KR20140101652A

KR20140101652A - Method and Apparatus of Radio Resource Management Measurement in Mobile Communication Network

Info

Publication number: KR20140101652A
Application number: KR1020130048785A
Authority: KR
Inventors: 김선우
Original assignee: 인텔렉추얼디스커버리 주식회사
Priority date: 2013-02-12
Filing date: 2013-04-30
Publication date: 2014-08-20

Abstract

The present invention relates to an RRM measurement method in a carrier whereby a control area including PDCCH is not existed, and an apparatus thereof. According to an embodiment of the present invention, a method to enable a base station to measure the RRM of a mobile communication network comprises the steps of: enabling the base station to transmit a message indicating the RRM measurement of the carrier to a terminal; transmitting a signal necessary to measure the RRM of the carrier; and receiving the RRM measurement report from the terminal. The carrier does not include the control channel. The signal is measured using CRS, CSI-RS, TRS, DM-RS, PSS, SSS, or a reference signal by an upper layer signaling.

Description

TECHNICAL FIELD The present invention relates to a method and an apparatus for measuring RRM in a mobile communication network,

The present invention relates to a method and an apparatus for measuring RRM in a carrier in which a control region including a PDCCH does not exist.

As communications systems evolved, consumers, such as businesses and individuals, used a wide variety of wireless terminals. In a mobile communication system such as the current 3GPP family Long Term Evolution (LTE) and LTE-A (LTE Advanced), a high-speed and large-capacity communication system capable of transmitting and receiving various data such as video and wireless data, , It is required to develop a technology capable of transmitting large-capacity data based on a wired communication network. As a method for transmitting a large amount of data, a method of efficiently transmitting data through a plurality of element carriers can be used.

In this system, the time-frequency resource is divided into a region for transmitting a control channel (for example, a physical downlink control channel (PDCCH)) and a region for transmitting a data channel (for example, a Physical Downlink Shared CHannel (PDSCH) .

In order to improve the performance of a wireless communication system, technologies such as Multiple-Input Multiple-Output (MIMO) and Coordinated Multi-Point Transmission / Reception (CoMP) have been considered.

In the NCT (New Carrier Type) where there is no control area including the PDCCH added as a new work item to 3GPP Rel-12, the main issue of PSS / SSS and DM-RS collision problem, RRM measurement for NCT (Radio Resource Management measurement, synchronized new carrier).

The present invention makes it possible to perform RRM measurements on a control channel, that is, a carrier on which the control area is not transmitted, called a so-called NCT.

When the present invention is implemented, if the RRM is measured for the NCT carrier, the base station can instruct the terminal to add or remove the corresponding carrier using the measured result.

Further, the present invention can overcome the limitation of the RRM measurement due to the absence of the control channel in the NCT.

A method for measuring RRM of a mobile communication network according to an exemplary embodiment of the present invention includes transmitting a message instructing RRM measurement of a carrier to the MS, transmitting a signal required for RRM measurement of the carrier, And receiving the RRM measurement report from the terminal, wherein the carrier is a carrier that does not include a control channel and the signal is a CRS, a CSI-RS, a TRS, a DM-RS, a PSS, And the reference signal by the signaling.

A method for measuring RRM of a mobile communication network according to another embodiment of the present invention includes receiving a message instructing RRM measurement of a carrier from a base station, receiving a signal required for RRM measurement of the carrier, Performing a RRM measurement on the carrier using a signal and transmitting an RRM measurement report to the base station, wherein the carrier is a carrier that does not include a control channel and the signal is a CRS, a CSI-RS, a TRS, a DM -RS, PSS, SSS, or a reference signal by upper layer signaling.

The base station measuring the RRM of the mobile communication network according to another embodiment of the present invention includes a transmitter for transmitting a message instructing RRM measurement of a carrier to a terminal and transmitting a signal necessary for RRM measurement of the carrier, A CRS, a CSI-RS, a TRS, a DM-RS, and a DM-RS; and a control unit that controls the transmission unit and the reception unit, wherein the carrier is a carrier that does not include a control channel, PSS, SSS, or a reference signal based on upper layer signaling.

1 shows a communication system to which embodiments of the present invention are applied.
FIG. 2 shows a control region in which a control channel including a PDCCH, a PCFICH, and a PHICH are transmitted in one subframe, and a data region in which a data channel including a PDSCH is transmitted.
3 is an ePDCCH implementation scheme to which one embodiment of the present disclosure is applied.
4 shows the distributed transmission and the centralized transmission of the ePDCCH.
FIG. 5 shows the positions of PSS / SSS on a symbol of OFDM in the case of FDD and TDD.
FIG. 6 shows the positions of PBCHs on OFDM symbols.
FIG. 7 shows positions of subcarriers (resource elements) of PSS / SSS, PBCH for the entire bands of 20 MHz, 10 MHz, 5 MHz, 3 MHz and 1.4 MHz, respectively.
8 shows a symbol-based cyclic shifted eREG indexing for a PRB pair for a PRB pair when CRS port 0 is set when EPDCCH is used as an NCT structure.
Figure 9 shows the collision of PSS / SSS and DM-RS.
FIG. 10 illustrates code divisional multiplexing of PSS / SSS and DM-RS according to an embodiment of the present invention.
11 is a diagram illustrating a procedure in which a base station instructs a UE to perform RRM measurement for RRM measurement in a carrier, which is an NCT according to an embodiment of the present invention.
FIG. 12 is a diagram illustrating a procedure in which a mobile station performs RRM measurement and transmits an RRM measurement report to a base station for RRM measurement in a carrier, which is an NCT according to an embodiment of the present invention.
Figure 13 shows intra-frequency RRM measurements with 2 ms on duration and 40 ms DRX periods in two neighboring NCT cells with a 5 ms TRS transmission period.
FIG. 14 is a diagram illustrating a process of performing RRM measurement between a base station and a terminal in a mobile communication network according to an embodiment of the present invention.
15 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.
16 is a 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 symbols as 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.

