WO2010064783A1

WO2010064783A1 - Communication method and device in communication system and recording medium having recorded program for carrying out communication method

Info

Publication number: WO2010064783A1
Application number: PCT/KR2009/005288
Authority: WO
Inventors: Myung San Bae; Mi Kyoung Kim; Young Soo Jung
Original assignee: MTH Inc
Current assignee: MTH Inc
Priority date: 2008-12-02
Filing date: 2009-09-17
Publication date: 2010-06-10
Anticipated expiration: 2011-06-02
Also published as: KR100906098B1

Abstract

Communication method and device in a communication system and a recording medium having recorded thereon a program for carrying out the communication method are disclosed. The method of converting data includes the steps of: receiving a higher-layer header separated from one or more layer 3 PDUs (Protocol Data Units); compressing the higher-layer header; receiving location information on a location in a transmitted data storage unit in which layer 3 data of the one or more layer 3 PDUs from which the higher- layer header is separated is stored; performing an encrypting operation using the location information on the location at which the one or more layer 3 data is stored and the compressed one or more higher-layer headers corresponding to the location information; and generating and outputting a transmission block by adding a layer 2 header to a transmission unit packet generated by the encrypting operation. Here, the layer 2 is a data link layer. As a result, it is possible to optimally use a memory when a layer 2 processes data sent from a higher layer.

Description

COMMUNICATION METHOD AND DEVICE IN COMMUNICATION SYSTEM AND RECORDING MEDIUM HAVING RECORDED PROGRAM FOR CARRYING OUT COMMUNICATION METHOD

The present invention relates to communication method and device in a communication system and a recording medium having recorded thereon a program for carrying out the communication method.

With the development of communication techniques, wired and wireless communication devices have been widely used and users of the communication devices have wanted to be provided with stable and secure data transmitting and receiving services at any place at any time. The processes of transmitting data between the communication devices by communication layers will be described now in brief.

The communication generally mean some layers of an open system interconnection (hereinafter, referred to as “OSI”) reference model. The OSI reference model is a communication-relating standard model established to smoothly connect different types of communication devices to each other and is generally classified into seven layers.

The seven layers of the OSI reference model include includes layer 1 (physical layer), layer 2 (data link layer), layer 3 (network layer), layer 4 (transport layer), layer 5 (session layer), layer 6 (presentation layer), and layer 7 (application layer). The functions of the layers will be described in brief as follows.

Layer 1 (physical layer) determines what electric signal should be used to transmit a bit stream sent from a higher layer through a transmission medium. Layer 2 (data link layer) takes charge of the transmission of a data block including data bits of a signal level and serves to solve a synchronization problem relating to the start and end of the data block and an error problem relating to detection and correction of an error. Layer 3 (network layer) constitutes a logical link not shown between a transmission party and a reception party and serves to divide data into packet units, to transmit and then combine the divided packet units, and to provide a routing function of searching for the optimal path for transmitting the packets. Layer 4 (transport layer) sets up and maintains links between users or between computers and takes charge of the logical stabilization of the transmitting and receiving systems and the uniform provision of services. Layer 5 (session layer) sets up a session and provides a synchronization function so as to smooth a sequential flow of conversations. Layer 6 (presentation layer) handles methods of presenting data and provides a standard interface permitting different data presentations. Layer 7 (application layer) which is the highest layer serves as a window for allowing a user’s application program to access network environments.

The transmission of data between the seven layers of the OSI reference model will be described now in brief. A packet generated in layer 7 (application layer) is sent to layer 4 (transport layer) through layer 6 (presentation layer) and layer 5 (session layer). Layer 4 (transport layer) divides the data sent from the session layer into segments, numbers the segments, adds an error detection code thereto, and controls the communication flow. Layer 3 (network layer) performs a routing function of searching for the optimal path for transmission of the packet to a destination. Layer 2 (data link layer) solves the synchronization problem and the error problem and sends the packet to layer 1. Layer 1 (physical layer) sends the packet to the destination in a wired or wireless manner.

In transmitting data by the above-mentioned processes, a protocol corresponding to layer 2 divides data received from a layer equal to or higher than layer 3, transmits the divided data to a modem, combines the data received from the modem, and sends the combined data to the higher layer. That is, the protocol corresponding to layer 2 serves to process the data received from the higher layer and to send the processed data to a lower layer, and also serves to process the data from the lower layer and to send the processed data to the higher layer.

In current communication environments, data as well as voice should be transmitted. A representative communication system is a VoIP (Voice over Internet Protocol) system using the Internet. In the VoIP, from viewpoint of the data link layer, the data to be transmitted by the communication system is data corresponding to an IP format.

In such a communication system, a single CPU plays a role of the protocol corresponding to layer 2 by software. However, under the communication environments in which the data is transmitted, users want to transmit and receive the data at a higher speed and the amount of data to be transmitted and received increases. Therefore, the capability of a single CPU gets close to the limit.

Fifty percents or more of the IP data to be transmitted and received in the VoIP is information on the header and the other is information on voice or data desired by the users. Accordingly, there is a need for solving such a problem.

The present invention is to provide communication method and device in a communication system, which can allow maintaining a high processing speed by minimizing the movement of data between memories and can easily cope with a later change in information to optimize the usage of the memory by storing original data, when layer 2 processes data sent from a higher layer, and a program for carrying out the communication method.

