CN1996814A - A traffic control method - Google Patents

Abstract

The present invention relates to the communication field, in particular to a flow control method. In the ARQ mechanism applied to the long-term evolution network, it is characterized in that it includes: the sending end sends data to the receiving end; the receiving end detects the transmission error rate, and when it exceeds a set first threshold, sends a flow control instruction to the peer entity; The terminal controls the transmission flow according to the instruction. According to the new transmission requirements of the LTE network, the present invention performs flow control on special scenarios under some new mechanisms, assists these mechanisms to achieve better transmission effects, and optimizes network switching and high-level retransmission.

Description

A Flow Control Method

technical field

The invention relates to the communication field, in particular to a flow control method in a long-term evolution network.

Background technique

UMTS Universal Mobile Telecommunication Systems (UMTS Universal Mobile Telecommunication Systems) is a third-generation mobile communication system that uses the air interface of WCDMA Wide-band Code Division Multiple Access (WCDMA Wide-band Code Division Multiple Access). The UMTS system is also usually referred to as the WCDMA communication system.

Functionally, network units can be divided into RAN Radio Access Network and CN Core Network. Among them, the wireless access network is used to handle all wireless-related functions, while the CN handles the switching and routing of all voice calls and data connections in the UMTS system and external networks. Its system structure is shown in Figure 1.

The network units of the UMTS system include UE User Equipment, UMTS Terrestrial Radio Access Network (UTRAN UMTS Terrestrial Radio Access Network), CN, and OMC Operation and Maintenance Center (OMC Operation and Maintenance Center) functional entities. The system network structure is shown in Figure 2 shown.

Figure 2 also shows the main interfaces of the WCDMA system. The Uu interface is the wireless interface of WCDMA. The UE accesses the fixed network part of the UMTS system through the Uu interface, but the Iu interface is an interface connecting UTRAN and CN. The Iur interface is an interface connecting RNCs. The Iur interface is a specific interface of the UMTS system and is used for mobility management of the mobile station in the RAN. The Iub interface is the interface connecting the Node B (Node B) and the Radio Network Controller (RNCRadio Network Controller).

The wireless interface generally refers to the Uu interface between the UE and the network. The protocol structure of the wireless interface is shown in Figure 3, where:

GC: general control;

BMC: broadcast/multicast control protocol;

Nt: notification;

RLC: radio link control;

DC: dedicated control;

MAC: Media Access Control;

RRC: Radio Resource Control;

PHY: physical layer;

PDCP: Packet Data Convergence Protocol.

The wireless interface is divided into three protocol layers, namely physical layer (L1), data link layer (L2) and network layer (L3).

Among them, L2 includes four sublayers including MAC, RLC, PDCP, and BMC.

The functions of the MAC sublayer include: mapping between logical channels and transport channels; selection of an appropriate transport format for each transport channel; priority processing between UE data streams; priority processing between UEs using a dynamic pre-arrangement method ;Priority processing between data streams of several users on DSCH and FACH;Identification of UE on common transport channel;Multiplexing high-level PDUs into transport blocks transmitted to the physical layer through the transport channel, and from the physical layer through the transport channel Layer transport block demultiplexing into high-level PDU; traffic monitoring; dynamic transmission channel type switching; transparent RLC encryption; access service level selection.

Both MAC-d and MAC-c/sh/m on the network side have flow control entities, and control flow through buffering and so on. As shown in Figure 4 and Figure 5.

RLC sublayer functions: segmentation and reassembly, concatenation, padding, transmission of user data, error detection, sending high-level PDUs in sequence, copy detection, flow control, sequence number check of unconfirmed data transmission mode, protocol error detection and recovery, encryption, hanging start and restore functions. The RLC layer performs flow control through the transmission buffer of the sending end and the receiving window of the receiving end.

In the existing UMTS R6 system, real-time services are generally transmitted in RLCUM mode, and the MAC layer can choose HSDPA or DCH to carry according to the services. The segmentation and concatenation of RLC UM PDU is completed according to the instructions of the MAC layer.

At the 3GPP TSG RAN#26 meeting, the research project "Evolved UTRA and UTRAN" or LTE (Long Term Evolution) was passed. The reason for establishing this project is: With the introduction of enhanced technologies such as HSDPA and Enhanced Uplink, 3GPP wireless access technology will have high competitiveness in the next few years. However, in order to ensure competitiveness for a longer period of time (such as 10 years or longer), the long-term evolution of the 3GPP radio access technology needs to be considered.