1 shows a communication system to which embodiments of the present invention are applied.

Communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

1, a communication system includes a user equipment (UE) 10 and a transmission point 20 for performing uplink and downlink communication with the terminal 10. [

The terminal 10 or user equipment (UE) in the present specification is a comprehensive concept of a user terminal in wireless communication. The terminal 10 or UE is a mobile terminal in the GSM, a mobile station (MS) in UT, User Terminal, SS (Subscriber Station), wireless device, and the like.

A transmission terminal 20 or a cell generally refers to a station that communicates with the terminal 10 and includes a base station, a Node-B, an evolved Node-B (eNB), a base transceiver station (BTS) System, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and the like.

In this specification, a transmission terminal 20 or a cell should be interpreted in a generic sense to indicate a partial area covered by a BSC (Base Station Controller) in a CDMA, a NodeB of a WCDMA, etc., and a RRH Which means any type of device capable of communicating with one terminal, such as a cell, a cell, a head, a relay node, a sector of a macro cell, a site, a microcell such as another femtocell, Used as a concept.

Herein, the terminal 10 and the transmission terminal 20 are used in a broad sense as a transmitting / receiving entity used to implement the technical or technical idea described in the present specification and are not limited to a specific term or word.

Although one terminal 10 and one transmission terminal 20 are shown in Fig. 1, the present invention is not limited thereto. One transmission terminal 20 can communicate with a plurality of terminals 10 and one terminal 10 can communicate with a plurality of transmission terminals 20. [

There is no limitation on a multiple access technique applied to a communication system, and the present invention is applicable to a CDMA (Code Division Multiple Access), a TDMA (Time Division Multiple Access), an FDMA (Frequency Division Multiple Access), an OFDMA (Orthogonal Frequency Division Multiple Access) -FDMA, OFDM-TDMA, and OFDM-CDMA.

In addition, the present invention can be applied to a TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, a Frequency Division Duplex (FDD) scheme in which different frequencies are used, It is applicable to the hybrid duplexing method.

In particular, embodiments of the present invention provide asynchronous wireless communications that evolve into LTE (Long Term Evolution) and LTE-Advanced (LTE-A) over GSM, WCDMA, and HSPA and synchronous wireless communications that evolve into CDMA, CDMA- Wireless communication field, and the like. It should be understood that the present invention is not limited to or limited to a particular wireless communication field and should be construed as including all technical fields to which the spirit of the present invention may be applied.

Referring to FIG. 1, a terminal 10 and a transmission terminal 20 can perform uplink and downlink communications.

The transmission terminal 20 performs downlink transmission to the terminal 10. The transmission unit 20 may transmit a Physical Downlink Shared Channel (PDSCH), which is a primary physical channel for unicast transmission. In addition, the transmission terminal 20 transmits scheduling approval information for transmission on the uplink data channel (for example, a physical uplink shared channel (PUSCH)), downlink control information such as scheduling required for PDSCH reception, A Physical Downlink Control Channel (PDCCH) for transmitting information, a Physical Control Format Indicator Channel (PCFICH) for transmitting an indicator for distinguishing between PDSCH and PDCCH regions, an uplink transmission And a physical HARQ indicator channel (PHICH) for transmission of HARQ (Hybrid Automatic Repeat reQuest) acknowledgment to the BS. Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

The transmission terminal 20 transmits a cell-specific reference signal (CRS), a MBSFN reference signal (MBSFN-RS), a UE-specific reference signal (DM-RS), a position reference signal (PRS), and a CSI reference signal (CSI-RS).

Meanwhile, one radioframe or radio frame is composed of 10 subframes, and one subframe is composed of two slots. The radio frame has a length of 10 ms and the subframe has a length of 1.0 ms. In general, a basic unit of data transmission is a subframe unit, and downlink or uplink scheduling is performed in units of subframes.

One slot may have a plurality of OFDM symbols in the time domain and at least one subcarrier in the frequency domain. For example, the slot may include 7 OFDM symbols in the time domain (in case of Normal Cyclic Prefix) or 6 (in case of Extended Cyclic Prefix) and 12 subcarriers in the frequency domain. The time-frequency domain defined by one slot may be referred to as a resource block (RB), but is not limited thereto.

2 shows a control region 201 in which a control channel including a PDCCH, a PCFICH, and a PHICH are transmitted in one subframe, and a data region 202 in which a data channel including a PDSCH is transmitted. In Fig. 2, the horizontal axis represents time and the vertical axis represents frequency. FIG. 2 shows one sub-frame (1 ms) on the time axis and one channel (for example 1.4, 3, 5, 10, 15, or 20 MHz) on the frequency axis.

The PCFICH consists of 2 bits of information corresponding to the OFDM symbol, which is the size of the control area 201, and is encoded into a 32-bit code word. The encoded bits are scrambled using cell-specific and sub-frame-specific scrambling codes to randomize intercell interference and then modulated with Quadrature Phase Shift Keying (QPSK) to form 16 resource elements Lt; / RTI > The PCFICH is always mapped to the first OFDM symbol of each subframe. When the PCFICH is mapped to the first ODFM symbol of the subframe, it is divided into four groups, and the groups are well separated and mapped in the frequency domain to obtain excellent diversity as a whole.

The PDCCH (control information) is used to transmit downlink control information (DCI) such as scheduling decisions and power control commands. As an example, in LTE / LTE-A, DCI format 0 and DCI format 4 are used for uplink grant. The DCI format 1 / 1A / 1B / 1C / 1D / 2 / 2A / 2B / 2C is used for downlink scheduling assignment. And DCI format 3 / 3A is used for power control.

