KR100765122B1 - Apparatus for controlling transmission of full header packet and compression header packet in communication system supporting packet header compression and method thereof - Google Patents

Abstract

The present invention relates to a data transmission apparatus and method for compressing and transmitting header information of packet data in a wired / wireless communication system and feeding back a result to control packet transmission.

The present invention provides a header compression device for compressing a header of data received from a higher layer and converting the header of a data packet transmitted from a higher layer into a total header packet and / or a compressed header packet for one packet stream, and a header compression control for controlling the packet stream. A device and a data transmission device for delivering the compressed whole header packet and / or the compressed header packet to a lower layer; The link control layer determines a buffer and a transmission device for storing or transmitting the data received from the header compression responsible layer according to the control of the transmission control device, and discriminates the data that failed to be transmitted among the data transmitted to the receiving side, thereby differing from the transmission failure information. A transmission failure determining apparatus for transmitting to a layer, the communication system comprising: compressing a header of data received from an upper layer in a header compression responsible layer to deliver the entire header packet or / and a compressed header packet to a link control layer; The link control layer stores the received data in a storage means or transmits the data to a receiver and then determines whether there is data that failed to be transmitted among the data transmitted to the receiver. Header compression charge by passing to compression charge layer The layer is characterized by controlling the transmission of the entire header packet and the compressed header packet.

Description

Apparatus for controlling transmission of full header packet and compression header packet in communication system supporting packet header compression and method

1 is a diagram showing a network structure in a PS domain among network structures recommended by 3GPP.

2 illustrates a user plane for transmitting user data.

3 is a view showing a control plane (Control plane) for the transmission of the control signal

4 is a diagram illustrating a structure of a radio access interface protocol between a UE and UTRAN based on 3GPP radio access network standards

5 is a diagram showing the structure of a general header of TCP / IPv6

6 is a diagram showing the structure of an entire header when using the header compression method of TCP / IPv6;

7 is a view showing the structure of the entire header when using the header compression method of UDP / IPv6

8 is a diagram illustrating the structure of a Context State packet that is conventionally used to recover a context.

9 is a block diagram of a system for transmitting a packet using a header compression technique.

10 is a block diagram of a system using the Quick Context Recovery method proposed in the present invention.

The present invention relates to a data transmission apparatus and method for compressing and transmitting packet information of packet data of a wired / wireless communication system and feeding the result back to control packet transmission. In particular, the header compression of a 3GPP asynchronous (UMTS) mobile communication system The PDCP layer, the responsible layer, receives the entire header packet or the compressed header packet transmission result from the RLC layer, the lower link control layer, and adjusts the transmission of the entire header packet and the compressed header packet to improve the transmission efficiency and the efficiency of compression restoration. An apparatus and method for data transmission in a UMTS system are described.

More specifically, in the present invention, the header compression responsible layer performs header compression on the packet received from the upper layer and delivers the header to the lower link control layer, and the link control layer transmits it to the receiving side. A header compressor for compressing the header of the data received from the header and converting the header into a full header packet or / and a compressed header packet, a header compression control device for controlling the header, and the compressed full header packet or / and a compressed header packet A header compression responsible layer formed of a data transmission device for transmitting the data; A buffer and a transmission device for storing the received data or transmitting the received data to a receiving side under the control of a transmission control device, and a transmission failure judging device for transmitting the transmission failure information to a higher layer by determining data that failed to be transmitted among the data transmitted to the receiving side. Link control layer consisting of; communication system consisting of.

In the system, the header of the data received from the upper layer is compressed in the header compression responsible layer to deliver the entire compressed header packet and / or the compressed header packet to the link control layer, and the link control layer stores the received data. Determining whether there is data that failed to be transmitted among the data that is stored in or transmitted to the receiver and then transmitted to the receiver, and when there is data that failed to be transmitted, transmission failure information of the data is transmitted to the header compression responsible layer, and the header compression responsible layer The present invention relates to a data transmission apparatus and a method for controlling transmission of an entire header packet and a compressed header packet.

Hereinafter, the prior art will be described.

