WO2017007183A1

WO2017007183A1 - Power control method in wireless communication system and device therefor

Info

Publication number: WO2017007183A1
Application number: PCT/KR2016/007115
Authority: WO
Inventors: 김동철; 이병주; 박기원; 박현희; 임태성
Original assignee: 엘지전자 주식회사
Priority date: 2015-07-03
Filing date: 2016-07-01
Publication date: 2017-01-12

Abstract

The present specification can provide a method by which a wireless device controls power in a wireless communication system, wherein the method by which a wireless device controls power can comprise the steps of: performing a first fine timing measurement (FTM) with another wireless device so as to obtain a first value, which is relative distance information of the other wireless device; and determining transmission power for the other wireless device.

Description

Power control method and apparatus thereof in wireless communication system

The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for controlling power in a wireless communication system.

Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency (SC-FDMA). division multiple access (MCD) systems and multi-carrier frequency division multiple access (MC-FDMA) systems.

In addition, with the development of information and communication technology, various wireless communication technologies have been developed. Among these, WLAN is based on radio frequency technology, and can be used in homes, businesses, or businesses by using portable terminals such as personal digital assistants (PDAs), laptop computers, and portable multimedia players (PMPs). It is a technology that allows wireless access to the Internet in a specific service area.

An object of the present specification is to provide a method and apparatus for controlling power in a wireless communication system.

It is an object of the present specification to provide a method for controlling power based on relative distance information for a wireless device in a wireless communication system.

An object of the present disclosure is to provide a method for efficiently controlling power use by setting a transmission power differential to a maximum transmission power in a wireless communication system.

According to an embodiment of the present disclosure, a method of controlling power by a first wireless device in a wireless communication system may be provided. In this case, the method for controlling power may include performing a first fine timing measurement (FTM) with a second wireless device to obtain a first value, which is relative distance information of the second wireless device, and for the second wireless device. Determining transmission power.

In addition, according to an embodiment of the present disclosure, a first wireless device for controlling power in a wireless communication system may be provided. In this case, the first wireless device may provide a receiving module for receiving the information from the external device, a transmitting module for transmitting the information to the external device, and a processor for controlling the receiving module and the transmitting module. In this case, the processor performs a first fine timing measurement (FTM) with the second wireless device to obtain a first value, which is relative distance information of the second wireless device, and calculates a transmission power for the second wireless device. You can decide.

In addition, the following may be commonly applied to a method and a wireless device for controlling power in a wireless communication system.

According to one embodiment of the present specification, after performing the first FTM with the second wireless device, the second FTM may be performed to obtain a second value that is relative distance information of the second wireless device. At this time, the transmit power for the second wireless device is set to the maximum transmit power before the first FTM is performed and the second FTM is performed, and after the second FTM is performed, the transmit power for the second wireless device is the first value. And based on the second value.

Further, according to one embodiment of the present specification, when the second value is smaller than the first value, the transmission power for the second wireless device after performing the second FTM may be determined based on a ratio of the second value to the second value. have.

In addition, according to one embodiment of the present specification, the transmission power for the second wireless device after performing the second FTM may be a value reduced by the above-mentioned ratio in the maximum transmission power.

Also, according to one embodiment of the present specification, if the second value is greater than or equal to the first value, the transmit power for the second wireless device after performing the second FTM may be set to the maximum transmit power.

In addition, according to an embodiment of the present specification, after performing the second FTM with the second wireless device, the third FTM may be performed to obtain a third value that is relative distance information of the second wireless device.

In this case, after the third FTM is performed, the transmit power for the second wireless device may be determined based on the first value and the third value.

Further, according to one embodiment of the present specification, after the third FTM is performed only when the second value is smaller than the first value, the transmit power for the second wireless device may be determined based on the first value and the third value. have.

Further, according to one embodiment of the present specification, when the second value is greater than or equal to the first value, the transmit power for the second wireless device is set to the maximum transmit power after the second FTM and before the third FTM is performed. And, after the third FTM is performed, the transmit power for the second wireless device may be determined based on the second value and the third value.

In addition, according to one embodiment of the present specification, by performing a second FTM with a third wireless device, a second value, which is relative distance information of the third wireless device, may be obtained, and transmission power for the third wireless device may be determined. .

In this case, when the first value is greater than or equal to the second value, the transmit power for the second wireless device is set to the maximum transmit power, and the transmit power for the third wireless device is in the ratio of the second value to the first value. Can be determined based on this.

In this case, the transmission power for the third wireless device may be a value reduced by the above ratio in the maximum transmission power.

The present disclosure can provide a method and apparatus for controlling power in a wireless communication system.

The present disclosure may provide a method of controlling power based on relative distance information for a wireless device in a wireless communication system.

