KR101632354B1 - Methods for transmitting and receiving the downlink control information and Apparatuses thereof - Google Patents

Abstract

The present invention relates to a method and an apparatus for transmitting / receiving downlink control information in the case of supporting 256QAM (256-state Quadrature Amplitude Modulation). More particularly, the present invention relates to a modulation and demodulation method for supporting 256QAM in addition to three modulation methods quadrature phase shift keying (QPSK), 16-state Quadrature Amplitude Modulation (16QAM), and 64-state Quadrature Amplitude Modulation and a method and apparatus for transmitting and receiving downlink control information (DCI) including a coding scheme index. According to an aspect of the present invention, there is provided a method of receiving downlink control information, the method comprising: transmitting channel state information including information on a channel quality status measurement to a base station; receiving a modulation and coding scheme (MCS) Receiving from a base station downlink control information including a modulation and coding scheme (MCS) index value selected based on channel state information in a predetermined MCS index table including an index value, And identifying modulation information for the link data.

Description

[0001] The present invention relates to a method for transmitting and receiving downlink control information,

The present invention relates to a method and an apparatus for transmitting / receiving downlink control information in the case of supporting 256QAM (256-state Quadrature Amplitude Modulation). More particularly, the present invention relates to a modulation and demodulation method for supporting 256QAM in addition to the three modulation methods Quadrature Phase Shift Keying (QPSK), 16-state Quadrature Amplitude Modulation (16QAM), and 64-state Quadrature Amplitude Modulation (DCI) including a coding scheme index and an apparatus and method for transmitting and receiving downlink control information (DCI).

Modulation is the conversion of signal (information) intensity, displacement, frequency, phase, etc. into the appropriate waveform form to adapt the signal information to the channel characteristics of the transmission medium. In addition, digital modulation is the conversion of a digital signal (that is, a digital symbol stream) that is to be transmitted in association with one of a variety of possible signals (signal sets) to a signal suitable for channel characteristics. As a typical digital modulation method with good bandwidth efficiency, an M-ary QAM modulation method expressed by 2 ^M QAM such as QPSK (or 4 QAM), 16 QAM, and 64 QAM is used.

Modulation methods used for downlink data transmission in a wireless communication system such as LTE (Long Term Evolution) or LTE-Advanced are QPSK, 16QAM and 64QAM. The base station transmits data to the terminal using this modulation method, and the terminal demodulates the transmitted signal to receive the data.

However, the amount of data transmission / reception between the terminal and the base station is increasing due to explosion of the number of terminals and increase of data usage. There is an increasing demand for a modulation method capable of processing a large amount of data traffic at high speed.

Meanwhile, the base station selects one of the modulation methods considering the downlink channel condition and informs the terminal of the downlink control information (DCI). The UE can receive the data through demodulation according to the data modulation method by checking the received downlink control information.

To do this, the terminal measures the downlink channel condition and transmits information on the measured channel condition to the base station. Also, the base station transmits MCS index information, which is mapped to QPSK, 16QAM, and 64QAM, respectively, to downlink control information. However, a new modulation method is required due to the increase in data traffic and the increase in speed, and a specific method for indicating a new modulation method to a limited downlink control information size is required.

The present invention, which is devised in accordance with the above-described needs, provides a method and apparatus for newly setting an MCS index table when 256QAM is newly defined by a modulation method.

The present invention also provides a method and apparatus for transmitting downlink control information to a terminal using an MCS index table including indication information for 256QAM.

According to another aspect of the present invention, there is provided a method of receiving downlink control information, the method comprising: transmitting channel state information including information indicating a channel quality state to a base station; Receiving, from a base station, downlink control information including a Modulation and Coding Scheme (MCS) index value selected based on channel state information in a preset MCS index table including an MCS (Modulation and Coding Scheme) index value, And determining modulation information for the downlink data based on the index value.

According to another aspect of the present invention, there is provided a method for transmitting downlink control information in a base station, the method comprising: receiving channel state information including information indicating a channel quality state from a terminal; receiving a modulation and coding scheme (MCS) Selecting one modulation and coding scheme (MCS) index value based on the channel state information in a preset MCS index table including the index value and transmitting the downlink control information including the selected MCS index value . ≪ / RTI >

According to another aspect of the present invention, there is provided a terminal for receiving downlink control information, including: a transmitter for transmitting channel state information including information indicating a channel quality state to a base station; an MCS (Modulation and Coding Scheme) A receiving unit for receiving, from a base station, downlink control information including a MCS (Modulation and Coding Scheme) index value selected based on the channel state information in a preset MCS index table including an index value, And a control unit for checking the modulation information on the link data.

According to another aspect of the present invention, there is provided a base station for transmitting downlink control information, the base station including: a receiver for receiving channel state information including information on a channel quality state measurement from a terminal; an MCS (Modulation and Coding Scheme) index corresponding to a 256QAM modulation method; And a transmitter for transmitting downlink control information including a selected MCS index value based on channel state information in a predetermined MCS index table including a value of the MCS index, Base station apparatus.

The present invention provides a method and apparatus for newly setting an MCS index table when 256QAM is newly defined by the modulation method.

In addition, the present invention provides a method and apparatus for transmitting downlink control information to a terminal using an MCS index table including indication information for 256QAM.

1 is a diagram showing a relationship between a modulation order, an MCS and a TBS index.
2 is a diagram illustrating a CQI BLER (Block Error Rate) performance.
3 is a diagram illustrating a conventional CQI index table.
4 is a diagram showing a mapping table between a conventional CQI index table and an MCS and a TBS.
FIG. 5 is a graph showing BLER performance of 64QAM and 256QAM at transmission efficiencies of 5.333, 5.460 and 5.587 in the EPA 3 km / h channel model.
FIG. 6 is a graph showing a required signal-to-noise ratio (SNR) for a BLER of 10% versus a transmission efficiency of 64QAM and 256QAM.
FIG. 7 is a diagram illustrating an example of 64QAM transmission efficiency and Required SNR values in FIG.
FIG. 8 is a diagram illustrating an example of a transmission efficiency and a required SNR value of 256QAM in FIG.
FIG. 9 is a diagram briefly showing each embodiment of the MCS index table according to the present invention.
10 is a signal diagram illustrating operations of a terminal and a base station according to an embodiment of the present invention.
11 is a diagram illustrating an example of an MCS index table according to the first embodiment of the present invention.
12 is a view showing another example of the MCS index table according to the first embodiment of the present invention.
13 is a diagram illustrating an example of an MCS index table according to the second embodiment of the present invention.
FIG. 14 is a diagram showing another example of the MCS index table according to the second embodiment of the present invention.
15 is a diagram illustrating an example of an MCS index table according to the third embodiment of the present invention.
16 is a diagram showing another example of an MCS index table according to the third embodiment of the present invention.
17 is a diagram illustrating an example of an MCS index table according to the fourth embodiment of the present invention.
18 is a view showing another example of the MCS index table according to the fourth embodiment of the present invention.
19 is a diagram showing a TBS table in which a conventional VoIP TBS is defined.
20 is a diagram summarizing a case where a specific VoIP TBS is included in each TBS index.
FIG. 21 is a diagram illustrating an example of an MCS index table according to the fifth embodiment of the present invention.
22 is a diagram illustrating an example of a target SNR for defining an MCS index table according to the fifth embodiment of the present invention.
23 is a diagram illustrating an example of a code rate R according to the fifth embodiment of the present invention.
24 is a view showing another example of a coding rate according to the fifth embodiment of the present invention.
25 is a view showing another example of a target SNR for defining an MCS index table according to the fifth embodiment of the present invention.
26 is a view showing another example of a code rate R according to the fifth embodiment of the present invention.
FIG. 27 is a diagram illustrating another example of the coding rate according to the fifth embodiment of the present invention.
28 is a diagram illustrating an example of a coding rate according to the sixth embodiment of the present invention.
29 is a view showing another example of a coding rate according to the sixth embodiment of the present invention.
30 is a diagram illustrating an example of an MCS index table according to a seventh embodiment of the present invention.
31 is a diagram illustrating an example of a coding rate according to a tenth embodiment of the present invention.
32 is a diagram illustrating an example of an MCS index table according to a tenth embodiment of the present invention.
33 is a view showing another example of the MCS index table according to the tenth embodiment of the present invention.
34 is a diagram illustrating an example of a coding rate according to an eleventh embodiment of the present invention.
35 is a view showing another example of a coding rate according to the eleventh embodiment of the present invention.
36 is a diagram illustrating an example of an MCS index table according to an eleventh embodiment of the present invention.
37 is a diagram illustrating another example of a coding rate according to the eleventh embodiment of the present invention.
38 is a diagram showing another example of the MCS index table according to the eleventh embodiment of the present invention.
FIG. 39 is a diagram for explaining operations of a terminal according to another embodiment of the present invention.
40 is a view for explaining the operation of a base station according to another embodiment of the present invention.
41 is a diagram illustrating a configuration of a terminal according to another embodiment of the present invention.
FIG. 42 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

