JP7477479B2 - Terminal device, base station device, communication method, and program using extended acknowledgement response - Google Patents

Description

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

The cellular communication standard of the Third Generation Partnership Project (3GPP) uses a mechanism in which the transmitting side and the receiving side share whether or not the transmission and reception of a wireless frame was successful by using a composite automatic repeat request (HARQ). According to this mechanism, for example, if a wireless frame transmitted from a base station device to the terminal device is received normally, the terminal device transmits an acknowledgement (ACK) associated with the wireless frame to the base station device, and if the wireless frame is not received normally, the terminal device transmits a negative acknowledgement (NACK) associated with the wireless frame to the base station device. Then, when the base station device receives a NACK, it retransmits a wireless frame containing the same data or a different wireless frame of a redundancy version generated based on the data. This can improve the reliability of data transmission from the base station device to the terminal device. Similarly, the reliability of data transmission from the terminal device to the base station device can also be improved.

The base station device can further determine the probability of data transmission failure (frame error rate) by, for example, tallying up the number of times ACK is received and the number of times NACK is received. For example, if the determined frame error rate is higher than a target predetermined value, the base station device changes the modulation and coding scheme (MCS) to a scheme that is less susceptible to the effects of noise and interference. Also, if the frame error rate is sufficiently lower than the target predetermined value, the base station device can change the MCS to a scheme with a relatively high communication rate and relatively susceptible to the effects of noise and interference. This makes it possible to improve the reliability of communication without excessively suppressing the communication rate.

In ultra-reliable communication, it is assumed that an extremely low value is used as the target value of the error rate. In such a case, it is assumed that the device receiving the frames can receive almost all frames normally. In such a case, it is assumed that most frames are received normally and NACK is not transmitted or received unless the number of ACK/NACK transmissions is very large. For this reason, for example, when one NACK is transmitted or received due to a momentary deterioration in communication quality, a second MCS with a lower communication rate than the first MCS appropriate for the actual communication environment may be used. Also, after the second MCS is started to be used, a huge number of wireless frames must be transmitted and received in order to determine that the first MCS appropriate for the original communication environment should be used. In this way, the conventional HARQ mechanism may not be able to adapt to the diversification of communication requirements.

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

A terminal device according to one aspect of the present invention has an acquisition means for acquiring from a base station device information associating a number of bits of uplink control information to be transmitted to a base station device with a resource to which the uplink control information of said number of bits is to be transmitted, and information indicating a decision as to whether or not to transmit associated information regarding a reception status of the user data, the decision being determined based on a service quality associated with the user data; a determination means for determining a second number of bits of uplink control information to be transmitted to the base station device based on the information indicating the decision and a first number of bits required to transmit an acknowledgement accompanied by the associated information; and a transmission means for transmitting the uplink control information including the acknowledgement to the base station device using the resource associated with the second number of bits.

A base station device according to one aspect of the present invention has a decision means for deciding whether or not to transmit associated information regarding a reception status of user data based on a service quality associated with the user data, a notification means for notifying the terminal device of information correlating a number of bits of uplink control information to be received from the terminal device with a resource to which the uplink control information of said number of bits is to be transmitted , and information indicating the decision , a transmission means for transmitting user data to the terminal device, and a reception means for receiving an acknowledgment response accompanied by associated information regarding the reception status of the user data in the terminal device, the reception means receiving the acknowledgment response in the resource associated with a second number of bits specified as the number of bits required for transmitting uplink control information based on the information indicating the decision and a first number of bits required for transmitting the acknowledgment response.

The present invention provides automatic retransmission control technology that can adapt to the diversification of communication requirements.

FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. FIG. 2 is a diagram illustrating an example of the hardware configuration of a base station device and a terminal device. FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal device. FIG. 2 is a diagram illustrating an example of a functional configuration of a base station device. 1 is a diagram for outlining the flow of processing executed in a wireless communication system;

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. In addition, the same reference numbers are used for the same or similar configurations, and duplicate descriptions will be omitted.

