CN1964318A - A method for downlink mapping of wireless access bearing in packet-switched domain - Google Patents

Abstract

The present invention relates to a method for downlink mapping of wireless access bearers in a packet switched domain, the core of which is: when constructing a corresponding IP message bearer structure through an initial call connection establishment process in a packet switched PS domain, first establish a PDP context and the corresponding radio access bearer RAB, and downlink mapping the RAB corresponding to the PDP context to the high-speed downlink shared channel HS-DSCH; and then transmitting the corresponding IP message based on the bearer structure. According to the present invention, according to the characteristics of the message transmitted at the initial stage of user access to the network, the wireless bearer of the message can be mapped to a reasonable wireless transmission channel, and a reasonable bandwidth can be provided to adapt to the bandwidth sharing of the IP network Features, meet the transmission of bursty IP flow, reduce or eliminate the waste of wireless bandwidth, reduce or eliminate the delay of bursty IP application layer signaling flow transmission, and eliminate the conflict between wireless side charging and network side charging.

Description

Method for downlink mapping of radio access bearer in packet switching domain

technical field

The present invention relates to the communication field, in particular to a method for downlink mapping of radio access bearers in a packet switching domain.

Background technique

In the Wideband Code Division Multiple Access (WCDMA) system, the access and transmission of broadcast domain (BC), circuit switched domain (CS) and packet switched domain (PS) are provided. The BC domain is used to provide broadcasting in the system, the CS domain is used to provide access and transmission of circuit-switched services, and the PS domain is used to provide access and transmission of packet services (mainly IP packets) . The network structure of the WCDMA system is as shown in Figure 1, including:

User equipment (UE), UMTS system terrestrial radio access network (UTRAN), core network (CN) and extranet. The CN includes GGSN and SGSN; the UTRAN includes a radio network controller (Radio Network Controller; RNC) and a system base station (NodeB).

In order to transmit IP packets through the PS domain, one or more activated packet data protocol contexts (Activated PDP Context) need to be established between the GGSN and the UE. The communication process when establishing PDP Context between GGSN and UE is as follows:

After the GGSN transmits the received IP message to the SGSN, it transmits it to the RNC through the Iu interface between the SSGN and the RNC, and then the RNC transmits it to the UE through the air interface Uu of the wireless link.

The PDP Context between SGSN and UE is transmitted through Radio Access Bearer (RAB). RAB establishment and release are controlled and initiated by SGSN and executed by UTRAN.

SGSN establishes RAB according to the QoS of different services, and maps it to Uu interface bearer and Iu connection (GTP-U Tuunel), and RNC maps it to radio interface bearer (RB), and RB is based on RNC and UE The wireless interface between them provides services for users, and its protocol structure is shown in Figure 2, mainly including wireless physical layer (PHY), media access control layer (MAC), radio link control layer (RLC) and packet data aggregation Protocol layer (PDCP).

The wireless physical layer (PHY) is used to provide a data transmission service of the Uu interface through a transport channel (Transport Channel).

The medium access control layer (MAC) is used to provide message scheduling and transmission through logical channels. The logical channel for transmitting data is a dedicated traffic channel (Dedicated Traffic Channel; DTCH). The logical channels need to be mapped to transport channels. A DTCH can be mapped to one or more transport channels. DTCH is in the downlink and can be mapped to a dedicated channel (Dedicated Channel; DCH), a forward access channel (Forward Access Channel; FACH, which belongs to the downlink common channel) and a high-speed downlink shared channel (High Speed Downlink Shared Channel; HS-DSCH) , which can be mapped to a dedicated channel DCH in the uplink, or a random access channel (Random Access Channel; RACH, which belongs to the uplink common channel).

The radio link control layer (RLC) is used to provide message transmission on a radio bearer (Radio Bearer; RB) through message fragmentation, reassembly, acknowledgment retransmission, sequencing, flow control, etc.

The packet data aggregation protocol layer (PDCP) is used to provide services such as distribution and compression of packets on the RB.

The structure of the protocol entity and service provider point of the Uu interface is shown in Figure 3, and it can be seen from the figure:

The SGSN first sends a radio access bearer establishment request (RAB Assignment Request) to the RNC. After the RNC receives it, it establishes a corresponding RB to bear the service on the RAB, and it may establish one or more RBs. Next, each RB needs to correspond to a PDCP entity (in some cases, the PDCP entity may not be used) and an RLC entity. Then an RLC entity can establish one or two DTCHs, and then transmit the PDU of the DTCHs to the MAC-d entity of the MAC layer, and the MAC-d entity performs scheduling.

In the process of transmitting the PDU of DTCH to the MAC-d entity of the MAC layer, it is necessary to first map different DTCHs to different transport channels, and then map the transport channels to physical channels for data transmission.

Wherein, the transmission channels are classified into three types: a dedicated transmission channel (DCH), a common transmission channel (RACH, FACH), and a shared transmission channel (HS-DSCH). Wherein the dedicated transmission channel is used to allocate a dedicated wireless channel to a certain user exclusively; the common transmission channel can be used by all users in the cell; the shared transmission channel can be used by all users in the cell Wireless channels are shared through high-speed scheduling of NodeB control signaling (HS-SCCH).

For example, the DCH is mapped to the dedicated physical channel (DPCH), the uplink common channel (RACH) is mapped to the physical random access channel (PRACH), the downlink common channel (FACH) is mapped to the secondary common control physical channel (S-CCPCH), and the downlink shared The channel (HS-DSCH) is mapped to the high-speed downlink physical channel (HS-PDSCH).

When the UE initiates a PS domain connection request, it will establish a primary packet data protocol context (Primary PDP Context). The UE transmits IP packets through the primary packet data protocol context. Later, when the UE needs to establish other specific services in the PS domain, such as VoIP services, it can establish a secondary packet data protocol context (Secondary PDP Context). There may be multiple secondary packet data protocol contexts, and each packet data protocol context corresponds to one RAB.

The prior art one related to the present invention is that in the 3GPP protocol, the UE first performs the call in the PS domain and the establishment process of the RAB, and then establishes the service through the IP application layer signaling, that is, changing the main PDP context and the RAB, expanding Bandwidth and change the corresponding QoS, the scheme of transmitting new business data on the original RAB.

