Communication device and communication method

Abstract

This communication device comprises: a communication unit that has a first communication scheme for transmitting different frames on a plurality of links having different frequency bands and a second communication scheme for transmitting frames which are the same; and a control unit that switches between the first communication scheme and the second communication scheme on the basis of the communication quality on each of the plurality of links.

Description

Communication device and communication method

[0001] The present disclosure relates to a communication device and a communication method.

[0002] IEEE 802.11be is being formulated as the next standard for wireless LANs. One of the technologies used in IEEE 802.11be is MLO. In existing Wi-Fi (registered trademark), one terminal device (also called a non-AP STA or simply an STA) communicates with a base station (also called an AP) using one frequency band. However, in MLO, one terminal device (also called a non-AP MLD) communicates with one base station (also called an AP MLD) using multiple frequency bands. A non-AP MLD is a device that integrates STAs of multiple frequency bands, and an AP MLD is a device that integrates APs of multiple frequency bands. Note that LAN stands for local area network. IEEE stands for Institute of Electrical and Electronics Engineers. MLO stands for multilink operation. STA stands for station. AP stands for access point. MLD stands for multi-link device. In the following description, a non-AP MLD may be simply referred to as an STA, and an AP MLD may be simply referred to as an AP. In the context of MLO, an STA may be interpreted as a non-AP MLD, and an AP may be interpreted as an AP MLD.

[0003] Patent Document 1 proposes an AP device that efficiently implements MLO in a wireless LAN system that applies MLO to various use cases.

[0004] JP 2023-99242 A

[0005] MLO communications utilize multiple frequency bands. Therefore, the communication quality of MLO may differ among the multiple frequency bands, and the transmission efficiency of a certain frequency band may decrease. In MLO, even if the transmission efficiency of a certain frequency band decreases, it is desirable to suppress the decrease in transmission efficiency across all frequency bands.

[0006] Non-limiting embodiments of the present disclosure contribute to providing a communication device and a communication method that suppress a decrease in transmission efficiency in MLO.

[0007] A communication device according to one embodiment of the present disclosure includes a communication unit having a first communication method for transmitting different frames over multiple links with different frequency bands and a second communication method for transmitting the same frames, and a control unit that switches between the first communication method and the second communication method based on the communication quality over each of the multiple links.

[0008] In a communication method according to one embodiment of the present disclosure, a communication device has a first communication method in which different frames are transmitted over multiple links having different frequency bands, and a second communication method in which the same frames are transmitted, and switches between the first communication method and the second communication method based on the communication quality over each of the multiple links.

[0009] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0010] According to an embodiment of the present disclosure, it is possible to suppress a decrease in transmission efficiency in MLO.

[0011] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features.

[0012] 1 is a diagram illustrating an example of the configuration of a wireless system according to an embodiment of the present disclosure; 2 is a diagram illustrating MLO; 3 is a diagram illustrating an aggregation method in MLO; 4 is a diagram illustrating a duplication method in MLO; 5 is a diagram illustrating the relationship between frequency bands and transmission distance / transmission capacity; 6 is a diagram illustrating the relationship between frequency bands and transmission distance / transmission capacity; 7 is a diagram illustrating degradation of communication quality; 8 is a diagram illustrating switching of communication methods based on radio wave strength; 9 is a diagram illustrating switching of communication methods when radio wave strength decreases according to transmission distance; 10 is a diagram illustrating switching of communication methods when radio wave strength decreases according to transmission distance; 11 is a diagram illustrating switching of communication methods based on transmission delay;

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0014] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0015] <System Configuration> Fig. 1 is a diagram showing an example configuration of a wireless system 1 according to an embodiment of the present disclosure. As shown in Fig. 1, the wireless system 1 includes a base station 11 and terminals 12a and 12b.

[0016] The base station 11 and the terminals 12a and 12b perform wireless communication based on a wireless LAN. For example, the base station 11 and the terminals 12a and 12b perform wireless communication based on MLO, which is one of the techniques used in IEEE802.11be.

[0017] The number of base stations 11 and terminals 12a, 12b is not limited to the example in Fig. 1. The base station 11 may be referred to as an AP or a communication device. The terminal 12 may be referred to as an STA or a communication device. Hereinafter, when there is no need to distinguish between the terminals 12a, 12b, they may be simply referred to as terminals 12.

[0018] <MLO> Fig. 2 is a diagram for explaining the MLO. In Fig. 2, the same components as in Fig. 1 are denoted by the same reference numerals.

[0019] 2, the base station 11 has an MLD 21. The terminal 12 has an MLD 22. MLD is an abbreviation for multilink device.

