A method and system for accessing a wireless channel in a dense environment

Abstract

A method for accessing a wireless channel by a device (112, 113) intending to transmit data, wherein the access to the channel is controlled by a wireless channel controller (111), the method comprising: registering the device (112, 113) as an authorized device with the wireless channel controller (111) at a location; synchronizing (201) a timer of the device (112, 113) indicating a time window; determining (202) a designated time window in which the device (112, 113) can transmit data; performing (203) a clear channel assessment procedure during a preceding time window such that the clear channel assessment ends at the end of a time window preceding the designated time window; and starting transmission (204) of data at the beginning of the designated time window.

Description

Technical Field

[0001] This invention relates to wireless systems, and in particular to controlling wireless channel access, especially for improving channel access in dense environments. Background Technology

[0002] With the increasing popularity of Wi-Fi networks, more and more devices are operating near each other. This often leads to collisions between these devices attempting to use the wireless channel. Collisions degrade the overall effective channel throughput.

[0003] Currently, Radio Local Area Network (RLAN) regulations mandate the implementation of an adaptive channel access mechanism to avoid conflicts in shared wireless frequency bands. Its implementation complies with regulatory standards across all units on the market. Due to the random nature of channel occupancy for each device within range, and the random timing of devices attempting to access the medium, channel utilization is inefficient in dense wireless environments due to numerous transmission (TX) collisions and contention. Co-channel interference occurs, particularly when two or more access point (AP) devices are within TX range, leading to problems with reliable data transmission. This is especially problematic in time-sensitive broadcasting, such as video broadcasting.

[0004] Prior art is known to attempt to avoid collisions. For example, EP3183933 discloses a method for controlling transmission in a communication network, the method comprising: a communication device (AP / STA) detecting potential conflicting use of a transmission resource; the communication device (AP / STA) stopping the potential conflicting use of the transmission resource upon detection; after a backoff period that begins upon detection of the stoppage of use of the transmission resource has expired, the communication device (AP / STA) synchronously performs transmission on the transmission resource with at least one other communication device (AP / STA) for further transmission on the transmission resource; and the communication device (AP / STA) receiving control information to synchronize the transmission with further transmission. Summary of the Invention

[0005] Further development of channel control methods is needed to allow for efficient channel use.

[0006] The present invention provides a method for a device intending to transmit data to access a wireless channel, wherein access to the channel is controlled by a wireless channel controller. The method includes: registering the device as an authorized device at the wireless channel controller; synchronizing a timer for a device-indicated time window; determining a specified time window in which the device can transmit data; performing an idle channel assessment process during a previous time window such that the idle channel assessment ends at the end of a time window preceding the specified time window; and initiating data transmission at the beginning of the specified time window.

[0007] The method may also include transmitting virtual data until the end of the specified time window if the data transmission does not occupy the full length of the specified time window.

[0008] The method may further include, if the time required for data transmission is longer than the length of a specified time window, requesting another device to transmit virtual data during the start of the next specified time window, performing an idle channel assessment process in the previous time window such that the idle channel assessment ends at the end of the time window before the next specified time window, and starting data transmission at the start of the next specified time window.

[0009] Another object of the present invention is a device configured to operate according to the method described herein.

[0010] The present invention also aims to provide a wireless system comprising a wireless channel controller and a plurality of licensed devices configured to operate in accordance with the methods described herein.

[0011] The method of this invention allows for more efficient use of the wireless medium. First, it minimizes the number of wireless collisions between devices. Second, it avoids external interference by controlling the medium to restrict third-party access. Devices using the proposed method comply with regulatory requirements related to adaptability testing, where each transmitted frame should undergo a CAC (Channel Availability Check) before transmission is permitted only when the medium is idle. Therefore, the proposed method can coexist with conventional standardized wireless access mechanisms.

[0012] Symbols and nomenclature

[0013] Some parts of the following detailed description are presented based on data processing procedures, steps, or other symbolic representations of operations on data bits that can be performed on computer memory. Therefore, the computer performs such logical steps, which in turn require physical operations on physical quantities.

[0014] Typically, these quantities take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, and otherwise manipulated in a computer system. For reasons of widespread use, these signals are referred to as bits, packets, messages, values, elements, symbols, characters, terms, numbers, etc.

