FIG. 4B illustrates an example of a process performed by the node apparatus supporting the RTS/CTS mechanism according to embodiments of the disclosure.

If the PER exceeds the PER tolerance of the current data rate, the data rate may be decreased. As shown in FIG. 4B, if the PER measurement (e.g., a measured value of the PER) increases and exceeds the PER tolerance of the current data rate after the RTS/CTS is disabled, the link adaptation algorithm may reduce the data rate, that is, the link adaptation algorithm may decrease the data rate by (e.g., according to) the PER tolerance. For example, if the current node 300 transmits data at the data rate V₂, and the measured PER is greater than the PER tolerance T₂(T₁>T₂) at the data rate V₂, then the link adaptation algorithm may decrease the data rate to V₁. On the other hand, if the PER measurement decreases to be lower than the PER tolerance of adjacent higher data rate after the RTS/CTS is enabled, then the link adaptation algorithm may increase the data rate (to that higher data rate), that is, the link adaptation algorithm may increase the data rate by (e.g., according to) the PER tolerance. For example, if the current node 300 transmits data at the data rate V₂, and the measured PER acquired at this time is less than the PER tolerance T₃(T₂>T₃) at the data rate V₃, then the link adaptation algorithm may increase the data rate to V₃.

It should be understood that the descriptions of the components related to the node apparatus supporting the RTS/CTS mechanism herein are only examples and the disclosure does not limit this.

FIG. 5 illustrates a flowchart of a method for RTS/CTS adaptive enablement/disablement according to embodiments of the disclosure.

First, at operation S510, a first packet error rate is measured in a first state, wherein each of the first state and the second state corresponding to a different one of an RTS/CTS enabled state and an RTS/CTS disabled state, that is to say, the first state is one of an RTS/CTS enabled state and/or an RTS/CTS disabled state (e.g., the RTS/CTS enabled state), and the second state is the other (e.g., the RTS/CTS disabled state). In embodiments of the disclosure, the node 300 may continuously measure the packet error rate PER according to (e.g., at) a predetermined or alternatively, given time period, for example, the PER measurement component 302 in the node 300 may measure the PER at a higher frequency (shorter time period) or the PER measurement function may be always (e.g., continuously) running in real-time in the background. The node 300 may transmit a plurality packets in a predetermined or alternatively, given time period, count the number of packets that do not return an ACK, and then the PER may be calculated as the ratio of the number of packets that do not return an ACK to the total number of packets transmitted in that time period. Immediately (or promptly) afterwards, the node 300 may start the next predetermined or alternatively, given time period of PER measurement. For example, the predetermined or alternatively, given time period may be 100 ms (100 ms is only an example and the disclosure does not limit this).

In embodiments of the disclosure, a first packet error rate in the RTS/CTS disabled state may be acquired while node 300 is in the RTS/CTS disabled state, where the first packet error rate may be the most recent packet error rate acquired in the RTS/CTS disabled state after starting the present method procedure. In embodiments of the disclosure, a first packet error rate in the RTS/CTS enabled state may be acquired while the node 300 is in the RTS/CTS enabled state, where the first packet error rate may be one of a plurality of first packet error rates acquired in the RTS/CTS enabled state after starting the present method procedure.

Next, at operation S520, the first state may be changed to a second state in response to determining that the first packet error rate satisfies a (predetermined or alternatively, given) condition. The first state is the RTS/CTS disabled state, the second state is the RTS/CTS enabled state, and the condition is that the first packet error rate is greater than the threshold; or the first state is the RTS/CTS enabled state, the second state is the RTS/CTS disabled state, the first packet error rate is one of a plurality of first packet error rates, and the condition is that values of the plurality of first packet error rates remain stable or decrease. Specifically, in the case where the first state is the RTS/CTS disabled state, the RTS/CTS disabled state may be changed to the RTS/CTS enabled state in response to determining that the first packet error rate is greater than a threshold (e.g., a first threshold); in the case where the first state is the RTS/CTS enabled state, a first packet error rate being one of a plurality of first packet error rates may be acquired, and the RTS/CTS enabled state may be changed to the RTS/CTS disabled state in response to determining that the values of the plurality of first packet error rates remain stable or decrease.