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

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

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

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

Therefore, a base station is collectively referred to as a base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Modulation is the conversion of signal (information) intensity, displacement, frequency, phase, etc. into an appropriate waveform type to match the signal information to the channel characteristics of the transmission medium. In addition, digital modulation is the conversion of a digital signal (that is, a digital symbol stream) to be transmitted in correspondence with one of a variety of possible signals (signal sets) to a signal suited to channel characteristics. As a typical digital modulation method with good bandwidth efficiency, an M-ary QAM modulation method expressed by 2 ^M QAM such as QPSK (or 4 QAM), 16 QAM, 64 QAM and 256 QAM is used. Where M represents the number of digital symbols modulated in a modulation order at one time and Modulation orders of QPSK, 16QAM, 64QAM and 256QAM are 2, 4, 6, and 8, respectively.

Modulation methods used for downlink data transmission in 3GPP LTE are QPSK, 16QAM and 64QAM. The base station selects one of the three modulation methods in consideration of the downlink channel condition and informs the terminal of the downlink control information (Downlink Control Information, DCI).

1 is a diagram showing a relationship between a modulation order, an MCS and a TBS index.

The MCS (Modulation and Coding Scheme) index of 5-bits among the DCIs described above informs the UE of three modulation methods as shown in FIG. In FIG. 1, MCS indexes 0 to 28 are used for initial transmission of HARQ (Hybrid Automatic Repeat reQuest), and 29 to 31 are used for HARQ retransmission.

More specifically, the MCS indexes 0 to 9 mean that the QPSK modulation method is used for downlink data transmission, the 16QAM modulation method for the 10th to 16th steps, and the 64QAM modulation method for the 17th to 28th steps are the downlink data transmission methods . ≪ / RTI >

There are also a plurality of MCS indexes for the same modulation method, and each MCS index indicates that data can be transmitted using codewords having different coding rates. If the channel condition is good, the base station increases the bandwidth efficiency by using a high MCS index and performs a low burst transmission using a low MCS index to overcome the channel condition when the channel condition is poor. The method of adjusting the MCS according to the channel condition is called link adaptation. In other words, link adaptation means adjusting the MCS to compensate for time-varying radio channel characteristics to maximize system throughput.

If MCS indexes 0 to 28 are used for HARQ initial transmission, the MCS indexes 29, 30 and 31 are used to distinguish the modulation method used for HARQ retransmission. Therefore, MCS index 29 indicates that QPSK modulation is used for 30 times 16QAM modulation and 31 times 64QAM modulation is used for HARQ retransmission.

Referring to FIG. 1, a transport block size (TBS) index I _TBS corresponds to each MCS index I _MCS . In 3GPP TS 36.213 document, considering that the size of transmission resources can be allocated to terminals from 1 PRB pair (physical resource block pair) to 110 PRB pairs, 110 bits of information bits to be transmitted per TBS index _TBS Is defined.

FIG. 2 is a diagram illustrating a CQI BLER (Block Error Rate) performance, and FIG. 3 is a diagram illustrating a conventional CQI index table.

In order for the base station to perform link adaptation according to the channel condition of the UE, the UE must feedback the channel condition to the BS. The channel state information that the UE feeds back to the base station is called CSI (Channel State Information). The channel state information (CSI) is composed of PMI (Pre-coding Matrix Indicator), RI (Rank Indicator) and CQI (Channel Quality Indicator). Here, PMI and RI are channel state information related to a Multiple-Input Multiple-Output (MIMO) transmission, and the CQI is a modulation method, a code rate * 1024, Efficiency (Efficiency = modulation order * coding rate). The UE feeds back a CQI index having a high transmission efficiency when the channel condition is good and a low CQI index to the base station if the channel condition is bad.

The size of the conventional CQI feedback information is 4 bits, indicating 16 transmission efficiencies. FIG. 2 is a graph illustrating the performance of the CQI of FIG. 3 in a test environment in which a single transmit antenna and two receive antennas are considered in an AWGN channel environment; a required SNR value satisfying a block error rate (BLER) Respectively. In FIG. 2, the required CQI of the conventional CQI ranges from about -10 dB to 17 dB for a required SNR of 10%, and each CQI index has a signal-to-noise ratio (SNR) And the transmission efficiency is set to have an interval.

 4 is a diagram showing a mapping table between a conventional CQI index table and an MCS and a TBS.

The BS checks the CQI received from the MS, and determines a resource allocation amount and an MCS to be used for transmission based on the received CQI. At this time, the MCS of FIG. 1 and the CQI of FIG. 3 have the relationship shown in FIG.

4, 6, 7, 8, 11, 13, 15, 18, 20, 22, 24, 26 and 28 are CQI indices 2, 3, 4, 5, 6, 7 , 8, 9, 10, 11, 12, 13, 14 and 15 can be set to have the same transmission efficiency. In addition, an MCS index having a transmission efficiency corresponding to the intermediate transmission efficiency supported by two CQI indexes is set between two consecutive CQI indexes.

However, the MCS indexes 9 and 10 in which the modulation order is changed from QPSK to 16QAM are set to have the same transmission efficiency, and the MCS indexes 16 and 17 in which the modulation order is changed from 16QAM to 64QAM are set to have the same transmission efficiency. In addition, since the MCS indexes having different modulation orders are set to have the same TBS index, the same TBS is transmitted to the same amount of transmission resources.

The BS checks the channel status through the CQI received from the MS, and selects a size of a transmission resource to be allocated to the MS and an MCS to be used for the corresponding transmission resource with reference to the CQI. At this time, determining the coding rate of the MCS is equivalent to determining the TBS, which is the size of the information bits to be transmitted to the corresponding transmission resource.

