KR20150020296A

KR20150020296A - Methods for Transmitting and Receiving System Information and Apparatuses Thereof

Info

Publication number: KR20150020296A
Application number: KR20140010303A
Authority: KR
Inventors: 강승현; 최우진
Original assignee: 주식회사 케이티
Priority date: 2013-08-13
Filing date: 2014-01-28
Publication date: 2015-02-25

Abstract

In case where a portion of information bits among a plurality of MIB information bit blocks is not changed in different MIB transmission periods, the MIB information bit blocks are configured so that a signal obtained by encoding the MIB information bit blocks includes a parity bit that does not vary in the different MIB transmission periods.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for transmitting and receiving system information,

The present invention relates to a method and apparatus for transmitting and receiving system information, and more particularly, to a method and apparatus for transmitting / receiving system information for a terminal located in an enhanced coverage area as compared with coverage for a general terminal.

Machine Type Communication (MTC) or Machine to Machine (M2M) is the communication that takes place between a device and an object with no human intervention or minimal intervention. A "machine" may refer to an entity that does not require direct manipulation or intervention by a person, and "MTC" may refer to a form of data communication involving one or more of such machines. Examples of the "machine" include a smart meter equipped with a mobile communication module, a vending machine, and the like. In recent years, a smart phone The mobile terminal having the MTC function is considered as a type of machine.

The MTC terminal can be installed in a place where the radio wave environment is worse than that of a general terminal. Therefore, the coverage of the MTC terminal should be improved to 20 dB or more in comparison with the coverage of the general terminal.

In order for the MTC terminal to operate at an improved coverage of 20 dB or more as compared to a general terminal, the coverage of the PBCH (Physical Broadcast Channel) that delivers the MIB (master information block) needs to be improved.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for improving the coverage of a PBCH.

A method for receiving system information in an enhanced coverage area in a wireless communication system, the method comprising receiving a MIB (Master Information Block) information bit for a terminal located in the enhanced coverage through a Physical Broadcast Channel (PBCH) Receiving a coded signal using a Tail Biting Convolutional Code (TBCC); Decoding the encoded signal; And acquiring an MIB from the decoded signal, wherein when a part of the information bits among the plurality of MIB information bit blocks in the different MIB transmission periods are not changed, the coded signal is changed in the different MIB transmission periods And a parity bit not included in the system information.

According to another embodiment of the present invention, there is provided a method of transmitting system information to a terminal located in enhanced coverage in a wireless communication system, the method comprising: configuring a MIB (Master Information Block) information bit block for a terminal located in the enhanced coverage; Encoding an MIB information bit block for the UE located in the enhanced coverage using a Tail Biting Convolutional Code (TBCC); And transmitting the coded signal through a PBCH (Physical Broadcast Channel). When a part of the information bits of the plurality of MIB information bit blocks are not changed in different MIB transmission periods, And a parity bit that does not change in another MIB transmission period.

Another embodiment of the present invention is directed to a mobile communication system in which a MIB information bit block for a terminal located in the enhanced coverage through a Physical Broadcast Channel (PBCH) as a terminal located in enhanced coverage in a wireless communication system is transmitted using a Tail Biting Convolutional Code A receiving unit for receiving the encoded signal; And a controller for decoding the coded signal and obtaining an MIB from the decoded signal. When a part of the information bits of the plurality of MIB information bit blocks do not change in different MIB transmission periods, the coded signal is And a parity bit that does not change in the different MIB transmission periods.

Another embodiment of the present invention is a base station for transmitting system information to a terminal located in an enhanced coverage area in a wireless communication system, the MIB information bit block for a terminal located in the enhanced coverage, A controller for encoding the MIB information bit block using a TBCC (Tail Biting Convolutional Code); And a transmitter for transmitting the coded signal through a PBCH (Physical Broadcast Channel). When a part of information bits among a plurality of MIB information bit blocks in different MIB transmission periods are not changed, And a parity bit that does not change in another MIB transmission period.

According to the present invention described above, PBCH with improved coverage can be provided.

1 is a diagram illustrating an initial cell access procedure of a UE.
2 shows the configuration of the MIB.
Figure 3 shows the coding process of the PBCH.
Figure 4 shows the resources through which the PBCH is transmitted.
5 shows a configuration example of a PBCH information bit block.
FIG. 6 shows the initialization of the shift register of the TBCC encoder in the encoding of the PBCH information bit block according to FIG.
FIG. 7 shows the coding of the SFN in the coding of the PBCH information bit block according to FIG.
FIG. 8 shows the encoding of the last 6 bits in the encoding of the PBCH information bit block according to FIG.
FIG. 9 illustrates an exemplary configuration of an MTC information bit block according to an embodiment of the present invention.
FIG. 10 shows an example of an MTC information bit block according to FIG.
FIG. 11 shows TBCC coding of the MTC information bit block according to FIG.
12 shows an example of partial combining of MTC PBCH codewords having different periods.
13 shows an example in which the codeword of the MTC PBCH and the codeword of the general PBCH are partially combined.
FIGS. 14 to 16 show an example of the configuration of an MTC information bit block according to another embodiment of the present invention.
17 is a flowchart illustrating a method of transmitting and receiving MIBs according to an embodiment of the present invention.
18 is a flowchart illustrating a MIB receiving method of a terminal according to an embodiment of the present invention.
FIG. 19 is a flowchart illustrating a method of transmitting an MIB of a base station according to an embodiment of the present invention.
20 is a block diagram showing a configuration of a terminal according to an embodiment of the present invention.
21 is a block diagram showing a configuration of a base station according to an 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 even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a diagram illustrating an initial cell access procedure of a UE.

1, a wireless communication system includes an uplink (e.g., a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical uplink control channel) with a user equipment (PDSCH), a Physical Downlink Control Channel (PDCCH), an Enhanced Physical Downlink Control Channel (EPDCCH), a Physical Random Access Channel (PHICH), and the like. ), A Physical Control Format Information CHannel (PCFICH), a Physical Broadcast CHannel (PBCH), and the like).

