WO2008097001A1

WO2008097001A1 - Method and apparatus for transmitting/receiving variable-sized packet in a mobile communication system

Info

Publication number: WO2008097001A1
Application number: PCT/KR2008/000679
Authority: WO
Inventors: Soeng-Hun Kim; Youn-Hyoung Heo
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2007-02-05
Filing date: 2008-02-04
Publication date: 2008-08-14

Abstract

A method and apparatus for transmitting/receiving variable-sized packets in a mobile communication system. When transmission resources for a packet service are persistently allocated and a size of a Transport Block (TB) containing a packet is determined, a User Equipment (UE) notifies to a Node B the generation of a packet whose size exceeds a predetermined TB size containable in the TB, to request the Node B to temporarily increase the TB size of the TB.

Description

METHOD AND APPARATUS FOR TRANSMITTING/ RECEIVING VARIABLE-SIZED PACKET IN A MOBILE COMMUNICATION SYSTEM

Technical Field

[1] The present invention relates generally to a mobile communication system, and in particular, to a method and apparatus for transmitting/receiving variable- sized packets to efficiently support the service that uses persistent transmission resources. Background Art

[2] The Universal Mobile Telecommunication Service (UMTS) system is a 3-rd generation asynchronous mobile communication system that uses Wideband Code Division Multiple Access (W-CDMA) based on Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), both of which are European mobile communication systems.

[3] In 3-rd Generation Partnership Project (3GPP) in charge of UMTS standardization, discussions are being held on Long Term Evolution (LTE) as the next generation UMTS mobile communication system. LTE is a technology for realizing packet- switched communication at the high speed of about 100 Mbps, with the aim of commercialization as early as 2010. To this end, discussions are being held on several schemes: for example, one scheme of reducing the number of nodes located in a communication path by simplifying the network configuration, and another scheme of approximating wireless protocols as close as to the wireless channel.

[4] The next generation mobile communication system supports Node B scheduling in which a Node B, also known as 'base station', allocates transmission resources to a User Equipment (UE), also known as 'mobile station' or 'terminal', based on the wireless resource requirement and channel condition of the UE. The Node B scheduling, though it is efficient in the high-speed packet service, is not so efficient in the service such as Voice over Internet Protocol (VoIP), in which small-sized packets are periodically generated. Therefore, for VoIP, the next generation mobile communication system, such as LTE or 802.20, previously allocates predetermined transmission resources at predetermined intervals, and fixes a size of a Transport Block (TB), which is a packet of a Medium Access Control (MAC) layer, containing a VoIP packet therein, thereby avoiding the possible need for out-band signaling for size variation of the TB during VoIP packet transmission.

[5] FIG. 1 illustrates an exemplary operation of providing a VoIP service using persistent transmission resources and a semi-static TB size according to the prior art. [6] Referring to FIG. 1, in step 115, a UE 105 and a Node B I lO, which is a network entity, undergo a VoIP call setup process, and the Node B I lO determines persistent transmission resources (also called 'persistent resources' for short) to be allocated to the UE 105 and a semi- static TB size to be used by the UE 105, through a predetermined scheduling process. Thereafter, in step 120, the Node B I lO notifies the determined results to the UE 105. In step 125, the UE 105 includes a VoIP packet in a TB configured according to the semi-static TB size, and then transmits it over the persistent transmission resources.

[7] The persistent transmission resources and the semi-static TB size are continuously valid until they are replaced with other values by separate signaling. In other words, the UE 105 repeatedly performs the process of step 125 for every VoIP packet until the Node B I lO issues a separate command.

[8] The use of the persistent transmission resources and semi-static TB size by the Node

B has an advantage that there is no need to transmit separate control information, but has a possible problem that once a VoIP packet with a size uncontainable in the TB with the semi-static TB size is generated, its succeeding VoIP packets continuously undergo fragmented transmission.

[9] The VoIP packet has a variable size due to a header compression technique such as

Robust Header Compression (ROHC). In most cases, ROHC compresses an IP/User Datagram Protocol (UDP)/Real-Time Protocol (RTP) header with a 60-byte size into a 3 -byte header, and when there is an unexpected change in information on the IP/ UDP/RTP header, ROHC compresses the IP/UDP/RTP header into a header with a size of more than 3 bytes, for example, 4 to 15 bytes. When Adaptive Multi-Rate (AMR) 12.2 Kbps is considered as a standard, a size of a voice frame generated in a codec is constant at 32 bytes, so the VoIP packet has a size of about 35 to 47 bytes in the wireless protocol level. If the Node B I lO has set, in step 120, the semi-static TB size according to 35 bytes of the most-frequently generated VoIP packet size, a part of the large VoIP packet is contained in one TB and the remaining part is contained in the next TB during its transmission, because the VoIP packet with a size larger than 35 bytes cannot be contained in one TB.

[10] FIG. 2 illustrates the possible problems of the VoIP service according to the prior art.

[11] Referring to FIG. 2, when VoIP packets 205 and 215 with a 35-byte size occur, the packets 205 and 215 are contained in TBs 210 and 220 with a semi-static TB size m, and then transmitted over persistent transmission resources. However, if a VoIP packet 225 with a 36-byte size occurs, only 35 bytes of, or a part of, the VoIP packet 225 is transmitted in a TB 230 with the semi-static TB size m, and the remaining 1 byte of the VoIP packet 225 is transmitted in the next TB 240. Then, because the next TB 245 should also contain the next VoIP packets 235 and 250, only the leading 34 bytes 235 of the next VoIP packets 235 and 250 are transmitted over the TB 245, and again, the remaining 1 byte 250 of the VoIP packet 235 is transmitted in the next TB 245. The same problem may continue.

[12] Such problems may always occur unless the semi-static TB size is set according to the maximum size of the VoIP packet. However, if the semi-static TB size is set according to the maximum size, e.g., 47 bytes, of the VoIP packet to cope with the problems, a 12-byte space may be wasted by padding in most TBs, causing another inefficiency problem. Disclosure of Invention Technical Problem

[13] An aspect of the present invention is to address at least the problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method and apparatus in which a network entity temporarily changes a semi-static TB size when a packet untrans- mittable with the semi-static TB size occurs in a mobile communication system using persistent transmission resources.

[14] Another aspect of the present invention is to provide a method and apparatus of notifying occurrence of a packet untransmittable with a semi-static TB size to a network entity in a mobile communication system using persistent transmission resources. Technical Solution

[15] According to one aspect of the present invention, there is provided a method for transmitting variable- sized packets in a mobile communication system. The method includes, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB to the Node B; receiving a new TB size determined according to the size information from the Node B; and transmitting at least one following packet to the Node B according to the new TB size.

[16] According to another aspect of the present invention, there is provided a User

Equipment (UE) apparatus for transmitting variable- sized packets in a mobile communication system. The apparatus includes a controller for, when a packet can be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transceiver for transmitting one of the TBs to the Node B, and receiving a new TB size determined according to the size information from the Node B to provide the new TB size to the controller.