Important parts of this long-term evolution include reduced latency, higher user data rates, improved system capacity and coverage, and reduced costs for operators. In order to achieve the above goals, both the evolved radio interface and radio network structure should be considered.

In order to meet the various performance requirements of this long-term evolving network, the network structure, wireless interface, and protocol stack functions will all be improved accordingly. The existing protocol layer structure results in many repetitive functions, such as retransmission, split concatenation, etc. of the RLC and MAC sublayers. In order to reduce latency and simplify the protocol, these repetitive functions must be considered streamlined. In addition, the all-IP requirement proposed by the LTE system, that is, all network transmissions are based on IP packet services, requires a corresponding mechanism to ensure this new requirement.

In the LTE network, the network structure has changed from the original 3-layer node structure to a 2-layer node structure, and the RNC function is divided into Node B and gateway node (GW Gateway). In the future evolution network, more services with different requirements will need to be considered in the design. New technologies such as IP transport shared channel on Node B increase the requirement of MAC for flow control function. In some scenarios, the necessary flow control can optimize the service transmission of different QoS.

In the discussion of LTE network, due to the use of shared channels, soft handover is canceled, and how hard handover can meet the needs of evolved networks, some auxiliary mechanisms are proposed, such as data forwarding or Bi-casting.

As shown in Figure 6, it is a dataforwarding solution under the network structure without interface between SNB and TNB in the prior art. It can be seen from the figure that it mainly includes the following steps:

S011. The UE sends a measurement report to the source eNode (SNB);

S012, the SNB makes a measurement judgment;

S013, the SNB sends a handover preparation request to the target evolved node (TNB), which includes some capacity information and context information;

S014. The TNB reserves resources for the UE;

S015, the TNB and the GW establish a user plane connection;

S016. The TNB sends a preparation completion message to the SNB and sends a path switching instruction to the GW;

S017. After receiving the preparation completion indication, the SNB sends a handover indication to the UE;

S018. At the same time, the SNB stops the transmission and sends the unsent data in its own cache and the unacknowledged data in the retransmission cache to the TNB;

S019. Since there is no interface between the SNB and the TNB, the data needs to be forwarded from the GW;

S0110, after all the SNB data is sent to the GW, the GW starts to send data to the TNB;

S0111. The TNB buffers and schedules the data;

S0112. After receiving the handover command, the UE starts the L1 synchronization process, and prepares to establish a connection with the TNB;

S0113, send the H/O confirm message to TNB after completing the synchronization;

S0114, TNB starts to send data after receiving it;

S0115, and send the H/O completion indication to the SNB;

S0116. The SNB releases the corresponding data plane connection with the GW.

As shown in FIG. 7 , it is a schematic flowchart of a dataforwarding solution in the prior art under the network structure with an interface between the SNB and the TNB.

Besides, more auxiliary measures are considered to improve the performance of hard handover. This includes flow control.

As a function that the LTE system must still retain, ARQ may be implemented in GW or Node B. ARQ is to ensure the correct transmission of non-real-time services that require a high bit error rate. ARQ has certain negative effects on delay and air interface resource usage. Impact.

The technical scheme of prior art one:

In the existing ARQ mechanism, the receiving end and the sending end control the traffic through the sending window and the receiving window. If the SN of the sent data is greater than the maximum value of the predetermined sending PDU, the PDU will not be sent; if the PDU sequence number received by the receiving end is If it is greater than the predetermined highest value of SN, delete the corresponding PDU. If the sender cannot receive the confirmation of the PDU for a long time, it will delete the PDU or start the restart of the peer entity and re-synchronize. As shown in Figure 8, it mainly includes the following steps:

The sender divides and concatenates the data from the upper layer into data blocks of the same size, adds headers, including numbering, and puts them in the retransmission buffer and transmission buffer to wait for MAC instructions.

After receiving the MAC instruction, set other fields in the header to be encrypted and sent to the MAC layer.

After receiving the PDU, the receiving end decrypts and reorders according to the sequence number.

If it is found that there are data packets that have not been received, that is, the sequence numbers are not continuous, a status report is generated and sent to the other entity to tell it which data packets have been received and which have not been received.

After receiving the status report, the receiving end retransmits the corresponding PDU.

