WO2013100587A1

WO2013100587A1 - Resource mapping method of base station and e-pdcch reception method of terminal in wireless communication system, base station thereof, and terminal thereof

Info

Publication number: WO2013100587A1
Application number: PCT/KR2012/011500
Authority: WO
Inventors: 박경민
Original assignee: 주식회사 팬택
Priority date: 2011-12-30
Filing date: 2012-12-26
Publication date: 2013-07-04
Also published as: KR20130078406A

Abstract

The present invention provides a resource mapping method of a base station, an E-PDCCH transmission and reception method, and a device therefor, the resource mapping method including the steps of: determining a demodulation reference signal (DM-RS) port according to a transmission method and a set level, which are used in extended PDCCH (E-PDCCH) transmission, with respect to each of data regions usable for E-PDCCH transmission; and mapping an E-PDCCH and a DM-RS to the determined DM-RS port.

Description

Resource mapping method of base station and E-PCCCH reception method of terminal in wireless communication system, base station, terminal thereof

The present specification provides a mapping method of E-PDCCH and DM-RS and an apparatus for implementing the same.

Various techniques are being considered to increase the data transmission speed in a wireless communication system. For example, technologies such as Multiple Input Multiple Output (MIMO), Carrier Aggregation (CA), Coordinated Multiple Point (CoMP), and Wireless Relay Node improve data transmission speed. Is being considered for. In order to use these techniques, it may be necessary for the transmitting end to transmit more control information to the terminal.

Currently, in order to enable more control information to be transmitted, a method of transmitting control information to a radio resource through which data, rather than control information, is transmitted has been proposed.

The mapping method of the E-PDCCH and the DM-RS according to an embodiment of the present invention and an apparatus for implementing the same may support the E-PDCCH multiplexing more smoothly without increasing the blind detection complexity of the E-PDCCH.

According to an aspect, the present invention provides a DM-RS port (Demodulation Reference Signal Port) according to a transmission scheme and aggregation level used for E-PDCCH transmission for each data area available for E-PDCCH (Extended PDCCH) transmission. It provides a resource mapping method of the base station comprising the step of determining and mapping the E-PDCCH and DM-RS to the determined DM-RS port.

According to another aspect, the present invention provides a DM-RS port (Demodulation Reference Signal) determined according to a transmission scheme and aggregation level used for E-PDCCH transmission for each data area available for E-PDCCH transmission from a base station. receiving a radio signal including an E-PDCCH mapped to a port) and a demodulation reference signal (DM-RS), and detecting the E-PDCCH using the DM-RS from the received radio signal. It provides an E-PDCCH receiving method of a terminal.

According to another aspect, the present invention provides a DM-RS port (Demodulation Reference Signal port) determined for each data region available for E-PDCCH (Extended PDCCH) transmission according to the transmission scheme and aggregation level used for E-PDCCH transmission. It provides a base station including a mapping unit for mapping the E-PDCCH and DM-RS and a transceiver for transmitting a radio signal including the E-PDCCH and the DM-RS.

According to another aspect, the present invention provides a DM-RS port (Demodulation Reference) determined for each data area available for E-PDCCH transmission from a base station according to a transmission scheme and aggregation level used for E-PDCCH transmission. A transceiver for receiving a radio signal including an E-PDCCH mapped to a signal port) and a DM-RS (Demodulation Reference Signal) and a detection for detecting the E-PDCCH using the DM-RS from the received radio signal. It provides a terminal comprising a unit.

1 is a block diagram of a base station.

2 is a block diagram of the steps of DM-RS transmission and reception required for PDSCH transmission.

3 is a conceptual diagram of a subframe.

4 is a diagram illustrating a process of allocating an E-PDCCH, transmitting the same, and blindly detecting the E-PDCCH.

FIG. 5 is a diagram illustrating distributed resource allocation and localized resource allocation, which are methods of allocating resources according to an embodiment of the present specification.

FIG. 6 is a diagram illustrating spatial division multiplexing during E-PDCCH multiplexing.

FIG. 7 illustrates Time Code Division Multiplexing (TCDM) during E-PDCCH multiplexing. It shows that E-PDCCH is mapped by code division to each E-PDCCH resource allocated region.

8 is a flowchart illustrating a resource mapping method of a base station according to an embodiment.

9 is a conceptual diagram of using different DM-RS resources according to an aggregation level and a transmission scheme.

FIG. 10 illustrates an example of assigning different DM-RS ports to an aggregation level and a transmission scheme to a plurality of UEs (example for AL = 1/2).

FIG. 11 illustrates an example of DM-RS resource allocation using different DM-RS resources according to a search space or an E-PDCCH region and an aggregation level.

FIG. 12 is a diagram illustrating a process performed between a base station and a terminal in order to implement the embodiments described with reference to FIG. 8.

FIG. 13 illustrates a process of blind detection of an E-PDCCH by a UE in a process between a base station and a terminal in order to implement the embodiments described with reference to FIG. 8.

FIG. 14 illustrates a configuration of an apparatus for transmitting a radio signal by mapping an E-PDCCH to a resource in combination with a base station or a base station according to another embodiment.

