WO2017176033A1 - Method and apparatus for decoding random access response message in wireless communication system - Google Patents

Abstract

The present disclosure relates to a communication technique for converging an IoT technology with a 5G communication system for supporting a higher data transmission rate beyond a 4G system, and a system therefor. The present disclosure may be applied to an intelligent service (for example, a smart home, a smart building, a smart city, a smart car or connected car, healthcare, digital education, retail business, a security and security related service, or the like) on the basis of a 5G communication technology and an IoT related technology. A method for a terminal according to the present invention comprises the steps of: transmitting a random access preamble through a resource associated with a resource through which a downlink synchronization signal has been received; receiving a random access response message to the random access preamble; and decoding the random access response message by using information determined on the basis of the resource through which the downlink synchronization signal has been received.

Description

Method and apparatus for decoding random access response message in wireless communication system

The present invention relates to a method for decoding a random access response message in a wireless communication system, and more particularly, to a method for decoding a random access response message using a relationship between a random access preamble message and a random access response message during a random access procedure. will be.

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G communication systems or pre-5G communication systems. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, beamforming, massive array multiple input / output (FD-MIMO), and FD-MIMO are used in 5G communication systems. Array antenna, analog beam-forming, and large scale antenna techniques are discussed. In addition, in order to improve the network of the system, 5G communication systems have advanced small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation The development of such technology is being done. In addition, in 5G systems, Hybrid FSK and QAM Modulation (FQAM) and Slide Window Superposition Coding (SWSC), Advanced Coding Modulation (ACM), and FBMC (Filter Bank Multi Carrier) and NOMA are advanced access technologies. (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, and an Internet of Things (IoT) network that exchanges and processes information between distributed components such as things. The Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers and the like, is emerging. In order to implement the IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between things, a machine to machine , M2M), Machine Type Communication (MTC), etc. are being studied. In an IoT environment, intelligent Internet technology (IT) services can be provided that collect and analyze data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliances, advanced medical services, etc. through convergence and complex of existing information technology (IT) technology and various industries. It can be applied to.

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), machine type communication (MTC), and the like, are implemented by techniques such as beamforming, MIMO, and array antennas. It is. Application of cloud radio access network (cloud RAN) as the big data processing technology described above may be an example of convergence of 5G technology and IoT technology.

Meanwhile, when different terminals transmit the same random access preamble, the base station cannot distinguish different terminals. Accordingly, the base station transmits one random access response, and the terminal receives the same random access response. The random access response may include uplink resource allocation information, and the terminal may transmit a radio resource control (RRC) connection request message through the same uplink resource. Can work. Accordingly, there is a need for a method of setting a relationship between a random access preamble and a random access response message and transmitting different random access responses to different terminals even when the terminal transmits the same random access preamble.

The present invention has been proposed to solve the above-described problem, and the present invention establishes a relationship between a random access preamble and a random access response message in a random access procedure so that even when the UE transmits the same random access preamble, the UEs are different from each other. It is an object of the present invention to provide a method for transmitting another random access response.

Method of the terminal of the present invention for solving the above problems, the step of transmitting a random access preamble through a resource associated with the resource receiving the downlink synchronization signal, receiving a random access response message for the random access preamble And decoding the random access response message using information determined based on the resource receiving the downlink synchronization signal.

In the method of the base station of the present invention for solving the above problems, the method of the base station in a wireless communication system, the method comprising the steps of: receiving a random access preamble through a resource associated with the resource transmitting the downlink synchronization signal, the downlink And transmitting a random access response message based on the resource transmitting the synchronization signal, wherein the random access response message is decoded using information determined based on the resource receiving the downlink synchronization signal.

In addition, the terminal of the present invention for solving the above problems, the transmission and reception unit for transmitting and receiving a signal; And transmitting a random access preamble through a resource associated with the resource receiving the downlink synchronization signal, receiving a random access response message for the random access preamble, and receiving information determined based on the resource receiving the downlink synchronization signal. And a controller configured to decode the random access response message.

In addition, the base station of the present invention for solving the above problems receives a random access preamble through a transceiver for transmitting and receiving a signal, and resources associated with the resource for transmitting the downlink synchronization signal, and transmits the downlink synchronization signal And a controller for transmitting a random access response message based on one resource, wherein the random access response message is decoded using information determined based on a resource receiving the downlink synchronization signal.

According to the present invention, as the relationship between the random access preamble and the random access response message is set, even though different terminals transmit the same random access preamble, each terminal may receive different random access response messages.

1 is a diagram illustrating a random access procedure in LTE.

2 is a diagram illustrating a random access procedure in a beamforming based system according to the present invention.

3A illustrates a method for transmitting a first message according to beam reciprocity in a beamforming based system according to the present invention.

FIG. 3B is a diagram illustrating the first message transmission process shown in FIG. 2 in detail.

4 illustrates various RACH preamble formats according to the present invention.

FIG. 5 illustrates an embodiment in which only one FFT is used when the RACH and the data channel are multiplexed.

FIG. 6 illustrates a case in which FFTs having different sizes are used while using preamble format 2-1.

FIG. 7 is a diagram illustrating an embodiment of setting an RACH transmission time interval during a predetermined period according to the present invention.

8 is a diagram illustrating a random access procedure (RA procedure) according to a first method of establishing a relationship between MSG2 and MSG1.

9 is a diagram illustrating a method in which a RACH resource includes Tx beam information.

10A and 10B illustrate a method of setting a time between MSG2 and MSG1.

11 is a diagram illustrating a relationship between MSG1 and MSG2 according to a preamble ID according to an embodiment of the present invention.

12 illustrates a relationship between MSG1 and MSG2 according to RA-RNTI according to an embodiment of the present invention.

13 is a diagram illustrating an operation sequence of a terminal according to an embodiment of the present invention.

14 is a diagram illustrating an operation sequence of a base station according to an embodiment of the present invention.

15 is a diagram showing the structure of a terminal according to an embodiment of the present invention.

16 is a diagram illustrating a structure of a base station according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents which are well known in the technical field to which the present invention belongs and are not directly related to the present invention will be omitted. This is to more clearly communicate without obscure the subject matter of the present invention by omitting unnecessary description.

For the same reason, in the accompanying drawings, some components are exaggerated, omitted or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same or corresponding components in each drawing are given the same reference numerals.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments of the present invention make the disclosure of the present invention complete and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

At this point, it will be understood that each block of the flowchart illustrations and combinations of flowchart illustrations may be performed by computer program instructions. Since these computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, those instructions executed through the processor of the computer or other programmable data processing equipment may be described in flow chart block (s). It creates a means to perform the functions. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions for performing the processing equipment may also provide steps for performing the functions described in the flowchart block (s).

In addition, each block may represent a portion of a module, segment, or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, the two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the corresponding function.

In this case, the term '~ part' used in the present embodiment refers to software or a hardware component such as an FPGA or an ASIC, and '~ part' performs certain roles. However, '~' is not meant to be limited to software or hardware. '~ Portion' may be configured to be in an addressable storage medium or may be configured to play one or more processors. Thus, as an example, '~' means components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and the like. Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and the 'parts' may be combined into a smaller number of components and the 'parts' or further separated into additional components and the 'parts'. In addition, the components and '~' may be implemented to play one or more CPUs in the device or secure multimedia card.

In addition, in the drawings for explaining the method in the embodiment, the order of the description does not necessarily correspond to the order of execution, and may be changed in parallel or executed in parallel.

In addition, although this invention demonstrates the case of a wireless communication system for the convenience of description for example, the content of this invention is applicable also to a wired communication system.

1 is a diagram illustrating a random access procedure in LTE.

In the initial connection, the base station does not know which terminal is connected. Accordingly, a terminal attempting to access a network through power on or handover may first acquire downlink synchronization through a downlink synchronization signal (SS).

