CN102447549B - Uplink synchronous hybrid automatic retransmission query method for mobile communication system - Google Patents

Abstract

The present invention provides a method for uplink synchronous hybrid automatic repeat request in a mobile communication system. The method includes: A. The base station judges that resource conflicts occur in the uplink processes of multiple user equipments according to the scheduling algorithm strategy. In the case of low user equipment allocating channel resources, an invalid uplink grant is generated, and the invalid uplink grant is sent to the user equipment with a lower service priority through downlink control information; B. The user equipment with a lower service priority receives The downlink control information determines that an invalid uplink authorization is received according to the downlink control information, cancels the retransmission of the uplink hybrid automatic repeat request process at a predefined position according to the invalid uplink authorization, and keeps the number of transmissions unchanged. By adopting the method of the present invention, it is possible to avoid the reduction of the available transmission times of the HARQ process when resolving the resource conflict, and reduce the occurrence probability of remaining HARQ errors.

Description

A Method for Uplink Synchronous Hybrid Automatic Repeat Request in Mobile Communication System

technical field

The invention relates to communication technology, in particular to an uplink synchronous hybrid automatic repeat request method in a mobile communication system.

Background technique

The uplink data transmission of the Long Term Evolution (LTE) system adopts the synchronous Hybrid Automatic Repeat Request (HARQ) technology, and supports both adaptive and non-adaptive retransmission methods.

FIG. 1 is a flowchart of a typical uplink synchronization hybrid automatic repeat request method in an existing LTE system. Now in conjunction with FIG. 1, the typical uplink synchronous hybrid automatic repeat request method of the existing LTE system is described, specifically as follows:

Step 101, perform resource assignment (Resource Assignment), the media access control (Media Access Control, MAC) layer on the eNB side sends resource assignment information to the HARQ entity on the eNB side, the resource assignment information includes configurations such as modulation mechanisms, uplink resources, and MCS information; step 102, perform resource assignment (Resource Assignment), the HARQ entity on the eNB side adds HARQ information to the resource assignment information and transmits it to the physical (PHY) layer on the eNB side; step 103, sends downlink control information (Downlink Control Information, DCI ) format (format) 0, the PHY layer on the eNB side sends the uplink grant (ULgrant) and HARQ information to the PHY layer on the UE side through the DCI format 0 used to indicate physical uplink shared channel (PUSCH) scheduling; step 104, send the physical Downlink control channel (PDCCH) information (Info), the PHY layer of UE side sends PDCCH information to UE side HARQ entity, and this control information includes uplink grant and HARQ information; Step 105, obtain uplink data instruction (ULdata ind); Step 106, Obtain uplink data (UL data); step 105 to step 106, the UE side HARQ entity obtains uplink data through the UE side MAC layer; step 107, perform HARQ operation (operation), the UE side HARQ entity obtains the uplink authorization, HARQ information and MCS and other configurations instruct the corresponding HARQ process (Process) on the UE side to perform HARQ operations; Step 108, send UL data, and the HARQ process on the UE side sends uplink data to the PHY layer on the UE side according to the instructions of the HARQ entity; Step 109, upload UL data, UE The physical layer on the eNB side sends UL data to the physical layer on the eNB side; Steps 110 to 114 are methods for the PHY layer, HARQ process, and HARQ entity on the eNB side to transmit uplink data to the MAC layer on the eNB side; Steps 115 to 119 are eNB based on whether Correctly receive the receipt and feed back HARQ feedback information (Feedback) to the UE side physical layer, the HARQ feedback information is Acknowledged (Acknowledged, ACK) information or non-acknowledged (Non-acknowledged, NACK) information; Step 120, send HARQ feedback information, UE side The PHY layer sends the HARQ feedback information to the UE side HARQ entity; step 121, data processing (Data process), the UE side HARQ entity sends the HARQ feedback information to the corresponding HARQ process of the UE side; the UE side HARQ process according to the received HARQ Feedback information is repeated according to the method of step 108 to step 109 Upload uplink data or transmit new data.