FIG. 15 is a diagram illustrating a configuration of an apparatus for receiving an E-PDCCH mapped wireless signal in combination with a terminal or a terminal according to another embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, the terms or words used in the specification and claims described below should not be construed as being limited to the ordinary or dictionary meanings, the inventors should use the concept of terms in order to explain their own invention in the best way. It should be interpreted as meanings and concepts corresponding to the technical idea of the present invention based on the principle that it can be properly defined.

In the current mobile communication systems such as 3GPP, Long Term Evolution (LTE), LTE-A (LTE Advanced), etc., it is a high-speed, high-capacity communication system that can transmit and receive various data such as video and wireless data beyond voice-oriented services. Not only is the development of technology capable of transmitting large amounts of data comparable to wired communication networks, but also the proper error detection method to improve system performance by minimizing the reduction of information loss and increasing system transmission efficiency has become an essential element. .

Meanwhile, a communication system using a multiple-input multiple-output antenna (hereinafter referred to as "MIMO") may be used at both the transmitting and receiving ends, and may be a single UE (SU) or multiple UEs. MUs share the same radio resource capacity and receive or transmit a signal to one base station or the like.

In a system using MIMO, it is necessary to process a channel state by using various reference signals or reference signals, and feed back the result to a transmission terminal (another device).

That is, when one terminal is assigned a plurality of downlink physical channels, the terminal can adaptively optimize the system by feeding back channel state information for each physical channel to the base station. Signals of Channel Status Information-Reference Signal (CSI-RS), Channel Quality Indicator (CQI), and Precoding Matrix Index (PMI) may be used, and the base station may provide such channel status information. Channels can be scheduled. In addition, a cell-specific reference signal (CRS) transmitted in the entire downlink subframe is also transmitted by the base station to the terminals in the cell. Meanwhile, a sounding reference signal (SRS) for checking the state of the channel of the terminal and a demodulation reference signal (DM-RS) for demodulation are also used. In more detail, the CSI-RS is transmitted by the base station, and the PMI and the CQI are information reported by the terminal.

The wireless communication system is widely deployed to provide various communication services such as voice and packet data, and the wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB) and a remote radio head (RRH). And a unit that assists in the behavior of the base station. A terminal in the present specification is a comprehensive concept of a terminal in a wireless communication, WCDMA and UE (User Equipment) in the LTE, HSPA, etc., as well as MS (Mobile Station), UT (User Terminal), SS (SS) in GSM It should be interpreted as a concept that includes both a subscriber station and a wireless device.

A base station or a cell generally refers to a station that communicates with a terminal, and includes a Node-B, an evolved Node-B, an Sector, a Site, and a BTS. It may be called other terms such as a transceiver system, an access point, a relay node, and an RRH.

That is, in the present specification, a base station or a cell should be interpreted in a comprehensive sense indicating some areas or functions covered by a base station controller (BSC) in CDMA, a NodeB in WCDMA, an eNB or a sector (site) in LTE, and the like. It is meant to encompass various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node communication range.

In the present specification, the terminal and the base station are two transmitting and receiving entities used in implementing the technology or the technical idea described in the present specification and are used in a comprehensive sense and are not limited by the terms or words specifically referred to. The terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) means a method for transmitting and receiving data to the base station by the terminal, the downlink (Downlink, DL, or downlink) means a method for transmitting and receiving data to the terminal by the base station Means.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques 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-TDMA, OFDM-CDMA Can be used.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

Meanwhile, in LTE, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. Uplink and downlink transmit control information through control channels such as Physical Downlink Control CHannel (PDCCH), Physical Control Format Indicator CHannel (PCFICH), Physical Hybrid ARQ Indicator CHannel (PHICH), and Physical Uplink Control CHannel (PUCCH). A data channel is configured such as PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel) and the like to transmit data.

In LTE-A, a standard based on a single carrier in LTE is discussed, and a combination of several bands having a band smaller than 20 MHz is discussed, while a component carrier band having a band of 20 MHz or more is being discussed. In LTE-A, multi-carrier aggregation (hereinafter referred to as 'CA') is basically discussed in consideration of backward compatibility based on LTE's basic specifications. Up to five component carriers are considered in the link. Of course, five component carriers can be increased or decreased according to the environment of the system, and the present invention is not limited thereto. Hereinafter, the CC set refers to a set of two or more CCs configured for use in a corresponding system.

In CA, uplink ACK / NACK (ACKnowledgement / Negative ACKnowledgement) transmission, channel quality indicator (CQI), and precoding matrix indicators (PMI) are considered among various considerations related to control channel design. , Which is referred to as " PMI ") and RI (Rank Indicator (hereinafter, referred to as " RI ")).

LTE-A is basically considering backward compatibility of 3GPP LTE Rel-8 for the configuration of CA. CQI / PMI / RI information determined as a standard in LTE Rel-8 is performed by various methods through a physical uplink control channel (PUCCH) and a physical uplink shared channel (PUSCH) which are uplink control channels.

A wireless communication system to which an embodiment of the present specification is applied may support uplink and / or downlink HARQ.