When the UE initiates a connection request in the PS domain, it will establish a primary packet data protocol context (PrimaryPDP Context), and the primary PDP context is based on the RAB established on the DCH. The UE's PS domain call and RAB establishment process are shown in Figure 4, including:

Step 1. In order to establish a connection with the SGSN/GGSN, the UE must first establish an RRC connection with the RNC. At this time, the RNC will allocate DCH and DPCH to the 4 SRBs;

Step 2, UE establishes call connection with SGSN/GGSN;

Step 3, the UE initiates a PDP context activation request, requesting to establish a session context;

Step 4. After receiving this request, the SGSN will initiate a RAB establishment request, requesting establishment of a new RAB and sending information such as QoS required by the session to the RNC, where exact bandwidth requirements need to be specified;

Step 5. Because the wireless link-Radio Link has been established in the RRC Connection Setup process of step 1, in step 5, the RNC allocates and reserves a dedicated wireless channel according to the QoS requirements, and reconfigures the wireless link.

Step 6. The RNC initiates a radio bearer establishment request to the UE.

Step 7: The UE establishes a radio bearer according to the radio bearer establishment request, and sends a radio bearer establishment complete message to the RNC.

In steps 6 and 7, the radio bearer is established through the RRC signaling transmitted between the UE and the RNC, and the UE is configured, and the configuration information of the dedicated radio channel is sent to the UE. Add DCH and DPCH. A wireless bearer channel structure as shown in FIG. 5 is formed. The IP packet is sent to the UE through the radio bearer channel.

Step 8, RNC sends RAB establishment response to SGSN;

Step 9: The GGSN sends an Activation PDP Context Accept message to the UE.

At this point, the establishment of the main PDP context is completed, and the IP message can be transmitted between the network and the UE.

It can be seen from FIG. 5 that in the prior art, the RAB/RB of the primary PDP context is mapped to the DCH (there may be one or more DCHs depending on the implementation). The radio resource control signaling RRC (SRB1, SRB2, SRB3, SRB4) is mapped to another DCH. After all DCHs are multiplexed on a Coded Composite Transport Channel (CCTrCH), they are then multiplexed on one or more physical channels DPCH (the number and parameters of physical channels are determined according to the bandwidth and specific implementation).

The DCH is a dedicated resource. For a certain UE, after the DCH is established, its bandwidth is determined. Therefore, when the UE accesses the WCDMA PS domain, it must determine the bandwidth of the packet switching domain it needs. This is inconsistent with the access situation of actual users. The purpose of the user accessing the WCDMA PS domain is to connect to the Internet or other IP networks through it, and in the IP network, the real-time service is through the application layer signaling of the upper layer of the IP (messages belonging to the interactive or background class, such as SIP, HTTP, FTP, etc.), when the application layer signaling of the upper layer of IP has not been exchanged, real-time services such as session and stream services will not be established, so there is no way to determine the required bandwidth. Moreover, in 3G, the always-on that provides packet access, many times the UE is only connected to the network, but has no business.

The above-mentioned interactive (Conversational) and background (Background) IP packets are bursty data streams, and their traffic is not constant and unpredictable. It does not need to transmit data evenly. If it is transmitted on a dedicated channel, there will be some During the time, there is no data on the DCH channel, so it is easy to cause waste of wireless resources; but at other times, when burst traffic arrives, congestion occurs, which will increase the transmission delay of IP packets; when there are interactive When they appear at the same time as background messages, they will compete for the same dedicated channel resource, affecting the timely transmission of interactive messages. It can be seen from the above analysis that: the RAB of the primary PDP context is established on the DCH, and when the bandwidth of the dedicated radio channel configured for the UE is too large, especially when the UE is only connected to the network but has no business, it will cause waste of resources; If the bandwidth of the dedicated wireless channel is small, the network traffic will be affected, and the delay in establishing services for upper-layer applications will be affected. In addition, it will also bring difficulties to billing: dedicated channels with fixed bandwidth have been allocated in wireless, but in IP networks, billing is generally performed according to IP traffic, which will result in high operating costs; if charging is based on fixed bandwidth, The user's cost rises. This will cause a conflict between access side and network side charging.

The prior art 2 related to the present invention differs from the prior art 1 in that when a service is established through IP application layer signaling, a new active PDP context and a new RAB structure are established, and the new service is in The new RAB structure is a scheme for transmitting new service data on the wireless bearer channel structure as shown in FIG. 6 .

In Figure 6, the IP real-time service message (IP Real Time Packet) is independently mapped to another RAB of the DCH for transmission, and the IP application layer signaling and other ordinary IP messages are transmitted with another RAB, but The RAB is also established on the DCH. SIP and other application signaling on the upper layer of IP are also interactive services, and their traffic is not constant and unpredictable. If DCH is used for transmission, the above-mentioned problems will also occur.

As can be seen from the above analysis, the prior art has the following defects:

1. Not suitable for the sharing characteristics of IP network;

2. Not suitable for transmitting sudden interactive and background IP packets

3. It is easy to cause waste of wireless bandwidth or channel congestion, and increase the delay of IP packet transmission;

4. It is easy to cause the transmission delay of upper layer application signaling to increase;

5. It is not easy to bill or cause a conflict between wireless access side and network side billing.

Contents of the invention

The purpose of the present invention is to provide a method for downlink mapping of wireless access bearers in the packet-switching domain, through which, it can be mapped to a reasonable bandwidth according to the characteristics of the transmission of bursty interactive and background IP packets In order to be suitable for the bandwidth sharing characteristics of IP network; and it can reduce or eliminate the waste of wireless bandwidth, reduce or eliminate the delay of sudden IP application layer signaling flow transmission, and eliminate the conflict between wireless side charging and network side charging .

The purpose of the present invention is achieved through the following technical solutions:

The present invention provides a method for downlink mapping of radio access bearers in a packet switching domain, which includes:

A. When constructing the corresponding IP packet bearer structure through the call connection establishment process of the initial packet-switched PS domain, establish the PDP context and the corresponding radio access bearer RAB, and map the RAB corresponding to the PDP context to the high-speed On the downlink shared channel HS-DSCH;

B. Transmit corresponding IP packets based on the bearer structure.

Wherein, the step A specifically includes:

A1. When constructing the corresponding IP message bearer structure through the call connection establishment process of the initial packet-switched PS domain, establish a main PDP context between the UE and the RNC, and the RAB corresponding to the main PDP context;

A2. Map the RAB corresponding to the primary PDP context to the high-speed downlink shared channel HS-DSCH of the base station.

