KR100626668B1 - Random Access Apparatus Supporting a variety of access service class and Method thereof - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a random access device and a method for supporting various access service levels.

2. The technical problem to be solved by the invention

The present invention provides a random access device capable of performing random access for various purposes without a collision between terminals by configuring a preamble by multiplying a plurality of M-sequences and a Hadamard sequence in a situation where a random access resource is determined in a mobile communication system; The purpose is to provide the method.

3. Summary of Solution to Invention

According to an aspect of the present invention, there is provided a random access device supporting various access service levels, the apparatus comprising: RF transmitting and receiving means for receiving a preamble announcement broadcast signal from a base station and transmitting a preamble to a base station; Guide broadcast signal processing means for extracting a random access use for a plurality of M sequences and Hadamard sequences from the received preamble guide broadcast signal; Selecting means for selecting a plurality of M sequences and Hadamard sequences that match the purpose of random access based on the extracted random access usage; And preamble generating means for generating a preamble from the selected plurality of M sequences and the Hadamard sequence.

4. Important uses of the invention

The present invention is used in a mobile communication system.

M sequence, Hadamard sequence, identifier, random access, access class of service

Description

Random Access Apparatus Supporting a variety of access service class and Method

1 is a configuration diagram of an embodiment of a random access device according to the present invention;

2 is a configuration diagram of an embodiment of a base station preamble processing apparatus;

3 is a diagram illustrating a random access procedure between a random access device and a base station according to the present invention.

* Explanation of symbols for the main parts of the drawings

110: RF transceiver 120: guide broadcast signal processing unit

130: preamble selector 140: preamble generator

141: first M-sequence generation unit 142: second M-sequence generation unit

143: Hadamard sequence generation unit 144: multiplication unit

The present invention relates to a random access device and a method thereof, and more particularly, a random access device capable of supporting various access service levels by performing a random access by configuring a preamble by a product of a plurality of M-sequences and a Hadamard sequence. And to a method thereof.

In a mobile communication system, a terminal randomly uses an access channel to attempt a call with a base station, to report a location when passing through multiple cells, or to respond when called from a base station through a paging channel. Try.

In the third generation mobile communication system, an asynchronous manner in W-CDMA (Wideband-Code Division Multiple Access) standardization organization 3GPP (3 ^rd Generation Partnership Project) in the system of and progress standardization work on the MBMS (Multimedia Broadcast / Multicast Service) .

In addition, IEEE 802.16e is conducting standardization on the Multimedia Multicast / Broadcast Service (MBS), which is a service similar to MBMS of 3GPP.

Then, in the 3GPP2 (3 ^rd Generation Partnership Project2) to develop the EV-DO system and proceed to try to standardize service broadcasting service (Broadcast Multicast System) BCMCS.

As such, the mobile communication system is diversifying the service such as providing a multimedia broadcasting service to the terminal.

Meanwhile, in a W-CDMA system, when a terminal performs a random access request, the access priority is called an access service class (ASC). The access service level of the terminal is classified into eight levels, and the highest priority is set to zero, and the lowest rank is set to seven. In access service class, 0 is used in emergency call such as 119.

A random access channel (RACH) is composed of a preamble and a message. If the terminal transmits the preamble and the base station approves, the terminal sends a message. The terminal transmits the preamble first with low power and then gradually ramps up the power if it is not approved by the base station.

At this time, the preamble consists of a product of a Hadamard code and an M-sequence, and the Hadamard code is called a signature and has 16 types. The reason why the number of signatures is 16 is that when multiple terminals simultaneously perform a random access request, since there is a high probability of collision if only one signature is used, the probability of collision is reduced by setting 16 signature types. On the other hand, the preamble consists of 15 slots for a time of 20 ms (0.02 seconds).

Therefore, when the terminal attempts a random access, the terminal selects one of the possible signatures and 15 slots among the 16 signatures according to the priority and attempts the random access.

If the received preamble code is different, the base station interprets that the terminals transmitting the preamble are different from each other, and grasps the priority of the service attempting random access. However, when different terminals use the same preamble code, a collision occurs and the base station cannot accept the random access intention of the terminal.

