KR20160088511A - Apparatus and method of tracking area update for MTC UEs - Google Patents

Abstract

The present invention provides a tracking area updating method for a terminal supporting a low complexity UE category/type for a machine type communication (MTC) operation or a coverage enhancement operation in a 3GPP LTE/LTE-A. The method for tracking a terminal comprises the step of tracking a tracking area update according to a coverage level change. A page message for the terminal is provided as a page message for a normal LTE terminal, an MTC terminal and a CE terminal, respectively.

Description

[0001] Apparatus and method for tracking area update for MTC UE [0002]

The present invention proposes a tracking area update method for UEs supporting low complexity UE category / type or coverage enhancement operation for MTC (Machine Type Communication) operation in 3GPP LTE / LTE-A system.

The method includes the steps of tracking a tracking area update according to a change in a coverage level, the page message including a paging message for a normal LTE terminal, a paging message for a MTC terminal, And a paging message for the terminal is separately configured.

1 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
2 is a block diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

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 numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Herein, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In this specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, the MTC terminal may refer to a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

In other words, the MTC terminal in this specification may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC-related operations. Alternatively, the MTC terminal may support enhanced coverage over the existing LTE coverage or a UE category / type defined in the existing 3GPP Release-12 or lower that supports low power consumption, or a newly defined Release-13 low cost low complexity UE category / type.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.

That is, the base station or the cell in this specification is interpreted as a comprehensive meaning indicating a partial region or function covered by BSC (Base Station Controller) in CDMA, NodeB in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.

Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) a device itself providing a megacell, a macrocell, a microcell, a picocell, a femtocell, or a small cell in relation to a wireless region, or ii) the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a megacell, a macrocell, a microcell, a picocell, a femtocell, a small cell, an RRH, an antenna, an RU, a low power node (LPN), a point, an eNB, Quot;

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In a system such as LTE and LTE-A, the uplink and downlink are configured based on one carrier or carrier pair to form a standard. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.

On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmission / reception points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multiplex transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiplex transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.

In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.

That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.

Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.

Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of a PDSCH, A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

According to the terminal tracking method in the conventional 3GPP LTE / LTE-A system, any LTE / LTE-A terminal receives a TAI (Tracking Area Identity) list from the MME when registering the network. The TAI is determined by a mobile country code (MCC), a mobile network code (MNC), and a tracking area code (TAC), and when an idle terminal moves to a new cell, a TAI And compares the TAI value determined according to the value of the TAI list with the TAI list and performs a TAU (Tracking Area Update) when the TAI list is not stored in the corresponding terminal.

 [Low complexity UE category / type for MTC operation]

As the LTE network spreads, mobile operators want to minimize the number of Radio Access Terminals (RATs) to reduce network maintenance costs. However, conventional MTC products based on a GSM / GPRS network are increasing, and MTC using a low data rate can be provided at low cost. Therefore, there is a problem in that two RATs must be operated respectively, since LTE network is used for general data transmission and GSM / GPRS network is used for MTC. Therefore, Of the total revenue.

To solve this problem, it is necessary to replace a cheap MTC terminal using a GSM / EGPRS network with an MTC terminal using an LTE network. To achieve this, a low complexity UE category that reflects various requirements for lowering the price of an LTE MTC terminal There is a need for the definition of / type and the need for standard techniques to support it.

In addition, about 20% of MTC terminals supporting MTC services such as smart metering are installed in a 'Deep indoor' environment such as a basement. Therefore, for successful MTC data transmission, the coverage of LTE MTC terminals is compared with the coverage of conventional LTE terminals It should be improved by about 15 dB. Also, if the performance degradation due to introduction of the low complexity UE category / type for the MTC operation is additionally considered, the coverage of the LTE MTC terminal should be improved by more than 15dB.

Various methods for robust transmission such as PSD boosting or low coding rate and time domain repetition are considered for each physical channel in order to improve the coverage while lowering the price of the LTE MTC terminal.

Specifically, the requirements of low complexity UE category / type for MTC operation are as follows.

■ Reduced UE bandwidth of 1.4 MHz in downlink and uplink.