In embodiments of the disclosure, the node 300 may continuously measure the packet error rate PER at a predetermined or alternatively, given time period. When the node 300 is in the RTS/CTS disabled state, a first packet error rate in the RTS/CTS disabled state may be acquired, where the first packet error rate may be a PER individual (e.g., single) measurement value in the RTS/CTS disabled state. If the PER individual measurement value increases and exceeds the threshold, it may indicate that the node 300 is in an interference environment where there are many hidden nodes and packet transmissions are conflicting, resulting in a higher data transmitting failure rate, and thus node 300 may attempt to enable RTS/CTS (changing the RTS/CTS disabled state to RTS/CTS enabled state). The threshold may be the PER predefined or alternatively, given tolerance of the current data rate (set PER tolerance value). If the PER increases and exceeds the PER predetermined (or alternatively, given) tolerance of the current data rate, the node 300 may enter the link adaptation algorithm procedure, where the data rate component 303 may reduce the data rate of the node 300. Node 300 may enable RTS/CTS in an attempt to improve the PER prior to reducing the data rate.

In embodiments of the disclosure, the node 300 may continuously measure the packet error rate PER at a predetermined or alternatively, given time period. When node 300 is in the RTS/CTS enabled state, a first packet error rate in the RTS/CTS enabled state may be acquired, where the first packet error rate may be one of a plurality of PER measurement values in the RTS/CTS enabled state. If the plurality of PER measurement values remain stable or decrease, this may indicate that node 300 is in a clean environment with fewer hidden nodes, RTS/CTS enablement may cause an increase in time (e.g., communication delay) and power consumption, and thus node 300 may attempt to disable RTS/CTS (change RTS/CTS enable state to RTS/CTS disable state). Here the plurality of PER measurement values remaining stable may refer to the plurality of PER measurements (e.g., 3 or 5, which are not limited by the present disclosure) remain the same value, a similar value, or fluctuate in a smaller range (e.g., a set range). The plurality of PER measurement values decreasing may refer to a decreasing trend of the plurality of PER measurement values.

On the other hand, in response to determining that the first packet error rate does not satisfy the (predetermined or alternatively, given) condition, the first packet error rate in the first state may be re-measured, that is to say, the first state may be maintained and the process may return to the operation of measuring the first packet error rate (see the discussion of FIGS. 6-7 for further examples of this process). Specifically, in the case where the first state is the RTS/CTS disabled state, in response to determining that the first packet error rate is less than or equal to a threshold, the RTS/CTS disabled state may be maintained and the process may return to the operation of measuring the first packet error rate; in the case where the first state is the RTS/CTS enabled state, the acquired first packet error rate may be one of a plurality of first packet error rates, in response to determining that the plurality of first packet error rates do not remain stable or decrease, the RTS/CTS enabled state may be maintained and the process may return to the operation of measuring the first packet error rate.

In embodiments of the disclosure, the first packet error rate in the RTS/CTS disabled state may be acquired when the node 300 is in the RTS/CTS disabled state, where the first packet error rate may be a PER individual measurement value in the RTS/CTS disabled state. If the PER individual measurement value is less than or equal to the threshold, where the threshold may be the predefined or alternatively, given PER tolerance of the current data rate (set PER tolerance value), the node 300 may not enter the link adaptation algorithm procedure to reduce the data rate of the node 300, and the PER measurement value may have a smaller impact on the node data rate which is still within the tolerance range. Then, the node 300 may maintain the RTS/CTS disabled state and continue to acquire the packet error rate measured in the RTS/CTS disabled state (returning to the operation of measuring the first packet error rate).

In embodiments of the disclosure, when the node 300 is in the RTS/CTS enabled state, the first packet error rate in the RTS/CTS enabled state may be acquired, where the first packet error rate may be one of a plurality of PER measurement values in the RTS/CTS enabled state. If the plurality of PER measurement values do not remain stable or decrease, then the node 300 may be in an environment that may have hidden nodes and the RTS/CTS mechanism may be useful to improve transmission. Then, the node 300 may maintain the RTS/CTS enabled state and continue to acquire the packet error rate in the RTS/CTS enabled state (returning to the operation of measuring the first packet error rate).

