CN107294679B

CN107294679B - Feedback method and device for downlink transmission of downlink short TTI (transmission time interval)

Info

Publication number: CN107294679B
Application number: CN201610200910.3A
Authority: CN
Inventors: 邓云
Original assignee: Spreadtrum Communications Shanghai Co Ltd
Current assignee: Spreadtrum Communications Shanghai Co Ltd
Priority date: 2016-03-31
Filing date: 2016-03-31
Publication date: 2020-04-28
Anticipated expiration: 2036-03-31
Also published as: CN107294679A

Abstract

A feedback method and device for downlink transmission of downlink short TTI (transmission time interval), wherein the feedback method for downlink transmission of downlink short TTI comprises the following steps: for user equipment adopting downlink short TTI, determining a plurality of different reference values according to different scheduling initial positions of the user equipment in the same subframe; at least a part of the reference values are sent to the user equipment, so that the user equipment determines the resource position for sending HARQ feedback according to the reference values. The technical scheme of the invention realizes the determination of the resource position fed back by the HARQ when the downlink short TTI exists, and avoids the resource conflict when the HARQ feedback is sent.

Description

Feedback method and device for downlink transmission of downlink short TTI (transmission time interval)

Technical Field

The present invention relates to the field of wireless communications technologies, and in particular, to a feedback method and apparatus for downlink transmission of a downlink short TTI.

Background

In the conventional Long Term Evolution (LTE), a base station (eNB) schedules transmission of Downlink data and transmission of uplink data through Downlink Control Information (DCI) in a subframe.

In the prior art, when a base station transmits downlink data, a UE determines a position of a feedback resource according to a minimum Control Channel Element (CCE) index and a fixed reference value that constitute DCI. For downlink data transmission, the base station indicates, through DCI, resource configuration for downlink data transmission, for example, a modulation and coding format, location information of an allocated physical resource block, and the like, to a User Equipment (UE) in a subframe n. The base station performs user scheduling once per transmission time-interval (TTI), and the downlink TTI is defined as 1ms (uplink TTI is also 1ms) and is the length of 1 subframe (subframe), that is, the base station performs user scheduling once every 1 ms. The UE resolves its DCI, for example, the DCI scrambled with its Radio Network Temporary Identity (RNTI), and receives data on a physical downlink shared channel according to resource configuration information included in the DCI. If the UE can correctly decode the data, the UE sends an Acknowledgement (ACK) in a subframe (for Frequency Division Duplex (FDD), subframe n + 4; for Time Division Duplex (TDD), subframe n + k, k > -4) after the UE; if the UE cannot solve the data, the UE needs to feed back a Negative Acknowledgement Character (NACK). Generally, a UE performs Hybrid Automatic Repeat Request (HARQ) feedback, such as ACK or NACK feedback, on a Physical Uplink Control Channel (PUCCH) to a base station. To reduce transmission delay, a short transmission time interval sTTI will be introduced in LTE, which is typically shorter than the conventional 1ms, e.g. the sTTI may be 2, 4 or 7 Orthogonal Frequency Division Multiplexing (OFDM) symbols (symbols).

However, after the LTE introduces a shorter downlink transmission time interval sTTI, a scheduling manner of TTI 1ms and a scheduling manner of short transmission time interval sTTI exist in a cell at the same time, and the prior art can only schedule for UE using TTI 1 ms; and the UE adopting TTI of 1ms will occupy a part of PUCCH resources when feeding back ACK or NACK, if a part of UE adopts short transmission time interval sTTI scheduling at the moment, the feedback resources among the UE adopting multi-TTI scheduling will generate conflict, and the prior art can not solve the problem.

Disclosure of Invention

The technical problem solved by the invention is how to determine the resource position fed back by the HARQ when the downlink short TTI exists so as to avoid resource conflict when the HARQ feedback is sent.

In order to solve the above technical problem, an embodiment of the present invention provides a feedback method for downlink transmission of a downlink short TTI, where the feedback method for downlink transmission of the downlink short TTI includes: for user equipment adopting downlink short TTI, determining a plurality of different reference values according to different scheduling initial positions of the user equipment in the same subframe; and respectively sending the plurality of reference values to the user equipment so that the user equipment determines the resource position for sending HARQ feedback according to the reference values.

Optionally, determining a plurality of different reference values according to different scheduling starting positions of the ue in the same subframe includes: determining different reference values for different scheduling starting positions; the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

Optionally, determining a plurality of different reference values according to different scheduling starting positions of the ue in the same subframe includes: determining the same reference value and a plurality of different offsets for different scheduling starting positions; the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

Optionally, for different scheduling start positions, determining a plurality of different offsets includes: setting the corresponding offset of the first scheduling starting position to be 0; for each subsequent scheduling starting position, determining at least one downlink short TTI corresponding to at least one scheduling starting position before the current scheduling starting position, calculating the ratio of the available resource size of each downlink short TTI to the resource size occupied by the downlink control information, and adding at least one ratio to be used as the offset corresponding to the current scheduling starting position.

