Terminal device, base station device, and communication method

Abstract

This terminal device comprises a MAC layer processing unit that recognizes a service period that is set in a TWT, and a transmission unit that performs transmission of a frame within the TWT. During carrier sensing that is performed prior to the transmission of the frame, the maximum value of a contention window size is changed on the basis of a condition pertaining to the service period.

Description

Terminal device, base station device, and communication method

[0001] The present invention relates to a terminal device, a base station device, and a communication method. This application claims priority to Japanese Patent Application No. 2021-203210, filed on December 15, 2021, the contents of which are incorporated herein by reference.

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is considering the formulation of IEEE802.11be, which is positioned as a successor standard to the IEEE802.11 standard (Non-Patent Document 1).

[0003] "Proposed 802.11be Functional Requirements", Huawei Technologies, 2nd February, 2019.

[0004] One aspect of the present invention provides a terminal device, a base station device, and a communication method used in the terminal device that perform communication efficiently.

[0005] (1) A first aspect of the present invention is a terminal device comprising a MAC layer processing unit that recognizes a service period set in a TWT, and a transmitting unit that transmits frames within the TWT, and changes the maximum contention window size in a carrier sense performed prior to transmitting the frames based on conditions related to the service period.

[0006] (2) A second aspect of the present invention is a base station device comprising a MAC layer processing unit that recognizes a service period set in a TWT, and a transmitting unit that transmits frames within the TWT, and changes the maximum contention window size in a carrier sense performed prior to transmitting the frames based on conditions related to the service period.

[0007] (3) A third aspect of the present invention is a communication method used in a terminal device, comprising the steps of recognizing a service period set in a TWT and transmitting a frame within the TWT, and changing the maximum contention window size in a carrier sense performed prior to transmitting the frame based on conditions related to the service period.

[0008] According to one aspect of the present invention, a terminal device can perform communication efficiently, and a base station device can perform communication efficiently.

[0009] Fig. 1 is a conceptual diagram of a wireless communication system 9 according to one aspect of the present embodiment. Fig. 2 is a schematic block diagram showing a configuration example of a base station device 3 according to one aspect of the present embodiment. Fig. 3 is a schematic block diagram showing a configuration example of a terminal device 1 according to one aspect of the present embodiment. Fig. 4 is a diagram showing an example of TWT setting in a wireless communication system #9 according to one aspect of the present embodiment. Fig. 5 is a diagram showing an example of a counting procedure according to one aspect of the present embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described.

[0011] floor(C) may be a floor function for real number C. For example, floor(C) may be a function that outputs the largest integer not exceeding real number C. ceil(D) may be a ceiling function for real number D. For example, ceil(D) may be a function that outputs the smallest integer not below real number D. mod(E,F) may be a function that outputs the remainder when E is divided by F. mod(E,F) may be a function that outputs a value corresponding to the remainder when E is divided by F. exp(G) = e^G, where e is Napier's constant. H^I denotes H to the Ith power. max(J,K) is a function that outputs the maximum value of J and K. Here, max(J,K) is a function that outputs J or K when J and K are equal. min(L,M) is a function that outputs the maximum value of L and M. Here, min(L,M) is a function that outputs L or M when L and M are equal. round(N) is a function that outputs the integer value closest to N. "·" indicates multiplication.

[0012] Fig. 1 is a conceptual diagram of a wireless communication system 9 according to one aspect of the present embodiment. In Fig. 1, the wireless communication system includes terminal devices 1A to 1C and a base station device 3 (AP#3: Access Point#3). Hereinafter, the terminal devices 1A to 1C will be collectively referred to as terminal device 1 (STA#1: Station#1), and the terminal device that communicates with base station device 3 will also be referred to as terminal device 1 (STA#1: Station#1).

[0013] Unless otherwise specified, the following description will be given using an example in which a frame is transmitted from the terminal device 1 to the base station device 3, but various aspects of the present embodiment may also be applied to the case in which a frame is transmitted from the base station device 3 to the terminal device 1. Here, the terminal device 1 may be referred to as a Non-AP STA. Also, the base station device may be referred to as an AP STA.

[0014] In the wireless communication system 9, the terminal device 1 and the base station device 3 may communicate using CP-OFDM (Cyclic Prefix-Orthogonal Frequency Division Multiplex). The wireless communication system 9 is also referred to as BSS (Basic Service Set) #9.