In this specification, the terminal 10 is a comprehensive concept of a terminal in a wireless communication. The terminal 10 may be a mobile station (MS), a user terminal (UT) in GSM as well as a UE (User Equipment) in WCDMA, LTE, HSPA, , A subscriber station (SS), a wireless device, and the like.

The base station 20 is generally a station that communicates with the terminal 10 and includes a Node-B, an evolved Node-B (eNodeB), a sector, a Site, a BTS A transceiver system, an access point, a relay node, and the like.

The base station 20 includes various coverage areas such as a megacell, a macro cell, a microcell, a picocell, a femtocell, a radio resource head (RRH), and a relay node communication range.

The base station 20 may be referred to as a Transmission Point (TP) in terms of transmitting downlink communication to the terminal 10 and may be referred to as a Reception Point , RP), or may be referred to as a Point or a Transmission and Reception Point.

Referring to FIG. 1, in the initial cell access procedure of the UE, the UE 10 receives a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS), which are synchronization signals transmitted from the Node B 20 (S 102). In the LTE FDD (Frequency Division Duplex), the PSS can be transmitted in the last symbol (#n) of the first slot of the subframe # 0 and the subframe # 5 in one radio frame (10 ms) May be transmitted in the previous symbol (# n-1) of the last symbol (#n) of the first slot of frame # 5. In LTE TDD, the PSS / SSS can be transmitted at a different location than the FDD. When the terminal 10 detects the PSS and the SSS, it can acquire the cell ID and the downlink synchronization information, and can obtain a cell-specific reference signal (CRS) based on the information obtained based on the PSS / ) To perform additional synchronization and conventional control channel decoding.

The terminal 10 receives the signal from the base station 20 through the PBCH based on the CRS (S104), and extracts the MIB (master information block) transmitted through the PBCH (S106). The MIB may include information indicating the bandwidth of the cell, information indicating the PHICH configuration, and information indicating the system frame number. The terminal 10 can know the resource to which the PDCCH is allocated based on the information included in the MIB.

The terminal 10 receives a signal from the base station 20 via the PDCCH based on the CRS (S108), and extracts downlink control information (DCI) transmitted through the PDCCH (S110). The DCI may be control information for a PDSCH to which a system information block (SIB) is transmitted, and may be transmitted through a common search space.

Based on the DCI, the UE 10 receives the signal through the PDSCH based on the DM-RS from the base station (S112), and extracts the SIB transmitted through the PDSCH (S114).

Thereafter, the terminal 10 and the base station 20 perform a random access procedure (S116), and the terminal 10 can enter the RRC connected state from the RRC idle state.

2 shows the configuration of the MIB. Referring to FIG. 2, the MIB may include a 'dl-Bandwidth' field, a 'phich-Config' field, a 'systemFrameNumber' (or 'SFN') field, and a 'spare' field.

The 'dl-Bandwidth' field can be used to indicate the bandwidth of a cell in resource block (RB) units. In the LTE and LTE-A systems, one cell may be composed of 6, 15, 25, 50, 75, or 100 RBs, and a 3-bit 'dl-Bandwidth' field indicates one of these values. Lt; / RTI >

The 'phich-Config' field can be used to indicate a PHICH resource to which A / N (Acknowledgment / Negative Acknowledgment) to the PUSCH is transmitted. The 'phich-Config' field is composed of 3 bits, and may include one bit for indicating the PHICH duration and two bits for indicating the PHICH resource. The PHICH duration may indicate the number of OFDM symbols to which the PHICH is allocated. If the value of the PHICH duration is 0 (Normal), the PHICH may be located in the first OFDM symbol of the subframe, 1, the PHICH may be located in the first two or three OFDM symbols of the subframe. The PHICH resource can indicate the resource occupancy of the PHICH and can indicate a value of 1/6, 1/2, 1, or 2.

The 'systemFrameNumber' field may be used to indicate a 10-bit system frame number. 8 bits out of 10 system frame numbers are indicated through the 'systemFrameNumber' field, and 2 bits can be acquired implicitly in the decoding of the PBCH which is a period of 4 radio frames (40 ms). Thus, the 'systemFrameNumber' field may include 8 bits from the Most Significant Bit (MSB) of the system frame number.

A 10 bit 'spare' field is reserved.

PDCCH is mapped to a region excluding the PCFICH and the PHICH in the control region, so that the terminal 10 receiving the information of the resource to which the PHICH is allocated through the MIB can know the resource to which the PDCCH is allocated.

MIBs are all composed of 24 bits, and the coding process as shown in FIG. 3 is performed for PBCH transmission. 3 shows a coding process of a PBCH in a base station.

Referring to FIG. 3, a CRC (Cyclic Redundancy Check) of 16 bits is generated using MIB 24 bits (a ₀ , a ₁ , ... a _A _-1 ). At this time, a 16-bit CRC mask set according to the number of transmission antennas is scrambled in the generated 16-bit CRC. A 16-bit scrambled CRC is added after the 24-bit MIB to generate a total of 40 bits of information bit block (i ₀ , i ₁ , ..., i _K _-1 ) (S310). The information bits of 40 bits are encoded using TBCC (Tail Biting Convolutional Code) (S320). TBCC encoded mother code (

,

, ...,

) Is 120 bits in length. The mother code is subjected to a rate matching process and repetition is performed with 1920 bits of codeword e ₀ , e ₁ , ..., e _E-1 at step S330.

Figure 4 shows the resources through which the PBCH is transmitted.

Referring to FIG. 4, the PBCH may be located in the first subframe of each frame on the time axis and in six resource blocks (RB) or 72 subcarriers on the frequency axis. The 1920-bit codeword is transmitted in four frames of 480 bits in the first subframe of each frame. The 480-bit codeword transmitted for each frame is composed of a decodable codeword. For a PBCH code transmitted in four frame periods, the terminal can combine and decode the received values of the codeword transmitted within the corresponding period. If the channel condition between the BS and the channel is good, the UE may succeed in decoding using the received value of the codeword transmitted in one frame. Otherwise, the UE may combine the received values of the codeword transmitted in the maximum of 4 frames So that decoding can be succeeded.

