WO2013172691A1

WO2013172691A1 - Method and apparatus for transmitting and receiving harq feedback of downlink data

Info

Publication number: WO2013172691A1
Application number: PCT/KR2013/004407
Authority: WO
Inventors: Zheng Zhao; Chengjun Sun; Yingyang Li
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2012-05-18
Filing date: 2013-05-20
Publication date: 2013-11-21
Anticipated expiration: 2014-11-18
Also published as: CN103427962A

Abstract

The present invention discloses a method and an apparatus for transmitting HARQ-ACK feedback of downlink data, including: in a traffic adaptive TDD system, when an actual uplink/downlink configuration of the system is changed dynamically, an uplink/downlink configuration followed by HARQ-ACK timing of a downlink subframe is changed accordingly. The present invention discloses a principle that HARQ-ACK timing of a downlink subframe is performed within a certain range of a configuration conversion point. According to the method provided by the present invention, HARQ-ACK of more downlink subframes is transmitted; thereby physical resources of downlink subframes are saved effectively.

Description

METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING HARQ FEEDBACK OF DOWNLINK DATA

The present invention relates to a radio communication technology field, and more particularly to a method and an apparatus for transmitting ACKnowledgment (ACK) and Negative ACKnowledgment (NACK) of a Physical Downlink Shared Channel (PDSCH) in a traffic adaptive Time Division Duplexing (TDD) system when a TDD uplink/downlink configuration of a Cell is dynamically changed with uplink/downlink traffic.

A Long Term Evolution (LTE) technology supports two duplexing means, which are Frequency Division Duplexing (FDD) and TDD.

Figure 1 is a schematic diagram illustrating a frame structure of a TDD system in LTE. The length of each radio frame is 10ms, and each radio frame is halved into two half-frames, the respective length of which is 5ms. Each half-frame includes eight time slots of which the respective length is 0.5ms and three special domains of which the respective length is 1ms. The three special domains respectively are Downlink Pilot Time Slot (DwPTS), Guard Period (GP) and Uplink Pilot Time Slot (UpPTS); each subframe consists of two consecutive time slots.

Transmission in a TDD system includes transmission from a base station to a User Equipment (UE) (which is referred to as downlink) and transmission from the UE to the base station (which is referred to as uplink).

Based on the frame structure shown in Figure 1, the uplink and downlink share 10 subframes within every 10ms, each subframe is either configured for the uplink or for the downlink, a subframe configured for the uplink is called an uplink subframe and a subframe configured for the downlink is called a downlink subframe. The TDD system supports seven uplink/downlink configurations, as shown in Table 1, D represents a downlink subframe, U represents an uplink subframe, and S represents a special subframe including the above-mentioned three special domains.

[Table 1]

To improve a user transfer rate, an advanced LTE technology is proposed. An advanced LTE TDD system has the same Hybrid Automatic Repeat Request (HARQ) transmission timing as LTE. A HARQ transmission timing relationship of downlink data in advanced LTE is hereinafter described.

HARQ ACKnowledgment (HARQ-ACK) information of a PDSCH may be transmitted in a Physical Uplink Shared Channel (PUSCH) or a Physical Uplink Control Channel (PUCCH). For a timing relationship from the PDSCH to the PUCCH/PUSCH, assuming that a UE transmits HARQ-ACK in a PUCCH/PUSCH of an uplink subframe n, the PUCCH/PUSCH indicates the HARQ-ACK of a PDSCH or Semi-Persistent Scheduling (SPS) release within a downlink subframe n-k. Values of k are defined in Table 2; K is a set of M elements, relates to a serial number of a subframe and an uplink/downlink configuration, and is called a Downlink Association Set. A timing relationship from PDSCH or SPS release to HARQ-ACK of the PDSCH or SPS release is hereinafter referred to as PDSCH HARQ timing.

[Table 2]

As a user's requirement for a data transmission rate is improved, in discussion of the advanced LTE, a traffic adaptive TDD technology is proposed, in which a current uplink/downlink configuration more accords with a ratio of uplink traffic and downlink traffic through dynamically adjusting a ratio of uplink subframes and downlink subframes, so that an uplink/downlink peak rate of the user and a system throughput are improved.

In present invention, a timing relationship from PDSCH or SPS release to HARQ-ACK of the PDSCH or SPS release is referred to as HARQ timing of downlink data. For HARQ timing of downlink data, in a traffic adaptive TDD system, according to differences of actual uplink/downlink configurations, a base station needs to inform a UE a downlink reference configuration, the UE determines a timing relationship between downlink data and HARQ of the downlink data according to the reference configuration. The reference configuration may be different from an actual configuration, or may also be different from a configuration followed by uplink data scheduling and synchronous HARQ timing of the uplink data. The present invention assumes that the UE ascertains that the system will change the downlink reference configuration after a frame boundary, and assumes that the UE ascertains which uplink/downlink configuration will be changed to; the frame boundary is called a downlink reference configuration conversion point.

Figure 2 is a schematic diagram illustrating a configuration conversion point.

As shown in Figure 2, letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. Dotted line 201 is a downlink reference configuration conversion point, and also is a boundary between two frames. A downlink reference configuration of a frame before dotted line 201 is configuration 2, and a downlink reference configuration of a frame after dotted line 201 is configuration 1. In accordance with assumptions of the present invention, a UE ascertains that the system will use configuration 1 after dotted line 201.

In a traffic adaptive TDD system, for a downlink subframe before a configuration conversion point, an uplink subframe carrying HARQ-ACK of the downlink subframe may be in a downlink reference configuration which is different from a downlink reference configuration of the downlink subframe, therefore it is necessary to specify a downlink reference configuration, and HARQ-ACK of a downlink subframe close to the uplink/downlink configuration conversion point is transmitted in accordance with timing of the downlink reference configuration.

Figure 3 is a schematic diagram illustrating a timing relationship for a subframe after a configuration conversion point transmitting HARQ-ACK information of a downlink subframe before the configuration conversion point.

As shown in Figure 3, letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. Dotted line 301 is a downlink reference configuration conversion point, and also is a boundary between two frames. A downlink reference configuration of a frame before dotted line 301 is configuration 1, and a downlink reference configuration of a frame after dotted line 301 is configuration 2. In accordance with assumptions of the present invention, a UE ascertains that the system will use configuration 2 after dotted line 301. Before the configuration conversion point, if according to a timing relationship of configuration 1, HARQ-ACK of downlink data in

subframes

302, 303 and 304 is respectively transmitted in

subframes

305, 305 and 306 which are after the configuration conversion point.

As can be seen from Figure 3, subframe 306 is a downlink subframe, and could not transmit HARQ-ACK of subframe 304, so that a time sequence from downlink data within subframe 304 to the HARQ-ACK of the downlink data could not follow the timing relationship of configuration 1, otherwise the UE has to abandon the corresponding downlink data within subframe 304 due to not finding the HARQ-ACK corresponding to subframe 304.

The present invention discloses, in a traffic adaptive TDD system, a timing relationship between PDSCH or SPS release and PUSCH/PUCCH bearing HARQ-ACK of the PDSCH or SPS release when a downlink subframe bearing downlink data and an uplink subframe bearing HARQ-ACK of the downlink data are in different downlink reference configurations.

The present invention provides a method and apparatus for transmitting HARQ feedback of downlink data in a traffic adaptive TDD system.

The present invention provides a method and apparatus for receiving HARQ feedback of downlink data in a traffic adaptive TDD system.

An aspect of the present invention is to provides a method for transmitting Hybrid Automatic Repeat Request (HARQ) feedback of downlink data. The method includes:

a. receiving, by a User Equipment (UE), downlink data and uplink/downlink configuration changing information of a system;

b. detecting the received downlink data, determining HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data, determining a configuration conversion point according to the uplink/downlink configuration changing information, and determining a downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point; and

c. transmitting the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to the downlink reference configuration.

Preferably, step c includes:

for an uplink subframe before the configuration conversion point or after a preconfigured downlink reference configuration conversion point, transmitting the HARQ-ACK corresponding to the downlink data according to a HARQ-ACK timing relationship corresponding to an current actual uplink/downlink configuration of the system; and

for an uplink subframe between the configuration conversion point and the downlink reference configuration conversion point, transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ-ACK timing relationship corresponding to the determined downlink reference configuration.

Preferably, the downlink reference configuration conversion point is between subframe n+3 and subframe n+4, and the configuration conversion point is between subframe n-1 and subframe n.