In the present specification, power usage may be efficiently controlled through a transmission power setting that is differential from the maximum transmission power in a wireless communication system.

Effects obtained in the present specification are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a diagram illustrating an exemplary structure of an IEEE 802.11 system.

2 to 3 are diagrams illustrating a NAN cluster.

4 is a diagram illustrating how FTM is performed in a plurality of wireless devices.

5 is a diagram illustrating parameters used in an FTM procedure.

6 is a diagram illustrating a method of performing an FTM procedure.

7 and 8 illustrate a method of controlling power based on the relative distance of a wireless device.

9 and 10 are flowcharts illustrating a method of controlling power by a terminal according to one embodiment of the present specification.

11 is a block diagram of a terminal device according to one embodiment of the present specification.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

The following embodiments combine the components and features of the present invention in a predetermined form. Each component or feature may be considered to be optional unless otherwise stated. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, some components and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

In some instances, well-known structures and devices are omitted or shown in block diagram form, centering on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802 system, 3GPP system, 3GPP LTE and LTE-A (LTE-Advanced) system and 3GPP2 system. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various radio access systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA).

In addition, terms such as first and / or second may be used herein to describe various components, but the components should not be limited by the terms. The terms are only for the purpose of distinguishing one component from another component, for example, without departing from the scope of rights in accordance with the concepts herein, the first component may be called a second component, and similarly The second component may also be referred to as a first component.

In addition, throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless otherwise stated. And “…” described in the specification. unit", "… “Unit” refers to a unit that processes at least one function or operation, which may be implemented in a combination of hardware and / or software.

Hereinafter, for the sake of clarity, the following description focuses on the IEEE 802.11 system, but the technical spirit of the present invention is not limited thereto.

1 is a diagram showing an exemplary structure of an IEEE 802.11 system to which the present invention can be applied.

The IEEE 802.11 architecture may be composed of a plurality of components, and by their interaction, a WLAN may be provided that supports transparent STA mobility for higher layers. The Basic Service Set (BSS) may correspond to a basic building block in an IEEE 802.11 WLAN. FIG. 1 exemplarily shows that two BSSs (BSS1 and BSS2) exist and include two STAs as members of each BSS (STA1 and STA2 are included in BSS1 and STA3 and STA4 are included in BSS2). do. In FIG. 1, an ellipse representing a BSS may be understood to represent a coverage area where STAs included in the BSS maintain communication. This area may be referred to as a basic service area (BSA). When the STA moves out of the BSA, the STA cannot directly communicate with other STAs in the BSA.

The most basic type of BSS in an IEEE 802.11 WLAN is an independent BSS (IBSS). For example, the IBSS may have a minimal form consisting of only two STAs. In addition, the BSS (BSS1 or BSS2) of FIG. 1, which is the simplest form and other components are omitted, may correspond to a representative example of the IBSS. This configuration is possible when STAs can communicate directly. In addition, this type of WLAN is not configured in advance, but may be configured when a WLAN is required, and may be referred to as an ad-hoc network.

The membership of the STA in the BSS may be dynamically changed by turning the STA on or off, the STA entering or exiting the BSS region, and the like. In order to become a member of the BSS, the STA may join the BSS using a synchronization process. In order to access all services of the BSS infrastructure, the STA must be associated with the BSS. This association may be set up dynamically and may include the use of a Distribution System Service (DSS).

In addition, FIG. 1 illustrates components of a distribution system (DS), a distribution system medium (DSM), an access point (AP), and the like.

The station-to-station distance directly in the WLAN may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in some cases, communication between more distant stations may be necessary. The distribution system DS may be configured to support extended coverage.

DS refers to a structure in which BSSs are interconnected. Specifically, instead of the BSS independently as shown in FIG. 1, the BSS may exist as an extended type component of a network composed of a plurality of BSSs.

DS is a logical concept and can be specified by the nature of the distribution system medium (DSM). In this regard, the IEEE 802.11 standard logically distinguishes between wireless medium (WM) and distribution system media (DSM). Each logical medium is used for a different purpose and is used by different components. The definition of the IEEE 802.11 standard does not limit these media to the same or to different ones. In this way the plurality of media are logically different, the flexibility of the IEEE 802.11 WLAN structure (DS structure or other network structure) can be described. That is, the IEEE 802.11 WLAN structure can be implemented in various ways, the corresponding WLAN structure can be specified independently by the physical characteristics of each implementation.

The DS may support the mobile device by providing seamless integration of multiple BSSs and providing logical services for handling addresses to destinations.

An AP refers to an entity that enables access to a DS through WM for associated STAs and has STA functionality. Data movement between the BSS and the DS may be performed through the AP. For example, STA2 and STA3 shown in FIG. 1 have the functionality of a STA, and provide a function to allow associated STAs STA1 and STA4 to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM need not necessarily be the same.

