JP2022154664A - Terminal device, base station device, communication method, and program using extended acknowledgment - Google Patents

Abstract

To provide an automatic retransmission control technique adaptable to diversification of a communication demand.SOLUTION: A terminal device acquires, from a base station device, information indicating a resource set including a plurality of resources for transmitting uplink control information, receives user data from the base station device, identifies first information indicating whether the reception of the user data is successful or unsuccessful, and second information indicating accompanying information regarding the reception status of the user data, selects a resource associated with a combination of the first information and the second information from among a set of resources, and a value to be sent as an acknowledgment on that resource, which is associated with a combination of the first information and the second information, and transmits the uplink control information including the selected value for the selected resource to the base station device.SELECTED DRAWING: Figure 5

Description

The present invention relates to an extension technique for acknowledgment in automatic retransmission control.

In the cellular communication standard of the 3rd Generation Partnership Project (3GPP), a mechanism is used in which the transmitting side and the receiving side share whether or not the radio frame has been successfully transmitted and received using the multiple automatic repeat request (HARQ). there is According to this mechanism, for example, when a radio frame transmitted from the base station device to the terminal device is normally received, the terminal device transmits an acknowledgment (ACK) associated with the radio frame to the base station device, If the radio frame is not received normally, it transmits a negative acknowledgment (NACK) associated with the radio frame to the base station apparatus. Upon receiving NACK, the base station apparatus retransmits a radio frame containing the same data or another redundancy version radio frame generated based on the data. This makes it possible to improve the reliability of data transmission from the base station apparatus to the terminal apparatus. Similarly, it is also possible to improve the reliability of data transmission from the terminal device to the base station device.

The base station apparatus can further identify the probability of data transmission failure (frame error rate) by counting the number of times ACK is received and the number of times NACK is received. For example, when the identified frame error rate is higher than a target predetermined value, the base station apparatus changes the modulation and coding scheme (MCS) to a scheme that is less susceptible to noise and interference. In addition, when the frame error rate is sufficiently lower than the target predetermined value, the base station apparatus changes the MCS to a scheme with a relatively high communication rate and relatively susceptible to noise and interference. sell. Thereby, the reliability of communication can be improved without excessively suppressing the communication rate.

In ultra-reliable communication, it is assumed that a very low value is used as the target value of the error rate. In such a case, it is assumed that almost all frames can be normally received by the device that receives the frames. In such a case, it is assumed that most frames are received successfully and no NACKs are sent or received unless the number of ACK/NACKs sent and received is very high. For this reason, for example, when one NACK is transmitted and received due to momentary deterioration in communication quality, the second MCS with a lower communication rate than the first MCS suitable for the actual communication environment is used. can be Also, in order to determine that the first MCS suitable for the original communication environment should be used after the use of the second MCS is started, it is necessary to transmit and receive a huge number of radio frames. Thus, conventional HARQ mechanisms may not be able to adapt to the diversification of communication demands.

The present invention provides advanced techniques for automatic repeat control such as HARQ.

A terminal apparatus according to one aspect of the present invention includes acquisition means for acquiring information indicating a set of resources including a plurality of resources for transmitting uplink control information from a base station apparatus, and receiving user data from the base station apparatus. and identifying means for identifying first information indicating whether reception of the user data has succeeded or failed, and second information indicating accompanying information regarding the reception status of the user data; a resource associated with a combination of said first information and said second information, and a value to be sent as an acknowledgment on said resource, said first information and said second information being and a transmission means for transmitting uplink control information including the selected value in the selected resource to the base station apparatus, The combination of the selected resource and the value transmitted on that resource indicates the combination of the first information and the second information.

A base station apparatus according to an aspect of the present invention comprises: notification means for notifying the terminal apparatus of information indicating a set of resources including a plurality of resources for the terminal apparatus to transmit uplink control information; transmitting means for transmitting data; receiving means for receiving uplink control information from the terminal device in one of a plurality of resources included in the resource set; and a resource that receives the uplink control information. , first information indicating success or failure of reception of the user data in the terminal device, and second information indicating accompanying information regarding the reception status of the user data, based on the value transmitted as an acknowledgment in the resource. and a specifying means for specifying a combination with information.

According to the present invention, it is possible to provide an automatic retransmission control technology that can adapt to diversification of communication requests.

It is a figure which shows the structural example of a radio|wireless communications system. It is a figure which shows the hardware structural example of a base station apparatus and a terminal device. It is a figure which shows the functional structural example of a terminal device. It is a figure which shows the functional structural example of a base station apparatus. 1 is a diagram for outlining the flow of processing executed in a radio communication system; FIG.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined arbitrarily. Also, the same or similar configurations are denoted by the same reference numerals, and redundant explanations are omitted.

