WO2014084665A1

WO2014084665A1 - Method for allocating resources in wireless lan system and wireless lan system

Info

Publication number: WO2014084665A1
Application number: PCT/KR2013/011012
Authority: WO
Inventors: 이재승; 정민호; 권형진; 이석규; 정운철; 신창섭; 표철식
Original assignee: 한국전자통신연구원
Priority date: 2012-11-30
Filing date: 2013-11-29
Publication date: 2014-06-05

Abstract

Disclosed are a method for allocating resources in a wireless LAN system and a wireless LAN system. The wireless LAN system according to one embodiment of the present invention may comprise: an access point for allocating resources for communication between a relay and a station connected to the relay; the relay for allocating a restricted access window or slot for the communication with the station based on the allocated resources; and a station for communicating with the relay based on the allocated restricted access window or slot.

Description

Resource Allocation Method in Wireless LAN System, Wireless LAN System

The following description relates to a method of allocating resources in a WLAN system.

Recently, in a WLAN system, slotted channel access has been introduced to reduce collisions between STAs when BSS (Basic Service Set) operations involving thousands of stations are performed. If thousands of STAs try to access the channel at the same time and try to transmit, the probability of collision increases.In the slotted channel access method, RAW (Restricted Access Window) is set to prevent collisions. Divide by) Slots that allow transmission are allocated for each STA, and the STA reduces contention by distributing channel access at a moment by allowing contention for transmission only in slots to which the STA is allocated.

In addition, in order to further extend the coverage of an access point (AP), a WLAN system introduces a relay operation. Even when using the relay method, it is preferable to use the slotted method to efficiently support the transmission of a large number of STAs.

In one embodiment, a WLAN system includes: an access point for allocating resources for communication between a relay and a station connected to the relay; A relay for allocating a restricted access window or slot for communication with the station based on the allocated resources; And a station in communication with the relay based on the assigned restricted access window or slot.

In one embodiment, an access point includes a resource allocator for allocating resources for communication between a relay and a station connected to the relay; And a communication unit for transmitting the information about the allocated resource to the relay.

The relay according to an embodiment may include: a resource allocator configured to allocate resources for communication between the relay and a station connected to the relay based on resource allocation information received from an access point; And a communication unit for transmitting the information about the allocated resource to the station.

In one embodiment, a station includes: a controller for identifying a resource allocated to a station based on a beacon received from a relay; And a communication unit configured to communicate with the relay based on the identified resource.

In a WLAN system including an access point, a relay, and a station according to an embodiment, a resource allocation method performed by the access point may include communication between the access point and the relay, and communication between the access point and the access point. Allocating a first resource for communication between connected stations; And allocating a second resource for communication between the relay and the station connected to the relay.

A resource allocation method performed by an access point according to an embodiment may further include transmitting resource allocation information about the allocated second resource to the relay.

The resource allocation method performed by the access point according to an embodiment may further include adjusting the allocated second resource based on the interference information received from the relay.

The resource allocation method performed by the access point according to an embodiment may further include adjusting the allocated second resource based on the station information received from the relay.

A resource allocation method performed by an access point according to an embodiment may further include transmitting a beacon including information about the allocated first resource and the allocated second resource to the relay.

In a WLAN system including an access point, a relay, and a station according to an embodiment, the resource allocation method performed by the relay includes: receiving resource allocation information from the access point; And allocating a resource for communication between the relay and the station connected to the relay based on the received resource allocation information.

The resource allocation method performed by the relay according to an embodiment may further include transmitting a beacon including the information about the allocated resource to the station.

In a wireless LAN system comprising an access point, a relay, and a station, the communication method performed by the station includes: identifying resources allocated to the station based on a beacon received from the relay; And communicating with the relay based on the identified resource.

1 is a diagram illustrating an example of a method for transmitting data using a relay in a WLAN system according to an embodiment.

2 is a diagram illustrating an example of a basic service set (BSS) configuration when using a relay method according to an embodiment.

3 is a diagram illustrating an example of a method of using a restricted access window (RAW) when using a relay according to an embodiment.

4 is a diagram illustrating another example of a method of using a limited access window when using a relay according to an embodiment.

5 illustrates another example of a method of using a restricted access window when using a relay according to an embodiment.

6 illustrates a RAW structure in a slotted transmission scheme according to an embodiment.

7 illustrates an example of sharing the same RAW using different channels according to an embodiment.

8 through 9 are diagrams illustrating an example of allocating a plurality of clusters to one RAW by using offset information, according to an exemplary embodiment.

10 is a diagram for describing a method of assigning an AID to a cluster, according to an exemplary embodiment.

FIG. 11 is a diagram illustrating an allocation position of a beacon transmitted by a relay AP (R-AP) according to an embodiment.

12 is a diagram for describing a method of allocating slots for STAs according to an embodiment.

FIG. 13 illustrates a simplified leveled slot allocation according to an embodiment. FIG.

14 is a diagram illustrating a RAW allocation method for a relay when a plurality of relays are used according to an embodiment.

15 is a diagram illustrating an example of a RAW allocation method when a plurality of relays are used according to an embodiment.

16 illustrates an example of a RAW allocation method for a relay when a plurality of relays are used according to another embodiment.

17 is a diagram illustrating a leveled slot allocation method in a more generalized form according to an embodiment.

18 illustrates an example of a leveled slot allocation method using an empty slot according to an embodiment.

19 illustrates an example of a leveled slot allocation method using an empty slot according to another embodiment.

20 illustrates an example of a leveled slot allocation method using empty RAW according to an embodiment.

21 illustrates an example of a leveled slot allocation method using empty RAW according to another embodiment.

22 illustrates an example of a leveled slot allocation method using sub RAW according to an embodiment.

FIG. 23 is a diagram illustrating a leveled slot allocation method according to another embodiment in a more generalized form.

24 illustrates an example of a leveled slot allocation method using a DRAW according to an embodiment.

25 is a diagram illustrating another example of a leveled slot allocation method using DRAW according to an embodiment.

26 to 28 illustrate examples of a DRAW allocation method when a leveled slot allocation method is used, according to an embodiment.

29 illustrates an example of allocating frequency subbands for a relay according to an embodiment.

30 is a diagram for describing a case of using frequency selective transmission (FST) in a cluster when allocating a subband for a relay according to an embodiment.

31 illustrates an example of sharing RAW using different frequency subbands according to an embodiment.

32 illustrates an example of transmitting data using different frequency subbands according to an embodiment.

33 through 36 illustrate examples of a method of sharing RAW using different frequency subbands in a leveled slot allocation method using empty slots, according to an exemplary embodiment.

37 illustrates an example of a RAW sharing method when clusters are spatially separated according to an embodiment.

38 illustrates an example of a method of performing RAW sharing using a time domain according to an embodiment.

39 illustrates an example of allocating a plurality of frequency subbands according to an embodiment.

40 is a diagram illustrating an example of allocating a plurality of frequency subbands according to another embodiment.

FIG. 41 is a diagram illustrating an example of a format for Relay Resource Allocation IE of Table 3 according to an embodiment. FIG.

42 is a diagram illustrating an example of allocating resources for each time interval, according to an embodiment.

FIG. 43 illustrates an example of transmitting using a Relay Resource Allocation IE in a single frequency subband according to an embodiment.

44 illustrates another example of transmitting using a Relay Resource Allocation IE in a single frequency subband according to an embodiment.

45 is a diagram illustrating an example of transmitting using a Relay Resource Allocation IE in a multi-frequency subband according to an embodiment.

46 illustrates an example of allocating a relay transmission interval according to an embodiment.

47 is a diagram illustrating a format for frame request according to an embodiment.

48 is a diagram illustrating a format for a Frame Report according to an embodiment.

49 is a diagram illustrating an example of a format of a Measurement Request field according to an embodiment.

50 is a diagram illustrating an example of a format of a measurement report field according to an embodiment.

FIG. 51 is a diagram illustrating a method of measuring interference on a neighbor relay or a neighbor relay BSS using a frame request / response according to an embodiment.

52 is a diagram illustrating a configuration of an access point according to an embodiment.

53 is a diagram illustrating a configuration of a relay according to an embodiment.

54 is a diagram illustrating a configuration of a station according to an embodiment.

55 is a flowchart illustrating an operation of a resource allocation method performed by an access point according to an embodiment.

56 is a flowchart illustrating an operation of a resource allocation method performed by a relay, according to an embodiment.

57 is a flowchart illustrating an operation of a communication method performed by a station, according to an embodiment.

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 are shown in block diagram form, focusing on the essential 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). For clarity, the following description focuses on the IEEE 802.11 system, but the technical spirit of the present invention is not limited thereto.

When an access point (AP) transmits data (or a frame) to a station (STA), if there is an obstacle between the AP and the STA, the transmission efficiency may be reduced. In addition, when the STA transmits data to the AP, in general, since the STA has a lower transmission power than the AP, the STA may not properly transmit data to the AP. In order to solve such a problem and to further expand coverage when transmitting data between the AP and the STA, a relay is used.

In FIG. 1, since STA 1 and STA 3 are far from the AP, data transmission from STA 1 and STA 3 may not reach the AP, or a signal may be weakened. When forwarding data transmission from STA 1 and STA 3 using Relay1 and Relay2, these problems can be solved. The relay may be used not only for uplink transmission but also for downlink transmission from the AP to the STA.

In the case of the relay method using the slotted method in the WLAN system, efficient resource allocation such as efficient RAW operation, transmission slot allocation, transmission time interval allocation, and subband allocation are necessary to increase transmission efficiency. In order to increase transmission efficiency, RAW and transmission slots must be properly allocated so that a large number of STAs can transmit data without collision. In addition, a greater number of STAs must be able to simultaneously transmit data through a method such as sharing the same RAW or transmission slots or using different subbands during the same time interval.

The WLAN system may include an access point (AP), a relay, and a station. The scope of the basic service set (BSS) of the access point may be extended by the relay. The access point may be referred to as AP, Root AP, or RtAP, and the relay may be referred to as Relay AP, Relay STA, or R-AP. The station may be referred to as a STA and includes various communication terminals that may be connected to an access point or a relay.

The basic service set of the access point may be referred to as Root AP BSS. The relay can configure its basic service set, Relay BSS, and within the Relay BSS, the relay can act as an access point to the STA. Root AP BSS and Relay BSS may overlap each other. Root AP BSS indicates an area where the STA can maintain communication with the Root AP, and Relay BSS indicates an area where the STA can maintain communication with the Relay. Root AP BSS can extend communication area by Relay, and BSS of Root AP whose area is extended by Relay is called Extended BSS (Extended BSS). The extended BSS may include a relay BSS of a relay connected to the root BSS and the root AP.

Root AP can check the overall network status of the WLAN system. Root AP and relay can transmit a beacon including information about the allocated resources. The beacon transmitted by the Root AP may be referred to as Root Beacon, Rt-Beacon, or Root AP Beacon, and the beacon transmitted by the relay may be referred to as Relay Beacon, or R-Beacon. The STA may be connected to the root AP via a relay or may be directly connected to the root AP.

The AP may generate one BSS, and many STAs may be included in the BSS. In general, the STA directly transmits data to the AP as in STA M in FIG. 2, but may also exchange data with the AP via a relay for extending a transmission range. Several relays may be associated with one AP, and each relay may relay data transmitted and received from a plurality of STAs to the AP.

When using a relay to extend coverage, when the number of STAs in the BSS is large, the use of the slotted transmission method is required, and an efficient slot allocation method and operation considering the transmission involving the relay is required.

An example of a method of allocating a resource such as a RAW or a slot when transmitting data using a relay will be described.

The first method is to allocate RAW per transmission between STA and Relay (hereinafter referred to as 'bottom hop' transmission) and between Relay and AP (hereinafter referred to as 'top hop' transmission). 3 shows an example of such a method.

In FIG. 3, RAW1 is allocated for bottom hop transmission and RAW2 is allocated for top hop. In RAW1, STA1, STA2, STA3, etc. transmit data to Relay1 (R1), Relay2 (R2), etc., which are used by each. In RAW2, Relay1 (R1) and Relay2 (R2) send data to the AP. Here, it is also possible to perform uplink and downlink transmission in one RAW.

As another example of a method of allocating a resource such as a RAW or a slot when transmitting data using a relay, a method of allocating each RAW for each STA-Relay-AP (called 'parent tree') have.

In FIG. 4, RAW1 includes transmission between STA1, STA3, STA5 and Relay 1 using Relay 1 (R1), and transmission between Relay 1 and AP, and RAW2 includes STA2, STA4, STA6, STA8 using Relay 2 (R2). It includes the transmission between Relay 2 and Relay 2, and the transmission between Relay 2 and AP.

RAW and slot assignment information may be delivered via beacons. In this case, not only RAW and slot assignment information for the STA that does not go through the AP and the relay, but also RAW and slot assignment information for the relay, RAW and slot assignment information that allows the relay and the STA to be transmitted may be transmitted through the beacon. have.

Another example of a method of allocating resources such as RAW and slots when transmitting data using a relay is that a root beacon is transmitted only from a root AP within a BSS, but each relay also transmits its own beacon. In addition, there is a method in which a STA using a corresponding relay includes RAW and slot allocation information capable of transmitting uplink or downlink with a relay in a beacon transmitted by each relay.

That is, RAW and slot allocation for the transmission between the relay and the Root AP, the transmission between the Root AP and the STA that does not use the relay (that is, the transmission in which the Root AP directly transmits and receives data to the STA) is performed by the Root AP. Through the beacon (called Root Beacon) sent by the Root AP, information on RAW and slot allocation may be transmitted (this is called 'Level 0 slot allocation'). In the transmission between the relay and the STA (that is, bottom hop), the corresponding relay directly intervening in the transmission between the relay and the STA transmits the RAW and slot allocation information through the relay beacon by allocating RAW and slots (this is called 'Level 1 slot allocation'). ').

The relay can send and receive information with the Root AP for Level 1 slot assignment, which allows the Root AP to optimize its length of time (RAW or slot or time interval independent of the RAW / Slot of the Root AP). Can be assigned to The relay may directly allocate a RAW or a slot to be used for transmission between the relay and the STA based on information exchanged with the Root AP within a time interval allocated for the transmission between the relay and the STA.

The Root AP directs the Level 1 slot assignments, informs the Relay of the Level 1 slot assignments, and the Relay can only pass the Level 1 slot assignments via the beacon, but the RAW or slot to be used for transmission between the Relay and the STA. It is recommended that the relay be assigned directly. This is because the relay knows more information about STAs that are directly associated with it than the Root AP, so that the relay can more efficiently allocate Level 1 slots. That is, the Root AP allocates the transmission interval between the Relay and the STA, but does not directly perform detailed RAW / slot allocation in the transmission interval between the Relay and the STA, but does not directly perform detailed RAW / slot in the transmission interval between the Relay and the STA. Slot assignment is preferably delegated to the corresponding relay. This is hereinafter referred to as Leveled Slot (or RAW) allocation.

Due to the expansion of the BSS range using the relay, the STA connected to the relay may not receive the root beacon. If the relay beacon includes RAW / slot allocation information necessary for transmission between the relay and the STA, the corresponding STA may receive the relay beacon even without receiving the root beacon. In addition, since the relay beacon only needs to include RAW / slot allocation information necessary for transmission between the corresponding relay and the STA, the size of the relay beacon can be reduced.

Such a leveled slot (or RAW) allocation method is a method in which (A) the Root AP allocates resources such as a relay transmission interval and a relay transmission subband in the form of Delegated RAW (DRAW) at level 0 and allocates the DRAW interval to the relay. (B) Root AP may include a method for allocating resources to the relay independently of the RAW of the Root AP by using the resource allocation information, such as the relay transmission interval, the transmission band, other than the RAW format.

<(A) Root AP allocates resources such as relay transmission section and relay transmission subband in Delegated RAW (DRAW) form at level 0 and allocates DRAW section to relay (how to use DRAW)>

FIG. 5 shows an example of a method of allocating slots by dividing a level when a relay transmits a beacon (DRAW case).

At the top level 0, the Root AP assigns RAW and slots directly. RAW, slot for transmission between Root AP and Relay, and RAW, slot for STA that transmits and receives with AP directly without passing through Root AP and Relay are allocated. Since the relay collects data transmitted from several STAs through bottom hop transmission and transmits it to the AP, it is recommended to allocate more transmission time. To allocate more transmission time to a relay, you can assign multiple slots to a relay or a very long slot. In the example of FIG. 5, when uplink (UL) and downlink (DL) transmission are set to separate RAWs, it is also possible to perform uplink and downlink through one RAW. In addition, in the example of FIG. 5, uplink RAW and downlink RAW include transmission to a general STA, transmission to a relay, and the like. Only one transmission to a relay may be included in one RAW.

In Level 1 at the bottom, each relay can allocate a RAW and a slot for transmission with the STA using it. Each Relay can manage a Level 1 slot and can transmit slot allocation information for transmission between the Relay and the STA in a beacon transmitted by the Relay. For efficient RAW and slot allocation, the relay can exchange RAW and slot allocation information with the AP. The AP may use Level 1 RAW, slot allocation, and notify the Relay of the RAW and slot allocation information. However, it is more efficient for the Relay to perform RAW / slot allocation for the direct transmission between the Relay and the STA.

While the relay is transmitting and receiving data with the STA at Level 1, other STAs or relays using the same channel may not transmit or receive data with the AP.To prevent collision, the level 0 RAW and slot allocation information of the root AP is assigned to the root beacon. In addition, it can be transmitted by including information on the interval in which transmission occurs in Level 1 (called 'Empty slot' or 'Empty RAW' or 'Delegated RAW').

The AP may exchange information with the relay to determine an empty slot interval (or an empty RAW interval or a delegated RAW interval) at level 0. In order to set the empty slot interval (or empty RAW interval, or delegated RAW interval) in the uplink case, the relay needs to know the amount of data to be transmitted to the AP. Therefore, the AP receives UDI (Uplink Data Indication) information from the relay and is empty. Slot section can be set. Since the AP already knows the data amount for the STAs receiving the downlink data through the relay, in order to configure the empty slot interval in the downlink case, the AP considers the data amount for the STAs receiving the data through the relay. An empty slot section (or an empty RAW section, or a delegated RAW section) may be set to inform the relay of the set empty slot section.

In the above example, an empty slot section (or an empty RAW section and a delegated RAW section) for uplink and an empty slot section (or an empty RAW section and a delegated RAW section) for downlink are separated, The empty slot section for downlink can be set to one empty RAW (Delegated RAW), and the relay can allocate Uplink, Downlink, PS-Poll RAW, etc. at an appropriate ratio as needed within one Empty RAW (Delegated RAW). . In this case, there is an advantage that the relay can appropriately allocate slots according to the amount of uplink or downlink data with the STA connected thereto.

In case of relatively constant traffic volume and periodic transmission, such as sensor network and smart grid service, the AP allocates RAW and slot in a regular pattern when initial RAW and slot allocation, and RAW / slot You can also report allocation information. In this case, RAW, slot allocation may use PRAW (Periodic RAW). For example, if a RAW (Delegated RAW) used for transmission between a relay and a STA is allocated to a full beacon that is sometimes transmitted, and the relay allocation information has not changed since, relay RAW allocation information to a short beacon transmitted after the full beacon May not be specified separately.

The above example is an example of transmitting two hop relays via only one relay.In the case of multi-hops passing through multiple relays, the lower level may be set as much as the relay level, and the level may be extended based on the same method as above. .