On the other hand, when the number of terminals in the base station increases, the control signal provided to the terminal increases, and also requires more resources to transmit the control signal. In an embodiment of increasing the number of terminals, the number of terminals is divided into a case where the number of terminals is gradually increased in a cell managed by the base station and a case where the number of terminals is increased by using various multiplexing methods. In the latter case, a coordinated multi-point transmission / reception system or a coordinated multi-antenna transmission system in which two or more transmitters cooperate to transmit a signal , A cooperative multi-cell communication system (hereinafter referred to as "cooperative multi-cell communication system" or "CoMP"). In particular, in such a multi-cell communication system, various types of micros such as femto cells, pico cells, relays, hot spots, etc., located within a cell radius of one macro base station Or it may be local base stations (Remote Radio Head, hereinafter referred to as RRH). A network composed of various types of base stations is called a heterogenous network (hereinafter referred to as Het-Net).

In case of LTE Rel-10 PDSCH transmission, precoder and channel estimation are performed through DM-RS reception, and PDSCH demodulation is performed according to the channel information. The base station transmits information necessary for DM-RS reception, that is, DM-RS port number and information about DM-RS sequence scrambling, through the PDCCH, and the terminal acquires the above information through PDCCH reception and uses the same. DM-RS reception and PDSCH demodulation are performed.

1 is a block diagram for transmission of a DM-RS of a base station.

Closed loop MIMO technique is used to increase the capacity of wireless communication. In a closed loop MIMO technique, a receiving end or a terminal (hereinafter, referred to as a 'terminal') transmits channel information measured through a reference signal to a transmitting end and a transmitting end or base station (hereinafter referred to as 'base station'). Selects an appropriate precoder 110 based on channel information and transmits information (stream 0, ..., stream K-1) using the precoder 110. In order to recover the terminal information, the terminal should grasp the information and channel information of the precoder used. In LTE Rel-10 and later systems, channel estimation and precoder information estimation are simultaneously performed by transmitting and receiving DM-RS (DM-RS 0, ..., DM-RS K-1).

2 is a block diagram for DM-RS reception required for PDSCH transmission.

The terminal determines (receives) a cell ID through system information broadcast (S210), and identifies (acquires) a DM-RS base sequence generated by the cell ID (S212). The UE receives the PDCCH with blind detection (S214), identifies the band where the DM-RS is received through the band information and other information used for 'PDSCH transmission of the received PDCCH (S216), and is required for receiving the DM-RS. Information (DM-RS ports, DM-RS scrambling use, DM-RS index, etc.) is identified (acquired) (S218). The terminal acquires the UE specific DM-RS sequence using the scrambling index and the DM-RS base sequence among the information required for receiving the DM-RS (S220). The UE performs DM-RS reception of a band where a DM-RS is received through band information used for PDSCH transmission (S222), and performs channel estimation by using a UE-specific DM-RS sequence and DM-RS ports ( S224). The terminal demodulates the PDSCH transmission information through the estimated channel information and the used precoder information (S226).

On the other hand, as shown in Figure 3 E-PDCCH and R-PDCCH (Relay) as a method of transmitting the control information using a radio resource shared with the PDSCH (radio resources that can be used for PDSCH transmission or other data channel transmission) -PDCCH) is present. These are all characterized in that they are transmitted in a PDSCH or a data region rather than a control region. The E-PDCCH or R-PDCCH may perform resource allocation and transmission on the basis of a control channel element (CCE) or a resource block (RB).

R-PDCCH and E-PDCCH are similar techniques in that they transmit control information in the PDSCH region. However, the R-PDCCH is transmitted in the channel between the base station and the relay (relay), the E-PDCCH is transmitted in the channel between the base station and the terminal. The channel between the base station and the relay to which the R-PDCCH is transmitted has a very high probability of line of sight, low frequency selectivity, and low propagation loss, that is, a propagation characteristic. Good channel is organized. On the other hand, the channel between the base station and the terminal on which the E-PDCCH is transmitted fluctuates in transmission loss due to various environmental factors, and also shows high frequency selectivity.

In order to improve the performance of MIMO, CoMP, Het-Net wireless communication system, the PDCCH existing in the existing control region can be newly defined and simply implemented, or a part of the data region including PDSCH can be used for control information. have. Thus, unlike the existing PDCCH configuration, a newly designed PDCCH for transmitting more PDCCHs is referred to as an extended PDCCH (E-PDCCH) hereinafter. In the present invention, the E-PDCCH transmits control information transmitted through the existing PDCCH or control information transmitted through another channel through the existing PDSCH region (or data region) or through a band allocated to each terminal. Used as a generic term for the delivery technique. The implementation manner of the E-PDCCH may vary, and the invention described herein is not limited to the implementation manner of a specific E-PDCCH.

4 is a diagram illustrating resource allocation of an E-PDCCH, a process of transmitting the same, and blind detection of the E-PDCCH at the receiving end.

The base station allocates a resource for transmitting the E-PDCCH (Resource Allocation) (S410). Then, the receiving end, for example, the terminal which is the receiving end is notified about the allocated resources (S420). In operation S430, the E-PDCCH is transmitted through an allocated resource.

In the case of E-PDCCH transmission and reception, since the E-PDCCH uses a radio resource shared with the PDSCH, each UE measures channel information through the DM-RS as in the case of PDSCH transmission and reception shown in FIG. Based on the E-PDCCH reception. In the case of E-PDCCH reception, channel information measurement through DM-RS must be preceded. Therefore, the DM-RS port (physical location and OCC) and scrambling information (scrambling index) used for E-PDCCH transmission are blinded through blind detection. The above information should be obtained through estimation or semi-static signaling such as RRC signaling.