(System configuration)
FIG. 1 shows a configuration example of a wireless communication system according to this embodiment. This radio communication system can be a cellular communication system including base station apparatus 101 and terminal apparatus 102 . The base station apparatus 101 and the terminal apparatus 102 perform wireless communication according to any generation of 3GPP cellular wireless communication standards. For example, the base station apparatus 101 broadcasts basic control information, and the terminal apparatus 102 acquires the control information. Then, the terminal device 102 establishes a connection with the base station device 101 by executing a procedure such as a random access procedure based on the control information, for example. Thereafter, downlink user data is transmitted from the base station apparatus 101 to the terminal apparatus 102 , and uplink user data is transmitted from the terminal apparatus 102 to the base station apparatus 101 . The base station apparatus 101, for example, transmits information specifying resources (frequency/time resources) when transmitting downlink user data in downlink control information (DCI), and the terminal apparatus 102 transmits based on the DCI. receive user data at the resource identified by In addition, the base station apparatus 101 uses DCI to specify uplink resources to be used by the terminal apparatus 102, and the terminal apparatus 102 uses the specified resources to transmit uplink user data to the base station apparatus. 101.

It should be noted that the communication of user data may use combined automatic repeat request (HARQ). For example, when the terminal device 102 receives downlink user data from the base station device 101 , the terminal device 102 transmits an acknowledgment indicating the reception result to the base station device 101 . Note that the base station apparatus 101 may transmit an HARQ acknowledgment for user data transmitted from the terminal apparatus 102 . Acknowledgments generally include a positive acknowledgment (ACK) that is sent if user data is successfully received and a negative acknowledgment (NACK) that is sent if user data is unsuccessfully received. Note that, for example, when user data encoded using an error correction code is decoded by a corresponding decoding method, and a CRC (Cyclic Redundancy Check) of the decoding result determines that there is no error in the decoding result, It is determined that the user data has been successfully received. On the other hand, if the CRC does not indicate that the decoded result contains no error, it is determined that the user data has failed to be received.

In one example, the error correction code can be an LDPC (Low Density Parity Check) code or a polar code. User data of a fixed size is encoded with an error correction code to generate one codeword. Decoding may be performed on a codeword-by-codeword basis. Decoding may also use an iterative decoding method in which the decoding process for one codeword is iteratively performed (eg, using soft-decision values). In this case, it is possible to use the CRC to determine whether the decoding result obtained during the iteration of the decoding process contains an error. In this case, if the decoding result obtained midway does not contain an error, the repetition of the decoding process may be terminated.

The terminal device 102 transmits uplink control information (UCI) including an HARQ acknowledgment. At this time, the terminal device 102 transmits an acknowledgment for each codeword. UCI is transmitted by, for example, a physical uplink control channel (PUCCH). For this reason, when a plurality of codeword numbers are transmitted at once by carrier aggregation or the like, a state may arise in which a plurality of acknowledgments should also be transmitted at once. In this case, the terminal device 102 will transmit an acknowledgment with the number of bits corresponding to the number of codewords in the UCI. That is, the number of UCI bits can be variable.

At this time, the base station apparatus 101 transmits to the terminal apparatus 102 information that associates the number of bits to be transmitted in UCI with one or more resources in which the UCI is to be transmitted. After specifying the number of bits of UCI to be transmitted, the terminal device 102 specifies a resource corresponding to the number of bits based on the information, and transmits the UCI on that resource. For example, the base station apparatus 101 uses a first resource when the number of UCI bits is equal to or less than a first predetermined number of bits, and a first resource when the number of bits is greater than the first predetermined number of bits and equal to or less than a second predetermined number of bits. Information that associates the resource with the number of bits, such as a second resource, . . . , is transmitted. Then, the terminal device 102 transmits the UCI using the second resource, for example, in a situation where the UCI with the number of bits greater than the first predetermined number and equal to or less than the second predetermined number of bits should be transmitted. Note that the base station apparatus 101 can know in advance the number of bits of UCI to be transmitted by the terminal apparatus 102, for example, based on the number of codewords transmitted in parallel. You can know in advance which resources to send. Note that the UCI may include information indicating the state of the downlink channel (CSI, Channel State Information), for example. All of the information to be transmitted, such as CSI, is considered.

Note that there may be a plurality of resources associated with each number of bits, and in this case, the base station apparatus 101 can notify the terminal apparatus 102 of information specifying which of the plurality of resources should be used. . That is, the base station apparatus 101 uses resource 0 to resource N1-1 when the number of bits of the UCI is equal to or less than the first predetermined number of bits, and Information that associates resource sets and bit numbers, such as resource N1 to resource N2-1, . . . , is transmitted. Then, for example, the base station apparatus 101 should use the resource N1+3 (the fourth resource in the set of resources) when the number of UCI bits is greater than the first predetermined number of bits and equal to or less than the second predetermined number of bits. , the terminal device 102 can be notified to use the “fourth” resource, for example. Thereby, the terminal device 102 specifies the resource N1 to resource N2-1 by determining that the number of bits of the UCI to be transmitted is greater than the first predetermined number of bits and equal to or less than the second predetermined number of bits, and furthermore, A resource N1+3, which is the fourth resource among the resources, can be identified and the UCI can be transmitted on that resource.