In the present invention, a method and apparatus for transmitting and receiving channel state information transmitted by a mobile station to a base station in the case where 256QAM is added to three modulation methods QPSK, 16QAM, and 64QAM that have been used conventionally to increase transmission traffic and speed . More specifically, a method and an apparatus for setting a CQI included in channel state information are proposed.

Conventionally, since there is no CQI index indicating 256QAM, in order to transmit data using 256QAM, it is necessary to define a CQI index corresponding to the modulation method of 256QAM. That is, when 64QAM and 256QAM are used for the same transmission efficiency, there is a need to define a CQI using 256QAM from a transmission efficiency in which the BLER performance of 256QAM is equal to or better than 64QAM.

FIG. 5 is a graph showing BLER performance of 64QAM and 256QAM at transmission efficiencies of 5.333, 5.460 and 5.587 in an EPA (Extended Pedestrian A model) 3 km / h channel model.

Referring to FIG. 5, it can be seen that the BLER performance of 64QAM and 256QAM is the same at a transmission efficiency of 5.587. Therefore, considering that the maximum transmission efficiency is 5.5547 in the conventional CQI index table of FIG. 3, a new CQI using 256QAM as a modulation method is set to support a transmission efficiency that is equal to or greater than the conventional transmission efficiency of 5.5547.

 In order to set a new CQI supporting 256QAM while maintaining 4 bits of the conventional CQI feedback information size, it is necessary to remove some of the conventional CQI indexes and define a new transmission efficiency.

Considering that in one embodiment of the present invention, in I _TBS 0 in the conventional TBS table 16 by the TBS to support the VoIP service is set, CQI index 0 from I _TBS The CQI index 10 corresponding to 16 can be excluded from the removal target to define a new CQI. In other words, in order not to affect the VoIP service, it is possible to define the transmission efficiency to support 64QAM and 256QAM in five CQI indices from CQI index 11 to 15 by reusing CQI indexes 0 to 10 which were conventionally used.

As another example, the conventional CQI indexes 0 to 10 may be newly defined, and the CQI indexes 11 to 15 for 64QAM and 256QAM may be newly defined.

FIG. 6 is a graph showing a required signal-to-noise ratio (SNR) for a BLER of 10% versus a transmission efficiency of 64QAM and 256QAM.

FIG. 7 is a diagram illustrating an example of 64QAM transmission efficiency and Required SNR values in FIG.

FIG. 8 is a diagram illustrating an example of a transmission efficiency and a required SNR value of 256QAM in FIG.

Referring to FIG. 7, the transmission efficiency and the required SNR value of the 64QAM shown in FIG. 6 are shown. Referring to FIG. 8, the transmission efficiency and the required SNR value of 256QAM are shown.

In the present invention, in order to calculate the estimated required SNR (Estimation Req. SNR) with respect to the transmission efficiency in FIGS. 6 to 8, the following Equation 1 is used for the transmission efficiency using 64QAM and the transmission efficiency using 256QAM The following equation (2) is used. In the following equations (1) and (2), a value of R = code rate * 1024 is shown. In the present specification, R is expressed as a code rate.

6, 7 and 8, the required SNR values estimated using Equations 1 and 2 described above do not substantially differ from the measured values in the experimental environment described above. That is, in Fig. 7 and Fig. 8, Esti.Req. SNR - Eval. Req. It can be confirmed that the difference between the SNR values is very small.

In the present invention, a method and apparatus for transmitting and receiving downlink control information including a new MCS index will be described based on the above description.

The MCS index table of FIG. 1 shows 32 modulation indexes, 29 MCS indexes indicate transmission efficiency, and 3 MCS indexes are used for HARQ (Hybrid Automatic Repeat Request) retransmission. Also, among the 29 MCS indexes, the MCS indices 9 and 10 are set to use QPSK and 16QAM for the same transmission efficiency, respectively, and the MCS indices 16 and 17 are set to use 16QAM and 64QAM for the same transmission efficiency, respectively. Thus, two MCS indices are overlapped for each of the two transmission efficiencies. In addition, in FIG. 4, the transmission efficiency defined by the CQI is included in the MCS index table, and an MCS index table is configured to always support one additional transmission efficiency between adjacent CQIs. In addition, MCS index 0 is equal to CQI index 2, and MCS index 28 is set equal to CQI 15.

FIG. 9 is a diagram briefly showing each embodiment of the MCS index table according to the present invention.

In order to support 256QAM, an MCS index table has to be newly defined, and it has various numbers of constituent MCS index tables as shown in FIG. 9 below. The MCS index used for the HARQ retransmission can be considered to be three or four. Accordingly, the number of MCS indexes used for HARQ initial transmission is set to 29 or 28. In consideration of the fact that two MCS indexes can be superimposed on the same transmission efficiency, it is also possible to design two MCS indexes so as not to overlap one transmission efficiency, or to design two MCS indexes for only two transmission efficiencies index, or the MCS index using 64QAM and 256QAM may be added so that two MCS indexes are overlapped for three transmission efficiencies.

In order to maintain the number of transmission efficiencies defined between neighboring CQIs in the same manner as the conventional method, the MCS index for HARQ retransmission can be defined to be 3, and the number of transmission efficiencies to be overlapped with MCS index can be defined to be 2 in the present invention.

In the conventional TBS index table, from I _TBS 0 to 16, considering that TBS for supporting VoIP service is set, MCS index 0 to I _TBS 16 is recycled up to MCS index 18, and transmission efficiency for MCS supporting 64QAM and 256QAM is defined to 10 MCS indexes from MCS index 19 to 28. [

In addition, since the number of transmission efficiencies in which the MCS index is overlapped is two, the MCS indexes supporting 64QAM and 256QAM can be defined so as not to overlap with the same transmission efficiency.

10 is a signal diagram illustrating operations of a terminal and a base station according to an embodiment of the present invention.

A method for receiving downlink control information according to an exemplary embodiment of the present invention includes: transmitting channel state information including information on a channel quality status measurement to a base station; and performing MCS receiving a downlink control information including a modulation and coding scheme (MCS) index value selected based on channel state information from a base station in a predetermined MCS index table including an index value and a coding scheme index, And determining modulation information for the downlink data based on the modulation information.

A method of transmitting downlink control information according to an exemplary embodiment of the present invention includes receiving channel state information including information indicating a channel quality state from a terminal, Selecting one modulation and coding scheme (MCS) index value based on the channel state information in a predetermined MCS index table including a modulation and coding scheme index value, and transmitting the downlink control information including the selected MCS index value To the mobile station.

Referring to FIG. 10, a terminal 1010 of the present invention measures a channel quality of a downlink channel. For example, the quality of the downlink channel can be measured based on the reference signal transmitted from the base station 1000, and the channel quality indication information corresponding to the quality can be selected. The terminal 1010 transmits the selected channel quality indicator (CQI) to the base station 1000 in step S 1010, including channel state information (CSI).

The base station 1000 can receive channel state information from the UE 1010 and check the CQI index value included in the channel state information. Thereafter, one MCS (Modulation and Coding Scheme) index value may be selected from a preset MCS index table including an MCS (Modulation and Coding Scheme) index value corresponding to the 256QAM modulation method based on the identified CQI index value S1020). The MCS index table including the MCS index values corresponding to the 256QAM modulation method described above can be set by various embodiments described below.

