KR20090087387A - Method and apparatus for the transmission and reception of data in a mobile communication system using enhance random access channel - Google Patents

Abstract

A data transceiving apparatus using an improved random access channel in a mobile communication system and a method thereof are provided to define the transmission format of an E-AGCH to improve an E-RACH(Enhanced Random Access Channel) transmission procedure and the related E-RACH transmission procedure. A base station determines whether a preamble which a mobile station transmits is received without the error(704). If so, an E-AICH(Enhanced-Acquisition Indicator Channel) corresponding to the preamble is generated through information included in the preamble and then is transmitted to the mobile station(706). The base station receives a power control preamble from the terminal, performs the power control for the mobile station and then receives data transmitted from the mobile station(708,710).

Description

METHOD AND APPARATUS FOR THE TRANSMISSION AND RECEPTION OF DATA IN A MOBILE COMMUNICATION SYSTEM USING ENHANCE RANDOM ACCESS CHANNEL}

The present invention relates to an apparatus and method for transmitting and receiving data in a mobile communication system, and more particularly, to an apparatus and method for transmitting and receiving data in a mobile communication system using an enhanced uplink dedicated transport channel (E-RACH). .

1. UMTS system

Based on Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), a European-style mobile communication system, and using Wideband Code Division Multiple Access (CDMA). UMTS (Universal Mobile Telecommunication Service), a third-generation mobile telecommunications system, provides mobile phone and computer users with high-speed transmission of packet-based text, digitalized voice, video, and multimedia data anywhere in the world. .

2. E-DCH

In particular, in the UMTS system, the uplink from the user equipment (UE) to the base station (BS, Node B), that is, the uplink (uplink: UL) communication in order to further improve the performance of packet transmission in uplink (UL) communication A transport channel called an enhanced uplink dedicated channel (E-DCH) is used. In order to support more stable high-speed data transmission, the E-DCH may include adaptive modulation and coding (AMC), hybrid automatic retransmission request (HARQ), base station control scheduling, and short TTI ( Shorter Transmission Time Interval).

3. Uplink packet transmission through E-DCH

(1) Basic Concept of E-DCH

Hereinafter, a description will be given of a concept in which a UE transmits an uplink packet to an eNB through an E-DCH.

1 is a conceptual diagram illustrating uplink packet transmission through an E-DCH in a general wireless communication system.

Reference numeral 100 denotes a base station that supports the E-DCH, that is, Node B. In a UMTS system, a base station is commonly referred to as a Node B. Hereinafter, Node B is used interchangeably with the same meaning as a base station. Reference numerals 101, 102, 103, and 104 denote terminals using the E-DCH. As shown, the terminals 101 to 104 transmit data to the base station 100 through the E-DCHs 111, 112, 113, and 114, respectively.

The base station 100 collects data buffer status, request data rate or channel status information from the terminals 101 to 104 using the E-DCH, and whether the E-DCH data transmission of each terminal is possible and the E of each terminal. A scheduling operation for determining a data rate of the DCH is performed, and a scheduling command according to the result of the scheduling operation is transmitted to each terminal.

(2) scheduling

The scheduling operation is performed by the base station far away from the base station while the noise increase (noise rise or rise over thermal, referred to as "RoT") value measured by the base station does not exceed the target value (for example, to increase the performance of the entire system). The low data rate is allocated to 103 and 104, and the high data rate is allocated to nearby terminals (eg, 101 and 102). The terminals 101 to 104 determine the maximum allowable data rate of the E-DCH data allocated to the terminal according to the scheduling information, and the E-DCH data rate according to the data buffer state within the range of the maximum allowable data rate. Determine and transmit the E-DCH data to the base station.

(3) Restrictions on Scheduling

In uplink, since uplink signals transmitted from different terminals are not orthogonal to each other, the uplink signals act as interference between the terminals. As a result, as the uplink signals received by the base station increase, the amount of interference with respect to the uplink signal of the specific terminal also increases, thereby deteriorating the reception performance of the base station with respect to the uplink signal of the specific terminal. In order to overcome this problem, although the uplink transmission power of the specific terminal may be increased, this may cause interference to the uplink signal received by the base station from another terminal, thereby reducing reception performance. For this reason, the total power of the uplink signal that can be received by the base station is limited to a certain level while ensuring the reception performance of the base station to a certain level or more.

(4) RoT

The rise over thermal (RoT) value described above will be described in detail. The RoT value represents a radio resource used by the base station in the uplink, and is defined as in Equation 1 below.

RoT = I _o / N ₀

, I _o is the power spectral density for the entire reception band of the base station and represents the total amount of uplink signals received by the base station,

, N ₀ represents the thermal noise power spectral density of the base station.

