Spatial multiplexing device and method in wireless network environment

Abstract

The present disclosure provides for setting a Clear Channel Assessment (CCA) threshold according to a simultaneous transmission power adjustment by calculating a simultaneous transmission power based on a density of a peripheral access point, the simultaneous transmission power being a power for simultaneous transmission of signals with an occupying transmission node that is occupying a channel to transmit signals at a reference transmission power, and providing a Clear Channel Assessment (CCA) threshold based on the simultaneous transmission power adjustment. According to the spatial multiplexing device and method, whether the signals are transmitted at the same time or not is judged according to an idle channel evaluation threshold value and the strength of the signals transmitted from occupied transmission nodes, and the space can be effectively multiplexed.

Description

Technical Field

[0001] The present disclosure relates to a spatial multiplexing device and method in a wireless network environment. Background Art

[0002] In wireless networks, IEEE 802.11 wireless local area network (WLAN) is developing the IEEE 802.11be (Wi-Fi 7) standard, following the release of IEEE 802.11ax (Wi-Fi 6) in May 2021. To ensure a high level of service quality, the IEEE 802.11be (Wi-Fi 7) standard aims to achieve a transmission speed of more than 30Gbps, and plans to add functions such as 4096QAM and multi-radio units (Multi-RU). The IEEE 802.11be (Wi-Fi 7) standard is planned to be released in 2024, and the IEEE 802.11bn (Wi-Fi 8) standard will be developed thereafter.

[0003] In order to occupy the channel, the IEEE 802.11 WLAN network uses the distributed coordination function (DCF) of the Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) method. Therefore, before the DCF transmission, based on the Clear Channel Assessment (CCA) threshold, if the measured energy intensity (or power intensity) is less than the CCA threshold, the channel is judged to be in an idle state and transmission is performed. On the contrary, if the measured energy intensity is greater than the CCA threshold, the channel is judged to be in use and transmission is suspended. However, since the parameters used in the existing DCF method are conservatively set, there is a limitation that the space cannot be effectively utilized in an environment with dense terminals.

[0004] In order to effectively utilize space, the IEEE 802.11be (Wi-Fi 7) network plans to introduce Coordinated Spatial Reuse (CSR) technology in the standard. This technology determines the transmission power through adjustments between access points (APs). CSR technology adjusts the transmission power through adjustments between access points (APs) to improve spatial transmission performance, but it has the disadvantage of increasing system overhead due to the exchange of control frames, link information, and transmission power.

[0005] Spatial multiplexing technology was included in the standard for the first time in the IEEE 802.11ax (Wi-Fi 6) network, but the spatial multiplexing technology included in the IEEE802.11ax (Wi-Fi 6) network is a spatial multiplexing technology based on OBSS_PD (Overlapping Basic Service Set Packet Duplication). It does not consider any optimization or performance, but simply provides boundary values ​​(-62dBm to -82dBm) for adjusting the OBSS level regarding the CCA threshold, and adjusts the OBSS level within the boundary value range, thereby working in a manner of adjusting the transmission power, so the performance is reduced.

[0006] On the other hand, as the Internet of Things (IoT) is widely used in daily products, the number of nodes using the IEEE 802.11 WLAN protocol is growing exponentially, and space must be used effectively to ensure the performance of these nodes. Therefore, in order to effectively use space, it should be possible to determine the transmission power by considering interference or transmission success rate even when a small number of frames are exchanged. Summary of the invention

[0007] Technical issues

[0008] The present disclosure aims to provide a spatial multiplexing device and method for adjusting transmission power according to the density of peripheral access points so as to maximize the success rate of existing transmission and simultaneous transmission.

[0009] Another object of the present disclosure is to provide a spatial multiplexing apparatus and method for adaptively adjusting a CCA threshold according to a determined transmission power so that space can be effectively multiplexed.

[0010] The purpose of the present disclosure is to provide a spatial multiplexing device and method that can suppress the increase of system overhead through a small amount of frame exchange and improve performance through spatial multiplexing.

[0011] Technical Solution

[0012] According to one embodiment of the present disclosure, a spatial multiplexing device is a device including a memory and a processor that executes at least a part of the operations according to the program stored in the memory and is included in a transmission node of a wireless network, wherein the processor is used to: calculate a simultaneous transmission power for transmitting signals simultaneously with an occupied transmission node that is transmitting signals at a reference transmission power on an occupied channel based on the density of peripheral access points; adjust and set a Clear Channel Assessment (CCA) threshold according to the simultaneous transmission power; and determine whether to transmit simultaneously based on the CCA threshold and the strength of the signal transmitted from the occupied transmission node.