[17] According to further another aspect of the present invention, there is provided a method for receiving variable- sized packets in a mobile communication system. The method includes signaling a Transport Block (TB) size to a User Equipment (UE); upon receipt of a TB with the TB size from the UE, determining whether size information indicating a required TB size of the UE is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and transmitting a new TB size determined according to the size information to the UE; and receiving at least one following packet from the UE according to the new TB size.

[18] According to yet another aspect of the present invention, there is provided a Node B apparatus for receiving variable-sized packets in a mobile communication system. The apparatus includes a transceiver for receiving, from a User Equipment (UE), a Transport Block (TB) with a TB size signaled to the UE; and a controller for, when size information indicating a required TB size of the UE is included in the TB, extracting a fragmented part of a packet from the TB, transmitting a new TB size determined according to the size information to the UE by means of the transceiver, and controlling the transceiver to receive at least one following packet from the UE according to the new TB size.

[19] According to still another aspect of the present invention, there is provided a method for transmitting variable-sized packets in a mobile communication system. The method includes, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB to the Node B; and after a TB including the size information is successfully transmitted to the Node B, transmitting at least one following packet to the Node B according to the required TB size for at least one predetermined transmission time.

[20] According to still another aspect of the present invention, there is provided a User

Equipment (UE) apparatus for transmitting variable- sized packets in a mobile communication system. The apparatus includes a controller for, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transmission unit for transmitting one of the TBs to the Node B, and after a TB including the size information is successfully transmitted to the Node B, transmitting a TB including a next packet to the Node B according to the required TB size for at least one predetermined transmission time. [21] According to still another aspect of the present invention, there is provided a method for receiving variable- sized packets in a mobile communication system. The method includes signaling a Transport Block (TB) size to a User Equipment (UE); upon receipt of a TB with the TB size from the UE, determining whether size information indicating a required TB size of the UE is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and notifying to the UE the successful receipt of the TB including the size information; and receiving at least one next packet from the UE according to the required TB size.

[22] According to still another aspect of the present invention, there is provided a Node B apparatus for receiving variable-sized packets in a mobile communication system. The apparatus includes a reception unit for receiving, from a User Equipment (UE), a Transport Block (TB) with a TB size signaled to the UE; and a controller for, when size information indicating a required TB size of the UE is included in the TB, extracting a fragmented part of a packet from the TB, notifying to the UE the successful receipt of the TB including the size information, and controlling the reception unit to receive at least one next packet from the UE according to the required TB size.

[23] According to still another aspect of the present invention, there is provided a method for transmitting variable-sized packets in a mobile communication system. The method includes, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled to a User Equipment (UE) without being fragmented, including, in the TB with the TB size, size information indicating a next TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB to the UE; and after the TB including the size information is successfully transmitted to the UE, transmitting a next packet to the UE according to the next TB size for at least one predetermined transmission time.

[24] According to still another aspect of the present invention, there is provided a Node B apparatus for transmitting variable- sized packets in a mobile communication system. The apparatus includes a controller for, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled to a User Equipment (UE) without being fragmented, including, in the TB with the TB size, size information indicating a next TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transceiver for transmitting one of the TBs to the UE, and after the TB including the size information is successfully transmitted to the UE, transmitting a TB including a next packet to the UE according to the next TB size for at least one predetermined transmission time.

[25] According to still another aspect of the present invention, there is provided a method for receiving variable- sized packets in a mobile communication system. The method includes, upon receipt of a Transport Block (TB) with a TB size signaled by a Node B from the Node B, determining whether size information indicating a next TB size of the Node B is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and notifying to the Node B the successfully receipt of the TB including the size information; and receiving at least one next packet from the Node B according to the next TB size.

[26] According to still another aspect of the present invention, there is provided a User

Equipment (UE) apparatus for receiving variable-sized packets in a mobile communication system. The apparatus includes a reception unit for receiving a Transport Block (TB) with a TB size signaled by a Node B from the Node B; and a controller for, when size information indicating a next TB size of the Node B is included in the TB, extracting a fragmented part of a packet from the TB, notifying to the Node B the successfully receipt of the TB including the size information, and controlling the reception unit to receive at least one next packet from the Node B according to the next TB size.

[27] According to still another aspect of the present invention, there is provided a method for transmitting variable-sized packets in a mobile communication system. The method includes determining whether a packet generated in a logical channel in service is transmitted after being fragmented; and when the packet generated in the logical channel is transmitted after being fragmented, configuring a buffer status report message including a buffer status of the logical channel and transmitting the buffer status report message to a Node B, to request additional transmission resources for a remaining fragmented part of the packet of the logical channel.

[28] According to still another aspect of the present invention, there is provided a User

Equipment (UE) apparatus for transmitting variable- sized packets in a mobile communication system. The apparatus includes a controller for, when a packet generated in a logical channel in service is transmitted after being fragmented, configuring a buffer status report message including a buffer status of the logical channel to request additional transmission resources for a remaining fragmented part of the packet of the logical channel; and a transmission unit for transmitting the buffer status report message to a Node B.

Advantageous Effects

[29] As is apparent from the description, the present invention appropriately adjusts the

TB size, which is determined on a semi-static basis in the service using persistent transmission resources, thereby minimizing the waste of transmission resources in providing the VoIP service. Brief Description of the Drawings

[30] The above and other aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in con- junction with the accompanying drawings in which:

[31] FIG. 1 a flowchart illustrating an exemplary operation of providing a VoIP service using persistent transmission resources and a semi-static TB size according to the prior art;

[32] FIG. 2 is a diagram illustrating the possible problems of the VoIP service according to the prior art;

[33] FIG. 3 is a diagram illustrating a relationship between a VoIP packet and a TB;

[34] FIG. 4 is a diagram briefly illustrating the overall operation according to a preferred embodiment of the present invention;

[35] FIG. 5 is a diagram illustrating an exemplary structure of a MAC PDU in which a required TB size is contained according to a preferred embodiment of the present invention;

[36] FIG. 6 is a signaling flow illustrating the entire operation according to a first embodiment of the present invention;

[37] FIG. 7 is a flowchart illustrating a UE' s operation according to the first embodiment of the present invention;

[38] FIG. 8 is a flowchart illustrating a Node B's operation according to the first embodiment of the present invention;

[39] FIG. 9 is a signaling flow illustrating the entire operation according to a second embodiment of the present invention;

[40] FIG. 10 is a flowchart illustrating a UE's operation according to the second embodiment of the present invention;

[41] FIG. 11 is a flowchart illustrating a Node B's operation according to the second embodiment of the present invention;

[42] FIG. 12 is a signaling flow illustrating the entire operation according to a third embodiment of the present invention;

[43] FIG. 13 is a flowchart illustrating a UE's operation according to the third embodiment of the present invention;

[44] FIG. 14 is a flowchart illustrating a Node B's operation according to the third embodiment of the present invention;

[45] FIG. 15 is a flowchart illustrating a UE's operation according to a fourth embodiment of the present invention;

[46] FIG. 16 is a block diagram illustrating a UE apparatus according to a preferred embodiment of the present invention; and

[47] FIG. 17 is a block diagram illustrating a Node B apparatus according to a preferred embodiment of the present invention. Mode for the Invention [48] Preferred embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness.