Next, at operation S530, a second packet error rate is measured in the second state. In embodiments of disclosure, the node 300, with the first state being the RTS/CTS disabled state, may attempt to change the RTS/CTS disabled state to the RTS/CTS enabled state to acquire the second packet error rate measured in the RTS/CTS enabled state (the second state), where the second packet error rate may be a PER individual measurement value in the RTS/CTS enabled state. In embodiments of the disclosure, the node 300, with the first state being the RTS/CTS enabled state, may attempt to change the RTS/CTS enabled state to the RTS/CTS disabled state to acquire the second packet error rate measured in the RTS/CTS disabled state (the second state), where the second packet error rate may be a PER individual measurement value in the RTS/CTS disabled state.

Then, at operation S540, node 300 may determine whether to change from the second state to the first state based on the second packet error rate and a threshold (e.g., a second threshold). According to embodiments, the second threshold may be the same as or similar to the first threshold discussed in connection with operation S520. Further, it is determined not to change from the second state to the first state based on the second packet error rate being less than the threshold. Specifically, in the case of changing the RTS/CTS disabled state to the RTS/CTS enabled state, if the second packet error rate is less than the threshold value, the RTS/CTS enabled state may be maintained; in the case of changing the RTS/CTS enabled state to the RTS/CTS disabled state, if the second packet error rate is less than the threshold, the RTS/CTS disabled state may be maintained. In addition, the first state is the RTS/CTS disabled state, the second state is the RTS/CTS enabled state, it is determined to change from the second state to the first state based on the second packet error rate being greater than or equal to the threshold. Changing from the RTS/CTS enabled state to the RTS/CTS disabled state is performed in response to the determining to change from the second state, a data rate may be reduced, and the first packet error rate may be re-measured. Or the first state is the RTS/CTS enabled state, the second state is the RTS/CTS disabled state, it is determined to change from the second state to the first state may based on the second packet error rate being greater than or equal to the threshold. Changing from the RTS/CTS disabled state to the RTS/CTS enabled state is performed in response to the determining to change from the second state, and the first packet error rate may be re-measured. Specifically, in the case of changing the RTS/CTS disabled state to the RTS/CTS enabled state, if the second packet error rate is greater than or equal to the threshold, the RTS/CTS enabled state may be changed to the RTS/CTS disabled state, the data rate may be reduced and the procedure may return to the operation of measuring the first packet error rate (e.g., operation S510); in the case of changing the RTS/CTS enabled state to the RTS/CTS disabled state, if the second packet error rate is greater than or equal to the threshold, the RTS/CTS disabled state may be changed to the RTS/CTS enabled state and the procedure may return to the operation of measuring the first packet error rate (e.g., operation S510).

In embodiments of the disclosure, the threshold involved in the comparison may be the predetermined or alternatively, given PER tolerance of the current data rate. The node 300 may attempt to change the RTS/CTS disabled state to the RTS/CTS enabled state to acquire a second packet error rate measured in the RTS/CTS enabled state, where the second packet error rate may be a PER individual measurement value in the RTS/CTS enabled state. If the second packet error rate is less than the threshold, it may indicate that the enablement of RTS/CTS mechanism has improved the packet transmission in the current environment, and the data transmission failure (or likelihood of data transmission failure) is reduced, which effectively solves (or reduces) the hidden node challenge. Then, the node 300 may maintain the RTS/CTS enabled state without reducing the data rate, which ensures (or improves) the efficiency of data transmission. However, if the second packet error rate is greater than or equal to the threshold, it may indicate that the RTS/CTS mechanism enablement is not as helpful for packet transmission in the current environment, and continuation of the enablement may only increase the delay and power consumption. Then the node 300 may change from the RTS/CTS enabled state to the RTS/CTS disabled state, and the node 300 may enter the normal link adaptation algorithm procedure, and the data rate component 303 may reduce the rate of the node 300. The node 300 may continue to acquire the packet error rate measured in the RTS/CTS disabled state (returning to the operation of measuring the first packet error rate).

