CN107046719B - Method, device and system for reducing transmission time delay of time division duplex - Google Patents
Method, device and system for reducing transmission time delay of time division duplex Download PDFInfo
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- CN107046719B CN107046719B CN201610084104.4A CN201610084104A CN107046719B CN 107046719 B CN107046719 B CN 107046719B CN 201610084104 A CN201610084104 A CN 201610084104A CN 107046719 B CN107046719 B CN 107046719B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
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- H04W72/20—Control channels or signalling for resource management
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/04—Wireless resource allocation
- H04W72/044—Wireless resource allocation based on the type of the allocated resource
- H04W72/0446—Resources in time domain, e.g. slots or frames
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/50—Allocation or scheduling criteria for wireless resources
- H04W72/51—Allocation or scheduling criteria for wireless resources based on terminal or device properties
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
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Abstract
The invention aims to provide a method, a device and a system for reducing the transmission delay of time division duplex in a base station. The method according to the invention comprises the following steps: when a request for reducing the transmission delay of time division duplex from at least one user equipment of a cell is received, acquiring configuration indication information corresponding to the cell, wherein the configuration indication information comprises information for indicating to change the data transmission direction of one or more time slots for transmitting downlink data in the initial uplink and downlink configuration; and sending the configuration indication information to the at least one user equipment, so as to reconfigure the uplink and downlink configuration of the at least one user equipment based on the configuration indication information.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method, an apparatus, and a system for reducing a transmission delay of time division duplex.
Background
According to the specifications in the 3GPP protocol, LTE system frames are 10ms in length, each frame comprising 10 subframes, each subframe being 1ms in length. Each subframe contains two slots of length 0.5 ms. In the same carrier frequency, the uplink and downlink are distinguished by time, that is, in each 10ms period, 10 subframes are available for the uplink and the downlink, and each subframe is used for either the uplink or the downlink.
In the TD-LTE system, each uplink and downlink subframe consists of 2 slots of 0.5 ms. The special subframe consists of 3 special slots: a Downlink Pilot Time Slot (DwPTS) to complete the Downlink access function of the UE; guard Period (GP), which is a buffer for signal transmission to reception; an Uplink Pilot Time Slot (UpPTS) completes an Uplink random access function of a User Equipment (UE).
Time-division duplex (TDD) provides flexible configuration without requiring a pair of spectrum resources. Currently, the TD-LTE system provides seven different semi-statically configured uplink-downlink configurations (UL-DL configurations) to allow asymmetric uplink and downlink allocations.
Reducing the transmission delay of LTE systems is an important research direction of 3GPP, and one solution to achieve the reduction is to shorten the Time Transmission Interval (TTI). For example, from the currently specified 1ms to 0.5 ms. For FDD, the timing of Hybrid automatic repeat request (HARQ) may maintain an n + k timing relationship based on the length of the TTI, where n + k is used to indicate the delay from transmission of PDSCH/PUSCH to reception of ACK/NACK messages, and the value of k is 4 in an LTE system.
For TDD, the timing of HARQ is complicated because ACK/NACK messages can be delayed due to uplink/downlink switching, because ACK/NACK in PUCCH can only be transmitted in uplink subframes, and vice versa. Therefore, a relatively large transmission delay may occur in the TD-LTE system.
Table 1 below shows downlink HARQ delay information of an exemplary TDD uplink and downlink configuration according to an existing scheme, where the uplink and downlink configuration includes 7-medium modes (configuration 0 to configuration 6) with 0.5ms as a time transmission interval, a gray part indicates that downlink data is transmitted, and a white part indicates that uplink data is transmitted. K denotes a time interval required from transmission of the PDSCH/PUSCH to reception of the ACK/NACK message.
TABLE 1
It can be seen that the K value is large in the modes of configuration 3, configuration 4 and configuration 5, and the maximum K value is 22. Therefore, based on uplink and downlink configuration of TD-LTE, in the existing scheme for reducing transmission delay by shortening TTI, in some configuration modes, transmission delay of many subframes is still large.
Disclosure of Invention
The invention aims to provide a method, a device and a system for reducing transmission delay of time division duplex.
According to an aspect of the present invention, a method for reducing transmission delay of time division duplex in a base station is provided, wherein the base station adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and performs initial uplink and downlink configuration on each user equipment in a cell, the method includes the following steps:
a, when receiving a request for reducing the transmission delay of time division duplex from at least one user equipment of a cell, obtaining configuration indication information corresponding to the cell, wherein the configuration indication information comprises information for indicating to change the data transmission direction of one or more time slots in the initial uplink and downlink configuration.
b, sending the configuration indication information to the at least one user equipment, thereby reconfiguring the uplink and downlink configuration of the at least one user equipment based on the configuration indication information.
