WO2016114425A1

WO2016114425A1 - Method for retransmitting data in network linking plurality of communication systems and apparatus for same

Info

Publication number: WO2016114425A1
Application number: PCT/KR2015/000376
Authority: WO
Inventors: 최혜영; 조희정; 고현수; 변일무; 박경민
Original assignee: 엘지전자 주식회사
Priority date: 2015-01-14
Filing date: 2015-01-14
Publication date: 2016-07-21

Abstract

A method for retransmitting data from a base station of a first communication system in a network in which a plurality of communication systems are linked, according to the present invention, may comprise the steps of: transmitting, to a base station of a second communication system, information related to downlink data to be transmitted using a radio access level-split bearer to transreceive data between the base station of the first communication system and the base station of the second communication system; receiving, from the base station of the second communication system, a confirmation response to an indication, when the information related to the downlink data to be transmitted using the radio access level-split bearer indicates carrying out retransmission from the base station of the first communication system; transmitting the downlink data to the base station of the second communication system based on the confirmation response; and retransmitting the downlink data to a terminal when a specific condition is satisfied.

Description

【Specification】

[Name of invention]

Method and apparatus for retransmitting data in a network interworking with a plurality of communication systems

Technical Field

The present invention relates to wireless communication, and more particularly, to a method and apparatus for retransmitting data in a network interworking with a plurality of communication systems.

Background Art

[002] There may be a Mult i-RAT terminal having a capability of accessing two or more radio access technologies (RAT) or black communication systems in a wireless communication system. In order to access a specific RAT, a connection ion is set to a specific RAT based on a terminal request and data transmission and reception are performed. However, even if the Mult i-RAT terminal is able to access more than one RAT, it was not possible to simultaneously access the mult iple RAT. That is, even if there is a Mult i-RAT capabi l i ty, the current UE cannot simultaneously transmit and receive data through different RATs.

Since the conventional mult i-RAT technology does not require interworking between the WLAN and the saller network, overall system efficiency is low. In addition, even if the terminal can simultaneously access the Mult iple RAT, it was possible to simultaneously access the Mult iple RAT by supporting only the f low mobility / IP-f low mapping at the network level without control at the radio level. For this reason, the prior art does not require any control connection between the AP and the cellular network, and has been progressed based on the request of the terminal. ^'

However, such a conventional technology does not grasp the exact situation of the network, there is a limit to increase the overall network efficiency by selecting the terminal-oriented RAT. In particular, as a terminal becomes accessible to a plurality of communication systems,

In the case of Cel lular / Wi-Fi Radio level converged networks, the retransmission procedure method has not been suggested due to the data transmission failure in the WLAN. It was difficult to carry out.

[Detailed Description of the Invention]

[Technical problem]

The technical problem to be achieved in the present invention is to provide a method for retransmitting data by the base station of the first communication system in a network interworking with a plurality of communication systems.

Another object of the present invention is to provide a base station of a first communication system for retransmitting data in a network interworking with a plurality of communication systems.

Technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems not mentioned may be clearly understood by those skilled in the art from the following description. There will be.

Technical Solution

The method for retransmitting data by the base station of the first communication system in a network interworking with a plurality of communication systems for achieving the above technical problem, the data between the base station of the first communication system and the base station of the second communication system Transmitting information related to retransmission of downlink data to be transmitted by using a bearer branched to a radio level for transmission and reception to a base station of the second communication system; When the information related to the retransmission of the downlink data to be transmitted using the bearer branched to the radio level indicates that the base station of the first communication system performs retransmission, an acknowledgment answer for the indication is sent to the second communication system. Receiving from a base station; Transmitting downlink data to a base station of the second communication system based on the confirmation answer; And retransmitting the downlink data to the terminal if a predetermined condition is satisfied. Information related to retransmission of downlink data to be transmitted by using a bearer branched to the radio level is based on a condition for performing retransmission in the first communication system or a radio link control (RLC) of a base station of the first communication system of the downlink data. Or LI fetime information in a medium access control (MAC) layer. The first communication The condition to perform the retransmission in the system may include the number of retransmission of the downlink data of the base station of the second communication system. .

When the predetermined condition is satisfied, it may include receiving a message for requesting retransmission of the downlink data from a base station of the second communication system. Alternatively, the case where the predetermined condition is satisfied may include a case in which an ACK signal for the downlink data is not received until the timer started while transmitting the downlink data to the second communication system expires. . The message may include a sequence number of the downlink data. The message may be received from the base station of the second communication system when the second communication system retransmits the downlink data a predetermined number of times but the terminal does not receive it successfully. The first communication system is a seller communication system and the second communication system is a wireless local area network (WLAN) communication system.

In order to achieve the above technical problem, a base station of a first communication system for retransmitting data in a network interworking with a plurality of communication systems includes data between a base station of the first communication system and a base station of a second communication system. A transmitter configured to transmit information related to retransmission of downlink data to be transmitted using a bearer branched to a radio level for transmission and reception to a base station of the second communication system; When the information related to the retransmission of the downlink data to be transmitted using the bearer branched to the radio level indicates that the base station of the first communication system performs the retransmission, the acknowledgment of the indication is sent to the second communication system. A receiver configured to receive from a base station; The transmitter may be configured to transmit downlink data to a base station of the second communication system based on the acknowledgment answer, and include a processor for controlling the transmitter to retransmit the downlink data to a terminal when a predetermined condition is satisfied. Can be. If the predetermined condition is satisfied, it may include receiving a message for requesting retransmission of the downlink data from a base station of the second communication system. If the predetermined condition is satisfied, the downlink until the timer started while transmitting the downlink data to the second communication system expires. It may include a case in which an ACK signal for data is not received. The message may include a sequence number of the downlink data. The first communication system is a seller communication system and the second communication system is a WLAN communication system. The message may include a sequence number of the downlink data.

Advantageous Effects

According to the fast retransmission procedure proposed by the present invention when a delay occurs or data transmission fails when specific data branched from the cell-WLAN radio level converged network to the WLAN is transmitted through the WLAN, This allows faster retransmissions to improve communication performance.

The effects that can be obtained in the present invention are not limited to the above-mentioned effects, and other effects that are not mentioned above are clearly understood by those skilled in the art from the following description. Could be.

[Brief Description of Drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings included as part of the detailed description to provide a better understanding of the present invention provide embodiments of the present invention, and together with the detailed description, describe the technical idea of the present invention.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100.

FIG. 2 is a diagram illustrating a network structure of an Evolved Universal Mobile Telecom Systems (E-UMTS).

FIG. 3 is a diagram illustrating a network structure for explaining an interworking structure between a first communication system (eg, a cellar communication system) and a second communication system (eg, a wireless LAN communication system).

[017] FIG. 4 is an exemplary diagram for explaining a concept of security in a LTE / LTE-A system.

