KR100889864B1 - Method and system for compression transmission of multimedia data - Google Patents

Abstract

The present invention relates to a method and a system for compressing and transmitting multimedia data in UMTS. In particular, in a system for compressing multimedia data and broadcasting or multicasting it in downlink, a transmitting side is failed when a plurality of terminals do not form a full context. If the UTRAN is quickly transitioned to the full context formation state and fails to form the dynamic context, the UTRAN is quickly transitioned to the dynamic context formation state, so that a large number of terminals normally convert the header-compressed MBMS data into the U-mode of the ROHC technique. It is an object of the present invention to provide a system and method for compressing and transmitting multimedia data to increase the transmission efficiency by transmitting the packet, which is transmitted from the UTRAN in the RRC layer of the terminal, to the header compression responsible layer of the terminal. If no context can be formed therefrom, the UTRAN on the sending side Context information is transmitted to the RRC layer using an RRC message, and the contextual damage information received from the terminal is accumulated in the RRC layer of the UTRAN according to the type of the context formation state, and then the RRC layer or the header compression responsible layer of the UTRAN. If the number of contextual damage information is greater than or equal to a predetermined threshold, the header compression responsible layer transitions back to the previous contextual or dynamic context formation state. By transmitting a packet for context formation.

Description

METHOD AND SYSTEM FOR COMPRESSING AND TRANSMITTING MULTIMEDIA DATA}

1 is a block diagram of a general UMTS network.

2 is a structural diagram of a radio access interface protocol between a terminal and a UTRAN based on the 3GPP radio access network standard;

Figure 3 is a state diagram showing the state and transition of the compressor of the typical ROHC U-mode.

4 is an exemplary view showing the point-to-many characteristics of a typical MBMS.

5 is a flowchart illustrating a U-mode operation of a general conventional ROHC technique.

6 is a block diagram showing the configuration of a system for compression transmission of MBMS data using the ROHC technique in an embodiment of the present invention.

7 is a flowchart illustrating a process of compressing and transmitting MBMS data using an ROHC technique in an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

610: terminal 611, 621: radio resource control (RRC) layer

620: UTRAN 612,622: header compression layer

The present invention relates to a data compression transmission method in a wireless mobile communication system, and more particularly, to a compression transmission method and system for multimedia data in a universal mobile telecommunications system (UMTS).

Wireless mobile communications have made great strides, and wireless mobile phones have become more popular than landline phones. However, in the service of providing a large amount of data communication beyond the general voice call to the wireless mobile phone through the wireless access network, the wireless mobile communication has not yet been able to keep up with the performance of the existing wired communication system. Therefore, a communication system that enables such a large amount of data communication is called IMT-2000, and technology development is promoted in various countries around the world, and cooperation between countries is progressing in standardization.

Universal Mobile Telecommunications System (UMTS), a European-style IMT-2000 system, is a third generation mobile communication system that evolved from the European standard Global System for Mobile Communications (GSM) system.The GSM Core Network and the Wideband Code Division Multiplex Access) It aims to provide better mobile communication service based on access technology.

In December 1998, for the standardization of UMTS, ETSI in Europe, ARIB / TTC in Japan, T1 in the US, and TTA in Korea were referred to as the Third Generation Partnership Project (hereinafter abbreviated as 3GPP). So far, a detailed specification of UMTS is being prepared.

In 3GPP, UMTS standardization work is divided into 5 Technical Specification Groups (hereinafter abbreviated as TSG) in consideration of the independence of network components and their operation for the rapid and efficient technology development of UMTS. Doing.

Each TSG is responsible for the development, approval, and management of standards within the relevant areas, among which the Radio Access Network (hereinafter referred to as RAN) group (TSG RAN) supports WCDMA access technology in UMTS. Develops specifications for the functions, requirements and interfaces of the UMTS Terrestrial Radio Access Network (hereinafter referred to as UTRAN).

1 is a block diagram of a general UMTS network.