Then, the base station 1000 may transmit downlink control information including the selected MCS index value to the terminal 1010 (S1030). The UE 1010 receives the downlink control information from the Node B and can check the modulation information for the downlink data according to the selected MCS index value (S1040).

The base station 1000 modulates downlink data according to the modulation method included in the downlink control information and transmits the downlink data to the terminal 1010. The terminal 1010 modulates the downlink data according to the MCS index value And demodulate the downlink data.

In selecting the MCS index value, the base station 1000 of the present invention may select an MCS index value corresponding to a CQI index value in an MCS index table including 256QAM instead of the conventional MCS index table. Therefore, there is a need to newly set an MCS index table that has not existed conventionally. In order to efficiently process traffic and increase the transmission speed, it is very important to efficiently set an MCS index table including an MCS index value for 256QAM .

Therefore, various embodiments of the present invention will be described below with reference to a concrete method of setting an MCS index table including an MCS index value of 256QAM referred to by a base station.

1st Example

The transmission efficiency for 10 new MCS indexes added based on the conventional MCS index 18 is defined. At this time, in detail method 1, the transmission efficiency can be set so that the difference between the required SNR for the BLER 10% of all the MCS index and the required SNR of the adjacent MCS index is constant from the MCS index 18.

First, when the code rate to be used for the maximum transmission efficiency is represented by R in the new MCS, the maximum value of R can be defined as 948, which is the same as the conventional maximum transmission efficiency of the CQI.

In this case, the Required SNR of the MCS index 18 may be used as the minimum SNR, and the Required SNR calculated by Equation 2 as R = 948 may be used as the maximum SNR. Therefore, the SNR interval between adjacent MCS indexes can be calculated as shown in Equation 3 below.

The target SNR is defined using the SNR interval value calculated according to Equation (3).

11 is a diagram illustrating an example of an MCS index table according to the first embodiment of the present invention.

In the embodiment of the MCS proposed in the present invention, R is determined using Equations (1) and (2) so that the difference in Required SNR between neighboring MCSs is as equal as possible. A new MCS index table constructed in this manner is shown in FIG.

12 is a view showing another example of the MCS index table according to the first embodiment of the present invention.

In the detailed method 2 of the present invention, the maximum value of R to be used for the maximum transmission efficiency of the new MCS may be defined as 952, considering the maximum code rate 0.93? 952/1024 used in setting the conventional TBS. R is determined using Equations (1) and (2) so that the difference in Required SNR between neighboring MCSs is as equal as possible. A new MCS index table constructed in this manner is shown in FIG.

For the new MCS index, 10 TBS table indexes must be added to support transmission efficiency. Also, it can be seen that the MCS indices 18, 20, 22, 24, 26 and 28 can be set to the CQI index 10 to 15 as in the prior art.

Second Example

13 is a diagram illustrating an example of an MCS index table according to the second embodiment of the present invention.

In the second embodiment of the MCS proposed in the present invention, since the MCS indexes 18, 20, 22, 24, 26 and 28 in the first embodiment can be set to CQI index 10 to 15 as in the conventional art, , 21, 23, 25 and 27 can be set by rounding the average value of two R values of adjacent CQIs so that the difference in transmission efficiency between adjacent MCS indexes becomes equal intervals.

A new MCS index table configured by using the CQI set in FIG. 11 in this manner is shown in FIG.

13, the effective R value for 256QAM is calculated from the transmission efficiency of CQI 13, and the R value and the average value of CQI 14 are rounded off, since the modulation methods of two adjacent CQIs are different from each other.

FIG. 14 is a diagram showing another example of the MCS index table according to the second embodiment of the present invention.

In the same way, a new MCS index table constructed using the CQI set in Fig. 12 is shown in Fig.

In FIG. 14, the effective R value for 256QAM is calculated from the transmission efficiency of CQI 13 because the modulation method of two adjacent CQIs is different from that of MCS index 25, and the R value and average value of CQI 14 are rounded off.

For the new MCS index of the second embodiment described above, 10 TBS table indexes for supporting transmission efficiency should be added.

Third Example

15 is a diagram illustrating an example of an MCS index table according to the third embodiment of the present invention.

The transmission efficiency for five new CQIs added based on the conventional CQI index 10 is first defined. At this time, in the third embodiment, the MCS of the 64QAM which is conventionally used is reused. In FIG. 4, Esti. For 10% of BLER between adjacent CQI indexes including CQI index 10 (or MCS index 18) among MCS indexes 18 to 28 used as a conventional 64QAM. Req. The MCS index is first selected so that the difference in SNR (estimated required SNR) value is at most equally spaced. The MCS thus selected is the MCS indices 18, 21, 24 and 27 of FIG. It can be confirmed that the interval between MCS indexes of two adjacent MCSs is constant at 3. In this way, the four new MCS indexes are 18, 20, 22, 24.

Also, a new MCS can be defined by allocating one additional transmission efficiency between adjacent CQIs. In this case, R is determined using Equations (1) and (2) so that the difference in Required SNR between neighboring MCS indexes is maximally equal. In this way, the new MCS index defines 19, 21, and 23.

The remaining four MCS indices 25 to 28 define the transmission efficiency using 256QAM. As described in the first embodiment, the required SNR for the conventional MCS index 27 (or the MCS index 24 corresponding to the maximum transmission efficiency using the 64QAM among the new MCS defined above) is used as the minimum SNR, 2 to R = 948 can be used as the maximum SNR. Therefore, the transmission efficiency using 256QAM can be defined in the MCS indices 25 to 28 in the same manner as in the first embodiment described above so that the difference in Required SNR between neighboring MCSs is as equal as possible.

The transmission efficiency of a new MCS index defined in this manner is shown in FIG.

16 is a diagram showing another example of an MCS index table according to the third embodiment of the present invention.

15, in order to define the transmission efficiency using 256QAM in the MCS indices 25 to 28, considering the maximum code rate 0.93? 952/1024 used in setting the conventional TBS, R The maximum value of 952 may be used.

In addition, the required SNR of the conventional MCS index 27 (or the MCS index 24 corresponding to the maximum transmission efficiency using the 64QAM among the new MCS defined above) is used as the minimum SNR, and the Required SNR calculated by R = 952 in Equation Can be used as the maximum SNR.

Therefore, the transmission efficiency using 256QAM can be defined in four MCS indexes 25 to 28 as in the first embodiment so that the difference in Required SNR between adjacent MCSs is as equal as possible.

The transmission efficiency of the new MCS index defined in this manner is shown in FIG.

For the new MCS index according to the third embodiment, seven TBS table indexes for supporting transmission efficiency should be added.

Fourth Example

17 is a diagram illustrating an example of an MCS index table according to the fourth embodiment of the present invention.

Since the MCS indices 18, 20, 22, 24, 26 and 28 in the first embodiment can be set to the CQI index 10 to 15 as in the conventional example, the MCS indices 19, 21, 23, 25, and 27 are set by rounding the average value of the two R values of the adjacent CQI so that the difference in transmission efficiency between adjacent MCS indexes becomes equal intervals.

A new MCS index table configured using the CQI set in Fig. 15 in this way is shown in Fig. 17

In FIG. 17, since the modulation methods of two adjacent CQIs are different from each other, the effective R value for 256QAM is calculated from the transmission efficiency of MCS index 24, and the R value and average of MCS 26 are rounded off.