As described above, the maximum RoT allowed by the base station is limited to a predetermined value or less. Therefore, the RoT value means the total radio resources available to the base station in the uplink.

(5) base station control scheduling

The total RoT of the base station is represented by the sum of inter-cell interference, voice traffic, and E-DCH traffic. If base station control scheduling is used, it is possible to prevent a plurality of terminals from transmitting packets of a high data rate at the same time, thereby ensuring reception performance by maintaining a reception RoT of signals currently received as a target RoT.

That is, according to the base station control scheduling, when the base station allows a high data rate for a specific terminal, it does not allow a high data rate for other terminals, thereby preventing the receiving RoT from increasing to more than a target RoT and deteriorating system performance. .

4. Data transmission and reception between the base station and the terminal through the E-DCH

Hereinafter, a process of transmitting data to the base station through the E-DCH in more detail. 2 is a flowchart illustrating a transmission and reception procedure through a typical E-DCH.

In step 202, the base station and the terminal configure the E-DCH. If the E-DCH is configured, the UE informs the base station of the scheduling information in step 204. The scheduling information may include terminal transmission power information indicating uplink channel information, extra power information that can be transmitted by the terminal, and an amount of data to be transmitted in a buffer of the terminal.

In step 206, the base station which has received scheduling information from the plurality of terminals in communication monitors the scheduling information of the plurality of terminals in order to schedule data transmission of each terminal. In detail, in step 208, the base station determines to allow uplink packet transmission to the terminal and transmits a scheduling command to the terminal. The scheduling command indicates an increase / maintenance / decrease of the maximum data rate to the UE through an E-RGCH (E-DCH Relative Grant Channel), or the maximum data rate through an E-AGCH (E-DCH Absolute Grant Channel). Information such as a transmission time can be indicated.

The terminal determines the transport format (TF) of the E-DCH to be transmitted in the uplink using the scheduling command in step 210, and transmits uplink packet data through the E-DCH in steps 212 and 214. At the same time, the TF information is transmitted to the base station.

That is, in step 212, the terminal transmits the TF information to the base station. The TF information includes an Enhanced Transport Format Combination Indicator (hereinafter referred to as "E-TFCI") indicating information of a resource necessary for demodulating E-DCH data. In addition, in step 214, the UE selects a modulation and coding scheme (MCS) level in consideration of the state of a channel allocated from the base station, modulates and encodes uplink data according to the MCS level, and then moves to the base station. send. For reference, a physical layer channel for transmitting the E-TFCI information is called an E-DCH Dedicated Physical Control Channel (E-DPCCH), and a physical layer channel for transmitting the uplink packet data is an E-DCH Dedicated. Physical Data Channel). A dedicated physical control channel (DPCCH) is transmitted together with the E-DPDCH / E-DPCCH. The DPCCH is used for channel estimation and power control of a base station.

In step 216, the base station determines whether there is an error in the TF information and the packet data. In step 218, the base station transmits NACK (Negative Acknowledge) if an error occurs in any one of the error determination results, and ACK (Acknowledge, Acknowledgment information) if all errors are not found in the E-HICH (E-DCH HARQ Indicator). Channel) to the terminal. When the ACK information is transmitted, the packet data is completed and the terminal transmits new user data through the E-DCH. However, when the NACK information is transmitted, the terminal retransmits the packet data having the same contents through the E-DCH.

In the above environment, if the base station can receive scheduling information such as the buffer state and the power state of the terminal from the terminal, the base station can be provided to a terminal far away or a terminal with poor channel conditions, or a terminal with low priority for data to be serviced. It is possible to allocate a high data rate to a terminal having a low data rate, a terminal in close proximity or a good channel condition or a high priority of data to be serviced, thereby improving the performance of the entire system.

5. RACH

(1) RACH concept

Hereinafter, a physical layer transmission procedure of a random access channel (hereinafter referred to as "RACH") will be described. RACH is a type of uplink transmission channel used for the UE to signal to the base station. In more detail, the RACH is used to register a terminal in a network, update location information of the terminal, call initiation, and the like after the terminal is powered on. Therefore, the RACH has a characteristic that the data rate is relatively low and the cell coverage is high.

(2) base station approach of RACH

The "random access" is derived from the manner in which the terminal accesses the base station. That is, a method in which the terminal attempts to connect to the base station at a predetermined power initially, and if the connection is not established, increases the power a little again and reconnects the random access method.