Wherein, the step A specifically includes:

A3. When constructing the corresponding IP message bearer structure through the call connection establishment process of the initial packet-switched PS domain, establish a primary PDP context and a secondary PDP context between the UE and the RNC, and RABs corresponding to the PDP contexts respectively;

A4. Setting the QoS service level corresponding to the primary PDP context and the secondary PDP context;

A5. Map the RABs corresponding to the primary PDP context and the secondary PDP context to the same high-speed downlink shared channel HS-DSCH of the base station.

Wherein, said step A also includes:

A6. Corresponding to the corresponding RAB, establish and set logical channels with different QoS service levels.

Wherein, said step A also includes:

A6. When the PDP context is established, the SRB corresponding to the RRC signaling is sequentially downlink mapped to the DCH and DPCH of the base station;

or,

A7. When establishing the PDP context, map the SRB downlink corresponding to the RRC signaling to the HS-DSCH of the base station.

Wherein, when the real-time service is established through the IP application layer signaling, the step A also includes:

A8. Establish a PDP context carrying real-time services and a corresponding RAB, and downlink map the RAB to a dedicated channel of the base station.

Wherein, when transmitting the IP common message and the IP application layer signaling message, the step B specifically includes:

B1. The GGSN at the entrance of the PS domain divides the IP message, and transmits the IP ordinary message and the IP application layer signaling message obtained after the distribution to the SGSN through different transmission channels, and then maps them to different RABs superior;

B2. Transmitting the IP message to the RNC through a channel corresponding to the RAB;

B3. The RNC maps the message to the corresponding logical channel DTCH through the PDCP layer;

B4. Map the logical channel DTCH to the same HS-DSCH transport channel, and send the message to the UE through the high-speed downlink shared channel HS-DSCH.

Wherein, when transmitting the IP common message and the IP application layer signaling message, the step B specifically includes:

B5. The ingress GGSN of the PS domain transmits the IP message to the SGSN through the corresponding transmission channel, and then maps it to the corresponding RAB;

B6. Transmitting the IP message to the RNC through a channel corresponding to the RAB;

B7. The RNC checks the IP message through the PDCP layer, and differentiates the priority of the message, and maps it to the corresponding logical channel DTCH respectively;

B8. Map the logical channel DTCH to the same HS-DSCH transport channel, and send the message to the UE through the high-speed downlink shared channel HS-DSCH;

or,

B9. The GGSN at the entrance of the PS domain divides the IP message, and transmits the IP ordinary message and the IP application layer signaling message obtained after the distribution to the SGSN through different transmission channels, and then maps them to different RABs superior;

B10. Transmitting the IP message to the RNC through channels corresponding to different RABs;

B11. The RNC checks the IP message transmitted from the channel corresponding to the same RAB through the PDCP layer, and after the message is prioritized, it is mapped to the corresponding logical channel DTCH;

B12. Map the logical channel to the same HS-DSCH transport channel, and send the message to the UE through the high-speed downlink shared channel HS-DSCH.

Wherein, in step B7 or step B11, the process of prioritizing the message specifically includes:

The RNC differentiates the priority of the message through the PDCP layer according to the priority field in the IP header, or according to the transport layer protocol type and port number in the IP header.

Wherein, when transmitting the IP radio resource control signaling message, the step B specifically includes:

B13, RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

B14. After the MAC-d layer processes the message, it is mapped to the DCH and DPCH channel allocated by the base station for the corresponding SRB, and is transmitted to the UE through the DCH and DPCH channel;

or,

B15, RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

B16. The MAC-d layer processes the message, maps it to the HS-DSCH channel of the base station, and transmits it to the UE through the HS-DSCH channel.

Wherein, when transmitting the IP real-time message, the step B specifically includes:

B17. After the IP real-time message is distributed at the entrance GGSN of the PS domain, the real-time message is transmitted to the SGSN through the corresponding transmission channel, and then corresponds to the corresponding RAB;

B18, the message corresponding to the RAB is transmitted to the RNC through the channel corresponding to the RAB, and is mapped to the corresponding logical channel DTCH by the PDCP layer of the RNC;

B19, the real-time message is transmitted to the MAC-d layer of RNC by the DTCH, and the real-time message is mapped to the corresponding DCH channel by the MAC-d layer;

B20. Multiplexing the DCH channel to a coded synthetic transport channel CCTrCH, then multiplexing the corresponding physical channel DPCH, and transmitting it to the UE through the DPCH.

Wherein, when transmitting the IP real-time message, the step B also includes:

B21. After the real-time service session ends, release the PDP context and the corresponding RAB established for the real-time service.

As can be seen from the technical solution provided by the present invention above, the present invention establishes a PDP context and a corresponding radio access bearer RAB when constructing a corresponding IP message bearer structure through the call connection establishment process of the initial packet switching PS domain, And the RAB corresponding to the PDP context is downlink mapped to the high-speed downlink shared channel HS-DSCH, so the characteristics of the message transmitted in the initial stage of the user's access to the network (burst, unpredictability, and delay-related High sensitivity, high reliability requirements), respectively map the radio bearer of the message to a reasonable wireless transmission channel, provide a reasonable bandwidth, to adapt to the bandwidth sharing characteristics of the IP network, and to meet the transmission of bursty IP flows , and at the same time reduce or eliminate the waste of wireless bandwidth, reduce or eliminate the delay of bursty IP application layer signaling flow transmission, and eliminate the conflict between wireless side charging and network side charging.

In addition, before the establishment of real-time services in the PS domain, the interactive IP application layer signaling messages are treated differently from ordinary IP messages, and are transmitted preferentially. For real-time services established through IP application layer signaling, a secondary PDP context is established, and its wireless link bearer is mapped to a reasonable wireless transmission channel to meet its real-time and fixed bandwidth requirements.

