KR20090040119A - Method for performing ranging procedure - Google Patents

Abstract

A method for performing a ranging process for delivering the status information of a terminal to a base station in a ranging process is provided to manage resource efficiently by efficiently performing a process such as resource allocation. A UE(User Equipment) reads a DL-MAP message transmitted from a BS(Base Station)(S110). A ranging code is transmitted from the terminal in order to attempt the initial ranging(S130). After the ranging response message is received, an RNG-REQ(Ranging Request) message including its own unique identifier is sent to the terminal(S160). The terminal and base station perform the authentication.

Description

Method for performing ranging procedure

The present invention relates to wireless communication, and more particularly, to a method of informing a terminal of a terminal information to a base station during a ranging process.

The Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard provides technologies and protocols to support broadband wireless access. Standardization has been in progress since 1999, and IEEE 802.16-2001 was approved in 2001. This is based on a single carrier physical layer called 'WirelessMAN-SC'. Later, in the IEEE 802.16a standard approved in 2003, 'WirelessMAN-OFDM' and 'WirelessMAN-OFDMA' were added to the physical layer in addition to 'WirelssMAN-SC'. After the completion of the IEEE 802.16a standard, the revised IEEE 802.16-2004 standard was approved in 2004. In order to correct bugs and errors in the IEEE 802.16-2004 standard, IEEE 802.16-2004 / Cor1 was completed in 2005 in the form of 'corrigendum'.

In order to receive and demodulate data in a wireless communication system, a task of synchronizing a receiver and a transmitter is required. In particular, in a mobile communication system in which the channel environment between the base station and the terminal is constantly changing, synchronization is required through close signaling between the base station and the terminal for successful transmission and reception of data.

The communication channel between the base station and the terminal is largely composed of a downlink channel from the base station to the terminal and an uplink channel from the terminal to the base station. In downlink, a plurality of terminals synchronize downlink synchronization with data frames transmitted from a base station in a point-to-multipoint situation. As a way to allow the terminals to synchronize, the base station may insert a preamble for synchronization into a part of a frame to be transmitted. The UEs synchronize synchronization with the downlink channel through the preamble. Alternatively, the base station may use a separate synchronization channel.

In the uplink, each terminal must transmit data to the base station through a time and / or frequency domain allocated to the terminal so that the base station can receive the data while avoiding interference between the terminals. Accordingly, for uplink synchronization, it is necessary to adjust synchronization through signaling between the base station and the terminal in consideration of the channel environment of each terminal.

In the IEEE 802.16 standard, a signal transmitted and received between a terminal and a base station for uplink synchronization is called a ranging signal. The ranging process is a series of processes for adjusting transmission power and synchronizing time / frequency synchronization through a process in which a ranging signal is exchanged between a terminal and a base station. A series of processes for obtaining uplink synchronization may be referred to as ranging processes.

Initial ranging is a process of obtaining an accurate timing offset between a terminal and a base station and initially adjusting transmission power. When the power is turned on, the terminal obtains downlink synchronization from the received downlink preamble signal. Subsequently, the terminal performs initial ranging to adjust uplink timing offset and transmission power. Unlike initial ranging, periodic ranging is a process of periodically tracking uplink timing offset and received signal strength after initial ranging.

When attempting the ranging process, a predetermined ranging code is used as the ranging signal. However, in order to obtain uplink synchronization, the base station needs to know specific information of the terminal. Depending on whether the terminal can support the uplink resource and the downlink resource ratio, location, resource allocation, etc. should be allocated differently.

There is a need for a method for allowing a base station to know information about a state of a terminal during a ranging process.

An object of the present invention is to provide a method for the terminal to inform the base station of the terminal information during the ranging process.

In one aspect, a method for performing a ranging process for obtaining uplink synchronization is provided. The method includes transmitting a ranging code over a ranging slot and receiving a ranging response message in response to the ranging code. The ranging code includes state information of a terminal performing the ranging process.

In another aspect, a base station provides a method for performing a ranging process for adjusting a time or frequency offset required for uplink transmission from a terminal. The method includes receiving a ranging code including status information of the terminal and transmitting a ranging response message including confirmation of the status information of the terminal in response to the ranging code.