In more detail, since the RACH is transmitted without a call connection of the UE, the UE cannot exactly know the transmission power value required for the UE. Therefore, through the open-loop power control (open-loop power control) roughly adjust the transmit power value required for the RACH transmission.

(3) physical layer transmission procedure of RACH

Hereinafter, the data transmission procedure between the terminal and the base station in the RACH physical layer will be described in detail.

The RACH consists of a "RACH preamble" (hereinafter referred to as "preamble") and a "RACH message" for data transmission. The preamble is used by the terminal to make an initial connection to the base station, and the RACH message is used to transmit data to the base station by the terminal after the connection. In addition, the base station operates an Acquisition Indicator Channel (AICH) as a response channel for the preamble.

First, the UE finds a resource for RACH transmission through a broadcast channel (BCH). The RACH transmission resource includes RACH access slots (RACH access slots) indicating a RACH transmission interval, signature information for identifying each UE, and the like. The UE arbitrarily selects a predetermined RACH access slot and predetermined signature information from the RACH transmission resource. In addition, the initial transmission power of the terminal is determined by measuring the downlink channel received by the terminal to reflect a predetermined offset (offset). Thereafter, the UE transmits the preamble including the selected signature information in the selected RACH access slot at the determined initial transmit power.

If the base station receives the preamble transmitted by the terminal without error, the base station feeds back the signature information included in the received preamble to the terminal through the AICH. The AICH functions as an acknowledgment for the received preamble. Therefore, the terminal receiving the AICH from the base station is connected to the base station and thus transmits a RACH message to the base station. If the base station fails to receive the preamble, the base station does not feed back the AICH to the terminal. Therefore, since the terminal has not received the ACK for the preamble, it will have to retransmit the preamble. The transmit power applied to this preamble retransmission is higher than the initial transmit power by a predetermined value. If the base station does not receive the retransmitted preamble, the preamble is transmitted again, and the transmission power is higher by a predetermined value than the previous transmission power. Through this process, the base station receives the preamble without error. An example of the above-described process will be described below with reference to FIG. 3.

3 is an exemplary diagram of a RACH physical layer transmission procedure.

Reference numeral 312 denotes a preamble (hereinafter, abbreviated to "initial preamble") that the terminal first transmits to the base station. It was assumed that the initial preamble was transmitted at t1 304 but the base station did not receive it. Therefore, since the base station cannot transmit the AICH to the terminal, the terminal retransmits the preamble. Reference numeral 314 denotes a "retransmission preamble" transmitted by the terminal at time t2 306. In this case, it is as described above that the transmission power becomes higher than the previous transmission power. It is assumed that the base station has received the retransmission preamble, and the base station notifies the terminal that the preamble has been received by feeding back the AICH 316 to the terminal at t3. The terminal receiving the AICH 316 transmits the RACH message 318 at t4.

For reference, t _pp 320, t _pa 322, and t _pm 324 shown in FIG. 3 are predetermined values, which are known to both the terminal and the base station. T _pp 320 is the time interval between the transmitted preambles, t _pa 322 is the time interval between the preamble and the AICH for it, and t _pm 324 is the time between the RACH message and the previous preamble. It means the time interval.

(4) Enhanced RACH

The E-DCH and RACH have been described so far. Recently, in order to improve the performance of the RACH, the introduction of the E-DCH in the RACH has been actively discussed. This is to support a service requiring periodic data connection such as an HTTP request or a service that requires a relatively higher data rate than a conventional RACH or a Voice over Internet Protocol (VoIP) service.

That is, the E-DCH or HSUPA (High Speed Uplink Packet Access) transmission method is introduced into the existing RACH transmission procedure to improve the performance of the existing RACH. Hereinafter, for convenience of description, an RACH having improved performance will be referred to as an enhanced RACH (E-RACH). Accordingly, it is necessary to define a specific transmission procedure for supporting the E-RACH.

In accordance with the above-described needs, the present invention provides a base station apparatus and method for controlling interference occurring in one cell in a mobile communication system using an enhanced random access channel.

In addition, the present invention provides an apparatus and method of a terminal for transmitting and receiving data to reduce interference generated in one cell in a mobile communication system using an enhanced random access channel.

Accordingly, in a mobile communication system using an enhanced random access channel (E-RACH) provided by the present invention, a method for transmitting and receiving data of a base station includes: checking whether a preamble transmitted by the terminal is received without error; When the preamble is received without error, generating an ACK corresponding to the preamble by using the information included in the received preamble and transmitting the ACK to the mobile station; and receiving the power control preamble transmitted by the mobile station receiving the ACK. And receiving and performing power control on the terminal using the power control preamble, and receiving data transmitted by the terminal according to the power control.

