WO2017114032A1 - 一种基于空间重用的退避方法及设备 - Google Patents

一种基于空间重用的退避方法及设备 Download PDF

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Publication number
WO2017114032A1
WO2017114032A1 PCT/CN2016/106983 CN2016106983W WO2017114032A1 WO 2017114032 A1 WO2017114032 A1 WO 2017114032A1 CN 2016106983 W CN2016106983 W CN 2016106983W WO 2017114032 A1 WO2017114032 A1 WO 2017114032A1
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ppdu
backoff
channel
station
time interval
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PCT/CN2016/106983
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English (en)
French (fr)
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范巍巍
罗俊
庞继勇
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华为技术有限公司
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H04W74/0841—Random access procedures, e.g. with 4-step access with collision treatment
    • H04W74/085—Random access procedures, e.g. with 4-step access with collision treatment collision avoidance
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H04W74/0816—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA] with collision avoidance

Definitions

  • the present invention relates to the field of wireless communication technologies, and in particular, to a backoff method and device based on spatial reuse.
  • STA1 is associated with an AP (Wireless Access Point)
  • STA2 and STA3 are associated with AP2
  • STA1 and STA2 are mutually
  • the site of the OBSS (Overlapping Basic Service Set) when there is a PPDU (PLCP Protocol data unit) transmission between STA1 and AP1, the received signal strength in the range 100 is -72dBm.
  • the received signal strength at the range 101 is -82 dBm. It is assumed that the PPDU monitoring threshold of STA2 and STA3 is -82 dBm.
  • STA2 When STA2 detects the PPDU during the backoff, its backoff mechanism is as shown in Figure 2a, due to the received signal strength. STA2 is greater than the PPDU monitoring threshold. STA2 suspends the backoff process. After waiting for the OBSS PPDU transmission to complete, it passes through a DIFS (Distributed Inter-frame Spacing) duration, and after the channel remains idle, STA2 continues unfinished evacuation. Procedure; or when STA2 detects a PPDU during channel monitoring in DIFS, its backoff mechanism is as shown in FIG.
  • DIFS Distributed Inter-frame Spacing
  • STA2 suspends the channel monitoring process corresponding to DIFS, After waiting for the transmission of the OBSS PPDU, after a DIFS duration, and the channel remains idle, STA2 randomly selects a backoff duration according to the contention window and performs a new backoff procedure.
  • the IEEE 802.11 Working Group established the High Efficiency WLAN Study Group (HEW SG) in 2013, which was completed in 2014.
  • HEW SG High Efficiency WLAN Study Group
  • TGax 802.11ax Working Group
  • the 802.11ax protocol proposes the use of spatial multiplexing in dense environments to improve network throughput and space reuse efficiency.
  • STA2 determines that the PPDU is an OBSS PPDU. After a DIFS duration, the UE retreats.
  • the contention channel that is, STA2 needs to pass at least one PPDU after listening to the PPDU.
  • the preamble duration plus a DIFS duration is backed up to compete for the channel.
  • the STA3 After the STA3 detects the PPDU in the backoff process, the received signal strength of the PPDU is smaller than the PPDU monitoring threshold. Therefore, the STA3 continues to perform the backoff. If the STA3 is idle during the backoff process, the channel may be idle. send data.
  • the backoff mechanism of FIG. 3 improves the efficiency of spatial reuse to some extent with respect to the backoff mechanism of FIG. 2a and FIG. 2b, the time taken before the backoff is longer and the space reuse efficiency is lower than that of the STA3.
  • the invention provides a method and a device for retreating based on space reuse, which solves the problem of low space reuse efficiency in the prior art.
  • a method for backoff based on spatial reuse including:
  • the first station detects that there is a physical layer protocol data unit PPDU transmission in the channel during the channel monitoring process;
  • the first station After determining that the received signal strength of the intercepted PPDU is not less than the first monitoring threshold, the first station stops the channel monitoring process, and demodulates the PPDU to obtain first data; the first monitoring threshold And monitoring, by the first station, a PPDU used by the first station in the channel monitoring process; the first data includes cell indication information carried by a signaling field of the PPDU and/or address information in a medium access control MAC field;
  • the second monitoring gate is used in the first time interval after the first data is obtained.
  • the threshold is a PPDU monitoring threshold of the first station in the subsequent channel monitoring process, the second monitoring threshold is greater than the first monitoring threshold, and the first time interval is less than a distributed interframe spacing. DIFS;
  • the first station performs backoff after the first time interval
  • the first station starts transmitting data if the channel is in an idle state after the backoff is completed.
  • the channel monitoring process is a channel monitoring process in a point interframe space PIFS or DIFS or an extended interframe space EIFS or an arbitration interframe space AIFS
  • the first time interval includes at least one delay D1 for transmitting the first data from the physical layer to the MAC layer, and at least one delay M1 for processing the first data by the MAC layer, and performing at least one channel evaluation
  • the length of time required for CCA testing is CCAdel;
  • the first station performs backoff after the first time interval, including:
  • the first station After determining, in the first time interval, that the channel is in an idle state, the first station performs backoff after the first time interval.
  • the first site performs backoff, including:
  • the first station determines the backoff duration CW1 used by the backoff process according to the number of active sites or the number of active sites of the SR; the CW1 satisfies the following formula:
  • N sta represents a weighted average of the number of the active SR sites or the number of the active sites
  • the active SR site is a site that is an OBSS with the first site
  • the active site is the A site can frame the site where the PPDU is heard.
  • the first time interval includes at least one D1 and at least one M1 .
  • the first station performs backoff, including:
  • the first station performs backoff according to the remaining backoff duration.
  • the first station performs backoff, including:
  • the first station adjusts the remaining backoff duration according to the received signal strength of the PPDU, to obtain a new backoff duration
  • the first station performs backoff according to a new backoff duration
  • New_BO Remaining_BO* ⁇
  • New_BO is the new backoff duration
  • Remaining_BO is the remaining backoff duration, where 0 ⁇ 1, and ⁇ is proportional to the received signal strength of the PPDU.
  • the SRIFS includes a D1, an M1, and a duration CCAdel required to perform a channel evaluation CCA test;
  • the first station determines, in the first time interval, that the PPDU is the OBSS PPDU, and the second monitoring threshold is used as a PPDU monitoring threshold of the first station in the subsequent channel monitoring process, including:
  • the second monitoring threshold is used as the PPDU monitoring threshold of the first station in the subsequent channel monitoring process
  • Determining, by the first station, that the channel is in an idle state during the first time interval including:
  • the first station determines that the channel is in an idle state in the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the first time interval is a PIFS
  • the first station determines, in the first time interval, that the PPDU is the OBSS PPDU, and the second monitoring threshold is used as a PPDU monitoring threshold of the first station in a subsequent channel monitoring process, including:
  • Determining, by the first station, that the channel is in an idle state during the first time interval including:
  • the first station determines that the channel is in an idle state in the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • a space reuse-based backoff device is characterized by comprising:
  • a transceiver module configured to detect a physical layer protocol data unit PPDU transmission in the channel during channel monitoring
  • a processing module configured to: after determining that the received signal strength of the intercepted PPDU is not less than a first monitoring threshold, suspending the channel monitoring process, and demodulating the PPDU to obtain first data; the first monitoring threshold And a PPDU monitoring threshold used by the device in the channel monitoring process; the first data includes cell indication information carried by a signaling field of the PPDU and/or address information in a media access control MAC field;
  • the processing module is further configured to: if the first time after the first data is obtained, if Determining, according to the first data, that the PPDU is an overlapping basic service set OBSS PPDU, and using a second monitoring threshold as a PPDU monitoring threshold of the device in a subsequent channel monitoring process, where the second monitoring threshold is The first time interval is greater than the first monitoring threshold, the first time interval is less than one distributed interframe space DIFS; and the backing is performed after the first time interval;
  • the transceiver module is further configured to start sending data if the channel is in an idle state after the backoff is completed.
  • the channel monitoring process is a channel monitoring process in a point interframe space PIFS or DIFS or an extended interframe space EIFS or an arbitration interframe space AIFS
  • the first time interval includes at least one delay D1 for transmitting the first data from the physical layer to the MAC layer, and at least one delay M1 for processing the first data by the MAC layer, and performing at least one channel evaluation
  • the length of time required for CCA testing is CCAdel;
  • the processing module is configured to:
  • backoff is performed after the first time interval.
  • the processing module is configured to:
  • N sta represents a weighted average of the number of active SR sites or the number of the active sites, the active SR site being a site that is OBSS with the device, and the active site is a frame capable of the device The site where the PPDU was heard.
  • the first time interval includes at least one D1 and at least one M1 .
  • the processing module is configured to:
  • the processing module is configured to:
  • Determining a remaining backoff duration according to the suspension time of the channel monitoring process Determining a remaining backoff duration according to the suspension time of the channel monitoring process; adjusting the remaining backoff duration according to the received signal strength of the PPDU to obtain a new backoff duration; and performing backoff according to the new backoff duration;
  • New_BO Remaining_BO* ⁇
  • New_BO is the new backoff duration
  • Remaining_BO is the remaining backoff duration, where 0 ⁇ 1, and ⁇ is proportional to the received signal strength of the PPDU.
  • the SRIFS includes a D1, an M1, and a duration CCAdel required to perform a channel evaluation CCA test;
  • the processing module is configured to include:
  • the processing module is configured to:
  • the channel is determined to be in an idle state within the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the first time interval is a PIFS
  • the processing module is configured to:
  • the processing module is configured to:
  • the channel is determined to be in an idle state within the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • the backoff is performed after the first time interval, and the first time interval is less than a distributed interframe space DIFS, thereby reducing the backoff The time interval, so that the station can enter the backoff process faster, and the PPDU monitoring threshold in the subsequent channel monitoring process is improved, further reducing the waiting time before the station sends data, thereby greatly improving the efficiency of space reuse.
  • 1 is a scenario diagram of a station contention channel in a WLAN system
  • 2a is a schematic diagram of a backoff mechanism in the prior art
  • 2b is a schematic diagram of a backoff mechanism in the prior art
  • FIG. 3 is a schematic diagram of a backoff mechanism in the prior art
  • FIG. 4 is a schematic diagram of an application scenario according to an embodiment of the present invention.
  • Figure 5 is a schematic diagram of a DIFS structure
  • FIG. 6 is a schematic flowchart of a backoff method based on spatial reuse according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a backoff mechanism according to an embodiment of the present invention.
