WO2013168870A1

WO2013168870A1 - Random access method and random access channel structure in mobile communication system having large cell radius

Info

Publication number: WO2013168870A1
Application number: PCT/KR2012/010701
Authority: WO
Inventors: 김희욱; 강군석; 구본준; 안도섭
Original assignee: 한국전자통신연구원
Priority date: 2012-05-08
Filing date: 2012-12-10
Publication date: 2013-11-14

Abstract

The present invention relates to a random access method and a preamble structure therefor for supporting random access from a cell having a radius of 100km or greater and a power-restricted terminal in an LTE-based mobile communication system. The present invention allows: compensating for differences in round-trip delay times between terminals in a wide cell region while reusing an existing LTE random access preamble sequences as is; acquiring a larger link margin, as more power can be transmitted per bandwidth; maintaining compatibility with resource scheduling of an existing LTE; supporting random access from a cell of a large size; and implementing, on the basis of a terrestrial LTE, a preamble structure of a satellite mobile communication.

Description

Random Access Method and Random Access Channel Structure in Mobile Communication System with Large Cell Radius

The present invention relates to a random access method and a preamble structure in an LTE-based mobile communication system for supporting random access in a cell size and a power limited terminal having a radius of 100 km or more.

The present invention was carried out as a result of the research and development of the broadcasting and telecommunications infrastructure source technology of the Korea Communications Commission. [KCA-2012-12-911-01-201, Development of Optimum Application Technology of 2.1GHz Satellite Frequency Band for Terrestrial Mobile Communication]

The present invention relates to a random access and a preamble structure in an LTE-based mobile communication system for supporting random access having maximum compatibility with existing LTE in a cell size and a power limited terminal of 100 km or more in radius.

Future mobile networks are expected to evolve in a way that land and satellite networks combine or cooperate. The commonality between the satellite and the terrestrial air interface in such a satellite / terrestrial integrated system should be considered very important when considering the cost of the terminal. In particular, considering that LTE-based terrestrial mobile systems are being considered as the next generation IMT-Advanced system, LTE (Long) has a much larger cell radius and a long round trip delay time compared to the terrestrial network, and considers a power-limited satellite network environment. The research on Term Evolution based satellite wireless interface is urgently needed.

Meanwhile, two special signals such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) are transmitted in the LTE downlink to help cell search, which is a synchronization acquisition process with cells in a network. Two PSSs in one frame in one cell are identical to each other. In addition, the PSS of one cell may have three different values according to the physical layer cell ID of the cell. More specifically, three cell IDs in one cell ID group correspond to different PSSs.

On the other hand, in any cellular system, a basic requirement is that a terminal should be able to request connection establishment with a network through a process commonly called random access. Random access in LTE is used for several purposes, such as:

-Purpose of establishing a radio link as an initial connection (moving from RRC_IDLE to RRC_CONNECTED);

-Purpose of reforming a radio link after a radio link failure

-The purpose of forming uplink synchronization with a new cell as a hand rover

When the UE is in the RRC_CONNECTED state but the uplink is not synchronized, the purpose of forming uplink synchronization when the uplink or downlink data arrives

-A purpose of making a scheduling request when there is no scheduling request resource specified on a PUCCH (Physical Uplink Control Channel).

Of course, in all the above cases, the primary purpose is to form uplink synchronization during initial access. In addition, the random access process also performs the purpose of assigning the C-RNTI which is a unique identifier to the terminal.

On the other hand, the main purpose of the preamble transmission is to inform the base station that there is a random access attempt and to allow the base station to estimate the delay between the terminal and the base station. The estimation of the delay is used to adjust the uplink timing. The time-frequency resource on which the random access preamble is transmitted is called a physical random access channel (PRACH). The network broadcasts to all terminals which time-frequency resources can be used for random access preamble transmission. As a random access procedure, the UE selects one preamble to be transmitted on the PRACH.

The length of the preamble region in the time domain depends on the preamble setting. The default random access resource is 1ms, but a longer preamble may be configured. In addition, in theory, the uplink scheduler of the eNodeB may leave any long random access area simply by avoiding scheduling of terminals in a plurality of consecutive subframes.