As described above, since the W-CDMA system is based on 15 slots and 16 signatures, there is a limitation in varying access service grades. That is, when the access service class is classified into eight classes and only two signatures are used for each service class, only two terminals having the same service class may randomly access one slot.

Since the priorities are different for all the services, in order to differentiate random accesses having different priorities, a random threshold value is provided, and the random access service class is given an opportunity of random access. For each service, a random threshold of random access request opportunity may change over time, with the base station notifying the broadcast.

Meanwhile, in an orthogonal frequency division multiple access (OFDMA) system, a data channel and a random access request channel are separated in time in the random access channel. In conventional IEEE 802.16, a random access request is called ranging. The ranging is divided into initial ranging, periodic ranging, handover ranging, and bandwidth request ranging.

Initial ranging is connection request for initial synchronization acquisition and power control, periodic ranging is connection request for connected terminal to maintain synchronization and power, handover length ranging is connection request for handover, bandwidth request lane A gong is a connection request for a purpose in which a terminal requires a bandwidth.

In this ranging, various sequences generated from one M-sequence PN ³ are used as codes. However, since the arrival time of the signal received by the ranging code varies depending on the distance between the terminal and the base station, the base station cannot analyze the random access ranging M sequence sent by the terminal. To solve this problem, the initial ranging and handover ranging codes are sent twice, and the initial ranging and handover ranging, periodic ranging, and bandwidth ranging codes use different M-sequences. A terminal performing ranging for the same purpose may select and transmit the same sequence among sequences of a given purpose. However, if you choose the same sequence, a collision can occur. The terminal reconnects if a collision occurs.

In the case of the MBS service currently considered by IEEE802.16e, all base stations provide the same broadcast service on the same frequency. However, in the case of the MBMS considered in the W-CDMA cell-based mobile communication system, the base station may inquire about the services that can be provided to various terminals and then inquire whether the terminals in the cell should receive the service. When the base station inquires, the terminal responds with a service reception through a random access.

When a base station capable of various services such as multimedia broadcasting, commerce, distance education, medical care, etc. determines a broadcast channel by inquiring which terminal to receive, the terminal should respond through a random access at a given time. MBMS, which is currently being standardized, should broadcast independent data in each cell, and inquires how many terminals will receive a broadcast for each cell to determine which data channel to use for broadcasting.

When the terminal responds in a situation where the code of the random access preamble is limited, collision of the random access by various terminals occurs, so a method of avoiding collision is needed.

It is difficult to accommodate various services with the random access preamble code discussed in the current standard of mobile communication systems. Accordingly, a random access preamble code that supports various services is requested without increasing the number of random access preamble symbols.

The present invention has been proposed to solve the above problems, and in a situation where a random access resource is determined in a mobile communication system, a preamble is constructed by multiplying a plurality of M-sequences and a Hadamard sequence, thereby randomizing various objects without collision between terminals. It is an object of the present invention to provide a random access device capable of performing a connection and a method thereof.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

An apparatus of the present invention for achieving the above object is a random access device that supports a variety of access service level, RF transmission and reception means for receiving a preamble announcement broadcast signal from the base station, and transmitting the preamble to the base station; Guide broadcast signal processing means for extracting a random access use for a plurality of M sequences and Hadamard sequences from the received preamble guide broadcast signal; Selecting means for selecting a plurality of M sequences and Hadamard sequences that match the purpose of random access based on the extracted random access usage; And preamble generating means for generating a preamble from the selected plurality of M sequences and the Hadamard sequence.