Optionally, the multiple reference values are set, so that the resource positions of the ue and other ues for sending HARQ feedback are staggered in the same subframe.

Optionally, the resource location where the ue sends the HARQ feedback is located in a physical uplink control channel with an uplink TTI of 1ms or a physical uplink control channel with an uplink short TTI.

Optionally, before the ue sends the HARQ feedback on the physical uplink control channel of the uplink short TTI, the ue receives the length information of the uplink short TTI.

Optionally, the length of the downlink short TTI includes at least one of: a length of 2 symbols, a length of 3 symbols, a length of 4 symbols, and a length of 7 symbols.

In order to solve the above technical problem, an embodiment of the present invention further discloses a feedback device for downlink transmission of a downlink short TTI, where the feedback device for downlink transmission of the downlink short TTI includes:

a reference value determining unit, adapted to determine, for a user equipment employing a downlink short TTI, a plurality of different reference values according to different scheduling starting positions of the user equipment within the same subframe; a feedback position calculation unit, adapted to send at least a part of the plurality of reference values to the user equipment, so that the user equipment determines, according to the reference values, a resource position for sending HARQ feedback.

Optionally, the reference value determining unit includes: a reference value determining subunit adapted to determine different reference values for different ones of the scheduling start positions; and the feedback position calculation unit adds the reference value and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

Optionally, the reference value determining unit includes: an offset determining subunit adapted to determine, for different ones of the scheduling start positions, a same reference value and a plurality of different offsets; and the feedback position calculation unit adds the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

Optionally, the offset determining subunit includes: the offset calculation submodule sets the corresponding offset of the first scheduling starting position to be 0; for each subsequent scheduling starting position, determining at least one downlink short TTI corresponding to at least one scheduling starting position before the current scheduling starting position, calculating the ratio of the available resource size of each downlink short TTI to the resource size occupied by the downlink control information, and adding at least one ratio to be used as the offset corresponding to the current scheduling starting position.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:

in this embodiment, for a ue using a downlink short TTI, a plurality of different reference values are determined according to different scheduling start positions of the ue in the same subframe; at least a part of the reference values are sent to the user equipment, so that the user equipment determines the resource position for sending HARQ feedback according to the reference values. Different reference values are determined through different scheduling starting positions, and different HARQ feedback resource positions are obtained based on the different reference values, so that the HARQ feedback resource positions are determined when the downlink short TTI exists, and meanwhile, the conflict of the HARQ feedback resource positions between the user equipment adopting the downlink short TTI is avoided, and the user equipment and the base station can continuously communicate.

Further, different reference values are determined for different scheduling starting positions; and adding the reference value and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback. By determining different reference values according to different scheduling starting positions and obtaining different HARQ feedback resource positions based on the different reference values and the minimum index of the control channel element in the downlink control information, the determination of the HARQ feedback resource positions in the presence of the downlink short TTI is realized, and meanwhile, the conflict of the HARQ feedback resource positions of the user equipment adopting the downlink short TTI is avoided.

Further, the same reference value and a plurality of different offsets are determined for different scheduling starting positions; and adding the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback. By determining different offsets according to different scheduling starting positions and obtaining different HARQ feedback resource positions based on the different offsets, the same reference value and the minimum index of the control channel element in the downlink control information, the determination of the HARQ feedback resource positions in the presence of the downlink short TTI is realized.

Drawings

Fig. 1 is a flowchart of a feedback method of downlink transmission of a downlink short TTI according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a time domain corresponding relationship of a feedback method of downlink transmission of a downlink short TTI according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a feedback apparatus for downlink transmission of a downlink short TTI according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another feedback apparatus for downlink transmission of downlink short TTI according to an embodiment of the present invention.

Detailed Description

As described in the background art, after the LTE introduces a shorter TTI, a scheduling mode with 1ms TTI and a scheduling mode with short TTI exist in a cell at the same time, and the prior art can only schedule UEs with 1ms TTI; and the UE adopting TTI of 1ms will occupy a part of PUCCH resources when feeding back ACK or NACK, if a part of UE adopts short transmission time interval sTTI scheduling at the moment, the feedback resources among the UE adopting multi-TTI scheduling will generate conflict, and the prior art can not solve the problem.