Data transmitted from one of the STAs associated with an AP to the STA address of that AP may always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. In addition, when a controlled port is authenticated, transmission data (or frame) may be transmitted to the DS.

In addition, the operation of the STA operating in the WLAN system may be described in terms of a layer structure. In terms of device configuration the hierarchy may be implemented by a processor. The STA may have a plurality of hierarchical structures. For example, the hierarchical structure covered by the 802.11 standard document is mainly the MAC sublayer and physical (PHY) layer on the DLL (Data Link Layer). The PHY may include a Physical Layer Convergence Procedure (PLCP) entity, a Physical Medium Dependent (PMD) entity, and the like. The MAC sublayer and PHY conceptually contain management entities called MAC sublayer management entities (MLMEs) and physical layer management entities (PLMEs), respectively.These entities provide a layer management service interface on which layer management functions operate. .

In order to provide correct MAC operation, a Station Management Entity (SME) is present in each STA. An SME is a layer-independent entity that can appear to be in a separate management plane or appear to be off to the side. While the exact features of the SME are not described in detail in this document, they generally do not include the ability to collect layer-dependent states from various Layer Management Entities (LMEs), and to set similar values for layer-specific parameters. You may seem to be in charge. SMEs can generally perform these functions on behalf of general system management entities and implement standard management protocols.

The aforementioned entities interact in a variety of ways. For example, entities can interact by exchanging GET / SET primitives. A primitive means a set of elements or parameters related to a particular purpose. The XX-GET.request primitive is used to request the value of a given MIB attribute (management information based attribute information). The XX-GET.confirm primitive is used to return the appropriate MIB attribute information value if the Status is "Success", otherwise it is used to return an error indication in the Status field. The XX-SET.request primitive is used to request that the indicated MIB attribute be set to a given value. If the MIB attribute means a specific operation, this is to request that the operation be performed. And, the XX-SET.confirm primitive confirms that the indicated MIB attribute is set to the requested value when status is "success", otherwise it is used to return an error condition in the status field. If the MIB attribute means a specific operation, this confirms that the operation has been performed.

In addition, the MLME and SME may exchange various MLME_GET / SET primitives through a MLME_SAP (Service Access Point). In addition, various PLME_GET / SET primitives may be exchanged between PLME and SME through PLME_SAP and may be exchanged between MLME and PLME through MLME-PLME_SAP.

The wireless device can operate based on the NAN network. In this case, the NAN network may be configured with NAN terminals using the same set of NAN parameters (eg, time intervals between successive discovery windows, intervals of discovery windows, beacon intervals, or NAN channels, etc.). The NAN terminals may configure a NAN cluster, where the NAN cluster uses the same set of NAN parameters and means a set of NAN terminals synchronized to the same discovery window schedule. 2 shows an example of a NAN cluster. A NAN terminal belonging to a NAN cluster may directly transmit a multicast / unicast NAN service discovery frame to another NAN terminal within a range of a discovery window. As shown in FIG. 3, one or more NAN masters may exist in the NAN cluster, and the NAN master may be changed. In addition, the NAN master may transmit both a sync beacon frame, a discovery beacon frame, and a NAN service discovery frame.

As mentioned above, wireless devices may be operated based on a WLAN or NAN network. In addition, it may also be possible to operate based on other communication systems such as Peer to Peer (P2P), Near Field Communication (NFC), Bluetooth Low Energy (BLE), and the like, but is not limited to the above-described embodiment.

Hereinafter, a method of controlling power based on a fine timing measurement (FTM) capable of measuring position information as a relative distance between devices for wireless devices that can operate in various communication systems will be described.

FTM may be performed to obtain location information as a relative distance between wireless devices. The wireless device requesting to perform the FTM may be an initiating STA (hereinafter referred to as a first wireless device), and the wireless device providing a response may be a responding STA (hereinafter referred to as a second wireless device). In this case, as an example, the first wireless device may perform an FTM procedure with the plurality of second wireless devices. That is, the first wireless device may include a plurality of coexisting FTM sessions.

In addition, an FTM session may consist of negotiation, measurement, and termination. That is, the first wireless device may obtain relative distance or position information with the second wireless device through frame exchange in the negotiation and measurement process with the second wireless device.

For example, referring to FIG. 4, the first wireless device may exchange an FTM frame with a second wireless device in a predetermined time window as a burst instance. In this way, the first wireless device can perform FTM with the second wireless device. In addition, as an example, as described above, the first wireless device may perform an FTM procedure using different channels from the plurality of second wireless devices. In this case, as an example, time intervals for exchanging frames with respective second wireless devices may overlap. The first wireless device may adjust the burst instance as a time interval for each second wireless device to prevent collision.

