RU2404524C2 - Data transfer in mobile communication system - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: method for repeated transfer of data unit in mobile communication system comprises stage, where: it is determined whether the first data unit fits into the volume of data unit specified by the lower level, if the first data unit has not been successfully transferred to receiving side; the first data unit is segmented to generate the second data unit, if the first data unit does not fit into the volume of data unit specified by the lower level. At the same time the second data unit fits into volume of data unit specified by the lower level; and the second data unit is repeatedly sent to receiving side.

EFFECT: improved process of repeated data transfer.

18 cl, 9 dwg, 4 tbl

Description

FIELD OF THE INVENTION

The present invention relates to a mobile communication system, and more particularly to data transmission in a mobile communication system.

State of the art

Figure 1 shows a structural diagram illustrating a mobile communication system for long-term development (LTE, DR). The LTE system is a development of the version of the conventional universal mobile communication system (UMTS, USMS) and is standardized in accordance with the 3rd generation partnership project cooperation agreement (3GPP, PTPP).

An LTE network can generally be divided into an advanced UMTS wide area radio access network (E-UTRAN, GSRUU) and a core network (CN, BS). An E-UTRAN includes at least one eNode-B used as a base station. The E-UTRAN also includes an access gateway (AG), located at the end of the network so that it is connected to an external network.

The AG can be divided into a user traffic processing module and a control traffic processing module. In this case, the first AG designed to process the new user traffic data may communicate with the second AG to process the control traffic data via the new interface. A single eNode-B may include at least one cell. A first interface for transmitting user traffic data or a second interface for transmitting control traffic data may be located between multiple eNode-Bs. CN includes an AG and a plurality of nodes for registering users of user equipment (UEs, OPs). If required, another interface that distinguishes between E-UTRAN and CN can also be used on an LTE network.

Two important elements of an LTE network are eNode-B and UE. The radio resources of one cell include radio resources of the uplink channel and radio resources of the downlink channel. The eNode-B node allocates radio resources and manages the radio resources of the upstream and downstream channels. In more detail, the eNode-B determines which of the many UEs will use certain radio resources at a particular point in time. After the determination is made, the eNode-B informs the specific UE of its decision, so that the eNode-B controls the UE to receive data transmitted in the downlink. For example, an eNode-B may allocate radio resources in the range from 100 MHz to 101 MHz to a specific UE (e.g., UE No. 1) after a predetermined time of 3.2 seconds has passed. Accordingly, the eNode-B may transmit data on the downlink data channel to UE No. 1 during a predetermined time of 0.2 seconds after the predetermined time of 3.2 seconds has passed.

Thus, the eNode-B determines which of the many UEs will transmit data on the uplink data channel and the amount of radio resources that the UE can use at a particular point in time. In addition, the eNode-B determines the length of time that the UE receives for transmitting data on the uplink data channel.

Compared to an eNode-B or a prior art base station, the above-described eNode-B can efficiently and dynamically control radio resources. In the prior art, a single UE is controlled in such a way that it constantly uses one radio resource during a call connection. However, given the existence of many recent services based on Internet protocol (IP, IP) packets, prior art solutions have become ineffective. For example, most packet data services have several intervals during which they do not transmit data or generate packets during a call connection. Thus, if radio resources are constantly allocated to only one UE, as in the prior art, the allocation scheme is considered inefficient. To solve this and other problems, an E-UTRAN system was developed to allocate UE radio resources only when it is necessary to use a UE, for example, when it is necessary to transfer service data to the UE.

The uplink and downlink data channels for transmitting data between the network and the UE will be described in detail below. There are downstream channels for transmitting data from the network to the UE, such as a broadcast channel (BCH, UWB) for transmitting system information, and a downstream shared channel (SCH, SIC), and a downstream shared control channel (SCCH, SEC) designed to transmit user traffic data or control messages. Traffic data or control messages of a multicast service or data of a broadcast service transmitted in a downlink can be transmitted through a downlink shared channel (SCH, SIC) or additionally through a multicast channel (MCH, MAC). In addition, there are also upstream channels for transmitting data from the UE to the network, such as a random access channel (RACH), and an upstream shared channel (SCH, VSIC), and an upstream shared control channel (SCCH, ASIC) designed to transmit user traffic data or control messages.

FIG. 2 and FIG. 3 are conceptual diagrams illustrating a structure of a radio interface protocol between a UE and a UMTS wide area radio access network (UTRAN), which is based on the 3GPP radio access network standard.

The horizontal interface protocol includes the physical layer, link layer, and network layer. The vertical air interface protocol includes a user plane for transmitting data or information, and a control plane for transmitting control signals (also called “signal transmission data”). The protocol layers shown can be divided into a first layer (L1), a second layer (L2) and a third layer (L3) based on the three lower layers of a well-known interconnection scheme, such as an open system reference model (OSI, BOC).

The physical layer, acting as the first level (L1), represents a service for transmitting information on a physical channel. The radio resource control layer (RRC, URL) located at the third level (L3) controls radio resources in the interaction between the UE and the network. To this end, the RRC layer performs RRC messaging between the UE and the network. The RRC layer can be distributed across multiple network nodes (i.e., eNode-B and AG, etc.) and can also be located in eNode-B or in AG.

Below, with reference to FIG. 2, a radio protocol control plane will be described. The radio protocol control plane includes a physical layer, a medium access control (MAC, MAC) layer, a radio channel control layer (RLC, URC), and a radio resource control layer (RRC, URR).

