KR20160109921A - Apparatus and method for signal scheduling in wireless communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for signal scheduling in a wireless communication system. The apparatus according to the present invention includes a scheduler that is implemented in a MAC layer of a structure of a radio interface protocol and schedules a carrier wave of a licensed band and a license-exempt band. When the sub- And a scheduling processor for selecting a sub-carrier added to the license-exempt band based on the monitoring result of the monitoring unit. do.

Description

[0001] Apparatus and method for signal scheduling in wireless communication systems [

The present invention relates to an apparatus and method for signal scheduling in a wireless communication system.

The terminal UE communicates by collecting a plurality of licensed band carriers and a plurality of unlicensed band carriers. The license band carrier, which is relatively easy to guarantee QoS, carries GBR traffic. The license-exempt band carrier, which is difficult to guarantee QoS, Used for traffic.

On the other hand, a license-exempt band carrier operating in the form of a LBT (listen before talk), if there is traffic to be sent for the corresponding carrier band but before checking whether there is a signal already occupied before sending, wait for the backoff time, Since the UE can transmit its own data if it is sent, it is difficult to guarantee the QoS and it is used in the form of subcarrier for non-GBR traffic.

In addition, when the base station and the terminal aggregate and use several carriers, it is difficult to satisfy the QoS requested by the terminal using the license-exempt band subcarrier in the license-exempted band operated in the LBT form, It is used in subcarrier form for GBR traffic.

Therefore, there is a need for a scheme that can support the user's QoS while using the license-exempt subcarrier.

Japanese Patent Application Laid-Open No. 10-2013-0109179

It is an object of the present invention to provide an apparatus and method for signal scheduling in a wireless communication system for selecting a suitable subcarrier by monitoring HARQ RTT, load status, and signal strength status in order to satisfy a QoS requirement of a user in selecting a subcarrier in a license- .

The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

In order to achieve the above object, a signal scheduling apparatus of a wireless communication system according to the present invention may be implemented in a MAC layer of a structure of a radio interface protocol, and may include a scheduler for scheduling a carrier wave in a licensed band and a license- .

Here, the scheduler includes a monitoring unit for monitoring a cell level retransmission time (Hybrid ARQ Round Trip Time), a cell level load state, and a signal strength state for a carrier wave in a license-exempt band when a sub-carrier is added to the license- And a scheduling processor for selecting sub-carriers to be added to the license-exempt band based on the monitoring result of the monitoring unit.

According to the present invention, when a sub-carrier of a license-exempted band is selected, an HARQ RTT, a load state, and a signal strength state are monitored to select an appropriate sub-carrier.

1 is a diagram illustrating a structure of a wireless interface protocol to which a signal scheduling apparatus of a wireless communication system according to the present invention is applied.
2 is a block diagram of a signal scheduling apparatus of a wireless communication system according to the present invention.
FIG. 3 is a flowchart illustrating a signal scheduling method of a wireless communication system according to the present invention.
4 is a diagram illustrating a computing system to which the apparatus according to the present invention is applied.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the difference that the embodiments of the present invention are not conclusive.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

1 is a diagram illustrating a structure of a wireless interface protocol to which a signal scheduling apparatus is applied in a wireless communication system according to the present invention.

FIG. 1 shows a structure of a radio interface protocol between a UE based on the 3GPP radio access network standard and a UMTS Terrestrial Radio Access Network (UTRAN).

The wireless interface protocol of the wireless communication system according to the present invention includes a physical layer, a data link layer, and a network layer, and vertically includes a control plane Plane) and a user plane for data information transmission (User Plane). The protocol layers of FIG. 1 are divided into a first layer (L1), a second layer (L2), a third layer (L2), and a third layer (L2) based on the lower three layers of an Open System Interconnection (L3).

First, there is a Radio Resource Control (RRC) layer 10 in the third layer. The RRC layer 10 provides an information broadcast service for broadcasting information to all mobile stations located in an arbitrary area.

The RRC layer 10 is defined only in the control plane and controls the logical channels, the transport channels and the physical channels in connection with the configuration, re-configuration and release of radio bearers (RBs) . Here, the RB means a service provided by the second layer for data transmission between the UE and the UTRAN.