Referring to FIG. 1, the terminal may receive a downlink synchronization signal in step S110. The terminal may perform synchronization using the downlink synchronization signal.

In operation S120, the terminal may transmit a random access preamble to the base station. In the present invention, a message for transmitting the random access preamble may be referred to as a first message or MSG1.

Specifically, the UE acquires random access channel configuration information (RACH) configuration transmitted through a downlink broadcast signal (BCH (Broadcast channel) / SIB (System Information Block), etc.), and based on this, randomly A random access (RA) sequence may be selected and transmitted to the base station (MSG1).

The base station receiving the random access preamble may transmit a random access response (RAR) message (hereinafter referred to as a second message or MSG2) to the terminal in step S130.

Specifically, the base station may detect the RACH from each terminal, and may transmit a random access response message including resource allocation information for uplink transmission to the terminal (MSG2).

The resource on which the random access response is transmitted may be indicated by the DCI transmitted on the PDCCH, and the DCI may be scrambled using the RA-RNTI (addressed to RA-RNTI on PDCCH). In addition, the random access response message may include a physical ID generated based on a preamble identifier, information related to time alignment, initial uplink grant information (uplink resource allocation information), and temporary C-RNTI (temporary C-RNTI). ) May include at least one of information about.

The UE may transmit a random access preamble (or PRACH preamble) and determine that transmission has failed and retransmit if there is no response from the base station for a predetermined time.

In contrast, the terminal receiving the random access response message from the base station may transmit an RRC connection request message (which may be referred to as a third message or MSG 3) to the base station in step S140.

The terminal may transmit a third message by using an uplink resource configured from the base station, and the terminal may transmit a unique ID of the terminal and a message for RRC connection to the third message.

Upon detecting this, the base station may transmit RRC setup information to the terminal in step S150. Through this, the base station may perform contention resolution. At this time, fast contention resolution addressed to temporary C-RNTI for initial access may be possible through temporary C-RNTI for initial access. However, in the non-contention based random access procedure such as handover, only steps S120 and S130 may be performed during the above process.

Meanwhile, a collision occurs during the random access process as follows.

In the process of transmitting the first message MSG1, two different terminals may select the same RA sequence (or RACH sequence) and transmit the same to the base station. The base station detects RACH sequences transmitted from different terminals, but since the RA sequences transmitted by the terminal are the same, the base station cannot distinguish between the different terminals.

Accordingly, the base station transmits only one second message (MSG2) corresponding to the RA sequence, so that two different terminals receive the same MSG2.

Therefore, two different terminals transmit the third message MSG3 using the same uplink resource allocated through the same MSG2. When the base station receives the MSG3 from different terminals, these two MSG3 may act as interference with each other.

Therefore, in the beamforming-based random access process, the base station transmits different MSG2 to different terminals even when the UE transmits the same MSG1 by setting the relationship between MSG1 and MSG2 in order to reduce the probability of dispatching. Suggest a method.

2 is a diagram illustrating a random access procedure in a beamforming based system according to the present invention.

2 shows a random access process under the assumption that there is no beam reciprocity. Beam reciprocity means that a base station or a terminal can use a reception beam as a transmission beam or a transmission beam as a reception beam. That is, the absence of beam reciprocity indicates a state in which a beam used for downlink reception cannot be used as a transmission beam for uplink transmission or a beam used for uplink reception cannot be used as a transmission beam for downlink transmission. .

Referring to FIG. 2, the base station may transmit a downlink synchronization signal every frame in step S210. At this time, the base station can transmit the downlink synchronization signal while changing the transmission beam in the frame. The terminal may detect the downlink synchronization signal while changing the reception beam every frame.

The terminal detecting the downlink synchronization signal selects an RA sequence for random access.

The UE may transmit a random access preamble message (first message) in step S220. In this case, the terminal may repeatedly transmit the first message so that the base station can receive all the reception beams.

3A illustrates a method for transmitting a first message according to beam reciprocity in a beamforming based system according to the present invention.

As described above, in a situation in which there is no beam reciprocity, the beam used for downlink reception cannot be used as a transmission beam for uplink transmission, or the beam used for uplink reception cannot be used as a transmission beam for downlink transmission. The beam reciprocity may be used interchangeably with the term beam correspondence.

The terminal may determine the transmission beam of the base station having the largest signal strength by receiving the downlink synchronization signal of the base station and measuring the same. In this case, if there is a beam association, the UE may assume that the transmission beam will be used as the reception beam, and thus, may select the RACH resource 310 corresponding to the reception beam of the base station (UE Tx config. 1). ). Accordingly, the terminal may transmit a first message on the selected RACH resource 310.

On the other hand, if there is no beam association, the terminal may transmit the first message for the received beams of all base stations (UE Tx config. 2). In this case, the terminal may repeatedly transmit the first message using the fixed beam, and the beam of the terminal may be determined according to whether the terminal has beam relevance.

For example, when the terminal has beam relevance, the terminal may transmit the first message by using the beam receiving the downlink synchronization signal. On the other hand, if the terminal does not have a beam relationship, it can transmit the first message using any beam. However, embodiments of the present invention are not limited thereto, and the terminal may transmit a first message by selecting an arbitrary beam regardless of the beam relevance of the terminal. You can also use the method.

As such, the interval in which the UE transmits the first message may be referred to as a RACH transmission occasion interval, and the RACH transmission timing interval may include one symbol or a plurality of symbols.

That is, in the present invention, one RACH preamble format can be transmitted in the RACH transmission time interval, and the RACH preamble format can transmit one or multiple RACH preambles. One preamble consists of one or multiple RACH sequences, and the RACH sequence consists of one or multiple RACH symbols.

FIG. 3B is a diagram illustrating the first message transmission process shown in FIG. 2 in detail.

As shown in FIG. 3B, a resource capable of transmitting a RACH preamble format is associated with a downlink signal or a channel (DL signal / channel). At this time, as can be seen in Figure 3b, one downlink signal or channel may be associated with one RACH resource, a plurality of downlink signals or channels may be associated with one RACH resource. In addition, although not shown in the figure, one downlink signal or channel may be associated with a plurality of RACH resources.

In this case, the downlink signal or channel may mean a synchronization signal, a reference signal or a broadcast channel. Thus, the downlink signal or channel may be associated with the RACH resource, that is, the downlink signal may be received or the resource where the channel is located may be associated with the RACH resource.

Referring to FIG. 3B, a downlink signal or channel 1 331 may be associated with a subset 341 of RACH resources, and the downlink signal or channel 2 332 may be associated with a subset 342 of RACH resources. Can be. This shows an example in which one occasion for DL signal / broadcast channel is associated with a subset of one RACH resource.

In addition, downlink signals or channels 3 and 4 (333, 334) may be associated with a subset 343 of RACH resources. This shows an example in which a multiple occasion for DL signal / broadcast channel for a downlink signal or channel is associated with a subset of one RACH resource.

Thus, the UE can select a subset of the RACH resources using downlink measurements and corresponding relationships.

In this case, a subset of RACH resources may consist of one or a plurality of RACH resources, and the present invention will be described assuming that a subset of RACH resources consists of one RACH resource. In such a case, the subset of RACH resources may be used in the same concept as the RACH resources. However, embodiments of the present invention are not limited thereto, and the present invention may be equally applied to a case where a subset of RACH resources consists of a plurality of RACH resources.

In this case, when there is no beam reciprocity, when the UE detects a specific DL signal / channel, the UE may select a corresponding RACH resource and transmit a RACH preamble format.

In this case, the UE may transmit one or multiple or repeated preambles during the RACH transmission time interval using the same transmission beam. (During a RACH transmission occasion of single or multiple / repeated preamble (s), UE uses the same UE Tx beam).