  • FIG. 8 is a schematic flowchart of a backoff method based on spatial reuse according to an embodiment of the present invention.
  • FIG. 9 is a schematic structural diagram of a PPDU frame in 802.11ax.
  • FIG. 10 is a schematic structural diagram of an SRIFS according to an embodiment of the present invention.
  • FIG. 11 is a schematic diagram of a backoff mechanism according to an embodiment of the present invention.
  • FIG. 12 is a schematic flowchart of a backoff method based on spatial reuse according to an embodiment of the present invention.
  • FIG. 13 is a schematic diagram of a backoff mechanism according to an embodiment of the present invention.
  • FIG. 14 is a schematic flowchart of a backoff method based on spatial reuse according to an embodiment of the present invention.
  • FIG. 15 is a schematic diagram of a backoff device based on space reuse according to an embodiment of the present invention.
  • FIG. 16 is a schematic structural diagram of a hardware structure of a backoff device based on spatial reuse according to an embodiment of the present invention.
  • a first site is associated with AP1
  • a second site is associated with AP2
  • a first site and a second site are sites that are OBSSs, wherein the first site and the AP1 are
  • the transmission of the PPDU is in progress, the received signal strength in the range 400 is -72 dBm, and the first monitoring threshold of the first station is -82 dBm, if the space is reused after the PPDU is detected in the first station channel monitoring process.
  • the first time interval is SRIFS (Spatial Reuse Inter-Frame Space)
  • SRIFS Spatial Reuse Inter-Frame Space
  • the backoff mechanism of a site can also be applied to DIFS or PIFS (Piont Inter-Frame Space) or EIFS (Extended Inter-frame Space) or AIFS (Arbitration Inter-Frame Space).
  • DIFS Session Inter-Frame Space
  • PIFS Peripheral Inter-Frame Space
  • EIFS Extended Inter-frame Space
  • AIFS Aribitration Inter-Frame Space
  • the PIFS includes a SIFS (Short Inter-Frame Space) and a Slot Time, where the SIFS includes one D1, one M1, and one Rx/Tx, and one Slot Time includes one.
  • D2 a CCAdel, an M2, an Rx/Tx, DIFS as shown in Figure 5, including a PIFS and a Slot Time.
  • the EIFS includes one SIFS, one ACKTxTime, and one DIFS; the AIFS includes one SIFS and AIFSSN Slot Time.
  • D1 is a delay for transmitting the first data from the physical layer to the MAC layer
  • M1 is a delay in which the MAC layer processes the first data
  • Rx/Tx is the RF circuit receiving/transmitting conversion time
  • D2 is the maximum transmission delay of the D1 and WiFi signals
  • M2 is the same as M1, which is the delay for the MAC layer to process the first data.
  • ACKTxTime is the length of time during which the control frame ACK is transmitted at the lowest required rate
  • AIFSSN is the value corresponding to the category of channel access.
  • the method for backoff based on spatial reuse in the embodiment of the present invention includes:
  • Step 600 The first station detects that there is a physical layer protocol data unit PPDU transmission in the channel during the channel monitoring process;
  • Step 601 After determining that the received signal strength of the detected PPDU is not less than the first monitoring threshold, the first station stops the channel monitoring process, and demodulates the PPDU to obtain the first data.
  • the first monitoring threshold is the first station in the channel monitoring.
  • the PPDU monitoring threshold used in the process; the first data includes cell indication information carried by the signaling field of the PPDU and/or address information in the MAC field of the medium access control;
  • Step 602 The first station determines, according to the first data, that the PPDU is an overlapping basic service set OBSS PPDU according to the first data, in the first time interval after the first data is obtained, the second monitoring threshold is used as the first a PPDU monitoring threshold of a station in a subsequent channel monitoring process, the second monitoring threshold is greater than the first monitoring threshold, and the first time interval is less than a distributed interframe spacing DIFS;
  • Step 603 The first station performs backoff after the first time interval.
  • Step 604 The first station starts to send data if the channel is in an idle state after the backoff is completed.
  • the first station detects the PPDU transmission in the channel during the channel monitoring process in the backoff process.
  • the space reuse based backoff method includes:
  • Step 800 The first station detects that there is PPDU transmission in the channel during the channel monitoring process in the backoff process;
  • Step 801 the first station determines whether the received signal strength of the PPDU is not less than the first monitoring threshold of the first station, and if so, step 802 is performed; otherwise, step 803 is performed;
  • the first monitoring threshold is a PPDU monitoring threshold used by the first station in the channel monitoring process.
  • the first monitoring threshold is a traditional PPDU monitoring threshold.
  • Step 802 the first station stops the channel monitoring process in the backoff process, and performs step 804;
  • Step 803 The first station continues the channel monitoring process in the backoff process, and the process ends.
  • Step 804 The first station demodulates the PPDU to obtain first data.
  • the signaling field carrying the cell indication information is HE-SIG-A (High Efficiency Signal Frame A), specifically, the PPDU frame in the 802.11ax protocol.
  • the structure is as shown in FIG. 9.
  • the first station demodulates the HE-SIG-A in the PPDU, the first station obtains the first data, where the first data includes the cell indication information carried on the HE-SIG-A.
  • the cell indication information carried on the HE-SIG-A is the BSS identification information, and specifically, the BSS identification information is a BSS color value; or
  • the first station obtains the first data when the PPDU is demodulated to the MAC header in the PPDU, where the first data includes the address information in the MAC field, and the address information of the specific MAC field includes the cell where the first station is located. BSSID.
  • Step 805 the first station determines whether the PPDU is an OBSS PPDU according to the first data, and if so, step 806 is performed, otherwise step 807 is performed;
  • the PPDU is not an OBSS PPDU, if the BSS If the color value is not equal to the BSS color value of the cell where the first station is located, the PPDU is an OBSS PPDU;
  • the PPDU is not an OBSS PPDU.
  • the BSSID in the address information is different from the BSSID corresponding to the cell where the first station is located, and the PPDU is an OBSS PPDU.
  • Step 806 The first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process, where the second monitoring threshold is greater than the first To monitor the threshold, go to step 808.
  • the package The delay D1 of transmitting a first data from the physical layer to the MAC layer, the delay M1 of processing the first data by a MAC layer, and the duration CCAdel required for performing a channel idle detection;
  • the first time interval is PIFS, such as As shown in FIG. 5, an SIFS and a Slot Time are included, wherein one SIFS includes one D1, one M1, one Rx/Tx, and one Slot Time, wherein one Slot Time includes one D2, one CCAdel, one M2, and one Rx/Tx.
  • D2 is the maximum transmission delay of the D1 and WiFi signals
  • Rx/Tx is the RF circuit receiving/transmitting conversion time
  • the first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process in the first time interval D1 and M1, and the second monitoring threshold is greater than the first monitoring threshold. Then, step 808 is performed.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • the first station determines whether the PPDU is an OBSS PPDU according to the first data in D1 and M1 of the first time interval.
  • Step 807 The first station updates the NAV according to the duration of the duration in the PPDU, and the data transmission delay is performed.
  • the NAV is set to the duration of the duration, and if the duration of the duration is not greater than the value set by the current NAV, the setting of the NAV is maintained.
  • Step 808 The first station determines whether the received signal strength of the PPDU is less than the second monitoring threshold. If yes, step 809 is performed; otherwise, step 811 is performed.
  • Step 809 The first station determines that the channel is in an idle state, and then performs backoff after the first time interval.
  • performing backoff after the first time interval after obtaining the first data includes two backoff schemes, one of which is: the first station determines the remaining backoff duration according to the suspension time of the channel monitoring process; according to the remaining backoff Time to retreat;
  • the other method is: the first station determines the remaining backoff duration according to the pause time of the channel monitoring process; adjusts the remaining backoff duration according to the received signal strength of the PPDU, obtains a new backoff duration, and performs backoff according to the new backoff duration;
  • the back-off duration meets the following formula:
  • New_BO Remaining_BO* ⁇
  • New_BO is the new backoff duration
  • Remaining_BO is the remaining backoff duration, where 0 ⁇ 1, and ⁇ is proportional to the received signal strength of the PPDU.
  • the backoff duration is shortened, thereby further reducing the waiting time before the first station transmits data, thereby improving the efficiency of spatial reuse.
  • Step 810 The first station starts to send data if the channel is in an idle state after the backoff is completed.
  • Step 811 The first station updates the NAV according to the duration of the duration in the PPDU, and delays the time of sending the data. The process ends.
  • the length of the first data is a preamble duration. Therefore, after the PPDU is detected, only one preamble duration plus one SRIFS or one PIFS is needed to perform the backoff, and the SRIFS and the PIFS are performed.
  • the duration is less than DIFS, thus reducing the length of time to enter the backoff process, further reducing the waiting time before the station sends data, so that the station can enter the backoff process faster, and because the PPDU monitoring threshold in the subsequent channel monitoring process is improved, The waiting time before the station sends data is further reduced, thereby greatly improving the efficiency of space reuse.
  • the first station detects the PPDU transmission in the channel during the channel monitoring process in the backoff process.
  • the space reuse-based backoff method includes:
  • Step 1200 The first station detects that there is PPDU transmission in the channel during the channel monitoring process in the backoff process;
  • Step 1201 the first station determines whether the received signal strength of the detected PPDU is not less than the first monitoring threshold of the first station, and if so, step 1202, otherwise step 1203;
  • the first monitoring threshold is a PPDU monitoring threshold used by the first station in the channel monitoring process.
  • the first monitoring threshold is a traditional PPDU monitoring threshold.
  • Step 1202 the first station stops the channel monitoring process in the backoff process, and performs step 1204;
  • Step 1203 The first station continues the channel monitoring process in the backoff process, and the process ends.
  • Step 1204 The first station demodulates the PPDU to obtain first data.
  • the signaling field carrying the cell indication information is HE-SIG-A.
  • the PPDU frame structure format in the 802.11ax protocol is as shown in FIG. 8
  • the first station is the PPDU.
  • the first data is obtained, where the first data includes the cell indication information carried on the HE-SIG-A, where the cell indication information carried on the HE-SIG-A is BSS identification information, specifically, the BSS identification information is a BSS color value; or
  • the first station When the first station demodulates the MAC header into the PPDU, the first station obtains the first data, where the first data includes the address information in the MAC field, and the address information of the specific MAC field is the cell where the first station is located. BSSID.
