WO2016056685A1

WO2016056685A1 - Method and apparatus for transmitting uplink of terminal in heterogeneous network system

Info

Publication number: WO2016056685A1
Application number: PCT/KR2014/009408
Authority: WO
Inventors: 최혜영; 조희정; 고현수; 변일무; 박경민
Original assignee: 엘지전자 주식회사
Priority date: 2014-10-07
Filing date: 2014-10-07
Publication date: 2016-04-14

Abstract

Disclosed are a method and an apparatus for transmitting an uplink of a terminal in a heterogeneous network system. A method for an STA transmitting an uplink may comprise the steps of: the STA receiving, from an AP, a first scanning frame; the STA transmitting an uplink data indication message to a cellular network object, through a cellular network, based on polling indication information of the first scanning frame; the STA receiving, from the AP, a second scanning frame; and the STA transmitting an uplink frame, based on coordinated channel access parameters included in the second scanning frame.

Description

Method and device for uplink transmission of user equipment in heterogeneous network system

The present invention relates to wireless communication, and more particularly, to a method and apparatus for uplink transmission of a terminal in a heterogeneous network system.

Recently, LTE-A based communication service can provide users with much faster speed than wired internet. Accordingly, the spread of user equipment that can receive IP-based services based on cellular networks such as LTE-A is increasing. The user is using IP (Internet Protocol) based services such as Voice over LTE (VoLTE) and video call through the user terminal. Recently, the proportion of LTE-A based wireless Internet services is expected to increase further.

In addition to LTE or LTE-A, wireless local area networks (WLANs), mobile World Interoperability for Microwave Access (WiMAX), and High Speed Downlink Packet Access (HSDPA), which vary in transmission speed, coverage per base station, mobility, and data usage costs. Various communication systems can be used as next generation mobile communication networks. That is, a plurality of radio access technologies (RATs) coexist and the user may select and access a network according to his or her preference or a surrounding communication environment.

Specifically, current mobile devices such as smart phones and smart pads have a long term evolution-advanced (LTE-A) and a wireless local area network (WLAN) interface at the same time. In addition, mobile carriers support wireless Internet services through Wi-Fi zones as well as 4G networks with wide coverage.

In providing a service to a terminal through the cellular network and the WLAN network, various parts such as handover and data offloading should be considered.

An object of the present invention is to provide an uplink transmission method of a terminal in a heterogeneous network system.

Still another object of the present invention is to provide an apparatus for performing uplink transmission of a terminal in a heterogeneous network system.

According to an aspect of the present invention, there is provided an uplink transmission method of an STA, in which an STA receives a first scanning frame from an access point (AP), wherein the STA receives the first scanning frame. Transmitting an uplink data indication message to a cellular network entity through a cellular network based on polling indication information of the scanning frame, the STA receiving a second scanning frame from the AP, and the STA receiving the second scanning frame The method may include transmitting an uplink frame based on the adjusted channel access parameter included in the polling information, wherein the polling indication information includes information indicating support of polling based on the cellular network, and the uplink data indication. The message includes information on the uplink frame, and the adjusted channel access parameter is uplink. Based on the uplink data indication message received from the cellular network entity it may be determined by the AP.

According to another aspect of the present invention for achieving the above object of the present invention, an STA (station) for performing uplink transmission may be configured to be capable of dynamically communicating with an RF (radio frequency) unit for transmitting or receiving a radio signal ( and a processor that is operatively connected, wherein the processor receives a first scanning frame from an access point and transmits an uplink data indication message through a cellular network based on polling indication information of the first scanning frame. Transmit to a cellular network entity, receive a second scanning frame from the AP, and transmit an uplink frame based on the adjusted channel access parameter included in the second scanning frame, wherein the polling indication information is The uplink data indication mesh, including information indicating support of the cellular network based polling; The uplink frame may include information about the uplink frame, and the adjusted channel access parameter may be determined by the AP based on the uplink data indication message received from the cellular network entity.

The uplink transmission efficiency of a terminal that transmits or receives data based on a plurality of radio access technologies (RATs) may be improved. In addition, in the case of a terminal that fails to transmit, the transmission priority may be increased and scheduled.

1 is a conceptual diagram illustrating a structure of a wireless local area network (WLAN).

2 is a diagram illustrating a layer architecture of a WLAN system supported by IEEE 802.11.

3 is a conceptual diagram illustrating a scanning method in a WLAN.

4 is a conceptual diagram illustrating an authentication procedure and a combined procedure performed after a scanning procedure of an AP and an STA.

5 is a conceptual diagram illustrating an active scanning procedure.

6 is a conceptual diagram illustrating uplink resource allocation based on RAW according to an embodiment of the present invention.

7 is a conceptual diagram illustrating a method for transmitting and / or receiving data based on a heterogeneous network system.

8 is a conceptual diagram illustrating interworking between a WLAN and a cellular network according to an embodiment of the present invention.

9 is a conceptual diagram illustrating a method of managing AP information according to an embodiment of the present invention.

10 is a flowchart illustrating a WLAN polling operation based on a cellular network according to an embodiment of the present invention.

11 is a block diagram illustrating a wireless device to which an embodiment of the present invention can be applied.

1 shows the structure of an infrastructure BSS (Basic Service Set) of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to the top of FIG. 1, the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area. The BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.

The BSS may include at least one STA, APs 125 and 130 that provide a distribution service, and a distribution system DS that connects a plurality of APs.

The distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set. The ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110. APs included in one ESS 140 may have the same service set identification (SSID).

The portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In the BSS as shown in the upper part of FIG. 1, a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130. A network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

1 is a conceptual diagram illustrating an IBSS.

Referring to the bottom of FIG. 1, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).

A STA is any functional medium that includes a medium access control (MAC) and physical layer interface to a wireless medium that conforms to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. May be used to mean both an AP and a non-AP STA (Non-AP Station).

The STA may include a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit ( It may also be called various names such as a mobile subscriber unit or simply a user.

2 conceptually illustrates a PHY architecture of a WLAN system.

The hierarchical architecture of the WLAN system may include a medium access control (MAC) sublayer 220, a physical layer convergence procedure (PLCP) sublayer 210, and a physical medium dependent (PMD) sublayer 200. have. The PLCP sublayer 210 is implemented such that the MAC sublayer 220 can operate with a minimum dependency on the PMD sublayer 200. The PMD sublayer 200 may serve as a transmission interface for transmitting and receiving data between a plurality of STAs.

The MAC sublayer 220, the PLCP sublayer 210, and the PMD sublayer 200 may conceptually include a management entity.

The management unit of the MAC sublayer 220 is referred to as a MAC Layer Management Entity (MLME) 225, and the management unit of the physical layer is referred to as a PHY Layer Management Entity (PLME) 215. Such management units may provide an interface on which layer management operations are performed. The PLME 215 may be connected to the MLME 225 to perform management operations of the PLCP sublayer 210 and the PMD sublayer 200, and the MLME 225 may also be connected to the PLME 215 and connected to the MAC. A management operation of the sublayer 220 may be performed.

In order for the correct MAC layer operation to be performed, there may be an STA management entity (SME) 250. SME 250 may operate as a component independent of the layer. The MLME, PLME, and SME may transmit and receive information between mutual components based on primitives.

The operation of each sub-layer is briefly described as follows. The PLCP sublayer 110 may convert the MAC Protocol Data Unit (MPDU) received from the MAC sublayer 220 according to the indication of the MAC layer between the MAC sublayer 220 and the PMD sublayer 200. Or a frame coming from the PMD sublayer 200 to the MAC sublayer 220. The PMD sublayer 200 may be a PLCP lower layer to perform data transmission and reception between a plurality of STAs over a wireless medium. The MAC protocol data unit (MPDU) delivered by the MAC sublayer 220 is called a physical service data unit (PSDU) in the PLCP sublayer 210. The MPDU is similar to the PSDU. However, when an A-MPDU (aggregated MPDU) that aggregates a plurality of MPDUs is delivered, the individual MPDUs and the PSDUs may be different from each other.

The PLCP sublayer 210 adds an additional field including information required by the physical layer transceiver in the process of receiving the PSDU from the MAC sublayer 220 to the PMD sublayer 200. In this case, the added field may include a PLCP preamble, a PLCP header, and tail bits required to return the convolutional encoder to a zero state in the PSDU. The PLCP preamble may serve to prepare the receiver for synchronization and antenna diversity before the PSDU is transmitted. The data field may include a coded sequence encoded with a padding bits, a service field including a bit sequence for initializing a scraper, and a bit sequence appended with tail bits in the PSDU. In this case, the encoding scheme may be selected from either binary convolutional coding (BCC) encoding or low density parity check (LDPC) encoding according to the encoding scheme supported by the STA receiving the PPDU. The PLCP header may include a field including information on a PLC Protocol Data Unit (PPDU) to be transmitted.

The PLCP sublayer 210 adds the above-described fields to the PSDU, generates a PPDU (PLCP Protocol Data Unit), and transmits it to the receiving station via the PMD sublayer 200, and the receiving station receives the PPDU to receive the PLCP preamble and PLCP. Obtain and restore information necessary for data restoration from the header.

3 is a conceptual diagram illustrating a scanning method in a WLAN.

Referring to FIG. 3, a scanning method may be classified into passive scanning 300 and active scanning 350.

Referring to the left side of FIG. 3, the passive scanning 300 may be performed by the beacon frame 330 periodically broadcasted by the AP 300. The AP 300 of the WLAN broadcasts the beacon frame 330 to the non-AP STA 340 every specific period (for example, 100 msec). The beacon frame 330 may include information about the current network. The non-AP STA 340 receives the beacon frame 330 that is periodically broadcast to receive the network information to perform scanning for the AP 310 and the channel to perform the authentication / association (authentication / association) process Can be.

The passive scanning method 300 only needs to receive the beacon frame 330 transmitted from the AP 310 without the need for the non-AP STA 340 to transmit the frame. Thus, passive scanning 300 has the advantage that the overall overhead incurred by the transmission / reception of data in the network is small. However, since scanning can be performed manually in proportion to the period of the beacon frame 330, the time taken to perform scanning is relatively increased compared to the active scanning method. For a detailed description of the beacon frame, see IEEE Draft P802.11-REVmb ™ / D12, November 2011 'IEEE Standard for Information Technology Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications (hereinafter referred to as IEEE 802.11) 'are described in 8.3.3.2 beacon frame. IEEE 802.11 ai may additionally use other formats of beacon frames, and these beacon frames may be referred to as fast initial link setup (FILS) beacon frames. In addition, a measurement pilot frame may be used in a scanning procedure as a frame including only some information of a beacon frame. Measurement pilot frames are disclosed in the IEEE 802.11 8.5.8.3 measurement pilot format.