[018] FIG. 5 is a diagram illustrating Reassociat ion Procedures in an IEEE 802.11 WLAN system.

6 is a diagram illustrating examples of a structure of a WiFi-Cel lular converged communication system. FIG. 7 is a diagram illustrating examples without bearer splitting as radio level integrat ion-radio protocol architectures.

FIG. 8 is a diagram illustrating examples of bearer split as radio level integrat ion-radio protocol architectures.

9 is a diagram illustrating an example of a retransmission procedure according to the present invention.

FIG. 10 is a diagram illustrating a procedure in the case where the AP determines a reseller transmission.

FIG. 11 is a diagram illustrating a procedure when an eNB of a celler network determines retransmission.

12 shows fast salar data in salar-WLAN converged networks. Illustrates a procedure for the transmission.

FIG. 13 is a procedure for fast cellular data transmission in a celller-WLAN converged network according to FIG. 12 and is a procedure for an AP transmitting data within a specific time.

[027] FIG. 14 is a procedure for fast cellular data transmission in the celller-WLAN converged network according to FIG. 12, when the AP fails to transmit data within a specific time.

FIG. 15 is an exemplary diagram for describing a method of adjusting a data transmission rate in a cellular-WLAN converged network.

[Best form for implementation of the invention]

Hereinafter, preferred 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. For example, the following detailed description will be described in detail on the assumption that the mobile communication system is a 3GPP LTE, LTE-A system, except for the specific matters of 3GPP LTE, LTE-A. Applicable to any other mobile communication system.

In some cases, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices 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.

In addition, in the following description, it is assumed that a terminal collectively refers to a mobile or fixed user terminal device such as UE Jser Equipment (MSJ), MSCMobi le Stat ion (AMS), AMS (Advanced Mobi le Stat ion), or STA. In addition, it is assumed that the base station collectively refers to any node of the network terminal that communicates with the terminal such as Node B, eNode B, Base Stat ion, and Access Point (AP). Although described herein based on the IEEE 802.16 system, the contents of the present invention can be applied to various other communication systems.

In a mobile communication system, a user equipment (UE) may receive information from a base station through downlink ink, and the terminal may also transmit information through uplink ink. The information transmitted or received by the terminal includes data and various control information, and various physical channels exist according to the type and purpose of the information transmitted or received by the terminal.

[033] The following techniques are code division mult iple access (CDMA), frequency division mult iple access (FDMA), time division mult iple access (TDMA), orthogonal frequency division mul t iple access (0FDMA), SC-FDMA It can be used in various wireless access systems such as single carrier frequency division mult iple access. CDMA may be implemented by radio technology such as UTRACUniversal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented with wireless technologies such as Global System for Mobility Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolut ion (EDGE). 0FDMA may be implemented with a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRAC Evolved UTRA (etc.). UTRA is part of the UMTSOJniversal Mobile Telecommuni- cation Systems. 3GPP (3rd Generat ion Partnership Project) LTEdong term evolut ion is part of Evolved UMTS (E-UMTS) using E—UTRA and employs 0FDMA in downlink and SC-FDMA in uplink. LTE A (Advanced) is an evolution of 3GPP LTE.

In addition, 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. .

Although one base station 105 and one terminal 110 (including a D2D terminal) are shown to simplify the wireless communication system 100, the wireless communication system 100 may include one or more base stations and / Or it may include one or more terminals.

Referring to FIG. 1, the base station 105 includes a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit / receive antenna 130, a processor 180, and a memory 185. And a receiver 190, a symbol demodulator 195, and a receive data processor 197. The terminal 110 includes a transmit (Tx) data processor 165, a symbol tuner 175, a transmitter 175, a transmit / receive antenna 135, a processor 155, a memory 160, a receiver 140, A symbol demodulator 145 and a receive data processor 150 may be included. Although the transmit and receive antennas 130 and 135 are shown as one at the base station 105 and the terminal 110, respectively, the base station 105 and the terminal 110 are provided with a plurality of transmit and receive antennas. Accordingly, the base station 105 and the terminal 110 according to the present invention support a multiple iple input multiple output (MIMO) system. In addition, the base station 105 according to the present invention may support both a single user MIMO (MU-MUMO) MU ~ MUL (Mult i User-MIMO) scheme.

On the downlink, the transmit data processor 115 receives the traffic data, formats the received traffic data, codes it, interleaves and modulates (or symbol maps) the coded traffic data, and modulates symbols ( "Data symbols"). The symbol modulator 120 receives and processes these data symbols and pilot symbols to provide a stream of symbols.

The symbol modulator 120 multiplexes the data and pilot symbols and sends it to the transmitter 125. In this case, each transmission symbol may be a data symbol, a pilot symbol, or a signal value of zero. In each symbol period, pilot symbols may be sent continuously. Pilot symbols are frequency division multiplexed (FDM), orthogonal frequency division It may be a multiplexing (OFDM), time division multiplexing (TDM), or code division multiplexing (CDM) symbol.

[040] Transmitter 125 receives the stream of symbols and converts it into one or more analog signals and further adjusts (eg, amplifies, filters, and frequency upconverts) these analog signals. As a result, a downlink signal suitable for transmission over a wireless channel is generated, and then the transmitting antenna 130 transmits the generated downlink signal to the terminal.

In the configuration of the terminal 110, the receiving antenna 135 receives the downlink signal from the base station and provides the received signal to the receiver 140. Receiver 140 adjusts the received signal (eg, filters, amplifies, and frequency downconverts), and digitizes the adjusted signal to obtain samples. Symbol demodulator 145 receives received pilot symbols. Demodulate the signals to provide them to the processor 155 for channel estimation.

[042] The symbol demodulator 145 also receives a frequency equality estimate for the downlink from the processor 155, and performs data demodulation on the received data symbols to obtain data (which are estimates of the transmitted data symbols). Obtain symbol estimates and provide data symbol estimates to receive (Rx) data processor 150. Receive data processor 150 demodulates (ie, symbol demaps), deinterleaves, and decodes the data symbol estimates to recover the transmitted traffic data.

The processing by the symbol demodulator 145 and the receiving data processor 150 are complementary to the processing by the symbol modulator 120 and the transmitting data processor 115 at the base station 105, respectively.

The terminal 110 is on the uplink, the transmit data processor 165 processes the traffic data to provide data symbols. The symbol modulator 170 may receive and multiplex data symbols, perform modulation, and provide a stream of symbols to the transmitter 175. Transmitter 175 receives and processes the stream of symbols to generate an uplink signal. The transmit antenna 135 transmits the generated uplink signal to the base station 105.