The downlink short TTI referred to in the embodiments of the present invention may be a short transmission time interval sTTI (marked by sTTI for distinguishing from a conventional TTI) with a time length of less than 1 ms.

The feedback method and the device for downlink transmission of the downlink short TTI can be used for a base station and can be used in a Long Term Evolution (LTE) communication system.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 1 is a flowchart of a feedback method of downlink transmission of a downlink short TTI according to an embodiment of the present invention. A detailed description will be given below to a specific embodiment of the feedback method for downlink transmission of downlink short TTI with reference to fig. 1.

Step S101: and for the user equipment adopting the downlink short TTI, determining a plurality of different reference values according to different scheduling initial positions of the user equipment in the same subframe.

For the purpose of distinction, in this embodiment, for a UE scheduled by TTI of 1ms, a base station sends Downlink Control Information (DCI) to a User Equipment (UE) through a Physical Downlink Control Channel (PDCCH) to implement scheduling of the UE; for user equipments scheduled with a TTI less than 1ms, the base station schedules the user equipment by shortening the shortened dci (sddci) on the pdcch (spdcch). The scheduling start position may be a resource position corresponding to a PDCCH or an sPDCCH in a single subframe (subframe), or may be a resource position corresponding to a minimum index of a Control Channel Element (CCE) or a shortened CCE in downlink control information in the same subframe. The DCI consists of one or more CCEs, and each CCE has an index; accordingly, the sDCI consists of one or more scces, each sCCE having an index.

It should be noted that the "subframe" herein has the same time length as the subframe in LTE in the related art, i.e. 1 ms. For a normal Cyclic Prefix (CP), 1ms contains 14 symbols.

In a specific implementation, the length of the downlink short TTI includes at least one of: at least one of a length of 2 symbols, a length of 3 symbols, a length of 4 symbols, and a length of 7 symbols.

In specific implementation, in order to avoid resource collision when the UE scheduled by using the downlink short TTIs with different lengths feeds back, a plurality of different reference values are determined according to different scheduling start positions of the UE in the same subframe (i.e., different start positions of the sTTI in the subframe). Here, it is not limited to different UEs scheduled in the subframe, and Hybrid Automatic Repeat Request (HARQ) feedback will be sent to the base station through a Physical Uplink Control Channel (PUCCH) in the same subframe after the subframe is scheduled. For example, for Frequency Division Duplex (FDD), a UE scheduled by DCI transmits HARQ feedback in the 4 th subframe after the subframe is scheduled; for Time Division Duplex (TDD), HARQ feedback is sent in the kth subframe after the scheduled subframe, where k > is 4, and for a UE scheduled by dci, HARQ feedback may be sent in the 4 th subframe after the scheduled subframe, or in order to further shorten the Time delay, the UE is allowed to send HARQ feedback in the 2 nd or 3 rd subframe after the scheduled subframe. In this case, resource locations where multiple UEs transmit HARQ feedback may collide, because for a UE scheduled by sDCI, regardless of which subframe it feeds back, it is necessary to avoid using the same PUCCH resource as the UE scheduled by DCI.

It should be noted here that the UE only needs to feed back ACK/NACK when receiving data according to DCI or sDCI after receiving its DCI or sDCI, and this patent is only directed to this scenario; if the UE does not need to receive data after receiving its DCI or sDCI, ACK/NACK does not need to be fed back, which is not addressed in this patent.

In a specific implementation, the plurality of reference values may be a plurality of different reference values, or may be a plurality of different offsets and the same reference value. Specifically, the reference value may be a parameter set by the base station for the UE to calculate a resource location for transmitting HARQ (i.e. a PUCCH resource location), and the base station may indicate the reference value to the UE in a system message, for example, for a UE scheduled by DCI, the base station indicates the reference value to such UE through the system message; for the UE scheduled by the sDCI, the base station needs to notify the UE of the reference value through a dedicated signaling, such as a Radio Resource Control (RRC) signaling. For UE adopting DCI scheduling, the existing mechanism is adopted to determine the resource position of HARQ feedback, and the method mainly aims at how the UE adopting sDCI scheduling determines the resource position (namely PUCCH resource position) of HARQ feedback.

In this embodiment, the positions of the resources for the ue and other ues to send HARQ feedback are staggered in the same subframe by setting the multiple reference values. The specific setting mode is not limited, and it is subject to that the resource positions for transmitting the HARQ feedback by the user equipment and the other user equipments are staggered in the same subframe.

It should be noted that the number of the user equipment using the downlink short TTI may be one or multiple, and the reference value determining manner may refer to the above corresponding embodiments, which is not limited in this embodiment of the present invention.