When the effect obtained by the typical thing of the invention disclosed by this invention is demonstrated briefly, it is as follows. The present invention defines an E-AGCH transmission format and related E-RACH transmission procedure for improving the E-RACH transmission procedure in a mobile communication system using an enhanced random access channel. To effectively control the

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention to be described below will be described with reference to an example of transmitting data using an E-DCH when transmitting data to which the E-RACH transmission procedure is applied in a UMTS communication system.

1. E-RACH Transfer Procedure

(1) E-RACH configuration and transmission procedure

The E-RACH consists of an "E-RACH preamble" ("preamble"), a "power control preamble", and an "E-RACH message". The preamble is used for initial access by the terminal to the base station, and the power control preamble functions to adjust the transmission power when transmitting the E-RACH message. The E-RACH message is used to transmit actual data to the base station by the terminal after the power control. In the present invention, the E-RACH message will follow the E-DCH transmission scheme. In addition, the base station operates an Enhanced-Acquisition Indicator Channel (E-AICH) as a response channel for the preamble.

The general E-RACH transmission procedure will now be described with reference to FIG.

4 is a conceptual diagram illustrating an E-RACH transmission procedure according to an embodiment of the present invention.

FIG. 4 illustrates a process from when two terminals 402 and 404 transmit an E-RACH using the same resource to generate a contention and then to contention resolution. Prior to transmitting the E-RACH, the UE finds the E-RACH transmission resource through the broadcast channel. The E-RACH transmission resource includes E-RACH access slots (RACH access slots) indicating a transmittable interval, E-RACH signature information for identifying a terminal, and uplink scrambling for E-RACH transmission. It includes information such as a code set, Enhanced Relative Grant Channel (E-RGCH) / Enhanced Access Grant Channel (E-AGCH) code information set, timing offset information, and the like.

The terminal arbitrarily selects a predetermined E-RACH access slot and predetermined E-RACH signature information among the E-RACH transmission resources. In addition, the initial transmission power of the terminal is determined by measuring the downlink channel received by the terminal to reflect a predetermined offset. Thereafter, the terminal transmits a preamble including the selected signature information in the selected RACH access slot at the determined initial transmit power.

(2) preamble transmission

In FIG. 4, the terminal # 1 402 transmits the initial preamble 422 to the base station at the initial transmission power at the time t1 406. In addition, the terminal # 2 404 also transmits the initial preamble 442 including the same signature information as the terminal # 1 at the time t1 406 at the initial transmission power. Accordingly, a contention occurs between both terminals.

The initial preambles 422 and 442 transmitted by the terminal # 1 402 and the terminal # 2 404 are not transmitted to the base station 400, and the E-AICH, which is a response signal to the initial preamble from the base station 400, is transmitted. (Enhanced Acquisition Indicator Channel) could not be received within a predetermined time.

Accordingly, the terminal # 1 402 and the terminal # 2 404 increase the transmission power by a predetermined value than the initial transmission power to transmit the retransmission preambles 424 and 444 at t2 through the available access slots. The retransmission preambles 424 and 444 continue to generate contention, including the same signature information.

The base station 400 receives the retransmission preambles 424 and 444 without error and transmits the E-AICH 426 to the terminals 402 and 404 at the time t3 410. The E-AICH includes signature control information or signature information included in the preamble received by the base station and predefined control information having a one-to-one correspondence with the information and transmission resource information of data to be transmitted by the terminal. For example, transmission resource information of data to be transmitted by the terminal may be specific control information among E-RACH related control information sets notified to the terminal through a broadcast channel.

Upon receipt of the E-AICH 426 from the base station, the terminals 402 and 404 determine that the signature information or the predefined control information included in the E-AICH is the same as the signature information of the preamble transmitted by the base station. Resource information for data transmission is obtained from transmission resource information of the AICH.

(3) power control preamble transmission

The terminal transmits a power control preamble to the base station for a predetermined Npcp time interval before the actual data transmission. The power control preamble functions to adjust a transmission power value during actual data transmission. That is, by performing the power control during the Npcp time interval, it is to determine the appropriate transmission power value in the actual data transmission. In FIG. 4, it is assumed that the Npcp 458 time period is set to t4 412 to t5 414.

(4) E-RACH message (data) transmission

The terminal starts data transmission from the time t5 414 after the power control preamble transmission is terminated. The transmission of the data follows the E-DCH transmission scheme. The transmission resource of the first transmitted data follows the transmission resource information notified by the E-AICH, and the scheduling command for the first transmitted data is a broadcast channel or an appointment in advance. Apply the defined values.

