CN107708184B

CN107708184B - Communication access method, access point and site

Info

Publication number: CN107708184B
Application number: CN201610647623.7A
Authority: CN
Inventors: 史桢宇; 黄磊; 吴霁
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2016-08-09
Filing date: 2016-08-09
Publication date: 2020-09-29
Anticipated expiration: 2036-08-09
Also published as: WO2018028314A1; CN107708184A

Abstract

The embodiment of the invention discloses a communication access method, which comprises the following steps: the AP determines M directional beam directions of N STAs needing uplink data transmission relative to the AP, divides the AP contention access time into X time periods according to the M directional beam directions, and sequentially adjusts the AP directional beam direction into a directional beam direction corresponding to each time period according to the X time periods so as to receive a contention access request sent by at least one STA. Therefore, the AP pointedly adjusts the directional beam direction continuously according to the divided time periods to receive the competition access requests sent by the STAs in different directions, and the AP adopts a directional beam receiving mode, so that the AP improves the coverage transmission distance of the AP on the premise that a plurality of surrounding STAs can establish communication access.

Description

Communication access method, access point and site

Technical Field

The present invention relates to the field of communications, and in particular, to a method for communication access, an access point, and a station.

Background

The mobile communication mainly includes communication between an Access Point (AP) and a Station (STA), where the communication established between the AP and the STA mainly includes contention Access by multiple STAs, for example, the AP is a base Station and the STA is a terminal, and when multiple terminals need to transmit uplink data, communication connection needs to be established with the base Station in a contention Access manner. With the increasing requirements of data transmission rate, communication quality, etc. for mobile communication nowadays, the existing frequency bands for mobile communication have become very crowded. However, in the millimeter wave band of 6-300GHz, there is still a large amount of spectrum resources that have not been allocated for use. The high frequency band represented by the millimeter wave frequency band is mainly applied to indoor short-distance communication scenes. In outdoor scenes, due to the characteristic of large path loss of the high frequency band, the application of the high frequency band in the outdoor scenes is severely restricted. The higher the frequency band, the smaller the distance it can transmit, for example, a cell radius of 25m to 100m can be covered for a system using a 72GHz band, and a cell radius of 50 m to 200 m can be covered for a system using a frequency band below 30 GHz. In a high-frequency system, a large-scale array antenna can be adopted to form a directional beam with high gain, so that high path loss caused by a high frequency band can be overcome, and the transmission distance of a link is increased. However, if the directional beam is used for communication transmission, the coverage direction of the AP is relatively small, for example, if the directional beam is used at an angle of 30 degrees, the range of the communication transmission can be only covered by the angle of 30 degrees even if the transmission distance is relatively long.

Therefore, in the existing IEEE802.11ad standard, a high-frequency omni-directional beam is used to implement transceiving, for example, in an uplink phase, an AP receives a contention access request sent to the AP by surrounding STAs by using the omni-directional beam, and although the AP can cover the surrounding STAs by using the omni-directional beam, the transmission distance is short due to the characteristic that the path loss of the high-frequency channel is large, so that STAs far away from the AP cannot access the AP, thereby limiting the communication coverage of the AP.

Disclosure of Invention

The invention provides a communication access method, an access point and a station, which are used for improving the communication coverage of an Access Point (AP).

A first aspect of the present invention provides a method for communication access, including:

the access point AP determines M directional beam directions of N stations STA needing uplink data transmission relative to the AP, wherein N is larger than or equal to M, and one directional beam direction in the M directional beam directions comprises one or more STAs. The AP divides a contention access time period of the AP into X time periods according to the M directional beam directions, the X time periods correspond to the M directional beam directions, and X is greater than or equal to M, that is, each directional beam direction corresponds to one or more time periods. And the AP sequentially adjusts the directional beam direction of the AP to the directional beam direction corresponding to each time slot according to the X time slots so as to receive a competition access request sent by at least one STA in the N STAs.

Therefore, the AP pointedly adjusts the directional beam direction continuously according to the divided time periods to receive the competition access requests sent by the STAs in different directions, and the AP adopts a directional beam receiving mode, so that the coverage distance of the AP is increased on the premise that the AP can establish communication access by a plurality of surrounding STAs.

In a possible implementation manner, the AP divides contention access time of the AP into X time periods according to M directional beam directions, which may be:

the AP averagely divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein the X time periods are in one-to-one correspondence with the M directional beam directions.

For example, if M is 4, the number of time periods divided by the AP is also 4, and the length of each of the 4 time periods is consistent, and one time period corresponds to one directional beam direction. Therefore, the contention access time which can be used by the STA in each directional beam direction is equal, and the use balance rate of the contention access time is improved.

In another possible implementation manner, the AP divides contention access time of the AP into X time periods according to the M directional beam directions, which may further be:

the AP divides the AP contention access time into X time periods according to the M directional beam directions and the number of STAs contained in each directional beam direction, wherein the longer the time period divided by the directional beam direction containing the larger number of STAs is, the X is greater than or equal to M.

Since some directional beam directions may include a plurality of STAs, and some directional beam directions include only one STA, if the time period is divided evenly, some time periods may be insufficient, and some time periods have surplus, therefore, the AP may divide the time period according to the number of STAs included in each directional beam direction, if the number of STAs included in the directional beam direction is large, the divided time period is long, and if the number of STAs included in the directional beam direction is small, the divided time period is short. Thus, the resource utilization rate of the competitive access time is improved.

In another possible implementation manner, before the AP sequentially adjusts the directional beam direction of the AP to the directional beam direction corresponding to each time period according to X time periods, the method may further include:

and the AP sends the information of each time period in the X time periods to the STA in the corresponding directional beam direction, and is used for indicating the STA to send a competition access request to the AP according to the received information of the time periods.

In the communication access mechanism, the STA monitors the channel state of the AP in real time, and as long as the channel of the AP is monitored to be in an idle state, a contention access request is sent to the AP to request access and send uplink data. Therefore, after the time period is divided, the AP sends the information of the time period to the STA in the direction of the corresponding directional beam, so that the STA can know in which time period the STA can send the contention access request and can be received by the AP, thereby reducing the STA from sending the unnecessary contention access request and saving the power consumption of the STA.