The second layer includes a Packet Data Convergence Protocol (PDCP) layer 20, a Radio Link Control (RLC) layer (MAC) layer 30 and a Medium Access Control (MAC) layer 40 may be present.

The PDCP layer 20 performs header compression to reduce an IP packet header size, which is relatively large in size and contains unnecessary control information, for efficient transmission in an RF interval with a small bandwidth in transmitting IP packets such as IPv4 or IPv6. ) And termination, transmission of user data, and maintenance of the sequence number for the radio bearer. The PDCP layer 20 uses a service provided by the lower RLC layer 30. [

The RLC layer 30 provides a radio link setup and release service. Also, it performs a segmentation and reassembly function related to an RLC service data unit (SDU) descending from the upper layer of the user plane.

The MAC layer 40 provides a service to the RLC layer 30, which is an upper layer, through a logical channel. At this time, various logical channels can be provided according to the type of information transmitted from the MAC layer 40. [ Meanwhile, the function of the RLC layer 30 may be implemented as a functional block in the MAC layer 40. [ In this case, the RLC layer 30 may not exist.

In addition, the MAC layer 40 may provide a reallocation service of radio resources and MAC parameters to the RRC layer 10. This service is performed when the RRC requests reassignment of a radio resource or requests a MAC parameter change.

A physical layer 50 may exist in the first layer. The physical layer 50 provides an information transfer service to an upper layer using a physical channel. For example, the physical layer is connected to the upper layer MAC layer 40 through a transport channel, and data is transferred between the MAC layer 40 and the physical layer through the transport channel. Data can be moved between the different physical layers, that is, between the transmission side and the reception side physical layer through the physical channel.

The transport channel can be divided into a dedicated transport channel (DTCH) and a common transport channel (CTCH) depending on whether the mobile station is used exclusively or shared by a plurality of mobile stations. have.

On the other hand, the MAC layer 40 may include a scheduler 100. The scheduler 100 may schedule a carrier wave of a license-exempt band and select a subcarrier to be added to the license-exempt band. The scheduler 100 monitors a cell level retransmission time (HARQ RTT), a cell level load status, a signal strength status, and the like of a carrier wave in a license-exempted band, Can be selected.

The scheduler 100 will now be described with reference to the embodiment of FIG.

2 is a block diagram of a signal scheduling apparatus of a wireless communication system according to the present invention.

2 is a diagram illustrating a configuration of a scheduler existing in the MAC layer of the structure of the air interface protocol according to the present invention. Hereinafter, the scheduler of FIG. 1 will be referred to as a 'scheduling device' The same reference numerals as those in FIG.

The scheduling apparatus 100 illustrated in FIG. 2 may include an interface processor 110, a scheduling processor 130, and a monitoring unit 150.

Specifically, the interface processing unit 110 may include an RRC interface processing unit 111, an RLC interface processing unit 113, a license sub-carrier physical interface processing unit 115, and a license-exempt sub-carrier physical interface processing unit 117.

Here, the RRC interface processor 111 supports transmission and reception of signals with the RRC layer, and the RLC interface processor 113 supports transmission and reception of signals with the RLC layer. In addition, the license sub-carrier physical interface processor 115 supports signal transmission and reception with the license-band carriers of the physical layer, and the license-exempt sub-carrier physical interface processor 117 supports signal transmission and reception with the license-unlicensed band carriers of the physical layer.

The scheduling processing unit 130 may include an uplink scheduling processing unit 131 and a downlink scheduling processing unit 133.

The uplink scheduling processor 131 performs scheduling for an uplink transmission channel for transmitting data from the UE to the network. The uplink transmission channel includes a RACH (Random Access Channel) for transmitting an initial control message and an uplink SCH (Shared Channel) for transmitting user traffic or control messages. Here, the uplink SCH may be classified into a UL L1 / L2 control channel for transmitting control information related to a UL-SCH for transmitting actual traffic and a method for processing traffic received through the UL-SCH. The latter control information is referred to as UL scheduling information (UpLink Scheduling Information) in particular.