The base station apparatus 101 can be configured to determine the modulation and coding scheme (MCS) to use on the radio link based on HARQ acknowledgments and retransmissions. For example, the target frame error rate is set based on the quality of service (for example, indicated by QCI (QoS Class Indicator) or the like) in communication with the terminal device 102 . Then, the base station apparatus 101 can set the MCS such that, for example, the ratio of the number of NACK receptions to the number of downlink user data transmissions approaches the target frame error rate. Similarly, the base station apparatus 101 may operate to change the MCS to be used by the terminal apparatus 102, for example, based on the number of reception failures (the number of NACK transmissions) relative to the number of receptions of uplink user data. good. This makes it possible to adaptively select and use an MCS suitable for the communication environment. At this time, if the frame error rate of the target is extremely low, it takes a huge number of codes to determine whether or not the MCS being used is appropriate based only on acknowledgments consisting of binary values of ACK and NACK. Words must be sent and received. Furthermore, the communication environment changes while such a large number of codewords are being transmitted and received, making it difficult to select an appropriate MCS.

In view of such circumstances, the present embodiment enhances the HARQ acknowledgment, thereby making it possible to set the MCS used in the radio link with high accuracy. In this embodiment, in one example, the acknowledgment is configured so that the information can be expressed in three or more stages instead of binary ACK and NACK.

For example, when an iterative decoding method that repeatedly performs decoding of one codeword is used, and the codeword is successfully decoded (that is, the user data is successfully received), the iterative decoding method The number of successful iterations may be sent in the acknowledgment. That is, the acknowledgment is configured so that when ACK is transmitted in the acknowledgment, the number of iterations for successful decoding is transmitted as accompanying information accompanying successful reception of the user data. For example, if the number of iterations of the process until successful decoding is small (eg, once), it can be evaluated that the radio quality is excessively good. On the other hand, if the number of iterations of processing until successful decoding is the preset maximum number of iterations, the codeword is successfully decoded, but if the radio quality degrades even a little, can be evaluated as having a certain probability of decoding failure. For this reason, the base station apparatus 101, for example, based on the acknowledgment accompanied by the accompanying information, so that the number of iterations when the decoding is successful approaches a predetermined number (for example, more than 1 and less than the maximum number of times). , can determine the MCS to use. Note that the number of iterations may be expressed with various granularities, and the more the number of possible values of the accompanying information, the finer the granularity indicating the number of iterations can be set.

In one example, the acknowledgment with accompanying information is, for example, "1" if the codeword was successfully decoded in one decoding process, and "2" if the decoding was successful in two to nine decoding processes. , 4 values, such as "3" when decoding succeeds in decoding processing from 10 times to the maximum number of iterations, and "4" when decoding fails. In addition, the acknowledgment accompanied by the accompanying information is, for example, "1" if the codeword is successfully decoded in one decoding process, "2" if the decoding is successful in two or three decoding processes, "3" if decryption is successful after 4 to 5 decryption processes, "4" if decryption is successful after 6 to 7 decryption processes, and successfully decrypted after 8 to 9 decryption processes "5" if decoding is successful, "6" if decoding is successful in 10 to 11 decoding processes, "7" if decoding is successful in decoding processes from 12 times to the maximum number of iterations, decoding has failed In some cases, it may be represented by 8 values such as "0". Note that these are only examples, and the relationship between the bit string and the number of times of decoding may be associated with a different correspondence from the above example. may be Also, in the above example, the case where the acknowledgment accompanied by the accompanying information can take the number of powers of 2 has been described, but the number of possible values may not be the number of powers of 2.

Also, when receiving user data, for example, using a known signal such as DMRS (Demodulation Reference Signal), measure the radio quality such as SINR (Signal to Interference plus Noise Ratio), and indicate the radio quality of the measurement result An acknowledgment including the value as ancillary information may be sent and received. Other quantities such as SNR (Signal to Noise Ratio), RSSI (Received Signal Strength Indicator), RSRP (Reference Signal Received Power), and RSRQ (Reference Signal Received Quality) may be used as radio quality. The radio quality may be transmitted/received as information accompanying an acknowledgment when codeword demodulation is successful, or may be transmitted/received as information accompanying a negative acknowledgment when codeword demodulation is unsuccessful. good. That is, even if the decoding is successful, whether the radio quality is insufficient, sufficient, or excessive is transmitted and received as accompanying information, so that the communication status It is possible to set the MCS suitable for Also, when decoding fails, it is possible to appropriately select which MCS to use according to radio quality. That is, when the accompanying information is not used, even if it is necessary to change the MCS significantly for successful decoding (that is, to select an MCS that is highly resistant to interference and noise), Changing the MCS can lead to persistent decoding errors. On the other hand, by sending and receiving acknowledgments with associated information, it becomes possible to set an appropriate MCS at once.