In addition, the sending end can also add a polling bit in the data packet to be sent, and the receiving end sends a status report immediately or periodically after receiving this bit.

The receive window and send window are accomplished through a series of state variables:

The state variable VT(S) at the receiving end represents the sequence number of the next PDU to be sent, and VT(A) represents the sequence number of the last confirmed PDU+1, which is the lower limit of the sending window. VT(MS)=VT(A)+window_size indicates the PDU with the highest sequence number that the sender can send, that is, the upper limit of the send window. window_size is a fixed value configured by the network. If the sequence number of the next PDU to be sent is greater than VT(MS), the sender does not send it.

In addition, every time a data packet is retransmitted, the VT (DAT) will be +1 until it reaches the predetermined threshold MaxDAT. After reaching, the corresponding SDU can be deleted or the entity can be restarted according to the network configuration.

The variable at the receiving end has VR (R) indicating the sequence number of the last PDU received in sequence + 1, and the PDUs before this sequence number will be reorganized into SDUs and sent to the upper layer accordingly. This serial number is the lower bound of the receiving window.

VR(H) indicates the highest sequence number of the PDU received by the receiving end.

VR(MR)=VR(R)+Configured_Rx_Window_Size indicates the sequence number of the first PDU that will be rejected by the receiving end. That is, the upper bound of the receiving window. Here Configured_Rx_Window_Size is a fixed value of network configuration. If a PDU with sequence number greater than or equal to VR(MR) is received, the receiving end will delete the received data.

There is no window mechanism guarantee for the transmission of the existing UM RLC, and the flow control is completed between the RLC and the MAC through the data volume indication of each TTI. RLC and upper layers complete dynamic adjustments through flow control frames. UM RLC is an RLC entity in unacknowledged mode. At each TTI time, MAC sends instructions to RLC to say how many data packets are needed, and how many, RLC sends corresponding data packets to MAC according to this instruction. The negotiation of the data rate between the RLC and the upper layer, that is, the IU port, is completed through the flow control frame, that is, the corresponding signaling is used for the RLC to notify the upper layer of its desired transmission rate.

The shortcoming of above-mentioned prior art one is:

In the LTE system, all-IP transmission will cause a large amount of data, and the flat two-layer structure puts a lot of data pressure on NodeB, so the requirements for flow control are also very high. The simple flow control of the existing system cannot meet the requirements of the evolving network.

The LTE system has higher requirements for some mechanisms such as handover and ARQ, such as higher requirements for the delay of ARQ, and higher requirements for the delay and packet loss rate of hard handover. Some auxiliary mechanisms such as bi-casting, data forwarding, etc. are considered to optimize switching. At this time, flow control needs to consider optimizing transmission in these special scenarios.

Contents of the invention

The invention provides a flow control method to solve the problem that the flow control mechanism in the LTE system cannot meet the requirements.

The inventive method comprises:

A flow control method, applied in the ARQ mechanism of the long-term evolution network, comprising:

The sender sends data to the receiver;

The receiving end detects the transmission error rate, and when it exceeds the set first threshold, sends a flow control instruction to the sending end;

The sending end controls the transmission flow according to the indication.

The first threshold may be one of the following:

The threshold value of the ratio of correctly received PDUs in the receive buffer;

Status report trigger frequency threshold;

The frequency threshold for receiving PDUs that exceed the upper limit of the receive window.

The flow control instruction can be carried by one of the following contents:

display signaling;

The most recently generated status report;

MAC control PDU.

The flow control indication can be one of the following:

A single bit indicates that the packet loss rate is too high;

The one with the highest packet loss rate and the smallest sequence number including the unreceived PDU;

The proportion of PDUs not received correctly.

According to the instruction, the sending end negotiates with the upper layer to control the transmission flow, including one or a combination of the following:

Notify the upper layer to stop sending new data, and send the data in the retransmission buffer to the peer entity first;

Notify the upper layer to reduce the rate at which new data arrives at the MAC, stop transmitting new data, and send retransmitted data to the peer entity first;

Stop the transmission of new data, give priority to retransmission data, notify the high-level MAC transmission buffer capacity, and request to reduce the transmission rate.

The described method also includes the steps of:

When it is detected that the transmission error rate is lower than the set first threshold, the flow control is released.

The detection of whether the transmission error rate is lower than the set first threshold is completed by the sending end or the receiving end.