Description of drawings

Fig. 1 is a schematic diagram of the network structure of the WCDMA system and the transmission route of the IP data flow;

Fig. 2 is the structural representation of the protocol entity of Uu interface;

Fig. 3 is a schematic diagram of the logical structure of the protocol entity and the service provider point of the Uu interface;

FIG. 4 is a flow chart of PS domain call and RAB establishment signaling in prior art 1;

FIG. 5 is a schematic structural diagram of an IP data stream and a downlink wireless bearer channel in prior art 1;

FIG. 6 is a schematic structural diagram of a radio bearer channel mapped by a new RAB in prior art 2;

Fig. 7 is the PS domain call connection establishment signaling flow in the present invention;

FIG. 8 is a schematic diagram of a radio bearer structure for RAB mapping in the first embodiment provided by the present invention;

Fig. 9 is the flow chart that real-time service PDP context is set up and RAB is set up among the present invention;

FIG. 10 is a schematic structural diagram of a wireless bearer channel after a real-time service is established in the present invention;

FIG. 11 is a schematic structural diagram of a radio bearer channel mapped by an RAB in a second embodiment provided by the present invention;

FIG. 12 is a schematic structural diagram of a radio bearer channel mapped by an RAB in a fifth embodiment provided by the present invention;

FIG. 13 is a schematic structural diagram of a radio bearer channel mapped by an RAB in a sixth embodiment of the present invention.

Detailed ways

The present invention provides a downlink radio bearer mapping method for radio access bearers in the PS domain, the core of which is: when constructing the corresponding IP message bearer structure through the initial call connection establishment process of the PS domain, establish the PDP The context and the corresponding radio access bearer RAB, and downlink mapping the RAB corresponding to the PDP context to the high-speed downlink shared channel HS-DSCH.

The first embodiment provided by the present invention corresponds to the case where the received IP message is distributed by the GGSN and transmitted to the corresponding RAB, and the priority of the message is distinguished by the PDCP layer. The main idea is: when constructing the corresponding IP packet bearer structure through the call connection establishment process of the initial packet-switched PS domain, establish a primary PDP context and a secondary PDP context between the UE and the RNC, and set the primary PDP context The QoS service level corresponding to the secondary PDP context; one is the primary PDP context, which is used to transmit ordinary interactive/background IP packets, with lower priority; the other is the secondary PDP context, which is used to transmit IP application layer signaling , with higher priority. In the RABs corresponding to the PDP contexts, establish and set up two logical channels with different QoS service levels, one with a higher priority and one with a lower priority, which are used to transmit messages of different priorities respectively Ordinary IP message; mapping the RABs corresponding to the primary PDP context and the secondary PDP context to the same high-speed downlink shared channel HS-DSCH of the base station. And when the PDP context is established, the SRB corresponding to the RRC signaling is sequentially downlinked to the DCH and DPCH of the base station; when the real-time service is established through the IP signaling message, the PDP context carrying the real-time service and the corresponding RAB are established , and downlink mapping the RAB to a dedicated channel of the base station.

Call process of the present invention is shown in Figure 7, comprises:

Step 1. The UE establishes an RRC connection with the RNC, and allocates the DCH and DPCH to the corresponding SRB through the RNC.

In order to establish a connection with the SGSN/GGSN, the UE must first establish an RRC connection with the RNC. At this time, the RNC will allocate DCH and DPCH to the SRB. For example, as shown in Figure 8, the RNC allocates corresponding DCHs and DPCHs to 4 SRBs.

Step 2. The UE establishes a call connection with the SGSN/GGSN.

Step 3. The UE initiates a PDP context activation request to the SGSN/GGSN, requesting to establish a primary PDP context.

Step 4. After receiving the request, the SGSN will initiate a RAB establishment request, requesting the establishment of the RAB and sending the required QoS and other information to the RNC.

Step 5. The RNC reconfigures the radio link and notifies the NodeB to establish the HS-DSCH channel.

In step 5, the RNC does not need to allocate and reserve radio resources, but only needs to reconfigure the radio link and notify the NodeB to establish the HS-DSCH. After the NodeB allocates a suitable HS-SCCH to the UE, it returns the allocation result to the RNC.

Step 6, RNC sends the RRC signaling message of radio bearer setup (Radio Bearer Setup) to the UE, and configures the allocated HS-DSCH and HS-SCCH to the UE. The message includes two DTCH configuration information units, which are used to distribute IP packets with different priorities.

Step 7. After the UE establishes the radio bearer according to the RRC signaling, it sends the RRC signaling that the radio bearer establishment is completed to the RNC.

Through the process of step 6 and step 7, the radio bearer is established between the UE and the RNC, and the allocated HS-DSCH and HS-SCCH are configured to the UE (there is no information element related to DCH and DPCH in the Radio Beater Setup message, There are only information elements for configuring HS-DSCH and HS-SCCH), and two DTCH configuration information elements are included in the message, which are used to distribute IP packets with different priorities. The normal IP packet is sent to the UE through the radio bearer.

Step 8. The RNC sends a RAB establishment response to the SGSN.

Step 9: The GGSN sends an Activation PDP Context Accept message to the UE. So far, the main PDP context is established.

Step 10: In order to respectively transmit IP upper-layer application signaling and common interactive and background IP messages, the UE immediately sends a request to the SGSN/GGSN to establish a secondary PDP context. The QoS requirement of the secondary PDP context is different from that of the primary PDP context, and has a higher priority.

Step 11, SGSN/GGSN initiates the second RAB establishment request, the priority of this RAB is higher than the first RAB, and the RAB Assignment Request (RAB Assignment Request) of the Radio Access Network Application Part (RANAP) ) message to set the Signaling Indication (Signaling Indication) message unit, indicating that this RAB is used to transmit application layer signaling.

Step 12, RNC reconfigures the wireless link again, and establishes a new MAC-d flow, which is used to transmit IP application layer signaling and has a high priority.

RNC reconfigures the radio link again, but this time does not need to configure HS-DSCH and HS-SCCH, because for the same UE, there is only one HS-DSCH and its matching HS-SCCH. But need to set up new MAC-d flow, this MAC-d flow will transmit IP application layer signaling, has high priority, distinguishes (transmits common IP message) with the MAC-d flow established in step 5.

Step 13, the RNC sends a radio bearer establishment request message to the UE, and configures a new RB/RLC/DTCH for the UE. The priority of the DTCH is higher than the DTCH configured in step 6. The signaling message applied by the IP upper layer will be transmitted from the network to the UE through the radio bearer.