Preferably, the downlink reference configuration conversion point is between subframe n+8 and subframe n+9, and the configuration conversion point is between subframe n-1 and subframe n.

Preferably, the downlink reference configuration conversion point is between subframe n+4 and subframe n+5, and the configuration conversion point is between subframe n-1 and subframe n.

Preferably, corresponding to a combination of uplink/downlink configurations before and after the configuration conversion point, the downlink reference configuration conversion point is between subframe n+3 and subframe n+4, or between subframe n+8 and subframe n+9, or between subframe n+4 and subframe n+5, or between subframe n+2 and subframe n+3.

Preferably, the downlink reference configuration determined according to the actual uplink/downlink configurations before and after the configuration conversion point includes:

wherein 5x indicates uplink/downlink configuration 5 and that the downlink reference configuration conversion point is between subframe n+2 and subframe n+3, and 2x indicates uplink/downlink configuration 5 and that the downlink reference configuration conversion point is between subframe n+2 and subframe n+3.

Preferably, the downlink reference configuration is an actual uplink/downlink configuration of the system before the configuration conversion point.

Preferably, the downlink reference configuration is an actual uplink/downlink configuration of the system after the configuration conversion point.

Preferably, the temporary downlink reference configuration determined according to the actual uplink/downlink configurations before and after the configuration conversion point includes:

Preferably, step b further includes:

determining a downlink action interval of the downlink reference configuration according to a position of the configuration conversion point or the downlink reference configuration;

step c further includes:

for all downlink subframes within the downlink action interval, transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ timing relationship corresponding to the downlink reference configuration.

Preferably, the determining a downlink action interval of the downlink reference configuration according to a position of the configuration conversion point includes:

determining a starting point of the downlink action interval as subframe X of an adjacent frame before the current configuration conversion point, and determining an end point of the downlink action interval as subframe X-1 of an adjacent frame before a next configuration conversion point; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; or

determining the starting point of the downlink action interval as subframe X of the adjacent frame before the current configuration conversion point, and determining the end point of the downlink action interval as subframe X-1 of an adjacent frame after the current configuration conversion point; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; transmitting, for a downlink subframe outside the downlink action interval, the HARQ-ACK corresponding to the downlink data according to the current actual configuration of the system.

Preferably, the determining a downlink action interval of the downlink reference configuration according to the downlink reference configuration includes:

determining a starting point of the downlink action interval as subframe X of a former frame in every two adjacent frames, and determining an end point of the downlink action interval as subframe X-1 of a latter frame in the every two adjacent frames; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; or

determining the end point of the downlink action interval according to the downlink reference configuration and based on a table shown as follows:

and determining the starting point of the downlink action interval as a next subframe of an end point of a last downlink action interval determined according to Table 6; wherein a boundary between frame n and frame n+1 is a configuration conversion point, or frame n and frame n+1 are any two adjacent frames.

Preferably, the method includes:

receiving, by the UE, the uplink/downlink configuration changing information in a subframe closest to the configuration conversion point before transmitting HARQ-ACK corresponding to downlink data carried by a first downlink subframe within the downlink action interval.

Preferably, the method includes:

when X=2, 3 or 4, transmitting, by a base station, the uplink/downlink configuration changing information 4ms or 5ms ahead of the configuration conversion point; and

receiving, by the UE, the uplink/downlink configuration changing information 4ms or 5ms ahead of the configuration conversion point.

Preferably, the method includes:

transmitting, by a base station, the uplink/downlink configuration changing information 9ms or 10ms ahead of the configuration conversion point; and

receiving, by the UE, the uplink/downlink configuration changing information 9ms or 10ms ahead of the configuration conversion point.

Preferably, between step b and step c, the method further includes: determining an uplink action interval according to a way for determining the downlink action interval and a way for determining the downlink reference configuration;

wherein the transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ timing relationship corresponding to the downlink reference configuration for all downlink subframes within the downlink action interval comprises:

transmitting, by all uplink subframes within the uplink action interval, HARQ-ACK of downlink data carried by a downlink subframe corresponding to an uplink subframe within the uplink action interval according to the HARQ timing relationship corresponding to the downlink reference configuration.

Preferably, when the way for determining the downlink reference configuration is shown in a table as follows:

and the way for determining the downlink action interval is "determining a starting point of the downlink action interval as subframe X of an adjacent frame before the current configuration conversion point, and determining an end point of the downlink action interval as subframe X-1 of an adjacent frame before a next configuration conversion point; wherein X=2, 3 or 4", the determining an uplink action interval includes:

when the uplink/downlink configuration is not changed from configuration 0 to 6, and is not changed from configuration 0 to configuration 1, and is not changed from configuration 0 to configuration 2, and is not changed from configuration 6 to configuration 0, and is not changed from configuration 6 to configuration 1, and is not changed from configuration 6 to configuration 2, determining a starting point of the uplink action interval as subframe 8 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 7 of the adjacent frame before the next configuration conversion point;

when the uplink/downlink configuration is changed from configuration 0 to configuration 6, or is changed from configuration 0 to configuration 1, or is changed from configuration 0 to configuration 2, or is changed from configuration 6 to configuration 0, or is changed from configuration 6 to configuration 1, or is changed from configuration 6 to configuration 2, determining the starting point of the uplink action interval as subframe 9 of the adjacent frame before the current configuration conversion point, and determining the end point of the uplink action interval as subframe8 of the adjacent frame before the next configuration conversion point.

determining a starting point of the uplink action interval as subframe 8 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 7 of the adjacent frame before the next configuration conversion point; or

determining the starting point of the uplink action interval as subframe 9 of the adjacent frame before the current configuration conversion point, and determining the end point of the uplink action interval as subframe 8 of the adjacent frame before the next configuration conversion point; or

determining the starting point of the uplink action interval as subframe 0 of an adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 9 of the adjacent frame before the next configuration conversion point; or

determining the starting point of the uplink action interval as subframe 1 of the adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 0 of an adjacent frame after the next configuration conversion point; or

determining the starting point of the uplink action interval as subframe 2 of the adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 1 of the adjacent frame after the next configuration conversion point.

determining a starting point of the uplink action interval as subframe 8 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 7 of the adjacent frame before the next configuration conversion point.

and the way for determining the downlink action interval is "determining a starting point of the downlink action interval as subframe X of an adjacent frame before the current configuration conversion point, and determining an end point of the downlink action interval as subframe X-1 of an adjacent frame after the current configuration conversion point; wherein X=2, 3 or 4", or the way for determining the downlink action interval is "determining the starting point of the downlink action interval as subframe X of a former frame in every two adjacent frames, and determining the end point of the downlink action interval as subframe X-1 of a latter frame in the every two adjacent frames; wherein X=2, 3 or 4", the determining an uplink action interval includes:

when the uplink/downlink configuration is not changed from configuration 0 to 6, and is not changed from configuration 0 to configuration 1, and is not changed from configuration 0 to configuration 2, and is not changed from configuration 6 to configuration 0, and is not changed from configuration 6 to configuration 1, and is not changed from configuration 6 to configuration 2, determining a starting point of the uplink action interval as subframe 8 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 7 of the adjacent frame after the current configuration conversion point;

when the uplink/downlink configuration is changed from configuration 0 to configuration 6, or is changed from configuration 0 to configuration 1, or is changed from configuration 0 to configuration 2, or is changed from configuration 6 to configuration 0, or is changed from configuration 6 to configuration 1, or is changed from configuration 6 to configuration 2, determining the starting point of the uplink action interval as subframe 9 of the adjacent frame before the current configuration conversion point, and determining the end point of the uplink action interval as subframe8 of the adjacent frame after the current configuration conversion point.

determining a starting point of the uplink action interval as subframe 9 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 8 of the adjacent frame after the current configuration conversion point; or

determining the starting point of the uplink action interval as subframe 0 of the adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 9 of a second frame after the current configuration conversion point; or

determining the starting point of the uplink action interval as subframe 1 of the adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 0 of the second frame after the current configuration conversion point; or

determining the starting point of the uplink action interval as subframe 2 of the adjacent frame after the current configuration conversion point, and determining the end point of the uplink action interval as subframe 1 of the second frame after the current configuration conversion point.

determining a starting point of the uplink action interval as subframe 8 of the adjacent frame before the current configuration conversion point, and determining an end point of the uplink action interval as subframe 7 of the adjacent frame after the current configuration conversion point.