In addition, a FILS discovery frame may be defined. The FILS discovery frame is a frame transmitted between transmission periods of a beacon frame at each AP and may be a frame transmitted with a shorter period than the beacon frame. That is, the FILS discovery frame is a frame transmitted with a period smaller than the transmission period of the beacon frame. The FILS discovery frame may include identifier information (SSID, BSSID) of the AP transmitting the detection frame. The FILS discovery frame may be transmitted before the beacon frame is transmitted to the STA to allow the STA to detect in advance that the AP exists in the corresponding channel. The interval at which a FILS discovery frame is transmitted from one AP is called a FILS discovery frame transmission interval. The FILS discovery frame may include part of information included in the beacon frame and be transmitted.

Referring to the right side of FIG. 3, in the active scanning 350, the non-AP STA 390 may transmit the probe request frame 370 to the AP 360 to proactively perform scanning.

After receiving the probe request frame 370 from the non-AP STA 390, the AP 360 waits for a random time to prevent frame collision, and then includes network information in the probe response frame 380. may transmit to the non-AP STA 390. The non-AP STA 390 may obtain network information based on the received probe response frame 380 and stop the scanning process.

In the case of the active scanning 350, since the non-AP STA 390 performs the scanning, the time used for scanning is short. However, since the non-AP STA 390 needs to transmit the probe request frame 370, network overhead for frame transmission and reception increases. The probe request frame 370 is disclosed in IEEE 802.11 8.3.3.9 and the probe response frame 380 is disclosed in IEEE 802.11 8.3.3.10.

After scanning, the AP and the non-AP STA may perform an authentication procedure and an association procedure.

Referring to FIG. 4, after performing passive / active scanning, an authentication procedure and a combining procedure with one of the scanned APs may be performed.

Authentication and association procedures can be performed, for example, via two-way handshaking. The left side of FIG. 4 is a conceptual diagram illustrating an authentication and combining procedure after passive scanning, and the right side of FIG. 4 is a conceptual diagram showing an authentication and combining procedure after active scanning.

The authentication procedure and association procedure are based on an authentication request frame (410) / authentication response frame (420) and an association request frame (430), regardless of whether active scanning or passive scanning is used. ) / Association response frame 440 may be equally performed by exchanging an association response frame 440 between the

AP

400, 450 and the

non-AP STA

405, 455.

In the authentication procedure, the

non-AP STAs

405 and 455 may transmit the authentication request frame 410 to the

APs

400 and 450. The

AP

400 or 450 may transmit the authentication response frame 420 to the

non-AP STAs

405 and 455 in response to the authentication request frame 410. Authentication frame format is disclosed in IEEE 802.11 8.3.3.11.

In the association procedure, the

non-AP STAs

405 and 455 may transmit an association request frame 430 to the

APs

400 and 405. In response to the association request frame 430, the

APs

405 and 455 may transmit the association response frame 440 to the

non-AP STAs

400 and 450. The association request frame 430 transmitted to the AP includes information on the capabilities of the

non-AP STAs

405 and 455. Based on the performance information of the

non-AP STAs

405 and 455, the APs 400 and 350 may determine whether support for the

non-AP STAs

405 and 455 is possible. When support for the

non-AP STAs

405 and 455 is available, the APs 300 and 450 may transmit the combined response frame 440 to the

non-AP STAs

405 and 455. The association response frame 440 may include whether to accept the association request frame 440, a reason thereof, and capability information supported by the association response frame 440. Association frame format is disclosed in IEEE 802.11 8.3.3.5/8.3.3.6.

After the association procedure is performed between the AP and the non-AP STA, normal data transmission and reception may be performed between the AP and the non-AP STA. If the association procedure between the AP and the non-AP STA fails, the association procedure with the AP may be performed again or the association procedure with another AP may be performed again based on the reason for the association failure.

5 is a conceptual diagram illustrating an active scanning procedure.

Referring to FIG. 5, the active scanning procedure may be performed by the following steps.

(1) The STA 500 determines whether it is ready to perform a scanning procedure.

For example, the STA 500 may perform active scanning by waiting until the probe delay time expires or when specific signaling information (eg, PHY-RXSTART.indication primitive) is received. have.

The probe delay time may be a delay generated before the STA 500 transmits the probe request frame 510 when performing the active scanning. PHY-RXSTART.indication primitive is a signal transmitted from a physical (PHY) layer to a local medium access control (MAC) layer. The PHY-RXSTART.indication primitive may signal to the MAC layer that it has received a PLC protocol data unit (PPDU) including a valid PLCP header in a physical layer convergence protocol (PLCP).

(2) Perform basic access.

In the 802.11 MAC layer, a wireless medium may be allocated to a plurality of STAs using a distributed coordination function (DCF), which is a contention-based function. The DCF can prevent outgoing between STAs through a carrier sense multiple access / collision avoidance (CSMA / CA) based back-off procedure. The STA 500 may transmit the probe request frame 510 to the

APs

560 and 570 using a basic access method.

(3) The STA 500 may identify the AP 1 560 and the AP 2 570 included in the MLME-SCAN.request primitive (for example, service set identification (SSID) and basic service set identification). Information)) to generate the probe request frame 510.

The BSSID is an indicator for specifying the AP and may have a value corresponding to the MAC address of the AP. The SSID is a network name for specifying an AP that can be read by a person operating the STA. The BSSID and / or SSID may be used to specify the AP.

The STA 500 may transmit a probe request frame to the specified AP 1 560 and the AP 2 570. The AP1 560 and the AP2 570 that receive the probe request frame 510 may transmit the probe response frames 550 and 550 to the STA 500.