18 is a view showing another example of the MCS index table according to the fourth embodiment of the present invention.

In the same way, a new MCS index table configured using the CQI set in Fig. 16 is shown in Fig.

18, the effective R value for 256QAM is calculated from the transmission efficiency of the MCS index 24, and the R value of the MCS index 26 is averaged and rounded off.

For the new MCS index according to the fourth embodiment, seven TBS table indexes for supporting transmission efficiency should be added.

The first to fourth embodiments described above are constructed in such a way as not to affect the conventional VoIP TBS. In this case, the required SNR difference of the adjacent MCS indexes in the low SNR interval in which QPSK and 16QAM are used is relatively small, but the required SNR difference in the adjacent MCS index is relatively large in the high SNR interval including 64QAM and 256QAM .

19 is a diagram showing a TBS table in which a conventional VoIP TBS is defined. FIG. 19 shows an excerpt of a portion in which a VoIP TBS is defined in a conventional TBS table.

20 is a diagram summarizing a case where a specific VoIP TBS is included in each TBS index. The VoIP TBS is summarized in FIG. 19, and the presence or absence of each TBS index I _{TBS for} each VoIP TBS 144, 176, 208, 224, 256 and 328 bits is shown in FIG.

Referring to FIG. 20, it can be seen that the TBS index I _TBS in which all the VoIP TBSs exist is 1, and the TBS index I _TBS in which there are five VoIP TBSs in the six VoIP _TBSs is 0 and 2, respectively.

Fifth Example

FIG. 21 is a diagram illustrating an example of an MCS index table according to the fifth embodiment of the present invention.

In the fifth embodiment, the conventional MCS index 0, 1, 2 is used as a new MCS entry so as to reuse the TBS index I _TBS 0, 1, 2 which includes a relatively large number of VoIP TBSs as shown in FIG. Also, the conventional MCS indexes 0, 2, 4, 6, 8 and 11 corresponding to the conventional CQI indexes 2, 3, 4, 5, 6 and 7 are updated so that the difference between the required SNRs of adjacent MCS indexes has similar values. Used as an MCS entry. Also, among the conventional MCS indexes 12 to 28, the MCS index 17 corresponding to 64QAM for the transmission efficiency in which 16QAM and 64QAM are overlapped, and the BLER performance equal to 256QAM for the same transmission efficiency as in FIG. 5 in the conventional MCS index Except for MCS index 28, the remaining MCS entries are used as new MCS entries. A new MCS index table constructed in this manner is shown in FIG.

Since 22 of the 29 conventional MCS indexes are used as a new MCS index, the transmission efficiency for 7 MCS entries to support 256QAM should be defined. MCS indices 29, 30 and 31 can be used to distinguish the modulation scheme used for HARQ retransmission.

Hereinafter, a method of defining R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , R ₂₆ , R _27, and R ₂₈ representing the transmission efficiency for the MCS indexes 22 to 28 of FIG. 21 will be described.

22 is a diagram illustrating an example of a target SNR for defining an MCS index table according to the fifth embodiment of the present invention.

First, R ₂₂ , R ₂₄ , R ₂₆ , and R ₂₈ for the MCS indices 22 24, 26, and 28 usable as the CQI are defined first. It is possible to use the Required SNR of MCS index 20 of FIG. 21 as the minimum SNR and the Required SNR calculated as R = 948 of Equation 2 as the maximum SNR. The SNR interval calculated using the above-described minimum SNR and maximum SNR is calculated as shown in Equation (4).

The target SNR is defined using the SNR interval value calculated by the above-described method, as shown in FIG.

23 is a diagram illustrating an example of a code rate R according to the fifth embodiment of the present invention.

Using the Required SNR of FIG. 22 and Equation (2), the R value is determined such that the difference in Required SNR between adjacent MCS indexes is maximally equally spaced. The R value satisfying the target SNR in FIG. 22 is obtained as shown in FIG.

24 is a view showing another example of a coding rate according to the fifth embodiment of the present invention.

₂₃ , the R value is determined such that the difference in Required SNRs between neighboring MCS indexes is as equal as possible for R ₂₃ , R ₂₅ , and R _{27 as shown} in FIG.

25 is a view showing another example of a target SNR for defining an MCS index table according to the fifth embodiment of the present invention.

As another embodiment of the MCS index suggested in the present invention, considering the maximum code rate 0.93? 952/1024 used in setting the conventional TBS, the maximum value of R to be used for the maximum transmission efficiency of the new MCS index can be defined as 952 have. The required SNR of MCS index 20 in FIG. 21 is used as the minimum SNR, and the required SNR calculated by R = 952 in Equation 2 can be used as the maximum SNR. Target SNRs of R ₂₂ , R ₂₄ , R ₂₆ , and R ₂₈ for MCS indices 22, 24, 26, and 28 usable as CQIs are defined as shown in FIG.

26 is a view showing another example of a code rate R according to the fifth embodiment of the present invention.

The R value is determined such that the difference in Required SNR between neighboring MCS indexes is maximally equally spaced by using the Required SNR of FIG. 25 and Equation (2). The R value satisfying the target SNR in Fig. 25 is obtained as shown in Fig.

FIG. 27 is a diagram illustrating another example of the coding rate according to the fifth embodiment of the present invention.

In FIG. 26, the R value is determined such that the difference in Required SNR between adjacent MCS indexes is maximally equally spaced for R ₂₃ , R ₂₅ , and R _{27 as shown} in FIG.

6th Example

28 is a diagram illustrating an example of a coding rate according to the sixth embodiment of the present invention.

The sixth embodiment is the transmission efficiency between the MCS index contiguous with respect to R _23, R _25, R ₂₇ in the Figure 23 or Figure 26 of the present invention such that as much as possible equal _{intervals, R 23, R 25, R} 27 The average value of R values of two adjacent MCS indexes is rounded up and set. For example, R ₂₃ is determined by rounding the value of (R ₂₂ + R ₂₄ ) / 2. Referring to FIG. 20, R value is defined by this method as shown in FIG.

29 is a view showing another example of a coding rate according to the sixth embodiment of the present invention.

Referring to FIG. 26, if the R value is defined such that the transmission efficiency between adjacent MCS indexes is maximized by the method of the sixth embodiment, as shown in FIG.

Seventh Example

In the above-described fifth and sixth embodiments, MCS indexes 29, 30 and 31 are partially reused as shown in FIG. 21 on the assumption that the MCS indexes 29, 30 and 31 are used to distinguish the modulation method used for HARQ retransmission.

On the other hand, it can be assumed that QPSK, 16QAM, 64QAM and 256QAM are used to distinguish modulation methods used for HARQ retransmission using MCS index, respectively. That is, the MCS index for HARQ retransmission can be set to four.

30 is a diagram illustrating an example of an MCS index table according to a seventh embodiment of the present invention.

In order to use as many VoIP TBSs as possible, the conventional MCS index 1 may be removed and four MCS entries may be used for HARQ retransmission in order to use the maximum number of VoIP TBSs with a difference in required SNRs between neighboring MCS indexes as much as possible. Therefore, in the present embodiment, a conventional MCS index can be partially reused as shown in FIG. R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , R ₂₆ , R ₂₇ and R ₂₈ defined in the above-described fifth and sixth embodiments are R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ , R _26, and R ₂₇ .