A flow control method, applied in the ARQ mechanism of the long-term evolution network, comprising:

The sender sends data to the receiver;

The sending end detects the transmission error rate, and performs flow control when it exceeds the set second threshold.

The second threshold may be one or a combination of the following:

The number of PDUs in the retransmission buffer is higher than the threshold;

The PDU in the transmission buffer is higher than the threshold value;

The frequency of receiving status reports is higher than the threshold.

The flow control includes one or a combination of the following:

Stop sending new data, give priority to sending retransmission data, and instruct the upper layer to adjust the transmission rate of the upper layer;

Instruct the upper layer to stop sending new data, and give priority to retransmission data to the peer entity

The described method also includes the steps of:

After detecting that the transmission error rate is lower than the set second threshold, the flow control is released.

The detection of whether the transmission error rate is lower than the set second threshold is completed by the sending end or the receiving end.

A flow control method, applied in the hard handover of the long-term evolution network, is characterized in that, comprising:

After the source eNodeB receives the switching instruction, it conducts traffic negotiation with the data receiving end;

The data receiving end sends a transmission rate indication to the source eNodeB, carrying transmission rate information;

The source eNB transmits data according to the transmission rate information.

The data receiving end is a gateway node.

In the traffic negotiation, the source evolved Node B reports data volume information or transmission rate information to the gateway node, and the gateway node instructs the source evolved Node B to transmit the rate.

The reported data amount information or transmission rate information is carried by the transmission context message sent by the source eNodeB to the target eNodeB, and the gateway node indicates the transmission rate of the source eNodeB.

The traffic negotiation further includes that the source evolved Node B sends an expected rate indication to the gateway node, and is confirmed by the gateway node.

The method also includes:

After the gateway node receives the path switching instruction, it conducts traffic negotiation with the target eNodeB;

The gateway node transmits data to the target eNB according to the transmission rate information indicated by the traffic negotiation result information.

The gateway node performs traffic negotiation with the target eNodeB, and sends data volume information to the target eNodeB for the gateway node, and the target eNodeB reports the rate.

The gateway node performs traffic negotiation with the target eNodeB, sends an expected rate indication to the target eNodeB for the gateway node, and is confirmed by the target eNodeB.

The gateway node conducts traffic negotiation with the target eNodeB, and the gateway node controls the rate sent to the target eNodeB.

The gateway node performs traffic negotiation with the target eNodeB, which is completed in the initial RAB establishment phase.

The data receiving end is the target eNodeB.

In the traffic negotiation, the source eNodeB reports data volume information to the target eNodeB, and the target eNodeB instructs the source eNodeB to transmit the rate.

The reported data amount information is carried by the transmission context sent by the source eNodeB to the target eNodeB, and the target eNodeB notifies the source eNodeB of the transmission rate.

The traffic negotiation further includes that the source eNodeB sends an expected rate indication to the target eNodeB, and is confirmed by the target eNodeB.

A flow control method applied in hard handover of a long-term evolution network, comprising:

The target eNodeB sends a multicast instruction to the gateway node, and the gateway node conducts traffic negotiation between the source eNodeB and the target eNodeB;

The gateway node multi-sends data to the source eNodeB and the target eNodeB with indication information according to the traffic negotiation result.

In the traffic negotiation, the target eNodeB and the source eNodeB report buffer information or expected transmission rate information respectively, and the gateway uses the lower one as the traffic negotiation result.

In the method, the buffer information or the transmission rate sent by the target eNodeB and the source eNodeB to the gateway are carried by multiple indications.

In the traffic negotiation, the gateway node sends the expected transmission rate to the target eNodeB and the source eNodeB, and takes the lower required rate as the traffic negotiation result.

The multiple hairs are double hairs.

According to the new transmission requirements of the LTE network, the present invention performs flow control on special scenarios under specific mechanisms, assists these mechanisms to achieve better transmission effects, and optimizes network switching and high-level retransmission.