The physical layer, which plays the role of the first level (L1), transmits a service for transmitting information to the upper level through a physical channel. The physical layer is connected to a medium access control (MAC) layer (L2 level) through a transport channel. The MAC layer is associated with the physical layer in such a way that data is transferred between the MAC layer and the physical layer through a transport channel. Data can be transferred between different physical layers. In particular, data is transferred between the first physical end-of-transmission layer and the second physical end-of-reception layer.

The MAC layer of the second level (L2) transmits various services to the RLC (radio channel control) layer (L2 level) via a logical channel. The RLC layer of the second level (L2) supports the transmission of reliable data. Various functions of the RLC layer can also be implemented using the block of functions of the MAC layer. In this case, the RLC level is not required.

The RRC (Radio Resource Control) level located at the top of the third level (L3) is defined only by the control plane. The RRC layer controls the logical channels, transport channels, and physical channels with respect to configuration operations, configuration changes, and radio carrier releases (RB, PH). Here, RB denotes a service received from a second layer (L2) for implementing data transmission between a UE and an E-UTRAN.

The plane of the user’s radio protocol will be described below with reference to FIG. 3. The user radio protocol plane includes a physical layer, a MAC layer, an RLC layer, and a packet data convergence protocol (PDCP) layer.

The physical layer of the first level (L1) and the MAC and RLC levels of the second level (L2) are equivalent to those shown in FIG. For efficient transmission of IP packets (eg, IPv4 or IPv6) during a narrow band radio communication period, a second layer PDCP layer (L2) performs header compression to reduce the size of a relatively large IP packet header containing unnecessary control information.

Description of the RLC level will be presented in detail below. The main functions of the RLC layer are to guarantee the quality of service (QoS, QoS) of each RB and transmit data related to QoS. The RB service denotes a specific service provided for the upper layer by the second layer of the radio protocol so that all parts of the second layer affect QoS. In particular, it should be noted that the second level is significantly affected by the RLC level. The RLC layer assigns an independent RLC entity to each RB in order to guarantee a unique RB QoS. In this case, the RLC entity configures the RLC protocol data unit (PDU, TIR) in accordance with the amount of radio resources defined by the lower layer (i.e., the MAC layer).

Therefore, when transmitting the RLC PDU to the MAC layer, the RLC object located in the eNode-B node configures data having a predetermined size defined by the MAC object and transmits the RLC PDU to the MAC object. The RLC entity located in the UE also configures the RLC PDUs according to the amount of radio resources defined by the lower layer (i.e., the MAC layer). Therefore, when transmitting an RLC PDU to the MAC layer, an RLC object located in the UE configures data having a predetermined size defined by the MAC object, and transmits the RLC PDU to the MAC object.

Disclosure of invention

The present invention is directed to data transmission in a mobile communication system.

Additional features and advantages of the invention will be presented in the following description and will be partially understood from the description or may be understood as a result of the practical application of the invention. The objectives and other advantages of the invention will be realized and achieved using the structure, in particular, presented in the written description and claims, as well as in the attached drawings.

To achieve these and other advantages, and in accordance with the purpose of the present invention, as embodied and described in general terms, the present invention is embodied in a method for transmitting data in a mobile communication system, the method comprising the steps of: transmitting the first data to the receiving side, confirmation information is received to indicate whether the first data was successfully transmitted to the receiving side, if the first data was not successfully transmitted to the receiving side, it is determined whether there is enough available radio resources for retransmitting the first data to the receiving side, retransmit the first data to the receiving side if the amount of available radio resources is sufficient to retransmit the first data, change the configuration of the first data to at least one second data, if the amount of available radio resources is insufficient, for retransmitting the first data, in which at least one second data can be transmitted to the receiving side using the amount of available radio resources, and transmitting at least one second data on the receiving side.

Preferably, acknowledgment information is received from the receiving side. Preferably, acknowledgment information is received from a lower layer of the transmitting side.

In one aspect of the present invention, the first data is a radio channel control layer protocol data module (RLC PDU, MCA TIR) comprising at least one of: a sequence number field (SN, PN), a control / data / subframe field (C / D / S, Y / D / P), full / partial field (C / P, P / H), next field (F, C) and length indicator field (LI, ID). Preferably, the control / data / subframe (C / D / S) field indicates whether the RLC PDUs are first data or second data. Preferably, the C / P field indicates how the RLC PDU is aligned with the upper layer service data unit (SDU).

In another aspect of the present invention, the second data is a sub-protocol radio channel control layer (RLC subPDU) data unit comprising at least one of: a serial number (SN) field, a control / data / subframe (C / D / S) field, subframe sequence number field (sSN, PNS), rest field (RM), full / partial field (C / P), next field (F) and length indicator field (LI). Preferably, the sSN field indicates the serial number of one of the at least one second data within the plurality of transmitted second data related to the first data. Preferably, the RM field indicates whether subsequent second data exists after one of the at least one second data.

In an additional embodiment of the present invention, the amount of available radio resources contains the maximum amount of data scheduled for transmission to the receiving side.

In yet another aspect of the present invention, the maximum amount of available radio resources is indicated by scheduling information received from the network. Preferably, the scheduling information indicates time points and frequency of available radio resources.

In accordance with another embodiment of the present invention, a device for transmitting data to a mobile communication system comprises means for transmitting first data to a receiving side, means for receiving confirmation information to indicate whether the first data has been successfully transmitted to the receiving side if the first data has not been successfully transmitted to receiving side, means for determining whether there is enough available radio resources to retransmit the first data to the receiving side, means for retransmitting the first data on the receiving side, if the amount of available radio resources is sufficient for the first data, means for reconfiguring the first data into at least one second data, if the amount of available radio resources is insufficient, for retransmission of the first data in which at least one second data can be transmitted to the receiving side, using the amount of available radio resources, and means for transmitting at least one second data to the receiving side.