5 is a diagram illustrating parameters used in the FTM. As described above with reference to FIG. 4, the first wireless device and the second wireless device may perform FTM by exchanging frames within a predetermined time interval. In this case, as an example, the first wireless device may transmit an FTM request frame to the second wireless device to perform the FTM. In this case, the second wireless device may transmit a response frame based on the FTM request frame.

In this case, as an example, the FTM parameters may be included in a frame exchanged between the first wireless device and the second wireless device. For example, referring to FIG. 5A, a frame used in an FTM may include at least one of an Element ID, a Length, and an FTM Parameter field. Also, referring to FIG. (B), the FTM Parameter field includes Status Indication, Value, Number of Burst Exponent, Burst Duration, Min Delta FTM, Partial TSF Timer, ASAP Capable, ASAP, FTMs per Burst, FTM Format And Bandwidth, Burst At least one or more of the Period fields may be included. The first wireless device and the second wireless device may perform FTM using the parameter defined by the above-described fields. The above parameters are replaced with the contents disclosed in the document Draft + P802.11REVmc_D4.0.

6 is a diagram illustrating a method of performing FTM. As described above, the first wireless device may perform FTM by exchanging a frame within a predetermined time interval with the second wireless device.

In this case, referring to FIG. 6 as an example, the first wireless device may transmit an FTM request to the second wireless device as an FTM trigger frame. In this case, the second wireless device may transmit an ACK for confirming whether the FTM request is received to the first wireless device. Thereafter, the FTM Response can be sent to the first wireless device. In this case, the first wireless device may transmit an ACK frame confirming whether the FTM response is received. In this case, as an example, the FTM trigger frame is a frame for starting the FTM and may not include the parameters disclosed in FIG. 4. In addition, the FTM response frame may be a frame indicating that the FTM may be started as a response to the FTM trigger frame.

Thereafter, the first wireless device may transmit an FTM request frame for FTM measurement to the second wireless device within a burst instance. In this case, as an example, the partial TSF timer may mean a time at which the first instance of time is started. The second wireless device can then send an ACK confirming receipt of the FTM request frame. The second wireless device can then send a Burst FTM frame to the first wireless device. In this case, the time when the first wireless device transmits the Burst FTM frame may be t1. In addition, the time at which the second wireless device receives the Burst FTM frame may be t2. Thereafter, the second wireless device may send an ACK as an acknowledgment for the Burst FTM frame. In this case, the time when the second wireless device transmits the ACK may be t3. In addition, the time at which the first wireless device receives the ACK may be t4.

In this case, as an example, the first wireless device may calculate a round trip time (RTT) using the aforementioned t1 to t4. That is, the first wireless device can measure the time required for transmitting and receiving Burst FTM frames and ACKs transmitted by the second wireless device. In more detail, RTT may be the same as Equation 1 below.

[Equation 1]

The RTT may be a value obtained by subtracting (minus) a time when the second wireless device receives the Burst FTM frame and transmits the ACK after the second wireless device receives the ACK after transmitting the Burst FTM frame. That is, the RTT may mean a time at which the first wireless device and the second wireless device exchange signals.

In this case, as an example, the relative distance between the first wireless device and the second wireless device may be determined by Equation 2 below based on the RTT.

[Equation 2]

Where C is

(m / sec), and D may be a distance. That is, the relative distance between the first wireless device and the second wireless device may be calculated by calculating a value multiplied by the speed of the signal at the time when the signal is transmitted. In addition, as an example, when the location of the first wireless device is known, the location information of the second wireless device may be acquired, and the present invention is not limited to the above-described embodiment.

As mentioned above, the wireless device may operate based on various communication systems. In this case, for example, when the wireless device operates in a limited space such as WLAN or NAN, it is necessary to operate in consideration of the range and power of the space as a space provided with one cluster or communication system. . Also, for example, the plurality of wireless devices may form a group, and there is a need for an operation to be performed in consideration of the number and location of the plurality of wireless devices in the group. In addition, with the increase in the use of smart phones or the development of the Internet of Things (IoT), there are cases where a plurality of wireless devices exist in a limited space. In this case, there may be a need for a method of controlling power for each of the wireless devices.

Hereinafter, a method of controlling power by using relative distance or position information between wireless devices based on the above-described FTM will be described.

In this case, for example, referring to FIG. 7, a plurality of wireless devices may exist in one space. In this case, for example, one space may be a space where a communication service is provided. For example, one cluster in the above-described NAN may be one space. In this case, the first wireless device 710 and the second wireless device 720 may be operating in one space. In this case, as an example, the first wireless device 710 may be the initiating STA described above, and the second wireless device 720 may be the responding STA. In this case, as an example, relative distance information may be obtained by performing the above-described FTM with the first wireless device 710 and the second wireless device 720.

