KR20070078331A - Method and apparatus transmitting scheduling information in communication system - Google Patents

Abstract

A method and an apparatus for transmitting SI(Scheduling Information) in a mobile communication system are provided to allow a base station to obtain information required for scheduling by transferring SI of a terminal to a cell belonging to a serving RLS(Radio Link Set) when several RLSs are formed at the terminal in a soft handover area. When SI is generated, the SI is configured as a MAC(Media Access Control)-e PDU(Protocol Data Unit) and transmitted to cells of a serving RLS(410) and cells of a non-serving RLS(415). When NACK with respect to the MAC-e PDU arrives from the cells of the serving RLS, the MAC-e PDU is re-transmitted. When the number of re-transmissions of the SI data reaches a maximum re-transmission limit, it is determined that the transmission of the SI has failed, and the SI is inserted into a new MAC-e PDU and then transmitted.

Description

METHOD AND APPARATUS TRANSMITTING SCHEDULING INFORMATION IN COMMUNICATION SYSTEM}

1 is a diagram schematically illustrating the operation of a general EDCH communication system.

2 is a diagram illustrating a primary RLS and a secondary RLS.

3 is a diagram illustrating an operation of transmitting scheduling information in a soft handover area according to the prior art.

4 is a diagram illustrating an operation of transmitting scheduling information in a soft handover area according to an embodiment of the present invention.

5 is a diagram illustrating the operation of a terminal according to the first embodiment of the present invention;

6 is a diagram illustrating the operation of a terminal according to a second embodiment of the present invention;

7 is a diagram illustrating a structure of a terminal according to an embodiment of the present invention.

The present invention relates to a mobile communication system for transmitting packet data through uplink, and more particularly, to a method and apparatus for transmitting scheduling information to a desired cell when a user terminal is located in a soft handover area.

Asynchronous wideband code division multiple access (WCDMA) communication systems employ an enhanced uplink dedicated channel (hereinafter referred to as "E-DCH" or "EUDCH"). use. The E-DCH is a channel proposed to improve the performance of packet transmission in reverse communication in an asynchronous code division multiple access communication system.

The mobile communication system supporting the E-DCH maximizes the efficiency of uplink transmission by using a Node B-controlled scheduling technique and a hybrid automatic retransmission request (HARQ) technique. In the base station scheduling scheme, a base station Node B receives a channel state and a buffer state of a user equipment (hereinafter referred to as “UE”), and controls reverse transmission of the UEs based on the received information. will be. The base station allows efficient use of limited uplink transmission resources by allowing large amounts of data transmission to UEs in good channel conditions and minimizing the amount of data transmission for UEs in poor channel conditions. The HARQ technique increases the transmission success rate compared to the transmission output by executing HARQ between the UE and the base station. The base station performs soft combining with the retransmitted data block without discarding the data block in which an error occurs during the transmission through the HARQ technique, thereby increasing the probability of successful reception of the data block.

1 illustrates the basic operation of an EDCH.

When data to be transmitted is generated, the UE 105 transmits scheduling information (hereinafter, referred to as “SI”) to the base station 110 in step 115. The SI includes an amount of data stored in the UE 105, a priority of the data, and channel state information of the UE.

The base station 110 performs scheduling based on the information included in the SI, and allocates a resource grant to the UE 105 in step 120. The transmission resource is the size of the transmission output that the UE can use for data transmission.

The UE 105 transmits data using the transmission resource allocated from the base station 110 in step 125. In this case, the data is referred to as a MAC-e Protocol Data Unit (PDU). In the MAC-e PDU, data of a higher layer is stored, and in some cases, SI is also stored. The MAC-e PDU is transmitted in HARQ between the UE 105 and the base station 110. That is, if an error exists in the MAC-e PDU transmitted by the UE 105, the base station 110 transmits a NACK signal in step 130, and the UE 105 receiving the NACK signal transmits the MAC-e PDU in step 135. Resend. Then, the base station 110 soft-combines the retransmitted MAC-e PDU with the original MAC-e PDU and checks whether there is an error and transmits an ACK or NACK signal to the terminal. The UE 105 repeats the operation until an error is cleared in the MAC-e PDU so that an ACK signal is received by the UE 105 or the number of retransmissions reaches a predetermined allowable maximum retransmission number of the MAC-e PDU. .