  • Step 1205 the first station determines whether the PPDU is an OBSS PPDU according to the first data, and if yes, step 1206 is performed; otherwise, step 1209 is performed;
  • the PPDU is not an OBSS PPDU, if the BSS If the color value is not equal to the BSS color value of the cell where the first station is located, the PPDU is an OBSS PPDU;
  • the PPDU is not an OBSS PPDU, and the BSSID in the address information and the cell where the first station is located If the corresponding BSSID is different, the PPDU is an OBSS PPDU.
  • Step 1206 The first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process, where the second monitoring threshold is greater than the first monitoring threshold. .
  • the first time interval includes a delay M1 of the first data transmitted from the physical layer to the MAC layer and a delay D1 of the first data transmitted from the physical layer to the MAC layer.
  • the first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process in the first time interval D1 and M1.
  • the first station determines whether the PPDU is an OBSS PPDU according to the first data in the first time interval D1 and M1.
  • Step 1207 The first station adopts a second monitoring threshold, and after the first time interval after obtaining the first data, performs backoff.
  • Step 1208 The first station starts to send data if the channel is in an idle state after the backoff is completed.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • performing backoff after the first time interval after obtaining the first data includes two backoff schemes, one of which is: the first station determines the remaining backoff duration according to the suspension time of the channel monitoring process; according to the remaining backoff Time to retreat;
  • the other method is: the first station determines the remaining backoff duration according to the pause time of the channel monitoring process; adjusts the remaining backoff duration according to the received signal strength of the PPDU, obtains a new backoff duration, and performs backoff according to the new backoff duration;
  • the back-off duration meets the following formula:
  • New_BO Remaining_BO* ⁇
  • New_BO is the new backoff duration
  • Remaining_BO is the remaining backoff duration, where 0 ⁇ 1, and ⁇ is proportional to the received signal strength of the PPDU.
  • the backoff duration is shortened, thereby further reducing the waiting time before the first station transmits data, thereby improving the efficiency of spatial reuse.
  • Step 1209 The first station updates the NAV according to the duration of the duration in the PPDU, and the data transmission delay is performed.
  • the NAV is set to the duration of the duration, and if the duration of the duration is not greater than the value set by the current NAV, the setting of the NAV is maintained.
  • the time for obtaining the first data is a preamble duration. Therefore, after the PPDU is detected, only one preamble duration is required to add a duration of D1 and M1, and the durations of D1 and M1 are smaller than DIFS. , thus reducing the length of time to enter the backoff process, The step reduces the waiting time before the station sends data, so that the station can enter the backoff process faster, and the PPDU monitoring threshold in the subsequent channel monitoring process is improved, thereby further reducing the waiting time before the station sends data, thereby greatly improving The efficiency of space reuse.
  • the first station detects the PPDU transmission in the channel during the channel monitoring process, wherein the channel monitoring process is a channel monitoring process in PIFS or DIFS or EIFS or AIFS, as shown in FIG. 14, according to the backoff shown in FIG. Mechanisms, backoff methods based on spatial reuse, including:
  • Step 1400 The first station detects that there is PPDU transmission in the channel during the channel monitoring process
  • Step 1401 the first station determines whether the received signal strength of the PPDU is not less than the first monitoring threshold of the first station, and if so, step 1402, otherwise step 1403;
  • the first monitoring threshold is a PPDU monitoring threshold used by the first station in the channel monitoring process.
  • the first monitoring threshold is a traditional PPDU monitoring threshold.
  • Step 1402 the first station stops the channel monitoring process, and performs step 1404;
  • Step 1403 The first station continues the channel monitoring process, and the process ends.
  • Step 1404 the first station demodulates the PPDU to obtain first data.
  • the signaling field carrying the cell indication information is HE-SIG-A.
  • the PPDU frame structure format in the 802.11ax protocol is as shown in FIG. 9, and the first station is the PPDU.
  • the first data is obtained, where the first data includes the cell indication information carried on the HE-SIG-A, where the cell indication information carried on the HE-SIG-A is BSS identification information, specifically, the BSS identification information is a BSS color value; or
  • the first station obtains the first data when the PPDU is demodulated to the MAC header in the PPDU, where the first data includes the address information in the MAC field, and the address information of the specific MAC field includes the cell where the first station is located. BSSID.
  • Step 1405 the first station determines whether the PPDU is an OBSS PPDU according to the first data, and if yes, step 1406 is performed; otherwise, step 1407 is performed;
  • the PPDU is not an OBSS.
  • the PPDU if the BSS color value is not equal to the BSS color value of the cell where the first station is located, the PPDU is an OBSS PPDU;
  • the PPDU is not an OBSS PPDU. If the BSSID in the address information is different from the BSSID corresponding to the cell where the first station is located, the PPDU is an OBSS PPDU.
  • BSS ID Basic Service Set Identification
  • Step 1406 The first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process, where the second monitoring threshold is greater than the first. Monitoring threshold;
  • one SIFS includes one D1, one M1, one Rx/Tx, and one Slot Time
  • one of the Slot Time includes a D2, a CCAdel, an M2 and an Rx/Tx, where D2 is the maximum transmission delay of the D1 and WiFi signals, and Rx/Tx is the RF circuit reception/transmission conversion time.
  • the first station uses the second monitoring threshold as the monitoring threshold of the first station in the subsequent channel monitoring process in the first time interval D1 and M1, and the second monitoring threshold is greater than the first monitoring threshold. Then, step 1408 is performed.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • the first station determines whether the PPDU is an OBSS PPDU according to the first data in D1 and M1 of the first time interval.
  • Step 1407 Update the NAV according to the duration of the duration in the PPDU, and delay the data transmission.
  • the NAV is set to the duration of the duration, and if the duration of the duration is not greater than the value set by the current NAV, the setting of the NAV is maintained.
  • Step 1408 the first station determines whether the received signal strength of the PPDU is smaller than the second monitoring gate. If yes, go to step 1409, otherwise go to step 1411.
  • Step 1409 the first station determines that the channel is in an idle state, and then performs backoff after the first time interval after the first data is obtained.
  • performing backoff after the first time interval after obtaining the first data includes three schemes:
  • the backoff duration is shortened, thereby further reducing the waiting time before the first station transmits data, thereby improving the efficiency of spatial reuse.
  • the second type the first station performs backoff according to the backoff duration randomly selected by the current contention window. Specifically, the first station randomly selects a backoff duration CW1 from the current contention window set of ⁇ 0, CWmin ⁇ to perform backoff. ;
  • the third type the first station re-uses the number of SR sites based on the number of active sites or the active space, determines the backoff duration CW1 used in the backoff process, and performs backoff according to the backoff duration CW1;
  • N sta represents a weighted average of the number of active SR sites or the number of active sites.
  • the active SR site is a site that is OBSS with the first site, and the first site can frame the PPDU of the site, and the active site is The first site is able to frame the site where the PPDU is heard.
  • the first station receives the broadcast of multiple BSSs to collect the number of active sites or the number of active SR sites of multiple BSSs; wherein the number of active sites or active SR sites of the BSS is broadcast by the AP through Beacon or other management frames. To the first stop;
  • the first station weights the number of active sites or the number of active SR sites of multiple BSSs to obtain N sta ; where N sta satisfies the following formula:
  • the BSS i represents the number of i-th active sites or the number of active SR sites
  • W i represents the number of i-th active sites or weighting coefficients of active SR sites
  • N BSS represents the number of active sites or the number of active SR sites.
  • the first station calculates an initial backoff duration CW1 according to N sta ;
  • Step 1410 The first station starts to send data if the channel is in an idle state after the backoff is completed.
  • Step 1411 The first station sets the NAV according to the duration of the duration in the PPDU, and delays the time of sending the data. The process ends.
  • the time for obtaining the first data is a preamble duration. Therefore, after detecting the PPDU, only one preamble duration plus one SRIFS or one PIFS may be used to perform backoff, and SRIFS and PIFS are performed.
  • the duration is less than DIFS, thus reducing the length of time to enter the backoff process, further reducing the waiting time before the station sends data, and improving the efficiency of space reuse.
  • the received signal strength of the PPDU may be indicated by the RSSI of the PPDU.
  • the embodiment of the present invention further provides a back-off device based on spatial reuse.
  • the method corresponding to the space-reuse-based back-off device is a space reuse-based backoff method according to the embodiment of the present invention.
  • the implementation of the method refer to the implementation of the method, and the repeated description will not be repeated.
  • the backoff device based on space reuse in the embodiment of the present invention includes:
  • the transceiver module 1500 is configured to detect, in the channel monitoring process, a physical layer protocol data unit PPDU transmission in the channel;
  • the processing module 1501 is configured to: after determining that the received signal strength of the detected PPDU is not less than the first monitoring threshold, suspending the channel monitoring process, and demodulating the PPDU to obtain the first data; the first monitoring threshold is that the device is in the channel monitoring process.
  • the adopted PPDU monitoring threshold; the first data includes the cell indication information carried by the signaling field of the PPDU and/or the address information in the medium access control MAC field;
  • the processing module 1501 is further configured to: if the PPDU is the overlapping basic service set OBSS PPDU according to the first data, in the first time interval after the first data is obtained, use the second monitoring threshold as the device in the subsequent channel monitoring.
  • the PPDU monitoring threshold in the process the second monitoring threshold is greater than the first monitoring threshold, and the first time interval is less than a distributed interframe space DIFS; and in the first time Treatment after the interval;
  • the transceiver module 1500 is further configured to start sending data if the channel is in an idle state after the backoff is completed.
  • the first time interval includes at least one transmitting the first data from the physical layer. a delay D1 to the MAC layer and a delay M1 at which the at least one MAC layer processes the first data and at least one duration CCAdel required to perform the channel assessment CCA detection;
  • the processing module 1501 is configured to:
  • the backoff is performed after the first time interval.
  • processing module 1501 is configured to:
  • N sta represents the weighted average of the number of active SR sites or the number of active sites.
  • the active SR site is a site that is OBSS with the device, and the active site is a site where the device can frame the PPDU.
  • the first time interval includes at least one D1 and at least one M1.
  • processing module 1501 is configured to:
  • processing module 1501 is configured to:
  • Determining the remaining backoff duration according to the pause time of the channel monitoring process Determining the remaining backoff duration according to the pause time of the channel monitoring process; adjusting the remaining backoff duration according to the received signal strength of the PPDU to obtain a new backoff duration; and performing backoff according to the new backoff duration;
  • New_BO Remaining_BO* ⁇
  • New_BO is the new backoff duration
  • Remaining_BO is the remaining backoff duration, where 0 ⁇ 1, and ⁇ is proportional to the received signal strength of the PPDU.
