CN106358317B - A kind of method and system for realizing LTE air interface multicast - Google Patents

Abstract

The invention discloses a method and a system for realizing LTE air interface multicast. In the method, a 4G core network establishes an ERAB for carrying multicast data for user equipment with multicast requirements; when the user equipment joins multicast, the 4G The core network sends an ERAB modification request to the LTE base station; the LTE base station generates a semi-persistently scheduled wireless network temporary identifier according to the address mapping information of the ERAB modification request, and instructs the user equipment to establish semi-persistent scheduling; the user equipment receives the semi-persistently scheduled radio network. Network temporary identifier, perform RRC connection reconfiguration to establish semi-persistent scheduling, and feed back a message of completion of semi-persistent scheduling establishment to the LTE base station, and then join the multicast. It can be seen from this that all user equipments supporting LTE can join the multicast, the scheduling is flexible and simple, and the applicable scope of the LTE air interface multicast is improved.

Description

A method and system for realizing LTE air interface multicast

technical field

The present invention relates to the field of communications, in particular to a method and system for implementing LTE air interface multicast.

Background technique

The broadband trunking communication standard "Broadband trunking communication based on LTE technology (B-TrunC) system interface technical requirements (first stage) air interface" uses G-RNTI to realize air interface multicast, but this standard needs to modify the terminal protocol stack, only dedicated Only mobile phones can support this protocol, so that some existing mobile terminals cannot perform multicast.

It can be seen that the existing technology still needs to be improved and improved.

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a method and system for implementing LTE air interface multicast, which is flexible and simple in scheduling, and user equipment that supports LTE can support multicast.

In order to achieve the above object, the present invention has adopted the following technical solutions:

A method for implementing LTE air interface multicast, comprising the following steps:

A. The 4G core network establishes an ERAB for carrying multicast data for user equipment with multicast requirements;

B1. When the user equipment joins the multicast, the 4G core network sends an ERAB modification request to the LTE base station to complete the mapping of the IP multicast address to the C-RNTI;

B2. The LTE base station generates a semi-persistent scheduling wireless network temporary identifier according to the address mapping information of the ERAB modification request, and instructs the user equipment to establish semi-persistent scheduling;

B3. The user equipment receives the semi-persistent scheduling wireless network temporary identifier, performs RRC connection reconfiguration to establish the semi-persistent scheduling, and feeds back a message that the semi-persistent scheduling is established to the LTE base station;

B4. The LTE base station notifies the 4G core network ERAB that the modification is completed, and the user equipment joins the multicast.

In the described method for implementing LTE air interface multicast, the step A specifically includes the steps:

A1. The 4G core network sends an ERAB establishment request to the LTE base station, requesting the establishment of an ERAB;

A2. The LTE base station sends an M-DRB addition instruction to the user equipment to instruct the user equipment to establish an M-DRB;

A3. After receiving the M-DRB addition instruction, the user equipment establishes an M-DRB through RRC connection reconfiguration, and feeds back a message of the completion of the M-DRB establishment to the LTE base station;

A4. The LTE base station uses the ERAB establishment response to notify the 4G core network that the M-DRB establishment is complete.

In the described method for implementing LTE air interface multicast, after step B4, the method further includes the following steps:

C1. When the user equipment quits multicast, the 4G core network sends an ERAB modification request to the LTE base station to make the user equipment quit multicast;

C2, the LTE base station sends a semi-persistent scheduling release instruction to the user equipment according to the ERAB modification request;

C3. After receiving the semi-persistent scheduling release instruction, the user equipment releases the semi-persistent scheduling through RRC connection reconfiguration, and no longer uses the semi-persistent scheduling wireless network temporary identifier to receive data, thereby exiting the multicast.

In the described method for implementing LTE air interface multicast, when the LTE base station needs to transmit downlink multicast data, the downlink control information for activating semi-persistent scheduling is used to notify the user equipment to receive data; after data transmission is completed, the deactivating semi-static scheduling is used. The statically scheduled downlink control information informs the user equipment to stop receiving data.