Eighth Example

Meanwhile, the MCS index supporting the maximum transmission efficiency among the MCS indexes added for 256QAM as described above is defined as R = 948 in FIGS. 11, 13, 15, 17, 24 and 28.

In the eighth embodiment of the present invention, the R value for the MCS index 28 is changed from 948 to 952 in FIGS. 11, 13, 15, 17, 24, Can be used.

Since the eighth embodiment defines changing the R value of the MCS index 28 in Figs. 24 and 28 applied in the seventh embodiment from 948 to 952, the MCS indices 22 to 27 of Fig. 30 of the seventh embodiment are maintained , And the R value for the MCS index 27 is changed from 948 to 952.

Among the MCS indexes added for 256QAM, the MCS index supporting the maximum transmission efficiency is defined as R value of 952 in FIGS. 12, 14, 16, 18, 27 and 29.

Therefore, with the other method of the eighth embodiment, the R value for the MCS index 28 is changed from 952 to 948 while maintaining the MCS indices 22 to 27 in Figs. 12, 14, 16, 18, Can be used interchangeably.

The eighth embodiment defines changing the R value of the MCS index 28 in Figs. 27 and 29 applied in the seventh embodiment from 952 to 948, so that the MCS indices 21 to 26 of Fig. 30 of the seventh embodiment are maintained , And the R value for the MCS index 27 is changed from 952 to 948.

9th Example

In the ninth embodiment, the MCS index with the lowest transmission efficiency among the MCS indexes using 256QAM is set to have the same transmission efficiency as that of the MCS index with the highest transmission efficiency. In the ninth embodiment, 24 and 28, the R value for the MCS index 22 can be changed from 710 to 711 while maintaining the MCS indices 23 to 28 as they are.

Since the MCS index 22 of FIGS. 24 and 28 is changed from 710 to 711 in the ninth embodiment, the MCS indices 22 to 27 of the seventh embodiment are maintained as they are, and the R value ≪ / RTI > from 710 to 711.

Article 10 Example

31 is a diagram illustrating an example of a coding rate according to a tenth embodiment of the present invention.

The value 710 of R _{22 shown in} FIG. 23 is changed to 711 as in the ninth embodiment, and R ₂₃ , R ₂₅ , and R ₂₇ are obtained by an average of two adjacent MCS indexes as shown in FIG.

32 is a diagram illustrating an example of an MCS index table according to a tenth embodiment of the present invention.

However, even if it is the R ₂₅ value which is not a natural number generation 31, shown in Figure 32 by defining the MCS index table as the transport efficiency and the modulation method.

33 is a view showing another example of the MCS index table according to the tenth embodiment of the present invention.

As another example, when four MCS entries are used for HARQ retransmission as shown in FIG. 30 of the seventh embodiment, a new MCS index table is shown in FIG.

Eleventh Example

34 is a diagram illustrating an example of a coding rate according to an eleventh embodiment of the present invention. 35 is a view showing another example of a coding rate according to the eleventh embodiment of the present invention.

When the code rate and the transmission efficiency used in the CQI are the same as those in FIG. 34, FIG. 35 shows R ₂₃ , R ₂₅ , and R ₂₇ as the average of two adjacent MCS indexes.

36 is a diagram illustrating an example of an MCS index table according to an eleventh embodiment of the present invention.

In FIG. 35, since the value of R ₂₇ is not a natural number, the MCS index table is defined as a transmission efficiency and a modulation method as shown in FIG.

37 is a diagram illustrating another example of a coding rate according to the eleventh embodiment of the present invention.

When four MCS entries are used for HARQ retransmission as shown in FIG. 30 of the seventh embodiment, the coding rate for the MCS index in FIG. 35 is as shown in FIG. That is, R ₂₂ to R ₂₈ in FIG. 30 are determined to be R ₂₁ to R _{27 in} FIG.

38 is a diagram showing another example of the MCS index table according to the eleventh embodiment of the present invention.

When four MCS entries are used for HARQ retransmission as shown in FIG. 30 of the seventh embodiment, a new MCS index table using the coding rate of FIG. 37 is shown in FIG.

As described above, the base station can select the MCS index value using the newly set MCS index table according to the first to eleventh embodiments. Hereinafter, the operation of the terminal and the base station when the MCS index table according to the eleventh embodiment described above with reference to FIG. 39 and FIG. 40 is set will be described. Even in the case of the first to tenth embodiments, only the method of setting the MCS index table is different, and the operation of the terminal and the base station described below can be performed in the same manner.

FIG. 39 is a diagram for explaining operations of a terminal according to another embodiment of the present invention.

A method for receiving downlink control information in a mobile station includes transmitting channel state information including information indicating a channel quality state to a base station and transmitting the channel state information including a Modulation and Coding Scheme Index (MCS) corresponding to a 256QAM modulation method From a base station, downlink control information including a modulation and coding scheme (MCS) index value selected based on channel state information in a predetermined MCS index table including a value of a downlink data And checking the modulation information for the received signal.

Referring to FIG. 39, the UE includes a step of transmitting channel state information including information indicating a channel quality state to a base station (S3900). The channel state information may include information on a result of measuring a channel quality of a downlink channel based on a reference signal. For example, the UE receives a reference signal for channel measurement from the BS and analyzes the received reference signal to measure the channel quality of the downlink channel. Then, the UE selects a preset CQI index value according to the channel quality result, and transmits the selected CQI index value to the base station by including it in the channel status information.

The UE transmits downlink control information including a MCS (Modulation and Coding Scheme) index value selected based on channel state information in a preset MCS index table including an MCS (Modulation and Coding Scheme) index value corresponding to the 256QAM modulation method From the base station (S3910). The terminal receives downlink control information (DCI) from the base station. The downlink control information received by the UE includes an MCS index value indicating a modulation method, and the MCS index value is a value selected by the BS based on the CQI index value of the UE. The MCS index value is a value selected from the MCS index table stored in advance in the UE and the Node B, and includes information on the modulation method of the downlink data. That is, as described above, information on the modulation order and information on the transmission efficiency can be included.

The present invention relates to the setting of an MCS index value that can be included in downlink control information when a 256QAM with a modulation order of 8 is introduced, and the terminal selects a downlink control signal from the MCS index table including an MCS index value corresponding to 256QAM, Control information can be received.

The MCS index table can be set according to the first to eleventh embodiments as described above. In Fig. 39, the setting of the MCS index table according to the eleventh embodiment will be described.

The MCS index table of the present invention includes five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, It may contain eight MCS index values. That is, a total of 28 MCS index values for HARQ initial transmission can be allocated, and the number of MCS index values according to each modulation order can be allocated as above.

Also, the MCS index table of the present invention may include MCS index values for four HARQ retransmissions and MCS index values for 28 HARQ initial transmissions. For example, as described in the first to eleventh embodiments, in the case of HARQ retransmission, one MCS index value may be assigned to each of the modulation orders 2, 4, 6, and 8, and an MCS index for HARQ initial transmission The index value can be assigned 28.

In addition, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6. For example, as shown in FIG. 4, in the MCS index table in which the maximum value of the modulation order is 6, the maximum transmission efficiency is set to 5.5547. Therefore, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to a transmission efficiency of 5.5547. That is, in the case of the MCS index 21 shown in FIG. 38, the transmission efficiency is set to 5.5547.