[0020] The MLD 21 has three physical layers (PHY1 to PHY3), three lower MAC layers (Lower MAC1 to Lower MAC1), and one upper MAC layer (Upper MAC). Similarly, the MLD 22 has three physical layers (PHY1 to PHY3), three lower MAC layers (Lower MAC1 to Lower MAC1), and one upper MAC layer (Upper MAC).

[0021] The MLD 21 and the MLD 22 establish a maximum of three links. For example, as shown in FIG. 2, PHY1 and Lower MAC1 of the MLD 21 and PHY1 and Lower MAC1 of the MLD 22 establish a 2.4 GHz link. PHY2 and Lower MAC2 of the MLD 21 and PHY2 and Lower MAC2 of the MLD 22 establish a 5 GHz link. PHY3 and Lower MAC3 of the MLD 21 and PHY3 and Lower MAC3 of the MLD 22 establish a 6 GHz link. In other words, the terminal 12 can communicate with the base station 11 using three different frequency bands simultaneously.

[0022] The number of frequency bands for MLO is not limited to three. The frequency bands used for MLO are not limited to 2.4 GHz, 5 GHz, and 6 GHz. A link may be referred to as a channel. The lower MAC layer and the upper MAC layer may be referred to as a MAC layer.

[0023] For simplicity, the following description will be given assuming that the number of MLO links is three. The frequency bands for the three links are 2.4 GHz, 5 GHz, and 6 GHz. Note that IEEE802.11be MLO uses the three frequency bands of 2.4 GHz, 5 GHz, and 6 GHz.

[0024] <Communication Method in MLO> As communication methods in MLO, aggregation method and duplication method are assumed.

[0025] <Communication method in MLO: Aggregation method> Fig. 3 is a diagram explaining the aggregation method in MLO. Fig. 3 shows the MLDs 21 and 22 explained in Fig. 2. In Fig. 3, for simplicity of explanation, the aggregation method will be explained assuming that the number of links in the MLO is two.

[0026] In the aggregation method, different frames are transmitted over multiple links with different frequency bands. For example, as shown in Figure 3, frames 1, 3, 5, 7, and 9 are transmitted from MLD 21 to MLD 22 over link 3, and frames 2, 4, 6, 8, and 10 are transmitted from MLD 21 to MLD 22 over link 2. The frames may also be referred to as packets, data, or signals.

[0027] In the aggregation method, different frames are transmitted over multiple links with different frequency bands, thereby increasing the speed of data communication.

[0028] <Communication method in MLO: Duplication method> Fig. 4 is a diagram explaining the duplication method in MLO. Fig. 3 shows the MLDs 21 and 22 explained in Fig. 2. In Fig. 4, for simplicity of explanation, the duplication method will be explained assuming that the number of links in the MLO is two.

[0029] In the duplication method, the same frame is transmitted over multiple links with different frequency bands. For example, as shown in Figure 4, frames 1, 2, 3, 4, and 5 are transmitted from MLD 21 to MLD 22 over link 3, and frames 1, 2, 3, 4, and 5 are transmitted from MLD 21 to MLD 22 over link 2.

[0030] In the duplication method, the same frame is transmitted over multiple links, thereby improving the reliability of data communication.

[0031] <Relationship Between Frequency Band and Transmission Distance / Transmission Capacity> Figures 5 and 6 are diagrams showing the relationship between frequency band and transmission distance / transmission capacity. As shown in Figures 5 and 6, the transmission distance (distance from the base station 11) and transmission capacity differ depending on the frequency band (strictly speaking, there are factors other than the frequency band as well).

[0032] For example, the transmission distance in the 2.4 GHz frequency band is farther (longer) than the transmission distance in the 5 GHz frequency band, and the transmission distance in the 6 GHz frequency band is closer (shorter) than the transmission distance in the 5 GHz frequency band.

[0033] For example, the transmission capacity in the 2.4 GHz frequency band is smaller than the transmission capacity in the 5 GHz frequency band, and the transmission capacity in the 6 GHz frequency band is larger than the transmission capacity in the 5 GHz frequency band.

[0034] <Study> Fig. 7 is a diagram for explaining the deterioration of communication quality, which shows the relationship between the frequency bands shown in Fig. 6 and the transmission distance / transmission capacity.

[0035] As the terminal 12 moves, the distance between the terminal 12 and the base station 11 becomes closer and farther, and therefore the communication quality between the base station 11 and the terminal 12 changes in the multiple frequency bands (multiple links).

[0036] For example, when the distance between base station 11 and terminal 12 is sufficiently short, the communication quality between base station 11 and terminal 12 is good, and base station 11 and terminal 12 can communicate using three frequency bands: 6 GHz, 5 GHz, and 2.4 GHz.