The method of the present invention also provides a random access method comprising: an announcement broadcast receiving step of receiving an announcement broadcast signal relating to a random connection use of a plurality of M sequences and a Hadamard sequence from a base station; A preamble generation step of generating a preamble by selecting a plurality of M sequences and a Hadamard sequence corresponding to a random access purpose according to the random access purpose; A preamble transmission step of transmitting the generated random access preamble to the base station; And a response signal receiving step of receiving a preamble response signal for the random access succession from the base station.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The random access device according to the present invention uses a plurality of M sequences (also called pseudo random (PN) sequences) and a Hadamard sequence for a random access request channel (a preamble in a WCDMA system) And a ranging code), and the base station receives the random access request preamble. The base station checks whether the random access device is in its cell or sector based on the cross correlation of the M sequence and the orthogonality of the Hadamard sequence, and classifies the priority of random access and the class of access service. do.

The following examples consider two M sequences. Therefore, if the code used for the preamble of the random access request channel according to the present invention is defined as RAP (Random Access Preamble), the RAP can be expressed as Equation 1 below.

RAP = PN ₁ * PN ₁₂ * H _N

Here, PN ₁ is a first M-sequence, PN ₂ is a second M-sequence, and H _N is a Hadamard code.

1 is a configuration diagram of an embodiment of a random access device according to the present invention.

As shown in FIG. 1, the random access apparatus according to the present invention includes an RF transceiver 110, an announcement broadcast signal processor 120, a preamble selector 130, and a preamble generator 140.

The RF transceiver 110 receives the preamble announcement broadcast signal from the base station and also transmits the preamble to the base station.

The announcement broadcast signal processor 120 processes the preamble announcement broadcast signal of the base station received through the RF transceiver 110. That is, the purpose of random access to the first M-sequence PN ₁ , the second M-sequence PN ₂ , and the Hadamard sequence H _N is analyzed from the preamble announcement broadcast signal received from the base station.

The preamble selector 130 is the first M-sequence PN ₁ , the second M-sequence PN ₂ , and the like corresponding to the random access purpose according to the random access purpose analyzed by the announcement broadcast signal processor 120. Select the Mad Sequence (H _N ).

The preamble generator 140 generates a first M-sequence PN ₁ , a second M-sequence PN ₂ , and a Hadamard sequence H _N according to the selection in the preamble selector 130. Create a preamble. In this case, the preamble generator 140 includes a first M-sequence generator 141, a second M-sequence generator 142, a Hadamard sequence generator 143, and a multiplier 144.

The first M-sequence generator 141 generates an M-sequence of an n-th order primitive polynomial whose initial value is determined as an identifier 1 of the base station.

The second M-sequence generator 142 generates an M-sequence of the m-th order raw polynomial whose initial value is determined by a random number selected by the terminal and an identifier 2 of the base station. At this time, if necessary, the second M-sequence generation unit 142 may generate the M-sequence only by a random number without using an identifier of the base station.

The Hadamard sequence generating unit 143 generates a sequence consisting of Hadamard. The generated Hadamard sequence expresses the priority of random access and the type of access service.

The multiplier 144 generates a preamble by multiplying the first M-sequence, the second M-sequence, and the Hadamard sequence.

The reason for considering two M-sequences in the present invention is to diversify the identifier of the base station by classifying the identifier for the base station into two identifiers. This is because the number of symbols is determined during a predetermined preamble period, and thus there is a limit to diversifying the identifier with a given number of symbols. In general, in a CDMA system, a preamble has a high power and is transmitted to a base station to interfere with another data channel. Therefore, the number of symbols should be small. In addition, when the number of symbols in the preamble is large in the OFDMA system, the number of symbols should be limited because data cannot be transmitted during the symbol transmission time. That is, in the OFDMA system, as the number of symbols of the preamble for performing random access is smaller, more data can be transmitted, and as the number of symbols of the preamble is larger, more base station identifiers can be transmitted.

In the present invention, by using two M-sequences as described above without increasing the number of symbols in the preamble, the identifier for the base station is classified into two identifiers, thereby diversifying the identifier of the base station.

2 is a configuration diagram of an embodiment of a preamble processing apparatus of a base station.

As shown in FIG. 2, the preamble processing apparatus of the base station includes an RF transceiver 210, an announcement broadcast data processor 220, and a preamble analyzer 230.