The receiving end may check the E-PDCCH by performing blind detection in the allocated resource using the acquired information (S440).

FIG. 5 is a description of distributed resource allocation (distributed resource allocation or distributed mapping, distributed transmission) and localized resource allocation (localized resource allocation or local mapping, local transmission). FIG. 5 is a diagram illustrating resource allocation when control information, such as R-PDCCH or E-PDCCH, is included in a PDSCH region and transmitted. It also shows an example of allocating resources in RB as a basic unit.

As shown in FIG. 5, an E-PDCCH resource block (RB) is a resource block (RB) that may be used for E-PDCCH transmission, and some or all of the RBs may be used for E-PDCCH transmission. In 510, an E-PDCCH is transmitted through distributed resource blocks. 520 is a local resource allocation scheme in which the E-PDCCH is transmitted through adjacent resource blocks.

In an environment where DM-RS ports and scrambling for each terminal are required to be different, a local resource allocation scheme and a UE specific precoder may be selected. On the other hand, in an environment where DM-RS ports or scrambling for each terminal are required to be the same, a distributed resource allocation method using random precoding or non-precoding may be selected.

On the other hand, in the case of the E-PDCCH, E-PDCCH multiplexing for a plurality of terminals within the same frequency in order to maximize the control channel capacity can be supported in two ways.

In case of using UE-specific precoding, multiplexed E-PDCCHs are mapped to different ports, or DM-RSs used for transmission of each E-PDCCH have different scrambling indexes.

On the other hand, when random precoding is used or E-PDCCH is transmitted without precoding, i.e., when multiplexing (e.g. CDM) different from the spatial division method is used, each E Allow the PDCCH to be transmitted on the same port. That is, the E-PDCCH allows the DM-RS port and the scrambling index to be shared.

610 is an E-PDCCH region of

UE

0, 620 is an E-PDCCH region of

UE

1, and 630 is an E-PDCCH region of UE 2. 640 shows an example of mapping the E-PDCCH regions of UE 0, UE 1, and

UE

2, and 650 shows that the E-PDCCH regions of UE 0 and UE 1 are multiplexed by SDM (Spatial Division Multiplexing). . This can be applied when UE 0 and UE 1 can spatially partition by beamforming.

When the base station acquires accurate channel information for each band in which the E-PDCCH is transmitted, spatial division as shown in FIG. 6 is possible.

FIG. 7 illustrates Time Code Division Multiplexing (TCDM) during E-PDCCH multiplexing. It shows that E-PDCCH is mapped by code division to each E-PDCCH resource allocated region. FIG. 7 shows a wideband or wideband E-PDCCH transmission and TCDM for obtaining frequency diversity gain.

The base station delivers or predetermines the information on the region (E-PDCCH region) to be confirmed when receiving the E-PDCCH to the terminal through RRC signaling. Thereafter, information on the DM-RS to be used for E-PDCCH reception is separately transmitted or the DM-RS is received through blind detection. Specifically, the following three methods can be used.

1. The base station transmits information on the use of the DM-RS port and scrambling to be used when transmitting the E-PDCCH for each terminal to the RRC. Since the DM-RS port and scrambling are pre-selected for each UE, the flexibility of E-PDCCH multiplexing is reduced.

2. When transmitting E-PDCCH, it transmits information on DM-RS used for E-PDCCH transmission by transmitting a separate PDCCH together. Dynamic DM-RS allocation is possible, but separate PDCCH transmission and reception may be required, resulting in an increase in PDCCH payload and an increase in UE blind detection complexity.

3. Information about DM-RS is not transmitted separately. The terminal acquires information on the DM-RS port and scrambling through blind detection. This method supports dynamic DM-RS allocation without separate PDCCH transmission. Since the UE independently performs the DM-RS detection, a complexity problem and a detection reliability problem may occur.

Hereinafter, the present invention sets the DM-RS resource used by each UE differently according to the aggregation level and transmission scheme of the E-PDCCH received by the UE, thereby more smoothly without increasing blind detection complexity. A method and apparatus for supporting E-PDCCH multiplexing are provided.

Referring to FIG. 8, in the resource mapping method 800 of the base station according to an embodiment, mapping an extended PDCCH (E-PDCCH) to be transmitted to a UE to a resource in a data area (S810), and a coupling level of the E-PDCCH ( And mapping different demodulation reference signals (DM-RSs) to DM-RS ports according to at least one of an aggregation level or a transmission scheme (S820).

In the resource mapping method 800 of the base station according to an embodiment, steps S810 and S820 are conceptually separated and described, but may be performed as one step. At this time, for each data area available for E-PDCCH (Extended PDCCH) transmission before step S810 and step S820, DM-RS port (Demodulation Reference Signal port) according to the transmission method and aggregation level used for E-PDCCH transmission The method may further include determining (or setting). Here, DM-RS port determination may be to determine the index or DM-RS port number of the DM-RS port. Thereafter, the E-PDCCH and the DM-RS are mapped to the DM-RS port determined (or configured) in steps S810 and S810.