It should be noted that the radio quality information and the above iteration count information may be used in combination. For example, the acknowledgment with side information may be configured to indicate the number of iterations in case of successful decoding and the radio quality in case of unsuccessful decoding. Also, in this case, when the decoding is successful, the radio quality may be notified in addition to the number of iterations.

In this embodiment, information is given as to which resource is to be used in a resource set including a plurality of resources to be used when transmitting uplink control information. For example, the UCI includes an acknowledgment indicating whether the user data has been successfully received or not. Information (first information) indicating whether or not the user data has been successfully received and accompanying information (second information) indicating the reception status of the user data (for example, the number of iterations of the decoding process and radio quality as described above) ) to express the combination. For example, if two resources are provided and a UCI with an acknowledgment value of '0' is transmitted in the first resource, it indicates that user data reception has failed, and acknowledgment is sent in the second resource. If a UCI with a response value of '0' is sent, it may indicate that user data has been successfully received with one iteration of the decoding process. Further, when a UCI with an acknowledgment value of "1" is transmitted in the first resource, it indicates that the number of iterations of the decoding process is 2 to 9 and the user data has been successfully received. If a UCI with an acknowledgment value of '1' is sent on a resource, it may indicate that user data has been successfully received in the number of decoding process iterations from 10 to the maximum number of iterations. In this way, the relationship between the values sent as acknowledgments and the resources used can indicate the combination of the success or failure of receiving user data and the reception status. Assuming that the number of usable resources is N, the number of types of information that can be expressed by this technique is 2N. Thus, by increasing the number of available resources (“N”), more detailed information can be conveyed.

Note that when multiple acknowledgments are transmitted, the corresponding second information for each of the multiple acknowledgments may all be transmitted, for example, the highest/lowest number of iterations or the lowest/highest number of iterations. Only second information about some codewords, such as radio quality, number of iterations or average or median radio quality, may be transmitted.

For the above processing, the base station apparatus 101 of the present embodiment notifies the terminal apparatus 102 of a resource set including a plurality of resources for the terminal apparatus 102 to transmit UCI. Note that the combination of each of the plurality of resources at this time and the value transmitted as an acknowledgment in that resource is the first information indicating whether or not the user data has been successfully received and the second information indicating the reception status of the user data. associated with the information and combination of This association rule may be shared between the base station apparatus 101 and the terminal apparatus 102 in advance (for example, by being defined by a standard), or the base station apparatus 101 determines the association. The terminal device 102 may be notified.

The base station device 101 then transmits user data to the terminal device 102 . When the terminal device 102 receives user data from the base station device 101, the terminal device 102 identifies first information indicating whether the user data has been successfully received and second information indicating the reception status of the user data. Then, the terminal device 102 selects a resource associated with the combination of the first information and the second information, and a value to be transmitted as an acknowledgment in the resource from the notified resource set. , a value associated with the combination of the first information and the second information. That is, the terminal device 102 identifies a combination of a resource on which the UCI is transmitted and a value transmitted as an acknowledgment on that resource, which expresses the combination of the first information and the second information. The terminal device 102 then transmits to the base station device 101 a UCI containing the selected value as a confirmation response in the selected resource. The base station apparatus 101 waits for the UCI to be received in a plurality of resources notified to the terminal apparatus 102, and when the UCI is received in one of the resources, the resource and the value transmitted as the confirmation response in the resource A combination of the above-described first value and second value is specified based on and. In this way, it becomes possible for the terminal device 102 to notify the base station device 101 of not only whether or not user data has been successfully received, but also the reception status of the user data.

Note that the base station apparatus 101 notifies the terminal apparatus 102 of third information in which the first set of resources is separately associated with each value of the number of bits required for UCI transmission, and then , and notifies the terminal device 102 of fourth information indicating a second set of resources including a plurality of resources for the terminal device 102 to transmit uplink control information, among the first set of resources. may In this case, the terminal device 102 identifies a first set of resources associated with the number of UCI bits, e.g., indicating only successful or unsuccessful reception of user data (without accompanying information). . Then, the terminal device 102 selects the first information indicating whether or not the user data has been successfully received from the second set included in the first set, and the second information indicating the reception status of the user data. Select the resource corresponding to the combination and the value to be transmitted in that resource. Note that the above-mentioned third information is transmitted by a broadcast signal such as, for example, SIB (System Information Block), and the fourth information is individually transmitted by downlink control information (DCI), RRC (radio resource control) signaling, etc. can be sent. Note that the first set of resources corresponding to the number of bits required for UCI transmission may not be defined, and the base station apparatus 101 directly designates a plurality of resources for UCI transmission, may be notified to.

In addition, a plurality of resources for UCI transmission may be configured individually for each terminal device, and in one example, may be configured so that resources designated for a plurality of terminal devices do not overlap. Note that some resources may be set to overlap.