Since the transmission period of the MIB transmitted to the PBCH is 4 frames, if the transmission period is changed, the MIB information can be changed and transmitted. However, the MIB information may have a small change in the bit value or may maintain the same value for a certain period of time. For example, the 'dl-Bandwidth' field indicating the system bandwidth always maintains the same value before the LTE service provider changes its frequency spectrum. Also, the bit value of 10 bits of the 'Spare' field is always set to '0'. The 8 bits s ₀ , s ₁ , ..., s ₇ of the 'systemFrameNumber' field sequentially increase by '1' from the least significant bit (LSB) when the SFN (System Frame Number) value increases. Therefore, in the 4-frame period, s ₀ , s ₁ , ..., s ₇ 8 bits are not changed, and s ₀ , s ₁ , ..., s ₆ 7 bits in the 8-frame period are unchanged and s ₇ 1 Only bits are changed. In the 16-frame period, s ₀ , s ₁ , ..., s ₅ 6 bits are not changed but only s ₆ , s ₇ 2 bits are changed. The 3 bits of the 'PHICH-Config' field are values set by the scheduler of the base station and can be changed every 4 frames at most, but the change period of the value can be variously set in terms of implementation.

5 shows a configuration example of a PBCH information bit block. 5 shows a case where SFN is 0 to 11 as an example. Referring to FIG. 5, it can be seen that the system bandwidth (BW) and the Spare field have a constant value regardless of the SFN. In the example of FIG. 5, the PHICH configuration information is set to be constant. When the SFN is 0 to 11, it can be seen that the last two bits of the MSB 8-bit field of the SFN are sequentially changed while the SFN is increased, and the remaining 6 bits are not changed.

In the example of FIG. 5, it can be seen that the bit values of the CRC are largely changed even though only the last two bits of the SFN are changed in the information bits of the MIB.

Next, a process of TBCC encoding a 40-bit information bit block will be described.

6 shows the initialization of the shift register of the TBCC encoder in the coding of the PBCH information bit block.

6, the 40 bits of the PBCH information bits block BW 3 bits _{(b 0, b 1, b} 3), PHICH 3 bits _{(p 0, p 1, p} 2), SFN of the MSB 8 bits (s ₀ _{, s 1, ..., s 7} ), consists of a sequence of 10 bits spare _{(z 0, z 1, ...} z 9), CRC 16 bits _{(c 0, c 1, ...} , c 15) .

In the first stage of TBCC encoding, the shift register of TBCC is initialized by the bit value of the last 6 bits (c ₁₀ , c ₁₁ , ..., c ₁₅ ) of the PBCH information bit block.

When the k-th information bit i _k of the PBCH information bit block is input, a 3-bit parity bit is formed by a combination of the input information bit and the value stored in the shift register

,

. At this time, when the information bit i _k is input to the first shift register of the encoder, the bit values set in the previous shift register are moved to the right register one by one.

7 shows the coding of the SFN in the coding of the PBCH information bit block. When 'dl-Bandwidth' and 'PHICH-Config' located in the 6 bits of the first bit of the information bit block are coded, the shift register sets the bit values b ₀ , b ₁ and b ₂ of 'dl-Bandwidth' and 'PHICH- , p ₀ , p ₁ , p ₂ . The SFN is encoded according to the set value of the shift register.

8 shows the encoding of the last six bits (c ₁₀ , c ₁₁ , ..., c ₁₅ ) in the encoding of the PBCH information bit block. At this time, the shift registers are set to c ₄ , c ₅ , ... c ₉ . After the last six bits (c ₁₀ , c ₁₁ , ..., c ₁₅ ) are encoded in order, the shift register is again set to c ₁₀ , c ₁₁ , ..., c ₁₅ as shown in FIG. The process of coding such that the values set in the shift register are the same at the start and end of encoding is referred to as tail bit coding.

[ MTC ]

Machine Type Communication (MTC) is defined as communication between a device and an object without human intervention. From the 3GPP perspective, "machine" means an entity that does not require direct manipulation or intervention by a person, and "MTC" is defined as a form of data communication involving one or more of these machines. A typical example of the machine is a smart meter equipped with a mobile communication module, a vending machine, etc. However, recently, a smart phone that performs communication by automatically connecting to a network without any user operation or intervention, The mobile terminal having the MTC function is considered as a type of machine.

[ LTE Low-cost based MTC ]

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

In order to solve this problem, it is necessary to replace a cheap MTC terminal using a GSM / EGPRS network with an MTC terminal using an LTE network, and various requirements for lowering the price of the LTE MTC terminal are required for the 3GPP RAN WG1 standard conference . In addition, the standard meeting is preparing a document (for example, 3GPP TR 36.888) describing various functions that can be provided to satisfy the above requirements.

Major items related to the change of the physical layer standard currently under discussion in 3GPP in order to support the low-cost LTE MTC terminal include technologies such as narrow band support, Single RF chain, Half duplex FDD and Long DRX (Discontinued Reception). However, the above methods, which are considered for lowering the price, can reduce the performance of the MTC terminal as compared with the conventional LTE terminal.

In addition, about 20% of MTC terminals supporting MTC services such as smart metering are installed in a 'Deep indoor' environment such as a basement. Therefore, in order to successfully transmit MTC data, the coverage of LTE MTC terminals is limited to coverage of conventional LTE terminals It should be improved by about 20 dB. In addition, considering the performance reduction due to the above-mentioned specification change, the coverage of the LTE MTC terminal should be improved by 20 dB or more.

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

The requirements of low-cost MTC terminal based on LTE are as follows.

● The data transmission rate should satisfy the minimum data transmission rate provided by MTC terminal based on EGPRS, that is, downlink 118.4kbps and uplink 59.2kbps.