[0015] As shown in Fig. 1, the base station device 3 may be configured with one transceiver device (or transmission point, transmission device, reception point, reception device, transceiver point). On the other hand, in some cases, the base station device 3 may be configured to include multiple transceivers. When the base station device 3 is configured with multiple transceivers, each of the multiple transceivers may be located in a different geographical location.

[0016] 2 is a schematic block diagram showing an example of the configuration of a base station device 3 according to one aspect of the present embodiment. As shown in FIG. 2, the base station device 3 includes a physical layer processing unit (radio transmitting / receiving unit) 30 and a higher layer processing unit 34. The physical layer processing unit 30 includes an antenna unit 31, an RF (Radio Frequency) processing unit 32, and part or all of a baseband processing unit 33.

[0017] The physical layer processing unit 30 performs physical layer processing. Here, the physical layer processing may include processing for generating an OFDM baseband signal and processing for detecting a frame. A frame is also called a data unit.

[0018] The upper layer processing unit 34 performs processing for the MAC (Medium Access Control) layer, including a carrier sense mechanism.

[0019] The physical layer processing unit 30 may perform some or all of modulation processing, encoding processing, and transmission processing. The physical layer processing unit 30 may generate a frame based on some or all of encoding processing, modulation processing, and baseband signal generation processing for an information bit sequence to be transmitted in the frame.

[0020] The physical layer processing unit 30 may perform one or both of demodulation and decoding processing, and may perform detection based on the demodulation and decoding processing of the received frame.

[0021] The physical layer processing unit 30 may perform carrier sensing prior to transmitting a frame.

[0022] The RF unit 32 may convert the signal received via the antenna unit 31 into a baseband signal and remove unnecessary frequency components. The RF unit 32 outputs the baseband signal to the baseband unit 33.

[0023] The baseband unit 33 may digitize the baseband signal input from the RF unit 32. The baseband unit 33 may remove a portion corresponding to a cyclic prefix (CP) from the digitized baseband signal. The baseband unit 33 may perform a fast Fourier transform (FFT) on the baseband signal from which the CP has been removed to extract a frequency domain signal.

[0024] The baseband unit 33 may generate a baseband signal by performing an Inverse Fast Fourier Transform (IFFT) on the physical signal. The baseband unit 33 may add a CP to the generated baseband signal. The baseband unit 33 may convert the baseband signal to which the CP has been added into an analog signal. The baseband unit 33 may output the analog baseband signal to the RF unit 32.

[0025] The RF unit 32 may remove unnecessary frequency components from the baseband signal input from the baseband unit 33. The RF unit 32 may up-convert the baseband signal to a carrier frequency to generate an RF signal. The RF unit 32 may transmit the RF signal via the antenna unit 31. The RF unit 32 may also have a function of controlling transmission power.

[0026] 3 is a schematic block diagram showing an example of the configuration of a terminal device 1 according to one aspect of the present embodiment. As shown in FIG. 3, the terminal device 1 includes a physical layer processing unit (radio transmitting / receiving unit) 10 and part or all of an upper layer processing unit 14. The radio transmitting / receiving unit 10 includes an antenna unit 11, an RF unit 12, and part or all of a baseband unit 13.

[0027] The physical layer processing unit 10 performs physical layer processing, which may include generation of an OFDM baseband signal and frame detection.

[0028] The upper layer processing unit 14 performs processing for the MAC (Medium Access Control) layer, including a carrier sense mechanism.

[0029] The physical layer processing unit 10 may perform some or all of modulation processing, encoding processing, and transmission processing. The physical layer processing unit 30 may generate frames based on some or all of encoding processing, modulation processing, and baseband signal generation processing for an information bit sequence to be transmitted in a frame.

[0030] The physical layer processing unit 10 may perform one or both of demodulation and decoding processing, and may perform detection based on the demodulation and decoding processing of the received frame.

[0031] The physical layer processing unit 10 may perform carrier sensing prior to transmitting a frame.

[0032] The physical layer processing unit 10 may perform some or all of modulation processing, encoding processing, and transmission processing. The physical layer processing unit 10 may generate a physical signal based on some or all of encoding processing, modulation processing, and baseband signal generation processing for an information bit sequence to be transmitted in a frame.

[0033] The physical layer processing unit 10 may perform one or both of a demodulation process and a decoding process.

[0034] The physical layer processing unit 10 may perform carrier sensing prior to transmitting a frame.