The state information of the terminal may be transmitted to the base station during the ranging process. The base station can process resources such as resource allocation during the ranging process through state information of the terminal, thereby enabling more efficient resource management.

1 is a block diagram illustrating a wireless communication system. Wireless communication systems are widely deployed to provide various communication services such as voice and packet data.

Referring to FIG. 1, a wireless communication system includes a user equipment (UE) 10 and a base station 20 (BS). The terminal 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), and a wireless device. The base station 20 generally refers to a fixed station for communicating with the terminal 10 and may be referred to in other terms such as a NodeB, a base transceiver system (BTS), and an access point. . One or more cells may exist in one base station 20.

The wireless communication system may be an Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) based system. OFDM uses multiple orthogonal subcarriers. OFDM uses orthogonality between inverse fast fourier transforms (IFFTs) and fast fourier transforms (FFTs). At the transmitter, data is sent by performing an IFFT. The receiver performs FFT on the received signal to recover the original data. The transmitter uses an IFFT to combine multiple subcarriers, and the receiver uses a corresponding FFT to separate multiple subcarriers.

2 shows an example of a frame structure. A frame is a sequence of data for a fixed time used by physical specifications. This can be found in section 8.4.4.2 of the IEEE standard 802.16-2004 "Part 16: Air Interface for Fixed Broadband Wireless Access Systems" (hereafter reference 1).

Referring to FIG. 2, the frame includes a downlink (DL) frame and an uplink (UL) frame. Time Division Duplex (TDD) is a method in which uplink and downlink transmissions share the same frequency but occur at different times. The downlink frame is temporally ahead of the uplink frame. The downlink frame starts with a preamble, a frame control header (FCH), a downlink (DL) -MAP, an uplink (MAP) -MAP, and a burst region. A guard time for distinguishing the uplink frame and the downlink frame is inserted in the middle part (between the downlink frame and the uplink frame) and the last part (after the uplink frame) of the frame. A transmit / receive transition gap (TGT) is a gap between a downlink burst and a subsequent uplink burst. A receive / transmit transition gap (RTG) is a gap between an uplink burst and a subsequent downlink burst.

The preamble is used for initial synchronization, cell search, frequency offset, and channel estimation between the base station and the terminal. The FCH includes the length of the DL-MAP message and the coding scheme information of the DL-MAP.

DL-MAP is an area where a DL-MAP message is transmitted. The DL-MAP message defines the connection of the downlink channel. The DL-MAP message includes a configuration change count of the downlink channel descriptor (DDC) and a base station identifier (ID). DCD describes a downlink burst profile applied to the current map. The downlink burst profile refers to the characteristics of the downlink physical channel, the DCD is periodically transmitted by the base station through the DCD message.

The UL-MAP is an area in which the UL-MAP message is transmitted. The UL-MAP message defines the access of an uplink channel. The UL-MAP message includes a configuration change count of an uplink channel descriptor (UCD) and a valid start time of uplink allocation defined by UL-MAP. UCD describes an uplink burst profile. The uplink burst profile refers to characteristics of an uplink physical channel, and the UCD is periodically transmitted by the base station through a UCD message.

In the following, a slot is defined as the minimum possible data allocation unit, time and subchannel. The number of subchannels depends on the FFT size and the time-frequency mapping. The subchannel includes a plurality of subcarriers, and the number of subcarriers per subchannel depends on a permutation scheme. Permutation means mapping logical subchannels to physical subcarriers. In FUSC (Full Usage of Subchannels), a subchannel includes 48 subcarriers, and in Partial Usage of Subchannels (PUSC), a subchannel includes 24 or 16 subcarriers. A segment refers to at least one subchannel set. The bin includes 9 contiguous subcarriers on the OFDM symbol. A band refers to a group of four rows of bins, and an adaptive modulation and coding (AMC) subchannel consists of six contiguous bins in the same band.

3 is an exemplary diagram illustrating an FDD mode and an H-FDD mode.

Referring to FIG. 3, in the frequency division duplex (FDD) mode, uplink transmission and downlink transmission are performed in different frequency bands. In half-frequency division duplex (H-FDD) mode, although uplink transmission and downlink transmission are performed in different frequency bands, one UE performs uplink transmission and downlink transmission at different times. That is, in the H-FDD mode, the UE cannot simultaneously perform uplink transmission and downlink transmission.