On the other hand, when there is beam reciprocity, when the terminal detects the downlink signal or the channel 2 332, the terminal corresponds to the broadcast information (BCH) or the channel 2 332 decoded after detecting the downlink signal, the downlink signal. The RACH preamble format may be transmitted in the RACH resource 342.

Meanwhile, the RACH preamble format consists of one or more RACH preambles, and the RACH preamble consists of one or more RACH sequences and CPs. The RACH sequence consists of one or a plurality of RACH OFDM symbols.

The RACH OFDM symbol may have one or a plurality of subcarrier spacing values. That is, when operating in a low frequency band, it is possible to consider a RACH OFDM symbol (RACH symbol) having a shorter subcarrier spacing compared to a data channel, such as LTE, and when operating in a high frequency band, considering the effect of phase noise Therefore, a RACH OFDM symbol having a subcarrier spacing similar to that of a data channel may be considered. When considering a short length RACH OFDM symbol, repetitive transmission may be performed for coverage expansion.

RACH preamble format for this can be classified as shown in FIG. Here, unlike the format shown in FIG. 4, a general RACH preamble format may be represented as follows.

TABLE 1

Here, Ts represents one sample duration in the time domain. M is the length of the cyclic prefix (CP), G is the length of the guard interval (GT), N is the number of samples of the RACH preamble length (RACH preamble length). In this case, G may mean the number of time domain samples corresponding to GT / Ts.

4 illustrates various RACH preamble formats according to the present invention.

4 shows an example for various RACH preamble format 2. FIG. Referring to FIG. 4, in the first option (Format 2-1), the preamble format may be set such that CP and GT are inserted and RACH preamble is repeatedly transmitted.

In the second option (Format 2-2), the preamble format may be set such that the CP and the RACH sequence are repeatedly transmitted in pairs, and the GT is inserted last.

In addition, in the third option (Format 2-3), the preamble format may be set such that CP, RACH sequence, and GT are repeatedly transmitted in pairs.

In addition, in the fourth option (Format 2-4), the preamble format may be set to be repeatedly transmitted by configuring the RACH preamble with different RACH sequences in the second option (Format 2-2).

In addition, in the fifth option (Format 2-5), the preamble format may be set to be repeatedly transmitted by configuring the RACH preamble with different RACH sequences in the third option.

The RACH preamble format 2 may be set to at least one of the above-described formats 2-1 to 2-5. Alternatively, at least one of the above-described formats 2-1 to 2-5 may be used as separate formats, respectively.

Meanwhile, the preamble format shown in Format 2-1 can be represented as Table 2 below. In Table 2, k is a parameter representing repetitive transmission and may be delivered to the UE through SIB / MIB or higher layer signal.

[Table 2] preamble format 2-1

The option shown in Format 2-1 has an advantage that the data channel decoding and the RACH can be detected using only one FFT when the data channel and the RACH are multiplexed.

FIG. 5 illustrates an embodiment in which only one FFT is used when the RACH and the data channel are multiplexed.

As shown in FIG. 5, an FFT window is adapted to detect a data channel. In this case, since the preamble format is repeated without a CP, orthogonality between preamble OFDM symbols is not broken. Therefore, using an FFT window for decoding the data channel, the RACH symbol can be detected with only phase rotation occurring. However, when only one FFT is used as described above, there is a disadvantage in that a guard interval is included between the beam and the beam.

FIG. 6 illustrates a case in which FFTs having different sizes are used while using preamble format 2-1.

When the FFT for decoding the data channel is performed similarly to the embodiment shown in FIG. 5, data can be decoded without inter-channel interference due to a RACH OFDM symbol having a repetition characteristic of preamble format 2-1. However, when the same FFT is applied to detect the RACH, the orthogonality of the data channel is broken and interchannel interference occurs. Therefore, when detecting the RACH, the band in which the RACH is transmitted should be first filtered in the same manner as in LTE, and the FFT should be performed on the corresponding RACH. In the case of detecting the RACH in this manner, the beam does not need to be matched to the data channel as shown in FIG.

Meanwhile, unlike the preamble format 2-1, 2-2 and 2-3 of the classified preamble formats have a feature of inserting a CP between RACH preambles. Therefore, an orthogonal cover code (OCC) can be applied over several RACH OFDM symbols or RACH sequences as a method for increasing capacity.

For example, assuming that two RACH sequences are repeated, RA capacity can be increased by using OCCs of [1 1] and [1 -1] while using the same RA sequence.

In the case of using the preamble format 2-1, the capacity can be increased through the cyclic prefix in the frequency domain. For example, assuming that the length of the RACH sequence for preamble format 2-1 is N and that the sequence mapped in the frequency domain is x, that is, x [0],. , considering the RACH sequence of x [N-1], the first terminal is x [0], x [1],... , x [N-2], x [N-1] using the RA sequence, the second terminal is x [1], x [2],... The extended RA sequence may be used by utilizing the cyclic prefixes of, x [N-1] and x [0].

Meanwhile, a subset of RACH resources may consist of one or more RACH resources.

In a subset of one RACH resource, the transmit / receive beams of the terminal and the base station may be fixed. In addition, as described above, a subset of one RACH resource may be associated with one or multiple downlink signals or channel timing (DL signal / channel occasion).

In addition, when the base station does not have a beam reciprocity as described above, the terminal transmits the RACH preamble over a subset of all the RACH resources so that the base station can detect the RACH while changing the reception beam, and the base station has a beam reciprocity In addition, one or more RACH preambles may be transmitted by selecting a subset of RACH resources corresponding to DL signal / channel estimated in downlink.

As in the case where there is no beam reciprocity, the UE may transmit a plurality of RACHs during one RACH transmission occasion period. In this case, the base station can receive multiple RACHs while changing the beam of the base station. At this time, the base station cannot assume that the detected RACH preamble ID is transmitted from one terminal even though all of the detected RACHs have the same RACH preamble ID. That is, the base station cannot distinguish whether the detected multiple RACHs are RACHs transmitted from one terminal or RACHs transmitted from a plurality of terminals. Here, the base station may consider the following method for transmitting a random access response.

1-1. Assuming that the base station has received a plurality of received RACH from one terminal, it can transmit one RAR. The RAR may include grant information, and the grant information may include uplink resource allocation information for transmitting MSG3. In addition, the RAR may include timing information for uplink synchronization. When the base station transmits one RAR, it must determine what timing information should be included.

1-1-1. The base station may include timing information in the RAR based on the RACH signal having the largest signal size.

1-1-2. The base station may include timing information in the RAR based on the RACH having the largest propagation delay. When the propagation delay is based on the largest timing, it means that the terminal can transmit the uplink signal at the earliest, and the MSG3 transmission does not collide with the downlink transmission signal of the base station. However, here, the advanced timing information is determined not to exceed the CP range at the base station.

1-1-3. The base station may detect timing information detected from a plurality of RACH signals and classify them into similar timing-groups. When a classified timing group forms a plurality of groups, the base station may adopt a group having the most elements of the timing group and include corresponding timing information in the RAR.

2-1. The terminal receiving one RAR may transmit one MSG3.

On the other hand, unlike the assumption in 1-1, if it is assumed that the plurality of received RACH received from a plurality of terminals from each other, the base station may transmit a plurality of RAR. In this case, the terminal may receive a plurality of RARs.

2-2. Upon receiving the plurality of RARs, the UE may operate as follows depending on which RAR is selected.

2-2-1. The UE may transmit the MSG3 by selecting the RAR having the largest SNR among the plurality of RARs.

2-2-2. The UE may transmit the MSG3 by selecting the RAR having the largest timing advance value among the plurality of RARs. As described above, when the propagation delay is based on the largest timing, it means that the UE can transmit the uplink signal at the earliest, and the MSG3 transmission does not collide with the downlink transmission signal of the base station. . However, here, the advanced timing information is determined not to exceed the CP range at the base station.