[0035] The RF unit 12 may convert the signal received via the antenna unit 11 into a baseband signal and remove unnecessary frequency components from it. The RF unit 12 outputs the baseband signal to the baseband unit 13.

[0036] The baseband unit 13 may digitize the baseband signal input from the RF unit 12. The baseband unit 13 may remove a portion corresponding to a cyclic prefix (CP) from the digitized baseband signal. The baseband unit 13 may perform a fast Fourier transform (FFT) on the baseband signal from which the CP has been removed to extract a frequency domain signal.

[0037] The baseband unit 13 may generate a baseband signal by performing an Inverse Fast Fourier Transform (IFFT) on the physical signal. The baseband unit 13 may add a CP to the generated baseband signal. The baseband unit 13 may convert the baseband signal to which the CP has been added into an analog signal. The baseband unit 13 may output the analog baseband signal to the RF unit 12.

[0038] The RF unit 12 may remove unnecessary frequency components from the baseband signal input from the baseband unit 13. The RF unit 12 may up-convert the baseband signal to a carrier frequency to generate an RF signal. The RF unit 12 may transmit the RF signal via the antenna unit 31. The RF unit 12 may also have a function of controlling transmission power.

[0039] Target Wake Time (TWT) may be used to manage radio resources in the wireless communication system #9, for example, to reduce contention within the wireless communication system #9.

[0040] 4 is a diagram showing an example of TWT settings in a wireless communication system #9 according to one aspect of the present embodiment. In FIG. 4, the horizontal axis represents time. Also, reference numeral 4000 denotes a frame including information indicating TWT settings. For example, frame 4000 may be a beacon frame.

[0041] 4, 4010 is a TWT. The TWT 4010 is set as a period in the time domain. For example, another TWT may start at the end of the TWT 4010. For example, the TWT may be set periodically.

[0042] 4, reference numeral 4011 denotes a service period, and reference numeral 4012 denotes a period of the TWT 4010 that is not a service period.

[0043] For example, the frame 4000 may include information indicating the length of the TWT and information indicating the length of the service period.

[0044] For example, the terminal device 1 may set the TWT 4010 based on information indicating the setting of the TWT 4010, which is included in the frame 4000. For example, the upper layer processing unit 14 may implement a carrier sense mechanism prior to transmitting the frame 0.

[0045] The carrier sense mechanism may be configured to include at least one or both of an inter-frame space (IFS) related process and a counting procedure.

[0046] After the carrier sense mechanism is implemented, the physical layer processing unit 10 may transmit the frame.

[0047] The IFS procedure may be used to perform carrier sensing for different periods set for each IFS type and determine whether the medium is idle or busy. That is, in the IFS procedure, the physical layer processing unit 10 may perform carrier sensing and determine whether the medium is idle or busy. Carrier sensing is a type of monitoring used by the physical layer processing unit 10. For example, detection of a certain preamble may be performed in carrier sensing. Here, the preamble monitored in carrier sensing may be a Short Training Sequence (STF). The STF is a preamble added to the beginning of a frame transmitted by the terminal device 1. For example, based on the detection of the certain preamble by carrier sensing, the physical layer processing unit 10 may report a busy state to the upper layer processing unit 14. Alternatively, based on the absence of detection of the certain preamble by carrier sensing, the physical layer processing unit 10 may report an idle state to the upper layer processing unit 14.

[0048] For example, the amount of detected energy may be monitored during carrier sensing. When the amount of energy is detected during carrier sensing, the amount of detected energy may be compared with a threshold value to determine whether the medium is idle or busy. For example, during carrier sensing, the physical layer processing unit 10 may report "idle" to the upper layer processing unit 14 based on the amount of energy measured on the medium being greater than the threshold value. Alternatively, during carrier sensing, the physical layer processing unit 10 may report "busy" to the upper layer processing unit 14 based on the amount of energy measured on the medium being less than the threshold value. Alternatively, during carrier sensing, if the amount of energy measured on the medium is equal to the threshold value, the physical layer processing unit 10 may report either "busy" or "idle" to the upper layer processing unit 14.

[0049] An SIFS is a type of IFS. For example, an SIFS may be configured to be 16 microseconds. Here, the time length of an SIFS is also referred to as aSIFSTime.

[0050] A DIFS is a type of IFS. For example, a DIFS may have a time length calculated as aSIFSTime+2*aSlotTime, where aSlotTime is the time length constituting a slot used for carrier sensing. For example, the time length constituting a slot may be 9 microseconds.