Step 14: After the UE establishes the radio bearer according to the RRC signaling, it sends the RRC signaling that the radio bearer establishment is completed to the RNC.

Step 15, the RNC returns a new RAB establishment success response to the SGSN.

Step 16, the GGSN sends a secondary PDP context accept message to the UE.

So far, the initial PS domain call connection establishment process is completed, and the radio bearer structure shown in Figure 8 is established, that is, after the UE connects to the PS domain, two PDP contexts with different QoS levels, primary and secondary, are established and Its corresponding RAB, such as RAB1 and RAB2 in the figure. The first RAB corresponding to the primary PDP context transmits ordinary IP packets, and the second RAB corresponding to the secondary PDP context transmits IP application layer signaling packets, which have a higher transmission priority. Corresponding to the first RAB, two DTCHs with different priorities are established, such as DTCH1 and DTCH2 in the figure; corresponding to the second RAB, a DTCH is established, such as DTCH3 as shown in the figure. In the end, a total of 3 DTCHs were established.

Among them, DTCH1 in RAB1 has a medium priority and is used to transmit high-priority ordinary IP packets; DTCH2 in RAB1 has the lowest priority and is used to transmit low-priority packets of ordinary IP packets; DTCH3 in RAB2 has priority The highest level is used to transmit IP application layer signaling.

Based on the above bearer structure, IP packets (IP application layer signaling packets and ordinary IP packets) can start to be transmitted between the network and the UE. The specific process of transmitting IP ordinary packets and IP application layer signaling packets includes:

Step 101, the GGSN at the entrance of the PS domain divides the IP message, and transmits the IP ordinary message and the IP application layer signaling message obtained after the distribution to the SGSN through different transmission channels, and then maps them to different on the RAB.

Because different RABs correspond to different PDP contexts, the offloading of downlink packets is implemented at the ingress GGSN of the PS domain (because the GGSN is connected to different external network entities, it is easier to distinguish between IP application layer signaling packets and ordinary IP packets), The GGSN transmits the downlink message to the SGSN through different transmission channels (the transmission channel corresponding to the secondary PDP context has a higher priority), and then corresponds to different RABs.

Step 102: Transmit the messages corresponding to different RABs to the RNC through the GTP-U channel of the Iu interface corresponding to the different RABs.

Step 103, the RNC checks the IP message through the PDCP layer, and distinguishes the priority of the message, and distributes the message with high priority to the logical channel DTCH with high priority; priority Low messages are distributed to the low priority logical channel DTCH.

When these different messages arrive at the RNC through the GTP-U channel of the Iu interface corresponding to different RABs, the RNC does not distinguish the messages of the two channels, but sends them out through different logical channels. Although these logical channels are all mapped to the same transport channel (HS-DSCH), they have different priorities, which can ensure that IP application layer signaling messages can be sent prior to ordinary IP messages.

When prioritizing the packets, the PDCP layer may perform prioritization according to the priority field in the IP header, or according to the transport layer protocol type and port number in the IP header.

Step 104: Map the logical channel to the same HS-DSCH transport channel, and send the message to the UE through the high-speed downlink shared channel HS-DSCH.

Since the HS-DSCH channel of downlink IP packets is characterized by high transmission bandwidth, shared by multiple users, short TTI (2ms), and retransmission function, an appropriate modulation and channel coding scheme is selected according to UE channel conditions and fast scheduling is performed. IP application layer signaling and ordinary IP packets belong to interactive and background services, which are bursty but do not require high real-time performance. The bandwidth of the packet flow is unpredictable and not transmitted at a constant rate. Transmission on the HS-DSCH channel has the following benefits:

In line with the sharing characteristics of IP networks, the bandwidth of HS-DSCH can be scheduled to other PDP contexts or other UEs during the time when there is no message flow, and will not occupy wireless bandwidth, which can reduce the waste of bandwidth; when there is a sudden IP When packet flows arrive, large bandwidth can be scheduled for these packet flows and sent to UE in time.

In addition, HS-DSCH has a retransmission function, and its TTI is short, and the retransmission cycle is also short, which can further improve transmission reliability and reduce transmission delay through a reasonable scheduling algorithm.

When a large flow of packets competes for HS-DSCH resources and congestion occurs, the HS-DSCH scheduler can prioritize packets with high priority.

The above describes the process of establishing the primary and secondary PDP contexts at the same time after the UE initiates the call connection of the PS domain, and transmits the IP application layer signaling message and the ordinary IP message respectively through the established primary and secondary PDP contexts the process of.

The process of transmitting the IP radio resource control signaling message is as follows:

First, the RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

Then, after the MAC-d layer processes the message, it maps it to the DCH and DPCH allocated by the base station for the corresponding SRB, and transmits it to the UE through the DCH and DPCH.

When the real-time service is established through IP application layer signaling, the wireless bearer mapping scheme and the real-time packet transmission scheme after the real-time service is established are described as follows:

After the real-time service (session or stream) is established through IP application layer signaling (such as SIP signaling), the present invention establishes a new RAB to bear the real-time service, and maps the RAB to a dedicated channel for transmission. The signaling process is shown in Figure 9, including:

In step 201, the UE initiates a request to activate a secondary PDP context, requesting to establish a session context.

Step 202, after the SGSN receives this request, it will initiate a RAB establishment request (the establishment of the second RAB), request to establish a new RAB and send information such as the QoS required by the session to the RNC, where it is necessary to specify the specific QoS of the conversational service .

Step 203, RNC allocates and reserves dedicated radio channel resources according to QoS requirements, notifies NodeB to reconfigure radio links, and adds DCH/DPCH dedicated channels for real-time services.

Step 204, the RNC sends a radio bearer setup (Radio Bearer Setup) RRC message to the UE, and configures the allocated DCH and DPCH to the UE.

Step 205: After the UE establishes a new radio bearer according to the RRC signaling, it sends the RRC signaling that the radio bearer is established to the RNC.

In step 204 and step 205, a new radio bearer RAB is established and configured for the UE through RRC signaling, and radio resource allocation is sent to the UE. Add DCH and DPCH (one or more DCH/DPCH may be configured according to business and radio resource conditions). A wireless bearer channel structure as shown in FIG. 10 is formed. IP real-time service packets (RT Packets) are sent to the UE through the radio bearer channel.

In step 206, the RNC sends an RAB establishment success response to the SGSN.