1 is a diagram illustrating a random access procedure of 3GPP LTE adopted as IMT-Advanced radio interface technology. Referring to FIG. 1, the random access procedure of LTE may be represented in four steps. In the first step, synchronization is acquired through a primary synchronization signal (PSS) / second synchronization signal (SSS) from a base station, and system information is obtained through a broadcasting channel (BCH). The information transmitted on the BCH includes parameters for generating a random access preamble. Secondly, the terminal transmits a random access preamble. From this, the eNodeB can estimate the transmission timing of the terminal. The uplink timing estimation is a necessary procedure in the OFDM-based LTE, and uplink data cannot be transmitted unless synchronization is established. In the third step, the base station extracts the transmitted preamble parameter from the base station. In the fourth step, the terminal having the parameter of the preamble detected by the base station informs the acquisition of the uplink sync. Sends Timing_Advanced information necessary for. Finally, the terminal adjusts Timing_Advanced based on the signal transmitted from the base station to make the resource request as the base station.

2 is a diagram illustrating a random access preamble format. Referring to FIG. 2, the random access preamble currently defined in the random access procedure is composed of a cyclic prefix (CP), a preamble sequence, and a guard time (GT), and has four formats. Format 0 consists of 0.1ms of CP and GT, each supporting up to 15km of cells.

Formats

1, 2, and 3 support cell sizes up to 78 km, 30 km, and 100 km, respectively. In

formats

2 and 3, the preamble sequence is transmitted twice, in order to increase energy gain. Preamble transmission uses GT to handle timing uncertainty. Before starting the random access procedure, the UE acquires downlink synchronization from the cell search procedure. However, if uplink synchronization has not yet been established, there is still uncertainty in uplink timing since the location of the terminal in the cell is unknown. As cell size increases, uncertainty in uplink timing increases. The GT is used as part of the preamble transmission to account for timing uncertainties and to avoid interference with subsequent subframes not used for random access. For this purpose, the GT should be defined as a value larger than the sum of the round trip delay difference and the multipath channel delay time between the terminal closest to the eNodeB and the terminal farthest. In the case of Format 4, which has the longest GT, the cell radius is considered to be less than 100 km. Therefore, in the case of a mobile communication network having a cell size of 100 km or more, such as a satellite mobile communication network, the existing preamble format interferes with uplink timing uncertainty and subsequent subframes. The problem cannot be solved.

In addition, the inclusion of the CP in the preamble is efficient because it enables low-frequency frequency domain processing at the base station. For this purpose, the length of the CP should be defined as a value larger than the round trip delay time difference between the terminal closest to the eNodeB and the terminal farthest, and preferably approximately equal to the length of the GT. Finally, by not scheduling any uplink transmission in the subframe following the random access resource, a larger guard interval than shown in FIG. 2 can be generated. Therefore, if the cell size is 100km or more, such as satellite mobile communication network, the round trip delay time difference between terminals exceeds the length of CP, so it is not possible to perform frequency domain processing through one FFT window. Since the receiver complexity and the preamble acquisition time becomes longer.

Finally, in case of satellite mobile communication network, high output signal transmission is needed due to low link margin. When the bandwidth of 1 MHz or more of the uplink random access preamble in LTE is considered a low maximum transmit power level of a handheld type terminal, the power allocated to each subcarrier of the transport block satisfies the link margin of the satellite system. It may not be possible to provide a transmit power that can be. In addition, since the length of the GT and CP to be considered to support a mobile communication network having a wide cell area should be increased compared to the existing LTE, the length of the entire preamble on the time axis should be increased. Considering the existing LTE preamble bandwidth of 1 MHz or more, increasing the preamble length on the time axis causes a reduction in data transmission resources.

The present invention relates to a random access method capable of low frequency domain processing while maintaining compatibility with existing LTE in a mobile communication network having a wide cell area and a power limited environment such as a satellite mobile communication network, and a preamble channel structure thereof.

An object of the present invention is to propose a random access and its preamble structure in an LTE-based mobile communication system for improving system performance while having maximum compatibility with existing LTE in a cell size and a power limited terminal of 100 km or more in radius.

In addition, another object of the present invention is to reduce the uncertainty of the uplink timing generated when the existing terrestrial LTE system is applied to the satellite mobile system.