In the base station 105, the uplink signal from the terminal 110 to the receiving antenna 130 Received through the receiver, the receiver 190 processes the received uplink signal to obtain samples. The symbol demodulator 195 then processes these samples to provide received pilot symbols and data symbol estimates for the uplink. The received data processor 197 processes the data symbol estimates to recover the traffic data sent from the terminal 110.

Processors 155 and 180 of each of terminal 110 and base station 105 instruct (eg, control, coordinate, manage, etc.) operation at terminal 110 and base station 105, respectively. Respective processors 155 and 180 may be connected with memory units 160 and 185 that store program codes and data. Memory 160, 185 is coupled to processor 180 to store operating systems, applications, and general files.

To [047] processor (155, 180) is a multiple _controller, (control ler), multiple micro-controller (microcontrol ler), a microprocessor (microprocessor), a microcomputer (microcomputer) or the like can also be referred to. Meanwhile, the processors 155 and 180 may be implemented by hardware or firmware (fir 'are), software, or a combination thereof. When implementing embodiments of the present invention using hardware, applicat ion speci fic integrated circuits (ASICs) or digital signal processors (DSPs), DSPDs (digital signal processing devices), PLDs ( Programmable logic devices (FIL), gate programmable gate arrays (FPGAs), and the like may be included in the processors 155 and 180.

Meanwhile, when implementing embodiments of the present invention using firmware or software, firmware or software may be configured to include modules, procedures, or functions for performing the functions or operations of the present invention. Firmware or software configured to perform the above may be provided in the processors 155 and 180 or stored in the memory 160 and 185 to be driven by the processor 155 and 180.

The layers of the air interface protocol between the terminal and the base station in the radio communication system (network) are based on the lower three layers of the OSKopen system interconnect ion model, which are well known in the communication system. L2, and the third layer L3. The physical layer belongs to the first layer and provides an information transmission service through a physical channel. RRC (Radio Resource Control) layer belongs to the third layer and provides control radio resources between the UE and the network. The terminal and the base station may exchange RRC messages through the wireless communication network and the RRC layer.

In the present specification, the processor 155 of the terminal and the processor 180 of the base station process signals and data except for a function of receiving or transmitting a signal and a storing function of the terminal 110 and the base station 105, respectively. For the convenience of description, the processor 155 and 180 will not be specifically described below. Although not specifically mentioned by the processors 155 and 180, it may be said that a series of operations of the data processing round are performed instead of the function of receiving or transmitting a signal and a storage function.

2 is a diagram illustrating a network structure of an Evolved Universal Mobile Telecom Systems (E-UMTS).

[052] The E-UMTS may be called like an LTE system. The system may be widely deployed to provide various communication services, such as voice ALV packet data, and is generally configured to function based on various techniques to be described and described in detail with reference to the following figures. 2, the E-UMTS network includes an Evolved UMTS terrestrial radio access network (E-UTRAN), an Evolved Packet Core (EPC), and one or more terminals. The E-UTRAN includes one or more base stations. In relation to EPC, the E / SAE gateway provides the endpoint's endpoint and mobility management functionality for the terminal. The base station and the MME / SAE gateway may be connected via the S1 interface. A base station is generally a fixed station that communicates with the terminal. In addition to being called a base stat ion, a base station may also be called an access point (AP). The base station provides end points of a user plane and a control plane to the terminal.

[053] A plurality of terminals may be located in one cell. One base station is generally arranged per cell. An interface for transmitting user traffic or control traffic may be used between the base stations. In this specification, "downl ink" refers to communication from a base station to a terminal, and "upl ink" refers to communication from a terminal to a base station. The MME / SAE gateway provides ciphering and integrity of distribution of paging messages to base stations, security control of idle ion mobility control, SAR bearer control and non-access stratum (NAS) signaling. It provides various functions including protect ion. The SAE gateway provides several functions including the termination of U-plan packets for paging reasons, the switching of the U-plan to support terminal mobility. For convenience of description, the MME / SAE gateway 30 may be referred to herein simply as a "gateway." However, it can be understood that this structure may include both the E gateway and the SAE gateway.

[055] A plurality of nodes may be connected between the base station and the gateway through the S1 interface. Base stations may be connected to each other via an X2 interface, and neighboring base stations may have a meshed network structure ¾ with an X2 interface.

[056] A network structure in which a plurality of communication systems using different wireless communication schemes interoperate with each other will be described.

FIG. 3 is a diagram illustrating a network structure for explaining an interworking structure between a first communication system (eg, a seller communication system) and a second communication system (eg, a wireless LAN communication system).

In the present invention, an LTE / LTE-A system as an example of the first communication system and a WiFi system as an example of the second communication system will be described.

In the network structure shown in FIG. 3, a backhaul control connect ion is established between the AP and the eNB through a backbone network (for example, P-GW or EPC (Evoed Packet Core)). Or, there may be a wireless control connect ion between the AP and the eNB. For peak throughput and data traffic off-loading, the UE uses a first wireless communication scheme (eg, LTE / LTE-A) through interworking between a plurality of communication networks. ) Can simultaneously support both a first communication system (or a first communication network) and a second communication system (eg, WiFi) using a second wireless communication scheme (eg, WiFi). Herein, the first communication network or the first communication system is referred to as a primary network or a primary system, respectively, and the second communication network or the second communication One system may be referred to as a secondary network or a secondary system, respectively. For example, the UE may be configured to simultaneously support LTE / LTE-A and WiFi (local area communication system such as WLAN / 802. 11). Such a UE may be referred to herein as a multi-system support UE (MUL).

In the network structure shown in FIG. 3, the primary system has wider coverage and may be a network for transmission of control information. An example of a primary system may be an LTE / LTE-A system. Meanwhile, the secondary system is a network having a small coverage and may be a system for data transmission. The secondary network may be, for example, a WLAN system such as WLAN or WiFi. The AP, which is the access point of the secondary system (e.g., WiFi), and the base station (eNB), which is the access point of the primary system (e.g., cellular communication system, such as LTE / LTE-A system), Assume that a connection (connect i on) is established. In the present invention, the AP having a radio interface with the eNB should support not only 802.11 MAC / PHY, but also LTE protocol stack or WiMAX protocol stack for communication with the eNB, and serves as a terminal with the _e NB and communicates with the eNB. can do.

FIG. 4 is an exemplary diagram for explaining a concept of security in an LTE / LTE-A system.

[062] LTE certification

When the UE (UE) requests access to the LTE network, mutual authentication between the user and the network is performed using the AKA procedure. The HSS sends an authentication vector composed of {RAND, XRES, AUTH _HSS , K _ASME } to the MME, and the MME performs mutual authentication with the UE. The MME stores the authentication vector and sends the RAND and AUTN _HSS values to the UE. The UE generates the RES, AUTNUE, and K _ASME using the AKA algorithm, and then sends the RES values to the E. . The UE authenticates the network by comparing the AUTNUE value generated by the UE with the AUTNRSS value received from the E, and the MME authenticates the user by comparing the XRES received from the HSS with the RES received from the UE. After mutual authentication, the UE and the MME share the KASME. Security relations between two UEs are defined between UE (UE) and E-UTRAN or CN (Core Network), and the first layer is described as AS (Access Stratum), which is used for RRC signaling between user and base station. Protect UP (User Plane) data. The second layer is described as non-access stratum (NAS), which protects CP (Control Plane) signaling between the user and the MME.