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

Note that a composite automatic repeat request (HARQ) may be used in the communication of user data. For example, when the terminal device 102 receives downlink user data from the base station device 101, it transmits an acknowledgement indicating the result of the reception to the base station device 101. Note that the base station device 101 may transmit an acknowledgement of HARQ for the user data transmitted from the terminal device 102. The acknowledgement generally includes a positive acknowledgement (ACK) transmitted when the reception of the user data is successful, and a negative acknowledgement (NACK) transmitted when the reception of the user data is unsuccessful. Note that, for example, when user data encoded using an error correction code is decoded by a corresponding decoding method, and the decoding result is determined to be free of errors by a CRC (Cyclic Redundancy Check) on the decoding result, it is determined that the reception of the user data is successful. On the other hand, when the CRC does not result in a state in which the decoding result does not include errors, it is determined that the reception of the user data is unsuccessful.

In one example, the error correction code may be a Low Density Parity Check (LDPC) code or a polar code. A certain size of user data is encoded by the error correction code to generate one codeword. Decoding may be performed on a codeword-by-codeword basis. Alternatively, an iterative decoding method may be used in which a decoding process for one codeword is repeatedly executed (e.g., using soft decision values). In this case, a CRC may be used to determine whether an error is contained in the decoding result obtained during the iteration of the decoding process. In this case, if no error is contained in the decoding result obtained during the iteration, the iteration of the decoding process may be terminated.

The terminal device 102 transmits an HARQ acknowledgment in uplink control information (UCI). At this time, the terminal device 102 transmits an acknowledgment for each codeword. The UCI is transmitted, for example, by a physical uplink control channel (PUCCH). For this reason, when multiple codewords are transmitted simultaneously, for example by carrier aggregation, multiple acknowledgments may also need to be transmitted simultaneously. In this case, the terminal device 102 transmits an acknowledgment in the UCI with a number of bits corresponding to the number of codewords. That is, the number of bits of the UCI may be variable.

At this time, the base station device 101 transmits to the terminal device 102 information associating the number of bits to be transmitted in the UCI with one or more resources to transmit the UCI. Then, when the terminal device 102 specifies the number of bits of the UCI to be transmitted, it specifies a resource corresponding to the number of bits based on the information, and transmits the UCI on the resource. For example, the base station device 101 transmits information associating the resource with the number of bits, such as a first resource when the number of bits of the UCI is equal to or less than a first predetermined number of bits, a second 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, and so on. Then, the terminal device 102 transmits the UCI using the second resource, for example, in a situation where a UCI that is greater than the first predetermined number of bits and equal to or less than a second predetermined number of bits should be transmitted. In addition, the base station device 101 can know in advance the number of UCI bits to be transmitted by the terminal device 102 based on, for example, the number of codewords transmitted in parallel, and can therefore recognize in advance the resources from which the terminal device 102 will transmit the UCI.

Note that there may be multiple resources associated with each number of bits, and in this case, the base station device 101 may notify the terminal device 102 of information specifying which of the multiple resources should be used. That is, the base station device 101 transmits information associating a set of resources with the number of bits, such as resource 0 to resource N1-1 when the number of bits of the UCI is equal to or less than a first predetermined number of bits, resource N1 to resource N2-1 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, etc. Then, for example, when the base station device 101 determines that the number of bits of the UCI is greater than the first predetermined number of bits and equal to or less than a second predetermined number of bits and that resource N1+3 (the fourth resource in the set of resources) should be used, it can notify the terminal device 102 to use, for example, the "fourth" resource. As a result, the terminal device 102 can identify resources N1 to N2-1 because the number of bits of the UCI to be transmitted is greater than the first predetermined number of bits and less than or equal to the second predetermined number of bits, and can further identify the fourth resource among these resources, resource N1+3, and transmit the UCI using that resource.

The base station device 101 may be configured to determine the modulation and coding scheme (MCS) to be used in the wireless link based on the HARQ acknowledgement and retransmission. For example, a target frame error rate is set based on the service quality (for example, indicated by QCI (QoS Class Indicator) or the like) in the communication with the terminal device 102. The base station device 101 may set the MCS so that the ratio of the number of times NACK is received to the number of times downlink user data is transmitted approaches the target frame error rate. Similarly, the base station device 101 may operate to change the MCS to be used by the terminal device 102 based on the number of times reception failure (the number of times NACK is transmitted) to the number of times uplink user data is received. This makes it possible to adaptively select and use an MCS suitable for the communication environment. In this case, if the target frame error rate is extremely low, a huge number of codewords must be transmitted and received in order to determine whether the MCS being used is appropriate based only on the acknowledgement consisting of two values of ACK and NACK. Furthermore, the communication environment may change while such a large number of codewords are being transmitted and received, making it difficult to select an appropriate MCS.