● Frequency efficiency should be improved dramatically compared to GSM / EGPRS MTC terminal.

● The service area provided should not be less than that provided by the GSM / EGPRS MTC terminal.

● Power consumption should not be larger than GSM / EGPRS MTC terminal.

● Legacy LTE terminals and LTE MTC terminals should be available at the same frequency.

Reuse existing LTE / SAE networks.

● Perform optimization not only in FDD mode but also in TDD mode.

• Low-cost LTE MTC terminals should support limited mobility and low power consumption modules.

Among the various physical channels of the LTE system, the PBCH is the first channel for transmitting the system information of the base station. If the UE does not properly receive the PBCH data, it can not receive any downlink data thereafter. In order for the MTC terminal to operate in enhanced coverage, the coverage of the PBCH must also be improved. For example, 3GPP TR 36.888 discloses a method for improving PBCH coverage as follows.

1) a combination of repetition of the current PBCH in the subframe # 0 of the radio frame with every subframe of the radio frame (i.e. new PBCH structure) and PSD boosting (e.g., 4 dB) within 40 ms (for the FDD system) )

- The iterative alone can not satisfy the coverage target for the current PBCH, which changes MIB changes every 40ms according to the SFN update (for example, many repetitions such as 26-95 of the current PBCH in the radio frame).

(1) A combination of repetition of the current PBCH in subframe # 0 of a radio frame onto every subframe of that radio frame (ie a new PBCH structure) and PSD boosting (eg, 4 dB) within 40 ms (for FDD systems )

- The repetition alone can not meet the coverage of the current PBCH where MIB changes every 40ms due to SFN update (eg, as many as 36 ~ 95 repetitions of the current PBCH in a radio frame are needed.

2) New PBCH design (for TDD and FDD systems)

- The new design may consider technologies such as long periods, reduced legacy MIB content, and intermediate transmission. Repeat and / or PSD boosting can be helpful in new designs to meet coverage goals.

- Other system information that needs to be broadcast to the enhanced coverage MTC terminal compared to the MIB content can also be considered for the new PBCH design.

Other low rate coding schemes or spreading may be considered for new designs.

[2] A new PBCH design (for TDD and FDD systems)

- A new design can consider techniques such as: a longer period, reduced legacy MIB content, intermittent transmission. Repetitions and / or PSD boosting may be helpful for new designs.

- Also other system information is required to be broadcasted to enhanced coverage. MTC UEs beside MIB contents can be considered in the new PBCH design.

- Other low rate coding schemes or spreading can be considered for new design.]

3) a complementary PBCH decoding technique (e.g., a correlation decoder or a reduced search space decoder).

The coverage target for the PBCH according to section 9.2 of this TR is 11.7 dB for FDD and 17.7 dB for TDD.

[3] A complementary PBCH decoding technique (e.g., a correlation decoder or a reduced search space decoder).

The coverage target for PBCH according to subclause 9.2 of this TR is 11.7 dB for FDD and 17.7 dB for TDD.

It may be considered to combine at least a part of the MIB transmitted in another PBCH transmission period other than combining the MIBs transmitted repeatedly four times in the PBCH transmission cycle of four frames in order to receive the MIB through the PBCH in order to receive the MIB through the PBCH have.

As described above with reference to FIG. 5, the difference between the bit values of any two MIBs transmitted on the PBCH in each transmission period may be small. However, the values of the two generated CRC bits are different, and the difference between the bit values of the two codewords generated by initializing the shift register of the TBCC encoder with the last six bits of each CRC becomes large.

In other words, some of the PBCH information bits are not changed for a long period of time, but the codewords generated by performing TBCH coding on the bits change greatly in every PBCH transmission period.

In this case, the UE can combine only the received values of the codeword transmitted within one PBCH transmission period, and can not combine the received values of the transmitted codeword in another PBCH transmission period.

Also, in the case of a newly designed PBCH for a coverage enhanced MTC terminal, a part of the MTC PBCH information bits can transmit the same value as the information bits of the general PBCH. In this case, since values of codewords transmitted to the same information transmitted to the MTC PBCH transmitted to the general PBCH and the MTC terminal having improved coverage are different, the received values may not be combined with each other.

Hereinafter, a PBCH coding method for a MTC terminal with improved coverage is disclosed.

First, the base station configures the MTC MIB to be transmitted on the PBCH. Then, the CRC is calculated by the MTC MIB and the CRC is scrambled using the masking code according to the number of the transmission antennas.

The base station may combine the scrambled CRC with the MTC MIB to construct the MTC information bit block so that the content of the MTC MIB with a relatively small change in the value of the information bit over time may be located at the end of the MTC information bit block . At this time, the number of information bits of the contents of the MTC MIB located at the end of the MTC information bit block should be 6 bits or more.

Also, the base station is not located at the last 6 bits of the MTC information bit block, but it can position the content of the MTC MIB at the beginning of the MTC information bit block with a relatively small change in the value of the information bit over time. The modification period of the content of the MTC MIB located at the beginning of the MTC information bit block may be shorter than the modification period of the content of the last MTC MIB.

Then, the base station can place the scrambled CRC and the value of the information bit between the end of the MTC information bit block and the beginning of the MTC information bit block described above, which is changed every PBCH transmission period.

FIG. 9 illustrates an exemplary configuration of an MTC information bit block according to an embodiment of the present invention.

9, the MTC MIB includes 3 bits of 'dl-Bandwidth' indicating the value of the system bandwidth, 3 bits of 'PHICH-Config' indicating PHICH configuration, 8 bits of MSB of the system frame number (SFN) .

The 'dl-Bandwidth' 3 bits and the 'PHICH-Config' 3 bits can be located at the end of the MTC information bit block because the modification period is relatively long.

The 8 bits of the SFN are sequentially changed from the rightmost bit (LSB) as the system frame number increases with time, and the last leftmost bit (MSB) is changed. The 8 bits of the SFN can be located at the beginning of the MTC information bit block since there is little change according to the MIB transmission period.

And, the scrambled CRC may be located in the middle.