Preferably, confirmation information is received from the receiving side. Preferably, acknowledgment information is received from a lower layer of the transmitting side.

In one aspect of the present invention, the first data is a radio channel control layer (RLC PDU) protocol data unit comprising at least one of: a serial number (SN) field, a control / data / subframe (C / D / S) field, full / partial field (C / P), next field (F) and length indicator field (LI).

In another aspect of the present invention, the second data is a sub-protocol radio channel control layer data unit (RLC subPDU) comprising at least one of: a serial number (SN) field, a control / data / subframe (C / D / S) field, subframe sequence number field (sSN), rest field (RM), full / partial field (C / P), next field (F) and length indicator field (LI).

In an additional aspect of the present invention, the amount of available radio resources contains the maximum amount of data scheduled for transmission to the receiving side.

In yet another aspect of the present invention, the maximum amount of available radio resources is indicated by scheduling information received from the network. Preferably, the scheduling information indicates time points and frequency of available radio resources.

It should be understood that both the previous general description and the following detailed description of the present invention are exemplary and explanatory and are intended to further clarify the invention, as claimed.

Brief Description of the Drawings

The accompanying drawings, which are included for a better understanding of the invention and are incorporated by reference herein, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. The properties, elements, and aspects of the referenced invention, using the same reference numerals in different figures, represent the same, equivalent, or similar properties, elements, or aspects in accordance with one or more embodiments.

1 is a block diagram illustrating a long term evolution (LTE) mobile communication system.

2 is a diagram illustrating a control plane of a radio interface protocol structure between a UE and a UMTS wide area radio access network (UTRAN) based on a 3GPP radio access network standard.

3 is a diagram illustrating a user plane and a structure of a radio interface protocol between a UE and a UMTS wide area radio access network (UTRAN) based on the 3GPP radio access network standard.

4 is a diagram illustrating a method of constructing a MAC PDU in an RLC SDU in accordance with one embodiment of the present invention.

5 is a block diagram illustrating a MAC PDU format in accordance with one embodiment of the present invention.

6 is a flowchart illustrating a data transmission method of a mobile communication system in accordance with one embodiment of the present invention.

7 is a diagram illustrating a data transmission method of a mobile communication system in accordance with one embodiment of the present invention.

8 is a diagram illustrating a signal transmission method of a mobile communication system in accordance with another embodiment of the present invention.

9 is a diagram illustrating a signal transmission method of a mobile communication system in accordance with yet another embodiment of the present invention.

The implementation of the invention

The present invention relates to data transmission in a mobile communication system.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the attached drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Below will be described a method of transmitting data in a mobile communication system in accordance with the present invention.

Before describing the present invention, it should be noted that the following preferred embodiments of the present invention allow the RLC layer to reconfigure information received from the upper layer in the above hierarchical structure shown in the description of the prior art and transmit the reconfigured information to the MAC layer. However, it will be apparent to those skilled in the art that the scope of the present invention is not limited only to the above case of transmitting an RLC layer, and it can also be applied to other examples. The first information transmitted from the upper layer and received by the RLC layer is called the RLC service data unit (SDU). The second information that contains the RLC SDU, the configuration of which is changed by the RLC layer and transmitted to the MAC layer, is called the RLC PDU. The third information that contains the RLC PDU, the configuration of which is changed by the MAC layer, is called the MAC PDU.

The RLC layer provides two RLC modes, i.e., an unconfirmed mode (UM (HP) or UM mode) and a confirmed mode (AM (PR) or AM mode). UM and AM modes support different QoS, so they use different operations. The detailed functions of the UM and AM modes also differ from each other. Accordingly, the function of the RLC layer in accordance with its operating modes will be described.

For convenience and a better understanding of the present invention, RLC in UM mode is called UM RLC, while RLC in AM mode is referred to as AM RLC. The UM RLC attaches a PDU header including a sequence number (SN) to each generated PDU and transmits the resulting PDU provided with a PDU header so that the receiving party can recognize which of the plurality of PDUs was lost during transmission. Accordingly, the UM RLC preferably performs broadcast / multicast data transmission or real-time packet data transmission (using, for example, a voice over Internet protocol (VoIP) or streaming data) in a packet service domain (PS, MS) data transfer in the user plane. In the control plane, the UM RLC preferably transmits the UM RRC message among the plurality of RRC messages transmitted to a specific UE or to a specific UE group contained in the cell.

AM RLC attaches a PDU header including an SN to each PDU generated in the same manner as a UM RLC; however, unlike the UM RLC, the AM RLC transmits a command that the receiving side has confirmed the PDU transmitted by the transmitting side. Accordingly, when performing PDU confirmation, the receiving side may request a retransmission of any PDU not received from the transmitting side.

Using the retransmission function, AM RLC can guarantee error-free data transmission. Accordingly, the AM RLC performs a non-real-time data packet transmission, such as transmission using a transmission control protocol / Internet protocol (TCP / IP, PUP / MP) in the PS domain, in the user plane. In the control plane, the AM RLC transmits an RRC message that requires an acknowledgment response (AM RRC message) among the plurality of RRC messages transmitted to the specific UE contained in the cell.