Step S102: at least a part of the reference values are sent to the user equipment, so that the user equipment determines the resource position for sending HARQ feedback according to the reference values.

After obtaining the plurality of reference values in step S101, at least a part of the plurality of reference values is sent to the ue, so that the ue determines the resource location for sending HARQ feedback according to the reference values. The user equipment and the scheduling starting position of the user equipment in the same subframe and the reference value form a corresponding relation. Specifically, for a UE scheduled by dci, the base station needs to notify the UE of the reference value through dedicated signaling, for example, Radio Resource Control (RRC) signaling; if a plurality of sTTI are included in one subframe (the starting position of each sTTI is different), the base station may inform one reference value, or set different reference values for different sTTI and inform the UE of the different reference values through RRC signaling.

In a specific implementation, after the plurality of reference values are obtained in step S101, since the UE may only perform scheduling in a part of sTTI, the reference value corresponding to the part of sTTI where the UE performs scheduling is notified to the UE; and for the reference value corresponding to the rest part of sTTI, the UE is not notified any more.

In a specific implementation, the determination of the resource location for sending the HARQ feedback (PUCCH resource location, where the time length of the existing PUCCH is 1 ms; if the UE can send the HARQ feedback through a physical uplink control channel less than 1ms, it is called sPUCCH, and is also referred to as sPUCCH resource location herein) may be obtained by adding a plurality of reference values to the minimum index of sCCE in the dci of the UE itself. The resource position for sending the HARQ feedback may be a subframe after the subframe where the UE receives the data or a period of time in the subframe, and the subframe where the UE receives the data has a fixed timing offset from the subframe where the HARQ feedback is sent. Wherein, the HARQ feedback may be an Acknowledgement Character (ACK) and a Negative Acknowledgement Character (NACK). For example, if the UE can correctly resolve the received data, an ACK is sent; otherwise, NACK is sent.

Specifically, the sddci is composed of one or more scces, for example, a specific number of the scces may be all or part of 1, 2, 4, or 8, and the like, the number is referred to as an aggregation level, and different aggregation levels may correspond to scheduling of UEs in different channel environments; when the aggregation level of the sDCI is 1, the sDCI is composed of 1 sCCE, and an index of the sCCE may be used to determine a resource location for transmitting HARQ; when the aggregation level of the sdic is 4, for example, the sdic is composed of sCCE4, sCCE5, sCCE6, and sCCE7, the index of sCCE4 may be used to determine the resource location for transmitting HARQ, and the minimum index of sCCE at other aggregation levels may be obtained by the same way.

In specific implementation, different reference values are determined for different scheduling starting positions; the determining, by the user equipment, a resource location (PUCCH or sPUCCH resource location) for sending HARQ feedback according to the reference value includes: and adding the reference value and the minimum index of a control channel element (sCCE) in downlink control information (sDCI) received by the user equipment to obtain a resource position for sending the HARQ feedback. Or, the ue determines the resource location for sending the HARQ feedback directly according to the reference value.

Specifically, when the uplink TTI of multiple UEs is 1ms, the UE using the short transmission time interval sTTI receives the corresponding downlink control information sdic and the corresponding data in the subframe n, and after the UE decodes the downlink control information sdic and the corresponding data, the UE needs to send HARQ feedback in a subframe with a fixed timing, such as n +3 or n + 4. T is used because of the simultaneous need to feed back UEs scheduled using a regular TTI (i.e., TTI of 1ms) in subframe n +3 or n +4The UE scheduled by TI may also occupy PUCCH Resource to send HARQ feedback, and the UE scheduled by sTTI (for example, TTI is less than 1ms, and marked by sTTI for distinguishing from regular TTI) needs to avoid using PUCCH Resource already occupied by UE with TTI of 1ms, so the base station may additionally indicate the reference value to the UE scheduled by sTTI through Radio Resource Control (RRC) signaling

Accordingly, the resource location of the PUCCH for transmitting the HARQ feedback may be determined by using the following expression:

wherein the content of the first and second substances,

indicates the position of the PUCCH resource that sends HARQ feedback at antenna port p0, n_sCCEAnd the minimum index of the sCCE contained in the sDCI of the UE is represented. In the same subframe, the UE adopting different TTI scheduling can feed back ACK/NACK in the same subframe, and can also feed back ACK/NACK in different subframes. If the subframe n contains a plurality of sTTIs, that is, symbols used by different sTTIs are different, the base station can instruct the UE to apply different reference values to different sTTIs, and when the UE calculates the fed-back PUCCH resource, the UE adopts a corresponding reference value according to the position of the sTTI where the sDCI is located, and at this time, the reference value only contains the reference value; or the base station may indicate a general reference value, and the UE needs to use the reference value and an additional offset when calculating the fed-back PUCCH resource, where the offset may be configured by the base station or calculated by the UE, and the reference value includes the reference value and the offset.