More specifically, the first wireless device 710 can perform an FTM with the second wireless device 720. In this case, as an example, the first wireless device 710 may transmit a signal at the maximum transmit power until the FTM is completed. In this case, as an example, the maximum transmit power may be set differently in each wireless device, and is not limited to the above-described embodiment. In this case, the first wireless device 710 may perform FTM to obtain relative distance information. In this case, the first wireless device 710 may set the transmission power differently for each distance by matching the transmission power information with the relative distance information.

As an example, the first wireless device 710 may match the maximum transmit power value to the current relative distance information. That is, in the relative distance information based on the current FTM performance result, a signal may be transmitted at the maximum transmission power.

The first wireless device 710 can then perform the next FTM. In this case, as an example, the FTM may be performed based on a certain period. Information on a certain period may be defined based on the parameters for the FTM described above.

When the FTM is updated, the first wireless device 710 and the second wireless device 720 may obtain new relative distance information. In this case, the first wireless device 710 and the second wireless device 720 may control the transmission power based on the new relative distance information. For example, the relative distance information obtained by performing the first FTM may be a first value. In this case, the first FTM may refer to an FTM in which the first wireless device 710 and the second wireless device 720 are connected to the cluster or system for the first time. Also, as an example, the first wireless device 710 and the second wireless device 720 may mean an FTM that awakes and attempts, but is not limited to the above-described embodiment.

In addition, the FTM for obtaining the reference value as the relative distance information between the first wireless device 710 and the second wireless device 720 may be the first FTM, and is not limited to the above-described embodiment.

The first wireless device 710 and the second wireless device 720 may perform the next FTM after the first FTM. In this case, as an example, the relative distance information obtained by the first wireless device 710 and the second wireless device 720 through the FTM may be a second value.

That is, relative distance information that is changed in consideration of mobility of the first wireless device 710 and the second wireless device 720 may be measured through the next FTM.

In this case, the transmission power may be controlled based on the first value and the second value. In this case, as an example, when the second value is the first value, the first wireless device 710 may maintain the maximum transmit power value. That is, the first wireless device 710 and the second wireless device 720 may transmit a signal while maintaining the maximum transmission power when the relative distance is increased.

Also, as an example, when the first value is greater than the second value, the first wireless device 710 may reduce the transmit power based on the ratio of the first value to the second value. For example, the transmission power may be determined based on Equation 3 below.

[Equation 3]

In this case, TxP_Current may be the current transmission power, and TxP_Previous may mean the previous transmission power. In addition, N * X may be a value determined by the first value and the second value. For example, whenever N * 10% is reduced, N * X (dB) may be subtracted from the maximum transmission power. For example, when the second value is reduced by 10% than the first value, it may be expressed as Equation 4.

[Equation 4]

In this case, X may be a power reduction corresponding to 10% based on the maximum transmit power. In this case, the 10% unit may be an example, the sub-value may be set differently, and the X value may also be changed.

That is, the transmit power value for the first wireless device 710 may be set to a value reduced by a ratio of a first value, which is the relative distance information obtained by the first FTM, and a second value, which is the relative distance information obtained by the current FTM. Can be. Through this, in one space, the wireless devices can control the transmission power based on the relative distance of the wireless devices.

In this case, as an example, the above-described configuration may be a configuration performed based on one external device as a relationship between the first wireless device 710 and the second wireless device 720.

In this case, in the above-described embodiment, the relative distance information, which is a reference in the embodiment of controlling the transmission power in preparation for the relative distance information, may be relative distance information acquired by the first FTM.

That is, the first wireless device 710 and the second wireless device 720 may first obtain a first value as relative distance information through the first FTM. Next, the first wireless device 710 and the second wireless device 720 may obtain a second value as relative distance information through the second FTM. Next, the first wireless device 710 and the second wireless device 720 may obtain a third value as relative distance information through the third FTM.

In this case, as an example, after performing the second FTM, the transmission power of the first wireless device 710 may be determined based on a comparison result of the second value based on the first value. Then, when the third FTM is performed, the transmit power of the first wireless device 710 may be determined based on the comparison result of the third value based on the first value. That is, the reference value of the relative distance information may be relative distance information obtained from the first performed FTM.

However, as an example, when the third FTM is performed, the first wireless device 710 may compare the third value based on the second value to control the transmission power based on the relative distance information.

As another example, when the obtained relative distance information is larger than the previous relative distance information (when the second value is larger than the first value in the above-described embodiment), the transmission power may be controlled based on the obtained relative distance information. have.