Another object of the present invention is to provide a preamble structure in which a GT suitable for a satellite mobile system is implemented, so that when the cell size is 100 km or more, the receiver complexity and the preamble are acquired when the difference in the round trip delay time between terminals exceeds the length of the CP. An object of the present invention is to provide a preamble structure including a CP for solving the problem of lengthy time.

In addition, another object of the present invention is to provide a transmission power that can satisfy the satellite mobile system requiring a high power signal transmission due to a small link margin, and the data transmission resources according to the increase in the length of the GT and CP considering the wide cell area To reduce the decrease.

In order to achieve the above object, in the present invention, the terminal determines the size of the cell radius (a); The terminal sets the subcarrier spacing of the random access channel to 1 / n (n is an integer greater than 1) times the subcarrier spacing of the terrestrial LTE data channel and the terrestrial LTE random access channel when the cell radius exceeds a predetermined criterion. b) step; And (c) setting, by the terminal, the length of the random access preamble to m (m is an integer greater than 1) times the length of the terrestrial LTE subframe. A random access channel generation method is provided.

Preferably, the random access preamble includes a random access preamble sequence, a cyclic prefix (CP), and a guard time (GT).

In addition, the determination unit for determining the size of the cell radius; When the cell radius determined by the determination unit exceeds a predetermined criterion, the subcarrier spacing of the random access channel is set to 1 / n (n is an integer greater than 1) times the subcarrier spacing of the terrestrial LTE data channel and the terrestrial LTE random access channel. And a second setting unit for setting the length of the first setting unit and the random access preamble to m (m is an integer greater than 1) times the terrestrial LTE subframe length. An apparatus for creating a random access channel is provided.

Specific details of other embodiments are included in the detailed description and the drawings.

According to the present invention, the existing LTE random access preamble sequence can be recycled as it is, and it is possible to compensate for the round trip delay time difference between terminals in a wide cell area. In addition, the bandwidth of the random access channel of the present invention is 1/3 of the existing random access channel bandwidth, and the power-limited terminal can transmit higher power per bandwidth, thereby securing more link margins. In addition, according to the present invention, the remaining channel bandwidth 1/3 can be used as the minimum resource allocation block of the existing LTE to maintain compatibility with the resource scheduling of the existing LTE, it is possible to support random access in a large cell size, There is an effect that can implement the preamble structure of satellite mobile communication based on terrestrial LTE. These effects, in turn, enable the support of large cell structures even under low power terminals and ensure compatibility between terrestrial LTE and LTE-based satellite mobile communications.

1 is a diagram illustrating a random access procedure of 3GPP LTE adopted as an IMT-Advanced radio interface technology.

2 illustrates a random access preamble format.

3 is a diagram illustrating a propagation delay time difference according to positions of a satellite and a terminal within one spot beam coverage.

4 illustrates a random access channel structure.

5 is a diagram illustrating mapping of a proposed random access preamble to an existing data transport block.

6 illustrates a procedure of transmitting and receiving a random access channel with the proposed random

access channel formats

4 and 5;

FIG. 7 shows a procedure connected to B of FIG. 6.

8 shows a procedure connected to C of FIG.

In order to achieve the above object, the present invention is to compensate for the difference in the round trip delay time between the terminals in a wide cell area while recycling the existing random access preamble sequence of LTE in a mobile communication system having a wide cell area, In this paper, we propose a narrowband random access channel structure to secure link margins and propose a random access method using the same.

According to one preferred embodiment of the invention, the step of determining the size of the cell radius (a); (B) setting the subcarrier spacing of the random access channel to 1 / n (n is an integer greater than 1) times the subcarrier spacing of the terrestrial LTE data channel and terrestrial LTE random access channel when the cell radius exceeds a predetermined criterion. ; And setting the length of the random access preamble to m (m is an integer greater than 1) times the length of the terrestrial LTE subframe.

According to a preferred embodiment of the present invention, a comparison unit for determining the size of the cell radius; A first setting unit configured to set a subcarrier spacing of a random access channel to 1 / n (n is an integer greater than 1) times the subcarrier spacing of a terrestrial LTE data channel and a terrestrial LTE random access channel when the cell radius exceeds a predetermined criterion And a second setting unit that sets the length of the random access preamble to m (m is an integer greater than 1) times the length of the terrestrial LTE subframe.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the embodiment, the present invention will be described with the LTE-based satellite mobile communication system, but the method of the present invention can be applied regardless of any other mobile communication system having a wide cell area.