[065] NAS Securi ty

After mutual authentication and sharing the K _ASME , the UE and the MME perform a NAS Securi ty Setup procedure for generating a NAS security key. The NAS Security Set up is performed through a Security Mode Command I Security Mode Complete message, which is a NAS signaling message, and is initiated by the MME sending a Security Mode Co 圆 and message to the UE.

First, the MME selects the NAS Securi ty algorithm and then obtains the integrity key ^^ and the encryption key K _NASenc from K _ASME . Thereafter, a Security Mode Command message including a NAS message authentication code (NAS-MAC) generated using the selected integrity and encryption algorithm and K _NAS i _nt is transmitted to the UE.

After receiving the Securi ty Mode Co. and message, the UE checks the integrity of the received message using a NAS Security algorithm selected by the MME and generates NAS Securi ty keys (^ and K _NASenc ). Afterwards, NAS Security Setup is completed by sending the message Securi ty Command Complete to E. The Security Mode Complete message is encrypted using 1½ and transmitted with the message authentication code NAS-MAC generated with ^^. After completing NAS Security Setup, NAS signaling messages between UE and E are transmitted with integrity check and encryption.

[069] AS Security

[070] The UE (UE) and MME that have completed mutual authentication calculate K _eNB from K _ASME and 廳 E transmits it to eNB so that UE (UE) and eNB perform AS Security Setup procedure for AS Securi key generation. Perform. AS Securi ty Setup is done through Security Mode Command I Securi ty Mode Complete message, which is an RRC signaling message. The eNB starts by sending a Security Mode Co 謹 and message to the UE.

First, the eNB obtains an integrity key 1½ (; ^ and an encryption key 1½ (:) to use for the RRC signaling message from the AS Security algorithm, and then obtains the encryption key K _UPenc to be used in the user plane. And a Security Mode Command message including a Message Authentication Code for Integrity (MAC-I) generated using the IR _C i _nt to the UE.

After receiving the Security Mode Command message from the eNB, the UE checks the integrity of the received message using the AS Security algorithm selected by the eNB and generates AS Security keys (KRR _Cint , l _menc , jp _enc ). do. After that, the AS Security Setup is completed by sending a Security Command Complete message to the eNB. This Security Mode Complete message is sent with the message authentication code MAC-I created using KRR _C _nt . After completing the AS Security Setup, the RRC signaling message between the UE and the eNB performs integrity check and encryption, and user plane data is transmitted with encryption.

In the following description, connection ion procedures of the IEEE 802.11 WLAN system will be described.

In the connection procedure, the scanning step is divided into passive scanning and active scanning, and the terminal (for example, the STA) searches for the neighbor AP in the scanning step to store information, receives a beacon frame of the neighbor AP, and Send and receive probes and probe response frames. Next, as a join step, the UE selects and synchronizes an AP among the discovered neighbor APs and collects information on the AP. Then, a beacon frame of the selected AP is received. Next, as an authentication step, the terminal is authenticated. In the open system authentication procedure, the AP performs authentication unconditionally upon the authentication request of the terminal, and the Shared Key authentication procedure performs authentication by confirming the shared secret key. Send and receive an authentication frame. Next, in the Association step, the terminal is assigned an Association IDGdentif ier) through the Association Response frame, and transmits and receives an Association Request and Response frame.

5 illustrates reassociation procedures in an IEEE 802.11 WLAN system. Illustrated drawing.

Reassociation occurs when a terminal (STA) moves to another AP coverage. A terminal (STA) transmits information on a medium access control (MAC) address of a current AP to a new AP through a reassociation request frame. Thereafter, IAPP (Inter-AP Protocol) messages are exchanged between the New AP and the Old AP. The new AP requests the IAPP to relay the information of the old AP, and the old AP deletes the AIDCAssociation Id) of the terminal. IAPP (Inter-AP Protocol) 802.11f is a protocol for exchanging context between APs through a DS in a wireless local area network (WLAN) system, which caches the PMK information exchanged by the AP and the terminal's key used by the old AP. When requesting reassociation using identifier (keylD), AP skips authentication process using cached PMK and performs key exchange.

[077] Disassociation Procedures of IEEE 802.11 WLAN will be briefly described. Disassociation is a notification, not a request. The AP needs to disassociate the terminals (STAs) to enable the AP to be removed from the network for service or for other reasons. When the STAs leave the network, the STAs attempt to disassociate. Transmit a disassociation frame, which contains a reason code.

Scanning / join related frames in the IEEE 802.11 WLAN system will be described.

Beacon frame (Beacon frame): Although transmitted periodically only in the AP, if the channel is busy at the time to be transmitted, transmission may be delayed. The frame control includes Duration, DA, SA, BSSID, Fragment number, Sequence information, and the frame body includes Time stamp, beacon interval, capability information, {SSID, Supported rates, DS parameter Set, TIM} IEs. TIM is used as an indication (AID indication) to wake up a UE in Traffic Indication MAP, Doze mode.

Probe request frame: used in active scanning. Frame contn) l includes Duration = 0x0000, DA = broadcast, SA, BSSID = any AP, Fragment number and Sequence. The frame body contains {SSID, Supported Rates} IEs. [081] Probe response frame: It is sent with a male answer to the probe. Frame control includes Duration, DA, SA, BSSID, fragment number, Sequence, and frame body includes Time stamp, beacon interval, capability information, {SSID, supported rate, DS parameter Set} IEs.

[082] Association related frames in the IEEE 802.11 WLA system will be described.

[083] Authentication frame (Authentication frame): Used for authentication request and ques- tion, it is divided into Authentication transaction Sequence because the format is same. Frame contr contains Duration, DA, SA, BSSID, Fragment number, Sequence, and Frame body contains Authentication Algorithm Number, Status code, Challenge text IE. Authentication Algorithm Number ： Open System, Shared Key, Fast BSS Transition

Association request frame: Contains a listen interval that specifies how long to stay in the association request 入 1 power saving mode. Frame contr contains Duration, DA, SA, BSSID, Fragment number, Sequence, and Frame body contains Capability information, Listen Interval, {SSID, Supported Rates} IEs.

Association response frame: A response to the Associa ion request is transmitted and assigned an AID value. Frame control includes Duration, DA, SA, BSSID, fragment number, Sequence, and frame body contains Capability information, Status Code, Association ID, Supported rates IE.

