KR20110012088A - Method for managing a dynamic multicast coding in wireless network - Google Patents

Abstract

PURPOSE: A multicast coding management method using subscriber radio wave environment information in a wireless communication network is provided to perform determination and control of a MCS(Modulation and Coding Scheme) level through subscriber radio wave environment information. CONSTITUTION: A viewing terminal transmits subscriber radio wave to a server(201). By the number of terminals requesting a view in the same service zone and receiving environment of radio waves measured in the terminals, the server determines providing an initial multicast(202). The server calculates a MCS level through simulation data for maximizing radio wave efficiency of a radio section(203). Through the calculated MCS level, the server determines the MCS level about a multicast channel(204).

Description

Multicast Coding Management Method Using Subscriber Propagation Environment Information in Wireless Communication Networks {Method for Managing a Dynamic Multicast Coding in Wireless Network}

The present invention relates to a multicast coding management method for effectively transmitting a large amount of multimedia data such as mobile IPTV (Internet Protocol Television) broadcasting data in a wireless communication network. More particularly, the present invention relates to a multimedia transmission service such as mobile IPTV broadcasting in a wireless communication network. In the multicast transmission to provide, the present invention relates to a multicast coding management method for minimizing radio resource consumption by determining and controlling a modulation and coding scheme (MCS) level using subscriber propagation environment information.

In the following embodiment, a mobile Internet (also called "WiBro network" or "mobile WiMAX") is described as an example of a wireless communication network, but the present invention is not limited thereto.

In a conventional mobile communication network or a mobile Internet, a broadcast stream is transmitted in a unicast manner for each subscriber station or after a worst-case radio wave environment condition, a broadcast stream is transmitted in a network through a multicast scheme. That is, in the conventional multicast scheme, a broadcast stream is unconditionally transmitted regardless of the presence or absence of a viewing subscriber (terminal) and the number of subscribers (terminals).

In the conventional method of providing a broadcast stream using unicast, since a radio resource for each subscriber station is allocated for high-bandwidth traffic in a mobile communication network or a mobile Internet having a poor radio resource bandwidth compared to a wired environment, There was a disadvantage of not accepting subscribers, and high cost was required for the use of radio bandwidth.

Meanwhile, as another method, a method of transmitting a broadcast stream in a multicast or broadcast manner by using one radio resource channel in common and a plurality of terminals jointly using the radio resource channel have been proposed. . However, such a method also has a problem in that wireless bandwidth resources of the third generation mobile communication network or the portable Internet are insufficient to require continuous broadcasting based on a plurality of channels.

In the case of the wireless Internet, since the ability of extracting the received signal varies depending on how far the subscriber station is from the base station, the coding scheme is applied differently. Moreover, in order to provide an equivalent service to all subscribers, the cell boundary is the worst case. This is because the coding method is applied centering on the weak electric field such as the area, so it uses more radio resources than the actual transmission data.

In other words, when transmitting a mobile IPTV broadcast stream in a conventional mobile communication network or a mobile Internet, the wireless bandwidth is excessively transmitted to transmit the same information by fixedly setting the MCS level in consideration of the harsh environment at the cell boundary to cover the entire base station. There is a problem that is occupied, and thus it is impossible to provide a multimedia service to a plurality of terminals because the number of terminals and service channels that are serviced in one base station is limited. For this reason, the cost of using video services such as VoD (Video on Demand) in mobile communication networks has become high.

In other words, in providing a mobile IPTV broadcast in the existing mobile communication network or the portable Internet, when using unicast for individual viewers, the transmission band increases by the number of viewing terminals, and even when using multicast Regardless of the presence of the viewing terminal, the use of a low efficiency MCS level consumes 4 to 6 times more radio resources than transmission in an efficient environment.

Therefore, the prior art as described above, there is a problem that the radio resources in the base station is excessively wasted by unconditionally transmitting the mobile IPTV broadcast stream irrespective of the existence of the service target terminal, it is an object of the present invention to solve this problem.

Accordingly, an object of the present invention is to provide a multicast coding management method for minimizing radio resource consumption by determining and controlling a modulation and coding scheme (MCS) level using subscriber propagation environment information.