As shown in FIG. 1, the UMTS system is largely composed of a terminal, a UTRAN 100, and a core network 200.

The UTRAN 100 is composed of one or more Radio Network Sub-systems (RNS) 110, 120.

The wireless network system 110, 120 is a radio network controller (hereinafter referred to as RNC) 111, and one or more Node B (112) (113) managed by the RNC (111) It is composed.

The RNC 111 is responsible for allocating and managing radio resources and serves as an access point with the core network 200.

The Node Bs 112 and 113 serve as access points of the UTRAN 100 to the terminal by receiving information transmitted from the physical layer of the terminal in uplink and transmitting data to the terminal in downlink. do.

The core network 200 includes a Mobile Switching Center (MSC) 210, a Gateway Mobile Switching Center (GMSC) 220 for supporting a circuit switched service, and a Serving GPRS Support Node (SGSN) for supporting a packet switched service ( 230, a Gateway GPRS Support Node (GGSN) 240 is provided.

The services provided to specific terminals are largely divided into circuit-switched services and packet-switched services. For example, general voice telephone services belong to circuit-switched services, and web browsing services through Internet access are classified as packet-switched services.

First, in case of supporting circuit switched service, the RNC 111 is connected with the MSC 210 of the core network 200, and the MSC 210 is connected with the GMSC 220 managing the incoming or outgoing connection from another network. .

For the packet switched service, the service is provided by the SGSN 230 and the GGSN 240 of the core network 200. The SGSN 230 supports packet communication destined for the RNC 111, and the GGSN 240 manages connection to another packet switching network such as the Internet network.

There is an interface (Interface) that can send and receive information for communication between the various network components, the interface between the RNC 111 and the core network 200 is defined as the Iu interface.                         

When the Iu interface is connected to the packet switched area, it is defined as 'Iu-PS'. When the Iu interface is connected to the circuit switched area, it is defined as 'Iu-CS'.

2 illustrates a structure of a radio access interface protocol between a terminal and the UTRAN 100 based on the 3GPP radio access network standard.

The wireless access interface protocol of FIG. 2 consists of a physical layer, a data link layer, and a network layer horizontally, and vertically, a control plane for transmitting a user plane and a signaling signal for transmitting data information. Control Plane).

The user plane is an area in which traffic information of the user is transmitted, such as voice or IP packet transmission, and the control plane is an area in which control information is transmitted, such as network interface or call maintenance and management.

The protocol layers of FIG. 2 are based on the lower three layers of the Open System Interface (OSI) reference model, which are well known in communication systems, and include L1 (first layer), L2 (second layer), and L3 (first layer). Three layers).

Hereinafter, each layer of FIG. 2 will be described.

The L1 layer, that is, the physical layer, provides an information transfer service to an upper layer by using various wireless transmission technologies. The physical layer is connected to a higher layer by a medium access control layer through a transport channel. Data is transferred between the medium access control layer and the physical layer which is the L1 layer in the transport channel.                         

The L2 layer includes a medium access control layer (hereinafter referred to as MAC) layer, a radio link control layer (hereinafter referred to as RLC) layer, a packet data convergence protocol (hereinafter referred to as PDCP). There is a hierarchy.

The MAC layer provides a reassignment service of MAC parameters for allocating and reallocating radio resources, and is connected to an RLC layer, which is a higher layer, by a logical channel. Various logical channels are provided according to the type of information to be transmitted. Generally, a control channel is used for transmitting control plane information, and a traffic channel is used for transmitting user plane information. use.

The RLC layer supports reliable data transmission and performs a segmentation and concatenation function of an RLC service data unit (hereinafter, abbreviated as SDU) from an upper layer. The RLC SDU delivered from the upper layer is sized according to the processing capacity in the RLC layer, and then header information is added to the MAC layer in the form of a protocol data unit (hereinafter, abbreviated as PDU). In the RLC layer, there is an RLC buffer for storing RLC SDUs or RLC PDUs from above.