The UL scheduling information includes information such as identifier information, radio resource allocation information, Duration of assignment information, and transmission parameters such as multi-antenna information, modulation information, and payload size, .

Meanwhile, the downlink scheduling processor 133 performs scheduling for a downlink transmission channel for transmitting data from the network to the UE. The downlink transmission channel includes a BCH (Broadcast Channel) for transmitting system information and a downlink SCH (Shared Channel) for transmitting user traffic and control messages. In case of a traffic or control message of a downlink multicast or broadcast service, it may be transmitted through a downlink SCH, or may be transmitted via a separate downlink multicast channel (MCH). Here, the downlink SCH may be classified into a DL L1 / L2 control channel for transmitting control information related to a DL-SCH for transmitting user traffic and a method for processing user traffic received through the DL-SCH. The latter control information is called DL scheduling information (Downlink Scheduling Information) in particular.

The DL scheduling information includes information such as identifier information such as a group identifier and / or a terminal identifier, radio resource allocation information for allocating radio resources such as time / frequency, an allocation period (Duration control information such as multi-antenna information, modulation information, payload size, asynchronous HARQ information, synchronous HARQ information, and the like, including information on the assignment information of the MIMO scheme or the beamforming scheme, May be included. Here, the asynchronous HARQ information includes a HARQ process number, a redundancy version (RV), a new data indicator, and the like, and the synchronous HARQ information includes a retransmission sequence number .

The monitoring unit 150 may include a retransmission time monitoring unit 151, a load status monitoring unit 153, and a signal strength status monitoring unit 155.

The retransmission time monitoring unit 151 monitors the length of the cell level retransmission time (HARQ RTT) for the plurality of unlicensed carrier waves (Component Carriers) and stores the monitoring result. At this time, the length information of the cell level retransmission time for the carriers in the license-exempt band may be transmitted to the UL scheduling processor 131 and the DL scheduling processor 133 and used to select the subcarrier.

The load status monitoring unit 153 monitors the cell level load status of the plurality of license-exempted carriers and stores the monitoring result. At this time, the cell level load state information for the carriers in the license-exempted band can be transmitted to the UL scheduling processor 131 and the DL scheduling processor 133 and used for selecting subcarriers.

The signal strength state monitoring unit 155 monitors the signal strength states of the plurality of unlicensed band carriers and stores the monitoring result. Here, the signal strength state monitoring unit 155 monitors the cell level signal strength values of the plurality of unlicensed band carriers reported from the UE. At this time, the cell level signal strength state information for the carriers in the license-exempted band can be transmitted to the UL scheduling processor 131 and the DL scheduling processor 133 and used for selecting subcarriers.

The UL scheduling processing unit 131 and the DL scheduling processing unit 133 receive the length information of the cell level retransmission time for the carriers of the license-exempt band from the retransmission time monitoring unit 151, the LOAD status monitoring unit 153, Level signal state information on carriers in the license-exempt band from the signal strength status monitoring unit 155, and transmits the cell-level signal strength state information to the cell-level signal strength state information for the license- Band subcarriers can be selected.

For example, the UL scheduling processor 131 may collect retransmission time length information from the retransmission time monitoring unit 151 when it is necessary to add a subcarrier in a license-exempted band, and transmit the subcarrier list satisfying a predetermined QoS according to the retransmission time length . At this time, the uplink scheduling processing unit 131 collects the load state information from the load state monitoring unit 153, and extracts sub-carriers satisfying the pre-defined QoS according to the load state among the generated sub-carrier list.

Also, the uplink scheduling processor 131 collects signal strength state information from the signal strength state monitoring unit 155, and selects a subcarrier having the highest signal strength among the extracted subcarriers, and adds the subcarrier to the license-exempted band.

The downlink scheduling processor 133 can also select sub-carriers added to the license-exempt band by the same operation as that of the uplink scheduling processor 131. [

Accordingly, the scheduling apparatus 100 according to the present invention can satisfy the QoS of the user by adding the license-exempt band subcarrier since all of the retransmission time length, the load state, and the signal strength state are considered when selecting the subcarrier in the license-exempt band .

The operation flow of the scheduling apparatus according to the present invention will now be described in more detail.