That is, the present invention does not waste the radio resources in the base station by unconditionally transmitting the mobile IPTV broadcast stream irrespective of the existence of the service target terminal, but considers the presence of a subscriber in the base station or service area and the radio wave reception environment of the terminals. By actively determining and controlling the MCS level, an object of the present invention is to provide a multicast coding management method for minimizing radio resource consumption.

In other words, the present invention is to reduce the number of broadcast channels to be delivered and general Internet traffic by simply managing radio resources based on the weak electric field with poor radio wave transmission in transmitting multicast mobile IPTV broadcasts on the portable Internet. In addition, by actively changing the MCS level of the multicast channel (multicast broadcast channel) in consideration of the number and location of the terminals that are requested to view, a multicast coding management method for providing an optimal mobile broadcast channel environment is provided. There is a purpose.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned above can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

According to an aspect of the present invention, there is provided a multicast coding management method, comprising: a receiving step of receiving subscriber propagation environment information from a terminal side; Determining whether to provide a multicast using the received subscriber propagation environment information; Calculating an MCS level for maximizing propagation efficiency of a radio section; And an MCS level determining step of determining an MCS level for a multicast channel using the calculated MCS level.

In addition, the method of the present invention further includes the step of delivering the multicast providing information and MCS configuration criteria information to the terminal to provide a service according to the MCS level determined in the MCS level determination step.

The method may further include resetting the MCS level according to the MCS level criterion exceeded information from the terminal while providing the service by determining the MCS level in the MCS level determining step.

The method may further include transmitting the packet in a unicast manner according to a request for retransmission of a lost packet from the terminal.

The method may further include switching from a multicast scheme to a unicast scheme and providing a service as the packet loss amount at the terminal exceeds a threshold.

As described above, the present invention analyzes the distribution in the service area (multicast zone) or the base station (RAS) of the viewer terminal and the radio wave reception environment of the viewer terminal to actively determine and assign the multicast broadcast channel, and assigns the multicast broadcast channel. By controlling the MCS level for the appropriate level, it is possible to use the radio resources efficiently, thereby providing a multimedia transmission service such as mobile IPTV broadcast to more viewer terminals.

At this time, the process of determining the MCS level collects the subscriber propagation environment information such as the radio wave reception state of the terminal when requesting viewing, the change of the radio wave reception environment value at the actual terminal compared to the MCS level set during viewing, and the loss of received traffic. To change the MCS level. To this end, the terminal measures its radio wave reception status and actual traffic reception status and transmits it to the server side, and the server platform determines and controls the MCS level based on radio wave environment information from the terminal side.

As described above, the present invention has the effect of minimizing radio resource consumption by determining and controlling the modulation and coding scheme (MCS) level using subscriber propagation environment information.

In addition, the present invention, when providing a mobile IPTV broadcast service through a multicast to a plurality of viewers in a wireless communication network, irrespective of the existence of the service target terminal to transmit the mobile IPTV broadcast stream unconditionally to waste radio resources in the base station In order to reduce unnecessary waste of radio resources by actively changing the MCS level in consideration of the presence of a subscriber in the base station or service area and the radio wave reception environment of the terminals, the surplus radio resources may be added to other broadcasting channels. As it can be used as a general Internet, it is possible to realize a large capacity multimedia transmission service such as mobile IPTV broadcasting by utilizing resources in a limited wireless communication network.

That is, the present invention does not reduce the number of broadcast channels to be delivered and general Internet traffic by simply managing radio resources based on a weak electric field with poor radio wave transmission in transmitting multicast mobile IPTV broadcasts on a portable Internet. By actively changing the MCS level of the multicast broadcast channel in consideration of the number and location of terminals that are requested to view, it is possible to reduce the overall consumption band compared to the fixed multicast service and to provide an optimal mobile broadcast channel environment. can do.

In addition, when the mobile IPTV broadcast is to be received through the portable Internet, the present invention transmits the terminal information along with the radio wave environment information of the terminal to the server in the case of periodic or deviation of the reference value even while the service is in use. It can be utilized whether the permission is allowed, and the quality of service of the terminal.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It can be easily carried out. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the technical gist of the present invention will be described in order to help the understanding of the present invention.