Each DCI message payload is accompanied by a cyclic redundancy check (CRC), and an RNTI (Radio Network Temporary Identifier) for identifying the UE is included in the CRC calculation process. After appending the CRC, the bits are encoded into a tail-biting convolutional code, and are matched to the amount of resources used for PDCCH transmission through rate matching.

The PDCCH may be transmitted in a common search space or a UE specific search space of the control domain 201. [ Each terminal 10 searches for a PDCCH through blind decoding in a common search space commonly allocated to UEs in a cell and in a UE-specific search space assigned to itself, and upon confirming PDCCH reception, It is possible to perform control based on the control information transmitted through the network.

Meanwhile, the LTE / LTE-A system defines the use of a plurality of unit carriers (Component Carriers) as a scheme for expanding the bandwidth to satisfy the system requirements, that is, a high data rate. In this case, one CC can have a maximum bandwidth of 20 MHz, and resources can be allocated within 20 MHz according to the corresponding service. However, this is only one example according to the process of implementing the system. .

In order to increase the data transmission speed, technologies such as a Multiple Input / Multiple Output (MIMO), a Coordinated Multiple Point (CoMP), and a relay node have been proposed. It is necessary to transmit more control information in the same transmission terminal as the base station.

However, when the size of the control region in which the PDCCH is transmitted is limited, a method of increasing the transmission capacity of the PDCCH can be considered as a method of transmitting control information to be transmitted through the PDCCH in the data area in which the PDSCH is transmitted. This method can support a large PDCCH capacity without reducing the reception reliability of the PDCCH. Control information corresponding to a PDCCH transmitted in a data region, for example, a PDSCH region, may be referred to as extended control information (Extended PDCCH, ePDCCH, X-PDCCH) or PDCCH-A (PDCCH-Advanced) Hereinafter, ePDCCH will be collectively described. The ePDCCH is also used for the R-PDCCH, which is the control channel for the relay. That is, the ePDCCH is a concept including both a control channel for relay and a control channel for inter-cell interference control. According to an embodiment of the present invention, the ePDCCH can be allocated to a data area (data channel area) of an arbitrary subframe.

The above-described ePDCCH is a new type of PDCCH considered in the Rel-11 LTE system, and it is necessary to allocate uplink control information (i.e., PUCCH) that can be caused by introducing the new PDCCH.

3 is an ePDCCH implementation scheme to which one embodiment of the present disclosure is applied.

The legacy PDCCH for the existing Rel-8/9/10 UE is transmitted to the legacy PDCCH region and the upper layer signaling or the SI information is transmitted from the Rel-11 UE to the legacy PDCCH region. A mode in which blind decoding is performed for only the e-PDCCH region (E-PDCCH region) can be considered.

According to the present embodiments, a new type carrier (NTC), Coordinated Multipoint Transmission / Reception (CoMP), and a downlink MIMO (Multi-input) are used in Carrier Aggregation (CA) in 3GPP LTE / EPDCCH for multi-output can be allocated to a PDSCH (Physical Downlink Shared Channel) which is a data area.

In this specification, allocation of control information is used in the same sense as allocation of a control channel. In other words, the allocation of control channels in this specification means allocating control information to resource elements.

At this time, the control channel is allocated in units of PRB (Physical Resource Block) pairs corresponding to two slots, i.e., one subframe, and PDSCH and ePDCCH can not be simultaneously allocated to one PRB pair. In other words, PDSCH and ePDCCH can not be multiplexed in one PRB pair.

Meanwhile, control information or control channels of two or more UEs may be allocated to two or more PRB pairs or may be allocated in one PRB pair to multiplex control information of UEs.

4 shows the distributed transmission and the centralized transmission of the ePDCCH.

Referring to FIG. 4, when multiplexing the control information of the UEs, one eCCE may be allocated to two or more PRB pairs in a distributed manner or localized in one PRB pair. The former case is referred to as a distributed transmission or distributed type (410 in FIG. 4), and the latter case is referred to as a centralized transmission or centralized type (420 in FIG. 4).

Localized transmission improves performance in low-speed movement. Distributed transmission increases control information in the control area during high-speed movement. Performance is improved over the transmitted PDCCH.

Meanwhile, it may support a common search space (CSS) in connection with a search space. RNTI, P-RNTI, RA-RNTI, TPC-PUCCH-RNTI, and TPC-PUSCH-RNTI, which can transmit a common RNTI (Common RNTI).

According to the trend of standardization of 3GPP LTE-Advanced, various discussions about carriers are proceeding. One of them is a new type of carrier (NCT).

The NCT is a primary CC of a component carrier (CC) (hereinafter referred to as "CC") merged through a carrier aggregation (CA) Refers to a sub CC that reduces overhead to increase the payload size in a secondary CC, that is, an element carrier that does not include a control region.

These NCTs are divided into Standalone NCT (S-NCT) and Non-standalone NCT (NS-NCT) types. Non-standalone NCT (NS-NCT) In the NCT, a Physical Downlink Control Channel (PDCCH), a Physical HARQ Indicator Channel (PHICH), a Physical Control Format Indicator Channel (PCFICH), and a Cell-Specific Reference Signal (CRS) ) Will not be transmitted.

The transmission terminal 20 transmits a cell-specific reference signal (CRS), a MBSFN reference signal (MBSFN-RS), a terminal-specific reference signal (DM-RS), a Positioning Reference Signal (PRS), and a CSI-reference signal (CSI-RS).