[0051] AIFS is a type of IFS. For example, DIFS may be composed of a time length calculated as aSIFSTime+AIFSN(AC)*aSlotTime, where AIFSN(AC) is the value of AIFSN when the access category is AC. The value of AIFSN may differ for each access category. Details of AIFSN will be described later.

[0052] In the carrier sense mechanism, if SIFS is set prior to frame transmission, the physical layer processing unit 10 does not need to perform carrier sense.

[0053] 5 is a diagram illustrating an example of a counting procedure according to one aspect of the present embodiment. The counting procedure is also called a random backoff procedure. The counting procedure includes at least some or all of steps A1 to A6. Step A1 increments the value of counter N to N ｉｎｉｔ Here, N ｉｎｉｔ is a value randomly (or pseudo-randomly) selected from integer values ​​in the range from 0 to CW(AC), and CWp is the contention window size (CWS) for AC.

[0054] In step A2, it is determined whether the value of counter N is 0. Step A2 includes an operation of completing (or terminating) the carrier sense mechanism if counter N is 0. Step A2 includes an operation of proceeding to step A3 if counter N is different from 0. Here, True in FIG. 5 corresponds to the evaluation formula being true in a step including an operation of determining the evaluation formula. False corresponds to the evaluation formula being false in a step including an operation of determining the evaluation formula. In step A2, the evaluation formula corresponds to counter N=0.

[0055] For example, Step A3 may include a step of decrementing the value of counter N. Decrementing the value of counter N may decrease the value of counter N by 1. In other words, decrementing the value of counter N may set the value of counter N to N-1.

[0056] For example, step A3 may include a step of decrementing the value of the counter N when N>0. Also, step A3 may include a step of decrementing the value of the counter N when the base station device 3 or the terminal device 1 selects to decrement the counter N. Also, step A3 may include a step of decrementing the value of the counter N when N>0 and the base station device 3 or the terminal device 1 selects to decrement the counter N.

[0057] For example, step A4 may include an operation of performing carrier sensing of the medium in slot d and proceeding to step A2 if slot d is idle. Step A4 may also include an operation of performing carrier sensing in slot d and proceeding to step A2 if slot d is determined to be idle by carrier sensing. Step A4 may also include an operation of performing carrier sensing in slot d and proceeding to step A5 if slot d is busy. Step A4 may also include an operation of proceeding to step A5 if slot d is determined to be busy by carrier sensing. Here, slot d may be a slot that is the next slot period of an LBT slot period that has already been carrier sensed in the counting procedure. In step A4, the evaluation formula may correspond to slot d being idle.

[0058] Step A5 includes the operation of performing carrier sensing until the processing related to the IFS detects that the medium is busy.

[0059] Step A6 includes an operation of proceeding to step A5 if the processing related to the IFS detects that the medium is busy, and an operation of proceeding to step A2 if the processing related to the IFS detects that the medium is idle.

[0060] CWmin(AC) indicates the minimum value of the range of possible values ​​of the contention window size CWp for access category AC. CWmax(AC) indicates the maximum value of the range of possible values ​​of the contention window size CWp for access category AC. The contention window size CWp for access category AC is also referred to as CWp.

[0061] The value of the counter N used in the carrier sense mechanism may be managed for each access category. For example, the terminal device 1 may manage multiple access categories independently. For example, the terminal device 1 may perform a random backoff procedure independently for each of the multiple access categories.

[0062] For example, the terminal device 1 may manage a counter N for each of a plurality of access categories. Here, the value of the counter N for the access category AC is also referred to as counter N(AC).

[0063] When a frame related to access category AC is transmitted, the CWp is managed by the base station device 3 or the terminal device 1, and the CWp is adjusted before step A1 of the counting procedure (the CWp adjustment procedure is performed).

[0064] A plurality of access categories may be defined. For example, CWmin(AC_BK) = aCWmin, CWmax(AC_BK) = aCWmax, and AIFSN(AC_BK) = 9. Alternatively, CWmin(AC_BE) = aCWmin, CWmax(AC_BE) = aCWmax, and AIFSN(AC_BE) = 6. Alternatively, CWmin(AC_VI) = (aCWmin+1) / 2-1, CWmax(AC_VI) = aCWmin, and AIFSN(AC_VI) = 3. Alternatively, CWmin(AC_VO) = ​​(aCWmin+1) / 4-1, CWmax(AC_VO) = ​​(aCWmin+1) / 2-1, and AIFSN(AC_VO) = ​​2.