[49] The gist of the present invention is to provide a service using persistent transmission resources in a mobile communication system, wherein when a packet uncontainable in a Transport Block (TB) with a preset size occurs at a User Equipment (UE), the UE notifies the occurrence to a scheduler of a Node B, which is a network entity. Then the Node B temporarily increases the TB size at the request of the UE. For example, in the situation where transmission resources for the VoIP service are persistently allocated and a size of the TB containing a VoIP packet is predetermined, when a size of a newly occurring VoIP packet exceeds the TB size, the UE notifies the occurrence of the (oversized) VoIP packet to the Node B to request a temporary increase in the TB size.

[50] Although a detailed description of the present invention will be made with reference to an LTE system based on the UMTS system, it would be obvious to those skilled in the art that the control message processing proposed by the present invention can be applied to other mobile communication systems having the similar technical background and channel format without departing from the spirit and scope of the invention as defined by the appended claims.

[51] A brief description will first be made of a relationship between the TB and the VoIP packet.

[52] Protocol layers, called Radio Link Control (RLC) and MAC layers, exist in LTE. The

RLC layer takes charge of an operation of framing a packet generated in an upper layer in an appropriate size, i.e., a function of fragmenting or concatenating an upper layer packet(s), and the packet delivered from the RLC layer to the MAC layer is called an RLC Protocol Data Unit (PDU). The MAC layer takes charge of a function of inserting RLC PDUs delivered from the RLC layer into a MAC PDU by means of multiplexing, and then transmitting the MAC PDU to the counterpart entity over a physical layer. The RLC PDU and the MAC PDU are generated by attaching a header of a corresponding protocol to their upper layer PDUs.

[53] FIG. 3 illustrates a relationship between a VoIP packet and a TB, both being applied to the present invention.

[54] Referring to FIG. 3, an RLC PDU 325 is generated by attaching RLC-specific header information (hereinafter referred to as an 'RLC header') 310, such as a sequence number, to an upper layer packet, e.g., VoIP packet 305, being input to the RLC layer. A TB or MAC PDU 320 is generated by attaching MAC-specific header information (hereinafter referred to as a 'MAC header') 315, such as multiplexing information, to the RLC PDU 325. [55] When only one VoIP packet is contained in a TB during its transmission, a size of the VoIP packet and a size of the TB have the following relationship.

[56] TB size = (MAC header size) + (RLC header size) + (VoIP packet size)

[57] Upon the start of the VoIP service, a Node B sets a TB size according to a size of a

VoIP packet expected to frequently occur. Herein, the TB size is a value obtained by adding a size of the MAC header and a size of the RLC header to the size of the VoIP packet expected to frequently occur, and has a semi-static characteristic.

[58] FIG. 4 briefly illustrates the overall operation according to a preferred embodiment of the present invention. It is assumed herein that a size of the VoIP packet expected to frequently occur is n bytes, and a TB size being set according thereto is (n + h) bytes, where h denotes sizes of the MAC header and the RLC header.

[59] Referring to FIG. 4, VoIP packets 405, 415 and 435 with an n-byte size, and a VoIP packet 425 with a size smaller than the n-byte size are fully contained in TBs 410, 420, 430 and 440 with an (n-ι-h)-byte TB size and transmitted at a time. However, as for the TB 430 in which the VoIP packet 425 with a size smaller than the n-byte size is contained, its remaining capacity is filled with padding bits.

[60] When a VoIP packet 445 whose size is greater than the n-byte size by a k-byte size occurs, a UE determines to fragment the VoIP packet 445 because it cannot include the VoIP packet 445 in an (n-ι-h)-byte TB 450 at a time. In this case, to minimize the possible fragmentation of the VoIP packet 445, the UE signals a required TB size 452 in preparation for the next transmission, to a Node B along with the VoIP packet 445. That is, the UE notifies the TB size suitable to transmit the remaining non-transmitted part of the VoIP packet 445 and the packet to be transmitted at the next transmission time all at once, to the Node B using the required TB size 452, thereby requesting the Node B to temporarily adjust the TB size.

[61] The UE calculates the required TB size using Equation (1).

[62] required TB size = (next VoIP packet size + h + s + k) bytes ... (1)

[63] In Equation (1), 'next VoIP packet size' denotes a size of a VoIP packet to be transmitted at the next transmission time. When a VoIP packet to be transmitted at the next transmission time exists in a transmission buffer at the time where the UE signals the required TB size, the UE uses a size of the buffered packet, and otherwise, the UE uses a size 'n' of the normal VoIP packet.

[64] 'h' denotes a size difference between the VoIP packet (405, 415, 425 or 435) and the

TB (410, 420, 430 or 440), and is a sum of a size of a MAC header 505 and a size of an RLC header 510. V denotes a size of an information field necessary for signaling the required TB size. A value of the V is determined according to the signaling scheme of the required TB size, and it is preferable to allow the V to have a small size, if possible. [65] FIG. 5 illustrates an exemplary structure of a MAC PDU in which a required TB size is contained according to a preferred embodiment of the present invention. As illustrated, the MAC PDU includes a MAC header 505, RLC headers 510 and 515, and a VoIP packet 520, and a required TB size can be defined as an RLC option header within, for example, the RLC headers 510 and 515. Then the required TB size 515 is attached to the back of the general RLC header information 510.

[66] A UE, after defining the required TB size 452 in this way, inserts size information indicating the required TB size 452 into the TB 450 in a predetermined manner before transmission. Therefore, only the leading (n - h) bytes rather than the entire bytes of the VoIP packet 445 are contained in the TB 450, and the remaining (k + h) bytes are stored in the transmission buffer.

[67] A Node B, upon receipt of the size information, resets the TB size for the next transmission time according to the required TB size, and if necessary, notifies the reset result to the UE to notify the change in the TB size.

[68] The UE configures a TB 460 by including therein all of the remaining non- transmitted (k+h) bytes and a new VoIP packet 455 according to the newly set TB size, and then transmits the TB 460.

[69] FIG. 6 is a signaling flow illustrating the entire operation of a UE and a Node B according to a first embodiment of the present invention.

[70] Referring to FIG. 6, in step 615, when a UE 605 and a Node B 610 perform a call setup process for the VoIP service, the Node B 610 signals persistent transmission resources and a TB size for the VoIP service to the UE 605.