According to an aspect of the present invention, there is also provided a method in a user equipment for reducing transmission delay of time division duplex, wherein the method comprises the following steps:
-sending a request to a base station for reducing transmission delay of time division duplex;
-receiving configuration indication information sent by a base station to reconfigure uplink and downlink configuration based on the configuration indication information.
According to an aspect of the present invention, there is also provided a base station for reducing transmission delay of time division duplex, wherein the base station adopts a frame structure and an uplink/downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and the base station includes:
an obtaining device, configured to obtain configuration indication information corresponding to a cell when receiving a request from at least one user equipment of the cell for reducing a transmission delay of time division duplex, where the configuration indication information includes information for indicating to change a data transmission direction of one or more timeslots in the initial uplink and downlink configuration. .
A sending device, configured to send the configuration indication information to the at least one ue, so as to reconfigure uplink and downlink configuration of the at least one ue based on the configuration indication information.
According to an aspect of the present invention, there is also provided a user equipment for reducing transmission delay of time division duplex, wherein the user equipment includes:
request sending means for sending a request for reducing a transmission delay of time division duplex to a base station;
and the configuration receiving device is used for receiving the configuration indication information sent by the base station so as to reconfigure the uplink and downlink configuration based on the configuration indication information.
Compared with the prior art, the invention has the following advantages: changing the data transmission direction of the time slot of one or more subframes in the initial uplink and downlink configuration in the TD-LTE system, and carrying out corresponding uplink and downlink configuration again on the user equipment with low transmission delay requirement in the cell, so that the transmission delay of the time division duplex of the part of user equipment can be reduced; moreover, according to the scheme of the invention, the new uplink configuration of the user equipment with the low transmission delay requirement does not influence other equipment in the cell to transmit data based on the initial uplink and downlink configuration, so that the interference between the user equipment with the low transmission delay requirement and the data transmission of other user equipment is avoided.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:
fig. 1 shows a flow chart of a method for reducing transmission delay for time division duplexing according to the present invention;
fig. 2 is a schematic structural diagram of a base station and a user equipment for reducing transmission delay of time division duplex according to the present invention;
fig. 3 shows a schematic diagram of frequency domain resource allocation according to an example of the present invention.
The same or similar reference numbers in the drawings identify the same or similar elements.
Detailed Description
The present invention is described in further detail below with reference to the attached drawing figures.
Fig. 1 shows a method for reducing transmission delay for time division duplexing according to the present invention. The method comprises steps S101 and S102 performed by the base station, and steps S201 and S202 performed by the user equipment.
The base station according to the present invention includes, but is not limited to, a macro base station, a micro base station, a pico base station, a home base station, etc., which are applicable to an LTE network. The user equipment includes electronic devices, including but not limited to cell phones, PDAs, etc., that can communicate with the base station directly or indirectly in a wireless manner.
The base station adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol. And the base station performs initial uplink and downlink configuration on each user equipment.
Wherein the initial uplink and downlink configuration comprises a plurality of preset uplink and downlink configuration modes.
Preferably, the configuration information corresponding to the initial uplink and downlink configuration includes information for indicating a time slot of each subframe respectively used for uplink data transmission and downlink data transmission in each uplink and downlink configuration mode.
Referring to fig. 1, in step S201, a user equipment transmits a request for reducing a transmission delay of time division duplex to a base station.
Preferably, the user equipment may transmit a request for reducing a transmission delay of time division duplex to the base station when a specific type of traffic needs to be performed. For example, when voice traffic is required, a request for reducing the transmission delay of time division duplex is sent to the base station.
In step S101, when receiving a request for reducing a transmission delay of time division duplex from at least one user equipment of a cell, a base station acquires configuration indication information corresponding to the cell.
The configuration indication information includes information for indicating to change the data transmission direction of one or more time slots used for transmitting downlink data in the initial uplink and downlink configuration.
Specifically, the manner for the base station to obtain the configuration indication information corresponding to the at least one user equipment includes any one of the following:
1) determining one or more time slots of which the data transmission direction needs to be changed based on the data transmission direction of the time slot of each subframe in the initial uplink and downlink configuration corresponding to the cell; then, based on the determined one or more time slots, corresponding configuration indication information is generated to indicate to change the data transmission direction of the one or more time slots.
Specifically, the base station may use a predetermined one or more time slots as the one or more time slots for which the direction of data transmission needs to be changed.
Preferably, the base station may select a part or all of the time slots from a plurality of predetermined time slots in which the data transmission direction can be changed as the time slots in which the data transmission direction needs to be changed.
More preferably, the base station determines a plurality of modification schemes corresponding to the time slots in which the data transmission direction can be modified, calculates delay information corresponding to each scheme, and determines the time slots in which the data transmission direction needs to be modified based on the scheme with the least average delay.