In another possible implementation manner, before the AP determines M directional beam directions of N stations STA that need to perform uplink data transmission relative to the AP, the method may further include:

the AP determines that the competition access request received in the preset time through the omnidirectional beam is less than a preset threshold value.

Although the transmission distance of the omnidirectional beam is relatively short, the reception range of the omnidirectional beam is relatively wide, and therefore, the AP may first adopt the omnidirectional beam to receive the contention access request, and if the contention access request received within a certain time is relatively small, the position where most STAs are located may be relatively far from the AP, and thus the AP may adopt the directional beam to perform the contention access request. Therefore, the success rate of the STA to access the AP is improved.

A second aspect of the present invention provides a method for communication access, including:

the method comprises the steps that a station STA determines the sending direction of an access point AP relative to the STA, the STA receives indication information sent by the AP, the indication information comprises information of a time period of the STA in the AP competition access time, the information of the time period is information of a time period corresponding to the sending direction in X time periods, the X time periods are time periods divided by the AP according to the AP competition access time period, and the STA sends a competition access request to the AP in the sending direction according to the received information of the time periods.

In the communication access mechanism, the STA monitors the channel state of the AP in real time, and as long as the channel of the AP is monitored to be in an idle state, a contention access request is sent to the AP to request access and send uplink data. Therefore, after the time period is divided, the AP sends the information of the time period to the STA in the direction of the corresponding directional beam, and thus, the STA sends the contention access request to the AP according to the received information of the time period, thereby reducing the sending of unnecessary contention access requests by the STA and saving the power consumption of the STA.

A third aspect of the present invention provides an access point, AP, comprising:

the determining unit is configured to determine M directional beam directions of N stations STA requiring uplink data transmission relative to the AP, where N is greater than or equal to M, and one directional beam direction of the M directional beam directions includes one or more STAs.

The device comprises a dividing unit, a receiving unit and a processing unit, wherein the dividing unit is used for dividing a contention access time period of the AP into X time periods according to the M directional beam directions, the X time periods correspond to the M directional beam directions, X is larger than or equal to M, and each directional beam direction corresponds to one or more time periods.

And the adjusting unit is used for sequentially adjusting the directional beam direction of the AP to the directional beam direction corresponding to each time slot according to the X time slots so as to receive the contention access request sent by at least one STA in the N STAs.

A fourth aspect of the present invention provides a station STA, including:

a determining unit, configured to determine a transmission direction of the AP with respect to the STA.

A receiving unit, configured to receive indication information sent by an AP, where the indication information includes information of a time period of an STA in a contention access time of the AP, the information of the time period is information of a time period corresponding to the sending direction in X time periods, and the X time periods are time periods divided by the AP according to the contention access time period of the AP.

And a sending unit, configured to send a contention access request to the AP in the sending direction according to the received information of the time period.

A fifth aspect of the present invention provides an access point AP, including: the system comprises a processor, a memory and a transceiver, wherein the processor, the memory and the transceiver are connected through a bus, the memory stores computer instructions, and the processor is used for realizing the following method by executing the computer instructions:

determining M directional beam directions of N stations STA (station) needing uplink data transmission relative to the AP;

dividing the AP competition access time period into X time periods according to the M directional beam directions;

and sequentially adjusting the directional beam direction corresponding to each time period according to the X time periods so as to receive a contention access request sent by at least one STA in the N STAs.

A sixth aspect of the present invention provides a station STA, including: the system comprises a processor, a memory and a transceiver, wherein the processor, the memory and the transceiver are connected through a bus, the memory stores computer instructions, and the processor is used for realizing the following method by executing the computer instructions:

determining a transmission direction of an Access Point (AP) relative to the STA;

the method comprises the steps that a transceiver is controlled to receive indication information sent by an AP, the indication information comprises information of a time period of an STA in the AP competitive access time, the indication information comprises information of a time period corresponding to a sending direction in X time periods, and the X time periods are time periods divided by the AP according to the AP competitive access time period;

and sending a competition access request to the AP in a sending direction according to the received information of the time period.

A seventh aspect of the present invention provides a storage medium storing computer instructions for implementing the method for communication access in the first or second aspect.

Drawings

Fig. 1 is a schematic diagram of an architecture of a communication access method according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a structure of a beacon interval in an embodiment of the present invention;

fig. 3 is a flowchart illustrating a method for communication access according to an embodiment of the present invention;

fig. 4 is a schematic diagram of an access point performing average time division according to an embodiment of the present invention;

fig. 5 is a schematic diagram of an access point performing integer-times time division according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating an embodiment of an access point randomly partitioning time periods;

FIG. 7 is a diagram illustrating an embodiment of time slots divided by the number of access points;

fig. 8 is another flowchart illustrating a method for communication access according to an embodiment of the present invention;

FIG. 9 is a diagram of an access point in an embodiment of the present invention;

FIG. 10 is a schematic view of a station in an embodiment of the invention;

fig. 11 is another diagram of an access point in an embodiment of the invention;

fig. 12 is another schematic diagram of a station in an embodiment of the invention.

Detailed Description

The embodiment of the invention provides a communication access method and a communication access device, which are used for improving the communication coverage of an Access Point (AP).

Referring to fig. 1, fig. 1 is a schematic diagram of a system architecture for communication access according to an embodiment of the present invention. In the system architecture, the access point AP and at least one station STA are included, and a transmission unit for communication between the STA and the AP is a Beacon Interval (full name: Beacon Interval, abbreviated as BI), as shown in fig. 2. A BI can be further divided into a header (Beacon Head Interval, BHI) phase and a Data Transmission (DTI) phase. In the BHI stage, the AP sends broadcast information, connects with the STA in the range (English full name: association with), and completes the beam training between the AP and the STA. The beam training refers to that the AP performs detection training in each beam direction to find a beam with the best channel quality for transmission with the STA, where the beam with the best channel quality is used for data transmission, and the channel quality may be specifically determined by the level of the reference signal power. The beam training may specifically refer to the definition of the ieee802.11ad standard, and after the beam training, both the AP and the STA know the beam direction of the STA.