Description of drawings

FIG. 1 is a schematic diagram of the application of UMTS in the prior art;

FIG. 2 is a schematic structural diagram of UMTS in the prior art;

FIG. 3 is a schematic structural diagram of a wireless interface protocol in the prior art;

FIG. 4 is a schematic structural diagram of a MAC-d flow control entity in the prior art;

FIG. 5 is a schematic structural diagram of a MAC-c/sh/m flow control entity in the prior art;

Fig. 6 is a schematic flow chart of data forwarding without interface between SNB and TNB in the prior art;

Fig. 7 is a schematic flow chart of data forwarding with interface between SNB and TNB in the prior art;

FIG. 8 is a schematic flow chart of an ARQ mechanism in the prior art;

Fig. 9 is a schematic flow chart of Embodiment 1 of the present invention;

Fig. 10 is a schematic flow chart of Embodiment 2 of the present invention;

Fig. 11 is a schematic flow chart of Embodiment 3 of the present invention;

Fig. 12 is a schematic flow chart of Embodiment 4 of the present invention;

Fig. 13 is a schematic flow chart of Embodiment 5 of the present invention.

Detailed ways

The specific implementation manners of the present invention will be described below in conjunction with each other.

For ARQ services, the present invention can use timely flow control to decelerate processing control in the case of high retransmission rate, so that the receiving and sending peer entities will not lose synchronization, restart or data loss caused by congestion. Both the receiver and the sender can detect the retransmission rate, indicating the control flow.

For the hard handover solution, if bi-casting is used to assist the hard handover, the GW and the two NBs need to use flow control and slow down processing to prevent NB congestion when performing bi-casting. If data forwarding is used to assist, traffic negotiation between SNB and TNB (or GW), select an appropriate rate for transmission, and at the same time control the rate from GW to TNB (if forwarding from GW is required) to avoid problems caused by excessive rate during handover data loss.

The implementation of the present invention will be described below in combination with specific examples.

Example 1:

As shown in FIG. 9 , it is a schematic flow chart of Embodiment 1 of the present invention. Embodiment 1 is applied to the ARQ mechanism of the long-term evolution network, and the receiving end performs related control. It can be seen from the figure that Embodiment 1 mainly includes the following steps:

S11. The sending end sends data to the receiving end;

S12. The receiving end detects the transmission error rate, and when it exceeds a set first threshold, sends a flow control instruction to the peer entity;

The receiver detects the error transmission rate and compares it with the set threshold. When the error transmission rate is higher than the set threshold, it starts flow control and sends a flow control instruction to the peer entity.

The setting of the error transmission rate threshold in step S12 can adopt the following scheme:

The proportion of PDUs not received correctly in the receiving buffer reaches a certain limit;

Or the status report trigger frequency exceeds a certain limit;

Or the frequency of receiving PDUs exceeding the upper limit of the receiving window exceeds a certain limit;

The above content is the triggering standard and measurement condition. If the proportion of PDUs that are not received correctly in the receiving buffer reaches a certain limit, the transmission error rate is considered to be high, and so on.

The flow control instruction is sent by the receiving end to the sending end (peer entity), and this instruction can be passed through:

Display signaling, that is, physical layer or MAC signaling indication;

Or carry it along in the latest status report generated;

Or in other MAC Control PDUs.

The above flow control indication can be:

A single bit indicates that the packet loss rate is too high;

Or the one that indicates a high packet loss rate and includes the smallest sequence number of PDUs that have not been received;

Or indicate the receiving end status such as the proportion of PDUs not received correctly.

S13. According to the instruction, the sending end negotiates with the upper layer to control the transmission flow;

After receiving this instruction, the sender can negotiate with the upper layer to reduce the transmission rate or/and buffer capacity, which can include the following:

Notify the high-level to stop sending new data, give priority to sending the data in the retransmission buffer to the receiving end, after a period of time (timer control, etc.) resume the high-level transmission or resume the high-level transmission if the data in the retransmission buffer is less than a certain limit;

Notify the upper layer to reduce the rate at which new data arrives at the MAC (according to the instruction of the peer entity or/and the amount of data in the retransmission buffer/transmission buffer of the sending end itself) to stop transmitting new data, and send the retransmission data to the receiving end first;

Stop the transmission of new data, give priority to retransmission data, notify the high-level MAC transmission buffer capacity, and request to reduce the transmission rate.

S14. After detecting that the transmission error rate is lower than the set first threshold, the receiving end sends a flow control release instruction to the sending end.

The data receiving end sends an indication to the sending end after the retransmission rate decreases.

In this step S14, the sending end may also detect the error transmission rate. In this way, after the sending end detects that the error transmission rate is lower than the set first threshold, there is no need to send a flow control release instruction, and the flow control can be released directly.

