WO2013100542A1

WO2013100542A1 - Apparatus and method for transmitting control information in wireless communication system

Info

Publication number: WO2013100542A1
Application number: PCT/KR2012/011435
Authority: WO
Inventors: 김종남
Original assignee: 주식회사 팬택
Priority date: 2011-12-30
Filing date: 2012-12-26
Publication date: 2013-07-04
Also published as: KR20130078137A

Abstract

The present invention relates to an apparatus and a method for transmitting control information in a wireless communication system. To that end, a method for transmitting control information via a terminal is disclosed in the present specification comprising the steps of: receiving, from a transmission point, physical information related to a reception point operating as one cooperative set in accordance with a tranceiving method for transmission points and coordinated multiple points(CoMP); receiving a physical downlink control channel (PDCCH) from the transmission point; deriving a first control channel entity (CCE), which is mapped to the PDCCH, and, on the basis of the physical information, deriving an uplink control channel (PUCCH) resource, for a terminal, from within a resource domain of a PUCCH related to the reception point; and transmitting the PUCCH to the reception point by means of the derived PUCCH resource. An effective use of resources is made possible by instructing so as to not waste or overlap the PUCCH transmission resources when a downlink transmission point and a uplink reception point, which form a CoMP cooperation set in a CoMP system, do not match .

Description

Apparatus and method for transmitting control information in wireless communication system

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting control information in a wireless communication system.

In order to increase the performance and communication capacity of a wireless communication system, multi-cell cooperation has been introduced. Multi-cell coordination is also referred to as cooperative multiple point (CoMP) transmission and reception.

CoMP includes a beam avoidance technique in which neighboring cells cooperate to mitigate interference to a user at a cell boundary, and a joint transmission technique in which neighboring cells cooperate to transmit the same data.

Next-generation wireless communication systems, such as Institute of Electrical and Electronics Engineers (IEEE) 802.16m or 3rd Generation Partnership Project (3GPP) long term evolution (LTE) -Advanced, are located at cell boundaries and are subject to severe interference from adjacent cells. In order to solve this problem, CoMP can be considered.

Various scenarios are possible with this CoMP. There is an intra-site CoMP with multiple cells around one base station, and a plurality of high-power remote radio heads (RRHs) around one macro cell. There are high-power RRH CoMPs that exist, and low-power RRHs exist around one macro cell, but the cell IDs of the RRHs and the cell IDs of the macro cells are not the same. There is a low power RRH CoMP.

An object of the present invention is to provide an apparatus and method for transmitting control information in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for allocating PUCCH resources for a decoupled terminal in a cooperative multipoint transmission / reception scheme.

Another technical problem of the present invention is to provide an apparatus and method for transmitting physical information about a reception point to an RRC message to a decoupled terminal in a cooperative multipoint transmission / reception scheme.

Another technical problem of the present invention is to provide an apparatus and method for performing mapping between PUCCH resources of a transmission point and PUCCH resources between a reception point in a cooperative multipoint transmission / reception scheme.

According to an aspect of the present invention, a method for transmitting control information by a terminal is provided. The method includes receiving physical information about a reception point operating as a cooperative set based on a transmission point and a coordinated multiple point transmission / reception scheme from the transmission point, Receiving a physical downlink control channel (PDCCH) from the transmission point, based on a first control channel element (CCE) index mapped to the PDCCH and the physical information; Deriving a PUCCH resource for the terminal in a resource region of a physical uplink control channel (PUCCH) relating to the UE, and transmitting a PUCCH to the receiving point using the derived PUCCH resource do.

According to another aspect of the present invention, a terminal for transmitting control information is provided. The terminal receives physical information about a reception point operating as a cooperative set based on a cooperative multipoint transmission / reception scheme from a transmission point, receives a PDCCH from the transmission point, and receives a PUCCH from the transmission point. And a resource calculating unit for deriving a PUCCH resource for the terminal in the resource region of the PUCCH for the receiving point based on the first CCE index mapped to the PDCCH and the physical information. The RF unit may transmit the PUCCH to the receiving point by using the derived PUCCH resource.

In the CoMP system, when the downlink transmission point and the uplink reception point constituting the CoMP cooperative set do not coincide, efficient resource utilization is possible by instructing not to waste or overlap the PUCCH transmission resources of the UE.

1 is a block diagram showing a wireless communication system to which the present invention is applied.

2 and 3 schematically show the structure of a radio frame to which the present invention is applied.

4 shows the operation of the CoMP system to which the present invention is applied.

FIG. 5 is a graph showing a relationship between distance and power due to decoupling in a CoMP system to which the present invention is applied.

6 is a diagram illustrating an example of a method of allocating a resource of an uplink control signal to which the present invention is applied.

7 is a view for explaining another example of a method for allocating a resource of an uplink control signal to which the present invention is applied.

8 is a flowchart illustrating a method of transmitting control information according to an embodiment of the present invention.

9 is a flowchart illustrating a method of transmitting control information according to another embodiment of the present invention.

10 is an explanatory diagram illustrating mapping between PUCCH resources according to an embodiment of the present invention.

11 is a flowchart illustrating a method of transmitting control information according to another embodiment of the present invention.

12 is a block diagram illustrating a terminal, a transmission point, and a reception point according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even though they are shown in different drawings. The present specification describes a communication network, and the work performed in the communication network is performed in the process of controlling the network and transmitting data in a system (for example, a base station) that manages the communication network, or a terminal linked to the network. Work can be done in

According to the embodiments of the present invention, the term 'transmitting a channel' may be interpreted to mean that information mapped through the channel or mapped to the channel is transmitted. Here, the channel may be, for example, a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical uplink control channel (PUCCH) or a physical channel. It may include a physical uplink shared channel (PUSCH).

Referring to FIG. 1, the wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data. The wireless communication system 10 includes at least one base station (BS) 11. Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c.

Cells

15a, 15b, and 15c may in turn be divided into a number of regions (called sectors).