After the BHI phase is finished, the DTI phase is entered, where the DTI phase is a data transmission phase, and the data transmission in the DTI phase generally includes two Access transmission situations, as shown in fig. 2, the DTI phase includes a user Contention Access (hereinafter, referred to as content-based Access Period, abbreviated as CBAP) and a Scheduled Service Access (hereinafter, referred to as Scheduled Service Period, abbreviated as SP). In the CBAP phase, each STA contends to obtain an access opportunity, a plurality of STAs acquire channel resources by sending a Request To Send (RTS), where the RTS/CTS includes information such as the serial number ID of the STA and the length of data to be sent. When the AP receives RTS of a certain STA, reading ID of the STA, calculating whether enough time is available in the remaining CBAP time to finish the data transmission which needs to be sent by the STA, if the confirmation can be sent, adjusting the wave beam to the direction of the STA and sending information (clear to send, CTS) which is allowed to be sent, and indicating that the STA can send uplink data; otherwise, sending the rejection message (English to send, English abbreviation: DTS). And if other STAs send RTS, the other STAs do not receive CTS within a preset time period or receive DTS, which indicates that resources are not robbed, and continue to send RTS after waiting for a preset time period.

In the embodiment of the invention, the AP uses a high-frequency band of millimeter waves of 6-300GHz for data transmission, a directional beam is adopted for data reception, and the AP enhances the transmitted signals by adjusting the amplitude modulation and the phase modulation on the array antenna, thereby forming the directional beam. The AP in the embodiment of the present invention may be a base station, and the STA may be a terminal or other user equipment having a function of accessing to the base station.

Referring to fig. 3, an embodiment of a method for communication access in the embodiment of the present invention includes the following steps:

101. an Access Point (AP) determines M directional beam directions of N Stations (STA) needing uplink data transmission relative to the AP.

In order to increase the gain of the received beam of the AP and increase the data transmission distance of the AP, in the embodiment of the present invention, the AP receives data by using a directional beam, and since the coverage direction of the directional beam is limited, the AP needs to continuously adjust the direction of the directional beam in order to make STAs around the AP have an opportunity to access the AP. If the AP performs 360-degree rotation polling to adjust the direction of the directional beam, it is obvious that time resources are wasted, because STAs which need to perform uplink data transmission around the AP are not necessarily uniformly distributed, it is likely that a plurality of STAs need to perform uplink data transmission in one directional beam direction, and there are directional wave velocity directions in which no STA needs to perform uplink data transmission. Therefore, in the embodiment of the present invention, before the STA performs data transmission, the AP determines M directional beam directions of N STAs which need to perform uplink data transmission relative to the AP, where N is a positive integer greater than or equal to 1, and M is a positive integer greater than or equal to 1. Specifically, the AP may perform beam training with surrounding STAs in advance, so as to obtain a directional beam direction of the STA requiring uplink data transmission relative to the AP.

Here, the directional beam direction is a directional beam receiving direction, and is a direction in which the AP receives a contention access request transmitted by the STA and performs data transmission with the STA. And the direction of the training beam employed by the AP in beam training with surrounding STAs may not be the same as the directional beam reception direction. For example, when the AP performs beam training with surrounding STAs, in order to reduce the training time, the angle of the formed beam may be made larger, for example, the rotation polling training may be performed in a beam training direction with an angle of 60 °, and in order to improve the beam gain and increase the data transmission distance of the AP, the angle of the directional beam receiving direction adopted by the AP during the data transmission phase may be smaller, for example, set to be 15 ° relative to the angle of the training beam. For example, after the AP performs beam training, it is determined that two STAs in the 0 ° to 15 ° direction need to perform uplink data transmission, and two STAs in the 15 ° to 30 ° direction need to perform uplink data transmission.

102. And the AP divides the competition access time period of the AP into X time periods according to the M directional beam directions.

In the data transmission phase, one or more CBAP periods are generally included, and the contention access period may be one CBAP period in the data transmission phase or all CBAP periods in the data transmission phase. In the CBAP time period, STAs which need to perform uplink data transmission around the AP may send a contention access request RTS to the AP to request access to the AP, thereby sending uplink data to the AP. In the embodiment of the invention, the AP adopts the directional receiving beam, so that the receiving beam formed by the AP at a certain moment can only cover the area in one direction, but not all directions. For example, the directional reception beam formed by the AP is a 15 ° angle beam, at a certain time, the 15 ° angle beam can only receive the contention access request RTS sent by the STA in the area covered by the AP, and can hardly receive the RTS sent by the STA in other areas. Therefore, in order to enable all STAs which need to perform uplink data transmission around the AP to have an opportunity to contend for access to the AP in the CBAP contention access period, the AP divides the contention access period CBAP into X periods according to the M directional beam directions, and the X periods and the M directional beam directions correspond to each other, so that the AP polls and adjusts the directional beam direction corresponding to each period according to the X periods to receive the contention access request sent by the STA.

Referring to fig. 4, wherein B1-B4 represent the directional beam directions corresponding to different time periods, here the distance is 4 directional beam directions. In a possible implementation manner, the AP divides contention access time of the AP into X time periods according to M directional beam directions, which may specifically be: the AP averagely divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein X is equal to M; and the X time periods correspond one-to-one to the M directional beam directions.