[0037] When the distance between the base station 11 and the terminal 12 is sufficiently close, and the terminal 12 moves away from the base station 11, the communication quality in the highest frequency band of 6 GHz deteriorates, for example, as shown in box A7a in Fig. 7. In the 6 GHz frequency band, for example, data retransmissions occur frequently, increasing delays. Therefore, the transmission efficiency in the 6 GHz frequency band decreases.

[0038] Furthermore, as the terminal 12 moves farther away from the base station 11, the communication quality deteriorates in the 5 GHz frequency band, which is the second highest frequency band after 6 GHz, as shown in box A7b in Fig. 7. In the 5 GHz frequency band, for example, data retransmissions occur frequently, increasing delays. Therefore, the transmission efficiency in the 5 GHz frequency band decreases.

[0039] Furthermore, the transmission efficiency in each frequency band can be reduced not only by the distance between the base station 11 and the terminal 12 but also by non-line-of-sight communication due to obstructions, reflections, noise, and the like.

[0040] Furthermore, when data delays occur, for example, IP packets are frequently reordered. In real-time transmission of video and audio, reordering of IP packets degrades QoE. IP stands for Internet Protocol. QoE stands for Quality of Experience.

[0041] Therefore, when the communication quality is good, the terminal 12 realizes large-capacity transmission with low delay, and when the communication quality deteriorates, suppresses a decrease in transmission efficiency.

[0042] <Switching of Communication Method> The terminal 12 switches between the aggregation method and the duplication method to suppress a decrease in transmission efficiency. Communication between the base station 11 and the terminal 12 includes downlink transmission from the base station 11 to the terminal 12 and uplink transmission from the terminal 12 to the base station 11. The communication method may be determined and switched independently for the downlink and the uplink. In some embodiments, a case where the communication method for the uplink transmitted by the terminal 12 is determined and switched on the terminal 12 side is mainly described, but other cases may also be applied. For example, the communication method for the downlink transmitted by the base station 11 may be determined and switched on the base station 11 side. Furthermore, the communication partner may be instructed to switch the communication method in the opposite direction. For example, the communication method for the downlink transmitted from the base station 11 may be determined on the terminal 12 side, and the terminal 12 may instruct the base station 11 on the downlink communication method.

[0043] <Switching of Communication Methods: Switching Based on Radio Wave Intensity> The terminal 12 may switch between the aggregation method and the duplication method based on radio wave intensity such as RSSI.

[0044] 8 is a diagram for explaining switching of communication methods based on radio wave intensity, and shows the MLDs 21 and 22 described in FIG.

[0045] The terminal 12 measures the received signal strength of radio waves in each frequency band (each link). When the measured received signal strength in a certain frequency band is lower than a predetermined threshold, the terminal 12 duplicates the link in the certain frequency band with a link in a frequency band lower than the certain frequency band.

[0046] For example, terminal 12 communicates wirelessly using the aggregation method, as indicated by arrow A8a in Fig. 8. When the received signal strength in the 6 GHz band falls below threshold α, terminal 12 duplicates the link in the 6 GHz band and the link in the 5 GHz band, which is the next lowest band after 6 GHz, as indicated by arrow A8b in Fig. 8 (switches to the duplication method). In this way, terminal 12 improves the reliability of data communication in the 6 GHz band and suppresses a decrease in transmission efficiency.

[0047] After switching to the duplication method, if the received signal strength in the 6 GHz band becomes greater than the threshold value β, the terminal 12 switches to the aggregation method, thereby enabling the terminal 12 to achieve faster data communication.

[0048] The threshold value α and the threshold value β may be the same value (α=β) or may be different values ​​(α≠β). When the threshold value α and the threshold value β are set to different values, frequent switching between the aggregation method and the duplication method is suppressed.

[0049] The same thresholds are set for the 5 GHz band as for the 6 GHz band. For example, when the received signal strength in the 5 GHz band falls below threshold α1, terminal 12 duplicates the link in the 5 GHz band and the link in the 2.4 GHz band. For example, when the received signal strength in the 5 GHz band exceeds threshold β1, terminal 12 aggregates the link in the 5 GHz band and the link in the 2.4 GHz band.

[0050] 9 and 10 are diagrams illustrating switching of communication methods when radio wave intensity (communication quality) decreases depending on the transmission distance. In Fig. 9, the same components as in Fig. 7 are assigned the same reference numerals. Fig. 10 shows the MLDs 21 and 22 described in Fig. 2.

[0051] Within the distance indicated by the double-headed arrow A9a in FIG. 9, the terminal 12 performs wireless communication using the aggregation method on a 6 GHz band link, a 5 GHz band link, and a 2.4 GHz band link, as indicated by the arrow A10a in FIG.