In a wireless communication network such as the mobile Internet, a multicast group is created according to the number of users connected to a multicast zone (service area) and a radio wave environment of a user terminal for multimedia transmission such as mobile IPTV broadcasting. Analyze this to determine the Modulation and Coding Scheme (MCS) level.

In this case, the reason for considering the number of users connected to the service area and the propagation environment of the user terminal is that when the number of users located in the service area such as RAS (Radio Access Station) is small, multicast is provided based on cell boundary area. This is because providing a service by unicast based on individual terminals can consume less radio resources.

In addition, even when delivering a mobile IPTV broadcast stream by multicast, delivering based on 64QAM set based on a strong electric field is higher transmission gain than coding and delivering at QPSK level in a situation where radio waves are poor. 4 to 6 times or more), it is possible to efficiently control the multimedia transmission by measuring the radio wave reception environment of the service user terminal and actively setting the MCS level of the multicast broadcast channel.

Looking at how to implement this effectively, it can be summarized as follows.

First, MCS coding criteria setting method according to distribution of user terminal by service channel

Second, using MCS level after using multiple coding for the same service channel

Third, the method of changing the MCS coding level by analyzing the propagation environment of the user terminal

Looking at the structure of each process, the distribution of the viewing request terminal and the viewing request terminal prior to the process of configuring a multicast broadcast channel for individual broadcasts, and setting a multicast channel ID (MCID) for multicast transmission in the portable Internet Collect the radio wave reception of the to determine the MCS level for the multicast broadcast channel.

After the process of transmitting the broadcast stream by determining the MCS mode for the initial multicast, information on the broadcast stream reception status and the reception end of the viewing terminal is received to determine the expansion and reduction of the multicast region. The main decision index may be the number of terminals watching the broadcast, the distribution of the radio wave reception environment of the terminal, the error status of the fed-back viewing terminal, and the number of broadcasting viewers at the present time reflecting the number of subscribers ending the broadcast. The quality of service can be improved by minimizing resource consumption and using the spare band accordingly.

In the process of requesting service viewing at the first terminal, the server side determines whether the MCS level should be changed according to the existence of the broadcast in the requested service area of the corresponding broadcast and the propagation environment of the new service requesting terminal. The information is transmitted to the service request terminal so that the broadcast can be viewed. After the multicast transmission, if the UE is exposed to an environment that cannot accept the received reference MCS level, the UE performs a procedure of transmitting its propagation environment information to the server in order to request the MCS level change of the broadcast channel. Then, the server end determines whether it is efficient to change the MCS level value for the corresponding service or excludes the terminal from the multicast group, and transmits the change information to the corresponding service terminal.

The present invention, unlike the conventional method of transmitting a broadcast stream fixedly irrespective of the subscriber in the radio section, provides a high-definition service for the high-band transport stream for service users in the range of more than 85% center of the base station in step of the radio wave strength In addition, by transmitting a low-band encoded broadcast stream at the request of a viewer based on a weak electric field at a cell boundary, a large number of viewers (compared to the conventional method of transmitting all services at the same coding level based on the weak electric field) It is effective in providing high quality service to users but using less radio resources.

In addition, in the terminal that is difficult to drive a high-quality service due to the performance constraints of the terminal, the low-band service set based on the weak electric field can be provided in the entire service area, thereby improving the scope and quality of service provision. For example, comparing the case of transmitting a broadcast stream using QPSK1 / 2 centered on a weak electric field and the case of transmitting a broadcast stream of the same quality through 64QAM, the actual radio resources consumed in the mobile Internet are QPSK1 / 2. This is more than four times higher than 64QAM. That is, it is better to transmit a 500Kbps-class broadcast stream at 64QAM rather than to transmit a 500Kbps broadcast stream at QPSK1 / 2. Therefore, if you provide broadcasting streams at 250Kbps in QPSK1 / 2 and 1Mbps in 64QAM at the same time, you can provide high-quality services to most terminals in the strong electric field compared to transmitting broadcast streams only at 500Kbps in QPSK1 / 2. Minimal service can be provided to the edge subscriber station and the low specification terminal, thereby providing an environment in which radio resources can be efficiently used.

