Wireless communication method, terminal and access point

Abstract

The invention discloses a wireless communication method, a terminal and an access point, relates to the field of wireless communication, and is used for accurately and efficiently solving the communication conflict problem of a multi-terminal access system. In the multi-terminal access system, after the terminal accesses the system, the first information is utilized to clearly indicate that the uplink time slot is occupied in the downlink channel, so that the terminal which does not access the system pauses to access the system in the uplink time slot when detecting the first information. According to the method, unnecessary access loss can be avoided, the access number of large-scale terminals is increased, the conflict number is reduced, the channel utilization rate is increased, and time slot waste of unified control is avoided.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication, and in particular to a wireless communication method, a terminal, and an access point. Background Art

[0002] The Internet of Things connects people and things, and things and things through communication technologies, thereby enhancing convenience. In local area network communication scenarios such as smart homes and industrial data collection, short-range communication technologies are generally used. However, for wide-range and long-distance scenarios, long-distance communication technologies are required. LPWAN (Low Power Wide Area Network) technology is a long-distance wireless communication technology that emerged to meet the needs of the Internet of Things.

[0003] The core of a wide-area wireless Internet of Things is large coverage, low power consumption, a large number of connections, and low cost. Among them, a huge number of connections is one of the most typical characteristics. Systems with a large number of access terminals need to solve the conflict problem of multi-terminal access.

[0004] In existing wide-area wireless Internet of Things communication technologies, for the access of terminals (including initial access and data transmission after access), such as communication protocols like LoRa and SigFox, some directly send data without detecting conflicts and resend the data if no response is received. This access technology has a relatively large and uncontrollable conflict probability. Some communication protocols detect the existence of conflicts based on channel quality, such as the NB-IoT communication protocol, and then randomly avoid for a period of time and re-detect the channel state. Since the channel state needs to be evaluated, there are problems of detection errors and the detection operation is relatively complex. Summary of the Invention

[0005] The object of the present invention is to provide a wireless communication method, a terminal, and an access point to accurately and efficiently solve the communication conflict problem of a multi-terminal access system for all or part of the above problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A wireless communication method is applied to a multi-terminal access system; it includes:

[0008] In the multi-terminal access system, the first information is used in the downlink channel to clearly indicate that the uplink time slot is occupied, so that a terminal that has not accessed the system pauses accessing the system in the uplink time slot when detecting the first information.

[0009] Further, the using the first information in the downlink channel to clearly indicate the occupancy status of the uplink time slot includes:

[0010] The first information is sent in the downlink time slot corresponding to the terminal allowed to access the system in the downlink channel to clearly indicate that the uplink time slot of the terminal allowed to access the system is occupied.

[0011] Further, the first information clearly indicates the uplink time slots occupied by the terminals allowed to access the system.

[0012] Further, sending the first information in the downlink time slots corresponding to the terminals allowed to access the system includes:

[0013] Sending the first information in all the downlink time slots corresponding to the uplink time slots occupied by the terminals allowed to access the system.

[0014] Further, making the terminals not yet accessing the system pause accessing the system in this uplink time slot when detecting the first information includes:

[0015] Making the terminals not yet accessing the system pause accessing the system in the uplink time slot when detecting the first information in the downlink time slot.

[0016] Further, the first information is a clear identifier or the information carried in a clear identifier.

[0017] Further, the first information is invalid for the terminals allowed to access the system.

[0018] Further, the method further includes: using second information in the downlink channel to clearly indicate to the terminals allowed to access the system to ignore the first information.

[0019] The present invention also provides a terminal applied to a multi-terminal access system, and the terminal is configured to:

[0020] Before accessing the system, detect whether the downlink channel contains first information that clearly indicates that the uplink time slot is occupied; if the first information is detected, pause accessing the system in the uplink time slot.

[0021] The present invention also provides an access point applied to a multi-terminal access system, and the access point is configured to:

[0022] Use first information in the downlink channel to clearly indicate that the uplink time slot is occupied, so that the terminals not yet accessing the system pause accessing the system in the uplink time slot when detecting the first information.