Step 207, the GGSN sends an Activation PDP Context Accept message to the UE.

So far, the establishment of the real-time service PDP context is completed, and the wireless bearer channel structure shown in Figure 10 is formed at the same time, and the real-time IP message can be transmitted between the network and the UE based on the wireless bearer channel structure.

It can be seen from FIG. 10 that through the establishment process of the real-time service PDP context, a new RAB and RB are established, such as RAB/RB3 in FIG. 10 , and a dedicated channel DCH is added to the original radio bearer (as shown in FIG. 8 ). It is used to transmit real-time packets (RT Packet, Real Time Packet), which not only can ensure the fixed bandwidth and delay requirements when transmitting real-time packets, but also for IP application layer signaling, still in the original secondary PDP context, still through It is sent on the high-speed downlink shared channel and is not mapped to a dedicated channel. When the real-time service session ends, RAB/RB3 will be released, and the wireless channel structure will return to the state shown in Figure 8 . The concrete transmission process of real-time IP message is described below in conjunction with Fig. 10:

Step 301: After the IP real-time message is distributed at the ingress GGSN of the PS domain, the real-time message is transmitted to the SGSN through the corresponding transmission channel, and then corresponding to the corresponding RAB.

After the IP downlink real-time message is distributed at the ingress GGSN of the PS domain, the real-time message is transmitted to the SGSN through the corresponding transmission channel, and then corresponds to the RAB/RB3 as shown in FIG. 8 .

Step 302: The message corresponding to the RAB is transmitted to the RNC through the channel corresponding to the RAB, and mapped to the corresponding logical channel DTCH through the PDCP layer of the RNC.

As shown in FIG. 8, the message corresponding to RAB/RB3 is transmitted to RNC through the channel corresponding to RAB/RB3, and is mapped to the corresponding logical channel DTCH through PDCP of RNC.

Step 303: Transmit the real-time message to the MAC-d layer of the RNC through the DTCH, and map the real-time message to a corresponding DCH channel through the MAC-d layer.

Step 304, multiplex the DCH channel into a coded composite transport channel (CCTrCH), then multiplex the corresponding physical channel DPCH, and transmit it to the UE through the DPCH.

After the real-time service session ends, the PDP context and the corresponding RAB established for the real-time service are released.

The present invention provides the second embodiment, which differs from the first embodiment in that when the PDP context is established, the SRB corresponding to the RRC signaling is downlink mapped to the HS-DSCH of the base station, that is, the SRB is downlink mapped to the HS-DSCH of the base station. The resources on the DCH are reconfigured to be mapped to the HS-DSCH, and the downlink DCH and DPCH channels are released at the same time. Finally, a radio bearer structure as shown in FIG. 11 is formed.

The call flow is still as shown in Figure 7, but in the messages in steps 5 and 6, in addition to including the establishment of the HS-DSCH message unit, it also needs to include the reconfiguration SRB message unit and map them to the HS-DSCH above, and also includes the unit for releasing the downlink DCH/DPCH.

The advantage of the third embodiment is that radio resources are further saved on the basis of the first embodiment, and the disadvantage is that it is not conducive to uplink power control and handover.

In this embodiment, the process of transmitting the IP radio resource control signaling message is specifically:

The RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

After the MAC-d layer processes the message, it maps it to the HS-DSCH channel of the base station, and transmits it to the UE through the HS-DSCH channel.

The third embodiment provided by the present invention corresponds to the case where the received IP message is only distributed through the GGSN, and not differentiated by the PDCP layer. The main idea is: when constructing the corresponding IP packet bearer structure through the call connection establishment process of the initial PS domain, a primary PDP context and the RAB corresponding to the primary PDP context are established between the UE and the RNC; Mapping the RAB corresponding to the primary PDP context to the high-speed downlink shared channel HS-DSCH of the base station. And when the PDP context is established, the SRB corresponding to the RRC signaling is sequentially downlinked to the DCH and DPCH of the base station; when the real-time service is established through the IP signaling message, the PDP context carrying the real-time service and the corresponding RAB are established , and downlink mapping the RAB to a dedicated channel of the base station.

Its call flow only includes the process of establishing the main PDP context as shown in FIG. 7 .

The process of transmitting ordinary IP packets and IP application layer signaling packets is as follows:

First, at the entrance of the PS domain, the GGSN splits the IP packets, and transmits the IP common packets and IP application layer signaling packets obtained after splitting to the SGSN through different transmission channels, and then maps them to different RABs. superior;

Secondly, the IP message is transmitted to the RNC through the channel corresponding to the RAB;

Then, the RNC maps the message to the corresponding logical channel DTCH through the PDCP layer;

Finally, the logical channel DTCH is mapped to the same HS-DSCH transport channel, and the message is sent to the UE through the high-speed downlink shared channel HS-DSCH.

The process of transmitting the IP radio resource control signaling message is as follows:

First, the RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

Then, after the MAC-d layer processes the message, it is mapped to the DCH and DPCH channels allocated by the base station for the corresponding SRB, and is transmitted to the UE through the DCH and DPCH channels;

The process of transmitting IP real-time packets includes:

First, after the IP real-time message is distributed at the ingress GGSN of the PS domain, the real-time message is transmitted to the SGSN through the corresponding transmission channel, and then corresponds to the corresponding RAB.

Secondly, the message corresponding to the RAB is transmitted to the RNC through the channel corresponding to the RAB, and mapped to the corresponding logical channel DTCH through the PDCP layer of the RNC.

Then, transmit the real-time message to the MAC-d layer of RNC through the DTCH, and map the real-time message to the corresponding DCH channel through the MAC-d layer.

Next, the DCH channel is multiplexed on a coded synthetic transport channel CCTrCH, and then multiplexed on the corresponding physical channel DPCH, and transmitted to the UE through the DPCH.

Finally, when the real-time service session ends, release the PDP context established for the real-time service and the corresponding RAB.

The present invention provides a fourth embodiment, which differs from the third embodiment in that when establishing a PDP context, the SRB corresponding to the RRC signaling is downlink mapped to the HS-DSCH of the base station, that is, the SRB is downlink mapped to the HS-DSCH of the base station. The resources on the DCH are reconfigured to be mapped to the HS-DSCH, and the downlink DCH and DPCH channels are released at the same time. The advantage of doing this is to further save wireless resources, but its disadvantage is that it is not conducive to uplink power control and handover.