First, a general background of the prior art and the present invention will be described.

ETSI of Japan and Japan to prepare detailed specifications of the 3rd generation WCDMA technology (asynchronous IMT-2000) based on the 2nd generation global network for mobile communications (GSM) and the general packet radio service (GPRS). ARIB / TTC, Tl in the US, CWTS in China, and TTA in Korea have formed a project called the Third Generation Partnership Project (hereinafter abbreviated as 3GPP). A third generation mobile communication system that can provide multimedia services such as data in a wireless environment is under development.

The 3GPP supports five activities in its technical specification groups (abbreviated as TSG) for fast and efficient project management and technology development, and each TSG has standards associated with the areas it is assigned to. Responsible for the development, approval, and management of the

Among them, the Radio Access Network (hereinafter, abbreviated as RAN) group aims to define a new wireless access network in the third generation mobile communication system, and includes a terminal and a UMTS wireless terrestrial radio access network (hereinafter, Developing specifications for the functions, requirements, and interfaces of the UTRAN (abbreviated as UTRAN), and the group of core networks (abbreviated as CN under the Core Network) group is responsible for the functions and requirements of the CN for linking UTRAN to the circuit backbone network or packet backbone network. We are developing specifications for matters and interfaces.

FIG. 1 shows a network structure in a packet domain (hereinafter, abbreviated as PS domain) among network structures recommended by TSG-RAN and TSG-CN.

Referring to FIG. 1, first, UTRAN is composed of several radio network subsystems (hereinafter referred to as RNS), and one RNS includes several Node Bs (base stations) and one radio network controller (Radio). Network Controller: hereinafter abbreviated as RNC).

The CN has a different structure depending on whether it is a circuit network or a packet network. In the case of the packet network considered in the present invention, several GPRS support nodes (hereinafter referred to as SGSNs) and one gateway GPRS support node ( Gateway GPRS Support Node (hereinafter abbreviated as GGSN).

The role of each part of FIG. 1 is as follows.

The Node B serves as an access point for the UE (hereinafter referred to as UE) to access the UTRAN, and the RNC allocates and manages radio resources for each UE.

There are two types of RNCs: Control RNC (hereinafter referred to as Control RNC) which is in charge of management of common radio resources and RNC (Serving RNC: hereinafter called SRNC) to manage dedicated radio resources assigned to each terminal. Dividing).

In addition, from the standpoint of a specific UE, the RNS in which its SRNC is located is specifically referred to as a responsible RNS (serving RNS).

SGSN is responsible for routing information transmitted from UTRAN, GGSN serves as a gateway to pass information when the destination of the information is a network other than the current CN.

PDN (Packet Domain Network) is the backbone network of the PS domain, and supports connection in the PS domain with other networks.

In addition, the interface of each part of FIG. 1 uses the following unique names to distinguish each other.

Uu between UE and Node B, Iub between Node B and RNC, Iur between RNC and RNC, Iu between RNC and SGSN, Gn interface between SGSN and GGSN or between SGSN and SGSN.

FIG. 1 illustrates an example of a network structure. In reality, Iur may or may not exist, and Iur may exist between RNCs belonging to different SGSNs.

In addition, Gn between SGSNs may or may not be present.

Looking at the network structure of Figure 1 in more detail can be represented by a hierarchical structure as shown in FIG.

FIG. 2 shows a user plane (hereinafter referred to as U-plane) for transmitting user data, and FIG. 3 shows a control plane (hereinafter referred to as C-plane) for transmitting control signals.

Among these layers, a detailed layer of the Uu interface, which is a wireless section in particular, is shown in FIG. 4, and in detail, the U-plane includes a packet data convergence protocol layer (hereinafter abbreviated as PDCP) layer and radio link control. A Layer (Radio Link Control Layer: hereinafter referred to as RLC), a Medium Access Control Layer (hereinafter referred to as MAC) and a first layer include a Physical Layer (hereinafter referred to as Ll). The control plane includes a radio resource control layer (hereinafter referred to as RRC), an RLC layer, a MAC layer, and an Ll layer.