Preferably, the configuration indication information further includes indication information that one or more time slots are used as guard time slots.
According to a first example of the present invention, the frame structure adopted by the base station includes 10 subframes with length of 1ms, each subframe includes two slots with length of 0.5ms respectively, and the base station uses 0.5ms as a time transmission interval. In addition, the base station eNB _1 has performed initial uplink and downlink configuration on each user equipment in the cell _1, and data transmission directions of each time slot from the subframe 0 to the subframe 9 in the initial uplink and downlink configuration modes are as shown in table 1 above.
The user equipments UE _1, UE _2 and UE _3 in the cell _1 respectively send a request for reducing the transmission delay of time division duplex to the base station eNB _1 in step S201. Then the base station eNB _1 receives the requests from the 3 pieces of user equipment for reducing the transmission delay of the time division duplex, and generates the following configuration indication information corresponding to the cell _1 based on the time slot of the subframe in the base station that needs to change the data transmission direction: two time slots of a subframe 7 which is originally used for transmitting downlink data in a configuration 3 mode, a configuration 4 mode and a configuration 5 mode are changed into uplink data transmission; changing the second time slot of the subframe 4 which is originally used for transmitting the uplink data in the modes of configuration 0, configuration 6 and configuration 3 into the mode of transmitting the downlink data; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
The downlink HARQ delay information and the uplink HARQ delay information of the uplink and downlink configuration corresponding to the configuration indication information are respectively shown in table 2 and table 3 below, where the time slot shown by the oblique line indicates the time slot in which the data transmission direction needs to be changed, and for each time slot in which the K value changes, the change of the K value is indicated in the form of "original K value/new K value".
TABLE 2
TABLE 3
Referring to table 2, it can be seen that the maximum K value 22 of the downlink HARQ is reduced to 12, and the larger K values in the other configuration 3, configuration 4 and configuration 5 modes are reduced to below 10.
Referring to table 3, it can be seen that the K value of the first slot of subframe 2 is reduced from 6 to 5 in configuration 3, configuration 4 and configuration 5 modes.
2) And acquiring configuration indication information corresponding to the cell from one or more pieces of pre-stored candidate configuration indication information.
Specifically, the base station may randomly select one of one or more pre-stored candidate configuration indication information as the configuration indication information corresponding to the cell.
Preferably, the base station may further select suitable candidate configuration indication information as the configuration indication information corresponding to the cell based on a predetermined selection rule. Such as uplink and downlink configuration in other user equipments or based on traffic load situation of the cell.
For example, the base station includes two predetermined candidate configuration indication information config _ a and config _ B based on the initial uplink and downlink configuration shown in table 1, where config _ a indicates: two time slots of a subframe 7 for transmitting downlink data in the modes of configuration 3, configuration 4 and configuration 5 are changed into uplink data; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
Config _ B indicates: two time slots of a subframe 7 and a subframe 8 which are originally used for transmitting downlink data in a configuration 3 mode, a configuration 4 mode and a configuration 5 mode are changed into uplink data transmission; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
And the base station determines that the current cell traffic load is low, and then the base station selects Config _ B as configuration indication information corresponding to the cell to configure more subframes for transmitting uplink data.
With reference to fig. 1, in step S102, the base station sends the configuration indication information to the at least one ue, so as to reconfigure the uplink and downlink configuration of the ue based on the configuration indication information.
Preferably, the base station includes the configuration indication information in broadcast information and sends the configuration indication information to all user equipments in the cell, and marks one or more subframes where the data transmission direction needs to be changed as multicast/multicast Single Frequency Network (MBSFN) subframes, so that a user equipment in the cell, which does not request to reduce the time division duplex transmission delay, determines not to perform data transmission in the one or more subframes based on the received broadcast information.
For example, for a subframe that needs to be changed from transmitting downlink data to transmitting uplink data, the base station marks the subframe as an MBSFN subframe in the broadcast information and indicates that the subframe only includes a guard slot and an uplink symbol for transmitting uplink data.
For another example, for a subframe that needs to be changed from transmitting downlink data to transmitting uplink data, the base station indicates that the first symbol of the subframe is used for PDCCH and the other symbols are used for guard slot and uplink transmission.
Next, in step S202, the ue receives configuration indication information sent by the base station, so as to reconfigure uplink and downlink configurations based on the configuration indication information.
Continuing with the description of the foregoing first example, the user equipments UE _1, UE _2, and UE _3 respectively receive the configuration indication information sent by the base station to reconfigure the uplink and downlink configurations based on the configuration indication information, so as to be able to send uplink data and ACK/NACK messages in the subframe 7.