Note that, when the accompanying information is not used, the base station apparatus 101 can notify the terminal apparatus 102 of, for example, information designating only one resource for transmitting UCI in the conventional manner. Terminal 102, being notified of only one resource, knows that it should only send conventional acknowledgments, and can send UCI without accompanying information. Note that the base station apparatus 101 determines whether to use an acknowledgment with accompanying information or an acknowledgment without accompanying information based on, for example, the quality of service or the frame error rate value of the corresponding target. can decide. For example, when the target frame error rate is lower than a predetermined value, such as when a communication service that requires ultra-high reliability is provided, the acknowledgment with accompanying information is used. An acknowledgment without a Also, for example, the lower the target frame error rate, the greater the amount of information in the acknowledgment with accompanying information (eg, more bits, more possible values). By increasing the amount of information in the acknowledgment that accompanies the accompanying information, the reception status can be expressed in more detail. Based on this detailed information, detailed and appropriate MCS settings can be made. becomes. Here, a case will be described where the base station apparatus 101 transmits user data to the terminal apparatus 102, and the terminal apparatus 102 transmits an acknowledgment (including accompanying information as necessary) to the base station apparatus 101. , but not limited to this. That is, the enhancement of acknowledgment as described above can be used in a system in which a detailed report of the reception status is useful, such as radio link control based on the success or failure of reception of HARQ or the like.

Note that, when resources for transmitting user data on the uplink are allocated, the terminal device 102 transmits information indicating the above-described first information and second information using the resources. can be done. That is, the acknowledgment, optionally accompanied by additional information, may be multiplexed with uplink user data and transmitted together with the user data.

As described above, in the present embodiment, by enhancing the HARQ acknowledgment, the terminal device 102 can notify the base station device 101 of the reception status of user data in detail. According to this, the base station apparatus 101 can adaptively adjust the MCS and the like used for transmitting user data regardless of success or failure of reception. Therefore, based on a small number of acknowledgments, it is possible to set a radio link so that an appropriate MCS is used. Note that such advanced acknowledgments can be used in any system that uses acknowledgments such as HARQ and ARQ, and can also be applied to acknowledgments for user data transmitted from the terminal device 102. Also, any wireless communication device other than the base station device 101 and the terminal device 102 can use this method.

(Equipment configuration)
Next, a hardware configuration example of the base station apparatus 101 and the terminal apparatus 102 that execute the processes described above will be described with reference to FIG. The base station device 101 and the terminal device 102 are configured including a processor 201 , a ROM 202 , a RAM 203 , a storage device 204 and a communication circuit 205 in one example. The processor 201 is a computer including one or more processing circuits such as a general-purpose CPU (Central Processing Unit) and ASIC (Application Specific Integrated Circuit). By reading and executing the program stored therein, the overall processing of the base station apparatus 101 and the terminal apparatus 102 and each of the above-described processes are executed. The ROM 202 is a read-only memory that stores programs related to processing executed by the base station apparatus 101 and the terminal apparatus 102 and information such as various parameters. A RAM 203 is a random access memory that functions as a work space when the processor 201 executes programs and stores temporary information. The storage device 204 is configured by, for example, a detachable external storage device or the like. The communication circuit 205 is configured by, for example, a circuit for 5G wireless communication. Although one communication circuit 205 is illustrated in FIG. 2, the base station apparatus 101 and the terminal apparatus 102 can have multiple communication circuits. For example, the base station apparatus 101 and terminal apparatus 102 may have separate communication circuits 205 for each of a plurality of usable frequency bands. Also, the base station apparatus 101 and the terminal apparatus 102 may have a common communication circuit 205 for at least some of the multiple frequency bands. Further, for example, the terminal device 102 may have not only the communication circuit 205 for cellular communication, but also the communication circuit 205 compatible with other wireless communication standards such as wireless LAN.

FIG. 3 is a diagram showing a functional configuration example of the terminal device 102. As shown in FIG. The terminal device 102 has, for example, a resource information acquisition unit 301, a user data reception processing unit 302, a response generation processing unit 303, and a response transmission unit 304 as its functions. Note that FIG. 3 shows only functions particularly related to the present embodiment, and omits illustration of various other functions that the terminal device 102 may have. For example, the terminal 102 naturally has other functionality that terminals typically have in cellular communication systems. Moreover, the functional blocks in FIG. 3 are shown schematically, and each functional block may be integrated and realized, or may be further subdivided. Each function in FIG. 3 may be implemented by, for example, the processor 201 executing a program stored in the ROM 202 or the storage device 204. For example, the processor inside the communication circuit 205 may execute a predetermined It may be implemented by executing software.