In the example of FIG. 5, an empty slot for one relay is allocated in the RAW, but empty slots for several relays may be allocated in one RAW, and empty slots for each relay in one RAW as a whole. You can also assign

Relay beacons are transmitted by each relay, and relay beacons can be sent periodically. For example, after the beacon of the Root AP is transmitted, the relay beacon may be transmitted in the RAW or slot (the first empty slot for the corresponding Relay of level 0) allocated by the Root AP for the corresponding relay.

The relay can further increase transmission efficiency by aggregating data received from each STA using the self and transmitting the data to the Root AP. In addition, the Root AP aggregates and transmits data for several STAs to be transmitted through a Relay, and the Relay may increase transmission efficiency by dividing data received from the Root AP by each STA and transmitting the data to the corresponding STA. To this end, existing data collection techniques such as Aggregation-MAC Service Data Unit (A-MSDU) or Aggregation-MAC protocol Data Unit (A-MPDU) may be used.

In the slot allocation method as described above, if more STAs can share the same RAW and slot, the utilization of the slot is higher, which may further improve transmission efficiency. In particular, transmission efficiency may be further improved by allowing each STA to simultaneously transmit and receive data.

The number of RAWs that can be included in one Beacon section is limited, and this limited number of RAWs may be insufficient to perform transmission in each cluster. Here, the cluster is a unit including a relay and STAs using the relay.

Here's how to solve the limitations of RAW and make the most of RAW.

(1) assign multiple clusters to one RAW in the time domain

When there are not many STAs included in a cluster, several clusters may be allocated to one RAW. In this case, even if STAs of multiple clusters are allocated to one RAW, the number of STAs is not large, so there is little probability of collision, and data is sequentially sequentially in time according to the order in which STAs are allocated channels after contention. Can be sent. When transmission is not completed in a time interval allocated to a specific relay cluster, RAW allocated for simultaneous use in multiple clusters may be used to additionally transmit remaining data in a shared time interval.

(2) assigning multiple clusters to a single RAW in a spatial domain

If each cluster is far from each other, one RAW can be allocated to spatially separated clusters and data transfer can be performed at the same time.

For example, in FIG. 1, cluster 1 including relay 1 and cluster 2 including relay 2 may be allocated to the same RAW. In FIG. 1, STA1 and STA2 are spatially far from each other, and Uplink transmission in which STA1 transmits data to Relay 1 and Uplink transmission in which STA2 transmits data to Relay 2 may be simultaneously performed. Such simultaneous transmission may be easily applied to a transmission interval between each relay and an STA using each relay.

(3) assign multiple clusters to one RAW in the frequency domain

Clusters can be transmitted and received with the STA using different channels. As shown in FIG. 7, if the transmission between the relay 1 and the STAs in the cluster 1 including the relay 1 uses CH3 and CH4, the transmission between the relay 2 and the STAs in the cluster 2 including the relay 2 uses the CH1 and CH2. Data transfer can be performed at the same time, and these two clusters can be allocated to one RAW. 7 illustrates an example of sharing the same RAW using different channels according to an embodiment. This is useful when using relatively small bandwidths (BW), such as sensor networks, smart grids, and the like.

Such simultaneous transmission can be easily applied to a level 1 transmission period in which transmission between a relay and an STA using the relay occurs.

When simultaneous transmission is performed, communication between Relay 1 or Relay 2 and the AP may be performed using all of CH1-CH4. In addition, the relay may increase transmission efficiency by accumulating data received from each STA and transmitting the aggregated data using a wider channel.

As illustrated in FIG. 5, in the leveled slot allocation method of allocating slots by dividing levels, in order to utilize RAW and slots as efficiently as possible, information exchange between a relay and an AP and traffic information of STAs are required. In addition, when STAs continuously join, leave, or regroup STAs, the allocation of RAW and slots must be changed, which may act as an overhead.

In the RAW sharing method of (1)-(3) above, the Root AP uses the resource allocation information such as relay transmission interval and transmission frequency band to the relay independently of the RAW of the Root AP using separate resource allocation information. The same applies to the case of using the method of assigning a (method (B)).

(1) When using method (B) in connection with the method of allowing simultaneous transmission in the time domain, relays capable of transmitting in the cluster at the same time in the time domain may be allocated to the same transmission interval. The transmission interval allocated for simultaneous use in several clusters may be used to additionally transmit the remaining data in a shared time interval when transmission is not completed in a time interval allocated to a specific relay cluster.

(2) In the case of using method (B) in relation to the method of allowing simultaneous transmission in the space domain, transmission is performed at the same time for relays that can be simultaneously transmitted in a cluster because they are separated from each other in space. Just assign a time point. Transmissions in different clusters that are far enough apart from each other to be almost independent of each other may be simultaneously independent of each other. Transmission between spatially separated clusters does not necessarily need to align the transmission time intervals based on each other's transmission time intervals.

(3) A similar method to that in (B) may be applied to simultaneous transmission using different frequency subbands. You can configure different relays to use different subbands in the cluster. When the Root AP uses a subband different from the subbands used by each Relay, transmission between the Root AP and the STA or Relay directly connected to the Root AP may be performed simultaneously with the transmission in each relay cluster. If the subbands used for transmission performed by the Root AP and transmission in each relay cluster are different from each other, data can be independently independently transmitted simultaneously in the allocated subbands without having to adjust transmission intervals. In this case, time intervals should be allocated so that transmission is not performed simultaneously with a relay and an STA using the same subband.

(1), (2) and (3) above can be applied simultaneously. That is, by assigning different subbands, Root AP and multiple relays can transmit simultaneously in the cluster. Also, relays using the same subbands can transmit simultaneously if they are spaced apart so that they are not affected by each other. Even when the same subbands are used, if there are not many STAs belonging to one cluster, multiple clusters can be allocated to one RAW.

(4) Assign a plurality of clusters to one RAW by using offset information

This is a method of allocating a plurality of clusters (composed of one R-AP and a plurality of STAs) using an allocation offset (AO) value in one RAW period as shown in FIG. 8. 8 through 9 are diagrams illustrating an example of allocating a plurality of clusters to one RAW by using offset information, according to an exemplary embodiment.

8 and 9, if four RAW 0-RAW 3 are allocated within the beacon interval of the Rt-AP and four clusters are allocated to each RAW, the R-AP value is as follows. You can calculate your own allocation position using.

Information in the Rt-AP beacon frame

ASN (Allocation Sequence Number): 1 octet

Allocation Interval Order (AIO): 4 bit

R-AP parameters

Allocated RAW number: 1 octet

AO (Allocation Offset): 1 octet (0 <= AO <= 2 ^ (AIO + 1) -1)

-R-AP Location: current ASN% 2 ^ (AIO + 1) == AO

If the beacon Allocation Sequence Number (ASN) of the currently received Rt-AP is current ASN and the result value of "current ASN% 2 ^ (AIO + 1)" matches the AO value allocated from the Rt-AP, the current Beacon An interval interval may be determined as an interval allocated to a specific R-AP. In addition, the R-AP may identify the correct allocation position using the position value of the RAW allocated from the Rt-AP.

In FIG. 9, the R-AP having an Allocation identifier (AID) of 64 is its own allocation interval when ASN is "0, 4, 8, ..." when calculated using the allocation related parameter shown in FIG. Is 2176, the R-AP becomes its allocation interval when the ASN is "1, 5, 9, ...".

The R-AP of each cluster may be assigned a block AID during association with the Rt-AP. As shown in FIG. 10, a block AID may be allocated in a page unit, a block index unit, and a sub-block index unit using an AID structure. In this case, the first AID value of the allocated block AID may be the AID of the R-AP. have. The remaining AID values except for the AID of the R-AP may allocate the AIDs within the predetermined range to the STAs when the STAs in the cluster request an association. By allocating the AID for each cluster (or level in the 2-hop network), the AP can easily allocate the AID and manage it efficiently. In the example of FIG. 10, each RAW is allocated in units of Page IDs, and each cluster is allocated in blocks of index units. Accordingly, the R-AP of each cluster may manage a total of 64 block AIDs including its own AID. This is a structure in which one R-AP can accommodate up to 63 STAs.

11 illustrates an example of beacon allocation positions of R-APs when RAW is allocated in cluster (or treelevel) units. Each RAW starts with the beacon of the allocated R-AP and can consist of the same number of slots. With this configuration, the beacon allocation position of the R-AP can be automatically determined, and the length and position information of the RAW can be determined by the Root AP (Rt-AP).

Referring to FIG. 12, slots for STAs are allocated in a RAW duration.

In FIG. 12, the R1 (R-AP) transmits allocation information to an STA requesting association to the STA, so that the STA may simply receive slot allocation without performing a separate allocation procedure. The allocation information delivered by the R1 (R-AP) to the STA may include the following information.

Information in the R-AP beacon frame

-Slot length information, total number of slots

STA Slot Allocation bitmap (0: empty slot, 1: allocation slot)

STA slot allocation info: allocated to R-AP during association

Allocated slot number

The STA may transmit and receive data with the R-AP in the slot period allocated to the STA. If there is downlink data (data transmitted from the R-AP to the STA), the R-AP may transmit data using an acknowledgment frame or TIM (Traffic Indication Map) information.

If the network configuration changes relatively little, it may be more efficient for the AP to allocate RAW and slots to reduce overhead. An example of a simplified leveled slot allocation method with less overhead for such a case will be described.

13 illustrates an example of a RAW for Simplified leveled slot allocation. The AP may determine the RAW structure based on the total number of STAs and the relay number at the beginning of BSS generation. Each RAW may have the same length, and the information about the RAW structure may be composed of the following fields in the beacon frame of the Rt-AP.

-Length of RAW

-Total number of RAW

RAW allocation bitmap (0: empty RAW, 1: allocation RAW)

RAW type information (R-AP RAW, Rt-AP RAW, common RAW)

RAW can be classified by RAW type. The R-AP RAW indicates a section in which only the R-AP and the STA in the cluster can exclusively transmit and receive data. Rt-AP RAW is a section for communication with STAs directly managed by Rt-AP itself, and a common RAW is a section in which all nodes can be used contention-based.

RAWs for a plurality of relays may be allocated to a beacon interval of a root AP. One or several RAWs can be assigned to a relay. For example, when transmitting STA / Relay / Root AP, PS-Poll RAW for resource allocation of UL and DL, DL RAW or UL RAW for transmission between STA and Relay, DL / UL RAW, transmission between Root AP and Relay DL RAW or UL RAW or DL / UL RAW may be allocated by various combinations as necessary. In addition, when transmission periods of STAs connected to a relay are different, RAWs for transmission between a plurality of relays / STAs may be allocated within one relay beacon interval.

In addition, a transmission interval for transmission from the root AP to another relay or another STA may be allocated together in a relay RAW group for a specific relay.

Since the relay is used to extend the transmission range, STAs connected to the relay may not receive the beacon of the root AP and thus may not acquire RAW information allocated by the root AP. Accordingly, after each relay receives the root beacon from the root AP, the relay beacon may transmit the RAW allocation information related to the root beacon and the slot allocation information necessary for level 1 transmission to the STAs connected thereto. The relay does not transfer the information contained in the root beacon as it is, and may extract only information necessary for itself from the information included in the root beacon. Since the relay transmits the extracted information including only additional slot allocation information for level 1 transmission, the relay beacon transmitted by the relay to the STA may be smaller in size than the root beacon.

The Root AP may include RAW allocation information for level 0 transmission (transmission between the Root AP and the Relay and between the Root AP and the STA directly connected to the Root AP) in the Root beacon.

The relay may receive a Root AP beacon from the Root AP and identify RAW allocation information of the Root AP from the Root AP beacon. Thereafter, the relay may include RAW allocation information necessary for the STA connected to the relay in its relay beacon and transmit the same to the STA. For example, the RAW allocation information required for the STA may include RAW and slot allocation information for transmission between the relay and the STA, section information in which transmission between the Root AP and the relay occurs. The STA connected to the relay may receive the relay beacon and determine when to transmit data based on the received relay beacon.

In FIG. 15, a relay RAW group represents RAWs allocated for one relay. In the embodiment of FIG. 15, a beacon of each relay is transmitted at the time when the first RAW of the corresponding relay RAW group starts. The relay allocates the first RAW immediately after each relay beacon is transmitted to the PS-Poll RAW, and the STA can transmit the PS-Poll and the Unique Device Identifier (UDI) to the connected relay. In order to optimize UL RAW and DL RAW for transmission between the Root AP and the Relay and transmission between the Relay and the STA, the Relay may transmit PS-Poll and UDI to the Root AP.

In the embodiment of FIG. 16, the time point for transmitting the relay beacon in FIG. 15 is changed to immediately after the root AP beacon. The beacons of all relays allocated within one beacon interval are sequentially transmitted immediately after the Root AP Beacon is transmitted, and the first RAW to be started may be allocated as PS-Poll intervals for several relays.

In the embodiment of FIG. 15, a PS-Poll section is allocated to each Relay Group RAW, but in the embodiment of FIG. 16, only one PS-Poll RAW is used, and PS-Poll and UDI for all relay transmissions in this PS-Poll RAW are used. Can be transmitted. In this case, the PS-Poll section does not need to be allocated to each Relay Group RAW.

This reduces the chance of wasting RAW than setting PS-Poll RAW as one and allocating PS-Poll RAW for each relay separately. In addition, the STA searching for a relay to be connected may select an optimal relay within a short time since beacons for each relay are transmitted in sequence immediately after the root AP beacon is transmitted.

The method of transmitting the relay beacon described in the above example, that is, (1) the time of transmitting the relay beacon is distributed, and the method of transmitting the relay beacon at the RAW start time assigned to each relay, and (2) after the Root AP beacon The relay beacon of each relay is transmitted, and a method in which each relay RAW may not be started immediately after the relay beacon may be selectively applied in other embodiments. The distributed relay beacon transmission method or the centralized relay beacon transmission method can be applied to all of the embodiments of (A) a method using DRAW and (B) a resource allocation method using resource allocation information.

In the method of distributing relay beacons, the relay RAW may not come immediately after the relay beacon, or relay RAW may be allocated when the relay beacon is separated from the relay beacon.

Even in the method of centrally relaying relay beacons, relay beacons that are simultaneously transmitted may safely transmit relay beacons by allocating a relay beacon transmission RAW separately from the root AP beacon.

Referring to FIG. 17, allocation of all RAWs may be performed by the Root AP, and allocation information of all RAWs may be provided through a root beacon. The slot for the RAW corresponding to the level 0 transmission may be allocated by the root AP. RAW for level 1 transmission is allocated to an empty RAW (Delegated RAW) or an empty slot (delegated slot) by the Root AP, and no specific slot allocation is performed. In an empty RAW (Delegated RAW) or an empty slot (delegated slot) of a root beacon, a duration for transmission between the relay and the STA is displayed, and based on this, another STA transmits data to the transmission interval between the relay and the STA and collides with the other. The occurrence of collision can be prevented. The slot for the level 1 transmission, that is, the transmission between the relay and the STA may be allocated by the relay, and the information on the allocated slot may be included in the relay beacon.

Slot allocation information of RAW for level 0 transmission in the relay beacon may be omitted, and RAW for level 0 transmission in the relay beacon may be indicated as an empty RAW or an empty slot. In an empty RAW or empty slot of a relay beacon, only a transmission duration between a relay and an AP may be displayed, which prevents an STA connected to the relay from transmitting data while the relay is transmitted between the AP and the relay. The STA connected to the relay receives only the RAW allocation information of the relay beacon and does not need to receive the root beacon.

In FIG. 17, the RAW for relay transmission may be configured as a DL RAW in which data is transmitted from a Root AP to a Relay, a DL & UL RAW between a Relay and a STA, and a UL RAW in which data is transmitted from the Relay to the Root AP. DL & UL RAW refers to RAW, which allows both DL and UL transmission in one RAW. The RAW configuration shown in FIG. 17 is only one example, and other types of combinations are possible.

DL RAW, in which data is transmitted from the Root AP to Relay, and UL RAW, in which data is transmitted from the Relay to Root AP, can be allocated up to the slot. The Root AP can set the DL & UL RAW between the Relay and the STA to empty RAW (Delegated RAW), and can include and transmit the RAW allocation information on the DL & UL RAW between the Relay and the STA in the Root AP beacon.

After the relay receives the Root AP beacon, the relay may allocate a slot for DL & UL RAW between the Relay and the STA configured by the Root AP to empty RAW (Delegated RAW). Relay can be set to DL RAW, which transmits data from Root AP to Relay, and UL RAW, which transmits data from Relay to Root AP, to empty RAW, which can be included in Relay beacon for transmission.

Relay transmits DL or UL or DL based on slot allocation information of Root AP in DL RAW, which transmits data from Root AP to Relay and UL RAW, which transmits data from Relay to Root AP, identified through Root AP beacon Can be performed.

The STA connected to the relay may perform UL and DL transmission with the relay based on slot information allocated in DL & UL RAW between the relay identified through the relay beacon and the STA.

RAW after Root AP beacon and Relay beacon is transmitted is assigned as PS-Poll RAW, STA transmits PS-Poll and UDI to Relay, Relay transmits PS-Poll and UDI to Root AP UL RAW and DL RAW may be optimized for transmission between the RSs and transmissions between the relay and the STA.

In the embodiment of FIG. 18, each relay RAW group may be configured with a combination of PS-Poll RAW, DL RAW, UL RAW, or UL RAW / DL RAW.

Immediately after transmission of the root beacon and the relay beacon, each STA may transmit the PS-Poll and the UDI to the relay. After receiving the PS-Poll and UDI, the relay may identify the UL data amount and resource allocation requirement of the STA and then transmit the PS-Poll and UDI to the Root AP based on the identified UL data amount and the resource allocation requirement. .

A period during which the STA transmits PS-Poll and UDI to the relay may be protected by an empty slot at level 0, and a period during which the relay transmits PS-Poll and UDI to the AP may be protected by being set as an empty slot at level 1.

After receiving the PS-Poll and UDI, the Root AP can adjust slot allocation necessary for UL and DL of STA and Relay. The Root AP can refine the DL slot allocation for level 0 and level 1 based on the PS-Poll information at the starting point of RAW2. The Root AP may include slot allocation information for level 0, and may transmit slot allocation information at level 0 by transmitting a DL allocation frame in which a level 1 transmission interval is allocated to an empty slot. After receiving the slot allocation information from the Root AP, the relay may display the slot allocation information at level 0 as an empty slot without including slot allocation information at level 0. The relay may allocate a slot for a section allocated by the Root AP to an empty slot at level 0 and transmit slot allocation information through a DL allocation frame at level 1.

The STA may receive the DL allocation information and identify a slot allocated to the STA based on the DL allocation information.

The Root AP can adjust slot allocation in level 0 and level 1 using UDI information and UL allocation frame similarly to the above for UL RAW.

Empty slot may be indicated in the RPS IE or DL or UL allocation frame included in the beacon. Root Beacon's RPS IE can indicate which relays are allowed to the Relay RAW Group.

19 shows an example of allocating DL RAW and UL RAW to one RAW (UL / DL RAW) without assigning them to separate RAWs. The Root AP may transmit a UL / DL allocation frame for DL and UL slot allocation adjustment based on the PS-Poll and UDI received through the STA and the Relay. In this case, since the DL RAW and the UL RAW are not separated, the Root AP can flexibly adjust and allocate the UL transmission section and the DL transmission section in one RAW.

Referring to FIG. 20, each relay RAW group may be configured with a combination of PS-Poll RAW, DL RAW, UL RAW, or UL / DL RAW, and an empty slot may be allocated to one separate RAW.