Hereinafter, each layer of FIG. 4 will be described.

The Ll layer provides an information transfer service to an upper layer using various wireless transmission technologies.

The upper MAC layer is connected through a transport channel, and data between the MAC layer and the physical layer moves through the transport channel.

The transport channel is divided into a dedicated transport channel and a common transport channel, respectively, depending on whether the terminal can be used exclusively or shared by multiple terminals.

The MAC layer provides a reassignment service of MAC parameters for allocating and reallocating radio resources.

The upper layer is connected to the RLC layer by a logical channel, and various logical channels are provided according to the type of information to be transmitted.

In general, a control channel is used to transmit control plane information, and a traffic channel is used to transmit information of a user plane.

The RLC layer provides a radio link establishment and release service. In addition, the RLC performs a segmentation and reassembly function of an RLC Service Data Unit (hereinafter, abbreviated as SDU) from an upper layer of the user plane.

The RLC SDU is sized to fit 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).

The RLC layer operates in three ways: transparent mode, unacknowledged mode, and acknowledgment mode, depending on how the RLC SDU comes down from the upper layer. Or there is an RLC buffer for storing RLC PDUs.

The PDCP layer is located above the RLC layer so that data transmitted through a network protocol such as IPv4 or IPv6 can transmit data in a form suitable for the RLC layer.

In addition, it reduces unnecessary control information used in the wired network so that it can be efficiently transmitted through the wireless interface.

This function is called header compression and can be used to reduce the amount of header information for TCP / IP as an example.

The RRC layer provides an information broadcast service for broadcasting information to all terminals located in an arbitrary area. It is also responsible for control plane signal processing for control signal exchange in the third layer, and has a function of setting, maintaining, and releasing radio resources between the terminal and the UTRAN.

In particular, the RRC has a function of setting, maintaining, and releasing a radio bearer (hereinafter, abbreviated as RB), and allocating, relocating, or releasing radio resources required for radio resource access. In this case, the RB means a service provided by the second layer for data transmission between the terminal and the UTRAN.

That is, the configuration of one RB means a process of defining a protocol layer and a channel characteristic necessary for providing a specific service in a wireless section, and setting each specific parameter and operation method.

Hereinafter, the IP header compression algorithm used in the PDCP will be described in detail with reference to FIGS. 5, 6 and 7. FIG.

Let's look at the header compression technique performed by the PDCP layer located in the terminal and the UTRAN in detail. The reason why header compression is necessary when transmitting an IP packet, especially when transmitting an IP packet through a wireless interface, is because the header size of the IP packet is not so small as to be negligible compared to the packet's payload size. to be.

For example, consider a case where a wireless terminal receives data from an IP network.

Each packet is accompanied with IP header information so that it can be routed in the IP network. In the case of IPv4, 24 octets are used only in the IP header, and in the case of IPv6, 40 octets are required. If the TCP layer or the UDP layer is located above the IP layer, an additional 24 octets and 8 octets are required. Therefore, when transmitting a packet using TCP / IPv6, at least 64 octets are required, and when transmitting using UDP / IPv6, at least 48 octets of header information are required per packet.

However, consider the case of Voice Over IP (VoIP) service transmitting using UDP / IPv6. The header size of 48 octets is the size of the voice payload compressed by the voice codec. In the case of 20 octets, the size is very large.

Therefore, if the transmission is in the form of an IP packet, it can be easily predicted that when used in a link having a limited transmission bandwidth such as a wireless link, a large performance degradation will occur. Due to such a need, a header compression technique capable of reducing packet header information for a long time has been studied.

The header compression technique utilizes the property that header information of packets belonging to the same packet stream is almost the same.

In other words, packet streams are packets having very similar header information, and generally, packets used to provide a specific service may be referred to as identical packet streams.

For example, when a packet is transmitted through TCP / IP, it can be considered that packets transmitted with the same address and the same port number belong to the same packet stream.

To understand the principle and compression ratio of the header compression technique, look at the TCP / IPv6 header field as shown in FIG. First, in the definition of a packet stream, the address fields of IPv6 and the port number of the TCP header belong to the same packet stream and will always be constant.