One of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to have the same code rate as the code rate with the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6. [ For example, as shown in FIG. 4, in the MCS index table in which the maximum value of the modulation order is 6, the code rate R having the maximum transmission efficiency is set to 948. [ Therefore, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to the code rate 948. [ That is, as shown in FIG. 37, the code rate of the MCS index 27 may be set to 948. FIG.

The MCS index table of the present invention can be set such that each of the MCS index values corresponding to the 256QAM modulation method has the coding rate of FIG. 37, the coding rate of the MCS index value corresponding to the 256QAM modulation method is 711 for the MCS index 21, 754 for the MCS index 22, 797 for the MCS index 23, 841 for the MCS index 24, 885 for the MCS index 25, 885 for the MCS index 25, The index 26 may be set to 916.5 and the MCS index 27 to 948.

In the MCS index table of the present invention, the MCS index value corresponding to the 256QAM modulation method can be set to have the transmission efficiency shown in FIG. As shown in FIG. 38, the MCS index 21 is 5.5547, the MCS index 22 is 5.8906, the MCS index 23 is 6.2266, the MCS index 24 is 6.5703, the MCS index 25 is 6.9141, the MCS index 25 is 6.9141, The index 26 can be set to 7.1602 and the MCS index 27 can be set to have a transmission efficiency of 7.4063.

According to the above description, the MCS index value 21 to the MCS index value 31 in the MCS index table can be configured as shown in FIG.

The MS may include checking the modulation information for the downlink data based on the selected MCS index value (S3920). For example, the UE can confirm the information on the modulation method based on the MCS index value included in the received downlink control information. Therefore, in demodulating the downlink data received thereafter, it can be demodulated by referring to the modulation order indicated by the MCS index value included in the downlink control information.

40 is a view for explaining the operation of a base station according to another embodiment of the present invention.

A method for transmitting downlink control information in a base station includes receiving channel state information including information indicating a channel quality state from a terminal, performing an MCS (Modulation and Coding Scheme) index corresponding to a 256QAM modulation method, Selecting one modulation and coding scheme (MCS) index value based on the channel state information in a preset MCS index table including the value of the MCS index, and transmitting the downlink control information including the selected MCS index value .

Referring to FIG. 40, a base station may include receiving channel state information including information on a channel quality state from a terminal (S4000). The channel state information may include information on a result of measuring a channel quality of a downlink channel based on a reference signal, and may include CQI index information.

The base station includes a step of selecting one MCS (Modulation and Coding Scheme) index value based on the channel state information in a predetermined MCS index table including a modulation and coding scheme (MCS) index value corresponding to the 256QAM modulation method (S4010). For example, the base station can select an MCS index value suitable for the channel state using the CQI index information included in the received channel state information and the preset MCS index table.

The present invention relates to the setting of an MCS index value when 256QAM with a modulation order of 8 is introduced. The base station can select one MCS index value from an MCS index table including an MCS index value corresponding to 256QAM.

The MCS index table can be set according to the first to eleventh embodiments as described above. In Fig. 40, the setting of the MCS index table according to the eleventh embodiment will be described.

The MCS index table of the present invention includes five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, It may contain eight MCS index values. That is, a total of 28 MCS index values for HARQ initial transmission can be allocated, and the number of MCS index values according to each modulation order can be allocated as above.

Also, the MCS index table of the present invention may include MCS index values for four HARQ retransmissions and MCS index values for 28 HARQ initial transmissions. For example, as described in the first to eleventh embodiments, in the case of HARQ retransmission, one MCS index value may be assigned to each of the modulation orders 2, 4, 6, and 8, and an MCS index for HARQ initial transmission The index value can be assigned 28.

In addition, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6. For example, as shown in FIG. 4, in the MCS index table in which the maximum value of the modulation order is 6, the maximum transmission efficiency is set to 5.5547. Therefore, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to a transmission efficiency of 5.5547. That is, in the case of the MCS index 21 shown in FIG. 38, the transmission efficiency is set to 5.5547.

One of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to have the same code rate as the code rate with the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6. [ For example, as shown in FIG. 4, in the MCS index table in which the maximum value of the modulation order is 6, the code rate R having the maximum transmission efficiency is set to 948. [ Therefore, one of the MCS index values corresponding to the 256QAM modulation method of the present invention can be set to the code rate 948. [ That is, as shown in FIG. 37, the code rate of the MCS index 27 may be set to 948. FIG.

The MCS index table of the present invention can be set such that each of the MCS index values corresponding to the 256QAM modulation method has the coding rate of FIG. 37, the coding rate of the MCS index value corresponding to the 256QAM modulation method is 711 for the MCS index 21, 754 for the MCS index 22, 797 for the MCS index 23, 841 for the MCS index 24, 885 for the MCS index 25, 885 for the MCS index 25, The index 26 may be set to 916.5 and the MCS index 27 to 948.

In the MCS index table of the present invention, the MCS index value corresponding to the 256QAM modulation method can be set to have the transmission efficiency shown in FIG. As shown in FIG. 38, the MCS index 21 is 5.5547, the MCS index 22 is 5.8906, the MCS index 23 is 6.2266, the MCS index 24 is 6.5703, the MCS index 25 is 6.9141, the MCS index 25 is 6.9141, The index 26 can be set to 7.1602 and the MCS index 27 can be set to have a transmission efficiency of 7.4063.

According to the above description, the MCS index value 21 to the MCS index value 31 in the MCS index table can be configured as shown in FIG.

The MCS index table set in this manner can be stored in the terminal and the base station, respectively. Through this, the UE and the BS can share information on the modulation method through the 5-bit MCS index information.

Hereinafter, a configuration of a terminal and a base station to which all of the above-described present invention can be performed will be described with reference to Figs. 41 and 42. Fig.

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

The terminal 4100 receiving downlink control information includes a transmitter 4120 for transmitting channel state information including information on a channel quality state measured by a base station, and an MCS (modulation and demodulation) a receiving unit 4130 for receiving, from a base station, downlink control information including a MCS (Modulation and Coding Scheme) index value selected based on the channel state information in a preset MCS index table including a coding scheme index value, And a control unit 4110 for checking the modulation information on the downlink data based on the index value.

The transmitter 4120 transmits channel state information including the quality measurement result for the downlink channel. The channel quality measurement result may be included as a CQI index value of the channel state information. In addition, the transmitter 4120 transmits uplink control information, data, and a message to the base station through the corresponding channel.

The receiving unit 4130 receives downlink control information including an MCS (Modulation and Coding Scheme) index value from the base station. The downlink control information received by the receiver 4130 includes modulation information for downlink data. That is, the downlink control information includes information such as a modulation order required for demodulating the downlink data received later by including the MCS index information. The MCS index value included in the downlink control information is a value included in the MCS index table including the 256QAM index value set by the first to eleventh embodiments as described above. The MCS index table may be set according to each of the embodiments described above and stored in the terminal and the base station. In addition, the receiver 4130 receives downlink control information, data, and messages from the base station through the corresponding channel.

The control unit 4110 can check the modulation information for the downlink data based on the selected MCS index value. That is, the modulation information of the downlink data can be checked based on the MCS index value included in the downlink control information, and the downlink data can be demodulated using the identified modulation information. In addition, the controller 4110 controls the overall operation of the terminal according to the present invention described above.