[0015] Furthermore, all these and similar terms will be associated with appropriate physical quantities and are merely convenient labels applied to those quantities. Terms such as “processing” or “creating” or “transmitting” or “executing” or “determining” or “detecting” or “acquiring” or “selecting” or “calculating” or “generating” refer to the processes and procedures that actuate a computer system, which processes and converts data represented as physical (electronic) quantities in computer registers and memory into other data that are similarly represented as physical quantities in memory or registers or other such information stores.

[0016] Computer-readable (storage) media as referred to in this disclosure can generally be non-transitory and / or include non-transitory devices. In this context, a non-transitory storage medium can include devices that can be tangible, meaning that the device has a concrete physical form, although the device can change its physical state. Thus, for example, non-transitory means that the device remains tangible despite changes in state. Attached Figure Description

[0017] The present invention will be illustrated by way of example embodiments in the accompanying drawings, wherein:

[0018] Figure 1 An example topology of Wi-Fi infrastructure is shown;

[0019] Figure 2 It shows the process of each authorized device accessing the channel within the system.

[0020] Figure 3 This refers to the process by which the wireless channel controller controls channel access.

[0021] Figure 4 The structure of the devices that can operate within the system is shown.

[0022] Figure 5 A first example of communication in a wireless channel with controlled access is shown;

[0023] Figure 6 A second example of communication in a wireless channel with controlled access is shown. Detailed Implementation

[0024] This invention generally relates to Wi-Fi networks as defined by the IEEE 802.11 family of standards. It is also applicable to any other wireless networks that share similar channel access rules, such as Bluetooth, ZigBee, LoRa, Thread, and Z-Wave.

[0025] Figure 1 An example topology for a Wi-Fi infrastructure is shown. The infrastructure includes an authorized (AUTH) environment 110, which includes devices 111-113 authorized to communicate within the system of this invention, and a third-party environment, including third-party (TP) devices 121 not authorized to communicate within the system of this invention. For example, in a hotel facility, the authorized environment 110 may include hotel equipment such as televisions, set-top boxes, access points, repeaters, security devices, sensors, etc., which should have privileged access to the wireless network to facilitate the smooth operation of the hotel facility. For example, the authorized environment 110 may include:

[0026] - The wireless channel controller 111 (AP1) coordinates the remaining licensed devices by synchronizing and managing traffic in the system;

[0027] - At least one wireless system extender 112 (AP2), in addition to the basic function of a range extender, is used to help the wireless controller utilize the spectrum and prevent co-channel interference;

[0028] - At least one system client 113 (STA), which is a client device capable of synchronously transmitting traffic on AP1 or AP2 requests.

[0029] Third-party device 121 is a transmitter that competes with other devices for media access and is considered a source of co-channel interference by authorized system equipment.

[0030] Figure 2 The procedure for channel access for each authorized device within the control system is shown.

[0031] First, in step 200, a device can initialize itself within the wireless transmission system by sending a request to the wireless channel controller 111 (AP1) to be identified as an authorized device. The wireless channel controller 111 (AP1) can be configured to store a list of authorized device identifiers, and other devices can request to be added to that list by sending a specific identifier that authenticates them as authorized devices.

[0032] In step 201, time synchronization is performed among all licensed devices 111-113 within the licensed environment. This can be accomplished, for example, by transmitting a short control signal that does not require an idle channel assessment (CCA) mechanism. To synchronize time, the wireless channel controller 111 (AP1) can send a timestamp generated based on its own clock. The timestamp is included in the data frame transmission, or, if no valid data awaits transmission to the system client, in the control frame. From this point onward, each licensed device 111-113 can only transmit wireless data within the synchronized time window. The time window is defined by the standard as the channel occupancy time value, which is the total time for which a device can transmit without needing to reassess channel availability.

[0033] Next, once the device is time-synchronized, in step 202 it determines a specified time window in which it can transmit data. For example, the device sends a data transmission request to the wireless channel controller 111, requesting an indication of the specified time window number in which it can transmit.

[0034] Next, shortly before the start of the specified time window, in step 203, the CCA procedure is performed according to the requirements of the wireless channel rules. Due to time synchronization between devices, the window time can be precisely determined. During CCA, authorized device transmissions are determined, and devices can begin transmitting immediately after the transmission ends, where the end of the transmission should take effect at the end of the current time window. In step 204, the device begins transmitting its data from the start of the specified time window determined in step 203.