[0023] In summary, due to adopting the above technical solutions, the beneficial effects of the present invention are:

[0024] This application uses the downlink channel to transmit the busy / idle status of the uplink time slot, enabling other terminals in that uplink time slot to actively avoid. Compared with the method of the terminal frequently performing idle channel assessment, on the one hand, since the first information in the downlink channel clearly indicates the busy / idle status of the uplink time slot, the certainty and accuracy are extremely high, and there will be no problem of detection errors. In the case of effectively solving access conflicts, it can effectively improve the large-scale access performance and uplink performance. On the other hand, the terminal only needs to perform intermittent information detection in each frame and does not need to frequently evaluate the channel status, which can effectively reduce the overall energy consumption of the system. Description of the Drawings

[0025] The present invention will be described by way of examples and with reference to the accompanying drawings, where:

[0026] Figure 1 is the signal interaction diagram of the multi-terminal access system in the embodiment of this application.

[0027] Figure 2 is the structural diagram of a data frame in the embodiment of this application.

[0028] Figure 3 is the structural diagram of another data frame in the embodiment of this application.

[0029] Figure 4 is the flowchart of the execution of the terminal configuration information in the embodiment of this application.

[0030] Figure 5 is the flowchart of the execution of the access point configuration information in the embodiment of this application. Detailed Embodiments

[0031] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0032] Any feature disclosed in this specification (including any additional claims, abstract) can be replaced by other equivalent or similar-purpose alternative features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only an example of a series of equivalent or similar features.

[0033] In response to the access conflict phenomenon that is prevalent in multi-terminal access systems, the existing technologies either ignore the conflict phenomenon and choose to continuously try to resend data to achieve successful data transmission, such as communication protocols such as LoRa and SigFox; or frequently evaluate the channel status by adopting methods such as CCA (Clear Channel Assessment) and access the system when the channel is assessed to be idle. However, this method is seriously affected by the channel environment, etc., and may cause inaccurate channel status evaluation, resulting in detection errors, and access conflicts may still occur, or there is no terminal access when the channel is idle, resulting in poor access performance. In response to these shortcomings, the embodiments of the present application provide a wireless communication method, terminal, and access point, which are intended to accurately and efficiently solve the access conflict problem of a multi-terminal access system, thereby avoiding unnecessary access conflicts and improving large-scale access performance and uplink performance.

[0034] In some embodiments, the wireless communication method provided by the present application includes:

[0035] In a multi-terminal access system, first information is used in a downlink channel to clearly indicate that an uplink time slot is occupied, so that a terminal that has not accessed the system will suspend accessing the system in the uplink time slot when detecting the first information.

[0036] When a large number of terminals access the system at the same time, access conflicts will occur. Figure 1 As shown, when a large-scale terminal is ready to access the system, it will send access requests in a certain uplink time slot of the uplink channel. When the system (through AP (Access Point) nodes such as base stations) receives each access request in the uplink time slot, it will only allow a certain terminal to access. In this regard, in a multi-terminal access system, after a terminal accesses the system in its uplink time slot, the system uses the first information in the downlink channel (of the frame occupied by the terminal allowed to access) to clearly inform other terminals that a certain uplink time slot is occupied. For a certain terminal, before accessing the system, it will first detect whether the downlink channel of the current frame contains the first information. If the first information is detected, it is considered that it cannot access the system in the current frame, and the access is suspended. Wait for the next frame and then re-detect whether the downlink channel contains the first information. This cycle is repeated until the first information is not detected in the downlink channel of a certain frame, and then the corresponding uplink time slot of the frame can be tried to access the system. This can avoid unnecessary channel evaluation and access attempts by the terminal, and reduce the overall energy consumption of the system. Moreover, through this method, the terminal does not need to make access attempts based on the channel evaluation results, but can directly decide whether to suspend access or directly access based on clear instructions. It will not cause access conflicts or unnecessary idleness of the channel due to detection errors, thereby improving access performance and uplink performance.