  • the SRIFS includes a D1, an M1, and a duration CCAdel required for performing a channel assessment CCA detection;
  • the processing module 1501 is configured to include:
  • the processing module 1501 is configured to:
  • the channel is determined to be in an idle state in the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the first time interval is a PIFS
  • the processing module 1501 is configured to:
  • the processing module 1501 is configured to:
  • the channel is determined to be in an idle state in the CCAdel, wherein the channel is in an idle state when the received signal strength of the PPDU is less than the second monitoring threshold.
  • the second monitoring threshold is an OBSS PPDU monitoring threshold.
  • the transceiver module 1500 can be implemented by a transceiver
  • the processing module 1501 can be implemented by a processor.
  • the space reuse-based backoff device 1600 can A processor 1610, a transceiver 1620, and a memory 1630 are included.
  • the memory 1630 may be used to retract the program/code pre-installed when the device 1600 is shipped from the factory, or may store code or the like for execution of the processor 1610.
  • a bus system 1640 that includes, in addition to the data bus, a power bus, a control bus, and a status signal bus.
  • the processor 1610 can be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for performing related operations.
  • CPU central processing unit
  • ASIC application specific integrated circuit
  • space reuse-based backoff device 1600 shown in FIG. 16 only shows the processor 1610, the transceiver 1620, and the memory 1630, in a specific implementation process, those skilled in the art will appreciate that the device also includes Other devices necessary for proper operation. At the same time, those skilled in the art will appreciate that the device may also include hardware devices that implement other additional functions, depending on the particular needs. Moreover, those skilled in the art will appreciate that the device may also only include the devices or modules necessary to implement the embodiments of the present invention, and do not necessarily include all of the devices shown in FIG.
  • the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).
  • the first station detects the physical layer protocol data unit PPDU transmission in the channel during the channel monitoring process; after determining that the received signal strength of the detected PPDU is not less than the first monitoring threshold, the channel is suspended.
  • Monitoring the process and demodulating the PPDU to obtain the first data is a PPDU monitoring threshold used by the first station in the channel monitoring process; the first data includes cell indication information and/or media access carried by the signaling field of the PPDU.
  • the second monitoring threshold is used as the PPDU monitoring threshold of the first station in the subsequent channel monitoring process, and the second monitoring threshold is greater than the first monitoring threshold, and the first time interval is smaller than A distributed interframe space DIFS; backoff is performed after the first time interval; if the channel is in an idle state after the backoff is completed, data transmission is started.
  • This technical solution reduces the time before the backoff because the OBSS PPDU in the channel is detected during the channel monitoring process, and the backoff is performed after the first time interval, and the first time interval is less than a distributed interframe space DIFS. The interval, so that the station can enter the backoff process faster, and the PPDU monitoring threshold in the subsequent channel monitoring process is improved, further reducing the waiting time before the station sends data, thereby greatly improving the efficiency of space reuse.
  • embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • the computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device.
  • the apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.
  • These computer program instructions can also be loaded onto a computer or other programmable data processing device. Having a series of operational steps performed on a computer or other programmable device to produce computer-implemented processing such that instructions executed on a computer or other programmable device are provided for implementing one or more processes and/or block diagrams in the flowchart. The steps of a function specified in a box or multiple boxes.

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Abstract

本发明公开了一种基于空间重用的退避方法及设备，涉及无线通信技术领域，用以解决目前空间重用效率较低问题。该方法包括：第一站点确定侦听到的PPDU为OBSS PPDU时，则将第二监测门限作为第一站点在后续的信道监测过程中的PPDU监测门限，第二监测门限值大于第一监测门限值，第一时间间隔小于一个DIFS；在第一时间间隔之后进行退避；当退避完成后若信道处于空闲状态，则开始发送数据。这种技术方案由于在信道监测过程中侦听到信道中有OBSS PPDU后，在第一时间间隔之后进行退避，由于第一时间间隔小于一个分布式帧间间隔DIFS，并且提高了后续信道监测过程中的PPDU监测门限，从而大大提高了空间重用的效率。

Description

一种基于空间重用的退避方法及设备
本申请要求在2015年12月31日提交中国专利局、申请号为201511032052.8、申请名称为“一种基于空间重用的退避方法及设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及无线通信技术领域，特别涉及一种基于空间重用的退避方法及设备。
背景技术
在WLAN(Wireless Local Area Networks，无线局域网络)系统中，如图1所示，STA1关联于AP(Wireless Access Point，无线接入点)1，STA2、STA3关联于AP2，STA1与STA2为互为OBSS(overlapping Basic Service Set，交叠基本服务集)的站点，当STA1与AP1之间有PPDU(PLCP Protocol data Unit，物理层协议数据单元)传输时，在范围100处的接收信号强度为-72dBm，在范围101处的接收信号强度为-82dBm，假设STA2与STA3的PPDU监测门限为-82dBm，当STA2在退避过程中侦听到PPDU时，其退避机制如图2a所示，由于接收信号强度大于PPDU监测门限，STA2中止该退避过程，等待OBSS PPDU传输结束后，再经过一个DIFS(Distributed Inter-frame Spacing，分布式帧间间隔)时长，且信道保持空闲状态后，STA2继续未完成的退避过程；或者当STA2在处于DIFS的信道监测过程中侦听到PPDU时，其退避机制如图2b所示，STA2中止DIFS对应的信道监测过程，等待OBSS PPDU传输结束后，再经过一个DIFS的时长，且信道保持空闲状态后，STA2根据竞争窗口随机选择一个退避时长，执行新的退避过程。