In this embodiment, in consideration of these circumstances, the HARQ acknowledgment response is enhanced, thereby making it possible to set the MCS used in the radio link with high accuracy. In one example, the acknowledgment response is configured to be able to express information in three or more stages, rather than the two values of ACK and NACK.

For example, in the case where an iterative decoding method is used in which decoding of one codeword is performed repeatedly, when decoding of the codeword is successful (i.e., user data is successfully received), the number of iterations at which decoding was successful in the iterative decoding method may be included in the acknowledgement and transmitted. That is, when an ACK is transmitted in the acknowledgement, the acknowledgement is configured so that the number of iterations required to successfully decode is transmitted as associated information associated with the successful reception of the user data. For example, if the number of iterations required to successfully decode is small (e.g., one time), it can be evaluated that the wireless quality is excessively good. On the other hand, if the number of iterations required to successfully decode is the maximum number of iterations set in advance, it can be evaluated that the codeword was successfully decoded, but there is a certain degree of probability that decoding will fail if the wireless quality deteriorates even slightly. For this reason, the base station device 101 can determine the MCS to be used based on the acknowledgement with associated information so that the number of iterations required to successfully decode is close to a predetermined number (e.g., more than one time and less than the maximum number). The number of iterations may be expressed at various granularities, and the more possible values the associated information can have, the finer the granularity of the number of iterations can be set.

In one example, the acknowledgement with accompanying information may be expressed as four values (2 bits). In this case, for example, the acknowledgement may be "01" if the codeword is successfully decoded in one decoding process, "10" if the codeword is successfully decoded in two to nine decoding processes, "11" if the codeword is successfully decoded in ten to the maximum number of iterations, or "00" if the codeword fails to be decoded. Alternatively, the acknowledgement with accompanying information may be expressed as eight values (3 bits). In this case, the following confirmation response may be transmitted if the codeword is successfully decoded in one decoding process: "001", if the codeword is successfully decoded in two or three decoding processes: "010", if the codeword is successfully decoded in four or five decoding processes: "011", if the codeword is successfully decoded in six or seven decoding processes: "100", if the codeword is successfully decoded in eight or nine decoding processes: "101", if the codeword is successfully decoded in ten or eleven decoding processes: "110", if the codeword is successfully decoded in ten or eleven decoding processes: "111", if the codeword is successfully decoded in twelve or a maximum number of iterations: "000". Note that these are merely examples, and the relationship between the bit string and the number of decoding processes may be associated in a different correspondence from the above example, and for example, a confirmation response of four or more bits may be used. In the above example, a case has been described in which the confirmation response accompanied by accompanying information can take a number of values that is a power of two, but the number of possible values does not have to be a power of two.

In addition, when receiving user data, a radio quality such as SINR (Signal to Interference plus Noise Ratio) may be measured using a known signal such as DMRS (Demodulation Reference Signal), and an acknowledgment response including a value indicating the radio quality of the measurement result as associated information may be transmitted and received. Note that 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 the radio quality. Note that this radio quality may be transmitted and received as information accompanying a positive response when demodulation of the codeword is successful, or may be transmitted and received as information accompanying a negative response when demodulation of the codeword is unsuccessful. That is, even if decoding is successful, whether the radio quality is insufficient, sufficient, or excessive is transmitted and received as associated information, making it possible to set an MCS suitable for the communication situation. Also, when decoding fails, it is possible to appropriately select which MCS to use depending on the radio quality. In other words, if the associated information is not used, even if it is necessary to significantly change the MCS to successfully decode (i.e., select an MCS that is highly resistant to interference and noise), gradually changing the MCS may result in continued decoding errors. On the other hand, by sending and receiving an acknowledgment response accompanied by associated information, it becomes possible to set an appropriate MCS all at once.

In addition, this wireless quality information may be used in combination with the above-mentioned information on the number of iterations. For example, an acknowledgment response accompanied by accompanying information may be configured so that the number of iterations is notified if decoding is successful, and the wireless quality is notified if decoding is unsuccessful. In this case, when decoding is successful, the wireless quality may be notified in addition to the number of iterations.