The PDCP layer is located above the RLC layer and allows data transmitted through a network protocol such as IPv4 or IPv6 to be efficiently transmitted over a relatively small bandwidth wireless interface. To this end, the PDCP layer performs a function to reduce unnecessary control information used in a wired network. Such a function is called header compression. The header compression technique may use RFC2507 and RFC3095 (Robust Header Compression: ROHC) defined by the Internet Standardization Group called the Internet Engineering Task Force (IETF). These methods transmit less control information by transmitting only necessary information in the header part of the data, thereby reducing the amount of data to be transmitted.

The broadcast / multicast control layer (hereinafter abbreviated as BMC) layer schedules a cell broadcast message (hereinafter abbreviated as CB message) transmitted from a core network, and transmits the cell broadcast message to a specific cell. Thus, all terminals located in the cell perform the cell broadcast message. In particular, the BMC layer is used only for the broadcasting function, and the CB message is a short message composed of up to '1230' octets consisting of letters and numbers only between terminals or between a terminal and a system.

In terms of UTRAN, the CB message transmitted from the upper layer is added to the RLC layer in the form of a BMC message by adding information such as message ID, serial number, and coding scheme. The BMC message is delivered to the MAC layer through a common traffic channel (CTCH) logical channel, where the CTCH logical channel is mapped to a forward access channel (FACH) transport channel, and the FACH transport channel is a SCCPCH (Secondary Common Control Physical Channel). Mapped to physical channel.

At the bottom of the L3 layer is a Radio Resource Control (hereinafter, referred to as RRC) layer.                         

The RRC layer is defined only in the control plane and is responsible for controlling transport channels and physical channels in connection with setting, resetting, and releasing radio bearers. The radio carrier refers to a service provided by the second layer for data transmission between the terminal and the UTRAN. In general, the radio carrier is configured to define characteristics of protocol layers and channels required to provide a specific service, and It means the process of setting specific parameters and operation methods.

For reference, the RLC layer may belong to a user plane or a control plane according to a layer connected to an upper layer. In case of belonging to the control plane, data is transmitted from the RRC layer, and in other cases, it is a user plane.

In addition, as shown in FIG. 2, in the case of the RLC layer and the PDCP layer, several entities may exist in one layer. This is generally because one terminal has several radio carriers and only one RLC entity and PDCP entity are used for one radio carrier.

Hereinafter, a Robust Header Compression (ROHC) header compression method used for header compression in the PDCP layer will be described.

The ROHC compressor method is generally used to reduce header information of a Real-time Transport Protocol (RTP) / User Datagram Protocol (UDP) / Internet Protocol (IP) packet. In this case, the RTP / UDP / IP packet refers to a packet in which data from the upper layer passes through RTP, UDP, and IP, and has associated headers attached thereto, and various header information necessary for data to be transmitted and restored to the destination through the Internet. It includes.                         

The ROHC compressor method is based on the fact that a field value of each packet header is substantially constant in consecutive packets belonging to one packet stream. Therefore, the ROHC compressor method does not transmit the entire packet header field but transmits a variable field.

For reference, the total header size of the uncompressed RTP / UDP / IP packet is '40' octets for IPv4 (IP version 4) and '60' octets for IPv6 (IP version 6), whereas The size of a pure data portion called a payload is typically '15 -20 'octets. From this, it can be seen that the transmission efficiency is very low because the control information included in the data transmission is much larger than the actual data to be transmitted. Therefore, if the header compression technique is used, the amount of control information can be greatly reduced. In the case of using the ROHC header compression scheme, the reduced header size is usually only about '1' to '3' octets.

ROHC compressor method is largely divided into Uni-directional mode (hereinafter referred to as U-mode), Bi-directional Optimistic mode (hereinafter referred to as O-mode) and Bi-directional Reliable (hereinafter referred to as R-mode). It is divided into three modes.