3 is a diagram illustrating a propagation delay time difference according to positions of a satellite and a terminal within one spot beam coverage. Referring to FIG. 3, a preferred embodiment of the present invention will be described.

Here, the parameters of FIG. 3 mean the following.

h: Satellite height

r _E : Earth radius

d: Satellite-terminal distance

α: angle at which the terminal is located on the satellite

β: angle at which the terminal is located from the center of the earth

θ: elevation angle at the terminal or earth station

In FIG. 3, it is assumed that LES (Land Earth Station) and UE (User Equipment) 1 are located at the edge of satellite coverage and UE2 is the innermost of the largest spot beam coverage in FIG. 3 using the parameters defined above. The propagation delay time, t ₁ and t _2, and the delay time difference Δt ₁ , ₂ between each satellite and the terminal can be obtained by the following relationship.

First, when θ ₁ , β ₁ , α _1,2 and β _1,2 are defined as

θ ₁ : minimum elevation angle

β ₁ : satellite coverage angle

α _1,2 = α ₁ -α ₂ : Spot beam angle with maximum magnitude

β _1,2 = β ₁ -β ₂ : Spot beam coverage angle with maximum magnitude

The relationship between coverage angle and elevation angle

The spot beam coverage diameter s _1,2 along the ground surface for the maximum spot beam has the following relationship with the maximum spot beam coverage angle β _1,2 .

In addition, the distance between each terminal and the satellite has the following relationship.

Given the altitude h, the minimum elevation angle θ ₁ , the beam coverage diameter s _1,2 , and the earth radius r _E , when the distance d between the satellite and the terminal is obtained from the above relation, the propagation delay time t _i is

Same as Where c is the speed of propagation. Also the propagation time difference

Can be obtained as

The difference in propagation time depends on the satellite altitude and spot beam coverage. Considering the GEO satellite, which is currently being considered for personal mobile satellite mobile communication worldwide, and the elevation angle of 40 ° where Korea is located, it is the largest in LTE. In the case of the random access channel format 4 capable of supporting a cell, it is possible to support a cell radius of 100 km in a terrestrial mobile communication system, but in the case of a satellite mobile communication system, only a cell radius of 75 km is supported. In the case of satellite communication system, the total system capacity can be maximized by minimizing the multiple beams, and the size of the satellite beam is considered that the data transmission capacity can be increased as the length of CP and GT in the random access channel is smaller. It is efficient to make it small. Therefore, in the LTE-based satellite mobile communication network, the random access channel should be able to support 150km ~ 200km of cell radius that can be made by current satellite antenna technology. When considering the GEO satellite and the Korean elevation angle of 40 ° as described above, this should support the round trip delay time, 1.8ms between the terminal closest to the satellite base station and the farthest terminal in the random access channel. That is, the length of the random access preamble and the length of the CP should be 1.8 ms or more.

In addition, in order to increase the length of the time axis of the preamble, reduce the bandwidth of the random access channel to consider the power-limited satellite environment, and reuse the existing LTE preamble sequence as it is, the subcarrier spacing of the proposed random access channel is It should be less than the subcarrier spacing. In order to minimize loss of orthogonality between the preamble subcarrier and the data subcarrier and to facilitate implementation by reusing existing FFT / IFFT blocks for PUSCH data, the subcarrier spacing for PUSCH data must be an integer multiple of the random access channel subcarrier spacing. That is, the subcarrier spacing of the proposed random access channel is designed to be 1 / n (n is an integer greater than 1) times the data channel subcarrier spacing of the existing LTE and the random access channel subcarrier spacing of the existing LTE.

Therefore, considering that the length of the sequence of the random access preamble format 1 of the existing LTE is 800us, the minimum length of the integer multiple of 800us is larger than 1.83ms in the wide cell, and thus has a wide cell area. If the sequence length of the random access preamble is defined to be 2.1 ms, this is 36 times the random access channel subcarrier interval proposed by the subcarrier spacing for the existing data and 3 times the random access subcarrier interval proposed by the existing LTE random access channel spacing. Because of this, the orthogonality with the existing channel can be maintained and the FFT and IFFT blocks of the existing LTE can be reused for easy implementation. Also, in this design, the bandwidth of the proposed random access channel is 1/3 of the existing random access channel bandwidth, so that more link margins can be secured because higher power per bandwidth can be transmitted from a power-limited terminal. In addition, the remaining channel bandwidth 1/3 corresponds to the number of two resource blocks for the existing data channel, which corresponds to the minimum resource allocation block size of the existing LTE. Therefore, there is an advantage that can implement the proposed random access channel while maintaining compatibility with the resource scheduling of the existing LTE.