Preferably, when an end point of the downlink action interval is determined according to a table shown as follows:

and a starting point of the downlink action interval is a next subframe of an end point of a last downlink action interval determined according to the above table, one-to-one determining, for each value of the end point of the downlink action interval in the above table, an end point of the uplink reference interval according to a table shown as follows:

and determining a starting point of the uplink action interval as a next subframe of an end point of a last uplink action interval determined according to the above table; wherein a frame boundary between frame n and frame n+1 is a configuration conversion point, or frame n and frame n+1 are any two adjacent frames.

As can be seen from the above technical solution, in embodiments of present invention, in a traffic adaptive TDD system, when an actual uplink/downlink configuration of the system is changed dynamically, an uplink/downlink configuration followed by HARQ-ACK timing of a downlink subframe is changed accordingly. In present invention, a UE receives downlink data and uplink/downlink configuration changing information of a system; a configuration conversion point is determined according to the uplink/downlink configuration changing information; a downlink reference configuration used for controlling a HARQ timing relationship is determined according to actual uplink/downlink configurations before and after the configuration conversion point; HARQ-ACK corresponding to the downlink data is transmitted in an uplink subframe according to the HARQ timing relationship corresponding to the downlink reference configuration. In accordance with the method of the present invention, HARQ-ACK of more downlink subframes can be transmitted; thereby physical resources of downlink subframes are saved effectively.

Figure 1 is a schematic diagram illustrating a frame structure of a TDD system in LTE;

Figure 2 is a schematic diagram illustrating a configuration conversion point;

Figure 3 is a schematic diagram illustrating a timing relationship for a subframe after a configuration conversion point transmitting HARQ-ACK information of a downlink subframe before the configuration conversion point;

Figure 4 is a flowchart illustrating a method of downlink data HARQ timing in accordance with an embodiment of the present invention;

Figure 5 is a schematic diagram illustrating a temporary reference downlink configuration conversion point which locates between subframe n+3 and subframe n+4;

Figure 6 is a schematic diagram illustrating transmitting HARQ-ACK of downlink data with two different uplink/downlink configurations at a same uplink subframe in accordance with an embodiment of the present invention;

Figure 7 is a schematic diagram illustrating that HARQ of downlink data arrived early is transmitted late in accordance with an embodiment of the present invention;

Figure 8 is a schematic diagram illustrating idea 1 of a second method in accordance with an embodiment of the present invention;

Figure 9 is a schematic diagram illustrating timing advance of informing time of configuration change information compared with a configuration conversion point in accordance with an embodiment of the present invention;

Figure 10 is a schematic diagram illustrating idea 3 of a second method in accordance with an embodiment of the present invention;

Figure 11 is a schematic diagram illustrating idea 4 of a second method in accordance with an embodiment of the present invention;

Figure 12 is a schematic diagram illustrating timing advance of informing time of configuration change information compared with a configuration conversion point in idea 4 in accordance with an embodiment of the present invention.

Figure 13 illustrates a block diagram of a User Equipment (UE) or a Base Station (BS).

The present invention is hereinafter described in detail with reference to accompanying drawings and embodiments, so as to make the objective, technical means and merits of the present invention more apparent.

In present invention, a system informs a UE of an uplink/downlink configuration through a message; according to information about the configuration and other parameters, the system obtains configuration information followed by a timing relationship between PDSCH or SPS release and PUSCH/PUCCH bearing HARQ-ACK of the PDSCH or SPS release, e.g., the system informs the UE of the uplink/downlink configuration through broadcast signaling, or RRC signaling, or physical layer signaling; the system obtains, according to the configuration and other parameters, configuration information followed by asynchronous HARQ timing of downlink data. The system informs the UE of a new uplink/downlink configuration through a message; after receiving the new uplink/downlink configuration, the UE ascertains that the system will convert from an old configuration to the new configuration at a frame boundary, wherein the frame boundary is called a configuration conversion point.

In a LTE system, UEs of R8, R9, R10 and R11 do not support traffic adaptation, and these UEs are called backward UEs, while a UE supporting the traffic adaptation is called an advanced UE. In a traffic adaptive TDD system, an advanced UE is informed of a new traffic adaptive configuration through signaling of higher layers or physical layer, wherein the configuration is called an actual uplink/downlink configuration.

For a traffic adaptive TDD system, according to changing of an actual configuration and different positions of a downlink subframe or an uplink subframe, embodiments of the present invention propose a method for configuring a configuration followed by downlink data HARQ timing. In embodiments of the present invention, downlink data HARQ timing of some downlink subframes may follow the actual configuration, or downlink data HARQ timing of some other downlink subframes may follow a configuration which is different from the actual configuration, the configuration which is different from the actual configuration is called a downlink reference configuration. A timing relationship between PDSCH or SPS release of a downlink subframe and PUSCH/PUCCH bearing HARQ-ACK of the PDSCH or SPS release follows timing corresponding to the downlink reference configuration. In embodiments of the present invention, a configuration adjacent to and before a configuration conversion point is called an old configuration or an old uplink/downlink configuration, and a configuration adjacent to and after the configuration conversion point is called a new configuration or a new uplink/downlink configuration.

Figure 4 is a flowchart illustrating a method for transmitting HARQ-ACK of downlink data provided by the present invention. The method includes steps as follows.

In step 401: a UE receives downlink data and information indicating that an uplink/downlink configuration of a system is changed.

On the one hand, as mentioned previously, the system informs the UE of a current uplink/downlink configuration of the system through broadcast signaling, or physical layer signaling, or RRC signaling. When the uplink/downlink configuration of the system is to be changed, the system informs the UE of corresponding information, which specifically includes: uplink/downlink configuration changing or a new uplink/downlink configuration.

On the other hand, the UE receives downlink data sent from a NodeB. If the system transmits the corresponding information about the uplink/downlink configuration changing, the UE also receives the information.

In step 402: the UE detects the received downlink data, and determines HARQ-ACK information corresponding to the downlink data according to a detection result. The UE determines, according to the received uplink/downlink configuration information, a frame boundary at which the configuration is changed (i.e., a configuration conversion point) and a downlink reference configuration used for controlling a HARQ timing relationship.

The downlink reference configuration is an uplink/downlink configuration followed by PDSCH HARQ timing when an uplink subframe transmits HARQ-ACK of the downlink data. The UE may know a downlink subframe corresponding to the HARQ-ACK carried by the uplink subframe. The implementation of the present step has two methods as follows.

A first method

In the first method, a time conversion point is proposed after a configuration conversion point and is called a downlink reference configuration conversion point. Specifically, the downlink reference configuration conversion point indicates that timing for an uplink subframe carrying HARQ-ACK of downlink data follows a timing relationship corresponding to a downlink reference configuration within a certain range before the conversion point, and, the timing for the uplink subframe carrying the HARQ-ACK of the downlink data does not need to follow the timing relationship corresponding to the downlink reference configuration within a certain range after the conversion point. An uplink subframe between the configuration conversion point and the downlink reference configuration conversion point follows the downlink reference configuration.

Figure 5 is a schematic diagram illustrating a temporary reference downlink configuration conversion point which locates between subframe n+3 and subframe n+ 4.

As shown in Figure 5, letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. Dotted line 501 is a configuration conversion point, and also is a boundary between two frames. An uplink/downlink configuration of a frame before dotted line 501 is configuration 2, and an uplink/downlink configuration of a frame after dotted line 501 is configuration 1. In accordance with assumptions of the present invention, a UE ascertains that the system will use configuration 1 after dotted line 501. Dotted line 502 is a downlink configuration configuration conversion point, timing of an uplink subframe between dotted line 501 and dotted line 502 for carrying HARQ-ACK of downlink data follows a timing relationship corresponding to the downlink reference configuration.

HARQ-ACK carried by an uplink subframe after a configuration conversion point and between a downlink reference configuration conversion point follows timing corresponding to a downlink reference configuration. A position of the downlink reference configuration conversion point may have several options as follows:

(1) implementation 1

It is assumed that the configuration conversion point is between subframe n-1 and subframe n, and then the downlink reference configuration conversion point is between subframe n+3 and subframe n+ 4. The HARQ-ACK carried by the uplink subframe after the configuration conversion point and between the temporary downlink reference configuration conversion point follows timing corresponding to a downlink reference configuration given below in the present method, in present implementation, such uplink subframe locates after subframe n-1 and before subframe n+4.