[0065] In this way, various parameter values ​​used in the carrier sensing mechanism may be set differently for each access category. An access control method in which the carrier sensing mechanism is performed for each access category is also called Enhanced Distributed Channel Access (EDCA).

[0066] When the terminal device 1 transmits a frame in the TWT 4010, a carrier sense mechanism is implemented prior to transmitting the frame. Here, the terminal device 1 may recognize the service period 4011 and implement the carrier sense mechanism.

[0067] For example, the terminal device 1 may determine various parameters used in the carrier sense mechanism based on its recognition of the service period 4011 and the access category associated with the frame.

[0068] Here, the terminal device 1 may determine various parameters used in the carrier sense mechanism based on whether the conditions regarding the service period 4011 are met and the access category associated with the frame.

[0069] For example, the condition related to the service period 4011 may be any one of the following conditions 1 to 6: Condition 1) The frame that the terminal device 1 intends to transmit is included in the service period 4011; Condition 2) The timing at which it is decided to transmit the frame is included in the service period 4011; and Condition 3) The time after a predetermined period has elapsed since it is decided to transmit the frame is included in the service period 4011.

[0070] For example, in condition 3, the predetermined period may be a period corresponding to SHIS. For example, in condition 3, the predetermined period may be a period corresponding to PIFS. For example, in condition 3, the predetermined period may be a period corresponding to DIFS. For example, in condition 3, the predetermined period may be a period corresponding to AIFS, which corresponds to the access category with the highest priority among the access categories.

[0071] For example, the AIFSN may be determined based on whether the conditions regarding the service period 4011 are satisfied and the value of the access category associated with the frame. Here, determining the AIFSN value to be 2 may be interpreted as using DIFS.

[0072] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_BK, then AIFSN(AC_BK)=9.

[0073] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BK, then AIFSN(AC_BK)=2.

[0074] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_BE, then AIFSN(AC_BE)=6.

[0075] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BE, then AIFSN(AC_BE)=3.

[0076] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VI, then AIFSN(AC_VI)=3.

[0077] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_VO, then AIFSN(AC_VO)=2.

[0078] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VO, then AIFSN(AC_VO)=2.

[0079] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_VI, then AIFSN(AC_VI)=2.

[0080] For example, CWmin may be determined based on whether the conditions for the service period 4011 are satisfied and the value of the access category associated with the frame. For example, if the conditions for the service period 4011 are satisfied and the access category associated with the frame is AC_BK, CWmin(AC_BK) = aCWmin.

[0081] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BK, then CWmin(AC_BK) = aCWmin.

[0082] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_BE, then CWmin(AC_BE) = aCWmin.

[0083] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BE, then CWmin(AC_BE) = aCWmin.

[0084] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VI, then CWmin(AC_VI)=(aCWmin+1) / 2-1.

[0085] For example, if the conditions regarding the service period 4011 are not met and the access category associated with the frame is AC_VO, then CWmin(AC_VO)=aCWmin.

[0086] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VO, then CWmin(AC_VO)=(aCWmin+1) / 4-1.

[0087] For example, if the conditions regarding the service period 4011 are not met and the access category associated with the frame is AC_VI, then CWmin(AC_VI)=aCWmin.

[0088] For example, when a condition related to the service period 4011 is satisfied, CWmax may be determined based on the value of the access category associated with the frame. For example, when the terminal device 1 transmits a frame in the service period 4011 and the access category associated with the frame is AC_BK, CWmax(AC_BK) = aCWmax may be satisfied.

[0089] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BK, then CWmax (AC_BK) = aCWmax.

[0090] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_BE, then CWmax (AC_BE) = aCWmin.

[0091] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_BE, then CWmax (AC_BE) = aCWmin.

[0092] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VI, then CWmax(AC_VI)=(aCWmin+1) / 2-1.

[0093] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_VO, then CWmax (AC_VO) may equal aCWmin.

[0094] For example, if the conditions for service period 4011 are met and the access category associated with the frame is AC_VO, then CWmax (AC_VO)=(aCWmin+1) / 4-1.

[0095] For example, if the conditions for service period 4011 are not met and the access category associated with the frame is AC_VI, then CWmax(AC_VI)=(aCWmin+1) / 2-1.

[0096] For example, the access category to which the frame belongs may be determined based on whether or not a condition regarding the service period 4011 is satisfied.