[0035] If the transmission is short, i.e., it takes less than the length of the specified time window, then virtual data (e.g., zero, random numbers, or predefined sequences) is transmitted immediately after the required data transmission is completed in step 205 to fully occupy the specified time window, so that if the third-party device 121 performs the CCA procedure, it will detect that the channel is busy.

[0036] If the transmission is long, i.e., it takes longer than the specified time window, a request is sent in step 206 to ask another authorized device to fill the beginning of the subsequent time window with virtual data (e.g., zero, random numbers, or a predefined sequence), and a CCA procedure is performed in step 207 to comply with regulatory rules requiring CCA before transmission. This request is sent to the wireless channel controller 111, which selects another authorized device, for example, sequentially from a list of authorized devices, to transmit the virtual data. The transmission is scheduled by the wireless controller. During CCA, if virtual data transmission is detected as expected, the device can begin transmitting the remaining data in step 208 immediately after the virtual data transmission ends (where the length of the data is selected so that its transmission covers the time required for a requesting device to perform its CCA procedure, thus, due to time synchronization, the device knows when the channel can be used to resume transmission). Steps 206-208 can be performed whenever all data needs to be transmitted. Because other authorized devices transmit virtual data while the current device performs CCA, if a third-party device 121 performs a CCA procedure, it will detect that the channel is busy.

[0037] Therefore, when the licensed device transmits data, the channel is always busy and inaccessible to the third-party device (i.e., every time the third-party device 121 performs its CCA process, it detects a signal from one of the licensed devices and stops the transmission). Since the licensed devices are time-synchronized, they do not interfere with each other, and the channel bandwidth is used more efficiently because there is no TX interference (or at least interference is significantly reduced).

[0038] The system should always remain synchronized, even if no authorized device is transmitting data, or while waiting for a third-party device to complete its own transmission.

[0039] If the authorized device wants to access the medium asynchronously (e.g., after the third-party device releases the medium), the transmission stops before the start of the next synchronization cycle and a new frame transmission begins synchronously.

[0040] Figure 3 The process of channel access controlled by a wireless channel controller is illustrated. It performs two main actions: monitoring the wireless channel (310) for requests from other devices and performing periodic activities (320). Upon receiving a channel access request from another device in step 311, the wireless channel controller checks whether the device is authorized (e.g., if the device has an authorization number or a specific identifier that has been sent in the request); if so, it adds the device to the list of authorized devices. Upon receiving a transmission request from an authorized device in step 312, the wireless channel controller adds the device to a transmission queue, which is then used in step 322. If an authorized device intends to transmit a large amount of data, it can indicate the number of time windows required for data transmission, or send a separate request for each time window required for transmission. The transmission queue can be arranged in the order in which requests are received or in the order of the authorized devices or the data to be transmitted (i.e., when requesting access to a time window, the authorized device can indicate the priority level of the data to be transmitted). Upon receiving a virtual data request from an authorized device in step 313, the wireless channel controller sends a request to another device to initiate the transmission of virtual data at the start of the next time window. Alternatively, the system can be configured such that the licensed device does not send a virtual data request in step 206, but the wireless channel controller itself can recognize that the licensed device will need to generate a CCA at the start of the time window and request another device to perform virtual data transmission without the specific request in step 206. As a periodic task, in step 321, the wireless channel controller sends timestamps to all licensed devices to synchronize time. Furthermore, in step 322, the wireless channel controller sends information to the licensed devices about the next time window in which they can transmit their data, so that... Figure 2 The information is received in step 203 of the process.

[0041] Figure 4The structure of a wireless channel controller 111, extender 112, or client 113 device that can operate within a system is illustrated. Device 400 may include at least one non-transitory processor-readable storage medium 410 storing at least one of processor-executable instructions 415 or data 416; at least one processor 420 is communicatively coupled to at least one non-transitory processor-readable storage medium 410. Data 416 may include a list of authorized devices in the system (stored at the wireless channel controller and / or other devices) and configuration parameters, such as timing synchronization data and time window parameters (e.g., time window length). A wireless network communication interface 430 is used to access a wireless channel. At least one processor 420 is configured to (by executing instructions 415 and reading data 416) execute... Figure 2 and Figure 3 The method.