The transmission terminal 20 transmits a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for synchronization with a base station and cell identification of a corresponding base station, (Hereinafter referred to as 'SSS') to at least one specific RB (Resource Block) in at least one subframe of one radio frame. At this time, the transmission terminal 20 has side effects such as interference with the user equipment (UE) (ICIC), conflict with setting of DM-RS (Demodulation Reference Signal, DMRS) The position of the PSS / SSS for the asynchronous NCT, which is one of the CCs not including the control region, can be changed on the time axis (symbol axis) as described below.

Meanwhile, the transmission terminal 20 will not transmit a cell-specific reference signal (CRS) in the downlink of the NCT. Instead, the transmitting end 20 may transmit a tracking reference signal (TRS). TRS can be regarded as a reduced CRS (CRS) which is transmitted in 5ms cycle based on the existing antenna port 0 and Rel.8 sequence of CRS. The transmission terminal 20 can also transmit a UE-Specific Reference Signal (DM-RS) and a CSI-RS (CSI-RS) signal in the NCT.

Therefore, since the CRS is not transmitted, the basic demodulation can be performed based on the DM-RS, so that the position of the PSS / SSS can be moved to another OFDM symbol in order to solve the collision problem between the PSS / SSS and the DM- have. The PBCH transmission pattern based on the DM-RS will be described in detail below.

FIG. 5 shows the positions of PSS / SSS on a symbol of OFDM in the case of FDD and TDD.

Referring to FIG. 5, in the case of FDD, the PSS is transmitted to the last symbol of the first slot of the subframes 0 and 5, and the SSS is transmitted to the second symbol at the end of the same slot.

In case of TDD, the PSS is transmitted in the third symbol (i.e., DwPTS) of subframes 1 and 6, and the SSS is transmitted in the last symbols of subframes 0 and 5.

FIG. 6 shows the positions of PBCHs on OFDM symbols.

Referring to FIG. 6, the PBCH is mapped to four subframes. The PBCH is mapped to the first four symbols of the second slot of subframe 0 of each radio frame in a normal CP and an extended CP.

FIG. 7 shows positions of subcarriers (resource elements) of PSS / SSS, PBCH for the entire bands of 20 MHz, 10 MHz, 5 MHz, 3 MHz and 1.4 MHz, respectively.

Referring to FIGS. 5 and 7, in the case of FDD, the PSS is matched to 72 subcarriers in the center of the entire band. Therefore, the PSS occupies 72 resource elements in the center except DC subcarriers in subframes 0 and 5. The SSS occupies 72 Resource Elements in the middle except the DC subcarriers in subframes 0 and 5.

In the case of TDD, the PSS occupies 72 resource elements in the center except DC subcarriers in subframes 1 and 6. In the same way as FDD, in the case of TDD, the SSS occupies 72 resource elements in the center excluding DC subcarriers in subframes 0 and 5.

Referring to FIGS. 6 and 7, the PBCH is transmitted over 72 subcarriers in the center of the entire band in the first four symbols of the second slot of subframe 0.

However, after the cell search process, the UE transmits a master information block (MIB), which is system information, through a physical broadcast channel (PBCH) in a control signal, and after the system information is received and decoded, the UE performs a random- To the cell.

FIG. 8 shows a symbol-based cyclic shifted eREG indexing for a PRB pair for a PRB pair when a CRS port (port) 0 is set when an EPDCCH is used as an NCT structure.

Even if another CRS port is set, a symbol-based cyclic shifted eREG indexing for a PRB pair may be performed as shown in FIG. 7 regardless of the RE position and number of CRSs.

As described above, NCT is divided into standalone NCT (S-NCT) and non-standalone NCT (NS-NCT) type, and non-standalone NCT (Synchronized carrier) NCT and an asynchronous carrier (unsynchronized carrier) NCT. When the NCT is aggregated with adjacent legacy carriers, the synchronization may be provided by an existing carrier. (When the new carrier type is aggregated with an adjacent legacy carrier, synchronization may be provided by the legacy carrier. In the case of aggregation with non-adjacent carriers and in the case of stand-alone operation, the NCT needs to provide an appropriate synchronous signal for discovery and time / frequency tracking (at least in the case of aggregate non-adjacent carriers and in stand- operation of the new carrier type needs to provide a proper synchronization signal for discovery and time / frequency tracking).

The following is summarized. The NCT is divided into a stand-alone NCT and a non-stand-up type NCT, and the non-stand-up type NCT is divided into a synchronous carrier NCT and an asynchronous carrier NCT. When the NCT is aggregated with non-adjacent carriers, the NCT needs to provide simultaneous signals for discovery or time / frequency tracking because the physical characteristics are different from other aggregated non-adjacent carriers. Also, in the case of a stand-alone NCT, it also has its own physical characteristics, so it is also necessary to provide simultaneous signals for discovery or time / frequency tracking. In this case it is necessary to provide an RRM measurement procedure for the NCT. First, the PSS / SSS is as follows.

1. Details of PSS / SSS (details)

However, since the CRS is not transmitted in the NCT, a problem may arise in reception and demodulation of a control channel such as a conventional PBCH based on CRS. However, the CRS may be transmitted at a cycle of 5 ms, or may be transmitted only in a specific frequency band, or the TRS may be transmitted in a combination of both.

Meanwhile, the PBCH is transmitted on the center 6PRB of the second slot of the subframe 0 of each radio frame.

A UE may not only access a system for the first time but also a plurality of elements merged through handover to support cell reselection and mobility and through Carrier Aggregation (CA) And carries out a cell access procedure even when it finds a synchronization for a carrier wave (hereinafter, referred to as 'CC').

The cell search process consists of PSS detection and SSS detection to obtain frequency and symbol synchronization for the cell, thereby obtaining frame / slot synchronization of the cell and determining the cell ID. On the other hand, the NCT may perform this process either in parallel with the PSS / SSS or via another signal.