And the present invention is to provide communication method and device in a communication system, which can transmit data at a high speed by allowing a transmission party to separate and compress an IP header and allowing a reception party to reconstruct and combine the compressed IP header, and a program for carrying out the communication method.

Other goals of the invention will be easily understood from the following description.

According to an aspect of the invention, there are provided a method of converting transmitted data in a communication system, a method of converting received data in a communication system, and a recording medium having recorded thereon a program for carrying out the methods.

According to an embodiment of the invention, there is provided a method of converting data, including the steps of: (a) receiving a higher-layer header separated from one or more layer 3 PDUs (Protocol Data Units); (b) compressing the higher-layer header; (c) receiving location information on a location in a transmitted data storage unit in which layer 3 data of the one or more layer 3 PDUs from which the higher-layer header is separated is stored; (d) performing an encrypting operation using the location information on the location at which the one or more layer 3 data is stored and the compressed one or more higher-layer headers corresponding to the location information; and (e) generating and outputting a transmission block by adding a layer 2 header to a transmission unit packet generated by the encrypting operation. Here, the layer 2 is a data link layer.

The higher-layer header in the step of (a) may have a predetermined size in the layer 3 PDU and is thus separated therefrom by a hardware logic.

The step of (b) may include compressing the higher-layer header using a ROHC (Robust Header Compression) method.

A step of dividing or combining the one or more layer 3 data to generate the transmission unit packet with the predetermined size of the transmission block may be performed before the step of (d).

The output transmission block may be stored in a transmitting memory in a data transmitting unit.

The step of (d) may be performed when a transmission interrupt from a data transmitting unit is sensed.

The step of (b) and the step of (c) may be simultaneously performed.

The layer 2 header may include one or more of a header for repetition check, a header for retransmission, a header for information on the division or combination of the layer 3 PDU, and a header for medium access control.

According to another embodiment of the invention, there is provided a method of converting data received by a terminal device through a network, including the steps of: (a) receiving location information on locations in a received data memory in which one or more compressed higher-layer headers and one or more layer 3 data, which are obtained by decrypting a transmission unit packet of a transmission block which is received through the network and from which the layer 2 header is separated, are stored; (b) decompressing the higher-layer header; (c) generating a layer 3 PDU (Protocol Data Unit) in which the decompressed higher-layer header and the layer 3 data are combined using the location information on the locations in which the decompressed higher-layer header and the layer 3 data corresponding thereto are stored; and (d) notifying a control layer of the receipt of the layer 3 PDU, wherein the layer 2 is a data link layer.

The step of (c) may include the steps of: determining whether the layer 3 data decrypted in the step of (a) is complete enough to reconstruct the layer 3 PDU; re-performing the step of (a) on a transmission block subsequently received through the network when the layer 3 data is not complete; and generating a complete layer 3 data using incomplete two or more layer 3 data on the basis of the layer 2 header.

According to another aspect of the invention, there are provided a device for converting transmitted data and a device or converting received data in a communication system.

According to an embodiment of the invention, there is provided a device for converting data to be transmitted through a network, including: a header separating unit separating one or more layer 3 PDUs (Protocol Data Units) into a higher-layer header and layer 3 data; a header compressing unit compressing the separated higher-layer header; a transmitted data storage unit storing the separated layer 3 header; a layer 2 function processing unit managing location information on a location in the transmitted data storage unit in which the layer 3 data is stored; an encryption unit encrypting the one or more higher-layer header compressed by the header compressing unit and the one or more layer 3 data read from the transmitted data storage unit on the basis of the location information received from the layer 2 function processing unit to correspond to the one or more higher-layer header and generating a transmission unit packet; a layer 2 control information processing unit generating a layer 2 header to be added to the transmission unit packet; and a transmission block generating and outputting unit generating a transmission block by adding the layer 2 header to the transmission unit packet, wherein the layer 2 is a data link layer.

The header separating unit may be embodied by a hardware logic which separates the higher-layer header using the fact that the higher-layer header has a predetermined size in the layer 3 PDU.

The header compressing unit may compress the higher-layer header using a ROHC (Robust Header Compression) method.

The layer 2 function processing unit may divide or combine the one or more layer 3 data to generate the transmission unit packet with the predetermined size of the transmission block.

The encryption unit may perform its encrypting operation when a transmission interrupt from a data transmitting unit is sensed.

According to another embodiment of the invention, there is provided a device for converting data received through a network, including: a transmission block separating unit separating a transmission block received through the network into a layer 2 header and a transmission unit packet; a decryption unit decrypting the transmission unit packet into one or more compressed higher-layer headers and one or more layer 3 data; a received data storage unit storing the decrypted layer 3 data; a header decompressing unit decompressing the decrypted compressed higher-layer header; a header combining unit combining the layer 3 data with the higher-layer header decompressed by the header decompressing unit to generate a layer 3 PDU (Protocol Data Unit); and a higher layer processing unit notifying a control layer of the receipt of the layer 3 PDU, wherein the layer 2 is a data link layer.

The device for converting the received data may further include a layer 2 function processing unit generating a complete layer 3 data using two or more incomplete layer 3 data. Here, the layer 2 function processing unit may generate a complete layer 3 data using another incomplete layer 3 data decrypted from a transmission block subsequently through the network when one or more incomplete layer 3 data exists.

Other aspects, features, and advantages of the invention will be clearly understood from the accompanying drawings, the appended claims, and the below detailed description.