Example 2:

As shown in FIG. 10 , it is a schematic flow chart of Embodiment 2 of the present invention. Embodiment 2 is applied to the ARQ mechanism of the Long Term Evolution network, and related control is performed by the sending end. It can be seen from the figure that Embodiment 2 mainly includes the following steps:

S21. The sending end sends data to the receiving end;

S22. The sending end detects the transmission error rate, and performs flow control when it exceeds a set second threshold.

When the sender detects that the transmission error rate is higher than the set second threshold, flow control is performed. The setting of the second threshold refers to the following:

The number of PDUs in the retransmission buffer is higher than a certain limit;

or/and the PDUs in the transmit buffer are above a certain limit;

Or/and the frequency of receiving status reports is above a certain limit.

The content of the flow control can be adjusted by the data sender as follows:

Stop sending new data, give priority to sending retransmission data, and instruct the upper layer to adjust the (highest) transmission rate of the upper layer.

Instruct the upper layer to stop sending new data, give priority to retransmission data to the peer entity, and send an instruction to the upper layer to resume transmission when the transmission buffer/status report detects that the transmission is normal; or use the timer to control the upper layer to continue transmission.

S23. After the sending end detects that the error transmission rate is lower than the set second threshold, it connects and cancels the flow control.

This process can also be completed by the receiving end. When the receiving end detects that the transmission error rate is lower than the set second threshold, it sends an instruction to release the flow control to the sending end. Flow control is released by the sender.

Example 3:

As shown in Figure 11, it is a schematic flow chart of Embodiment 3 of the present invention. Embodiment 3 is applied to the hard handover process of the long-term evolution network. There is no interface between the SNB and the TNB, and the data is forwarded through the GW. It can be seen from the figure that the embodiment 3 mainly includes the following steps:

S31. After receiving the handover instruction, the SNB performs traffic negotiation with the GW;

After receiving the GW (TNB) switching instruction, the SNB needs to forward the data in the transmission buffer (and the data in the retransmission buffer, if it is an ARQ service) from the GW to the TNB buffer for transmission.

Before sending data, SNB needs to conduct flow negotiation with GW. This data volume report can be carried in the transmission context message sent by SNB to TNB, or through other control messages.

In the traffic negotiation, the SNB reports data volume information or transmission rate information to the GW, and the GW instructs the SNB on the transmission rate. The reported data volume information or transmission rate information is carried in the transmission context message sent by the SNB to the TNB, and the GW indicates the transmission rate of the SNB.

The traffic negotiation may also include that the SNB sends an expected rate indication to the GW, and the GW confirms it.

S32. The GW sends a transmission rate indication to the SNB, carrying transmission rate information;

GW instructs SNB to transmit data at an appropriate transmission rate.

S33, the GW and the TNB perform traffic negotiation;

GW also needs to conduct traffic negotiation with TNB. This process can be completed during the initial RAB establishment phase. GW sends data to TNB at a lower initial rate to prevent data congestion at TNB. The TNB feeds back the buffer capacity to control data loss caused by data volume overflow during the handover preparation phase.

S34. The SNB transmits data according to the transmission rate information carried in the transmission rate indication.

In Embodiment 3, it may also include the process of traffic negotiation between the GW and the TNB, which may specifically include:

After the GW receives the path switching instruction, it conducts traffic negotiation with the TNB;

The GW transmits data to the TNB according to the transmission rate information indicated by the traffic negotiation result information.

The GW and the TNB perform traffic negotiation, and the GW sends data volume information to the TNB, and the TNB reports an appropriate rate.

The GW negotiates traffic with the TNB, sends the expected rate to the TNB for the GW, and is confirmed by the TNB.

The GW conducts flow negotiation with the TNB, and the GW controls the rate sent to the TNB.

The GW performs flow negotiation with the TNB, which is completed in the initial RAB establishment phase.

Example 4:

As shown in Figure 12, it is a schematic flow chart of Embodiment 4 of the present invention. Embodiment 4 is applied to the hard handover process of the long-term evolution network. SNB and TNB have an interface, and the data is directly sent. It can be seen from the figure that Embodiment 4 mainly includes The following steps:

S41. After receiving the handover instruction, the SNB performs traffic negotiation with the TNB;

After receiving the handover instruction, the SNB needs to send the data in the transmission buffer (and the data in the retransmission buffer, if it is an ARQ service) to the TNB for buffering to be sent.

