WO2012159376A1

WO2012159376A1 - Video multicast method and device

Info

Publication number: WO2012159376A1
Application number: PCT/CN2011/078347
Authority: WO
Inventors: 刘洪盛; 李晓峰; 文光俊
Original assignee: 华为技术有限公司
Priority date: 2011-08-12
Filing date: 2011-08-12
Publication date: 2012-11-29
Also published as: CN103053183A; CN103053183B

Abstract

Provided are a video multicast method and device. The method includes: dividing a received multicast video stream data packet into at least two data packet types according to the importance thereof; dividing the stations in a multicast group into at least two groups according to the code rate of the multicast video stream, the rates of the stations in the multicast group and the number of stations, and determining the sending time, sending rate and the type of the data packet to be sent when sending video streams to each group; and sending a data packet with the corresponding type over the shared channel of the multicast group within the sending time at the corresponding sending rate. The embodiments of the present invention improve the utilization rate of the station resources in the multicast group and improve the throughput of the wireless local area network.

Description

Video multicast method and device

Technical field

The present invention relates to the field of information technology, and in particular, to a video multicast method and device. Background technique

With the development of wireless communication technology, wireless local area network (Wireless Local Area Network;

WLAN) is getting more and more attention. In a network video streaming application, if multiple clients simultaneously order the same video program, in order to save network resources, multicast technology is usually adopted: the destination address of the video data sent by the source node is the group of the on-demand video. The multicast address of the broadcast group, the access point (AP) of the multicast group receives the video stream sent by the source of the video stream, and then sends the video stream to the wireless channel in the multicast group, where the wireless channel is Shared channel, each station (Station; STA) in the group can receive the video stream.

In the prior art, when performing video multicast, when the AP sends a video stream to the radio channel in the multicast group, the AP transmits the video stream at the rate of the lowest rate STA to meet the transmission rate of all the STAs in the group. However, if the rate of the transmitted video stream is higher than the rate of the lowest rate STA, the STAs in the multicast group will not receive the video stream normally, which will waste the STA resources with higher rate in the multicast group. And the throughput of the wireless LAN is low. Summary of the invention

The embodiment of the invention provides a video multicasting method and device, which solves the problem of waste of site resources in a multicast group and low throughput of a wireless local area network in the prior art.

The embodiment of the invention provides a video multicasting method, including:

And dividing the multicast video stream data packet into at least two data packet types according to the importance of the received multicast video stream data packet;

According to the code rate of the multicast video stream, the rate of each station in the multicast group, and the number of sites, Each station in the multicast group is divided into at least two groups, and determines a sending time, a sending rate, and a type of the transmitted data packet of the video stream to each group, where the type of the transmitted data packet is the at least two At least one type of packet type;

During the transmission time, a corresponding type of data packet is transmitted on the shared channel of the multicast group at a corresponding transmission rate.

An embodiment of the present invention further provides an access point, including:

a classifying unit, configured to divide the multicast video stream data packet into at least two data packet types according to the importance of the received multicast video stream data packet;

a grouping unit, configured to divide each site in the multicast group into at least two groups according to a code rate of the multicast video stream, a rate of each station in the multicast group, and a number of sites, and determine to each group Transmitting a transmission time of the video stream, a sending rate, and a type of the transmitted data packet, where the transmitted data packet type is at least one of the at least two data packet types;

The multicast unit is configured to send, according to the sending time, a data packet of a corresponding type on the shared channel of the multicast group in the sending time.

The video multicast method and device provided by the embodiment of the present invention classify a data packet of an access point at a receiving point of a multicast video stream, group the stations in the multicast group, and determine a video transmission time and rate of each group. The packet type is such that, within the transmission time of each group, a corresponding type of data packet is transmitted on the shared channel of the multicast group according to the transmission rate of each group. Thereby, the utilization rate of the site resources in the multicast group is improved, and the throughput of the wireless local area network is improved. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a flowchart of an embodiment of a video multicast method provided by the present invention; 2 is a schematic diagram of a video multicast structure of a wireless local area network;

3 is a flowchart of still another embodiment of a video multicast method provided by the present invention;

4 is a schematic structural diagram of an embodiment of an access point provided by the present invention;

FIG. 5 is a schematic structural diagram of still another embodiment of an access point according to the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

FIG. 1 is a flowchart of an embodiment of a video multicast method according to the present invention. As shown in FIG. 1, the method includes:

S101. Divide the multicast video stream data packet into at least two data packet types according to the importance of the received multicast video stream data packet.