[0013] The processor may calculate and obtain a simultaneous transmission power that maximizes the product of the transmission success probability of the occupied transmission node and the simultaneous transmission success probability, which is the transmission success probability during simultaneous transmission.

[0014] When the simultaneous transmission power is not included in the standard transmission power range, the processor may cause the transmitting node to postpone transmission so as not to perform simultaneous transmission.

[0015] When the strength of the signal transmitted from the occupied transmission node is below a CCA threshold, the processor may cause the transmission node to perform simultaneous transmission.

[0016] In a case where the occupied transmission node is a node constituting an internal BSS of the same Basic Service Set (BSS), the processor may set the reference CCA threshold as the CCA threshold.

[0017] In a case where the occupied transmission node is a node of an external BSS constituting other BSSs, the processor may set the CCA threshold so that the sum of the simultaneous transmission power and the minimum CCA threshold is equal to the sum of the reference transmission power and the CCA threshold.

[0018] The processor may confirm the density of peripheral access points based on BSS information obtained through periodic exchange between access points.

[0019] The processor may determine whether the occupied transmission node is a node of an internal BSS included in the same BSS or a node of an external BSS included in another BSS based on BSS color information included in BSS information obtained through periodic exchange between access points.

[0020] The transmission node may be implemented by a device that occupies a channel using a distributed coordination function (DCF) in a carrier sense multiple access / collision avoidance (CSMA / CA) method based on IEEE 802.11.

[0021] According to another embodiment of the present disclosure, a spatial multiplexing method is executed by a processor of a transmission node included in a wireless network, including: a step of calculating a simultaneous transmission power for transmitting signals simultaneously with an occupied transmission node that is transmitting signals at a reference transmission power on an occupied channel based on the density of peripheral access points; a step of adjusting and setting a Clear Channel Assessment (CCA) threshold according to the simultaneous transmission power; and a step of determining whether to transmit simultaneously based on the CCA threshold and the strength of a signal transmitted from the occupied transmission node.

[0022] Technical Effects

[0023] The spatial multiplexing device and method disclosed in the present invention adjust the transmission power based on the density of peripheral access points, thereby suppressing the increase of additional system overhead through a small amount of frame exchange while maximizing the success rate of existing transmission and simultaneous transmission, and adaptively adjusting the CCA threshold according to the determined transmission power to enable effective space multiplexing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A diagram for explaining the concept of a spatial multiplexing method of a wireless network system according to an embodiment;

[0025] Figure 2 is a schematic structural diagram of a spatial multiplexing device according to an embodiment of the present invention;

[0026] Figure 3 An example of a frame header for using a spatial multiplexing technique based on OBSS PD according to an embodiment is shown;

[0027] Figure 4 A spatial multiplexing method for a wireless network system according to an embodiment is shown;

[0028] Figure 5 A diagram for illustrating a computing environment including a computing device according to one embodiment. DETAILED DESCRIPTION

[0029] The following describes the specific implementation of the embodiments of the present disclosure with reference to the accompanying drawings. The following detailed description is provided to help fully understand the methods, devices and / or systems described in this specification, but this is only an example and the present invention is not limited thereto.

[0030] When describing the embodiments of the present disclosure, when it is judged that the specific description of the known technology related to the present invention may obscure the gist of the embodiments, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of the functions of the present invention, which may vary according to the intentions or conventions of the user or operator. Therefore, the definition should be determined according to the overall content of this specification. The terms used in the detailed description are only used to illustrate an embodiment and shall not be used for limitation. The singular form of expression also includes the plural form of expression when there is no clear other use in the text. In this description, the terms such as "including" or "having" are intended to indicate specific characteristics, numbers, steps, actions, elements, a part of them or a combination, and should not be interpreted as excluding the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, a part of them or a combination other than those described. In addition, the terms such as "... part", "... device", "module", "block" described in the specification refer to a unit that processes at least one function or action, which can be implemented by hardware, software or a combination of hardware and software.

[0031] Figure 1 1 is a diagram for explaining the concept of a spatial multiplexing method of a wireless network system according to an embodiment. Figure 1 The wireless network system may be, for example, an IEEE 802.11 WLAN system.

[0032] refer to Figure 1 , a wireless network system can be constructed in units of a basic service set (BSS), each BSS includes access points AP1, AP2, and can also include stations STA1, STA2 that access the network through access points AP1, AP2 included in the BSS. That is, access points AP1, AP2 can provide communication services for stations STA1, STA2 included in the same BSS. Here, as a simple example, the first BSS and the second BSS each include only one access point AP1, AP2 and one station STA1, STA2, but each BSS may include multiple access points and multiple stations.