Since LTE uplink uses synchronous HARQ, the sending time domain position of each HARQ process on the UE side is predefined, that is to say, the first transmission and retransmission are performed on the same process, and the retransmission of MAC PDU and the first transmission There is a fixed time interval between retransmissions, and the corresponding HARQ process ID does not need to be clearly indicated during retransmission. At each predefined time domain position, as long as the cache of the HARQ process is not empty, or there is an uplink grant from the base station at this position, the HARQ entity will instruct the corresponding HARQ process to transmit new data, adaptive retransmission or non-adaptive Retransmission. Adaptive retransmission means that the resource, MCS and other configuration information applied to the retransmission of MAC PDU can be different from the corresponding configuration used in the first transmission, and needs to be notified by explicit scheduling signaling; non-adaptive retransmission refers to The retransmission of the MAC PDU uses the same resources and MCS as the first transmission, and no explicit scheduling signaling is used for notification.

FIG. 2 is a flow chart of a method for performing HAQR operations by an existing UE-side HARQ entity. Now in conjunction with FIG. 2, the method for performing HARQ operation by the existing UE-side HARQ entity is described:

Step 201: Determine the HARQ process corresponding to the subframe. In this step, the HARQ entity determines the HARQ process corresponding to the subframe according to the timing of the subframe. The specific determination method will not be repeated here; Step 202. Determine whether there is an uplink authorization to be indicated For the subframe, if yes, execute step 203, otherwise execute step 204, in which the HARQ entity judges whether an uplink authorization is indicated to the subframe, that is, determines whether an uplink authorization is indicated to the subframe The corresponding HARQ process, if yes, executes step 203, otherwise executes step 204; step 203, instructs the process to perform new data transmission or adaptive transmission according to the type of authorization, and then executes step 206, in which the HARQ entity according to the uplink authorization The type indicates that the HARQ process corresponding to the subframe performs new data transmission or adaptive transmission; step 204, judge whether the cache of the process is empty, if yes, perform step 206, otherwise perform step 205, in this step, the HARQ entity judges the Whether the cache of the HARQ process corresponding to the subframe is empty; step 205, instructing the process to perform non-adaptive retransmission, in which the HARQ entity instructs the HARQ process corresponding to the subframe to perform non-adaptive retransmission; step 206, Finish.

FIG. 3 is a flow chart of an existing method for sending uplink data by a HARQ process at the UE side. Now in conjunction with FIG. 3, the method for sending uplink data by the existing UE side HARQ process is described, specifically as follows:

Step 301, determine whether HARQ feedback is received, if yes, perform step 302, otherwise perform step 303, in this step, the HARQ process determines whether the HARQ feedback information from the eNB is received; step 302, set the HARQ feedback information as received Step 303, judge whether to receive the indication of HARQ entity, if yes, execute step 304, otherwise execute step 313; Step 304, judge whether the HARQ entity indication is new data transmission, if yes, execute step 305, otherwise execute step 306; Step 305, set the number of transmissions to 0 and transmit new data, then execute step 311; Step 306, judge whether the HARQ entity indication is adaptive retransmission, if yes, execute step 307, otherwise execute step 308; step 307 , add 1 to the number of transmissions and perform adaptive retransmission, then perform step 311; step 308, judge whether the HARQ feedback information is NACK, if yes, perform step 309, otherwise perform step 310; step 309, add 1 to the number of transmissions and Execute non-adaptive retransmission, then execute step 311; step 310, increase the number of transmissions by 1 and do not perform retransmission, then execute step 311; step 311, determine whether the maximum number of transmissions has been reached, if yes, execute step 312, otherwise execute step 313; Step 312, clear the data cached in the HARQ process, and then perform step 313; Step 313, end.

In the uplink scheduling process of the LTE system, when an uplink HARQ process of one UE is dynamically scheduled and an uplink HARQ process of another UE is semi-statically scheduled in a heavy uplink scenario, when the predefined When the time domain location is the same and the dynamically scheduled process occupies the retransmission resources of the semi-persistently scheduled process, the non-adaptive retransmission of the dynamically scheduled process may conflict with the new data or retransmission of the semi-persistently scheduled process. When such a resource conflict occurs, there may be no other resources for the dynamically scheduled process to perform adaptive retransmission due to the heavy load, so the base station needs to prohibit the retransmission of the dynamically scheduled HARQ process at the predefined time domain position . According to the methods in Fig. 1, Fig. 2 and Fig. 3, it can be seen that if the eNB wants to prohibit the transmission of the HARQ process of the UE at the predefined position, it needs to feed back the HARQ feedback information with the content of ACK to the HARQ process on the UE side in advance, but the HARQ process although When retransmission is not performed according to the HARQ feedback information whose content is ACK, the corresponding retransmission opportunity is reduced once (step 310 as shown in Figure 3), that is to say, although the HARQ process gives up at a predefined time domain position in a certain period of time transmission, but the number of transmissions at these predefined time domain positions will still be counted as the number of transmissions, which leads to the reduction of the actual number of transmissions available for the HARQ process. However, according to the existing uplink HARQ transmission mechanism, when the maximum number of HARQ transmissions is constant, the less the actual number of transmissions that can be used by a HARQ process, the greater the probability of remaining HARQ errors.