FIG. 10 shows an example of an MTC information bit block according to FIG. 10 shows a case where SFN is 0 to 11 as an example. Referring to FIG. 10, when the SFN is 0 to 11, the bit values of the first 6 bits and the last 6 bits of the MTC information bit block are constant and the bit values of the remaining bits are changed according to the MIB transmission period . That is, the first 6 bits of the MTC information bit block are changed to the period of 16 frames (or 4 MIB transmission cycles), and the last 6 bits are almost unchanged.

Meanwhile, in the above-described embodiment, if the MTC MIB includes a spare bit having a bit value of '0', the spare bit may be located at the front or rear of the MTC MIB.

More specifically, when the Spare bit is 6 bits or more, the spare bit is located at the rear of the MTC MIB, and when the TBCC encoding is started, the shift register of the encoder can be set to the LSB 6 bits of the Spare bit. Conversely, if the Spare bit is less than 6 bits, the spare bit can be placed at the front of the MTC MIB.

FIG. 11 illustrates a TBCC encoding process of an MTC information bit block according to FIG. Figure 11 shows the initial TBCC coding.

Referring to FIG. 11, a TBCC shift register is initialized with the bit values of the last 6 bits (b ₀ , b ₁ , b ₂ , p ₀ , p ₁ , p ₂ ) of the MTC information bit block in the first stage of TBCC encoding . When the k-th information bit i _k of the PBCH information bit block is input, a 3-bit parity bit is formed by a combination of the input information bit and the value stored in the shift register

,

10, the first 6 bits of the MTC information bit block are changed to a period of 16 frames, and the last 6 bits are almost unchanged, so that parity bits (k = 0 to 5)

,

, k = 0 to 5) is changed to a period of 16 frames.

Accordingly, the UE can combine the received values of the parity bits k = 0 to 5 out of the PBCH codewords transmitted in up to 16 frames.

In addition, the first 7 bits of the MTC information bit block can be combined with the received values of parity bits of k = 0 to 6 among the PBCH codewords transmitted at a maximum of 8 frames at a period of 8 frames.

Accordingly, the UE can partially combine the received values of the PBCH codeword transmitted in different MIB transmission periods.

12 shows an example of partial combining of received values of MTC PBCH codewords having different periods.

Referring to FIG. 12, the UE may combine received values of a codeword transmitted on a PBCH within a 4-frame period in which a 8-bit SFN bit value is unchanged, and then decode the received values.

In addition, if 3 bits of 'dl-Bandwidth' and 3 bits of 'PHICH-Config' are not changed, the UE transmits parity bits k = 0 to 6

,

, k = 0 to 6) can be partially combined at a maximum of 8 frames, or a parity bit (k = 0 to 5)

,

, k = 0 to 5) can be partially combined at a maximum of 16 frames.

The MTC information bit block consisting of SFN 8 bits, CRC x bits, 'dl-Bandwidth' 3 bits and 'PHICH-Config' 3 bits shown in FIG. 9 and 'dl-Bandwidth' When comparing the PBCH information bit block composed of 3 bits of PHICH-Config, 8 bits of SFN, 10 bits of space, and 16 bits of CRC, the order of dl-Bandwidth 3 bits, PHICH-Config 3 bits, SFN 8 bits Are identical to each other.

Therefore, when the MTC information bit block is transmitted in the same frame as the general PBCH information bit block, the parity bit constituting the codeword of the MTC PBCH and the parity bit constituting the codeword of the general PBCH are expressed by the following Equation 1 Lt; / RTI >

[Equation 1]

,

, where k = 0, 1, ... , 7

In Equation 1, the parity bits (

,

) Is a parity bit constituting a codeword of a general PBCH, and a parity bit (

,

) Is a parity bit constituting the codeword of the MTC PBCH. As can be seen from Equation (1), the same parity bit can be generated for a portion where the information bits of the general PBCH and the information bits of the MTC PBCH are the same.

Therefore, the UE can partially combine the codeword of the MTC PBCH and the received value of the codeword of the general PBCH.

13 shows an example in which the codeword of the MTC PBCH and the codeword of the general PBCH are partially combined.

Referring to FIG. 12, the UE may combine the codeword of the MTC PBCH and the received value of the codeword of the general PBCH in a 4-frame period in which the 8-bit SFN bit value is not changed.

In addition, if the 'dl-Bandwidth' 3 bits and the 'PHICH-Config' 3 bits are not changed, the UE transmits the received value of the parity bit with the bit index k of 0 to 7 among the codewords of the MTC PBCH, It is possible to partially combine the received values of the parity bits whose middle bit index k is 6 to 13.

In addition, if 3 bits of 'dl-Bandwidth' and 3 bits of 'PHICH-Config' are not changed for 8 frames, within 8 frames consisting of two neighboring MIB transmission periods, in which only the last bit value of 8 MSBs of SFN is set differently, The reception values of the MTC PBCH and the general PBCH codeword of different MIB transmission periods can be partially combined. For example, the reception value of the parity bit whose bit index k is 0 to 6 among the codewords of the MTC PBCH transmitted in the frame (SFN mod 8 = 4, 5, 6, 7), (SFN mod 8 = (SFN mod 8 = 0, 1, 2, 3) transmitted from a frame having a bit index k of 0 to 6 among the codewords of the MTC PBCH transmitted in a frame of It is possible to partially combine the received values of the parity bits having the bit index k of 6 to 12 among the codewords of the PBCH.

Meanwhile, contents of the MTC MIB are broadcast to the MTC terminal in addition to 3 bits of 'dl-Bandwidth' indicating the value of the system bandwidth, 3 bits of the PHICH-Config indicating the PHICH configuration, and 8 bits of the MSB of the system frame number (SFN) And y bits of new system information (hereinafter referred to as " NEW ") that are needed.

FIGS. 14 to 16 show an example of the configuration of an MTC information bit block according to another embodiment of the present invention.