The base station device 101 may determine whether to use an acknowledgment response with accompanying information or an acknowledgment response without accompanying information, for example, based on the service quality or the frame error rate value of the corresponding target. The base station device 101 then notifies the terminal device 102 of the determined content. This allows the terminal device 102 to recognize whether to use only ACK/NACK as in the past, or to use an acknowledgment response with accompanying information to report the communication status in more detail. For example, when a communication service requiring ultra-high reliability is provided, and the frame error rate of the target is lower than a predetermined value, an acknowledgment response with accompanying information may be used, and an acknowledgment response without accompanying information may be used in other cases. In addition, the lower the frame error rate of the target, the greater the amount of information in the acknowledgment response with accompanying information (for example, the number of bits may be increased, or the number of possible values may be increased). By increasing the amount of information in the acknowledgment response with accompanying information, the reception status is expressed in more detail, and it becomes possible to set a detailed and appropriate MCS based on the detailed information. Here, a case will be described in which the base station device 101 transmits user data to the terminal device 102, and the terminal device 102 transmits an acknowledgment response (including associated information as necessary) to the base station device 101, but this is not limited to the above. In other words, the above-mentioned advanced acknowledgment response can be used in a system in which detailed reports of reception conditions are useful, such as control of radio links based on the success or failure of reception of HARQ, etc.

When the terminal device 102 of this embodiment receives downlink user data from the base station device 101, the terminal device 102 transmits to the base station device 101 an acknowledgment response indicating the reception status of the user data, and an acknowledgment response accompanied by associated information when an instruction is received from the base station device 101. Here, the number of bits of the acknowledgment response to be transmitted changes depending on the presence or absence of associated information and the content of the associated information. For this reason, the terminal device 102 of this embodiment first specifies the first number of bits required to transmit the acknowledgment response, and specifies the second number of bits of the uplink control information (UCI) to be transmitted to the base station device 101 based on the first number of bits. Note that the UCI may include, for example, information indicating the state of the downlink channel (CSI, Channel State Information), and when specifying the second number of bits of the UCI, not only the first number of bits required to transmit the acknowledgment response but also all of such information to be transmitted to the base station device 101 is taken into consideration. Then, the terminal device 102 identifies a resource corresponding to the identified second number of bits based on the information associating the number of UCI bits and the resource notified from the base station device 101 as described above. Then, the terminal device 102 uses the resource to transmit the UCI including the acknowledgement response. That is, in this embodiment, when the number of UCI bits increases due to the transmission of the associated information, a resource to be used according to the increase in the number of bits is selected, and the UCI is transmitted using the resource.

On the other hand, the base station device 101 according to this embodiment knows in advance what kind of associated information will be included in the confirmation response to be received, and can therefore specify the first number of bits of the confirmation response and the second number of bits of the UCI, just like the terminal device 102. Therefore, after transmitting user data to the terminal device 102, the base station device 101 can specify in advance which resource will be used to receive the confirmation response to the user data (including associated information as necessary). Therefore, the base station device 101 receives the UCI including the confirmation response from the terminal device 102 using the specified resource. Note that when multiple resources are individually associated with the number of UCI bits, the base station device 101 may notify the terminal device 102 of information specifying which of the multiple resources should be used, in the same manner as in the conventional method.

The presence or absence of associated information and the contents of the associated information may be determined in advance, or the base station device 101 may notify the terminal device 102 of designation information that specifies the presence or absence of associated information and the contents of the associated information. The designation information may be individually transmitted to the terminal device 102 using an RRC (radio resource control) message, for example. According to this, when the designation information indicates that associated information is not to be transmitted, a confirmation response indicating only whether or not the reception of user data has been successful is transmitted, and the first bit number of UCI is specified. This specified first bit number is the same as the number of bits when only ACK/NACK is transmitted in the past, and the confirmation response to one confirmation response is one bit. On the other hand, when the designation information indicates that associated information is to be transmitted, the first bit number is specified based on the number of bits required to express the contents of the associated information specified by the designation information. For example, when an acknowledgement response accompanied by associated information can take any of four values, the number of bits required for one acknowledgement is two bits. Also, when an acknowledgement response accompanied by associated information can take any of eight values, the number of bits required for one acknowledgement is three bits. Once the number of bits required for one acknowledgement has been determined in this manner, it is possible to determine the first number of bits required to transmit the entire acknowledgement, for example, by multiplying it by the number of acknowledgements (the number of codewords).