The user equipment (UE) 12 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a PDA. (personal digital assistant), wireless modem (wireless modem), a handheld device (handheld device) may be called other terms. The base station 11 generally refers to a station communicating with the terminal 12, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, an femto eNodeB, and a household It may be referred to in other terms such as a base station (HeNB), a relay, a remote radio head (RRH), and the like.

Cells

15a, 15b, and 15c should be interpreted in a comprehensive sense indicating some areas covered by the base station 11, and encompass all of the various coverage areas such as megacells, macrocells, microcells, picocells, and femtocells. to be.

Hereinafter, downlink refers to a communication or communication path from the base station 11 to the terminal 12, and uplink refers to a communication or communication path from the terminal 12 to the base station 11. . In downlink, the transmitter may be part of the base station 11 and the receiver may be part of the terminal 12. In uplink, the transmitter may be part of the terminal 12 and the receiver may be part of the base station 11. There is no limitation on the multiple access scheme applied to the wireless communication system 10. Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), OFDM-FDMA, OFDM-TDMA For example, various multiple access schemes such as OFDM-CDMA may be used. These modulation techniques demodulate signals received from multiple users of a communication system to increase the capacity of the communication system. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme transmitted using different times or a frequency division duplex (FDD) scheme transmitted using different frequencies.

The wireless communication system 10 may be a Coordinated Multi Point (CoMP) system. The CoMP system refers to a communication system supporting CoMP or a communication system to which CoMP is applied. CoMP is a technique for adjusting or combining signals transmitted or received by multi transmission / reception (Tx / Rx) points. CoMP can increase data rates and provide high quality and high throughput.

The transmission / reception point may be defined as a component carrier or a cell, or a base station (macro base station, pico base station (Fico eNodeB), femto base station (Femto eNodeB), etc.), or a remote radio head (RRH). Alternatively, the transmission / reception point may be defined as a set of antenna ports. The transceiver may transmit information about the set of antenna ports to the terminal through radio resource control (RRC) signaling. Therefore, a plurality of transmission points in one cell can be defined as a set of antenna ports.

The base station 11 of the cell 15a, the base station 11 of the cell 15b and the base station 11 of the cell 15c may configure multiple transmission / reception points. For example, the multiple transmit / receive points may be base stations of a macro cell forming a homogeneous network. The multiple transmit / receive points may also be base stations of macro cells and base stations of pico cells within macro cells, forming a heterogeneous network. In addition, the multiple transmission / reception points may be a base station of the macro cell and a remote radio unit (RRU) in the macro cell. In addition, the multiple transmission / reception points may be RRHs belonging to the base station of the macro cell and RRHs belonging to the base station of the heterogeneous cell (e.g. pico cell) in the macro cell.

The CoMP system may selectively apply CoMP. That is, the CoMP system may or may not apply CoMP to a communication operation. A mode in which a CoMP system performs communication using CoMP is called a CoMP mode, and a mode other than the CoMP system is called a normal mode. For example, if CoMP is determined to be advantageous, the CoMP system may operate in CoMP mode. On the other hand, if CoMP is determined to be disadvantageous, the CoMP system may operate in a normal mode.

The terminal 12 may be a CoMP terminal. The CoMP terminal is a component of the CoMP system and performs communication with a CoMP cooperating set. Like the CoMP system, the CoMP terminal may operate in the CoMP mode or in the normal mode. The CoMP cooperative set may be a set of transmitting / receiving points that directly or indirectly participate in data transmission in a time-frequency resource for a CoMP terminal. For example, the base station 11 of the cell 15a, the base station 11 of the cell 15b, and the base station 11 of the cell 15c may form a CoMP cooperative set. Also, the transmit and receive points do not necessarily have to provide the same coverage. For example, base station 11 of cell 15a may be a base station providing a macro cell, and base station 11 of cell 15b may be an RRH.

Participating directly in data transmission or reception may mean that transmission / reception points transmit downlink data to the CoMP terminal or receive uplink data from the CoMP terminal. Indirect participation in data transmission or reception may mean that the transmit / receive points do not transmit downlink data to the CoMP terminal or receive uplink data from the CoMP terminal, but contribute to making user scheduling / beamforming decisions. Can be.

The CoMP terminal may simultaneously receive signals from the CoMP cooperative set or transmit signals simultaneously to the CoMP cooperative set. At this time, the CoMP system may minimize the interference effect between the CoMP cooperation sets in consideration of the channel environment of each cell constituting the CoMP cooperation set.

When the CoMP terminal performs uplink transmission, a channel environment is formed between the reception point and the CoMP terminal. For example, the channel environment is a set of parameters that affect scheduling for a CoMP terminal, such as a frequency bandwidth allocated to the CoMP terminal and a downlink pathloss (PL). The channel environment is formed individually for each receiving point. This means that the channel environment may be different for each receiving point. If the channel environment is different for each receiving point, the CoMP terminal should set uplink transmission power differently for each receiving point. Therefore, the CoMP terminal needs to know how the channel environment is different for each receiving point.

When operating a CoMP system, various scenarios are possible. The first scenario is an intra-site CoMP scenario in which a plurality of cells exist around one base station. The second scenario is a high-power CoMP scenario in which a plurality of high-power RRHs exist around one macro cell. The third scenario is a CoMP scenario in which a low-power RRH exists around one macro cell but the physical cell ID of the RRH and the physical cell ID of the macro cell are not the same. The fourth scenario is a CoMP scenario in which a low-power RRH exists around one macro cell, but the physical cell ID of the RRH and the physical cell ID of the macro cell are the same. Therefore, in the fourth scenario, the transmission pattern of the reference signal determined by the cell ID also matches.

The transmission and reception point to which the present invention is applied may include a base station, a cell, or an RRH. That is, the base station or the RRH may be a transmission / reception point. Meanwhile, the plurality of base stations may be multiple transmission / reception points, and the plurality of RRHs may be multiple transmission / reception points. Of course, the operation of all base stations or RRH described in the present invention can be equally applied to other types of transmission and reception points.