It is difficult to combine the reception values of the parity bits generated by the corresponding information bits when the cycle of changing the bit value of the MTC MIB content 'NEW' is short, for example, every four frames of MIB transmission period, such as CRC . In this case, as shown in FIG. 14, the 'NEW' content may be located in the middle portion of the MTC information bit block. In this case, the MTC terminal can partially combine MTC PBCH codewords of different periods or partially combine the codeword of the MTC PBCH and the codeword of the general PBCH in a manner similar to that shown in FIGS. 12 and 13.

If the bit value change period of the MTC MIB content 'NEW' is longer than the SFN change period and shorter than the change period of 'dl-Bandwidth' and 'PHICH-Config', or the change of the bit value of the MTC MIB content 'NEW' When the period is longer than the change period of 'dl-Bandwidth' and 'PHICH-Config' and the size of NEW is less than 6 bits, as shown in FIG. 15, the content 'NEW' is located at the beginning of the MTC information bit block can do. In this case, the parity bits generated by the information bits corresponding to 'NEW' are combined during the frame corresponding to the short change period of the change period of 'dl-Bandwidth' and 'PHICH-Config' can do. However, it may be difficult to partially combine the received values of the codeword of the MTC PBCH and the codeword of the general PBCH.

16, when the change period of the bit value of the MTC MIB content 'NEW' is longer than the change period of 'dl-Bandwidth' and 'PHICH-Config' and the size of NEW is 6 bits or more, 'May be located at the end of the MTC information bit block. At this time, when starting the TBCC encoding, the shift register of the encoder is set to 6 bits of LSB of 'NEW' having a long change period. Also, 'dl-Bandwidth' and 'PHICH-Config' may be located at the beginning of the MTC information bit block. In such a case, information corresponding to 'dl-Bandwidth' and 'PHICH-Config' during a frame corresponding to a short change period of the change period of 'dl-Bandwidth' and 'PHICH-Config' The received value of the parity bit generated by the bit can be combined. In addition, a received value of a parity bit generated by a bit whose value is not changed during the corresponding frame from the first bit of 8 bits of the SFN can be combined. The first 14 bits of the MTC information bit block shown in FIG. 16 and the PBCH information bit block shown in FIG. 5 are equal to 3 bits of 'dl-Bandwidth', 3 bits of 'PHICH-Config' and 8 bits of SFN, It is possible to partially combine the received value of the parity bit having the bit index of 6 to 13 and the received value of the parity bit having the bit index of 6 to 13 among the codewords of the general PBCH.

Meanwhile, in the above embodiment, if the MTC MIB includes a spare bit having a bit value of '0', the spare bit may be positioned at the front or rear of the MTC MIB.

More specifically, when the spare bit is 6 bits or more, the spare bit is located at the rear of the MTC MIB, and when the TBCC encoding is started, the seat register of the encoder can be set to the LSB 6 bits of the spare bit. At this time, a content having a long change period of 'dl-Bandwidth' 3 bits, 'PHICH-Config' 3 bits, or 'NEW' y bits may be located at the front of the MTC MIB.

Conversely, if the spare bits are less than 6 bits, the spare bits can be placed at the front of the MTC MIB. At this time, a content having a long change period of 'dl-Bandwidth' 3 bits, 'PHICH-Config' 3 bits, or 'NEW' y bits may be located at the rear of the MTC MIB.

17 is a flowchart illustrating a method of transmitting and receiving MIBs according to an embodiment of the present invention.

Referring to FIG. 17, a BS configures an MIB information bit block for a terminal (e.g., MTC terminal) located in an improved coverage area (S1710).

In one example, the MIB information bit block for the terminal in the enhanced coverage includes a 'dl-Bandwidth' field for indicating the bandwidth of the cell, a 'PHICH-Config' field for indicating the resources of the PHICH, A " SystemFrameNumber " field, and a CRC. The last part of the MIB information bit block may be composed of a 'dl-Bandwidth' field and a 'PHICH-Config' field, and the first part may be composed of a 'SystemFrameNumber' field.

In another example, the MIB information bit block for the terminal in the enhanced coverage may include a 'dl-Bandwidth' field to indicate the bandwidth of the cell, a 'PHICH-Config' field to indicate the PHICH's resources, A 'NEW' field, which is new system information that needs to be broadcast to the MTC terminal, and a CRC. If the change period of the bit value of the 'NEW' field is shorter than the change period of the bit value of another field, the last part of the MIB information bit block may be composed of a 'dl-Bandwidth' field and a 'PHICH-Config' field, The first part may consist of a 'SystemFrameNumber' field. If the change period of the bit value of the 'NEW' field is shorter than the change period of the bit values of the 'dl-Bandwidth' field and the 'PHICH-Config' and longer than the change period of the bit values of the 'SystemFrameNumber' field, The last part may be composed of a 'dl-Bandwidth' field and a 'PHICH-Config' field, and the first part may be composed of a 'NEW' field. If the change period of the bit value of the 'NEW' field is longer than the change period of the bit values of the 'dl-Bandwidth' field and the 'PHICH-Config', the last part of the MIB information bit block may be composed of a 'NEW' field , The first part may be composed of a 'dl-Bandwidth' field and a 'PHICH-Config' field.

Next, the base station encodes the MIB information bit block for the UE located in the enhanced coverage using the TBCC (S1720), and transmits the encoded signal of the MIB information bit block for the UE located in the enhanced coverage to the UE through the PBCH (S1730). The encoded signal can be repeatedly transmitted in the MIB transmission period of 4 frames.

In step S1740, the UE receives the MIB information bit block for the UE located in the enhanced coverage through the PBCH, and decodes the received signal.

The UE combines the received values of the MIB information bit block encoded for the UE with the MIB information bit block for the UE located in the enhanced coverage within the MIB transmission period of the 4 frames in which the encoded signal is not changed It is possible to decode it.

In addition, the UE can further partially combine the encoded signal of the MIB information bit block for the UE located in the enhanced coverage within another MIB transmission period. Alternatively, the terminal may further partially combine the signal in which the MIB information bit block for the general terminal is coded.