In embodiments of the present disclosure, the threshold involved in the comparison may be the predetermined or alternatively, given PER tolerance of the current data rate. The node 300 may attempt to change the RTS/CTS enabled state to the RTS/CTS disabled state to acquire a second packet error rate measured in the RTS/CTS disabled state, where the second packet error rate may be a PER individual measurement value in the RTS/CTS disabled state. If the second packet error rate is less than the threshold, it may indicate that the node 300 is not interfered by the hidden node and enablement of the RTS/CTS mechanism may only increase the latency and power consumption, then the node 300 may remain in the RTS/CTS disabled state. However, if the second packet error rate is greater than or equal to the threshold, indicating that there is interference from hidden nodes in the current environment and packet transmissions are conflicting, resulting in a higher data transmitting failure rate, then the node 300 may change from the RTS/CTS disabled state to the RTS/CTS enabled state. The node 300 may continue to acquire the packet error rate measured in the RTS/CTS enabled state (returning to the operation of measuring the first packet error rate).

As described above, the method for RTS/CTS adaptive enablement/disablement according to embodiments may adaptively enable or disable RTS/CTS according to various scenarios, improving the utilization of wireless channel resources and/or increasing network communication throughput while reducing communication conflicts.

The flowchart of adaptively enabling RTS/CTS when the initial state is RTS/CTS disabled state will be illustrated in detail below with reference to FIG. 6, and the flowchart of adaptively disabling RTS/CTS when the initial state is RTS/CTS enabled state will be illustrated in detail with reference to FIG. 7. According to embodiments, the method of setting the initial state of node 300 may include, but is not limited to, the following cases:

- 1) Direct setting, in which the initial state of node 300 may be set directly to the RTS/CTS disable state or the RTS/CTS enable state.
- 2) Setting based on the measured RSSI value, in which the initial state of node 300 may be set based on the measured RSSI of the received signal. For example, if the RSSI is greater than a certain threshold, the initial state of node 300 is set to RTS/CTS disabled state, otherwise it is set to RTS/CTS enabled state.
- 3) Setting based on the packet size. For example, if the packet size of the packet to be transmitted by node 300 is less than a certain threshold, the initial state is set to RTS/CTS disabled state, otherwise it is set to RTS/CTS enabled state.

FIG. 6 illustrates a flowchart of adaptively enabling RTS/CTS in the RTS/CTS disabled state according to embodiments of the disclosure, as shown in FIG. 6.

Operation 0: RTS/CTS disable state. At this time, the node 300 may transmit data without RTS/CTS protection and conflicts in data transmission may occur. According to embodiments, the procedure discussed in connection with FIG. 6 may refer to a procedure performed by the node 300 in a scenario in which one or more packets to be transmitted are smaller in size (e.g., smaller than an RTS/CTS threshold size), and thus, the node 300 is initially in the RTS/CTS disable state.