A system for implementing LTE air interface multicast, the system comprising:

The 4G core network is used to establish an ERAB for carrying multicast data for user equipment with multicast requirements; when the user equipment joins multicast, the modified ERAB is sent to the LTE base station to complete the mapping of IP multicast addresses to C-RNTI ERAB modification request;

The LTE base station is used to generate the semi-persistent scheduling wireless network temporary identifier according to the address mapping information of the ERAB modification request, and instruct the user equipment to establish the semi-persistent scheduling;

The user equipment is configured to receive the semi-persistent scheduling wireless network temporary identifier, perform RRC connection reconfiguration to establish the semi-persistent scheduling, and feed back a message that the semi-persistent scheduling establishment is completed to the LTE base station.

In the described system for realizing LTE air interface multicast, when the 4G core network establishes an ERAB for carrying multicast data for user equipment with multicast requirements, an ERAB establishment request is sent to an LTE base station, and an ERAB is required to be established. Described LTE base station is also used for after receiving ERAB establishment request, sends M-DRB increase instruction to user equipment, to instruct user equipment to establish M-DRB; And after user equipment completes M-DRB establishment, uses ERAB to establish response Notifying the 4G core network that the M-DRB establishment is completed; the user equipment is further configured to establish the M-DRB through RRC connection reconfiguration after receiving the M-DRB addition instruction, and feed back a message that the M-DRB establishment is complete to the LTE base station.

In the described system for realizing LTE air interface multicast, the 4G core network is also used to send an ERAB modification request that causes the user equipment to quit multicast to the LTE base station when the user equipment exits the multicast, and requires that the ERAB be modified to make the user equipment. Exit the multicast; the LTE base station is also used to send a semi-persistent scheduling release instruction to the user equipment after receiving the ERAB modification request for the user equipment to exit the multicast; the user equipment is also used to receive the semi-persistent scheduling release After the instruction, the semi-persistent scheduling is released through the RRC connection reconfiguration, and the semi-persistent scheduling wireless network temporary identifier is no longer used to receive data, thereby quitting the multicast.

In the system for implementing LTE air interface multicast, when the LTE base station needs to transmit downlink multicast data, it uses the downlink control information for activating semi-persistent scheduling to notify the user equipment to receive data; The statically scheduled downlink control information informs the user equipment to stop receiving data.

Beneficial effects:

The present invention provides a method and system for implementing LTE air interface multicast. In the method, a 4G core network establishes an ERAB for carrying multicast data for user equipment with multicast requirements; when the user equipment joins multicast, the 4G The core network sends an ERAB modification request to the LTE base station; the LTE base station generates a semi-persistently scheduled wireless network temporary identifier according to the address mapping information of the ERAB modification request, and instructs the user equipment to establish semi-persistent scheduling; the user equipment receives the semi-persistently scheduled radio network. Network temporary identifier, perform RRC connection reconfiguration to establish semi-persistent scheduling, and feed back a message of completion of semi-persistent scheduling establishment to the LTE base station, and then join the multicast. It can be seen from this that all user equipments supporting LTE can join the multicast, the scheduling is flexible and simple, and the applicable scope of the LTE air interface multicast is improved.

Description of drawings

FIG. 1 is a flowchart of a method for implementing LTE air interface multicast provided by the present invention.

FIG. 2 is a schematic flowchart of user equipment joining multicast in the method for implementing LTE air interface multicast provided by the present invention.

FIG. 3 is a schematic flowchart of establishing an M-DRB in the method for implementing LTE air interface multicast provided by the present invention.

FIG. 4 is a schematic flowchart of user equipment exiting multicast in the method for implementing LTE air interface multicast provided by the present invention.