The U-mode transmits one-way communication from the transmitting side to the receiving side, and the O-mode or R-mode transmits real time packets from the transmitting side, and transmits transmission status information from the receiving side to the transmitting side. Accordingly, the ROHC compressor method of the O-mode and R-mode controls not only the transmission of the header compression packet of data but also the ROHC status information (ACK or NACK) from the receiving side to control the reverse transmission of the real-time traffic packet.

The ROHC status information transmitted from the receiver side to the transmitter side may be used for different purposes.In O-mode, NACK-related information is mainly sent to increase the compression efficiency, and the R-mode uses strict logic using ROHC status information. ) To support more robust header compression techniques.

Looking at the U-mode of the ROHC compressor method in more detail, the compressor has three states of the full context, the dynamic context and the full context, the type of compression header packet that can be transmitted for each state In addition, the operation method is also different and consists of static and dynamic contexts.

Each state of the U-mode can be seen in Figure 3, the entire context formed state means that the entire context is not formed at all, or the entire context is completely damaged and must be configured again. In addition, the dynamic context formation state refers to a state in which the dynamic context part of the entire context is damaged and reconfigured, and the entire context perfect state means the entire context is intact.

Each state is timed out for each period and transitions to another state, and each period is different. For example, the transition period from the full context complete state to the full context formation state is much greater than the transition period from the full context complete state to the dynamic context configuration state.

Next, a multimedia broadcast / multicast service (hereinafter, abbreviated as MBMS) will be described.

MBMS does not support the multicast function of the cell broadcast service (hereinafter abbreviated as CBS) provided by the existing BMC layer, and the size of a short message that can be transmitted is limited to '1230' octets. The proposed service is limited in providing multimedia services.

In addition, as shown in FIG. 4, the MBMS is a service that simultaneously delivers multimedia data such as audio, pictures, and video to a plurality of terminals using a unidirectional point to multipoint bearer service. ) And multicast mode. That is, it supports MBMS broadcasting service and MBMS multicast service.

First of all, the broadcasting mode of MBMS is a service for transmitting multimedia data to all users in a broadcast area. One or more broadcasting areas may exist in one PLMN, and one or more broadcasting services may be provided in one broadcasting area. It may be provided, and one broadcast service may be provided to multiple broadcast areas.

Here, the broadcasting area means an area where a broadcasting service is available.

In addition, the multicast mode of MBMS is a service for transmitting multimedia data only to a specific user group in a multicast area. In one PLMN, more than one multicast area may exist, and in one multicast area. One or more multicast services may be provided, and one multicast service may be provided in multiple multicast regions.

Here, the multicast zone refers to an area where multicast service is possible.

As such, MBMS is a service that transmits multimedia through broadcasting or multicasting. Since the packet size is quite large, the header part compresses the header portion, which occupies a large part of the packet, to increase data transmission efficiency. In this case, ROHC is used as a header compression technique for the MBMS service.

However, since MBMS cannot receive ROHC status information as a unidirectional point-to-multipoint service, only U-mode is available among the three modes of ROHC, and U-mode can be used only for unidirectional transmission, as shown in FIG. The terminal, which is the receiver of the MBMS, successfully receives the entire header packet and transmits the packet in each state regardless of whether the context is normally formed or the dynamic context is damaged.

In other words, MBMS compresses the header part of multimedia data into '1 to 2' octets using the ROHC compressor method to improve the data transmission efficiency. However, only U-mode of ROHC is available because of the one-way service. Actually, since U-mode is a method for header compression on a point-to-point link, there is a problem in that it is applied to a point-to-multipoint link as in MBMS.

The problem of operation in point-to-multilink of U-mode is described in more detail.

For example, when UTRAN, which is a transmitting party, simultaneously compresses multimedia data to broadcast and multicast to multiple terminals that want to receive a service, the type of header packet transmitted is total header packet or dynamic context forming packet. If the packet is received, the receiving side forms a full context or a dynamic context. In this case, if the context is successfully formed, the compressed header packet to be transmitted can be restored successfully. Compressed header packets are not recoverable. That is, the terminals cannot receive the MBMS service.