4 is a flowchart illustrating a network initialization process according to an embodiment of the present invention. The network initialization refers to a process in which a terminal initially enters a network, and initial ranging is a process of obtaining an accurate timing offset between the terminal and a base station and initially adjusting transmission power.

4, the terminal reads the DL-MAP message transmitted from the base station (S110). For initialization or after losing the signal, the terminal should obtain the downlink channel. The terminal scans a radio channel, receives a frame structure, and synchronizes with the base station. When the terminal receives at least one DL-MAP message, it may obtain MAC (Medium Access Control) synchronization. Upon obtaining MAC synchronization, the terminal can continue to receive DL-MAP message, DCD message and UCD message. After synchronization, the terminal waits for a UCD message from the base station and obtains transmission parameters for possible uplink channels. The UCD message includes the time and frequency to send the ranging request. The UCD message may specify one or more groups of 6 (or 8) contiguous subchannels where contention based ranging is performed. The contention-based means that at least one terminal may transmit on the same subchannel at the same time.

In order to find an initial ranging interval, the UE reads a UL-MAP message (S120). The base station allocates an initial ranging interval consisting of at least one transmission opportunity. The transmission opportunity refers to an allocation provided by UL-MAP so that a certain group of authorized terminals can transmit an initial ranging request.

The terminal transmits a ranging code to attempt initial ranging (S130). The ranging code is sent from the terminal at initialization to determine the network delay and to request a power and / or downlink burst profile change. The terminal randomly selects a ranging slot within a backoff window included in the UCD. The ranging code randomly selects a Code Division Multiple Access (CDMA) code from a series of allowed codes. The ranging code may use a pseudo-random bit sequence (PRBS) coded binary phase shift keying (BPSK) code. The ranging code is transmitted through the selected ranging slot. The ranging code sent initially is called an initial ranging code.

5 shows an example of a PRBS generator.

Referring to FIG. 5, it implements a polynomial generator 1 + X ¹ + X ⁴ + X ⁷ + X ¹⁵ , and the sequence represented by the output Ck becomes a ranging code. 256 orthogonal codes of 144 bits in length generated by the PRBS generator are used for initial ranging, handover ranging, periodic ranging, and bandwidth request. Each is divided into The terminal randomly selects one code among 256 code codes belonging to the ranging purpose performed by the terminal.

The 144-bit ranging code is modulated onto subcarriers belonging to a group of 6 (or 8) subchannels. The plurality of subchannels to which the ranging code is modulated are called ranging subchannels.

6 shows an OFDM symbol structure used for a ranging code for initial ranging and handover ranging. Initial ranging transmission and handover ranging transmission are performed during two consecutive OFDM symbols. The same ranging code is transmitted on the ranging subchannel for each OFDM symbol. This structure may be repeated to transmit a ranging code for 4 OFDM symbols. When using repeated structures, different sequences may be used for each repeated basic structural unit. It is also possible to use sequences of sequential indexes.

7 shows an OFDM symbol structure used for a ranging code for periodic ranging and bandwidth request. The ranging code is transmitted on the ranging subchannel during one OFDM symbol. This structure may be repeated three times to transmit a ranging code for three OFDM symbols. When using repeated structures, different sequences may be used for each repeated basic structural unit. It is also possible to use sequences of sequential indexes.

Referring to FIG. 4 again, the base station sends a ranging response (RNG-RSP) message in response to the ranging code (S145). When the base station receives the ranging code, the base station transmits time / frequency offset information along with the received ranging code index and ranging slot number in the ranging response message. Since the base station does not know which terminal has sent a ranging code, it designates a CDMA code and a ranging slot to allow the terminal to identify itself through the ranging slot.

The ranging response message is a broadcast message. Through ranging, the base station determines symbol timing offset due to transmission delay, frequency offset due to Doppler shift or oscillator inaccuracy, and reception power. Using this information, the base station sends a calibration to the terminal. The terminal continues ranging until the power, timing and frequency are aligned.

The ranging response message includes ranging status information. If the ranging status is 'continue', the terminal performs the calibration specified in the ranging response message although the transmission attempt is not successful, and registers another CDMA code after an appropriate backoff delay.