S102. Divide each station in the multicast group into at least two groups according to a code rate of the multicast video stream, a rate of each station in the multicast group, and a number of stations, and determine a sending time of sending the video stream to each group, The transmission rate and the type of the transmitted packet, the type of the transmitted packet is at least one of the at least two packet types.

S103. Send a corresponding type of data packet on the shared channel of the multicast group at a corresponding sending rate during the sending time.

The execution body of the above steps is the access point AP in the wireless local area network.

FIG. 2 is a schematic diagram of a video multicast structure of a wireless local area network. As shown in FIG. 2, a video stream source point (110) multicasts a multicast video stream to a backbone network (115), and the multicast address is a special D. Class-specific address. The wireless local area network includes wireless stations: STA (130), STA (140), STA (150), and STA (160), among others, STA (130), STA (140), and STA (150), etc., through the Internet group Internet Group Multicast Protocol (IGMP) The datagram requests to join the video stream multicast group (170) to the access point AP (120) of the WLAN, and the access point AP (120) of the WLAN receives the IGMP data packet sent by each station, and establishes the local multicast. In the information table, information such as STA (130), STA (140), and STA (150) is added to the multicast information table. The AP (120) searches for the multicast video stream sent by the video server on the Internet according to the multicast address applied by each site in the multicast group, and then starts receiving the multicast video stream.

On the one hand, after receiving the multicast video stream sent by the video server, the AP performs further general processing and scheduling on the multicast video stream at the Media Access Control (MAC) layer, and may further group according to the group. The importance of each data packet in the broadcast video stream, the multicast video stream data packet is divided into at least two data packet types, which can be divided into important class data packets and sub-important data packets, wherein important data types A packet can be the basic data necessary to ensure that each site in the group can play video. That is, important packets need to be sent to all sites in the multicast group; and sub-critical packets can be guaranteed at each site. On the basis of playing video, some extended data can improve the quality of video playback, and the sub-important data packets can be sent to some stations with higher receiving speed in the multicast group without sending to all stations in the group; further, The AP can also identify unimportant data from the data packets of the multicast video stream, that is, it can also classify non-weight from the multicast video stream. For a packet of a class, when the code rate of the multicast video stream is higher than the site with the highest receiving rate in the multicast group, the AP can discard these non-critical packets, that is, not send to any sites in the multicast group. A non-critical class of data packets.

After receiving the multicast video stream, the AP usually stores the multicast video stream in the local buffer unit. Therefore, the AP can estimate the multicast video stream according to the amount of data in the local buffer unit per unit time. The code rate.

It should be noted that the AP can only analyze the data of the network layer and the application layer of the multicast video stream, and analyze the importance of the data without performing a complete video decoding operation.

On the other hand, the AP may further divide each station in the multicast group into at least two groups according to the code rate of the multicast video stream, the rate of each station in the multicast group, and the number of stations. Specifically, the AP may group the several stations whose receiving rate is close according to the receiving rate of each station, and use the group in each group. The lowest reception rate of each station is used as the transmission rate for transmitting multicast video stream packets to the group. The AP can allocate the sending time of the sending video stream to each group, and the sum of the sending time of the video stream sent by the AP to each group is equal to the time when the AP receives the multicast video stream. The AP may multicast corresponding types of data packets to each site in the group at a determined transmission rate within the transmission time of each group.

The group with the lower receiving rate is called the low-speed group, and the group with the higher receiving rate is called the high-speed group. For the low-speed group, the AP can only send the packets of the important class. For the high-speed group, the AP can send the important packets to the group. Class data packets and sub-important class data packets; if the multicast video stream is further divided into non-essential class data packets, the AP may determine whether to send non-essential data according to the relationship between the code rate of the multicast video stream and the high-speed group receiving rate. Packet, if the code rate of the multicast video stream is lower than the receiving rate of the station in the high speed group, the AP may also send the non-essential type data packet to the high speed group if the code rate of the multicast video stream is higher than that of the high speed group. At the receiving rate, the AP can discard packets of non-essential classes and send only important class packets and sub-important class packets to the high-speed group.