[0052] As explained in Fig. 7, for example, the communication quality in the high frequency band deteriorates faster than that in the low frequency band as the distance between the base station 11 and the terminal 12 increases. At the distance indicated by the double-headed arrow A9b in Fig. 9, the radio wave strength in the 6 GHz band decreases. At the distance indicated by the double-headed arrow A9b in Fig. 9, the terminal 12 duplicates the link in the 6 GHz band and the link in the 5 GHz band, as indicated by the arrow A10b in Fig. 10. This allows the terminal 12 to improve the reliability of data communication in the 6 GHz band and suppress a decrease in transmission efficiency.

[0053] At the distance indicated by the double-headed arrow A9c in Fig. 9, the terminal 12 aggregates the 5 GHz band link and the 2.4 GHz band link as indicated by the arrow A10c in Fig. 10. This enables the terminal 12 to achieve high-speed data communication.

[0054] At the distance indicated by the double-headed arrow A9d in Fig. 9, the radio wave strength of the 5 GHz band decreases. At the distance indicated by the double-headed arrow A9d in Fig. 9, the terminal 12 duplicates the link in the 5 GHz band and the link in the 2.4 GHz band, as indicated by the arrow A10d in Fig. 10. This allows the terminal 12 to improve the reliability of data communication in the 5 GHz band and suppress a decrease in transmission efficiency.

[0055] Within the distance indicated by the double-headed arrow A9e in FIG. 9, the terminal 12 performs wireless communication only in the 2.4 GHz band, as indicated by the arrow A10e in FIG.

[0056] In the above example, when the reception strength of a high frequency band decreases, a link in a high frequency band and a link in a low frequency band are duplicated. However, this is not limiting. When the reception strength of a low frequency band decreases, a link in a low frequency band and a link in a high frequency band may be duplicated. For example, when the radio wave strength of the 6 GHz band and the 2.4 GHz band does not decrease, but the radio wave strength of the 5 GHz band decreases, a link in a 5 GHz band and a link in a 6 GHz band may be duplicated.

[0057] <Switching of Communication Methods: Switching Due to Transmission Delay> The terminal 12 may switch between the aggregation method and the duplication method based on the transmission delay between links. For example, the terminal 12 may switch between the aggregation method and the duplication method when congestion causes a data transmission delay and frequent reordering of frames between links.

[0058] 11 is a diagram for explaining switching of communication methods based on transmission delay, and shows the MLDs 21 and 22 described in FIG.

[0059] For example, the terminal 12 performs wireless communication in the aggregation method, as indicated by an arrow A11a in FIG.

[0060] 11, for example, congestion such as waiting for data transmission by a certain terminal (a terminal other than terminal 12) causes a delay in transmitting frames to base station 11 in the 6 GHz band. If frame order rearrangements occur frequently due to the transmission delay, terminal 12 duplicates a link in the 6 GHz band and a link in the 5 GHz band, which is the next smallest band after 6 GHz, as shown by arrow A11c in FIG.

[0061] More specifically, when the number of frame reorderings per unit time exceeds threshold α due to transmission delays at 6 GHz, terminal 12 duplicates the link in the 6 GHz band with the link in the 5 GHz band, which is the next smallest band after 6 GHz, as indicated by arrow A11c in Fig. 11. This allows terminal 12 to improve the reliability of data communication in the 6 GHz band.

[0062] After switching to the duplication method, if the received signal strength in the 6 GHz band becomes greater than the threshold value β, the terminal 12 switches to the aggregation method, thereby enabling the terminal 12 to achieve faster data communication.

[0063] In the above description, after switching to the duplication method, if the received signal strength in the 6 GHz band becomes greater than the threshold value β, the terminal 12 switches to the aggregation method. However, this is not limited to this. The terminal 12 may also switch to the aggregation method if the number of frame reorderings per unit time due to transmission delays in the 6 GHz band becomes smaller than the threshold value γ. The threshold values ​​α and γ may be the same value (α = γ) or different values ​​(α ≠ γ). When the threshold values ​​α and γ are set to different values, frequent switching between the aggregation method and the duplication method is suppressed.

[0064] Furthermore, in the example of FIG. 11, the terminal 12 duplicates the link in the 6 GHz band and the link in the 5 GHz band, but it may also duplicate the link in the 6 GHz band and the link in the 2.4 GHz band.

[0065] Furthermore, if frame order changes occur frequently due to transmission delays at 5 GHz, for example, the terminal 12 may duplicate the link in the 5 GHz band with the link in the 2.4 GHz band or the link in the 6 GHz band.

[0066] Furthermore, if frame order changes occur frequently due to transmission delays in 2.4 GHz, for example, the terminal 12 may duplicate a link in the 2.4 GHz band with a link in the 5 GHz band or a link in the 6 GHz band.