If the ranging status of the received ranging response message is 'continue', the terminal continues to send the ranging code (S150). The terminal updates the timing and power specified in the ranging response message and sends a ranging request message. Through the ranging response message, the terminal confirms that the base station has received the ranging code sent by the base station, adjusts transmission power based on the information contained in the ranging response message, and adjusts time / frequency synchronization.

If the ranging state of the ranging response message is 'continued', the UE obtains information on periodic ranging from the CDMA initial ranging IE. One of the periodic ranging slots is randomly selected and transmitted using the CDMA code used for the previous initial ranging.

The base station transmits a ranging response message in which the ranging state is 'success' (S155). The base station continues further fine tuning via the ranging response message. The ranging request / response steps are repeated until the base station sends a ranging response message including ranging success or ranging abort.

After receiving the ranging response message having the ranging status 'success', the terminal sends a ranging request (RNG-REQ) message including its own unique identifier (S160). Since the ranging process is a contention-based process, when ranging is successfully performed, an identifier for identifying a corresponding terminal is required. The unique identifier may be, for example, a medium access control (MAC) address. The MAC address is a unique identifier assigned at the manufacturing stage and used for identification of the terminal.

The base station transmits the ranging response message including the primary management primary identification CID (S165). A connection identifier (CID) refers to a value for confirming a connection between a base station and a terminal's MAC, and a primary management CID is established during initial ranging to transmit a delay-tolerant medium access control (MAC) message. CID for the connection used.

The base station and the terminal negotiate a basic capability (S170). Immediately after the ranging is completed, the terminal transmits a Basic Capability Request (SBC-REQ) message including its basic capability. The basic capability of the provided terminal is whether to support ARQ (Automatic Repeat Request) or MAC level CRC (Cyclic Redundancy Check). In response to the basic capability request message, the base station sends a Basic Capability Response (SBC-RSP) message.

The terminal and the base station authenticate each other, and exchange an authorization key (S175).

The terminal sends a registration request (REG-REQ) message (S180). The registration request message includes the primary management CID.

The base station sends a registration response (REG-RSP) message in response to the registration request message (S185). The registration response message includes a secondary management CID. The secondary management CID is the CID for the connection established during terminal registration and used to send standards-based messages such as Simple Network Management Protocol (SNMP) or Dynamic Host Configuration Protocol (DHCP).

After registration is made, IP connectivity is established, a time of day is established, and other operating parameters are transmitted. This sets up the connection.

In the network initialization process as described above, specific information of the terminal may be transmitted in the ranging process before the basic capability is negotiated. For example, when the FDD mode and the H-FDD mode are used at the same time, information on whether the UE supports FDD or only H-FDD should be transmitted during the ranging process. Location, resource allocation, power balancing, and the like.

In the current IEEE 802.16 standard, the base station cannot know information about the state of the terminal during the ranging process. Depending on whether the terminal supports the FDD mode or the H-FDD mode, the base station should be able to set the radio resource allocation method differently, thereby enabling efficient use of radio resources of the system. In particular, in a situation in which the transmission and / or reception of the UE is restricted compared to the FDD mode such as the H-FDD mode, the UE of the H-FDD mode is concentrated in a specific area with respect to the divided downlink / uplink pair. To overcome this phenomenon, effective load balancing is required from the network initialization stage.

Therefore, the UE transmits information on the FDD mode or the H-FDD mode during the initial ranging process, so that the base station can efficiently utilize radio resources, and in advance to increase the latency in system access. It can be prevented.

Hereinafter, a method of transmitting a state of a terminal to a base station during a ranging process is provided. The state information of the terminal refers to various control information that the base station needs to know during the ranging process to allocate radio resources to the terminal, such as whether the H-FDD mode is supported or whether the FDD mode is supported.

First Example

When the total length of the sequence used for the ranging code is x, a part of the sequence is used to transmit the state of the terminal. One or more regions of length y of length x are used to transmit terminal state information, and the remaining length x-y sequences are used as ranging codes.

The sequence can be generated x-y from the beginning, or it can be created with length x to cut and use the length y. The part whose length y is cut off can be any part of the sequence before, after, or in the middle. In addition, y may not be adjacent. For example, a 143 length sequence of the 144 length sequences is used as a ranging code, and the last one bit is used to convey status information of the terminal. The terminal supporting the FDD mode transmits '0', and the terminal supporting the H-FDD mode transmits '1'.