2-2-3. The UE may form a timing group according to timing information among a plurality of RARs, and may select a group having the most timing information among the formed timing groups, and select an RAR based thereon to transmit MSG3.

In addition, when there is no beam reciprocity, in order to reduce the total RA time, the base station may set a plurality of RACH transmission occasion intervals for a predetermined period.

FIG. 7 is a diagram illustrating an embodiment of setting an RACH transmission time interval during a predetermined period according to the present invention.

Referring to FIG. 7, the base station of the present invention may set a density of RACH transmissions for a predetermined period. That is, one or more RACH transmission occasions may be allocated for a predetermined period before the UE receives the random access response message.

If the terminal can use the reception beam as a transmission beam, the first message can be transmitted using the beam receiving the downlink synchronization signal, but if the terminal cannot use the reception beam as the transmission beam, the first beam while changing the beam You can send a message. As such, when the UE cannot use the reception beam as a transmission beam, the UE transmits the first message using one beam and attempts to receive the second message, and fails to receive the second message. After transmitting the first message, a process of attempting to receive the second message may be repeated.

When using this method, since it may take a long time, a method of transmitting the first message while changing beams in a plurality of RACH transmission time intervals before the second message is received may be considered.

Accordingly, the UE may transmit the random access preamble through the RACH while changing the transmission beam for each RACH transmission occasion. In this case, the base station may transmit a random access response message (MSG2) to the terminal with respect to the detected random access preamble, and it is necessary to distinguish which MSG1 the MSG2 corresponds to.

In order to establish the relationship between MSG2 and MSG1, the following methods can be considered.

The first method of establishing the relationship between the MSG2 and the MSG1 may be set based on the current LTE scheme and may be used for scheduling of the base station.

8 is a diagram illustrating a random access procedure (RA procedure) according to a first method of establishing a relationship between MSG2 and MSG1.

8 is a diagram illustrating an RA procedure considering two UEs according to an embodiment. Here, it is assumed that the UE selects the same preamble ID of the RACH preamble equally (e.g. Preamble 0). At this time, since the preamble sequence is generated by the preamble identifier, it can be regarded as the same concept. That is, the preamble identifier of the present invention may mean a preamble sequence. Accordingly, the preamble 0 may mean a preamble sequence corresponding to index 0 of the plurality of preamble sequences. For example, when 64 preamble sequences are generated, preamble 0 may mean the first preamble sequence.

UE0 transmits a random access preamble with Preamble ID 0 using the UL Tx beam 0 through PRACH, and UE1 has Preamble ID 0 using the UL Tx beam x. The random access preamble may be transmitted on the PRACH.

The base station (hereinafter, gNB) may detect preambles (or RACHs) transmitted from UE0 and UE1 using different receive (Rx) beams.

The gNB detects a preamble (or RACH) having a preamble ID 0 using different Rx beams, but determines whether the preamble is transmitted from different terminals or whether the preamble transmitted from the same terminal has experienced a multi-channel environment. Can't.

Accordingly, the gNB transmits an RAR including PID (Physical ID) 0 based on the detected Preamble ID 0. That is, the base station may transmit a response message 0 having the PID 0 to the terminal, and the UE0 and the UE1 may detect the response message 0 having the PID 0, respectively. In this case, UE0 and UE1 may receive a response message 0 using the selected reception beam while receiving a DL SS / BCH / beam reference signal (BRS) (the DL RX beam chosen during a group of DL SS). / BCH / BRS). Accordingly, each terminal detecting the RAR having PID 0 assumes that the previous MSG1 transmission is successful and transmits the MSG3 using the same UL Tx beam.

In this case, the two MSG3 signals transmitted by UE0 and UE1 may interact with each other and the gNB may not detect any MSG3. Thus, both UEs may not receive an acknowledgment message (which may be called an Ack message, or MSG4) for MSG3.

Or gNB can detect only one of the two MSG3. In this case, one UE cannot access the gNB, and the process of transmitting MSG1 is performed again.

Referring to FIG. 8, a base station detects an MSG3 transmitted by UE1 by way of example. Accordingly, the base station may transmit the MSG4 including the UE ID 1 to the terminal. Thus, UE1 can connect to the base station.

However, UE0 may not access the base station, and UE0 may transmit a preamble by changing a UL Tx beam at a next RACH time point (UE0 alters UL Tx beam during next PRACH occasion).

Here, although the gNB detects MSG1s of different UEs, it should be noted that collision cannot occur because the MSG1 cannot confirm whether the MSG1s are transmitted from different UEs and cannot transmit MSG2 to different UEs. That is, the beamforming based random access procedure (RA procedure) needs to be defined in consideration of a beam, a RACH transmission resource, a preamble ID, and the like in the LTE based RA procedure.

The second method of establishing the relationship between the MSG2 and the MSG1 is a method of transmitting transmission information including Tx beam information in the MSG2. In this case, the transmission beam information may refer to transmission beam information of a radio transceiver such as a base station, a terminal, a relay, a backhaul, a transmission and reception point (TRP), and the like.

The terminal may determine whether the received MSG2 corresponds to the MSG1 transmitted by the terminal by detecting Tx beam information included in the MSG2. The transmission beam degree may be divided into a transmission beam of a base station and a transmission beam of a terminal as follows.

If the transmission beam information included in the MSG2 is the transmission beam used when the terminal transmits the MSG1, the terminal may confirm that the received MSG2 is for the MSG1 transmitted by the terminal. Accordingly, the terminal may transmit the MSG3 using uplink resource allocation information included in the MSG2. In addition, the terminal may transmit the MSG 3 using the terminal beam included in the MSG2.

When the transmission beam information included in the MSG2 is the transmission beam of the base station, the terminal may transmit the base station beam information estimated when receiving the downlink synchronization signal to the MSG1, and the terminal may transmit the received MSG2 by itself. It can be confirmed that the transmission is for MSG1. Accordingly, the terminal may transmit the MSG3 using uplink resource allocation information included in the MSG2. In addition, the terminal may transmit the MSG3 using the beam of the terminal corresponding to the transmission beam of the base station.

To this end, the base station should be able to estimate the transmission beam (Tx beam) of the base station, the terminal or other equipment while detecting the RACH in the step of transmitting the MSG1. As a method of detecting the ID of the Tx beam by the base station in the step of transmitting the MSG1, the following method may be considered.

1. How a set for an RA sequence includes Tx beam information

2. A method of subset of RACH resource includes Tx beam information

3. How the time domain OCC index includes transmit beam information

4. The combination of preamble indexes includes transmit beam information.

The first method of transmitting the Tx beam information to the base station in the step of transmitting the MSG1 may include a method of increasing the RA sequence set by the number of Tx beam IDs. That is, if 64 preamble IDs are operated in one cell in the existing LTE, the first method may set a preamble ID of 64 x N (number of Tx beams). On the other hand, since the number of Tx beams of the terminal may be different for each terminal or base station, the maximum possible number of Tx beams may be limited and a sequence set may be defined accordingly.

The second method of transmitting Tx beam information to the base station in the step of transmitting the MSG1 is a method in which the RACH resource includes the Tx beam information. As shown in FIG. 3, a time resource of a subset of RACH resources is already associated with a DL signal / channel. Here, the Tx beam information may be included in a frequency index so that a subset of the RACH resources may include the Tx beam information.

9 is a diagram illustrating a method in which a RACH resource includes Tx beam information.

As shown in FIG. 9, frequency indexes of subsets of different RACH resources may include Tx beam information.