According to the method, the data transmission direction of the time slot of one or more subframes in the initial uplink and downlink configuration is changed in the TD-LTE system, and the corresponding uplink and downlink configuration is carried out again on the user equipment with low transmission delay requirement in the cell, so that the transmission delay of the time division duplex of the part of user equipment can be reduced; moreover, according to the method of the present invention, the new uplink configuration of the user equipment with low transmission delay requirement does not affect the transmission of data by other equipment in the cell based on the initial uplink and downlink configuration, thereby avoiding the interference between the data transmission of the user equipment with low transmission delay requirement and other equipment.
According to a preferred embodiment, before step S102, the method further comprises step S103 (not shown) performed by the base station.
In step S103, the base station creates one or more new uplink and downlink configuration modes based on the one or more time slots that need to change the data transmission direction and are indicated in the configuration indication information, so as to replace the one or more uplink and downlink configuration modes of the initial uplink and downlink configuration based on the one or more new uplink and downlink configuration modes.
For example, the base station determines that it is necessary to change the data transmission direction of two slots of the subframe 9 in the configuration 3 mode, the data transmission direction of two slots of the subframe 8 in the configuration 4 mode, and the data transmission direction of two slots of the subframe 7 in the configuration 5 mode in the initial uplink and downlink configuration shown in table 1, and creates new uplink and downlink configuration mode configuration 3s, configuration 4s, and configuration 5s based on the above to replace the initial uplink and downlink configuration mode configuration 3, configuration 4, and configuration 5, respectively. The downlink HARQ delay information of each replaced uplink and downlink configuration mode is shown in table 4 below
TABLE 4
More preferably, the base station may employ a shorter TTI, thereby further reducing transmission delay. For example, the base station adopts a 3-symbol TTI + 4-symbol TTI structure, so that in one subframe consisting of 4 symbols +3 symbols +4 symbols, which is shown below, 4 TTIs are included:
after the TTI is adopted, the K values of the subframe 1 and the subframe 6 in the configuration 2 mode, the subframe 8 in the configuration 3s mode, the subframe 7 in the configuration 4s mode, and the subframe 2 and the subframe 6 in the configuration 5s mode in the downlink HARQ delay information shown in table 4 are further reduced, as shown in table 5 below.
TABLE 5
More preferably, the base station may use one or two symbols for uplink transmission for one TTI, thereby further reducing the transmission delay. For example, the base station may employ the following TTI containing two symbols.
More preferably, the base station may use a shorter TTI for transmitting the ACK/NACK message, while still using a 0.5ms TTI on the PUSCH/PDSCH.
According to the method of the preferred embodiment, one or more new uplink and downlink configuration modes are created, and one or more uplink and downlink configuration modes of the initial uplink and downlink configuration are replaced based on the one or more new uplink and downlink configuration modes, so that the user equipment with low delay requirement can perform data transmission based on the new uplink configuration mode without being influenced by the initial uplink configuration mode.
According to a preferred embodiment of the present invention, the configuration indication information includes, in addition to information indicating one or more time slots for transmitting downlink data, in which the data transmission direction needs to be changed, information indicating frequency domain resources used by at least one user equipment requesting reduction of time division duplex transmission delay in the one or more time slots.
Preferably, for other user equipments which do not request to reduce the time division duplex transmission delay, the base station indicates, in the uplink and downlink configuration information, information of a specific bandwidth frequency domain resource used by the base station in one or more time slots in which the data transmission direction needs to be changed.
More preferably, the base station uses, as the guard frequency domain resource, a frequency domain resource with a specific bandwidth between the frequency domain resource used by the ue requesting to reduce the tdd transmission delay and the frequency domain resource used by other ues not requesting to reduce the tdd transmission delay, so that all ues in the cell do not use the guard frequency domain resource to transmit data in the time slot or time slots in which the data transmission direction needs to be changed.
For example, fig. 3 illustrates an exemplary frequency domain resource allocation scheme in accordance with the present invention. Referring to fig. 3, the frequency domain bandwidth of the system is divided into three parts, from top to bottom, bandwidth _1, bandwidth _2 and bandwidth _ 3.
Wherein, the base station has determined that each time slot of the subframe 6 and the subframe 7 is a time slot in which the data transmission direction needs to be changed, and the configuration indication information, in addition to the information indicating that the data transmission direction of each time slot of the subframe 6 and the subframe 7 needs to be changed, further includes: indicating that the user equipment requesting to reduce the time division duplex transmission delay transmits data using the frequency domain resources corresponding to band _3 in subframe 6 and subframe 7.