If the cell synchronization is obtained and the cell ID is determined, a confirmation step of whether the corresponding cell is the NCT or the LCT is performed and the TRS is confirmed, thereby performing RRM measurement or PBCH channel demodulation. If the CRS is not transmitted as described above, PBCH channel demodulation is performed based on the DM-RS. The PBCH channel contains system information.

Therefore, PSS / SSS detection and PBCH detection are the basis for the cell access process according to the cell search.

In order to avoid collision between the PSS / SSS and the DM-RS, the position of the PSS / SSS can be moved on the time axis or DM-RS puncturing can be performed.

However, if a DM-RS is punctured, a channel estimation error may occur in a PBCH that estimates a channel based on a DM-RS, and this channel estimation error may be particularly serious for a UE moving at high speed. One way to solve this channel estimation error is to change the PBCH channel mapping position on the time axis.

In order to avoid collision with DM-RS when PSS / SSS is present in NCT, it is suggested to move to another OFDM symbol position, DM-RS puncturing, and examples of PBCH transmission pattern according to DM-RS pattern have. Specifically, there is a method of maintaining the relative position of the PSS / SSS and a method of changing the relative position of the PSS / SSS in order to move the PSS / SSS in order to avoid collision between the PSS / SSS and the DM-RS. On the other hand, there is a method for prohibiting PDSCH transmission from PRBs having PSS / SSS (for example, six PRBs around the center frequency) separately from DM-RS puncturing method. The DM-RS pattern (e.g. in all subframes) can be changed on the NCT to provide improved performance of PDSCH demodulation in the absence of the legacy control domain.

In order to avoid a collision with the DM-RS when there is a PSS / SSS in the NCT, the present invention determines whether to move to another OFDM symbol position, DM-RS puncturing, and a PBCH transmission pattern according to a DM- SSS and DM-RS, while maintaining the same position as the existing PSS / SSS and DM-RS.

Figure 9 shows the collision of PSS / SSS and DM-RS.

As shown in FIG. 9, an interference / collision problem between the PSS / SSS and the DM-RS occurs due to duplication of the same location / location. That is, the DM-RS shown in 910 of FIG. 9 and the PSS / SSS in the 0/5 subframe of 920 are allocated to the symbols on the same time axis. On the other hand, the positions of the PSS / There are suggestions for avoiding these problems. Of course, in another embodiment, it is also possible to consider transmitting a signal so that it can be discriminated instead of changing the position of the DM-RS.

Therefore, it is possible to avoid collision between PSS / SSS and DM-RS by code divisional multiplexing of PSS / SSS and DM-RS without changing the position of PSS / SSS or DM-RS in NCT present.

To support MU-MIMO as described in detail below, DM-RS is multiplexed using orthogonal sequences when mapping to complex demodulation symbols.

Antenna port (substantially the same applies to antenna port 5)

, The sequence r (m) of the DM-RS related to the PDSCH can be defined by the following equation (1).

[Equation 1]

In Equation (1)

May be 110 as the maximum downlink bandwidth in units of resource blocks (RBs). The pseudo-random sequence c (i) can be initialized as shown in Equation (2).

&Quot; (2) "

In Equation (2), n _s may have a value of 0 to 19 as a slot number. The _SCID is a scrambling identity and may have a value of 0 or 1.

The value of

Is not provided by the upper layer or DCI format 1A is used as the DCI.

), And in other cases

to be. According to

Equations

1 and 2, the DM-RS may have pseudo orthogonality when the values of n _SCID are different from each other.

Antenna port (substantially the same applies to antenna port 5)

, A part of the DM-RS in the PRB (Physical Resource Block) having the frequency domain index n _PRB

r (m) is mapped to the complex demodulation symbols of Equation (3) in a subframe according to a normal cyclic prefix (CP).

&Quot; (3) "

The symbol number l and the subcarrier number k of the resource element RE to which the sequence r (m) of the DM-RS related to the PDSCH is mapped can be determined as shown in Equation (4).

&Quot; (4) "

In Equation 4,

Is the resource block size in the frequency domain expressed by the number of subcarriers, n _PRB is the physical resource block number, and n _s is the slot number. In this case,

Can be given in Table 1 below.

[Table 1]

On the other hand, a part of the DM-RS

r (m) is mapped to the complex demodulation symbols of Equation (5) in a subframe according to an extended cyclic prefix (CP).

&Quot; (5) "

The symbol number l and the subcarrier number k of the resource element RE to which the sequence r (m) of the DM-RS related to the PDSCH is mapped can be determined according to Equation (6).

&Quot; (6) "

In this case,

Can be given in Table 2 below.

[Table 2]

The present invention can avoid collision between PSS / SSS and DM-RS by code divisional multiplexing of PSS / SSS and DM-RS without changing the position of PSS / SSS or DM-RS in NCT . For example, an orthogonal sequence may be further used when mapping the DM-RS to the complex demodulation symbols in the position duplication / collision of the PSS / SSS and the DM-RS.

FIG. 10 illustrates code divisional multiplexing of PSS / SSS and DM-RS according to an embodiment of the present invention. FIG. 10 is a diagram illustrating the orthogonality between the DM-RS signal and the PSS / SSS by applying the OCC of Table 1 to the DM-RS when the PSS / SSS and the DM-RS are mapped to the same symbols, Thereby eliminating interference. As a result, even if the DM-RS and the PSS / SSS are provided to the same symbol, the terminal can distinguish the DM-RS and the PSS / SSS.

9, since code division multiplexing is applied, interference between the DM-RS and the PSS / SSS located in the same symbol can be avoided.

Specifically, a part of DM-RS

r (m) is mapped to the complex demodulation symbols of Equation (7) in a subframe according to a normal cyclic prefix (CP).