The terminal acquires the MIB from the decoded signal (S1750). The terminal may proceed with the initial cell access procedure of the terminal based on the obtained MIB.

18 is a flowchart illustrating a MIB receiving method of a terminal according to an embodiment of the present invention.

Referring to FIG. 18, in step S1810, the UE receives a signal obtained by coding an MIB information bit block for a UE located in an improved coverage through a PBCH.

The terminal decodes the encoded signal of the MIB information bit block for the terminal located in the received enhanced coverage (S1820).

The terminal acquires the MIB from the decoded signal (S1830). The terminal may proceed with the initial cell access procedure of the terminal based on the obtained MIB.

FIG. 19 is a flowchart illustrating a method of transmitting an MIB of a base station according to an embodiment of the present invention.

Referring to FIG. 19, a BS configures an MIB information bit block for a terminal (for example, an MTC terminal) located in an improved coverage area (S1910).

Next, the base station encodes the MIB information bit block for the UE located in the enhanced coverage using the TBCC (S1920), and transmits the encoded signal of the MIB information bit block for the UE located in the enhanced coverage to the UE through the PBCH (S1930). The encoded signal can be repeatedly transmitted in the MIB transmission period of 4 frames.

20 is a block diagram showing a configuration of a terminal according to an embodiment of the present invention.

Referring to FIG. 20, the terminal 2000 includes a receiving unit 2010, a control unit 2020, and a transmitting unit 2030.

The receiving unit 2010 receives the downlink control information, data, and a message from the base station through the corresponding channel, and the transmitting unit 2030 transmits the uplink control information, data, and message to the base station through the corresponding channel.

The controller 2020 controls the operation of the UE according to the method of configuring the information bits of the PBCH for the UE with improved coverage required for performing the above-described embodiment of the present invention.

More specifically, the receiving unit 2010 receives a signal in which the MIB information bit block for the UE located in the enhanced coverage is encoded through the PBCH.

The control unit 2020 decodes the signal in which the MIB information bit block for the UE located in the received enhanced coverage is coded.

The control unit 2020 receives the MIB information bit block for the UE located in the enhanced coverage within the MIB transmission period of the 4 frames in which the MIB information bit block for the UE located in the enhanced coverage is not changed, Can be combined and decoded.

The control unit 2020 obtains the MIB from the decoded signal. The terminal 2000 may proceed with the initial cell access procedure of the UE based on the obtained MIB.

21 is a block diagram showing a configuration of a base station according to an embodiment of the present invention.

21, the base station 2100 includes a control unit 2110, a transmission unit 2120, and a reception unit 2130.

The controller 2110 controls the operation of the base station according to the method of configuring the information bits of the PBCH for the terminal with improved coverage necessary for performing the above-described embodiment of the present invention.

The transmitter 2120 transmits downlink control information, data, and a message to the terminal through a corresponding channel, and the receiver 2130 receives uplink control information, data, and a message from the terminal through the corresponding channel.

More specifically, the control unit 2110 configures an MIB information bit block for a terminal (e.g., an MTC terminal) located in an enhanced coverage area.

Next, the control unit 2110 codes the MIB information bit block for the UE located in the enhanced coverage using the TBCC. The transmitter 2120 transmits the encoded signal of the MIB information bit block for the UE located in the enhanced coverage to the UE through the PBCH. The encoded signal can be repeatedly transmitted in the MIB transmission period of 4 frames.

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

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

Claims

CLAIMS What is claimed is: 1. A method for a terminal located in enhanced coverage in a wireless communication system to receive system information,
Receiving a signal encoded using a Tail Biting Convolutional Code (MIB) information bit block for a MIB (Master Information Block) for a UE located in the enhanced coverage through a PBCH (Physical Broadcast Channel);
Decoding the encoded signal; And
And obtaining an MIB from the decoded signal,
Wherein the encoded signal includes a parity bit which does not change in the different MIB transmission periods when a part of the information bits of the plurality of MIB information bit blocks do not change in different MIB transmission periods .

The method according to claim 1,
The MIB includes a plurality of information fields,
Wherein the MIB information bit block for the MS located in the enhanced coverage comprises a first portion located at the beginning of the MIB information bit block for the MS located in the enhanced coverage, a last portion located at the end of the MIB information bit block for the MS located in the enhanced coverage, And an intermediate portion located between the first portion and the last portion,
Wherein the last part includes an information field having a longer change period than other information fields of the plurality of information fields,
The first part may include an information field having a shorter modification period than the information field included in the last part and having a longer modification period than the information field included in the intermediate part, or information including a bit value sequentially changed from the least significant bit to the most significant bit Field. &Lt; / RTI >

3. The method of claim 2,
Wherein the size of the last portion is 6 bits or more.

3. The method of claim 2,
Wherein the intermediate portion includes a Cyclic Redundancy Check (CRC) field.

3. The method of claim 2,
Wherein the last part comprises an information field indicating a bandwidth of the system and an information field indicating a PHICH (Physical HARQ Indicator Channel) configuration.

3. The method of claim 2,
Wherein the first portion comprises an information field indicating a system frame number.

The method according to claim 1,
Wherein the decoding comprises:
Combining and decoding a plurality of coded signals of an MIB information block for a terminal located in the enhanced coverage transmitted within one PBCH transmission period; And
If the MIB information block for the UE located in the enhanced coverage transmitted within the one PBCH transmission period has failed to decode after combining a plurality of coded signals, the UE located in the enhanced coverage transmitted within another PBCH transmission period Further comprising decoding at least a part of the encoded signal after combining the MIB information block for the system information.

The method according to claim 1,
Wherein the decoding comprises:
Combining and decoding a plurality of coded signals of an MIB information block for a terminal located in the enhanced coverage transmitted within one PBCH transmission period; And
If the MIB information block for the UE located in the enhanced coverage transmitted within the one PBCH transmission period includes a plurality of coded signals and the decoding fails, the MIB information block for the UE not located in the enhanced coverage is coded And combining and decoding at least a part of the signal.