[0067] <Switching of Communication Methods: Switching Based on Transmission Rate> The terminal 12 may switch between the aggregation method and the duplication method based on the transmission rate (data rate) between the links. For example, the terminal 12 may switch between the aggregation method and the duplication method based on the transmission rate determined by the MCS, bandwidth, GI, frame loss rate, and / or frame delay. MCS is an abbreviation for Modulation and Coding Scheme. GI is an abbreviation for Guard Interval.

[0068] 12 is a diagram for explaining switching of communication methods based on transmission rates, and shows the MLDs 21 and 22 described in FIG.

[0069] For example, the terminal 12 performs wireless communication in the aggregation method, as indicated by an arrow A12a in FIG.

[0070] As shown in box A12b in Fig. 12, for example, if the MCS (coding rate) for the 6 GHz band is smaller than the MCS for the 5 GHz band, and the transmission rate for the 6 GHz band is smaller than the transmission rate for the 5 GHz band, terminal 12 duplicates the link in the 6 GHz band and the link in the 5 GHz band, which is the next smallest band after 6 GHz, as shown by arrow A12c in Fig. 12. This enables terminal 12 to improve the reliability of data communication in the 6 GHz band.

[0071] After switching to the duplication method, if the MCS for the 6 GHz band becomes greater than the MCS for the 5 GHz band and the transmission rate for the 6 GHz band becomes greater than the transmission rate for the 5 GHz band, the terminal 12 switches to the aggregation method, thereby enabling the terminal 12 to achieve faster data communication.

[0072] When the transmission rate in the 5 GHz band becomes lower than the transmission rate in the 2.4 GHz band, the terminal 12 duplicates the link in the 5 GHz band and the link in the 2.4 GHz band. This allows the terminal 12 to improve the reliability of data communication in the 5 GHz band. After duplicating the link in the 5 GHz band and the link in the 2.4 GHz band, if the transmission rate in the 5 GHz band becomes higher than the transmission rate in the 2.4 GHz band, the terminal 12 switches to the aggregation method. This allows the terminal 12 to increase the speed of data communication.

[0073] <Switching of Communication Method: Switching in Cooperation with APL> The terminal 12 may switch between the aggregation method and the duplication method in cooperation with an application (APL). To enable the APL to instruct the terminal 12 to switch, the terminal 12 is provided with an interface that externally instructs the aggregation method or the duplication method. The interface for instructing the switching of communication methods uses an interface for the data plane or an interface for the control plane. Typically, the former is controlled via a Service Access Point (SAP) in the Media Access Control (MAC) layer, and the latter is controlled via a MAC Layer Management Entity (MLME).

[0074] When the movement and stopping of the terminal 12 are controlled For example, if the terminal 12 is a robot or the like and the movement and stopping of the terminal 12 is controlled by an APL, the terminal 12 switches the communication method from the aggregation method to the duplication method before the terminal 12 starts moving based on the APL. The terminal 12 may duplicate two of the three links, or may duplicate all three links. This allows the terminal 12 to improve communication reliability even if communication quality deteriorates due to, for example, the movement of the terminal 12.

[0075] After the terminal 12 has been stopped based on the APL, the terminal 12 switches the communication method from the duplication method to the aggregation method, thereby enabling the terminal 12 to achieve higher data communication speeds.

[0076] The movement and stopping of the terminal 12 based on the APL may be controlled by an external device separate from the terminal 12 .

[0077] When the movement and stopping of the terminal 12 are not controlled For example, when the terminal 12 is a smartphone, a wearable camera, or the like, and the movement and stopping of the terminal 12 are not controlled by an APL, the terminal 12 determines whether the terminal 12 is moving or stopping based on the GPS position information and the acceleration signal of the acceleration sensor, and switches the communication method from the aggregation method to the duplication method. GPS is an abbreviation for global positioning system.

[0078] For example, when the terminal 12 transitions from stationary to moving, the terminal 12 switches the communication method from the aggregation method to the duplication method. This allows the terminal 12 to improve the reliability of communication even if the communication quality deteriorates due to the movement of the terminal 12, for example.

[0079] For example, when the terminal 12 transitions from moving to stationary, the terminal 12 switches the communication method from the duplication method to the aggregation method, thereby enabling the terminal 12 to achieve a higher speed of data communication.

[0080] <Switching of Communication Methods: Switching at GOP Boundaries of Video Frames> The terminal 12 may switch the communication method at group of pictures (GOP) boundaries of video frames. In other words, the terminal 12 does not need to switch the communication method at any other boundary than the GOP boundaries of video frames. This allows the terminal 12 to provide, for example, stable video without any disturbances.