And for other user equipment which does not request to reduce transmission delay in the cell, the base station indicates that the base station uses frequency domain resources corresponding to the band _1 to transmit data in the subframe 6 and the subframe 7 in the uplink and downlink configuration information. And the base station uses band _2 as a protection bandwidth, so that data is not transmitted by using frequency domain resources corresponding to band _2, and interference between data transmission performed by the user equipment requesting to reduce transmission delay by using band _1 and data transmission performed by other user equipment by using band _3 is avoided.
According to the method of the preferred embodiment, the interference of the user equipment with low delay requirement and other equipment in the cell for data transmission is further reduced by allocating specific resources for the user equipment and the other equipment respectively.
Fig. 2 shows a schematic structural diagram of a base station and a user equipment for reducing transmission delay of time division duplex according to the present invention. The base station according to the present invention comprises an acquiring means 101, a transmitting means 102, and the user equipment according to the present invention comprises a request transmitting means 201 and a configuration receiving means 202.
Referring to fig. 2, an acquisition apparatus 101 transmits a request for reducing a transmission delay of time division duplex to a base station.
Preferably, the obtaining apparatus 101 may send a request for reducing the transmission delay of the time division duplex to the base station when the user equipment needs to perform a specific type of service. For example, when voice traffic is required, a request for reducing the transmission delay of time division duplex is sent to the base station.
The obtaining means 101 obtains the configuration indication information corresponding to the cell when receiving a request from at least one user equipment of the cell for reducing the transmission delay of time division duplex.
The configuration indication information includes information for indicating to change the data transmission direction of one or more time slots used for transmitting downlink data in the initial uplink and downlink configuration.
Specifically, the manner for the obtaining device 101 to obtain the configuration indication information corresponding to the at least one user equipment includes any one of the following:
1) the acquiring means 101 comprises determining means (not shown) and generating means (not shown).
The determining device determines one or more time slots for transmitting downlink data, the time slots of which the data transmission direction needs to be changed, based on the data transmission direction of the time slot of each subframe in the initial uplink and downlink configuration corresponding to the cell; then, the generating device generates corresponding configuration indication information based on the determined one or more time slots to indicate to change the data transmission direction of the one or more time slots for transmitting the downlink data.
Specifically, the base station may use a predetermined one or more time slots as the one or more time slots for which the direction of data transmission needs to be changed.
Preferably, the determining means may select a part or all of the time slots from a predetermined plurality of time slots in which the data transmission direction can be changed as the time slots in which the data transmission direction needs to be changed.
More preferably, the base station determines a plurality of modification schemes corresponding to the time slots in which the data transmission direction can be modified, calculates delay information corresponding to each scheme, and determines the time slots in which the data transmission direction needs to be modified based on the scheme with the least average delay.
Preferably, the configuration indication information further includes indication information that one or more time slots are used as guard time slots.
According to a first example of the present invention, the frame structure adopted by the base station includes 10 subframes with length of 1ms, each subframe includes two slots with length of 0.5ms respectively, and the base station uses 0.5ms as a time transmission interval. In addition, the base station eNB _1 has performed initial uplink and downlink configuration on each user equipment in the cell _1, and data transmission directions of each time slot from the subframe 0 to the subframe 9 in the initial uplink and downlink configuration modes are as shown in table 1 above.
The request sending device 201 in the user equipment UE _1, UE _2, and UE _3 in the cell _1 sends a request for reducing the transmission delay of time division duplex to the base station eNB _1, respectively. Then the base station eNB _1 receives the requests from the 3 pieces of user equipment for reducing the transmission delay of the time division duplex, respectively, and the generating means in the base station eNB _1 generates the following configuration indication information corresponding to the cell _1 based on the time slot of the subframe, which is predetermined in the base station and needs to change the data transmission direction, determined by the determining means: two time slots of a subframe 7 which is originally used for transmitting downlink data in a configuration 3 mode, a configuration 4 mode and a configuration 5 mode are changed into uplink data transmission; changing the second time slot of the subframe 4 which is originally used for transmitting the uplink data in the modes of configuration 0, configuration 6 and configuration 3 into the mode of transmitting the downlink data; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
The downlink HARQ delay information and the uplink HARQ delay information of the uplink and downlink configuration corresponding to the configuration indication information are respectively as shown in the following table 6 and table 7, where the time slot shown by the oblique line indicates the time slot in which the data transmission direction needs to be changed, and for each time slot in which the K value changes, the change of the K value is indicated in the form of "original K value/new K value".
TABLE 6
TABLE 7
Referring to table 6, it can be seen that the maximum K value 22 of the downlink HARQ is reduced to 12, and the larger K values in the other configuration 3, configuration 4, and configuration 5 modes are reduced to below 10.
Referring to table 7, it can be seen that the K value of the first slot of subframe 2 is reduced from 6 to 5 in the configuration 3, configuration 4 and configuration 5 modes.
2) The acquisition means 101 comprises sub-acquisition means (not shown).