That is, when the relative distance information obtained through the FTM is smaller than the relative distance information acquired in the first FTM, the transmission power may be reduced from the maximum transmission power based on the ratio to the relative distance as described above. However, when the relative distance information obtained by performing the FTM is larger than the relative distance information obtained by the first FTM, the maximum transmission power may be set as described above. At the same time, the reference value for the relative distance information can be updated. In this case, when the relative distance information is obtained based on the next FTM, the transmission power may be reduced based on the updated relative distance information.

That is, as an example, the first FTM may be a case where the relative distance information is larger than the previous relative distance information, and is not limited to the above-described embodiment.

As another example, referring to FIG. 8, a plurality of wireless devices may exist in a range in which a communication system is provided as one cluster or one space.

In this case, as an example, the first wireless device 810 may perform an FTM with the second wireless device 820, the third wireless device 830, and the fourth wireless device 840. That is, the first wireless device 810 can obtain relative distance information for each of the

wireless devices

810, 820, and 830. In this case, as an example, the first wireless device 810 may be the initiating STA described above, and the second wireless device 820, the third wireless device 830, and the fourth wireless device 840 may be the responding STA described above. .

In this case, as an example, the first wireless device 810 may determine relative distance information of the wireless device having the farthest relative distance as a reference value and transmit a signal at the maximum transmission power. In addition, the first wireless device 820 may set transmission powers for other wireless devices based on the relative distance information on the wireless device having the farthest relative distance, based on

Equations

3 and 4 described above. For example, even in the above-described case, the continuous FTM may be performed, and the maximum transmission power may be set based on the maximum transmission power for the wireless device having the largest relative distance value in the first FTM, and the transmission power may be controlled as described above. Can be.

In more detail, as an example, referring to FIG. 8, the first wireless device 810 may perform FTM with each of the

wireless devices

820, 830, and 840 to obtain relative distance information. In this case, the relative distance information of the second wireless device 820 may be a second value. In addition, the relative distance information of the third wireless device 830 may be a third value. In addition, the relative distance information of the fourth wireless device 840 may be a fourth value.

In this case, as an example, the fourth value may be greater than the second value and the third value. In this case, when transmitting a signal for the fourth wireless device 840, the first wireless device 810 may transmit at the maximum transmission power. The largest transmit power can be set to the wireless device 840 located farthest in one space or cluster. That is, high transmission power may be required for the wireless device having the largest relative distance with the first wireless device 810, and thus, there is a need to set the maximum transmission power.

In this case, as an example, the transmission power for the case where the first wireless device 810 transmits a signal to the second wireless device 820 may be determined by comparing the second value based on the fourth value. That is, the transmit power for the second wireless device 820 may be a value reduced by the ratio of the fourth value and the second value at the maximum transmit power. In addition, the transmit power for the third wireless device 830 may be a value reduced by the ratio of the fourth value and the third value at the maximum transmit power. This allows the first wireless device 810 to efficiently control power based on the relative distance.

In addition, as an example, even if the FTM is additionally performed, the fourth value may be maintained, and based on this, relative distance information values of respective wireless devices may be compared to set a maximum transmit power.

As another example, when the FTM procedure is performed, when the relative distance information higher than the fourth value is obtained, the maximum transmit power may be set. At the same time, the reference value for the relative distance information can be updated. That is, a reference value may be set to a value corresponding to higher relative distance information, and a transmission power value may be determined based on the reference value, which is not limited to the above-described embodiment.

In addition, as an example, the wireless devices may exchange relative distance information and transmit power information through the FTM. In this case, regardless of a specific frame or frame type, the corresponding information may be included and shared. In this case, as an example, each of the wireless devices may determine the transmission power based on the above information. That is, each of the wireless devices can determine the transmission power using the relative distance information and the transmission power information as one information. In addition, as an example, the wireless device may use information that affects transmission power, such as modulation coding scheme (MCS) level, received signal strength indicator (RSSI) information, link margin information, etc. have.

That is, each of the wireless devices may receive and use the relative distance information and the transmission power information from other wireless devices as information for determining the transmission power, and are not limited to the above-described embodiment.

In addition, in the process of continuously tracking the distance and the transmission power level using the above-described methods, the power level can be statically / semi-statically adjusted in steps so that the power level can be operated only as much as necessary.

To this end, it may be necessary to receive and use feedback information from an external device as described above. In addition, as an example, each of the wireless devices may share the transmission power for the current frame transmission, and the counterpart device may need to feed back information corresponding to the link margin for this, and may control the transmission power by using the same. have.

In addition, as an example, an embodiment of obtaining the relative distance may use a procedure other than the above-described FTM, and is not limited to the above-described embodiment.

9 is a flowchart illustrating a method for controlling power by a terminal according to an embodiment of the present specification.

The first wireless device may perform a first FTM with the second wireless device to obtain a first value which is relative distance information of the second wireless device. (S910) In this case, as described above with reference to FIGS. The first wireless device may obtain relative distance information for the second wireless device through the FTM. Also, as an example, the first wireless device may obtain relative distance information about the second wireless device through another method, and is not limited to the above-described embodiment.