Its call flow only includes the process of establishing the main PDP context as shown in Figure 7, and in the messages in steps 5 and 6, in addition to including the establishment of HS-DSCH message unit, it also needs to include the reconfiguration SRB message unit , and map them to the HS-DSCH, and at the same time include the unit for releasing the downlink DCH/DPCH.

At this time, the process of transmitting the IP radio resource control signaling message is specifically as follows:

First, the RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

Then, the MAC-d layer processes the message, maps it to the HS-DSCH channel of the base station, and transmits it to the UE through the HS-DSCH channel.

The fifth embodiment provided by the present invention differs from the above embodiments in that: when the UE initially accesses the PS domain, only one primary PDP context and the corresponding RAB are established to form a radio bearer as shown in Figure 12 structure. When all interactive and background messages are transmitted based on the wireless bearer structure, all transmitted interactive and background messages must be distinguished and distributed at the PDCP layer of the RNC.

The main idea of the process of establishing the wireless bearer structure is as follows:

When constructing the corresponding IP packet bearer structure through the call connection establishment process of the initial packet switching PS domain, establish the main PDP context between the UE and the RNC, and the RAB corresponding to the PDP context; the corresponding RAB establishment settings have different Logical channel for QoS class of service. All logical channels set by the RAB corresponding to the main PDP context are mapped to the same high-speed downlink shared channel HS-DSCH of the base station. And when the PDP context is established, the SRB corresponding to the RRC signaling is sequentially downlinked to the DCH and DPCH of the base station; when the real-time service is established through the IP signaling message, the PDP context carrying the real-time service and the corresponding RAB are established , and downlink mapping the RAB to a dedicated channel of the base station.

Its call flow only includes the process of establishing the main PDP context as shown in FIG. 7 .

The process of transmitting IP ordinary packets and IP application layer signaling packets includes:

First, the ingress GGSN of the PS domain transmits the IP message to the SGSN through the corresponding transmission channel, and then maps it to the corresponding RAB;

Secondly, the IP message is transmitted to the RNC through the channel corresponding to the RAB;

Then, the RNC checks the IP message through the PDCP layer, and differentiates the priority of the message, and maps it to the corresponding logical channel DTCH respectively;

Finally, map the logical channel DTCH to the same HS-DSCH transport channel, and send the message to the UE through the high-speed downlink shared channel HS-DSCH;

The process of transmitting the IP radio resource control signaling message is as follows:

The RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

After the MAC-d layer processes the message, it maps it to the DCH and DPCH channel allocated by the base station for the corresponding SRB, and transmits it to the UE through the DCH and DPCH channel;

The process of transmitting IP real-time packets is as follows:

First, after the IP real-time message is distributed at the ingress GGSN of the PS domain, the real-time message is transmitted to the SGSN through the corresponding transmission channel, and then corresponds to the corresponding RAB.

Secondly, the message corresponding to the RAB is transmitted to the RNC through the channel corresponding to the RAB, and mapped to the corresponding logical channel DTCH through the PDCP layer of the RNC.

Then, transmit the real-time message to the MAC-d layer of RNC through the DTCH, and map the real-time message to the corresponding DCH channel through the MAC-d layer.

Next, the DCH channel is multiplexed on a coded synthetic transport channel CCTrCH, and then multiplexed on the corresponding physical channel DPCH, and transmitted to the UE through the DPCH.

Finally, when the real-time service session ends, release the PDP context established for the real-time service and the corresponding RAB.

Other relevant content is the same as the above-mentioned embodiment and will not be described in detail.

When implementing the fifth embodiment, the discrimination algorithm of the PDCP layer will be relatively complicated.

The present invention provides a sixth embodiment, which differs from the fifth embodiment in that when establishing a PDP context, the SRB downlink corresponding to the RRC signaling is mapped to the HS-DSCH of the base station, that is, the SRB is downlink mapped to the HS-DSCH of the base station. The resources on the DCH are reconfigured to be mapped to the HS-DSCH, and all downlink dedicated channels (DCH and DPCH channels) are released at the same time. A radio bearer structure as shown in FIG. 13 is formed.

Its call flow only includes the process of establishing the main PDP context as shown in Figure 7, and in the messages in steps 5 and 6, in addition to including the establishment of HS-DSCH message unit, it also needs to include the reconfiguration SRB message unit , and map them to the HS-DSCH, and at the same time include the unit for releasing the downlink DCH/DPCH.

At this time, the process of transmitting the IP radio resource control signaling message is specifically as follows:

First, the RNC transmits the IP radio resource control signaling message to the MAC-d layer through different transmission channels of the corresponding SRB;

Then, the MAC-d layer processes the message, maps it to the HS-DSCH channel of the base station, and transmits it to the UE through the HS-DSCH channel.

As can be seen from the specific embodiments of the present invention described above, the first embodiment of the present invention is the optimal embodiment of the present invention, and it has the following effects:

When the UE initiates a PS domain call connection and establishes a primary PDP context and a secondary PDP context, they have different QoS and are used to transmit ordinary IP packets and IP application layer signaling packets respectively. Doing so can ensure that the QoS of IP packets with different priorities can be satisfied differently in the whole path from the network to the air interface. Since the high-priority transmission channel improves the ability of the IP application layer signaling message to be transmitted in time on the network, it can reduce the real-time service establishment delay. Utilizing the high bandwidth and fast scheduling of the high-speed downlink shared channel of the air interface, and setting the priority of IP application layer signaling packets higher than ordinary IP packets, the transmission capability of such packets on the air interface can be improved and the real-time Service establishment delay.

Since the two established PDP contexts are for transmitting interactive and background IP packets, they are transmitted on the high-speed downlink shared channel, relying on the high bandwidth, small TTI and high-speed scheduling of the channel to meet its bursty requirements. At the same time, the channel has the feature of multi-UE sharing. When a certain UE has no burst packet flow, it can be scheduled for other UEs to avoid the waste of wireless bandwidth.

In the same RAB, because the PDCP layer of the RNC distinguishes and distributes IP packets, it further ensures that IP packets with different priorities have different scheduling priorities in the same shared channel, which improves the efficiency of high-priority packets. timely transmission capability. At the same time, the complexity of network construction can be reduced because there is no need to distribute common IP packets in the GGSN.