Therefore, conventionally, when the terminals fail to form the entire context or the dynamic context by receiving the entire header packet or the dynamic context-forming packet as described above, the entire context is in the dynamic context, or the entire context in the complete context In the event of a transition to the context-forming state, that is, a timeout and a wait until a new operation is started in the context-forming state, terminals which fail to form a context cannot receive MBMS service for a considerable period of time. As a result, a problem arises in the utility of the service.

As described above, when attempting to compress MBMS data having a point-to-multipoint characteristic by using the U-mode of the ROHC technique, which is a header compression method in a point-to-point link, a plurality of terminals are used to compress the entire context. If it fails to form, there is a problem that the header-compressed MBMS data cannot be continuously received until the UTRAN, which is the transmitting side, transitions to the full context forming state, or fails to form the dynamic context.

Therefore, the present invention has been created to improve the conventional problems as described above, and when a plurality of terminals fail to form a full context, the UTRAN as a transmitting side quickly transitions to a full context forming state and forms a dynamic context. In case of failure, the UTRAN transitions to the dynamic context forming state so that a large number of terminals can normally receive the header compressed MBMS data in the U-mode of the ROHC method, thereby increasing the transmission efficiency. It is an object to provide a system and method.
In order to achieve the above object, the present invention provides a UTRAN for compressing and transmitting MBMS data using the U-mode of the ROHC scheme according to the type of context forming state, and forms a corresponding context from a received packet, And a terminal for transmitting the contextual damage information to the UTRAN which is the transmitting side.
The UTRAN accumulates the number of total contextual damage information and the number of dynamic contextual damage information transmitted from the terminal through the RRC layer, and the predetermined number of the respective contextual damage information accumulated through the RRC layer or the header compression responsible layer. It is configured to compare and determine whether greater than or equal to the threshold value of.
The RRC layer or the header compression responsible layer compares the number of contextual damage information with a threshold value, and when the number of contextual damage information is greater than or equal to a predetermined threshold value, the header compression responsible layer corresponds to the previous one. Characterized in that it can be configured to quickly transition to the context-forming state.
If the UE is not successful in forming the context, the context damage information according to the type is transmitted to the RRC message from the RRC layer of the terminal to the RRC layer of the UTRAN of the transmitting side.
In addition, the present invention for achieving the above object accumulates the number of contextual damage information when the context is not successful in the receiving side, and whether the cumulative amount of the contextual damage information is greater than or equal to a predetermined threshold value; Whether it is greater than or equal to the threshold value, it quickly transitions to the previous contextual state.
Therefore, in the present invention, when the MBMS data is compressed and transmitted using the U-mode of the ROHC technique, if the receiver terminal fails to form the entire context with the entire header packet, that is, if the entire context is damaged, the entire context is damaged. Information is transmitted to the UTRAN, which is the transmitting side, and the UTRAN causes the compressor of the header compression responsible layer when the number of total contextual damage information transmitted from the receiving side becomes larger than a threshold value for the predetermined total contextual damage information. It is characterized in that the state transition to the full context formation state, by transmitting the full header packet, to form the full context as soon as possible to allow the terminal to receive the MBMS service.
In addition, if the receiving terminal fails to form the dynamic context with the dynamic context forming packet, that is, the dynamic context is damaged, the dynamic context damage information is transmitted to the transmitting side, UTRAN, and the UTRAN transmits the dynamic context damage transmitted from the receiving side. When the number of information becomes larger than the threshold value for the dynamic context damage information, the compressor of the header compression layer makes the state transition to the dynamic context formation state and transmits the dynamic context formation packet. By forming a dynamic context as soon as possible characterized in that the terminal receives the MBMS service.