In the communication method and device in a communication system and the program for carrying out the communication method, it is possible to allow maintaining a high processing speed by minimizing the movement of data between memories and to easily cope with a later change in information so as to optimize the usage of the memory by storing original data, when layer 2 processes data sent from a higher layer.

It is also possible to efficiently transmit data at a high speed by allowing a transmission party to separate and compress an IP header and allowing a reception party to reconstruct and combine the compressed IP header, and a program for carrying out the communication method.

FIG. 1 is a diagram schematically illustrating a communication system according to an embodiment of the invention.

FIG. 2 is a diagram illustrating the configuration of a transmitted data converting unit according to an embodiment of the invention.

FIG. 3 is a flowchart illustrating the flow of processes of converting data in the transmitted data converting unit according to an embodiment of the invention.

FIG. 4 is a diagram illustrating the configuration of a received data converting unit according to an embodiment of the invention.

FIG. 5 is a flowchart illustrating the flow of processes of converting data in the received data converting unit according to an embodiment of the invention.

The above-mentioned goals, features, and advantages of the invention will be apparent from the following detailed description with reference to the accompanying drawings.

The invention can be variously modified in various forms and specific embodiments will be described and shown in the drawings. However, the embodiments are not intended to limit the invention, but it should be understood that the invention includes all the modifications, equivalents, and replacements belonging to the spirit and the technical scope of the invention. When it is determined that detailed description of known techniques associated with the invention makes the gist of the invention obscure, the detailed description will be omitted.

Terms such as “first” and “second” can be used to describe various elements, but the elements are not limited to the terms. The terms are used only to distinguish one element from another element. For example, without departing from the scope of the invention, a first element may be named a second element and the second element may be named the first element similarly. The term, “and/or”, includes a combination of plural elements or any one of the plural elements.

If it is mentioned that an element is “connected to” or “coupled to” another element, it should be understood that still another element may be interposed therebetween, as well as that the element may be connected or coupled directly to another element. On the contrary, if it is mentioned that an element is “connected directly to” or “coupled directly to” another element, it should be understood that still another element is not interposed therebetween.

The terms used in the following description are used to merely describe specific embodiments, but are not intended to limit the invention. An expression of the singular number includes an expression of the plural number, so long as it is clearly read differently. The terms such as “include” and “have” are intended to indicate that features, numbers, steps, operations, elements, components, or combinations thereof used in the following description exist and it should be thus understood that the possibility of existence or addition of one or more different features, numbers, steps, operations, elements, components, or combinations thereof is not excluded.

So long as they are not defined differently, all the terms used therein, which include technical or scientific terms, have the same meanings as generally understood by those skilled in the art. The terms defined in dictionaries used in general should be analyzed to have the same meaning as in the contexts of the related art, but the terms should not be analyzed ideal or excessively formal.

Hereinafter, exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings. Like or corresponding elements are referenced by like reference numerals regardless of the drawing number and repeated description thereof is omitted.

The exemplary embodiments of the invention will be described now in detail with reference to the accompanying drawings.

In describing the embodiments of the invention by the use of layer names, layer 1 corresponds to the layer 1 (physical layer) of the OSI seven layers and layer 2 corresponds to the layer 2 (data link layer) of the OSI seven layers. The layer 2 further performs a division and combination function depending on a transmission block. Layer 3 corresponds to the third or higher layer (that is, the layer 3 (network layer), the layer 4 (transport layer), the layer 5 (session layer), the layer 6 (presentation layer), and the layer 7 (application layer)) out of the OSI seven layers and may be called a control layer or a higher layer.

FIG. 1 is a diagram schematically illustrating a communication system according to an embodiment of the invention. FIG. 2 is a diagram illustrating the configuration of a transmitted data converting unit according to an embodiment of the invention. FIG. 3 is a flowchart illustrating the flow of processes of converting data in the transmitted data converting unit according to an embodiment of the invention.

A transmitting terminal 100 and a receiving terminal 135 transmitting and receiving data through a network are shown in FIG. 1.

The transmitting terminal 100 includes a data output unit 110, a transmitted data converting unit 120, and a data transmitting unit 130. The receiving terminal 135 includes a data receiving unit 140, a received data converting unit 150, and a data input unit 160. In addition, the transmitting terminal 100 and the receiving terminal 135 may further include elements such as an input unit, a display unit, and a control unit depending on their functions, which do not relate directly to the gist of the invention and thus will not be described.

As shown in the drawing, the transmitted data converting unit 120 is disposed between the data output unit 110 for a higher layer (layer 3 or higher layer) and the data transmitting unit 130 transmitting data through the network. Similarly, the received data converting unit 150 is disposed between the data input unit 160 for a higher layer (layer 3 or higher layer) and the data receiving unit 140 receiving data through the network. Here, the data transmitting unit 130 and/or the data receiving unit 140 may be, for example, a modem.

The configuration and the processing operation of the transmitted data converting unit 120 will be described now with reference to FIGS. 2 and 3. As described below, the transmitted data converting unit 120 is located to operate in layer 2 and serves to receive data from layer 3 (or named control layer or higher layer, which is true in the following description) and to convert the received data so as to be transmitted via the data transmitting unit 130. The received data converting unit 150 is also located to operate in layer 2 and serves to convert the data received by the data receiving unit 140 and to send the converted data to layer 3.