1 is a diagram illustrating an embodiment of a server and a terminal in a wireless communication network to which the present invention is applied.

As shown in FIG. 1, in a wireless communication network to which the present invention is applied, the terminal module 110 may include a broadcast stream data reproducing unit 111 for reproducing broadcast stream data received from a server side, and a server in a multicast manner. Multicast reception traffic quality measurement unit 112 for measuring the quality of the traffic received from the side, terminal propagation environment measurement and MCS level management unit for measuring the radio wave environment of the viewing terminal, and managing the MCS level from the server side ( 113), and the radio wave environment information transmitter 114 for periodically transmitting the radio wave environment information of the terminal (the number of requesting terminal, the radio wave reception strength, the entry / departure of the viewer terminal, the multicast reception failure rate, etc.) to the server periodically. It includes.

In the wireless communication network to which the present invention is applied, the server-side module 120 transmits whether the multicast is provided and the MCS setting reference value to the terminal, and is informed of the occurrence of excess MCS criteria, excessive packet loss, etc., from the terminal. Performs a function of receiving and managing departure / entry information of the subscriber terminal.

As described above, the terminal to which the present invention is applied manages the MCS level provided when watching a multicast IPTV broadcast, and if it is out of the reference range, it is possible to determine whether to change the MCS level by providing the MCS level exceeding information to the server side. Even if the MCS level is within the reference range, if the error state (multicast reception failure rate) for the received multicast data is monitored and the value is above a certain level, the MCS level value for the multicast is changed or the terminal is presently present. Multicast is being applied so that a change from scheme to unicast can be requested.

As such, by analyzing the MCS level received from the terminal and transferring the MCS criterion exceeded information to the server when it is out of the reference range, an analysis of the radio wave reception environment of the terminal, which is one of the important factors as a criterion on the server side, is performed. In order to make the data current, the amount of data received from the terminal side can be reduced.

2 is a flowchart illustrating a multicast coding management method using a subscriber propagation environment in a wireless communication network according to an embodiment of the present invention, and collects and analyzes terminal information managed for each service zone for a specific multicast broadcast channel, thereby providing an MCS level. The criteria and process for determining this are shown.

As shown in FIG. 2, the viewing terminal includes the number of viewing request terminals in the service zone, the radio wave strength (radio wave receiving environment) of the viewing terminal, the entry / departure within the service zone of the viewing terminal, and the multicast reception failure rate of the viewing terminal. The subscriber propagation environment information is transmitted to the server side (201).

Then, the server side determines whether to provide initial multicast based on the number of terminals requesting viewing in the same service zone, which is one of important information for transmitting a broadcast stream in a multicast manner, and the radio wave reception environment measured by these terminals. (202).

On the server side, the MCS level is calculated through simulation data for maximizing the propagation efficiency of the wireless section (203).

For example, in case of services for terminals located in strong electric field and heavy electric field with good radio wave environment, MCS level is applied based on 64QAM or 16QAM standard used in mobile Internet, and service area is set up to weak electric field with poor radio wave environment. The use of radio waves can be controlled by applying MCS levels based on QPSK.

Then, the MCS level for the multicast channel is determined using the calculated MCS level to provide a service (204).

After the above process, it is determined whether to continue multicast and change the MCS level based on the number of new entry and exit services for the corresponding multicast channel (multicast broadcast channel), the multicast reception failure rate of service viewing terminals (MCS level re-determination). To provide services.

3 is a diagram illustrating a multicast coding management method using a subscriber propagation environment and a multicast / unicast switching process according to the present invention.

As shown in FIG. 3, the terminal requesting the service is verified through the service authentication center 301 for the authority to allow the broadcast access (viewing authority authentication), and the multicast transmission MCS management server 302 is viewing authority authentication. Based on the information, the service request of the terminal and the radio wave environment information of the terminal are received to determine whether to provide multicast.