The data is transmitted through the physical channel E-DPDCH, which includes a UE-specific identification (UE-ID) in the E-DPDCH so that the base station can use it for contention resolution. That is, even if a plurality of terminals transmit data using the same transmission resource, the base station can distinguish from which UE the data from the UE-ID. In addition, when transmitting the E-DPDCH, the UE also transmits the E-DPCCH including information on the transmission format of the E-DPDCH and the DPCCH used for channel estimation and power control to the base station.

(5) Specific example of data transmission

At time t5 (414), the terminal # 1 402 transmits its own UE-ID # 1 402 and data to be transmitted (432), and the terminal # 2 transmits data to be transmitted with its UE-ID # 2. (450). Each terminal may continue to transmit data until the collision is resolved (436, 452).

The base station 400, which received the initial transmission data of the terminal without error, feeds back the E-AGCH to the corresponding terminal in response. The E-AGCH includes the UE-ID of the terminal for data received without error.

4 illustrates a situation in which the base station receives the data transmitted by the terminal # 1 402 without an error in a collision state and includes the UE-ID # 1 in the E-AGCH to the terminal at the time t6 416. The terminal # 1 402 succeeds in detecting its UE-ID # 1 at t7 418, which is the reception point of the E-AGCH, and thus can continuously transmit the data (438, 440). However, UE # 2 fails to detect its UE-ID # 2 at t7 418, which is the reception point of the E-AGCH.

On the other hand, each terminal operates a predetermined timer to further ensure the UE-ID detection time. That is, the base station presets the time of the timer in consideration of the case where the terminal does not initially receive the data initially transmitted, but receives the data after several retransmissions. Time setting of the timer may be possible using a broadcast channel or a preset method.

The time of the timer is set to a time interval of T_contention (t5 to t8) 460 from the end of the power control preamble. At this time, the start time of the T_contention 460 may be set equal to the start time t4 of the power control preamble including the Npcp time interval.

If the UE fails to detect its UE-ID until the timer set in this manner ends, the UE determines that a collision has occurred, stops further data transmission, and performs the E-RACH transmission procedure again from the beginning.

Therefore, in FIG. 4, the terminal # 2 404 causes uplink interference during the time period of t4 to t8 462. In particular, since the terminal # 2 404 continues to cause uplink interference even after t7 418, which is the E-AGCH reception time of the terminal # 1 402, the system performance is adversely affected. Although FIG. 4 assumes a collision between two terminals, it is of course possible to expand the collision between N terminals.

2. Basic concept of invention

Accordingly, the present invention proposes a method for minimizing interference caused by the UE # 2 404 of FIG. 4.

When the terminal transmits the first data, the terminal transmits its own unique ID to the base station, and the base station generates the E-AGCH corresponding to the initial data and transmits the same to the terminal. At this time, the unique ID of the terminal is included and transmitted to the terminal. When the UE receives the E-AGCH, it checks whether the unique ID matches its ID. If it matches, it keeps sending data and if it doesn't, it stops sending data.

3. Transmission format of E-AGCH

5 is a configuration diagram of a transmission format of an E-AGCH according to an embodiment of the present invention. The E-AGCH includes a UE-specific UE-ID 502 and a common ID 504 between the E-RACH terminals. That is, the base station configures UE-ID unique to the UE as control information of the E-AGCH for data received without error from the UE.

When the maximum size of the control information 506 that can be transmitted in the E-AGCH is M bits, in order to transmit 16 bits of the unique UE-ID 502 of the general terminal, the upper M bits of the UE-specific UE-ID are used as the control information. send. In general, since the maximum size of the control information 506 that can be transmitted through the E-AGCH is 6 bits, the upper 6 bits of the 16-bit UE-specific UE-ID 502 are transmitted as the control information.

Examples of the unique UE-ID of the UE include an E-DCH Radio Network Temporary Identifier (E-RNTI) or a Cell Radio Network Temporary Identifier (C-RNTI). The base station generates a CRC composed of 16 bits from the control information configured from the UE-specific UE-ID, masks (or XORs) the generated CRC with the common ID 504, and concatenates the control information (510). After the channel coding is transmitted to the terminal.

The UE receives the E-AGCH from the base station, performs reverse masking (or XOR) with the common ID on the received E-AGCH, decodes the reverse masked E-AGCH, and the decoding result passes the CRC check. If it matches the UE's unique UE-ID, it is determined that data transmission can continue. As a result of the determination, the terminal may continuously transmit data if necessary.