That is, in the transmitted data converting unit 120 in this embodiment has a feature of encrypting and outputting only a part requiring the encryption just before data is sent from layer 2 to layer 1, similarly in encrypting a layer 3 PDU and encrypting a layer 2 PDU. An example where the layer 3 PDU is encrypted and output will be described now.

Referring to FIG. 2, the transmitted data converting unit 120 includes a header separating unit 210, a header compressing unit 220, a transmitted data storage unit 230, a location storage unit 240, a higher layer processing unit 250, a layer 2 function processing unit 260, a layer 2 control information processing unit 270, an encryption unit 280, and a transmission block generating unit 290. Some of the shown elements may be omitted or plural elements may be combined into one element. One or more elements may be embodied in the form of a software program.

The header separating unit 210 receives a layer 3 PDU (also referred to “layer 3 PDU”, “control-layer PDU”, or “higher-layer PDU”, or “packet”) from a higher layer, separates the received layer 3 PDU into a header and layer 3layer 3 data, stores the separated layer 3 data in the transmitted data storage unit 230, and provides the separated header to the header compressing unit 220. Here, the layer 3 PDU may be data having, for example, an IP (Internet Protocol).

The IP data is separated into a header and data and is classified into IPv4 and IPv6. In IPv4, the size of the header can be expressed by the first byte and is 20 to 60 bytes. In IPv6, the header has a constant size of 40 bytes.

Therefore, the header separating unit 210 can easily separate the header from the layer 3 PDU received from the higher layer using the fact that the size of the header is constant in the device embodied by hardware logics and send the separated header to the header compressing unit 220.

The header compressing unit 220 receives and compresses the header separated by the header separating unit 210. The header compressing unit 220 serves to compress the received header in a desired format and can be embodied by hardware logics or a software program. The header compressing unit 220 can perform the compressing operation using, for example, an ROHC (Robust Header Compression) method. Various other compression methods may be used to compress the header and the invention can be applied to compression techniques to be developed in the future.

The header compression enables the data transmitting unit 130 to include a relatively great amount of layer 3 data in the transmission unit packet to be transmitted by compressing the header greatly occupying the layer 3 PDU. As a result, it is possible to construct faster wireless communication environments and communication environments resistant to errors.

The transmitted data storage unit 230 is a space storing the layer 3 data other than the header separated by the header separating unit 210. The transmitted data storage unit 230 may be a physical memory such as a DRAM (Dynamic Random Access memory) and an SRAM (Static Random Access Memory).

The transmitted data storage unit 230 can easily cope with the re-transmission by maintaining the storage state of the stored layer 3 data in layer 2. However, the stored layer 3 data may be deleted as needed (for example, when an acknowledgement is received from the receiving terminal 135) so as to manage the storage space to be utilized. By allowing a processing element to access the received address and to utilize the data without moving or copying the layer 3 data stored in the transmitted data storage unit 230 to another storage unit or memory, it is possible to process data at a high speed.

The location storage unit 240 stores location information on the location where data is stored in the transmitted data storage unit 210. The location information stored in the location storage unit 240 may be information analyzed by the higher layer processing unit 250. The location information includes one or more an address in which the corresponding data is stored in the transmitted data storage unit 230 and the size of the data.

Here, actual data is stored in the transmitted data storage unit 230 and the location storage unit 240 manages the storage location of the actual data. In general, when it is intended to convert the higher-layer PDU in layer 2 and to transmit the converted higher-layer PDU to the data transmitting unit 130, the software process thereof takes much time due to the great amount of the higher-layer PDU. Accordingly, it is possible to reduce the time by the hardware process.

The higher layer processing unit 250 supports the functions such as mobility management, transmission control, and session management supported by the higher layer, and manages various parameters for controlling the second or lower layer. For example, the higher layer processing unit 250 can perform maintenance and management functions of an encrypting algorithm to be used, key values, and various functions supported by layer 2.

The layer 2 function processing unit 260 performs functions such as data PDU division/combination, retransmission control using an ARQ (Automatic Retransmission Request), an HARQ (Hybrid ARQ), and the like, and medium access control for managing physical layer resources.

The PDU division/combination performed by the layer 2 function processing unit 260 will be described now. The transmissible resources (for example, a path for communication) are allocated to layer 2 from layer 3 as a higher layer, but the size of the layer 3 PDU stored in the header separating unit 210 may be different from the size of the allocated resources. Therefore, the layer 2 function processing unit 260 can divide and/or combine the data stored in the transmitted data storage unit 230 into a proper size so as to transmit the maximum-sized data using the allocated resources. As described later with reference to the drawings, the layer 2 function processing unit 240 included in the received data converting unit 150 of the receiving terminal 135 performs a division and/or combination process to reconstruct the layer 3 PDU with the original size from the received data.

The retransmission control performed by the layer 2 function processing unit 260 will be described now. The data transmitting method in layer 2 includes three modes of a non-controlled mode, a controlled mode, and a controlled and acknowledged mode. The ARQ is an algorithm for defining an acknowledge method used in the controlled and acknowledged mode, in which the receiving terminal 135 having received specific data from the transmitting terminal 100 decodes the received data and returns an ACK message to the transmitting terminal 100. In this case, when the ACK message is not received in a predetermined time after the transmission of data or a data-reception error message (NACK message) is received, the data should be retransmitted. On the contrary, the HARQ is an algorithm for compensating for the disadvantage of the ARQ, in which the data to be retransmitted is not discarded but stored so as to help reconstruct the retransmitted data. For example, when the cyclic redundancy check (CRC) algorithm fails at the time of first receiving certain data and thus sends a NACK message, the receiving party does not discard but stores the data. Then, when the same data is received, the receiving party helps reconstruct the data using the first received data depending on the result of the cyclic redundancy check. Therefore, when it also fails to reconstruct the secondly received data, it is possible to reduce the number of re-transmission times by reconstructing the original data using the first received data instead of sending the NACK message to request for the re-transmission of the data.