When this process is successfully determined and a service is provided through multicast streaming, the multicast streaming transmission server 303 transmits content or broadcast streaming data from a content provider (CP) to a corresponding service zone in a multicast manner. .

Accordingly, the terminal receives and reproduces the multicast broadcast stream, requests retransmission to the unicast switch server 304 for packet loss, etc. generated during the multicast reception process, and the unicast switch server 304 sends the lost packet. Retransmit to the terminal.

In addition, when the packet loss amount is increased to a predetermined level or more during the transmission process, when the multicast transmission to the corresponding terminal is inappropriate, the unicast switching server 304 switches from the multicast transmission to the unicast transmission and provides a service. .

In this case, only the multicast transmission may provide a service in a multicast environment that is vulnerable to flow control and transmission errors, and can cope with some errors through the unicast switching server 304.

4 is a diagram illustrating an example of setting an MCS level according to a radio wave strength in a service area (multicast zone) according to the present invention.

As shown in FIG. 4, in the service for a terminal located in a strong electric field and a medium electric field having a good radio wave environment, an MCS level is applied based on 64QAM or 16QAM used in the mobile Internet, and a service area up to a weak electric field having a bad radio wave environment. If you set, you can adjust the use of radio waves by applying the MCS level based on QPSK.

Compared to the existing method of setting the weak electric field based on the weak electric field regardless of the existence of the subscriber and the distribution of the terminal, the present invention can generate a large part of the propagation gain based on the subscriber over the medium electric field range in which the majority of the subscribers are distributed. It actively changes the target coverage of service transmission to proactively cope with the entry and departure of service viewing terminals, and utilizes the remaining free band for accommodating other broadcasting channels or allocates it to general Internet traffic transmission to efficiently use limited radio resources. Can be used.

On the other hand, the method of the present invention as described above can be written in a computer program. And the code and code segments constituting the program can be easily inferred by a computer programmer in the art. In addition, the written program is stored in a computer-readable recording medium (information storage medium), and read and executed by a computer to implement the method of the present invention. The recording medium may include any type of computer readable recording medium.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention can be used to transmit large-capacity multimedia data using a wireless communication network, that is, mobile IPTV transmission using a portable Internet.

1 is a view illustrating an embodiment of a server and a terminal in a wireless communication network to which the present invention is applied;

2 is a flowchart illustrating a multicast coding management method using a subscriber propagation environment in a wireless communication network according to the present invention;

3 is a view illustrating a multicast coding management method using a subscriber propagation environment in a portable Internet according to the present invention and a multicast / unicast switching process according to the present invention;

4 is a diagram illustrating an example of setting an MCS level according to a radio wave strength in a service area (multicast zone) according to the present invention.

* Explanation of symbols for the main parts of the drawings

301: Service Certification Center

302: multicast transmission MCS management server

303: multicast streaming transmission server

304: unicast switch server

Claims (6)

In the multicast coding management method, A receiving step of receiving subscriber propagation environment information from a terminal side; Determining whether to provide a multicast using the received subscriber propagation environment information; Calculating an MCS level for maximizing propagation efficiency of a radio section; And MCS level determination step of determining the MCS level for a multicast channel using the calculated MCS level Multicast coding management method comprising a. The method of claim 1, Delivering multicast provision information and MCS configuration reference information to the terminal in order to provide a service according to the MCS level determined in the MCS level determination step; Multicast coding management method further comprising. The method according to claim 1 or 2, Resetting an MCS level according to MCS level criterion exceeded information from the terminal while providing a service by determining an MCS level in the MCS level determination step; Multicast coding management method further comprising. The method of claim 3, wherein Transmitting the packet in a unicast manner according to a request for retransmission of a lost packet from the terminal. Multicast coding management method further comprising. The method of claim 3, wherein Providing a service by switching from a multicast scheme to a unicast scheme as a packet loss amount in the terminal exceeds a threshold; Multicast coding management method further comprising. The method of claim 5, The subscriber propagation environment information, And at least one of the number of the viewing request terminals in the service area, the radio wave reception strength of the terminal, the entry / departure in the service area of the terminal, and the multicast reception failure rate of the terminal.

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