[0042] Figure 5 A first example of communication in a wireless channel with controlled access is shown. Initially (511), the wireless channel controller 111 (AP1) synchronizes its time with all authorized devices in the system. Next, the wireless channel controller AP1 performs a CCA procedure (512) before the time window T1 in which it intends to transmit data, and after successfully checking that the channel is not occupied by other devices, it transmits data during the time window T1 (513). Meanwhile, authorized AP2 has requested access to the channel, so AP1 sends AP2 information that AP2 can transmit in the time window T2. Therefore, shortly before the start of T2, AP2 performs a CCA procedure (521), and after successfully checking that the channel is not occupied by any device other than AP1 (it is known that transmission is completed at the end of T1), AP2 begins transmitting data at the beginning of the time window T2 (522). After the main payload of the data (522) has finished, AP2 begins transmitting virtual data (523) to fill the entire time window T2 to prevent other devices from accessing it. Then, data is transmitted in a similar manner in time window T3 by AP1 (515), time window T4 by authorized STAs (532, 533), time window T5 by AP1 (517), time window T6 by AP1 (519), and time window T7 by authorized STAs (535, 536), with a CCA (514, 531, 516, 518, 534) preceding each transmission. When AP1 performs CCA (518) at the beginning of time window T6, AP2 is instructed to transmit dummy data (525, preceded by CCA 524) during this check to prevent the channel from being taken over by any third-party device, so that when a third-party STA performs CCA (547), the channel is busy. Therefore, whenever a third-party STA performs CCA (541-547), the channel is busy, and the third-party STA cannot transmit.

[0043] Figure 6 A second example of communication in a wireless channel with controlled access is shown. Initially (611), the wireless channel controller 111 (AP1) synchronizes its time with all licensed devices in the system. The channel is occupied by transmissions from third-party STAs (previously CCAs 642 and 644 of 643). Therefore, when AP1 performs the first CCA (612), it detects that the channel is occupied. AP1 continues the CCA process (613-615) until it detects that the channel is not occupied, and then it begins transmitting virtual data (616) until the end of the time window. Next, if AP1 intends to transmit data, it requests AP2 to occupy the channel at the beginning of the next time window T4 (previously CCA 622 of 621), while AP1 performs the CCA process (617) before transmitting data (618). Since the channel is now reserved for the system, licensed devices can subsequently transmit in time windows T5 (624-625) and T6 (632-633) where CCAs (623, 631) previously occurred. As long as the authorized device transmits, the third-party STA will see the channel occupied during its CCA process (645-647). The third-party STA can only transmit after the authorized device stops occupying the channel (previously CCA 648, 649).

[0044] Although the invention of this disclosure has been depicted, described, and defined with reference to specific preferred embodiments, these references and exemplary embodiments in the foregoing specification do not imply any limitation on the invention. However, it will be apparent that various modifications and changes can be made thereto without departing from the broader scope of the technical concept. The presented preferred embodiments are merely exemplary and are not an exhaustive list of the scope of the technical concept presented in this disclosure.

[0045] Therefore, the scope of protection is not limited to the preferred embodiments described in the specification, but is limited only by the appended claims.

Claims

1. A method for accessing a wireless channel by a device (112, 113) intending to transmit data, wherein, Access to the channel is controlled by a wireless channel controller (111), characterized in that the method comprises: registering (200) the device (112, 113) as an authorized device at the wireless channel controller (111); synchronizing (201) a timer of the device (112, 113) indicating time windows; determining (202) a designated time window in which the device (112, 113) can transmit data; performing (203) a clear channel assessment procedure during a preceding time window, such that the clear channel assessment ends at the end of a time window preceding the designated time window; and starting transmission (204) of data at the start of the designated time window; the method further comprises, in case the transmission (204) of data requires more time than the length of the designated time window, requesting (206) another device to transmit dummy data during the start of a next designated time window, performing (207) a clear channel assessment procedure during a preceding time window, such that the clear channel assessment ends at the end of a time window preceding the next designated time window, and starting transmission (208) of data at the start of the next designated time window.

2. The method of claim 1, wherein, further comprising, in case the transmission (204) of data does not occupy the full length of the designated time window, transmitting (205) dummy data until the end of the designated time window.

3. A device (112, 113) for transmitting data, comprising a controller configured to operate according to the method of claim 1 or 2.

4. A wireless system, characterized by the wireless system comprises a wireless channel controller (111) and a plurality of authorized devices configured to operate according to the method of claim 1 or 2.

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