Detailed ways

The present invention provides a method and system for realizing LTE air interface multicast. In order to make the purpose, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

According to 3GPP TS 36.213 7.1, when the user equipment (User Equipment, UE) upper layer is configured with a semi-persistently scheduled radio network temporary identifier (SPS C-RNTI), the UE shall use the SPS C-RNTI to pair the downlink physical control channel (PDCCH) and The corresponding downlink physical shared channel (PDSCH) is decoded; the cyclic redundancy check (CRC) of the PDCCH is scrambled by the SPS C-RNTI. In fact, in the LTE system, the downlink control information (DCI) indicates all necessary information such as the PDSCH physical layer resources and transmission format of the UE in the corresponding subframe. The PDCCH carries the DCI, and the CRC of the PDCCH and the corresponding PDSCH are determined by the corresponding subframes. The RNTI is scrambled, so the present invention considers that the role of the RNTI in the LTE physical layer is equivalent to the role of the MAC address in the Ethernet. Therefore, the RRC (Radio Resource Control) protocol of the present invention configures the same SPS C-RNTI to several UEs, and these UEs form a multicast group, thereby realizing multicast. The RRC protocol (RRC) is responsible for the management of the RRC connection, and according to 3GPP TS 36.331 5.3.1, the management of the M-DRB is implemented through RRC connection reconfiguration.

Multicast is a network technology that allows one or more senders (multicast sources) to send a single data packet to multiple receivers (once, simultaneously). The multicast source sends data packets to a specific multicast group, and only addresses belonging to the multicast group can receive the data packets. For wired networks, there is a set of IP address allocation policies and a mechanism for mapping Layer 3 IP multicast addresses to Layer 2 Ethernet addresses; its management mainly includes joining and exiting multicast. The air interface of LTE is equivalent to Ethernet (Layer 2). To implement multicast, it is only necessary to complete the function of mapping from Layer 3 addresses to Layer 2 addresses, that is, when a terminal joins and exits multicast, the LTE air interface completes the mapping from Layer 3 addresses to Layer 2 addresses (C-RNTI). . At the same time, in the uplink direction, that is, the direction from the terminal to the base station, data transmission is always carried out one-to-one, and there is no need for multicast; multicast is applied to the downlink direction, that is, the direction from the base station to the terminal, that is, multiple terminals use the same physical layer resources to receive downlink groups. broadcast data. The present invention uses a dedicated M-DRB (Multicast Data Radio Bearer) to bear multicast data, and address mapping is realized through RRC management of M-DRB and activation and deactivation of SPS (version static scheduling) by MAC protocol. The MAC completes the function of radio resource scheduling.

Specifically, please refer to FIG. 1, the present invention provides a method for implementing LTE air interface multicast, and the method includes the following steps:

S10. The 4G core network (EPC) establishes an ERAB (Evolved Radio Access Bearer) for carrying multicast data for user equipment with multicast requirements. In this embodiment, the user equipment is a mobile terminal with an LTE function.

S210. When the user equipment joins the multicast, the 4G core network sends the ERAB to the LTE base station (eNodeB) to modify the ERAB (Evolved Radio Access Bearer) to complete the mapping of the IP multicast address to the C-RNTI (Radio Network Temporary Identifier). The modification request requires modification of the ERAB to complete the mapping from the Layer 3 address to the Layer 2 address.

S220. The LTE base station generates a semi-persistent scheduling radio network temporary identifier (SPS C-RNTI) according to the address mapping information of the ERAB modification request, and instructs the user equipment to establish a semi-persistent scheduling (SPS). Specifically, the eNodeB generates the SPS C-RNTI according to the address mapping information of the ERAB modification request, and instructs the UE to establish the SPS through the message RRC connection reconfiguration message, and prepares to receive the multicast data scrambled by the SPS C-RNTI.

S230. The user equipment receives the semi-persistent scheduling wireless network temporary identifier, performs RRC connection reconfiguration to establish semi-persistent scheduling, and feeds back a semi-persistent scheduling (SPS) establishment completion message to the LTE base station.