In addition, the UE 105 should also periodically transmit the SI to the base station 110. If there is higher layer data at the time when the SI should be transmitted, the UE 105 multiplexes the higher layer data and the SI at step 145 or 155 to perform MAC. -e Configure and send the PDU. At this time, the MAC-e PDU multiplexed with the SI is also transmitted to the base station 110 through the same HARQ process.

2 is a diagram illustrating a configuration of a radio access network in a general UMTS system.

In the UTSM communication system, a radio access network includes an RNC and Node Bs 205 and 210, and one Node B controls several cells. The UE 240 is wirelessly connected to the cell, and the radio connection between the UE 240 and the cell is called a radio link 245, 260, 265, 270, 275. Also, a set of radio links 250 and 255 between cells belonging to one Node B and an arbitrary UE is called a radio link set (RLS).

As described above, the Node B is responsible for scheduling for the UE. As shown in FIG. 2, when the UE is located in the handover area, the Node B has a relationship with several Node Bs at the same time. At this time, a Node B in charge of scheduling for the UE is called a primary Node B, and an RLS between the primary Node B and the UE is called a primary RLS. The remaining RLSs other than the primary RLS are referred to as non-serving RLS.

The SI transmitted by the UE must be delivered to the primary Node B, which means that an ACK for the SI must be received from one of the cells belonging to the primary RLS.

Then, the operation of the UE for delivering the SI to the primary Node B when having multiple RLS of the UE will be described.

As described above, only the upper layer data may be stored in the MAC-e PDU, the upper layer data and the SI may be stored together, or only the SI may be stored. However, SI must be received by cells belonging to the primary RLS so that the SI is also transmitted to the primary Node B. However, since the upper layer data is collected in the RNC, whether the cells belong to the primary RLS or the cells belonging to the secondary RLS, they need only be received by any cell having a radio link with the UE. If the SI and higher layer data are stored together in the MAC-e PDU, and the MAC-e PDU is successfully received only by the cell belonging to the secondary RLS, the UE sends the following two to transmit the SI to the cells belonging to the primary RLS. It can take one of three actions.

Continuously retransmit MAC-e PDU until receiving ACK signal from cell belonging to primary RLS

If an ACK signal is received from a cell belonging to the secondary RLS, the corresponding MAC-e PDU is discarded, and the SI is stored in a new MAC-e PDU and transmitted.

In general, considering that the upper layer data is much larger than the SI, since the first operation is inefficient, the current UMTS communication system generally uses the second operation.

3 illustrates a process of transmitting scheduling information in the soft handover region according to the prior art.

Referring to FIG. 3, when the UE 305 transmits a MAC-e PDU in which SI and higher layer data are multiplexed, the MAC-e PDUs are cells belonging to the primary RLS in steps 320 and 325 due to the nature of the CDMA communication system. And delivered to cells 315 belonging to 310 and secondary RLS. The cells send feedback information based on a CRC operation result.

For example, if a cell belonging to the primary RLS transmits a NACK signal in step 350 and a cell belonging to the secondary RLS transmits an ACK signal in step 355, this means that upper layer data is successfully transmitted, but SI is transmitted to the primary Node B. In this case, the UE 305 attempts SI retransmission in operation 360 (360).

As described above, the UE receives an ACK signal from a cell belonging to the secondary RLS for any packet, and if the SI includes the SI, the SI is inserted into the new MAC-e PDU and retransmitted, whereby the SI belongs to the primary RLS. To be delivered to the cell.

However, if the SI cannot be delivered to the cell belonging to the primary RLS, as well as receiving the ACK signal from the cell belonging to the secondary RLS as described above, even though the MAC-e PDU has been retransmitted by the maximum allowable retransmission limit, It includes a case in which an ACK signal is not received. Therefore, even if the received MAC-e PDU is not successfully transmitted to the cell belonging to the primary RLS due to the maximum number of retransmissions allowed, the SI is not delivered to the primary Node B.