In terms of directions, AM RLC is used for bi-directional data transmission since a feedback signal is received from the receiving side, while UM RLC is used for unidirectional data transmission. Preferably, bi-directional data transmission is used for point-to-point communication (PTP, ITT), so that the AM RLC uses a dedicated logical channel.

Structurally, the UM RLC includes a single RLC entity comprising a single transmission structure or a single receive structure. In contrast, an AM RLC includes a single RLC entity containing a transmission structure and a reception structure. The AM RLC structure is more complex due to the retransmission function. To control the retransmission function, the AM RLC includes a transmit / receive buffer as well as a retransmission buffer and performs various functions. The RLC AM functions include the function of using a transmit / receive window to control the flow of information, a polling function for requesting status information from the receiving side of the RLC node object by the transmitting side, a status report function that enables the receiving side to report the status of its buffer to the transmitting side of the node object -RLC, a PDU status function for transmitting status information and an embedding function for inserting PDU status into PDU data, for improving data transmission efficiency, for example.

In addition, if the AM RLC detects serious errors during its operation, the AM RLC can perform additional functions, such as the PDU reset function to request a configuration change of all operations and parameters from the interacting AM RLC object and the ACK PDU reset function, for example, to respond to reset PDU.

To support the above functions, the AM RLC requests various protocol parameters, state variables, and a timer. The various PDUs used for the above functions, such as the status report function, the status PDU function, and the reset PDU function, as well as the PDUs for controlling the transmission of AM RLC data, are called control PDUs. Other PDUs for transmitting user data are called data PDUs.

Preferably in the AM mode, the automatic repeat request information (ARQ, AZP) is used, and in the UM mode this is not used. Here, the ARQ information denotes transmission / reception acknowledgment information (ACK, ACK). Preferably, the ACK transmit / receive information denotes information related to a data block typically transmitted from a transmitting side to a receiving side, or other information related to a data block with errors that is abnormally transmitted from a transmitting side to a receiving side.

A representative example of the RLC PDU format for use in UM mode is presented in Table 1.

[Table 1] SN C / p F Li F Li ... F RLC SDU1 RLC SDU2 ... RLC SDU N

As shown in Table 1, the serial number (SN) field indicates the data stream of the corresponding RLC PDU or indicates the location information on the logical channel. The full / partial (C / P) field indicates whether the first part of the RLC PDU data is equal to the first part of the corresponding SDU. The C / P field also indicates whether the last part of the RLC PDU data is equal to the final part of any associated SDUs.

For example, if the value of the C / P field is “00”, the starting part of the PDU is equal to the starting part of the SDU, and the ending part of the PDU is equal to the ending part of the SDU. If the value of the C / P field is “01”, the starting part of the PDU is equal to the starting part of the SDU, and the ending part of the PDU is not equal to the ending part of the SDU. If the value of the C / P field is “10”, the starting part of the PDU is not equal to the starting part of the SDU, and the ending part of the PDU is equal to the ending part of the SDU. If the value of the C / P field is “11”, the starting part of the PDU is not equal to the starting part of the SDU, and the ending part of the PDU is not equal to the ending part of the SDU.

The Length Indicator (LI) field indicates the boundary of the RLC SDU. Thus, if a single RLC PDU includes two RLC SDUs, the receiving side can share the RLC SDU using the RLC SDU boundary information. The next field (F) indicates whether the next field is an LI field or data.

When compared with AM mode, the UM mode RLC PDU format should not transmit / receive transmit / receive acknowledgment information. Accordingly, the RLC PDU of the UM mode is simpler than the AM mode, and may have one header format. In addition, if the transmission time point of the corresponding RLC PDU can be distinguished at the lower end in accordance with retransmission information (i.e., redundancy information - version), then the SN field can be deleted.

A representative example of the ARQ RLC PDU format for transmitting common data in AM mode is shown in Table 2.

[Table 2] SN C / D / S C / p F Li F Li ... F RLC SDU 1 RLC SDU 2 ... RLC SDU N PDU Management (optional)

A representative example of an ARQ RLC PDU format for transmitting control information (eg, transmit / receive acknowledgment information) in AM mode is shown in Table 3.

[Table 3] SN C / D / S PDU Management

Preferably, if the ARQ RLC PDU format in Table 2 cannot be transmitted to the destination without any changes in AM mode, the ARQ RLC subPDUs are configured. Accordingly, a representative example of an ARQ RLC PDU is shown in Table 4.

[Table 4] SN C / d / s sSN RM C / p F Li F Li ... F RLC SDU 1 RLC SDU 2 ... RLC SDU N PDU Management
(optional)

As shown in Tables 2, 3 and 4, the SN field, the C / P field, the LI field and the F field correspond to the similar fields shown in Table 1. Therefore, for convenience, a detailed description will not be given here.

The control / data / subframe (C / D / S) field indicates whether the corresponding RLC PDU, ARQ RLC PDU, ARQ RLC control PDU, or ARQ RLC subPDU. The Subframe Sequence Number (sSN) field indicates location information of a corresponding subPDU among a plurality of allocated subPDUs. The rest (RM) field indicates the presence or absence of an associated subPDU after the corresponding subPDU. With this in mind, the ARQ RLC subPDUs presented in Table 4 will be described in detail with reference to the following preferred embodiments of the present invention.

4 is a diagram illustrating a method of constructing a MAC PDU in an RLC SDU in accordance with one embodiment of the present invention. Preferably, the present invention is directed to a method of constructing a data module at the RLC or MAC level.