[0033] Access points AP1, AP2 and stations STA1, STA2 are devices that can communicate using the IEEE 802.11-based medium access control (MAC) protocol. Access points AP1, AP2 can also be called routers, gateways, and stations STA1, STA2 can also be called subscribers, terminals, and user equipment. Stations STA1, STA2 can be implemented by mobile devices such as smartphones, personal computers, smart TVs, and other devices.

[0034] exist Figure 1 In the example, the first access point AP1 can form the first BSS to provide communication services for the first station STA1, and the second access point AP2 can form the second BSS to provide communication services for the second station STA2. BSS is not a physical service area, but a logical structure. Therefore, the size of the BSS area where each access point AP1, AP2 communicates with the stations STA1, STA2 included in the same BSS can be adjusted in various ways according to the communication environment. In addition, Figure 1 As shown, different BSSs may overlap with each other to generate Overlapping Basic Service Sets (OBSS).

[0035] In a network environment where OBSS is generated, if the transmission nodes of different BSSs (i.e., access points AP1, AP2 and stations STA1, STA2) perform communication at the same time, mutual interference may occur. For example, when the first access point AP1 of the first BSS sends a signal to the first station STA1, a collision may occur when the second access point AP2 simultaneously sends a signal to the second station STA2.

[0036] To occupy the channel, the IEEE 802.11 WLAN network uses a distributed coordination function (DCF) in the carrier sense multiple access / collision avoidance (CSMA / CA) mode. Therefore, while the transmission node of the first BSS is sending a signal, the transmission node of the second BSS should not send a signal and postpone the transmission, and then reoccupy the channel through competition and send a signal. In this case, the performance of the wireless network, that is, the transmission efficiency, is reduced.

[0037] exist Figure 1 In the example shown in (a), the transmission range of the first access point AP1 to the first station STA1 does not include the second access point AP2 and the second station STA2. Similarly, the transmission range of the second access point AP2 to the second station STA2 does not include the first access point AP1 and the first station STA1. Therefore, if other factors are not considered and only the transmission range is considered, if the first AP1 and the second access point AP2 are as follows Figure 1(b) appropriately adjusts the transmission power to reduce the size of the area where the transmission range overlaps, so that while the first access point AP1 is sending a signal to the first station STA1, the second access point AP2 can simultaneously transmit a signal to the second station STA2. The technology of adjusting the transmission power of access points AP1 and AP2 of different BSSs as above to enable simultaneous signal transmission is called spatial reuse technology.

[0038] But in existing wireless networks, such as Figure 1 As shown, if the second access point AP2 wants to transmit a signal to the second station STA2 while the first access point AP1 is transmitting a signal to the first station STA1, the second access point AP2 will use the OBSS_PD technology introduced in the IEEE802.11ax (Wi-Fi 6) regardless of the transmission power, and confirm the CCA range (CCA range) as the judgment basis for the interference range (Interference range) based on the set CCA threshold.

[0039] In addition, if Figure 1 As shown in (a), if it is determined that the confirmed CCA range (CCA range) includes other access points (here, the first access point AP1), the second access point AP2 cannot transmit signals to the second station STA2 regardless of whether the transmission power is adjusted. This is because the CCA range (CCA range) of the second access point AP2 includes the first access point AP1, so it is determined that the second access point AP2 transmitting signals to the second station STA2 will interfere with the communication between the first access point AP1 and the first station SAT1.

[0040] However, in existing wireless networks, the CCA threshold is set to a fixed value and is judged with an extremely wide CCA range (CCArange). Although IEEE 802.11ax (Wi-Fi 6) stipulates that the CCA threshold can be adjusted within the range of -62dBm to -82dBm, it does not provide CCA threshold adjustment rules. In addition, existing wireless networks consider the interference range from a very conservative point of view and set the CCA threshold to a fixed value of -82dBm. In other words, the CCA range (CCArange) is interpreted as wide as possible.

[0041] Therefore, if Figure 1 As shown in (b), even if the second access point AP2 adjusts the transmission power so that the transmission range does not overlap with the transmission range of the first access point AP1, if the second access point AP2 Figure 1If the CCA range is interpreted as broadly as in (a) to determine whether transmission is possible, the second access point AP2 will not be able to transmit signals to the second station STA2 during the period when the first access point AP1 transmits signals. That is, the wireless network efficiency will be low.