In this implementation, the AP equally divides the contention access time according to the number of determined directional beam directions, for example, the AP determines that there are 4 STAs which need to perform uplink data transmission with respect to the directional beam directions of the AP, which are respectively the angular directions of 0 ° to 15 °, 15 ° to 30 °, 30 ° to 45 °, and 45 ° to 60 °. And the contention access period is 10ms, then the AP divides the contention access period of 10ms into 4 periods on average according to 4 directional beam directions, which are 0ms-2.5ms, 2.5ms-5ms, 5ms-7.5ms and 7.5ms-10, respectively. The corresponding relation can be one-to-one correspondence according to the angle and the time sequence, and can also be in disorder correspondence, for example, a 0ms-2.5ms time period corresponds to the 15-30 degree angle direction, a 2.5ms-5ms time period corresponds to the 30-45 degree angle direction, a 5ms-7.5ms time period corresponds to the 0-15 degree angle direction, and a 7.5ms-10 time period corresponds to the 45-60 degree angle direction. By the time period dividing mode and the corresponding mode of the time period and the directional beam direction, the AP performs relatively average comparison when polling and adjusting the receiving direction of the directional beam, and the AP scans and receives the competition access request sent by the STA in each directional beam direction according to the average time period, so that the probability of the STA in each direction competing and accessing the AP is almost the same.

Referring to fig. 5, in another possible implementation manner, dividing contention access time of an AP into X time periods according to M directional beam directions by the AP may be: the AP averagely divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein X is integral multiple of M; each M time segments of the X time segments corresponds to M directional beam directions.

In this implementation, the AP divides the contention access time period into a plurality of small time periods, and the plurality of time periods correspond to one directional beam direction, and each M time periods correspond to M directional beam directions, and optionally, the directional beam directions corresponding to the time periods every other M time periods are the same. For example, the AP determines that the directional beam directions of STAs which need to perform uplink data transmission are 4, which are 0 ° to 15 ° angular directions, 15 ° to 30 ° angular directions, 30 ° to 45 ° angular directions, and 45 ° to 60 ° angular directions, respectively, and the first contention access period is 10ms, then the AP may averagely divide the contention access period of 10ms into 16 periods, where the length of each period is 0.625ms, the 16 periods are sorted according to a time sequence, and the sequence numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16, and then the periods 1, 5, 9, and 13 correspond to one of the 4 directional beam directions, such as 0 ° to 15 ° angular directions; 2. the 6, 10, 14 time periods correspond to one of the 4 directional beam directions, such as the 15 ° -30 ° angular direction; 3. the 7, 11, 15 time segments correspond to one of the 4 directional beam directions, such as a 30 ° -45 ° angular direction; 4. the 8, 12, 16 time segments correspond to one of the 4 directional beam directions, such as a 45 ° -60 ° angular direction. Thus, the AP adjusts the receiving direction of the directional beam once every 0.625ms, polling scanning in all directions is completed once every 2.5ms period, after four periods, the contention access period is ended, and then the STA in one direction has four chances to access the AP. By the mode of periodically scanning and receiving the STA to send the request RTS for contention access, each STA has the opportunity of accessing the AP for multiple times in a contention access time period, and the probability of accessing the AP by the STA is improved.

Referring to fig. 6, in another possible implementation manner, dividing contention access time of an AP into X time periods according to M directional beam directions by the AP may be: the AP randomly divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein X is larger than or equal to M; one or more of the X time periods correspond to one of the M directional beam directions.

In this implementation, the AP randomly divides the contention access time period into a plurality of time periods, and one or more time periods correspond to one directional beam direction. For example, the AP determines that the directions of directional beams of STAs which need to perform uplink data transmission are 4 relative to the AP, and are respectively an angular direction of 0 ° to 15 °, an angular direction of 15 ° to 30 °, an angular direction of 30 ° to 45 °, and an angular direction of 45 ° to 60 °, and the first contention access period is 10ms, so that the AP may randomly divide the 10ms contention access period into 5 periods, where the lengths of the 7 periods are different, for example, the 1 st period is 2ms, the 2 nd period is 4ms, the 3 rd period is 1ms, the 4 th period is 1ms, and the 5 th period is 2 ms. Two time periods correspond to the same directional beam direction, for example, the 1 st time period and the 3 rd time period correspond to the angle direction of 0-15 degrees, the 2 nd time period corresponds to the angle direction of 15-30 degrees, the 3 rd time period corresponds to the angle direction of 30-45 degrees, and the 4 th time period corresponds to the angle direction of 45-60 degrees. In order to allow the AP to receive the contention access request at least once in each directional beam direction in the contention access period, the directional beam directions corresponding to the divided periods need to include directional beam directions of all STAs which need to perform uplink data transmission with respect to the AP.

Referring to fig. 7, in another possible implementation manner, dividing contention access time of an AP into X time periods according to M directional beam directions by the AP may be: the AP divides the AP contention access time into X time periods according to the M directional beam directions and the number of STAs contained in each directional beam direction, wherein the longer the time period divided by the directional beam direction containing the larger number of STAs is, the X is greater than or equal to M.

In this implementation, the AP may further divide the length of the time period according to the number of STAs included in each directional beam direction, for example, the AP determines that the STAs which need to perform uplink data transmission are 4 relative to the directional beam direction of the AP, and the STA includes an angular direction of 0 ° -15 °, an angular direction of 15 ° -30 °, an angular direction of 30 ° -45 °, and an angular direction of 45 ° -60 °, the contention access time period of the AP is 10ms, and the AP obtains that the angular direction of 0 ° -15 ° includes 2 STAs which need to perform uplink data transmission, the angular direction of 15 ° -30 ° includes 1 STA which needs to perform uplink data transmission, the angular direction of 30 ° -45 ° includes 4 STAs which need to perform uplink data transmission, the angular direction of 45 ° -60 ° includes 3 STAs which need to perform uplink data transmission, and then the AP may divide the 10ms time period into 2ms respectively, 1ms, 4ms, and 3ms, wherein the 2ms time period corresponds to an angular orientation of 0-15 °, the 1ms time period corresponds to an angular orientation of 15-30 °, the 4ms time period corresponds to an angular orientation of 30-45 °, and the 3ms time period corresponds to an angular orientation of 45-60 °. Therefore, the time period allocated to the direction of the directional beam containing more STAs is longer, and the time period allocated to the direction of the directional beam containing less STAs is shorter, so that the allocation of the time period is more reasonable and balanced, and the resource utilization rate of the competitive access time is improved.

103. And the AP sequentially adjusts the direction of the directional beam corresponding to each time slot according to the X time slots so as to receive a competition access request sent by at least one STA in the N STAs.