(2) implementation 2

It is assumed that the configuration conversion point is between subframe n-1 and subframe n, and then the downlink reference configuration conversion point is between subframe n+8 and subframe n+ 9. The HARQ-ACK carried by the uplink subframe after the configuration conversion point and between the temporary downlink reference configuration conversion point follows timing corresponding to a downlink reference configuration given below in the present method, in present implementation, such uplink subframe locates after subframe n-1 and before subframe n+9.

(3) implementation 3

It is assumed that the configuration conversion point is between subframe n-1 and subframe n, and then the downlink reference configuration conversion point is between subframe n+4 and subframe n+ 5. The HARQ-ACK carried by the uplink subframe after the configuration conversion point and between the temporary downlink reference configuration conversion point follows timing corresponding to a downlink reference configuration given below in the present method, in present implementation, such uplink subframe locates after subframe n-1 and before subframe n+5.

(4) implementation 4

It is assumed that the configuration conversion point is between subframe n-1 and subframe n, the downlink reference configuration conversion point specified by the system for each combination of a new uplink/downlink configuration and an old uplink/downlink configuration is between subframe n+3 and subframe n+4, or between subframe n+8 and subframe n+9, or between subframe n+4 and subframe n+ 5. The present implementation includes all cases that the downlink reference configuration conversion point is between subframe n+3 and subframe n+4, or between subframe n+8 and subframe n+9, or between subframe n+4 and subframe n+5, or between subframe n+2 and subframe n+3 under different combinations of the new and old uplink/downlink configurations, which are not enumerated herein. The HARQ-ACK carried by the uplink subframe after the configuration conversion point and between the downlink reference configuration conversion point follows timing corresponding to a downlink reference configuration given below in the present method, in present implementation, such uplink subframe locates after subframe n-1 and before subframe n+x, wherein x is a left subframe adjacent to the downlink reference configuration conversion point, values of x are different according to different configuration combinations.

If an uplink subframe is after a configuration conversion point and before a downlink reference configuration conversion point, when the uplink subframe transmits HARQ-ACK of downlink data, an uplink/downlink configuration followed by PDSCH HARQ timing is called a downlink reference configuration. In the first method, there are several implementations for determining the downlink reference configuration as follows:

(1) implementation 1

If the uplink subframe is before the configuration conversion point, or the uplink subframe is after the downlink reference configuration conversion point, the PDSCH HARQ timing follows a current uplink/downlink configuration specified by the system when the uplink subframe transmits the HARQ-ACK of the downlink data.

If the uplink subframe is after the configuration conversion point and before the downlink reference configuration conversion point, an uplink/downlink configuration followed by the PDSCH HARQ timing may be any one of numbers shown in Table 3 when the uplink subframe transmits the HARQ-ACK of the downlink data.

[Table 3]

A new table consisting of numbers selected from any one of numbers within each box in Table 3 is within a protection scope of the present invention. 5x indicates that the PDSCH HARQ timing relationship follows uplink/downlink configuration 5 and the temporary downlink reference configuration conversion point is between subframe n+2 and subframe n+3; 2x indicates that the PDSCH HARQ timing relationship follows uplink/downlink configuration 2 and the downlink reference configuration conversion point is between subframe n+2 and subframe n+ 3.

If a subframe between the configuration conversion point and the downlink reference configuration conversion point is an uplink subframe actually, however, the subframe is a downlink subframe according to the downlink reference configuration, then the subframe does not carry the HARQ-ACK.

(2) implementation 2

If the uplink subframe is before the configuration conversion point, or the uplink subframe is after the downlink reference configuration conversion point, the PDSCH HARQ timing follows a current uplink/downlink configuration when the uplink subframe transmits the HARQ-ACK of the downlink data.

If the uplink subframe is after the configuration conversion point and before the downlink reference configuration conversion point, the PDSCH HARQ timing follows an old uplink/downlink configuration when the uplink subframe transmits the HARQ-ACK of the downlink data.

(3) implementation 3

If the uplink subframe is after the configuration conversion point and before the downlink reference configuration conversion point, the PDSCH HARQ timing follows a new uplink/downlink configuration when the uplink subframe transmits the HARQ-ACK of the downlink data.

(4) implementation 4

If the uplink subframe is after the configuration conversion point and before the downlink reference configuration conversion point, a configuration followed by the PDSCH HARQ timing may be a number shown in Table 4 when the uplink subframe transmits the HARQ-ACK of the downlink data.

[Table 4]

(5) implementation 5

If the uplink subframe is after the configuration conversion point and before the downlink reference configuration conversion point, a configuration followed by the PDSCH HARQ timing may be a number shown in Table 5 when the uplink subframe transmits the HARQ-ACK of the downlink data.

[Table 5]

In present implementation, when a position of the downlink reference configuration conversion point is in compliance with the aforementioned implementation 1 for determining a position of a downlink reference configuration conversion point, feedback information of more downlink data can be transmitted.

The above-mentioned is the first method for implementing step 402. A downlink reference configuration conversion point is proposed. For an uplink subframe between a configuration conversion point and the downlink reference configuration conversion point, the uplink subframe transmits HARQ-ACK feedback information according to a HARQ timing relationship corresponding to a downlink reference configuration. A second method for implementing step 402 is described hereinafter.

A second method

It should be noted that, two principles should be taken into account when HARQ-ACK feedback of downlink data is designed: 1. the same one uplink subframe cannot have different bundling windows under two or more than two configurations; 2. for a downlink subframe received early, HARQ-ACK of the downlink subframe should be transmitted with priority, that is to say, for a downlink subframe sent early, a base station know whether a UE receives correctly or not with priority.

For the first principle, an uplink subframe is to transmit HARQ-ACK feedback of some downlink subframes; a set of the downlink subframes constitutes a bundling window. In a standard, according to an uplink/downlink configuration and a position of an uplink subframe, there is a clear definition of M which is the number of downlink subframes to be fed back by the uplink subframe, wherein M is the bundling window, and a UE determines the number of HARQ-ACK resources based on a value of M. When an uplink subframe has a variety of different bundling windows under multiple configurations, it will cause blur of the value of M, and increase complexity of the standard and implementations.

A counter-example is given hereinafter to illustrate the first principle, as shown in Figure 6.

Figure 6 is a schematic diagram illustrating transmitting HARQ-ACK of downlink data with two different uplink/downlink configurations at a same uplink subframe in accordance with an embodiment of the present invention.

Letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 601 is an uplink/downlink configuration conversion point at which an uplink/downlink configuration is changed from configuration 6 to configuration 0; in accordance with a timing sequence of configuration 6, HARQ-ACK feedback of downlink subframe 602 is transmitted in uplink subframe 604; it is assumed that two radio frames after the conversion point are all configuration 0, then in accordance with a timing sequence of configuration 0, HARQ-ACK feedback of downlink subframe 603 is transmitted in uplink subframe 604, therefore, one bundling window is determined in subframe 604 respectively according to configuration 6 and configuration 0, HARQ-ACK feedback of a downlink subframe within the two bundling windows is transmitted in the same uplink subframe 604, which is contrary to the first principle.

For the second principle, a counter-example is given hereinafter to illustrate the principle, as shown in Figure 7.

Figure 7 is a schematic diagram illustrating that HARQ of downlink data arrived early is transmitted late in accordance with an embodiment of the present invention.

Letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 701 is an uplink/downlink configuration conversion point at which an uplink/downlink configuration is changed from configuration 5 to configuration 0; in accordance with a timing sequence of configuration 5, HARQ-ACK feedback of downlink subframe 702 is transmitted in uplink subframe 703; in accordance with a timing sequence of configuration 0, HARQ-ACK feedback of downlink subframe 704 is transmitted in uplink subframe 705; as such, subframe 702 is earlier than subframe 704, while the uplink subframe carrying the HARQ-ACK of subframe 702 is latter than the uplink subframe carrying the HARQ-ACK of subframe 704, which needs to be avoided when HARQ-ACK of a downlink subframe is designed.

Based on the above two principles, when a timing sequence of downlink data HARQ-ACK is designed, it is necessary to determine two points as follows:

1. a downlink reference configuration. According to downlink data HARQ timing corresponding to the configuration, a UE transmits HARQ-ACK feedback of data in a downlink subframe.