[0081] <Switching of Communication Methods: Switching Based on I-Pictures> The terminal 12 may transmit video I-pictures using a duplication method, which allows the terminal 12 to improve the reliability of video playback.

[0082] <APL Operation When Communication Method is Switched> When the communication method is switched due to the movement of the terminal 12, the APL may perform the following operation.

[0083] When the communication method is switched, the video transmission APL changes the encoding amount, frame rate, and video resolution.

[0084] For example, when the video transmission APL is switched from the aggregation method to the duplication method, the video resolution is reduced.

[0085] For example, when the video transmission APL is switched from the duplication method to the aggregation method, it transmits low-priority data such as high-layer data of SVC (Scalable Video Coding) and P / B pictures of a GOP.

[0086] When the terminal 12 switches the communication method, the terminal 12 may notify the APL that the communication method has been switched. The notification is performed, for example, via MLME of the control plane. This allows the APL to know the state of the terminal 12 not only when the APL instructs the terminal 12 to switch the communication method, but also when the terminal 12 autonomously determines to switch the communication method, thereby enabling appropriate control thereafter. The APL may be implemented in the terminal 12, or in another device (a device with which the terminal 12 is communicating) located upstream of the base station 11. The APL may control the communication volume of video data in response to the notification from the terminal 12.

[0087] <Multi-stage switching of communication method> The terminal 12 may switch the communication method in multiple stages using FEC instead of two stages, namely, the aggregation method and the duplication method. FEC stands for Forward Error Correction. FEC may be performed on a frame-by-frame basis.

[0088] 13 is a diagram for explaining multi-stage switching of communication methods, showing the MLDs 21 and 22 described in FIG.

[0089] 13, an arrow A13a indicates a communication method in the aggregation method, an arrow A13b indicates a communication method with a coding rate of 3 / 4, an arrow A13c indicates a communication method with a coding rate of 2 / 3, and an arrow A13d indicates a communication method in the duplication method.

[0090] The terminal 12 switches between a communication method using the aggregation scheme, a communication method using a coding rate of 3 / 4, a communication method using a coding rate of 2 / 3, and a communication method using the duplication scheme, for example, based on the MCS and / or loss rate (retransmission rate) in each frequency band. The terminal 12 may calculate an optimal coding rate based on the MCS and / or loss rate (retransmission rate) in each frequency band, and switch the communication method in multiple stages.

[0091] The reliability of communication improves in the following order: aggregation communication system, 3 / 4 coding rate communication system, 2 / 3 coding rate communication system, duplication communication system. The communication speed improves in the following order: duplication communication system, 2 / 3 coding rate communication system, 3 / 4 coding rate communication system, aggregation communication system.

[0092] In the above example, two communication methods with different coding rates are added to the aggregation method and the duplication method, and switching is performed in four stages, but this is not limiting. Three or more communication methods with different coding rates may be added.

[0093] In the above, the multi-stage communication method is switched based on the MCS and / or loss rate (retransmission rate), but the multi-stage communication method may also be switched based on at least one of the transmission delay, the transmission rate, and the movement speed of the terminal 12.

[0094] <Processing Layer> Fig. 14 is a diagram for explaining processing layer 1. Fig. 14 shows the MLDs 21 and 22 described in Fig. 2 and an upper layer 23. The upper layer 23 may be a layer higher than the MAC layer of the MLD 22, such as a network layer (such as IP), a transport layer (such as TCP), a presentation layer (such as a video codec), and an APL layer.

[0095] When the MLD 22 (MAC layer) switches the communication method, it notifies the upper layer 23 of information such as the switched communication method, the switched link, the switching cause, and / or the connection and disconnection of each frequency band (each link).

[0096] When the communication method is switched, for example, the transmission capacity between the base station 11 and the terminal 12 changes. Based on the information notified from the MLD 22, the upper layer 23 such as the APL layer changes, for example, the amount of data communicated by the terminal 12.

[0097] In the above description, the MLD 22 notifies the upper layer 23 of information such as the switched communication method, the switched link, the switching cause, and / or the connection and disconnection of each frequency band, but this is not limited to this. A middleware or a control unit other than the MLD 22 may notify the upper layer 23 of the above information.

[0098] Fig. 15 is a diagram for explaining the processing layer 2. In Fig. 15, the same components as in Fig. 14 are denoted by the same reference numerals.

[0099] The upper layer 23 stores information for switching (forcibly switching) the communication method in a predetermined field of the IP packet (for example, the TOS field, the DSCP field, the Diffserv field, or the ECN field). The MLD 22 (Upper MAC) references the predetermined field of the IP packet and switches the communication method. The information for switching the communication method may explicitly instruct the communication method, or may implicitly instruct using QoS information such as priority or other classification information. Since the IP packet is transmitted as the payload of a MAC layer frame, the switching instruction is made via the MAC SAP of the data plane.