The resource information acquisition unit 301 acquires from the base station apparatus 101 information on a resource set including a plurality of resources for UCI transmission, including an acknowledgment to be transmitted when user data is received. Note that the resource information acquisition unit 301 may acquire a set of resources separately for each number of bits of UCI to be transmitted, for example, in the conventional manner. In this case, resource information acquiring section 301 acquires in advance a first set of resources for each number of bits of UCI (for example, by a broadcast signal such as SIB transmitted from base station apparatus 101), and information specifying a second set specifying a plurality of resources from among the set of . Information designating the second set can be signaled by a control signal (PDCCH, physical downlink control channel) transmitted when user data is transmitted, for example by DCI. In this case, the resources identified by the second set are treated as resources for UCI transmission. Regardless of the number of bits of UCI, resource sets (including many resources) are defined in advance as resource candidates for UCI transmission, and base station apparatus 101 determines which of these to use. may be notified to the terminal device 102 from.

If some of the resource candidates for UCI transmission are designated as resources that can actually be used to transmit the UCI, for example, the resource information acquiring unit 301 can uniquely identify each resource candidate. can obtain a list of unique identification numbers. Also, if a list of resource candidates is predefined, the resource to be used may be identified by a number indicating the order in the list. In one example, if there are 16 resource candidates, the resource to be used can be specified using numbers 0 to 15 indicating their order. For example, the information '0, 7' may designate the resource candidate listed first in the list and the resource candidate listed eighth in the list as resources to be used. Note that the order of information may be given meaning. For example, when the information is notified as "0, 7", it is indicated that reception of user data has failed by transmitting "0" as an acknowledgment in the first resource. By transmitting "1" as an acknowledgment in the eighth resource, it is indicated that the radio quality is a value that is excessively good for the MCS in use, and the acknowledgment "0" or "1" in the eighth resource is transmitted, it can be indicated that the radio quality is a value suitable for MCS or that the radio quality is low. On the other hand, when the information "7, 0" is notified, it is indicated that reception of user data has failed by transmitting "0" as an acknowledgment in the eighth resource. By transmitting "1" as an acknowledgment in , it is indicated that the radio quality is a value that is excessively good for the MCS in use, and the acknowledgment "0" or "1" in the first resource is transmitted, it can be indicated that the radio quality is a value suitable for MCS or that the radio quality is low.

In addition, by specifying a plurality of resources consecutively listed in the list of resource candidates using the first resource and the number of available resources, resources that can be used for UCI transmission are specified. may For example, when there are 16 resource candidates, numbers 0 to 15 indicating the order are used, and two from the fourth resource, that is, the fourth resource and the fifth resource are selected according to the information "3, 2". It can be specified that resources are available for transmission of UCI. Also, the resources that can be used for UCI transmission may be specified by the leading number and the last number of consecutive resources. For example, the information '3, 8' may designate the 4th resource to the 9th resource as usable resources for UCI transmission. Also in this case, the order may have information.

Note that if only one resource that can be used for UCI transmission is specified, an acknowledgment without accompanying information will be transmitted as in the conventional case.

The user data reception processing unit 302 executes reception processing of user data transmitted from the base station device 101 . Note that the reception processing executed by the user data reception processing unit 302 is the same as the conventional reception processing of user data. It is configured to measure the number of iterations of processing, DMRS-based radio quality, etc., and store and output the results.

The response generation processing unit 303 first receives the first information indicating whether the user data reception processing unit 302 has successfully received the user data, and the reception status (for example, the number of iterations of the decoding process and the measured value of the radio quality). ) is specified. Then, a second combination of a UCI transmission resource and a value to be transmitted as an acknowledgment associated with the first combination of the first information and the second information is identified. Then, the response generation processing unit 303 generates a UCI including the confirmation response value corresponding to the identified second combination.

Response transmission section 304 transmits the UCI generated by response generation processing section 303 to base station apparatus 101 using the UCI transmission resource corresponding to the second combination specified as described above. .

FIG. 4 is a diagram showing a functional configuration example of the base station apparatus 101. As shown in FIG. The base station apparatus 101 has, for example, a resource information notification section 401, a user data transmission section 402, a response reception section 403, and an acknowledgment analysis section 404 as its functions. Note that FIG. 4 shows only functions particularly related to the present embodiment, and omits illustration of various other functions that the base station apparatus 101 may have. For example, the base station device 101 naturally has other functions that base station devices in a cellular communication system generally have. Moreover, the functional blocks in FIG. 4 are shown schematically, and each functional block may be integrated and realized, or may be further subdivided. 4 may be implemented by the processor 201 executing a program stored in the ROM 202 or the storage device 204, for example. It may be implemented by executing software.

The resource information notification unit 401 notifies the terminal device 102 of resource set information including a plurality of resources that can be used by the terminal device 102 to transmit UCI. Since the resource set notification method has been described in the explanation of the resource information acquisition unit 301 of the terminal device 102, the explanation is omitted here. A user data transmission unit 402 transmits user data to the terminal device 102 . This transmission of user data is done in a conventional manner and will not be described in detail here. The response receiving unit 403 receives from the terminal device 102 a UCI including an acknowledgment for user data. For example, the response receiving unit 403 waits to receive a UCI from the terminal device 102 in each of a plurality of resources available for UCI transmission notified to the terminal device 102 by the resource information notification unit 401, and receives the UCI from the plurality of resources. Receive the UCI at any of the resources. The acknowledgment analysis unit 404 identifies in which resource the UCI received by the response reception unit 403 was received and the value received as the acknowledgment in that UCI. Then, the acknowledgment analysis unit 404 generates first information indicating whether the user data has been received successfully or not based on the combination of the resource for which the UCI was received and the value received as the acknowledgment, and A combination of the user data and the second information indicating the reception status (as accompanying information added to the reception success/failure) is specified.