为提升吞吐量和空间重用效率，IEEE 802.11工作组于2013年成立高效无线局域网研究组(High Efficiency WLAN Study Group,HEW SG)，2014年成 立802.11ax工作组(TGax)，802.11ax协议提出了在密集环境中采用空间复用的特性来提高网络的吞吐量和空间重用的效率，具体的，当STA2在退避过程中的信道监测过程中侦听到PPDU时，其退避机制如图3所示，STA2确定该PPDU为OBSS PPDU，经过一个DIFS的时长后，进行退避，竞争信道，即STA2在侦听到PPDU后，需要至少经过一个PPDU的preamble时长加一个DIFS时长进行退避，竞争信道。
而对于如图1所示的STA3在退避过程中侦听到PPDU后，该PPDU的接收信号强度小于PPDU监测门限，因此，STA3继续进行退避，若STA3在退避过程中信道一直处于空闲，即可发送数据。
虽然相对于图2a与图2b的退避机制，图3的退避机制一定程度上提高了空间重用的效率，但是相对于STA3来说，进行退避前所花费时间还是较长，空间重用效率较低。
发明内容
本发明提供一种基于空间重用的退避方法及设备，用以解决现有技术中存在空间重用效率较低问题。
第一方面，提供了一种基于空间重用的退避方法，包括：
第一站点在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
所述第一站点在确定所述侦听到的PPDU的接收信号强度不小于第一监测门限后，中止所述信道监测过程，并解调所述PPDU得到第一数据；所述第一监测门限为所述第一站点在所述信道监测过程中采用的PPDU监测门限；所述第一数据包括所述PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
所述第一站点在得到所述第一数据之后的第一时间间隔内，若根据所述第一数据，确定所述PPDU为交叠基础服务集OBSS PPDU，则将第二监测门 限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，所述第二监测门限值大于所述第一监测门限值，所述第一时间间隔小于一个分布式帧间间隔DIFS；
所述第一站点在所述第一时间间隔之后进行退避；
所述第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
结合第一方面，在第一方面的第一种可能的实现方式中，若所述信道监测过程为点帧间间隔PIFS或DIFS或扩展帧间间隔EIFS或仲裁帧间间隔AIFS中的信道监测过程，则所述第一时间间隔包括至少一个将所述第一数据从物理层传输到MAC层的延迟D1和至少一个所述MAC层处理所述第一数据的延迟M1和至少一个进行一次信道评估CCA检测所需要的时长CCAdel；
所述第一站点在所述第一时间间隔之后进行退避，包括：
所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态后，在所述第一时间间隔之后进行退避。
结合第一方面的第一种可能的实现方式，在第一方面的第二种可能的实现方式中，所述第一站点进行退避，包括：
所述第一站点根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2，CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于所述PPDU的接收信号强度；
或者
所述第一站点根据当前的竞争窗口随机选择的退避时长，进行退避；或者
所述第一站点根据活跃站点的数量或空间重用SR活跃站点的数量，确定退避过程所使用退避时长CW1；所述CW1满足下列公式：
Figure PCTCN2016106983-appb-000001
其中，Nsta表示所述活跃SR站点的数量或所述活跃站点的数量的加权平均值，所述活跃SR站点为与所述第一站点互为OBSS的站点，所述活跃站 点为所述第一站点能够帧听到PPDU的站点。
结合第一方面，在第一方面的第三种可能的实现方式中，若所述信道信测过程为退避过程中的信道监测过程，则所述第一时间间隔包括至少一个D1和至少一个M1。
结合第一方面的第三种可能的实现方式，在第一方面的第四种可能的实现方式中，所述第一站点进行退避，包括：
所述第一站点根据所述信道监测过程的中止时刻，确定剩余的退避时长，并将所述CW1设置为所述剩余的退避时长；
所述第一站点根据所述剩余的退避时长，进行退避。
结合第一方面的第三种可能的实现方式，在第一方面的第五种可能的实现方式中，所述第一站点进行退避，包括：
所述第一站点根据所述信道监测过程的中止时刻，确定剩余的退避时长；
所述第一站点根据所述PPDU的接收信号强度调整所述剩余的退避时长，得到新的退避时长；
所述第一站点根据新的退避时长，进行退避；
所述退避时长与所述剩余的退避时长满足下列公式：
New_BO＝Remaining_BO*α；
其中，New_BO为所述新的退避时长，Remaining_BO为所述剩余的退避时长，其中0＜α＜1，且α正比于所述PPDU的接收信号强度。
结合第一方面至第一方面的第五种可能的实现方式，在第一方面的第六种可能的实现方式中，若所述第一时间间隔为一个空间重用帧间隔SRIFS，所述SRIFS包括一个D1、一个M1和一个进行一次信道评估CCA检测所需要的时长CCAdel；
所述第一站点在所述第一时间间隔内确定所述PPDU为所述OBSS PPDU，则将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，包括：
所述第一站点在所述第一时间间隔的D1和M1内确定所述PPDU为所述 OBSS PPDU，则将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限；
所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态，包括：
所述第一站点在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
结合第一方面至第一方面的第五种可能的实现方式，在第一方面的第七种可能的实现方式中，若所述第一时间间隔为一个PIFS；
所述第一站点在所述第一时间间隔内确定所述PPDU为所述OBSS PPDU，将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，包括：
所述第一站点在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，并将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限；
所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态，包括：
所述第一站点在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
结合第一方面至第一方面的第七种可能的实现方式，在第一方面的第八种可能的实现方式中，所述第二监测门限为OBSS PPDU监测门限。
第二方面，一种基于空间重用的退避设备，其特征在于，包括：
收发模块，用于在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
处理模块，用于在确定所述侦听到的PPDU的接收信号强度不小于第一监测门限后，中止所述信道监测过程，并解调所述PPDU得到第一数据；所述第一监测门限为所述设备在所述信道监测过程中采用的PPDU监测门限；所述第一数据包括所述PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
所述处理模块还用于，在得到所述第一数据之后的第一时间间隔内，若 根据所述第一数据，确定所述PPDU为交叠基础服务集OBSS PPDU，则将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限，所述第二监测门限值大于所述第一监测门限值，所述第一时间间隔小于一个分布式帧间间隔DIFS；并在所述第一时间间隔之后进行退避；
所述收发模块还用于，当退避完成后若信道处于空闲状态，则开始发送数据。
结合第二方面，在第二方面的第一种可能的实现方式中，若所述信道监测过程为点帧间间隔PIFS或DIFS或扩展帧间间隔EIFS或仲裁帧间间隔AIFS中的信道监测过程，则所述第一时间间隔包括至少一个将所述第一数据从物理层传输到MAC层的延迟D1和至少一个所述MAC层处理所述第一数据的延迟M1和至少一个进行一次信道评估CCA检测所需要的时长CCAdel；
所述处理模块，用于：
在所述第一时间间隔内确定所述信道处于空闲状态后，在所述第一时间间隔之后进行退避。
结合第二方面的第一种可能的实现方式，在第二方面的第二种可能的实现方式中，所述处理模块，用于：
根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2，CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于所述PPDU的接收信号强度；
或者
根据当前的竞争窗口随机选择的退避时长，进行退避；或者
根据活跃站点的数量或空间重用SR活跃站点的数量，确定退避过程所使用退避时长CW1；所述CW1满足下列公式：
Figure PCTCN2016106983-appb-000002
其中，Nsta表示所述活跃SR站点的数量或所述活跃站点的数量的加权平均值，所述活跃SR站点为与所述设备互为OBSS的站点，所述活跃站点为 所述设备能够帧听到PPDU的站点。
结合第二方面，在第二方面的第三种可能的实现方式中，若所述信道信测过程为退避过程中的信道监测过程，则所述第一时间间隔包括至少一个D1和至少一个M1。
结合第二方面的第三种可能的实现方式，在第二方面的第四种可能的实现方式中，所述处理模块，用于：
根据所述信道监测过程的中止时刻，确定剩余的退避时长，并将所述CW1设置为所述剩余的退避时长；并根据所述剩余的退避时长，进行退避。
结合第二方面的第三种可能的实现方式，在第二方面的第五种可能的实现方式中，所述处理模块，用于：
根据所述信道监测过程的中止时刻，确定剩余的退避时长；根据所述PPDU的接收信号强度调整所述剩余的退避时长，得到新的退避时长；并根据新的退避时长，进行退避；
所述退避时长与所述剩余的退避时长满足下列公式：
New_BO＝Remaining_BO*α；
其中，New_BO为所述新的退避时长，Remaining_BO为所述剩余的退避时长，其中0＜α＜1，且α正比于所述PPDU的接收信号强度。
结合第二方面至第二方面的第四种可能的实现方式，在第二方面的第五种可能的实现方式中，若所述第一时间间隔为一个空间重用帧间隔SRIFS，所述SRIFS包括一个D1、一个M1和一个进行一次信道评估CCA检测所需要的时长CCAdel；
所述处理模块，用于包括：
在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，则将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限；
所述处理模块，用于：
在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
结合第二方面至第二方面的第四种可能的实现方式，在第二方面的第六种可能的实现方式中，若所述第一时间间隔为一个PIFS；
所述处理模块，用于：
在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，并将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限；
所述处理模块，用于：
在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
结合第二方面至第二方面的第六种可能的实现方式，在第二方面的第七种可能的实现方式中，所述第二监测门限为OBSS PPDU监测门限。
在本发明技术方案中，由于在信道监测过程中侦听到信道中有OBSSPPDU后，在第一时间间隔之后进行退避，并且第一时间间隔小于一个分布式帧间间隔DIFS，因此减少了退避之前的时间间隔，从而使得站点能够较快的进入退避过程，并且由于提高了后续信道监测过程中的PPDU监测门限，进一步减少了站点发送数据前的等待时间，从而大大提高了空间重用的效率。
附图说明
图1为WLAN系统中站点竞争信道场景图；
图2a为现有技术中退避机制示意图；
图2b为现有技术中退避机制示意图；
图3为现有技术中退避机制示意图；
图4为本发明实施例应用场景示意图；
图5为DIFS结构示意图；
图6为本发明实施例基于空间重用的退避方法流程示意图；
图7为本发明实施例退避机制示意图；
图8为本发明实施例基于空间重用的退避方法流程示意图；
图9为802.11ax中PPDU帧结构示意图；
图10为本发明实施例中SRIFS结构示意图；
图11为本发明实施例退避机制示意图；
图12为本发明实施例基于空间重用的退避方法流程示意图；
图13为本发明实施例退避机制示意图；
图14为本发明实施例基于空间重用的退避方法流程示意图；
图15为本发明实施例基于空间重用的退避设备示意图；
图16为本发明实施例基于空间重用的退避设备硬件结构示意图。
具体实施方式