As shown in FIG. 4, the MAC layer of the UE receives information indicating the amount of available radio resources from the eNode-B. Preferably, the MAC layer receives certain information indicative of the amount of radio resources that can be used during the next transmission time from eNode-B.

From an eNode-B perspective, the eNode-B MAC layer determines whether downlink or uplink radio resources will be used. The eNode-B MAC layer also determines the amount of radio resources that will be allocated to individual UEs during the next transmission period, and informs the MAC level of each UE about the result of this determination. Given the many data modules stored in the UE buffers and the priority of these data modules, each of the UEs determines the amount of data to be transmitted through each logical channel or from each RLC entity. In other words, each RLC entity determines the size of the RLC PDU to be transmitted to the MAC layer.

Accordingly, given the amount of UE downlink data and the priority of each data, the MAC layer located in the eNode-B determines the amount of data to be allocated to individual RLC entities and informs each RLC of the result of this determination. Each RLC then configures the RLC PDUs in accordance with this definition and transfers the RLC PDUs to the MAC layer.

Preferably, the MAC entity is connected to several RLC entities. Each RLC object receives an RLC SDU from the upper layer, generates an RLC SDU, applying a MAC layer command to the received RLC SDU, and transmits the generated RLC SDU to the MAC object. The MAC object combines the RLC PDUs received from the individual RLC objects, configures the combined RLC PDUs in the form of one MAC PDU, and transmits one MAC PDU to the physical layer.

In order to improve communication efficiency in the situation described above, it is preferable that the number of padding bits contained in the MAC PDU or RLC PDU be reduced. Preferably, the predetermined number of bits used to adjust the size is reduced. For this operation, the MAC object receives data from several logical channels (i.e., several RLC objects) and configures the MAC PDU using the received data.

However, in order to send a command to the receiving side for normal recovery of the RLC PDU from the MAC PDU, certain information is needed to indicate the amount of data contained in each logical channel. Therefore, it is preferable to include information indicating the amount of data corresponding to individual logical channels, or other information indicating identifiers (IDs, IDs) of logical channels.

Preferably, the receiving side extracts RLC PDU information using the logical channel ID contained in the MAC PDU header and the data block size information of each logical channel. The receiving party then transmits the selected information to the corresponding RLC entities.

The operation of the MAC and RLC levels in accordance with the present invention will be described below with additional reference to FIG. The MAC PDU includes a MAC header and an RLC PDU. An RLC PDU includes RLC SDU data and segment information associated with an RLC SDU received from a higher layer. The segment information performs a function similar to the RLC header. Preferably, the segment information includes RLC SDU boundary information, for example, in one RLC PDU. The MAC header indicates the size of each RLC PDU contained in the MAC PDU, and information about which one of the plurality of RLC objects or logical channels corresponds to each RLC PDU.

If the management information (eg, status report information) for indicating the reception status is contained in the MAC PDU, this management information is contained in a separate RLC PDU. Accordingly, the MAC header may indicate the presence of control information. In this case, the control information may, by way of example, be implemented using a method of using a logical channel ID having a special meaning.

5 is a block diagram illustrating a MAC PDU format in accordance with one embodiment of the present invention. Preferably, the MAC PDU is based on an RLC PDU received from an upper RLC entity.

As shown in FIG. 5, the RLC ID field indicates that the corresponding RLC PDU has been received through a specific logical channel or from a specific RLC entity. The Length field indicates the size of each RLC PDU. The F field indicates whether the following values are obtained using combinations of the RLC ID field, the Length field and the F field, or whether the following values are real RLC PDUs.

It should be noted that data may be unexpectedly lost in the physical channels of communication systems. Compared to a conventional system, the physical layer of a UTRAN system can more correctly transmit data from the transmitting side to the receiving side. However, the probability of an error in data transfer is not completely resolved in the UTRAN system. In particular, the greater the distance from the UE to the eNode-B, the higher the frequency of data loss of the UE.

Therefore, in the communication system in accordance with the present invention, a special control method is required, for example, in cases where TCP data requires error-free transmission or signal transmission data. Accordingly, the communication system may use the AM mode. As for the TCP packet, the TCP packet size can be expanded up to 1500 bytes. Therefore, if a TCP packet made in the form of an RLC SDU is transmitted to the RLC, the RLC entity can recombine the TCP packet within a certain size allowed by the lower layer (i.e., the MAC layer) and can transmit the recombined TCP packet to the destination.

Several RLC PDUs generated as a result of the above recombination are transmitted to the receiving side through the physical layer. However, if at least one RLC PDU corresponding to one RLC SDU is not received by the receiving side, the receiving side informs the transmitting side that the RLC PDU has not been received. In this case, if the transmitting side retransmits the entire RLC SDU associated with the lost RLC SDU, a large amount of radio resources will be wasted.

For example, 1,500 byte RLC SDUs are divided into ten RLC SDUs, each of which has 150 bytes. If a single RLC PDU among 10 RLC PDUs is not correctly received at the receiving end, the entire RLC SDUs are retransmitted in accordance with the above situation. Accordingly, 1,400 bytes of data will be transferred in vain. In this case, there is a need to retransmit at the RLC PDU level.