Re / Disassociation related frames in IEEE 802.11 WLAN will be described.

Reassociation request frame: Includes a listen interval that specifies how long to stay in power saving mode when requesting reassociation. Frame control includes Duration, DA, SA, BSSID, Fragment number, Sequence, and frame body contains Capability information, Listen Interval, Current AP address, {SSID, Supported Rates} IEs.

Reassociation response frame: The same frame as the Association response frame is used and an AID value to be used in the new AP is allocated. Frame contr includes Duration, DA, SA, BSSID, fragment number, Sequence, Frame body is Capability Informat ion, Status Code, Associat ion ID, and Supported rates IE.

Frame contr in the disassociat ion / Deauthent icat ion frame includes Durat ion, DA, SA, SSID IE, fragment number, Sequence, and frame body contains Reason Code.

The above description of the IEEE 802.11 WLAN can be applied in the context of the present invention. Conventional inter RAT technology is designed based on the request of the terminal, does not require interworking between the WLAN and the cellular network, the specific network server manages the WLAN information, and inter- Enable RAT handover. In addition, even if the UE can simultaneously access the Mult iple RAT, it is possible to simultaneously access the Mult iple RAT by supporting only f low mobi 1ity / IP-f low mapping at the control network level at the radio level. It was. For this reason, the prior art did not require any control connection between the AP and the salar network, and allowed to connect to Mul t iple RAT based on the request of the terminal. Such a prior art does not accurately grasp the situation of the network, there is a limit to increase the overall network efficiency by the terminal-oriented RAT selection.

In order to improve not only the QoS of the UE through the use of Mult i-RAT, but also the overall network efficiency, it is necessary to provide a network-based tightly-coupled mult i-RAT management technology rather than the UE request. Network levels require more efficient and faster inter-RAT interworking by establishing direct control connections between different RATs. The advantages of the radio level convergence network are 1) enabling unified contr and management of the mult i-RAT of the operator, and 2) radio resource management according to real-time channel and load conditions. Improve capacity and QoE, and 3) use reliable cell network as contn) and mobi li anchor to improve QoE, minimize service interrupt ion, and more operators. There are advantages such as control. Radio level convergence networks are available in both col located and non-col located deployments. [092] Through wireless level converged networks, it is easier to support tight ly-coupled management between cell networks and WLANs (for example, WiFi), and transmit delays using characteristics of cell networks and Wi-Fi networks. Procedure steps to reduce (del ay) can be considered.

Retransmission Delay: In the conventional Wi-Fi, retransmission is performed after a backoff time when data transmission fails. At this time, the CW of the backoff is increased exponentially than the conventional one, and since it competes fairly with other STAs, it takes longer to retransmit. In particular, when there are a lot of STAs and a long delay for access, such a retransmission delay may occur seriously. This does not support the quality of service (QoS) requirements of the service and thus does not guarantee the QoS of the terminal. In order to solve this problem, if the data transmitted through the WiFi network fails to transmit, it may be necessary to retransmit the packet more quickly through the saller network without retransmitting through the WiFi network.

Reduced Transmission Delay: The average rate of data split in the cell network can be determined but the dynamic rate is difficult to determine, so certain data branched to the WLAN There is a need for a method that enables faster transmission through the cellular network in case of delayed transmission. Since the data reception delay can be more accurately understood from the point of view of the receiver receiving the actual data, information about the reception delay when the receiver receives the data in the cell network in order to optimize the data transmission rate and increase the system throughput. Etc. may be necessary.

The present invention proposes a method for transmission in a Celler-WiFi (Cel lular / Wi-Fi) wireless level converged network. The present invention proposes a method for faster transmission over a cellular network in which delay occurs or data transmission fails when specific data branched to a WLAN (for example, WiFi) is transmitted through the WLAN. In addition, the present invention proposes a method for increasing system throughput by optimizing the mult i-RAT data transmission rate by using a data reception delay of a receiver receiving actual data. FIG. 6 is a diagram illustrating examples of a structure of a WiFi-Cel hilar converged communication system.

Referring to FIG. 6A, a WiFi-Cellular converged communication system may include a cellular BS and WiFi APs, and the WiFi APs may be connected to the cellular base station through a core network. Referring to FIG. 6B, a WiFi-Cellular converged communication system includes a cellar base station (eel hilar BS) and WiFi APs, and a wireless access is performed between the cellar base station and the WiFi AP through a radio access network (RAN) interface. This is possible. Referring to FIG. 6C, a WiFi-Cel hilar converged communication system includes a cellular BS and WiFi APs. Unlike FIG. 6A, a WiFi-Cel hilar converged communication system is wirelessly connected to a cellular BS through a wireless access network interface. eAP can access the S ᅳ GW MMEC Mobility Management Entity via a core network interface. 6 (refer to 1, the WiFi-Cel lular converged communication system includes a multi-RAT BS supporting both cellular and WiFi communication, the multi-RAT BS can be connected to the S-CT 麗 E through.

[098] Bearer Split refers to the ability to split (or split) a bearer on multiple eNBs, in dual connectivity. When the UE performs dual access between the cell network and the WLAN network, the celller or the AP may configure a bearer of the terminal to simultaneously transmit / receive data of one bearer through the saller and the AP.

FIG. 7 is a diagram illustrating examples not bearer split as radio level integration-radio protocol architectures.

FIG. 7 illustrates a case in which the eNB does not split a bearer for data to be transmitted to the UE and the AP when transmitting data to the UE and the AP. In Alt 1, Alt 2, Alt 3, and Alt 4 shown in FIG. 7, the AP and the eNB do not have bearers in which data is simultaneously transmitted through respective RATs. Bearers transmitted through the AP in Alt 1 ᅳ 2 Is branched through a higher layer of CN (Core Network) or PDCP (Packet Data Convergence Protocol) to transmit data to the MAC side of the AP, and in Alt 3, the eNB transmits data to the MAC side of the AP through the PDCP layer, In Alt 4, the eNB sends data to the MAC side of the AP via the Radio Link Control (RNC) layer. 2 Send.

In the case of a non-col located scenario, an Xn interface between the eNB and the AP needs to be defined. For col located scenarios (physically or logically), the Xn interface is not needed. The adapt ion layer needs to interwork the LTE protocol and WLAN protocol at each alt.