&Quot; (7) "

In Equation (7), W (l) denotes w (x, y), x denotes the position of the symbol of the corresponding slot in the corresponding subframe, and y denotes the position of the subcarrier.

Therefore, if w (x, y) is w (5,0), w (6,0), w (5,1) W (5,10), w (6,10), w (5,10), w (6,5) , 11) and w (6, 11)

The additional orthogonal sequence, e.g., [1,1, -1, -1], is further multiplied by the complex demodulation symbols, so that the DM-RS can be code division multiplexed with the PSS / SSS.

The transmission end may transmit the orthogonal code used for the code division multiplexing of the DM-RS and the PSS / SSS to the mobile station implicitly or explicitly (RRC signaling or system information), but without transmitting the orthogonal code, Orthogonal codes may be sequentially blind decoded. In other words, as shown in FIG. 10, when DM-RS and PSS / SSS are code division multiplexed using 8 orthogonal codes, 8 orthogonal codes can be sequentially used for blind decoding.

2. RRM measurements for NCT (RRM measurements for NCT)

The function of the RRM measurement for the NCT is not for mobility (handover or cell (re-selection), but rather determines the addition or removal of the NCT with SCell based on the RRM measurement reports by the terminal, . The addition or removal of the NCT may use the RRCConnectionReconfiguration message. RRM measurements for NCT can only be applied to RRC connected terminals for inter-frequency as well as intra-frequency measurements. In other words, the RRM measurement for the idle mode is not necessary. RRM measurements can be applied to both synchronous NCT and asynchronous NCT. Like CA, reference signal received power (RSRP) and reference signal received quality (RSRQ) matrices can be defined for NCT RRM measurements. Table 3 shows RSRP and RSRQ. RSRP denotes the reception power of the received reference signal RS, and RSRQ denotes the quality of the received reference signal. RRM measurement models and procedures defined for the CA for SCell addition / removal can be reused for the NCT.

[Table 3] RSRP and RSRQ

NCT does not transmit legacy CRS by definition. Therefore, another RS for RRM measurement for NCT needs to be used. RS transmissions on the NCT include CSI-RS, DM-RS and PSS / SSS. For frequency and time synchronization purposes, the NCT can carry 1RS ports (consisting of Rel-8 CRS Port 0 REs and Rel-8 sequences per PRB) in one subframe at 5ms intervals.

Of the signals transmitted on the NCT, only at least one of CSI-RS and TRS (or a combination thereof) can be considered as RSs for RRM measurement.

If the TRS is used for both synchronous and asynchronous carriers, the TRS can be used as an RS for RRM measurements. At this time, the same RRM measurement method can be applied to synchronous and asynchronous NCTs. In order to select subframes among the TRS subframes for RRM measurement with periodic TRS transmission, the UE must know when the TRS is transmitted. For serving cell RRM measurements, the terminal must obtain system information such as the cell type (e.g., Legacy Cell Type (LCT) or NCT) and the subframe offset of the TRS subframes (if configured). For intra-frequency RRM measurement, information of TRS sub-frames of neighboring cells can not always be known to the UE. Meanwhile, if the UE is configured to have a measurement object, the measurement request may include the cell type of the target cell or the information of the TRS.

Figure 13 shows intra-frequency RRM measurements with 2 ms on duration and 40 ms DRX periods in two neighboring NCT cells with a 5 ms TRS transmission period.

As shown in FIG. 13, assume an intra-frequency RRM measurement with 2 ms on duration and 40 ms DRX period in two neighboring NCT cells with a 5 ms TRS transmission period. As shown in the left circle of FIG. 13, since there is no TRS transmitted during the activation time of the DRX cycle, the UE can not perform the RSRP measurement of the NCT carrier in the DRX cycle. Therefore, in this case, DRX activation time (on duration) can be set not less than 5 ms so that at least one TRS can be transmitted during the activation time.

On the other hand, RRM measurements based on multiple CSI-RS resources for one NCT cell in a CSI-RS based RRM measurement can be considered to increase measurement accuracy.

Meanwhile, when the TRS is transmitted, the TRS-based RRM measurement is performed, and when the TRS is not transmitted, the CSI-RS based RRM measurement can be performed. For example, in the case of a synchronous NCT, synchronization information is delivered from a legacy carrier. Therefore, the transmission of PSS / SSS / TRS may not be performed on the synchronization carrier. In this case, a CSI-RS based RRM measurement may be used.

3. Synchronized new carriers (NCTs)

Synchronized new carriers may be limited to the case of intra-band contiguous carrier aggregation (CA) in a band using a single RF front end. The CRS can be transmitted for RRM measurement purposes regardless of time / frequency tracking. On the other hand, PSS / SSS can be eliminated.

On the other hand, RSs for time / frequency synchronization and tracking of the synchronous NCT can be signaled (transmitted / forwarded) to the terminal by higher layer signaling. In this case, the PSS / SSS / CRS / TRSs may not be transmitted for the synchronization NCT.

The segment may be in the same band as the backward compatible carrier (BCC) only for the downlink. At this time, the segment size may be equal to or less than BCC. The BCC and segment can be time / frequency synchronized. PSS / SSS / PBCH / SIBs are not sent to the segment. The single (E) PDCCH DCI indicates the BCC and the segment. One BCC and one HARQ for the segment may be used. The maximum resource allocation size of the BCC and the segment may be 110 PRB pairs (20 MHz). The segment may only support a unicast PDSCH. CRS can be sent on segments and TM1-10 can be supported. There can be a guard band between the BCC and the segment. The segment may be at one edge or both edges of the BCC.

MeasuredConfig, which is an information element, can be provided to the UE in an embodiment of the message transmitted by the base station to instruct the UE to measure RRM. Table 4 shows the structure of MeasConfig. Table 4 shows a configuration of an information element for indicating RRM measurement of an NCT carrier according to an embodiment of the present invention.