A third method of transmitting Tx beam information to a base station in transmitting MSG1 is a method in which a time domain OCC index includes transmission beam information. As described above, an orthogonal cover code may be applied over several RACH OFDM symbols or RACH sequences as a method for increasing capacity. In this case, the index of the orthogonal cover code may include transmission beam information. For example, when considering a preamble for transmitting a plurality of RACH symbols, a time domain OCC may be applied to a plurality of preambles having the same preamble identifier. At this time, if there are M OCC indexes corresponding to the number N of transmission beams, each OCC index may mean a set of N / M transmission beams.

A fourth method of transmitting Tx beam information to a base station in transmitting MSG1 is a method in which a combination of preamble identifiers includes transmission beam information. For example, when considering a preamble for transmitting a plurality of RACH symbols, the plurality of preambles may have different preamble identifiers. When the combination of the preamble identifiers corresponds to the number N of the transmission beams, the base station can determine which transmission beam is used when the combination of the preamble identifiers is detected by the base station.

The third way to establish the relationship between MSG2 and MSG1 is to define the time between MSG1 and MSG2.

10A and 10B illustrate a method of setting a time between MSG2 and MSG1.

Referring to FIG. 10, the terminal may be configured to receive MSG2 after a predetermined time after transmitting MSG1. Accordingly, when the terminal transmits the MSG1 and then receives the MSG2 after the predetermined time, the terminal may recognize that it is a response message to the MSG1 transmitted by the terminal.

In this case, when the MSG2 decoded for a second preset time after the first preset time based on the RACH resource that transmitted the MSG1 exists, the terminal may transmit the MSG3 using uplink allocation information included in the MSG2.

Referring to FIG. 10A, the UE may attempt to decode MSG2 for a second time T3 when a first time T2 has elapsed in each RACH resource. Although FIG. 3 illustrates T3 based on a time point of transmitting MSG1 in the first RACH resource, it is apparent that the T3 section may be changed.

Therefore, when receiving the MSG2 received from the base station and successfully decoding in the T3 period, the terminal may transmit the MSG3 using uplink resource allocation information included in the MSG2.

On the other hand, if MSG2 is not received after the predetermined time (there is no MSG2 being decoded), or if MSG2 is received at a time other than the time when MSG2 is set to be received, it may be recognized that it is not a response message to its MSG1. have.

Therefore, the base station may retransmit the MSG1 after a predetermined time T1 'has elapsed.

On the other hand, the base station may transmit the information on the predetermined time to the terminal. For example, the base station may be configured to receive the MSG2 after a predetermined time or a predetermined subframe after transmitting the MSG1, the information on the predetermined time or a predetermined subframe RACH configuration information transmitted through the SIB or MIB Can be included. Alternatively, the information may be transmitted to the terminal through an upper layer (eg, an RRC layer).

On the other hand, when the MSG2 decoded for a second preset time after the preset first time with respect to the MSG1 transmitted during the RACH transmission time interval based on the RACH transmission time point, the terminal determines the uplink allocation information included in the MSG2 MSG3 can be sent.

Referring to FIG. 10B, the UE may attempt to decode MSG2 for a second time T3 when the first time T2 has elapsed based on the time when MSG1 is transmitted in the first RACH resource. However, in such a case, a situation may occur in which MSG1 transmitted by each RACH resource included in the RACH transmission time interval is not distinguished.

Therefore, when the MSG2 received from the base station is successfully decoded in the T3 period, the MSG3 may be triggered when the UE transmits the MSG3 using uplink resource allocation information included in the MSG2.

On the other hand, if MSG2 is not received after the predetermined time (there is no MSG2 being decoded), or if MSG2 is received at a time other than the time when MSG2 is set to be received, it may be recognized that it is not a response message to its MSG1. have.

Therefore, the base station may retransmit the MSG1 after a predetermined time T1 'has elapsed.

On the other hand, the base station may transmit the information on the predetermined time to the terminal. For example, the base station may be configured to receive the MSG2 after a predetermined time or a predetermined subframe after transmitting the MSG1, the information on the predetermined time or a predetermined subframe RACH configuration information transmitted through the SIB or MIB Can be included. Alternatively, the information may be transmitted to the terminal through an upper layer (eg, an RRC layer).

The time shown in FIG. 10B may be defined as shown in Table 3.

[Table 3] Transmission and processing time of MSG1 and MSG2 during RA procedure

The information included in Table 3 may be transmitted to the terminal through the RACH configuration information transmitted through the SIB or MIB. Alternatively, the information may be transmitted to the terminal through RRC layer signaling.

T means a time point for transmitting the MSG1. T may be configured according to RACH configuration information (RACH configuration).

T1 means the time of one RACH occasion (RACH occasion).

T2 means a delay time until the UE receives the MSG2 and then decodes it.

T3 means a window for receiving MSG2. That is, after transmission of the MSG1, after a certain subframe, it means a time to assume that the MSG2 will be received for a certain number (n) subframes. Here, the predetermined number (n) may inform the UE through RACH configuration information (RACH configuration) transmitted from the SIB / MIB.

However, assuming a situation where a subset of 'M' RACH resources is utilized at one RACH transmission occasion, the m th (0 <m <= M) RACH preamble transmitted on subset of RACH resources and RACH preamble transmitted on subset of RACH resources and the kth (0 <k <= M) RACH resource transmitted on a subset of RACH resources A situation in which the RACH preamble) is not distinguished occurs.

The following describes the situation in which the collision occurs. The access probability when attempting to transmit m MSG1 times can be defined as follows.

, n_s,m, n_d,m, n_d 그리고 n_a 는 [(k-1)T, kT]간의 시간 동안 수집된 값, m 번 시도 시간 동안 전송한 RACH preamble의 횟수, m 번 시도 시간 동안 검출한 RACH preamble의 수, 검출한 RACH preamble의 수, RA에 성공한 단말의 수를 의미한다. here,

, n _{s, m} , n _{d, m} , n _d and n _a are the values collected for the time between [(k-1) T, kT], the number of RACH preambles transmitted in m trials, m trial times The number of detected RACH preambles, the number of detected RACH preambles, and the number of UEs that have succeeded in RA.

The probability of detection failure after m trials is as follows.

In this case, the contention ratio may be expressed as follows.

That is, to reduce the collision probability, a scheme that can lower the contention ratio is required. It is equivalent to increasing the probability that the UE succeeds in the RA by the detected RACH preamble. To this end, the contention ratio can be lowered according to the method of setting the time relationship, which is the third method of establishing the relationship between the MSG1 and the MSG2.

Meanwhile, as shown in FIG. 10A, a method of establishing a relationship between MSG2 and MSG1 may be designed in consideration of one or a plurality of RACH resources within a RACH transmission occasion as shown in Table 4 as follows.

[Table 4] How to set up relationship between MSG1 and MSG2 in beamforming system

The time T1 shown in Table 3 represents one RACH transmission occasion, while T _{1, k} shown in Table 4 represents the time of a subset of RACH resources within one RACH transmission occasion. It may include a time index.

That is, a plurality of RACH resource subsets may be included at one RACH transmission time point, and T _{1, k} may represent indices of the plurality of RACH resource subsets. Accordingly, the terminal transmitting MSG1 in the RACH resource subset indicated by the index may decode MSG2 for a T3 time after the T2 time, and if the MSG2 decoded for the T3 time exists, the MSG2 is included in the MSG2. MSG3 may be transmitted using uplink resource allocation information. On the other hand, if there is no MSG2 to be decoded, the MSG1 may be retransmitted after the T1 'time.

The fourth method for establishing the relationship between MSG1 and MSG2 is to use a preamble ID. In the present invention, the preamble ID may mean a preamble sequence. The method using the Preamble ID may be generated as follows in consideration of a subset of RACH resources.