By using the configuration as described above, the terminal device 102 combines the first information indicating whether the reception of the user data has succeeded or failed and the second information indicating the accompanying information regarding the reception status of the user data. is indicated by a combination of the resource used to transmit the UCI and the value sent as an acknowledgment on that resource. Then, base station apparatus 101 can identify the combination of the first information and the second information described above based on the combination of the resource from which the UCI was received and the value received as the acknowledgment on that resource. According to this, not only the success or failure of user data reception but also the reception status at that time (for example, the number of iterations of the decoding process and the measured value of the radio quality) are notified to the base station apparatus 101, so a small number of acknowledgments Thus, base station apparatus 101 can quickly and appropriately perform control such as determination of MCS.

(Processing flow)
Next, an example of the flow of processing executed by the base station apparatus 101 and the terminal apparatus 102 according to this embodiment will be outlined using FIG. Note that this is an example, and the base station apparatus 101 and the terminal apparatus 102 may perform various types of processing as illustrated above.

In this process, first, the base station apparatus 101 is associated with the number of bits of the UCI via, for example, a broadcast SIB or the like, and selects a plurality of resource candidates to be used when transmitting the UCI of the number of bits. The information shown is transmitted to the terminal device 102 (S501). Note that this information may be notified individually to the terminal device 102 using, for example, an RRC message. Note that the processing of S501 may be omitted in cases such as when resource candidates that can be used for UCI transmission are determined in advance, or when resource sets for each number of bits of UCI are not defined. The base station apparatus 101 transmits, to the terminal apparatus 102, information identifying a plurality of resources that the terminal apparatus 102 can actually use for UCI transmission (S502). After that, the base station device 101 transmits user data to the terminal device 102 (S503). Information specifying a plurality of resources that the terminal device 102 can use for UCI transmission is individually transmitted to the terminal device 102 using an RRC message, DCI, or the like. Note that when the DCI notification is performed, the information of S502 is transmitted by the DCI transmitted by the PDCCH that is transmitted together with the transmission of the user data in S503. Therefore, the processes of S502 and S503 are performed by transmitting the user data once. Note that the base station apparatus 101 may notify the resources that can be used for UCI transmission for each user data transmission, or, for example, the resources that can be used for UCI transmission for a plurality of user data transmissions. resources may be notified.

Upon receiving the user data, the terminal device 102 determines the reception status of the user data (S504). Here, the terminal device 102 determines whether or not the reception of the user data (decoding of the codeword) is successful, and when transmitting an acknowledgment with accompanying information, the terminal device 102 corresponds to the content of the accompanying information. Then, the radio quality, the number of iterations of the decoding process by the iterative decoding method, and the like are determined. Then, the terminal device 102, according to the determined result of the reception status (information indicating success or failure of reception of user data and associated information), selects, from among the plurality of resources available for transmission of the UCI identified in S502, A resource to be used is identified, and a value to be transmitted as an acknowledgment in that resource is identified (S505). The terminal device 102 then transmits to the base station device 101 a UCI having the specified value as the value of the confirmation response in the specified resource (S506).

Base station apparatus 101 waits for the arrival of acknowledgments on a plurality of resources that can be used for UCI transmission, and receives UCI on any of these resources. Based on which resource the base station apparatus 101 received the UCI and the value included in the UCI as an acknowledgment value, whether or not the terminal apparatus 102 has successfully received the user data is determined. , and accompanying information (the number of iterations of the decoding process, the radio quality of the received signal, etc.) obtained when the user data is received (S507). Base station apparatus 101 can, for example, adjust MCS based on this specified information.

As described above, in the present embodiment, by constructing an acknowledgment with accompanying information, not only whether the user data has been received successfully but also whether the user data has been received successfully/failed under what circumstances. It becomes possible for the base station apparatus 101 to recognize whether. This allows the base station apparatus 101 to appropriately control the radio link with the terminal apparatus 102 in various situations.

The invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the invention.