[71] When a VoIP packet occurs at the UE 605, the UE 605 includes in step 620 the VoIP packet in a MAC PDU with the TB size, and transmits it over the persistent transmission resources. If an appropriate TB size has been defined in step 615, the frequently occurring VoIP packets are contained in a MAC PDU with the TB size, without being fragmented. The UE 605 repeats step 620 while the VoIP packets with a size containable in the MAC PDU with the TB size without being fragmented, occur. If a VoIP packet uncontainable in the MAC PDU with the TB size without being fragmented, i.e., a VoIP packet larger than the frequently occurring VoIP packets, occurs in step 625, the UE 605 includes, in step 630, size information indicating a required TB size in the MAC PDU, and includes a part fragmented from the VoIP packet in the remaining space except for the size information of the MAC PDU, before transmission. The required TB size is determined as a size suitable to transmit the remaining part fragmented from the VoIP packet and the next VoIP packet all at once.

[72] In step 635, the Node B 610 determines a size of the MAC PDU that the UE 605 will transmit next, depending on the required TB size indicated by the size information included in the MAC PDU, and signals the determined size to the UE 605. In this case, if the required TB size, i.e., the size of the MAC PDU that the UE 605 will transmit at the next transmission time, is too large to transmit the corresponding MAC PDU over the persistent transmission resources, the Node B 610 can temporarily allocate more transmission resources to the UE 605 in step 635.

[73] In step 640, the UE 605 configures a MAC PDU containing the remaining part fragmented from the VoIP packet and the next VoIP packet depending on the new TB size, and transmits the MAC PDU over the previously allocated or newly allocated transmission resources. The new TB size is determined to be equal to the required TB size transmitted by the UE 605, or determined depending on the required TB size.

[74] Generally, after the large-sized VoIP packet occurs, normal-sized VoIP packets occur, and when the UE 605 transmits the normal-sized VoIP packets in the new TB size set in step 635, more-than-necessary padding (over-padding) may occur. Therefore, after receiving the large VoIP packet, the Node B 610 switches to the original TB size. In this case, the Node B 610 can re-signal the original TB size. Alternatively, an agreement can be previously made between the Node B 610 and the UE 605 such that the new TB size is applied to transmission of only n (for example, n=l) MAC PDU(s), and then switched to the original TB size.

[75] FIG. 7 illustrates a UE' s operation according to the first embodiment of the present invention.

[76] Referring to FIG. 7, in step 705, the UE receives persistent transmission resources and a TB size to be used for the VoIP service in the uplink, signaled from a Node B. If the UE arrives at the transmission time for use of the persistent transmission resources in step 710, the UE proceeds to step 713 where it updates the TB size with the last received TB size-related value. If no new TB size has been signaled, the UE uses the intact TB size received in step 705, and if a new TB size has been signaled after step 705, the UE uses the new TB size.

[77] Thereafter, the UE determines in step 715 whether a desired transmission VoIP packet can be contained in a MAC PDU with the (updated) TB size without being fragmented. Assuming that the MAC PDU is generated by adding an H-byte overhead to the VoIP packet, if the TB size is greater than the size of the VoIP packet by H bytes or more, the UE proceeds to step 720, as the VoIP packet can be contained in the MAC PDU without being fragmented. However, if the TB size is not greater than the size of the VoIP packet by H bytes or more, the UE proceeds to step 725, because the VoIP packet should be fragmented.

[78] In step 720, the UE includes the VoIP packet in the MAC PDU with the TB size, and then proceeds to step 735 where it transmits the MAC PDU. Thereafter, the UE returns to step 710 to wait until the next transmission time where it will use the persistent transmission resources. [79] In step 725, the UE calculates a required TB size using Equation (1) described above.

In step 730, the UE includes size information indicating the required TB size in the MAC PDU with the TB size, and includes a first part fragmented from the VoIP packet in the remaining space. Thereafter, the UE transmits the MAC PDU in step 735, and then returns to step 710 to wait until the next transmission time where it will use the persistent transmission resources. The remaining part fragmented from the VoIP packet is transmitted on the next TB along with the next VoIP packet.

[80] FIG. 8 illustrates a Node B's operation according to the first embodiment of the present invention.

[81] Referring to FIG. 8, in step 805, the Node B signals persistent transmission resources and a TB size to be used for the VoIP service in the uplink, to a UE. If a MAC PDU is successfully received over the persistent transmission resources in step 810, the Node B proceeds to step 815 where it determines whether the received MAC PDU includes size information indicating a required TB size. If the size information is included, the Node B proceeds to step 825, and if the size information is not included, the Node B proceeds to step 820.

[82] In step 820, the Node B processes a MAC PDU received next, considering that a size of the MAC PDU to be received next over the persistent transmission resources is the original TB size set in step 805. However, in step 825, the Node B determines a new TB size for the MAC PDU received next depending on the required TB size, notifies the new TB size to the UE using an L1/L2 control channel, and then processes the MAC PDU received next using the new TB size.

[83] In the first embodiment of the present invention, the UE signals the required TB size to the Node B, and the Node B transmits a new TB size corresponding to the required TB size to the UE. Generally, the TB size is transmitted over a downlink control channel, called an L1/L2 control channel, and the capacity of the control channel is limited. In addition, because a format of the L1/L2 control channel is fixed, the TB size is signaled together with unnecessary information, for example, resource information or Hybrid Automatic Retransmission reQuest (HARQ) operation-related information. In sum, every time a VoIP packet uncontainable with the TB size occurs, the Node B signals the new TB size over the L1/L2 control channel, causing an inefficiency problem.

[84] In a second embodiment of the present invention, if a MAC PDU containing a required TB size is successfully received, the UE configures and transmits a MAC PDU, considering that the required TB size is the new TB size for the next N transmissions. After the N transmissions of the MAC PDU are completed, the UE uses the original TB size. Although the N is generally '1', it is subject to change.

[85] FIG. 9 is a signaling flow illustrating the entire operation of a UE and a Node B according to the second embodiment of the present invention. It is assumed herein that N is 1 (N=I).

[86] Referring to FIG. 9, in step 915, when a UE 905 and a Node B 910 perform a call setup process for the VoIP service, the Node B 910 signals persistent transmission resources and a TB size for the VoIP service to the UE 905.

[87] When a VoIP packet occurs at the UE 905, the UE 905 includes in step 920 the VoIP packet in a MAC PDU with the TB size and transmits it over the persistent transmission resources. If an appropriate TB size has been defined in step 915, the frequently occurring VoIP packets are contained in the MAC PDU with the TB size without being fragmented. The UE 905 repeats step 920 while the VoIP packets with a size containable in the MAC PDU with the TB size without being fragmented, occur.