Immediately after transmission of the root beacon and relay beacon, each STA may transmit PS-Poll and UDI to the relay. After receiving the PS-Poll and the UDI, the relay may identify the UL data amount and the resource allocation requirement of the STA and then transmit the PS-Poll and the UDI to the Root AP based on the UL data amount and the resource allocation requirement.

The interval during which the STA transmits PS-Poll and UDI to the relay can be protected with empty RAW at level 0, and the interval during which the relay transmits PS-Poll and UDI to the AP can be protected by being set to empty RAW at level 1. have.

After receiving the PS-Poll and UDI, the Root AP can fine tune the slot allocation required for the UL and DL of the relay. The Root AP can adjust the DL slot allocation for level 0 based on the PS-Poll information at the starting point of RAW2. The Root AP may inform the adjusted slot allocation information at level 0 by transmitting a DL allocation frame including slot allocation information for level 0. FIG.

The relay can adjust the DL slot allocation for level 1 based on the PS-Poll information received from the STA at the starting point of the RAW 2 '. The relay may inform the adjusted slot allocation information at level 1 by transmitting a DL allocation frame including slot allocation information for level 1.

The relay may finely adjust the UL slot allocation for level 1 based on the UDI information received from the STA at the RAW 3 'start point. The relay may inform the adjusted slot allocation information at level 1 by transmitting a UL allocation frame including slot allocation information for level 1.

The Root AP can finely adjust the UL slot allocation for level 0 based on the UDI information received from the relay at the RAW 3 start point. The Root AP may inform the adjusted slot allocation information at level 0 by transmitting a UL allocation frame including slot allocation information for level 0. FIG.

Empty RAW may be displayed in the RPS IE (RAW Parameter Set Information Elemnet) included in the beacon. Root Beacon's RPS IE can indicate which relays are allowed to the Relay RAW Group.

FIG. 21 illustrates an embodiment in which a transmission period between a relay and a STA is allocated to one DL / UL RAW without dividing the transmission interval between the relay and the STA into DL RAW and UL RAW in FIG. 20. In this case, the DL allocation frame for the DL RAW and the UL allocation frame for the UL RAW are not separated from each other, and the DL & UL allocation frame including the UL slot and DL slot information adjusted based on the PS-Poll and the UDI information of the STA is not included. Can be sent from the RAW2 'start point.

By setting the DL / UL RAW as one RAW, UL slots and DL slots between the STA and the relay can be flexibly allocated, thereby enabling RAW to be more efficiently utilized. That is, the transmission in the cluster where the transmission between the relay and the STA is performed can be performed more efficiently.

In the embodiment of FIG. 22, the Root AP may allocate one RAW to one Relay transmission and may include and transmit information on RAW allocation in the Root AP beacon.

Each Relay can divide one Relay RAW allocated to itself into sub RAW and transmit sub RAW allocation information, which is allocation information about sub RAW, in relay beacon.

The STA and the root AP connected to the relay may determine when transmission between the STA and the relay and transmission between the relay and the AP are performed based on the sub RAW allocation information of the relay beacon.

The embodiment of FIG. 23 is similar to the embodiment of FIG. 17, but the transmission interval between the root AP and the relay is not dependent on the transmission interval between the relay and the STA, and may be allocated to any interval in a form similar to the transmission between the general AP and the STA. Can be. 23 differs from the embodiments related to FIG. 17 in that relay beacons are transmitted at a start time or before a start of Delegated RAW (empty RAW at level 0) used for transmission between a relay and a STA.

RAW and slot in the transmission interval between the Root AP and the relay, or RAW and slot in the transmission interval between the STA and directly connected to the Root AP may be allocated by the Root AP. RAW and slot allocation information may be included in the Root AP beacon and transmitted. At this time, the transmission interval between the root AP and the relay may be assigned to any interval in a form similar to the transmission between the general AP and the STA, without being dependent on the transmission interval between the relay and the STA. The transmission period between the root AP and the relay and the transmission period between the root AP and the STA directly connected to the root AP may be allocated together in one RAW or may be allocated in a separate RAW.

Root AP can be assigned by indicating the transmission interval between the relay and the STA as Delegated RAW (Empty RAW at level 0), and specific RAW / Slot assignment can be delegated to the relay. Root Beacon may not include level 1 RAW / slot allocation information.

The Root AP may allocate one DRAW (Delegated RAW) or multiple DRAWs for transmission between the relay and the STA.

Based on the DRAW, relays and transmission allowance intervals that allow transmission in the corresponding DRAW may be identified. In DRAW, only data transmission between a relay specified as being allowed to be transmitted and STAs connected to the corresponding relay may be allowed in principle. As a result, collision between STAs connected to different relays due to an extended service range in a basic service set (BSS) can be effectively prevented.

For the efficiency of medium use, it is possible to prohibit transmission of the STA belonging to the root BSS only for the section in which the Root AP explicitly sets Empty RAW in the DRAW section, and allows the transmission for other sections. have. In this case, the following two methods can be used to protect the relay transmission.

<1. How to Protect Resources Assigned to Other Relays>

The Root AP determines the spatial separation between the Root BSS and the other Relay BSS, and if it is not sufficiently separated, sets another Relay transmission section (DRAW section) to Empty RAW (or AP PM RAW) and is connected to the STA. Can prohibit data transmission. Even in the DRAW interval, the STA may transmit data in the interval not explicitly set to Empty RAW. Or, the Root AP does not prohibit data transmission of all STAs in the Root BSS for another Relay transmission interval (that is, a DRAW interval), and prohibits transmission only for a specific STA that is heavily interrupted by other Relay BSS among the STAs in the Root BSS. You can also In this case, use of a modified Empty RAW (or modified AP PM RAW) that may indicate an STA that is explicitly prohibited from transmission, or a method of excluding a STA forbidden from transmission interval allocation may be used. Can be.

How the Root AP identifies whether a particular STA in the Root BSS is interfered with by another Relay BSS may be determined by using the Root AP using a method of determining a spatial separation between (BB) relays (to be described later). May receive the interference information of the STA, or the STA of the Root BSS that directly interferes with information on another Relay BSS or another STA that the STA interferes with may notify the Root AP directly.

In order to prevent a collision caused by an STA belonging to a relay BSS transmitting in a transmission section of another relay BSS using the same channel, the relay AP discards the transmission section of another relay BSS in an empty RAW (or AP PM RAW). ) Can be set to prohibit transmission. Data transmission of the STA may be allowed in a section that is not set to Empty RAW.

Relay BSS periodically determines whether it is spatially separated from other Relay BSS, and if it is determined that it is not sufficiently separated from each other, it sets the other Relay transmission interval to Empty RAW (or AP PM RAW) to stop data transmission of STAs connected to it. Can be prohibited.

Alternatively, the Relay BSS does not prohibit data transmission of all STAs in the Relay BSS with respect to another Relay transmission interval, and may only prohibit data transmission of a specific STA that is frequently interfered with other Relay BSS among the STAs in the Relay BSS. In this case, a modified Empty RAW (or modified AP PM RAW) that may indicate a STA that is prohibited from transmission, or a RAW allocation method that excludes the STA that is prohibited from transmission may be used.

The relay AP knows whether a particular STA in the relay BSS is interfered by another relay BSS (or a root BSS) by using a method of determining a spatial separation between (BB) relays. Can be used to receive the interference information, or the STA of the relay BSS receiving the interference information on another relay BSS or another STA that interferes with the STA directly to the relay AP.

If there is a frame to be urgently transmitted from the Root AP, transmission in the DRAW period may be exceptionally allowed. In addition, in the level 1 transmission, the STA may not detect a transmission in another relay BSS in which transmission is in progress, or (2) another relay in progress, even if it is a time interval not allocated to the relay to which the STA belongs. When receiving a beacon of, transmission may be allowed exceptionally for a section in which RAW is not allocated within a section allocated for transmission in the corresponding relay BSS.

Alternatively, STAs belonging to the Root AP and STAs belonging to the Relay may be allowed to transmit through contention, such as transmission in an existing OBSS environment, even in a section in which transmissions for their APs are not allocated. However, when transmitting data in a section not allocated to its BSS, the collision probability is high, so the STA preferably performs the RTS / CTS before transmitting the data.

The relay or the root AP may explicitly prohibit transmission of STAs connected to the self by setting an empty RAW period in which a collision or contention is expected to be severe among transmission periods not allocated to the relay or root AP. In addition, the relayAP may prohibit the STA from transmitting to the relay in the section in which the transmission between the relay and the root AP occurs by setting the empty RAW period between the relay and the root AP.

<2. Relay How to Protect Resources Assigned to It>

The relay can request the root AP for protection of resources allocated to it. In response to a Relay's request, the Root AP may explicitly specify certain other Relay BSSs or some STAs of certain other BSSs for the resources allocated to that Relay (e.g., the transmission interval or the interval allocated by the Root AP to DRAW). (Including STA of Root BSS) may be prohibited.

For example, a relay is severely interrupted by transmissions of specific STAs (or STAs of a root BSS) belonging to another Relay BSS or another Relay BSS, so that all other Relay BSSs or some STAs of other Relay BSSs are transmitted in the transmission interval assigned to the relay. If the user wants to prohibit the transmission of the data, that is, to be protected, the relay can request the Root AP to protect the resources allocated to the relay. When the relay requests protection from the root AP, the relay may transmit to the root AP a list of other relay BSSs or specific STAs of the relay BSS that are severely interfering.

The relay AP may inform the Root AP of Relay BSS or specific STAs that interfere with it. In addition, each STA in the Relay BSS may also inform other relay BSSs or specific STAs that have severe interference to the relay AP, and the relay AP may transmit information of other relay BSSs and STAs that interfere with the root AP. In this case, STAs may not need a measurement function in 802.11k or the like.

When the STAs have a measurement function in 802.11k, the relay AP requests a measurement from the STA and checks other relay BSSs and STAs that interfere with the STA connected to it based on the measurement result from each STA. Can be determined. The relay AP may notify the Root AP of other relay BSSs and STAs determined.

When the Root AP receives a resource protection request from a relay, the Root AP may indicate specific STAs of a Relay BSS or a Relay BSS that should not be transmitted to the DRAW for a Relay that has made a resource protection request.

The relay does not transmit in the transmission interval of the other relay BSS if it is included in the relay prohibited list of the DRAW allocated to the other relay BSS. The relay may protect the resources of the relay requesting resource protection by allocating empty RAW (or AP PM RAW) to the STA belonging to it and explicitly prohibiting transmission of the STA. If it is indicated in the DRAW to prohibit transmission to some STAs of the Relay BSS instead of the entire Relay BSS, the Relay may prohibit transmission of only a specific STA designated for the corresponding Relay BSS transmission interval.

In order to prohibit only transmission of a specific STA in the relay BSS, (1) a method of modifying and using an AP PM or empty RAW or (2) a method of using RAW allocation may be used. In the case of the method (1), the relay includes the (partial) AID list of the STA to prohibit transmission for a certain period in the AP PM RAW or Empty RAW, and only the STA to be prohibited in the AP PM RAW or Empty RAW interval is explicitly stated. The transmission may be prevented and the remaining STAs may allow transmission through contention. In the case of the method (2), the relay may not assign an STA (that is, an STA interfering with another relay) to RAW to prevent the transmission of the STA to prohibit the transmission.

When the relay requests that the specific STA in the Root BSS receives interference, the corresponding STA may not be included in the DRAW and the Root AP may prohibit transmission of the STA during the Relay transmission period.

In the case of using the DRAW, a strictly disallow bit, a relay AP, and a STA list may be displayed by adding a field to the DRAW.

If all of the information of the strictly disallowed STA in the DRAW as described above, the size of the beacon may be too large. As another method, the Root AP collects information on the relay AP and STA to be strictly disallowed and received from the relay, and broadcasts a message including the relay AP and STA information to strictl disallow for each Relay BSS to each Relay, or There is a method of delivering using a separate frame in unicast. A relay that receives a message containing information on the relay AP and STA to be strictly disallowed checks whether or not it is strict disallowed by itself or the STA connected to it in the transmission interval of another relay, and when it is confirmed that the relay is disallowed, Do not transmit in the transmission section.

DRAW can be allocated periodically, in which case PRAW (Periodic RAW) can be used. The use of PRAW may be appropriate because the relay beacon must be sent periodically before or at the beginning of the DRAW.

The relay beacon transmission period may be determined by the relay and the root AP negotiating with each other when the relay is connected to the root AP, and the relay beacon transmission period may be equal to the Root AP beacon interval or may be a multiple of the Root AP beacon interval.

After receiving the relay beacon, the relay can check whether the DRAW is assigned to itself. When the DRAW is allocated to itself, the relay may allocate RAW / slot for transmission with STAs connected to the device within a duration range allocated to the DRAW. The relay may know whether the STAs connected to the base station have DL data based on the TIM of the Root Beacon, and may schedule the DL for the STA when receiving the DL data from the Root AP. When the relay transmits the relay beacon to the STA, the relay may inform the STA through the TIM of the relay beacon of the information on which STA has DL data and the RAW / slot allocation information. The STA connected to the relay does not need to check the root beacon. It is sufficient to check only the beacon of the connected relay.

The relay can receive the PS-Poll from the STA by allowing the PS-Poll RAW to be allocated immediately after transmitting the relay beacon. In addition, the relay may receive detailed UDI information from the STA and transmit a resource allocation frame to fine-adjust the initial RAW / slot allocation allocated by the relay during relay beacon transmission.

That is, the relay may properly allocate and utilize RAW / slot so that the DRAW allocated to the relay is suitable for transmission with the STA connected to the relay. In this case, the same standard as that of the general RAW / slot allocation may be used for the RAW / slot allocation method in the DRAW.

When the STA transmits data in a section other than the DRAW in which the Root AP guarantees transmission between the Relay and the STA, a collision between transmission of the STA connected to another relay or transmission between the Relay and the Root AP may occur. The relay can prevent a collision in the BSS by preventing STAs connected to the transmission from a period other than the DRAW period allocated to the relay. In this case, transmission may be allowed only in a section in which the transmission of the STA is explicitly allocated in the RAW / slot allocation of the DRAW, and the STA may be informed not to transmit in the remaining sections. According to an example, it may indicate whether to prohibit transmission except for the DRAW period in which transmission of the STA is allowed using 1 bit.

Alternatively, the STAs connected to the relay among the sections other than the DRAW may explicitly allocate a section that should not be transmitted to RAW and prohibit transmission through the RAW. This RAW is called empty RAW at level 1. Although all sections other than the DRAW may be allocated as empty RAW, only sections in which the STA should never transmit in the non-DRAW section may be set as empty RAW. According to an example, one bit indicating whether empty RAW (transfer prohibited RAW) can be allocated to RAW, and a start time and a period not to be transmitted can be signaled by a start time, duration, etc. of RAW.

In a period where transmission to an empty RAW is not explicitly prohibited, a STA belonging to a relay cannot detect a transmission in another relay BSS in progress or when receiving a beacon of the corresponding relay, Transmission may be exceptionally performed for a section in which RAW is not allocated within a section allocated for transmission.

As another example, STAs belonging to a relay may transmit through contention as in transmission in an existing OBSS environment even in a period where transmission for their AP is not allocated. In this case, since the probability of collision is high when transmitting in a section not allocated to its BSS, it is recommended that the STA perform RTS / CTS before data transmission.

Relay or Root AP can explicitly prohibit transmission of STAs connected to it by setting Empty RAW in a section where collision or contention is expected to be severe among transmission sections not assigned to it.

In addition, the relay AP may prohibit the STA in the relay from transmitting to the relay by allocating an interval in which the transmission between the relay and the root AP occurs to the empty RAW.

In a section in which transmission of an STA connected to a relay is prohibited, the relay may sleep for power saving in a section in which no transmission is performed between the relay and the root AP. In addition, the Root AP may sleep for power saving in a section in which there is no transmission with a relay or STA directly connected to itself in the DRAW section. The relay must be awake during its assigned DRAW interval.

FIG. 24 illustrates a case in which a DRAW at level 0 is disposed adjacent to DL RAW and UL RAW, and the DL transmission to the Root AP Relay STA and the transmission to the STA Relay Root AP are sequentially performed. When arranging RAW in this way, when the STA has DL transmission from the Root AP to the corresponding STA, the STA may receive the DL data and immediately transmit the response UL data to the Root AP, thereby reducing the transmission delay.

After receiving the relay beacon, the relay may determine whether there is data transmitted by itself based on the TIM, and transmit the PS-Poll according to the determination result. The Root AP can optimize the RAW / slot allocation by receiving the PS-Poll from the Relay and transmitting a resource allocation frame 2410.

The relay may receive PS-Poll and UDI from the STA after the relay beacon transmission, and may optimize UL RAW and DL RAW of the relay transmission section corresponding to the DRAW section allocated by the relay.

Relay transmits UL data size received from STA to Root AP before transmitting UL data to Root AP. Root AP may optimize UL RAW at level 0 using resource allocation frames. have.

FIG. 25 illustrates an embodiment in which transmission is performed in a different order from that shown in FIG. 24. Referring to FIG. 25, after the STA receives DL data from the Root AP via a Relay, when the STA transmits UL data to the Relay, the Relay does not immediately transmit the UL data to the Root AP, and when the next Root Beacon is transmitted. The UL data may be transmitted in the allocated UL RAW, or may be transmitted in UL / DL RAW. In this case, the relay stores UL data without directly transmitting it to the Root AP. When the next Root Beacon is received and the Relay transmits the PS-Poll to the Root AP, the UL data size received from the STA in the previous beacon section is stored. You can notify Root AP through UDI. Through this, the Root AP can optimize the UL / DL RAW for the relay by transmitting one PS-Poll RAW and one resource allocation frame.

The relay may transmit the UDI to the root AP before the next root beacon transmission time. Root AP can know UL data size from Relay before Root Beacon transmission through UDI received from Relay so that UL RAW can be allocated to optimal length from Root Beacon transmission from the beginning. In this case, a delay may occur when the UL transmission from the STA is delivered to the final destination, and a memory for storing UL data is further needed.

26 to 28 illustrate examples of a DRAW allocation method in the case of using the leveled slot allocation method of FIG. 23, and are examples of a DRAW allocation method when a relay beacon period is different from a root beacon period.

The relay beacon period does not have to be the same as the root beacon period, and the relay can negotiate the relay beacon period when transmitting association request / response frame with the root AP when connecting to the root AP.

In addition, since each STA connected to a relay may have a different wake up period, the relay needs to allocate RAW more frequently for a specific STA group even when using the same relay beacon interval. . The Root AP should allocate a DRAW to periodically guarantee transmission for the STA group. The relay may transmit information such as the type of the STA, the traffic type of the STA, or the wake up / listen interval to the Root AP together with the AID or partial AID information of the STA connected to the Root AP. Root AP can allocate the DRAW based on the information received from the relay. The relay may notify the Root AP when a service type of the connected STA is changed or when a new STA is connected.

FIG. 26 illustrates a case in which a Root Beacon Interval is 3 and a Relay Beacon Interval is 6, and one DRAW for a specific relay is allocated to each Root AP Beacon interval. The relay allocates RAW / Slots for STAs based on the DRAW interval allocated to the relay.

According to another embodiment, when the DRAW is periodically allocated, the allocation information of the RAW / Slot is not transmitted for every beacon using the PRAW, the allocation information is transmitted only in the full beacon, and the multiple of the Beacon interval (short beacon interval), etc. You can also specify the transmission period of the full beacon.