It should be noted that when the AP sends a multicast video stream packet to each station in the multicast group, the AP sends the multicast video stream packet to the shared channel of the multicast group at a certain transmission rate. For each station in the network, the receiving rate is higher than the AP sending rate, and the data packet sent by the AP can be received. Since the receiving rate of the low-speed group is lower than that of the high-speed group, the data packets transmitted by the AP in the shared channel of the multicast group can be received by each station in the low-speed group or can be transmitted at a high speed during the transmission time of the low-speed group. Each site in the group was received. That is, each station in the high-speed group can receive the important type of data packets sent by the AP on the shared channel in the multicast group during the transmission time of the low-speed group. Therefore, during the transmission time of the high-speed group, the AP can The packets of the sub-important class are sent only on the shared channel of the multicast group for receiving by each station of the high-speed group, and the important class of data packets are not required to be sent within the transmission time of the high-speed group, thereby improving the channel in the multicast group. The utilization of resources reduces the amount of data sent by APs and improves multicast efficiency.

The video multicast method provided by the embodiment of the present invention classifies a data packet of an access point at a receiving point that receives a multicast video stream, groups the stations in the multicast group, and determines a video transmission time, rate, and data packet of each group. Type, so in the transmission time of each group, according to the transmission rate of each group in the multicast group The corresponding type of data packet is sent on the shared channel, thereby improving the utilization of the site resources in the multicast group and improving the throughput of the wireless local area network.

FIG. 3 is a flowchart of still another embodiment of a video multicasting method according to the present invention. As shown in FIG. 3, in this embodiment, a process for a station in a wireless local area network to join a multicast group to receive a video stream is provided. The example provides a specific implementation manner in which the AP divides each site in the multicast group into at least two groups according to the code rate of the multicast video stream, the rate of each station in the multicast group, and the number of sites. Includes:

S201. If a station in the WLAN needs to join a multicast group, the device sends an IGMP datagram to the AP that has the routing function in the WLAN.

After receiving the IGMP datagram, the AP creates and maintains a multicast information table locally in the AP. The multicast information table records the site, multicast address, and physical rate information of the participating multicast stations. The AP searches for the multicast video stream sent by the video server on the Internet according to the multicast address applied by each site in the multicast group, and then starts receiving the multicast video stream.

5203. The AP receives the multicast video stream data packet, and stores the multicast video stream data packet in the local buffer unit.

S204: The AP estimates a code rate of the multicast video stream according to the amount of data in the local buffer unit in a unit time.

The AP usually stores the multicast video stream in the local buffer queue. Therefore, the AP can estimate the bit rate of the multicast video stream according to the amount of data in the local buffer queue per unit time.

If the code rate of the multicast video stream is lower than the set code rate, the AP may send the multicast video stream data packet on the shared channel of the multicast group at the lowest receiving rate of each station in the multicast group. In this case, The AP can multicast the video stream at the lowest rate of each site in the multicast group, so that the AP can meet the current video stream bandwidth requirement. Therefore, the AP can no longer perform the steps after S205. If the code rate of the multicast video stream is greater than the set code rate, the AP needs to perform the steps subsequent to S205.

S205. The AP divides the multicast video stream data packet into at least two data packet types according to the importance of the received multicast video stream data packet. In an embodiment, the AP may divide the multicast video stream data packet into a packet type of an important class and a packet type of a sub-important class, where the data packets of the important class may be required for each site in the group to play video. The necessary basic data, that is, the important class of data packets need to be sent to all sites in the multicast group; and the less important class of data packets can be based on ensuring that each site can play video, and can improve the quality of video playback. Extended data, sub-important data packets can be sent to some stations in the multicast group with higher receiving speed, and do not need to be sent to all stations in the group; in another embodiment, the AP can also receive data from the multicast video stream. The packet identifies unimportant data, that is, the AP can classify the multicast video stream packet into an important class packet type, a sub-important class packet type, and a non-essential class packet type, when the multicast video stream is When the code rate is higher than the one with the highest receiving rate in the multicast group, the AP can discard these non-critical packets, that is, not send any non-destination to any station in the multicast group. Packet to the class.

It should be noted that after receiving the multicast video stream, the AP can parse only the data of the network layer and the application layer of the multicast video stream, and analyze the importance of the data without performing a complete video decoding operation.