The sub-acquisition device acquires the configuration indication information corresponding to the cell from one or more pieces of candidate configuration indication information which are prestored.
Specifically, the sub-acquisition device may randomly select one of one or more pre-stored candidate configuration indication information as the configuration indication information corresponding to the cell.
Preferably, the sub-obtaining device may further select suitable candidate configuration indication information as the configuration indication information corresponding to the cell based on a predetermined selection rule. Such as uplink and downlink configuration in other user equipments or based on traffic load situation of the cell.
For example, the base station includes two predetermined candidate configuration indication information config _ a and config _ B based on the initial uplink and downlink configuration shown in table 1, where config _ a indicates: two time slots of a subframe 7 for transmitting downlink data in the modes of configuration 3, configuration 4 and configuration 5 are changed into uplink data; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
Config _ B indicates: two time slots of a subframe 7 and a subframe 8 which are originally used for transmitting downlink data in a configuration 3 mode, a configuration 4 mode and a configuration 5 mode are changed into uplink data transmission; and taking the second time slot of the subframe 6 which is originally used for transmitting the downlink data in the modes of configuration 3, configuration 4 and configuration 5 as a protection time slot.
And, the base station determines that the current cell traffic load is low, the sub-acquisition device selects Config _ B as configuration indication information corresponding to the cell, so as to configure more subframes for transmitting uplink data.
With continued reference to fig. 2, the sending device 102 sends the configuration indication information to the at least one ue, so as to reconfigure the uplink and downlink configuration of the ue based on the configuration indication information.
Preferably, the sending device 102 includes the configuration indication information in Broadcast information and sends the configuration indication information to all user equipments in the cell, and marks one or more subframes where the data transmission direction needs to be changed as multicast/multicast Single Frequency Network (MBSFN) subframes, so that a user equipment in the cell that does not request to reduce the time division duplex transmission delay determines not to perform data transmission in the one or more subframes based on the received Broadcast information.
For example, for a subframe that needs to be changed from transmitting downlink data to transmitting uplink data, the base station marks the subframe as an MBSFN subframe in the broadcast information and indicates that the subframe only includes a guard slot and an uplink symbol for transmitting uplink data.
For another example, for a subframe that needs to be changed from transmitting downlink data to transmitting uplink data, the base station indicates that the first symbol of the subframe is used for PDCCH and the other symbols are used for guard slot and uplink transmission.
Next, the configuration receiving device 202 receives configuration indication information sent by the base station, so as to reconfigure the uplink and downlink configuration based on the configuration indication information.
Continuing with the description of the foregoing first example, the user equipments UE _1, UE _2, and UE _3 respectively receive the configuration indication information sent by the base station to reconfigure the uplink and downlink configurations based on the configuration indication information, so as to be able to send uplink data and ACK/NACK messages in the subframe 7. .
According to the scheme of the invention, the data transmission direction of the time slot of one or more subframes in the initial uplink and downlink configuration is changed in the TD-LTE system, and the corresponding uplink and downlink configuration is carried out again on the user equipment with low transmission delay requirement in the cell, so that the transmission delay of the time division duplex of the part of user equipment can be reduced; moreover, according to the scheme of the invention, the new uplink configuration of the user equipment with the low transmission delay requirement does not influence other equipment in the cell to transmit data based on the initial uplink and downlink configuration, so that the interference between the user equipment with the low transmission delay requirement and the data transmission of other user equipment is avoided.
According to a preferred embodiment, the base station further comprises a mode creating device (not shown).
The mode creating device creates one or more new uplink and downlink configuration modes based on one or more time slots which need to change the data transmission direction and are indicated in the configuration indication information, and replaces one or more uplink and downlink configuration modes of the initial uplink and downlink configuration based on the one or more new uplink and downlink configuration modes.
For example, the base station determines that it is necessary to change the data transmission direction of two slots of the subframe 9 in the configuration 3 mode, the data transmission direction of two slots of the subframe 8 in the configuration 4 mode, and the data transmission direction of two slots of the subframe 7 in the configuration 5 mode in the initial uplink and downlink configuration shown in table 1, and the mode creating device creates new uplink and downlink configuration mode configuration 3s, configuration 4s, and configuration 5s based on the change, so as to replace the initial uplink and downlink configuration mode configuration 3, configuration 4, and configuration 5, respectively. The downlink HARQ delay information of each replaced uplink and downlink configuration mode is shown in table 8 below
TABLE 8
More preferably, the base station may employ a shorter TTI, thereby further reducing transmission delay. For example, the base station adopts a 3-symbol TTI + 4-symbol TTI structure, so that in one subframe consisting of 4 symbols +3 symbols +4 symbols, which is shown below, 4 TTIs are included:
after the TTI is adopted, the K values of the subframe 1 and the subframe 6 in the configuration 2 mode, the subframe 8 in the configuration 3s mode, the subframe 7 in the configuration 4s mode, and the subframe 2 and the subframe 6 in the configuration 5s mode in the downlink HARQ delay information shown in table 8 are further reduced, as shown in table 9 below.