When the allocated RAW in the DRAW period is periodically repeated, the relay may inform the relay beacon of PRAW in the relay beacon.

In FIG. 26, two DRAWs are allocated to a relay beacon interval for a relay. The relay may allocate the transmission interval of the STAs that wake up more frequently among the STAs connected to the DL / UL transmission to both DRAWs, and the transmission intervals of the less wakeful STAs to one DRAW. . For example, the relay may allocate the transmission interval of the STA such that the transmission period of the STA that frequently wakes up is 3 and the transmission period of the STA that wakes up less frequently is 6.

FIG. 27 illustrates a case where a Root Beacon Interval is 6, a Relay Beacon Interval is 12, and two DRAWs for a specific relay are allocated to each Root Beacon interval. This is suitable when the transmission of the STA connected to the relay occurs more frequently than the root beacon interval period. DRAW1 and DRAW2 are allocated for a specific relay, and STA can transmit in shorter period than Interval of Root AP Beacon.

FIG. 28 illustrates a case in which [DRAWs 1 and 2 of FIG. 27 are allocated to different relays, respectively, Root Beacon Interval is 6, each Relay Beacon Interval is 6, and each relay is allocated a DRAW at a cycle 6. FIG.

29 illustrates an example of allocating frequency subbands for a relay according to an embodiment. More specifically, FIG. 29 illustrates a specific embodiment of RAW sharing between a relay cluster, which is a group of relays and STAs connected to the relay.

If transmission between relay clusters can be separated, an interval allocated to empty slot or empty RAW at level 0 of the leveled slot allocation method may be shared between relay clusters, and simultaneous transmission between clusters may be possible. For example, (1) using different frequency subbands, (2) clusters are spatially separated, or the number of STAs belonging to one relay group is small and STAs are assigned to one RAW in time. RAW sharing is possible if you can transfer sequentially.

<1. How to perform RAW sharing using different frequency subbands>

Root AP can allocate a channel to be used for transmission between each relay and STA. The relay can inform the Root AP of its preferred channel range when connecting to the Root AP, and the Root AP can use the channel to be used for transmission between Relay and STA based on the channel occupancy status of other relays in the BSS. Can be assigned.

A primary channel used for transmission between a root AP and a relay may always be the same. The relay may use a channel different from the primary channel of the root AP for transmission with the STA connected thereto.

Root AP can allocate relays that do not overlap channels used in the cluster to the same DRAW when DRAW is allocated so that simultaneous transmission can occur between clusters with different frequency subbands. have. 29 shows an example of subband allocation for allocating relays in which channels do not overlap to the same DRAW.

The Root AP can inform the Root Beacon's RPS IE or a similar new IE of the identification information of the relay that is allowed to transmit during DRAW and the transmission allowance period. For example, the identification information of the relay may include AID, partial AID, or partial basic service set identification (BSSID) of the relay. The Root AP may transmit information about the available channel and the relay to STAs that want to newly connect to the Root AP or Relay. Root AP can transmit to the Beacon including the channel allocation bitmap for each channel to inform the availability of the channel. If a beacon is transmitted with a relay allocation bitmap for each channel, the STA to attempt to connect may identify which relay is allocated to each channel based on the root beacon. The STA may perform scanning by directly moving to the primary channel where the relay exists, and may identify a time point at which the beacon of each relay is transmitted based on the relay RAW allocation information of the root beacon. In addition, the STA may receive a relay beacon from the relay and may associate with a relay existing in a specific channel preferred by the STA. The Root AP can display information on channels used by each relay in the Beacon, Probe Response, Relay Beacon Interval, and duration to the next Relay Beacon to inform the relay allocation status for each channel. The STA may determine an optimal relay faster based on the relay allocation situation for each channel. Shared DRAW can be allocated in PRAW format. The STA connected to the relay needs only to receive beacons from the connected relay.

The transmission between the relay and the STA in each cluster may be performed in the same form as the communication between the STA and the AP in the existing independent BSS. In a cluster, the STA may transmit within a channel range allocated for use by the relay to which the relay is connected, and may transmit within a channel range including a primary channel in the cluster designated by the relay. The relay may inform STAs by using a relay beacon of a primary channel used in a cluster of the corresponding relay in the same manner that the existing AP notifies the primary channel of the BSS through the beacon.

When RAW is shared using frequency subbands, the Root AP can allocate usage of each channel to the AP using the DRAW, and the AP can allocate detailed RAW / slot of the DRAW. Regarding DRAW assignment, if a primary channel used by a Root AP for transmission between a relay or a STA directly connected to a Root AP is not assigned to another relay, the Root AP may assign a primary channel of the corresponding DRAW to itself. Can be. The Root AP can allocate detailed RAW / slots for a Relay or STA that directly transmits to the Root AP based on the DRAW assigned to itself. In this case, in addition to the DRAW allocation information, the Root Beacon may include RAW / slot allocation information between the Root AP and the relay or the STA for the DRAW interval allocated to the Root AP itself.

When the relay wants to change the channel used in its cluster, the relay can request the root AP to change the channel used in its cluster. For example, the relay may define a relay operating mode notification frame to request the Root AP for a channel change. The Root AP that receives the channel change request from the relay sends a confirmation of the channel change request to the relay, and the relay can move the channel when the Root AP approves the channel change. When the relay changes the channel, the root AP can change the relay grouping. If a channel change in the cluster is allowed, information about the channel change may be transmitted to the STA through the existing Channel Switch Announcement.

The primary channel in the cluster, that is, the primary channel used for transmission between the relay and the STA may always be fixedly assigned, but the FST may be applied to the cluster so that the temporary primary channel may be changed for each RAW. 30 illustrates an example of allocating a frequency subband to a relay. Unlike in FIG. 29, the primary channel in the cluster is not fixed, and the primary channel may be changed in the band range allocated to the cluster for each RAW.

Specifically, FIG. 31 is a diagram illustrating an example of extending the leveled slot allocation method of FIG. 23 to a method of performing simultaneous transmission by sharing DRAW using different frequency subbands. The various types of DRAW allocation methods described with reference to FIGS. 26 to 28 may be extended to simultaneous transmission using different frequency subbands.

FIG. 32 illustrates an example in which the embodiment of the general leveled slot allocation method of FIG. 17 is extended to two relays communicating with an STA using different frequency subbands.

In DL RAW transmitted to Root AP Relay at Level 0 and UL RAW transmitted to Relay Root AP, transmission slots for Relay 1 and Relay 2 may be sequentially allocated, and slot allocation information is included in the Root Beacon to be transmitted. Can be.

DL & UL RAW for transmission between Relay 1 and STA and transmission between Relay 2 and STA may be indicated in Empty RAW (DRAW) format in the Root Beacon. In this case, information about a relay that is allowed to be transmitted in the corresponding empty RAW (DRAW) and channel information about a frequency subband allocated to each relay may be displayed in an empty RAW (DRAW) of the root beacon. For example, the information on the relay to which transmission is allowed may include AID, partial AID, BSSID, or partial BSSID for each of Relay 1 and Relay 2, and channel information about frequency subbands assigned to each Relay. Each relay may include a channel number for an allocated frequency subband, whether to allow wideband transmission including the allocated frequency subband, and information on the range of available broadband if wideband transmission is allowed. Information about the range of available broadband can be used to prevent the use of overlapping channels between relays.

Each relay may allocate a transmission slot for an STA connected to the relay beacon.

In FIG. 32, since Relay 1 and Relay 2 use different frequency subbands, simultaneous transmission is possible in a corresponding DL & UL RAW period (shared RAW).

Each relay can allocate different UL and DL intervals as needed in the shared RAW. For example, if Relay 1 has more UL transmissions from the STA than Relay 2, Relay 1 may allocate more UL slots than Relay 2.

The Root AP can negotiate with the Relay whether each relay uses RAW sharing using frequency subbands or which frequency subband is preferred when connecting to the Root AP. In addition, even after the relay is connected to the Root AP, the Root AP may change the use of RAW sharing and the preferred frequency subband through an operating mode change request / response between the Relay and the Root AP.

The root AP may allocate the same channel to a specific relay transmission section to a specific relay, or determine an optimal channel for each relay transmission section, and allocate an optimal channel to the relay transmission section according to the determination result.

The Root AP may assign a frequency subband so that the Relay uses only a specific frequency subband (e.g. 2 MHz), and allow the relay to use a wider frequency subband (e.g. 8 MHz) that includes the specified frequency subband Allowed.

If the Root AP allows a wider frequency subband to be used for a relay, there is a risk of using overlapping frequency subbands among the relays that share RAW, and the Root AP has a selectable channel number and band to prevent this risk. The width limit can be set.

As described above, transmission efficiency may be improved by enabling simultaneous transmission between different clusters.

33 illustrates an example of a method of sharing RAW by using different frequency subbands in a leveled slot allocation method using empty slots according to an embodiment.

FIG. 33 is an extension of the embodiment of FIG. 18, and an area 3310 illustrates a section in which simultaneous transmission between clusters is possible.

The DL slot allocation for RAW 2 'and the UL slot allocation for RAW 3' may be displayed in the form of Empty slot in Root Beacon. At this time, the Root Beacon may display information on relays that are allowed to be transmitted in the corresponding empty slot and channel information on frequency subbands allocated to each relay. For example, the information on the relay to which transmission is allowed may include AID, partial AID, BSSID, or partial BSSID for each of Relay 1 and Relay 2, and channel information about frequency subbands assigned to each Relay. Each relay may include channel number for the assigned frequency subband, whether to allow wideband transmission including the assigned frequency subband, and information on the range of available broadband if wideband transmission is allowed. Information on the range of available broadband can be used to prevent the use of overlapping channels between relays.

When the frequency subchannel used by the relay is changed for each relay transmission period, the relay may transmit a sounding frame for each channel immediately after transmitting the relay beacon. STAs connected to the relay can find the optimal channel based on the sounding frame, and the relay can improve transmission efficiency by transmitting data based on the optimal channel selected by the STA.

34 to 35 illustrate another example of a method of sharing RAW using different frequency subbands in a leveled slot allocation method using an empty slot according to an embodiment.

FIG. 34 expands on the embodiment of FIG. 19 and illustrates an embodiment in which shared DL RAW and UL RAW are allocated to one shared RAW (UL / DL RAW). FIG. 35 expands on the embodiment of FIG. 20 and illustrates an embodiment in which DL RAW and UL RAW are shared in transmission between Relay1 and STA and transmission between Relay2 and STA.

36 illustrates another example of a method of sharing RAW using different frequency subbands in a leveled slot allocation method using an empty slot according to an embodiment.

FIG. 36 illustrates an embodiment in which the DL RAW and UL RAW are allocated as one shared RAW (DL / UL RAW) in the transmission between Relay1 and STA and the transmission between Relay2 and STA. Doing. By allocating DL / UL RAW as one RAW, it is possible to flexibly allocate UL slots and DL slots between STA / Relay1 and STA / Relay2 according to circumstances so that RAW can be utilized more efficiently. In FIG. 36, since UL 1 has more UL transmissions from the STA than Relay 2, more UL slots are allocated to Relay 1.

<1.1 Signaling Method for RAW Sharing Using Frequency Subbands>

In RAW sharing using frequency subbands, the Root AP tells the Relay which AP, for which frequency, for which duration, transmissions have been allocated in a particular time interval (e.g., a specific RAW or a specific slot). Information can be informed via signaling.

The Root AP may transmit information about a relay allowed for transmission during DRAW and information on a transmission allowance period to the relay using a Root Beacon RPS IE or a new IE similar to the RPS IE. Information about a relay that is allowed to transmit may inform information such as relay AID, partial AID, or partial BSSID.

For example, the signaling method may be performed based on Table 1 below. Table 1 shows DRAW Signaling (signaled in Root Beacon for level 0).

Root Beacon may include DRAW allocation information.

The information shown in Table 1 may use the RAW Start Time and RAW Duration information of the existing RPS IE, add DRAW indication and DRAW allocation information to the RPS IE, or define a new IE containing similar information. have.

Since the relay and the root AP know channel information negotiated with the root AP for use by each relay, the root AP does not need to inform the DRAW unit about which channel is allocated to which relay in each DRAW. For example, the channel information negotiated with the Root AP for use by the relay includes information regarding channel numbers or bitmaps that allow transmission for a specific relay, whether wideband transmission including the assigned frequency subbands is allowed, etc. can do. However, in order to transmit information about available channels and relays to STAs newly connected to the Root AP or Relay, or to allow other STAs to use the remaining RAW section when RAW is not allocated or a RAW transmission section remains The Root AP may inform the Beacon of whether a channel is available by including a relay allocation bitmap for each channel.

Root AP can allocate subchannels to itself when using DRAW sharing. In this case, the DRAW signaling information may include the AID, partial AID, BSSID, or partial BSSID of the root AP, and RAW / Slot allocation information for transmission between a relay or STA that transmits directly to the root AP and the root AP in the root beacon. May be included.

When the PRAW type is used, one bit indicating whether or not a PRAW and information about a period of the PRAW may be additionally included in the root beacon. For example, the period of the PRAW may be an integer value indicating how many times the short beacon. Alternatively, one bit indicating whether a PRAW is omitted may be omitted, and only information about a period of the PRAW may be additionally included in the root beacon, in addition to the items in Table 1.

DRAW signaling when DRAW sharing is not performed may be performed in the same manner as described above, except that only one relay that is allowed to be transmitted is designated in DRAW allocation.

The strictly disallowed bit indicates whether to explicitly prohibit transmission of a specific relay or STA among the allocated intervals. If the strictly disallowed bit is 1, the strictly disallowed relay and STA information may be included in the DRAW. The strictly disallowed bit may be used to indicate whether to disallow the entire relay BSS or to disallow some STAs of the relay BSS.

Table 2 below shows Empty RAW signaling information included in a relay beacon.

Empty RAW indicates an interval in which STA transmission in the cluster is prohibited outside the DRAW interval at level 1. If marked as Empty RAW, STAs in the cluster are prohibited from transmitting data for the period specified as RAW Start Time, RAW duration.

As another example, an interval in which the AP enters a power save may be explicitly indicated. If the AP Power Save bit is set to 1 in the RPS IE, this indicates that the AP sleeps in the corresponding RAW period, and the STA does not transmit data to the AP. Empty RAW signaling may be performed using the AP Power Save bit. If you set the interval for setting Empty RAW to RAW and set the AP Power Save bit to 1, STAs do not transmit in the DRAW or RAW interval.

On the contrary, the AP power save can be explicitly indicated by using the Empty RAW signaling method. If the AP sets the power save interval to Empty RAW, the STA may explicitly indicate the AP power save since the STA does not transmit the interval set to Empty RAW. In this case, since the empty RAW definition has much fewer bits than the existing RPS IE definition, the application of empty RAW to the AP Power Save indication can further reduce the length of the RPS IE.

In another embodiment, both the Empty RAW indication bit and the AP Power Save bit may be displayed in Empty RAW. In Empty RAW, transmission between the STA connected to the Relay and the Relay is not allowed, but since the Relay performs transmission with the Root AP in Empty RAW and may not actually save power, the Empty RAW indication bit and the AP Power Save bit are used. By doing so, it is possible to clearly indicate whether or not the actual relay is sleeping.

In the case of an explicit allocation of Empty RAW periodically, the PRAW form may be used. When the PRAW type is used, one bit indicating whether or not a PRAW and period information of the PRAW may be additionally included in the root beacon. For example, the period of the PRAW may be an integer value indicating how many times the short beacon. Alternatively, one bit indicating whether a PRAW is omitted may be omitted, and only information about a period of the PRAW may be additionally included in the root beacon, in addition to the items in Table 1.

If explicitly prohibiting STA transmission within the cluster outside of DRAW, Empty RAW is not used and the Relay allocates 1 bit in the Relay beacon to indicate that transmission is prohibited except for the DRAW or RAW interval explicitly assigned by the Relay. Can be represented. For example, if the allocated bit is 1, the STA cannot transmit other than an interval in which RAW or DRAW is explicitly set.

As another example, an interval in which the AP enters a power save may be explicitly indicated. If the AP Power Save bit is set to 1 in a short beacon or a beacon, the STA may be prohibited from transmitting to the AP except for an explicitly allocated RAW period. The AP Power Save bit can be used to indicate whether transmission is prohibited other than the DRAW or RAW period in the relay. Clearly, if the transmission is prohibited except for the DRAW or RAW period in the relay, STAs do not transmit in the DRAW or RAW period by setting the AP Power Save bit to 1 in the relay beacon.

The RAW information allocated by the relay to the STA at level 1 is similar to the RAW information of the existing 802.11ah. When FST is used in a cluster, primary channel information for FST transmission may be included in the RPS IE of the relay beacon as in the existing 802.11ah standard.

In addition, the following modified examples (Option 1, Option 2) are also possible. In the following description, empty slot or empty RAW at level 0 indicates a delegated slot or DRAW.

When using an empty slot, RPS IE may include the following information.

1) RAW Start Time: The RAW Start Time represents the start time of RAW that contains a shared empty (delegated) slot.

2) RAW Duration: RAW Duration represents the Duration of RAW that contains a shared empty (delegated) slot.

3) Empty (delegated) slot definition: An empty (delegated) slot definition indicates the start and end times of an empty (delegated) slot. For example, an empty (delegated) slot definition may include a start slot number and an end slot number. If there are several empty (delegated) slot groups in the same RAW, the start and end times of the above empty (delegated) slots can be represented as a list. If an empty (delegated) slot definition indicates that the Root AP uses an empty (delegated) slot, an Empty (delegated) Slot allocation field must exist, and between the relay APs indicated in the empty slot allocation field and an STA connected to the corresponding relay AP. Only transmissions can indicate that they are allowed in a shared empty slot. If the relay AP configures an empty (delegated) slot definition field, an empty (delegated) slot allocation field may not be necessary, which may indicate that only transmission between the relay AP and the root AP is allowed. Clearly, the empty RAW indication at level 1 may be used only when prohibiting transmission of the STA.

4) Empty (delegated) slot allocation: Empty (delegated) slot allocation can be used only for RPS IE or DL / UL allocation frame of Root AP. An empty (delegated) slot allocation may include a list of relay APs that are allowed to transmit to STAs connected in an empty (delegated) slot and frequency subband information that can be used by the relay AP. Subband information may be included only when RAW sharing using frequency subbands is used. When performing simultaneous transmission or spatial sharing between spatially separated clusters or RAW sharing in a time domain, information about frequency subbands does not need to be included. The Root AP and the Relay may share frequency subband information in advance or may include a band allocation map in the root beacon and not include the band allocation information. For example, the list of relay APs that are allowed to transmit may include information such as AID, partial AID, BSSID, partial BSSID, etc. of the relay APs that are allowed to transmit. Allowed channel number or bitmap, or whether wideband transmission including the assigned frequency subband is allowed or the like. When the Root AP allows transmission to a wider frequency subband than the selected frequency subband, it indicates the channel or bandwidth that is allowed to be used by using a bitmap, so that there is no overlapping channel among the relays. Should be.

In addition to the above information, the RPS IE may further include information such as slot definition, Group / Resource allocation frame indication, Access restricted to paged STA only.

When using Empty RAW (DRAW), the RPS IE may include the following information.

1) RAW Start Time: The RAW Start Time represents the start time of the shared RAW.

2) RAW Duration: RAW Duration represents the duration of shared RAW.