In addition, the version field indicates that IPv6 is used, and the Next Header field indicates that the header information following the IPv6 header is TCP. Therefore, the version field may be the same for the corresponding packet stream.

The traffic class field indicates the priority of the packet, and the flow label field is used when control of the packet by priority is required.

At this time, if the Flow Label value is set to a value other than 0, the traffic class field in front of the Flow Label field does not change.

However, if the Flow Label value is set to 0, the value of the traffic class field may change. However, since packets having values of different traffic class fields belong to different packet streams, the values of the traffic class field and the flow label field do not change for one packet stream.

The Hop Limit field is decremented by 1 each time the router passes through the ground. If this value is less than 0, the packet is discarded. In general, since packets are transmitted through the same path in the network, this value is also almost constant for a particular packet stream.

In addition, the Offset field indicates the starting point of the TCP data, so the value is constant.

Therefore, when packets belonging to the same packet stream are transmitted, fields in which the information does not change according to transmission of the packet occupy almost all of the header fields of FIG. Corresponding.

A detailed description of the header compression technique can be found in the official technical papers on Internet technology published by the Internet Engineering Task Force (IETF). For reference, the PDCP layer uses a header compression technique based on RFC2507 and RFC3095.

The header compression method in the RFC2507 may use a different compressor method depending on whether the protocol located above the IP layer is TCP or other protocol.

In other words, protocols that do not use TCP, such as UDP / IP, use a method called "Compressed Non-TCP", and when using TCP, "Compressed TCP" and "Compressed" depending on the method of transmitting variable header fields. TCP nodelta ".

The compressed TCP technique is a method of transmitting the difference between packets without sending the entire field value by using the fact that the difference of the variable header field values is not so large between consecutive packets, and the "Compressed TCP nodelta" is variable. How to send header fields as they are.

In order to restore the compressed header at the receiver side, a reference value is required. Therefore, in all header compression techniques, a task of transmitting a full header including all fields of an uncompressed header should always be preceded. In the entire header, a portion that does not change in a specific packet stream, such as the colored portion of FIG. 5, is used for restoring a compressed header to be transmitted later. As shown in the colored portion of FIG. 5, information necessary for recovering compressed header information transmitted later is defined as a context of a corresponding packet stream. Therefore, this context becomes reference information which can restore the compressed header to the header before compression. In addition, define a packet including all headers necessary for updating or generating a context as a whole header packet, and define a packet to be transmitted with header information compressed as a compressed header packet.

If a change of context occurs during the transmission of a packet, the changed total header must be transmitted first before transmitting the compressed header information. At this time, since the total header packet is much larger than the general compressed header packet, the transmission of the total header packet should be reduced as much as possible to increase the transmission efficiency. In addition, it is necessary to construct a packet stream appropriately so that such a field change does not occur frequently in one packet stream.

Let's take a look at the header compression technique used when compressing the header using "Compressed TCP" or "Compressed TCP nodelta" like TCP / IP.

As mentioned above, in order to use the header compression technique for a specific packet stream, a process of first transmitting the entire header is required.

However, since there may be more than one packet stream in the network, an identifier indicating a context for each packet stream is defined as a compression identifier (hereinafter, abbreviated as CID).

The CID value always has a length of 8 bits for a TCP packet, and when transmitting a compression header or the entire header, the CID value should always be transmitted together.

The transmitted total header information is stored at the receiving side according to the CID value. When the packet arrives, the entire header information is read based on the CID value and the original header information is restored.

6 is a structure of an entire header transmitted when a header compression technique is used for a TCP / IPv6 packet. The total header of FIG. 6 is the same for both cases of "Compressed TCP" and "Compressed TCP nodelta".

Since the original TCP / IPv6 header field does not have a CID field and therefore cannot contain a CID value, it is necessary to find an appropriate field to insert it. At this time, since the existing "payload length" field is information that can be received from a lower layer, there is no need to use the field. Therefore, the CID can be transmitted without including the length information in these fields.