[88] If a VoIP packet uncontainable in the MAC PDU with the TB size without being fragmented, i.e., a VoIP packet larger than the frequently occurring VoIP packets, occurs in step 925, the UE 905 includes, in step 930, size information indicating a required TB size in the MAC PDU, and includes a part fragmented from the VoIP packet in the remaining space except for the size information of the MAC PDU, before transmission. If the MAC PDU containing the size information is successfully transmitted to the Node B 910, the UE 905 configures and transmits, in step 935, a MAC PDU using a new TB size, considering that the required TB size is the new TB size at the next N transmission times. If the required TB size was appropriately calculated, all of the remaining part fragmented from the large VoIP packet and the next VoIP packet are contained in the MAC PDU. After transmitting the MAC PDU with the new TB size, the UE 905 configures and transmits a MAC PDU according to the original TB size in step 940. The new TB size can be used for N transmissions according to a predetermined value of the N indicating an interval where the required TB size is valid.

[89] FIG. 10 illustrates a UE' s operation according to the second embodiment of the present invention.

[90] Referring to FIG. 10, in step 1005, the UE receives persistent transmission resources and a TB size to be used for the VoIP service in the uplink, signaled from a Node B. If the UE arrives at the transmission time for use of the persistent transmission resources in step 1010, the UE proceeds to step 1015 where it determines whether a desired transmission VoIP packet can be contained in the MAC PDU with the TB size without being fragmented. Assuming that the MAC PDU is generated by adding an H-byte overhead to the VoIP packet, if the TB size is greater than the size of the VoIP packet by H bytes or more, the UE proceeds to step 1020, as the VoIP packet can be contained in the MAC PDU without being fragmented. However, if the TB size is not greater than the size of the VoIP packet by H bytes or more, the UE proceeds to step 1025, because the VoIP packet should be fragmented.

[91] In step 1020, the UE includes the VoIP packet in the MAC PDU with the TB size, and then proceeds to step 1023 where it transmits the MAC PDU. Thereafter, the UE returns to step 1010 to wait until the next transmission time where it will use the persistent transmission resources. In step 1025, the UE calculates a required TB size using Equation (1) described above. In step 1030, the UE includes the size information indicating the required TB size in the MAC PDU with the TB size, and includes the first part fragmented from the VoIP packet in the remaining space, and then proceeds to step 1035 where it transmits the MAC PDU.

[92] In step 1040, the UE determines whether the MAC PDU containing the size information has been successfully transmitted to the Node B. The determination can be made by, for example, determining whether an Acknowledgement (ACK) for the MAC PDU has been received. If the MAC PDU containing the size information has been successfully transmitted to the Node B, the UE configures in step 1045 a MAC PDU to be transmitted at the next transmission time, according to the required TB size, and then proceeds to step 1055 where it transmits the MAC PDU. Thereafter, the UE returns to step 1010 to wait until the next VoIP packet occurs.

[93] However, if the MAC PDU containing the size information has not been successfully transmitted to the Node B, the UE proceeds to step 1050 where it configures a MAC PDU to be transmitted at the next transmission time, according to the TB size. In this case, the UE configures the MAC PDU by including therein only the next VoIP packet other than the remaining part of the large VoIP packet. This is because transmission of the remaining part of the large VoIP packet is meaningless owing to the loss of a part of the large VoIP packet.

[94] A description will now be made of an example where as a VoIP packet with a z-byte size occurs at, for example, a y-msec time, the UE fragments the VoIP packet into a z 1 -byte part and a z2-byte part, and then transmits a MAC PDU containing the zl-byte part and the required TB size. If the transmission of the MAC PDU is failed, the UE, in a process of configuring a MAC PDU to be transmitted at the next transmission time, configures and transmits the MAC PDU only with the next VoIP packet occurring at the next transmission time of [y + 20] msec, without including therein the remaining z2-byte part.

[95] In step 1055, the UE transmits the MAC PDU configured in step 1050 or 1045, and then returns to step 1010 to wait until the next VoIP packet occurs.

[96] FIG. 11 illustrates a Node B's operation according to the second embodiment of the present invention.

[97] Referring to FIG. 11, in step 1105, the Node B signals persistent transmission resources and a TB size to be used for the VoIP service in the uplink, to a UE. If a MAC PDU is successfully received over the persistent transmission resources in step 1110, the Node B determines in step 1115 whether the received MAC PDU includes size information indicating a required TB size. If the size information is included, the Node B proceeds to step 1125, and otherwise, the Node B proceeds to step 1120.

[98] In step 1120, the Node B process the next MAC PDU, considering that a size of the

MAC PDU to be received next over the persistent transmission resources is the original TB size set in step 1105. However, in step 1125, the Node B notifies the successful receipt of the MAC PDU to the UE, and processes the next N MAC PDUs, perceiving that the next N MAC PDUs have the required TB size. The MAC PDUs following the N MAC PDUs are processed using the original TB size.

[99] In the second embodiment of the present invention, during transmission of the uplink

VoIP packet, if a VoIP packet corresponding not to the TB size occurs, the UE signals the required TB size to the Node B. The same problem occurs even during transmission/reception of the downlink VoIP packet, and there is a need to solve this problem.

[100] In a third embodiment of the present invention, a Node B piggyback- transmits a next TB size on a MAC PDU, and upon receipt of the MAC PDU containing the next TB size, a UE configures a MAC PDU to be transmitted at the next transmission time, using the next TB size piggybacked on the MAC PDU, even though it does not receive a new TB size signaled over the L1/L2 control channel.

[101] FIG. 12 is a signaling flow illustrating the entire operation of a UE and a Node B according to the third embodiment of the present invention.

[102] Referring to FIG. 12, in step 1215, when a UE 1205 and a Node B 1210 perform a call setup process for the VoIP service, the Node B 1210 signals persistent transmission resources and a TB size for the VoIP service to the UE 1205.

[103] When a VoIP packet occurs at the Node B 1210, the Node B 1210 includes, in step 1220, the VoIP packet in a MAC PDU with the TB size and transmits it over the persistent transmission resources. Then the UE 1205 processes the MAC PDU, considering that the MAC PDU received over the persistent transmission resources has the TB size. If an appropriate TB size has been defined in step 1215, the frequently occurring VoIP packets are contained in the MAC PDU with the TB size without being fragmented, during their transmission. The UE 1205 and the Node B 1210 repeat step 1220 while the VoIP packets with a size containable in the MAC PDU with the TB size without being fragmented, are occur.

[104] If a VoIP packet uncontainable in the MAC PDU with the TB size without being fragmented, i.e., a VoIP packet larger than the frequently occurring VoIP packets, occurs in step 1225, the Node B 1210 includes, in step 1230, size information indicating a next TB size in a MAC PDU, includes a part fragmented from the VoIP packet in the remaining space except for the size information of the MAC PDU, and then transmits the MAC PDU to the UE 1205. The next TB size is calculated in the same manner as that of the required TB size, for example, calculated according to Equation (1) described above.