Next, after performing the first FTM with the second wireless device, the first wireless device may perform a second FTM procedure to acquire a second value that is relative distance information of the second wireless device (S920). As described above in FIGS. 1 to 8, the second FTM may be performed after the first FTM. That is, relative distance information that is changed in consideration of mobility of the second wireless device may be measured.

In this case, the first wireless device may set the transmission power for the second wireless device to the maximum transmission power until the first FTM is performed and the second FTM is performed (S930). Likewise, as an example, the first FTM may mean the original FTM procedure. That is, after the first FTM is performed, the transmission power may be set to the maximum until the next FTM is performed.

Next, the first wireless device may determine the transmit power for the second wireless device after the second FTM is performed (S940). As described above with reference to FIGS. 1 to 8, for example, the second value may be determined. If greater than or equal to the first value, the transmit power for the second wireless device may be set to the maximum transmit power (S950). That is, if the relative distance is increased in the next FTM, the transmit power may be maintained at the maximum transmit power. have. In addition, when the second value is smaller than the first value, the transmission power for the second wireless device may be set to a value reduced by a ratio of the second value to the first value (S960). As described above in FIG. 8, the transmit power for the second wireless device may be set to a value reduced by a ratio of the second value to the first value at the maximum transmit power. That is, when the relative distance is reduced, the power consumption may be reduced by reducing the transmission power.

In this case, as an example, the reference value of the relative distance with respect to the maximum transmission power may be a first value. In this case, when the third FTM is performed and the third value, which is the relative distance information, is smaller than the first value, the transmit power may be set to a value reduced by a ratio of the third value to the first value at the maximum transmit power. That is, the first value may be a reference value.

However, when the second value is greater than or equal to the first value as a result of performing the second FTM, the reference value of the relative distance information may be updated to the second value, as described above.

10 is a flowchart illustrating a method of controlling power by a terminal according to an embodiment of the present specification.

The first wireless device may perform a first FTM with the second wireless device to obtain a first value, which is relative distance information of the second wireless device. (S1010) Next, the first wireless device connects with the third wireless device. 2 FTM may be performed to obtain a second value that is relative distance information of the third wireless device (S1020). As described above with reference to FIGS. 1 to 8, a plurality of spaces (or groups or clusters) may be provided. Wireless devices may coexist. In addition, the first wireless device may perform FTM with a plurality of wireless devices to obtain relative distance information for each device, as described above. In this case, the following describes a case where the first wireless device, the second wireless device, and the third wireless device coexist, but the same may also be applied to the case where more wireless devices coexist.

Next, the first wireless device may determine transmit power for the second wireless device and the third wireless device.

In this case, when the first value is greater than or equal to the second value, the transmit power for the second wireless device may be determined as the maximum transmit power. (1040) In this case, as described above with reference to FIGS. The device may set the maximum transmit power for the wireless device having the largest relative distance among the plurality of wireless devices in one space. More specifically, high transmission power may be required for the wireless device having the largest relative distance from the first wireless device, and thus, there is a need to set the maximum transmission power. In this case, the transmission power for the third wireless device may be set to a value reduced by the ratio of the second value to the first value at the maximum transmission power. (S1050) At this time, as described above with reference to FIGS. 1 to 8, The first wireless device can reduce the transmission power in consideration of each relative distance based on the maximum transmission power that is the transmission power for the farthest wireless device, thereby efficiently controlling the power.

11 is a block diagram of a wireless device according to one embodiment of the present specification.

The wireless device may be a device that operates based on various wireless communication systems.

In this case, the wireless device 100 includes a transmitting module 110 for transmitting a wireless signal, a receiving module 130 for receiving a wireless signal, and a processor 120 for controlling the transmitting module 110 and the receiving module 130. can do. In this case, the wireless device 100 may communicate with an external device using the transmission module 110 and the reception module 130. In this case, the external device may be another wireless device. In addition, the external device may be a base station. That is, the external device may be a device capable of communicating with the wireless device 100 and is not limited to the above-described embodiment. The wireless device 100 may transmit and receive digital data (or a signal) such as content using the transmission module 110 and the reception module 130. In addition, the wireless device 100 may exchange signals for a frame and the like by using the transmitting module 110 and the receiving module 130 and is not limited to the above-described embodiment. That is, the wireless device 100 may exchange information with an external device by performing communication using the transmitting module 110 and the receiving module 130.

According to an embodiment of the present disclosure, the processor 120 of the first wireless device 100 performs a first FTM with the second wireless device to obtain a first value which is relative distance information of the second wireless device, 2 may determine transmit power for the wireless device.