The medium access control for physical layer resource management performed by the layer 2 function processing unit 240 means a scheduling and multiplexing function for efficiently using the allocated physical resources. This is intended to transmit and receive data with the maximum size suitable for the allocated physical resources, which is the ultimate function of layer 2.

The layer 2 control information processing unit 270 generates layer 2 header information. Here, the generated layer 2 header is header information of the transmission unit packet and is intended to transmit the transmission unit packet, which is obtained by combining and/or dividing a PDU so as to correspond to the transmission size, at a time for the purpose of efficient use of resources. Hereinafter, the header information may be called bundle header.

The bundle header can be generated to include information used to perform the layer 2 functions and can include, for example, one or more of a first header for redundancy check, a second header for retransmission, a third header for the information for dividing/combining the layer 3 PDU, and a fourth header for the information on the medium access control. The first header can allow determining the redundant arrival when the same number arrives, by sequentially increasing the sequence number or the like depending on the input data. The second header includes a re-transmission number, an acknowledge message of ACK/NACK, or the like. The re-transmission number is sequentially increased every transmission. Particularly, when the reception party requests for re-transmission of a specific number or the ACK message is not received from the reception party for a predetermined time, data corresponding to the specific number can be together transmitted. The third header is used to transmit information necessary for the reception party’s analysis of the division or combination performed in layer 2 of the transmission party. The fourth header includes information necessary for scheduling mediums for multiplexing. That is, the fourth header is used to express what transmission data is allocated to the current resources.

The layer 2 control information processing unit 270 combines one or more of the first header, the second header, the third header, and the fourth header to match with a protocol format and generates a bundle header which is transmitted to the transmitting memory 200 along with the data stored in the transmitted data storage unit 230. Preferably, the layer 2 control information processing unit 270 necessarily includes the third header for the information on the division/combination of a layer 3 PDU and generates control elements for transmitting the information necessary for the allocation of resources. This is because a process of combining and/or dividing several layer 3 data and inserting the combined and/or divided data into the transmission block with a predetermined size is necessary for utilizing the defined resources to the maximum.

The encryption unit 280 receives an input data stream, a key value used for the encryption, a sequence number, and the like and generates an output data stream as the encryption result. The key value and the sequence number are managed by one or more of the layer 2 function processing unit 260 and the layer 2 control information processing unit 270 and are provided to the encryption unit 280 as input variables when the encryption unit 280 encrypts the layer 3 data or the transmission unit packet formed by combing and/or dividing the layer 3 data so as to match with the transmission size. The key value can be received and stored in advance by the signaling of the higher layer before the encryption and the sequence number can be changed to a new value for each input data. The key value or the like may be shared by the transmitting terminal 100 and the receiving terminal 135. When the key value is not shared, the key value may be transmitted and received as separate data therebetween. The input data stream includes one or more headers compressed by the header compressing unit 220 and one or more layer 3 headers stored in the transmitted data storage unit 230.

The transmission block generating unit 290 generates a transmission block by combining the bundle header generated by the layer 2 control information processing unit 270 and the layer 3 data or the transmission unit packet encrypted by the encryption unit 280. When the generation of the transmission block is carried out by the encryption unit 280, the transmission block generating unit 290 may be omitted. The generated transmission block is stored in the transmitting memory 200 so as to allow transmitting data via the data transmitting unit 130. The transmitting memory 200 may be included in the transmitted data converting unit 120 or may be included in the data transmitting unit 130. The transmission block generating unit 290 may be included in the data transmitting unit 130.

In this embodiment, elements for performing operations being simple but requiring relatively much time may be embodied by hardware and elements having many logics and changes may be embodied by software. For example, the header separating unit 210, the transmitted data storage unit 230, the encryption unit 280, and the transmission block generating unit 290 may be embodied by hardware logics and the high layer processing unit 250, the layer 2 function processing unit 260, the layer 2 control information processing unit 270, and the location storage unit 240 may be embodied by software programs. The header compressing unit 220 may be embodied by hardware logics or software programs as described above.

The processing operation of the transmitted data converting unit 120 will be described now with reference to FIG. 3.

Referring to FIG. 3, the header separating unit 210 separates the layer 3 PDU received from a higher layer into a header and layer 3 data in step 310. The separation of the header can be carried out in hardware using the fact that the size of the header is constant.

In step 320, the header compressing unit 220 compresses the header separated by the header separating unit 210 using a predetermined compression method. Then, the header separating unit 210 stores the separated layer 3 data in the transmitted data storage unit 230. The compression of the header by the header compressing unit 220 and the storage of the layer 3 data of the header separating unit 210 may be carried out at the same time or may be sequentially or independently depending on the sequence.

In step 330, the layer 2 function processing unit 260 divides and/or combines the layer 3 data stored in the transmitted data storage unit 230 so as to match with the transmission size. The information (including location, size, and the like) on the space for the divided and/or combined layer 3 data is stored in the location storage unit 240. The layer 2 function processing unit 260 can access the location storage unit 240 to recognize the corresponding information or can be provided with the corresponding information from the higher layer processing unit 250.