[0042] To solve such problems, the present disclosure provides a rule for adjusting the CCA threshold within the range of -62dBm to -82dBm according to the provisions of IEEE 802.11ax (Wi-Fi 6). That is, the CCA threshold can be adaptively adjusted within the range specified by IEEE 802.11ax (Wi-Fi 6).

[0043] If the CCA threshold is adaptively changed to adjust the CCA range (CCA range) as the interference discrimination reference to Figure 1 As shown in (b), the second access point AP2 can also transmit signals to the second station STA2 by adjusting the transmission power during the period when the first access point AP1 transmits signals. Therefore, the efficiency of the wireless network can be improved. Here, the first access point AP1 can also change the CCA threshold independently from the second access point AP2 to adjust the interference range. In addition, since the adjusted interference range does not include other access points (here, the second access point AP2), the first access point AP1 can transmit signals to the first station STA1 regardless of whether the second access point AP2 communicates.

[0044] As described above, in the present disclosure, the access points AP1 and AP2 of the BSS change the CCA range by adjusting the CCA threshold.

[0045] To this end, in the present disclosure, the access points AP1 and AP2 of each BSS first confirm the density λ of the peripheral access points AP. And according to the confirmed density λ, the transmission power that can improve the transmission success rate even when transmitting simultaneously is determined taking into account the influence of mutual interference. Here, each access point AP1 and AP2 can independently determine the transmission power without further exchanging additional control frames or link information and transmission power for mutual adjustment. That is, each access point AP1 and AP2 determines the transmission power and CCA threshold in a non-coordination manner, so that the system overhead incurred for adjustment is minimized.

[0046] In addition, each access point AP1, AP2 adaptively adjusts and determines the CCA threshold according to the determined transmission power. When the transmission power and the CCA threshold are adaptively adjusted, as shown in FIG. Figure 1 As shown in (b), the transmission range and the CCA range do not include the transmission paths between the access points AP1, AP2 and the stations STA1, STA2 of different BSSs, so the transmission nodes of different BSSs can transmit signals at the same time.

[0047] Figure 2 This is a diagram briefly illustrating the configuration of a spatial multiplexing device according to one embodiment, differentiated according to the operations to be performed. Figure 3 An example of a frame header for using the OBSS PD-based spatial multiplexing technique according to one embodiment is shown.

[0048] In the present disclosure, the spatial multiplexing device may be included in the access points AP1 and AP2. As an example, when the first access point AP1 occupies the channel, the second access point AP2 attempts to transmit simultaneously, so the spatial multiplexing device included in the second access point AP2 is described. Figure 1 As shown, the first access point AP1 is transmitting frames to the first station STA1, and the spatial multiplexing device of the second access point AP2 determines whether to transmit frames to the second station STA2, the transmission power and the CCA threshold during the period when the first access point AP1 transmits frames to the first station STA1.

[0049] Specifically, the spatial multiplexing device according to the present disclosure may include a receiving module 21, a transmission adjustment module 22 and a sending module 27. Figure 2 shown.

[0050] The receiving module 21 receives a signal (or frame) transmitted from a server (not shown) or a peripheral access point (here, AP1) or a station STA1 included in the same BSS. At this time, the receiving module 21 can measure the strength of the transmitted signal and transmit it to the transmission adjustment module 22.

[0051] In addition, the receiving module 21 can transmit the BSS information in the signal periodically transmitted from the peripheral access point AP1 to the transmission adjustment module 22. Here, as an example, the BSS information can be transmitted in the form of a beacon frame, which can include whether to use spatial multiplexing technology and the transmission power of the peripheral BSS, that is, the reference transmission power P N , reference transmission power P N is the transmission power of the access point or station as a transmission node of the peripheral BSS. Figure 3 As shown, in the BSS information, BSS color information 32 that can identify the BSS of the device that transmitted the signal can be included in the SIG-A field 31 of the frame header for transmission.

[0052] The transmission adjustment module 22 analyzes the density λ of the peripheral access point AP1, and determines the simultaneous transmission power P for simultaneous transmission during the transmission of the peripheral access point AP2 in the spatial multiplexing manner according to the analyzed density λ. C . And according to the determined simultaneous transmission power PC A CCA threshold is determined, and whether to transmit a frame to the second station STA2 is determined based on the determined CCA threshold.

[0053] The transmission adjustment module 22 may include a state analysis module 23, a transmission power adjustment module 24, a CCA adjustment module 25 and a transmission determination module 26. The state analysis module 23 first analyzes the BSS information transmitted from the peripheral access point AP1 to confirm the density λ of the peripheral access point AP1.