- Operation 1: Acquire the real-time measured PER in the RTS/CTS disabled state. The node 300 may measure the packet error rate PER in real time (with a predetermined or alternatively, given time period), and the PER measurement function of the node 300 may always run in the background. At this time, the node may acquire the real-time measured PER in the RTS/CTS disabled state, and the PER may be a single PER.
- Operation 2: Determine whether the PER is greater than the predetermined or alternatively, given PER tolerance of the current data rate (e.g., a first threshold). If so (“yes”), this may indicate that the node 300 is in an interference environment where there are many hidden nodes, resulting in a high data transmitting failure rate. The node 300 may enter the link adaptation algorithm procedure to reduce the rate of the node 300 by the data rate component 303. And the procedure may advance to operation 3 before entering the link adaptation algorithm. If not (“no”), the PER measurement value at this time may have a small impact on the node data rate which is still within the tolerance range, and the node 300 may remain in the RTS/CTS disabled state. Or, if the PER has only increased but is not yet greater than the PER tolerance for the current data rate, the data rate of the node may not be reduced. The impact of the PER on the data rate is still smaller and the RTS/CTS mechanism may not be enabled, and thus the procedure may return to operation 1 to continue to acquire the PER measured in the RTS/CTS disabled state.
- Operation 3: Enable the RTS/CTS mechanism. The node may change from the RTS/CTS disabled state to the RTS/CTS enabled state.
- Operation 4: Acquire the new PER in the RTS/CTS enabled state. Since the node 300 measures the packet error rate PER in real time (with a predetermined or alternatively, given time period), the PER measurement function of node 300 may always run in the background. At this point, the node may acquire the new PER in the RTS/CTS enabled state.
- Operation 5: Determine whether the new PER is less than the predetermined or alternatively, given PER tolerance of the current data rate (e.g., a second threshold). If so (“yes”), it may indicate that the RTS/CTS mechanism has effectively reduced the data transmission failure and solved (or mitigated) the hidden node challenge, and the procedure may advance to operation 6. If not (“no”), that is, the new PER is greater than or equal to the predefined (or alternatively, given) PER tolerance of the current data rate, it may indicate that the RTS/CTS mechanism is not sufficiently helpful for the packet transmission in the current environment, and continuation of enablement may only increase the latency and power consumption, then the procedure may advance to operation 7. According to embodiments, the first threshold and the second threshold may be the same or similar (both the first threshold and the second threshold may be referred to herein as the PER threshold). The node 300 may store a table (see, e.g., Table 1 above) in a memory (such as the at least one memory 910 discussed below), the table indicating associations between data rates (e.g., data rate limits, data rate intervals, etc.) and corresponding PER tolerances (e.g., PER tolerance limits, PER tolerance intervals, etc.). To determine the PER threshold, the node 300 may determine the data rate in the table corresponding to the current data rate of the node 300 and determine the PER tolerance associated with the determined data rate. The PER threshold may correspond to (e.g., be equal to) the determined PER tolerance.
- Operation 6: Maintain the RTS/CTS enabled state. At this point, the node 300 may enter the RTS/CTS enabled state, and subsequent data transmission may be under RTS/CTS protection. According to embodiments, the node 300 may generate and/or transmit data (e.g., a data frame) to another device (e.g., a mobile device, access point, etc.) in the RTS/CTS enabled state in operation 6. And the node 300 may transfer to the procedure of FIG. 7 below.
- Operation 7: Disable the RTS/CTS mechanism. Subsequent data transmission may not be under RTS/CTS protection as the initial state.
- Operation 8: Reduce the data rate. The node 300 may disable the RTS/CTS mechanism. Since the PER in the RTS/CTS disabled state may exceed the threshold, the node 300 may enter the normal link adaptation algorithm procedure and the data rate component 303 may reduce the data rate of the node 300. At this point, the node state may be the same as (or similar to) the initial state and the procedure may returns to operation 1 again to acquire the PER measured in the RTS/CTS disabled state, and the entire procedure may become a loop. According to embodiments, the node 300 may generate and/or transmit data (e.g., a data frame) to another device (e.g., a mobile device, access point, etc.) in the RTS/CTS disabled state in operation 8.

As described above, the method for RTS/CTS adaptive enablement according to embodiments may adaptively enable RTS/CTS according to various scenarios, improving the utilization of wireless channel resources and/or increasing network communication throughput while reducing communication conflicts.

FIG. 7 illustrates a flowchart of adaptively disabling RTS/CTS in the RTS/CTS enabled state according to embodiments of the disclosure.