An object of the present invention is to provide a method and apparatus for allowing a terminal to retransmit an SI to a base station not only when receiving an ACK from a cell belonging to the secondary RLS but also when the SI transmission fails due to a limit of the maximum allowable number of retransmissions. .

The present invention provides a method for transmitting scheduling information by a mobile station in a mobile communication system for transmitting packet data through uplink. When scheduling information is generated, the scheduling information is configured as a MAC-e PDU, and the cells belonging to the primary RLS and the secondary RLS. Transmitting to the cells belonging to the RLS, retransmitting the MAC-e PDU when the NACK for the MAC-e PDU arrives from a cell belonging to the main RLS, and retransmitting the scheduling information data. If the number of retransmissions is reached, determining that the transmission of the scheduling information has failed, and inserting the scheduling information into a new MAC-e PDU and transmitting.

In addition, the present invention is a terminal for transmitting scheduling information in a mobile communication system for transmitting packet data through the uplink, a scheduling information reporting unit for generating scheduling information at regular intervals, and receiving the scheduling information from the scheduling information reporting unit; A HARQ processor for receiving the MAC-e PDU from the multiplexing / MAC-e PDU generating unit configured with a MAC-e PDU, and transmitting the MAC-e PDU from the multiplexing / MAC-e PDU generating unit to cells belonging to the primary RLS and cells belonging to the secondary RLS The HARQ processor may report that the scheduling information transmission has failed when the number of retransmissions of the MAC-e PDU reaches a preset maximum number of retransmissions, and generates the multiplexing / MAC-e PDU. The unit configures the failed transmission information into a new MAC-e PDU under the control of the scheduling information report unit. And transmitting to the cells belonging to the primary RLS and the cells belonging to the secondary RLS through the HARQ processor.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

4 illustrates an operation of transmitting scheduling information by a UE to a base station in a soft handover area according to an embodiment of the present invention.

The UE 405 performs EDCH communication with cells 410 belonging to the primary RLS and cells 415 belonging to the secondary RLS. As described above, the number of cells belonging to the primary RLS and the number of cells belonging to the secondary RLS may be two or more. However, in FIG. 4, only one cell is present for each RLS for convenience.

If an SI occurs at any point in time, the UE 405 multiplexes the SI with higher layer data to the cells 410 belonging to the primary RLS and the cells 415 belonging to the secondary RLS in steps 420 and 425. The cells 410 of the primary RLS and the cells 415 of the secondary RLS receive the MAC-e PDU in which the SI and the higher layer data are multiplexed, and examine the CRC of the MAC-e PDU to determine whether there is an error. Accordingly, ACK or NACK information is transmitted to the UE 405.

The UE 405 continues to retransmit the MAC-e PDU until it receives an ACK from the cell 410 belonging to the primary RLS or the cell 415 belonging to the secondary RLS.

However, due to poor channel conditions, as shown in FIG. 4, the NACK signal is continuously received from the cell 410 belonging to the primary RLS and the cell 415 belonging to the secondary RLS, and at step 460, the MAC-e PDU is retransmitted at any time. When the number of times reaches the maximum allowable number of retransmissions, the terminal abandons the transmission of the MAC-e PDU. However, even in this case, the UE 405 multiplexes the SI to the new MAC-e PDU in step 465 and retransmits it.

FIG. 5 illustrates an operation of a UE when only an SI is stored in a MAC-e PDU according to an operation of the UE according to the first embodiment of the present invention.

As shown in FIG. 5, when SI occurs in step 505, the UE configures the SI as a MAC-e PDU in step 510 and transmits the SI through a HARQ processor. In step 515, the UE checks whether an ACK for the MAC-e PDU arrives from a cell belonging to the primary RLS.

As a result of the check, when the ACK for the MAC-e PDU arrives from the cell belonging to the primary RLS, the SI is delivered to the cell belonging to the primary RLS, and thus the UE proceeds to step 520 to terminate the process. In addition, if the ACK for the MAC-e PDU has not arrived from the cell belonging to the main RLS, the process proceeds to step 525.