Before sending data, SNB needs to conduct flow negotiation with TNB. This data volume report can be carried in the transmission context message sent by SNB to TNB, or through other control messages.

The traffic negotiation can be:

The SNB reports data volume information to the TNB, and the TNB indicates the transmission rate of the SNB. The reported data amount information is carried by the transmission context sent by the SNB to the TNB, and the TNB notifies the SNB of the transmission rate.

SNB sends expected rate indication to TNB, and is confirmed by TNB.

S42. The TNB sends a transmission rate indication to the SNB, carrying transmission rate information;

TNB instructs SNB to transmit data at an appropriate transmission rate.

S43. The SNB transmits data according to the transmission rate information carried in the transmission rate indication.

S44. The TNB needs to negotiate flow control with the GW, and the GW transmits new data to the TNB at a lower rate.

Example 5:

As shown in FIG. 13 , it is a schematic flow chart of Embodiment 5 of the present invention. Embodiment 5 is applied to the hard handover process of the LTE network, and the multi-cast mechanism is used to optimize the interruption time of the handover to realize smooth handover. Embodiment 5 is described by taking bi-casting as an example. As can be seen from the figure, Embodiment 5 mainly includes the following steps:

S51. The TNB sends a bi-casting instruction to the GW, carrying buffer information or a transmission rate instruction;

When the TNB sends the bi-casting instruction to the GW, it also carries buffer information or a transmission rate instruction.

S52. The GW performs traffic negotiation between the SNB and the TNB to obtain the transmission rate;

The GW acquires the transmission data rate information after the SNB and TNB traffic negotiation.

The traffic negotiation can be:

TNB and SNB respectively report buffer information or expected transmission rate information, and the gateway takes the lower one as the traffic negotiation result;

The GW sends the expected transmission rate to the TNB and the SNB, and takes the lower rate required by the two as the traffic negotiation result.

The buffer information or the transmission rate sent by the SNB and the TNB to the GW is carried by a dual-send instruction.

S53. The GW performs double transmission to the SNB and the TNB at the transmission rate.

In Embodiment 5, the GW performs double transmission to two base stations (or multiple transmissions to multiple base stations, if the multiple transmission mechanism is adopted) at a lower transmission rate according to the transmission rate information. This rate needs to satisfy the requirements of less capable base stations.

According to the new transmission requirements of the LTE network, the present invention performs flow control on special scenarios under some new mechanisms, assists these mechanisms to achieve better transmission effects, and optimizes network switching and high-level retransmission.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (31)