If the decoding result of the demasked E-AGCH does not have a CRC check error, but does not match its own UE-ID, the UE determines that a contention has occurred and stops data transmission. For reference, the case of "no CRC check error, but does not match its own UE-ID" corresponds to a case where the common ID is correctly applied but the UE-specific UE-ID is different.

If a decoding result of the demasked E-AGCH results in a CRC check error, the UE retries receiving the E-AGCH until the timer expires. For reference, the " CRC check error " corresponds to a case of reverse masking with an incorrect common ID or failing to overcome the error of the E-AGCH by decoding due to a poor channel condition.

4. E-RACH transmission procedure applying the E-AGCH transmission format

6 is a conceptual diagram illustrating an E-RACH transmission procedure to which an E-AGCH transmission format is applied according to an embodiment of the present invention.

FIG. 6 illustrates a process from two terminals 602 and 604 to transmit an E-RACH using the same resource, and then to contention resolution after a collision occurs.

(1) Resource recognition for E-RACH transmission

Prior to transmitting the E-RACH, the UE finds the E-RACH transmission resource through the broadcast channel. The E-RACH transmission resource includes E-RACH access slots indicating an E-RACH transmission interval, E-RACH signature information for terminal identification, uplink scrambling code set for E-RACH transmission, and E-RACH terminals. Information such as a common ID set, an E-RGCH / E-AGCH code information set, timing offset information, and the like shared between them.

The terminal arbitrarily selects a predetermined E-RACH access slot and predetermined E-RACH signature information among the E-RACH transmission resources. In addition, the initial transmission power of the terminal is determined by measuring the downlink channel received by the terminal to reflect a predetermined offset. Thereafter, the UE transmits the preamble including the selected signature information in the selected RACH access slot at the determined initial transmit power.

(2) preamble transmission

In FIG. 4, the terminal # 1 402 transmits the initial preamble 422 to the base station at the initial transmission power at the time t1 406. In addition, the terminal # 2 404 also transmits the initial preamble 442 including the same signature information as the terminal # 1 at the time t1 406 at the initial transmission power.

In FIG. 6, the initial preamble 622 of the terminal # 1 602 is transmitted to the base station at the initial transmission power at the time t1 606. In addition, the terminal # 2 604 also transmits the initial preamble 642 including the same signature information as the terminal # 1 at the time t1 (606) to the initial transmission power. Accordingly, a contention occurs between both terminals.

The initial preambles 422 and 442 transmitted by the terminal # 1 602 and the terminal # 2 604 could not be transmitted to the base station 600, and the E-AICH, which is a response signal to the initial preamble from the base station 600, is transmitted. (Enhanced Acquisition Indicator Channel) could not be received within a predetermined time.

Accordingly, the terminal # 1 602 and the terminal # 2 604 increase the transmission power by a predetermined value from the initial transmission power to transmit the retransmission preambles 624 and 644 at t2 through the available access slots. Since the retransmission preambles 624 and 644 contain the same signature information, contention continues to occur.

The base station 600 receives the retransmission preambles 624 and 644 without error and transmits the E-AICH 626 to the terminals 602 and 604 at the time t3 610.

The E-AICH is one-to-one correspondence with the signature information included in the preamble received by the base station or predefined control information having a one-to-one correspondence with the signature information, transmission resource information of the data to be transmitted by the terminal, and the transmission resource information. Contains a common ID in. For example, the transmission resource information of the data to be transmitted by the terminal may be specific control information among E-RACH related control information sets notified to the terminal through a broadcast channel.

Upon receiving the E-AICH 626 from the base station, the terminals 602 and 604 may use the signature information included in the E-AICH or the signature information of the preamble transmitted by the predefined control information having a one-to-one correspondence with the signature information. It determines that it is the same as, and obtains the resource information for data transmission from the E-AICH transmission resource information.

(3) power control preamble transmission

The terminal transmits a power control preamble to the base station for a predetermined Npcp time interval before the actual data transmission. The power control preamble functions to adjust a transmission power value during actual data transmission. That is, by performing the power control during the Npcp time interval, it is to determine the appropriate transmission power value in the actual data transmission. In FIG. 6, it is assumed that the Npcp 658 time interval is set to t4 612 to t5 614.

(4) data transmission

The terminal starts data transmission from the time t5 414 after the power control preamble transmission is terminated. The transmission of the data follows the E-DCH transmission scheme. The transmission resource of the first transmitted data follows the transmission resource information notified by the E-AICH, and the scheduling command for the first transmitted data is a broadcast channel or an appointment in advance. Apply the defined values.