The presence or absence of associated information and the contents of the associated information may be uniquely identified based on, for example, the service type. This is useful in cases where the target frame error rate is determined by the service type. In this case, the terminal device 102 can identify the presence or absence of associated information and the contents of the associated information according to the communication service provided to the terminal device 102, so there is no need to separately receive designation information from the base station device 101. The presence or absence of associated information and the contents of the associated information may be set separately for each of multiple codewords. For example, if the terminal device 102 is provided with multiple services, settings related to the associated information may be made separately for each of the multiple services. In this case, the presence or absence of associated information and the contents of the associated information for each service may be specified by the designation information, or may be uniquely identified corresponding to the service.

When resources for transmitting user data in the uplink are allocated to the terminal device 102, the terminal device 102 can transmit the acknowledgement using those resources. That is, if necessary, the acknowledgement with associated information may be multiplexed with the uplink user data and transmitted together with the user data.

As described above, in this embodiment, by enhancing the HARQ acknowledgement, the terminal device 102 can notify the base station device 101 of the reception status of user data in detail. This allows the base station device 101 to adaptively adjust the MCS, etc. used to transmit user data, regardless of whether the reception is successful. Therefore, it is possible to set up a radio link so that an appropriate MCS is used based on a small number of acknowledgements. Note that such an enhancement of the acknowledgement can be used in any system that uses acknowledgements such as HARQ and ARQ, and can also be applied to acknowledgements for user data transmitted from the terminal device 102. In addition, any wireless communication device other than the base station device 101 and the terminal device 102 can use this method.

(Device Configuration)
Next, an example of the hardware configuration of the base station device 101 and the terminal device 102 that execute the above-mentioned processing will be described with reference to FIG. 2. In one example, the base station device 101 and the terminal device 102 are configured to include a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205. The processor 201 is a computer configured to include one or more processing circuits such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and executes the overall processing of the base station device 101 and the terminal device 102 and each of the above-mentioned processing by reading and executing a program stored in the ROM 202 or the storage device 204. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the base station device 101 and the terminal device 102. The RAM 203 functions as a workspace when the processor 201 executes a program, and is a random access memory that stores temporary information. The storage device 204 is, for example, configured by a removable external storage device. 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 device 101 and the terminal device 102 may have multiple communication circuits. For example, the base station device 101 and the terminal device 102 may have separate communication circuits 205 for each of multiple available frequency bands. In addition, the base station device 101 and the terminal device 102 may have a common communication circuit 205 for at least a part of the multiple frequency bands. In addition, for example, the terminal device 102 may have not only the communication circuit 205 for cellular communication, but also a communication circuit 205 corresponding to other wireless communication standards such as wireless LAN.

Figure 3 is a diagram showing an example of the functional configuration of the terminal device 102. The terminal device 102 has, for example, an information acquisition unit 301, a bit number specification unit 302, a resource specification unit 303, a reception status determination unit 304, and an acknowledgement transmission unit 305 as its functions. Note that in Figure 3, only functions particularly related to this embodiment are shown, and other various functions that the terminal device 102 may have are omitted from the illustration. For example, the terminal device 102 naturally has other functions that a terminal device in a cellular communication system generally has. In addition, the functional blocks in Figure 3 are shown in schematic form, and each functional block may be realized by being integrated, or may be further subdivided. In addition, each function in Figure 3 may be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204, or may be realized, for example, by a processor present inside the communication circuit 205 executing a predetermined software. Note that the details of the processing performed by each functional unit will not be described in detail here, and only the rough functions will be outlined.

The information acquisition unit 301 acquires information that associates the number of bits of the uplink control information to be transmitted to the base station device 101 with the resource to which the uplink control information of the number of bits should be transmitted. The information acquisition unit 301 may acquire this information from the base station device 101, for example. Note that this information may be broadcast or may be transmitted individually to the terminal device 102. In addition, when multiple resources are associated with one bit number value, the information acquisition unit 301 may acquire predetermined information that specifies which of the resources should be used. For example, this predetermined information may be notified by downlink control information (DCI). In addition, the information acquisition unit 301 may acquire designation information that specifies, for example, whether or not to transmit an acknowledgment response accompanied by associated information, and, if an acknowledgment response accompanied by associated information should be transmitted, what content the acknowledgment response should be transmitted with. Note that, in the case where the presence or absence of associated information and the content of the associated information are determined in advance for each service type, the information acquisition unit 301 only needs to acquire information that specifies the service type, and does not need to acquire designation information.