2. a downlink action interval of the downlink reference configuration. HARQ-ACK of all downlink subframes within this interval is transmitted in accordance with the timing corresponding to the downlink reference configuration; the downlink action interval of the downlink reference configuration is hereinafter called a downlink action interval.

If there is a downlink subframe outside the downlink action interval, HARQ-ACK feedback of the downlink subframe is transmitted in accordance with timing corresponding to an actual configuration of the downlink subframe. The second method discloses four ideas for determining the downlink action interval. When the downlink action interval is determined according to idea 1, or idea 3, or idea 4, there is not any other subframe between two adjacent downlink action intervals, i.e., all subframes determine downlink data HARQ-ACK timing according to corresponding downlink reference configurations; when the downlink action interval is determined according to idea 2, there may be another subframe between two adjacent downlink action intervals, in this case, a downlink subframe within the downlink action interval determines HARQ timing in accordance with the downlink reference configuration, and a downlink subframe outside the downlink action interval determines HARQ timing in accordance with an actual configuration.

A method for determining a downlink action interval is discussed hereinafter, which has four ideas as follows.

(1) idea 1

In idea 1, when an actual uplink/downlink configuration is changed among seven configurations in LTE, or among part of the configurations, a starting point and an end point of a downlink action interval are determined in accordance with same parameters. The part of the uplink/downlink configurations may be a set consisting of uplink/

downlink configurations

0, 1, 2 and 6, or may be a set consisting of

configurations

3, 4 and 5.

It is assumed that the first subframe of each frame is subframe 0, and subsequent subframes are ranked in an ascending order. Assuming that a configuration conversion point is at the end of frame n, i.e., the head of frame n+1, then the starting point of the downlink action interval is subframe X of frame n; it is assumed that the configuration conversion point is at a frame boundary between frame n+m and frame n+m+1 when the uplink/downlink configuration is changed next time, then the end point of the downlink action interval of configuration changing this time is subframe X-1 of frame m; m is an integer which is greater than or equal to 1, X is a subframe index.

According to actual uplink/downlink configurations before and after the configuration conversion point, the present idea may determine a downlink reference configuration in accordance with a method described hereinafter; HARQ of downlink data in a downlink subframe within an interval from a subframe before the configuration conversion point to a subframe before a next configuration conversion point is transmitted in accordance with the determined downlink reference configuration, wherein "actual uplink/downlink configurations" are described previously.

Figure 8 is a schematic diagram illustrating idea 1 of a second method in accordance with an embodiment of the present invention.

An example is shown in Figure 8, in which letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 802 and 804 are uplink/downlink configuration conversion points, an uplink/downlink configuration is changed from configuration 2 to configuration 1 at 802, and the uplink/downlink configuration is changed from configuration 1 to configuration 2 at 804; HARQ-ACK of a downlink subframe within an interval from subframe 801 before 802 to subframe 803 before 804 is transmitted in accordance with a timing sequence of downlink reference configuration A, which is determined according to actual configurations before and after conversion point 802. Downlink reference configuration A is determined according to one of methods for determining a downlink reference configuration described hereinafter.

Taking Figure 8 as an example, if the first subframe of each frame is subframe 0, then X=2 in the example, i.e., HARQ-ACK feedback of all downlink subframes within an interval from subframe 2 of frame n to subframe 1 of frame m follows the timing of the downlink reference configuration. X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9 are all within the protection scope of the present invention, and X=2, 3 or 4 are recommended. When X=2, 3 or 4, the aforementioned two principles are met, and HARQ-ACK information can be transmitted better.

It should be noted that, in order to ensure that a UE could obtain a downlink reference configuration for determining PDSCH HARQ-ACK timing before sending a PDSCH HARQ-ACK signal, a base station needs to inform the UE of a new uplink/downlink configuration in advance before the configuration conversion point. If timing advance for informing the UE of the new uplink/downlink configuration in advance is recorded as R, then the UE considers that the system configuration will be changed after Rms after receiving configuration changing information. In order to ensure the real-time of uplink/downlink traffic adaptive changes, a time point at which the configuration changing information is sent should be close to the configuration conversion point as far as possible. Therefore, if the system sends the configuration changing information with 10ms cycle, that R is less than 10 may better meet requirements of dynamical changing of system traffic.

The time point at which the configuration changing information is sent needs to satisfy two requirements: 1) the UE may obtain the downlink reference configuration of the PDSCH HARQ-ACK timing before sending the PDSCH HARQ-ACK signal, 2) the time point at which the configuration changing information is sent should be close to the configuration conversion point as far as possible. For example, according to these two requirements, when X=2, i.e., the example shown in Figure 8, the base station may inform the UE of the new configuration at R which is equal to 5ms and is before the conversion point no matter the system transmits the configuration changing information with 10ms cycle or 40ms cycle, i.e., the new configuration is informed to the UE in subframe 5 of frame n. In order to reduce the number of times of blind detection, for a specific value of X in the method, it may be stipulated that the base station informs the UE of the new uplink/downlink configuration in a certain subframe of each frame. For cases that X=2, 3 or 4, it may stipulated that the base station informs the UE in subframe 5 or subframe 6 of each frame that an uplink/downlink configuration conversion point will appear after 5ms or 4ms.

Figure 9 is a schematic diagram illustrating timing advance of informing time of configuration change information compared with a configuration conversion point in accordance with an embodiment of the present invention. In Figure 9, subframe 5 corresponds to subframe 907.

An example is illustrated hereinafter. Figure 9 shows the example for informing the configuration changing in advance; in the example, X=2, i.e., a starting point of a downlink action interval is subframe 2 of frame n. Letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 901 and 902 are uplink/downlink configuration conversion points, and an uplink/downlink configuration is changed from configuration 2 to configuration 1 at 901 and changed from configuration 1 to configuration 0 at 902. Feedback of a downlink subframe within an interval from subframe 903 to subframe 904 is transmitted in accordance with a timing sequence of configuration 1, wherein configuration 1 is selected according to a method for determining a downlink reference configuration described hereinafter. Feedback of a downlink subframe before subframe 903 is transmitted in accordance with a timing sequence of configuration 2; similarly, configuration 2 is selected according to the method for determining a downlink reference configuration described hereinafter. According to the timing sequence of configuration 1, HARQ-ACK feedback of downlink data in subframe 905 is transmitted in subframe 906; as a timing sequence of subframe 906 for transmitting the HARQ-ACK feedback is different from a previous uplink subframe, it is necessary for a UE to know, before subframe 906, that PDSCH HARQ-ACK feedback is transmitted according to a new uplink/downlink configuration. Therefore, a base station may inform the UE in subframe 907 that the uplink/downlink configuration will be changed at 902.

(2) idea 2

In idea 2, when an actual uplink/downlink configuration is changed among seven configurations in LTE, or among part of the configurations, a starting point and an end point of a downlink action interval are determined in accordance with same parameters. The part of the uplink/downlink configurations may be a set consisting of uplink/

downlink configurations

0, 1, 2 and 6, or may be a set consisting of

configurations

3, 4 and 5.

It is assumed that a configuration conversion point of uplink/downlink configuration changing is at the end of frame n, i.e., a starting point of the head of frame n+1, then a starting point of a downlink action interval is subframe X of frame n, and an end point of the downlink action interval is subframe X-1 of frame n+1; the end point is unrelated to a configuration conversion point of a next uplink/downlink configuration changing; a downlink reference configuration followed by a downlink subframe within the interval is determined according to actual configurations of frame n and frame n+ 1. If a next configuration conversion point is at a frame boundary between frame n+m and frame n+m+1, HARQ-ACK feedback of a downlink subframe outside the downlink action interval, i.e., the downlink subframe within an interval from subframe X of frame n+1 to subframe X-1 of frame n+m, is transmitted according to timing corresponding to the actual configuration of the downlink subframe.

An example of idea 2 is illustrated in Figure 10.

Figure 10 is a schematic diagram illustrating idea 3 of a second method in accordance with an embodiment of the present invention.

As shown in figure 10, letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 1002 and 1004 are uplink/downlink configuration conversion points; an uplink/downlink configuration is changed from configuration 2 to configuration 1 at 1002 and is changed from configuration 1 to configuration 0 at 1004. An interval from subframe 1001 before 1002 to subframe 1003 belongs to a downlink action interval, HARQ-ACK feedback corresponding to a downlink subframe within the interval is transmitted in accordance with a timing sequence of downlink reference configuration A; another interval from subframe 1007 to subframe 1008 also belongs to the downlink action interval, HARQ-ACK feedback corresponding to a downlink subframe within this interval is transmitted in accordance with a timing sequence of downlink reference configuration B; an interval from subframe 1005 to subframe 1006 does not belong to the downlink action interval, HARQ-ACK feedback corresponding to a downlink subframe within this interval is transmitted in accordance with a timing sequence of the actual configuration, i.e., configuration 1.