3) Empty RAW (DRAW) indication: The Empty RAW (DRAW) indication indicates whether RAW is used as empty RAW (DRAW). If the Empty RAW (DRAW) indication indicates that the Root AP uses empty RAW (DRAW), the Empty RAW (DRAW) allocation field must exist, and the Relay APs and corresponding Relay APs shown in the empty RAW (DRAW) allocation field. Only transmissions between STAs connected to the nodes are allowed in the shared empty RAW. If the relay AP sets the Empty RAW (DRAW) indication field, the empty RAW (DRAW) allocation field may not be necessary, which may indicate that only transmission between the relay AP and the root AP is allowed. Clearly, the empty RAW indication at level 1 may be used only when prohibiting transmission of the STA.

4) Empty RAW (DRAW) allocation: Empty RAW (DRAW) allocation can only be used for RPS IE of Root AP. Empty RAW (DRAW) allocation may include a list of relay APs that are allowed to transmit with STAs connected in empty RAW (DRAW) and frequency subband information that may be used by the relay AP. Subband information may be included only when RAW sharing using frequency subbands is used. When performing simultaneous transmission or spatial sharing between spatially separated clusters or RAW sharing in a time domain, information about frequency subbands does not need to be included. For example, the list of relay APs that are allowed to transmit may include information such as AID, partial AID, BSSID, partial BSSID, etc. of the relay APs that are allowed to transmit. Allowed channel number or bitmap, or whether wideband transmission including the assigned frequency subband is allowed or the like. The Root AP and the Relay may share frequency subband information in advance or may include a band allocation map in the root beacon and not include the band allocation information. When the Root AP allows transmission to a wider frequency subband than the selected frequency subband, it indicates the channel or bandwidth that is allowed to be used by using a bitmap, so that there is no overlapping channel among the relays. Should be.

<2. How to perform RAW sharing when clusters are spatially separated>

37 illustrates an example of a RAW sharing method when clusters are spatially separated according to an embodiment. 37 shows an example of using an empty RAW, and can be extended in a similar manner even when using an empty slot. The region 3310 represents a section in which clusters are spatially separated and transmitted simultaneously. The signaling method is similar to the signaling method in RAW sharing using frequency subbands.

<3. How to perform RAW sharing using the time domain>

38 illustrates an example of a method of performing RAW sharing using a time domain according to an embodiment. 38 illustrates an example of using an empty RAW, and may be extended in a similar manner using an empty slot. The region 3410 represents a section in which RAW is shared by sequentially transmitting in the time domain.

In a shared RAW or slot, a Relay or STA sequentially transmits through contention. The method of performing RAW sharing using the time domain is a method that can be used when the number of STAs connected to each relay is not large or the transmission amount is not large. The signaling method is similar to the signaling method in RAW sharing using frequency subbands.

Another method that can be considered in the DRAW transmission method is a method in which the Root AP does not set the DRAW as a section for transmission in the Relay BSS and allocates the DRAW to the Root AP and the UL / DL transmission section in the DRAW. Using this method, the relay can properly allocate RAW / slots directly from the relay, from the relay to the Root AP, as well as level 1 transmission within the relay within the range of DRAW.

The UL / DL transmission RAW / slot from the relay to the Root AP is displayed on the relay beacon, and the transmission slot indication to the Root AP may be displayed in a similar manner to the STA belonging to the Relay BSS in the RPS IE. For example, when the slot is allocated, the relay may transmit the AID of the Root AP to the Root AP, and the UL / DL transmission to the Root AP may be indicated as DL / UL transmission for the AID of the Root AP in the RPS IE. Can be.

<(B) Root AP allocates resources such as relay transmission section and transmission band to relay independently of RAW of Root AP by using resource allocation information other than RAW type (Relay Resource Allocation IE) How to)

The method of using DRAW in the above (A) is to allocate the section set by the Root AP to the relay, and it is possible to simply extend the existing RAW signaling method and to use Empty RAW signaling to protect the transmission section. DRAW has the advantage of simultaneous resource allocation. When the relays use a different channel from the root AP, the relays can transmit independently of the root AP in their assigned frequency subbands, so the transmission interval of the relay does not need to be determined based on the RAW of the root AP. In the method of (B), the Root AP can allocate resources to the relay by using separate resource allocation information independent of the RAW allocation of the Root AP, and thus, the Relay and Root APs in different frequency subbands Transmission can be performed in an independent section.

In the following, a general case of using multiple frequency subbands will be described, which includes a single band case.

The Root AP can transmit resource allocation information necessary for transmission between the relay and the STA in the Root Beacon in a separate Resource allocation IE form. In case of relay operation considering multiband transmission, Root AP can allocate resources for each relay to minimize transmission of different relay clusters in the same frequency subband at a specific time. Root APs can allocate resources to allow different relays to transmit within the cluster using different frequency subbands as much as possible at any given time to enable simultaneous transmission.

The resource to be allocated may include transmission allowable start time and transmission interval length for each relay in the cluster, channel information to be used when each relay uses the intra-cluster transmission.

After connecting to the Root AP as a STA, the Relay may request that the Root AP set up a Relay BSS and operate as a Relay AP, and then, when approved by the Root AP, operate as a Relay AP.

When the Relay requests to connect to the Root AP as an STA or requests the Root AP to operate as a Relay AP, the Relay provides channel related information such as channel and bandwidth and primary channel information that the Relay intends to use for cluster transmission, Resource allocation requirements such as a relay beacon interval and an initial relay BSS transmission duration may be transmitted to the root AP. The relay can also transmit information on the degree of separation for other relay BSSs to the Root AP along with resource allocation requirements. The relay can operate as a relay AP by setting up a relay BSS using a channel allocated from the root AP and a relay beacon interval and transmitting a relay beacon at a predetermined time. When the relay is connected to the Root AP, or requests the Root AP to operate as a Relay AP, or after that, it can transmit information to the Root AP to determine the required transmission time. For example, the relay may transmit information such as mean data rate, target wake time, or wake period of STAs connected to the relay to the root AP. The Root AP may allocate an appropriate transmission interval to the relay based on the information received from the relay. Root AP may allocate the same transmission interval to the relays spatially separated from each other based on the information on the degree of separation for the other relay BSS received from the relay. In addition, the relay AP may periodically or aperiodically measure the degree of spatial separation with other relay BSSs, and if the degree of spatial separation with other relay BSSs is changed by more than a preset reference, the relay AP may feed back the changed contents to the root AP. For example, the relay AP may receive a lot of interference from another relay BSS that has been previously separated, or vice versa, when a new relay BSS is detected, it may notify the root AP about this. The Root AP may allocate transmissions of newly spatially separated relays to the same section based on spatial separation information between the relays.

The relay and the root AP know the channel allocation information for the relay, and in order to minimize the length of the resource allocation information delivered to each beacon, the channel allocation information for each relay may be transmitted without being included in the resource allocation information. . Channel information allocated to each relay may be included in resource allocation information delivered for each beacon. The relays can identify channel assignment information of different relays based on the root beacon and check the relays assigned to the same channel as their own.

When such resource allocation is the same in every beacon section, the resource allocation information may not be transmitted every time, but may be transmitted by including the period information on resource allocation in the long beacon and the like. In this case, the changed resource allocation information only needs to be transmitted when the resource allocation is changed.

The Root AP may include resource allocation information in the Root Beacon and transmit it, and the Relay may allocate RAW for the transmission time allowed for transmission to the cluster based on the resource allocation information included in the Root Beacon. The relay may include the RAW allocation information for the STA in the relay beacon and transmit the same to the STAs connected thereto. Transmission between the relay and the STA may be performed in the allocated resource. The relay may use a relay beacon transmission channel and a channel transmitted with an STA in a cluster may negotiate with a root AP in advance and use an allocated channel. Channel allocation information may be indicated or omitted using relay resource allocation information. The channel allocated by the root AP may be used for transmission between the relay and the root AP. Transmission between the relay and the root AP may be performed based on a transmission interval allocated by the root AP to the root beacon in RAW.

In the above method, the leveled method may be used in the same manner as the method (A). That is, the root AP may allocate only resources for the relay cluster and not allocate RAW of the STA connected to the relay in the relay cluster. The Root AP allocates only RAWs for STAs and relays directly connected to the Root AP, and RAW allocations for STAs connected to each relay can be allocated within resources such as a transmission channel and a transmission interval allocated by each relay.

The RAW / slot allocation information may be identified based on the relay beacon of the STA connected to the relay, and may be confirmed based on the root beacon.

Root AP can set Empty RAW to Root Beacon similar to the method (A) to protect the transmission of the relay cluster when transmitting between relays using the same frequency subband as Root AP. That is, the Root AP can allocate all or part of the relay transmission section using the same frequency subband as the Root AP to Empty RAW, and STAs and relays connected directly to the Root AP can be assigned to Empty RAW based on the Root Beacon. You may not send it. Accordingly, transmission of a relay cluster allocated to the same frequency subband as that of the Root AP in the time interval indicated by Empty RAW can be protected.

A protection method for preventing STAs from transmitting outside of the explicitly allocated relay cluster transmission interval in each relay cluster includes a method of setting empty RAW in the same manner as method (A), or transmitting other than explicitly allocated RAW. Disallowed methods may be used.

In order to prevent the STA in the Root BSS from colliding with another Relay BSS transmission interval using the same channel, the Root AP explicitly sets another Relay transmission interval to Empty RAW (or AP PM RAW) to prohibit transmission of the STA. Can be. The Root AP determines the spatial separation between the Root BSS and other Relay BSS, and if the space is not sufficiently separated, the Root AP sets the transmission interval of the other Relay to Empty RAW (or AP PM RAW) and is connected to itself in the transmission interval of the other Relay. Transmission of the STA may be prohibited. or. The Root AP may not prohibit transmission of all STAs in the Root BSS for other Relay transmission intervals, and may prohibit transmission only for a specific STA that has much interference with other Relay BSSs among the STAs in the Root BSS. To this end, the Root AP may use a modified Empty RAW (or modified AP PM RAW) that may indicate a STA whose transmission is prohibited, or a RAW allocation method that excludes a STA whose transmission is prohibited from RAW allocation.

How the Root AP identifies whether a particular STA in the Root BSS is interfered with by another Relay BSS may be determined by the Root AP using the “Method of Determining Spatial Separation Between (BB) Relays”. A method of receiving information or informing the Root AP of a STA of a Root BSS that interferes with information on another Relay BSS or another STA that interferes with the STA may be used.

In order to prevent a collision occurring due to the STA belonging to the relay BSS transmitting in the transmission interval of another relay BSS using the same channel, the relay AP clears the transmission interval of the other relay BSS similarly to (A). (Or AP PM RAW) can be set to prohibit transmission. The relay periodically decides whether to separate spatially from other relay BSSs, and if the result is not sufficiently spatially separated, the relay may prohibit transmission of the STA connected to itself by setting the transmission interval of another relay to Empty RAW (or AP PM RAW). Can be. Alternatively, the relay does not prohibit transmission of all STAs in the relay BSS with respect to another relay transmission interval, but may also prohibit transmission only for a specific STA that has much interference with other relay BSSs among the STAs in the relay BSS. To this end, a modified Empty RAW (or modified AP PM RAW) that may indicate a STA whose transmission is prohibited, or a RAW allocation method for excluding a STA whose transmission is prohibited from the RAW allocation may be used.

If there is a frame to be urgently transmitted by the Root AP, transmission in an interval other than the transmission interval allocated for Root BSS transmission may be exceptionally allowed. In addition, even for a level 1 transmission, even if the STA is not allocated to the relay to which the relay belongs, the STA does not detect transmission in another relay BSS or based on a beacon of another relay, Data can be transferred exceptionally for sections that are not assigned RAW.

Alternatively, both STAs belonging to the Root AP and STAs belonging to the Relay may be allowed to transmit data through contention, such as transmission in an existing OBSS environment, even in a period where transmission to the AP is not allocated. However, when data is transmitted in a section not allocated to its BSS, since the collision probability is high, it is preferable that the STA performs RTS / CTS before data transmission.

The relay or the root AP may explicitly prohibit transmission of STAs connected to the self by setting an empty RAW period in which a collision or contention is expected to be severe among transmission periods not allocated to the relay or root AP. In addition, the relay or the root AP may prohibit the STA from transmitting to the relay in the period in which the transmission between the relay and the root AP occurs by setting the empty RAW interval between the relay and the root AP.

The protection method for resources allocated to other relays above is similarly applicable to the method using (A) DRAW.

The relay can explicitly request the Root AP for protection of resources allocated to it. In response to the relay's request, the Root AP may explicitly prohibit the Relay from transmitting certain relay BSSs or some STAs (including STAs of the Root BSS) for the allocated resources of the transmission interval. .

For example, a relay receives severe interference from transmissions of a specific STA belonging to another Relay BSS, another Relay BSS, or STAs directly connected to a Root BSS, and thus, relays of all other Relay BSSs or all other Relay BSSs in a transmission interval assigned to the relay BSS are allocated to them. If it is desired to prohibit transmission of some STAs or STAs directly connected to the Root BSS, the relay may request protection of a resource allocated thereto from the Root AP. When requesting protection from the root AP, the relay may transmit to the root AP a list of other relay BSSs or specific STAs that are interfering.

In addition, each STA in the relay BSS may also transmit information on the relay BSS or a specific STA that has severe interference to the relay AP, and the relay AP may transmit the relay BSS and the STA information received from the STA to the root AP. Can be. In this case, STAs may not need a measurement function such as 802.11k. When the STAs have a measurement function in 802.11k, the relay AP may request a measurement from the STA and determine other relay BSSs and STAs that interfere with the STA connected to it based on the measurement results from the respective STAs. have. The relay AP may notify the Root AP of other relay BSSs and STAs determined.

When the Root AP receives a resource protection request from a relay, the Root AP may indicate specific STAs of a Relay BSS or Relay BSS that should not be transmitted in a corresponding transmission interval in a resource allocation IE for a relay that has made a resource protection request. .

The relay does not transmit in the transmission interval of the other relay BSS if it is included in the relay prohibited list of the resource allocation IE of the other relay BSS. The relay may protect the resources of the relay requesting resource protection by allocating empty RAW (or AP PM RAW) to the STA belonging to it and explicitly prohibiting transmission of the STA. If it is indicated in the relay resource allocation IE to prohibit transmission of some STAs among the relay BSSs instead of the entire relay BSS, the relay may prohibit transmission of only a specific STA designated for the corresponding relay BSS transmission interval. The relay resource allocation location IE indicates resource allocation information regarding resources for transmission between the relay and the STA connected to the relay, allocated by the root AP. Based on the Relay Resource Allocation IE, which relay can communicate with the STA in which time period may be determined.

When the relay requests that the specific STA in the Root BSS receives interference, the corresponding STA may not be included in the Relay Resource Allocation IE, and the Root AP may prohibit transmission of the STA during the Relay transmission period.

The protection method for resources allocated to the relay itself is similarly applicable to the method using (A) DRAW. In the case of (A), the strictly disallow bit, the relay AP, and the STA list may be displayed through fields of the DRAW.

If all the information of the strictly disallowed STA is displayed in the Relay Resource IE as described above, the size of the beacon may be too large. As another method, the Root AP collects information on the relay AP and STA to be strictly disallowed and received from the relay, and broadcasts a message including the relay AP and STA information to strictl disallow for each Relay BSS to each Relay, or There is a method of delivering using a separate frame in unicast. A relay that receives a message containing information on the relay AP and STA to be strictly disallowed checks whether or not it is strict disallowed by itself or the STA connected to it in the transmission interval of another relay, and when it is confirmed that the relay is disallowed, Do not transmit in the transmission section.

The relay initially attempts to connect to the Root AP as an STA for the Root AP. After that, the relay may request that the Root AP set up a Relay BSS and operate as a Relay AP, and then operate as a Relay AP if it is approved by the Root AP.

The relay requests the Root AP with an association request for the resources necessary for its cluster to operate as a Relay AP, or a Relay SetUp request when the Root AP is requested to operate as a Relay AP. Can be requested to Root AP. For example, a relay may include the following information in an association request or a relay setup request and transmit the following information to a root AP.

1) Channel allocation request information for Relay Cluster: Relay BSS Starting Channel Number, Relay Primary Channel Number, Relay Bandwidth (Relay BW) It may be included in the channel allocation request related information. The relay can transmit the channel candidate list to be used to the root AP. Root AP allocates a channel that does not overlap with another relay BSS to the relay, and if a plurality of relays are allocated to the same frequency subband, relays using the same frequency subband can be allocated to different time intervals. When the current relay is spatially separated from other relay BSSs, the root AP may allocate the same frequency subband to the current relay BSS and another relay BSS even in the same time interval.

2) Relay Beacon Interval: Relay Beacon Interval indicates the transmission period of Relay Beacon, and Relay can negotiate with Root AP for Relay Beacon Interval. The relay periodically transmits the relay beacon after the relay BSS setup, and the root AP can allocate a time when the relay transmits the relay beacon and a certain time thereafter to the corresponding relay. When the relay cluster uses the same frequency subband as the root AP, the root AP can protect the transmission period of the relay cluster by using an empty RAW.

The relay beacon may be transmitted first of the transmission periods allocated to the relay. Alternatively, the Root AP can allocate a relay beacon transmission RAW after the root beacon. Each relay can transmit a relay beacon based on the assigned relay beacon transmission RAW. In this case, the transmission interval allocated to each relay and the time point at which the relay beacon is transmitted may not immediately follow.

In addition, the relay has requirements such as a relay transmission duration (for example, a transmission time required by the relay during the full beacon interval of the root AP) or information related to the transmission interval for allowing the root AP to determine the relay transmission interval. Can be transmitted to the Root AP. For example, the transmission interval related information may include a mean data rate, a target wake time, or a wake period of the STAs connected to the relay. The root AP can allocate a time interval required for each relay cluster based on the requirement received from the relay or information on the transmission interval. Relay can transmit relay transmission section related information to Root Ap when connecting to Root AP or relay setup request. Alternatively, the relay may exchange related information by using an additional resource allocation request frame after being connected to the root AP. The relay can also transmit information on the spatial separation degree of other relay BSSs to the root AP.

The Root AP may respond to the Association Request of the Relay with an Association Response, and may transmit information including information on the transmission interval allocated by the Root AP in the Association Response frame. have. Alternatively, when the relay delivers a relay related parameter to the Root AP using a separate Relay Setup request, the Root AP may include information on a transmission interval allocated by the Root AP in a response frame. For example, the Root AP may inform the Relay of channel allocation information such as Relay BSS Starting Channel number, Relay Primary channel number, Relay BW, and Relay Beacon Interval allowed by the Root AP. In addition, the root AP can inform the relay of the negotiation result related to the relay transmission interval.

The information initially allocated to the relay by the Root AP may be changed by using an additional operation mode change request / response frame or a resource allocation change request / response frame. When the number of STAs connected to the relay increases or decreases, resources required for transmission of the relay cluster may vary. The relay can request the relay cluster bandwidth and relay transmission interval requirements even after being connected to the root AP so that the entire resource can be utilized more efficiently. If the channel used in the relay BSS is changed, the relay AP may inform the STAs connected to it by using the channel switch announcement frame used in the existing 802.11 standard.

Root AP may allocate the same transmission interval to the relays that are spatially separated from each other based on the information about the spatial separation degree for the other relay BSS transmitted by the relay.