[0100] For example, the upper layer 23 stores information for switching the communication method in the TOS field of an IP packet. When the TOS field indicates a priority, the MAC layer can interpret a specific priority value as an instruction for the communication method, thereby implicitly instructing the communication method. For example, the MAC layer interprets the header of the IP packet, which is the payload of the MAC frame, and sets the access category (AC) and traffic identifier (TID) in the MAC layer to corresponding values ​​depending on the value of the TOS field included therein. If the value of the TOS field indicates a high priority (i.e., if the set AC and TID indicate a high priority), the communication method may be determined to be high in importance and switched to the duplication method. If the value of the TOS field indicates a low priority (i.e., if the set AC and TID indicate a low priority), the communication method may be determined to be low in importance and switched to the aggregation method. More specifically, if the set AC is AC_VO (Voice), the communication method may be set to the duplication method as a high priority, and if the set AC is AC_BE (Best Effort), the communication method may be set to the aggregation method as a low priority. For example, the MLD 22 refers to the TOS field of the IP packet and switches from the aggregation method to the duplication method, as shown in the dotted line box A15a in Fig. 15. For example, the MLD 22 refers to the TOS field of the IP packet and switches from the aggregation method to the duplication method, as shown in the dotted line box A15b in Fig. 15. TOS is an abbreviation for type of service.

[0101] Specifically, the control of switching between communication methods may be performed as follows, for example, using MLO's Traffic Identifier (TID)-To-Link Mapping (TTLM). A first TID is assigned to data of high importance, and the first TID is mapped to multiple links, with the same data frame (Mac Protocol Data Unit (MPDU)) being transmitted over all of the multiple links. As a result, data assigned the first TID is transmitted using the duplication method. A second TID is assigned to data of low importance, and the second TID is mapped to only one link. A third TID is assigned to data of medium importance, and the third TID is mapped to multiple links, with the same data (MPDU) being transmitted over only one link except in the case of retransmission. As a result, data assigned the third TID is transmitted using the aggregation method. When retransmitting, the data may be retransmitted over a link other than the initial transmission link among the multiple mapped links. In this way, when transmitting multiple types of data streams, the communication method can be set individually to the duplication method or the aggregation method for each type indicated by the TID. Note that the setting of the communication method for each data stream is not limited to a method based on the TID, but may also be based on other attributes related to the data stream, such as the AC, Traffic Stream ID (TSID), or SCS identifier (SCSID) used in the Stream Classification Service (SCS).

[0102] Note that forcibly switching may be considered to be switching by an upper layer 23 such as an APL layer. For example, forcibly switching may be considered to be switching without being based on radio wave strength, transmission delay (reordering of frames), and / or transmission rate.

[0103] The upper layer 23 sets the conditions for switching the communication method in the MLD 22. For example, the upper layer 23 sets thresholds for radio wave intensity, transmission delay (reordering of frames), and / or transmission rate.

[0104] In the above description, the upper layer 23 is assumed to forcibly switch the communication method and / or set the switching conditions, particularly using IP as an example. However, this is not limited to this. For example, the upper layer 23 may implicitly switch the communication method using a field indicating the type of coded video data in the presentation layer, and the MAC layer may switch based on this. Alternatively, a middleware or control unit separate from the upper layer 23 may forcibly switch the communication method and / or set the switching conditions. For example, a control unit within a terminal called an SME (station management entity) may determine the communication method based on the operation of an application or external conditions and instruct the MAC layer on the communication method via the MLME. As a specific example, the following procedure may be applied: A primitive requesting the addition or modification of an SCS stream corresponding to a specific SCSID includes an instruction on the communication method and the TID corresponding to the SCS stream. The SME issues the primitive to the MLME. When setting the communication method for transmission data, if multiple links are mapped to the corresponding TID, the MAC layer transmits the SCS stream data using the specified communication method using the multiple links. Furthermore, when instructing the communication method for received data, the MAC layer includes the communication method instructed via MLME in an SCS request frame and transmits it to the communication partner, instructing the communication partner to switch the communication method.

[0105] Fig. 16 is a diagram for explaining the processing layer 3. In Fig. 16, the same components as in Fig. 14 are denoted by the same reference numerals.

[0106] The communication method may be switched by the upper layer 23. In this case, the upper MAC layer of the MLD 22 may be omitted as shown in FIG.

[0107] The MLD 22 notifies the upper layer 23 of information such as radio wave intensity, transmission delay (frame reordering), transmission rate, and / or connection and disconnection of each link. The upper layer 23 switches the communication method based on the information. The upper layer 23 switches the communication method, for example, on an IP packet basis.