The STA 500 may unicast, multicast, or broadcast the probe request frame 510 by transmitting the SSID and the BSSID information in the probe request frame 510. For example, when the SSID list is included in the MLME-SCAN.request primitive, the STA 500 may include the SSID list in the probe request frame 510 and transmit the SSID list. The

AP

560, 570 receives the probe request frame 510 and whether to transmit the probe response frames 550, 550 to the STA 500 based on the SSID list included in the received probe request frame 510. You can decide.

(4) Reset the probe timer to 0 and start the timer.

The probe timer may be used to check the minimum channel time (MinChanneltime, 520) and the maximum channel time (MaxChanneltime, 530). The minimum channel time 520 and the maximum channel time 530 may be used to control the active scanning operation of the STA 500.

The minimum channel time 520 may be used for an operation for changing a channel performing active scanning of the STA 500. For example, if the STA 500 does not detect transmission of another frame (eg, probe response frames 550, 550) until the probe timer reaches the minimum channel time 520, the STA 500 does not detect the STA 500. ) May move the scanning channel to perform scanning on another channel. When the STA 500 detects transmission of another frame until the probe timer reaches the minimum channel time 520, the STA 500 may monitor the channel until the probe timer reaches the maximum channel time 530. When the probe timer reaches the maximum channel time 530, the STA may process the received probe response frames 540 and 550.

The STA 500 searches for the PHY-CCA. Indication primitive until the probe timer reaches the minimum channel time 520 to determine whether there is a frame received through the channel until the minimum channel time 520. You can judge.

The PHY-CCA. Indication primitive may transmit information about the state of the medium from the physical layer to the MAC layer. The PHY-CCA. Indication primitive may inform the STA 500 of the current channel state by using a channel state parameter of busy if the channel is not available and idle if the channel is available. When the PHY-CCA. Indication primitive is detected as busy, the STA 500 determines that there are probe response frames 550 and 550 received by the STA 500 and the PHY-CCA. Indication primitive is idle. If the search is idle, it may be determined that the probe response frames 550 and 550 received by the STA 500 do not exist.

If the PHY-CCA. Indication primitive is searched for idle, the STA 500 may set the net allocation vector (NAV) to 0 and scan the next channel. If the PHY-CCA. Indication primitive is detected as busy, the STA 500 may perform processing on the received probe response frames 550 and 550 after the probe timer reaches the maximum channel time 530. Can be. The STA may set the net allocation vector (NAV) to 0 after processing the received probe response frames 550 and 550 and scan the next channel.

(5) When all channels included in the channel list are scanned, the MLME may signal the MLME-SCAN.confirm primitive. The MLME-SCAN.Confirm primitive may include a BSSDescriptionSet containing all the information obtained in the scanning process.

When the STA 500 uses the active scanning method, it is necessary to perform monitoring to determine whether the parameter of the PHY-CCA. Indication primitive is busy until the probe timer reaches the minimum channel time.

Specific information included in the aforementioned MLME-SCAN. Request primitive is as follows. The STA may receive the MLME-SCAN.Request primitive in the MLME in order to perform scanning. The MLME-SCAN.Request primitive is a primitive generated by the SME. The MLME-SCAN.Request primitive may be used to determine whether there is another BSS to which the STA will bind.

The MLME-SCAN.Request primitive may specifically include information such as BSSType, BSSID, SSID, ScanType, ProbeDelay, ChannelList, MinChannelTime, MaxChannelTime, RequestInformation, SSID List, ChannelUsage, AccessNetworkType, HESSID, MeshID, VendorSpecificInfo. For a detailed description of the MLME-SCAN.Request primitive, see IEEE Draft P802.11-REVmb ™ / D12, November 2011, 'IEEE Standard for Information Technology Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific'. requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications' 6.3.3.2 MLME-SCAN.request.

Referring to FIG. 6, a restricted access window (RAW) may distinguish uplink time resources for media access. The AP may allocate RAW for channel access of the STA group or STA within the interval of the beacon frame.

The beacon frame 600 may transmit TIMs for a plurality of STAs. Bit value 1 of the TIM may indicate the existence of a downlink frame to be received from the AP. When each bitmap '01111' of the TIM corresponds to STA1 to STA5 having an AID of 1 to 5 in order, the TIM may indicate to STA2 to STA5 that there is a downlink frame to be received from the AP.

In RAW1, transmission of the PS-poll frame 620 and / or uplink data indicator (UDI) 610 of STAs based on the TIM may be performed. If the STA is instructed to exist the downlink data based on the TIM, the STA may request the downlink data from the AP by transmitting the PS-poll frame 620 to the AP. UDI 610 may be used to indicate that there is an uplink frame to be transmitted from the STA to the AP. For example, an STA having an uplink frame to be transmitted to the AP may transmit a PS-poll frame having a UDI field set to 1 to the AP.

For example, STA1 may not have a downlink frame to receive from the AP, but there may be an uplink frame to be transmitted to the AP. In this case, the STA1 may transmit a PS-poll frame in which the UDI 610 is set to 1 to the AP. STA2 to STA5 may receive the downlink data to be received from the AP on the basis of the TIM, and may transmit a PS-poll frame 620 to the AP.

The AP may receive the PS-poll frame 620 and the UDI 610 and schedule resources for downlink transmission of the AP and uplink transmission of the STA. The AP may transmit information on the scheduled resource through the resource allocation frame 640. The plurality of STAs receiving the resource allocation frame 640 may transmit an uplink frame or receive a downlink frame based on the resource allocation information included in the resource allocation frame 640.