Timing advance of informing time of configuration changing information compared with the configuration conversion point is the same as the method discussed in idea 1, which is not repeated herein.

(3) idea 3

In idea 3, when an actual uplink/downlink configuration is changed among seven configurations in LTE, or among part of the configurations, a starting point and an end point of a downlink action interval are determined in accordance with same parameters. The part of the uplink/downlink configurations may be a set consisting of uplink/

downlink configurations

0, 1, 2 and 6, or may be a set consisting of

configurations

3, 4 and 5.

For any two adjacent frames n and n+1, a downlink reference configuration is determined according to actual uplink/downlink configurations of frame n and frame n+1, and a starting point of a downlink action interval is subframe X of frame n, and an end point of the downlink action interval is subframe X-1 of frame n+ 1. This way for determining a downlink reference configuration and a downlink action interval may be considered to be unrelated to a configuration conversion point of uplink/downlink configuration changing, and is always applied to two consecutive frames.

An example of idea 3 is illustrated in Figure 11.

Figure 11 is a schematic diagram illustrating idea 4 of a second method in accordance with an embodiment of the present invention.

As shown in figure 11, letters D and S within a subframe respectively represent a downlink subframe; letter U represents an uplink subframe. 1102 is an uplink/downlink configuration conversion point; an uplink/downlink configuration is changed from configuration 2 to configuration 1 at 1102. When X=2, according to idea 2, HARQ-ACK feedback corresponding to a downlink subframe within an interval from subframe 2 of frame n, i.e., subframe 1101, to subframe 1 of frame n+1, i.e., subframe 1103, is transmitted in accordance with a timing sequence of downlink reference configuration A; as can be seen from the discussion hereinafter, configuration A is determined according to actual configurations of frame n and frame n+ 1. HARQ-ACK feedback corresponding to a downlink subframe within an interval from subframe 1105 to subframe 1106 is transmitted in accordance with a timing sequence of downlink reference configuration B; as can be seen from the discussion hereinafter, configuration B is determined according to actual configurations of frame n+1 and frame n+ 2.

In idea 2, although it is unrelated to a position of a configuration conversion point when a downlink action interval is determined, however, the configuration conversion point is usually at a frame boundary (i.e., between two adjacent frames) when the configuration is changed, so that for a cross-frame downlink action interval, a downlink reference configuration of the downlink action interval can be still considered to be determined according to actual configurations before and after the configuration conversion point.

(4) idea 4

Based on the above two principles, when a downlink data HARQ-ACK timing sequence is designed, in idea 4, starting points and end points of downlink action intervals of different downlink reference configurations correspond to different values. It is assumed that a configuration conversion point of uplink/downlink configuration changing is at the end of frame n and the starting point of frame n+1, action intervals corresponding to different downlink reference configurations have different end points, as shown in Table 6. Table 6 shows a variety of available end subframe indexes for each downlink reference configuration when the above two principles are met.

[Table 6]

A starting point of a downlink action interval may be a next subframe of an end point of a last downlink action interval. When the uplink/downlink configuration is changed last time, it has a corresponding downlink action interval, an end point of the downlink action interval is determined according to Table 6, and a next subframe of the end point is a starting point of a current downlink action interval. If a last uplink/downlink configuration conversion point is at a frame boundary between frame p and frame p+1, then an end point of a downlink action interval of the last uplink/downlink configuration conversion point is subframe Y of frame p (or p+1), and a starting point of a downlink action interval of a uplink/downlink configuration conversion point which is at the end of frame n is subframe Y+1 of frame p (or p+1).

In idea 4, there is another method for determining a downlink action interval, in which the downlink action interval just considers actual configurations of two adjacent frames, and does not care whether a frame boundary is a configuration conversion point. According to actual configurations of two adjacent frames n and n+1 (a boundary between frame n and frame n+1 is not necessary to be a configuration conversion point), a downlink reference configuration is determined in accordance with methods described hereinafter. For different downlink reference configurations, an end point of a downlink action interval of a downlink reference configuration is determined according to Table 6, a starting point of the downlink action interval may be a next subframe of an end point of a last downlink action interval. For example, based on actual configurations of frame n and frame n+1, downlink reference configuration X is determined according to methods described below, and end point t1 of a downlink action interval is obtained according to X; based on actual configurations of frame n-1 and frame n, downlink reference configuration Y is determined according to methods described below, and an end point of a downlink action interval is obtained as subframe t2 according to Y, and a next subframe of t2 is a starting point of the downlink action interval corresponding to reference configuration X.

Timing advance of informing time of configuration changing information compared with the configuration conversion point is the same as the method discussed in idea 1. For example, it may be required that a base station informs a UE in subframe 0 or subframe 1 of a frame that the uplink/downlink configuration will be changed after 10ms or 9ms. An example is illustrated hereinafter.

Figure 12 shows the example for informing the configuration changing information in advance. Letters D and S within a subframe respectively represent a downlink subframe.

As shown in figure 12, letter U represents an uplink subframe. 1201 is an uplink/downlink configuration conversion point, and an actual uplink/downlink configuration is changed from configuration 4 to configuration 0 at 1201. A downlink reference configuration determined according to frame n and frame n+1 is configuration 4, and an end point of a downlink reference interval further determined is 1202, and then a starting point of a downlink reference interval determined according to frame n+1 and frame n+2 is 1203; it is assumed that a downlink reference configuration of the downlink reference interval of which the starting point is 1203 is configuration 0, then HARQ-ACK of downlink subframe 1203 needs to be transmitted in 1204, so that it is necessary to inform a UE of an actual configuration of a next frame in

downlink subframes

1203 or 1205 which are before 1204.

A method for determining a downlink reference configuration is discussed below. Three implementations of the method are shown as follows:

(1) implementation 1

It is assumed that an uplink/downlink configuration conversion point is at the end of frame n and a starting point of frame n+1, a UE determines a downlink reference configuration according to an actual uplink/downlink configuration. PDSCH HARQ timing of all downlink subframes within a downlink action interval should follow timing of this configuration. Table 7 shows a method for determining the downlink reference configuration.

[Table 7]

(2) implementation 2

It is assumed that an uplink/downlink configuration conversion point is at the end of frame n and a starting point of frame n+1, a UE determines a downlink reference configuration according to an actual uplink/downlink configuration. PDSCH HARQ timing of all downlink subframes within a downlink action interval should follow timing of this configuration. Table 8 shows a method for determining the downlink reference configuration. An idea of Table 8 is that TDD uplink/downlink configurations followed by the PDSCH HARQ timing are all configuration 2 when the uplink/downlink configuration is changed among 0, 1, 2 or 6. This implementation is simple and practicable.

[Table 8]

(3) implementation 3

It is assumed that an uplink/downlink configuration conversion point is at the end of frame n and a starting point of frame n+1, a UE determines a downlink reference configuration according to an actual uplink/downlink configuration. PDSCH HARQ timing of all downlink subframes within a downlink action interval should follow timing of this configuration. Table 9 shows a method for determining the downlink reference configuration. An idea of Table 9 is that a TDD uplink/downlink configuration followed by the PDSCH HARQ timing is configuration 1 when the uplink/downlink configuration is changed among 0, 1 or 6; the TDD uplink/downlink configuration followed by the PDSCH HARQ timing is configuration 2 when the uplink/downlink configuration is changed among 0, 1, 6 or 2 and at least one configuration of uplink/downlink configurations of frame n and frame n+1 is configuration 2.

[Table 9]

In implementation 2, configuration 2 is taken as the downlink reference configuration when the uplink/downlink configuration is changed among 0, 1, 2 or 6,, which is simple and practicable; but there is only one uplink subframe in uplink/downlink configuration 2, therefore, even if there are a plurality of uplink subframes in the actual uplink/downlink configuration, one uplink subframe may be used for transmission according to configuration 2, which results in unbalanced PUCCH load that one subframe has a heavy load. In order to overcome this problem, implementation 3 is proposed, which simplifies the processing approach, and avoids the unbalanced PUCCH load also.