The layers of the radio interface protocol between the terminal and the base station are based on the lower three layers of the Open System Interconnection (OSI) model, which is well known in the communication system. It may be divided into a second layer L2 and a third layer L3. Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel.

There are several physical channels used in the physical layer. The PDCCH includes a resource allocation and transmission format of a downlink shared channel (DL-SCH), resource allocation information of an uplink shared channel (UL-SCH), and a physical downlink shared channel. Resource allocation of a higher layer control message such as a random access response transmitted on a PDSCH, a set of transmission power control (TPC) commands for individual terminals in an arbitrary terminal group, and the like. have. A plurality of PDCCHs may be mapped and transmitted in a control region of a subframe, and the terminal may monitor the plurality of PDCCHs.

Control information of the physical layer mapped to the PDCCH is referred to as downlink control information (DCI). That is, DCI is transmitted through the PDCCH. The DCI may include an uplink or downlink resource allocation field, an uplink transmission power control command field, a control field for paging, a control field for indicating a random access response (RA response), and the like.

DCI has different uses according to its format, and fields defined in DCI are also different. Table 1 shows DCIs according to various formats.

Table 1

DCI format	Explanation
0	Used for scheduling of PUSCH (Uplink Grant)
One	Used for scheduling one PDSCH codeword in one cell
1A	Used for simple scheduling of one PDSCH codeword in one cell and random access procedure initiated by PDCCH command
1B	Used for simple scheduling of one PDSCH codeword in one cell using precoding information
1C	Used for brief scheduling of one PDSCH codeword and notification of MCCH change
1D	Used for simple scheduling of one PDSCH codeword in one cell containing precoding and power offset information
2	Used for PDSCH scheduling for UE configured in spatial multiplexing mode
2A	Used for PDSCH scheduling of UE configured in long delay CDD mode
2B	Used in transmission mode 8 (double layer transmission)
2C	Used in transmission mode 9 (multi-layer transmission)
3	Used to transmit TPC commands for PUCCH and PUSCH with power adjustment of 2 bits
3A	Used to transmit TPC commands for PUCCH and PUSCH with single bit power adjustment
4	Used for scheduling of PUSCH (Uplink Grant). In particular, it is used for PUSCH scheduling for a terminal configured in a spatial multiplexing mode.

Referring to Table 1, DCI format 0 is uplink scheduling information, format 1 for scheduling one PDSCH codeword, format 1A for compact scheduling of one PDSCH codeword, and very simple of DL-SCH. Format 1C for scheduling, format 2 for PDSCH scheduling in closed-loop spatial multiplexing mode, format 2A for PDSCH scheduling in open-loop spatial multiplexing mode, and uplink channel Formats 3 and 3A for transmission of a transmission power control (TPC) command.

Each field of the DCI is sequentially mapped to _n information bits a ₀ to a _n-1 . For example, if DCI is mapped to information bits of a total of 44 bits in length, each DCI field is sequentially mapped to a ₀ to a ₄₃ . DCI formats 0, 1A, 3, and 3A may all have the same payload size. DCI format 0 may be called an uplink grant.

2 and 3, the downlink radio frame may include 10 subframes. One subframe includes two slots. The time (length) of transmitting one subframe is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

One slot may include a plurality of symbols in the time domain. For example, in a wireless system using orthogonal frequency division multiple access (OFDMA) in downlink (DL), the symbol may be an orthogonal frequency division multiplexing (OFDM) symbol. Meanwhile, the representation of the symbol period in the time domain is not limited by the multiple access scheme or the name. For example, the plurality of symbols in the time domain may be a Single Carrier-Frequency Division Multiple Access (SC-FDMA) symbol, a symbol interval, or the like in addition to the OFDM symbol.

The number of OFDM symbols included in one slot may vary depending on the length of a cyclic prefix (CP). For example, in case of a normal CP, one slot may include 7 OFDM symbols, and in case of an extended CP, one slot may include 6 OFDM symbols.

One slot includes a plurality of subcarriers in the frequency domain and seven OFDM symbols in the time domain. A resource block (RB) is a resource allocation unit. If a resource block includes 12 subcarriers in the frequency domain, one resource block may include 7 × 12 resource elements (REs).

The resource element represents the smallest frequency-time unit to which the modulation symbol of the data channel or the modulation symbol of the control channel is mapped. If there are M subcarriers on one OFDM symbol, and one slot includes N OFDM symbols, one slot includes MxN resource elements.

Referring to FIG. 4, a macro base station (eNodeB) 400 that is a main transmission / reception point and an RRH 405 that is a secondary transmission / reception point form one cooperative set. The macro base station 400 and the RRH 405 communicate with the UE 410 in a CoMP manner. The macro base station 400 transmits a downlink signal to the terminal 410, where a downlink path loss (PL_DL) occurs. The terminal 410 transmits an uplink signal to the RRH 405, where an uplink path loss (PL_UL) occurs. This is a case where a transmission point for transmitting a downlink signal and a reception point for receiving an uplink signal are different. In this way, the transmission / reception point for transmitting the downlink signal and the transmission / reception point for receiving the uplink signal are separated (or different from each other). This is called up / down (UL / DL) decoupling. For example, by decoupling, the macro base station 400 transmits the PDCCH and PDSCH to the terminal 410 as a transmission point, and the RRH 405 is a PUCCH, PUSCH and uplink control signal from the terminal 410 as a reception point. Receive

UL / DL decoupling results from a difference in transmit power between the macro base station 400 and the RRH 405. In FIG. 5, the dashed-dotted line 500 represents the magnitude of the transmission power of the macro base station according to the distance, and the solid line 505 represents the magnitude of the transmission power according to the distance of the low power node (LPN). LPN includes the RRH as a low power transmission point. The macro base station transmits higher transmission power than the LPN, and both the macro base station and the LPN attenuate the magnitude of the transmission power at a constant rate with distance. The point where the magnitude of the power transmitted from the two transmission points (macro base station, LPN) from the viewpoint of the UE (UE) is the point where the dashed line 500 and the solid line 505 intersect. If the terminal is located on the left side at the point where two lines cross (RSRP boundary), the transmission power from the macro base station is large. On the contrary, if the terminal is located on the right side, the transmission power from the LPN is large. In the terminal, receiving downlink data from the macro base station is advantageous in terms of reception power.