[0037] As an alternative implementation, embodiments of the present application regard each uplink time slot as a sub-channel that only allows a single terminal to access, which can be independently controlled to reduce the waste of time slots in unified control. There may be multiple terminals that want to access the system in each uplink time slot. Therefore, for each occupied uplink time slot, the system needs to clearly inform in the corresponding downlink time slot that the uplink time slot has been occupied. Therefore, the first information is used in the downlink channel to clearly indicate the occupancy status of the uplink time slot, including:

[0038] Send the first information in the downlink time slot corresponding to the downlink time slot of the terminal allowed to access the system to clearly indicate that the uplink time slot of the terminal allowed to access the system is occupied. In this way, when an unconnected terminal plans to access the system from a certain uplink time slot, it only needs to detect whether the first information is included in the corresponding downlink time slot to know the idle status of the uplink time slot, without having to frequently detect the first information in the frame structure of the entire downlink channel, which can further reduce the detection frequency of the terminal. When an unconnected terminal detects the first information in the downlink time slot (corresponding to the uplink time slot planned to access the system), it pauses accessing the system in the uplink time slot planned to access the system.

[0039] As an alternative implementation, the first information carried in the downlink channel clearly indicates the uplink time slot occupied by the terminal allowed to access the system. That is, it clearly indicates which uplink time slot the terminal allowed to access the system occupies, so that the idle time slots of the channel can be accurately distinguished, avoiding unnecessary waste of channel resources.

[0040] For example, for some frame structures, the downlink time slot and the uplink time slot are configured in a 1:1 relationship, such as Figure 2 the shown frame structure, where S represents the synchronization time slot, D represents the downlink time slot, U represents the uplink time slot, and G represents the gap time slot. It includes 8 downlink time slots and 8 uplink time slots. In this way, one downlink time slot corresponds to one uplink time slot. For such frame structures, only a clear identifier needs to be used in the downlink time slot to act as the first information to clearly indicate that the corresponding uplink time slot is in an occupied state. Correspondingly, the terminal only needs to detect whether the clear identifier is included in the downlink time slot to determine whether the uplink time slot planned to access is occupied.

[0041] As a feasible implementation, by sending a BNACK (Time Slot Busy Broadcast Packet, with a length of 1 / 8 of a short message) message in the downlink time slot to indicate that the corresponding uplink time slot has been occupied, in this uplink time slot, only the uplink data of the terminal allowed to access is allowed to access. And other terminals, after receiving the BNACK message in this downlink time slot, will indicate that the corresponding uplink time slot is in a busy state and pause the access plan in this uplink time slot; if the terminal does not receive the BNACK message in this downlink time slot, it indicates that the corresponding uplink time slot is idle, and it can then access the system in this uplink time slot.

[0042] For another frame structure, the configuration ratio of the downlink time slot to the uplink time slot is 1:2, that is, one downlink time slot corresponds to two uplink time slots at the same time. These two uplink time slots belong to different groups (assumed to be group0 and group1). As shown in Figure 3 the frame structure, 8 downlink time slots and 16 uplink time slots are configured. For such a frame structure, it is impossible to clearly indicate the occupancy status of the uplink time slot only by whether the BNACK message is included. It is necessary to further configure corresponding messages in the BNACK message to clearly indicate the uplink time slot occupied by the terminal allowed to access the system. Correspondingly, the terminals planning to access the system in the two uplink time slots (corresponding to the same downlink time slot) will receive the same BNACK message. The two terminals need to detect the BNACK message in the corresponding downlink time slot and further detect the specific information carried in the BNACK message to determine whether the uplink time slot planned to be accessed is occupied.

[0043] As a feasible implementation manner, 2-bit information is configured in the BNACK message to indicate the busy / idle status of the two uplink time slots corresponding to the downlink time slot. Assume that the 2-bit information is 0b10, which means that the uplink time slot of group0 is idle and the uplink time slot of group1 is occupied (if 0 is used to indicate occupied, it is vice versa). The terminals of the two uplink time slots will receive this BNACK message. Among them, the terminal using the uplink time slot of group0 can access the system, while the terminal using the uplink time slot of group1 suspends access. If both of the two uplink time slots are idle, the downlink time slot may not send a BNACK message, or it may send a BNACK message and the information carried in it is 0b00.