 ◆ Bandwidth reduced UEs should be able to operate within any system bandwidth.

 ◆ Frequency multiplexing of bandwidth reduced UEs and non-MTC UEs should be supported.

 ◆ The UE only needs to support 1.4 MHz RF bandwidth in downlink and uplink.

■ Reduced maximum transmit power.

■ Reduced support for downlink transmission modes.

● further UE processing relaxations

 ◆ Reduced maximum transport block size for unicast and / or broadcast signaling.

 ◆ Reduced support for simultaneous reception of multiple transmissions.

◆ Relaxed transmit and / or receive EVM requirements including restricted modulation scheme. Reduced physical control channel processing (e.g., reduced number of blind decoding attempts).

◆ Reduced physical data channel processing (e.g., relaxed downlink HARQ time line or reduced number of HARQ processes).

◆ Reduced support for CQI / CSI reporting modes.

      ● Target a relative LTE coverage improvement? corresponding to 15 dB for FDD? for the UE category / type defined above and other UEs operating delay tolerant MTC applications with respect to their respective nominal coverage.

     ● Provide power consumption reduction for the UE category / type defined above, both in normal coverage and enhanced coverage, to target ultra-long battery life:

In the present invention, for convenience of description, the existing LTE terminal is referred to as a normal LTE terminal, and a new low complexity UE category / type satisfying the above conditions for the MTC operation will be simply referred to as an MTC terminal. Also, the normal LTE terminal or the MTC terminal supporting the coverage enhancement function or mode is referred to as a CE (coverage enhanced) terminal.

In case of the CE terminal, the extent of coverage enhancement required according to the radio channel environment may be different. For example, a coverage level required according to a wireless channel environment for each CE terminal may be defined, and a separate repetition technique or power boosting may be applied to each coverage level. When a plurality of coverage levels are defined in one cell and a radio control channel / wireless data channel is transmitted by applying repetition and power boosting to each coverage level, even if a terminal belongs to one cell It may be effective to vary the paging message or the paging indication channel transmission method depending on the coverage level to which the terminal belongs. In order to do this, it is necessary to group the paging message and the paging message separately for each coverage level between idle terminals camping on the same cell. For this, if the coverage level of an idle terminal belonging to the same cell is changed, a method for indicating this to the base station or the MME is required. That is, if the coverage level is changed even though it belongs to the same cell, it needs to be indicated to the base station and the MME through a tracking area update. However, according to the current tracking area update operation method, there is no way to trigger the tracking area update according to the variation of the coverage level. Specifically, according to the presently defined tracking area update method, when the UE in the idle mode is moved to a new cell through cell reselection outside the area of the current camping cell, If the TAI of the corresponding cell derived through the TAC received through the system information is not in the TAI list stored in the corresponding UE, the tracking area update is performed. When moving within the same cell, tracking area update triggering does not occur because the TAI does not change even if the coverage level of the terminal changes.

In the present invention, a method for performing a tracking area update when a coverage level changes as an idle CE terminal moves within a cell is proposed.

In the present invention, in constructing a paging message for the MTC terminal or the CE terminal, the paging message for the normal LTE terminal, the paging message for the MTC terminal, and the paging message for the CE terminal are separately configured in the base station, We propose the update method.

In particular, in constructing a paging message for CE terminals, we propose a tracking area update method for constructing a separate paging message according to coverage level. Here, the coverage level is a value defined by quantizing based on the degree of coverage enhancement required according to the radio channel condition, and the repetition frequency or the power boosting value of the radio channel transmitted according to the coverage level may be changed. Also, the tracking area update method proposed by the present invention can be applied regardless of the specific radio control channel / data channel transmission method according to the coverage level and the coverage level defined for the CE terminal.

Solution 1. Coverage level Very separate TAI  Assignment

In this scheme, we propose a scheme to set different values of TAC transmitted through SIB (System Information Block) according to coverage level in order to allocate separate TAI according to coverage level to which terminal belongs even in same cell.