S240, the LTE base station notifies the 4G core network user equipment that the ERAB modification is completed, and the user equipment joins the multicast.

Referring to FIG. 2 , the steps S210 to S240 are the flow of the user equipment joining the multicast. It can be seen from this that all user equipments supporting LTE can join the multicast, the scheduling is flexible and simple, and the applicable scope of the LTE air interface multicast is improved.

Further, please refer to FIG. 3, the step S10 specifically includes steps:

S110. The 4G core network sends an ERAB establishment request to the LTE base station, requesting to establish an ERAB for carrying multicast data; the ERAB is a data path from the user equipment to the 4G core network through the LTE base station.

S120. The LTE base station sends an M-DRB addition instruction to the user equipment to instruct the user equipment to establish an M-DRB; the M-DRB refers to the data path between the user equipment and the LTE base station, which is equivalent to a section of ERAB.

S130. After receiving the M-DRB addition instruction, the user equipment establishes an M-DRB through RRC connection reconfiguration, and feeds back a message that the M-DRB establishment is completed to the LTE base station;

S140, the LTE base station uses the ERAB establishment response to notify the 4G core network that the establishment of the ERAB for carrying the multicast data is completed.

Further, the present invention also includes the process of exiting the multicast, that is, after the step S240, the following steps are also included:

S310, when the user equipment quits multicast, the 4G core network sends an ERAB modification request to the LTE base station for the user equipment to quit multicast;

S320, the LTE base station sends a semi-persistent scheduling release instruction to the user equipment according to the ERAB modification request;

S330. After receiving the semi-persistent scheduling release instruction, the user equipment releases the semi-persistent scheduling through RRC connection reconfiguration, and no longer uses the semi-persistent scheduling wireless network temporary identifier to receive data, thereby quits multicast, and uses the RRC connection reconfiguration completion notification eNodeB;

S340. The LTE base station sends an ERAB modification response to notify the 4G core network user equipment that the multicast has been withdrawn.

From the perspective of power saving of the mobile terminal, the mobile terminal only needs to receive data when there is data transmission in the downlink direction. For SPS (semi-persistent scheduling), the present invention designs a mechanism for SPS activation and deactivation. According to 3GPP TS 36.2139.2, when SPS transmission is activated, SPS C-RNTI needs to be used to scramble the PDCCH; secondly, the NDI field is set to 0, which are two basic conditions. For further strict verification, other fields in the DCI (Downlink Control Information) need to be checked.

The DCI format is a bit stream, and the content of DCI format 1 is as follows:

Resource allocation type 0 or 1: 1 bit;

Resource block allocation and modulation and coding scheme: 5 bits;

Number of HARQ (Hybrid Automatic Repeat Request) processes: TDD (Time Division Duplex) 4 bits; FDD (Frequency Division Duplex) 3 bits;

New data indication: 1 bit;

Redundancy version: 2 bits;

PUCCH (Physical Uplink Control Channel) transmission power control command: 2 bits;

Downlink allocation index: 2 bits.

The contents of DCI format 1A are as follows:

Centralized and distributed virtual radio resource block allocation flag: 1 bit;

Resource block allocation and modulation and coding scheme: 5 bits;

Number of HARQ processes: TDD 4 bits; FDD 3 bits;

New data indication: 1 bit;

Redundancy version: 2 bits;

PUCCH transmission power control command: 2 bits;

Downlink Allocation Index: 2 bits.

MAC uses DCI format 1 or DCI format 1A of specific content to activate SPS transmission. DCI needs to be specially set as shown in Table 1:

Table 1 DCI for activating SPS.

The MAC uses the content-specific DCI format 1A to deactivate the SPS transmission. The DCI needs to be specially set as follows:

Table 2 DCI for deactivating SPS.