On the other hand, from the standpoint of uplink transmission of the terminal, the terminal is located on the left side based on the patholoss boarder where the dashed line 500 and the dotted line 510 meet. Sending the link is a gain. Accordingly, it is advantageous in terms of power transmission that the terminal receives the downlink signal from the macro base station and transmits the uplink signal to the LPN.

In this way, when the UE can independently select the uplink receiving point and the downlink transmitting point in the CoMP system, the data can be transmitted to an optimal transmitting / receiving point capable of receiving a signal of the terminal. It becomes possible. This can reduce the battery consumption by reducing the power consumption of the terminal, and the low power transmission of the terminal can also reduce the influence of interference that can affect the uplink transmission of the neighboring terminal.

The PUCCH resource for ACK / NACK transmission of the UE is determined by the first control channel element (CCE) index of the PDCCH indicating resource allocation of the PDSCH. Each cell performs independent PDCCH resource allocation. However, when the transmission point of the PDCCH and the reception point of the PUCCH are decoupled as shown in FIGS. 4 and 5, if the transmission resource (eg, ACK / NACK resource) of the PUCCH of the UE is determined by the PDCCH transmitted by the downlink transmission point, between terminals Conflict of PUCCH resources may occur. For example, when two transmitting and receiving points A and B exist, the up / down decoupled terminal receives the PDCCH from the transmitting and receiving point A and transmits the PUCCH to the transmitting and receiving point B with the resources determined by the PDCCH. On the other hand, the UE which is not decoupled up / down may transmit the PUCCH to the transmission / reception point B by the PDCCH received from the transmission / reception point B. In this case, if independent PDCCH resource allocation is performed between the transmission and reception points A and B, a PUCCH collision may occur between two terminals. In this case, if two transceivers are configured as a CoMP cooperation set, a method of avoiding collision between two resources is required.

Referring to FIG. 6, the base station (eNodeB) explicitly informs the terminal of the location where the resource region of the dynamic PUCCH for ACK / NACK transmission starts. RRC message can be used for this. This approach is called explicit resource allocation. The CoMP _UE may receive an N ⁽¹⁾ _{PUCCH_UE} signal, which is a _UE- specific parameter, in addition to the cell-specific parameter N ⁽¹⁾ _{PUCCH_eNB} to which the CoMP UE belongs from the base station. A terminal that does not support CoMP among terminals (RRH UEs) connected to the RRH receives a cell specific _parameter N ⁽¹⁾ _{PUCCH_RRH} signal of the RRH. N ⁽¹⁾ _{PUCCH_eNB,} N ⁽¹⁾ _{PUCCH_RRH} is a cell-specific parameter is transmitted to N ⁽¹⁾ _PUCCH to the UE belonging to each cell, but in the present invention, N ⁽¹⁾ _{PUCCH_eNB,} N ⁽¹⁾ _{PUCCH_RRH} are shown.

Here, N ⁽¹⁾ _PUCCH or N ⁽¹⁾ _{PUCCH, UE} is a resource offset indicating a starting point of dynamic PUCCH format 1 allocation of the _UE . The UE transmits an ACK / NACK signal using the PUCCH resource after the resource offset, and the PUCCH resource after the resource offset is implied by the first CCE index value of the PDCCH used for allocation of the PDSCH associated with the PUCCH. Is determined.

In order to avoid interference with the base station, the RRH sets a resource offset cell specific N ⁽¹⁾ _{PUCCH_RRH} so that the PUCCH is not transmitted to the RRH in a period in which the PUCCH is transmitted to the base station and transmits it to the terminal. On the other hand, the RRH may allocate resources for PUSCH transmission of the UE in the period in which the PUCCH is transmitted to the base station. This may increase the data transmission efficiency. This is because the PUSCH can retransmit data through the transmission of the ACK / NACK signal, so the expectation of the data transmission success probability is not higher than that of the PUCCH. On the other hand, since the PUCCH expects a higher reception success probability than the data, it is preferable to block the cause of performance degradation by avoiding the interference effect of the PUCCH between two cells.

Non-CoMP terminal among the UE connected to the RRH transmits the ACK / NACK signal by using the PUCCH resource region after the resource offset N ⁽¹⁾ _{PUCCH_RRH} transmitted from the RRH. At this time, each PUCCH resource is allocated based on the first CCE index of the PDCCH transmitted by the RRH. The PUCCH resource region in the RRH includes a dynamic PUCCH resource region for a CoMP terminal. The dynamic PUCCH resource region for a CoMP terminal is used by a terminal (hereinafter also referred to as a decoupled terminal) for receiving a PDCCH from a base station and transmitting a PUCCH to the RRH. The base station transmits, to the CoMP terminal, the resource offset at which the dynamic PUCCH resource region for the CoMP terminal is to be started as a terminal specific parameter (N ⁽¹⁾ _{PUCCH, UE} ).

In the CoMP system, the base station should be able to precisely allocate the PUCCH resources to the terminal in consideration of the interference effect between the cells. To this end, as shown in FIG. 6, a PUCCH resource different from RRH terminals may be configured in the CoMP terminal, such as a dynamic PUCCH resource region for the CoMP terminal. The RRH may have a different resource region allocated for PUCCH transmission in every subframe. However, transmitting the resource offset indicating the dynamic PUCCH resource region for the CoMP terminal to the terminal by the base station in a semi-static manner may be a limitation on the efficient use of resources.

7 is a view for explaining another example of a method for allocating a resource of an uplink control signal to which the present invention is applied. This is a case where the PUCCH resource region is indicated in a semistatic manner.