In addition, the relay AP may periodically or aperiodically measure the degree of spatial separation from other relay BSSs, and if the degree of spatial separation from other relay BSSs is changed by more than a predetermined reference value, the relay AP may feed back the changed contents to the root AP. For example, the relay AP may receive a lot of interference from another relay BSS that has been previously separated, or vice versa, when a new relay BSS is detected, it may notify the root AP about this. The Root AP may allocate transmissions of newly spatially separated relays to the same section based on spatial separation information between the relays.

Specifically, FIG. 39 shows an example of allocating different frequency subbands to several relays and root APs to enable simultaneous transmission. In FIG. 39, transmission between the STA connected to Relay 1 and Relay 1, the transmission between STA connected to Relay 2 and Relay 2, and the transmission between STA or Relay directly connected to Root AP and Root AP are performed simultaneously through different channels. Can be. Relays and root APs using different frequency subbands can transmit independently, and relays using the same frequency subbands (for example, Relay 1 and Relay 3) transmit in different transmission intervals. Should be performed. The STA may communicate with the relay using the frequency subband used by the connected relay, and the relay may communicate with the root AP using the frequency subband allocated by the root AP.

In detail, FIG. 40 illustrates an example in which different frequency subbands are allocated to various relays and root APs for simultaneous transmission. In contrast to FIG. 39, the frequency subbands are allocated so that some channels overlap each other. Such overlapping channel assignment may be useful when there are not many channels available. Primary channels of each relay AP and root AP may not be allocated redundantly, and only secondary channels may be allowed to be allocated. If the channel is not enough, the Root AP can allocate some channels redundantly, as shown in FIG. 40, and the channel assignment information for each relay including the assignment of the duplicated channel (this is called 'Default channel assignment information'). ) Can be sent to Relay. The channel allocation information is shared in advance by the relay and the root AP, and may not be explicitly informed through the relay resource allocation IE or may be explicitly informed through the relay resource allocation IE. If the channel allocation information is not explicitly communicated through the relay resource allocation IE, the Root AP will inform which relay used the channel allocated in a specific time interval when transmitting the resource allocation IE (ie, resource allocation). Can be. Root AP can inform additional information to be known when resource allocation through resource allocation IE. Additionally, the information to be known may include information on who will use the duplicately allocated channel. If there is no additional channel allocation information in the resource allocation IE, the relay can use the channel allocated to itself including the duplicated channel. If a specific relay is used for a duplicate channel, the Root AP can prevent the channel from being used for another relay that has been assigned a channel. For example, the Root AP can deliver a reduced bandwidth or an unused channel number to another relay that has been assigned a channel.

For example, if CH 2 is assigned to Relay 5 and Relay 3 simultaneously, and CH 2 is assigned to Relay 5 at a specific point in time, the Root AP informs Relay 3 of the reduced bandwidth than the initial allocated bandwidth, or Resource allocation IE can be told not to use duplicate channels allocated to Relay 3. The resource allocation IE delivered to relay 5 may not include duplicate channel allocation related information. In other words, if there is no information related to the allocation of redundant channels explicitly in the resource allocation IE, the relay can use all channels allocated to itself including the duplicated channels. Conversely, if the resource allocation IE does not use a duplicated channel, or if channel allocation information is indicated to use a reduced bandwidth excluding the duplicated channel, then the relay will have a reduced bandwidth (that is, a bandwidth excluding the duplicated allocated channel). Can be used to perform transmission in the cluster.

In addition, when a certain amount of transmission of a specific relay is temporarily high and there is room in the channel, the Root AP may temporarily allocate an additional channel for the corresponding relay in addition to the initially allocated channel. The Root AP can transmit additionally allocated channel information (eg, additionally allocated channel number) or increased bandwidth in the resource allocation IE for the corresponding relay. A relay that receives additionally allocated channel information or information about increased bandwidth may use a channel additionally allocated by the root AP.

An example of a method of notifying the overlapping channel allocation or the temporary additional channel allocation to the resource allocation IE is as follows.

(a) Option 1: Mark channel number + 0/1. '0' is used to inform transmission prohibition for the initially overlapped allocated channel, and '1' indicates transmission allowance. Channel information may be omitted when allowing transmission to the initially allocated overlapped channel. When Root Ap temporarily allocates additional channels, the number of additional allocated channels may be displayed in the resource allocation IE.

(b) Option 2: Displays the bandwidth of the changed channel. If the relay does not allow transmission on the duplicated channel, the bandwidth is reduced from the initial allocated bandwidth, so the root AP delivers the reduced bandwidth to the relay. If the Root Ap temporarily allocates additional channels, the Root Ap can transmit information about the increased bandwidth through the Resource allocation IE. In this case, since only the variable bandwidth information needs to be represented, the size of the allocation IE does not increase even if a number of additional channels are allocated. Relay Resource Allocation In case of explicitly telling channel information such as starting channel number, primary channel, and bandwidth allocated to IE, what relay is overlapped channel assigned, and what is temporarily changed bandwidth? There is no need to inform.

In case of notifying information different from initial channel allocation through duplicate channel allocation or temporary additional channel allocation through Resource allocation IE, 1) Relay sends relay relay beacon when the bandwidth is temporarily changed for the entire relay beacon interval. The BSS bandwidth can be reported. The relay can inform the relay BSS bandwidth as a full beacon, and even when the relay beacon is a short beacon format, the relay beacon can inform the STAs of the cluster by using the BSS bandwidth field of the FC of the relay beacon. have. In addition, 2) the relay can display channel information in the RAW for the section where the bandwidth is changed when the bandwidth of the relay BSS is changed only for a section of the relay beacon interval. For example, the relay may indicate a section in which the bandwidth is changed as 'center frequency + channel bandwidth' or 'bandwidth'. If the secondary channel increases or decreases in only one direction, the relay only needs to advertise the changing bandwidth. The channel assignment can be changed only for the secondary channel of the relay BSS.

When the Root AP temporarily changes the channel allocated to itself, the Root AP can notify the channel allocation information change by displaying the channel information in RAW only for the changed time interval.

<(B) Resource Allocation Signaling Method in a Resource Allocation Method Using Resource Allocation Information>

To inform the resource allocation, the AID (s) of the relay that is allowed to transmit, the transmission allowable start time, the transmission interval, the period information to which the resource is allocated when the resource is periodically allocated, and the frequency sub allocated when the multi-frequency subband is allocated. Additional resource allocation related information such as band information, duplicate channel allocation / temporary channel allocation, information on whether to prohibit transmission of another relay / STA for the assigned relay transmission interval, and information on relay / STA forbidden transmission Can be. Since the subband allocation information (default subband allocation information) is shared with the Root Ap when the Relay connects to the Root Ap, separate signaling is omitted in the resource allocation IE except for temporary changes such as duplicate channel allocation / temporary channel allocation. It may be. Channel information allocated to each relay may be explicitly included in Resource Allocation IE, and relays may identify channel allocation information of different relays through a root beacon. Relays can recognize relays assigned to the same channel through their root beacons. When the channel information such as starting channel number, primary channel, and bandwidth allocated to the Resource Allocation IE is explicitly informed each time, it indicates to which relay the overlapped channel is allocated and what the temporarily changed bandwidth is. There is no need to inform.

In addition, the Root AP and the Relay share information on the Relay Beacon interval through pre-negotiation, and the Root AP may allocate a Relay transmission interval to transmit the Relay Beacon based on the Relay Beacon interval. The relay resource allocation IE may be included in the root AP beacon and transmitted. The relay resource allocation IE may be transmitted through a newly defined frame.

Resource allocation information is indicated in the resource allocation IE as follows.

1) How to Display Resource Allocation Information by Relay AID

The Resource Allocation IE may include Relay AID (s), Relay start time, duration, period, and other allocation information allocated during the short beacon interval of the Root AP. For example, the other allocation information may include allocated channel information or strictly disallowed relay / STA information.

When resources are allocated periodically, the Relay Resource Allocation IE does not need to be sent every Short beacon. For example, the Relay Resource Allocation IE needs to be included only when transmitting a long beacon.

Table 3 below shows an example of Resource Allocation IE format when resource allocation information is displayed for each Relay AID. In Table 3, each field's value, field order, and the like are shown as an example, and can be changed to other similar forms.

The frequency subchannel information of the additional allocation information may be included in the case of using simultaneous transmission between relays using different frequency subchannels. 1) When the channel allocation information is implicitly displayed, that is, when the relay and the root AP share channel allocation information with each other in advance and do not explicitly specify separate relay information, the relay BW is assigned to the initial allocated BW. Only when there is a change in can be displayed in the Resource Allocation IE. For example, a relay BW may be displayed in case of additional allocation of a temporary channel or prohibition of transmission in an overlapping allocated channel. 2) When channel allocation information is clearly indicated, channel information such as starting channel number, bandwidth (BW), and primary channel allocated to the relay BSS is specified in the Resource Allocation IE. Can be displayed.

When simultaneous transmission of spatially separated relay BSSs is allowed, a plurality of AIDs can be designated, and the size of IE (Information Elemnet) can be reduced by using a plurality of AIDs when different allocation information of two relays is completely identical. . Even if relay BSSs are spatially separated, if there are different resource allocation information, each allocation information may be included for each AID.

The severely disallowed bit indicates whether to explicitly prohibit transmission of a specific relay or STA among the allocated intervals. When the severely disallowed bit is 1, the strictly disallowed relay and STA information may be included in the IE. Through the strictly disallowed bit, it is possible to indicate whether to disallow the entire relay BSS or to disallow some STAs of the relay BSS.

During a single (short) Beacon Interval, a Relay can list all allocated non-contiguous time intervals at a time, so you only need to mark the resource allocation once. When the number of relays is used, the length of Resource Allocation IE may be long because start time and end time must be indicated for each relay.

If there is a section where the bandwidth is temporarily changed during the section assigned to the relay, the section should be divided. However, if the Root AP aligns the time to some extent, it can prevent the display of the intervals to some extent. The same time interval may be allocated to a plurality of relays. In this case, the same time information may be displayed in the allocation information of the relay to be transmitted simultaneously. If transmission is not completed in a time interval allocated to a specific relay cluster, a transmission interval allocated for simultaneous use in multiple relay clusters may be used to complete the transmission.

FIG. 41 is a diagram illustrating an example of a format for Relay Resource Allocation IE of Table 3 according to an embodiment. FIG. Relay Resource Allocation IE may include resource allocation information allocated to various relays for each AID. Resource allocation for each relay is defined in the Relay N Allocation field, and a number of time intervals in which a relay is allocated may be defined in each Relay N Allocation field. For example, a time interval in which a relay is assigned represents a time interval allocated in one root beacon.

2) How to display allocation information for each frequency subband where an assigned relay is located

For example, in the Relay Resource Allocation IE, for each frequency subband, "{frequency subband, {Relay AID assigned to frequency subband, Relay start time, duration + period, Strictly disallow, list of strictly disallowed Relay AP or STAs in the Relay BSS} list} "may be used to display allocation information. The frequency subband allocation information for each relay is shared when the relay is initially connected to the root AP, and the allocation information of the frequency subbands for each relay need not be displayed for each frequency subband.

3) How to display resource allocation information for each time interval

42 is a diagram illustrating an example of allocating resources for each time interval, according to an embodiment. (short) divide the beacon interval into time intervals, and for each time interval "{Start Time, Duration + period, {other assigned information such as relay AID assigned to the time interval, channel assignment information, Strictly disallow, list of strictly disallowed Relay AP or STAs in the Relay BSS} list} "may be displayed in the Relay Resource Allocation IE. Here, the time interval represents a longer time interval than RAW.

Table 4 below shows a format of Resource Allocation IE in the case of displaying allocation information for each time section.

It is not necessary to display the start time and end time of a time section several times for each relay. Relays belonging to the same section are displayed only once. The format of Resource Allocation IE may have a form similar to that of RPS IE when using RAW. If the number of relays that allow transmission in the same time zone is similar and the time intervals are similar, the method of displaying resource allocation information for each time interval is a method.If the number of relays is small and the transmission allowable time intervals of each relay are different, resource allocation information for each relay AID is used. The method of marking may be suitable.

<(B) Transmission interval protection method in the method of allocating resources using resource allocation information>

(B) In the method of allocating resources by using resource allocation information, the protection of the transmission section of the relay can use Empty RAW similarly to the method of (A) DRAW.

(A) In the method using the DRAW, at the level 0, the Root AP uses the DRAW to protect the transmission of the relay cluster using the same frequency subband as the Root AP, and the DRAW has an explicit description of the transmission protection interval. The transmission prohibition information and the relay resource allocation information for the DRAW period may be included.

(B) In the method of allocating resources using the resource allocation information, the relay resource allocation information is transmitted in the form of Relay Resource allocation IE, not RAW, and the resource protection at level 0 is (A) Level 1 of the method using DRAW. Empty RAW similar to the above can be used. According to another example, a method may be used in which empty RAW is not used for resource protection and transmission is allowed only in an explicitly allocated interval. (B) The resource protection method at level 1 of the method of allocating resources by using resource allocation information may use Empty RAW or a method of allowing transmission only in an explicitly allocated section.

Table 5 below shows a format for empty RAW signaling used when indicating a section in which transmission of an STA (level 0 or 1) or a relay (level 0) connected to an AP is prohibited. The information shown in Table 5 may be included in the RPS IE as RAW information.

At level 0, Empty RAW may be used to indicate a period in which transmission of an STA connected to the Root AP and a transmission of another relay is prohibited in a transmission period of a relay using the same frequency subband as that of the Root AP. At level 1, Empty RAW may be used to indicate a section in which STA transmission in the Relay cluster is prohibited in addition to the explicitly allocated section. If it is set to Empty RAW, the transfer is prohibited for the period specified by Empty RAW Duration, starting at Empty RAW Start Time.

In 802.11ah, in which the AP may explicitly indicate the interval for entering the power save, that the AP Power Save bit of the RPS IE is set to 1 indicates that the AP sleeps in the RAW interval, and the STA may identify the AP. Do not send to. Empty RAW signaling may be performed using this AP Power Save bit. For example, if the interval for setting Empty RAW is set to RAW and the AP Power Save bit is set to 1, the same effect as using Empty RAW may occur because STAs do not transmit in the DRAW or RAW interval.

On the contrary, AP Power Save can be explicitly indicated by extending the Empty RAW signaling method. If the AP sets the power save section to Empty RAW, the AP does not transmit the section set to Empty RAW, thereby clearly indicating the AP Power Save. Since the definition of Empty RAW is much fewer bits than the existing RPS IE definition, it is possible to further reduce the length of the RPS IE by utilizing Empty RAW for the indication of AP Power Save.

Alternatively, both the Empty RAW indication bit and the AP Power Save bit may be displayed in Empty RAW. In the level 1 period, transmission between the STA connected to the relay and the relay is not allowed in the empty RAW, but the relay performs transmission with the root AP in the level 1 period and may not actually perform power save. Therefore, when both the Empty RAW indication bit and the AP Power Save bit are used, whether or not the actual relay sleep can be clearly indicated. In the level 0 section, if the power save bit is used, the Root AP may indicate a section in which the Empty RAW section does not actually sleep, and the Root AP may allow transmission in the Empty RAW section for a STA to newly connect to the Root AP. have.

If Empty RAW is explicitly allocated periodically, the PRAW form may be used. If the PRAW type is used, one bit indicating whether the PRAW is used and period information of the PRAW may be additionally provided. For example, the period of the PRAW may be an integer value indicating how many times the short beacon. Alternatively, one bit indicating whether a PRAW is omitted may be omitted, and only information about a period of the PRAW may be additionally included in the root beacon, in addition to the items in Table 1.

If you explicitly forbid STA transmission within the cluster outside of RAW, Empty RAW is not used, and at level 0 the Root AP allocates 1 bit in the Root beacon so that transmission is prohibited in RAW that is not explicitly assigned by the Root AP. It can indicate whether or not. In level 1, the relay allocates 1 bit in the relay beacon to indicate whether transmission is prohibited in RAW that is not explicitly assigned by the relay AP. For example, if the allocated bit is 1, the STA cannot transmit other than the period explicitly set to RAW.

In 802.11ah, an AP may implicitly indicate an interval for entering power saving. For example, if the AP Power Save bit is set to 1 in the Short Beacon, Beacon, etc., the STA may be prohibited from transmitting to the AP other than the explicitly allocated RAW period.

In Level 1, the AP Power Save bit may be used to indicate whether transmission of the STA is prohibited in a section other than the RAW section allocated by the relay. In order to prohibit transmission of the STA in a section other than the RAW section, when the relay sets the AP Power Save bit to 1 in the relay beacon, the STAs may be prohibited from transmitting in the DRAW or the RAW section. At level 0, when the Root AP sets the AP Power Saving bit to 1 in the Root beacon, transmission of an STA or Relay directly connected to the Root AP may be prohibited in a section other than RAW explicitly allocated by the Root AP. .

Table 6 below shows modified Empty RAW signaling information indicating that transmission is explicitly prohibited during a RAW period only for a specific STA.

Transmission of STAs specified in the List of Prohibited STAs is prohibited in the Empty RAW interval, and other unspecified STAs may communicate through the Empty RAW interval competition. In addition, by adding a List of Prohibited STA to the AP PM RAW of the existing 802.11ah, only transmission of STAs specified in the List of Prohibited STA may be prohibited. The above example is applicable to both (A) a method of using DRAW and (B) a method of allocating resources by using resource allocation information.

Referring to FIG. 43, the resource allocation information may be included in a separate Relay Resource Allocation IE and transmitted, and the section to which the resource is allocated may be clearly protected through Empty RAW or may be protected through an implicit method.

When transmitting between STA-Relay-Root AP in one TXOP by using TXOP Sharing, STA transmits UL data to Relay in UL slot of a specific STA among transmission periods allocated to Relay, and when slot remains Can immediately transmit UL data to the Root AP. At this time, the Root AP may set the interval allocated for the relay to Empty RAW to prevent transmission of STAs belonging to other Root APs.

In the case of DL, a Root AP transmits a DL frame for a specific STA to a Relay in a section allocated to the DL interval, and the Relay has a DL transmission slot allocated to itself by the Root AP, and the STA to receive the DL frame wakes up. If there is, the DL frame can be immediately transmitted to the STA.

As another example, the root AP may transmit a DL frame to the relay using a slot allocated to the STA to receive the DL frame from the relay. In this case, transmission of an STA belonging to another root AP can be prevented by setting the interval allocated by the root AP for relay to empty RAW. After receiving the DL frame for the STA from the Root AP, the relay may transmit the DL frame through a DL slot (a slot allocated by the Relay) for the corresponding STA.

The embodiment shown in FIG. 44 shows another example of transmitting using a relay resource allocation location IE in a single frequency subband, in which a form similar to using a DRAW is applied to resource allocation in the same manner.

Referring to FIG. 45, a root AP may independently transmit in a different frequency subband from a relay, and relays using subbands A and B may also independently transmit. Since the frequency subbands are independent of each other, the time intervals assigned to each relay at level 1 do not need to be aligned based on each other's time intervals, and do not need to be aligned with the RAW of the Root AP, as compared to the case of using DRAW. Flexible and easy to expand

23, 24, 25, 26, 27, 28, 31, and FIG. 37 described as an example of simultaneous transmission when the relay clusters are spatially separated, and simultaneous transmission in the time domain described as an example of the DRAW The resource allocation method using the resource allocation information (B) may be applied to all the embodiments of FIG. 38 described as an example of FIG.