[0108] In the above description, the upper layer 23 switches the communication method, but this is not limiting. Middleware or a control unit other than the MLD 21 and the upper layer 23 may switch the communication method.

[0109] 17 is a diagram showing an example of the hardware configuration of the terminal 12. As shown in FIG. 17, the terminal 12 has a control unit 31, a communication unit 32, and a storage unit 33.

[0110] The control unit 31 controls the entire terminal 12. The control unit 31 may be configured by a processor such as a central processing unit (CPU). The functions of the MLD 22 may be realized by the control unit 31.

[0111] The communication unit 32 communicates with the base station 11. For example, the communication unit 32 communicates with the base station 11 using the aggregation method and the duplication method. The communication unit 32 also communicates with a device that is a communication partner of the terminal 12.

[0112] The storage unit 33 stores an operating system (OS) program, middleware programs, and application programs to be executed by the control unit 31. The storage unit 33 also stores various data necessary for processing by the control unit 31. The storage unit 33 may be, for example, a solid state drive (SSD), a random access memory (RAM), a flash memory, a read only memory (ROM), and / or a hard disk drive (HDD).

[0113] As described above, the terminal 12 switches between the aggregation method and the duplication method for multiple links in different frequency bands. This operation allows the terminal 12 to suppress a decrease in transmission efficiency in MLO.

[0114] <Modifications> In the above, the terminal 12 switches the communication method, but this is not limiting. The base station 11 may switch the communication method. Alternatively, both the base station 11 and the terminal 12 may switch the communication method.

[0115] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear to those skilled in the art that various modifications or alterations can be made within the scope of the claims. It is understood that such modifications or alterations also fall within the technical scope of the present disclosure. Furthermore, the components of the embodiments may be arbitrarily combined without departing from the spirit of the present disclosure. For example, the base station 11 may switch communication methods by combining two or more of radio wave strength, transmission delay, transmission rate, APL linkage, video frame, and I-picture.

[0116] In the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuit," "... assembly," "... device," "... unit," or "... module."

[0117] The present disclosure can be realized by software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may also be called an IC, system LSI, super LSI, or ultra LSI.

[0118] The integrated circuit method is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0119] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology may be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

[0120] The present disclosure can be implemented in any type of apparatus, device, or system (collectively referred to as a communication apparatus) having a communication function. The communication apparatus may include a radio transceiver and processing / control circuitry. The radio transceiver may include a receiver and a transmitter, or both as functions. The radio transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0121] The communication devices are not limited to portable or mobile devices, but also include any kind of non-portable or fixed equipment, devices, and systems, such as smart home devices (such as home appliances, lighting equipment, smart meters or measuring devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0122] Communications include data communications via cellular systems, wireless LAN systems, communication satellite systems, and the like, as well as data communications via combinations of these.

[0123] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0124] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0125] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2023-212404, filed on December 15, 2023, are incorporated herein by reference in their entirety.

[0126] The present disclosure is useful for wireless LANs that use MLO.

[0127] REFERENCE SIGNS LIST 1 Wireless system 11 Base station 12, 12a, 12b Terminal 21, 22 MLD 23 Upper layer 31 Control unit 32 Communication unit 33 Storage unit

Claims

1. A communication device having a communication unit having a first communication method for transmitting different frames over multiple links having different frequency bands and a second communication method for transmitting the same frame, and a control unit that switches between the first communication method and the second communication method based on the communication quality over each of the multiple links.

2. The communication device according to claim 1, wherein the control unit switches between the first communication method and the second communication method based on radio wave strength in each of a plurality of links, frame order change, or transmission rate.

3. The communication device according to claim 1, wherein the control unit further switches between the first communication method and the second communication method based on movement and stoppage of the communication device.

4. The communication device according to claim 1, wherein the control unit further switches between the first communication method and the second communication method at a boundary between group of pictures (GOP) of a video frame.

5. The communication device according to claim 1, wherein the control unit switches to the second communication method when an I-picture of a video frame is transmitted.

6. The communication device according to claim 1, wherein the control unit switches between the first communication method, the second communication method, and a third communication method in which a coding rate is changed and frames are transmitted.

7. The communication device according to claim 1, wherein switching between the first communication method and the second communication method is a function of a Medium Access Control (MAC) layer.

8. The communication device according to claim 1, wherein switching between the first communication method and the second communication method is a function of a layer higher than a MAC layer.

9. A communication method, in which a communication device has a first communication method in which different frames are transmitted over a plurality of links having different frequency bands, and a second communication method in which the same frame is transmitted, and switches between the first communication method and the second communication method based on communication quality over each of the plurality of links.

Images