In step 525, the UE checks whether an ACK for the MAC-e PDU arrives from a cell belonging to the secondary RLS. If an ACK for the MAC-e PDU arrives from the cell belonging to the secondary RLS, the UE has not delivered the SI to the cell belonging to the primary RLS. Therefore, the UE proceeds to step 535 and the scheduling information reporting unit of the UE (SI Reporting Function; Inform the fact that the SI transmission has failed. In step 540, the SIRF of the UE inserts and transmits the SI into a new MAC-e PDU. In this case, the SI inserted into the new MAC-e PDU may be an SI at the time of transmitting the new MAC-e PDU or an SI previously failed to transmit. The SIRF will be described in detail later.

On the other hand, if the ACK for the MAC-e PDU has not arrived from the cell belonging to the cell belonging to the secondary RLS in step 525, the UE proceeds to step 530 to check whether the number of retransmissions has reached the maximum allowed retransmission number of the SI.

If the number of retransmissions has not reached the maximum allowable retransmission number of the SI, the process returns to step 510 to perform retransmission for the MAC-e PDU. In addition, if the check result shows that the number of retransmissions has reached the maximum allowable retransmission of the SI, since the MAC-e PDU can no longer be retransmitted, the UE proceeds to step 535 and notifies the SIRF that the SI transmission has failed. In the step, the SI is inserted into a new MAC-e PDU and transmitted.

Meanwhile, in FIG. 5, when the NACK signal is received from the primary RLS in step 515, the process proceeds to step 530 after confirming whether the ACK signal is received from the secondary RLS in step 525. It was explained by checking whether it reached. However, since the MAC-e PDU generated in the first embodiment of the present invention includes only the SI information and does not include the data received from the upper layer, in the first embodiment of the present invention, the ACK is received from the secondary RLS in step 525. The process of checking whether a signal has been received may be omitted, and the process may immediately proceed to step 530 to check whether the number of retransmissions has reached the maximum allowable retransmission number of the SI.

FIG. 6 illustrates an operation of a UE when an SI and higher layer data are transmitted by being multiplexed into one MAC-e PDU according to a second embodiment of the present invention.

As shown in FIG. 6, when an SI occurs in step 605, the UE multiplexes the SI with higher layer data in step 610 to form a MAC-e PDU and transmits the same through a HARQ processor.

Next, the UE checks whether an ACK for the MAC-e PDU arrives from the cell belonging to the primary RLS in step 615. As a result of the check, when the ACK for the MAC-e PDU arrives from the cell belonging to the primary RLS, since the SI is transmitted to the cell belonging to the primary RLS, the terminal proceeds to step 620 and terminates the process of transmitting the SI.

In addition, if the ACK for the MAC-e PDU does not arrive from the cell belonging to the cell belonging to the primary RLS, the UE proceeds to step 625. In step 625, the UE sends an ACK for the MAC-e PDU from the cell belonging to the secondary RLS. Check if it arrives.

If the check indicates that the ACK for the MAC-e PDU arrives from the cell belonging to the secondary RLS, since the SI has not been delivered to the cell belonging to the primary RLS, the UE proceeds to step 635 and notifies the SIRF that the SI transmission has failed. do. In step 640, the SIRF inserts and transmits the SI into a new MAC-e PDU.

If the ACK for the MAC-e PDU does not arrive from the cell belonging to the secondary RLS as a result of checking in step 625, the UE proceeds to step 630 and checks whether the number of retransmissions has reached the maximum allowable number of retransmissions of higher layer data.

If the number of retransmissions does not reach the maximum allowable retransmission number of higher layer data, the process proceeds to step 610 to perform retransmission for the MAC-e PDU. In addition, if the number of retransmissions reaches the maximum allowable number of retransmissions of higher layer data, the MAC-e PDU can no longer be retransmitted, so the UE proceeds to step 635 and informs the SIRF that the SI transmission has failed. Is inserted into a new MAC-e PDU and transmitted.

7 illustrates a structure of a UE according to an embodiment of the present invention.

Referring to FIG. 7, the UE includes an upper layer 705, a multiplexing / MAC-e PDU generation unit 710, a HARQ processor 715, and a scheduling information reporting function (SIRF) 720.