TABLE 9
More preferably, the base station may use one or two symbols for uplink transmission for one TTI, thereby further reducing the transmission delay. For example, the base station may employ the following TTI containing two symbols.
More preferably, the base station may use a shorter TTI for transmitting the ACK/NACK message, while still using a 0.5ms TTI on the PUSCH/PDSCH.
According to the scheme of the preferred embodiment, one or more new uplink and downlink configuration modes are created, and one or more uplink and downlink configuration modes of the initial uplink and downlink configuration are replaced based on the one or more new uplink and downlink configuration modes, so that the user equipment with low delay requirement can perform data transmission based on the new uplink configuration mode without being influenced by the initial uplink configuration mode.
According to a preferred embodiment of the present invention, the configuration indication information includes, in addition to information indicating one or more time slots for transmitting downlink data, in which the data transmission direction needs to be changed, information indicating frequency domain resources used by at least one user equipment requesting reduction of time division duplex transmission delay in the one or more time slots.
Preferably, for other user equipments which do not request to reduce the time division duplex transmission delay, the base station indicates, in the uplink and downlink configuration information, information of a specific bandwidth frequency domain resource used by the base station in one or more time slots in which the data transmission direction needs to be changed.
More preferably, the base station uses, as the guard frequency domain resource, a frequency domain resource with a specific bandwidth between the frequency domain resource used by the ue requesting to reduce the tdd transmission delay and the frequency domain resource used by other ues not requesting to reduce the tdd transmission delay, so that all ues in the cell do not use the guard frequency domain resource to transmit data in the time slot or time slots in which the data transmission direction needs to be changed.
For example, fig. 3 illustrates an exemplary frequency domain resource allocation scheme in accordance with the present invention. Referring to fig. 3, the frequency domain bandwidth of the system is divided into three parts, from top to bottom, bandwidth _1, bandwidth _2 and bandwidth _ 3.
Wherein, the base station has determined that each time slot of the subframe 6 and the subframe 7 is a time slot in which the data transmission direction needs to be changed, and the configuration indication information, in addition to the information indicating that the data transmission direction of each time slot of the subframe 6 and the subframe 7 needs to be changed, further includes: indicating that the user equipment requesting to reduce the time division duplex transmission delay transmits data using the frequency domain resources corresponding to band _3 in subframe 6 and subframe 7.
And for other user equipment which does not request to reduce transmission delay in the cell, the base station indicates that the base station uses frequency domain resources corresponding to the band _1 to transmit data in the subframe 6 and the subframe 7 in the uplink and downlink configuration information. And the base station uses band _2 as a protection bandwidth, so that data is not transmitted by using frequency domain resources corresponding to band _2, and interference between data transmission performed by the user equipment requesting to reduce transmission delay by using band _1 and data transmission performed by other user equipment by using band _3 is avoided.
According to the scheme of the preferred embodiment, specific resources are allocated to the user equipment with low delay requirement and other equipment in the cell respectively, so that the interference of the user equipment and other equipment in the cell in data transmission is further reduced.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or means recited in the system claims may also be implemented by one unit or means in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.
Claims (13)
1. A method for reducing HARQ transmission delay of time division duplex in a base station, wherein the base station adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and performs initial uplink and downlink configuration on each user equipment in a cell, the method comprises the following steps:
a, when receiving a request for reducing HARQ transmission delay of time division duplex from at least one user equipment of a cell, acquiring configuration indication information corresponding to the cell, wherein the configuration indication information comprises information for indicating to change the data transmission direction of one or more time slots for transmitting downlink data in the initial uplink and downlink configuration;
b, sending the configuration indication information to the at least one user equipment, so as to reconfigure uplink and downlink configuration of the at least one user equipment based on the configuration indication information;
wherein the method further comprises the steps of:
-creating one or more new uplink and downlink configuration modes based on the one or more timeslots for which the data transmission direction needs to be changed indicated in the configuration indication information, so as to replace the one or more uplink and downlink configuration modes of the initial uplink and downlink configuration based on the new uplink and downlink configuration modes.
2. The method of claim 1, wherein the step a comprises the steps of:
a1, determining one or more time slots for transmitting downlink data, the time slots requiring to change the data transmission direction, based on the data transmission direction of the time slot of each subframe in the initial uplink and downlink configuration corresponding to the cell;
a2 generates corresponding configuration indication information based on the determined one or more time slots to indicate to change the data transmission direction of the one or more time slots for transmitting the downlink data.