[0054] The transmission power adjustment module 24 calculates the simultaneous transmission power P for simultaneous transmission with the peripheral access point AP1 according to the spatial multiplexing technology based on the density λ of the peripheral access point AP1 confirmed by the state analysis module 23. C At this time, the transmission power adjustment module 24 calculates the simultaneous transmission power P C , so that the transmission success probability of itself and the occupied transmission nodes of the peripheral BSS that are transmitting signals on the occupied channel is maximized.

[0055] When simultaneous transmission is performed during the transmission of an occupied transmission node (here, the first access point AP1 as an example), the transmission success probability can be calculated by mathematical formula 1:

[0056]

Mathematical formula 1

[0057]

[0058] Among them, α is the path loss parameter, γ th is the SINR threshold used to ensure successful transmission. N is the reference transmission power P of the occupied transmission node in the peripheral BSS that is transmitting signals N In addition, P th is the RSSI (Received Signal Strength Indicator) threshold used to ensure successful transmission, and sinc(·) represents the synchronization function.

[0059] In addition, when performing simultaneous transmission, the transmission success probability of the occupied transmission node in the peripheral BSS that is transmitting the signal can be calculated by mathematical formula 2:

[0060]

Mathematical formula 2

[0061]

[0062] In order to calculate the transmission success probability of the occupied transmission node of the own and peripheral BSS calculated according to Mathematical Formulas 1 and 2 To achieve the maximum simultaneous transmission power P C , we can construct the objective function as shown in Mathematical Formula 3

[0063]

Mathematical formula 3

[0064]

[0065] Therefore, the transmission power adjustment module 24 can solve the objective function of Mathematical Formula 3 by Achieve the maximum optimization problem to obtain the simultaneous transmission power P C .

[0066] But the objective function of mathematical formula 3 The maximum optimization problem should be to transmit power P at the same time C The value is greater than 0 and less than the reference transmission power P N As an example, taking the 20MHz frequency band as the reference, the reference transmission power P N It can be 21dBm.

[0067] The transmission power adjustment module 24 can continuously iterate and update the objective function of the mathematical formula 3 The optimization problem is solved until the value calculated by the gradient descent method (Gradient Descent) as shown in Mathematical Formula 4 converges, thereby obtaining the optimized simultaneous transmission power P C .

[0068]

Mathematical formula 4

[0069]

[0070] Here η is the learning rate.

[0071] The transmission power adjustment module 24 calculates the simultaneous transmission power P C After that, the CCA adjustment module 25 calculates the simultaneous transmission power P C Calculate the adjusted CCA threshold τ PD The CCA adjustment module 25 can adjust the CCA threshold τ according to equation 5. PD .

[0072]

Mathematical formula 5

[0073]

[0074] in, is the minimum CCA threshold specified in the IEEE 802.11 standard (as an example, -62dBm).

[0075] According to Mathematical Formula 5, the simultaneous transmission power P C Adjustment of CCA threshold τ PD Set to the calculated simultaneous transmission power P C With the minimum CCA threshold The sum is equal to the reference transmission power P N With the adjusted CCA threshold τ PD sum.

[0076] As described above, the most conservative value -82 dBm is generally used as the CCA threshold, so that simultaneous transmission is not performed even if interference of a degree that allows spatial reuse occurs.

[0077] In the present disclosure, the simultaneous transmission power P is calculated C Then according to the calculated simultaneous transmission power P C Adaptively adjust the CCA threshold τ PD , received according to the adjusted CCA threshold τ PD Perform simultaneous transmissions, allowing for more aggressive use of spatial multiplexing techniques.

[0078] The transmission determination module 26 first determines the simultaneous transmission power P calculated by the transmission power adjustment module 24. C Is it within the standard transmission power range of 1dBm to 21dBm specified by the IEEE 802.11 protocol standard? C If it is not included in the standard transmission power range, the transmission will be postponed.

[0079] On the contrary, if the judgment result is that the transmission power P C If the transmission power is within the standard transmission power range, the transmission determination module 26 determines whether the occupied transmission node is an internal BSS or an external BSS based on the BSS information periodically transmitted by the access point AP1 currently occupying the channel. The internal BSS or the external BSS can be determined by comparing the BSS color of the BSS color field 33 of the BSS color information field 32 in the frame header transmitted from the access point AP1 with its own BSS color.