[0044] For other frame structure configurations, for example, a frame structure with a ratio of the number of downlink time slots to the number of uplink time slots of 1:K (K is a positive integer greater than 2), the principle is the same. For example, K-bit information is configured in the BNACK message to clearly indicate the specifically occupied uplink time slot.

[0045] In summary, the first information sent on the downlink channel can be a clear identifier, such as the BNACK message, or the information carried in a clear identifier, such as the 2-bit information carried in the BNACK message.

[0046] For a terminal allowed to access the system, its uplink data may need multiple data frames to be sent completely, that is, it occupies the corresponding uplink time slot in multiple consecutive data frames. In this regard, in some optional implementation manners, the first information is sent in all downlink time slots corresponding to the uplink time slots occupied by the terminal allowed to access the system.

[0047] In some embodiments, the system receives an access request from a terminal (a terminal allowed to access the system) in an uplink time slot of a certain frame, and then, based on the access request, marks the uplink time slots of the subsequent N frames (N is an integer determined by the amount of data identified in the access request) as occupied states, that is, all are occupied by the terminal, records the terminal information, and starts broadcasting the first information (such as the BNACK message in the previous embodiments) in the corresponding downlink time slot of the next frame. Before arranging the downlink time slot tasks, the system checks whether the uplink time slot of the current frame is in an occupied state according to the marked status. If so, it arranges to broadcast the first information in the downlink time slot corresponding to the uplink time slot. When other terminals planning to access the system in this uplink time slot detect the first information, they mark the current frame as a busy state, pause accessing the system in the current frame, and continue to wait for the detection result of the first information in the corresponding downlink time slot of the next frame, and so on in a loop until the first information is not detected in the corresponding downlink time slot, and then access the system in the corresponding uplink time slot later.

[0048] In addition, if due to communication anomalies, after a terminal that has already accessed the system sends uplink data in the uplink time slot of the next frame where the anomaly occurs, the system will re-mark the uplink time slots of the subsequent N frames as occupied states. That is, when the system fails to receive the subsequent uplink data from the terminal due to communication anomalies in a certain frame, it will still send the first information in the corresponding downlink time slots of the next N - 1 frames to reserve channel resources for the terminal to retransmit data.

[0049] In addition, the first information broadcast by the system in the downlink time slot can still be detected by the terminals allowed to access the system. Therefore, in some alternative embodiments, the first message sent in the downlink time slot is invalid for the terminals allowed to access the system. In this way, the terminals allowed to access the system continue to send uplink data, while other terminals that have not accessed in this uplink time slot pause accessing.

[0050] In some embodiments, in addition to sending the first information in the downlink channel to prevent other terminals from accessing, the system also sends the second information to clearly indicate the terminals allowed to access the system to ignore the first information. Only the terminals allowed to access the system can receive and decode the second information.

[0051] For example, when multiple terminals send access requests in a certain uplink time slot, the system only allows one terminal to access the system, and broadcasts the first information in the corresponding downlink time slot of the next frame to clearly indicate that the uplink time slot is occupied. In addition, ACK (feedback data packet, with a length of 1 / 8 of a short message) check information is also sent to the terminal allowed to access the system in this downlink time slot, indicating that the terminal is allowed to access the system. After receiving the ACK check information, the terminal enters the process of sending uplink data and can ignore the first information received in the same downlink time slot in subsequent frames until the current uplink data transmission ends.

[0052] In some embodiments, the terminal provided by the present application is configured to:

[0053] Before accessing the system, detect whether the downlink channel contains the first information that clearly indicates that the uplink time slot is occupied; if the first information is detected, suspend accessing the system in this uplink time slot. For the configuration information of the terminal, reference can be made to the relevant features of the wireless communication method described above, and details will not be elaborated here.