The present invention is applied to wireless mobile communication. However, the present invention is not limited thereto and may be applied to all wired and wireless communication to which the technical spirit of the present invention can be applied.
In order to achieve the object of the present invention, the configuration and technical means of the present invention are as follows. That is, the compressed transmission method of the multimedia data according to the present invention,
In the compression transmission method for transmitting multimedia data using the compressor method,
Transmitting context information to a plurality of terminals; Receiving context damage information of the context information from at least one of the plurality of terminals; Comparing the number of terminals transmitting the contextual damage information with a threshold value; And transmitting a packet to the plurality of terminals according to the comparing step.
In addition, as another embodiment of the present invention, a method for receiving multimedia data according to the present invention,
In the method for receiving multimedia data using the compressor method,
Receiving context information from a network; Transmitting contextual damage information associated with the contextual information; And receiving a packet from the network comparing a threshold with a number of terminals transmitting the contextual damage information.

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Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

FIG. 6 is a block diagram showing a configuration of a system for compressing and transmitting MBMS data using the ROHC scheme according to an embodiment of the present invention. As shown in FIG. UTRAN 620 for compressing and transmitting using the mode, and a terminal 610 for forming a corresponding context from the received packet, and transmits the corresponding context damage information to the UTRAN 620 as a transmitting side when the context formation fails. Configure the MBMS data to be compressed.

The UTRAN 620 receives the total contextual damage information and the dynamic contextual damage information transmitted from the terminal 610 through the RRC layer 621, accumulates the respective numbers, and accumulates each of the RRC layer 621 or the header compression responsible layer ( In operation 622, it is determined to compare and determine whether the accumulated number of pieces of contextual damage information is greater than or equal to a predetermined threshold value.

As a result of comparing the number of each piece of contextual damage information with a threshold value, if the number of contextual damage information is greater than or equal to a predetermined threshold value, the header compression responsible layer 622 is quickly returned to a corresponding contextual state. Allow state transitions.

In this case, the threshold value may exist in the RRC layer 621 of the UTRAN or may exist in the header compression responsible layer 622 of the UTRAN.

Hereinafter, the operation and effect of the embodiment of the present invention configured as described above will be described.

In the embodiment of the present invention, U-mode of ROHC, which is a header compression technique used in UTRAN for MBMS service, does not only transmit a packet for context formation, but information on whether context formation has been successfully performed from a terminal on the receiving side. It is a technology that is considered to be able to increase the transmission efficiency by receiving and receiving, and maintaining so that the context formation is successful in the terminal more than a predetermined ratio.

As shown in FIG. 6, in the embodiment of the present invention, the header compression responsible layer 612 of the terminal 610 is a header compression responsible layer of the terminal when a packet received from the header compression responsible layer of the UTRAN damages the context. 612 transmits the contextual damage information to the RRC layer, and the RRC layer of the terminal transmits the contextual damage information using the RRC message to the RRC layer of the UTRAN on the transmitting side. The RRC layer 621 of the UTRAN 620 accumulates the context damage information received from the terminal according to the type of the context formation state.

Thereafter, the RRC layer 621 or the header compression layer 622 of the UTRAN 620 compares and determines whether the number of contextual damage information is greater than or equal to a predetermined threshold.

Therefore, when the number of contextual damage information is greater than or equal to a threshold value, the header compression layer 622 transitions back to a previous contextual or dynamic contextual form and transmits a packet for corresponding contextual form. Do it.

In brief, step by step, when the context forming is not successful in the receiving terminal 610, the transmitting side UTRAN 620 accumulates the number of contextual damage information transmitted from the receiving side, and And detecting whether the accumulated number of contextual damage information is greater than or equal to a predetermined threshold value, and rapidly transitioning to the corresponding context formation state to transmit a compressed header packet.

FIG. 7 is a flowchart illustrating a process of compressing and transmitting MBMS data by using an ROHC scheme according to an embodiment of the present invention. Referring to this, the process of each step will be described in detail as follows.