The base station uses the x-y length sequence for ranging code detection. When the ranging code is detected, channel estimation may be performed on a time / frequency position around a bit including state information using the detected sequence. When using the AMC mode, it is possible to estimate a channel using several adjacent subcarriers. When used in the PUSC mode, multiple tiles are not adjacent to each other in the frequency domain, but since four subcarriers are adjacent to each other in the frequency domain, a channel may be estimated using 4-y subcarriers. have. Alternatively, the channel may be estimated using only one adjacent subcarrier. After performing channel compensation with the estimated channel value, it is possible to detect the transmitted information.

 Using this method, the length of the sequence used for the ranging code is reduced, but the difference in detection performance is not so large. In the above example, the length of a sequence is reduced by one and the state information of the terminal is transmitted as an example. However, the length of the sequence used for transmitting the state information of the terminal is not limited. In addition, the state information of the UE may be modulated and transmitted in quadrature phase shift keying (QPSK), quadrature amplitude modulation (4-QAM), 16-QAM, 64-QAM, etc. in addition to binary phase shift keying (BPSK). When using a higher order modulation scheme, the state information of several terminals may be transmitted at once, and the state information of the terminals may be repeatedly transmitted. In order to reduce the detection error, the subcarrier including the state information of the terminal may be power boosted and transmitted.

Initial ranging channel (initial ranging channel) is uplink synchronization, and is also important as a channel that the terminal is the first access to the base station. In order to prevent performance of the initial ranging channel, the base station receives the ranging response message including the status 'continued' in response to the initial ranging channel, and then the terminal transmits the status information of the terminal through the periodic ranging channel. Can be.

2nd Example

The ranging code itself may be allocated separately according to the state information of the terminal. For example, if there are a total of N ranging codes, they are divided into groups according to state information of the terminal. According to the state of each terminal, the terminal selects and transmits the ranging code in the allocated state information group.

For example, if there are N initial ranging codes, divided into two parts, K initial ranging codes support FDD mode, and the remaining NK initial ranging codes represent H-FDD mode support. . When the UE supports the FDD mode, the UE randomly selects and transmits K initial ranging codes. When the terminal supports the H-FDD mode, the UE randomly selects and transmits N-K initial ranging codes.

The base station detects the received signal and knows the state of the terminal according to which group of codes. The division by the above code may use not only an initial ranging code but also a periodic ranging code or a bandwidth request ranging code.

3rd Example

Referring to IEEE 802.16-2004 / Cor1 section 8.4.7.3, ranging codes are divided according to the use such as initial ranging code, periodic ranging code, bandwidth request ranging code, and HO (Handover) ranging code. In order to transmit the state information of the terminal, the ranging code, which is classified for other purposes, may be reused.

For example, a terminal supporting the FDD mode normally performs initial ranging using an initial ranging code. A terminal supporting the H-FDD mode performs initial ranging using a periodic ranging code. You can use initial ranging. If the status of the ranging response message is 'continued', the UE supporting the H-FDD mode may attempt to periodically ranging the initial ranging code corresponding to the periodic ranging code used by the UE according to a predetermined mapping relationship. have.

As another example, all terminals may initially use an initial ranging code and may transmit status information of the terminal when the ranging response message is 'continued'. A UE supporting the FDD mode performs periodic ranging through an initial ranging code, and a UE supporting the H-FDD mode performs periodic ranging through a HO ranging code. In this case, when the number of initial ranging codes is different from that of other ranging codes, one-to-many mapping relation may be set in advance.

4th Example

A cyclic shift of an initial ranging code may be used to transmit state information of the terminal. When the terminal supports the FDD mode, the terminal initially transmits an arbitrarily selected initial ranging code. When the terminal supports the H-FDD mode, the randomly selected initial ranging code is cyclically shifted by a predetermined specific length (for example, 144/2 = 72) and transmitted. The base station can know the state information of each terminal according to the position where the peak (peak) of the ranging code is detected. If the round trip delay of the cell is smaller than the length of the cyclic shift, the state information of the terminal may be transmitted without affecting the overall performance of the system.