[0054] As an alternative implementation, before accessing the system, the terminal detects whether a certain downlink time slot of the downlink channel contains the first information, and this downlink time slot corresponds to the uplink time slot in which the terminal plans to access the system.

[0055] Such as Figure 4 Shown is a specific configuration method of the terminal provided by the embodiment of the present application. When the terminal is in the idle state, if there is data to be sent, it detects the first information (such as the BNACK message) in the downlink time slot corresponding to a certain uplink time slot in which it plans to access the system. If the first information is detected, it suspends accessing in the current frame and re-detects the first message in the corresponding downlink time slot of the next frame until the first information is not detected in the corresponding downlink time slot, and then accesses the system in the corresponding uplink time slot of the next frame to send uplink data, and then receives the ACK check information (serving as the second information) in the corresponding downlink time slot of the subsequent frame. If the ACK check information is not received, it indicates that the communication is abnormal. The terminal randomly backs off M frames (M is an integer) and then re-detects the first information in the corresponding downlink time slot and re-accesses the system in the (M + 1)-th frame; if the ACK check information is received, it determines whether the uplink data has been sent. If it has been sent, it returns to the idle state. If it has not been sent, it continues to send uplink data in the corresponding uplink time slot of the subsequent frame, and so on in a loop until the uplink data is sent and then returns to the idle state.

[0056] In some embodiments, the access point provided by the present application is configured to:

[0057] In the downlink channel, the first information is used to explicitly indicate that the uplink time slot is occupied, so that a terminal that has not accessed the system pauses accessing the system in the uplink time slot when detecting the first information. This configuration information is triggered after a certain terminal accesses the system in the uplink time slot.

[0058] For the access point, its configuration information can refer to the relevant features in the foregoing wireless communication method, so no detailed description will be given here.

[0059] As Figure 5 shown is a specific configuration method of the terminal provided by an embodiment of the present application. When the access point is in the idle state, if access requests (or called uplink data, including access packets or uplink data packets) of multiple terminals are received in an uplink time slot of a certain frame (assumed to be the Xth frame), only one of the terminals is allowed to access the system, that is, only one of the terminals is sent an ACK check message as a response in the corresponding downlink time slot of the next frame (the (X + 1)th frame). For the received uplink data, it is judged whether it is the last data packet, that is, it is detected how many frames of uplink time slots the terminal needs to occupy through the access request. If it is the last data packet, only the corresponding uplink time slot of the next frame (that is, the (X + 1)th frame) is marked as occupied; if it is not the last data packet, the corresponding uplink time slots of the subsequent N frames need to be marked as occupied, that is, the corresponding uplink time slots from the (X + 1)th frame to the (X + N)th frame are marked as occupied. Then, in the next frame, it is judged whether the current frame is the frame marked as the occupied uplink time slot. If so, the first information is sent in the corresponding downlink time slot of the current frame, and it is judged whether uplink data is received in the corresponding uplink time slot of the current frame. Otherwise, it is directly judged whether uplink data is received in the corresponding uplink time slot of the current frame; if uplink data is received in the current frame, an ACK check message is sent to the corresponding terminal, and the process returns to judging whether it is the last data packet. Otherwise, the process returns to judging whether the next frame is the frame marked as the occupied uplink time slot.

[0060] As a more illustrative embodiment, the configuration information of the access point can execute the following process:

[0061] Step 1: The access point receives an access request from terminal A in an uplink time slot of the first frame, marks the uplink time slot of the next N frames as busy (i.e., occupied), and records the information of the accessing terminal, and sends an ACK check message for terminal A in the corresponding downlink time slot of the second frame.

[0062] Step 2: Before arranging the downlink time slot task, the access point checks whether the state of the uplink time slot corresponding to the downlink time slot of the current frame is busy. If it is busy, a general BNACK message is sent.