The existing LTE-A (LTE-Advanced) system's uplink synchronous HARQ method also has the problem of the uplink synchronous HARQ shown in Figure 1. In other words, the existing LTE system and LTE-Advanced In the uplink synchronous hybrid automatic repeat request method of system A, when resolving resource conflicts, the actual number of available transmission times of the HARQ process will decrease, and the probability of remaining HARQ errors will increase.

Contents of the invention

In view of this, the object of the present invention is to provide a method for uplink synchronous hybrid automatic repeat request in a mobile communication system, which can avoid the reduction of the number of available transmissions of the HARQ process and reduce the probability of remaining HARQ errors when resolving resource conflicts.

In order to achieve the above object, the technical solution of the present invention is specifically realized in the following way:

A method for uplink synchronous hybrid automatic repeat request in a mobile communication system, the method comprising:

A. The base station judges that resource conflict occurs in the uplink process of multiple user equipments according to the scheduling algorithm strategy, and in the case that channel resources cannot be allocated to the user equipment with a lower service priority, an invalid uplink grant is generated, and the invalid uplink grant is sent through the downlink control information granting uplink authorization to the user equipment with a lower service priority;

B. The user equipment with a lower service priority receives downlink control information, determines that an invalid uplink authorization has been received according to the downlink control information, cancels the retransmission of the uplink hybrid automatic repeat request process at a predefined position according to the invalid uplink authorization, and has transmitted The number of times remains unchanged, and the actual number of transmissions available for the uplink hybrid automatic repeat request process does not decrease.

In the above method, the method for the base station to generate an invalid uplink grant in step A is: the base station sets the resource block allocation and frequency hopping resource allocation fields in the format DCI format 0 of the downlink control information to resource indication values that cannot correspond to valid resources.

In the above method, the method for the base station in step A to send an invalid uplink grant to the user equipment with a lower service priority through the downlink control information is: the base station sends the resource block allocation and frequency hopping resource allocation fields to be set so that they cannot correspond to valid resources The resource indication value of DCI format 0 to the user equipment with a lower service priority.

In the above method, the method of determining the received invalid uplink grant according to the downlink control information in step B is: the uplink hybrid automatic repeat request HARQ entity included in the user equipment with lower service priority determines according to the received downlink control information If the resource indication value in the format of the downlink control information DCI format 0 corresponds to an invalid resource, it is determined that an invalid uplink authorization is received.

In the above method, the method of canceling the retransmission of the uplink hybrid automatic repeat request process at the predefined position according to the invalid uplink grant in step B is: the HARQ entity determines that there is an invalid uplink grant indication for the subframe, and then does not The frame performs the HARQ operation, and no indication is sent to the HARQ process corresponding to the subframe.

It can be seen from the above technical solution that in the uplink synchronous hybrid automatic repeat request method in the mobile communication system provided by the present invention, after the base station detects that there is a resource conflict when allocating channel resources to the uplink process of multiple UEs, it can choose not to send ACK Instead, send an invalid uplink grant to the UE with a lower service priority, so that the UE with a lower service priority no longer instructs the HARQ process corresponding to the UE to perform any operations, not only cancels the The uplink HARQ process retransmits data at a predefined time domain position, and the number of canceled transmissions will not be included in the number of transmitted times, which avoids the remaining time caused by the number of canceled transmissions still counted in the number of times transmitted in the existing method. The problem that the probability of occurrence of HARQ errors increases.

Description of drawings

FIG. 1 is a flowchart of a typical uplink synchronization hybrid automatic repeat request method in an existing LTE system.

FIG. 2 is a flow chart of a method for performing HAQR operations by an existing UE-side HARQ entity.

FIG. 3 is a flow chart of an existing method for sending uplink data by a HARQ process at the UE side.