When the header compression scheme is used for the TCP / IPv6 packet in the compressed TCP case, the compression header transmitted is composed of uncolored parts of the TCP / IPv6 header of FIG. 6, and its size is generally 4 to 7 octets. . At this time, the CID field of the field of the compression header has a fixed value, the Checksum field has a variable value, the other fields except this transmits the difference (difference) with the previous compression header.

When the header compression scheme is used for the TCP / IPv6 packet in the case of Compressed TCP nodelta, the compression header transmitted is the remaining fields except the CID field of the IPv6 header and the source port and destination port fields of the TCP header. It is composed of 17 octets in size. At this time, the CID field among the fields of the compressed header has a fixed value, and the remaining fields except this have a variable value.

Protocols that do not use TCP, such as UDP / IP, compress the header using a method called "Compressed Non-TCP". This method is similar to TCP / IP, so let's take a quick look.

As in the case of TCP / IP, in order to use the header compression technique for a specific packet stream, the entire header is first transmitted, and a CID for distinguishing each packet stream is required. The CID value has a length of 8 bits or 16 bits. When transmitting a compressed header or the entire header, the CID value should always be transmitted together.

The UDP / IP header compression technique additionally uses the "Generation" field indicating the generation of the header information as well as the CID to distinguish each packet stream. The Generation field indicates how old the header information of the packet is. It is always transmitted with the CID value when the packet is transmitted.

7 is a structure of an entire header transmitted when a header compression technique is used for a UDP / IPv6 packet.

Since there is no CID field or Generation field in the original UDP / IPv6 header field, the value cannot be entered. Therefore, CID and Generation are transmitted in the existing "payload length" field or "length" field. In the figure, CID uses only CID (1) when using 8-bit CID, only CID (2) when using 16 bits, and Generation uses part of the payload length field.

When the header compression scheme is used for the UDP / IPv6 packet, the compression header transmitted is composed of parts of the UDP / IPv6 header of FIG. 7 not colored in the figure, and the size thereof is generally 4 to 5 octets. At this time, the CID field and the Generation field among the fields of the compression header have a fixed value, and the Checksum field has a variable value.

As described above, the use of the header compression technique has the advantage of significantly reducing the header size of the jacket. In particular, when trying to transmit a packet through an air interface, the header compression is necessary because the packet header size is considerably larger than the jacket payload size.

9 is a block diagram of a system for transmitting a packet using a header compression technique.

The PDCP layer of the conventional system causes the header compression device to compress the header of data received from the upper layer in the header compression control device. The data converted into the whole header packet or the compressed header packet is transferred to the RLC layer through the data transmission device.

In the RLC layer, the transmitted data is stored in a buffer or transmitted to a receiver through a transmission device according to the control information of the transmission control device.

In the case of using the Compressed TCP scheme as the header compression scheme, for one packet stream, the sender first transmits the entire header packet to form a context at the receiver side, and for subsequent packets, Send using a compression header that represents only the difference.

If the entire header packet is not successfully transmitted, since the context is not configured correctly at the receiver side, the receiver side fails to restore the compressed header afterwards. In addition, even if the compressed header packet is not successfully transmitted, since the context of the receiver is not updated correctly, subsequent compression headers cannot be restored as in the case where the entire header packet is lost.

The damaged context can be recovered only by a new full header of the context, and the receiver sends a CONTEXT_STATE packet requesting the sender to send a new full header for the context. do.

8 is a diagram illustrating the structure of a Context State packet that is conventionally used for the recovery of a Context.

The CONTEXT_STATE packet consists of several CID fields, where each CID field represents one corrupted context, that is, one corrupted packet stream. This CONTEXT_STATE packet is not used whenever one context is damaged, but is collected and sent to the sender when more than one context is damaged. In addition, since the transmission of such CONTEXT_STATE packets from the receiving side to the transmitting side itself wastes radio resources, RFC2507 limits its frequency of use.

Therefore, if a lost packet occurs in using the Compressed TCP header compression scheme, the receiving side should spend some time before recovering the relevant context. Since they do not know that they are damaged, they unnecessarily transmit compressed header packets, which wastes a lot of radio resources.