3. The method of claim 1 or 2, wherein the configuration indication information comprises indication information of one or more time slots as guard time slots.
4. The method of claim 1, wherein the step a comprises the steps of:
-obtaining configuration indication information corresponding to the cell from one or more pre-stored candidate configuration indication information.
5. The method of claim 1, wherein the configuration indication information includes, in addition to information indicating one or more time slots for transmitting downlink data for which a change of a data transmission direction is required, information indicating frequency domain resources used by at least one user equipment requesting a reduction of time division duplex transmission delay in the one or more time slots.
6. A method in a user equipment for reducing HARQ transmission latency for time division duplexing, wherein the method comprises the steps of:
-sending a request to a base station for reducing HARQ transmission delay for time division duplexing;
-receiving configuration indication information sent by a base station to reconfigure uplink and downlink configurations based on the configuration indication information;
the configuration indication information comprises information for indicating to change the data transmission direction of one or more time slots used for transmitting downlink data in the initial uplink and downlink configuration;
the user equipment adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and replaces one or more uplink and downlink configuration modes of initial uplink and downlink configuration based on one or more created new uplink and downlink configuration modes.
7. A base station for reducing HARQ transmission delay of time division duplex, wherein the base station adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and performs initial uplink and downlink configuration on each user equipment in a cell, the base station comprises:
an obtaining device, configured to obtain configuration indication information corresponding to a cell when receiving a request from at least one user equipment of the cell for reducing HARQ transmission delay of time division duplex, where the configuration indication information includes information for indicating to change a data transmission direction of one or more time slots used for transmitting downlink data in the initial uplink and downlink configuration;
a sending device, configured to send the configuration indication information to the at least one ue, so as to reconfigure uplink and downlink configuration of the at least one ue based on the configuration indication information;
wherein the base station further comprises:
and the mode creating device is used for creating one or more new uplink and downlink configuration modes based on one or more time slots which are indicated in the configuration indication information and need to change the data transmission direction, and replacing one or more uplink and downlink configuration modes of the initial uplink and downlink configuration based on the new uplink and downlink configuration modes.
8. The base station of claim 7, wherein the obtaining means comprises:
a determining device, configured to determine, based on a data transmission direction of a time slot of each subframe in initial uplink and downlink configuration corresponding to the cell, one or more time slots for transmitting downlink data for which the data transmission direction needs to be changed;
and generating means, configured to generate, based on the determined one or more time slots, corresponding configuration indication information to indicate to change a data transmission direction of the one or more time slots for transmitting the downlink data.
9. The base station according to claim 7 or 8, wherein the configuration indication information comprises indication information of one or more time slots as guard time slots.
10. The base station of claim 7, wherein the obtaining means comprises:
and the sub-acquisition device is used for acquiring the configuration indication information corresponding to the user equipment from one or more pieces of pre-stored candidate configuration indication information.
11. The base station of claim 7, wherein the configuration indication information includes, in addition to information indicating one or more time slots for transmitting downlink data, in which the data transmission direction needs to be changed, information indicating frequency domain resources used by at least one user equipment requesting reduction of time division duplex transmission delay in the one or more time slots.
12. A user equipment for reducing time division duplex HARQ transmission latency, wherein the user equipment comprises:
request sending means for sending a request for reducing a HARQ transmission delay of time division duplex to a base station;
a configuration receiving device, configured to receive configuration indication information sent by a base station, so as to reconfigure uplink and downlink configurations based on the configuration indication information;
the configuration indication information comprises information for indicating to change the data transmission direction of one or more time slots used for transmitting downlink data in the initial uplink and downlink configuration;
the user equipment adopts a frame structure and an uplink and downlink configuration mode of a TD-LTE system specified by a 3GPP protocol, and replaces one or more uplink and downlink configuration modes of initial uplink and downlink configuration based on one or more created new uplink and downlink configuration modes.
13. A communication system, wherein the communication system comprises at least one base station according to any of claims 7 to 11 and at least one user equipment according to claim 12.
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| CN109802771B (en) * | 2017-11-17 | 2021-01-22 | 电信科学技术研究院 | Data transmission method, terminal, base station and storage medium |
| RU2758106C1 (en) * | 2017-11-24 | 2021-10-26 | Гуандун Оппо Мобайл Телекоммьюникейшнз Корп., Лтд. | Method for data transmission, terminal apparatus and network apparatus |
| CN113056942B (en) * | 2018-11-26 | 2024-04-26 | 高通股份有限公司 | Half duplex processing in carrier aggregation |
| CN113038605B (en) * | 2019-12-24 | 2023-01-17 | 中国电信股份有限公司 | Method and device for scheduling uplink channel and computer readable storage medium |
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