Referring to FIG. 7, a dynamic PUCCH resource region for a CoMP terminal is used for PUCCH resource allocation for transmission of an ACK / NACK signal of a CoMP terminal. However, as in Case 1, a case where a PUCCH resource region (dynamic PUCCH resource region for RRH) and a PUCCH resource region for CoMP terminal overlap with or collide with each other may occur. Here, the CoMP terminal may be a decoupled terminal that receives a downlink signal from the base station and transmits an uplink signal to the RRH. In this case, PUCCH transmission of the UE connected to the RRH and PUCCH transmission of the CoMP UE may be simultaneously performed in the same resource block. Therefore, when the CoMP terminal transmits the PUCCH, the base station should inform the decoupled terminal of additional information for avoiding collision with the terminal connected to the RRH such as the PUCCH sequence and the cyclic shift.

Meanwhile, as in Case 2, there may be a case where the dynamic PUCCH resource region for the CoMP terminal does not overlap with the dynamic PUCCH resource region for the RRH terminal. In this case, the space between two PUCCH resource regions may be partially allocated to the PUSCH region. However, since the PUSCH region is divided into three parts, constraints may be placed on uplink resource allocation of the UE. For this reason, resource allocation may be possible if non-contiguous resource allocation to the terminal is possible, but it may weaken the characteristics of the uplink single carrier of the terminal and have a high peak-to-average power ratio (PAPR). Inducing phenomena may require a high performance amplifier.

Considering the phenomenon of Case1 and Case2, the dynamic PUCCH resource region for the CoMP terminal should be allocated continuously without overlapping the dynamic PUCCH resource region for the RRH terminal. To this end, a method of transmitting control information considering PUCCH resource allocation of flexible RRHs is required for every subframe.

In the context of the present invention, it is assumed that the base station and the RRH make a CoMP cooperative set and perform communication with a CoMP terminal. At this time, the CoMP terminal is a decoupled terminal and receives a downlink signal (for example, PDCCH and PDSCH) from the base station and transmits an uplink signal (for example, PUCCH and PUSCH) to the RRH. Therefore, the base station is a transmission point and the RRH is a reception point based on the CoMP system.

When the base station allocates the PUCCH resource for the CoMP terminal to the CoMP terminal to the uplink transmission band to the RRH, the CoMP terminal needs to know the reception point physical information.

As an example, the reception point physical information includes an index of a resource block including a PUCCH resource for a CoMP terminal, a PUCCH base sequence, a cyclic shift (CS), and an orthogonal covering code (OCC). ) At least one.

As another example, the reception point physical information may include a physical cell ID of a reception point, a resource offset N ⁽¹⁾ indicating a point at which a dynamic PUCCH resource of a UE belonging to an RRH starts, and a physical HARQ indicator channel transmitted by the _PUCCH and the RRH. channel: PHICH).

Referring to FIG. 8, the CoMP terminal receives reception point physical information from a transmission point (S800). Here, the transmitting point and the receiving point are elements constituting the CoMP cooperative set. For example, the transmitting point may be a base station, and the receiving point may be an RRH. Meanwhile, the CoMP terminal is a decoupled terminal and receives a downlink signal from a transmitting point and transmits an uplink signal to the receiving point.

Receiving point physical information is used to provide information about the receiving point to the terminals connected to the uplink to a receiving point other than the transmitting point among the terminals connected to the transmitting point. In more detail, the reception point physical information includes information indicating a plurality of PUCCH resource candidates in a PUCCH resource region for a CoMP terminal in a PUCCH resource region for a reception point. K PUCCH resources, such as a first PUCCH resource, a second PUCCH resource, ..., a k-th PUCCH resource, and so forth, may be PUCCH resource candidates, which are set by a transmission point or a reception point. The reception point physical information is a kind of configuration information and may have a terminal specific value. Therefore, the PUCCH resource candidate provided by the reception point physical information may be differently designated for each terminal.

The reception point physical information may include at least one of an index of a resource block including a PUCCH resource for a CoMP terminal, a PUCCH basic sequence, a cyclic shift (CS), and an orthogonal covering code (OCC).

The reception point physical information may be an RRC message generated at the RRC layer or a MAC message generated at a medium access control (MAC) layer.

The transmitting point maps a DCI including a PUCCH resource indicator field indicating one of the PUCCH resource candidates to the PDCCH and transmits the DCI to the CoMP terminal (S805). At this time, the PDSCH scheduled by the PDCCH is also transmitted.

The DCI is a new format and additionally includes n bits for the PUCCH resource indication field. For example, when n = 2, the PUCCH resource indication field indicates a specific PUCCH resource candidate according to its value as shown in the following table.

TABLE 2

PUCCH Resource Indicator Field	n ^{(1, p)} _PUCCH
00	PUCCH Resource Consideration for CoMP Terminal
01	First PUCCH Resource in PUCCH Resource Region for CoMP Terminal
10	Second PUCCH Resource in PUCCH Resource Region for CoMP Terminal
11	Third PUCCH Resource in PUCCH Resource Region for CoMP Terminal

Referring to Table 2, the PUCCH resource indication field is 2 bits. If the value of this field is 00, the UE does not consider the PUCCH resource for the CoMP UE in the PUCCH resource region of the reception point and follows the existing PUCCH transmission method. it means. On the other hand, when the CoMP UE receives a PDCCH having a corresponding field value of 01, 10, or 11 from the transmitting point, it transmits the PUCCH to the receiving point using the indication indicated in the corresponding PUCCH resource indication field among the PUCCH resource candidates instead of the existing PUCCH transmission resource do. In setting the PUCCH resource candidates as the reception point physical information, the transmitting point may set the PUCCH resource in consideration of the dynamic change of the PUCCH resource at the receiving point.

The CoMP terminal blindly decodes the PDCCH in consideration of the DCI including the PUCCH resource indication field and derives a PUCCH resource indicated by the PUCCH resource indication field among the PUCCH resource candidates (S810).