S206. The AP divides each site in the multicast group into at least two groups according to a code rate of the multicast video stream, a rate of each site in the multicast group, and a number of sites, and determines a sending time of sending the video stream to each group. The sending rate and the type of the transmitted packet, the type of the transmitted packet being at least one of the at least two packet types.

As a preferred implementation manner, this embodiment provides a specific implementation method for an AP to divide each site in a multicast group into at least two groups:

The rate of the multicast video stream is set. The receiving time of the AP receiving the multicast video stream is ^. There are W stations in the multicast group. The AP numbers each station from low to high according to the receiving rate. The receiving rate of the first station is The video stream reception time of the first station is t _a .

Define the loss cost function of the first station in the multicast group to receive the video stream: L _a = Vt - R _a t _a , the loss cost function represents the video data of the "loss" of the first station in the multicast group.

If the unicast mode is adopted, the video stream receiving time of each site is t _a AP receiving multicast video. The receiving time of the stream is t. The relationship is: t _a = t.

N

Then the total video transmission loss cost of each station in the multicast group is: L = (Vt-RjJ. If each station in the multicast group adopts unicast mode, the receiving time of receiving the multicast video stream is divided into W. For each share, the shorter time will cause the transmission loss of the multicast video stream to increase. To reduce the video loss cost, you can optimize the video stream transmission time of each station. ΑΡ The rate difference can be the first. Sites within a set range (ie, sites with similar rates, where the first setting range can be preset according to needs) are grouped into groups. Each site in the group shares a transmission time, which reduces the number of copies transmitted. , reduce the cost of loss and increase the overall throughput of the network.

The stations in the multicast group whose reception rate differs within a certain range (for example, within the first setting range) may be grouped into groups, and when the stations in the multicast group are divided into ρ groups (ρ>2), the group The sum of the cost loss of video data received by each station in the broadcast group for receiving the multicast video stream is:

L^N _x {Vt-R _x t _x ) +... + N^Vt - ·) + N _P {Vt - R _p t _p );

Wherein, the code rate of the multicast video stream is represented, t represents the sum of the transmission times of the groups in the multicast group, and represents the number of stations in the group, indicating the transmission rate of the group, t, indicating the group Delivery time;

All the grouping modes of the multicast group can be traversed, and each station in the multicast group is divided into at least two groups according to the grouping method in which the loss cost is the smallest.

Wherein, the lowest reception rate of each station in each group can be determined as the transmission rate of the group, so as to minimize the loss cost, even if the loss cost reaches the minimum value, for L^N, {Vt-R^) + ...... + N^Vt - ·) + N _P {Vt - R _p t _p ) t _P ····· t,., t _p perform optimization calculation to determine the transmission time of each group. For the optimization calculation of t _P ... t, t _p , various existing optimization algorithms can be used, and the specific algorithm adopted does not constitute a limitation of the present invention.

Since the code rate of the multicast video stream is usually changed, and the receiving rate of each station is also changed in the mobile network, the AP may periodically according to the grouping manner provided in this embodiment. Group each site in a multicast group.

5207. The AP marks the data packet type and the sending rate of the multicast video stream data packet according to the classification result of the multicast video stream data packet, and according to the sending rate of the video stream sent to each group and the type of the transmitted data packet.

After marking the data packet of the multicast video stream, the AP may send the corresponding type of data packet at the marked sending rate in the sending time of the high speed group or the low speed group.

S208: The AP sends a corresponding type of data packet on the shared channel of the multicast group at a corresponding sending rate during the sending time.

Specifically, the AP may send an important type of data packet on the shared channel of the multicast group in the transmission rate of the low-speed group during the transmission time of the low-speed group; in the transmission time of the high-speed group, the transmission rate of the high-speed group, Sending packets of important classes and sub-important classes on the shared channel of the multicast group;

Further, in order to improve the quality of the video received by the station, the AP may send the data packets of the important class and the second most important class on the shared channel of the multicast group in the transmission time of the high-speed group during the transmission time of the high-speed group. Multicast video stream packets are of high importance. They send packets of important classes first, then packets of important classes, and finally packets of non-essential classes.