For communication in a dual connect ivi ty situation, the eNB may additionally configure a bearer for WLAN communication in addition to the bearer for data transmission to the terminal through the cell network. That is, the eNB uses separate bearers for data to be transmitted to the terminal and data to be transmitted to the AP through the cell network. FIG. 8 illustrates a case in which the eNB splits bearers for data to be transmitted to the UE and the AP when the eNB transmits data to the UE and the AP. In Alt 5, Al t 6, Alt 7, Alt 8 shown in FIG. 8, the eNB has a separate bearer for data to be transmitted to the AP. Al t 5 is the eNB sends data to the MAC layer of the AP through the upper layer of the Packet Data Convergence Protocol (PDCP), Alt 6 is the eNB sends data to the MAC layer of the AP through the Xn interface in the PDCP layer, Alt 7 transmits data from the RNC (Radio Link Control) layer of the eNB to the MAC of the AP through the Xn interface. Alt 8 transmits data from the MAC layer of the eNB to the MAC terminal of the AP through the Xn interface. As such, when spl it data at the radio level (Radio level), the terminal is not applied in the WLAN (e.g., Wi-Fi), but is applied in the wireless communication system (e.g., LTE) The data security method in the section can be applied, which has the advantage of transmitting / receiving more secure data. In order to apply the security benefits of Cellular-Wi-Fi radio level split (or branch), a procedure for this is defined. A terminal connected to the Cellular communication system is connected to an AP for radio level split. In this case, the initial connection process can be performed faster.

In the present invention, it is assumed that a bearer is split and transmitted to an eNB of a cell network and an AP of a WLAN. In addition, the present invention is RUXRadio Link Control) layer shows that data is forked, but this is for convenience and data can be transmitted / received in the PDCP or MAC layer. Therefore, the sequence number referred to in this patent may be a sequence number in RLC or a sequence number in PDCP, and additionally includes a byte number (or a properly received byte number) for retransmission in one packet or RLC SDU. You can also reduce the overhead that can be caused by retransmission units. In addition, the following drawings are written in downlink (DL), but this is for convenience and may be equally applicable to uplink (UL) transmission in the terminal.

In the present invention, as a retransmission procedure, (1) when the AP determines cel lular retransmission, (2) when the eNB determines cel lul retransmission, (3) the UE requests retransmission to the cell The description will be made by dividing the case, and a fast cell data transmission procedure and a data transmission rate adjustment method will be described.

9, the eNB of a saller network may use branched bearers to transmit data to a terminal. For example, the eNB transmits sequence 1 and 4 (in the drawing, only the number of the sequence) to the terminal through a specific bearer through the cell network, and the sequence 2 and 5 is a cell network network. It transmits through but transmits to the terminal through the branched bearer different from the specific bearer. The eNB transmits the sequence 3 to the AP through the branched bearer, and the AP transmits the sequence 3 to the terminal through the WLAN. In this case, if the terminal fails to receive the third sequence transmitted through the WLAN, a retransmission procedure may be performed as shown in the right figure of FIG. 9.

Looking at the right picture of Figure 9, in the next transmission, the eNB transmits the sequence 6, 9 to the terminal through a specific bearer through the cell network, and the sequence 8 is transmitted through the cell network It transmits to the terminal through the branched bearer different from the specific bearer. In this case, the eNB may retransmit the sequence 3 to the terminal through the branched bearer. As such, when data transmitted by the AP fails to transmit, when a specific condition is satisfied, the AP may retransmit the cell more quickly through the network without retransmitting the data through the WLAN. On the other hand, eNB is 6, 9 When transmitting the sequence, sequence 7 is also transmitted to the AP through the branched bearer, and the AP transmits the sequence 7 to the terminal.

FIG. 10 is a diagram illustrating a procedure when the AP determines a mobile retransmission.

Referring to FIG. 10, an eNB of a saller network may split a bearer at a radio level to transmit and receive data with an AP, and may configure retransmission related configuration for such a bearer branch configuration (conf igurat ion). conf igurat ion) may be transmitted to the AP (S1010). Configuration information related to retransmission of the branched bearer may include the following items 1), 2), and 3).

1) an indicator of whether to support retransmission of downlink data to the terminal of the AP in the eNB of the cell network (the eNB of the cell network supports the retransmission of downlink data to the AP in the cell network) You can enjoy it by sending an indicator that you can give it.)

2) The eNB of the celller network may inform the AP about information on the number of retransmissions through the WLAN network, which is a criterion for performing retransmission from the AP to the celller network. The AP may set the value of the number of retransmissions of data transmitted from the cell network to the maximum number of retransmissions of the AP, or may be independently applied.

3) The eNB of the cellular network may inform the AP of data lifetime information in RLC of the eNB of the cellular network. First, MAC data lifetime related information can be transmitted from the AP to the eNB. The eNB that receives this may determine the RLC data lifespan of the eNB and transmit information about it to the AP. Alternatively, the AP receiving the RLC data lifetime information from the eNB may set its MAC data lifetime to a value less than or equal to the RLC data lifetime.

In addition, when receiving the retransmission related configuration (conf igurat ion) information, the AP may transmit a retransmission setup completion woofer message to the eNB when it is determined to set up retransmission with the eNB of the cell network (S1010).

Subsequently, the eNB of the cellular network may transmit downlink data to the AP through the branch bearer (S1020), and the AP may transmit the downlink data to the UE (UE) through the WLAN (S1030). The UE sends the downlink data to the AP. An ACK / NACK (Acknowl edgement / Negat i ve Acknowledgement) is transmitted to the AP (S1040).

The AP, which receives the ACK / NACK signal for the downlink data from the terminal, may determine whether a predetermined condition for retransmission of the downlink data from the eNB to the terminal through the saller network is satisfied (S1050). . When the AP that performs the retransmission related configuration with the cellular network satisfies a predetermined condition, it may determine to retransmit to the eNB of the cellular network. If the AP has retransmitted downlink data through the AP as many times as retransmissions configured by the eNB of the cell network, the next retransmission may determine to perform the cell network. That is, when the AP retransmits through the WLAN up to a preset maximum number of transmissions, the eNB that has set up retransmission with the eNB of the cell network may determine to retransmit to the eNB of the saler network (without TCP ACK / NACK transmission). In addition, the AP may determine to perform retransmission to the eNB of the cellular network based on the load or measured channel state of the AP as the predetermined condition. The AP may determine to perform retransmission through the network when the load of the AP or a channel load report value transmitted by a specific terminal is greater than or equal to a predefined threshold value. In addition, the AP may determine to perform retransmission through the cell network when a value of a received signal strength indicat ion (RSSI), which is a state of the measured channel, is equal to or less than a predetermined threshold value. In addition, when the access delay of the data retransmitted by the AP is greater than or equal to a predetermined threshold value, the AP may determine to perform retransmission through the cell network. The above methods can be applied individually or in duplicate.

[0117] When the AP determines to perform retransmission of downlink data through the saller network, the AP transmits a retransmission request message requesting retransmission at the RLC or MAC layer of the eNB using an interface between the AP and the eNB. It may be (S1060). This retransmission request message includes a sequence number corresponding to downlink data (RLC PDU (MAC PDU) or MAC PDU), C-RNTI (Cel l Radio Network Temporary Ident if ier) or AID May be included. Receiving a retransmission request message from the AP, the eNB performs scheduling for the UE that fails to receive the PDCP PDU, RLC PDU, or MAC PDU of the specific sequence number requested by the AP, and performs DCI (Downl Ink Control). Informat ion) transmits the format. The eNB retransmits the PDCP / RLC / MAC PDU of a specific sequence number to the UE through the Seller network to the resource scheduled for the UE that failed to receive (S1070).