In this case, the E-PDCCH may be mapped to the same port as the previous DM-RS port. As described above with reference to FIG. 3, the resource of the data region may perform resource allocation and transmission using a CCE (Resource Channel Element) or a RB (Resource Block) as a basic unit. That is, the E-PDCCH to be transmitted to the UE is mapped to the radio resources shared with the PDSCH, and the DM-RS is assigned to the resource of the data area by using different DM-RS ports according to the coupling level or transmission scheme applied to the mapped E-PDCCH. Mapping the E-PDCCH to the same DM-RS port.

The base station divides the E-PDCCH region for the data region and provides information on the divided region to the terminal. Since the allocation of such an area may be maintained semi-persistent, information about the area may be provided to the terminal through higher layer signaling or system information provision.

Using the channel state information reported by the terminal, the base station determines the region to include the E-PDCCH to be transmitted to the terminal and multiplexing in the region. The E-PDCCH is mapped to the resource of the determined region. And, the information about the determined region and the transmission scheme can be provided to the terminal, which is transmitted through higher layer signaling, system information, or information on the corresponding region of the control region. It can be included in the control information. When included in the control information of the control region (Control region), this information may be transmitted with the E-PDCCH.

8 and 9, the base station maps the DM-RS to use different DM-RS resources according to an aggregation level, a transmission scheme, and the like used for E-PDCCH transmission. In other words, DM-RS is mapped using a DM-RS resource differently according to at least one of an aggregation level or a transmission scheme of an E-PDCCH to a resource of two or more regions.

In FIG. 9, a base station maps DM-RSs using different DM-RS resources according to an aggregation level and a transmission scheme. In other words, if aggregation level = 4, the base station uses different DM-RS resources according to one of local transmission or split transmission, even if the aggregation level used for E-PDCCH transmission is the same. DM-RS can be mapped

In this case, this mapping information may be higher layer signaling, for example, RRC signaling. When the DM-RS resources are mapped in the above manner, each UE can selectively use one of a plurality of DM-RS resources for the same band or subband, thereby allowing freedom of DM-RS resource allocation or E-PDCCH multiplexing. Increases the degree of freedom. The DM-RS resource may be at least one of a DM-RS port and a scrambling index.

FIG. 10 illustrates an example in which UEs 0 to 4 allocated with the same E-PDCCH region use different DM-RS resources according to an aggregation level and a transmission scheme. level = 1 or 2 only for localized transmissions, and only for the case where the same DM-RS sequence (same base sequence and same scrambling) is used for each aggregation level, but the present invention is distributed Applicable to all levels of coupling in transmission and distributed transmission.

Table 1 shows an example of configuring different antenna ports according to an aggregation level for each terminal.

Table 1

According to the resource mapping method 800 of the base station according to the embodiment described with reference to FIG. 8 and the case where the fixed DM-RS port is used for channel estimation (measurement) when the UE receives the E-PDCCH. Comparing the performance gain when allocating different DM-RS ports for each aggregation level and transmission scheme to the UE, the performance gains are as follows.

When the UE reports a CQI as shown in Table 2, the resource mapping method 800 of the base station according to the embodiment described with reference to FIG. 8 provides an E-PDCCH region with a best band at each UE as shown in Table 3 below. On the other hand, if the DM-RS port for each terminal is specified, an example of E-PDCCH region allocation when the DM-RS port for each terminal is fixed (UE 0,1: port 7, UE 2,3: port 8) As shown in Table 4, a bad band should be allocated to some terminals. This leads to a decrease in reception reliability of the E-PDCCH. Here, the best band and the bed band may be a case where the channel state value of the corresponding band is more than or less than the reference channel state value, respectively, or the channel state value of the corresponding band is more than or less than the reference channel state value, respectively. Can be defined for the case.

TABLE 2

TABLE 3

Table 4

In more detail, when the CQI is reported to the base station by the terminal as shown in Table 2, the base station attempts to allocate SB0 to UEs 0 and 1 and SB1 to UEs 2 and 3. Considering the DM-RS port that each UE presented in the example of Table 1 should measure when receiving the E-PDCCH for each aggregation level, as shown in Table 3, UE 1 and UE 2 are the aggregation level. E-PDCCH is received through 1 and UE 0 and UE 3 receive the E-PDCCH through aggregation level 2 to avoid collision between DM-RSs and transmit the optimal band to each UE. Can be assigned to

On the other hand, if each UE is fixed to one DM-RS port to use for channel estimation (measurement) when receiving the E-PDCCH, for example,

UE

0, 1 is port 7,

UE

2, 3 is port 8 If selected to use, as shown in Table 4, UE 0 and UE 4 receive the E-PDCCH through a band showing a lower channel quality rather than a band guaranteeing an optimal channel. Because UE 0's best band is SB0 or UE 1's best band, SB0 and UE 0 and UE 1 use the same DM-RS port 7, the band where UE 0 with small CQI guarantees optimal channel for SB 0. Instead of SB0, another band SB4 is selected. UE 3 also selects another band SB3 instead of SB1, which is a band that guarantees an optimal channel.

This reduces the reception reliability of the E-PDCCH and also increases the aggregation level of the E-PDCCH transmitted to UE 0 and UE 3. Comparing Table 3 and Table 4, in both cases, the E-PDCCH for UEs UE 0 and UE 3 must be transmitted through a high aggregation level. At this time, all of the transmission through the high coupling level for the UE UE 0 and UE 3 is to maintain the reception reliability of the E-PDCCH because the CQIs of the selected band for each UE 0 and UE 3 is low as shown in Table 4 This is because the coupling level needs to be increased.

