, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a logical channel number of each group service, and a second RNTI.

0152Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: when the first message includes the second RNTI, the terminal device receives second downlink control information according to the second RNTI; or when the first message does not include the second RNTI, the terminal device receives downlink control information of each group service according to a second default RNTI.

0153Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: when the first message includes the second RNTI, receive second downlink control information according to the second RNTI, so as to receive the first group service according to the second downlink control information; or when the first message does not include the second RNTI, the terminal device receives second downlink control information according to a second default RNTI, so as to receive the first group service according to the second downlink control information.

0154Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: receive a MAC PDU according to the second downlink control information; and when the first message includes the logical channel number of each group service, the terminal device receives, according to a logical channel number of the first group service in the logical channel number of each group service, a MAC SDU of the first group service; or when the first message does not include the logical channel number of each group service, the terminal device receives, according to the first group service identifier, a MAC SDU of the first group service.

0155Optionally, in an embodiment of the present invention, the processor 910 is configured to determine, according to change indication information, that the first message is changed. The change indication information includes: indication information that indicates that the first message is changed and that is carried in a paging message; or indication information that indicates that the first message is changed and that is carried in an SIB1 message; or indication information that indicates that the first message is changed and that is carried in the first downlink control information, when the terminal device receives the first downlink control information.

0156Optionally, in an embodiment of the present invention, the receiver 940 is further configured to: if the terminal device does not store the first message, receive the first message at a moment at which the network device sends multicast control information; and if the terminal device already stores the multicast control information and determines that the first message is changed, receive a changed first message at a moment at which the network device sends the changed first message, so as to receive a changed first group service according to the changed first message.

0157Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0158<figref idref="f0008">FIG. 10</figref> is a schematic block diagram of a network device according to another embodiment of the present invention. As shown in FIG. 1000, the apparatus 1000 includes a processor 1100, a memory 1200, a bus system 1300, and a transmitter 1400. The processor 1100, the memory 1200, and the transmitter 1400 are connected by the bus 1300. The memory is configured to store an instruction. The processor 1100 is configured to execute the instruction stored in the memory 1200, and control the transmitter 1400 to receive information. The transmitter 1400 may be configured to receive a first message sent by a network device. The first message includes at least one group service identifier, and one group service identifier corresponds to one group service. The transmitter 1400 is further configured to send a group service corresponding to the at least one group service identifier to the terminal device.

0159Optionally, in an embodiment of the present invention, the transmitter 1400 is configured to send configuration information of the first message, so that the terminal device receives the first message according to the configuration information of the first message. The configuration information of the first message includes at least one of the following information: a time pattern for sending the first message, a first RNTI manner, and a modulation and coding scheme of the first message.

0160Optionally, in an embodiment of the present invention, the time pattern used by the transmitter 1400 to send the first message includes at least one of the following information: a change period of the first message, a repetition coefficient of the first message, and a time offset of the first message.

0161Optionally, in an embodiment of the present invention, the first message sent by the transmitter 1400 further includes at least one of the following information: a period for sending the first message, a change period of the first message, a time offset of each group service corresponding to the at least one group service identifier, a second RNTI, and a logical channel number of each group service.

0162Optionally, in an embodiment of the present invention, the transmitter 1400 is configured to send indication information indicating that the first message is changed to the terminal device, including: sending a paging message carrying the indication information to the terminal device; or sending an SIB1 message carrying the indication information to the terminal device; or sending first downlink control information carrying the indication information to the terminal device.

0163Based on the foregoing technical solution, a terminal device receives a first message that is sent by a network device and that includes a group service identifier of each group service sent by the network device, so that the terminal device can receive, according to the received first message, a group service sent by the network device. Therefore, implementations of the present invention provide a method for implementing group communication, a terminal device, and a network device. In this way, not only point-to-multipoint group communication in a single cell can be implemented, but also one group service can be sent by using only one share of resources to all terminal devices that need to receive the group service, thereby reducing a waste of radio resources. In addition, receiving configuration of each group service can further be modified by using a unified configuration message, thereby implementing dynamic, flexible, and efficient group service configuration and transmission.

0164It should be noted that in all of the foregoing embodiments of the present invention, the processing module may be implemented by at least one processor. The processor may be a central processing unit (Central Processing Unit, CPU), or may be another general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or another programmable logic device, independent gate or transistor logic device, independent hardware component, or the like. The sending module may be implemented by a transmitter, or may be implemented by a transceiver. In addition, in the foregoing embodiments of the present invention, the network device and the user equipment may further include parts such as a receiver and a memory. The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A part of the memory may further include a non-volatile random access memory. For example, the memory may further store device type information. The processor invokes instruction code of the memory to control other modules of the network device and the user equipment in the embodiments of the present invention to perform the foregoing operations.

0165It should be understood that "an embodiment" or "an embodiment" mentioned in the whole specification does not mean that particular features, structures, or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in an embodiment" or "in an embodiment" appearing throughout the specification does not refer to a same embodiment. In addition, these particular features, structures, or characteristics may be combined in one or more embodiments by using any appropriate manner.

0166It should be understood that sequence numbers of the foregoing processes do not mean execution sequences in various embodiments of the present invention. The execution sequences of the processes should be determined according to functions and internal logic of the processes, and should not be construed as any limitation on the implementation processes of the embodiments of the present invention.

0167In addition, the terms "system" and "network" may be used interchangeably in this specification. The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, the character "/" in this specification generally indicates an "or" relationship between the associated objects.

0168It should be understood that in the embodiments of this application, "B corresponding to A" indicates that B is associated with A, and B may be determined according to A. However, it should further be understood that determining A according to B does not mean that B is determined according to A only; that is, B may also be determined according to A and/or other information.

0169A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof. To clearly describe the interchangeability between the hardware and the software, the foregoing has generally described compositions and steps of each example according to functions. Whether the functions are performed by hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the present invention.

0170It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, for a detailed working process of the foregoing system, apparatus, and unit, reference may be made to a corresponding process in the foregoing method embodiments, and details are not described herein again.

0171In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the unit division is merely logical function division and may be other division in actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

0172The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

0173In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit.

0174When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of the present invention essentially, or the part contributing to the prior art, or some of the technical solutions may be implemented in a form of a software product. The software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to perform all or some of the steps of the methods described in the embodiments of the present invention. The foregoing storage medium includes: any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, or an optical disc.

0175The foregoing descriptions are merely specific implementation manners of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.