After the AP divides the contention access time of the AP into X time periods according to the M directional beam directions, the AP needs to sequentially adjust the directional beam directions corresponding to each time period according to the X time periods, so as to be used for the contention access request sent by the STA. For example, the AP equally divides the first contention access time into X time periods according to M directional beam directions, where X is equal to M, and the X time periods are in one-to-one correspondence with the M directional beam directions. The AP adjusts the directional beam direction to a first directional beam direction for a first time period, to a second directional beam direction for a second time period, and so on, to contend for receipt of the access request in each direction. It should be noted that, in the embodiment of the present invention, as long as the STA that needs to perform uplink data transmission detects that the channel of the AP is in an idle state, that is, the AP does not perform data transmission at this time, the STA may send a contention access request to the AP, regardless of whether the beam direction of the directional beam adjusted by the AP is the direction in which the STA is located, so that the probability of successful contention access of the STA is also increased.

As will be illustrated below, the AP determines that the STAs that need to perform uplink data transmission are in 2 directional beam directions, which are 0 ° -15 ° angular directions and 15 ° -30 ° angular directions, respectively, with respect to the AP. And the contention access period of the AP is 10ms, the AP equally divides the contention access period of 10ms into 2 periods according to 2 directional beam directions, which are 0ms-5ms and 5ms-10ms, respectively, and there are two STAs in each directional beam direction that need to perform uplink data transmission, which are STA1, STA2, STA3, and STA4, respectively. In a time period of 0ms to 5ms, the AP adjusts the directional beam direction to be 0 ° to 15 ° and the channel of the AP is in an idle state, so each STA sends a contention access request RTS to the AP, because STA3 and STA4 are not in the angle direction of 0 ° to 15 °, the AP is almost impossible to receive RTS sent by STA3 and STA4, and after a period of time, for example, 2ms, STA3 and STA4 do not receive CTS or DTS fed back by the AP, STA3 and STA4 continue to send RTS to the AP for contention access. Since STA1 and STA2 are in the angle direction of 0-15 °, the RTS sent by STA1 and STA2 is likely to be received by the AP, for example, the AP first receives the RTS sent by STA1, the data length that STA1 included in the RTS sent by STA1 needs to transmit is 20 bits, the time that the AP needs to calculate the 20 bits according to the network transmission speed is 2ms, and 5ms still remains in the time period, so that it is considered that the data transmission of STA1 can be completed in the 5ms time period, and therefore CTS is sent to STA 1. When the AP subsequently receives the RTS from STA2, the AP may not feed back any information to STA2 because STA2 will continue to send RTS to the AP after waiting for a predetermined period of time, and may also feed back a DTS to STA2 indicating that data transmission with STA2 is not possible at this time. After the AP and STA1 complete data transmission, the AP continues to receive an RTS sent by STA2, where the RTS contains 40 bits of data length that STA2 needs to transmit, the time that the AP calculates the 40 bits according to the network transmission speed is 4ms, and only 3ms remains in the time period, at this time, the AP may send a DTS to STA2 to indicate that data transmission with STA2 cannot be performed, and when the AP waits for a 5ms-10ms period, the directional beam direction is adjusted to 15 ° -30 ° angular direction; alternatively, the AP may send CTS to STA2 to complete data transmission with STA2, and the time period of the next time period, i.e., 5ms to 6ms, is occupied by the exceeding 1ms, and the time period for the AP to adjust the beam direction of the directional beam is 6ms to 10 ms.

In the embodiment of the invention, the AP determines M directional beam directions of N STAs needing uplink data transmission relative to the AP, divides the competition access time of the AP into X time periods according to the M directional beam directions, and sequentially adjusts the directional beam direction of the AP into the directional beam direction corresponding to each time period according to the X time periods so as to receive the competition access request sent by at least one STA. Therefore, the AP pointedly adjusts the directional beam direction continuously according to the divided time periods to receive the competition access requests sent by the STAs in different directions, and the AP adopts a directional beam receiving mode, so that the AP improves the coverage transmission distance of the AP on the premise that a plurality of surrounding STAs can establish communication access.

Optionally, with reference to the embodiment of fig. 3, in an optional embodiment, before the AP sequentially adjusts the directional beam direction corresponding to each time period according to X time periods, the method for communication access further includes:

In an optional embodiment, after the AP divides X time periods and determines a directional beam direction corresponding to each time period, information of each time period may also be sent to the STA in the corresponding directional beam direction, where the information of the time period includes a start time and an end time of the time period, or includes a start time and a duration of the time period. For example, the AP determines that the directional beam directions of the STAs needing uplink data transmission are 2, which are respectively the angular directions of 0 ° to 15 ° and the angular directions of 15 ° to 30 ° relative to the AP, and there are two STAs needing uplink data transmission in each directional beam direction, which are respectively STA1, STA2, STA3 and STA 4. The first competition access time period is 10ms, the AP averagely divides the 10ms competition access time period into 2 time periods according to 2 directional beam directions, wherein the 2 time periods are respectively 0ms-5ms and 5ms-10ms, the 0ms-5ms time period corresponds to an angle direction of 0-15 degrees, and the 5ms-10ms time period corresponds to an angle direction of 15-30 degrees. The AP may further send the start time 0ms and the duration 5ms of the time period of 0ms to 5ms to the STA1 and the STA2, and send the start time 5ms and the duration 5ms of the time period of 5ms to 10ms to the STA3 and the STA4, so that, in the time period of 0ms to 5ms, only the STA1 and the STA2 under the directional beam direction corresponding to the time period send a contention access request to the AP, but the STA3 and the STA4 do not send the contention access request, and in the time period of 5ms to 10ms, only the STA3 and the STA4 under the directional beam direction corresponding to the time period send a contention access request to the AP, but the STA1 and the STA2 do not send the contention access request, so that the STA sends the contention access request to the AP more specifically, thereby reducing the sending of meaningless requests and reducing power consumption of the STA.

Optionally, the access point AP may also send the information of each time period to all STAs in a broadcast manner.