However, in the case of Table 3, since all E-PDCCHs are transmitted through a band showing high channel quality, E-PDCCH reception is easier than in the case of Table 4 where E-PDCCHs for half of terminals are transmitted through a band of low channel quality. It can be seen.

As described above, according to the resource mapping method 800 of the base station according to the exemplary embodiment described with reference to FIG. 8, it has been described that each terminal allocates a different DM-RS port for each aggregation level and transmission method. If the E-PDCCH of each UE can be multiplexed using the optimal band according to one CQI, each UE shall fix one DM-RS port to use for channel estimation (measurement) when receiving the E-PDCCH, or Other DM-RS ports may be allocated for each aggregation level and transmission scheme, or one of them may be arbitrarily or dynamically selected.

For example, when the CQI, which is the channel quality, is reported to the base station by each terminal as shown in Table 5, Table 6 and examples of DM-RS port fixing for each terminal (UE 0,1: port 7, UE 2,3: port 8 As shown in Table 7, when the DM-RS port is fixed to one type and a different DM-RS port for each aggregation level and transmission method is assigned to each terminal, the same performance can be obtained.

Table 5

Table 6

TABLE 7

Because the optimal bands of

UEs

0 and 1 using the same DM-RS port are

SB

0 and 1, respectively, and the optimal bands of

UEs

2 and 3 are

SB

0 and 1, respectively, of UEs using the same DM-RS port. Since the optimal bands are different from each other, the same performance can be achieved even if one DM-RS port is fixed for channel estimation (measurement) or a different DM-RS port is assigned to each aggregation level and transmission method. do. Thus, in this case, one of the two may be selected or the base station may select one of them arbitrarily or dynamically (periodically or aperiodically, at certain times of time). Meanwhile, the base station may transmit the related information to the terminal as higher layer signaling or control information.

However, in the above-described situation, even if only the method of allocating different DM-RS ports for each aggregation level and transmission method is performed according to the resource mapping method of the base station according to the embodiment described with reference to FIG. 8. There is an advantage that can be flexibly multiplexed even in the situation as shown in Table 4 or in Tables 5 to 7.

Finally, the base station maps a PDSCH to be transmitted to the terminal in resources of two or more regions and other regions, and transmits a radio signal including information through the E-PDCCH, DM-RS, and PDSCH to the terminal.

Referring back to FIG. 8, as described above, the base station uses the DM-RS using different demodulation reference signal (DM-RS) resources for at least one of the two or more regions and other resources for the at least one region. Map it.

8 and 11, the base station uses different DM-RS resources according to a search space for receiving an E-PDCCH or an E-PDCCH. In this case, the base station may set / determine the DM-RS using DM-RS resources differently according to an aggregation level or transmission scheme of the E-PDCCH in resources of two or more regions, but the present invention is not limited thereto.

As shown in FIG. 11, UE 0 and UE 1 use different DM-RS resources according to an aggregation level, while UE 2 is the same as UE1 in an E-PDCCH region overlapping with the E-PDCCH region of UE0. DM-RS resource mapping may be used, and DM-RS resource mapping of UE0 may be used in an E-PDCCH region overlapping with the E-PDCCH region of UE1.

For example, UE2 uses the same DM-RS resource mapping as UE0 for some areas where the UE receives the E-PDCCH or some of the search spaces where the UE performs blind detection for E-PDCCH reception and for other parts the UE. The same DM-RS resource mapping as can be used. In this case, the DM-RS may be configured using DM-RS resources differently according to an aggregation level or transmission scheme of the E-PDCCH. Although FIG. 11 illustrates that only the UE2 receives the E-PDCCH or a part of the search spaces that perform blind detection for receiving the E-PDCCH, the DM-RS is configured using the DM-RS resources differently. Similarly, some of the regions for receiving the E-PDCCH or the search spaces for performing blind detection for receiving the E-PDCCH may be configured differently using the DM-RS resource.

As described above, since DM-RSs are mapped using different DM-RS resources according to the search space, E-PDCCH multiplexing can be more smoothly supported. In addition, when the E-PDCCH region used for each UE to receive the E-PDCCH is configured differently, greater scheduling flexibility can be obtained.

Referring to FIGS. 8 and 11, the base station uses different DM-RS resources according to an area for receiving an E-PDCCH or a search space for receiving an E-PDCCH, but also an aggregation level or transmission scheme of the E-PDCCH. According to the present invention, a method for configuring DM-RS using a DM-RS resource has been described, but the present invention is not limited thereto. For example, the base station configures the DM-RS using the same DM-RS resources regardless of the aggregation level or transmission scheme of the E-PDCCH, but searches for an area for receiving the E-PDCCH or for receiving the E-PDCCH. Depending on space, other DM-RS resources may be used.

The base station 1300 divides the E-PDCCH region (S1310). In operation S1320, information about the divided area is provided to the terminal 1301. FIG. Since the division of the region can be maintained semi-persistent, the information about the region can be provided to the terminal through higher layer signaling or system information provision.

Thereafter, the base station 1300 receives the report of the channel state of the terminal 1301 (S1330). This is used to determine which of the divided regions according to the channel state of the UE to include the E-PDCCH or how to implement the multiplexing of the E-PDCCH, the reporting of this channel state can be made selectively.