5th Example

In order to transmit the state information of the terminal, a correlation characteristic of a code may be used. The phase of the ranging code may be converted to transmit state information of the terminal. For example, a terminal supporting the FDD mode transmits a ranging code as it is, and a terminal supporting the H-FDD mode multiplies the ranging code by -1.

The base station first detects the ranging code as an absolute value. The reason why the absolute value is used is that the sign of the ranging code itself can be changed by the influence of the channel. After the base station detects the ranging code, the channel can be estimated using the detected ranging code as a reference signal. After the channel value is compensated in the received signal using the estimated channel, the correlation is recalculated without an absolute value. In this case, it may be determined whether the transmitted terminal supports the FDD mode or the H-FDD mode according to whether the sign of the peak value is positive or negative. The base station needs correlation calculation only when the state information of the terminal is needed. The base station that does not need the state information of the terminal does not need correlation calculation.

6th Example

The terminal may transmit state information of the terminal through a medium access control (MAC) message. When the ranging response state is 'success', the terminal may transmit the ranging request message including the status information of the terminal.

The above embodiments are related to a method of transmitting, by a terminal, its own state information to a base station in a ranging process. Hereinafter, a description will be given of a method for the base station confirming the status information of the transmitted terminal.

The confirmation information may be transmitted to the terminal through a ranging response message. In the ranging process, state information of the terminal detected by the base station may be transmitted to the terminal through a ranging response message. If the state information of the terminal indicated in the received ranging response message is not correct, the terminal may additionally transmit the notification of the state information or newly perform the ranging process. For example, if the received status information is not correct, even if the status of the ranging response message is 'success', the ranging request message is transmitted again using the previous ranging code. When the base station receives the ranging request message including the previous ranging code, the base station recognizes that the state information of the existing terminal is incorrectly corrected and corrects it. For another example, the terminal may inform the base station that its state is wrong through the periodic ranging slot using the HO ranging code. In this case, the initial ranging code and the HO ranging code may have a predetermined relationship. Since the initial ranging code and the HO ranging code are different from each other, the base station can distinguish the purpose according to the detected ranging code.

In addition, when the state information of the terminal cannot be transmitted through the initial ranging code, it is necessary to transmit the state information of the terminal before and after the transmission of the ranging response message. The state information of the terminal may be transmitted using code and slot information used in the existing ranging process, and the state information of the terminal may be transmitted in a new form. When the status information of the terminal is transmitted, the ranging response message may include confirmation of the status information.

In the above examples, the state information of the terminal may be transmitted once in an initial ranging, periodic ranging, etc. step, and may be transmitted several times. For example, when the initial ranging may transmit the status information of the terminal to the base station, and if the status of the ranging response message is 'continuous', the error may be reduced by delivering the status information of the terminal once again in the periodic ranging. In addition, after receiving the confirmation information through the ranging response message, the terminal may transmit the status information of the terminal once again through the ranging request message. The method of transmitting the state information of the terminal in each step may be the same or different.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is a block diagram illustrating a wireless communication system.

2 shows an example of a frame structure.

3 is an exemplary diagram illustrating an FDD mode and an H-FDD mode.

4 is a flowchart illustrating a network initialization process according to an embodiment of the present invention.

5 shows an example of a PRBS generator.

6 shows an OFDM symbol structure used for a ranging code for initial ranging and handover ranging.

7 shows an OFDM symbol structure used for a ranging code for periodic ranging and bandwidth request.

Claims (7)

In a method for performing a ranging process for obtaining uplink synchronization, Transmitting a ranging code through a ranging slot; And And receiving a ranging response message in response to the ranging code, wherein the ranging code includes state information of a terminal performing the ranging process. The method of claim 1, The state information is represented through a portion of a sequence used in the ranging code. The method of claim 1, The state information is classified according to the ranging code. The method of claim 1, The ranging slot is a periodic ranging slot. The method of claim 1, The state information is classified according to the correlation characteristics of the ranging code. The method of claim 1, And the ranging response message includes a confirmation regarding the status information. In the method for the base station performs a ranging process for adjusting the time or frequency offset required for uplink transmission from the terminal, Receiving a ranging code including state information of a terminal; And And transmitting a ranging response message including confirmation of the state information of the terminal in response to the ranging code.

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