Claims (14)

A terminal device,
Acquisition means for acquiring information indicating a set of resources including a plurality of resources for transmitting uplink control information from a base station apparatus;
User data is received from the base station apparatus, and first information indicating whether reception of the user data has succeeded or failed, and second information indicating accompanying information regarding the reception status of the user data are specified. specific means;
A resource associated with a combination of the first information and the second information from among the set of resources, and a value to be sent as an acknowledgment on the resource, the first information and selection means for selecting a value associated with the combination with the second information;
transmitting means for transmitting uplink control information including the selected value in the selected resource to the base station apparatus;
has
A combination of the selected resource and the value transmitted on that resource indicates a combination of the first information and the second information;
A terminal device characterized by: The obtaining means obtains: third information that associates a first set of resources with each number of bits of the uplink control information; obtaining from the base station apparatus fourth information indicating a second set of resources including a plurality of resources to be used for transmission of the combination with the information of No. 2;
The selecting means selects from among the second set included in the first set associated with the number of bits of the uplink control information when only indicating whether the reception of the user data was successful or unsuccessful. , selecting a resource associated with the combination of the first information and the second information and a value to be sent as an acknowledgment on that resource;
The terminal device according to claim 1, characterized by: The third information is transmitted by broadcast from the base station device, and the fourth information is transmitted individually to the terminal device,
3. The terminal device according to claim 2, characterized by: The fourth information is transmitted by downlink control information,
4. The terminal device according to claim 2 or 3, characterized by: further comprising decoding means for decoding the user data using an iterative decoding method that iteratively performs decoding of one codeword;
The combination of the first information and the second information is the failure of reception of the user data, and the success of reception when the iterative decoding method determines the success of reception when the user data is successfully received. indicating the number of iterations and either
5. The terminal device according to any one of claims 1 to 4, characterized in that: further comprising measuring means for measuring radio quality when receiving the user data;
The combination of the first information and the second information indicates a combination of at least one of failure and success of reception of the user data and a value indicating the radio quality.
The terminal device according to any one of claims 1 to 5, characterized in that: A base station device,
a notification means for notifying the terminal device of information indicating a set of resources including a plurality of resources for the terminal device to transmit uplink control information;
a transmitting means for transmitting user data to the terminal device;
receiving means for receiving uplink control information from the terminal device in any one of a plurality of resources included in the resource set;
First information indicating success or failure of reception of the user data in the terminal device based on the resource that received the uplink control information and the value transmitted as an acknowledgment in the resource and the user data identifying means for identifying a combination with second information indicating accompanying information about reception status;
A base station device characterized by having: The notifying means includes: third information that associates a first set of resources with each number of bits of the uplink control information; Notifying the terminal device of fourth information indicating a second set of resources including a plurality of resources to be used for transmission of the combination with the information of 2,
The base station apparatus according to claim 7, characterized by: The notification means transmits the third information by broadcasting, and transmits the fourth information individually to the terminal device.
The base station apparatus according to claim 8, characterized by: The notification means transmits the fourth information by downlink control information.
10. The base station apparatus according to claim 8 or 9, characterized by: A communication method performed by a terminal device,
Acquiring from the base station apparatus information indicating a resource set including a plurality of resources for transmitting uplink control information;
User data is received from the base station apparatus, and first information indicating whether reception of the user data has succeeded or failed, and second information indicating accompanying information regarding the reception status of the user data are specified. and
A resource associated with a combination of the first information and the second information from among the set of resources, and a value to be sent as an acknowledgment on the resource, the first information and selecting a value associated with the combination with the second information;
transmitting uplink control information including the selected value in the selected resource to the base station apparatus;
has
A combination of the selected resource and the value transmitted on that resource indicates a combination of the first information and the second information;
A communication method characterized by: A communication method performed by a base station device,
Notifying the terminal device of information indicating a set of resources including a plurality of resources for the terminal device to transmit uplink control information;
transmitting user data to the terminal device;
Receiving uplink control information from the terminal device in any one of a plurality of resources included in the resource set;
First information indicating success or failure of reception of the user data in the terminal device based on the resource that received the uplink control information and the value transmitted as an acknowledgment in the resource and the user data identifying a combination with second information indicating accompanying information about reception status;
A communication method comprising: on the computer installed in the terminal device,
Acquire from the base station apparatus information indicating a set of resources including a plurality of resources for transmitting uplink control information;
User data is received from the base station apparatus, and first information indicating whether reception of the user data has succeeded or failed, and second information indicating accompanying information regarding the reception status of the user data are specified. ,
A resource associated with a combination of the first information and the second information from among the set of resources, and a value to be sent as an acknowledgment on the resource, the first information and selecting a value associated with the combination with the second information;
causing uplink control information including the selected value in the selected resource to be transmitted to the base station apparatus;
A program for
A combination of the selected resource and the value transmitted on that resource indicates a combination of the first information and the second information;
A program characterized by In the computer provided in the base station equipment,
causing the terminal device to notify the terminal device of information indicating a set of resources including a plurality of resources for transmitting uplink control information;
causing user data to be transmitted to the terminal device;
receiving uplink control information from the terminal device in any one of a plurality of resources included in the resource set;
First information indicating success or failure of reception of the user data in the terminal device based on the resource that received the uplink control information and the value transmitted as an acknowledgment in the resource and the user data specify a combination with second information indicating accompanying information about the reception status;
program for.

Images