The data is transmitted through the physical channel E-DPDCH, which includes a UE-specific identification (UE-ID) in the E-DPDCH so that the base station can use it for contention resolution. That is, even if a plurality of terminals transmit data using the same transmission resource, the base station can distinguish from which UE the data from the UE-ID. In addition, when the UE transmits the E-DPDCH, the E-DPCCH including information on the transmission format of the E-DPDCH and the DPCCH used for channel estimation and power control are also transmitted to the base station.

(5) Specific example of data transmission

At time t5 614, the terminal # 1 602 transmits its UE-ID # 1 602 and data to be transmitted (632), and the terminal # 2 transmits data to be transmitted with its UE-ID # 2. (650). Each terminal may continue to transmit data until the collision is resolved (636, 652).

The base station 600, which received the initial transmission data of the terminal without error, feeds back the E-AGCH to the corresponding terminal in response. The E-AGCH is configured with control information from the UE-ID of the corresponding terminal for data received without error. At this time, the base station 600 additionally transmits a common ID to the terminal.

6 shows that the base station receives the data transmitted by the terminal # 1 602 without error and configures control information from the UE-ID # 1 in a collision state, and at the time t6 616, a common ID is additionally transmitted to the terminal. Indicates a situation.

The terminal # 1 602 reverse masks the E-AGCH using the common ID obtained when the E-AICH is received at t7 618, which is the reception point of the E-AGCH, and reverse masks the E-AGCH. It is assumed that the control information of M bits obtained by decoding is matched with the upper M bits of its UE-ID # 1. Therefore, the terminal # 1 602 may continue to transmit data (638, 640).

However, UE # 2 604 reversely masks the E-AGCH without error at t7 618, which is the reception point of the E-AGCH, by using the common ID obtained when the E-AICH is received. It is assumed that the control information of M bits obtained by decoding one E-AGCH does not match the upper M bits of its UE-ID # 2. Accordingly, the terminal # 2 604 knows that a collision has occurred.

On the other hand, each terminal operates a predetermined timer to further ensure the UE-ID detection time. That is, the base station presets the time of the timer in consideration of the case where the terminal does not initially receive the data initially transmitted, but receives the data after several retransmissions. Time setting of the timer may be possible using a broadcast channel or a preset method.

The time of the timer is set to a time interval of T_contention (t5 to t8) from the end of the power control preamble. At this time, the start time of the T_contention 660 may be set equal to the start time t4 of the power control preamble including the Npcp time interval.

If the UE fails to detect its UE-ID until the timer set in this manner ends, the UE determines that a collision has occurred, stops further data transmission, and performs the E-RACH transmission procedure again from the beginning.

Accordingly, in the case of FIG. 6, the terminal # 2 604 causes uplink interference during the time period of t4 to t8 662. That is, unlike the case of FIG. 4 described above, it is possible to determine whether a collision occurs at the time t7 (618), which is the point of E-AGCH reception, so that after the time t7, no further uplink interference can be obtained from the terminal # 2 (604). It can improve system efficiency by not causing it. Although FIG. 6 assumes a case where a collision occurs between two terminals, it can be expanded even when a collision occurs between N terminals.

5. Transmission and reception method in base station

Hereinafter, a method of transmitting and receiving at a base station according to an E-RACH transmission procedure proposed by the present invention will be described.

7 is a flowchart illustrating a transmission / reception method at a base station according to an E-RACH transmission procedure according to an embodiment of the present invention.

In step 702, the base station detects a preamble from the terminal, and determines whether or not the preamble detected in step 704 without an error (acquisition). When the terminal transmits the preamble, the base station may inform the terminal in advance through a broadcast channel. In this way, the transmission and reception timing of the preamble available between the terminal and the base station can be known in common. If the base station acquires the preamble without error, the process proceeds to step 706. If the base station does not acquire the preamble, the process returns to step 702 to detect the preamble again. In this case, the redetection time point of the preamble can be known by setting the transmission time point of the preamble and the transmission time point of the retransmission preamble previously transmitted by the UE in advance.

In step 706, the base station generates and transmits an E-AICH corresponding to the received preamble. The E-AICH is one-to-one correspondence with signature information included in the preamble received by the base station or predefined control information having a one-to-one correspondence with the signature information, transmission resource information of the data to be transmitted by the terminal, and the transmission resource information. Contains a common ID in. The control information can have a one-to-one correspondence at this time, thereby reducing the amount of information required. In addition, the time interval between the received preamble and the E-AICH may be defined as a predetermined value.

In step 708, the base station receives the power control preamble from the terminal and performs power control for the terminal. The reception time and the transmission section of the power control preamble are preset to a predetermined value so that both the terminal and the base station can know the same. In step 710, the base station receives data transmitted by the terminal after receiving the power control preamble. If the data is received without error, the flow proceeds to step 712.