In step 340, the layer 2 control information processing unit 270 generates a layer 2 header. The operation of the layer 2 control information processing unit 270 may be controlled by the layer 2 function processing unit 260. The layer 2 header includes a header for the information on the division/combination of the layer 3 PDU and control information on the allocation of resources.

In step 350, the layer 2 function processing unit 260 knows that a transmission interrupt is generated from the data transmitting unit 130. The transmission interrupt serves to notify the transmitted data converting unit 120 of the time when the transmission block can be transmitted from the data transmitting unit 130.

When the transmission interrupt is not generated, the processes (steps 310 to 340) on the layer 3 PDUs subsequently received from the high layer are repeated from step 310.

On the contrary, when the transmission interrupt is generated, the layer 2 control information processing unit 270 sends the information on the storage location of the input data to be encrypted, the compressed header sent from the header compressing unit 220, the key value to be used for encryption, and the sequence number to the encryption unit 280 in step 360. The input data includes one or more layer 3 data stored in the transmitted data storage unit 230.

In step 370, the encryption unit 280 encrypts the input data using one or more input data stored at the location of the transmitted data storage unit 230 corresponding to the information (including the address of the input data and the size of the input data) on the received storage location, one or more compressed headers corresponding thereto, the key value, and the sequence number.

In step 380, the transmission block generating unit 290 generates a transmission block by adding the layer 2 header (that is, the bundle header) generated by the layer 2 control information processing unit 270 to the data encrypted by the encryption unit 280. Then, the transmission block generating unit 290 stores the generated transmission block at a specific address of the transmitting memory 200 corresponding to the output location received from the layer 2 control information processing unit 270.

Thereafter, the data transmitting unit 130 transmits the transmission block stored in the transmitting memory 200 to the receiving terminal 135 through the network.

FIG. 4 is a diagram illustrating the configuration of the received data converting unit according to an embodiment of the invention and FIG. 5 is a flowchart illustrating the flow of processes in the received data converting unit according to an embodiment of the invention.

Referring to FIG. 4, the received data converting unit 150 includes a header combining unit 490, a header decompressing unit 480, a received data storage unit 470, a location storage unit 460, a higher layer processing unit 450, a layer 2 function processing unit 440, a layer 2 control information processing unit 430, a decryption unit 420, and a transmission block separating unit 410. Some of the shown elements may be omitted or plural elements may be combined into one element. One or more elements may be embodied by software. As described below, the functions of the elements of the received data converting unit 150 are equal to or reverse to the functions of the elements of the above-mentioned transmitted data converting unit 120. Therefore, the received data converting unit 150 and the transmitted data converting unit 120 may be combined into one data converting unit and may be included in the transmitting terminal 100 or the receiving terminal 135.

The data receiving unit 140 stores the transmission block transmitted from the data transmitting unit 130 of the transmitting terminal 100 through the network in a receiving memory 400. The data receiving unit 140 notifies the received data converting unit 150 that the transmission block is stored in the receiving member 400 and provides information on the location in which the transmission block.

The transmission block separating unit 410 separates the bundle header from the transmission block read from the receiving memory 400 on the basis of the information on the location. As described above, the bundle header includes the re-transmission header for re-transmission of each transmitted PDU, and the re-transmission header includes information (including one or more of location, size, and type) on one or more layer 3 PDUs included in the transmission unit packet.

The decryption unit 420 decrypts the encrypted transmission unit packet from which the bundle header has been separated by the transmission block separating unit 410 using the key value and the like predetermined or received from the transmitting terminal 100. The decrypted layer 3 data is stored in the received data storage unit 470 and the compressed header is provided to the header decompressing unit 480.

The received data storage unit 470 stores the layer 3 data and the compressed header, and can provide the compressed header to the header decompressing unit 480. The received data storage unit 470 may be a physical memory such as a DRAM and an SRAM.

The layer 2 control information processing unit 430 receives the notification on the reception of the transmission block from the data receiving unit 140 and separates the control information and the data in the receiving memory 400 with reference to the information on the layer 2 bundle header separated by the transmission block separating unit 410. Here, the data reception notification can include information (address information) on the location where the received transmission block is stored in the receiving memory 400.

The layer 2 control information processing unit 430 reads the address information on the location where the encrypted transmission unit packet is stored from the location storage unit 460 and provides the read address information to the decryption unit 420 so as to allow the decryption unit 420 to decrypt the encrypted transmission unit packet. In this case, the information on the location in the received data storage unit 470 where the data decrypted by the decryption unit 420 will be stored may be provided together.

When a layer 3 data is not completely constructed by the data obtained by decrypting the data included in an encrypted transmission unit packet, the layer 2 function processing unit 440 can construct one complete layer 3 data using the data obtained by decrypting the data included in the transmission unit packet received thereafter. This is because the transmitting terminal 100 divides/combines the layer 3 data to construct the transmission unit packet. When the receiving terminal 135 constructs the layer 3 data, the divided pieces can be recognized using the header for the information on the division/combination of the layer 3 data, which is included in the bundle header.

The higher layer processing unit 450 supports the functions such as mobility management, transmission control, and session management of the third or higher layer, and manages various parameters for controlling the second or lower layer. For example, the higher layer processing unit 450 can perform a maintenance and management function of the decrypting algorithms and key values to be used and a control and management function of various functions supported by layer 2.