In addition, when the AP sends a multicast video stream packet to each station in the multicast group, the AP sends the multicast video stream packet to the shared channel of the multicast group at a certain transmission rate, for the multicast group. For each station, the receiving rate is higher than the AP sending rate and can receive the data packets sent by the AP. Since the receiving rate of the low-speed group is lower than the high-speed group, the data packets sent by the AP in the shared channel of the multicast group can be received by the stations in the low-speed group or in the high-speed group during the transmission time of the low-speed group. Each site received. That is, each station in the high-speed group can receive the important type of data packets sent by the AP on the shared channel in the multicast group during the transmission time of the low-speed group. Therefore, as another preferred embodiment, In order to improve the utilization efficiency of the channel resources and avoid the repeated transmission of the same data packet in the air, the AP can send important types of data packets on the shared channel of the multicast group at the transmission rate of the low-speed group during the transmission time of the low-speed group. In the transmission time of the high-speed group, the AP can send only the packets of the second important class on the shared channel of the multicast group at the transmission rate of the high-speed group, and It is no longer necessary to send packets of important classes.

A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. In execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

4 is a schematic structural diagram of an embodiment of an access point according to the present invention. As shown in FIG. 4, the access point includes: a classification unit 11, a grouping unit 12, and a multicast unit 13;

The classifying unit 11 is configured to divide the multicast video stream data packet into at least two data packet types according to the importance of the received multicast video stream data packet;

The grouping unit 12 is configured to divide each station in the multicast group into at least two groups according to a code rate of the multicast video stream, a rate of each station in the multicast group, and a number of stations, and determine to send a video stream to each group. The sending time, the sending rate, and the type of the transmitted packet, the type of the transmitted packet being at least one of the at least two packet types;

The multicast unit 13 is configured to send a corresponding type of data packet on the shared channel of the multicast group at the corresponding transmission rate during the transmission time.

FIG. 5 is a schematic structural diagram of still another embodiment of an access point according to the present invention. As shown in FIG. 5, the access point includes: a classification unit 11, a grouping unit 12, and a multicast unit 13;

As a possible implementation manner, the grouping unit 12 may further include: a calculation module 121, configured to use the data = ₁ (^_^3⁄4) + ······· + N _; (Vt - ) + N _P (Vt - R _p t _p ), determining N in which the reception rate in the multicast group differs within the first set range, and the stations are grouped into groups. When the stations in the multicast group are grouped into groups, the multicast is performed. The sum of the video data loss loss costs of the multicast video stream received by each station in the group, where is the code rate of the multicast video stream, t is the sum of the transmission times of each group in the multicast group, and the number of stations in the group is represented. , indicating the transmission rate of the group, t,. indicating the transmission time of the group; The traversing module 122 is configured to traverse all the grouping modes of the multicast group, and divide each station in the multicast group into at least two groups according to a grouping manner with a minimum loss cost;

The determining module 123 determines the lowest receiving rate of each station in each group as the sending rate of the group, and performs optimization calculation on t _P ... t, t _p according to the minimum value of the loss cost, to determine the group Send time.

The multicast video stream data packet is at least divided into an important type of packet type and a sub-important type of the packet type, and each group in the multicast group is divided into groups in which the transmission rate is greater than or equal to the second set range. For the high speed group, the group whose sending rate is less than the second setting range is the low speed group, and the determining module 123 can also be used for:

It is determined that the type of packet sent to the low-speed group includes important classes, and the types of packets sent to the high-speed group include important classes and sub-important classes.

Further, the multicast unit 13 may be specifically configured to: send the important type of data packet on the shared channel of the multicast group at a transmission rate of the low-speed group during the transmission time of the low-speed group, during the transmission time of the high-speed group, Sending packets of important classes and sub-important classes on the shared channel of the multicast group at the transmission rate of the high-speed group;

Or, in the transmission time of the low-speed group, the important type of data packet is transmitted on the shared channel of the multicast group at the transmission rate of the low-speed group, and the transmission rate of the high-speed group is in the transmission rate of the high-speed group. The packets of the next important class are sent on the shared channel of the group.

As a possible implementation manner, the multicast video stream data packet is further classified into a non-critical type of data packet type. If the transmission rate of the high speed group is greater than or equal to the multicast video code rate, the multicast unit 13 may be specifically configured to: During the transmission time of the high-speed group, the types of data packets sent on the shared channel of the multicast group include important classes, sub-important classes, and non-critical classes. If the transmission rate of the high-speed group is smaller than the code rate of the multicast video stream, the multicast The unit 13 may be specifically configured to: in the transmission time of the high-speed group, the type of the data packet sent on the shared channel of the multicast group includes an important class and a second important class.