RAW can be divided into RAW1 and RAW2. In RAW1, the PS-poll frame 620 and the UDI 610 may be transmitted by the STA. In RAW2, a resource allocation frame 640 may be transmitted, and an uplink frame or a downlink frame may be transmitted or received based on a resource allocated by the resource allocation frame 640.

The raw parameter set (RPS) element may include a parameter for a RAW-based channel access operation. The RPS may be included in the beacon frame or the probe response frame. For example, the RPS element may include a RAW slot, a RAW start time, information about a RAW group, and the like. The raw parameter set (RPS) element may be transmitted to the STA through a beacon frame.

FIG. 7 illustrates interworking between a wireless LAN system and a cellular network (eg, an LTE system, an LTE-A system-based network, etc.) system among heterogeneous network systems (or a plurality of radio access technology (RAT) systems). A wireless communication method of an STA is disclosed.

Referring to FIG. 7, an STA may have a capability of accessing all eNBs of an AP cellular network of a WLAN. The STA may request a connection to a specific network in order to access a specific network of a WLAN and a cellular network. Although STAs can access each of the heterogeneous networks, they cannot access both heterogeneous networks at the same time.

The eNB may be connected to a serving gateway (S-GW) / mobility management entity (MME) via a cellular network interface. The MME has access information of the terminal or information on the capability of the terminal, and this information may be mainly used for mobility management of the terminal. The MME is responsible for the function of the control plane. S-GW is a gateway having an E-UTRAN as an endpoint. S-GW is in charge of the user plane. The S-GW / MME is also connected to a PDN (packet data network) gateway (P-GW) and a home subscriber server (HSS) via a cellular network interface. The PDN-GW is a gateway having a packet data network (PDN) as an endpoint.

In addition, the P-GW and HSS are connected with a 3GPP access authentication authorization (AAA) server through a cellular network interface. The P-GW and 3GPP AAA servers may be connected with an evolved packet data gateway (e-PDG) via a cellular network interface. e-PDG may only be included in untrusted non-3GPP connections. A WLAN access gateway (WAG) may play a role of P-GW in a WLAN system.

The communication on the heterogeneous network through the conventional WLAN and the cellular network was performed based on the request of the STA. In the conventional case, rather than direct interworking between the WLAN and the cellular network, a specific network server manages the WLAN information and requests based interworking of the STA of a method of performing handover between the WLAN and the cellular network at the request of the STA. Working was performed.

In addition, radio level control was not performed in communication on a heterogeneous network of STAs, and only network level flow mobility / IP-flow mapping was supported.

That is, in a conventional heterogeneous network, a connection for transmitting and / or receiving direct control information between a WLAN and a cellular network is not required. However, in order to increase the efficiency of the STA performing communication based on the WLAN and the cellular network, the communication on the heterogeneous network based on the direct interworking between the WLAN and the cellular network, rather than the communication on the heterogeneous network based on the request of the STA. This is necessary. When direct transmission and reception of control information between the WLAN and the cellular network is performed, efficient and fast interworking between the WLAN and the cellular network may be performed.

In an existing WLAN environment, as the number of STAs increases, the resources used to access the STAs may also increase proportionally. In a channel access method based on a content free (POLL) -Poll frame, the AP accesses a CF-poll to all STAs included in a poll list in order to guarantee an opportunity for transmission of an uplink frame in a polling interval. You need to send a frame. However, some STAs receiving the CF-poll frame transmitted by the AP may not have data to be transmitted to the AP through uplink. In this case, waste of radio resources occurs. In particular, when the number of STAs is increased in a dense WLAN environment, waste of radio resources becomes greater, and as a result, many STAs may have difficulty in channel access.

In a dense WLAN environment, when the number of STAs increases, RAW-based channel access may have the following problems. In the conventional PS-Poll frame-based channel access method, resources for transmitting and receiving the frame of the above-described RAW-based STA may be allocated to the STA. If RAW is configured for both a paged STA and a nonpaged STA, if the nonpaged STA does not have uplink data to transmit, waste of resources may occur. If the RAW is configured only for the paged STA, the above waste of resources can be prevented. However, if the STA has uplink data to be transmitted, a delay of transmission for an uplink frame of the STA may occur.

In addition, in the existing WLAN environment, there is a lack of consideration for an STA that fails to transmit an uplink frame.

Hereinafter, in an embodiment of the present invention, a WLAN polling operation based on a cellular network for increasing a transmission success rate of an uplink frame of an STA is disclosed in consideration of a wireless communication environment. In a cellular network-based WLAN polling operation according to an embodiment of the present invention, the AP may schedule uplink transmission of an STA that fails to transmit an uplink frame based on the cellular network.

Hereinafter, an embodiment of the present invention will be described assuming that a heterogeneous network (or a plurality of RATs) is a WLAN and a cellular network. However, a procedure for uplink transmission of a terminal according to an embodiment of the present invention may also be performed between different heterogeneous networks.

Referring to FIG. 8, offloading of data may be performed through interworking between the WLAN and the cellular network, and the maximum throughput of the data may be increased.

A cellular network based WLAN polling operation according to an embodiment of the present invention may be performed based on a connection between a WLAN and a cellular network as described below.