[Table 4] Configuration of MeasConfig

The UE can transmit an RRM measurement report to the base station, and the configuration of the RRM measurement report is shown in Table 5.

[Table 5] Configuration of MeasurementReport

11 is a diagram illustrating a procedure in which a base station instructs a terminal to perform RRM measurement for RRM measurement in a carrier, which is an NCT, according to an embodiment of the present invention.

Here, the carrier, which is the NCT, means a carrier that does not include a control channel.

The base station confirms the type of the carrier to perform the RRM measurement in order to instruct RRM measurement of the terminal (S1110). If the corresponding carrier is NCT, a message instructing the RRM measurement of the carrier, which is the NCT, is transmitted (S1130). The base station transmits a signal required for RRM measurement of the carrier (S1140), and receives the RRM measurement report from the terminal that received the signal (S1150). RRM measurement is performed in a legacy manner for carriers other than NCT (S1160). Although not shown in the figure, after performing the RRM measurement in the case of the NCT, the base station can decide to add or remove the NCT of the corresponding terminal. The addition or removal of NCT can use RRCConnectionReconfiguration as described above. The signals used for the RRM measurement may be CRS, CSI-RS, TRS, DM-RS, PSS, SSS, or a reference signal based on upper layer signaling.

The steps will be described in more detail as follows.

NCT is not a legacy scheme and can be divided into two cases: no CRS transmission and CRS transmission.

If CRS is not transmitted, it is necessary to transmit a new RS. To this end, CSI-RS, DM-RS, PSS / SSS and TRS are transmitted and RRM measurement can be performed using the same.

First, TRS is applicable to both synchronous and asynchronous NCTs. However, if the RRM measurement report is measured using the TRS, the base station may transmit the TRS transmission time to the terminal before receiving the RRM measurement report or in a message instructing the RRM measurement, And information on the TRS subframe of the neighboring cell may also be included for frequency-to-frequency RRM measurement. The offset information of the subframe in which the TRS is transmitted, the information of the TRS, or the type of the carrier. Meanwhile, as shown in FIG. 13, when the RRM measurement is performed using the TRS, the DRX activation time or the TRS transmission time can be adjusted so that the TRS is transmitted at the DRX activation time.

When using CSI-RS, PSS / SSS can be eliminated and multiple CSI-RS resources can be used to increase the accuracy of RRM measurement using CSI-RS. That is, when using CSI-RS, the NCT carrier may be a synchronization carrier or may use multiple CSI-RS resources for a cell of the carrier.

CRS can only be sent with RRM measurements, regardless of time / frequency tracking. In another embodiment, a Reduced CRS may be transmitted. For example, a CRS is transmitted with a period of 5 ms, and RRM measurement can be performed using the CRS. This can be transmitted in a manner similar to TRS.

In case of a synchronized NCT, the terminal acquires via the associated legacy carrier for the synchronization information of the NCT. That is, the synchronization information of the synchronization carrier associated with the legacy carrier can be identified by the UE in the legacy carrier, and thus can remove the TRS / PSS / SSS signal. Accordingly, when the information is removed, the BS may transmit a CRS for the RRM measurement or the BS may transmit a reference signal using higher layer signaling.

In case of asynchronous NCT, PSS / SSS is transmitted, and RRM measurement can be performed using it. However, since the PSS / SSS is transmitted only in six central resource blocks (RBs), RRM measurement can be performed in combination with other signals, for example, CSI-RS, TRS, and the like.

12 is a diagram illustrating a procedure in which a mobile station performs RRM measurement and transmits an RRM measurement report to a base station for RRM measurement in a carrier, which is an NCT according to an embodiment of the present invention. Here, the carrier, which is the NCT, means a carrier that does not include a control channel.

12, the terminal receives a message indicating an RRM measurement of a carrier, which is an NCT, from the base station (S1210). Then, a signal necessary for RRM measurement of the carrier is received (S1220). Thereafter, the RRM measurement of the carrier is performed using the received signal (S1230), and the RRM measurement report is transmitted to the base station (S1240). In this case, the signals that can be used for measuring the RRM of the carrier having the NCT can be CRS, CSI-RS, TRS, DM-RS, PSS, SSS or a reference signal by upper layer signaling.

After the terminal transmits the RRM measurement report to the base station, the base station can instruct to add or remove the carrier, and the terminal can add or remove the carrier accordingly.

The steps will be described in more detail as follows.

In the case of NCT, the RRM measurement can be divided into the case of using CRS and the case of not using CRS. When the CRS is not transmitted from the NCT, RRM measurement is performed using the CSI-RS, the DM-RS, the PSS / SSS, and the TRS as described in FIG. That is, when the UE performs the RRM measurement using the TRS, it receives the offset information of the subframe in which the TRS is transmitted from the base station, the TRS information, or the type of the carrier. Further, the CSI-RS performs the RRM measurement, and the carrier can be a synchronization carrier or use multiple CSI-RS resources for a cell of the carrier.

Meanwhile, when the NCT is a synchronized NCT, the UE may receive a CRS for the RRM measurement or a reference signal using upper layer signaling from a base station.

FIG. 14 is a diagram illustrating a process of performing RRM measurement between a base station and a terminal in a mobile communication network according to an embodiment of the present invention. The user terminal 1401 and the base station 1402 or the EUTRAN exist and the base station 1402 transmits an RRM measurement indication message to the terminal 1401 in operation S1410. In addition, the base station 1402 transmits a signal necessary for RRM measurement (S1420). RS, TRS, DM-RS, PSS, SSS, or reference by upper layer signaling for the RRM measurement of the carrier if the carrier performing the RRM measurement is a control region, Signal or the like may be transmitted. Thereafter, the terminal 1401 performs RRM measurement using the received signals (S1430). The RRM measurement values calculated at this time may be RSRP, RSRQ, and the like, and include the MeasurementReport shown in Table 5 above. Table 6 shows a part of the configuration of MeasResult of MeasurementReport in Table 5.