Accordingly, the present invention is to solve the above-described problems, when the packet is transmitted using the Compressed TCP header compression technique in the UMTS system, the PDCP layer of the transmitting side performing the header compression function in one packet stream If even one of the transmitted header packets or one of the compressed header packets is received from the lower layer RLC layer that the transmission has failed, it recognizes that the context of the packet stream is damaged, and immediately returns to the context. By transmitting a new full header packet for the receiver, it is possible to quickly recover a damaged context at the receiving side, and to provide an apparatus and a method for increasing the transmission efficiency and the restoration efficiency by the header compression technique.

Communication system for transmitting and controlling the packet data of the present invention,                     

The transmitting header compression responsible layer compresses a header of data transmitted from an upper layer and converts the header into a total header packet and / or a compressed header packet, a header compression control device for controlling the header header, and the compressed total header packet. Or / and a data transmission device for delivering a compressed header packet to a lower layer; The link control layer determines a buffer and a transmission device for storing or transmitting the data received from the header compression responsible layer according to the control of the transmission control device, and discriminates the data that failed to be transmitted among the data transmitted to the receiving side, thereby differing from the transmission failure information. Characterized in that it consists of; transmission failure determination device for transmitting to the layer.

In addition, the packet data transmission method of the present invention restores the compressed header information in the compressed header packet by using the total header information in the entire header packet in the header compression layer on the receiving side for one packet stream. In the header compression responsible layer of the transmitting side of the communication system for transmitting the entire header packet having all the header information or the compressed header packet having the compressed header information, transmitting the packet through a link control layer which is a lower layer. Wow; Receiving a transmission result of the packet from the link control layer; And when the transmission failure information is received for the one or more packets, transmitting the subsequent first packet with respect to the packet stream to all header packets.

In addition, the present invention is to recover the compressed header information in the compressed header packet by using the total header information in the entire header packet in the PDCP layer, which is the header compression responsible layer on the receiving side for one packet stream (Packet Stream) A transmitting side PDCP layer of a UMTS system capable of mixing a total header packet having header information or a compressed header packet having compressed header information, the method comprising: transmitting the packet through an RLC layer which is a link control layer; Receiving the transmission result of the packet from the RLC layer; And when the transmission failure information is received for the one or more packets, transmitting the subsequent first packet with respect to the packet stream to all header packets.

Preferably, the transmission failure information of the present invention includes identification information and / or transmission failure indication information of the corresponding packet.

Preferably, in the present invention, when using a compression method in which the context is updated by an arbitrary header packet or a compressed header packet, any one of the packets delivered by the header compression responsible layer to the link control layer after header compression is If the transmission to the receiver fails, the link control layer informs the header compression responsible layer of identification information and / or transmission failure indication information of the corresponding packet.

Preferably, in the present invention, the compression method in which the context is updated by any packet is a compressed TCP method.

Preferably, in the present invention, when the header compression responsible layer receives the transmission failure information of an arbitrary packet from the link control layer, the first packet of the subsequent packet stream is transmitted to the entire header packet.

Preferably, in the present invention, the header compression responsible layer transmits a new whole header packet of a relevant context to the receiver as soon as the transmission failure information of an arbitrary packet is received from the link control layer.

Preferably, in the present invention, the PDCP layer, which has received transmission failure information from the RLC layer, compresses the first packet after using the same CID as the CID of the packet which failed to be transmitted, and delivers the first packet to the RLC layer by compressing the entire header packet.

Preferably, in the present invention, when using a compression method in which the context is updated only by the entire header packet, the header header responsible layer may have failed to transmit the entire header packet to the receiver side among the packets delivered to the link control layer after header compression. In this case, the link control layer informs the header compression responsible layer of identification information and / or transmission failure indication information of the corresponding packet.

Preferably, in the present invention, when the header compression responsible layer receives the transmission failure information of the entire header packet from the link control layer, the header compression responsible layer transmits the first packet after the corresponding packet stream to the entire header packet.