[0063] Step 3: The terminal A receives the BNACK message in the downlink time slot of the second frame, marks the status of this frame as busy. At the same time, the terminal A receives the ACK check information and marks the entry into the uplink transmission process. Then it can ignore the busy status and continue to send uplink data until the end of this data transmission.

[0064] Step 4: Other terminal B receives the BNACK message in the downlink time slot of the second frame, or finds that the uplink time slot is busy after decoding the BNACK message. Then it marks the status of this frame as busy and believes that this frame cannot send uplink data or access, and continues to wait for the detection result of the downlink time slot in the next frame.

[0065] Step 5: Other terminal C, due to abnormal reception, does not receive the BNACK message in the downlink time slot of the second frame, and there is data to be sent at the same time. Then it will send an access request.

[0066] Step 6: If the access point continues to receive the uplink data packet of the terminal A in the third frame, it continues to mark the uplink time slots of the next N frames as busy. That is to say, if there is an abnormality in a certain frame and the subsequent uplink data packets of the terminal A are not received, it is still necessary to send the BNACK message in the corresponding downlink time slots of the subsequent (N - 1) frames to leave a retransmission channel for the terminal A.

[0067] Step 7: The access point receives the access request of the terminal C in the third frame. Since the current uplink process is for the terminal A, it does not respond to the access request of the terminal C.

[0068] Step 8: When the access point receives the last data packet uplinked by the terminal A, it clears the marks of the previous N frames and only marks the uplink time slot as busy in the next frame. That is, it only needs to send the BNACK message in the downlink time slot of the next frame, and then returns to the idle state.

[0069] Step 9: After the terminal A receives the last ACK check information, it ends this uplink transmission process, clears the uplink process mark, and returns to the idle state.

[0070] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature disclosed in this specification or any new combination, as well as any new method or process step disclosed or any new combination.

Claims

1. A wireless communication method, applied to a multi-terminal access system; characterized in that: include: In a multi-terminal access system, first information is used in a downlink channel to clearly indicate that an uplink time slot is occupied, so that a terminal that has not accessed the system pauses accessing the system in the uplink time slot when detecting the first information.

2. The wireless communication method according to claim 1, wherein: The using the first information in the downlink channel to clearly indicate the occupation state of the uplink time slot includes: The first information is sent in a downlink channel corresponding to a downlink time slot of a terminal allowed to access the system, so as to clearly indicate that the uplink time slot of the terminal allowed to access the system is occupied.

3. The wireless communication method according to claim 2, wherein: The first information explicitly indicates the uplink time slot occupied by the terminal allowed to access the system.

4. The wireless communication method according to claim 2 or 3, characterized in that: The sending the first information in a downlink time slot corresponding to a terminal allowed to access the system comprises: The first information is sent in all downlink time slots corresponding to all uplink time slots occupied by the terminals allowed to access the system.

5. The wireless communication method according to claim 2 or 3, characterized in that: The method of causing a terminal that has not accessed the system to suspend access to the system in the uplink time slot when detecting the first information comprises: So that when a terminal that has not accessed the system detects the first information in the downlink time slot, it stops accessing the system in the uplink time slot.

6. The wireless communication method according to claim 1, wherein: The first information is an explicit identifier, or information carried in an explicit identifier.

7. The wireless communication method according to any one of claims 1 to 3, characterized in that: The first information is invalid for the terminal allowed to access the system.

8. The wireless communication method according to claim 7, wherein: Also includes: The second information is used in a downlink channel to clearly instruct the terminal allowed to access the system, so as to instruct the terminal allowed to access the system to ignore the first information.

9. A terminal, applied to a multi-terminal access system, characterized in that: The terminal is configured as follows: Before accessing the system, it is detected whether the downlink channel contains first information, wherein the first information clearly indicates that the uplink time slot is occupied; if the first information is detected, accessing the system in the uplink time slot is suspended.

10. An access point, applied to a multi-terminal access system, characterized in that: The access point is configured as: The first information is used in the downlink channel to clearly indicate that the uplink time slot is occupied, so that a terminal that has not accessed the system will suspend accessing the system in the uplink time slot when detecting the first information.

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