[0080] If the determination result is internal BSS, the transmission determination module 26 sets the reference CCA threshold τ ref As mentioned above, in the past, the CCA threshold was generally set most strictly from a conservative perspective. Therefore, as an example, when the channel bandwidth is 20Mhz, the benchmark CCA threshold τ ref It can be -82dBm. If the judgment result is external BSS, then according to the simultaneous transmission power P C Adjust the CCA threshold τ PDis set as the CCA threshold, and determines whether to transmit according to the set CCA threshold. That is, the transmission determination module 26 sets the reference CCA threshold τ to the value of the transmission node according to whether the occupied transmission node of the occupied channel is an internal BSS or an external BSS. ref Or adjust the CCA threshold τ PD The CCA threshold is set to determine transmission, and whether to transmit is determined based on the set CCA threshold.

[0081] At this time, the transmission determination module 26 determines whether the received signal strength measured from the signal from the occupied transmission node is greater than the set CCA threshold. If the received signal strength is greater than the CCA threshold, it is determined that the channel is in use and the transmission is postponed. If the received signal strength is below the CCA threshold, it is determined that the channel is idle, and the transmission module 27 transmits at the calculated simultaneous transmission power P C Transmit a signal (or frame) to the second station STA2.

[0082] As a result, the spatial multiplexing device of the present disclosure adaptively sets the simultaneous transmission power P according to the density of the peripheral access point AP1. C and CCA threshold, according to the set simultaneous transmission power P C The CCA threshold determines whether to transmit simultaneously and performs simultaneous transmission. Therefore, the simultaneous transmission power P C and CCA thresholds are adaptively adjusted, thereby improving system performance by enabling very effective use of spatial multiplexing technology. In addition, since each access point independently calculates and sets the simultaneous transmission power P based on the BSS information periodically transmitted from the peripheral access points, C and CCA threshold, so the amount of information that needs to be exchanged for simultaneous transmission is small, thereby reducing system overhead.

[0083] In the illustrated embodiment, each component may have different functions and capabilities in addition to those described below, and may include additional components in addition to those described below. In addition, in one embodiment, each component may be implemented by one or more physically distinguished devices, or may be implemented by one or more processors or a combination of one or more processors and software, and may be different from the illustrated example and not clearly distinguished in specific operations.

[0084] and, Figure 2The spatial multiplexing device shown can be implemented in a logic circuit by hardware, firmware, software or a combination thereof, or can be implemented by a general or special computer. The device can be implemented by a hardwired device, a field programmable gate array (FPGA), a custom semiconductor (Application Specific Integrated Circuit, ASIC), etc. In addition, the device can be implemented by a system on chip (SoC) including one or more processors and controllers.

[0085] Furthermore, the spatial multiplexing device can be mounted on a computing device or server having hardware elements in the form of a combination of software, hardware, or both. The computing device or server may refer to a variety of devices including a communication device such as a communication modem for communicating with various devices or wireless / wireless communication networks, a memory for storing data for running programs, and a microprocessor for running programs to perform calculations and commands.

[0086] Figure 4 A spatial multiplexing method of a wireless network system according to an embodiment is shown. It is also assumed here that the spatial multiplexing method is performed by access points AP1 and AP2 for illustration, but the invention is not limited thereto.

[0087] refer to Figures 1 to 3 According to the spatial multiplexing method disclosed in the present invention, first, multiple access points AP1 and AP2 of the wireless network periodically exchange BSS information with each other to obtain BSS information about peripheral access points (51). Then, the density λ of the peripheral access points is confirmed based on the obtained BSS information of the peripheral access points (52). At the same time, the BSS color information of the BSS information is confirmed to determine whether it is an access point of an internal BSS with the same BSS color as itself or an access point of an external BSS with a different BSS color.

[0088] Furthermore, each access point AP1, AP2 determines whether there is a frame to be transmitted to the stations STA1, STA2 in the same BSS (53). Here, the frame to be transmitted may be a frame transmitted from a server (not shown) or other access points or stations.

[0089] When the result of the determination is that there is a frame to be transmitted, a backoff process is performed by the DCF of the CSMA / CA method to try to occupy the channel (54). For example, the access points AP1 and AP2 can try to occupy the channel by transmitting a request to send (RTS) frame. And, it is determined whether the channel occupation is successful (55). If the channel is successfully occupied, the frame to be transmitted is transmitted through the occupied channel (62). If the channel occupation fails, the simultaneous transmission power P is calculated based on the density λ of the confirmed peripheral access points. C (56) At this point, the probability of successful transmission of the access point that has occupied the channel can be calculated The probability of successful simultaneous transmission when performing simultaneous transmission with itself The maximum power of the product is taken as the simultaneous transmission power P C As an example, the simultaneous transmission power P can be calculated using the gradient descent method C .