In FIG. 11, the description of S1110 to S1140 is the same as the description of S1010 to S1040 in FIG. 10 and will be omitted. The AP is responsible for downlink data transmitted from the terminal to the terminal through the branch bearer.

Upon receiving ACK / NACK (Acknowledgement / Negative Acknowledgement), i.e., when the AP transmitting the data of the bearer branched to the eNB of the saller network receives an ACK from the receiver or fails to receive the ACK, the AP An AP STATUS message including ACK / NACK information may be transmitted to the eNB using an interface between the AP and the eNB (S1150). In this case, the AP status message includes an indicator indicating the ACK control, a message length, {CR TI or AID, a sequence number of downlink data requiring retransmission (eg, Sequence Number 1), the number of times the AP retransmits to the terminal, and the terminal. At least one or more of the ACK / NACK signal received from},

Receiving an AP status message from the AP, the eNB may determine to retransmit (R1X / MAC PDU) at the PDCP / RLC / MAC layer in the PDCP / RLC / MAC layer, which is not properly transmitted through the AP (S1160) ). Alternatively, when the information transmitted in the AP status message satisfies a predetermined predetermined condition, it may be decided to retransmit the PDCP / RLC / MAC PDU. For example, when the number of retransmissions is greater than or equal to a predefined threshold value, the eNB of the saller network may retransmit (S1170). Alternatively, when the channel condition of the celller is better than that of the WLAN, the eNB of the celller network may retransmit. The eNB of the cellular network may remove the PDCP / RLC data when receiving an ACK for a predefined time buffering the PDCP / RLC data.

[0121] Next, the terminal may request retransmission to the seller network. When the terminal receives specific data from the AP exceeding a predefined maximum number of retransmissions That is, when the UE performs the retransmission process with the AP a predetermined number of times, the UE recognizes that the link performance with the AP is poor and transmits an RLC status report to the eNB of the cell network. The eNB of the cell network that receives the RLC status report from the terminal may retransmit specific data requested by the terminal in the RLC status report using the eNB of the cell network.

12 is a diagram exemplarily illustrating a procedure for fast cell data transmission in a celller-WLAN converged network.

When delayed transmission of specific data branched to the WLAN through the WLAN can be transmitted faster through the eNB of the network. Referring to the left figure of FIG. 12, the eNB of the saller network may use branched bearers to transmit data to the terminal. For example, the eNB transmits sequences 1 and 4 (only numbers of sequences in the drawing) to the UE through the bearer network through a specific bearer, and sequences 2 and 5 transmit the cell to the cell network. Transmit through the branched bearer different from the specific bearer to the terminal. Then, the eNB transmits the sequence 3 to the AP through the branched bearer, and the AP transmits the sequence 3 to the terminal through the WLAN. The eNB may start a predetermined timer while transmitting downlink data corresponding to the third sequence to the AP. When the UE has not yet received the third sequence when the timer expires, a retransmission procedure may be performed as shown in the right figure of FIG. 12. 12 is the same as the description of the right figure described with reference to FIG. 9 and will be omitted.

[0124] FIG. 13 is a procedure for fast cell-seller data transmission in a saller-WLAN converged network according to FIG. 12, and is a procedure for an AP transmitting data within a specific time.

Referring to FIG. 13, descriptions of S1310 to S1340 are the same as that of S1010 to S1040 in FIG. 10 and will be omitted. In step S1320, unlike the S1120, the eNB starts a predetermined timer while transmitting downlink data (downlink data for a specific sequence number) to the AP. The AP sends a downlink transmission ACK message to the eNB when the AP transmits downlink data to the UE or receives ACK information indicating that the downlink data has been successfully received from the UE. It transmits (S1350). The downlink transmission ACK message may reuse the aforementioned format of the AP status message. In other words, the downlink transmission ACK message may include information included in the aforementioned AP status message. The eNB stops the timer when an ACK for downlink data of a specific sequence number is transmitted in a downlink transmission ACK message received from the AP.

FIG. 14 is a procedure for fast cell-seller data transmission in the cell-seller WLAN converged network according to FIG. 12 for a case where an AP fails to transmit data within a specific time.

When the eNB expires because the channel status of the AP is not good or the data that needs to be transmitted is a lot of data to be transmitted, the AP cannot transmit data of a specific sequence number of the branched bearer transmitted from the cell network to the UE. If the eNB does not receive the downlink data transmission ACK message, the eNB may transmit data of the specific sequence number to the UE.

Referring to FIG. 14, the contents of S1410 to S1420 are the same as the contents of S1010 to S1020 and are omitted. 13 and 14 show that the AP transmits the same downlink transmission ACK message when the AP transmits data to the UE or when the AP indicates ACK information indicating that the UE successfully received downlink data. It may also be defined as a message that distinguishes each case. For example, a DL transmission indication message indicating that the AP has transmitted downlink data to the UE may be newly defined, and the downlink transmission indication message may include a sequence of the last transmitted data. Numbers may be included.

When the eNB of the cell network network decides to transmit downlink data to the AP and transmits downlink data to the AP, and the AP transmits the downlink data for a specific terminal, the eNB of the cell network network Notifying the AP of this fact may prevent the AP from transmitting duplicate data to the UE. To this end, the eNB of the cellular network may transmit a data discard request message for discarding duplicate data to the AP (S1440). In this data discard request message, the _e NB of the cell network is transmitted for a specific terminal. The sequence number of the data may be included. Upon receipt of this, the AP discards data with the same sequence number.

Alternatively, the AP may start a timer and transmit a downlink transmission request message to the _e NB of the cell when the specific data transmission is not transmitted for a predetermined time in a buffer. Upon receiving this, the eNB of the cell network may transmit the sequence number data transmitted in the downlink transmission request message to a specific terminal. In this case, a voice response message indicating that the eNB of the cell network has transmitted data for a specific UE may be transmitted to the AP. The AP receiving the ACK answer message may discard the sequence number data included in the downlink transmission request message.

On the other hand, in the case of data transmitted duplicately from the cell network and the WLAN at the receiving side such as the terminal, the duplicated data may be discarded by using a conventional duplicate detect ion method.

15 is an exemplary diagram for explaining a method of adjusting a data transmission rate in a saller-WLAN converged network.