A wireless control connection 800 may be performed between the eNB and the AP. In addition, a wired control connection 850 may be performed through S-GW, P-GW, and ePDG of the EPC. The wired control connection 850 may be performed based on a new interface over a backbone network based on GPRS tunneling protocol (GTP) or a new protocol. The radio control connection 800 may be a connection between the eNB and the AP. The AP may support not only an 802.11 MAC / PHY layer for the wireless control connection 800, but also an LTE protocol stack for communication with the eNB.

According to an embodiment of the present invention, interworking between a WLAN and a cellular network may be directly performed in a core network such as an evolved packet core (EPC). That is, control information between the WLAN and the cellular network can be directly transmitted and received within the core network.

When the STA supports both the WLAN and the cellular network, the STA has a wide coverage, the cellular network system transmitting control information may be a primary system, and the WLAN system performing data transmission with a narrow coverage may be a secondary system.

When a cellular network based WLAN polling operation according to an embodiment of the present invention is performed, an entity associated with the cellular network may be used for interworking between the cellular network and the WLAN. For example, existing entities such as eNB, MME, P-GW can be used for interworking between cellular network and WLAN. Alternatively, a new entity for interworking between a cellular network and a WLAN, such as an InterWorking Management Entity (IWME) (not shown), may be defined in the core network.

An interworking function may be implemented in entities for interworking between heterogeneous networks. The interworking function may define a procedure for interworking between heterogeneous networks at the wireless network level and the core network level. An entity for interworking between heterogeneous networks may store and manage information related to an AP.

Hereinafter, it is assumed that the STA is a dual mode STA capable of supporting a WLAN and a cellular network.

In FIG. 9, a method of controlling an AP of a WLAN and managing information about an AP in a cellular network is disclosed.

Referring to FIG. 9, an air interface between the eNB 900 and the AP 910 may be used for controlling the AP 910. The eNB 910 may control the AP 910 similarly to a general UE communicating with the eNB 900 based on a radio control connection between the AP 910.

Alternatively, the AP 910 may be controlled based on the backhaul interface between the eNB 900 and the AP 910. The eNB 900 may control the AP based on a wired control connection.

Alternatively, the AP 910 may be controlled based on a control interface between the MME 920 and the AP 910. The AP 910 may be controlled based on a control connection between the MME 920 and the AP 910 of the core network of the cellular network. Radio control connections between the eNB 900 and the AP 910 may also be used to control the AP based on the MME 920.

Alternatively, a control interface between the IWME 930 and the AP 910 may be used for the control of the AP 910.

According to an embodiment of the present invention, the STA 950 may poll an uplink frame based on a cellular network. Based on the transmission of the uplink frame based on the cellular network, the QoS of the STA 950 and the uplink access opportunity of the STA 950 may be improved and the utilization efficiency of radio resources may be improved.

For example, when the STA 950 has an uplink frame to be transmitted to the AP 910, the STA 950 may transmit a buffer status message including information about a state of the uplink frame buffered to the cellular network. The STA 950, which previously failed to transmit the uplink frame, may include additional information related to the transmission failure of the uplink frame in the buffer status message and transmit the same to the cellular network.

The entity of the cellular network (eg, the IWME 930) that has received the buffer status message may determine whether to perform cellular network based polling. When the cellular network based polling is performed, it is possible to guarantee the transmission opportunity of the STA 950 to transmit the uplink frame in the polling interval. In addition, the STA 950 that fails to transmit the uplink frame may be scheduled with a higher priority.

For example, when the AP 910 polls the STA 950 based on the CF-Poll frame, the AP 910 transmits an access category (AC), transmission of an uplink frame to be transmitted by the STA 950. In consideration of the transmission time of the failed uplink frame, the scheduling may be performed by increasing the priority of the specific STA 950.

As another example, when channel access is performed based on the PS-poll frame transmitted by the STA 950, the AP 910 adjusts a parameter related to RAW to increase the priority of a specific STA so as to increase the priority of the STA 950. Channel access can be scheduled.

Hereinafter, a WLAN polling procedure based on a cellular network according to an embodiment of the present invention will be described in detail.

In FIG. 10, the WLAN polling operation based on the cellular network may be performed based on an entity of a cellular network such as eNB / MME / IWME. Hereinafter, for convenience of description, it is assumed that the cellular network-based WLAN polling operation is performed based on the IWME.

Referring to FIG. 10, the AP may transmit a cellular coordinated polling message to the IWME (step S1000).

The cellular coordination poll request message may be a message for requesting support of cellular network based polling. Polling based on the cellular network may mean controlling channel access of the STA by the cellular network. The AP and the IWME may adjust whether to support cellular network based polling based on a cellular coordination polling request message / cellular coordination polling response message in advance.

The IWME may send a cellular coordinated polling response message to the AP (step S1010).

The IWME may send a cellular coordination poll response message to the AP in response to the cellular coordination poll request message sent by the AP. The cellular coordination poll response message may indicate support of cellular network based polling by the IWME.

When the cellular network based polling is determined to be supported by the IWME, the IWME may determine whether to perform the cellular network based polling based on the buffer status report message transmitted by the STA.

That is, a coordination process of whether to support a cellular network based polling operation between the AP and the IWME may be performed through steps S1000 and S1010. The IME may consider various factors to determine whether to support a polling operation.

For example, the IWME may determine whether to support a cellular network based polling operation in consideration of a delay for transmitting data (eg, control data) to the AP through the cellular network. In addition, the IWME may determine whether to support the cellular network based polling operation in consideration of various factors such as information on a channel between the AP and the STA.

The AP transmits a beacon frame or probe response frame to the STA (step S1020).