[0090] Then determine the calculated simultaneous transmission power P C Is it within the standard transmission power range (1dBm to 21dBm) specified by the IEEE 802.11 protocol standard (57). If the calculated simultaneous transmission power P C If the transmission power exceeds the standard transmission power range, the network allocation vector (NAV) timer is set and the transmission is postponed (61). C If the transmission power is within the standard transmission power range, it is determined whether the currently occupied transmission node of the channel is a transmission node of the internal BSS or a transmission node of the external BSS. If it is a transmission node of the internal BSS, the reference CCA threshold τ is increased as before. ref Set as the CCA threshold, and if it is a transmitting node of an external BSS, calculate according to the simultaneous transmission power P C Adjusted CCA threshold τ PD , set it as the CCA threshold (58). At this time, the CCA threshold τ can be adjusted PD , so that the simultaneous transmission power P C With the minimum CCA threshold The sum is equal to the reference transmission power P which is the transmission power of the transmission node occupying the channel. N With the adjusted CCA threshold τ PD The sum of the reference transmission power P N May be included in BSS information obtained from peripheral access points.

[0091] After the CCA threshold is set, the strength of the signal transmitted from the transmission node that is occupying the channel is measured (59), and then it is determined whether the strength of the measured signal exceeds the set CCA threshold (60). If the strength of the measured signal exceeds the set CCA threshold, the transmission is postponed (61). If the strength of the measured signal is below the set CCA threshold, the frame is also transmitted to the station while the occupied transmission node occupies the channel for transmission (62).

[0092] Figure 4 The various processes are described in sequence, but this is only an exemplary description. Those skilled in the art can make various modifications and variations within the scope of the essential characteristics of the embodiments of the present invention, such as changing Figure 4 The steps may be performed in the order in which they are described, or more than one step may be performed in parallel, or other steps may be added.

[0093] Figure 5 is a diagram for illustrating a computing environment including a computing device according to one embodiment.

[0094] In the illustrated embodiment, each component may have different functions and capabilities in addition to those described below, and may include additional components in addition to those described below. The illustrated computing environment 70 includes a computing device 71 that can execute Figure 4 In one embodiment, the computing device 71 may be Figure 2 The spatial multiplexing device shown includes more than one component.

[0095] The computing device 71 includes at least one processor 72, a computer-readable storage medium 73, and a communication bus 75. The processor 72 can cause the computing device 71 to operate according to the above-described exemplary embodiments. For example, the processor 72 can run one or more programs 74 stored in the computer-readable storage medium 73. The one or more programs 74 may include one or more computer-executable instructions, which may be configured to cause the computing device 71 to perform operations according to the exemplary embodiments when executed by the processor 72.

[0096] The communication bus 75 interconnects various other components of the computing device 71 including the processor 72 and the computer-readable storage medium 73 .

[0097] The computing device 71 may further include one or more input / output interfaces 76 and one or more communication interfaces 77 that provide interfaces for one or more input / output devices 78. The input / output interfaces 76 and the communication interfaces 77 are connected to the communication bus 75. The input / output devices 78 may be connected to other components of the computing device 71 through the input / output interfaces 76. Exemplary input / output devices 78 may include: a pointing device (mouse or tracking pad, etc.), a keyboard, a touch input device (touch pad or touch screen, etc.), a voice or sound input device, various types of sensor devices and / or camera devices, and / or output devices such as a display device, a printer, a speaker, and / or a network card. Exemplary input / output devices 78 may be included in the computing device 71 as a component constituting the computing device 71, or may be connected to the computing device 71 as another device separate from the computing device 71.

[0098] The present invention is described in detail above through representative embodiments, but people familiar with the common sense in the technical field can understand that various deformations can be implemented to obtain other equivalent embodiments. Therefore, the true technical protection scope of the present invention should be determined according to the technical ideas of the attached claims.

Claims

1. A spatial multiplexing device, comprising a memory and a processor for executing at least a part of an operation according to a program stored in the memory and included in a transmission node of a wireless network, wherein: The processor is used to: Calculating a simultaneous transmission power based on the density of peripheral access points, the simultaneous transmission power being a power used to transmit a signal simultaneously with an occupied transmission node that is transmitting a signal at a reference transmission power in an occupied channel; Setting an idle channel assessment threshold according to the simultaneous transmission power adjustment; Whether to transmit simultaneously is determined according to the idle channel evaluation threshold and the strength of the signal transmitted from the occupied transmission node.