为了使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请作进一步地详细描述，显然，所描述的实施例仅仅是本申请的一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本申请保护的范围。
如图4所示，本发明实施例的应用场景示意图，第一站点关联于AP1，第二站点关联于AP2，第一站点与第二站点为互为OBSS的站点，其中，第一站点与AP1之间正在进行PPDU的传输，其在范围400的接收信号强度为-72dBm，第一站点的第一监测门限为-82dBm，若第一站点信道监测过程中侦听到PPDU后的基于空间重用的退避方法，下面结合附图对本申请进行详细说明。
特别地，当第一时间间隔为SRIFS(Spatial Reuse Inter-Frame Space，空间重用帧间间隔)时，不但可以应用于在退避过程中的信道监测过程中侦听到信道中有PPDU传输时，第一站点的退避机制，还可以应用于DIFS或PIFS(Piont Inter-Frame Space，点帧间间隔)或EIFS(Extended Inter-frame Space，扩展帧间间隔)或AIFS(Arbitration Inter-Frame Space，仲裁帧间间隔)内信 道监测过程中侦听到信道中有PPDU传输时，第一站点的退避机制，第一时间间隔为PIFS时与SRIFS类似，在此不再赘述。
其中，PIFS如图5所示，包括一个SIFS(Short Inter-Frame Space，短帧帧间间隔)和一个Slot Time，其中，SIFS包括一个D1、一个M1和一个Rx/Tx，一个Slot Time包括一个D2、一个CCAdel，一个M2、一个Rx/Tx，DIFS如图5所示，包括一个PIFS和一个Slot Time。
EIFS包括一个SIFS、一个ACKTxTime和一个DIFS；AIFS包括一个SIFS和AIFSSN个Slot Time。
其中，D1为将第一数据从物理层传输到MAC层的延迟；
M1为MAC层处理第一数据的延迟；
CCAdel为进行一次CCA(Clear Channel Assessment，信道评估)检测所需要的时长；
Rx/Tx为射频电路接收/发射转化时间；
D2为D1和WiFi信号的最大传输时延；
M2与M1相同，为MAC层处理第一数据的延迟。
ACKTxTime为在最低要求速率下传输控制帧ACK的时间长度；
AIFSSN为信道接入的类别对应的数值。
下面结合附图对本发明实施例进行详细说明。
如图6所示，本发明实施例基于空间重用的退避方法，包括：
步骤600，第一站点在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
步骤601，第一站点在确定侦听到的PPDU的接收信号强度不小于第一监测门限后，中止信道监测过程，并解调PPDU得到第一数据；第一监测门限为第一站点在信道监测过程中采用的PPDU监测门限；第一数据包括PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
步骤602，第一站点在得到第一数据之后的第一时间间隔内，若根据第一数据，确定PPDU为交叠基础服务集OBSS PPDU，则将第二监测门限作为第 一站点在后续的信道监测过程中的PPDU监测门限，第二监测门限值大于第一监测门限值，第一时间间隔小于一个分布式帧间间隔DIFS；
步骤603，第一站点在第一时间间隔之后进行退避；
步骤604，第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
下面根据不同的应用场景进行具体介绍。
实施例一
第一站点在退避过程中的信道监测过程中侦听到信道中有PPDU传输，其中，如图8所示，按照图7所示的退避机制，基于空间重用的退避方法，包括：
步骤800，第一站点在退避过程中的信道监测过程中侦听到信道中有PPDU传输；
步骤801，第一站点判断侦听到的该PPDU的接收信号强度是否不小于第一站点的第一监测门限，若是，执行步骤802，否则执行步骤803；
其中，第一监测门限为第一站点在该信道监测过程中采用的PPDU监测门限，可选的，第一监测门限为传统PPDU监测门限。
步骤802，第一站点中止退避过程中的信道监测过程，执行步骤804；
步骤803，第一站点继续退避过程中的信道监测过程，本流程结束；
步骤804，第一站点对该PPDU解调，得到第一数据；
需要说明的是，在802.11ax协议中，携带小区指示信息的信令字段为HE-SIG-A(High Efficiency Signal Frame A，高效率信令帧A)，具体的，802.11ax协议中的PPDU帧结构格式如图9所示，第一站点对该PPDU在解调到PPDU中的HE-SIG-A时，得到第一数据，该第一数据包括HE-SIG-A上承载的小区指示信息，其中，HE-SIG-A上承载的小区指示信息为BSS标识信息，具体的，BSS标识信息为BSS color值；或者
第一站点对该PPDU在解调到PPDU中的MAC Header时，得到第一数据，该第一数据包括MAC字段中的地址信息，具体的MAC字段的地址信息中包括该第一站点所在的小区的BSSID。
其中，图9中英文缩写对应的中文全称以及英文全称如表1所示。
表1
Figure PCTCN2016106983-appb-000003
步骤805，第一站点根据第一数据，判断该PPDU是否为OBSS PPDU，若是，执行步骤806，否则执行步骤807；
其中，具体的，当第一数据为HE-SIG-A上承载的BSS color值时，若该BSS color值与第一站点所在小区的BSS color值相等，则该PPDU不是OBSS PPDU，若该BSS color值与第一站点所在小区的BSS color值不相等，则该PPDU为OBSS PPDU；
当第一数据为MAC Header中的地址信息时，若地址信息中的BSSID(Basic Service Set Identification，基本服务集标识)与第一站点所在小区对应的BBSID相同，则该PPDU不为OBSS PPDU，若地址信息中的BSSID与第一站点所在小区对应的BSSID不同，则该PPDU为OBSS PPDU。
步骤806，第一站点在得到第一数据之后的第一时间间隔，将第二监测门限作为该第一站点在后续的信道监测过程中的监测门限，其中，第二监测门限大于所述第一监测门限，执行步骤808。
需要说明的是，若第一时间间隔为SRIFS，其中SRIFS如图10所示，包 括一个第一数据从物理层传输到MAC层的延迟D1、一个MAC层处理所述第一数据的延迟M1和一个进行一次信道空闲检测所需要的时长CCAdel；若第一时间间隔为PIFS，如图5所示，包括一个SIFS和一个Slot Time，其中一个SIFS包括一个D1、一个M1、一个Rx/Tx和一个Slot Time，其中一个Slot Time包括一个D2、一个CCAdel、一个M2和一个Rx/Tx，其中D2为D1和WiFi信号的最大传输时延，Rx/Tx为射频电路接收/发射转化时间；
具体的，第一站点在第一时间间隔的D1和M1内，将第二监测门限作为所述第一站点在后续的信道监测过程中的监测门限，第二监测门限大于所述第一监测门限，然后执行步骤808。
可选的，第二监测门限为OBSS PPDU监测门限。
需要说明的是，步骤805中，第一站点在第一时间间隔的D1和M1内，根据第一数据，判断该PPDU是否为OBSS PPDU。
步骤807，第一站点根据PPDU中的duration时长，更新NAV，数据发送延迟；
具体的，若duration时长大于当前NAV设置的值，则将NAV设置为duration时长，若duration时长不大于当前NAV设置的值，则保持NAV的设置。
步骤808，第一站点判断PPDU的接收信号强度是否小于第二监测门限值，若是，则执行步骤809，否则执行步骤811。
步骤809，第一站点确定信道处于空闲状态，则在第一时间间隔之后进行退避。
需要说明的是，在得到第一数据之后的第一时间间隔之后进行退避包括两种退避方案，一种是：第一站点根据信道监测过程的中止时刻，确定剩余的退避时长；根据剩余的退避时长，进行退避；
另一种是：第一站点根据信道监测过程的中止时刻，确定剩余的退避时长；根据PPDU的接收信号强度调整剩余的退避时长，得到新的退避时长，并根据新的退避时长，进行退避；
其中，退避时长满足下列公式：
New_BO＝Remaining_BO*α；
其中，New_BO为新的退避时长，Remaining_BO为剩余的退避时长，其中0＜α＜1，且α正比于PPDU的接收信号强度。
由于重新计算的退避时长与剩余的退避时长相比，退避时长缩短了，因此进一步减少了第一站点发送数据前的等待时间，提高了空间重用的效率。
步骤810，第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
步骤811，第一站点根据PPDU中的duration时长更新NAV，延迟发送数据的时间，本流程结束。
其中，对该PPDU解调，得到第一数据的时长为一个preamble时长，因此，在侦听到PPDU后，仅需要经过一个preamble时长加一个SRIFS或一个PIFS,就能进行退避，而SRIFS、PIFS的时长小于DIFS，因此减少了进入退避过程的时长，进一步减少了站点发送数据前的等待时间，从而使得站点能够较快的进入退避过程，并且由于提高了后续信道监测过程中的PPDU监测门限，进一步减少了站点发送数据前的等待时间，从而大大提高了空间重用的效率。
实施例二
第一站点在退避过程中的信道监测过程中侦听到信道中有PPDU传输，其中，如图12所示，按照图11所示的退避机制，基于空间重用的退避方法，包括：
步骤1200，第一站点在退避过程中的信道监测过程中侦听到信道中有PPDU传输；
步骤1201，第一站点判断侦听到的PPDU的接收信号强度是否不小于第一站点的第一监测门限，若是，执行步骤1202，否则执行步骤1203；
可选的，第一监测门限为第一站点在该信道监测过程中采用的PPDU监测门限，可选的，第一监测门限为传统PPDU监测门限。
步骤1202，第一站点中止退避过程中的信道监测过程，执行步骤1204；
步骤1203，第一站点继续退避过程中的信道监测过程，本流程结束；
步骤1204，第一站点对该PPDU解调，得到第一数据；
需要说明的是，在802.11ax协议中，携带小区指示信息的信令字段为HE-SIG-A，具体的，802.11ax协议中的PPDU帧结构格式如图8所示，第一站点对该PPDU在解调到PPDU中的HE-SIG-A时，得到第一数据，该第一数据包括HE-SIG-A上承载的小区指示信息，其中，HE-SIG-A上承载的小区指示信息为BSS标识信息，具体的，BSS标识信息为BSS color值；或者
第一站点对该PPDU在解调到PPDU中的MAC Header时，得到第一数据，该第一数据包括MAC字段中的地址信息，具体的MAC字段的地址信息为该第一站点所在的小区的BSSID。
步骤1205，第一站点根据第一数据，判断该PPDU是否为OBSS PPDU，若是，执行步骤1206，否则执行步骤1209；
其中，具体的，当第一数据为HE-SIG-A上承载的BSS color值时，若该BSS color值与第一站点所在小区的BSS color值相等，则该PPDU不是OBSS PPDU，若该BSS color值与第一站点所在小区的BSS color值不相等，则该PPDU为OBSS PPDU；
当第一数据为MAC Header中的地址信息时，若地址信息中的BSSID与第一站点所在小区对应的BSSID相同，则该PPDU不为OBSS PPDU，若地址信息中的BSSID与第一站点所在小区对应的BSSID不同，则该PPDU为OBSS PPDU。
步骤1206，第一站点在得到第一数据之后的第一时间间隔，将第二监测门限作为该第一站点在后续的信道监测过程中的监测门限，其中，第二监测门限大于第一监测门限。
其中，第一时间间隔包括第一数据从物理层传输到MAC层的延迟M1和第一数据从物理层传输到MAC层的延迟D1。
步骤1206中，第一站点在第一时间间隔D1和M1内，将第二监测门限作为该第一站点在后续的信道监测过程中的监测门限。
需要说明的是，步骤1205中，第一站点在第一时间间隔D1和M1内，根据第一数据，判断该PPDU是否为OBSS PPDU。
步骤1207，第一站点采用第二监测门限，在得到所述第一数据之后的第一时间间隔之后，进行退避。
步骤1208，第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
可选的，第二监测门限值为OBSS PPDU监测门限值。
需要说明的是，在得到第一数据之后的第一时间间隔之后进行退避包括两种退避方案，一种是：第一站点根据信道监测过程的中止时刻，确定剩余的退避时长；根据剩余的退避时长，进行退避；
另一种是：第一站点根据信道监测过程的中止时刻，确定剩余的退避时长；根据PPDU的接收信号强度调整剩余的退避时长，得到新的退避时长，并根据新的退避时长，进行退避；
其中，退避时长满足下列公式：
New_BO＝Remaining_BO*α；
其中，New_BO为新的退避时长，Remaining_BO为剩余的退避时长，其中0＜α＜1，且α正比于PPDU的接收信号强度。
由于重新计算的退避时长与剩余的退避时长相比，退避时长缩短了，因此进一步减少了第一站点发送数据前的等待时间，提高了空间重用的效率。