For this purpose, new MTC SIBs (System Information Blocks) for MTC terminal and CE terminal are defined. However, in order to allocate different TAC values for different coverage levels, MTC SIBs including the same information area are configured to independently transmit corresponding MTC SIBs using different radio resources according to their coverage levels. That is, if the coverage level supported by the corresponding cell for an arbitrary MTC-specific SIBx (where x is an arbitrary zero or a positive integer) supports four levels of coverage levels of 0, 1, 2, and 3, , MTC SIBx for coverage level 0, MTC SIBx for coverage level 1, MTC SIBx for coverage level 2, and MTC SIBx for coverage level 3 are separately configured and transmitted.

MTC SIBs are defined with coverage common system regardless of coverage level, and coverage-specific MTC SIBs composed of system information that can have different values according to coverage level are defined, and coverage common MTC SIBs can be defined to be transmitted considering the reception performance of the terminals at the worst coverage level, and only the coverage-specific MTC SIBs can be defined to be transmitted separately according to the coverage level. In this case, the corresponding TAC may be included in the coverage-specific MTC SIB.

As described above, by transmitting all or some MTC SIB (s) separately according to the coverage level, the TAC value included in the MTC SIB (s) transmitted for each coverage level can be set differently, It is possible to define that a separate TAI value for the terminal is set. However, in this case, when setting a TAI list for a certain CE terminal, it is possible to define not to include one or more TAI values set for each coverage level in the same cell at the same time in the TAI list for the corresponding CE terminal.

If the CE terminal is defined as above, if the CE terminal changes its coverage level in the corresponding cell even if it does not deviate from the cell coverage currently camping on, the CE terminal may transmit the tracking area update. In this case, when the tracking area update is performed, the UE can define the cell ID of the corresponding cell in the BS and the coverage level to which the corresponding cell belongs in the corresponding cell.

In addition, all types or coverage MTC SIB (s) and coverage-specific MTC SIB (s) defined to transmit MTC SIB (s) through separate radio resources according to coverage level, as described above, The MTC SIB (s) and the coverage area of the MTC SIB (s) can be included in the scope of the present invention. There is no restriction. That is, the information area included in the coverage-specific MTC SIB (s) is not limited to the TAC, and is a method for constructing all system information that can be set differently according to the coverage level, such as the PRACH configuration information. All cases where the MTC SIB is separately transmitted according to the coverage level or the coverage common MTC SIB and the coverage specific MTC SIB are separately defined can be included in the scope of the present invention.

2. Define to perform TAU (tracking area update) when changing coverage level regardless of TAI variation.

If it is defined that a separate TAI is not assigned according to a coverage level within one cell or that an MTC SIB is transmitted / received through the same radio resource region regardless of a coverage level, Can be defined to perform a tracking area update when the coverage level is changed regardless of the TAI update according to the TAC received through the corresponding system information. However, in this case, the coverage level may be determined by the channel measurement result based on the DL reference signal or the number of repetitive reception of the channel until the PBCH and SIB decoding succeeds, but the coverage level determination method is not limited thereto Do not.

Also, in case of applying the method 2 of the present invention, as in the above-mentioned method 1, the coverage level to which the UE belongs can be indicated to the BS in the TAU process.

In the present invention, a paging indication channel for paging message transmission and a paging message transmission / reception method are not limited, and all of the paging indication channels defined for triggering tracking area update for an arbitrary CE terminal, . ≪ / RTI >

1 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Referring to FIG. 1, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 controls the overall operation of the BS according to the tracking area update when the coverage level changes as the CE terminal in the idle state necessary for performing the above-described present invention moves within the cell.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

2 is a block diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

2, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiving unit 1110 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, the controller 1120 controls the overall operation of the UE according to the tracking area update when the coverage level is changed as the CE terminal in the idle state necessary for performing the above-described present invention moves within the cell.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through the corresponding channel.

The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and some of the standard documents is added to or contained in the scope of the present invention, as falling within the scope of the present invention.

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.

Claims (1)

A method for tracking a terminal,
Tracking the tracking area update in accordance with the change in coverage level,
The page message for the UE is configured separately from the paging message for the normal LTE UE, the paging message for the MTC UE, and the paging message for the CE UE.

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