[105] If the MAC PDU containing the size information is successfully transmitted to the UE 1205, the Node B 1210 configures and transmits a MAC PDU in step 1235, considering the next TB size at the next transmission time. Similarly, if the next TB size is contained in the MAC PDU received from the Node B 1210, the UE 1205 processes the MAC PDU, considering that the MAC PDU received next has the next TB size. In this case, the next TB size can be applied to the next N MAC PDUs, where N is a positive integer. The UE 1205 processes the MAC PDUs received thereafter, considering that they have the original TB size. If the next TB size has been appropriately calculated, the remaining part fragmented from the large VoIP packet and the next VoIP packet are all contained in the MAC PDU transmitted in step 1235.

[106] The Node B 1210, after transmitting the MAC PDU with the next TB size, configures and transmits a MAC PDU according to the original TB size in step 1240.

[107] FIG. 13 illustrates a UE's operation according to the third embodiment of the present invention.

[108] Referring to FIG. 13, in step 1305, the UE receives persistent transmission resources and a TB size to be used for the VoIP service in the downlink, signaled from a Node B. If a MAC PDU is successfully received over the persistent transmission resources in step 1310, the UE determines in step 1315 whether size information indicating a next TB size is included in the received MAC PDU. If the size information is included, the UE proceeds to step 1325, and otherwise, the UE proceeds to step 1320.

[109] In step 1320, the UE processes a MAC PDU received next, considering that a size of the MAC PDU to be received next over the persistent transmission resources is the TB size set in step 1305. However, in step 1325, the UE processes the MAC PDU received next, considering that the size of the MAC PDU to be received next over the persistent transmission resources is the next TB size.

[110] FIG. 14 illustrates a Node B's operation according to the third embodiment of the present invention.

[I l l] Referring to FIG. 14, in step 1405, the Node B signals persistent transmission resources and a TB size to be used for the VoIP service in the downlink, to a UE. If the Node B arrives at the transmission time for use of the persistent transmission resources in step 1410, the Node B determines in step 1415 whether a desired transmission VoIP packet can be contained in a MAC PDU with the TB size without being fragmented. Assuming that the MAC PDU is generated by adding an H-byte overhead to the VoIP packet, if the TB size is greater than the size of the VoIP packet by H bytes or more, the Node B proceeds to step 1420, as the VoIP packet can be contained in the MAC PDU without being fragmented. However, if the TB size is not greater than the size of the VoIP packet by H bytes or more, the UE proceeds to step 1425, because the VoIP packet should be fragmented.

[112] In step 1420, the Node B includes the VoIP packet in the MAC PDU with the TB size, and then proceeds to step 1423 where it transmits the MAC PDU. Thereafter, the Node B returns to step 1410 to wait until the next transmission time. In step 1425, the Node B calculates a next TB size using Equation (1) described above. In step 1430, the Node B includes size information indicating the next TB size in the MAC PDU with the TB size, and includes the first part fragmented from the VoIP packet in the remaining space, and then proceeds to step 1435 where it transmits the MAC PDU.

[113] In step 1440, the Node B determines whether the MAC PDU containing the size information has been successfully transmitted to the UE. The determination can be made by, for example, determining whether an ACK for the MAC PDU has been received. If the MAC PDU containing the size information has been successfully transmitted to the UE, the Node B proceeds to step 1445 where it configures a MAC PDU to be transmitted at the next transmission time, according to the next TB size. Thereafter, in step 1455, the Node B transmits the MAC PDU, and then returns to step 1410 to wait until the next transmission time.

[114] However, if the MAC PDU containing the size information has not been successfully transmitted, the Node B proceeds to step 1450 where it configures the MAC PDU to be transmitted at the next transmission time, according to the original TB size. In this case, the Node B configures the MAC PDU by including therein only the next VoIP packet other than the remaining part fragmented from the large VoIP packet. This is because transmission of the remaining part of the large VoIP packet is meaningless owing to the loss of a part of the large VoIP packet.

[115] Thereafter, in step 1455, the Node B transmits the MAC PDU configured in step 1450 or 1445, and then returns to step 1410 to wait until the next transmission time.

[116] In a fourth embodiment of the present invention, when a VoIP packet with a size larger than a predetermined size occurs causing a high possibility that its succeeding VoIP packets will continuously undergo fragmented transmission, a UE transmits a buffer status report message to a Node B to request temporary allocation of new transmission resources.

[117] The buffer status report message, a kind of a control message transmitted to the Node B by the UE, contains buffer status information, such as an amount of data stored in the UE and priority of the data. The buffer status report message generally includes therein a buffer status for all logical channels having transmission data. The logical channel is made for every service on a one-to-one basis, and is composed of devices in charge of storing data generated for each service, framing the data, and performing an Automatic Retransmission reQuest (ARQ) operation thereon.

[118] There are several possible generation conditions of the buffer status report message. For example, it can be provided that the buffer status report message is periodically generated, or the buffer status report message is when high-priority data is newly generated.

[119] The fourth embodiment of the present invention adds the following Condition 1 to the existing generation conditions.

[120] Buffer Status Report Generation Condition 1 (Condition 1 for short)

[121] In this condition, a packet generated in a particular logical channel is transmitted after undergoing fragmentation. In other words, after an upper layer packet is fragmented, a part thereof is transmitted and the other part is left in a logical channel buffer.

[122] Once the VoIP packet undergoes fragmented transmission in this way, its succeeding packets may also continuously undergo fragmented transmission undesirably. To solve this problem, the UE should be temporarily allocated additional transmission resources. To send a request for the additional transmission resources to the Node B, the UE configures a buffer status report message and transmits it to the Node B, when Condition 1 is satisfied, i.e., when a packet generated in a particular logical channel connected to the VoIP service is transmitted after undergoing fragmentation. While the buffer status report message generally includes buffer status for all logical channels where data is stored, the buffer status report message generated by Condition 1 may include buffer status of only the particular logical channel, or buffer status of only the logical channels being higher in priority than the particular logical channel, including the particular logical channel.

[123] FIG. 15 illustrates a UE's operation according to the fourth embodiment of the present invention.

[124] Referring to FIG. 15, in step 1505, the UE perceives a logical channel to which it will apply Buffer Status Report Generation Condition 1. In step 1510, the UE monitors buffer status of the logical channel. If it is determined in step 1515 that a packet stored in a buffer of the logical channel is transmitted after undergoing fragmentation, i.e., if the packet stored in the buffer of the logical channel cannot be transmitted at once and a part thereof is left in the buffer, the UE proceeds to step 1520 where it generates a buffer status report message. Herein, the packet stored in the buffer of the logical channel can be, for example, an RLC Service Data Unit (SDU).

[125] In this case, the UE can determine whether to generate the buffer status report message, taking further into account a size of the remaining non-transmitted fragmented part. For example, if the size of the remaining part is greater than or equal to a predetermined threshold, the UE determines to generate the buffer status report message, and if the size of the remaining packet is less than the threshold, the UE determines not to generate the buffer status report message.