[Table 6] Configuration of MeasResult

The terminal 1401 transmits the RRM measurement result to the base station 1402 (S1440)

The RRM measurement process in the carrier having the above-mentioned NCT has been described and the base station and the terminal described below can perform the RRM measurement method described above.

15 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.

Referring to FIG. 15, a base station 1500 according to another embodiment includes a control unit 1510, a transmission unit 1520, and a reception unit 1530.

The controller 1510 controls the overall operation of the base station according to the operation required for the RRM measurement of the carrier, which is the NCT, necessary for carrying out the present invention described above.

The transmitting unit 1520 and the receiving unit 1530 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

The base station of Fig. 15 performs the operations of Figs. 11 and 14 described above. The transmitting unit 1520 transmits a message for instructing RRM measurement of the carrier to the UE, and transmits a signal necessary for RRM measurement of the carrier. The reception unit 1530 receives the RRM measurement report from the terminal and the control unit 1510 controls the transmission unit 1520 and the reception unit 1530. If the carrier does not include a control channel, the control unit 1510 transmits a reference signal by CRS, CSI-RS, TRS, DM-RS, PSS, SSS, And the like can be transmitted.

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

16, a user terminal 1600 according to another embodiment includes a receiving unit 1630, a control unit 1610, and a transmitting unit 1620.

The receiver 1630 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, the controller 1610 controls the overall operation of the terminal, which is necessary for the RRM measurement of the carrier, which is the NCT, in performing the above-described present invention.

The transmitter 1620 transmits downlink control information, data, and messages to the base station through the corresponding channel.

The terminal 1600 in FIG. 16 performs the RRM measurement of the NCT carrier and transmits the result to the base station, which process is shown in FIGS. 12 and 14 above.

The receiver receives a message from the base station indicating the RRM measurement of the carrier and also receives a signal necessary for RRM measurement of the carrier. If the carrier does not include a control channel, the control unit 1610 determines whether the carrier is a reference by CRS, CSI-RS, TRS, DM-RS, PSS, SSS, RRM measurement is performed using a signal or the like.

The controller 1610 performs RRM measurement of the carrier using the received signal and controls the transmitter 1620 to transmit the RRM measurement report to the BS.

An embodiment has been described in which various signals are used to perform RRM measurement in a control channel, that is, a carrier in which a control region is not transmitted, called a so-called NCT. When the RRM is measured for the NCT carrier as described above, the base station can instruct the terminal to add or remove the carrier using the measured result. Implementation of the present invention overcomes the limitations of the RRM measurement due to the absence of a control channel in the NCT.

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 falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims

A method for measuring RRM of a mobile communication network,
Transmitting, by the base station, a message instructing measurement of a radio resource management (RRM) of a carrier to the mobile station;
Transmitting a signal necessary for RRM measurement of the carrier; And
And receiving the RRM measurement report from the terminal,
The carrier is a carrier that does not include a control channel, and the signal is a carrier-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a tracking reference signal (TRS), a demodulation reference signal (DM- , A Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), or a Reference Signal by a higher layer signaling.

The method according to claim 1,
Wherein the base station comprises determining to add or remove the carrier in accordance with the report.

The method according to claim 1,
If the RRM measurement report is measured using TRS,
Further comprising transmitting at least one of offset information of the subframe in which the TRS is transmitted, information of the TRS, or a type of the carrier before the step of receiving the RRM measurement report.

The method according to claim 1,
If the RRM measurement report is measured using CSI-RS,
Wherein the carrier is a synchronization carrier or uses multiple CSI-RS resources for a cell of the carrier.

The method according to claim 1,
If the carrier is synchronized with another carrier,
Wherein the base station transmits a CRS for the RRM measurement or the base station transmits a reference signal using higher layer signaling.

A method for measuring an RRM of a mobile communication network,
The method comprising: receiving a message from a base station indicating a Radio Resource Management (RRM) measurement of a carrier;
Receiving a signal necessary for RRM measurement of the carrier; And
Performing an RRM measurement of the carrier using the received signal and transmitting an RRM measurement report to the base station
The carrier is a carrier that does not include a control channel, and the signal is a carrier-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a tracking reference signal (TRS), a demodulation reference signal (DM- , A Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), or a Reference Signal by a higher layer signaling.

The method according to claim 6,
Wherein the terminal comprises receiving a message from the base station instructing to add or remove the carrier.

The method according to claim 6,
The UE performs the RRM measurement using the TRS,
Receiving at least one of offset information of the subframe in which the TRS is transmitted, information of the TRS, or the type of the carrier from the base station.

The method according to claim 6,
The UE performs the RRM measurement using the CSI-RS,
Wherein the carrier is a synchronization carrier or uses multiple CSI-RS resources for a cell of the carrier.

The method according to claim 6,
If the carrier is synchronized with another carrier,
Wherein the terminal receives the CRS for the RRM measurement from the base station or receives a reference signal using upper layer signaling.

A base station for measuring RRM of a mobile communication network,
A transmitter for transmitting a message indicating a measurement of a radio resource management (RRM) of a carrier to a terminal and transmitting a signal necessary for RRM measurement of the carrier;
A receiving unit for receiving the RRM measurement report from the terminal; And
And a control unit for controlling the transmitting unit and the receiving unit,
The carrier is a carrier that does not include a control channel, and the control unit determines that the signal is a carrier-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a tracking reference signal (TRS) Wherein the control unit controls the transmission unit to be at least one of a reference signal, a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a reference signal based on upper layer signaling.