When the relay connects to the Root AP, and negotiates with the Root AP about relay related parameters, it requests the Root AP for the Beacon Interval to be used by the Relay and the duration required for the Relay BSS transmission, and the initial relay from the Root AP. A BSS transmission interval may be allocated. After the transmission between the relay and the STA is started, the relay may determine whether more or less allocation of a transmission interval for the relay BSS is required based on the traffic transmitted from the STA and may feed back the determination result to the root AP. The Root AP may adjust the transmission interval for the Relay BSS based on the information received from the Relay and reassign it to the Relay BSS. This method can be useful when the traffic volume and period are relatively constant. If the transmission traffic and transmission period of the STA is not constant, the following method D and method E may be used to more accurately allocate the transmission period of the relay BSS.

46 illustrates an example of allocating a relay transmission interval according to an embodiment. The relay may feed back a mean data rate of the STA to the root AP before the next delivery traffic indication message (DTIM) of the relay. In the case of a target wake time (TWT) STA, target wake time information may be transmitted together with a mean data rate.

In case of implicit TWT, Wake Interval can be additionally fed back to Root AP. In this case, the Root AP may determine the next TWT by adding the Wake Interval to the previous TWT even if the Relay does not feed back the TWT every time within the range that the Wake Interval does not change as the TWT is periodically transmitted.

For example, the Root AP is sum of "(DL amount of buffered data for each STA to be set to TIM = 1 for the next traffic indication message (TIM) of the relay beacon or DTIM interval / mean data rate of each STA) ( The entire DL interval of the next TIM or DTIM interval may be determined approximately based on the sum of the amount of data buffered / mean data rate of each STA to each TWT STA having the data buffered and awakened in the next TIM or DTIM interval. .

For example, the Root AP may determine the DL Duration to be transmitted during the next Relay Beacon interval for the Relay BSS based on Equation 1 below.

Here, DataSizeBufferedForTIMSTA (i) represents the data size (bits) of the TIM STA (i) buffered in the Root AP, and MeanDLDataRateOfTIMSTA (i) represents the Mean DL Data Rate (bits / s) of the TIM STA (i). In the relay beacon, if the TIM bit for the TIM STA (i) is set to 1, the TIMbit (i) ForNextRelayBeacon) for the next relay beacon is set to 1, otherwise, the TIMbit (i) for the next relay beacon is set. ) Is set to zero.

DataSizeBufferedForTWTSTA (j) represents the data size (bits) of the TWT STA (j) buffered at the Root AP, and MeanDLDataRateOfTWTSTA (j) represents the Mean DL Data Rate (bits / s) of the TWT STA (j). If the Target Wake UP Time of the TWT STA (j) exists within the next Relay Beacon Interval, the value of WithinNextRelayBeacon (j) interval is set to 1, and otherwise, the value of WithinNextRelayBeacon (j) interval is set to 0. .

In the case of the TWT STA, the transmission interval may not be adjacent, and in this case, it is also possible to further add the time between transmission periods of the TWT STA to the DL Duration. Even if the relay performs TIM segmentation, the relay can transmit the remaining data after the next relay beacon transmission when there is not enough time for the first TIM segment transmission.

The relay may transmit the expected data amount to the Root AP based on the previous transmission statistics of UL data. In the case of a TIM STA, information of an expected data amount calculated based on a Mean Data Rate (for UL) for a relay of an STA and UL data transmission statistics of a previous STA may be needed to determine an expected data amount. In the case of the TWT STA, the TWT information needs to be additionally transmitted to the Root AP in order to determine the expected data amount. In case of Implicit TWT, Wake Interval information can be additionally transmitted to Root AP.

For example, a time interval required for transmitting UL data in the relay BSS may be determined based on Equation 2 below.

Here, MeanULDataSizeForTIMSTA (i) represents Mean UL Data Size (bits) for TIM STA (i), and MeanULDataRateOfTIMSTA (i) represents Mean UL Data Rate for TIM STA (i). MeanULDataSizeForTWTSTA (j) represents Mean UL Data Size (bits) for TWT STA (j), and MeanULDataRateOfTWTSTA (j) represents Mean UL Data Rate for TWT STA (j).

If the Target Wake UP Time of the TWT STA (j) exists within the next Relay Beacon Interval, the value of WithinNextRelayBeacon interval is 1, and in other cases, the value of WithinNextRelayBeacon interval (j) is set to 0.

In the case of the TWT STA, the transmission interval may not be adjacent, and in this case, it is also possible to further add the time between transmission periods of the TWT STA to the DL Duration.

The relay does not feed back Mean UL Data Size for TWT STA, Mean UL Data Rate for TWT STA, Mean UL Data Size for TIM STA, Mean UL Data Rate for TIM STA to Root AP, respectively (Mean UL Data Size for TWT STA The relay may directly calculate the value of) / (Mean UL Data Rate for TWT STA) and the value of (Mean UL Data Size for TIM STA) / (Mean UL Data Rate for TIM STA) to feed back to the Root AP.

For example, the expected UL duration during the next Relay beacon interval may be determined based on Equation 3 below.

Here, if the Target Wake UP Time of the TWT STA (j) exists within the next Relay Beacon Interval, the value of WithinNextRelayBeacon interval is 1, and in other cases, the value of WithinNextRelayBeacon interval (j) is set to 0.

MeanULDurationForTIMSTA (i) represents (Mean UL Data Size (bits) for TIM STA (i)) / (Mean UL Data Rate (bits / s) for TIM STA (i)). MeanULDurationForTWTSTA (j) represents (Mean UL Data Size (bits) for TWT STA (j)) / (Mean UL Data Rate (bits / s) for TWT STA (j)).

Based on the UL Duartion and DL Duration for the Relay BSS calculated as described above, the transmission interval of the entire Relay BSS can be calculated as shown in Equation 4 below.

The STA Information Announcement frame defined in 802.11ah may be extended and used. For example, an additional element of the STA Information Announcement frame may be defined to include Duration allocation related information as well as AID update information in the STA Information Announcement frame. Alternatively, a new frame that may include duration allocation related information may be defined, and the relay may transmit a newly defined frame to the root AP. The relay does not need to update all the STA information for every DTIM, and can update only the information on the STA whose data rate fluctuates.

Initially, the Root AP can allocate the transmission time and the initial transmission interval of the relay beacon based on the total number of relays in the extended BSS. The relay may transmit a relay setup request for an initial transmission duration, a relay beacon interval, etc. to the root AP. In response to the relay setup request, the root AP may transmit a relay setup response regarding a next relay target beacon transmission time (TBTT), beacon interval, and initial duration to the relay.

Regarding the update of the transmission interval, there are the following Option 1 and Option 2 methods.

(1) Option 1: If the traffic of the STA connected to the relay is regular, the Root AP allocates a transmission interval periodically and can adjust the transmission interval only when the relay explicitly requests the update of the transmission interval.

(2) Option 2: If the traffic of the STA connected to the relay is not regular, the Root AP can adjust the transmission interval based on the information on each STA of the relay. The relay can transmit information and additional information received from the STA to the Root AP using the ReachableAddressUpdate frame when the STA connects to the relay, and the Root AP can adjust the transmission interval in the relay cluster based on the information received from the Relay. . The relay may transmit information on the ReachableAddress (MAC address of the STA), the Mean Data Rate, the AID of the STA, and the STA Type to the Root AP when every STA is connected to the relay. Mean Data Rate uses the initial value (4 octet) transmitted to the relay when the STA first connects to the relay. Immediately before the DTIM transmission time of the relay, the relay may transmit information on the number of TIM segments (+ TIM Offset, Page Offset), updated mean data rate, and AID of the reassigned STA to the Root AP. . The updated mean data rate and the AID of the reassigned STA may be transmitted when necessary for each STA.

The root AP may determine when the relay DTIM is transmitted based on the relay beacon. The Root AP may determine the number of Beacons after DTIM based on the number of TIM Segments and the STA's AID to transmit a TIM Segment for a specific STA. Since the relay schedules DL transmission to the STA in the TIM segment, the Root AP can predict the transmission from the relay to the STA in the relay beacon period.

The Root AP can predict the time required for DL transmission in a specific Relay Beacon Interval based on the traffic amount for the STA, the Mean Data rate, and the Relay Beacon Interval through which DL data is transmitted. In the case of the TWT STA, the Root AP can predict the time required for DL transmission in a specific Relay Beacon Interval based on the TWT, transmission interval information, and Mean Data Rate information.

The root AP may determine the UL transmission interval based on STA type information transmitted when the STA connects to the relay. The relay can allocate the allocated transmission interval in detail to UL RAW and DL RAW. If the transmission interval is not sufficient, the Root AP, Relay, STA may transmit data in the next transmission interval after buffering the data.

The relay may initially measure the spatial separation from the other relay BSS to the root AP, and transmit the measurement result to the root AP. The root AP may allocate a transmission period of the relay BSS based on the measurement result received from the relay. If the new relay BSS and the other relay BSS are sufficiently separated from each other, the transmission interval can be overlapped.

In addition, the relay BSS explicitly clears the transmission interval of another relay BSS to empty RAW (or AP PM) in order to prevent a collision due to transmission of data in another Relay BSS transmission interval using the same channel. RAW). The relay BSS periodically determines whether there is a spatial separation from another relay BSS, and if it is not separated sufficiently, set another relay transmission interval to Empty RAW (or AP PM RAW) to perform data transmission of the STA connected to it. Can be prohibited. Alternatively, the Relay BSS does not prohibit data transmission of all STAs in the Relay BSS with respect to other Relay transmission intervals, but may also prohibit transmission only for a specific STA that is subject to much interference from other Relay BSSs among the STAs in the Relay BSS. In this case, use of a modified Empty RAW (or modified AP PM RAW) that may indicate an STA that is explicitly prohibited from transmission, or a method of excluding a STA forbidden from transmission interval allocation may be used. Can be.

Similarly, in order to prevent a collision due to the transmission of data in another Relay BSS transmission section using the same channel, the STA of the Root BSS similarly uses the Empty RAW (or AP PM) explicitly. RAW). Root BSS, similar to Relay BSS, uses the method described below to determine whether it is spatially separated from other Relay BSS, and if it is not separated enough, set another Relay transmission section to Empty RAW (or AP PM RAW) Can prohibit data transmission. Alternatively, the Root BSS does not prohibit data transmission of all STAs in the Root BSS with respect to other Relay transmission intervals, and may prohibit transmission only for a specific STA that receives much interference from other Relay BSSs among the STAs in the Root BSS. In this case, use of a modified Empty RAW (or modified AP PM RAW) that may indicate an STA that is explicitly prohibited from transmission, or a method of excluding a STA forbidden from transmission interval allocation may be used. Can be.

In the level 1 transmission, the STA may transmit a transmission interval that is not explicitly assigned to an empty relay interval even if the transmission interval is not assigned to its own relay, when no transmission of another relay BSS is detected in the interval, or the corresponding relay BSS. As a result of the determination based on the Beacon of, if the RAW is not set within the allocated interval for transmission of the corresponding relay BSS, the transmission may be exceptional.

In the level 0 transmission, even if the STA of the root BSS is a time interval allocated to another relay BSS, when the transmission of another relay BSS is not detected in the corresponding interval, or as determined based on the beacon of the corresponding relay BSS, the corresponding relay If RAW is not set within the interval allocated for the transmission of the BSS, it can be exceptionally transmitted.

The relay or the root AP may explicitly prohibit transmission of STAs connected to the self by setting an empty RAW period in which a collision or contention is expected to be severe among transmission periods not allocated to the relay or root AP. In addition, the relay AP may prohibit the STA from transmitting to the relay in the section in which the transmission between the relay and the root AP occurs by setting the empty RAW interval between the relay and the root AP. For example, a relay or a root AP may prohibit transmission of all STAs connected to a relay in a specific period by setting AP power management (PM PM) = 1. AP PM represents a parameter for adjusting a power saving mode of a station.

The first method to determine the spatial separation degree is to extend the Frame Request / Response frame defined in 802.11k to determine whether STAs in their own relay BSS are separated from the relays in the neighboring relay BSS and the STAs in the neighboring relay BSS. How to judge. FIG. 47 is a diagram illustrating a format for a frame request according to an embodiment, and FIG. 48 is a diagram illustrating a format for a frame report according to one embodiment. The STA may detect a received channel power indicator (RCPI) and a received signal to noise indicator (RSNI) regarding a transmission frame of an STA belonging to another relay BSS, and may report the detected RCPI and RSNI.

While the RCPI and RSNI values for the AP may be identified using the Beacon Report, the average RCPI and RSNI values for the STA may be identified through any frame transmission transmitted by any STA.

The Beacon Request may include a frame measurement request for an STA targeting a specific MAC address. Here, the Wildcard MAC address can be designated.

The frame report may include a frame count report subelement in an optional subelement. One report entry may include a count, average RCPI, and RSNI information about a frame transmitted from one STA. Based on the number of frames, average RCPI, and RSNI information, it may be determined how spatially separated from a specific STA.

-Extension of Frame Request / Response frame considering Relay-

49 is a diagram illustrating an example of a format of a Measurement Request field according to an embodiment, and FIG. 50 is a diagram illustrating an example of a format of a Measurement report field according to an embodiment.

In order to determine whether a particular relay and a STA are separated, a Frame Request / Response frame is extended to measure a frame transmitted from a specific BSSID or to a specific BSSID. Frame Request / Response frame is extended to add BSSID to Optional sub-element of existing format.

If the MAC address is wildcard and the BSSID is assigned to the sub-element, the Frame Request / Response frame can be extended to measure the frame transmitted from the BSSID and the frame transmitted to the BSSID.

In the extended frame request / response frame, a measurement start time may be specified in addition to the measurement duration. When requesting a frame report, it is possible to set the start point of the transmission interval allocated to the relay BSS to be measured. In order not to disturb transmission of other relays, STAs may measure only in another relay transmission interval and transmit a measurement report later. RAW may be allocated for the transmission of measurement reports.

During the transmission period of the relay BSS, the STA requests broadcast / groupcast measurement report, and the STAs supporting the 802.11k function measure the designated relay during the designated start time / transmission period and measure the relay to which they are connected. You can send the result. The relay receiving the measurement result may determine whether the relay is separated from the neighboring relay based on the measurement result.

In order to reduce the amount of traffic, a method of selecting an STA supporting any 802.11k belonging to a relay may also be used. This is because when the measurement report is received from all the STAs belonging to the relay, the traffic amount may be too large. For example, the relay may select any of the STAs supporting 802.11k and request a measurement report from the selected STA.

The relay may request an STA that performs measurement to send information such as RCPI, RSNI average value or maximum value for a specific BSS total transmission, not for each TA address. In order to reduce the reported size of the relay, the relay is the average value of RCPI, RSNI, or RCPI and RSNI for each STA, or the RCPI and RSNI value of the external STA that most affects the corresponding relay (ie, RCPI, RSNI maximum). ) Can be requested to send only STA.

A BSS Frame Count Report can be defined that transforms an existing Frame Report Entry to represent the entire BSS information. That is, by making the existing frame count report shorter, it is possible to define a BSS Frame Count Report including only the BSSID, the average transmission frame count in the BSSID, Average RCPI, and RSNI.

Each relay may request a frame report from the STAs belonging to the relay, and may measure whether the STAs are separated from the neighbor relay BSS based on the frame report. The Root AP can also request a Frame Report from STAs belonging to the Root AP, and can measure whether the STA is separated between each STA of each Root BSS and the neighboring Relay BSS.

The relay AP or the root AP may determine whether to separate the BSS from the specific relay BSS and determine whether to set the transmission interval of another relay BSS to Empty RAW. If the relay AP or the root AP determines that the BSS and the specific relay BSS are not sufficiently separated, the relay AP or the Root AP sets the transmission interval of the other relay BSS to Empty RAW or sets AP PM = 1 to the BSS in another relay transmission interval. The belonging STA may be prevented from transmitting data.

According to another embodiment, the relay AP or the root AP may identify STAs that are not sufficiently separated from other relays based on the measurement report from the STA belonging to the relay AP or the root AP. The relay AP or the root AP may prohibit transmission only for STAs that are not sufficiently separated from other relays in the transmission period of another relay. That is, the relay AP or the root AP may prohibit transmission of only some STAs that are interfered with by a specific relay BSS, not prohibit transmission of all STAs of its BSS. In this case, in order to prohibit only transmission of a specific STA in the root BSS or relay BSS, two methods may be used: (1) a method of modifying AP PM or empty RAW and (2) a method of using an existing RAW allocation. have. (1) A method of modifying and using AP PM or Empty RAW includes a (partial) AID list of STAs to be prohibited during transmission in AP PM RAW or Empty RAW, and in AP PM RAW or Empty RAW ( partial) This is a method of preventing only the STAs included in the AID list from transmitting explicitly and allowing the remaining STAs to transmit through the contention. (2) The method of using the existing RAW allocation is a method of preventing the STA from transmitting when the RAW for another Relay transmission interval is not allocated to RAW, the STA to explicitly prohibit transmission.

When a relay initially requests a BSS establishment from a Root AP, the Relay can transmit information on whether or not it is separated from a neighboring relay to the Root AP, and the Root AP sends a relay BSS that is spatially separated from each other based on the information received from the Relay. The same transmission interval can be allocated.

In addition, the relay periodically or aperiodically measures the degree of spatial separation with other relay BSS, and when the degree of spatial separation with other relay BSS changes more than a preset reference, it may feed back the changed contents to the Root AP. For example, a relay may receive a lot of interference from another relay BSS that is previously separated, or vice versa, when a new relay BSS is detected, the relay AP may be notified about this. The Root AP may allocate transmissions of newly spatially separated relays to the same section based on spatial separation information between the relays.

To reduce the size of the measurement report, a reporting option similar to the Beacon Report can be added to the Frame Request. For example, the reporting option may be set to include in the measurement report only for the specific RCPI, RSNI above or below.

The second method for determining spatial separation is to use beacon request / response defined in 802.11k. FIG. 47 is a diagram illustrating a format for a frame request according to an embodiment, and FIG. 48 is a diagram illustrating a format for a frame report according to one embodiment.

The Root AP can transmit a Beacon Request frame to the STA and Relay connected to the Root AP. The STA may request a list of APs transmitting beacons that can be received from other STAs through a beacon request / report. Since the relays use the same service set identification (SSID) as the Root AP, the Root AP may include the SSID of the Root AP in an optional sub-element for receiving a Beacon Report from a new STA. The BSSID may be set to wildcard BSSID.

The newly established relay can receive a beacon request from the root AP, measure the beacon and probe response of another relay, and transmit the measurement result to the root AP through a beacon report. The root AP may allocate a transmission interval for newly established relays based on RCPI, RSNI, etc. between newly established relays and other relay APs.

The Root AP can send a Beacon Request even after a newly established Relay, and can update the resource allocation based on the spatial separation.

After the STAs are connected to the relay BSS, each relay may randomly select some STAs among the STAs having a measurement function and may transmit a beacon request to the selected STAs. At this time, the BSSID of the Beacon Request may be set to the wildcard BSSID and the SSID of the optional subelement to the SSID of the Root AP.

The relay may set a reporting condition of the Beacon Request so that the Beacon Report is transmitted when the RCPI level, RSNI level is above or below.

The relay may determine whether or not the spatial separation between the STA and another relay is based on the beacon report received from the STAs periodically or aperiodically. When the relay determines that the STA and another relay are spatially adjacent to each other, the relay may prohibit transmission of the corresponding STA by setting the transmission time of the corresponding other relay to Empty RAW.

Each relay can determine whether the spatial separation between the STAs and the neighboring relay based on the Beacon Report received from the STAs belonging to it. Root AP can also determine whether the spatial separation between each STA directly connected to the root BSS and the peripheral relay based on the Beacon Report received from the STAs belonging to it.