The CoMP terminal transmits the PUCCH to the reception point by using the derived PUCCH resource (S815).

Referring to FIG. 9, the transmission point transmits reception point physical information to the CoMP terminal (S900). Here, the transmitting point and the receiving point are elements constituting the CoMP cooperative set, the transmitting point may be a base station, and the receiving point may be an RRH. Meanwhile, the CoMP terminal is a decoupled terminal and receives a downlink signal from a transmitting point and transmits an uplink signal to the receiving point.

Receiving point physical information is used to provide information about the receiving point to the terminals connected to the uplink to a receiving point other than the transmitting point among the terminals connected to the transmitting point. In more detail, the reception point physical information includes at least one of a physical cell ID (CID) of the reception point, a capacity of the PHICH of the reception point, and a resource offset N ⁽¹⁾ _PUCCH at the reception point (RRH). do.

The receiving point transmits the PCFICH to the CoMP terminal (S905), and the transmitting point transmits the PDCCH and PDSCH to the CoMP terminal (S910). The order in which the CoMP UE receives the PCFICH, the PDCCH, and the PDSCH is not necessarily the order described, and may first receive the PDCCH and the PDSCH, and then receive the PCFICH. Since the CoMP terminal knows the physical cell ID of the receiving point from the receiving point physical information, the CoMP terminal detects a physical control format indicator channel (PCFICH) transmitted from the receiving point using the physical cell ID of the receiving point ( S915).

The PCFICH is a physical channel to which CFIs indicating the number of SC-FDMA symbols constituting the control region of the reception point are mapped, and is flexible in every subframe. From the PCFICH, the CoMP terminal finds the number of SC-FDMA symbols forming the control area of the reception point. Since the total number of resources of the PUCCH used for the transmission of the ACK / NACK signal is affected by the N _CCE of the PDCCH of the receiving point, SC-FDMA symbol to form the control area of the receiving point to derive the N _CCE value This is because the number of. Here, N _CCE means the total number of _CCEs of the corresponding subframe. On the other hand, PHICH is a physical channel to which the ACK / NACK signal transmitted to the receiver is mapped, the capacity of the PHICH is a parameter that the CoMP terminal needs to know for the accurate calculation of N _CCE along with the PCFICH.

The CoMP terminal calculates N _CCE to be used at the reception point based on the number of SC-FDMA symbols constituting the PCFICH and the capacity of the PHICH (S920). From N _CCE , the CoMP UE can obtain the total size of the dynamic PUCCH resource region to be used at the receiving point, and using the resource offset N ⁽¹⁾ _{PUCCH, RRH} received from the transmitting point _, the CoC UE determines the starting point of the PUCCH resource region for the CoMP UE. Able to know.

The PUCCH resource required for the decoupled CoMP terminal may be larger than the PUCCH resource for the actually allocated CoMP terminal. For example, if the PUCCH resource for the CoMP terminal in the PUCCH resource region of the receiving point is determined by the CCE index of the PDCCH of the transmitting point, the size of the PUCCH resource region to be reserved for a limited number of CoMP terminals may be considerable. Can be. In other words, the number of resource blocks allocated to the PUCCH resource region for the CoMP terminal may be smaller than the number of resource blocks used for dynamic PUCCH resource allocation at the transmission point. Accordingly, in order to derive a PUCCH resource for a CoMP terminal, mapping between PUCCH resources such that dynamic PUCCH resources at a relatively large number of transmission points are mapped to a PUCCH resource for a CoMP terminal at a relatively few reception points (Inter-PUCCH resource) mapping must be made.

As illustrated in FIG. 10, mapping between PUCCH resources means mapping of PUCCH resources according to the first CCE index of the CoMP terminal at the transmitting point to the PUCCH resource index for the CoMP terminal at the receiving point.

Referring to FIG. 10, the PUCCH resources of the transmitting point are more than the PUCCH resources for the CoMP terminal of the receiving point. When the PUCCH index for the CoMP terminal is implicitly generated based on the CCE index of the transmission point in the conventional manner, it may be out of the range of the PUCCH resource index for the CoMP terminal of the reception point. The CoMP terminal must perform mapping between PUCCH resources to be located within the range of the PUCCH resource index for the CoMP terminal of the reception point. For example, in FIG. 10, PUCCH resource indexes a, b, and c of a transmitting point are mapped to PUCCH resource indexes z, y, and x for CoMP terminals of a receiving point, respectively, by mapping between PUCCH resources.

As an embodiment, the CoMP terminal may perform mapping between PUCCH resources based on Equations 1 to 3. Equation 1 generalizes a process of determining a PUCCH resource index for a CoMP terminal of a reception point.

Equation 1

Referring to Equation 1, n ⁽¹⁾ _{PUCCH for CoMP} is a PUCCH resource index to be used in the PUCCH resource region for the CoMP terminal, n ⁽¹⁾ _{PUCCH, eNB} is the first CCE of the PDCCH to the CoMP terminal to the CoMP terminal Index of the resource allocated by the index, N _{CCE, RRH} is the total number of CCE at the receiving point (RRH). Accordingly, the CoMP terminal may configure a small PUCCH resource region as shown in FIG. 10 as a PUCCH resource region for the CoMP terminal. Accordingly, the transmission point determines the CCE index of the PDCCH in consideration of the PUCCH resources to be allocated to the CoMP terminal through mapping between the PUCCH resources in allocating the PUCCH resources of the CoMP terminal.

Referring back to FIG. 9, the CoMP terminal derives PUCCH resources n ⁽¹⁾ _{PUCCH for CoMP} for the CoMP terminal based on the mapping between PUCCH resources (S925), and transmits the PUCCH to the reception point using the derived PUCCH resources. (S930).

Referring to FIG. 11, the transmission point transmits reception point physical information to the CoMP terminal (S1100). Here, the transmitting point and the receiving point are elements constituting the CoMP cooperative set, the transmitting point may be a base station, and the receiving point may be an RRH. Meanwhile, the CoMP terminal is a decoupled terminal and receives a downlink signal from a transmitting point and transmits an uplink signal to the receiving point.