In another optional manner, the AP broadcasts the information of each of the X time periods and the adjustment sequence of the AP to the directions of the M directional beams to the N STAs, so as to instruct the N STAs to send contention access requests to the AP according to the information of each time period and the adjustment sequence.

Because the AP has obtained the directional beam direction of each STA relative to the AP during the beam training phase, each directional beam direction has a unique identification ID, after the AP divides the time period, the AP allocates the direction corresponding to each time period, and the STA in each direction naturally corresponds to the divided time period, so that the AP determines the adjustment sequence of the unique directional beam direction according to the front and rear sequence of the time periods. Therefore, the AP may broadcast the divided time periods and the unique adjustment sequence to all STAs, and since the STA knows the ID of the directional beam in which the STA is located, it can know in which time period the STA can send uplink data transmission, and the information of each time period is also sent to all STAs, all STAs can calculate when the time period corresponding to the directional beam direction in which the STA is located starts from, and the duration of the time period, so that a contention access request can be sent to the AP in the time period.

For example, after determining that there are STAs in four directional beam directions that need to perform uplink data transmission, the sequence numbers of the directional beam directions are 1, 2, 3, and 4, respectively, the STA1 needs to perform uplink data transmission in the directional beam direction with the sequence number of 1, the directional beam direction with the sequence number of 2 corresponds to the STA2, the directional beam direction with the sequence number of 3 corresponds to the STA3, and the directional beam direction with the sequence number of 3 corresponds to the STA4, respectively, and after the beam training, the AP sends the

sequence numbers

1, 2, 3, and 4 in the directional beam directions to the STA corresponding to each sequence number. The AP divides a contention access time period with a length of 10ms into 4 time periods, which are 0ms-2ms, 2ms-5ms, 5ms-8ms, and 8ms-10ms, respectively, and then makes each time period correspond to a directional beam direction, for example, each time period corresponds to a reverse direction, the directional beam direction with a sequence number of 1 corresponds to the 8ms-10ms time period, the directional beam direction with a sequence number of 2 corresponds to the 5ms-8ms time period, the directional beam direction with a sequence number of 3 corresponds to the 2ms-5ms time period, and the directional beam direction with a sequence number of 4 corresponds to the 0-2ms time period. Since time is not reversible, the sequence of time periods does not change, necessarily from 0ms to 10ms, and then the only sequence in which the AP adjusts the directional beam direction, i.e. the adjustment sequence of 4321, is determined. After the AP broadcasts the time domain information of each time period (the start time and duration of each time period) and the adjustment sequence 4321 of the AP adjusting the directional beam direction to all STAs, the STA can determine which time period it can send a contention access request, such as STA1, in which the directional beam direction is "1", and the adjustment sequence of the AP is 4321, so STA1 can send the contention access request in the last time period, i.e., 8ms-10 ms.

Optionally, before the AP determines that M directional beam directions of N STAs requiring uplink data transmission are relative to the AP, the communication access method further includes:

the AP determines that the competition access request received in the preset time through the omnidirectional wave beam is less than a preset threshold value.

The above has described the case where the AP performs data reception using an omni-directional beam and the case where the AP performs data reception using a directional beam. The AP adopts the omnidirectional wave beam to receive data, and has the advantages that the probability of the STA around the AP competing to access the AP is relatively average, and because the AP receives the data in the omnidirectional direction at any moment, the AP is likely to receive the competition access request sent by the STA in any direction; but has the disadvantage of using omni-directional beam reception resulting in a shorter distance over which the AP can transmit data. The AP receives data by using directional beams, which has the advantage of longer transmission distance and the disadvantage of similar probability of each STA accessing the AP without using omni-directional beams. In an actual application scenario, for example, a transmission distance of an AP for data reception by using an omnidirectional beam is 100m, a transmission distance of an AP for data reception by using a directional beam is 120m, the AP first receives data by using the omnidirectional beam, and if contention access requests received by the AP within 1 minute are 2, there are only 2 STAs which need to perform data transmission within a 100m range, and other more STAs are located outside the 100m range, so that the AP receives data by using the directional beam, and can receive contention access requests sent by STAs within the 120m range.

Referring to fig. 8, another embodiment of the method for communication access in the embodiment of the present invention includes:

201. the station STA determines the transmission direction of the access point AP relative to the STA.

As described in the embodiment of fig. 3, the AP determines, according to the beam training mode, the directional beam direction of the STA that needs to perform uplink data transmission with respect to the AP, and likewise, the STA determines the transmission direction of the AP with respect to the STA through the beam training mode. On the other hand, since the STA performs data transmission by adjusting the antenna, and the adjustment of the transmission direction of the antenna can increase the transmission gain of the STA and increase the transmission power, the STA determines the transmission direction of the AP with respect to the STA when performing beam training.

202. And the STA receives indication information sent by the AP, wherein the indication information is information of a time period of the STA in the contention access time of the AP.

The information of the time period may include a start time and an end time of the time period, such as a time of 2ms and an end time of 4 ms; or the information of the time period may include a start time and a duration of the time period, such as a start time of 2ms and a duration of 2 ms. Since each time period corresponds to a directional beam direction of the AP, there must be a time period corresponding to a transmission direction for the STA. For example, the directional beam direction of the STA relative to the AP is a direction at an angle of 15-30, and the first direction of the AP relative to the AP is a direction at an angle of 30-60, which are both relative directions.

In another implementation, the indication information may include information of at least two time periods and an adjustment order of the AP to at least two directional beam directions.

Detailed description referring to an alternative embodiment of the embodiment of fig. 3, the access point AP may also send the information of each time period to the content of the STA in a broadcast manner.

203. And the STA sends a competition access request to the AP in the sending direction according to the received information of the time period.

After obtaining the information of the time period in the sending direction, the STA sends a contention access request to the AP in the sending direction in the time period, and after accessing the AP, may send data to be uplinked to the AP.

Optionally, with reference to the embodiment of fig. 8, in another optional embodiment, before the STA sends a contention access request to the AP in the sending direction according to the received information of the time period, the method further includes:

the STA determines the required transmission time according to the length information of the data to be transmitted; the STA determines that the remaining time of the time period at the current moment is greater than or equal to the transmission time.