- Operation 0: RTS/CTS enabled state. At this point, the node 300 may transmit data with RTS/CTS protection. According to embodiments, the procedure discussed in connection with FIG. 7 may refer to a procedure performed in a scenario in which one or more packets to be transmitted are larger in size (e.g., larger than an RTS/CTS threshold size), and thus, the node 300 is initially in the RTS/CTS enable state.
- Operation 1: Acquire the PER measured in real time in the RTS/CTS enabled state. The node 300 may measure the packet error rate PER in real time (with a predetermined or alternatively, given time period), and the PER measurement function of node 300 may always run in the background. At this time, the node may acquire a plurality of PERs measured in real time in the RTS/CTS enabled state.
- Operation 2: Determine whether the PER value remains stable or decreases. Here, that the node 300 may periodically check whether the PER measurement results remain stable or decrease, and the interval of the periodic checks may be set as desired, for example, it may be set to a longer interval. It may be determined whether the PER has remained stable or decreased over a recent period of time based on the plurality of PER values acquired. If so (“yes”), it may indicate that node 300 may be in a clean environment with fewer hidden nodes, while avoiding PER jitter (variation between large and small) caused by environmental factors which may cause misjudgment in subsequent operations, and the procedure may advance to operation 3. If not (“no”), the node 300 may be in an environment having hidden nodes, while PER jitter may cause misjudgment in subsequent operations, and thus the procedure may return to operation 1 to continue acquiring the PER measured in the RTS/CTS enabled state.
- Operation 3: Disable the RTS/CTS mechanism. The node may change from the RTS/CTS enabled state to the RTS/CTS disabled state.
- Operation 4: Acquiring the new PER in the RTS/CTS disabled state. Since the node 300 may measure the packet error rate PER in real time (with a predetermined or alternatively given time period), the PER measurement function of node 300 may always run in the background. At this point, the node may acquire the new PER in the RTS/CTS disabled state.
- Operation 5: Determine whether the new PER is greater than or equal to the predetermined (or alternatively, given) PER tolerance of the current data rate (e.g., a PER threshold). If not (“no”), it may indicate that node 300 is not interfered with by hidden nodes and enabling the RTS/CTS mechanism may only increase the latency and power consumption, and the procedure may advance to operation 6. If yes (“yes”), it may indicate that there is interference from hidden nodes in the current environment and packet transmission is in conflict, resulting in a higher failure rate of data transmission, and the procedure may advance to operation 7. According to embodiments, the node 300 may store a table (see, e.g., Table 1 above) in a memory (such as the at least one memory 910 discussed below), the table indicating associations between data rates (e.g., data rate limits, data rate intervals, etc.) and corresponding PER tolerances (e.g., PER tolerance limits, PER tolerance intervals, etc.). To determine the PER threshold, the node 300 may determine the data rate in the table corresponding to the current data rate of the node 300 and determine the PER tolerance associated with the determined data rate. The PER threshold may correspond to (e.g., be equal to) the determined PER tolerance.
- Operation 6: Maintain the RTS/CTS disabled state. At this point, the node 300 may enter the RTS/CTS disabled state and the subsequent data transmission may not have RTS/CTS protection. According to embodiments, the node 300 may generate and/or transmit data (e.g., a data frame) to another device (e.g., a mobile device, access point, etc.) in the RTS/CTS disabled state in operation 6. And the node 300 may transfer to the procedure of FIG. 6 described above.
- Operation 7: Enable the RTS/CTS mechanism. The subsequent data transmission may be under RTS/CTS protection, at which point the node state is the same as (or similar to) the initial state. The procedure may return to operation 1 again to acquire the PER measured in the RTS/CTS enabled state, and the entire procedure may become a loop. According to embodiments, the node 300 may generate and/or transmit data (e.g., a data frame) to another device (e.g., a mobile device, access point, etc.) in the RTS/CTS enabled state in operation 7.

As described above, the method for RTS/CTS adaptive disablement according to embodiments may adaptively disable RTS/CTS according to various scenarios, improving the utilization of wireless channel resources and/or increasing network communication throughput while reducing communication conflicts.

FIG. 8 illustrates a block diagram of a device for RTS/CTS adaptive enablement/disablement according to embodiments of the disclosure.

As shown in FIG. 8, a device 800 (e.g., may be implemented using, or used to implement, the node 300) for RTS/CTS adaptive enablement/disablement may comprise: a first acquisition module 810, a state changing module 820, a second acquisition module 830 and/or a state determination module 840, wherein the first acquisition module 810 may acquire a first packet error rate measured in a first state; the state changing module