When the LTE base station needs to transmit downlink multicast data, it uses downlink control information (DCI) to activate semi-persistent scheduling to notify the user equipment to receive data; after data transmission is completed, it uses the downlink control information to deactivate semi-persistent scheduling to notify the user. The device stops receiving data. This setting is beneficial to save power.

Based on the method for implementing LTE air interface multicast provided by the above embodiments, the present invention also provides a system for implementing LTE air interface multicast, the system including the above 4G core network, the above LTE base station and the above the user equipment.

The 4G core network is used to establish an ERAB for carrying multicast data for user equipment with multicast requirements; when the user equipment joins multicast, the LTE base station sends the modified ERAB to complete the IP multicast address to the C-RNTI (Wireless Network Temporary Identifier) mapped ERAB modification request.

The LTE base station is configured to generate a semi-persistent scheduling radio network temporary identifier (SPS C-RNTI) according to the address mapping information of the ERAB modification request, and instruct the user equipment to establish a semi-persistent scheduling (SPS).

The user equipment is configured to receive the semi-persistent scheduling wireless network temporary identifier, perform RRC connection reconfiguration to establish semi-persistent scheduling, and feed back a semi-persistent scheduling (SPS) establishment completion message to the LTE base station.

When the 4G core network establishes an ERAB for carrying multicast data for user equipment with multicast requirements, it sends an ERAB establishment request to the LTE base station, requesting to establish an ERAB. The LTE base station is also used to send an M-DRB addition instruction to the user equipment after receiving the ERAB establishment request to instruct the user equipment to establish the M-DRB; and after the user equipment completes the M-DRB establishment, use the ERAB establishment response notification The establishment of the 4G core network M-DRB is completed. The user equipment is further configured to establish an M-DRB through RRC connection reconfiguration after receiving the M-DRB addition instruction, and feed back a message that the M-DRB establishment is completed to the LTE base station.

The 4G core network is further configured to send an ERAB modification request for withdrawing the user equipment from the multicast to the LTE base station when the user equipment withdraws from the multicast, requesting to modify the ERAB to make the user equipment withdraw from the multicast. The LTE base station is further configured to send a semi-persistent scheduling release instruction to the user equipment after receiving the ERAB modification request for withdrawing the user equipment from multicast. The user equipment is further configured to release the semi-persistent scheduling through RRC connection reconfiguration after receiving the semi-persistent scheduling release instruction, and no longer use the semi-persistent scheduling wireless network temporary identifier to receive data, thereby exiting the multicast.

When the LTE base station needs to transmit downlink multicast data, it uses downlink control information (DCI) to activate semi-persistent scheduling to notify the user equipment to receive data; after data transmission is completed, it uses the downlink control information to deactivate semi-persistent scheduling to notify the user. The device stops receiving data.

It can be seen that, in the system for realizing LTE air interface multicast provided by the present invention, user equipment supporting LTE can join the multicast, the scheduling is flexible and simple, and the applicable scope of LTE air interface multicast is improved. Since the features and principles of the system correspond to the method embodiments, they will not be repeated here.

It can be understood that for those of ordinary skill in the art, equivalent replacements or changes can be made according to the technical solutions of the present invention and the inventive concept thereof, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (6)

1. a kind of method for realizing LTE air interface multicast, which comprises the steps of:

A, 4G core net is to have the user equipment of multicast requirement to establish the ERAB for being used for bear multicast data；

The step A specifically includes step:

A1,4G core net send ERAB and establish request to LTE base station, it is desirable that establish ERAB；

A2, LTE base station send M-DRB and increase instruction to user equipment, to indicate that user equipment establishes M-DRB；

After A3, user equipment receive the M-DRB increase instruction, M-DRB is established by RRC connection reconfiguration, and feed back M-DRB The message completed is established to LTE base station；

A4, LTE base station are established response notice 4G core net M-DRB foundation using ERAB and are completed；