The location storage unit 460 stores one or more of the information, that is, the address information and the size information, on the storage location of the transmission unit packet in the receiving memory 400.

The header decompressing unit 480 decompresses the header compressed by the header compressing unit 220 of the transmitted data converting unit 120 and sends the decompressed header to the header combining unit 490. The compression and decompression of a header can employ, for example, an ROHC method.

The header combining unit 490 combines the header decompressed by the header decompressing unit 480 with the layer 3 data stored in the received data storage unit 470 to generate a complete layer 3 PDU.

In this embodiment, elements for performing operations being simple but requiring relatively much time may be embodied by hardware and elements having many logics and changes may be embodied by software. For example, the header combining unit 490, the received data storage unit 470, the decryption unit 420, and the transmission block separating unit 410 may be embodied by hardware logics and the high layer processing unit 450, the layer 2 function processing unit 440, the layer 2 control information processing unit 430, and the location storage unit 460 may be embodied by software programs. The header decompressing unit 480 may be embodied by hardware logics or software programs.

The processing operation of the received data converting unit 150 will be described now with reference to FIG. 5. The received data converting unit 150 performs its operations in the order reverse to the above-mentioned operations of the transmitted data converting unit 120.

In step 510, a transmission block received from the transmitting terminal 100 through the network is stored in the receiving memory 400. When the transmission block is received and stored, the data receiving unit 140 notifies the layer 2 control information processing unit 430 of the receipt of the transmission block. At this time, the data receiving unit 140 can transmit the information on the location in the receiving memory 400 in which the transmission block is stored together.

In step 520, the transmission block separating unit 410 separates the bundle header (layer 2 header) from the transmission block.

In step 530, the layer 2 control information processing unit 430 notifies the decryption unit 420 of the storage location of the transmission block packet read from the location storage unit 460 and the storage location in the received data storage unit 470 where the decrypted layer 3 data will be stored. The separated bundle header is sent to the layer 2 control information processing unit 430.

In step 540, the decryption unit 420 decrypts the transmission unit packet stored in the receiving memory 400 using the key value and the like predetermined or received from the transmitting terminal 100. The decrypted compressed header is sent to the decompression unit 480 and the decrypted layer 3 data is stored in the received data storage unit 470.

In step 550, the layer 2 function processing unit 440 determines whether the data stored in the received data storage unit 470 is complete layer 3 data. This is to check whether the layer 3 PDU to be sent to the higher layer is complete and matched with the transmission sequence. The bundle header sent to the layer 2 control information processing unit 430 can be used for the check. For example, when the data is a divided piece of the layer 3 data and the other piece is not received yet, or when the sequence number is not matched, it can be determined that the data is not complete layer 3 data. The reason of receipt of the divided piece of the layer 3 data is that the transmitting terminal 100 can construct the transmission unit packet so as to include only a part of one layer 3 data.

When it is determined that the data is not the complete layer 3 data, the layer 2 function processing unit 440 determines whether all the required pieces are stored in the received data storage unit 470 and can be combined in step 560.

When it is determined that the pieces can be combined, the layer 2 function processing unit constructs the complete layer 3 data using the divided pieces in step 570. Although it is shown in the drawing that the process of step 570 is performed after the process of step 580, the process of step 550 may be performed after the process of step 570.

However, when the divided pieces are not stored yet in the received data storage unit 470, the subsequent process on the transmission block should be performed earlier and thus the process of step 510 is performed again.

When it is determined in step 550 that the data is the complete layer 3 data, the header combining unit 490 combines the layer 3 data stored in the received data storage unit 470 with the header decompressed by the header decompressing unit 480 to generate one layer 3 PDU in step 580.

Subsequently, in step 590, it is notified to the higher layer that the layer 3 PDU is received. Here, the notification may be carried out by one or more of the higher layer processing unit 450 and the layer 2 function processing unit 440.

It has been hitherto described that the layer 3 PDU is encrypted and output and the input transmission unit packet is decrypted to reconstruct the layer 3 PDU. However, whether the transmitted data converting unit 120 encodes the layer 3 PDU or the layer 2 PDU having been subjected to the division/combination and the addition of a header, it will be easily understood with reference to the embodiments of the invention that only the part requiring the encrypting is encrypted and output just before it goes from layer 2 to layer 1. Similarly, it will be easily understood that the received data converting unit 150 can perform the corresponding functions with the corresponding configuration.

The above-mentioned communication method in a communication system, that is, the data converting method in the transmitted data converting unit and the data converting method in the received data converting unit may be carried out in time series by a software program built in a terminal device. Codes and code segments of the program will be easily obtained by programmers skilled in the art. The program can be stored in a computer-readable recording medium and can be read and executed by a computer to embody the above-mentioned methods. The recording medium includes a magnetic recording medium, an optical recording medium, and a carrier wave medium.

Although the invention has been described with reference to the exemplary embodiments, it will be understood by those skilled in the art that the invention can be modified and changed in various forms without departing from the spirit and scope of the invention described in the appended claims.