The SIRF 720 generates an SI and delivers the SI to the multiplexing / MAC-e PDU generation unit 710. The SIRF 720 may generate the SI at a predetermined cycle, and in the present invention, the SIRF 720 generates the SI even when a notification is received from the HARQ processor 715 that the SI transmission has failed.

The multiplexing / MAC-e PDU generating unit 710 receives upper layer data or SI from an upper layer or SIRF 720, configures the MAC-e PDU, and transmits the MAC-e PDU to the HARQ processor 715.

The HARQ processor 715 retransmits or flushes the MAC-e PDU according to ACK / NACK signals received from cells belonging to the primary RLS and cells belonging to the secondary RLS. That is, upon receipt of the NACK signal, the MAC-e PDU is discarded, and upon receipt of the ACK signal, the MAC-e PDU is retransmitted.

In addition, the HARQ processor 715 fails to transmit the MAC-e PDU including the SI due to the allowable maximum retransmission limit, or when the MAC-e PDU including the SI is received by a cell belonging to the secondary RLS, the SIRF 720 may be used. ) Is notified that the SI transmission failed.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

According to the present invention, when a plurality of RLSs are configured in a terminal in a soft handover area, the base station can obtain information necessary for scheduling by causing the SI of the terminal to be delivered to a cell belonging to the main RLS.

Claims (6)

In a method of transmitting scheduling information by a terminal in a mobile communication system transmitting packet data through an uplink, When the scheduling information is generated, configuring the scheduling information as a MAC-e PDU and transmitting the same to the cells belonging to the primary RLS and the cells belonging to the secondary RLS; Retransmitting the MAC-e PDU when a NACK for the MAC-e PDU arrives from a cell belonging to the primary RLS; And when the number of retransmissions of the scheduling information data reaches a preset maximum number of retransmissions, determining that the scheduling information transmission has failed and inserting the scheduling information into a new MAC-e PDU and transmitting the scheduling information. Transmission method. The method of claim 1, If the number of retransmissions of the scheduling information does not reach a preset maximum number of retransmissions, the method further includes returning to the process of transmitting the scheduling information to cells belonging to the primary RLS and cells belonging to the secondary RLS. How to send information. The method of claim 1, The process of transmitting the scheduling information to cells belonging to a primary RLS and cells belonging to a secondary RLS may include: And configuring only the scheduling information as the MAC-e PDU or multiplexing the scheduling information together with higher layer data to configure the MAC-e PDU. The method of claim 3, wherein In case that the scheduling information is multiplexed with higher layer data and configured as the MAC-e PDU, Checking whether an ACK for the MAC-e PDU has arrived from a cell belonging to the secondary RLS when a NACK for the MAC-e PDU arrives from a cell belonging to the primary RLS; If the ACK for the MAC-e PDU arrives from a cell belonging to the secondary RLS, determining that the scheduling information transmission has failed, and inserting the scheduling information into a new MAC-e PDU and transmitting the received information. How to send scheduling information. The method of claim 1, The transmitting of the scheduling information to cells belonging to a primary RLS and cells belonging to a secondary RLS may include transmitting the scheduling information through a HARQ processor. A terminal for transmitting scheduling information in a mobile communication system for transmitting packet data through an uplink, A scheduling information reporter for generating scheduling information at regular intervals; A multiplexing / MAC-e PDU generation unit configured to receive the scheduling information from the scheduling information report unit and configure a MAC-e PDU; A HARQ processor that receives the MAC-e PDU from the multiplexing / MAC-e PDU generation unit and transmits the MAC-e PDU to cells belonging to a primary RLS and cells belonging to a secondary RLS, When the number of retransmissions of the MAC-e PDU reaches a preset maximum number of retransmissions, the HARQ processor reports to the scheduling information reporter that the scheduling information transmission has failed. The multiplexing / MAC-e PDU generation unit configures the failed scheduling information as a new MAC-e PDU under the control of the scheduling information report unit and transmits the failed scheduling information to cells belonging to a primary RLS and cells belonging to a secondary RLS through the HARQ processor. Scheduling information transmission apparatus, characterized in that.

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