Fig. 4 is a flow chart of the uplink synchronous hybrid automatic repeat request method in the mobile communication system of the present invention.

Detailed ways

In order to make the object, technical solution, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

In order to solve the problem in the prior art that the number of actual available transmissions of the HARQ process is reduced due to the resource conflict resolution process, the present invention provides a method for uplink synchronous hybrid automatic repeat request in a mobile communication system. After the algorithm strategy determines that the resources used by the uplink processes of multiple UEs have resource conflicts, and if other channel resources cannot be allocated to UEs with lower service priorities, the eNB cancels the uplink HARQ process at the predefined time domain position When retransmitting on the Internet, you can choose not to feed back the HARQ feedback information whose content is ACK to the UE with a lower service priority, but to send an invalid grant to the UE with a lower service priority, and the UE side that receives the invalid grant The HARQ entity clears the uplink authorization information of the HARQ process, and no longer sends an indication to the HARQ process to instruct the HARQ process to transmit new data, adaptive retransmission or non-adaptive retransmission, and the HARQ process keeps the number of transmissions unchanged, Therefore, the problem that the HARQ error occurrence probability increases due to the increase in the number of transmissions caused by the HARQ process not retransmitting the data is avoided.

Fig. 4 is a flow chart of the uplink synchronous hybrid automatic repeat request method in the mobile communication system of the present invention. As shown in FIG. 4 , the method for uplink synchronous hybrid automatic repeat request in the mobile communication system of the present invention can be applied to an LTE system or an LTE-A system, which is different from the method for uplink synchronous hybrid automatic repeat request in the existing LTE system shown in FIG. 1 Compared with the method, steps 401 to 407 of the method of the present invention are obviously different from steps 101 to 107 of the existing method, and the other steps are the same, and only the different steps are described here, specifically as follows:

Step 401: The MAC layer on the eNB side sends resource conflict information to the HARQ entity on the eNB side;

When the eNB allocates channel resources for the uplink process of multiple UEs, it judges whether the resources used by the uplink processes of multiple UEs conflict through the existing scheduling algorithm strategy. The lower UE's uplink process allocates other channel resources. If there is no suitable channel resource allocated to the UE's uplink process at this time, the MAC layer on the eNB side sends resource conflict information to the HARQ entity on the eNB side; otherwise, follow the steps The method in 101 allocates channel resources for uplink processes of multiple UEs.

The foregoing resource conflict information is sent through existing resource allocation information.

The resource conflict information is the information of the uplink process of the conflicting UE.

Step 402: the HARQ entity on the eNB side sends resource conflict information to the PHY layer on the eNB side;

The HARQ entity on the eNB side sends the resource conflict information to the PHY layer on the eNB side. Specifically, the above resource conflict information can be sent through existing resource allocation information.

Step 403: The PHY layer on the eNB side generates an invalid uplink grant according to the received resource conflict information, and sends the invalid uplink grant to the PHY layer on the UE side through DCI format 0;

The resource block allocation in the DCI format 0 of the present invention and the frequency hopping resource allocation field both include bits. In the existing LTE system, the resource physical resource blocks allocated for the uplink are continuous. The starting resource block position and the number of continuous resource blocks allocated to a UE can be determined by A value represented by bits is obtained, and this value is called a resource indication value (Resource Indication Value, RIV). Under all bandwidth configurations in existing LTE systems, not All RIVs that can be represented by a bit can correspond to a valid resource, and those RIVs that cannot correspond to valid resources are not used for normal resource allocation.

According to the received resource conflict information, the PHY layer on the eNB side sets the resource block allocation and frequency hopping resource allocation fields in DCI format 0 to resource indication values (Resource Indication Value, RIV) that cannot correspond to valid resources, and through DCI format 0 Send the invalid uplink grant to the PHY layer on the UE side. For example: eNB can use the The resource block allocation and frequency hopping resource allocation field of 1 bit is set to all "1". Since this value cannot correspond to a valid resource position, the UE receives Uplink authorization information with all bits set to "1" can be used to determine that the uplink authorization is an invalid uplink authorization.

Step 404: The PHY layer on the UE side sends an invalid uplink grant to the HARQ entity on the UE side;

The PHY layer on the UE side sends the received invalid uplink grant information (Info) transmitted through the existing physical downlink control channel (PDCCH) to the HARQ entity on the UE side.