Wireless media obtained when you want to retransmit RLC PDUs may differ from the media used during the initial transmission of RLC PDUs. For example, if the RLC PDU is transmitted initially, the corresponding RLC entity may transmit 200 byte data for a single time. However, when an RLD PDU is retransmitted, the corresponding RLC entity may unexpectedly transmit data of only 50 bytes in size per unit time. In this case, the RLC PDU cannot retransmit unchanged. In particular, an RLC PDU having a source format cannot be retransmitted to a desired destination. To solve this problem, in one embodiment of the present invention, the source RLC PDUs are divided into several RLC subPDUs. Preferably, the present invention makes it possible for the receiving side to receive reception status information from the receiving side after the transmitting side transmits an RLC PDU. After that, the transmitting side performs a retransmission in accordance with the radio resources currently allocated to the transmitting side.

6 is a flowchart illustrating a signal transmission method of a mobile communication system in accordance with one embodiment of the present invention. As shown in FIG. 6, the transmitting side transmits the first RLC PDU data to the receiving side (S60). The receiving side receives the first data and transmits transmission / reception acknowledgment information (eg, ACK / NACK signals) for the RLC PDUs and reception status information for the received first data (S61).

If the first data is to be retransmitted, the transmitting side determines which one of the plurality of RLC PDUs has not been received by the receiving side using the transmit / receive acknowledgment information received from the receiving side. After that, the transmitting side recognizes the amount of radio resources available for retransmission (S62).

If the RLC PDU can be retransmitted using the available amount of radio resources, retransmission of the RLC PDUs is performed (S63). However, if the RLC PDU cannot be retransmitted using the available amount of radio resources, the configuration of the RLC PDUs is changed and used in the form of two or more RLC subPDUs (S64) so that the RLC subPDUs can be transmitted using the available amount of radio resources (S65) .

In other words, if the RLC PDU data needs to be retransmitted and the amount of radio resources allocated for the end of the transmission is less than the size of the original RLC PDU, the transmitting side changes the configuration of the RLC PDU in the form of two or more RLC subPDUs (S64) and transmits these RLC subPDUs to the receiving side (S65). Preferably, each RLC entity configures a predetermined amount of radio resources allocated by a lower layer.

The amount of radio resources indicates the maximum amount of data that can be transmitted by the transmitting side. The transmitting side also includes an RLC of the transmitting side.

If there is a need to reconfigure the RLC PDUs using scheduling information or other information loaded into the transmit / receive acknowledgment information, the configuration of the RLC PDUs is changed to two or more RLC subPDUs so that the RLC subPDUs can be transmitted to the receiving side. The transmitting side may also change the configuration of the RLC PDUs in the form of two or more RLC subPDUs, provided that any one of the transmitted RLC PDUs has not arrived at the receiving side.

In one aspect of the present invention, scheduling information or transmit / receive acknowledgment information received by the receiving side from the transmitting side denotes the size of the RLC subPDUs reconfigured by the transmitting side. Preferably, scheduling information is transmitted from the eNode-B to the UE to indicate which of the plurality of UEs will use a given amount of radio resources at a given point in time. In particular, scheduling information denotes volume information of radio resources to be used by a specific UE, and time information that will be used by a specific UE in accordance with radio resources having volume information.

Preferably, the transmit / receive confirmation information is transmitted from the receiving side to the transmitting side to indicate the correct reception of one of the plurality of PDUs or SDUs on the receiving side. Transmission / reception acknowledgment information also indicates no reception of one of the plurality of PDUs or SDUs at the receiving side. The receiving side recognizes whether the received data unit is an RLC PDU or an RLC subPDU. If the receiving side cannot recognize the data block, the receiving side reassembles the RLC SDU by linking the unmatched data into a single bundle. Otherwise, the order of the data modules contained in the same RLC SDU may be changed from the original order.

In order to distinguish between RLC PDUs and RLC subPDUs, an additional field that allows you to distinguish between RLC PDUs and RLC subPDUs can be added to the header of the data block transmitted between the RLC and MAC. In accordance with the value of the additional field, the receiving RLC may determine whether the data block is received from a lower MAC, RLC PDU, or RLC subPDU. Thus, when the data block is transmitted to the low MAC, the transmitting side RLC entity determines whether the transmission data is RLC PDU or RLC subPDU data, and can appropriately set the PDU / subPDU discriminator for the header of the data block.

Preferred embodiments of the RLC subPDU will be described below with reference to the drawings. It should be noted that the following RLC subPDU formats are not limited to the preferred embodiments of the present invention and can also be used in other examples, if necessary.

7 is a diagram illustrating a data transmission method of a mobile communication system in accordance with one embodiment of the present invention. As shown in FIG. 7, the first block 70 includes three IP packets. Preferably, these three IP packets are considered as RLC SDUs in terms of an RLC entity. Preferably, the sizes of the individual IP packets for use in one embodiment of the present invention are 500 bits, 600 bits, and 300 bits, respectively.

The second block 71 indicates how to configure the RLC PDU using three IP packets. Here, it is assumed that the allowed RLC PDU sizes in wireless environments during initial transmission are 300 bits, 400 bits, and 700 bits, respectively. In addition, the RLC PDU includes several header fields.

A detailed description of the individual header fields in accordance with the present invention is given below. The stream ID field (queue ID) indicates which one of the plurality of RBs or one of the plurality of RLC entities is associated with the RLC PDU. Indeed, a single UE includes several RBs having different QoS and characteristics, or several RLC entities having different QoS and characteristics. Therefore, the stream ID field separates individual RBs from other RBs.

The Transmission Sequence Number (TSN) field helps change the layout or controls the retransmission of the received RLC PDUs. Preferably, the TSN value is increased by a certain amount of “1” whenever a new RLC PDU is generated. Thus, the TSN indicates the order of the individual RLC PDUs in one RLC entity.