[0097] For example, when the conditions regarding the service period 4011 are met and the type of the frame satisfies a first requirement, the terminal device 1 may determine that the access category associated with the frame is AC_BK_X. For example, the first requirement may be non-time-critical, loss-insensitive, and have a lower priority than best effort.

[0098] For example, AIFSN(AC_BK_X) may be set to a different value than AIFSN(AC_BK), CWmin(AC_BK_X) may be set to a different value than CWmin(AC_BK), and CWmax(AC_BK_X) may be set to a different value than CWmax(AC_BK).

[0099] For example, if the conditions regarding the service period 4011 are not met and the type of the frame satisfies the first requirement, the terminal device 1 may determine that the access category associated with the frame is AC_BK.

[0100] For example, when the conditions related to the service period 4011 are met and the type of the frame satisfies a second requirement, the terminal device 1 may determine the access category associated with the frame to be AC_BE_X. For example, the second requirement may be non-time-critical and loss insensitive. The second requirement is also referred to as best effort.

[0101] For example, AIFSN(AC_BE_X) may be set to a different value than AIFSN(AC_BE), CWmin(AC_BE_X) may be set to a different value than CWmin(AC_BE), and CWmax(AC_BE_X) may be set to a different value than CWmax(AC_BE).

[0102] For example, if the conditions regarding the service period 4011 are not met and the type of the frame satisfies the second requirement, the terminal device 1 may determine that the access category associated with the frame is AC_BE.

[0103] For example, when the conditions regarding the service period 4011 are met and the type of the frame satisfies a third requirement, the terminal device 1 may determine the access category associated with the frame to be AC_VI_X. For example, the third requirement may be a time-critical condition, a loss-sensitive condition, and a requirement that the delay be 100 ms or less.

[0104] For example, AIFSN(AC_VI_X) may be set to a different value than AIFSN(AC_VI), CWmin(AC_VI_X) may be set to a different value than CWmin(AC_VI), and CWmax(AC_VI_X) may be set to a different value than CWmax(AC_VI).

[0105] For example, if the conditions regarding the service period 4011 are not met and the type of the frame satisfies the third requirement, the terminal device 1 may determine that the access category associated with the frame is AC_VI.

[0106] For example, when the conditions regarding the service period 4011 are met and the type of the frame satisfies a fourth requirement, the terminal device 1 may determine that the access category associated with the frame is AC_VO_X. For example, the fourth requirement may be a time-critical condition, a loss-sensitive condition, and a condition requiring a delay of 10 ms or less.

[0107] For example, AIFSN(AC_VO_X) may be set to a different value than AIFSN(AC_VO), CWmin(AC_VO_X) may be set to a different value than CWmin(AC_VO), and CWmax(AC_VO_X) may be set to a different value than CWmax(AC_VO).

[0108] For example, if the conditions regarding the service period 4011 are not met and the type of the frame satisfies the fourth requirement, the terminal device 1 may determine that the access category associated with the frame is AC_VO.

[0109] For example, the access category set to which the frame belongs may be determined based on whether or not a condition regarding the service period 4011 is satisfied.

[0110] For example, the conditions regarding the service period 4011 may be satisfied, and the terminal device 1 may select the first access category set. For example, the first access category set may include some or all of AC_BK_X, AC_BE_X, AC_VI_X, and AC_VO_X.

[0111] For example, the conditions regarding the service period 4011 may not be satisfied, and the terminal device 1 may select the second access category set. For example, the second access category set may include some or all of AC_BK, AC_BE, AC_VI, and AC_VO.

[0112] The terminal device 1 may select one access category from one or more access categories included in the selected access category set based on the requirements corresponding to the frame to be transmitted.

[0113] Various aspects of the device according to one aspect of this embodiment will be described below.

[0114] (1) In order to achieve the above object, aspects of the present invention take the following measures: That is, a first aspect of the present invention is a terminal device, comprising a MAC layer processing unit that recognizes a service period set in a TWT, and a transmitting unit that transmits frames within the TWT, and changes the maximum contention window size in a carrier sense that is performed prior to transmitting the frames based on conditions related to the service period.

[0115] (2) Also, in the first aspect of the present invention, if the frame belongs to a first access category and transmission of the frame is intended to occur within the service period, the maximum value is set to a first value; if the frame belongs to the first access category and transmission of the frame is not intended to occur within the service period, the maximum value is set to a second value; and if the frame belongs to a second access category, the maximum value is set to the second value.