First, in the area providing one MBMS service, the entire context packet should be transmitted from the transmitting side UTRAN, that is, the entire context is not formed or damaged at the receiving side, that is, the operation process in the full context formation state of the UTRAN. Explain.

If the transmitting side is in the full context formation state (S701), the UTRAN initializes a variable (Failure ₁ ) for storing the number of terminals whose entire contexts to be transmitted from the terminal are damaged (S702), and then transmits the entire header packet to the terminal. (S703).

Then, the UTRAN starts transmitting the compressed header packet regardless of whether the entire context is normally formed in the entire header packet at the terminal (S704).

In the meantime, when the UTRAN receives full contextual damage information from the terminal (S708, S709), the UTRAN recognizes that the whole context is damaged due to the total header packet at the terminal, and then increases the number of terminals with the total context damaged by one. And store it in the variable (S710) and compare whether the cumulative number of terminals damaged by the entire context stored in the variable is greater than or equal to the threshold value (N1 _Threshold ) (S711), and if it is greater than or equal, return to the full context formation state again. The entire header packet transmission process is repeated (S701 to S703).

Of course, if the number of the terminal damaged the total context is less than the threshold, the total context stored in the variable maintains the cumulative number of the terminal is damaged, and continues the compressed header packet transmission process (S704).                     

As described above, in the present invention, when the entire context is damaged at the receiving terminal, the RRC layer of the terminal notifies the entire contextual damage information to the RRC layer of the UTRAN as the transmitting side as an RRC message. It has a threshold value for the number of, which may exist in the RRC layer of the UTRAN or the header compression responsible layer of the UTRAN.

Therefore, if there is a threshold value in the RRC layer of the UTRAN, the RRC layer of the UTRAN is compared with the threshold value of the number of the terminal is damaged from the entire context accumulated cumulative terminal, the cumulative number of the terminal is damaged If the threshold value is larger than the threshold value, the header compression state transitions to the full context formation state and the entire header packet is transmitted again. If the threshold value exists in the header compression layer of the UTRAN, the RRC layer of the UTRAN is transmitted from several terminals. The cumulative total context is transmitted to the header compression responsible layer to transmit the number of damaged terminals, the header compression layer to compare the threshold value, and if the cumulative number of the terminal in which the total context is damaged greater than the threshold, the header compression state Causes the transition to full contextual form and sends the entire header packet again.

As described above, when the number of the terminal in which the whole context is damaged is greater than or equal to the threshold value, and the transition to the full context forming state is performed again, the cumulative number of the terminals in which the whole context is damaged is initialized to zero.

Next, in the area for providing one MBMS service, the dynamic context is not formed or damaged at the receiving end, so that the dynamic context forming packet should be transmitted from the UTRAN as the transmitting side, that is, during operation in the dynamic context forming state of the UTRAN. Explain.                     

When the sender is in the dynamic context forming state (S705), the UTRAN initializes a variable (Failure ₂ ) for storing the number of terminals whose dynamic context is damaged to 0 once (S706), and transmits the dynamic context forming packet to the terminal. (S707).

Then, the UTRAN starts transmitting the compressed header packet regardless of whether the dynamic context is normally formed from the terminal to the dynamic context forming packet (S704).

In the meantime, when the UTRAN receives dynamic contextual damage information from the terminal (S708, S709), the UTRAN recognizes that the dynamic context is damaged due to the dynamic context formation packet at the terminal, and then the number of the terminal with the damaged context is one. Increase and store in the variable (Failure ₂ ) (S712), compare the cumulative number of the terminal damaged the dynamic context stored in the variable is greater than or equal to the threshold value (N2 _Threshold ) (S713), if the dynamic value is greater or equal again dynamic Returning to the context forming state, the process of transmitting the dynamic context forming packet is repeatedly performed (S705 to S707).

Of course, if the cumulative number of the terminal damaged the dynamic context is less than the threshold, the dynamic context stored in the variable maintains the number of the terminal damaged, and continues the compressed header packet transmission process (S704).