When the above three implementations are described, it is assumed that a configuration conversion point is a frame boundary between frame n and frame n+1, i.e., a downlink reference configuration is determined according to actual reference configurations before and after the configuration conversion point.

In fact, in the second method for determining a downlink action interval in the above-mentioned

ideas

3 and 4, it is not necessary to divide the downlink action interval according to the configuration conversion point; therefore, corresponding to the second method for determining the downlink action interval in

ideas

3 and 4, frame n and frame n+1 indicate any two adjacent frames and are not necessary to be the configuration conversion point in the above three implementations for determining the downlink reference configuration (i.e., Table 7, Table 8 and Table 9). But it is also be noted that in the second method provided by the present invention, it is assumed that each configuration conversion point at which the configuration is changed is a frame boundary, therefore, a downlink reference configuration at the configuration conversion point is still determined according to actual configurations before and after the configuration conversion point.

In step 403: according to a configuration determined in step 402, PDSCH HARQ timing under the configuration is determined; and HARQ-ACK of downlink data in a downlink subframe is transmitted in a corresponding uplink subframe.

For the first method in step 402, assuming that a UE transmits the HARQ-ACK feedback in PUCCH/PUSCH of an uplink subframe n and PDSCH HARQ timing follows configuration X, the PUCCH/PUSCH indicates the HARQ-ACK of PDSCH or SPS release within a downlink subframe n-k. k∈K and values of k are defined in configuration X within Table 2, K is a set of M elements {k₀, k₁, …, k_M-1}.

For the second method in step 402, in order to transmit the HARQ-ACK of downlink data in the corresponding uplink subframe, a UE needs to know that HARQ-ACK of which downlink subframes is carried in a current uplink subframe, i.e., a reference configuration followed by the uplink subframe when the uplink subframe transmits PDSCH HARQ. An uplink action interval of the downlink reference configuration is defined; in the uplink action interval, a downlink reference configuration determined in the second method in step 402 is followed when the uplink subframe transmits the HARQ-ACK of the downlink data.

A corresponding uplink action interval may be derived according to a method for determining a downlink action interval and a downlink reference configuration. Meanwhile, there may be multiple options for the uplink action interval. Considering a configuration change case that the configuration is changed multiple times before and after, some uplink action intervals are not be adopted. A recommended method for determining the uplink action interval is hereinafter given by the present invention, in which it is still assumed that a configuration conversion point is a frame boundary between frame n and frame n+1, and a next configuration conversion point is a frame boundary between frame m and frame m+1.

For a downlink reference configuration determined by Table 7 in step 402 under cases that X=2, 3 or 4 in idea 1 of the second method in step 402, a method for determining an uplink reference interval is shown as follows:

if an actual configuration is not changed from configuration 0 to 6, and is not changed from configuration 0 to configuration 1, and is not changed from configuration 0 to configuration 2, and is not changed from configuration 6 to configuration 0, and is not changed from configuration 6 to configuration 1, and is not changed from configuration 6 to configuration 2, a starting point of the uplink action interval is subframe 8 of frame n, and an end point of the uplink action interval is subframe 7 of frame m. If the actual configuration is changed from configuration 0 to configuration 6, or is changed from configuration 0 to configuration 1, or is changed from configuration 0 to configuration 2, or is changed from configuration 6 to configuration 0, or is changed from configuration 6 to configuration 1, or is changed from configuration 6 to configuration 2, the starting point of the uplink action interval is subframe 9 of frame n, and the end point of the uplink action interval is subframe8 of frame m.

For a downlink reference configuration determined by Table 8 in step 402 in idea 1 of the second method in step 402, a method for determining an uplink reference interval is shown as follows: a starting point of the uplink action interval is subframe 8 of frame n, and an end point of the uplink action interval is subframe 7 of frame m; or the starting point of the uplink action interval is subframe 9 of frame n, and the end point of the uplink action interval is subframe 8 of frame m; or the starting point of the uplink action interval is subframe 0 of frame n+1, and the end point of the uplink action interval is subframe 9 of frame m; or the starting point of the uplink action interval is subframe 1 of frame n+1, and the end point of the uplink action interval is subframe 0 of frame m+1; or the starting point of the uplink action interval is subframe 2 of frame n+1, and the end point of the uplink action interval is subframe 1 of frame m+1.

For a downlink reference configuration determined by Table 9 in step 402 under cases that X=2, 3 or 4 in idea 1 of the second method in step 402, a method for determining an uplink reference interval is shown as follows: a starting point of the uplink action interval is subframe 8 of frame n, and an end point of the uplink action interval is subframe 7 of frame m.

For a downlink reference configuration determined by Table 7 in step 402 under cases that X=2, 3 or 4 in

ideas

2 or 3 of the second method in step 402, a method for determining an uplink reference interval is shown as follows:

if an actual configuration is not changed from configuration 0 to 6, and is not changed from configuration 0 to configuration 1, and is not changed from configuration 0 to configuration 2, and is not changed from configuration 6 to configuration 0, and is not changed from configuration 6 to configuration 1, and is not changed from configuration 6 to configuration 2, a starting point of the uplink action interval is subframe 8 of frame n, and an end point of the uplink action interval is subframe 7 of frame n+ 1. If the actual configuration is changed from configuration 0 to configuration 6, or is changed from configuration 0 to configuration 1, or is changed from configuration 0 to configuration 2, or is changed from configuration 6 to configuration 0, or is changed from configuration 6 to configuration 1, or is changed from configuration 6 to configuration 2, the starting point of the uplink action interval is subframe 9 of frame n, and the end point of the uplink action interval is subframe 8 of frame n+ 1. In idea 2, there are subframes outside the uplink action interval other than subframes included in the uplink action interval. For the downlink subframes outside the downlink action interval, HARQ-ACK feedback of each downlink subframe is transmitted in accordance with timing corresponding to an actual configuration of the downlink subframe, and thereby a corresponding uplink subframe is found to transmit the HARQ-ACK feedback of the downlink subframe.

For a downlink reference configuration determined by Table 8 in step 402 under cases that X=2, 3 or 4 in

ideas

2 or 3 of the second method in step 402, a method for determining an uplink reference interval is shown as follows: a starting point of the uplink action interval is subframe 9 of frame n, and an end point of the uplink action interval is subframe 8 of frame n+1; or the starting point of the uplink action interval is subframe 0 of frame n+1, and the end point of the uplink action interval is subframe 9 of frame n+2; or the starting point of the uplink action interval is subframe 1 of frame n+1, and the end point of the uplink action interval is subframe 0 of frame n+2; or the starting point of the uplink action interval is subframe 2 of frame n+1, and the end point of the uplink action interval is subframe 1 of frame n+ 2. There are subframes outside the uplink action interval other than subframes included in the uplink action interval. For the downlink subframes outside the downlink action interval, HARQ-ACK feedback of each downlink subframe is transmitted in accordance with timing corresponding to an actual configuration of the downlink subframe, and thereby a corresponding uplink subframe is found to transmit the HARQ-ACK feedback of the downlink subframe.

For a downlink reference configuration determined by Table 9 in step 402 under cases that X=2, 3 or 4 in

ideas

2 or 3 of the second method in step 402, a method for determining an uplink reference interval is shown as follows: a starting point of the uplink action interval is subframe 8 of frame n, and an end point of the uplink action interval is subframe 7 of frame n+ 1. There are subframes outside the uplink action interval other than subframes included in the uplink action interval. For the downlink subframes outside the downlink action interval, HARQ-ACK feedback of each downlink subframe is transmitted in accordance with timing corresponding to an actual configuration of the downlink subframe, and thereby a corresponding uplink subframe is found to transmit the HARQ-ACK feedback of the downlink subframe.

For idea 4 of the second method in step 402, a method for determining an end point of an uplink reference interval is shown in Table 10:

[Table 10]

In Table 10, for each downlink reference configuration, each parameter within an uplink action interval respectively one-to-one corresponds to each parameter under the same downlink reference configuration in Table 6. For example, corresponding to downlink reference configuration 0 in Table 6, if subframe 9 of frame n is taken as an end point of a downlink action interval, accordingly, subframe 2 of frame n+1 is taken as an end point of an uplink action interval when the downlink reference configuration is 0 according to Table 10. In addition, corresponding to the first method for determining a downlink action interval in idea 4, it is assumed that a configuration conversion point is at a frame boundary between frame n and frame n+1 when an uplink action interval is determined according to Table 10; corresponding to the second method for determining a downlink action interval in idea 4, frame n and frame n+1 indicate any two adjacent frames when an uplink action interval is determined according to Table 10.