1. Preamble ID is designed to include a time index of a subset of RACH resources

2. Preamble ID is designed to include frequency index of subset of RACH resource

3. Preamble ID is designed to include frequency and time / index of subset of RACH resource

The RACH preamble ID in LTE is generated as follows. In LTE, 64 preamble IDs are operated, and the UE may select a root index for generating a preamble sequence (RACH OFDM symbol) through a parameter transmitted in SIB2. (Base sequence). The terminal may extend the preamble ID according to the cyclic shift value interval (Ncs) based on the selected root index. In the root index for one RACH OFDM symbol, when the number of preamble IDs extended by the CS value is smaller than 64, the UE selects the next root index to extend the preamble ID. In the extended root index, the preamble ID is extended according to Ncs. In this way, a total of 64 preamble IDs are generated.

The method of generating a preamble ID according to the present invention may be generated by being extended by a time or frequency index of a subset of RACH resources in a method of generating a preamble ID in LTE. have. In the case of preamble format 1 shown in Table 1, a preamble ID may be generated in the same manner as in LTE.

In the case of preamble format 2 (2.1 to 2.5) for a high frequency system, it is difficult to extend the preamble ID in the same way as LTE. This is because, as the symbol length is short, the interval between surf carriers is much larger than that of LTE, so that the length of the sequence in the frequency domain is difficult to allocate as long as LTE. Therefore, when using a root index for generating different preamble sequences (RACH OFDM symbol) in the same resource, the effect of interference is very large, so the root index used in a subset of RACH resources The number of N is very small, which means that it is difficult to extend the preamble ID like LTE.

Accordingly, as in the proposed method, the UE may generate a preamble ID including information indicating a RACH resource, so that the preamble ID may indicate a relationship between the MSG1 and the MSG2. Accordingly, when the MSG2 is detected, the UE may determine which RACH resource succeeds in transmitting the MSG1.

However, as described above, the information indicating the RACH resource may be associated with a downlink signal or a channel. Accordingly, in the present invention, information indicating a downlink signal or a channel may be used to generate a preamble ID. For example, the time or frequency index of the subframe receiving the downlink synchronization signal may be used to generate the preamble ID. However, embodiments of the present invention are not limited thereto, and a subframe or downlink signal that receives a reference signal or a broadcast signal may be used to generate a preamble ID.

11 is a diagram illustrating a relationship between MSG1 and MSG2 according to a preamble ID according to an embodiment of the present invention.

UE0 and UE1 may select the same root index and use the same to generate the same preamble sequence. In addition, UE0 and UE1 may transmit MSG1 in the same subframe. Here, an embodiment in which MSG1 is transmitted using a subset of different RACH resources but using the same subframe is shown.

When the base station receives the RACH, the base station may detect a preamble ID from different RACH resources. Here, the base station establishing the beam reciprocity may determine that different preamble IDs are preamble IDs transmitted from different terminals. On the other hand, the base station without beam reciprocity cannot determine whether the preamble ID detected in different RACH resources is a RACH preamble ID transmitted from the same terminal or a RACH preamble ID transmitted from different terminals.

Accordingly, the base station may assign an identifier (for example, a physical ID (PID)) according to a time or frequency index of a subset of the detected RACH resources. The RAR including the same may be generated and transmitted to the terminal. Here, the time or frequency index of the subset of RACH resources may be represented by the OFDM symbol index / slot index / sub frame index and the start point of the frequency domain of the time when the RACH is transmitted.

As such, by transmitting a response message including different PIDs for each terminal even for the same preamble ID, the terminal may determine whether the response message is transmitted to the terminal.

Referring to FIG. 11, the base station may transmit a RAR including PID 0 to UE0 and may transmit a RAR including PID 1 to UE1.

Accordingly, the terminal may select a MSG2 suitable for the terminal by detecting a PID according to the preamble ID used for the MSG1 transmission among the received RARs. That is, the terminal may detect the PID by decoding the MSG2 and transmit the MGS3 according to uplink resource allocation information included in the MSG2 in which the PID corresponding to the time or frequency index of the RACH resource in which the MSG1 is transmitted is detected.

The fifth method of establishing the relationship between MSG1 and MSG2 is to use RA-RNTI. RA-RNTI is defined as follows in LTE.

The terminal transmitting the MSG1 monitors the PDCCH for the RAR. That is, the UE monitors whether there is an RAR transmitted through the PDCCH. Here, the RAR transmitted through the PDCCH is divided into RA-RNTI. That is, the terminal may distinguish the PDCCH indicating the RAR transmitted to the terminal using the RA-RNTI.

When the UE transmits the MSG1 using the same frequency resource in the same subframe, since the RA-RATI value is the same and the PDCCH according to this value is the same, the UE decodes the PDCCH and decodes the MSG2 indicated by the PDCCH. That is, if the terminal uses the same preamble ID and transmits MSG1 with the same RA-RNTI, even if the base station detects the RACH in a subset of different RACH resources, it may be distinguished that it is transmitted from different terminals. Can't.

Accordingly, the present invention describes a method for the UE to distinguish MSG2 by associating the RA-RNTI with a subset of different RACH resources. The method of associating a RA-RNTI with a subset of RACH resources is as follows.

1. The time index of a subset of RACH resources may be used to generate the RA-RNTI.

RA-RNTI = 1 + t_id, t_id: time index of subset of RACH resource

2. A frequency index of a subset of RACH resources may be used to generate the RA-RNTI.

RA-RNTI = 1 + f_id, f_id: frequency index of subset of RACH resource

3. The time or frequency index of a subset of RACH resources may be used to generate the RA-RNTI.

RA-RNTI = 1 + t_id + f_id

4. A subframe index and a time / frequency index of a subset of RACH resources may be used to generate the RA-RNTI.

RA-RNTI = 1 + t_id + f_id + index of the subframe

However, as described above, the information indicating the RACH resource may be associated with a downlink signal or a channel. Accordingly, in the present invention, information indicating a downlink signal or a channel may be used to generate the RA-RNTI. For example, the time or frequency index of the subframe that received the downlink synchronization signal may be used to generate the RA-RNTI. However, embodiments of the present invention are not limited thereto, and a subframe or downlink signal that receives a reference signal or a broadcast signal may be used to generate the RA-RNTI.

12 illustrates a relationship between MSG1 and MSG2 according to RA-RNTI according to an embodiment of the present invention.

12 illustrates an embodiment of decoding a RAR when a time or frequency index and a subframe index of a subset of RACH resources are associated with a RA-RNTI. Shows.

UE 0 and UE 1 are transmitting the same RACH preamble through a subset of different RACH resources. Accordingly, the base station can detect the same RACH sequence in different RACH resources. Here, the base station without beam reciprocity cannot distinguish whether the RACH sequence transmitted from different terminals or the RACH sequence transmitted from the same terminal. The base station for which the beam reciprocity is established may distinguish the RACH sequence transmitted from different terminals. Since the Preamble ID (RACH sequence) is the same, the PID included in MSG2 is also the same.

However, in the case of using the above-described method, since the MSG1 is transmitted in different RACH resources, the RA-RNTI may be differently determined for each terminal. Accordingly, since the RA-RNTI used to scramble the CRC of the control information indicating the MSG2 is different from each other, the two terminals may decode control information corresponding to the RA-RNTI suitable for the terminal. In addition, MSG2 included in the control information can also be decoded.

The sixth way to establish the relationship between MSG1 and MSG2 is to use the scrambling ID of MSG2. The following describes a method of setting the relationship between MSG1 and MSG2 using the scrambling ID of MSG2. The initial value of scrambling is defined as follows in LTE.

The scrambling ID may be determined according to the scrambling initial value determined as described above. Here, MSG2 is transmitted on PDSCH. Here, n_RNTI is an RNTI associated with the PDSCH, q is a codeword, ns is a slot number, and NcellID is a cell ID.

Accordingly, the present invention proposes a method of differently applying PDSCH scrambling by using a subset of RACH resources when generating an initial value (Cinit). The UE may decode MSG2 suitable for itself by scrambling MSG2 using different scrambling.