It can be understood that, if the UE employs two antenna port transmission, the expression of the PUCCH resource for the UE to send the HARQ feedback at antenna port p1 is:

wherein the content of the first and second substances,

indicates the position of the PUCCH resource that sends HARQ feedback at antenna port p1, n_sCCEAnd the minimum index of the sCCE contained in the sDCI is represented. When multiple antenna ports are used for transmission, the expression of the PUCCH resource for sending the HARQ feedback may be analogized, which is not limited in the embodiment of the present invention.

Specifically, referring to fig. 2, fig. 2 is a schematic time domain diagram of a feedback method of downlink transmission of a downlink short TTI according to an embodiment of the present invention. A base station performs Downlink DL (Downlink DL) scheduling for multiple UEs, such as UE1, UE2, … …, and UE100, wherein the base station performs scheduling for some UEs using a conventional TTI (that is, a TTI is 1ms), and some UEs use an sTTI. A Physical Downlink Control Channel (PDCCH) corresponding to the conventional TTI may occupy the first 1 to 3 symbols of the subframe. For example, for subframe n, the subframe time length is 1ms, which includes two slots (i.e., slot 0 and slot 1), each of which includes 7 symbols. When the PDCCH occupies the first 3 symbols, the first slot of the subframe has 4 more symbols available for sTTI and the second slot has 7 symbols available for sTTI. The base station may configure some UEs to use 4 symbols for sTTI in the first slot and some UEs to use 7 symbols for sTTI in the second slot. For the UE adopting sTTI scheduling, the UE needs to feed back ACK/NACK, and the UE needs to send feedback on a subframe (i.e. PUCCH) or a partial symbol (i.e. sPUCCH) of the subframe after the subframe where data is received.

For example, in one non-limiting example, UE2 is scheduled with 4 symbols in slot 0 and UE3 is scheduled with 7 symbols in slot 1. In order to avoid PUCCH resource collision when the UE2 and the UE3 send HARQ feedback, different reference values may be configured for the UE2 and the UE3 according to the scheduling start position, and the base station may configure the reference value of the UE2 to be the UE2 and the UE3 through RRC signaling

The reference value of PUCCH configuring UE3 is

Then UE2, upon detecting its dci and corresponding data transmission within the first sTTI (e.g., sTTI starting from 4 th symbol in slot 0), UE2 employs PUCCH resource for transmitting HARQ feedback in calculating PUCCH resource

When UE3 detects its DCI (downlink control information in sTTI, marked with DCI for distinguishing from regular DCI) and corresponding data transmission in a second sTTI (e.g., sTTI with length slot 1), UE3 adopts in calculating the HARQ feedback PUCCH resource

The corresponding relationship between the resource position for sending HARQ feedback and the scheduling start position is shown as curve 1 and curve 2, where curve 1 represents Uplink (UL) HARQ feedback for the first sTTI; curve 2 represents the uplink HARQ feedback for the second sTTI. Similarly, if UE2 detects its sddci and corresponding data transmission in the second sTTI (sTTI with length of 7 symbols and located in slot 1), UE2 adopts the HARQ feedback PUCCH resource calculation

The corresponding relationship between the resource location for sending HARQ feedback and the scheduling start location is shown in curve 2. The base station may schedule the UE2 in the first sTTI or the second sTTI, so the base station needs to notify the UE of different reference values corresponding to the two sTTI, and the UE determines which reference value to use to determine the PUCCH resource fed back by the HARQ according to the sTTI where the UE is scheduled.

In a specific implementation, the same reference value and a plurality of different offsets may also be used for different scheduling start positions; the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value, the offset and the minimum index of a control channel element (sCCE) in downlink control information (sDCI) received by the user equipment to obtain a resource position for sending the HARQ feedback.

Specifically, for multiple UEs scheduled by using different sttis, the base station may configure the same reference value, and set different offset offsets for UEs at different scheduling start positions in the subframe, for example, for UE2, if the base station schedules UE2 in the first sTTI (e.g., the sTTI starting from the 4 th symbol in slot 0), UE2 uses the reference value when calculating PUCCH resources

If the base station schedules UE2 in the second sTTI (e.g., sTTI within slot 1, which may be 7 symbols in length), UE2 calculates the PUCCH resources using

And an offset.