[126] In step 1520, the UE, in a process of configuring the buffer status report message, includes therein the buffer status of only the logical channel, or includes the buffer status of logical channel(s) being higher in priority than the logical channel in addition to the buffer status of the logical channel. For example, the term 'buffer status' refers to information indicating an amount of data stored in each buffer, or to information indicating an amount of data stored in each buffer and information indicating a size of the remaining non-transmitted fragmented part. After generating and transmitting the buffer status report message, the UE returns to step 1510 and continues the buffer status monitoring for the logical channel, unless the service of the logical channel is closed.

[127] A description will now be made of block diagrams of the UE and the Node B applicable to the embodiments of the present invention.

[128] FIG. 16 is a block diagram illustrating a UE apparatus according to a preferred embodiment of the present invention. As illustrated, the UE apparatus includes a multiplexing/demultiplexing unit 1605, an HARQ processor 1615, a transceiver 1630, a controller 1625, and a control channel processor 1620.

[129] Referring to FIG. 16, the transceiver 1630, under the control of the controller 1625, receives data from a wireless channel, and/or transmits data over a wireless channel. More specifically, in transmitting data over the wireless channel, the transceiver 1630 transmits a TB configured depending on a TB size designated by the controller 1625, over the transmission resources designated by the controller 1625. In receiving data from the wireless channel, the transceiver 1630 receives a TB over the transmission resources designated by the controller 1625, using the TB size designated by the controller 1625.

[130] The controller 1625 determines transmission resources and a TB size to be used for uplink transmission, according to signaling from a Node B by way of the control channel processor 1620, and controls a transmission operation of the transceiver 1630 according thereto. For the service to which persistent transmission resources are allocated, the controller 1625 controls the transceiver 1630 so as to transmit a TB at a predetermined time using the persistent transmission resources and the TB size. The controller 1625 compares a size of the packet stored in a transmission buffer (not shown) in the multiplexing/demultiplexing unit 1605 with the TB size to determine whether to fragment the packet. When the controller 1625 determines to fragment the packet, it calculates a required TB size, and transfers size information indicating the required TB size to the multiplexing/demultiplexing unit 1605. The multiplexing/de- multiplexing unit 1605 configures a TB containing the required TB size, and delivers it to the HARQ processor 1615.

[131] In addition, the controller 1625 determines transmission resources and a TB size to be used for downlink reception, according to signaling from the Node B, and controls a reception operation of the transceiver 1630 according thereto. For the service to which persistent transmission resources are allocated, the controller 1625 controls the transceiver 1630 so as to receive a TB at a predetermined time using the designated persistent transmission resources and TB size. If the TB received at the transceiver 1630 contains size information indicating a next TB size, the controller 1625 controls the transceiver 1630 so as to apply the next TB size to the TB received at the next reception time using the persistent transmission resources.

[132] Alternatively, the controller 1625 monitors whether a packet undergoes fragmented transmission in a logical channel to which Buffer Status Report Generation Condition 1 is to be applied, and if there is a packet undergoing fragmented transmission, the controller 1625 configures a predetermined buffer status report message and delivers it to the multiplexing/demultiplexing unit 1605.

[133] The multiplexing/demultiplexing unit 1605 multiplexes the packets generated in the upper layer into one TB, and delivers it to the HARQ processor 1615. Further, the multiplexing/demultiplexing unit 1605 demultiplexes the TB delivered from the HARQ processor 1615, and transfers the results to an appropriate upper layer. The HARQ processor 1615 transfers the TB from the multiplexing/demultiplexing unit 1605 after performing an HARQ operation thereon, or receives the TB from the transceiver 1630 by means of an HARQ operation.

[134] FIG. 17 is a block diagram illustrating a Node B apparatus according to a preferred embodiment of the present invention. As illustrated, the Node B apparatus includes a multiplexing/demultiplexing unit 1705, an HARQ processor 1715, a transceiver 1730, a controller/scheduler 1725, and a control channel processor 1720.

[135] Referring to FIG. 17, the transceiver 1730, under the control of the controller/ scheduler 1725 (hereinafter, controller for short), receives data from a wireless channel, and/or transmits data over a wireless channel. More specifically, in transmitting data over the wireless channel, the transceiver 1730 transmits a TB configured depending on a TB size designated by the controller 1725, over the transmission resources designated by the controller 1725. In receiving data from the wireless channel, the transceiver 1730 receives a TB over the transmission resources designated by the controller 1725, using the TB size designated by the controller 1725.

[136] The controller 1725 serves to allocate transmission resources to the UE taking into account the channel condition and the amount of transmission data of each UE. In allocating the persistent transmission resources, the controller 1725 determines persistent transmission resources and TB sizes for the uplink and downlink, and notifies them to the UE.

[137] According to the first embodiment, if a MAC PDU received by the transceiver 1730 contains size information indicating a required TB size, the controller 1725 signals the new TB size to the UE by means of the control channel processor 1720, and if necessary, allocates separate transmission resources. According to the second embodiment, if a MAC PDU received by the transceiver 1730 contains size information indicating a required TB size, the controller 1725 controls the transceiver 1730 so as to process N packets received over the uplink persistent transmission resources using the required TB size. According to the third embodiment, if the desired transmission packet cannot be fully contained in a TB with a preset TB size, the controller 1725 calculates a next TB size, and delivers it to the multiplexing/demultiplexing unit 1705.

[138] The multiplexing/demultiplexing unit 1705 includes size information indicating the next TB size in a MAC PDU, and transmits the MAC PDU to the UE. In addition, the multiplexing/demultiplexing unit 1705 multiplexes the packets generated in the upper layer into one TB and delivers it to the HARQ processor 1715. Further, the multiplexing/demultiplexing unit 1705 demultiplexes the TB transferred by the HARQ processor 1715, and transfers it to an appropriate upper layer. The HARQ processor 1715 transmits the TB from the multiplexing/demultiplexing unit 1705 after performing an HARQ operation, or receives the TB from the transceiver 1730 by means of the HARQ operation.

[139] While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

[1] A method for transmitting variable-sized packets in a mobile communication system, the method comprising: when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB with the TB size to the Node B; receiving a new TB size determined according to the size information from the Node B; and transmitting at least one following packet to the Node B according to the new TB size.

[2] The method of claim 1, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[3] The method of claim 2, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[4] A User Equipment (UE) apparatus for transmitting variable-sized packets in a mobile communication system, the apparatus comprising: a controller for, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transceiver for transmitting the TB to the Node B, and receiving a new TB size determined according to the size information from the Node B to provide the new TB size to the controller.