Claims

A method of converting data which a terminal device should transmit through a network, the method comprising:

(a) receiving a higher-layer header separated from one or more layer 3 PDUs (Protocol Data Units);

(b) compressing the higher-layer header;

(c) receiving location information on a location in a transmitted data storage unit in which layer 3 data of the layer 3 PDUs from which the higher-layer header is separated is stored;

(d) performing an encrypting operation using the location information on the location at which the one or more layer 3 data is stored and the compressed one or more higher-layer headers corresponding to the location information; and

(e) generating and outputting a transmission block by adding a layer 2 header to a transmission unit packet generated by the encrypting operation,

wherein the layer 2 is a data link layer.
The method according to claim 1, wherein the higher-layer header in the step of (a) has a predetermined size in the layer 3 PDU and is separated therefrom by a hardware logic.
The method according to claim 1, wherein the step of (b) includes compressing the higher-layer header using a ROHC (Robust Header Compression) method.
The method according to claim 1, wherein a step of dividing or combining the one or more layer 3 data to generate the transmission unit packet with the predetermined size of the transmission block is performed before the step of (d).
The method according to claim 1, wherein the output transmission block is stored in a transmitting memory in a data transmitting unit.
The method according to claim 1, wherein the step of (d) is performed when a transmission interrupt from a data transmitting unit is sensed.
The method according to claim 1, wherein the step of (b) and the step of (c) are simultaneously performed.
The method according to claim 1, wherein the layer 2 header includes one or more of a header for repetition check, a header for retransmission, a header for information on the division or combination of the layer 3 PDU, and a header for medium access control.
A recording medium having recorded thereon a program which can be read by a digital processor and in which command words executable by the digital processor are materially described so as to carry out the method according to any one of claims 1 to 8.
A device for converting data to be transmitted through a network, comprising:

a header separating unit separating one or more layer 3 PDUs (Protocol Data Units) into a higher-layer header and layer 3 data;

a header compressing unit compressing the separated higher-layer header;

a transmitted data storage unit storing the separated layer 3 data;

a layer 2 function processing unit managing location information on a location in the transmitted data storage unit in which the layer 3 data is stored;

an encryption unit encrypting the one or more higher-layer header compressed by the header compressing unit and the one or more layer 3 data read from the transmitted data storage unit on the basis of the location information received from the layer 2 function processing unit to correspond to the one or more higher-layer header and generating a transmission unit packet;

a layer 2 control information processing unit generating a layer 2 header to be added to the transmission unit packet; and

a transmission block generating and outputting unit generating a transmission block by adding the layer 2 header to the transmission unit packet,

wherein the layer 2 is a data link layer.
The device according to claim 10, wherein the header separating unit is embodied by a hardware logic and separates the higher-layer header using the fact that the higher-layer header has a predetermined size in the layer 3 PDU.
The device according to claim 10, wherein the header compressing unit compresses the higher-layer header using a ROHC (Robust Header Compression) method.
The device according to claim 10, wherein the layer 2 function processing unit divides or combines the one or more layer 3 data to generate the transmission unit packet with the predetermined size of the transmission block.
The device according to claim 10, wherein the output transmission block is stored in a transmitting memory in a data transmitting unit.
The device according to claim 10, wherein the encryption unit performs its encrypting operation when a transmission interrupt from a data transmitting unit is sensed.
The device according to claim 10, wherein the layer 2 header includes one or more of a header for repetition check, a header for retransmission, a header for information on the division or combination of the layer 3 PDU, and a header for medium access control.
A method of converting data received by a terminal device through a network, the method comprising:

(a) receiving location information on locations in a received data memory in which one or more compressed higher-layer headers and one or more layer 3 data, which are obtained by decrypting a transmission unit packet of a transmission block which is received through the network and from which the layer 2 header is separated, are stored;

(b) decompressing the higher-layer header;

(c) generating a layer 3 PDU (Protocol Data Unit) in which the decompressed higher-layer header and the layer 3 data are combined using the location information on the locations in which the decompressed higher-layer header and the layer 3 data corresponding thereto are stored; and

(d) notifying a control layer of the receipt of the layer 3 PDU,

wherein the layer 2 is a data link layer.
The method according to claim 17, wherein the step of (c) includes:

determining whether the layer 3 data decrypted in the step of (a) is complete enough to reconstruct the layer 3 PDU;

re-performing the step of (a) on a transmission block subsequently received through the network when the layer 3 data is not complete; and

generating a complete layer 3 data using incomplete two or more layer 3 data on the basis of the layer 2 header.
A recording medium having recorded thereon a program which can be read by a digital processor and in which command words executable by the digital processor are materially described so as to carry out the method according to any one of claims 17 to 18.
A device for converting data received through a network, comprising:

a transmission block separating unit separating a transmission block received through the network into a layer 2 header and a transmission unit packet;

a decryption unit decrypting the transmission unit packet into one or more compressed higher-layer headers and one or more layer 3 data;

a received data storage unit storing the decrypted layer 3 data;

a header decompressing unit decompressing the decrypted compressed higher-layer header;

a header combining unit combining the layer 3 data with the higher-layer header decompressed by the header decompressing unit to generate a layer 3 PDU (Protocol Data Unit); and

a higher layer processing unit notifying a control layer of the receipt of the layer 3 PDU,

wherein the layer 2 is a data link layer.
The device according to claim 20, further comprising a layer 2 function processing unit generating a complete layer 3 data using two or more incomplete layer 3 data,

wherein the layer 2 function processing unit generates a complete layer 3 data using another incomplete layer 3 data decrypted from a transmission block subsequently through the network when one or more incomplete layer 3 data exists.