FIG. 3 is a flowchart illustrating a signal scheduling method of a wireless communication system according to the present invention.

3, when a sub-carrier is required to be added to the license-exempted bandwidth of the uplink channel and / or the downlink channel (S110), the scheduling device transmits the carriers of the license-exempt band through the retransmission time monitoring unit 151 shown in FIG. Level information of the cell level retransmission time (HARQ RTT) with respect to the cell-level retransmission time (S 120).

At this time, the scheduling apparatus generates a sub-carrier list in which the length of the cell level retransmission time for the carriers of the license-exempt band collected in the process of 'S120' satisfies the predetermined QoS (S130).

Thereafter, the scheduling apparatus collects cell level load status information on carriers in the license-exempt band through the load status monitoring unit 153 shown in FIG. 2 (S140). At this time, the scheduling device extracts the sub-carriers satisfying the QoS defined in the load state collected in the process 'S140' among the sub-carrier list generated in the process 'S130' (S150).

Finally, the scheduling apparatus collects cell level signal strength status information on carriers in the license-exempt band through the signal strength status monitoring unit 155 shown in FIG. 2 (S160). At this time, the scheduling apparatus selects the subcarrier having the highest signal strength state collected in the step S160 among the subcarriers extracted in the step S150 (S170), and adds the selected subcarrier to the license-exempted band (S180).

The steps 'S110' to 'S180' may be applied to the uplink and downlink, respectively.

4 is a diagram illustrating a computing system to which the apparatus according to the present invention is applied.

4, a computing system 1000 includes at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, (1600), and a network interface (1700).

The processor 1100 may be a central processing unit (CPU) or a memory device 1300 and / or a semiconductor device that performs processing for instructions stored in the storage 1600. Memory 1300 and storage 1600 may include various types of volatile or non-volatile storage media. For example, the memory 1300 may include a ROM (Read Only Memory) and a RAM (Random Access Memory).

Thus, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by processor 1100, or in a combination of the two. The software module may be implemented in a computer-readable medium such as RAM, flash memory, SRAM, ROM, programmable ROM, EEPROM, register, hard disk, removable disk, CD-ROM, Or may reside in the same storage medium (i.e., memory 1300 and / or storage 1600). An exemplary storage medium is coupled to the processor 1100, which can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor 1100. [ The processor and the storage medium may reside within an application specific integrated circuit (ASIC). The ASIC may reside within the user terminal. Alternatively, the processor and the storage medium may reside as discrete components in a user terminal.

In addition, the network interface 1700 may include a module for a wireless Internet connection or a module for short range communication. Here, the wireless Internet technology includes a wireless LAN (WLAN), a wireless broadband (Wibro), a Wi-Fi, a World Interoperability for Microwave Access (WIMAX), a High Speed Downlink Packet Access ), Etc., and the short range communication technology may include Bluetooth, ZigBee, UWB (Ultra Wideband), RFID (Radio Frequency Identification), Infrared Data Association (IrDA) have. The wired communication technology may include USB (Universal Serial Bus) communication and the like.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

10: RRC layer 20: PDCP layer
30: RLC layer 40: MAC layer
50: Physical (PHY) layer 100: Scheduler
110: Interface processor 111: RRC interface processor
113: RLC interface processor
115: License sub-carrier physical interface processor
117: License-exempt subcarrier physical interface processor
130: Scheduling processor 131: Uplink scheduler
133: downlink scheduling processing unit 150:
151: retransmission time monitoring unit 153: load status monitoring unit
155: Signal strength status monitoring section

Claims (1)

An apparatus for signal scheduling in a wireless communication system,
And a scheduler implemented in a MAC layer of a structure of a radio interface protocol to schedule a carrier in a license band and a license-exempt band,
The scheduler comprising:
A monitoring unit for monitoring a cell level retransmission time (Hybrid ARQ Round Trip Time), a cell level load status and a signal strength status of a carrier wave in a license-exempt band when a sub-carrier is added to the license-exempt band; And
And a scheduling processor for selecting a sub-carrier added to the license-exempt band based on the monitoring result of the monitoring unit
And a signal scheduling unit for scheduling the signal in the wireless communication system.

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