Preferably, the upper layer of the PDCP layer that is responsible for header compression in the present invention is an RRC layer that manages radio resources, and when the radio bearer is set up, the RRC layer is an RLC layer and the upper layer stores information of SDUs discarded from the RLC. It is characterized by setting to inform.

Preferably, in the present invention, when the RRC sets up the RLC, the RRC determines whether to transmit the SDU discard information through a transmission failure report indicator and informs the upper layer of the information.

Preferably, in the present invention, when the PDCP layer delivers the PDCP PDU to the RLC layer, the PDCP layer is instructed to inform the PDCP layer of the transmission failure result for the corresponding PDU.

Preferably, when the PDCP layer delivers the PDCP PDU to the RLC layer, the PDCP layer delivers a transmission failure report indicator together with the corresponding PDU so that the RLC layer informs the upper layer when the SDU is discarded.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, an apparatus and a method for controlling transmission of a total header packet and a compressed header packet in a communication system supporting header compression of a packet according to the present invention will be described with reference to the accompanying drawings.

First, in the UMTS system of the present invention, the RLC layer, which has received a packet from the transmitting PDCP layer, transmits the transmission failure result for the packet transmitted to the receiving side to the PDCP layer, whereby the PDCP layer efficiently transmits the entire header packet and the compressed header packet. To control it. To this end, it is necessary to add a function for notifying the PDCP layer of the result of transmission failure of the PDCP PDU from the upper layer regardless of the mode.

9 is a block diagram of a system for transmitting a packet using a header compression technique.

As described above, a description will be given of a system for transmitting a packet using a header compression technique, and FIG. 10 is a description of a system using the Quick Context Recovery method proposed by the present invention.                     

10 will be described.

The system of FIG. 10 includes a header compression apparatus for compressing a header of data received from an upper layer and converting the header into data for a total header packet and / or a compressed header packet, a header compression control apparatus for controlling the header, and the compressed total header packet or / And a header compression responsible layer consisting of a data transmission device for delivering a compressed header packet to a lower layer; The buffer and the transmission device for storing or transmitting the data transmitted from the header compression responsible layer to the receiving side according to the control of the transmission control device, and determine the data that failed to transmit among the data transmitted to the receiving side to transmit the transmission failure information to the upper layer And a link control layer comprising a transmission failure determining device.

In the UMTS system, the header compression layer is a PDCP layer and the link control layer is an RLC layer.

Data converted from the header compression device of the PDCP layer to the entire header packet or the compressed header packet are transferred to the RLC layer through the data transmission device.

The RLC layer stores the received data in a buffer or transmits the received data to the receiver through the transmission device according to the control information of the transmission control device.

In this case, the data transmitted to the receiving side in the RLC layer is determined by the transmission failure determining apparatus in the transmission failure determination device. If the transmission of the data is determined to be failed, the transmission failure determining apparatus determines the transmission failure information. It is delivered to the header compression control device of PDCP layer.

The PDCP layer, which has received transmission failure information from the RLC layer, compresses the first packet after using the same CID as the CID of the packet that failed to be transmitted to the entire header packet and delivers it to the RLC layer.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

In other words, in case of using the compression method in which the context is updated only by the entire header packet, the link compression layer fails to transmit the header header to the receiver side among the packets delivered by the header compression layer to the link control layer after header compression. The control layer informs the header compression responsible layer of identification information and transmission failure indication information of the corresponding packet.

 Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

The present invention provides a system for transmitting packet data by using a header compression technique. In the case where damage occurs in the context of a receiver due to a failure in transmission of an arbitrary packet, the header control layer of a transmitting side is a lower link control layer. As soon as the transmission failure information is received from the packet, the new whole header packet of the context is transmitted to the receiving side, thereby preventing the packet from being lost and recovering the context more quickly, thereby improving transmission efficiency and compression. Restoration efficiency can be improved.