Receiving point physical information is used to provide information about the receiving point to the terminals connected to the uplink to a receiving point other than the transmitting point among the terminals connected to the transmitting point. In more detail, the reception point physical information includes at least one of a physical cell ID of a reception point, a capacity of a PHICH of a reception point, and a resource offset N ⁽¹⁾ _{PUCCH and RRR} at a reception point (RRH).

The transmitting point masks the cyclic redundancy check (CRC) bits of the PDCCH by the cell-radio network temporar identifier (C-RNTI) and the PCFICH transmitted by the receiving point. In operation S1105, the masked PDCCH and PDSCH are transmitted to the CoMP terminal. C-RNTI is unique information of the CoMP terminal. Masking is also called scrambling. While the CoMP terminal receives the PCFICH from the receiving point and receives the masked state on the PDCCH of the transmitting point, the CoMP terminal limits the number of RNTIs that can be allocated to the CoMP terminal. However, if there is not much information masked on the CRC, the complexity is greatly increased. The PCFICH capacity can be informed to the CoMP terminal without increasing the number of additional bits within the range that does not increase.

The specific process of masking according to the present invention is as follows. In fact, in antenna selection for uplink data transmission, antenna selection information is transmitted through masking of the C-RNTI. The payload of the PDCCH is called a ₀ , a ₁ , a ₂ , ..., a _A-1 , and the parity bits are p ₀ , p ₁ , p ₂ , ..., p _L Let's say _-1 . As a result of the calculation, the parity bits are converted into the sequences b ₀ , b ₁ , b ₂ , ..., b _B-1 , where B = A + L.

k = 0, 1, 2, ...., when A-1 il c and _{_{k = b k, k = A}} , A + 1, A + 2, if ..., A + 15 il c _k = ( b _k + x _{rnti, kA} + x _{CFI, kA} ) _mod 2. As an example, X _{CFI, kA} may be defined as shown in the following table according to the CFI value. Of course, each CFI value and antenna selection mask information may be configured as another example.

TABLE 3

Transmit Antenna Selection of CoMP Terminal	Antenna Selection Mask <x _{CFI, 0} , x _{CFI, 1} , x _{CFI, 2} , ...., x _{CFI, 15} >
CFI = 3	<0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>
CFI = 2	<0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1>
CFI = 1	<0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0>

The CoMP UE calculates N _CCE to be used at the reception point based on the number of SC-FDMA symbols constituting the PDCCH and the capacity of the PHICH by demasking the CRC of the PDCCH (S1110). The CoMP terminal derives a PUCCH resource n ⁽¹⁾ _{PUCCH for CoMP} for the CoMP terminal based on the mapping between the PUCCH resources of Equation 1 (S1115) and uses the derived PUCCH resource as a reception point. It transmits (S1120).

Referring to FIG. 12, the terminal 1200 includes an RF unit 1205 and a processor 1210, and the processor 1210 includes a message processing unit 1211 and a resource calculating unit 1212.

The transmission point 1260 and the reception point 1250 are elements constituting a CoMP cooperative set. The transmission point 1260 may be a macro base station, and the reception point 1250 may be an RRH. Meanwhile, the terminal 1200 is a decoupled CoMP terminal, receives a downlink signal from the transmission point 1260, and transmits an uplink signal to the reception point 1250. The transmission point 1260 generates the reception point physical information, the PDCCH, and the PDSCH and transmits the generated physical information to the terminal 1200.

As an example, the transmission point 1260 masks the CRC bits of the PDCCH by the C-RNTI of the terminal 1200 and the PCFICH transmitted by the reception point 1250, and the masked PDCCH and PDSCH to the terminal 1200. Can transmit For example, examples of CFI masked to the CRC bit are shown in Table 3 above.

Meanwhile, the transmission point 1260 performs scheduling (or allocation) of the PUCCH resource region of the reception point 1250. For scheduling of the PUCCH resource region, for example, the transmission point 1260 distinguishes between the dynamic PUCCH resource region for the RRH terminal and the dynamic PUCCH resource region for the CoMP terminal as shown in FIG. 6 or FIG. (1) setting the PUCCH and RHR. The reception point 1250 allocates a dynamic PUCCH resource region for the terminal 1200 in the PUCCH resource region.

The RF unit 1205 receives, descrambles, and decodes the reception point physical information, the PDCCH, and the PDSCH from the transmission point 1260, and then sends a DCI mapped to the reception point physical information and the PDCCH to the message processing unit 1211. Receiving point physical information is used to provide information about the receiving point to the terminals connected to the uplink to a receiving point other than the transmitting point among the terminals connected to the transmitting point. The RF unit 1205 receives and decodes the PCFICH based on the physical cell ID of the reception point 1250, and then transmits the CIF information to the message processing unit 1211.

The DCI mapped to the PDCCH may include a PUCCH resource indication field indicating one of the PUCCH resource candidates. DCI is a new format and additionally includes n bits for the PUCCH resource indication field. For example, when n = 2, the PUCCH resource indication field indicates a specific PUCCH resource candidate according to its value as shown in the following table.

Table 4

The message processing unit 1211 analyzes the reception point physical information received from the RF unit 1205, the DCI mapped to the PDCCH, and the CFI information, and inputs them to the resource calculation unit 1212.

As an example, the reception point physical information includes information indicating a plurality of PUCCH resource candidates in a PUCCH resource region for a CoMP terminal in a PUCCH resource region for a reception point. The reception point physical information may further include at least one of an index of a resource block including a PUCCH resource for the terminal 1200, a PUCCH basic sequence, a cyclic shift (CS), and an orthogonal covering code (OCC). In this case, the resource calculator 1212 derives the PUCCH resource indicated by the PUCCH resource indication field among the PUCCH resource candidates known by the reception point physical information.