步骤1209，第一站点根据PPDU中的duration时长，更新NAV，数据发送延迟
具体的，若duration时长大于当前NAV设置的值，则将NAV设置为duration时长，若duration时长不大于当前NAV设置的值，则保持NAV的设置。
其中，对该PPDU解调，得到第一数据的时间为一个preamble时长，因此，在侦听到PPDU后，仅需要经过一个preamble时长加一个D1和M1的时长，而D1和M1的时长小于DIFS，因此减少了进入退避过程的时长，进一 步减少了站点发送数据前的等待时间，从而使得站点能够较快的进入退避过程，并且由于提高了后续信道监测过程中的PPDU监测门限，进一步减少了站点发送数据前的等待时间，从而大大提高了空间重用的效率。
实施例三
第一站点在信道监测过程中侦听到信道中有PPDU传输，其中，信道监测的过程为PIFS或DIFS或EIFS或AIFS中的信道监测过程，如图14所示，按照图13所示的退避机制，基于空间重用的退避方法，包括：
步骤1400，第一站点在信道监测过程中侦听到信道中有PPDU传输；
步骤1401，第一站点判断该PPDU的接收信号强度是否不小于第一站点的第一监测门限，若是，执行步骤1402，否则执行步骤1403；
其中，第一监测门限为第一站点在该信道监测过程中采用的PPDU监测门限，可选的，第一监测门限为传统PPDU监测门限。
步骤1402，第一站点中止信道监测过程，执行步骤1404；
步骤1403，第一站点继续信道监测过程，本流程结束；
步骤1404，第一站点对该PPDU解调，得到第一数据；
需要说明的是，在802.11ax协议中，携带小区指示信息的信令字段为HE-SIG-A，具体的，802.11ax协议中的PPDU帧结构格式如图9所示，第一站点对该PPDU在解调到PPDU中的HE-SIG-A时，得到第一数据，该第一数据包括HE-SIG-A上承载的小区指示信息，其中，HE-SIG-A上承载的小区指示信息为BSS标识信息，具体的，BSS标识信息为BSS color值；或者
第一站点对该PPDU在解调到PPDU中的MAC Header时，得到第一数据，该第一数据包括MAC字段中的地址信息，具体的MAC字段的地址信息中包括该第一站点所在的小区的BSSID。
步骤1405，第一站点根据第一数据，判断该PPDU是否为OBSS PPDU，若是，执行步骤1406，否则执行步骤1407；
其中，具体的，当第一数据为HE-SIG-A上承载的BSS color值时，若该BSS color值与第一站点所在小区的BSS color值相等，则该PPDU不是OBSS  PPDU，若该BSS color值与第一站点所在小区的BSS color值不相等，则该PPDU为OBSS PPDU；
当第一数据为MAC Header中的地址信息时，若地址信息中的BSS ID(Basic Service Set Identification，基本服务集标识)与第一站点所在小区对应的BBSID相同，则该PPDU不为OBSS PPDU，若地址信息中的BSSID与第一站点所在小区对应的BSSID不同，则该PPDU为OBSS PPDU。
步骤1406，第一站点在得到所述第一数据之后的第一时间间隔，将第二监测门限作为该第一站点在后续的信道监测过程中的监测门限，其中，第二监测门限大于第一监测门限；
需要说明的是，若第一时间间隔为SRIFS，其中SRIFS如图10所示，包括第一数据从物理层传输到MAC层的延迟D1、至少一个MAC层处理所述第一数据的延迟M1和进行一次信道评估CCA检测所需要的时长CCAdel；若第一时间间隔为PIFS，如图5所示，包括一个SIFS和一个Slot Time，其中一个SIFS包括一个D1、一个M1、一个Rx/Tx和一个Slot Time，其中一个Slot Time包括一个D2、一个CCAdel、一个M2和一个Rx/Tx，其中D2为D1和WiFi信号的最大传输时延，Rx/Tx为射频电路接收/发射转化时间。
具体的，第一站点在第一时间间隔的D1和M1内，将第二监测门限作为所述第一站点在后续的信道监测过程中的监测门限，第二监测门限大于所述第一监测门限，然后执行步骤1408。
可选的，第二监测门限为OBSS PPDU监测门限。
需要说明的是，步骤1405中，第一站点在第一时间间隔的D1和M1内，根据第一数据，判断该PPDU是否为OBSS PPDU。
步骤1407，根据PPDU中的duration时长，更新NAV，数据发送延迟。
具体的，若duration时长大于当前NAV设置的值，则将NAV设置为duration时长，若duration时长不大于当前NAV设置的值，则保持NAV的设置。
步骤1408，第一站点判断该PPDU的接收信号强度是否小于第二监测门 限，若是，则执行步骤1409，否则执行步骤1411。
步骤1409，第一站点确定信道处于空闲状态，则在得到第一数据之后的第一时间间隔之后进行退避。
需要说明的是，在得到第一数据之后的第一时间间隔之后进行退避包括三种方案：
第一种：第一站点根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2，CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于该PPDU的接收信号强度；
由于重新计算的退避时长与随机选择的退避时长相比，退避时长缩短了，因此进一步减少了第一站点发送数据前的等待时间，提高了空间重用的效率。
第二种：第一站点根据当前的竞争窗口随机选择的退避时长，进行退避；具体的，第一站点从当前的竞争窗口为{0,CWmin}的集合中随机选择一个退避时长CW1，进行退避；
第三种：第一站点根据活跃站点的数量或活跃空间重用SR站点的数量，确定退避过程所使用的退避时长CW1，根据退避时长CW1，进行退避；
CW1满足下列公式：
Figure PCTCN2016106983-appb-000004
其中，Nsta表示活跃SR站点的数量或活跃站点的数量的加权平均值，活跃SR站点为与第一站点互为OBSS的站点，且第一站点能够帧听到该站点的PPDU，活跃站点为第一站点能够帧听到PPDU的站点。
具体的，第一站点接收多个BSS的广播来收集多个BSS的活跃站点数量或活跃SR站点数量；其中，本BSS的活跃站点数量或活跃SR站点数量是AP通过Beacon或其他管理帧来广播给第一站的；
第一站点对多个BSS的活跃站点数量或活跃SR站点数量进行加权平均得到Nsta；其中Nsta满足下列公式：
Figure PCTCN2016106983-appb-000005
其中，BSSi表示第i个活跃站点数量或活跃SR站点数量，Wi表示第i个活跃站点数量或活跃SR站点的加权系数，NBSS表示活跃站点数量或活跃SR站点数量。
第一站点根据Nsta计算初始退避时长CW1；
Figure PCTCN2016106983-appb-000006
步骤1410，第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
步骤1411，第一站点根据PPDU中的duration时长设置NAV，延迟发送数据的时间，本流程结束。
其中，对该PPDU解调，得到第一数据的时间为一个preamble时长，因此，在侦听到PPDU后，仅需要经过一个preamble时长加一个SRIFS或一个PIFS,就能进行退避，而SRIFS、PIFS的时长小于DIFS，因此减少了进入退避过程的时长，进一步减少了站点发送数据前的等待时间，提高了空间重用的效率。
需要说明的是，在实施例一、实施例二、实施例三中，PPDU的接收信号强度可以通过PPDU的RSSI指示。
此外，对附图中涉及到未标注中文全称的英文缩写如表2所示。
表2
Figure PCTCN2016106983-appb-000007
Figure PCTCN2016106983-appb-000008
基于同一发明构思，本发明实施例中还提供了一种基于空间重用的退避设备，由于基于空间重用的退避设备对应的方法为本发明实施例基于空间重用的退避方法，因此本发明实施例设备的实施可以参见该方法的实施，重复之处不再赘述。
如图15所示，本发明实施例基于空间重用的退避设备，包括：
收发模块1500，用于在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
处理模块1501，用于在确定侦听到的PPDU的接收信号强度不小于第一监测门限后，中止信道监测过程，并解调PPDU得到第一数据；第一监测门限为设备在信道监测过程中采用的PPDU监测门限；第一数据包括PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
处理模块1501还用于，在得到第一数据之后的第一时间间隔内，若根据第一数据，确定PPDU为交叠基础服务集OBSS PPDU，则将第二监测门限作为设备在后续的信道监测过程中的PPDU监测门限，第二监测门限值大于第一监测门限值，第一时间间隔小于一个分布式帧间间隔DIFS；并在第一时间 间隔之后进行退避；
收发模块1500还用于，当退避完成后若信道处于空闲状态，则开始发送数据。
可选的，若信道监测过程为点帧间间隔PIFS或DIFS或扩展帧间间隔EIFS或仲裁帧间间隔AIFS中的信道监测过程，则第一时间间隔包括至少一个将第一数据从物理层传输到MAC层的延迟D1和至少一个MAC层处理第一数据的延迟M1和至少一个进行一次信道评估CCA检测所需要的时长CCAdel；
处理模块1501，用于：
在第一时间间隔内确定信道处于空闲状态后，在第一时间间隔之后进行退避。
可选的，处理模块1501，用于：
根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2，CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于PPDU的接收信号强度；
或者
根据当前的竞争窗口随机选择的退避时长，进行退避；或者
根据活跃站点的数量或空间重用SR活跃站点的数量，确定退避过程所使用退避时长CW1；CW1满足下列公式：
Figure PCTCN2016106983-appb-000009
其中，Nsta表示活跃SR站点的数量或活跃站点的数量的加权平均值，活跃SR站点为与设备互为OBSS的站点，活跃站点为设备能够帧听到PPDU的站点。
可选的，若信道信测过程为退避过程中的信道监测过程，则第一时间间隔包括至少一个D1和至少一个M1。
可选的，处理模块1501，用于：
根据信道监测过程的中止时刻，确定剩余的退避时长，并将CW1设置为 剩余的退避时长；并根据剩余的退避时长，进行退避。
可选的，处理模块1501，用于：
根据信道监测过程的中止时刻，确定剩余的退避时长；根据PPDU的接收信号强度调整剩余的退避时长，得到新的退避时长；并根据新的退避时长，进行退避；
退避时长与剩余的退避时长满足下列公式：
New_BO＝Remaining_BO*α；
其中，New_BO为新的退避时长，Remaining_BO为剩余的退避时长，其中0＜α＜1，且α正比于PPDU的接收信号强度。
可选的，若第一时间间隔为一个空间重用帧间隔SRIFS，SRIFS包括一个D1、一个M1和一个进行一次信道评估CCA检测所需要的时长CCAdel；
处理模块1501，用于包括：
在第一时间间隔的D1和M1内确定PPDU为OBSS PPDU，则将第二监测门限作为设备在后续的信道监测过程中的PPDU监测门限；
处理模块1501，用于：
在CCAdel内确定信道处于空闲状态，其中，在PPDU的接收信号强度小于第二监测门限时，信道处于空闲状态。
可选的，若第一时间间隔为一个PIFS；
处理模块1501，用于：
在第一时间间隔的D1和M1内确定PPDU为OBSS PPDU，并将第二监测门限作为设备在后续的信道监测过程中的PPDU监测门限；
处理模块1501，用于：
在CCAdel内确定信道处于空闲状态，其中，在PPDU的接收信号强度小于第二监测门限时，信道处于空闲状态。
可选的，第二监测门限为OBSS PPDU监测门限。
应注意，本发明实施例中，收发模块1500可以由收发器实现，处理模块1501可以由处理器实现。如图16所示，基于空间重用的退避设备1600可以 包括处理器1610、收发器1620和存储器1630。其中，存储器1630可以用于退避设备1600出厂时预装的程序/代码，也可以存储用于处理器1610执行时的代码等。
基于空间重用的退避设备1600中的各个组件通过总线系统1640耦合在一起，其中总线系统1640除包括数据总线之外，还包括电源总线、控制总线和状态信号总线。
其中，处理器1610可以采用通用的中央处理器(Central Processing Unit，CPU)，微处理器，应用专用集成电路(Application Specific Integrated Circuit，ASIC)，或者一个或多个集成电路，用于执行相关操作，以实现本发明实施例所提供的技术方案。
应注意，尽管图16所示的基于空间重用的退避设备1600仅仅示出了处理器1610、收发器1620和存储器1630，但是在具体实现过程中，本领域的技术人员应当明白，该设备还包含实现正常运行所必须的其他器件。同时，根据具体需要，本领域的技术人员应当明白，该设备还可包含实现其他附加功能的硬件器件。此外，本领域的技术人员应当明白，该设备也可仅仅包含实现本发明实施例所必须的器件或模块，而不必包含图16中所示的全部器件。