Specifically, a method of associating an initial value of scrambling with a subset of RACH resources is as follows.

1. Use the time index of a subset of RACH resources to generate the scramble ID of MSG2

2. Use the frequency index of the subset of RACH resources to generate the scramble ID of MSG2

3. Use the frequency or time index of the subset of RACH resources to generate the scramble ID of MSG2

However, as described above, the information indicating the RACH resource may be associated with a downlink signal or a channel. Accordingly, in the present invention, information indicating a downlink signal or a channel may be used to generate a scrambling ID. For example, the time or frequency index of the subframe receiving the downlink synchronization signal may be used to generate the scrambling ID. However, embodiments of the present invention are not limited thereto, and a subframe or downlink signal that receives a reference signal or a broadcast signal may be used to generate a scrambling ID.

13 is a diagram illustrating an operation sequence of a terminal according to an embodiment of the present invention.

Referring to FIG. 13, the terminal may transmit a random access preamble to the base station in step S1310.

The terminal may receive system information through a broadcast channel before transmitting the random access preamble, and the system information may include random access related configuration information (RACH configuration information). The random access related configuration information may include root index information for generating a random access preamble.

The random access related setting information may further include time information for use in decoding the above-described response message.

When the base station has beam reciprocity, the terminal may transmit a random access preamble in the RACH resource associated with the downlink signal or the channel. On the other hand, when the base station does not have beam reciprocity, the UE may transmit a random access preamble in a RACH transmission occasion section consisting of a plurality of RACH resources.

In operation S1320, the terminal may receive a response message for the random access preamble. The terminal may receive the response message using the selected reception beam while receiving the DL SS / BCH / BRS.

In operation S1330, the terminal may decode the response message using the resource index on which the downlink signal is transmitted. Or, the terminal can decode the response message using the index of the resource including the downlink channel.

The terminal may perform downlink synchronization by receiving a downlink synchronization signal from the base station before transmitting the random access preamble, and the terminal may decode a response message based on the resource receiving the downlink synchronization signal. Alternatively, the terminal may receive system information or broadcast information through a broadcast channel from the base station before transmitting the random access preamble, and the terminal may decode a response message based on a resource for receiving the system information or broadcast information. have.

The decoding step will be described in detail below.

The base station may transmit transmission information including the transmission beam information in the response message, and the terminal may decode the message when the response message includes information corresponding to its transmission beam information or the estimated transmission beam information of the base station. .

In this case, the transmission beam information may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the terminal may include a resource index including a downlink signal or a resource index including a downlink channel. It is possible to determine the transmission beam information using and to decode the response message.

Alternatively, the base station may define a time between the random access preamble and the random access response message, and the terminal may decode the random access response message when the random access response message is received for the time calculated using the time of transmitting the random access preamble.

In this case, the resource transmitting the random access preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the terminal includes a resource index or a downlink channel through which the downlink signal is transmitted. The resource index may be used to determine when a random access preamble is transmitted and when a random access response is to be received, and to monitor whether the response message is received by monitoring the PDCCH during the time. Therefore, when a response message is received during the time, it can recognize that it is a response message to the preamble transmitted by itself and decode it.

Alternatively, when the UE transmits the random access preamble, the UE may determine the RACH resource using the preamble sequence and transmit the same to the base station. The terminal may use the time or frequency index of the resource to transmit the preamble when determining the preamble sequence.

In this case, a resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the terminal may include a resource index including a downlink signal or a resource index including a downlink channel. Determining a time or frequency to transmit a random access preamble using the, to generate a preamble sequence using this can be transmitted to the base station.

Accordingly, the base station can distinguish from which RACH resource the received random access preamble is transmitted, and can transmit a response message to which the physical identifier (PID) is differently assigned according to the time or frequency index of the RACH resource.

Accordingly, the terminal may detect the PID by decoding the response message and determine whether the terminal corresponds to the time or frequency index of the RACH resource that transmitted the random access preamble.

Alternatively, the terminal may scramble control information indicating a resource to which the response message is to be transmitted using the RA-RNTI determined using the time or frequency index of the RACH resource. Specifically, the base station may scramble control information using the RA-RNTI generated by using the time or frequency index of the RACH resource to which the preamble is transmitted, and the terminal descrambles the control information using the RA-RNTI, and controls the The response message received from the resource indicated by the information can be decoded.

As described above, the resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the UE may include a resource index or a downlink channel including a downlink signal. The index may be used to determine the time or frequency to transmit the random access preamble, and the RA-RNTI may be used to descramble the control information. The terminal may decode the response message from the resource indicated by the descrambled control information.

Alternatively, the terminal may decode the response message using the scrambling ID determined using the time or frequency index of the RACH resource. Accordingly, the terminal may decode the response message using the scrambling ID determined using the time or frequency index of the RACH resource.

As described above, the resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the UE may include a resource index or a downlink channel including a downlink signal. The index may be used to determine the time or frequency to transmit the random access preamble, and the scrambling ID may be used to decode the response message.

After decoding the response message by using the above method, the UE may transmit an RRC connection request message to the base station in step S1340. The terminal may transmit the RRC connection request message by using uplink resource allocation information included in the response message.

14 is a diagram illustrating an operation sequence of a base station according to an embodiment of the present invention.

Referring to FIG. 14, the base station may receive a random access preamble in step S1410. In this case, the plurality of terminals may receive the same random access preamble at one RACH transmission time point. Therefore, the base station may transmit the response message by dividing it.

The base station may transmit a response message for the random access preamble in step S1420. At this time, the base station may include specific information so that the terminal can distinguish the response message, or may process the message using the specific information. That is, the base station may generate a response message based on the specific information. In this case, the specific information may be determined based on a resource index on which a downlink signal is transmitted or an index of a resource including a downlink channel.

Accordingly, the terminal may decode the response message using the resource index on which the downlink signal is transmitted. Or, the terminal can decode the response message using the index of the resource including the downlink channel.

Hereinafter, a process of transmitting a response message by the base station will be described in detail.

The base station may transmit transmission information including the transmission beam information in the response message. The base station may estimate the transmission beam and include it in the response message.

In this case, the transmission beam information may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the base station may include a resource index including a downlink signal or a resource index including a downlink channel. The transmission beam information may be determined using the ACK, and may be included in the response message.

Accordingly, the response message may be decoded based on a resource index on which a downlink signal is transmitted or a resource index including a downlink channel.

Alternatively, the base station may define a time between the random access preamble and the random access response message, and may transmit a random access response message after a predetermined time in the RACH resource transmitted with the preamble.

In this case, the resource transmitting the random access preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the terminal includes a resource index or a downlink channel through which the downlink signal is transmitted. The resource index may be used to determine when a random access preamble is transmitted and when a random access response is to be received, and to monitor whether the response message is received by monitoring the PDCCH during the time. Therefore, when a response message is received during the time, it can recognize that it is a response message to the preamble transmitted by itself and decode it. That is, the response message may be decoded based on a resource index on which a downlink signal is transmitted or a resource index including a downlink channel.

Alternatively, when the UE transmits the random access preamble, the UE may determine the RACH resource using the preamble sequence and transmit the same to the base station. Accordingly, the base station may determine whether the preamble is transmitted from which resource using the received preamble sequence, and may transmit a response message to which the physical identifier (PID) is differently allocated according to the time or frequency index of the corresponding resource. .

In this case, the resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and a response message may include a resource index or a downlink channel including a downlink signal. It can be decoded based on the index.

Alternatively, the base station may scramble the control information using the RA-RNTI generated by using the time or frequency index of the RACH resource in which the preamble is transmitted. Accordingly, the terminal may descramble control information using the RA-RNTI and decode a response message received from a resource indicated by the control information.

As described above, the resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the response message includes a resource index or a downlink channel through which the downlink signal is transmitted. Decode based on the resource index.