For example, the information of the time period includes that the starting time is 2ms, the duration is 3ms, the total length of the time period is 3ms, the length of the data to be sent by the STA is 40 bits, the transmission time required to be spent by the STA is 4ms according to the network transmission speed, and the time period is not enough for the STA to send the data to be sent; or, in another scenario, the information of the time period includes 2ms of start time, the duration is 5ms, then the total length of the time period corresponding to the time domain information is 5ms, the direction corresponding to the time period includes STA1 and STA2, when contention occurs for the first time, STA1 successfully accesses and sends 20 bits of data, and takes 2ms of transmission time, at this time, only 3ms remains in the time period, and 40 bits of data to be sent by STA2 need to take 4ms of transmission time. Even if the AP receives the contention access request sent by the STA2, the AP does not intend that the STA2 performs data uplink and rejects the access request of the STA 2. Therefore, in the embodiment of the invention, before the STA sends the contention access request, the STA determines whether the remaining time of the time period is enough for the STA to send uplink data, if so, the STA sends the contention access request to access the AP, and if not, the STA does not send the contention access request and waits for the next access opportunity, so that the STA sends useless contention access requests and the power consumption of the STA is reduced.

Referring to fig. 9, an embodiment of an access point AP in the embodiment of the present invention includes:

a determining unit 301, configured to determine M directional beam directions of N stations STA that need to perform uplink data transmission relative to the AP;

a dividing unit 302, configured to divide a contention access time period of the AP into X time periods according to the M directional beam directions;

an adjusting unit 303, configured to sequentially adjust the directional beam direction corresponding to each time period according to the X time periods, so as to receive a contention access request sent by at least one STA of the N STAs.

Optionally, the dividing unit 302 is specifically configured to:

and averagely dividing the competition access time of the AP into X time periods according to the M directional beam directions, wherein the X time periods are in one-to-one correspondence with the M directional beam directions.

Optionally, the dividing unit 302 is further specifically configured to:

dividing contention access time of the AP into X time periods on average according to the M directional beam directions, wherein X is integral multiple of M, and each M time periods in the X time periods correspond to the M directional beam directions.

Optionally, the dividing unit 302 is further specifically configured to:

dividing contention access time of the AP into X time periods randomly according to the M directional beam directions, wherein X is greater than or equal to M, and one or more time periods in the X time periods correspond to one direction in the M directional beam directions.

Optionally, the dividing unit 302 is further specifically configured to:

dividing the contention access time of the AP into X time periods according to the M directional beam directions and the number of STAs contained in each directional beam direction, wherein the time period divided by the directional beam direction containing the larger number of STAs is longer, and the X is greater than or equal to the M.

Optionally, the AP further includes:

a sending unit 304, configured to send information of each time period in the X time periods to an STA in a corresponding directional beam direction before the adjusting unit sequentially adjusts the direction of the directional beam corresponding to each time period according to the X time periods, and instruct the STA to send a contention access request to the AP according to the received information of the time periods.

Optionally, the AP further includes:

a sending unit 304, configured to broadcast, to the N STAs, information of each time period in the X time periods and an adjustment sequence of the AP on the M directional beam directions before the adjusting unit sequentially adjusts, according to the X time periods, a directional beam direction corresponding to each time period, and instruct the N STAs to send contention access requests to the AP according to the information of each time period and the adjustment sequence.

For a detailed description of each unit in the embodiment of fig. 9, reference may be made to the detailed description of the method for communication access provided in the embodiment of fig. 3 and the optional embodiment of fig. 3, which is not described herein again.

Referring to fig. 10, an embodiment of a station STA according to the embodiment of the present invention includes:

a determining unit 401, configured to determine a transmission direction of an access point AP with respect to the STA;

a receiving unit 402, configured to receive indication information sent by the AP, where the indication information includes information of a time period of the STA in a contention access time of the AP;

a sending unit 403, configured to send a contention access request to the AP in the sending direction according to the received information of the time period.

Optionally, the indication information includes information of at least two time periods and an adjustment order of at least two directional beam directions by the AP;

the determining unit 401 is further configured to:

determining information of a target time period according to the information of the at least two time periods and the adjustment sequence before the sending unit 403 sends a contention access request to the AP in the sending direction according to the received information of the time periods;

the sending unit 403 is specifically configured to:

and sending a competition access request to the AP in the sending direction according to the information of the target time period.

Optionally, the determining unit 401 is further configured to:

before the sending unit 403 sends a contention access request to the AP in the sending direction according to the received information of the time period, determining a required transmission time according to length information of data to be sent;

the determining unit 401 is further specifically configured to determine that the remaining time of the time period at the current time is greater than or equal to the transmission time.

For a detailed description of each unit in the embodiment of fig. 10, reference may be made to the detailed description of the communication access method provided in the embodiment of fig. 8, which is not described herein again.

The access point AP according to the embodiment of fig. 9 has another form of embodiment, which is shown in fig. 11, and includes: a processor 501, a memory 502, a transceiver 503, wherein the processor 501, the memory 502 and the transceiver 503 are connected by a bus 504, the transceiver 503 may include a transmitter and a receiver, the memory 502 stores computer instructions, and the processor implements the functions of the communication access method in the embodiment of fig. 3 by executing the computer instructions. In addition, the transceiver 503 may implement the corresponding functions of the transmitting unit 304; the processor 501 is configured to execute various types of processing flows, such as: the respective functions of the unit 301, the dividing unit 302 and the adjusting unit 303 may be determined. Various flexible design modes can be adopted for specific implementation, and the corresponding functions of each device can be further referred to the embodiment of the method, which is not limited by the invention.