The length indicator field (LI) indicates the boundary of the RLC SDU. Thus, if a single RLC PDU includes two parts of an RLC SDU, the receiving end can correctly separate these RLC SDUs using the RLC SDU boundary information.

The third block 72 indicates how to configure the RLC PDU in the form of an RLC subPDU. When the receiving side informs the transmitting side of the non-acceptance of a specific RLC PDU using the ARQ operation, it is required that the transmitting side retransmit the RLC PDU. However, at a certain point in time at which a retransmission is required, the amount of radio resources available for use by the lower layer of the transmitting side may not be sufficient to transmit the RLC PDU. Accordingly, it is preferable to split the RLC PDUs into RLC subPDUs or change the configuration of the RLC PDUs in the form of RLC subPDUs so that the RLC subPDUs can be transmitted to the receiving side using available radio resources.

Below, with reference to FIG. 7, a method for changing the configuration of the second RLC PDU of the second unit 71 in the form of a plurality of RLC subPDUs will be described. Here, it is assumed that the amount of data that can be transmitted over a unit time is based on wireless media when retransmitted from the lower end (or lower level) is 100 bits, 200 bits and 100 bits, respectively. Therefore, the RLC PDUs to be retransmitted are configured in the form of RLC subPDUs for which 100 bits, 200 bits and 100 bits are sequentially assigned.

Preferably, the transmitting side informs the receiving side of the transmission when it transmits an RLC PDU or an RLC subPDU. Thus, in order to separate the RLC subPDUs from the RLC PDUs, an LI field having a specific value can be used. 7, a special LI field is used during RLC subPDU transmission. Therefore, whenever a receiving side receives a special LI field, the receiving side determines that the received data unit is an RLC subPDU, and performs the corresponding operation.

Typically, the receiving side uses the LI field to determine the boundary of the RLC SDU. However, if the receiving side receives an RLC PDU with an LI field set to a specific value, the receiving side considers the received RLC PDU as an RLC subPDU. In this case, to identify the source RLC PDU associated with the received RLC subPDU, the TSN field of the RLC subPDU is set to the same value as the TSN field of the source RLC PDU. Therefore, the receiving side can recognize the location information of the received RLC subPDUs, associated RLC subPDUs or associated RLC SDUs.

Accordingly, if a single RLC PDU is divided into several RLC subPDUs, additional information is required so that the receiving party can determine the order of the received RLC subPDUs. Thus, preferably for this purpose, the subPDU information field is used.

The subPDU information field indicates whether a particular RLC subPDU is located at the end of its corresponding RLC subPDU and relative position information of a specific RLC subPDU among the associated RLC subPDUs. For example, as shown in the third block 72 in FIG. 7, the subPDU information field of the third RLC subPDU indicates that the particular RLC subPDU is the final RLC subPDU associated with the RLC subPDU, and that the specific RLC subPDU is the third RLC subPDU among the RLC subPDU, associated with an RLC PDU.

Although all RLC subPDUs are retransmitted from the transmitting side to the receiving side, as described above, the receiving side may incorrectly receive some parts of the RLC subPDUs. Accordingly, RLC subPDUs can be further divided into smaller data units. However, if the probability of losing all RLC PDUs and associated RLC subPDUs is extremely low, it is preferable not to further divide the RLC subPDUs.

FIG. 8 is a diagram illustrating a data transmission method of a mobile communication system in accordance with one embodiment of the present invention. As shown in FIG. 8, the first block 80, the second block 81, and the third block 82 are structurally similar to the first, second, and third blocks shown in FIG. However, additional fields are presented in FIG.

The frame break indicator (S) field indicates that the received data unit is an RLC subPDU for an RLC PDU. Preferably, if the S field is set to "Y", then the corresponding data unit is an RLC subPDU.

The Length Increment Indicator (LEX) field indicates whether the next field is an LI or RLC SDU field. If the LEX field is set to "Y", then the next field is the LI field. The subPDU information field is used when the receiving side changes the configuration of the RLC subPDU.

9 is a diagram illustrating a data transmission method of a mobile communication system in accordance with one embodiment of the present invention. As shown in FIG. 9, the first block 90, the second block 91, and the third block 92 are structurally similar to the first, second, and third blocks of FIGS. 7 and 8. However, additional fields are shown in FIG. 9.

The sequence number (SN) field indicates the data stream of the corresponding RLC PDU or location information in the logical channel. The control / data / subframe (C / D / S) field indicates whether the corresponding RLC PDUs represent ARQ RLC PDUs for transmitting data, ARQ RLC control PDUs for transmitting control information, or ARQ RLC subPDUs that are reconfigured when retransmitted ARQ RLC PDU.

The full / partial (C / P, R / H) field indicates whether the first part of the PDU data is equal to the first part of the associated SDU. The C / P field also indicates which of the plurality of SDUs corresponds to the end of the RLC PDU. An exemplary case in which the C / P field contains two bits is as follows.

For example, if the value of the C / P field is “00”, the initial part of the PDU is equal to the initial part of the SDU, and the end of the PDU is equal to the end of the SDU. If the value of the C / P field is “01”, the initial part of the PDU is equal to the initial part of the SDU, and the end of the PDU is not equal to the end of the SDU. If the value of the C / P field is “10”, the initial part of the PDU is not equal to the initial part of the SDU, and the end of the PDU is equal to the end of the SDU. If the value of the C / P field is "11", the initial part of the PDU is not equal to the initial part of the SDU, and the end of the PDU is not equal to the end of the SDU.