[5] The UE apparatus of claim 4, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[6] The UE apparatus of claim 5, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[7] A method for receiving variable- sized packets in a mobile communication system, the method comprising: signaling a Transport Block (TB) size to a User Equipment (UE); upon receipt of a TB with the TB size from the UE, determining whether size information indicating a required TB size of the UE is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and transmitting a new TB size determined according to the size information to the UE; and receiving at least one following packet including a remaining part of the packet from the UE according to the new TB size.

[8] The method of claim 7, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[9] The method of claim 8, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[10] A Node B apparatus for receiving variable- sized packets in a mobile communication system, the apparatus comprising: a transceiver for receiving, from a User Equipment (UE), a Transport Block (TB) with a TB size signaled to the UE; and a controller for, when size information indicating a required TB size of the UE is included in the TB, extracting a fragmented part of a packet from the TB, transmitting a new TB size determined according to the size information to the UE by means of the transceiver, and controlling the transceiver to receive at least one following packet including a remaining part of the packet from the UE according to the new TB size.

[11] The Node B apparatus of claim 10, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[12] The Node B apparatus of claim 11, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[13] A method for transmitting variable-sized packets in a mobile communication system, the method comprising: when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the

TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB to the Node B; and after a TB including the size information is successfully transmitted to the Node

B, transmitting at least one following packet to the Node B according to the required TB size for at least one predetermined transmission time.

[14] The method of claim 13, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[15] The method of claim 14, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[16] A User Equipment (UE) apparatus for transmitting variable-sized packets in a mobile communication system, the apparatus comprising: a controller for, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled from a Node B without being fragmented, including, in the TB with the TB size, size information indicating a required TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transmission unit for transmitting one of the TBs to the Node B, and after a TB including the size information is successfully transmitted to the Node B, transmitting a following TB including a following packet to the Node B according to the required TB size for at least one predetermined transmission time.

[17] The UE apparatus of claim 16, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[18] The UE apparatus of claim 17, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[19] A method for receiving variable- sized packets in a mobile communication system, the method comprising: signaling a Transport Block (TB) size to a User Equipment (UE); upon receipt of a TB with the TB size from the UE, determining whether size information indicating a required TB size of the UE is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and notifying to the UE the successful receipt of the TB including the size information; and receiving at least one following packet from the UE according to the required TB size.

[20] The method of claim 19, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[21] The method of claim 20, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[22] A Node B apparatus for receiving variable- sized packets in a mobile communication system, the apparatus comprising: a reception unit for receiving, from a User Equipment (UE), a Transport Block (TB) with a TB size signaled to the UE; and a controller for, when size information indicating a required TB size of the UE is included in the TB, extracting a fragmented part of a packet from the TB, notifying to the UE the successful receipt of the TB including the size information, and controlling the reception unit to receive at least one following packet from the UE according to the required TB size.

[23] The Node B apparatus of claim 22, wherein the required TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[24] The Node B apparatus of claim 23, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[25] A method for transmitting variable-sized packets in a mobile communication system, the method comprising: when a packet can be contained in a Transport Block (TB) with a TB size signaled to a User Equipment (UE) without being fragmented, including, in the TB with the TB size, size information indicating a next TB size calculated depending on a size of a next packet, along with a fragmented part of the packet, and transmitting the TB to the UE; and after the TB including the size information is successfully transmitted to the UE, transmitting at least one following packet to the UE according to the next TB size for at least one predetermined transmission time.

[26] The method of claim 25, wherein the next TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[27] The method of claim 26, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[28] A Node B apparatus for transmitting variable-sized packets in a mobile communication system, the apparatus comprising: a controller for, when a packet cannot be contained in a Transport Block (TB) with a TB size signaled to a User Equipment (UE) without being fragmented, including, in the TB with the TB size, size information indicating a next TB size calculated depending on a size of a next packet, along with a fragmented part of the packet; and a transceiver for transmitting one of the TBs to the UE, and after the TB including the size information is successfully transmitted to the UE, transmitting at least one following TB including at least one following packet to the UE according to the next TB size for at least one predetermined transmission time.

[29] The Node B apparatus of claim 28, wherein the next TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[30] The Node B apparatus of claim 29, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[31] A method for receiving variable- sized packets in a mobile communication system, the method comprising: upon receipt of a Transport Block (TB) with a TB size signaled by a Node B from the Node B, determining whether size information indicating a next TB size of the Node B is included in the TB; when the size information is included, extracting a fragmented part of a packet from the TB, and notifying to the Node B the successfully receipt of the TB including the size information; and receiving at least one following packet from the Node B according to the next TB size.

[32] The method of claim 31 , wherein the next TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[33] The method of claim 32, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[34] A User Equipment (UE) apparatus for receiving variable- sized packets in a mobile communication system, the apparatus comprising: a reception unit for receiving a Transport Block (TB) with a TB size signaled by a Node B from the Node B; and a controller for, when size information indicating a next TB size of the Node B is included in the TB, extracting a fragmented part of a packet from the TB, notifying to the Node B the successfully receipt of the TB including the size information, and controlling the reception unit to receive at least one following packet from the Node B according to the next TB size.

[35] The UE apparatus of claim 34, wherein the next TB size is a sum of a size of the next packet, a size h of a header included in each TB, a size s of the size information, and a size excess k of the packet, and the size excess is a difference between an expected packet size containable in the TB size and a size of the packet.

[36] The UE apparatus of claim 35, wherein the size of the next packet is determined as a size of a buffered packet to be transmitted at a next transmission time, or the expected packet size.

[37] A method for transmitting variable-sized packets in a mobile communication system, the method comprising: determining whether a packet generated in a logical channel in service is transmitted after being fragmented; and when the packet generated in the logical channel is transmitted after being fragmented, configuring a buffer status report message including a buffer status of the logical channel and transmitting the buffer status report message to a Node B, to request additional transmission resources for a remaining fragmented part of the packet of the logical channel.

[38] The method of claim 37, wherein the determining comprises: determining to generate the buffer status report message, when there is a remaining non-transmitted fragmented part in the packet stored in a buffer of the logical channel and a size of the remaining part is greater than or equal to a predetermined threshold.

[39] The method of claim 37, wherein the buffer status report message further comprises a buffer status of at least one logical channel which is higher in priority than the logical channel.

[40] A User Equipment (UE) apparatus for transmitting variable-sized packets in a mobile communication system, the apparatus comprising: a controller for, when a packet generated in a logical channel in service is transmitted after being fragmented, configuring a buffer status report message including a buffer status of the logical channel to request additional transmission resources for a remaining fragmented part of the packet of the logical channel; and a transmission unit for transmitting the buffer status report message to a Node B.

[41] The UE apparatus of claim 40, wherein the controller determines to generate the buffer status report message, when there is a remaining non-transmitted fragmented part in the packet stored in a buffer of the logical channel and a size of the remaining part is greater than or equal to a predetermined threshold.

[42] The UE apparatus of claim 40, wherein the buffer status report message further comprises a buffer status of at least one logical channel which is higher in priority than the logical channel.