Step 405: The HARQ entity on the UE side judges whether an invalid uplink grant is received, if yes, execute step 406, otherwise execute step 407;

The HARQ entity on the UE side passes the judgment Whether the RIV of bits corresponds to a valid resource is used to determine whether an invalid uplink grant is received, if yes, go to step 406, otherwise go to step 407.

Step 406: Do not perform HARQ operation on the subframe;

The HARQ entity at the UE side determines that the invalid uplink grant is indicated for the subframe, and does not perform the HARQ operation on the subframe.

Steps 407 to 409 are the same as the existing methods of steps 105 to 107, and will not be repeated here.

The difference between the HARQ operation method performed by the HARQ entity on the UE side of the present invention and the existing HARQ operation method shown in FIG. , otherwise, operate according to the method from step 201 to step 206 shown in FIG. 2 , which will not be repeated here.

The method for sending uplink data by HARQ at the UE side in the present invention is the same as the method for sending uplink data by HARQ at the UE side as shown in FIG. 3 , and will not be repeated here.

In a preferred embodiment of the present invention, after the base station detects that there is a resource conflict when allocating channel resources to the uplink processes of multiple UEs, it will no longer send ACK information to the HARQ entity, that is, no longer indicate the HARQ process through the HARQ entity Cancel the uplink HARQ process to retransmit data at the predefined time domain position, but send an invalid uplink grant to the HARQ entity, so that the HARQ entity controls the HARQ process without any operation, and the number of times the HARQ process has been transmitted remains unchanged at this time, In this way, not only the uplink HARQ process is canceled to retransmit data at the predefined time domain position, but also the number of canceled transmissions will not be counted into the number of transmitted times, which avoids that the number of times of transmission due to cancellation in the existing method is still counted into the number of times transmitted Therefore, the probability of occurrence of remaining HARQ errors increases. In addition, although the present invention uses the LTE system as an embodiment, since the LTE-A system basically inherits the HARQ method of the LTE system, the method of the present invention can also be applied to the LTE-A system to solve the problem existing in the LTE-A system. The number of available transmissions of the HARQ process decreases, and the probability of remaining HARQ errors increases.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (5)

1. A method for uplink synchronous hybrid automatic repeat request in a mobile communication system, characterized in that the method comprises: A. The base station judges that resource conflict occurs in the uplink process of multiple user equipments according to the scheduling algorithm strategy, and in the case that channel resources cannot be allocated to the user equipment with a lower service priority, an invalid uplink grant is generated, and the invalid uplink grant is sent through the downlink control information granting uplink authorization to the user equipment with a lower service priority; B. The user equipment with a lower service priority receives downlink control information, determines that an invalid uplink authorization has been received according to the downlink control information, cancels the retransmission of the uplink hybrid automatic repeat request process at a predefined position according to the invalid uplink authorization, and has transmitted The number of times remains unchanged, and the actual number of transmissions available for the uplink hybrid automatic repeat request process does not decrease. 2. The method according to claim 1, characterized in that the base station in step A generates an invalid uplink authorization method as follows: the base station sets the resource block allocation and frequency hopping resource allocation fields in the format DCI format 0 of the downlink control information into a resource indication value that does not correspond to a valid resource. 3. The method according to claim 2, characterized in that, in step A, the method for the base station to send the invalid uplink grant to the user equipment with lower service priority through the downlink control information is: the base station sends resource block allocation and hopping The frequency resource allocation field is set to DCI format 0 that cannot correspond to the resource indication value of the effective resource to the user equipment with a lower service priority. 4. The method according to claim 1, characterized in that the method for determining in step B that an invalid uplink grant has been received according to the downlink control information is: the uplink hybrid automatic repeat request contained in the user equipment with a lower service priority According to the received downlink control information, the HARQ entity determines that the resource indication value in the format DCI format 0 of the downlink control information corresponds to an invalid resource, and then determines that an invalid uplink grant is received. 5. The method according to claim 4, wherein the method of canceling the retransmission of the uplink hybrid automatic repeat request process at a predefined position according to the invalid uplink authorization in step B is: the HARQ entity determines that there is an invalid uplink If the grant indication is given to the subframe, then the HARQ operation is not performed on the subframe, and no indication is sent to the HARQ process corresponding to the subframe.