In specific implementations, the offset may be configured by the base station through RRC signaling or obtained by the UE through calculation. The offset may be calculated by: for a first scheduling start position (i.e. the start position corresponding to the first sTTI), setting the offset corresponding to the first scheduling start position to 0; for each subsequent scheduling start position (for example, for the start position corresponding to the second sTTI located in the time slot 1), determining the number of sTTI included before the current scheduling start position in the subframe, calculating the offset corresponding to each sTTI, and summing the offsets to obtain the offset corresponding to the current scheduling start position.

For example, in one non-limiting example, UE1 employs conventional TTI (i.e., TTI of 1ms) scheduling, and more specifically, UE1 is scheduled via a conventional PDCCH occupying 3 symbols in length within the same subframe; if the UE2 is scheduled within the first sTTI after the PDCCH (e.g., the sTTI in slot 0 starting from the 4 th symbol to the 7 th symbol), then the offset is 0; if UE2 is scheduled in the second sTTI (e.g., an sTTI with a length of 7 symbols and located in slot 1) after the PDCCH, UE2 needs to calculate an offset corresponding to the first sTTI, and specifically, UE2 determines an offset value according to a resource size available for configuring sPDCCH (i.e., a physical downlink control channel corresponding to the sTTI and marked with sPDCCH for distinguishing from a conventional PDCCH) in the first sTTI and a resource size occupied by sdic in the sPDCCH (i.e., downlink control information included in the sPDCCH), which may generally be determined according to a ratio of the two and by rounding up. For example, if there are 6 Physical Resource Blocks (PRBs) in the first sTTI that can be configured as the sPDCCH, there are 6 × 4 × 12 ═ 288 REs (Resource elements), where part of the REs are to be occupied by transmitting cell-specific reference signals, and therefore less than 288 REs available for the sPDCCH, where 288 × 0.75 ═ 216 REs are assumed to be available for transmitting the sPDCCH, and if one dci occupies 36 REs at minimum, the offset is 216/36 ═ 6, and then the offset is 6.

It will be appreciated that the determination of the specific offset needs to be calculated and adjusted according to the actual application environment. From the above, the parameters affecting the offset may be one or more of the following: the resource size of the physical downlink control channel, the resource size occupied by the reference signal, the number of antenna ports and the resource size occupied by the downlink control information can be configured. When a subframe includes multiple sTTI, such as 4 sTTI, and the UE is scheduled in the 4 th sTTI, the UE needs to calculate offset offsets corresponding to the first three sTTI, sum the offset offsets corresponding to the three sTTI, so as to use the offset offsets for the UE to determine HARQ feedback.

In this embodiment, when the uplink TTI is 1ms, the resource locations where the ue and other ues send HARQ feedback are different in the same subframe.

In a specific implementation, when the uplink TTI is 0.5ms (that is, the UE feeds back on the shortened PUCCH), the resource positions of the UE and the other UEs transmitting the HARQ feedback are different in the same timeslot. At this time, the base station needs to indicate the length of TTI used for UE feedback in advance, for example, the base station notifies the UE through RRC signaling. Specifically, the UE receives data in subframe n, and the UE transmits HARQ feedback on a subframe after the subframe in which the data is received. When the uplink TTI is 0.5ms, the UE may send HARQ feedback in subframe n +3 or subframe n +2 in order to shorten the feedback delay. For example, the UE sends HARQ feedback in subframe n + 3. If the base station schedules UE2 in the first sTTI of subframe n (e.g., sTTI starting from 4 th symbol in slot 0), UE2 needs to send HARQ feedback in the first slot of subframe n + 3; if the base station schedules UE2 in the second sTTI of subframe n (e.g., the sTTI with the second slot length of 7 symbols), UE2 needs to send HARQ feedback in the second slot of subframe n + 3. The base station may configure different reference values for different feedback slot positions based on the scheduling start position (symbol 4 of slot 0 and symbol 1 of slot 1), and then the UE calculates the sPUCCH resource position occupied by sending the HARQ feedback according to the reference value and the minimum sCCE of the dci.

It can be understood that, when the uplink TTI is 0.5ms, the same reference value and a plurality of different offsets may also be determined for different scheduling start positions; the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value, the offset and the minimum index of a control channel element (sCCE) in downlink control information (sDCI) received by the user equipment to obtain a resource position for sending the HARQ feedback. The resource positions of different user equipments sending HARQ feedback may be different or the same in the corresponding time slots in the same subframe; if the HARQ feedback is sent in the same time slot, different HARQ feedback resources are needed.

In a specific implementation, when the uplink TTI is less than 0.5ms, the resource location where the ue sends the HARQ feedback is on a part of symbols in a subframe, and the resource locations where the ue and other ues send the HARQ feedback need to be staggered on the symbols. Specifically, for a ue using a downlink short TTI, a plurality of different reference values are determined according to different scheduling start positions of the ue in the same subframe (i.e., different start positions of sTTI), where the plurality of reference values may be a plurality of reference values, or may be a plurality of offsets and the same reference value. The resource positions of the user equipment and other user equipment for sending the HARQ feedback are staggered on the symbol in the same subframe.