Further, the access point provided in this embodiment may further include:

a marking unit 14, configured to classify results according to the multicast video stream data packet, and according to each The sending rate of the sent video stream and the type of the transmitted packet, marking the packet type and sending rate of the multicast video stream packet.

The grouping unit 12 can be used to divide the stations in the multicast group into at least two groups according to the interval setting time.

Further, the access point provided in this embodiment may further include:

The buffer unit 15 is configured to store the received multicast video stream data packet;

The estimating unit 16 is configured to estimate the code rate of the multicast video stream according to the amount of data in the buffer unit per unit time.

Further, the multicast unit 13 may be further configured to: if the code rate of the video stream is lower than the set code rate, send the multicast video stream on the shared channel of the multicast group at the lowest receiving rate of each station in the multicast group. data pack.

The access point provided by the embodiment of the present invention is related to the video multicasting method provided by the embodiment of the present invention. To implement the function and the function of the video multicasting method, refer to the method embodiment, and no further details are provided.

The access point provided by the embodiment of the present invention classifies the data packets of the video at the access point that receives the multicast video stream, groups the sites in the multicast group, and determines the video transmission time, rate, and packet type of each group. Therefore, in the transmission time of each group, the corresponding type of data packet is transmitted on the shared channel of the multicast group according to the transmission rate of each group, thereby improving the utilization of the site resources in the multicast group and increasing the throughput of the wireless local area network. .

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently replaced. The modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

Rights request

A video multicast method, comprising:

Determining, according to the code rate of the multicast video stream, the rate of each station in the multicast group, and the number of stations, at least two groups in the multicast group, and determining to send the video stream to each group. a time, a transmission rate, and a type of the transmitted packet, the type of the transmitted packet being at least one of the at least two packet types;

The method according to claim 1, wherein the sites in the multicast group are according to a code rate of the multicast video stream, a rate of each station in the multicast group, and a number of stations. Divided into at least two groups, and determines the sending time and sending rate of the video stream sent to each group, specifically: 艮 = = ( - + · · · · · · + N _i (Vt - R _i t _i ) + N _P (Vt - R _p t _p ) , determining that the receiving rates in the multicast group are different in the first set range, and the stations are grouped into groups, and the stations in the multicast group are divided into In the ρ group, the stations in the multicast group receive the sum of the video data loss loss costs of the multicast video stream, where the code rate of the multicast video stream is represented, and t represents each of the multicast groups. The sum of the transmission times of the group, N, indicates the number of stations in the group, indicating the transmission rate of the group, t, indicating the transmission time of the group;

Traversing all the grouping manners of the multicast group, and classifying each station in the multicast group into at least two groups according to the grouping mode in which the loss cost is the smallest;

Determining the lowest reception rate of each station in each group as the transmission rate of the group, and performing optimization calculation on the t _P ... t, t _p according to the minimum value of the loss cost, to determine each group Send time.

The method according to claim 1 or 2, wherein the multicast video stream data packet is at least divided into a packet type of an important class and a packet type of a sub-important class, and the packet in the multicast group In each group divided by each station, the group whose transmission rate is greater than or equal to the second setting range is a high speed group, and the group whose transmission rate is smaller than the second setting range is a low speed group, and the data sent to the low speed group is The packet type includes the important class, and the packet type transmitted to the high speed group includes the important class and the secondary important class.

The method according to claim 3, wherein, in the sending time, the corresponding type of data packet is sent on the shared channel of the multicast group at a corresponding sending rate, specifically:

Sending, in the transmission time of the low-speed group, the data packet of the important class on the shared channel of the multicast group at a transmission rate of the low-speed group, during a transmission time of the high-speed group, Transmitting the transmission rate of the high-speed group, and transmitting the data packets of the important class and the sub-important class on the shared channel of the multicast group;

Or transmitting, in the transmission time of the low-speed group, the data packet of the important class on a shared channel of the multicast group at a sending rate of the low-speed group, during a sending time of the high-speed group, Transmitting the sub-critical class of data packets on the shared channel of the multicast group at a transmission rate of the high-speed group.