The RF transceiver 210 receives a RF signal including a preamble from a random access device to perform signal processing, and further includes a first M-sequence PN ₁ , a second M-sequence PN ₂ , and a Hadamard sequence performing signal processing on the broadcast signal for guiding the random access for the purpose (H _N), and transmits the random access.

The announcement data processing unit 220 selects how to use the first M-sequence PN ₁ , the second M-sequence PN ₂ , and the Hadamard sequence H _N according to the use of the random access in the cell. Produces data for the purpose announcement broadcast and outputs to the RF transceiver 210.

The preamble analyzer 230 analyzes the signal output from the RF transceiver 210 to determine whether the preamble is received from the random access device, and if so, determines the purpose of the random access from the preamble.

3 is a diagram illustrating a random access procedure between a random access device and a base station according to the present invention.

As shown in FIG. 3, first, a base station broadcasts a random access purpose of a first M-sequence, a second M-sequence, and a Hadamard sequence to a random access apparatus (301).

Subsequently, the random access device generates a preamble as shown in Equation 1 (302), and transmits the generated preamble to the base station (303).

At this time, in the case of CDMA (OFDMA), when the number of chips (symbols) in the preamble is larger than the number of chips (symbols) in the Hadamard sequence, the Hadamard sequence is repeatedly transmitted so that the diversity gain is large. That is, when the number of chips (symbols) in the Hadamard sequence is small, first, the Hadamard sequence is multiplied by the M-sequence, and the remaining M- sequence and the Hadamard sequence are repeatedly multiplied and transmitted.

In the case of CDMA (OFDMA), when the number of chips (symbols) in the preamble is larger than the number of chips (symbols) in one M-sequence of the first M-sequence and the second M-sequence, The M-sequences are repeatedly transmitted so that the diversity gain is large.

Subsequently, the base station determines whether the random access device is a random access device in its own cell or sector by using the cross-correlation function of the M-sequence included in the received preamble and the orthogonality of the Hadamard sequence, Access class of service is identified and classified (304).

The base station transmits a random access preamble response signal to the random access device (305).

The process 302 will now be described in detail as follows.

First, when 96 symbols are used as symbols of a preamble in an OFDMA system, in a state in which a base station has no information on synchronization and power of a random access device, the random access device may transmit 96 symbols twice. When there is information on the synchronization and power of the random access device, the random access device may transmit 96 symbols only once.

If the 96 preamble symbols are RAP _k (k = 0 to 95), respectively, RAP _k can be expressed as follows.

RAP _k = PN _1k * PN _2k * H ₁₆ , _{k% 16}

Here, PN _1k is an M-sequence of P ₁ = 1 + X ³ + X ¹⁰ , where identifier 1 is a cell group number, and an initial value is a result of multiplying the cell group number by 8. The sequence of occurrences is multiplied by -2 and one added to it. If this is expressed in detail as shown in [Equation 3].

PN _2k is an M-sequence of P ₂ = 1 + X ³ + X ⁷ , with identifier 2 as the cell group number, the initial value multiplied by the cell group number 8, and the resulting value plus any number The sequence of occurrences is multiplied by -2 and one added to it. At this time, the arbitrary number is limited to an integer from 0 to 15. If this is expressed in detail as shown in [Equation 4].

, 여기서 RACN(Random Access Code Number)은 랜덤 접속 코드 수로서, 기지국이 서비스마다 그 용도를 정하여 랜덤 접속 장치에 그 사용 방법을 알려 줄 수 있다.

Here, RACN (Random Access Code Number) is the number of random access codes, the base station can determine the use for each service and can inform the random access device how to use.

H ₁₆ , _{k% 16} is a Hadamard sequence that transmits 16 symbols repeatedly six times. Since the Hadamard sequence is orthogonal, the base station can distinguish a random access device using PN _1k and PN _2k that are different from each other.

For example, the Hadamard sequence H ₀ is used for emergency calls and equivalent priority services, H ₁ is used for initial synchronization and power control, and H ₂ is used as the random access device moves. When the cell is changed, it is used to report that the cell has been changed to the base station, H ₃ is used as a response to paging for the downlink data call, H ₄ is used to request a data call on the uplink, H _{5 to} H ₁₅ are used for indicating whether or not to receive a broadcast service guided by a base station.