Next, the GT's length should be at least 1.8ms to ensure uncertainty in the round trip delay time. The length of CP should be more than the sum of the round trip delay difference and the multipath channel delay time. Since the satellite is usually communicated in a line of sight environment, the multipath channel delay time can be considered to be 0. You can define similar lengths. Since the proposed random access channel must operate within the existing LTE frame structure in order to maintain compatibility with the existing LTE, the length of the random access channel (preamble) is an integer (m, m greater than 1) of the LTE subframe length (1 ms). Integer) times. Since the sequence length of the random access channel is 2.4ms, when the length of the CP and GT is approximately 1.8ms, the length of the random access channel is 6ms, corresponding to six subframes. In order to facilitate the implementation, the length of CP is defined as 9 times the CP length of the existing LTE random access channel format 2 corresponding to approximately 1.8 ms, so that the length of the CP is an integer multiple of the existing LTE random access channel format. GT is defined except the sequence length of 2.4ms and CP length.

On the other hand, since the link margin for random access may not be secured when the cell size is large or the terminal does not transmit with sufficient power, another random access channel format that doubles the sequence length is defined to consider this case. do. Therefore, the random access channel sequence length of this format is 4.8 ms. Since the sequence length of the random access channel is 4.8 ms, when the length of the CP and GT is approximately 2.1 ms, the length of the random access channel is 9 ms, corresponding to nine subframes. In order to facilitate the implementation, the length of the CP is defined as 9 times the CP length of the existing LTE random access channel format 2 corresponding to approximately 1.8 ms in order to be an integer multiple of the existing LTE random access channel format. GT is defined except the sequence length of 4.8ms and CP length.

4 illustrates a random access channel structure.

Table 1 defines the random access channel parameters of FIG. 4, where Ts has a value of Ts = 1 / (15000 × 2048) as the sampling period.

The frequency multiplexing method with the existing LTE transport block to operate the proposed random access channel preamble without interference while maintaining compatibility with the existing LTE data transport block is as follows.

here

Is the number of uplink transmission resource blocks,

Means the resource block that is first allocated for PRACH, and this value is defined in higher layer.

Is defined by

In case of the basic LTE, a random access preamble is generated from the Zadoff-Chu sequence having a length of 839. The proposed random access channel also reuses the existing Zadoff-chu sequence of the existing LTE in order to reduce the terminal chipset cost while maintaining compatibility with the basic LTE. . In order to transmit the Zadoff-Chu sequence-based random access preamble in a 1/3 bandwidth than the conventional random access channel signal is transmitted as follows.

Where t is

Has a value of,

Is the scaling index for determining the transmit power,

Random access preamble sequence,

to be. The position in the frequency domain is a parameter that is the first physical resource block allocated for the PRACH advertised by the upper layer

Controlled by Also

The value indicates a difference between the subcarrier spacings for the random access and uplink data transmission. Variable indicating the proposed random access preamble subcarrier spacing

The offset phi value for determining the frequency domain position of the random access preamble in the PHY and physical resource blocks is defined as shown in Table 2 below without losing orthogonality while maintaining compatibility with the existing data transmission block.

FIG. 5 is a diagram illustrating mapping of a proposed random access preamble to an existing data transport block as described above. 6 to 8 are diagrams illustrating a procedure for transmitting and receiving a random access channel with the proposed random

access channel formats

4 and 5. FIG. Referring to FIGS. 5 to 8, when a cell radius capable of operating in the existing random access channel format is R _TH1 , when the cell radius is less than R _TH1 , it is possible to operate even with the existing random access channel format. With