In the case of the existing core network level bearer branch (CN level bearer Spl it), the saller network determines the ratio of the cellular network and the WLAN branch data in consideration of the load and channel state of each RAT. However, since the data reception delay can be more accurately understood from the receiver side that actually received the data, in order to optimize the data transmission rate and increase the system throughput, the reception delay when the receiver side receives the data from the cell network. Information may be needed.

When receiving a branched bearer data at a receiving side (for example, a terminal), data received from a specific RAT may be rearranged. The receiving side (e.g., the UE) may perform data transmission or data received from a specific RAT for a specific time when the time taken to reorder data received from the specific RAT in a RLC exceeds a predefined threshold value. Information on the sum of reordering time values or a ratio with a specific time (for example, a ratio between T1 and T2) may be transmitted to a transmitting side (for example, eNB and AP). For example, as shown in FIG. 15, T1, which is a time taken to rearrange a specific MAC / RLC PDU, is _.

If a predefined threshold value is exceeded, a split rate control message may be transmitted to the eNB of the cell network. In this split rate control message, a message indicator indicating that it is a branch rate control message, a RAT indicator indicating a specific RAT for which the branch rate needs to be controlled, and a Tl value black Threshold of T1, sequence number to rearrange, etc. can be transmitted.

As another example, the receiving side (eg, the terminal) may determine the sum of rearrangement times of data received from a specific RAT (eg, T1 + T2) or a ratio of rearrangement times (for a specific T time). For example, the ratio between T1 and T2) can be periodically transmitted to the transmitting side and enjoyed. In such a branch rate control message, a message indicator indicating that it is a branch rate control message, a RAT indicator indicating a specific RAT to which the branch rate needs to be controlled, (Tl + T2) / T or (Tl-threshold + T2-threshold) / T or T1 + T2, sequence numbers (3, 8) that need to be rearranged can be sent. In this case, the period may additionally transmit information about the bearer branch configuration (bearer spl it conf igurat ion). In particular, a period can be added in case of real-time data that is sensitive to latency.

[0136] The transmitting side (e.g., eNB) receiving the branch rate control message from the receiving side (e.g., the terminal) takes into account characteristics of each RAT in case of data sensitive to latency among data of a specific RAT. The ratio of the split data of each RAT can be adjusted. For example, if a cell rearrangement of the data transmitted by the eNB of the eNB to the AP is long, the ratio of data transmitted by the eNB to the AP through the WLAN is lowered based on the branch rate control message information transmitted by the UE. You can increase the rate at which data is sent over the network.

Embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some components and / or features to constitute an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Part of an embodiment Configurations or features may be included in other embodiments, or may be substituted for alternative configurations or features of other embodiments. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Industrial Applicability

[0139] A method and apparatus for retransmitting data by a base station of a first communication system in a network interworking with a plurality of communication systems are available industrially in an LTE / LTE-A system, which is an example of a wireless communication system.

Claims

[Range of request]

[Claim 1]

In a method in which a base station of a first communication system retransmits data in a network in which a plurality of communication systems interwork,

Transmitting information related to retransmission of downlink data to be transmitted by using a bearer branched at a radio level to transmit and receive data between a base station of the first communication system and a base station of the second communication system, to the base station of the second communication system;

When the information related to retransmission of downlink data to be transmitted using the bearer branched to the radio level indicates that the base station of the first communication system performs retransmission, an acknowledgment answer for the indication is sent to the second communication system. Receiving from a base station;

Transmitting downlink data to a base station of the second communication system based on the confirmation answer; And

And retransmitting the downlink data to the terminal if a predetermined condition is satisfied, wherein the base station of the first communication system retransmits the data in a network interworking with a plurality of communication systems.

[Claim 2]

The method of claim 1,

Information related to retransmission of downlink data to be transmitted using a bearer branched to the radio level may include a condition for performing retransmission in the first communication system or a PDCKPacket Data Convergence Protocol of a base station of the first communication system of the downlink data. And re-transmitting data by a base station of a first communication system in a network interworking with a plurality of communication systems, including life information in a Radio Link Control (RLC) or Medium Access Control (MAC) layer.

[Claim 3]

The method of claim 2,

The condition for performing the retransmission in the first communication system includes a number of retransmissions of the downlink data of the base station of the second communication system. A method for retransmission of data by a base station of a first communication system in a network interworking with a communication system.

[Claim 4]

The method of claim 1,

When the predetermined condition is satisfied, the base station of the first communication system in a network interworking with a plurality of communication systems includes receiving a message for requesting retransmission of the downlink data from a base station of the second communication system. How to resend data.

[Claim 5]

The method of claim 1,

The case where the predetermined condition is satisfied includes a case where the ACK signal for the downlink data is not received until the timer started by transmitting the downlink data to the second communication system expires. A method for retransmission of data by a base station of a first communication system in a network to which a system interworks.

[Claim 6]

The method of claim 4,

Wherein the message includes a sequence number of the downlink data, wherein the base station of the first communication system retransmits data in a network interworking with a plurality of communication systems.

[Claim 7]

The method of claim 4, wherein

The message is received from the base station of the second communication system when the second communication system retransmits the downlink data a predetermined number of times but the terminal does not receive it successfully. 1 A method in which a base station of a communication system retransmits data.

[Claim 8]

The method of claim 1,

Wherein the first communication system is a cellular communication system and the second communication system is a wireless local area network (WLAN) communication system. A method for retransmission of data by a base station of a first communication system in a network interworking with a communication system.

[Claim 9]

A base station of a first communication system for retransmitting data in a network in which a plurality of communication systems work together,

A transmitter configured to transmit, to a base station of the second communication system, information related to retransmission of downlink data to be transmitted by using a bearer branched at a radio level to transmit and receive data between a base station of the first communication system and a base station of the second communication system. ;

When the information related to the retransmission of the downlink data to be transmitted using the bearer branched to the radio level indicates that the base station of the first communication system performs the retransmission, the acknowledgment of the indication is sent to the second communication system. A receiver configured to receive from a base station;

The transmitter is configured to transmit downlink data to a base station of the second communication system based on the acknowledgment answer, and includes a processor for controlling the transmitter to retransmit the downlink data to a terminal when a predetermined condition is satisfied. A base station of a first communication system.

[Claim 10]

The method of claim 9,

And when the predetermined condition is satisfied, receiving a message for requesting retransmission of the downlink data from a base station of the second communication system.

[Claim 111]

The method of claim 9,

The case where the predetermined condition is satisfied includes a case in which an ACK signal for the downlink data is not received until a timer started by transmitting the downlink data to the low 1-2 communication system expires. Base station of a communication system.

[Claim 12] The method of claim 10,

The message comprises a sequence number of the downlink data.

[Claim 13]

The method of claim 9,

Wherein the first communication system is a cellular communication system and the second communication system is a wireless local area network (WLAN) communication system.

[Claim 14]

The method of claim 10,

The message comprises a sequence number of the downlink data.