The embodiment of the invention determines different reference values through different scheduling starting positions, and obtains different resource positions fed back by the HARQ based on the different reference values and the minimum index of the control channel element (sCCE) in the downlink control information (sDCI), thereby realizing the determination of the resource positions fed back by the HARQ when the downlink short TTI with different lengths is scheduled, and simultaneously avoiding the conflict of the resource positions fed back by the HARQ sent by the user equipment scheduled by the downlink short TTI.

Fig. 3 is a schematic structural diagram of a feedback apparatus for downlink transmission of a downlink short TTI according to an embodiment of the present invention. A detailed description will be given below of a specific embodiment of the feedback apparatus for downlink transmission of downlink short TTI with reference to fig. 3.

The feedback device of downlink transmission comprises: a reference value determination unit 301 and a feedback position calculation unit 302.

The reference value determining unit 301 is adapted to determine, for a user equipment employing a downlink short TTI, a plurality of different reference values according to different scheduling starting positions of the user equipment within the same subframe; the feedback position calculation unit 302 is adapted to send at least a part of the plurality of reference values to the user equipment, so that the user equipment determines the resource position for sending HARQ feedback according to the reference values.

In a specific implementation, the plurality of reference values may be a plurality of reference values, or may be a plurality of offsets and the same reference value. Specifically, the reference value may be a parameter set by the base station for the UE to calculate the resource location for transmitting HARQ, and the base station indicates the reference value in RRC signaling. Determining different reference values for different scheduling starting positions; the feedback position calculating unit 302 adds the reference value and the minimum index of the control channel element in the downlink control information received by the ue to obtain the resource position for sending the HARQ feedback. Determining the same reference value and a plurality of different offsets for different scheduling starting positions; the feedback position calculation unit 302 adds the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the ue to obtain the resource position for sending the HARQ feedback.

It will be appreciated that the determination of the specific offset needs to be calculated and adjusted according to the actual application environment. From the above, the parameters affecting the offset may be one or more of the following: the resource size of the physical downlink control channel, the resource size occupied by the reference signal, the number of antenna ports and the resource size occupied by the downlink control information are configured.

The detailed description of the embodiments of the present invention may refer to the corresponding embodiments described above, and will not be repeated herein.

Fig. 4 is a schematic structural diagram of another feedback apparatus for downlink transmission of downlink short TTI according to an embodiment of the present invention. A detailed description will be given below of a specific embodiment of the feedback apparatus for downlink transmission of downlink short TTI with reference to fig. 4.

The feedback device of downlink transmission comprises: a reference value determination unit 301 and a feedback position calculation unit 302. Wherein the reference value determining unit 301 includes a reference value determining subunit 401 and an offset determining subunit 403; the offset determination subunit 403 includes an offset calculation submodule 402.

In a specific implementation, the length of the downlink short TTI includes at least one of: a length of 2 symbols, a length of 3 symbols, a length of 4 symbols, and a length of 7 symbols.

In a specific implementation, the reference value determining subunit 401 is adapted to determine different reference values for different scheduling start positions; the feedback position calculating unit 302 adds the reference value and the minimum index of the control channel element in the downlink control information received by the ue to obtain the resource position for sending the HARQ feedback.

In a specific implementation, the offset determining subunit 403 is adapted to determine the same reference value and a plurality of different offsets for different scheduling start positions; the feedback position calculating unit 302 adds the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the ue to obtain the resource position for sending the HARQ feedback.

In specific implementation, the offset calculation sub-module 402 sets the offset corresponding to the first scheduling start position to 0; for each subsequent scheduling starting position, determining at least one downlink short TTI corresponding to at least one scheduling starting position before the current scheduling starting position, calculating the ratio of the available resource size of each downlink short TTI to the resource size occupied by the downlink control information, and adding at least one ratio to be used as the offset corresponding to the current scheduling starting position.

In the embodiment of the invention, the plurality of reference values are set, so that the resource positions of the user equipment and other user equipment for sending the HARQ feedback are staggered in the same subframe.

Specifically, the resource position where the user equipment sends the HARQ feedback is on the physical uplink control channel with uplink TTI of 1ms or the physical uplink control channel with uplink short TTI; and before the user equipment sends the HARQ feedback on the physical uplink control channel of the uplink short TTI, the user equipment receives the length information of the uplink short TTI.

Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer-readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, and the like.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A feedback method for downlink transmission of a downlink short Transmission Time Interval (TTI) is characterized by comprising the following steps:

for user equipment adopting downlink short TTI, determining a plurality of different reference values according to different scheduling initial positions of the user equipment in the same subframe, so that the resource positions of the user equipment and other user equipment for sending HARQ (hybrid automatic repeat request) feedback are staggered in the same subframe;

at least a part of the reference values are sent to the user equipment, so that the user equipment determines the resource position for sending HARQ feedback according to the reference values.

2. The feedback method of downlink transmission of downlink short TTI according to claim 1, wherein determining a plurality of different reference values according to different scheduling start positions of the ue in the same subframe comprises: determining different reference values for different scheduling starting positions;

the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

3. The feedback method of downlink transmission of downlink short TTI according to claim 1, wherein determining a plurality of different reference values according to different scheduling start positions of the ue in the same subframe comprises: determining the same reference value and a plurality of different offsets for different scheduling starting positions;

the determining, by the user equipment according to the reference value, a resource location for sending HARQ feedback includes: and adding the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

4. The feedback method of downlink transmission of downlink short TTI according to claim 3, wherein determining a plurality of different offsets for different scheduling start positions comprises: setting the corresponding offset of the first scheduling starting position to be 0; for each subsequent scheduling starting position, determining at least one downlink short TTI corresponding to at least one scheduling starting position before the current scheduling starting position, calculating the ratio of the available resource size of each downlink short TTI to the resource size occupied by the downlink control information, and adding at least one ratio to be used as the offset corresponding to the current scheduling starting position.

5. The feedback method of downlink transmission of downlink short TTI according to claim 1, wherein the resource location for the ue to send HARQ feedback is in the physical uplink control channel of uplink short TTI or the physical uplink control channel of uplink short TTI with 1 ms.

6. The feedback method for downlink transmission in downlink short TTI according to claim 5, wherein, before the UE sends the HARQ feedback on the physical uplink control channel in uplink short TTI, the UE receives the length information of uplink short TTI.

7. The feedback method for downlink transmission of downlink short TTI according to any one of claims 1 to 6, wherein the length of the downlink short TTI comprises at least one of the following: a length of 2 symbols, a length of 3 symbols, a length of 4 symbols, and a length of 7 symbols.

8. A feedback apparatus for downlink transmission of a downlink short TTI, comprising:

a reference value determining unit, adapted to determine, for a user equipment using a downlink short TTI, a plurality of different reference values according to different scheduling starting positions of the user equipment in the same subframe, so that resource positions where the user equipment and other user equipments send HARQ feedback are staggered in the same subframe;

a feedback position calculation unit, adapted to send at least a part of the plurality of reference values to the user equipment, so that the user equipment determines, according to the reference values, a resource position for sending HARQ feedback.

9. The feedback apparatus of downlink transmission of downlink short TTI according to claim 8, wherein the reference value determining unit comprises:

a reference value determining subunit adapted to determine different reference values for different ones of the scheduling start positions;

and the feedback position calculation unit adds the reference value and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

10. The feedback apparatus of downlink transmission of downlink short TTI according to claim 8, wherein the reference value determining unit comprises:

an offset determining subunit adapted to determine, for different ones of the scheduling start positions, a same reference value and a plurality of different offsets;

and the feedback position calculation unit adds the reference value, the offset and the minimum index of the control channel element in the downlink control information received by the user equipment to obtain the resource position for sending the HARQ feedback.

11. The feedback apparatus for downlink transmission of downlink short TTI according to claim 10, wherein the offset determining subunit comprises:

the offset calculation submodule sets the corresponding offset of the first scheduling starting position to be 0; for each subsequent scheduling starting position, determining at least one downlink short TTI corresponding to at least one scheduling starting position before the current scheduling starting position, calculating the ratio of the available resource size of each downlink short TTI to the resource size occupied by the downlink control information, and adding at least one ratio to be used as the offset corresponding to the current scheduling starting position.

12. The apparatus as claimed in claim 8, wherein the resource location for the ue to send HARQ feedback is in the physical uplink control channel of uplink short TTI or the physical uplink control channel of uplink short TTI, where the uplink TTI is 1 ms.

13. The apparatus of claim 12, wherein the user equipment receives the length information of the uplink short TTI before the user equipment transmits the HARQ feedback on the physical uplink control channel of the uplink short TTI.

14. The feedback apparatus of downlink transmission of downlink short TTI according to any of claims 8 to 13, wherein the length of the downlink short TTI comprises at least one of: a length of 2 symbols, a length of 3 symbols, a length of 4 symbols, and a length of 7 symbols.