A starting point of an uplink action interval is determined by an end point of a last uplink action interval, i.e., a next subframe of the end point of the last uplink action interval. The last uplink action interval corresponds to a last downlink action interval.

It is assumed that a UE transmits HARQ-ACK feedback in PUCCH/PUSCH of uplink subframe p within an uplink action interval and PDSCH HARQ timing follows a downlink reference configuration, the PUCCH/PUSCH indicates the HARQ-ACK of PDSCH or SPS release within downlink subframe p-k; k∈K and values of k are defined in configuration X within Table 2, K is a set of M elements {k₀, k₁, …, k_M-1}. If the HARQ-ACK feedback is not transmitted in the PUCCH/PUSCH of uplink subframe p within the uplink action interval and the PDSCH HARQ timing follows an actual configuration, the PUCCH/PUSCH indicates the HARQ-ACK of the PDSCH or SPS release within downlink subframe p-k; k∈K and values of k are defined in configuration X within Table 2, K is a set of M elements {k₀, k₁, …, k_M-1}.

Referring to figure 13, the UE 1300 may comprise a transmitter 1310, a receiver 1320 and a controller 1330 configured to control the transmitter 1310 and the receiver 1320 according to one of the embodiments of the present invention. The receiver 1320 is configured for receiving downlink data and uplink/downlink configuration changing information of a system. The controller detects the received downlink data, determines HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data, determines a configuration conversion point according to the uplink/downlink configuration changing information, and determines a downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point. The transmitter 1310 is configured for transmitting the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to the downlink reference configuration.

Referring to figure 13, the BS 1300 may comprise a transmitter 1310, a receiver 1320, and a controller 1330 configured to control the transmitter 1310 and the receiver 1320 according to one of the embodiments of the present invention. The transmitter 1310 is configured for transmitting downlink data and uplink/downlink configuration changing information of a system. The receiver 1320 is configured for receiving, from the UE, the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to a downlink reference configuration. The downlink reference configuration is determined by the UE according to the above one embodiment of the present invention.

The above descriptions are specific embodiments of the present invention. In accordance with processing of the present invention, it is ensured that HARQ-ACK of more downlink subframes is transmitted; thereby physical resources of downlink subframes are effectively saved.

The foregoing descriptions are preferred embodiments of the present invention, and are not used for limiting the protection scope of the present invention. Any modifications, equivalents, improvements, etc., made under the spirit and principle of the present invention, are all included in the protection scope of the present invention.

Claims

A method for transmitting Hybrid Automatic Repeat Request (HARQ) feedback of downlink data, the method comprising:

a. receiving, by a User Equipment (UE), downlink data and uplink/downlink configuration changing information of a system;

b. detecting the received downlink data, determining HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data, determining a configuration conversion point according to the uplink/downlink configuration changing information, and determining a downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point; and

c. transmitting the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to the downlink reference configuration.
The method of claim 1, wherein the step c comprises:

for an uplink subframe before the configuration conversion point or after a preconfigured downlink reference configuration conversion point, transmitting the HARQ-ACK corresponding to the downlink data according to a HARQ-ACK timing relationship corresponding to an current actual uplink/downlink configuration of the system; and

for an uplink subframe between the configuration conversion point and the downlink reference configuration conversion point, transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ-ACK timing relationship corresponding to the determined downlink reference configuration.
The method of claim 2, wherein the downlink reference configuration conversion point is between a subframe n+3 and a subframe n+4, or between a subframe n+8 and a subframe n+9, or between a subframe n+4 and a subframe n+5 and the configuration conversion point is between a subframe n-1 and a subframe n.
The method of claim 2, wherein corresponding to a combination of uplink/downlink configurations before and after the configuration conversion point, the downlink reference configuration conversion point is between a subframe n+3 and a subframe n+4, or between a subframe n+8 and a subframe n+9, or between a subframe n+4 and a subframe n+5, or between a subframe n+2 and a subframe n+3.
The method of any one of claims 2 to 4, wherein the downlink reference configuration is an actual uplink/downlink configuration of the system before or after the configuration conversion point.
The method of claim 1, wherein the step b comprises:

determining a downlink action interval of the downlink reference configuration according to a position of the configuration conversion point or the downlink reference configuration;

the step c comprises:

for all downlink subframes within the downlink action interval, transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ timing relationship corresponding to the downlink reference configuration.
The method of claim 6, wherein the determining a downlink action interval of the downlink reference configuration according to a position of the configuration conversion point comprises:

determining a starting point of the downlink action interval as subframe X of an adjacent frame before the current configuration conversion point, and determining an end point of the downlink action interval as subframe X-1 of an adjacent frame before a next configuration conversion point; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; or

determining the starting point of the downlink action interval as subframe X of the adjacent frame before the current configuration conversion point, and determining the end point of the downlink action interval as subframe X-1 of an adjacent frame after the current configuration conversion point; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; transmitting, for a downlink subframe outside the downlink action interval, the HARQ-ACK corresponding to the downlink data according to the current actual configuration of the system.
The method of claim 6, comprising:

receiving, by the UE, the uplink/downlink configuration changing information in a subframe closest to the configuration conversion point before transmitting HARQ-ACK corresponding to downlink data carried by a first downlink subframe within the downlink action interval.
The method of claim 7, comprising:

when X=2, 3 or 4, receiving, by the UE, the uplink/downlink configuration changing information 4ms or 5ms ahead of the configuration conversion point.
The method of claim 6, wherein the determining a downlink action interval of the downlink reference configuration according to the downlink reference configuration comprises:

determining a starting point of the downlink action interval as subframe X of a former frame in every two adjacent frames, and determining an end point of the downlink action interval as subframe X-1 of a latter frame in the every two adjacent frames; wherein X=0, 1, 2, 3, 4, 5, 6, 7, 8 or 9; or

determining the end point of the downlink action interval according to the downlink reference configuration,

the method comprising:

receiving, by the UE, the uplink/downlink configuration changing information 9ms or 10ms ahead of the configuration conversion point.
The method of claim 6, between the step b and step c, the method further comprising:

determining an uplink action interval according to a way for determining the downlink action interval and a way for determining the downlink reference configuration;

wherein the transmitting the HARQ-ACK corresponding to the downlink data according to the HARQ timing relationship corresponding to the downlink reference configuration for all downlink subframes within the downlink action interval comprises:

transmitting, by all uplink subframes within the uplink action interval, HARQ-ACK of downlink data carried by a downlink subframe corresponding to an uplink subframe within the uplink action interval according to the HARQ timing relationship corresponding to the downlink reference configuration.
A method for receiving Hybrid Automatic Repeat Request (HARQ) feedback of downlink data, the method comprising:

transmitting, by a Base Station (BS), downlink data and uplink/downlink configuration changing information of a system; and

receiving, from a User equipment (UE), the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to a downlink reference configuration,

wherein the downlink reference configuration is determined by:

detecting the received downlink data, determining HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data;

determining a configuration conversion point according to the uplink/downlink configuration changing information; and

determining the downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point.
An apparatus of a User Equipment (UE) for transmitting Hybrid Automatic Repeat Request (HARQ) feedback of downlink data, the apparatus comprising:

a receiver configured for receiving downlink data and uplink/downlink configuration changing information of a system;

a controller configured for detecting the received downlink data, determining HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data, determining a configuration conversion point according to the uplink/downlink configuration changing information, and determining a downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point; and

a transmitter configured for transmitting the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to the downlink reference configuration.
An apparatus of a Base Station (BS) for receiving Hybrid Automatic Repeat Request (HARQ) feedback of downlink data, the method comprising:

a transmitter configured for transmitting downlink data and uplink/downlink configuration changing information of a system; and

a receiver configured for receiving, from a User equipment (UE), the HARQ-ACK corresponding to the downlink data in an uplink subframe according to the HARQ timing relationship corresponding to a downlink reference configuration,

wherein the downlink reference configuration is determined by:

detecting the received downlink data, determining HARQ ACKnowledgment (HARQ-ACK) corresponding to the downlink data;

determining a configuration conversion point according to the uplink/downlink configuration changing information; and

determining the downlink reference configuration used for controlling a HARQ timing relationship according to actual uplink/downlink configurations before and after the configuration conversion point.