The station STA according to the embodiment of fig. 9 has another form of embodiment, which is shown in fig. 12 and includes: a processor 601, a memory 602, a transceiver 603, wherein the processor 601, the memory 602 and the transceiver 603 are connected by a bus 604, the transceiver 603 may include a transmitter and a receiver, the memory 602 stores computer instructions, and the processor implements the functions of the communication access method in the embodiment of fig. 8 by executing the computer instructions. In addition, the transceiver 603 may implement the respective functions of the transmitting unit 402 and the transmitting unit 403; the processor 501 is configured to execute various types of processing flows, such as: the corresponding function of unit 401 may be determined. Various flexible design modes can be adopted for specific implementation, and the corresponding functions of each device can be further referred to the embodiment of the method, which is not limited by the invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method of communication access, the method comprising:

an Access Point (AP) determines M directional beam directions of N Stations (STA) needing uplink data transmission relative to the AP, wherein the directional beam directions are directional beam receiving directions, and the directional beam directions are directions in which the AP receives a contention access request sent by the STA and performs data transmission with the STA;

the AP divides a contention access time period of the AP into X time periods according to the M directional beam directions;

the AP sequentially adjusts the direction of the directional wave beam corresponding to each time slot according to the X time slots so as to receive a competition access request sent by at least one STA in the N STAs;

before the AP sequentially adjusts the directional beam direction corresponding to each time segment according to the X time segments, the method further includes:

the AP sends the information of each time slot in the X time slots to the STA in the corresponding directional beam direction, and is used for indicating the STA to send a competition access request to the AP according to the received information of the time slots;

alternatively, the first and second electrodes may be,

and the AP broadcasts the information of each time period in the X time periods and the adjustment sequence of the AP to the directions of the M directional beams to the N STAs, and is used for indicating the N STAs to send competition access requests to the AP according to the information of each time period and the adjustment sequence.

2. The method of claim 1, wherein the AP divides contention access time of the AP into X time periods according to the M directional beam directions, comprising:

3. The method of claim 1, wherein the AP divides contention access time of the AP into X time periods according to the M directional beam directions, comprising:

the AP averagely divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein X is integral multiple of M, and each M time periods in the X time periods correspond to the M directional beam directions.

4. The method of claim 1, wherein the AP divides contention access time of the AP into X time periods according to the M directional beam directions, comprising:

the AP randomly divides the competition access time of the AP into X time periods according to the M directional beam directions, wherein X is larger than or equal to M, and one or more time periods in the X time periods correspond to one direction in the M directional beam directions.

5. The method of claim 1, wherein the AP divides contention access time of the AP into X time periods according to the M directional beam directions, comprising:

and the AP divides the competition access time of the AP into X time periods according to the M directional beam directions and the number of STAs contained in each directional beam direction, wherein the time period divided by the directional beam direction containing more STAs is longer, and the X is greater than or equal to the M.

6. A method of communication access, the method comprising:

a station STA determines the sending direction of an access point AP relative to the STA;

the STA receives indication information sent by the AP, wherein the indication information comprises information of a time period of the STA in the contention access time of the AP;

the STA sends a competition access request to the AP in the sending direction according to the received information of the time period;

the indication information includes information of at least two time periods and an adjustment sequence of the AP to at least two directional beam directions, where the directional beam directions are directional beam receiving directions, and the directional beam directions are directions in which the AP receives a contention access request sent by the STA and performs data transmission with the STA;

before the STA transmits a contention access request to the AP in the transmission direction according to the received information of the time period, the method further includes:

the STA determines the information of a target time period according to the information of the at least two time periods and the adjustment sequence;

the STA sending a contention access request to the AP in the sending direction according to the received information of the time period, including:

the STA sends a competition access request to the AP in the sending direction according to the information of the target time period;

alternatively, the first and second electrodes may be,

the STA determines the required transmission time according to the length information of the data to be transmitted;

the STA determines that the remaining time of the time period at the current moment is greater than or equal to the transmission time.

7. An access point, AP, comprising:

a determining unit, configured to determine M directional beam directions of N stations STA that need to perform uplink data transmission relative to the AP, where the directional beam directions are directional beam receiving directions, and the directional beam directions are directions in which the AP receives a contention access request sent by the STA and performs data transmission with the STA;

a dividing unit, configured to divide a contention access time period of the AP into X time periods according to the M directional beam directions;

an adjusting unit, configured to sequentially adjust the directional beam direction corresponding to each time period according to the X time periods, so as to receive a contention access request sent by at least one STA of the N STAs;

the AP further comprises:

a sending unit, configured to send information of each time period in the X time periods to an STA in a corresponding directional beam direction before the adjusting unit sequentially adjusts the direction of the directional beam corresponding to each time period according to the X time periods, and instruct the STA to send a contention access request to the AP according to the received information of the time periods;

alternatively, the first and second electrodes may be,

a sending unit, configured to broadcast, to the N STAs, information of each time period in the X time periods and an adjustment sequence of the AP on the M directional beam directions before the adjusting unit sequentially adjusts, according to the X time periods, a directional beam direction corresponding to each time period, and instruct the N STAs to send contention access requests to the AP according to the information of each time period and the adjustment sequence.

8. The AP of claim 7, wherein the partitioning unit is specifically configured to:

9. The AP of claim 7, wherein the partitioning unit is further specifically configured to:

10. The AP of claim 7, wherein the partitioning unit is further specifically configured to:

11. The AP of claim 7, wherein the partitioning unit is further specifically configured to:

12. A Station (STA), the STA comprising:

a determining unit, configured to determine a transmission direction of an access point AP with respect to the STA;

a receiving unit, configured to receive indication information sent by the AP, where the indication information includes information of a time period of the STA in a contention access time;

a sending unit, configured to send a contention access request to the AP in the sending direction according to the received information of the time period;

the determination unit is further configured to:

before the sending unit sends a contention access request to the AP in the sending direction according to the received information of the time periods, determining information of a target time period according to the information of the at least two time periods and the adjustment sequence;

the sending unit is specifically configured to:

sending a competition access request to the AP in the sending direction according to the information of the target time period;

the determination unit is further configured to:

before the sending unit sends a contention access request to the AP in the sending direction according to the received information of the time period, determining required transmission time according to length information of data to be sent;

the determining unit is specifically further configured to determine that the remaining time of the time period at the current time is greater than or equal to the transmission time.