The relay AP or the root AP can determine whether to spatially separate between its BSS and other relays, and determine whether to set another relay transmission interval to Empty RAW (or AP PM RAW). Relay AP or Root AP can set Empty RAW or AP PM = 1 when its BSS and other relays are not sufficiently separated spatially, so that STA belonging to its BSS in another Relay transmission interval can be set. You can prohibit this from sending.

When a relay initially requests a BSS establishment from a Root AP, the Relay can transmit information on whether or not it is separated from a neighboring relay to the Root AP, and the Root AP sends a relay BSS that is spatially separated from each other based on information received from the Relay. The same transmission interval can be allocated.

The above method of measuring the interference between the relay BSS is applicable to the method of measuring the interference between the Multi BSS in the wireless LAN as well as the relay.

Referring to FIG. 51, a relay AP (or a general AP) R1 may select STAs to perform measurement among STAs connected thereto and transmit a frame request to the selected STAs. Each STA in the R1 BSS that receives the frame request may measure separation information about the neighboring relay BSS (or general BSS) having R2 as an AP and transmit the measurement result to R1 in the form of a frame report. STAs in the R1 BSS that receive the Frame Request may measure a frame transmitted from STAs in the neighboring BSS such as R2 during the measurement time. For example, the separation information may indicate a degree of separation between the STA itself and the AP R2 or between the STA itself and the STAs connected to R2. R1 may determine the degree of interference from the surrounding BSS based on RCPI, RSNI information, etc. included in the Frame Report received from each STA.

52 is a diagram illustrating a configuration of an access point 5200 according to an embodiment.

Referring to FIG. 52, the access point 5200 may include a resource allocator 5210 and a communication unit 5220.

The resource allocator 5210 may allocate a resource for communication between the relay and the station connected to the relay. The resource allocator 5210 may allocate a transmission time or frequency subband for communication between the relay and the station connected to the relay.

The resource allocator 5210 may delegate detailed resource allocation for the stations connected to the relay to the relay. For example, the resource allocator 5210 may allocate a transmission section for communication between a relay and a station connected to the relay, and divide the transmission section allocated by the relay into detailed transmission sections for each station. The relay may allocate resources for stations included in the relay BSS.

In addition, the resource allocator 5210 may allocate a resource for communication with a station directly connected to the access point 5200 without passing through a relay. The resource allocator 5210 may control the station directly connected to the access point 5200 not to communicate during the allocated transmission time for communication between the relay and the station connected to the relay.

According to another embodiment, the resource allocator 5210 may directly allocate resources to all stations included in the root AP BSS. That is, the resource allocator 5210 may allocate resources for the station connected to the relay as well as the station directly connected to the access point 5200. For example, the resource allocator 5210 may allocate a limited access window or slot for each station included in the root AP BSS. The resource allocator 5210 is a limited access window or slot for communication between the access point 5200 and the relay, communication between the access point 5200 and the station connected to the access point 5200, as well as communication between the relay and the station connected to the relay. Can be assigned. The restricted access window or slot represents a transmission interval in the time domain, and a time domain in which communication is allowed may be determined based on the limited access window or slot. The restricted access window or slot may include a downlink transmission interval or an uplink transmission interval.

The resource allocator 5210 may allocate a resource for communication between the relay and the station connected to the relay based on the degree of spatial separation between the relays. The resource allocator 5210 may determine the degree to which the relay is spatially separated from other relays, and allocate resources based on the determination result. For example, when the resource allocator 5210 determines that the relay is separated from other relays by more than a predetermined distance spatially, the resource allocator 5210 may allocate the same or overlapping transmission intervals to the relays.

The resource allocator 5210 may allocate resources based on a frequency subband for communication between the relay and a station connected to the relay, and a frequency subband for communication between the access point 5200 and the relay. For example, the resource allocator 5210 may perform both communications if the frequency subband used for communication between the relay and the station connected to the relay and the frequency subband used for communication between the access point 5200 and the relay do not overlap. The same or overlapping transmission intervals may be allocated.

The communicator 5220 may transmit resource allocation information about a resource allocated by the resource allocator 5210 to the relay. The communication unit 5220 may transmit resource allocation information to the relay for information on allocation of resources for communication between the relay and the station connected to the relay. For example, the resource allocation information may include transmission section information for communication between a relay and a station connected to the relay, allocated frequency subband information, information about an assigned channel, or information about a relay or station for which communication is prohibited in a specific section. It may include. Resource allocation information may be transmitted in the form of Resource Allocation IE. The resource allocation information may be displayed on the basis of identification information of the relay, frequency subbands, or time intervals. The communicator 5220 may periodically transmit a beacon including resource allocation information periodically or aperiodically.

The resource allocator 5210 may adjust an already allocated resource based on the interference information or the station information received from the relay. The station information may include information about a data rate used for communication between the station and the relay, or the size of data transmitted between the station and the relay. The communication unit 5220 may transmit information about the adjusted resource to the relay.

The relay may transmit power save poll (PS-Poll) information and uplink data indication (UDI) information received from the station to the access point 5200. The resource allocator 5210 may adjust the allocated limited access window or slot based on the PS-Poll information and the UDI information received from the relay. The UDI information may include data amount information that the station transmits to the relay. The PS-Poll information indicates information transmitted to the relay or the access point 5200 to receive a buffered frame during the power saving mode after the station is released from the power saving mode.

53 is a diagram illustrating a configuration of a relay 5300 according to an embodiment.

Referring to FIG. 53, the relay 5300 may include a resource allocator 5310 and a communication unit 5320.

The resource allocator 5310 may allocate a resource for communication between the relay 5300 and a station connected to the relay 5300 based on the resource allocation information received from the access point. For example, the resource allocator 5310 is configured to communicate with the station based on channel condition information, Modulation and Coding Schemes (MCS) information supported by the station, available frequency subband information, or the number of antennas of the station. You can assign a connection window or slot.

The resource allocator 5310 may allocate a limited access window or slot for communication between the relay 5300 and the station connected to the relay 5300 based on the resource allocation information. For example, the resource allocation information may include a transmission interval for communication between the relay 5300 and a station connected to the relay 5300, and the resource allocation unit 5310 may identify each transmission interval identified from the resource allocation information. It can be divided into detailed limited access windows for stations.

The resource allocator 5310 may prohibit transmission of all stations or some stations connected to the relay 5300 in a transmission interval allocated to another relay BSS when it interferes with another relay BSS connected to the relay 5300. have. For example, the resource allocator 5310 may empty some of the communication intervals to prevent a station connected to its relay 5300 from communicating in the communication interval between the access point and the station directly connected to the access point and the communication interval of another relay. Or AP PM RAW).

The relay 5300 may transmit a measurement request to the station to measure a frame transmitted from a specific basic service set identification (BSSID) or a frame transmitted to a specific BSSID. The station may send a measurement report to the relay 5300 in response to the measurement request. The measurement report may include information about a frame transmitted from a specific BSSID or a frame transmitted to a specific BSSID. For example, measurement reports can include received channel power indicators (RCPIs) and received signal to noise indicators (RSPI) for the number of frames transmitted from another relay, the number of frames transmitted to another relay, or the transmission frame of a station connected to another relay. It may contain information about. The resource allocator 5310 may determine whether to spatially separate from the other relay based on the measurement report received from the station, and allocate a resource for the station based on the determination result.

The communicator 5320 may receive resource allocation information from the access point. The communicator 5320 may transmit information about a resource allocated by the resource allocator 5310 to the station. The communicator 5320 may transmit a beacon including information about the allocated resource to the station periodically or aperiodically. For example, the communication unit 5320 may transmit a beacon at the start of the relay transmission interval indicated in the resource allocation information.

The beacon may include information about a restricted access window or slot for communication between the relay 5300 and a station connected to the relay 5300. The beacon transmitted by the communication unit 5320 may not include information regarding a limited access window or slot for communication between the access point and the relay 5300. The communicator 5320 may transmit station information about a station connected to the relay 5300 to the access point.

54 is a diagram illustrating a configuration of a station 5400 according to an embodiment.

Referring to FIG. 54, the station 5400 may include a controller 5410 and a communicator 5520.

The communicator 5520 may receive a beacon from the relay, and the controller 5410 may identify a resource allocated to the station 5400 based on the beacon received from the relay. The beacon received from the relay may include information about resources allocated by the relay.

The controller 5410 may identify, from the beacon received from the relay, the limited access window or the slot indicating the communication section in the time domain and the information about the frequency subband indicating the communication section in the frequency domain.

The communicator 5520 may communicate with the relay based on the identified resource. The communicator 5520 may communicate with the relay based on the identified restricted access window or slot, frequency subband. For example, the communication unit 5520 may receive data from a relay in a RAW section in which downlink transmission is allowed, and transmit data to the relay in a RAW section in which uplink transmission is allowed.

In step 5510, the access point may allocate resources for communication between the access point and the relay, and for communication between the access point and a station connected to the access point. The access point may allocate a limited access window or slot for communication between the access point and the relay and between the access point and the station connected to the access point. The restricted access window or slot may determine the time domain in which communication is allowed. The restricted access window or slot may include a downlink transmission interval and an uplink transmission interval.

At step 5520, the access point may allocate a second resource for communication between the relay and the station connected to the relay. The access point may allocate at least one of a transmission time and a frequency subband for communication between the relay and the station connected to the relay. The access point may allocate a limited access window or slot for communication between the relay and the stations connected to the relay.

In step 5530, the access point may transmit resource allocation information about the allocated second resource to the relay. The resource allocation information includes identification information of a relay, a transmission allowable start time, a transmission interval, a period in which resources are allocated, an allocated channel, an assigned frequency subband, or a relay or station for which communication is prohibited in a specific transmission interval. can do. For example, the identification information of the relay may include an Allocation Identifier (AID), partial AID, or partial BSSID of the relay. The access point may transmit a beacon to the relay that includes information about the allocated first resource and the allocated second resource.

At step 5540, the access point may adjust the allocated second resource based on the interference information or station information received from the relay. The station information may include information regarding at least one of a data rate used for communication between a relay and a station connected to the relay, and a size of data transmitted between the relay and the station connected to the relay.

Alternatively, the access point may adjust resources allocated for communication between the relay and the station connected to the relay based on power saving survey information and uplink data indication information of the station received from the relay.

In step 5610, the relay may receive resource allocation information from the access point. The resource allocation information may include information on at least one of a transmission interval, a usable frequency subband, and an available channel for communication between the relay and the station connected to the relay.

In step 5620, the relay may allocate resources for communication between the relay and a station connected to the relay based on the resource allocation information. The relay may allocate a limited access window or slot for communication between the relay and a station connected to the relay based on the resource allocation information. The restricted access window or slot may determine the time domain in which communication between the relay and the station is allowed.

According to another embodiment, the relay may request the station to measure the number of frames transmitted from another relay, the number of frames transmitted to another relay, or the RCPI and RSNI for the transmission frame of the station connected to the other relay. The station may send a measurement report to the relay in response to the measurement request. The relay may determine whether it is spatially separated from other relays based on the measurement report received from the station, and may allocate resources for communication between the relay and the station connected to the relay based on the determination result.

At step 5630, the relay may transmit a beacon to the station that includes information about the allocated resource. The relay may send beacons to the station periodically or aperiodically. The beacon may include information about a restricted access window or slot for communication between the relay and a station connected to the relay. The beacons transmitted by the relays may not include information about restricted access windows or slots for communication between the access point and the relays.

In step 5710, the station may identify the resource allocated to the station based on the beacon received from the relay. The beacon received from the relay may include information about resources allocated by the relay. The station may identify information about at least one of the restricted access window, slots, and frequency subbands from the beacon.

At step 5720, the station may communicate with the relay based on the identified resource. The station may communicate with the relay based on a limited access window or slot, frequency subbands. For example, the station may receive data from a relay in a RAW period in which downlink transmission is allowed, and transmit data to the relay in a RAW period in which uplink transmission is allowed.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, or the components of the described system, structure, device, circuit, etc. may be combined or combined in a different form from the described method, or other components or equivalents. Appropriate results can be achieved even if replaced or substituted by water.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims

In a wireless LAN system including an access point (AP), a relay, and a station, a resource allocation method performed by the access point includes:

Allocating a first resource for communication between the access point and the relay and communication between the access point and a station associated with the access point; And

Allocating a second resource for communication between the relay and a station connected to the relay

Resource allocation method comprising a.
The method of claim 1,

Allocating the second resource,

Allocating at least one of a transmission period and a frequency subband for communication between the relay and a station connected to the relay

Resource allocation method comprising a.
The method of claim 1,

Transmitting resource allocation information about the allocated second resource to the relay;

The resource allocation method further comprises.
The method of claim 3,

The resource allocation information,

And identification information of the relay, transmission allowable start time, transmission interval, resource allocation period, allocated frequency subband, and information on at least one of a relay or a station for which communication is prohibited in a specific transmission interval. Resource allocation method.
The method of claim 1,

Adjusting the allocated second resource based on the interference information received from the relay;

The resource allocation method further comprises.
The method of claim 1,

Adjusting the allocated second resource based on the station information received from the relay

More,

The station information,

And at least one of a data rate used for communication between a relay and a station connected to the relay, and at least one of a size of data transmitted between the relay and a station connected to the relay.
The method of claim 1,

The second resource,

And assigning by the relay a restricted access window or a slot for communication between the relay and a station connected to the relay.
The method of claim 7, wherein

The limited access window or slot,

A resource allocation method comprising a downlink transmission period or an uplink transmission period.
The method of claim 7, wherein

The limited access window or slot,

Determining a time domain in which communication is allowed.
The method of claim 1,

Based on the power save poll (PS-Poll) information and uplink data indication (UDI) information of the station received from the relay is allocated for communication between the relay and the station connected to the relay Steps to tune your resources

The resource allocation method further comprises.
The method of claim 1,

Allocating the first resource,

Allocating a restricted access window or slot for communication between the access point and the relay, and communication between the access point and a station connected to the access point,

Allocating the second resource,

Allocating a restricted access window or slot for communication between the relay and a station connected to the relay.
The method of claim 1,

Transmitting a beacon including information about the allocated first resource and the allocated second resource to the relay;

The resource allocation method further comprises.
In a WLAN system including an access point, a relay, and a station, a resource allocation method performed by the relay may include:

Receiving resource allocation information from the access point; And

Allocating resources for communication between the relay and a station connected to the relay based on the received resource allocation information;

Resource allocation method comprising a.
The method of claim 13,

Allocating the resource,

Allocating a restricted access window or slot for communication between the relay and a station connected to the relay based on the received resource allocation information;

Resource allocation method comprising a.
The method of claim 13,

Allocating the resource,

Determining spatial separation from other relays based on a measurement report received from the station; And

Allocating resources for communication between the relay and the station connected to the relay based on the determination result;

The measurement report may include a number of frames transmitted from the other relay, a number of frames transmitted to the other relay, a received channel power indicator (RCPI) and a received signal to noise indicator (RSNI) related to a transmission frame of a station connected to the other relay. Resource allocation method comprising the information on at least one of.
The method of claim 13,

The resource allocation information,

And identification information of the relay, transmission allowable start time, transmission interval, resource allocation period, allocated frequency subband, and information on at least one of a relay or a station for which communication is prohibited in a specific transmission interval. Resource allocation method.
The method of claim 13,

Transmitting a beacon to the station including information about the allocated resource;

The resource allocation method further comprises.
In a WLAN system including an access point, a relay, and a station, the communication method performed by the station includes:

Identifying resources allocated to the station based on the beacons received from the relays; And

Communicating with the relay based on the identified resource,

The beacon, the communication method characterized in that it comprises information about the resources allocated by the relay.
The method of claim 18,

The identifying step,

Identifying at least one of a restricted access window, a slot, and a frequency subband from the beacon

Communication method comprising a.
An access point for allocating resources for communication between a relay and a station connected to the relay;

A relay for allocating a restricted access window or slot for communication with the station based on the allocated resources; And

A station communicating with the relay based on the assigned restricted access window or slot

Wireless LAN system comprising a.
The method of claim 20,

The access point is,

And at least one of a transmission period and a frequency subband for communication between a relay and a station connected to the relay.
The method of claim 20,

The access point is,

And transmitting resource allocation information indicating the allocation of resources for communication between the relay and the station connected to the relay to the relay.
The method of claim 22,

The resource allocation information,

And identification information of the relay, transmission allowable start time, transmission interval, resource allocation period, allocated frequency subband, and information on at least one of a relay and a station for which communication is prohibited in a specific transmission interval. WLAN system.
The method of claim 20,

The access point is,

And allocating the resource based on a frequency subband for communication between a relay and a station connected to the relay, and a frequency subband for communication between an access point and the relay.
The method of claim 20,

The access point is,

And controlling a station connected directly to the access point to communicate during the allocated transmission time.
The method of claim 20,

The access point is,

And determining the degree of spatial separation of the relay from other relays, and allocating resources for communication between the relay and the station connected to the relay based on the determination result.
The method of claim 20,

The access point is,

And adjusting the allocated resource based on the interference information received from the relay.
The method of claim 20,

The relay,

Transmit station information about the station connected to the relay to the access point,

The access point is,

And a resource for communication between the relay and the station based on the station information received from the relay.
The method of claim 28,

The station information,

And at least one of a data rate used for communication between the station and the relay and a size of data transmitted between the station and the relay.
The method of claim 20,

The access point is,

And adjusting resources allocated for communication between the relay and the station connected to the relay based on power saving survey information and uplink data indication information of the station received from the relay.
The method of claim 20,

The relay,

Allocating an access window or slot for communication with the station based on at least one of channel condition information, Modulation and Coding Schemes (MCS) supported by the station, available frequency subbands, and the number of antennas of the station Wireless LAN system, characterized in that.
The method of claim 20,

The relay,

And controlling the station so that the station connected to the relay does not communicate in a communication section between the access point and a station directly connected to the access point and a communication section of another relay.
The method of claim 20,

The relay,

And transmitting a beacon including information about the assigned restricted access window or slot to the station.
A resource allocator for allocating resources for communication between a relay and a station connected to the relay; And

Communication unit for transmitting the resource allocation information about the allocated resources to the relay

Access point comprising a.
The method of claim 34, wherein

The resource allocation unit,

Allocating at least one of a transmission time and a frequency subband for communication between a relay and a station connected to the relay.
The method of claim 34, wherein

The resource allocation unit,

Adjust the allocated resource based on the interference information or the station information received from the relay,

The communication unit,

And transmit information about the adjusted resource to the relay.
The method of claim 34, wherein

The resource allocation information,

And is displayed based on at least one of identification information, a frequency subband, and a time interval of the relay.
A resource allocator for allocating resources for communication between the relay and the station connected to the relay based on the resource allocation information received from the access point; And

Communication unit for transmitting the information about the allocated resources to the station

Relay comprising a.
The method of claim 38,

The resource allocation information,

And at least one of a transmission interval, a usable frequency subband, and an available channel for communication between the relay and the station connected to the relay.
The method of claim 38,

The resource allocation unit,

And a limited access window or slot for communication between the relay and the station connected to the relay based on the received resource allocation information.
A controller for identifying a resource allocated to a station based on a beacon received from the relay; And

A communication unit communicating with the relay based on the identified resource

Station comprising a.
The method of claim 41, wherein

The control unit,

Identify from said beacon information about at least one of a restricted access window, a slot, and a frequency subband.