B1, user equipment addition group sowing time, 4G core net send modification ERAB to LTE base station to complete IP multicast address to C- The ERAB of the mapping of RNTI modifies request；

B2, LTE base station generate semi-persistent scheduling wireless network according to the address mapping information of ERAB modification request and temporarily mark Know symbol, and indicates that user equipment establishes semi-persistent scheduling;

B3, user equipment receive the semi-persistent scheduling radio network temporary identifier, and it is quiet to establish half to carry out RRC connection reconfiguration State scheduling, and feed back semi-persistent scheduling and establish the message completed to LTE base station；

B4, LTE base station notice 4G core net ERAB modification are completed, and multicast is added in user equipment.

2. the method according to claim 1 for realizing LTE air interface multicast, which is characterized in that after the step B4, Further include following steps:

C1, user equipment exit a group sowing time, and 4G core net sends the ERAB modification request for making user equipment exit multicast and gives LTE base It stands；

C2, LTE base station are modified according to the ERAB and are requested, and are sent semi-persistent scheduling and are released order to user equipment；

C3, user equipment receive after semi-persistent scheduling releases order, and discharge semi-persistent scheduling by RRC connection reconfiguration, no longer Data are received using semi-persistent scheduling radio network temporary identifier, to exit multicast.

3. the method according to claim 1 for realizing LTE air interface multicast, which is characterized in that when LTE base station needs to pass When defeated downlink multicast data, data are received using the down link control information notifying user equipment of activation semi-persistent scheduling；It is complete After transmitting at data, stop receiving data using the down link control information notifying user equipment for deactivating semi-persistent scheduling.

4. a kind of system for realizing LTE air interface multicast, which is characterized in that the system comprises:

4G core net, for for have the user equipment of multicast requirement establish be used for bear multicast data ERAB；In user equipment Addition group sowing time sends modification ERAB to LTE base station to complete the ERAB modification request of the mapping of IP multicast address to C-RNTI；

The 4G core net is when having the user equipment of multicast requirement to establish the ERAB for being used for bear multicast data, to send ERAB and build It is vertical to request to LTE base station, it is desirable that establish ERAB；The LTE base station is also used to after receiving ERAB and establishing request, sends M- DRB increases instruction to user equipment, to indicate that user equipment establishes M-DRB；And after user equipment completes M-DRB foundation, make Response notice 4G core net M-DRB, which is established, with ERAB establishes completion；The user equipment is also used to receiving the M-DRB increasing After adding instruction, M-DRB is established by RRC connection reconfiguration, and feeds back M-DRB and establishes the message completed to LTE base station；

LTE base station, for generating semi-persistent scheduling radio network temporary identifier according to the address mapping information of ERAB modification request Symbol, and indicate that user equipment establishes semi-persistent scheduling；

User equipment carries out RRC connection reconfiguration for receiving the semi-persistent scheduling radio network temporary identifier to establish half Static scheduling, and feed back semi-persistent scheduling and establish the message completed to LTE base station.

5. the system according to claim 4 for realizing LTE air interface multicast, which is characterized in that the 4G core net is also For exiting a group sowing time in user equipment, the ERAB modification request for making user equipment exit multicast is sent to LTE base station, it is desirable that repair Changing ERAB makes user equipment exit multicast；The LTE base station is also used to repair receiving the ERAB for making user equipment exit multicast After changing request, sends semi-persistent scheduling and release order to user equipment；The user equipment is also used to receiving semi-static tune After degree releases order, semi-persistent scheduling is discharged by RRC connection reconfiguration, does not use semi-persistent scheduling radio network temporary identifier Symbol receives data, to exit multicast.

6. the system according to claim 4 for realizing LTE air interface multicast, which is characterized in that when LTE base station needs to pass When defeated downlink multicast data, data are received using the down link control information notifying user equipment of activation semi-persistent scheduling；It is complete After transmitting at data, stop receiving data using the down link control information notifying user equipment for deactivating semi-persistent scheduling.