本领域普通技术人员可以理解实现上述实施例方法中的全部或部分流程，是可以通过计算机程序来指令相关的硬件来完成，上述的程序可存储于一计算机可读取存储介质中，该程序在执行时，可包括如上述各方法的实施例的流程。其中，上述的存储介质可为磁盘、光盘、只读存储记忆体(ROM：Read-Only Memory)或随机存储记忆体(RAM：Random Access Memory)等。
从上述内容可以看出：第一站点在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；在确定侦听到的PPDU的接收信号强度不小于第一监测门限后，中止信道监测过程，并解调PPDU得到第一数据；第一监测门限为第一站点在信道监测过程中采用的PPDU监测门限；第一数据包括PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；在得到第一数据之后的第一时间间隔内，若根据第一数据，确定PPDU 为交叠基础服务集OBSS PPDU，则将第二监测门限作为第一站点在后续的信道监测过程中的PPDU监测门限，第二监测门限值大于第一监测门限值，第一时间间隔小于一个分布式帧间间隔DIFS；在第一时间间隔之后进行退避；当退避完成后若信道处于空闲状态，则开始发送数据。这种技术方案由于在信道监测过程中侦听到信道中有OBSS PPDU后，在第一时间间隔之后进行退避，并且第一时间间隔小于一个分布式帧间间隔DIFS，因此减少了退避之前的时间间隔，从而使得站点能够较快的进入退避过程，并且由于提高了后续信道监测过程中的PPDU监测门限，进一步减少了站点发送数据前的等待时间，从而大大提高了空间重用的效率。
本领域内的技术人员应明白，本发明的实施例可提供为方法、系统、或计算机程序产品。因此，本发明可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本发明可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本发明是参照根据本发明实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上， 使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
尽管已描述了本发明的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本发明范围的所有变更和修改。
显然，本领域的技术人员可以对本发明进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (18)

  1. 一种基于空间重用的退避方法，其特征在于，包括：
    第一站点在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
    所述第一站点在确定所述侦听到的PPDU的接收信号强度不小于第一监测门限后，中止所述信道监测过程，并解调所述PPDU得到第一数据；所述第一监测门限为所述第一站点在所述信道监测过程中采用的PPDU监测门限；所述第一数据包括所述PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
    所述第一站点在得到所述第一数据之后的第一时间间隔内，若根据所述第一数据，确定所述PPDU为交叠基础服务集OBSS PPDU，则将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，所述第二监测门限值大于所述第一监测门限值，所述第一时间间隔小于一个分布式帧间间隔DIFS；
    所述第一站点在所述第一时间间隔之后进行退避；
    所述第一站点当退避完成后若信道处于空闲状态，则开始发送数据。
  2. 如权利要求1所述的方法，其特征在于，若所述信道监测过程为点帧间间隔PIFS或DIFS或扩展帧间间隔EIFS或仲裁帧间间隔AIFS中的信道监测过程，则所述第一时间间隔包括至少一个将所述第一数据从物理层传输到MAC层的延迟D1和至少一个所述MAC层处理所述第一数据的延迟M1和至少一个进行一次信道评估CCA检测所需要的时长CCAdel；
    所述第一站点在所述第一时间间隔之后进行退避，包括：
    所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态后，在所述第一时间间隔之后进行退避。
  3. 如权利要求2所述的方法，其特征在于，所述第一站点进行退避，包括：
    所述第一站点根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2，CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于所述PPDU的接收信号强度；
    或者
    所述第一站点根据当前的竞争窗口随机选择的退避时长，进行退避；或者
    所述第一站点根据活跃站点的数量或空间重用SR活跃站点的数量，确定退避过程所使用退避时长CW1；所述CW1满足下列公式：
    Figure PCTCN2016106983-appb-100001
    其中，Nsta表示所述活跃SR站点的数量或所述活跃站点的数量的加权平均值，所述活跃SR站点为与所述第一站点互为OBSS的站点，所述活跃站点为所述第一站点能够帧听到PPDU的站点。
  4. 如权利要求1所述的方法，其特征在于，若所述信道信测过程为退避过程中的信道监测过程，则所述第一时间间隔包括至少一个D1和至少一个M1。
  5. 如权利要求4所述的方法，其特征在于，所述第一站点进行退避，包括：
    所述第一站点根据所述信道监测过程的中止时刻，确定剩余的退避时长，并将所述CW1设置为所述剩余的退避时长；
    所述第一站点根据所述剩余的退避时长，进行退避。
  6. 如权利要求4所述的方法，其特征在于，所述第一站点进行退避，包括：
    所述第一站点根据所述信道监测过程的中止时刻，确定剩余的退避时长；
    所述第一站点根据所述PPDU的接收信号强度调整所述剩余的退避时长，得到新的退避时长；
    所述第一站点根据新的退避时长，进行退避；
    所述退避时长与所述剩余的退避时长满足下列公式：
    New_BO＝Remaining_BO*α；
    其中，New_BO为所述新的退避时长，Remaining_BO为所述剩余的退避时长，其中0＜α＜1，且α正比于所述PPDU的接收信号强度。
  7. 如权利要求1至6任一所述的方法，其特征在于，若所述第一时间间隔为一个空间重用帧间隔SRIFS，所述SRIFS包括一个D1、一个M1和一个进行一次信道评估CCA检测所需要的时长CCAdel；
    所述第一站点在所述第一时间间隔内确定所述PPDU为所述OBSS PPDU，则将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，包括：
    所述第一站点在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，则将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限；
    所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态，包括：
    所述第一站点在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
  8. 如权利要求1至6任一所述的方法，其特征在于，若所述第一时间间隔为一个PIFS；
    所述第一站点在所述第一时间间隔内确定所述PPDU为所述OBSS PPDU，将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限，包括：
    所述第一站点在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，并将第二监测门限作为所述第一站点在后续的信道监测过程中的PPDU监测门限；
    所述第一站点在所述第一时间间隔内确定所述信道处于空闲状态，包括：
    所述第一站点在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
  9. 权利要求1至8任一所述的方法，其特征在于，所述第二监测门限为OBSS PPDU监测门限。
  10. 一种基于空间重用的退避设备，其特征在于，包括：
    收发模块，用于在信道监测过程中侦听到信道中有物理层协议数据单元PPDU传输；
    处理模块，用于在确定所述侦听到的PPDU的接收信号强度不小于第一监测门限后，中止所述信道监测过程，并解调所述PPDU得到第一数据；所述第一监测门限为所述设备在所述信道监测过程中采用的PPDU监测门限；所述第一数据包括所述PPDU的信令字段承载的小区指示信息和/或介质访问控制MAC字段中的地址信息；
    所述处理模块还用于，在得到所述第一数据之后的第一时间间隔内，若根据所述第一数据，确定所述PPDU为交叠基础服务集OBSS PPDU，则将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限，所述第二监测门限值大于所述第一监测门限值，所述第一时间间隔小于一个分布式帧间间隔DIFS；并在所述第一时间间隔之后进行退避；
    所述收发模块还用于，当退避完成后若信道处于空闲状态，则开始发送数据。
  11. 如权利要求10所述的设备，其特征在于，若所述信道监测过程为点帧间间隔PIFS或DIFS或扩展帧间间隔EIFS或仲裁帧间间隔AIFS中的信道监测过程，则所述第一时间间隔包括至少一个将所述第一数据从物理层传输到MAC层的延迟D1和至少一个所述MAC层处理所述第一数据的延迟M1和至少一个进行一次信道评估CCA检测所需要的时长CCAdel；
    所述处理模块，用于：
    在所述第一时间间隔内确定所述信道处于空闲状态后，在所述第一时间间隔之后进行退避。
  12. 如权利要求11所述的设备，其特征在于，所述处理模块，用于：
    根据退避时长CW1，进行退避，其中，CW1＜CW2或CW1＝α*CW2， CW2为不进行空间重用的退避时长，0＜α＜1，且α正比于所述PPDU的接收信号强度；
    或者
    根据当前的竞争窗口随机选择的退避时长，进行退避；或者
    根据活跃站点的数量或空间重用SR活跃站点的数量，确定退避过程所使用退避时长CW1；所述CW1满足下列公式：
    Figure PCTCN2016106983-appb-100002
    其中，Nsta表示所述活跃SR站点的数量或所述活跃站点的数量的加权平均值，所述活跃SR站点为与所述设备互为OBSS的站点，所述活跃站点为所述设备能够帧听到PPDU的站点。
  13. 如权利要求10所述的设备，其特征在于，若所述信道信测过程为退避过程中的信道监测过程，则所述第一时间间隔包括至少一个D1和至少一个M1。
  14. 如权利要求13所述的设备，其特征在于，所述处理模块，用于：
    根据所述信道监测过程的中止时刻，确定剩余的退避时长，并将所述CW1设置为所述剩余的退避时长；并根据所述剩余的退避时长，进行退避。
  15. 如权利要求13所述的设备，其特征在于，所述处理模块，用于：
    根据所述信道监测过程的中止时刻，确定剩余的退避时长；根据所述PPDU的接收信号强度调整所述剩余的退避时长，得到新的退避时长；并根据新的退避时长，进行退避；
    所述退避时长与所述剩余的退避时长满足下列公式：
    New_BO＝Remaining_BO*α；
    其中，New_BO为所述新的退避时长，Remaining_BO为所述剩余的退避时长，其中0＜α＜1，且α正比于所述PPDU的接收信号强度。
  16. 如权利要求10至15任一所述的设备，其特征在于，若所述第一时间间隔为一个空间重用帧间隔SRIFS，所述SRIFS包括一个D1、一个M1和 一个进行一次信道评估CCA检测所需要的时长CCAdel；
    所述处理模块，用于包括：
    在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，则将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限；
    所述处理模块，用于：
    在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
  17. 如权利要求10至15任一所述的设备，其特征在于，若所述第一时间间隔为一个PIFS；
    所述处理模块，用于：
    在所述第一时间间隔的D1和M1内确定所述PPDU为所述OBSS PPDU，并将第二监测门限作为所述设备在后续的信道监测过程中的PPDU监测门限；
    所述处理模块，用于：
    在CCAdel内确定所述信道处于空闲状态，其中，在所述PPDU的接收信号强度小于所述第二监测门限时，所述信道处于空闲状态。
  18. 如权利要求10至17任一所述的设备，其特征在于，所述第二监测门限为OBSS PPDU监测门限。
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