As another example, the reception point physical information may include a physical cell ID of the reception point 1250, a resource offset N ⁽¹⁾ _PUCCH indicating a point where a PUCCH resource for a CoMP terminal starts in the PUCCH resource region for the reception point 1250 _, At least one of the capacity of the PHRR transmitted from the _RRH and the receiving point (1250). In this case, the resource calculator 1212 calculates N _CCE to be used at the reception point 1250 based on the number of SC-FDMA symbols constituting the PCFICH and the capacity of the PHICH. From the calculated N _CCE , the resource calculator 1212 may obtain the total size of the dynamic PUCCH resource region to be used at the reception point 1250, and obtain a resource offset N ⁽¹⁾ _{PUCCH, RRH} received from the transmission point 1260. In this case, the starting point of the PUCCH resource region for the terminal 1200 can be known.

The resource calculator 1212 performs mapping between PUCCH resources to be located within a range of a PUCCH resource index for the CoMP terminal of the reception point 1250. For example, the resource calculator 1212 may perform mapping between PUCCH resources based on Equations 1 to 3 above. The resource calculator 1212 may derive the PUCCH resource n ⁽¹⁾ _{PUCCH for CoMP} for the terminal 1200 based on the mapping between the PUCCH resources.

The RF unit 1205 transmits the PUCCH to the reception point 1250 using the PUCCH resource derived by the resource calculation unit 1212.

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.

Claims

In the method of transmitting control information by the terminal,

Receiving physical information about a reception point operating as a cooperative set based on a transmission point and a coordinated multiple point transmission / reception scheme for the terminal from the transmission point ;

Receiving a physical downlink control channel (PDCCH) from the transmission point;

The UE is located in a resource region of a physical uplink control channel (PUCCH) for the reception point based on a first control channel element (CCE) index mapped to the PDCCH and the physical information. Deriving a PUCCH resource for; And

And transmitting a PUCCH to the receiving point using the derived PUCCH resource.
The method of claim 1, wherein the physical information,

And a plurality of PUCCH resource candidates are reported in a PUCCH resource region for the terminal in the PUCCH resource region with respect to the reception point.
The method of claim 2,

Downlink control information (DCI) including a PUCCH resource indication field indicating at least one of the plurality of PUCCCH resource candidates is mapped to the PDCCH.
The method of claim 1, wherein the physical information,

Physical cell ID (CID) of the receiving point, capacity of physical HARQ indicator channel (PHICH) of the receiving point, resource offset N (1) at the receiving point ) PUCCH, RHR comprises at least one.
The method of claim 4, wherein

Receiving a physical control format indicator channel (PCFICH) from the receiving point based on the physical cell ID of the receiving point.
The method of claim 5, wherein the deriving the PUCCH resource for the terminal,

And mapping a PUCCH resource at the transmission point derived by the first CCE to a PUCCH resource located in a PUCCH resource region for the terminal among the PUCCH resource regions with respect to the reception point. How information is sent.
The method of claim 1,

The transmitting point is a macro base station (macro eNB), and the receiving point is a remote radio head (RRH) having a lower transmission power than the macro base station, characterized in that the transmission method of the control information.
In the terminal for transmitting the control information,

Receive physical information about a reception point operating as a cooperative set based on a transmission point and a cooperative multipoint transmission / reception scheme for the terminal from the transmission point, receive a PDCCH from the transmission point, and receive the PUCCH. RF unit for transmitting to the point;

And a resource calculation unit for deriving a PUCCH resource for the terminal in the resource region of the PUCCH for the reception point based on the first CCE index mapped to the PDCCH and the physical information.

The RF unit, characterized in that for transmitting the PUCCH to the receiving point using the derived PUCCH resources.
The method of claim 8, wherein the physical information,

And a plurality of PUCCH resource candidates are reported in a PUCCH resource region for the terminal in the PUCCH resource region with respect to the reception point.
The method of claim 9,

And a DCI including a PUCCH resource indication field indicating at least one of the plurality of PUCCCH resource candidates is mapped to the PDCCH.
The method of claim 8, wherein the physical information,

And at least one of a physical cell ID of the reception point, a capacity of a PHICH of the reception point, and a resource offset N (1) PUCCH and RRR at the reception point.
The method of claim 11, wherein the RF unit,

And receiving a PCFICH from the receiving point based on the physical cell ID of the receiving point.
The method of claim 12, wherein the resource calculation unit,

The PUCCH resource is derived by mapping a PUCCH resource at the transmission point derived by the first CCE to a PUCCH resource located in a PUCCH resource area for the UE among the PUCCH resource areas for the reception point. , Terminal.
The method of claim 8,

The transmitting point is a macro base station, and the receiving point is a terminal characterized in that the transmission power is lower than the macro base station RRH.
In the transmission method of control information by a transmission point,

Scheduling a PUCCH resource region for the terminal at a receiving point operating as a cooperative set based on the cooperative multipoint transmission / reception scheme for the terminal;

Transmitting physical information about the reception point for informing the terminal of the PUCCH resource region to the terminal; And

Characterized in that it comprises the step of transmitting a PDCCH to the terminal,

The terminal derives a PUCCH resource for the terminal in the PUCCH resource region based on the first CCE index mapped to the PDCCH and the physical information, and transmits a PUCCH to the receiving point using the derived PUCCH resource. Characterized in that, the control information transmission method.
The method of claim 15,

And scrambling the CRC bit of the PDCCH to a value of a physical control format indicator (CFI) of the reception point.
The method of claim 15, wherein the physical information,

And transmitting a plurality of PUCCH resource candidates in a PUCCH resource region for the terminal.
The method of claim 15, wherein the physical information,

And at least one of a physical cell ID of the receiving point, a capacity of a physical HARQ indication channel (PHICH) of the receiving point, and a resource offset N (1) PUCCH and RRR of the receiving point. Transmission method.
The method of claim 15,

And wherein the transmission point is a macro base station, and the reception point is a remote wireless head having a lower transmission power than the macro base station.