Using the channel state information reported by the terminal 1301, the base station 1300 determines an area to include the E-PDCCH to be transmitted to the terminal and multiplexing in the corresponding area (S1340). In operation S1350, the E-PDCCH is mapped to the resource of the determined region.

Next, the base station 1300 uses a different DM-RS resource according to at least one of a coupling level, a transmission scheme, and a search space as described with reference to FIG. 8 in an area to include an E-PDCCH to be transmitted to the UE. It may be mapped (S1355). And, the information on the determined area and the transmission method can be provided to the terminal (S1360), which is transmitted through higher layer signaling, system information (system information) method, or the information about the area control area ( It can be included in the control information of the control region). When included in the control information, this information may be transmitted with the E-PDCCH.

The base station 1300 transmits a radio signal including the mapped E-PDCCH (S1370), and the terminal 1301 performs blind detection in the determined area (S1380).

FIG. 13 illustrates a process of blind detection of an E-PDCCH by a UE in a process performed between a BS and a UE in order to implement the embodiments described with reference to FIG. 8.

Referring to FIG. 13, the base station 1400 allocates an E-PDCCH region to each terminal in a terminal specific or common manner (S1410).

Next, the base station 1400 allocates a DM-RS port and / or a sequence according to each aggregation level (S1412).

Next, the base station 1400 may map the DM-RSs using at least one of the resources of the data area, using a DM-RS (Demodulation Reference Signal) resource differently from other areas (S1414).

The base station 1400 may deliver the information indicating the DM-RS resource according to at least one of the aggregation level, the transmission method, and the E-PDCCH search space to the terminal through higher layer signaling, for example, RRC signaling (S1416). In more detail, the base station transmits information on whether to use a DM-RS port and scrambling to be used when transmitting an E-PDCCH to each RRC.

The base station 1400 transmits a radio signal including information through the E-PDCCH, the DM-RS, and the PDSCH mapped to the corresponding area (S1418).

The terminal 1401 receives a radio signal from a base station and selects one subspace of a time-frequency search space (S1420). The subspace means each unit when the search space is composed of one or more units. This unit may be a resource block (RB) or a physical resource block pair (PRB) pair as described above, but is not limited thereto.

The terminal 1401 checks the DM-RS resource for the subspace of the selected search space (S1422). At this time, the terminal grasps the DM-RS base sequence generated by the cell ID determined through the broadcasting system information. The terminal 1401 is a basic information on the DM-RS received from the base station with the DM-RS base sequence (DM-RS ports, scrambling use or not) to identify the DM-RS resources for the subspace of the selected search space Etc.).

The terminal 1401 estimates a channel based on the DM-RS (S1423). In more detail, a UE-specific DM-RS sequence is obtained using a DM-RS base sequence and a scrambling index generated by a cell ID. Channel estimation is performed on the areas allocated for the E-PDCCH using the UE-specific DM-RS sequence and DM-RS port information.

The UE 1401 attempts E-PDCCH detection according to channel estimation (S1424).

The terminal 1401 determines whether the E-PDCCH is detected according to the channel estimation (S1426).

If the E-PDCCH is detected according to channel estimation, the UE 1401 demodulates the detected E-PDCCH and detects the PDSCH using the band and decoding information of the PDSCH (S1428).

If the E-PDCCH is not detected according to channel estimation, the UE 1401 determines whether the E-PDCCH is detected for all search spaces (S1430).

If it is determined that the detection of the E-PDCCH has not been performed for all the search spaces, the process repeats steps S1420 to S1424 and ends when it is determined that the search has been performed.

Referring to FIG. 14, an apparatus for transmitting a radio signal by mapping an E-PDCCH to a resource in combination with a base station or a base station according to another embodiment includes a control unit 1500, a mapping unit 1520, a transceiver 1530, and a channel. It includes all or part of the information verification unit 1510.

The controller 1500 controls the channel information checker 1510, the mapper 1520, and the transceiver 1530.

The mapping unit 1520 maps an extended PDCCH (E-PDCCH) to be transmitted to the UE to a resource of the data region, and is based on at least one of an aggregation level or a transmission scheme of the E-PDCCH to resources of the data region. Differently, DM-RS is mapped using a DM-RS (Demodulation Reference Signal) resource. Here, the E-PDCCH may be mapped to the same port as the previous DM-RS port. In addition, the mapping unit 1520 may map DM-RSs using at least one of the resources of the data region using DM-RS (Demodulation Reference Signal) resources differently from other regions when there are two or more resources of the data region. .

On the other hand, the mapping unit 1520 is determined (or configured, assigned) DM-RS for each data area available for E-PDCCH (Extended PDCCH) transmission according to the transmission scheme and aggregation level used for E-PDCCH transmission. E-PDCCH and DM-RS may be mapped to a port (Demodulation Reference Signal port).

As described above, the DM-RS resource is at least one of a DM-RS port and a scrambling index, and a transmission scheme of the E-PDCCH may be one of a localized mapping, a distributed mapping, and a mixture thereof. .

The transceiver 1530 transmits a radio signal including the E-PDCCH and the DM-RS to the terminal and provides a function of receiving the radio signal from the terminal. The transceiver 1530 may transmit a radio signal including the PDSCH to the terminal.