The bit number determination unit 302 determines the number of bits in one acknowledgement based on the amount of information in the acknowledgement determined based on, for example, the designated information acquired by the information acquisition unit 301, and determines the number of bits required to transmit the acknowledgement by multiplying the number of bits by the number of codewords. The bit number determination unit 302 may determine the number of bits in the acknowledgement for each codeword individually, and determine the sum of the number of bits as the number of bits required to transmit the acknowledgement. The bit number determination unit 302 also determines the number of bits required to transmit the UCI by further considering other information to be transmitted in the UCI, such as the CSI value indicating the state of the downlink channel.

The resource identification unit 303 identifies resources associated with the number of bits identified by the number of bits identification unit 302 based on the information acquired by the information acquisition unit 301. The reception status determination unit 304 determines whether the decoding of user data received from the base station device 101 has been successful, and may also identify wireless quality information such as the number of iterations at the time of successful decoding when an iterative decoding method is used and the SINR of the received signal, for example. The acknowledgement transmission unit 305 generates an acknowledgement, including associated information as necessary, indicating the success or failure of reception and the reception status determined by the reception status determination unit 304, for example according to specified information, and transmits the acknowledgement using the resource identified by the resource identification unit 303, for example.

Figure 4 is a diagram showing an example of the functional configuration of the base station device 101. The base station device 101 has, for example, an information notification unit 401, a user data transmission unit 402, and an acknowledgment response reception unit 403 as its functions. Note that in Figure 4, only functions particularly related to this embodiment are shown, and various other functions that the base station device 101 may have are omitted from the illustration. For example, the base station device 101 naturally has other functions that a base station device in a cellular communication system generally has. Also, the functional blocks in Figure 4 are shown in schematic form, and each functional block may be realized by being integrated, or may be further subdivided. Also, each function in Figure 4 may be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204, or may be realized, for example, by a processor present inside the communication circuit 205 executing a predetermined software. Note that the details of the processing performed by each functional unit will not be described in detail here, and only the rough functions will be outlined.

The information notification unit 401 notifies the terminal device 102 of information associating the number of bits of the uplink control information to be transmitted by the terminal device 102 to the base station device 101 with the resource to which the uplink control information of the number of bits should be transmitted. This information may be broadcast or may be individually transmitted to the terminal device 102. When the information notification unit 401 notifies the terminal device 102 of information associating multiple resources with one bit number value, the information notification unit 401 may further notify the terminal device 102 of predetermined information specifying which of the multiple resources should be used. For example, this predetermined information may be notified by downlink control information (DCI). The information notification unit 401 may also notify the terminal device 102 of designation information specifying whether or not to transmit an acknowledgment response accompanied by associated information, and, if an acknowledgment response accompanied by associated information should be transmitted, what content the acknowledgment response should be transmitted with. When the presence or absence of associated information and the content of the associated information are determined in advance for each service type, the information notification unit 401 only needs to notify information specifying the service type, and does not need to notify the designation information.

The user data transmission unit 402 transmits user data to the terminal device 102. This user data transmission is performed by a conventional method, and will not be described in detail here. The acknowledgement reception unit 403 identifies the second number of bits of the UCI to be transmitted from the terminal device 102, for example, based on the first number of bits of the acknowledgement that is identified in response to the specified information notified to the terminal device 102. The acknowledgement reception unit 403 then executes a reception process for the UCI including the acknowledgement from the terminal device 102 in a resource associated with the identified second number of bits of the UCI (in the case where multiple resources are associated, a further specified resource among them).

(Processing flow)
Next, an example of the flow of processing executed by the base station device 101 and the terminal device 102 according to the present embodiment will be outlined with reference to Fig. 5. Note that this is just an example, and the base station device 101 and the terminal device 102 may execute various types of processing as exemplified above.