As described above, in the present invention, if the dynamic context is damaged in the terminal, the RRC layer of the terminal informs the dynamic context damage information to the RRC layer of the UTRAN as an RRC message, wherein the UTRAN has a threshold for the dynamic context damage information. The threshold may be present in the RRC layer of the UTRAN or in the header compression responsible layer of the UTRAN.                     

Therefore, when a threshold exists in the RRC layer of the UTRAN, the RRC layer of the UTRAN compares the number of terminals with damaged dynamic contexts accumulated from several terminals with a threshold value, so that the cumulative number of terminals with corrupted dynamic contexts is increased. If it is larger than the threshold value, the header compression state transitions to the dynamic context formation state and transmits the dynamic context formation packet again. If the threshold value exists in the header compression layer of the UTRAN, the RRC layer of the UTRAN is transmitted from multiple terminals. The cumulative dynamic context is transmitted to the header compression responsible layer, and the header compression responsible layer is compared to a threshold value. When the cumulative number of the dynamic context damaged terminals is greater than a threshold, header compression is performed. The state transitions to the dynamic context forming state, which in turn sends the dynamic context forming packet.

As described above, when the cumulative number of terminals damaged by the dynamic context is greater than or equal to a threshold value, the cumulative number of terminals damaged by the dynamic context is initialized to zero.

Particularly, in the operation method of the global context forming state, when the cumulative number of the terminal in which the entire context is damaged is greater than or equal to the threshold value and the transition is made to the entire context forming state, the dynamic context is damaged as well as the cumulative number of terminals in which the celestial context is damaged The cumulative number of terminals is also initialized to zero.

As described in detail above, the present invention provides a system and method for compressing and transmitting multimedia data. When a plurality of terminals fail to form a full context, the UTRAN, which is a transmitting party, quickly transitions to a full context and fails to form a dynamic context. In this case, by allowing the UTRAN to quickly transition to the dynamic context forming state, a plurality of terminals can normally receive the MBMS data compressed in the U-mode of the ROHC scheme, thereby increasing the transmission efficiency.

Claims (35)

In the compression transmission method for transmitting multimedia data using the compressor method, Transmitting context information to a plurality of terminals; Receiving context damage information of the context information from at least one of the plurality of terminals; Comparing the number of terminals transmitting the contextual damage information with a threshold value; And And transmitting the packet to the plurality of terminals according to the comparing step. The method of claim 1, wherein the context information is global context information or dynamic context information. 3. The method of claim 2, wherein the contextual damage information is global contextual damage information or dynamic contextual damage information. delete The method of claim 1, wherein the contextual damage information is received through a Radio Resource Control (RRC) message. The method of claim 1, wherein the compression method is a U-mode of a robust header compression (ROHC) method. The method of claim 1, wherein the comparing is performed in a Radio Resource Control (RRC) layer or a header compression management layer. 8. The method of claim 7, wherein if the number of terminals transmitting the contextual damage information is greater than or equal to the threshold value, the header compression state is changed to a full context forming state for retransmitting the entire header packet or the dynamic header packet is retransmitted. Compression transmission method of the multimedia data, characterized in that the transition to the context-forming state. delete 10. The method of claim 8, wherein when the threshold is present in the header compression responsible layer, the header compression responsible layer transitions the header compression state to a full context forming state or a dynamic context forming state. Transmission method. 10. The method of claim 8, wherein if the number of terminals transmitting the contextual damage information is smaller than the threshold, compression header packet transmission is continued. In the method for receiving multimedia data using the compressor method, Receiving context information from a network; Transmitting contextual damage information associated with the contextual information; And And receiving a packet from the network comparing the threshold number and the number of terminals transmitting the contextual damage information. The method of claim 12, wherein the context information is global context information or dynamic context information. The method of claim 13, wherein the contextual damage information is global contextual or dynamic contextual damage. The method of claim 12, wherein the contextual damage information is transmitted through a Radio Resource Control (RRC) message. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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