CLAIMS What is claimed is: 1. A method for transmitting system information in a wireless communication system to a terminal located in enhanced coverage,
Constructing a MIB (Master Information Block) information bit block for the terminal located in the enhanced coverage;
Encoding an MIB information bit block for the UE located in the enhanced coverage using a Tail Biting Convolutional Code (TBCC); And
And transmitting the encoded signal through a PBCH (Physical Broadcast Channel)
Wherein the encoded signal includes a parity bit that does not change in the different MIB transmission periods when a part of the information bits of the plurality of MIB information bit blocks do not change in different MIB transmission periods .

10. The method of claim 9,
The MIB includes a plurality of information fields,
Wherein the MIB information bit block for the MS located in the enhanced coverage comprises a first portion located at the beginning of the MIB information bit block for the MS located in the enhanced coverage, a last portion located at the end of the MIB information bit block for the MS located in the enhanced coverage, And an intermediate portion located between the first portion and the last portion,
Wherein the last part includes an information field having a longer change period than other information fields of the plurality of information fields,
The first part may include an information field having a shorter modification period than the information field included in the last part and having a longer modification period than the information field included in the intermediate part, or information including a bit value sequentially changed from the least significant bit to the most significant bit Wherein the system information includes at least one field.

11. The method of claim 10,
Wherein the size of the last part is 6 bits or more.

11. The method of claim 10,
Wherein the intermediate portion includes a Cyclic Redundancy Check (CRC) field.

11. The method of claim 10,
Wherein the last part comprises an information field indicating a bandwidth of the system and an information field indicating a PHICH (Physical HARQ Indicator Channel) configuration.

11. The method of claim 10,
Wherein the first part comprises an information field indicating a system frame number.

As a terminal located in enhanced coverage in a wireless communication system,
A receiver for receiving a signal encoded using a TBCC (Tail Biting Convolutional Code) for an MIB information bit block for a terminal located in the enhanced coverage through a PBCH (Physical Broadcast Channel); And
And a control unit for decoding the encoded signal and obtaining an MIB from the decoded signal,
Wherein the encoded signal includes a parity bit that does not change in the different MIB transmission periods when a part of the information bits of the plurality of MIB information bit blocks do not change in different MIB transmission periods.

16. The method of claim 15,
The MIB includes a plurality of information fields,
Wherein the MIB information bit block for the MS located in the enhanced coverage comprises a first portion located at the beginning of the MIB information bit block for the MS located in the enhanced coverage, a last portion located at the end of the MIB information bit block for the MS located in the enhanced coverage, And an intermediate portion located between the first portion and the last portion,
Wherein the last part includes an information field having a longer change period than other information fields of the plurality of information fields,
The first part may include an information field having a shorter modification period than the information field included in the last part and having a longer modification period than the information field included in the intermediate part, or information including a bit value sequentially changed from the least significant bit to the most significant bit Field. &Lt; / RTI >

17. The method of claim 16,
Wherein the size of the last portion is 6 bits or more.

17. The method of claim 16,
Wherein the intermediate portion comprises a Cyclic Redundancy Check (CRC) field.

17. The method of claim 16,
Wherein the last part comprises an information field indicating a bandwidth of the system and an information field indicating a PHICH (Physical HARQ Indicator Channel) configuration.

17. The method of claim 16,
Wherein the first portion comprises an information field indicating a system frame number.

16. The method of claim 15,
Wherein,
Combining and decoding a plurality of coded signals of the MIB information block for the UE located in the enhanced coverage transmitted within one PBCH transmission period,
If the MIB information block for the UE located in the enhanced coverage transmitted within the one PBCH transmission period has failed to decode after combining a plurality of coded signals, the UE located in the enhanced coverage transmitted within another PBCH transmission period Wherein the MIB information block for decoding the combined signal further combines at least a part of the encoded signal and then decodes the combined signal.

16. The method of claim 15,
Wherein,
Combining and decoding a plurality of coded signals of the MIB information block for the UE located in the enhanced coverage transmitted within one PBCH transmission period,
If the MIB information block for the UE located in the enhanced coverage transmitted within the one PBCH transmission period includes a plurality of coded signals and the decoding fails, the MIB information block for the UE not located in the enhanced coverage is coded And at least a part of the signal is further combined and decoded.

A base station for transmitting system information to a terminal located in enhanced coverage in a wireless communication system,
A controller configured to construct an MIB information bit block for the UE located in the enhanced coverage and to encode the MIB information bit block for the UE located in the enhanced coverage using a Tail Biting Convolutional Code (TBCC); And
And a transmitter for transmitting the encoded signal through a PBCH (Physical Broadcast Channel)
Wherein the encoded signal includes a parity bit that does not change in the different MIB transmission periods when a part of the information bits of the plurality of MIB information bit blocks do not change in different MIB transmission periods.

24. The method of claim 23,
The MIB includes a plurality of information fields,
Wherein the MIB information bit block for the MS located in the enhanced coverage comprises a first portion located at the beginning of the MIB information bit block for the MS located in the enhanced coverage, a last portion located at the end of the MIB information bit block for the MS located in the enhanced coverage, And an intermediate portion located between the first portion and the last portion,
Wherein the last part includes an information field having a longer change period than other information fields of the plurality of information fields,
The first part may include an information field having a shorter modification period than the information field included in the last part and having a longer modification period than the information field included in the intermediate part, or information including a bit value sequentially changed from the least significant bit to the most significant bit Field. &Lt; / RTI >

25. The method of claim 24,
Wherein the size of the last portion is 6 bits or more.

25. The method of claim 24,
Wherein the intermediate portion comprises a Cyclic Redundancy Check (CRC) field.

25. The method of claim 24,
Wherein the last part comprises an information field indicating a bandwidth of the system and an information field indicating a PHICH (Physical HARQ Indicator Channel) configuration.

25. The method of claim 24,
Wherein the first portion comprises an information field indicating a system frame number.