In this case, according to an embodiment, the processor 120 of the first wireless device 100 performs a second FTM after performing the first FTM with the second wireless device, thereby performing the second distance that is the relative distance information of the second wireless device. The value can be obtained further. In this case, the processor 120 may set the transmission power for the second wireless device as the maximum transmission power until the first FTM is performed and the second FTM is performed. In addition, the processor 120 may determine the transmit power for the second wireless device based on the first value and the second value after the second FTM is performed.

Further, according to an embodiment, the processor 120 of the wireless device 100 performs a second FTM with the third wireless device to obtain a second value which is relative distance information of the third wireless device, and the third wireless device It is possible to determine the transmit power for. Also, when the first value is greater than or equal to the second value, the processor 120 may set the transmit power for the second wireless device as the maximum transmit power. In addition, the processor 120 may determine the transmission power for the third wireless device based on the ratio of the second value to the first value.

Embodiments of the present invention described above may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For implementation in hardware, a method according to embodiments of the present invention may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), and Programmable Logic Devices (PLDs). It may be implemented by field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of a module, a procedure, or a function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, while the preferred embodiments of the present specification have been shown and described, the present specification is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present specification claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present specification.

In the present specification, both the object invention and the method invention are described, and the description of both inventions may be supplementarily applied as necessary.

In the above-described wireless communication system, a method for controlling power by the terminal may be applied to various wireless communication systems.

Claims

A method for controlling power by a first wireless device in a wireless communication system, the method comprising:

Performing a first fine timing measurement (FTM) with a second wireless device to obtain a first value which is relative distance information of the second wireless device; And

Determining a transmit power for the second wireless device.
The method of claim 1,

And performing a second FTM after performing the first FTM with the second wireless device to obtain a second value which is relative distance information of the second wireless device.

The transmit power for the second wireless device is set to the maximum transmit power until the first FTM is performed and the second FTM is performed,

And wherein the transmit power for the second wireless device is determined based on the first value and the second value after the second FTM is performed.
The method of claim 2,

If the second value is less than the first value, the transmit power for the second wireless device after performing the second FTM is determined based on a ratio of the second value to the first value Way.
The method of claim 3, wherein

And wherein the transmit power for the second wireless device after performing the second FTM is a value reduced by the ratio from the maximum transmit power.
The method of claim 2,

If the second value is greater than or equal to the first value, the transmit power for the second wireless device is set to the maximum transmit power after performing the second FTM.
The method of claim 2,

And performing a third FTM after performing the second FTM with the second wireless device to obtain a third value which is relative distance information of the second wireless device.
The method of claim 6,

And wherein the transmit power for the second wireless device is determined based on the first value and the third value after the third FTM is performed.
The method of claim 7, wherein

Transmit power control, wherein the transmit power for the second wireless device is determined based on the first value and the third value after the third FTM is performed only if the second value is less than the first value Way.
The method of claim 7, wherein

If the second value is greater than or equal to the first value, the transmit power for the second wireless device is set to the maximum transmit power after performing the second FTM and before the third FTM is performed,

And wherein the transmit power for the second wireless device is determined based on the second value and the third value after the third FTM is performed.
The method of claim 1,

Performing a second FTM with the third wireless device to obtain a second value that is relative distance information of the third wireless device; And

Determining a transmit power for the third wireless device.
The method of claim 10,

If the first value is greater than or equal to the second value, the transmit power for the second wireless device is set to a maximum transmit power,

The transmit power for the third wireless device is determined based on a ratio of the second value to the first value.
The method of claim 11,

Wherein the transmit power for the third wireless device is a value reduced by the ratio from the maximum transmit power.
A first wireless device for controlling power in a wireless communication system,

A receiving module for receiving the information from an external device;

A transmission module for transmitting the information to an external device; And

A processor for controlling the receiving module and the transmitting module,

The processor,

Perform a first fine timing measurement (FTM) with the second wireless device to obtain a first value which is relative distance information of the second wireless device,

A first wireless device controlling transmit power, determining a transmit power for the second wireless device.
The method of claim 13,

The processor,

After performing the second FTM with the second wireless device, the second FTM is further obtained to obtain a second value, which is relative distance information of the second wireless device,

The transmit power for the second wireless device is set to the maximum transmit power until the first FTM is performed and the second FTM is performed,

Wherein the transmit power for the second wireless device is determined based on the first value and the second value after the second FTM is performed.
The method of claim 13,

The processor,

Perform a second FTM with a third wireless device to obtain a second value, which is relative distance information of the third wireless device, and further determine transmit power for the third wireless device;

If the first value is greater than or equal to the second value, the transmit power for the second wireless device is set to a maximum transmit power,

Wherein the transmit power for the third wireless device is determined based on a ratio of the second value to the first value.