2. The spatial multiplexing device according to claim 1, wherein: The processor calculates and obtains a simultaneous transmission power that maximizes the product of the transmission success probability of the occupied transmission node and the simultaneous transmission success probability, which is the transmission success probability during simultaneous transmission.

3. The spatial multiplexing device according to claim 1, wherein: When the simultaneous transmission power is not included in a standard transmission power range, the processor causes the transmitting node to postpone transmission so as not to perform simultaneous transmission.

4. The spatial multiplexing device according to claim 1, wherein: When the strength of the signal transmitted from the occupied transmission node is below a clear channel assessment threshold, the processor enables the transmission node to perform simultaneous transmission.

5. The spatial multiplexing device according to claim 1, wherein: In a case where the occupied transmission node is a node constituting an internal basic service set of the same basic service set, the processor sets the reference idle channel assessment threshold to the idle channel assessment threshold.

6. The spatial multiplexing device according to claim 1, wherein: When the occupied transmission node is a node of an external basic service set constituting other basic service sets, the processor sets the idle channel assessment threshold so that the sum of the simultaneous transmission power and the minimum idle channel assessment threshold is equal to the sum of the reference transmission power and the idle channel assessment threshold.

7. The spatial multiplexing device according to claim 1: The processor confirms the density of peripheral access points based on basic service set information obtained through periodic exchange between access points.

8. The spatial multiplexing device according to claim 1, wherein: The processor determines whether the occupied transmission node is a node of an internal basic service set included in the same basic service set or a node of an external basic service set included in other basic service sets based on basic service set color information included in basic service set information obtained through periodic exchange between access points.

9. The spatial multiplexing device according to claim 1, wherein: The transmission node is implemented by a device that occupies a channel using a distributed coordination function based on a carrier sense multiple access / collision avoidance method of IEEE 802.

11.

10. A spatial multiplexing method, executed by a processor of a transmission node included in a wireless network, comprising: The step of calculating a simultaneous transmission power for transmitting a signal simultaneously with an occupied transmission node that is transmitting a signal at a reference transmission power in an occupied channel based on the density of peripheral access points; The step of adjusting the idle channel assessment threshold according to the simultaneous transmission power; as well as The step of determining whether to transmit simultaneously according to the idle channel evaluation threshold and the strength of the signal transmitted from the occupied transmission node.

11. The spatial multiplexing method according to claim 10, in the step of calculating the simultaneous transmission power: The simultaneous transmission power is calculated to maximize the product of the transmission success probability of the occupied transmission node and the simultaneous transmission success probability as the transmission success probability during simultaneous transmission.

12. The spatial multiplexing method according to claim 10, in the step of determining whether to transmit simultaneously: When the simultaneous transmission power is not included in the standard transmission power range, the transmitting node postpones transmission so as not to perform simultaneous transmission.

13. The spatial multiplexing method according to claim 10, in the step of determining whether to transmit simultaneously: When the strength of the signal transmitted from the occupied transmission node is below the idle channel assessment threshold, the transmission node is enabled to perform simultaneous transmission.

14. The spatial multiplexing method according to claim 10, in the step of adjusting and setting the idle channel assessment threshold: When the occupied transmission node is a node of an internal basic service set constituting the same basic service set, the reference idle channel assessment threshold is set to the idle channel assessment threshold.

15. The spatial multiplexing method according to claim 10, in the step of adjusting and setting the idle channel assessment threshold: When the occupied transmission node is a node of an external basic service set constituting other basic service sets, the processor sets the idle channel assessment threshold so that the sum of the simultaneous transmission power and the minimum idle channel assessment threshold is equal to the sum of the reference transmission power and the idle channel assessment threshold.

16. The spatial multiplexing method according to claim 10, in the step of calculating the simultaneous transmission power: The density of peripheral access points is determined based on the basic service set information obtained through periodic exchange between access points.

17. The spatial multiplexing method according to claim 10, in the step of determining whether to transmit simultaneously: According to the basic service set color information contained in the basic service set information obtained through periodic exchange between access points, it is determined whether the occupied transmission node is a node of an internal basic service set contained in the same basic service set or a node of an external basic service set contained in other basic service sets.

18. The spatial multiplexing method according to claim 10, wherein: The transmission node is implemented by a device that occupies a channel using a distributed coordination function based on a carrier sense multiple access / collision avoidance method of IEEE 802.11.

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