The AP may transmit a beacon frame or probe response frame including parameter information (CF parameter, RPS) for channel access to the STA.

The AP supporting the cellular network based polling may inform the STA that the cellular network based polling is supported to the STA through the beacon frame or the probe response frame. For example, a cellular coordinated polling indicator may be included in a CF Parameter Set element or an RPS element of a beacon frame or probe response frame and transmitted. For example, an AP supporting cellular network based polling may transmit a beacon frame or probe response frame in which the cellular coordination polling indicator is set to 1 to the STA. The cellular coordination poll indicator may be represented by polling indication information in other terms.

Hereinafter, when cellular network based polling is supported, the operation of the STA is initiated.

If there is a buffered uplink frame in the STA, the STA may transmit a buffer status report message (or uplink data indication message) to the IWME (step S1030).

The STA may send a buffer status report message to the IWME via the cellular network. Alternatively, the STA may indicate the existence of an uplink frame to the IWME through a UL UL data indicator message. Hereinafter, in the embodiment of the present invention, when there is an uplink frame buffered in the STA for convenience of description, a message transmitted by the STA is represented by a term of an uplink data indication message.

The uplink data indication message may include identifier information (eg, SSID and BSSID) of the AP connected to the STA, identifier information (eg, an association identifier (AID)) of the STA, service type or access category of the uplink frame. It may include at least one of information on whether or not the transmission of the uplink frame (or the number of times), the transmission failure time of the uplink frame, the size of the uplink frame, the channel status, the transmission time of the message.

According to another embodiment of the present invention, the STA may request a cellular network based polling to the IWME by transmitting an uplink data indication message only when a certain transmission condition is satisfied. For example, an STA may transmit an uplink data indication message for requesting a cellular network based polling to an IWME only for an STA that transmits an uplink frame to guarantee QoS or an STA that fails to transmit an uplink frame more than a predetermined number of times. .

Alternatively, the STA may transmit an uplink data indication message to the IWME when the measured channel quality between the AP and the STA deviates from a predetermined specific threshold. The measured channel quality between the AP and the STA may be measured based on, for example, an Average Noise Power Indicator (ANPI) or a Received Signal to Noise Indicator (RSNI).

The IWME may determine whether to perform cellular network based polling (step S1040).

The IWME may receive the uplink data indication message and determine whether to perform the cellular network based polling. For example, the IWME may determine whether to perform cellular network based polling in consideration of the channel state between the STA and the AP. In more detail, the IWME may determine whether to perform cellular network based polling in consideration of channel state information included in an uplink data indication message transmitted by the UE.

For example, the STA may measure channel quality between the AP and the STA, and the information about the measured channel quality may be transmitted to the IWME. The IWME may determine whether to perform cellular network based polling based on information on channel quality between the AP and the STA.

If the IWME determines to perform the cellular network based polling, the AP transmits STA polling information based on the uplink data indication message received from the STA to the AP (step S1050).

The IWME may deliver polling information determined based on an uplink frame indication message received from the STA to the AP. The AP receiving the polling information may be indicated based on the uplink data indication message.

When the IWME transfers the uplink frame indication message received to the AP as it is, polling information may be in the format of an uplink data indication message received from the STA. Alternatively, the polling information may include only some information of the information included in the uplink data indication message or may be an uplink data indication message in a format changed so that the AP can receive it.

In addition, when the IWME determines to perform the cellular network based polling, a response message to the uplink data indication message received from the STA is transmitted to the STA (step S1060).

The IWME may transmit a response message to the STA, such as an uplink frame indication message, to the STA.

According to an embodiment of the present invention, the AP may re-determine whether to perform a cellular network based polling operation based on the information on the transmission time of the uplink data indication message included in the polling information received through the IME. For example, the AP may establish a cellular network (IWME) from the STA based on the information on the transmission time of the uplink data indication message and the reception time of the uplink data indication message based polling information transmitted to the AP through the STA and the IWME. The uplink data indication message transmitted through the AP may be transmitted to the AP.

If the propagation time is greater than or equal to the size of the predefined time, the AP may stop the cellular network based polling operation. The AP may instruct the STA to stop the cellular network based polling operation through the aforementioned cellular based polling indicator included in the beacon frame or the probe response frame.

When the cellular network based polling operation is stopped, the AP may perform the polling operation by itself. For example, the AP may transmit a frame for polling to all STAs included in a poll list in a content period (CP) based on a parameter set by itself.

The AP may adjust a parameter for channel access of the STA based on polling information received from the IME (step S1070).

For example, the AP may update information for channel access such as a CF parameter element and an RPS element for the STA so that uplink transmission by the STA has priority. The AP may transmit the updated CF parameter element and the RPS element to the STA through the beacon frame or the probe response frame.

As a specific example, the AP may adjust the RPS element for the failed transmission STA for preferential scheduling for the RAW group including the uplink transmission failed STA. The AP may adjust the N offset for slot allocation or slot duration for priority scheduling for a specific STA (or a RAW group including the specific STA) that has transmitted the uplink data indication message.

The AP may allocate uplink resources based on polling information received from the IME (step S1080).

The AP may allocate an uplink resource for transmitting uplink data of a specific STA that has transmitted an uplink frame indication message. For example, the AP may transmit a resource allocation frame including resource allocation information for the specific STA that has transmitted the uplink frame indication message to the STA.

The STA transmits an uplink frame (step S1090).

The STA may transmit an uplink frame through an uplink resource allocated by a resource allocation frame determined through cellular network based polling.