FIG. 42 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

The base station 4200 for transmitting downlink control information includes a receiver 4230 for receiving channel state information including information on a channel quality state from a terminal, a modulation and demodulation unit 4230 for a 256QAM modulation method, a control unit 4210 for selecting one modulation and coding scheme index value based on channel state information in a predetermined MCS index table including a coding scheme index value and a downlink control information (Not shown).

The receiver 4230 can receive channel state information including information on the channel quality state from the terminal. The channel state information includes CQI index information, and the base station can acquire quality information on the downlink channel of the UE according to the CQI index information. Also, the receiver 4230 can receive, from the terminal, signals, messages, and data necessary for carrying out the present invention.

The controller 4210 selects an MCS index value to be transmitted to the UE based on a predetermined MCS index table including CQI index information of the received channel state information and an MCS (Modulation and Coding Scheme) index value corresponding to the 256QAM modulation method. In addition, the controller 4210 can perform modulation of downlink data to be transmitted to the corresponding terminal according to the selected MCS index value. The MCS index table may be set according to each of the embodiments described above and stored in the terminal and the base station. In addition, the controller 4210 controls the overall operation of the base station necessary to perform the above-described present invention.

The transmitting unit 4220 transmits downlink control information including the selected MCS index value to the UE. In addition, the transmitter 4220 can further transmit the downlink data modulated according to the corresponding MCS index information included in the downlink control information. In addition, the transmitter 4220 can transmit signals, messages, and data necessary for performing the present invention to the terminal.

The terminal and the base station may perform all the operations of the present invention described with reference to FIGS. 1 to 40, and may include all the configurations necessary for performing the corresponding operations.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (28)

A method for a terminal to receive downlink control information,
Transmitting channel state information including information indicating a channel quality state to a base station;
(MCS) index value corresponding to a 256QAM modulation method in a predetermined MCS index table including a MCS (Modulation and Coding Scheme) index value, based on the channel state information, Receiving from a base station;
And checking modulation information on downlink data based on the selected MCS index value,
One of the MCS index values corresponding to the 256QAM modulation method,
The maximum modulation order is set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table set to 6, which means the 64QAM modulation method,
The other of the MCS index values corresponding to the 256QAM modulation method,
Wherein the maximum modulation order is set to have the same coding rate as the coding rate with the maximum transmission efficiency of the MCS index table set to 6. The method according to claim 1,
The MCS index table includes:
Five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, and eight MCS index values corresponding to the 256QAM modulation method ≪ / RTI > The method according to claim 1,
The MCS index table includes:
Comprising an MCS index value for four HARQ retransmissions, and comprising an MCS index value for 28 HARQ initial transmissions. The method according to claim 1,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is the MCS index. The method according to claim 1,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same coding rate as the coding rate having the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is the MCS index. The method according to claim 1,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a coding rate of the following table.

The method according to claim 1,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a transmission efficiency shown in the following table.

A method for a base station to transmit downlink control information,
Comprising: receiving channel state information including information on a channel quality state from a terminal;
Selecting one MCS (Modulation and Coding Scheme) index value based on the channel state information in a preset MCS index table including an MCS (Modulation and Coding Scheme) index value corresponding to the 256QAM modulation method; And
And transmitting downlink control information including the selected MCS index value,
One of the MCS index values corresponding to the 256QAM modulation method,
The maximum modulation order is set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table set to 6, which means the 64QAM modulation method,
One of the MCS index values corresponding to the 256QAM modulation method,
Wherein the maximum modulation order is set to have the same coding rate as the coding rate with the maximum transmission efficiency of the MCS index table set to 6. 9. The method of claim 8,
The MCS index table includes:
Five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, and eight MCS index values corresponding to the 256QAM modulation method ≪ / RTI > 9. The method of claim 8,
The MCS index table includes:
Comprising an MCS index value for four HARQ retransmissions, and comprising an MCS index value for 28 HARQ initial transmissions. 9. The method of claim 8,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is the MCS index. 9. The method of claim 8,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same coding rate as the coding rate having the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is the MCS index. 9. The method of claim 8,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a coding rate of the following table.

9. The method of claim 8,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a transmission efficiency shown in the following table.

A terminal for receiving downlink control information,
A transmitter for transmitting channel state information including information indicating a channel quality state to a base station;
(MCS) index value corresponding to a 256QAM modulation method in a predetermined MCS index table including a MCS (Modulation and Coding Scheme) index value, based on the channel state information, A receiving unit for receiving from a base station; And
And a controller for checking modulation information on downlink data based on the selected MCS index value,
One of the MCS index values corresponding to the 256QAM modulation method,
The maximum modulation order is set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table set to 6, which means the 64QAM modulation method,
One of the MCS index values corresponding to the 256QAM modulation method,
Wherein the maximum modulation order is set to have the same coding rate as the coding rate having the maximum transmission efficiency of the MCS index table set to 6 bits. 16. The method of claim 15,
The MCS index table includes:
Five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, and eight MCS index values corresponding to the 256QAM modulation method . 16. The method of claim 15,
The MCS index table includes:
Wherein the HARQ retransmission includes an MCS index value for four HARQ retransmissions and an MCS index value for 28 HARQ initial transmissions. 16. The method of claim 15,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is the MCS index. 16. The method of claim 15,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same coding rate as the coding rate with the maximum transmission efficiency of the MCS index table with the maximum modulation order set to 6 is the MCS index. 16. The method of claim 15,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a coding rate shown in the following table.

16. The method of claim 15,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have the transmission efficiency shown in the following table.

A base station for transmitting downlink control information,
A receiver for receiving channel state information including information on a channel quality state measured from a terminal;
A controller for selecting one MCS (Modulation and Coding Scheme) index value based on the channel state information in a preset MCS index table including an MCS (Modulation and Coding Scheme) index value corresponding to a 256QAM modulation method; And
And a transmitter for transmitting downlink control information including the selected MCS index value,
One of the MCS index values corresponding to the 256QAM modulation method,
The maximum modulation order is set to have the same transmission efficiency as the maximum transmission efficiency of the MCS index table set to 6, which means the 64QAM modulation method,
One of the MCS index values corresponding to the 256QAM modulation method,
Wherein the maximum modulation order is set to have the same coding rate as the coding rate having the maximum transmission efficiency of the MCS index table set to 6 bits. 23. The method of claim 22,
The MCS index table includes:
Five MCS index values corresponding to the QPSK modulation method, six MCS index values corresponding to the 16QAM modulation method, nine MCS index values corresponding to the 64QAM modulation method, and eight MCS index values corresponding to the 256QAM modulation method . 23. The method of claim 22,
The MCS index table includes:
Wherein the base station includes an MCS index value for four HARQ retransmissions and includes an MCS index value for 28 HARQ initial transmissions. 23. The method of claim 22,
Wherein the MCS index value corresponding to the 256QAM modulation method having the same transmission efficiency as the maximum transmission efficiency of the MCS index table in which the maximum modulation order is set to 6 is an MCS index. 23. The method of claim 22,
Wherein the MCS index corresponding to the 256QAM modulation method having the same coding rate as the coding rate having the maximum transmission efficiency of the MCS index table with the maximum modulation order set to 6 is the MCS index 27. [ 23. The method of claim 22,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a coding rate of the following table.

23. The method of claim 22,
The MCS index table includes:
Wherein each of the MCS index values corresponding to the 256QAM modulation method is set to have a transmission efficiency shown in the following table.

Images