Alternatively, the base station may scramble the response message using the scrambling ID determined using the time or frequency index of the RACH resource. Accordingly, the terminal may decode the response message using the scrambling ID determined using the time or frequency index of the RACH resource.

As described above, the resource for transmitting the preamble may be associated with a resource index including a downlink signal or a resource index including a downlink channel, and the response message includes a resource index or a downlink channel through which the downlink signal is transmitted. Decode based on the resource index.

In addition, the base station may include uplink resource allocation information in the response message. Therefore, after transmitting the response message, the base station may receive the RRC connection request message in step S1430. The base station may receive the RRC connection request message from the resource according to the uplink resource allocation information included in the response message.

15 is a diagram showing the structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 15, the terminal may include a transceiver 1510, a controller 1520, and a storage 1530.

The transceiver 1510 may transmit / receive a signal with a base station, and may include an interface unit for this. For example, the transceiver 1510 may receive random access related configuration information and a synchronization signal from a base station, transmit a random access preamble, and receive a response message thereto.

The controller 1520 may control the operation of the terminal, and may control the entire terminal to perform the operation described in the above embodiment. In addition, the controller 1520 may include at least one processor. The processor may also be controlled by a program containing instructions for executing the methods described in the embodiments of the present specification. In addition, the program may be stored in a storage medium, and the storage medium may include a volatile or nonvolatile memory. The memory may be a medium capable of storing data, and there is no limitation in the form thereof when the instruction can be stored.

In detail, the controller 1520 may control the random access preamble to be transmitted to the base station. The controller 1520 may receive a response message for the random access preamble. Details of the controller 1520 transmitting and receiving the random access preamble are the same as described above, and will be omitted below.

The controller 1520 may decode the response message using the resource index on which the downlink signal is transmitted. Alternatively, the controller 1520 may decode the response message using the index of the resource including the downlink channel.

The controller 1520 may perform downlink synchronization by receiving a downlink synchronization signal from a base station before transmitting the random access preamble, and the controller 1520 may receive a response message based on the resource receiving the downlink synchronization signal. Can be decoded. Alternatively, the controller 1520 may receive system information or broadcast information through a broadcast channel from the base station before transmitting the random access preamble, and the terminal may receive a response message based on the resource from which the system information or broadcast information is received. Can be decoded.

Details of the decoding step are the same as described above, and will be omitted below.

After decoding the response message by using the above method, the controller 1520 may transmit the RRC connection request message to the base station. The controller 1520 may transmit the RRC connection request message by using uplink resource allocation information included in the response message.

16 is a diagram illustrating a structure of a base station according to an embodiment of the present invention.

Referring to FIG. 16, the base station may include a transceiver 1610, a controller 1620, and a storage 1630.

The transceiver 1610 may transmit and receive a signal with the terminal, and may include an interface unit for this. For example, the transceiver 1510 may transmit random access related configuration information and a synchronization signal to the terminal, receive a random access preamble, and transmit a response message thereto.

The controller 1620 may control the operation of the terminal, and may control the entire terminal to perform the operation described in the above embodiment. In addition, the controller 1620 may include at least one processor. The processor may also be controlled by a program containing instructions for executing the methods described in the embodiments of the present specification. In addition, the program may be stored in a storage medium, and the storage medium may include a volatile or nonvolatile memory. The memory may be a medium capable of storing data, and there is no limitation in the form thereof when the instruction can be stored.

In detail, the controller 1620 may receive a random access preamble. In this case, the plurality of terminals may receive the same random access preamble at one RACH transmission time point. Therefore, the base station may transmit the response message by dividing it.

The controller 1620 may transmit a response message for the random access preamble. In this case, the controller 1620 may include specific information so that the terminal can distinguish the response message, or may process the message using the specific information. That is, the base station may generate a response message based on the specific information. In this case, the specific information may be determined based on a resource index on which a downlink signal is transmitted or an index of a resource including a downlink channel.

Details of the process of the controller 1620 transmitting the response message are the same as described above, and will be omitted below.

In addition, the controller 1620 may include uplink resource allocation information in the response message. Therefore, after transmitting the response message, the controller 1620 may receive the RRC connection request message. The controller 1620 may receive an RRC connection request message from a resource according to uplink resource allocation information included in the response message.

On the other hand, the present specification and the drawings have been described with respect to the preferred embodiments of the present invention, although specific terms are used, it is merely used in a general sense to easily explain the technical details of the present invention and help the understanding of the invention, It is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims (15)

In the method of the terminal in a wireless communication system, Transmitting a random access preamble on a resource associated with a resource receiving the downlink synchronization signal; Receiving a random access response message for the random access preamble; And decoding the random access response message using information determined based on the resource receiving the downlink synchronization signal. The method of claim 1, Transmitting the random access preamble, Receiving random access related setting information through a broadcast channel; The information is, And at least one of a random access radio network temporary identifier (RA-RNTI) or a scrambling identifier determined based on a resource receiving the downlink synchronization signal. The method of claim 1, The decoding step, And decoding the random access response message based on the beam information determined based on the resource receiving the downlink synchronization signal. The method of claim 2, The decoding step, When the random access response message is received for a time determined based on the time index included in the time index of the resource that transmitted the random access preamble and the random access related configuration information, characterized in that for decoding the random access response message Way. A method of a base station in a wireless communication system, Receiving a random access preamble through a resource associated with a resource transmitting the downlink synchronization signal; Transmitting a random access response message based on the resource transmitting the downlink synchronization signal, The random access response message is decoded using the information determined based on the resource receiving the downlink synchronization signal. The method of claim 5, Receiving the random access preamble, Transmitting random access related setting information through a broadcast channel, The random access response message, The random access response message is decoded when transmitted for a time determined based on the time index included in the time index of the resource transmitting the random access preamble and configuration information related to random access, The information is, And at least one of a random access radio network temporary identifier (RA-RNTI) or a scrambling identifier determined based on a resource receiving the downlink synchronization signal. The method of claim 5, The random access response message, And decoding based on beam information determined based on a resource receiving the downlink synchronization signal. A terminal in a wireless communication system, Transmitting and receiving unit for transmitting and receiving a signal; And A random access preamble is transmitted through a resource associated with a resource for receiving a downlink synchronization signal, a random access response message for the random access preamble is received, and information is determined based on the resource for receiving the downlink synchronization signal. And a controller for decoding the random access response message. The method of claim 8, The control unit, Receiving random access related setting information through a broadcast channel; The information is, And at least one of a random access radio network temporary identifier (RA-RNTI) or a scrambling identifier determined based on the resource receiving the downlink synchronization signal. The method of claim 8, The control unit, And decoding the random access response message based on beam information determined based on the resource receiving the downlink synchronization signal. The method of claim 9, The control unit, When the random access response message is received for a time determined based on the time index included in the time index of the resource that transmitted the random access preamble and the random access related configuration information, characterized in that for decoding the random access response message Terminal. A base station in a wireless communication system, Transmitting and receiving unit for transmitting and receiving a signal; And A control unit for receiving a random access preamble through a resource associated with a resource for transmitting a downlink synchronization signal and transmitting a random access response message based on the resource for transmitting the downlink synchronization signal; And the random access response message is decoded using information determined based on the resource receiving the downlink synchronization signal. The method of claim 12, The control unit, Transmitting random access related setting information through a broadcast channel, The information is, And at least one of a random access radio network temporary identifier (RA-RNTI) or a scrambling identifier determined based on the resource receiving the downlink synchronization signal. The method of claim 12, The random access response message, And a base station is decoded based on beam information determined based on a resource for receiving the downlink synchronization signal. The method of claim 13, The random access response message, And the random access response message is decoded when it is transmitted for a time determined based on time information included in a time index of a resource transmitting the random access preamble and configuration information related to random access.

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