Claims (44)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A method of transmitting a packet to a receiver by a transmitter having a radio protocol having an upper layer and a lower layer, If the upper layer receives the information of the transmission failure for at least one packet from the lower layer, the upper layer includes determining whether to send the next packet as a full header packet. Way. The method of claim 17, wherein the higher layer is And transmitting the next packet as a full header packet. 18. The method of claim 17, wherein the information of the transmission failure is And a lower layer indicating that the packet has been discarded. 20. The method of claim 19, wherein the information of the transmission failure is And an indicator (MUI) used to indicate a packet discarded by a lower entity (RLC). The method of claim 17, wherein the lower layer is A method for managing total header transmission, characterized by operating in a transparent mode (TM), an unresponsive mode (UM), or a response mode (AM). 18. The method of claim 17, wherein each time the lower layer reports that it has discarded at least one packet, the higher layer decides to send the next packet as a full header packet. 18. The method of claim 17, wherein sending the next packet as a full header packet is performed regardless of the request of the receiver. The method of claim 17, wherein the higher layer is And transmitting information indicating whether the upper layer should be notified of the discarded packet to the lower layer, and receiving information on the discarded packet from the lower layer. 18. The method of claim 17, wherein the information from the lower layer is And a transmission result for each packet. 18. The method of claim 17 wherein a context identifier (CID) is transmitted with the full header packet so that each packet stream is identifiable. The method of claim 17, wherein the higher layer is Part of a Packet Data Convergence Protocol (PDCP) entity, wherein said lower layer is part of a Radio Link Control (RLC) entity. 18. The apparatus of claim 17, wherein the transmitter is Network, the receiver is a terminal, the transmitter is a terminal, and the receiver is a network. 18. The method of claim 17, wherein the packets are And a part of a Transmission Control Protocol (TCP) stream. A transmitter having a radio protocol used for managing full header transmission when transmitting a data packet to a receiver, And a higher layer that determines whether to send the next packet as a full header packet when the upper layer receives information on transmission failure of at least one packet from the lower layer. The method of claim 30, wherein the upper layer is A header compressor for receiving a packet stream and outputting a full header packet and a compressed header packet; A data transmitter for delivering the entire header packet and the compressed header packet to be transmitted by the header compressor to a lower layer; And a header compression controller that receives information from a lower layer to control the header compressor to output all header packets or compressed header packets to be delivered to the data transmitter. The method of claim 30, wherein the lower layer, A buffer and transmitter configured to receive and store the entire header packet and the compressed header packet transferred from the upper layer; A transmission failure identifier for providing information on transmission failure of at least one packet in the packet stream to a higher layer; And a transmission controller controlling the buffer and the transmission unit to transmit the entire header packet and the compressed header packet to a receiver. The method of claim 30, wherein the upper layer is Send the next packet as a full header packet. The method of claim 30, wherein the information about the transmission failure Transmitter indicating that the lower layer has discarded the packet. The method of claim 34, wherein the information about the transmission failure And an indicator (MUI) used to indicate a packet discarded by a lower entity (RLC). The method of claim 30, wherein the lower layer is And operating in a transparent mode (TM), a non-responsive mode (UM), or a response mode (AM). The method of claim 30, wherein the upper layer is And whenever a lower layer reports that it has discarded at least one packet, it determines to send the next packet as a full header packet. 31. The transmitter of claim 30, wherein sending the next packet as a full header packet is performed irrespective of the request of the receiver. The method of claim 30, wherein the upper layer is And transmitting a parameter indicating whether a higher layer should be informed about a packet discarded to the lower layer, and receiving information from the lower layer. 31. The method of claim 30, wherein the information from the lower layer is Transmitter related to the transmission result for each packet. 33. The transmitter of claim 30 wherein a context identifier (CID) is transmitted with the entire header packet so that each packet stream is identifiable. The method of claim 30, wherein the upper layer is A part of a Packet Data Convergence Protocol (PDCP) entity, wherein said lower layer is part of a Radio Link Control (RLC) entity. 31. The apparatus of claim 30, wherein the transmitter is A network and the receiver is a terminal or the transmitter is a terminal and the receiver is a network. The method of claim 30, wherein the packet is  And part of a Transmission Control Protocol (TCP) stream.

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