The method according to claim 4, wherein the multicast video stream data packet is further classified into a non-critical class of data packet type, if the transmission rate of the high speed group is greater than or equal to the multicast video code. Rate, the data packet type sent on the shared channel of the multicast group includes the important class, the secondary important class, and the non-essential class during a transmission time of the high speed group; If the transmission rate of the high speed group is smaller than the code rate of the multicast video stream, the data packet type sent on the shared channel of the multicast group includes the important class during the transmission time of the high speed group. And the second important class.

The method according to any one of claims 1-5, wherein, after determining the sending time, the sending rate, and the type of the data packet to be sent to each group, the method further includes:

According to the classification result of the multicast video stream data packet, and according to the video stream sent to each group The transmission rate and the type of the packet sent, marking the packet type and transmission rate of the multicast video stream packet.

The method according to any one of claims 1 to 5, characterized in that the interval setting time divides each station in the multicast group into at least two groups.

The method according to any one of claims 1 to 5, wherein the multicast video stream data packet is divided into at least two according to the importance of the received multicast video stream data packet. Before the packet type, it also includes:

And storing the received multicast video stream data packet into a local buffer unit;

The code rate of the multicast video stream is estimated according to the amount of data in the buffer unit per unit time.

The method according to claim 8, wherein after the estimating the code rate of the video stream according to the amount of data in the buffer queue per unit time, the method further includes:

And if the code rate of the multicast video stream is lower than a set code rate, sending the multicast video stream data packet on a shared channel of the multicast group at a lowest receiving rate of each station in the multicast group. .

10. An access point, comprising:

The access point according to claim 10, wherein the grouping unit comprises: a calculating module, configured to: according to L = N (Vt _ R^) + ······· + N _t (Vt - .) + N _P (Vt - R _p t _p ), determining that the reception rates in the multicast group differ by N in the first set range, and the stations are grouped into groups, and the multicast groups are When each station is divided into groups, each station in the multicast group receives the multicast video stream. The sum of the video data loss cost, wherein the code rate of the multicast video stream is represented, t represents the sum of the transmission times of the groups in the multicast group, and represents the number of stations in the group, indicating the transmission rate of the group , t, indicating the transmission time of the first group;

a traversing module, configured to traverse all the grouping manners of the multicast group, and divide each station in the multicast group into at least two groups according to the grouping method with the least loss cost;

Determining a module, determining a minimum receiving rate of each station in each group as a sending rate of the group, and performing optimization calculation on the t _P ... t, t _p according to a minimum value of the loss cost , to determine the sending time of each group.

The access point according to claim 11, wherein the multicast video stream data packet is at least divided into an important type of data packet type and a sub-important data packet type, and the multicast group is in the multicast group. In each group divided by each station, the group whose transmission rate is greater than or equal to the second setting range is a high speed group, and the group whose transmission rate is smaller than the second setting range is a low speed group, the determining module is further configured to: determine The data packet type sent by the low speed group includes the important class, and the data packet type sent to the high speed group includes the important class and the secondary important class.

The access point according to claim 12, wherein the multicast unit is specifically configured to:

The access point according to claim 13, wherein the multicast video stream data packet is further classified into a non-critical type of data packet, if the high-speed group has a transmission rate greater than or equal to the multicast group. The video code rate, the multicast unit is specifically configured to: in the sending time of the high speed group, the data packet type sent on the shared channel of the multicast group includes the important class, the time Important classes and said non-essential classes;

If the transmission rate of the high-speed group is smaller than the code rate of the multicast video stream, the multicast unit is specifically configured to: send, on a shared channel of the multicast group, in a sending time of the high-speed group The packet type includes the important class and the less important class.

The access point according to any one of claims 10 to 14, further comprising: a marking unit, configured to send a video according to the classification result of the multicast video stream data packet, and according to each group The transmission rate of the stream and the type of the packet transmitted, marking the packet type and transmission rate of the multicast video stream packet.

The access point according to any one of claims 10 to 14, wherein the grouping unit is configured to divide each station in the multicast group into at least two groups according to an interval setting time.

The access point according to any one of claims 10 to 14, further comprising: a buffer unit, configured to store the received multicast video stream data packet;

And an estimating unit, configured to estimate a code rate of the multicast video stream according to an amount of data in the buffer unit per unit time.

The access point according to claim 17, wherein the multicast unit is further configured to: if the code rate of the multicast video stream is lower than a set code rate, use the multicast group The lowest receiving rate of each station within the multicast group sends the multicast video stream data packet on the shared channel of the multicast group.