In this process, the base station device 101 first transmits information indicating the number of UCI bits and the resources to be used when transmitting the UCI of that number of bits to the terminal device 102, for example, via a broadcast SIB (System Information Block) or the like (S501). This information may be notified to the terminal device 102 individually, for example, using an RRC message or the like. The base station device 101 also notifies the terminal device 102 individually, for example, using an RRC message or the like (S502). The confirmation response configuration information includes the presence or absence of associated information, and if associated information is included, the content of the associated information (for example, information that associates the bit string indicated by the confirmation response with the information to be transmitted). After that, the base station device 101 transmits user data to the terminal device 102 (S503).

When the terminal device 102 receives user data, it judges the reception status of the user data (S504). Here, the terminal device 102 judges whether the reception of the user data (decoding of the codeword) was successful or not, and when transmitting an acknowledgment response accompanied by associated information, it judges the wireless quality and the number of iterations of the decoding process by the iterative decoding method, etc., according to the contents of the associated information. In addition, the terminal device 102 specifies the number of bits required to transmit the acknowledgment response based on whether the acknowledgment response is accompanied by associated information, the number of bits required to express the contents of the associated information, the number of codewords received, etc. (S505). Furthermore, the terminal device 102 specifies the number of bits required to transmit the uplink control information (UCI) taking into consideration other information to be transmitted together with the acknowledgment response, such as CSI (S506). Note that the order of the processes of S503 and S504 and the processes of S505 and S506 may be reversed. That is, the terminal device 102 may specify the number of bits of the acknowledgement (and the number of bits of the UCI) in advance, for example, based on the acknowledgement setting and the number of codewords, and then receive user data and determine the reception status. These processes may also be performed in parallel. The terminal device 102 refers to the information received in S501, specifies a resource corresponding to the number of bits of the UCI specified in S506 (S507), and uses the resource to transmit the UCI including the acknowledgement (S508).

In this manner, in this embodiment, by configuring the confirmation response with accompanying information, the base station device 101 can recognize not only whether the user data was received successfully, but also, for example, under what circumstances the user data was received successfully/unsuccessfully. This enables the base station device 101 to appropriately control the wireless link with the terminal device 102 under various circumstances.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the invention.

Claims (14)