The next field (F) indicates whether the next field is an LI field or data. The length indicator field (LI) indicates the boundary of the SDU contained in the PDU. The subframe sequence number field (sSN) indicates location information of a particular subPDU among the plurality of associated subPDUs. The rest field (RM) indicates the presence or absence of associated subPDUs after a specific subPDU.

As is clear from the above description, the present invention provides a method for transmitting data of a mobile communication system. If a particular data block is required to be retransmitted, but there is no sufficient radio resource for transmitting this data block, the present invention changes the configuration of the data block for transmitting this data block using the available radio resources. Preferably, the present invention retransmits only what is needed. Therefore, the data transfer efficiency is increased and the time to disconnect a user service or UE is reduced.

Although the present invention has been described in the context of mobile communications, it can also be used in any wireless communication systems that use mobile devices such as PDAs and laptop computers equipped with wireless capabilities. In addition, the use of certain terms to describe the present invention should not limit the scope of the present invention to a specific type of wireless communication system, such as UMTS. The present invention is also applicable to other wireless communication systems that use different radio channel interfaces and / or physical layers, for example, TDMA (TDMA, time division multiple access), CDMA (CDMA, code division multiple access), FDMA (FDMA, frequency division multiple access), WCDMA (WDMCR, wideband code division multiple access), etc.

Preferred embodiments may be embodied as a method, device, or product made using standard programming techniques and / or engineering techniques to produce software, firmware, hardware, or any combination thereof. The term "product of manufacture", as used here, refers to code or logic circuits embodied in hardware logic (for example, an integrated circuit, a user programmable gate array, a gate array (FPGA), a problem-oriented integrated circuit (ASIC, SEIS), etc.), or to a computer-readable storage medium (for example, a magnetic recording medium (for example, a hard disk drive, floppy disks, tapes, etc.), an optical drive (CD-ROM, optical drives), etc.), volatile and non-volatile memory devices (e.g. EEPROM (EEPROM, electrically erasable programmable read-only memory), ROM (ROM, read-only memory), PROM (ROM, programmable read-only memory), RAM (RAM, random access memory), DRAM (RAM, dynamic random access memory), SRAM (RAM, static random access memory)), built-in software (programmable logic, etc.).

The processor accesses and executes the code read from the computer-readable storage medium. The code in which the preferred embodiments are implemented can be further accessed via a transmission medium or from a file server via a network. In such cases, the product of manufacture, in which the code may be embodied, may contain data transmission media, such as a network transmission line, a wireless transmission medium, signals propagating through space, radio waves, infrared signals, etc. Of course, it will be understood by a person skilled in the art that many modifications can be made in this configuration without going beyond the scope of the present invention, and that the product can contain any medium that carries information known in the art.

It will be apparent to those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Industrial applicability

The present invention can be applied in a mobile communication system.

Claims (18)

1. A method for retransmitting a data block in a mobile communication system, comprising the steps of:
determining whether the first data block fits within the volume of the data block indicated by the lower layer if the first data block has not been successfully transmitted to the receiving side;
segmenting the first data block to form a second data block if the first data block does not fit in the volume of the data block indicated by the lower level, while the second data block fits in the volume of the data block indicated by the lower level; and
retransmit the second data block to the receiving side. 2. The method according to claim 1, further comprising the step of retransmitting the first data block to the receiving side if the first data block fits within the volume of the data block indicated by the lower layer. 3. The method according to claim 1, wherein the step of segmenting the first data block to form the second data block comprises the step of converting only the data field of the first data block into the data field of the second data block. 4. The method according to claim 3, in which the step of segmenting the first data block to form the second data block comprises the step of setting the header of the second data block. 5. The method of claim 4, wherein the header of the second data block includes a field indicating that the second data block is segmented from the first data block. 6. The method according to claim 4, in which the header of the second data block includes a field indicating the position of the second data block within the first data block. 7. The method according to claim 6, in which the header of the second data block includes a field indicating the initial position of the second data block within the first data block. 8. The method according to claim 4, in which the header of the second data block includes a field indicating whether the second data block is the last second data block within the first data block. 9. The method of claim 1, wherein the first data unit is a protocol data unit (PDU) of an acknowledgment mode (AMD) data. 10. A device for retransmitting a data block in a mobile communication system, comprising
means for determining whether the first data block fits within the volume of the data block indicated by the lower level if the first data block has not been successfully transmitted to the receiving side;
means for segmenting the first data block to form a second data block if the first data block does not fit in the volume of the data block indicated by the lower level, while the second data block fits in the volume of the data block indicated by the lower level; and
means for retransmitting the second data block to the receiving side. 11. The device according to claim 10, further comprising means for retransmitting the first data block to the receiving side if the first data block fits within the volume of the data block indicated by the lower level. 12. The device according to claim 10, in which the means for segmenting the first data block to form the second data block contains means for converting only the data field of the first data block into the data field of the second data block. 13. The device according to item 12, in which the means for segmenting the first data block to form the second data block contains means for setting the header of the second data block. 14. The device according to item 13, in which the header of the second data block includes a field indicating that the second data block is segmented from the first data block. 15. The device according to item 13, in which the header of the second data block includes a field indicating the position of the second data block within the first data block. 16. The device according to clause 15, in which the header of the second data block includes a field indicating the initial position of the second data block within the first data block. 17. The device according to item 13, in which the header of the second data block includes a field indicating whether the second data block is the last second data block within the first data block. 18. The device according to claim 10, in which the first data unit is a protocol data unit (PDU) with confirmation mode data (AMD).

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