1, a kind of flow control method, is applied in the ARQ mechanism of long-term evolution network, is characterized in that, comprises: The sender sends data to the receiver; The receiving end detects the transmission error rate, and when it exceeds the set first threshold, sends a flow control instruction to the sending end; The sending end controls the transmission flow according to the indication. 2. The method according to claim 1, characterized in that the first threshold can be one of the following: The threshold value of the ratio of correctly received PDUs in the receive buffer; Status report trigger frequency threshold; The frequency threshold for receiving PDUs that exceed the upper limit of the receive window. 3. The method according to claim 1, wherein the flow control instruction can be carried by one of the following contents: display signaling; The most recently generated status report; MAC control PDU. 4. The method according to claim 1, wherein the flow control instruction can be one of the following: A single bit indicates that the packet loss rate is too high; The one with the highest packet loss rate and the smallest sequence number including the unreceived PDU; The proportion of PDUs not received correctly. 5. The method according to claim 1, characterized in that, according to the instruction, the sending end negotiates with the upper layer to control the transmission flow, including one or a combination of the following: Notify the upper layer to stop sending new data, and send the data in the retransmission buffer to the peer entity first; Notify the upper layer to reduce the rate at which new data arrives at the MAC, stop transmitting new data, and send retransmitted data to the peer entity first; Stop the transmission of new data, give priority to retransmission data, notify the high-level MAC transmission buffer capacity, and request to reduce the transmission rate. 6. The method of claim 1, further comprising the steps of: When it is detected that the transmission error rate is lower than the set first threshold, the flow control is released. 7. The method according to claim 6, wherein the detection of whether the transmission error rate is lower than the set first threshold is completed by the sending end or the receiving end. 8. A flow control method applied in an ARQ mechanism of a long-term evolution network, characterized in that, comprising: The sender sends data to the receiver; The sending end detects the transmission error rate, and performs flow control when it exceeds the set second threshold. 9. The method according to claim 8, wherein the second threshold can be one or a combination of the following: The number of PDUs in the retransmission buffer is higher than the threshold; The PDU in the transmission buffer is higher than the threshold value; The frequency of receiving status reports is higher than the threshold. 10. The method according to claim 8, wherein the flow control includes one or a combination of the following: Stop sending new data, give priority to sending retransmission data, and instruct the upper layer to adjust the transmission rate of the upper layer; Instruct the upper layer to stop sending new data, and give priority to retransmission data to the peer entity. 11. The method of claim 8, further comprising the step of: After detecting that the transmission error rate is lower than the set second threshold, the flow control is released. 12. The method according to claim 11, characterized in that the detection of whether the transmission error rate is lower than the set second threshold is completed by the sending end or the receiving end. 13. A flow control method applied to hard handover of a long-term evolution network, characterized in that it comprises: After the source eNodeB receives the switching instruction, it conducts traffic negotiation with the data receiving end; The data receiving end sends a transmission rate indication to the source eNodeB, carrying transmission rate information; The source eNB transmits data according to the transmission rate information. 14. The method according to claim 13, wherein the data receiving end is a gateway node. 15. The method according to claim 14, wherein the traffic negotiation is that the source eNodeB reports data volume information or transmission rate information to the gateway node, and the gateway node instructs the source eNodeB on the transmission rate. 16. The method according to claim 15, wherein the reported data amount information or transmission rate information is carried by the transmission context message sent by the source eNodeB to the target eNodeB, and the gateway node instructs the source eNodeB BTransfer rate. 17. The method according to claim 14, wherein the traffic negotiation further comprises that the source eNB sends an expected rate indication to the gateway node, and is confirmed by the gateway node. 18. The method of claim 14, further comprising: After the gateway node receives the path switching instruction, it conducts traffic negotiation with the target eNodeB; The gateway node transmits data to the target eNB according to the transmission rate information indicated by the traffic negotiation result information. 19. The method according to claim 18, wherein the gateway node conducts traffic negotiation with the target eNodeB, sends data volume information to the target eNodeB for the gateway node, and the target eNodeB reports the rate. 20. The method according to claim 18, wherein the gateway node conducts traffic negotiation with the target eNodeB, sends an expected rate indication for the gateway node to the target eNodeB, and is confirmed by the target eNodeB. 21. The method according to claim 18, wherein the gateway node conducts traffic negotiation with the target eNodeB, and the gateway node controls the rate sent to the target eNodeB. 22. The method according to claim 18, wherein said gateway node conducts flow negotiation with target eNodeB, which is completed in the initial RAB establishment stage. 23. The method according to claim 13, wherein the data receiving end is a target eNodeB. 24. The method according to claim 23, wherein the traffic negotiation is that the source eNodeB reports data volume information to the target eNodeB, and the target eNodeB instructs the source eNodeB to transmit the rate. 25. The method according to claim 24, wherein the reported data amount information is carried by the transmission context sent by the source eNodeB to the target eNodeB, and the target eNodeB notifies the source eNodeB to transmit rate. 26. The method according to claim 25, wherein the traffic negotiation further comprises the source eNodeB sending an expected rate indication to the target eNodeB, and being confirmed by the target eNodeB. 27. A flow control method applied to hard handover of a long-term evolution network, characterized in that it comprises: The target eNodeB sends a multicast instruction to the gateway node, and the gateway node conducts traffic negotiation between the source eNodeB and the target eNodeB; The gateway node multi-sends data to the source eNodeB and the target eNodeB with indication information according to the traffic negotiation result. 28. The method according to claim 27, wherein in the traffic negotiation, the target eNodeB and the source eNodeB report buffer information or expected transmission rate information respectively, and the gateway uses the lower one as the traffic Negotiation result. 29. The method according to claim 28, wherein the buffer information or the transmission rate sent by the target eNodeB and the source eNodeB to the gateway are carried by multiple indications. 30. The method according to claim 27, characterized in that in the traffic negotiation, the gateway node sends the desired transmission rate to the target eNodeB and the source eNodeB, and uses the lower required rate as the traffic Negotiation result. 31. The method according to claim 27, characterized in that said multiple shots are double shots.

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