A terminal device,
an acquisition means for acquiring, from the base station device, information associating a number of bits of uplink control information to be transmitted to the base station device with a resource to which the uplink control information of the number of bits is to be transmitted, and information indicating a decision on whether or not to transmit associated information regarding a reception status of the user data, the information being determined based on a service quality associated with the user data;
a determination means for determining a second number of bits of uplink control information to be transmitted to the base station device based on information indicating the determination and a first number of bits required for transmitting an acknowledgment including the associated information;
a transmitting means for transmitting uplink control information including the acknowledgement to the base station device by using the resource associated with the second number of bits;
A terminal device comprising: the acquiring means acquires, from the base station device, designation information for designating whether or not the associated information is to be transmitted and the contents of the associated information;
the specifying means, when the designation information indicates that the associated information is not to be transmitted, transmits the confirmation response indicating only whether or not the reception of the user data has been successful, and, when the designation information indicates that the associated information is to be transmitted, specifies the first number of bits based on the number of bits necessary to express the content of the associated information designated by the designation information.
2. The terminal device according to claim 1 . the specifying means specifies the first number of bits based on a value obtained by multiplying the number of codewords transmitted from the base station device as the user data and for which the acknowledgment should be transmitted by the number of bits of one acknowledgment.
3. The terminal device according to claim 1 or 2. the acquiring means acquires from the base station device the information associating a plurality of resources with one or more values of the number of bits individually, and predetermined information designating which of the plurality of resources should be used;
the transmitting means transmits uplink control information including the acknowledgment response to the base station apparatus, using a resource designated by the predetermined information among the plurality of resources associated with the second number of bits.
4. The terminal device according to claim 1, wherein the first and second terminals are connected to each other. The method further comprises: decoding means for decoding the user data using an iterative decoding method for repeatedly decoding one codeword;
The confirmation response accompanied by the associated information indicates either a value indicating failure in reception of the user data or a value indicating the number of iterations when the reception of the user data is successful and the reception is determined to be successful in the iterative decoding method.
5. The terminal device according to claim 1, wherein the first and second terminals are connected to each other. The method further comprises: measuring means for measuring a radio quality when receiving the user data;
the confirmation response accompanied by the associated information further includes a value indicating the wireless quality when the confirmation response indicates at least one of failure and success of reception of the user data.
6. The terminal device according to claim 1, wherein the first and second terminals are connected to each other. A base station device,
A determination means for determining whether or not to transmit associated information regarding a receiving state of the user data based on a service quality associated with the user data;
A notification means for notifying the terminal device of information associating a number of bits of uplink control information to be received from the terminal device with a resource to which the uplink control information of the number of bits is to be transmitted , and information indicating the determination ;
A transmitting means for transmitting user data to the terminal device;
a receiving means for receiving an acknowledgment accompanied by associated information on a reception status of the user data in the terminal device, the receiving means receiving the acknowledgment in the resource associated with a second number of bits specified as a number of bits required for transmitting uplink control information based on the information indicating the decision and a first number of bits required for transmitting the acknowledgment;
A base station device comprising: the notification means notifies the terminal device of designation information for designating whether or not the associated information is to be transmitted and the contents of the associated information;
When the designation information indicates that the associated information is not to be transmitted, the confirmation response indicating only whether or not the reception of the user data has been successful is transmitted, and when the designation information indicates that the associated information is to be transmitted, the first number of bits is specified based on the number of bits required to express the content of the associated information designated by the designation information.
The base station device according to claim 7 . the first number of bits is specified based on a value obtained by multiplying the number of code words to be transmitted as the user data to the terminal device and for which the acknowledgement should be received by the number of bits of one acknowledgement;
9. The base station device according to claim 7 or 8. the notification means notifies the terminal device of the information associating a plurality of resources with each of a plurality of values indicating the number of bits, and predetermined information designating which of the plurality of resources should be used;
the receiving means receives uplink control information including the acknowledgment response in a resource designated by the predetermined information among the plurality of resources associated with the second number of bits.
The base station device according to any one of claims 7 to 9. A communication method performed by a terminal device, comprising:
acquiring, from the base station device, information associating a number of bits of uplink control information to be transmitted to the base station device with a resource to transmit the uplink control information of the number of bits , and information indicating a decision on whether or not to transmit associated information regarding a reception status of the user data, the associated information being determined based on a service quality associated with the user data ;
determining a second number of bits of uplink control information to be transmitted to the base station device based on information indicating the determination and a first number of bits required for transmitting an acknowledgment including the associated information;
transmitting uplink control information including the acknowledgement to the base station device using the resource associated with the second number of bits;
A communication method comprising: A communication method performed by a base station device, comprising:
determining whether or not to transmit associated information regarding a reception status of the user data based on a service quality associated with the user data;
notifying the terminal device of information associating a number of bits of uplink control information to be received from the terminal device with a resource to which the uplink control information of the number of bits is to be transmitted , and information indicating the determination ;
transmitting user data to the terminal device;
receiving an acknowledgment accompanied by associated information regarding a reception status of the user data in the terminal device, wherein the acknowledgment is received in the resource associated with a second number of bits specified as a number of bits required for transmitting uplink control information based on information indicating the determination and a first number of bits required for transmitting the acknowledgment;
A communication method comprising: A computer installed in the terminal device
obtain, from the base station device, information associating a number of bits of uplink control information to be transmitted to the base station device with a resource to transmit the uplink control information of the number of bits , and information indicating a decision on whether or not to transmit associated information regarding a reception status of the user data, the information being determined based on a service quality associated with the user data ;
determining a second number of bits of uplink control information to be transmitted to the base station device based on information indicating the determination and a first number of bits required for transmitting an acknowledgment including the associated information;
transmitting uplink control information including the acknowledgement to the base station device using the resource associated with the second number of bits;
Program for. A computer installed in the base station device
determining whether or not to transmit associated information regarding a reception status of the user data based on the service quality associated with the user data;
notifying the terminal device of information associating a number of bits of uplink control information to be received from the terminal device with a resource to which the uplink control information of the number of bits is to be transmitted , and information indicating the determination ;
causing the terminal device to transmit user data;
receiving an acknowledgment accompanied by associated information on a reception status of the user data in the terminal device, wherein the acknowledgment is received in the resource associated with a second number of bits specified as a number of bits required for transmitting uplink control information based on information indicating the decision and a first number of bits required for transmitting the acknowledgment;
Program for.

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