Since the priorities are different for all services, in order to differentiate random accesses having different priorities, the base station provides an opportunity for random access by the type of Hadamard sequence (signature) used and the random threshold value. . In this case, when the priority is large enough and the expression is insufficient due to the Hadamard sequence and the random threshold value, the priority may be expressed using the number of random access codes (RACN) included in the M-sequence.

On the other hand, in the case of using 4096 chip preambles in the CDMA system, in Equation 2, k is 0 to 4095, and PN _1k creates a sequence by inserting an identifier 1 for each sector and multiplies the sequence by -2. PN _2k is a sequence of ones plus one, multiplying -2 by a number based on a unique random number selected by the random access device, and adding one.

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, in the situation that the random access resources are determined in the mobile communication system, by varying the random access request preamble, there is an effect that can support a variety of services without collision between terminals.

Claims (12)

As a random access device that supports various access service levels, RF transmission and reception means for receiving a preamble announcement broadcast signal from a base station and transmitting a preamble to the base station; Guide broadcast signal processing means for extracting a random access use for a plurality of M sequences and Hadamard sequences from the received preamble guide broadcast signal; Selecting means for selecting a plurality of M sequences and Hadamard sequences that match the purpose of random access based on the extracted random access usage; And Preamble generating means for generating a preamble from the selected plurality of M sequences and Hadamard sequences Random access device comprising a. The method of claim 1, The preamble generating means, A first M sequence generator generating an M sequence whose initial value is determined as an identifier 1 of the base station; A second M sequence generator generating an M sequence whose initial value is determined by a random number; A Hadamard sequence generation unit for generating a sequence consisting of Hadamard representing a type of random access service; And A multiplier for generating a preamble by multiplying the first M sequence, the second M sequence, and the Hadamard sequence Random access device comprising a. The method of claim 2, The second M sequence generating unit, And a sequence of M whose initial value is determined by an identifier 2 of the base station and a random number. The method of claim 2 or 3, The Hadamard sequence, A random access device, characterized in that it represents a type of random service, and the priority of the service by a random threshold value. The method of claim 2 or 3, A random access device, characterized by expressing the priority of the random access service using the number of random access codes (RACN) included in the M sequence. As a random connection method, An announcement broadcast receiving step of receiving an announcement broadcast signal relating to a random access purpose of a plurality of M sequences and a Hadamard sequence from a base station; A preamble generation step of generating a preamble by selecting a plurality of M sequences and a Hadamard sequence corresponding to a random access purpose according to the random access purpose; A preamble transmission step of transmitting the generated random access preamble to the base station; And A response signal receiving step of receiving a preamble response signal from the base station for the random access success Random access method comprising a. The method of claim 6, The preamble generation step, The preamble is generated by selecting two M sequences and a Hadamard sequence that match the purpose of random access according to the random access purpose, wherein the first M sequence is determined as an identifier 1 of the base station, and the second M sequence is an initial sequence. The random access method, characterized in that the value is determined by a random number. The method of claim 7, wherein The second M sequence is, The random access method, characterized in that the initial value is determined by the identifier 2 and the random number of the base station. The method according to claim 7 or 8, The Hadamard sequence, A random access method, characterized in that it represents a type of random service, and the priority of the service by a random threshold value. The method according to claim 7 or 8, A random access method characterized by expressing the priority of the random access service using the random access code number (RACN) included in the M sequence. The method according to claim 7 or 8, If the number of chips (symbols) in the preamble is greater than the number of chips (symbols) in the Hadamard sequence, repeatedly transmitting the Hadamard sequence so that the diversity gain is large Random access method further comprising. The method according to claim 7 or 8, If the number of chips (symbols) in the preamble is larger than the number of chips (symbols) in any one of the plurality of M sequences, repeatedly transmitting M sequences having a small number of chips (symbols) so that the diversity gain is large. Random access method further comprising.

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