format

0, 1, 2, 3, the random access channel can be transmitted and received by the existing LTE method. In the case of the satellite mobile network considered above, R _TH1 would be 75 km. On the other hand, when the cell radius is _greater than R _TH1 , the conventional formats use the random access channel formats 5 and 6 because they result in the reception of random access preambles and system capacity degradation through low-frequency frequency domain processing. When the cell radius corresponding to a maximum radius of the round trip delay time between terminals is R _TH2 , random access uses format 4 if sufficient link margin between the satellite and the terminal is secured. The random access channel of Format 4 has a bandwidth corresponding to 2RB in the frequency domain and a time interval corresponding to six subframes in the time domain. Accordingly, the base station allocates a transmission resource interval corresponding to format 4 for the random access channel. The base station may schedule data transmission outside the resource interval allocated for the random access channel. The transmission resource for the random access channel allocated by the base station is received by the terminal through the BCH, and the terminal transmits an uplink random access signal in the allocated transmission period based on this information. Since the signals transmitted from each terminal arrive within the CP section of the format 4 at the base station, the preamble detection scheme is reused in the existing LTE as it is and preamble detection through low complexity frequency domain processing is performed in one FFT. On the other hand, if sufficient link margin between the satellite and the terminal is not secured, random access uses format 5. The random access channel of Format 5 has a bandwidth corresponding to 2RB in the frequency domain and a time interval corresponding to 9 subframes in the time domain. Accordingly, the base station allocates a transmission resource interval corresponding to format 5 for the random access channel. The base station may schedule data transmission outside the resource interval allocated for the random access channel. The transmission resource for the random access channel allocated by the base station is received by the terminal through the BCH, and the terminal transmits an uplink random access signal in the allocated transmission period based on this information. Since the signals transmitted from each terminal arrive within the CP section of the format 5 at the base station, the preamble detection method is reused as it is in the existing LTE, and preamble detection is performed through low complexity frequency domain processing in one FFT. The proposed format 5 is used in the same way even if the cell radius R _TH3 or less within a maximum 2.1ms round-trip delay time between terminals.

However, when the round trip delay time difference between the terminals exceeds the cell radius R _TH3 , since the random access signals transmitted by the terminals may be received outside the CP interval, frequency domain processing cannot be performed in one window. Therefore, in this case, preamble detection is performed through high-complexity time-domain processing in multiple windows.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the devices and components described in the embodiments are, for example, processors, controllers, Arithmetic Logic Units (ALUs), Digital Signal Processors (Microcomputers), Microcomputers, Field Programmable Gate Arrays (FPGAs). May be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process and generate data in response to the execution of the software. For convenience of explanation, one processing device may be described as being used, but one of ordinary skill in the art will appreciate that the processing device includes a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as parallel processors.

The software may include a computer program, code, instructions, or a combination of one or more of the above, and configure the processing device to operate as desired, or process it independently or collectively. You can command the device. Software and / or data may be any type of machine, component, physical device, virtual equipment, computer storage medium or device for the purpose of interpreting or providing instructions or data to the processing device. Or may be permanently or temporarily embodied in a signal wave to be transmitted. The software may be distributed over networked computer systems so that they may be stored or executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims

(A) determining, by the terminal, the size of the cell radius;

The terminal sets the subcarrier spacing of the random access channel to 1 / n (n is an integer greater than 1) times the subcarrier spacing of the terrestrial LTE data channel and the terrestrial LTE random access channel when the cell radius exceeds a predetermined criterion. b) step; And

And (c) setting, by the terminal, the length of the random access preamble to m (m is an integer greater than 1) times the length of the terrestrial LTE subframe. How to create an access channel.
The method of claim 1,

The random access preamble includes a random access preamble sequence, a cyclic prefix (CP), and a guard time (GT), wherein the random access channel generation method in a mobile communication system having a wide cell area.
Determination unit for determining the size of the cell radius;

When the cell radius determined by the determination unit exceeds a predetermined criterion, the subcarrier spacing of the random access channel is set to 1 / n (n is an integer greater than 1) times the subcarrier spacing of the terrestrial LTE data channel and the terrestrial LTE random access channel. The first setting unit and

And a second setting unit for setting the length of the random access preamble to m (m is an integer greater than 1) times the terrestrial LTE subframe length, thereby generating a random access channel in a mobile communication system having a wide cell area. Device.
The method of claim 3, wherein

The random access preamble includes a random access preamble sequence, a cyclic prefix (CP), and a guard time (GT), the apparatus for generating a random access channel in a mobile communication system having a wide cell area.