[0116] (3) In the first aspect of the present invention, the access category associated with the frame is determined based on a condition related to the service period.

[0117] (4) A second aspect of the present invention is a base station device comprising a MAC layer processing unit that recognizes a service period set in a TWT, and a transmitting unit that transmits frames within the TWT, and changes the maximum contention window size in a carrier sense performed prior to transmitting the frames based on conditions related to the service period.

[0118] (5) Also, in a second aspect of the present invention, if the frame belongs to a first access category and transmission of the frame is intended to occur within the service period, the maximum value is set to a first value; if the frame belongs to the first access category and transmission of the frame is not intended to occur within the service period, the maximum value is set to a second value; and if the frame belongs to a second access category, the maximum value is set to the second value.

[0119] (6) In the second aspect of the present invention, the access category associated with the frame is determined based on a condition related to the service period.

[0120] The programs running on the base station device 3 and terminal device 1 according to one aspect of the present invention may be programs (programs that cause a computer to function) that control a CPU (Central Processing Unit) or the like so as to realize the functions of the above-described embodiment according to one aspect of the present invention. Information handled by these devices is temporarily stored in RAM (Random Access Memory) during processing, and then stored in various ROMs such as Flash ROM (Read Only Memory) or HDD (Hard Disk Drive), and is read, modified, and written by the CPU as needed.

[0121] Note that a part of the terminal device 1 and the base station device 3 in the above-described embodiment may be realized by a computer. In this case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize the function.

[0122] The term "computer system" used here refers to a computer system built into the terminal device 1 or base station device 3, and includes hardware such as an OS and peripheral devices. Also, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into the computer system.

[0123] Furthermore, the term "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a fixed period of time, such as volatile memory within a computer system that serves as a server or client in such a case. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already stored in the computer system.

[0124] Furthermore, the base station device 3 in the above-described embodiment can also be realized as a collection (device group) consisting of multiple devices. Each of the devices constituting the device group may have some or all of the functions or functional blocks of the base station device 3 according to the above-described embodiment. It is sufficient for the device group to have all of the functions or functional blocks of the base station device 3. Furthermore, the terminal device 1 according to the above-described embodiment can also communicate with the base station device as a collection.

[0125] Furthermore, the base station device 3 in the above-described embodiment may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network) and / or an NG-RAN (NextGen RAN, NR RAN). Furthermore, the base station device 3 in the above-described embodiment may have some or all of the functions of an upper node for the eNodeB and / or the gNB.

[0126] Furthermore, some or all of the terminal device 1 and base station device 3 in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit, or as a chipset. Each functional block of the terminal device 1 and base station device 3 may be individually formed into a chip, or some or all of them may be integrated into a chip. Furthermore, the integrated circuit method is not limited to LSI, and may be realized using a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it is also possible to use an integrated circuit based on that technology.

[0127] Furthermore, in the above-described embodiment, a terminal device is described as an example of a communication device, but the present invention is not limited to this and can also be applied to terminal devices or communication devices such as stationary or non-movable electronic devices installed indoors or outdoors, for example, AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0128] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like are also included within the scope of the gist of the present invention. Furthermore, various modifications of one aspect of the present invention are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiments are substituted with elements that achieve the same effect are also included.

[0129] One aspect of the present invention can be used, for example, in a communication system, a communication device (e.g., a mobile phone device, a base station device, a wireless LAN device, or a sensor device), an integrated circuit (e.g., a communication chip), or a program.

[0130] 1 (1A, 1B, 1C) Terminal device 3 Base station device 9 Wireless communication system 10, 30 Physical layer processing unit 10a, 30a Wireless transmission unit 10b, 30b Wireless reception unit 11, 31 Antenna unit 12, 32 RF unit 13, 33 Baseband unit 14, 34 Upper layer processing unit 4000 Frame 4010 TWT 4011 Service period 4012 Period

Claims

Claim 1. A terminal device comprising: a processing unit that performs carrier sense; and a transmission unit that transmits a data frame within a TWT (Target Wake Time) service period after the carrier sense. The parameters of the carrier sense are based on an access category. The access category and the TWT service period are related to each other. Claim 2. A communication method for a terminal device, the method comprising: performing carrier sense; and transmitting a data frame within a TWT (Target Wake Time) service period after the carrier sense. The parameters of the carrier sense are based on an access category. The access category and the TWT service period are related to each other.