The AP supporting the cellular network based polling operation may not poll all STAs included in the polling list in the CP period. For example, the AP may not perform polling for the STA that has no downlink data to receive and transmits a buffer status message to the IWME. In addition, some of the STAs that want to transmit the uplink frame may not transmit the UDI indicating the existence of the uplink frame buffered in the RAW to the AP. For example, an STA that transmits an uplink frame indication message receives uplink transmission by receiving a resource allocation frame transmitted from an AP through cellular network based polling without transmitting a UDI indicating whether to transmit an uplink frame. Obtain resources for

Referring to FIG. 11, the wireless device 1500 may be an STA that may implement the above-described embodiments and may be an AP 1100 or a non-AP STA (or STA) 1150.

The AP 1100 includes a processor 1110, a memory 1120, and an RF unit 1130.

The RF unit 1130 may be connected to the processor 1120 to transmit / receive a radio signal.

The processor 1120 may implement the functions, processes, and / or methods proposed in the present invention. For example, the processor 1120 may be implemented to perform the operation of the wireless device according to the above-described embodiment of the present invention. The processor may perform an operation of the wireless device disclosed in the embodiment of FIGS. 6 to 10.

For example, the processor 1120 may be implemented to send a cellular coordination poll request message to the IWME and to receive a cellular coordination poll response message from the IWME.

The STA 1150 includes a processor 1160, a memory 1170, and a radio frequency unit 1180.

The RF unit 1180 may be connected to the processor 1160 to transmit / receive a radio signal.

The processor 1160 may implement the functions, processes, and / or methods proposed in the present invention. For example, the processor 1120 may be implemented to perform the operation of the wireless device according to the above-described embodiment of the present invention. The processor may perform the operation of the wireless device in the embodiment of FIGS. 6 to 10.

For example, the processor 1160 may be implemented to receive a first scanning frame from an AP and transmit an uplink data indication message to a cellular network entity via the cellular network based on polling indication information of the first scanning frame. . In addition, the processor 1160 may be implemented to receive a second scanning frame from the AP and transmit an uplink frame based on the adjusted channel access parameter included in the second scanning frame. The polling indication information includes information indicating support of cellular network based polling, the uplink data indication message includes information on an uplink frame, and the adjusted channel access parameter is uplink data received from the cellular network entity. It may be determined by the AP based on the indication message.

The

processors

1110 and 1160 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters for interconverting baseband signals and wireless signals. The

memories

1120 and 1170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The

RF unit

1130 and 1180 may include one or more antennas for transmitting and / or receiving a radio signal.

When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the

memories

1120 and 1170 and executed by the

processors

1110 and 1160. The

memories

1120 and 1170 may be inside or outside the

processors

1110 and 1160 and may be connected to the

processors

1110 and 1160 by various well-known means.

Claims

In the uplink transmission method of the STA (station),
STA receiving a first scanning frame from an access point (AP)
Transmitting, by the STA, an uplink data indication message to a cellular network entity through a cellular network based on polling indication information of the first scanning frame;
The STA receiving a second scanning frame from the AP; And
Transmitting, by the STA, an uplink frame based on the adjusted channel access parameter included in the second scanning frame;
The polling indication information includes information indicating support of the cellular network based polling,
The uplink data indication message includes information on the uplink frame.
The adjusted channel access parameter is determined by the AP based on the uplink data indication message received from the cellular network entity.
The method of claim 1,
The uplink data indication message is transmitted only when the uplink frame is a retransmission frame.
The information on the uplink frame includes information on the number of transmission failures of the uplink frame and information on the transmission failure time of the uplink frame.
The method of claim 1,
The STA further includes receiving a resource allocation frame from the AP,
The resource allocation frame includes information on the resource for transmission of the uplink frame determined based on the uplink data indication message,
The adjusted channel access parameter comprises a raw parameter set (RPS) element for preferential scheduling for a restricted access window (RAW) group in which the STA is included.
The method of claim 1,
The uplink data indication message further includes information on a channel state between the AP and the STA.
And wherein the cellular network entity determines whether to forward the uplink data indication message to the AP based on the information on the channel state.
In a station for performing uplink transmission, the STA includes:
RF (radio frequency) unit for transmitting or receiving a radio signal; And
Including a processor that is operatively connected to the RF unit,
The processor receives a first scanning frame from an access point (AP),
Transmit an uplink data indication message to a cellular network entity through a cellular network based on the polling indication information of the first scanning frame,
Receiving a second scanning frame from the AP,
The uplink frame is transmitted based on the adjusted channel access parameter included in the second scanning frame.
The polling indication information includes information indicating support of the cellular network based polling,
The uplink data indication message includes information on the uplink frame.
The adjusted channel access parameter is determined by the AP based on the uplink data indication message received from the cellular network entity.
The method of claim 5,
The uplink data indication message is transmitted only when the uplink frame is a retransmission frame.
The information on the uplink frame includes information on the number of transmission failure times of the uplink frame and information on the transmission failure time of the uplink frame.
The method of claim 1,
The processor is implemented to receive a resource allocation frame from the AP,
The resource allocation frame includes information on the resource for transmission of the uplink frame determined based on the uplink data indication message,
The adjusted channel access parameter includes a raw parameter set (RPS) element for preferential scheduling for a restricted access window (RAW) group in which the STA is included.
The method of claim 5,
The uplink data indication message further includes information on a channel state between the AP and the STA.
Wherein the cellular network entity determines whether to transmit the uplink data indication message to the AP based on the information on the channel state.