In addition, the transceiver 1530 may transmit information on the DM-RS port to the terminal through higher layer signaling, system information, or in the control information of the control region.

The channel information checking unit 1510 checks the state of the channel and the wireless network provided by the terminal or separately measured.

Referring to FIG. 15, an apparatus for receiving a radio signal to which an E-PDCCH is mapped in combination with a terminal or a terminal according to another embodiment may include a controller 1600, a detection unit 1620, a transceiver 1630, and channel information. It includes all or part of the providing unit 1610.

The transceiver 1630 receives a radio signal including an extended PDCCH (E-PDCCH) and a DM-RS from the base station, and transmits channel information to the terminal. The transceiver 1630 may receive a radio signal including the PDSCH from the base station.

On the other hand, the transceiver 1630 is a DM-RS port (Demodulation Reference) determined for each data area available for E-PDCCH (Extended PDCCH) transmission from the base station according to the transmission scheme and aggregation level used for E-PDCCH transmission A wireless signal including an E-PDCCH and a DM-RS (Demodulation Reference Signal) mapped to a signal port may be received.

In addition, the detection unit 1620 is configured to set the received radio signal using another DM-RS (Demodulation Reference Signal) resource according to at least one of an aggregation level or transmission scheme of the E-PDCCH in the resource of the data region. Blind detection of the DM-RS (Demodulation Reference Signal), and blind detection of the E-PDCCH in the resource of the data region for the received radio signal using the DM-RS. The detection unit 1620 may blindly detect a demodulation reference signal (DM-RS) set by using a demodulation reference signal (DM-RS) resource for at least one of the resources of the data region unlike another region. Can be.

As described above, the channel information providing unit 1610 generates information on the channel state checked by the user terminal so that the channel information may be provided to the base station. Of course, this information is provided to the base station through the wireless signal transmission process of the transceiver 1630 through the control unit 1600. The controller 1600 controls the transceiver 1630, the detection unit 1620, and the channel information provider 1610. In addition, when the blind detection is completed, the controller 1600 decodes the E-PDCCH.

According to the above embodiments, the blind detection complexity of the E-PDCCH is set because DM-RS resources used by each UE are set differently according to an aggregation level and a transmission scheme of the E-PDCCH received by the UE. It is possible to support E-PDCCH multiplexing more smoothly without increasing the number.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited thereto. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority under Patent Application No. 10-2011-0147335, filed in South Korea on December 30, 2011, under Section 119 (a) (35 USC § 119 (a)). All content is incorporated by reference in this patent application. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims

Determining, for each data region available for Extended PDCCH (E-PDCCH) transmission, a DM-RS port (Demodulation Reference Signal Port) according to a transmission scheme and aggregation level used for E-PDCCH transmission; And

And mapping the E-PDCCH and the DM-RS to the determined DM-RS port.
The method of claim 1,

And the coupling level is at least one of coupling levels 2, 4 and 8.
The method of claim 1,

The transmission method of the E-PDCCH is one of a localized mapping (localized mapping) and distributed mapping (distributed mapping) resource mapping method of the base station.
The method of claim 1,

Resource mapping of the base station characterized in that the information on the DM-RS port is transmitted to the terminal through higher layer signaling, through system information, or included in control information of a control region. Way.
For each data area available for E-PDCCH (Extended PDCCH) transmission from the base station, E-mapped to a DM-RS port (Demodulation Reference Signal port) determined according to the transmission scheme and aggregation level used for E-PDCCH transmission. Receiving a radio signal including a PDCCH and a demodulation reference signal (DM-RS); and

E-PDCCH receiving method of the terminal comprising the step of detecting the E-PDCCH using the DM-RS from the received radio signal.
The method of claim 5,

The coupling level is at least one of the coupling level 2, 4, 8 E-PDCCH receiving method of the terminal.
The method of claim 5,

The E-PDCCH transmission method of the E-PDCCH is one of a localized mapping (localized mapping) and distributed mapping (distributed mapping).
The method of claim 5,

The information on the DM-RS port is received from the base station through higher layer signaling, through system information, or included in control information of a control region. How to receive PDCCH.
For each data area available for E-PDCCH (Extended PDCCH) transmission, E-PDCCH and DM- at the DM-RS port (Demodulation Reference Signal port) determined according to the transmission scheme and aggregation level used for E-PDCCH transmission. A mapping unit for mapping the RS; And

And a transceiver for transmitting a radio signal including the E-PDCCH and the DM-RS.
The method of claim 9,

The transceiver unit,

And transmitting the information on the DM-RS port to the terminal through higher layer signaling, through system information, or in the control information of a control region.
For each data area available for E-PDCCH (Etended PDCCH) transmission from the base station, E-mapped to a DM-RS port (Demodulation Reference Signal port) determined according to the transmission scheme and aggregation level used for E-PDCCH transmission. A transceiver for receiving a radio signal including a PDCCH and a demodulation reference signal (DM-RS); And

And a detection unit for detecting the E-PDCCH using the DM-RS from the received radio signal.
The method of claim 11,

The transceiver unit is characterized in that the information contained in the upper layer signaling, system information (system information) or control region (Control region) to receive information on the DM-RS port from the base station.