Because the shared transmission channel is used, packet flow accounting can be adopted on the wireless access side, avoiding conflicts with network side accounting.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (12)

1, the method for the descending mapping of RAB in a kind of packet-switched domain is characterized in that, comprising:

A, connect when setting up the corresponding IP message of procedure construction bearing structure when the calling by initial packet switching PS territory, set up PDP Context and corresponding RAB RAB, and be mapped on the high speed downlink shared channel HS-DSCH the RAB of described PDP Context correspondence is descending;

B, transmit corresponding IP message based on described bearing structure.

2, method according to claim 1 is characterized in that, described steps A specifically comprises:

A1, when the calling by initial packet switching PS territory connects when setting up the corresponding IP message of procedure construction bearing structure, between UE and RNC, set up a main PDP Context, and the RAB of described main PDP Context correspondence;

A2, the RAB of described main PDP Context correspondence is mapped on the high speed downlink shared channel HS-DSCH of base station.

3, method according to claim 1 is characterized in that, described steps A specifically comprises:

A3, when the calling by initial packet switching PS territory connects when setting up the corresponding IP message of procedure construction bearing structure, between UE and RNC, set up main PDP Context and time PDP Context, and the corresponding respectively RAB of described PDP Context;

A4, the QoS grade of service of described main PDP Context and inferior PDP Context correspondence is set;

A5, the RAB of described main PDP Context and inferior PDP Context correspondence is mapped on the same high speed downlink shared channel HS-DSCH of base station.

4, according to claim 1,2 or 3 described methods, it is characterized in that described steps A also comprises:

A6, corresponding corresponding RAB set up the logic channel with different QoS grades of service are set.

5, method according to claim 4 is characterized in that, described steps A also comprises:

A6, when setting up PDP Context, the descending successively DCH that is mapped to the base station of the SRB of RRC signaling correspondence gone up and DPCH on;

Or,

A7, when setting up PDP Context, on the descending HS-DSCH that is mapped to the base station of the SRB of RRC signaling correspondence.

6, method according to claim 1 is characterized in that, when setting up real time business by IP application layer signaling, described steps A also comprises:

A8, the PDP Context of setting up the carrying real time business and corresponding RAB, and with on the descending dedicated channel that is mapped to the base station of described RAB.

7, method according to claim 1 is characterized in that, when transmission common message of IP and IP application layer signaling message, described step B specifically comprises:

B1, the inlet GGSN in the PS territory shunt the IP message, and the common message of the IP that will obtain after will shunting is transferred to SGSN by different transmission channels respectively with IP application layer signaling message, are mapped to respectively on the different RAB again;

B2, the passage by the RAB correspondence are given RNC with described IP message transmissions;

B3, described RNC are mapped to described message on the corresponding logic channel DTCH by the PDCP layer;

B4, described logic channel DTCH is mapped on the transmission channel of same HS-DSCH, and described message is sent to UE by described high speed downlink shared channel HS-DSCH.

8, method according to claim 4 is characterized in that, when transmission common message of IP and IP application layer signaling message, described step B specifically comprises:

The inlet GGSN in B5, PS territory arrives SGSN by corresponding transmission channel with the IP message transmissions, is mapped on the corresponding RAB again;

B6, the passage by the RAB correspondence are given RNC with described IP message transmissions;

B7, described RNC check described IP message by the PDCP layer, and after described message being carried out the differentiation of priority, are mapped to respectively on the corresponding logic channel DTCH;

B8, described logic channel DTCH is mapped on the transmission channel of same HS-DSCH, and described message is sent to UE by described high speed downlink shared channel HS-DSCH;

Or,

B9, the inlet GGSN in the PS territory shunt the IP message, and the common message of the IP that will obtain after will shunting is transferred to SGSN by different transmission channels respectively with IP application layer signaling message, are mapped to respectively on the different RAB again;

B10, the passage by different RAB correspondences are given RNC with described IP message transmissions;

B11, described RNC check from the described IP message of the channel transfer of same RAB correspondence by the PDCP layer, and after described message being carried out the differentiation of priority, are mapped on the corresponding logic channel DTCH;

B12, described logic channel is mapped on the transmission channel of same HS-DSCH, and described message is sent to UE by described high speed downlink shared channel HS-DSCH.

9, method according to claim 8 is characterized in that, among step B7 or the step B11, the process to described message carries out the differentiation of priority specifically comprises:

Described RNC according to the precedence field in the IP head, perhaps can carry out the differentiation of priority according to transport layer protocol type and the port numbers in the IP head by the PDCP layer to described message.

10, method according to claim 5 is characterized in that, when transmission IP radio resource control signaling message, described step B specifically comprises:

B13, RNC are transferred to the MAC-d layer with the different transmission channels of IP radio resource control signaling message by corresponding SRB;

After B14, described MAC-d layer are handled described message, it is mapped on the DCH and DPCH channel that distribute for corresponding SRB under the base station, and by described DCH and DPCH Channel Transmission to UE;

Or,

B15, RNC are transferred to the MAC-d layer with the different transmission channels of IP radio resource control signaling message by corresponding SRB;

B16, described MAC-d layer are mapped to it on HS-DSCH channel of base station after described message is handled, and give UE by described HS-DSCH Channel Transmission.

11, method according to claim 6 is characterized in that, when transmission IP real-time packet, described step B specifically comprises:

B17, IP real-time packet are after the inlet GGSN in PS territory shunts, and real-time packet is transferred to SGSN by corresponding transmission channel, correspond on the corresponding RAB again;

B18, give RNC, and be mapped on the corresponding logic channel DTCH by the PDCP layer of RNC with the described channel transfer of message by the RAB correspondence that corresponds on the RAB;

B19, described real-time packet is sent to the MAC-d layer of RNC, and described real-time packet is mapped on the corresponding D CH channel by described MAC-d layer by described DTCH;

B20, with on described DCH channel multiplexing to the CCTrCH Coded Composite Transport Channel CCTrCH, and then on the multiplexing corresponding physical channel DPCH, and send UE to by described DPCH.

12, method according to claim 11 is characterized in that, when transmission IP real-time packet, described step B also comprises:

B21, after real-time service session finishes, be released to PDP Context and corresponding RAB that real time business is set up.

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