In step 712, the base station configures the E-AGCH control information from the UE-ID of the terminal that has received the received data, adds a common ID together, generates an E-AGCH, and transmits it to the terminal. If an error occurs in the initial data received from the terminal, the base station instructs the terminal to retransmit the data that failed to be received, and accordingly receives the retransmitted data and then decodes the original data received by combining with the previously received data. do.

6. Transmission and reception method in the terminal

Hereinafter, a method of transmitting and receiving at a terminal according to an E-RACH transmission procedure proposed by the present invention will be described.

8 is a flowchart illustrating a transmission and reception method in a terminal according to an E-RACH transmission procedure according to an embodiment of the present invention.

In step 802, the UE detects a broadcast channel before starting the E-RACH transmission and finds a resource for the E-RACH transmission. The E-RACH transmission resource may include E-RACH access slots indicating an E-RACH transmission interval, signature information for terminal identification, uplink scrambling code set for E-RACH transmission, and an E-RACH terminal. Information such as a common ID set, an E-RGCH / E-AGCH code information set, timing offset information, and the like shared between them.

In operation 804, a predetermined E-RACH access slot and predetermined signature information are arbitrarily selected among the information found through the broadcast channel detection, and a preamble including the selected signature information is transmitted in the selected E-RACH access slot. . In this case, the transmission power of the preamble is determined by measuring a downlink channel received by the terminal to reflect a predetermined offset.

In step 806, after a predetermined time from the preamble transmission time of step 804, the base station corresponding to the preamble attempts to detect the E-AICH transmitted. If the detection of the E-AICH corresponding to the recently transmitted preamble is successful in step 808, the process proceeds to step 810 to generate E-RACH data. If the detection of the E-AICH fails, the flow returns to step 804 to retransmit the preamble.

The E-AICH transmitted by the base station includes signature information used by the corresponding UE in the most recent preamble transmission or predefined control information in a one-to-one correspondence with the signature information. Therefore, when the UE acquires its signature information when detecting the E-AICH, it can determine that the ACK is obtained from the base station.

As described above, the transmission time interval of the preamble recently transmitted by the UE and the transmission time interval of the E-AICH transmitted by the BS are defined as preset values. In addition, when the terminal retransmits the preamble, the transmission power is increased by a predetermined value higher than the transmission power of the preamble transmitted by the terminal and transmitted through the available E-RACH access slot as described above. In this way, the retransmission time of the preamble is defined as a predetermined value based on the transmission time of the preamble most recently transmitted by the terminal, so that both the terminal and the base station can know the transmission and reception time of the available preamble.

In step 808, the UE determines whether an ACK has been obtained from the E-AICH, and if so, proceeds to step 810, and if not, returns to step 804. In step 810, the UE transmits the power control preamble for a predetermined time interval. After the transmission time interval of the power control preamble ends, the terminal transmits the first data of the E-RACH through the E-DPDCH at 812. At this time, the E-DPCCH including information on the transmission format of the E-DPDCH and the DPCCH for channel estimation and power control are also transmitted. The initial data of the E-RACH transmitted by the UE includes UE-specific UE-ID, and a transmission time is defined as a preset value based on the transmission time of the preamble most recently transmitted by the UE. In this way, both the terminal and the base station can know the time of transmission and reception of the E-RACH data.

In step 814, the UE receives the E-AGCH, reverse masks the E-AGCH using a common ID, and then decodes the reverse masked E-AGCH.

In step 816, the CRC error check is performed on the control information of the decoded M bits of the E-AGCH. If there is an error as a result of the CRC error check, the process proceeds to step 814 and retries E-AGCH reception until the timer expires.

In step 818, it is checked whether control information of M bits without its CRC error matches the upper M bits of the UE-specific UE-ID. If there is a match, the UE has obtained a unique UE-ID, so the process proceeds to step 820 and continuously transmits the data in the next order. Restarts the E-RACH transfer procedure.

7. Transceiver of base station

9 is a block diagram of a transmission and reception apparatus at a base station according to an E-RACH transmission procedure according to an embodiment of the present invention. The receiving unit 902 performs a predetermined signal processing on the signal received from the terminal by the base station and outputs it. The output signal of the receiver is input to the preamble detector 906. The preamble detector 906 checks whether the received signal has been received without error. If the preamble is received without error, the preamble detector 906 outputs the signature information of the terminal to the E-AICH generator 910. The E-AICH generator 910 has a common one in one-to-one correspondence with signature information of the terminal or predefined control information having a one-to-one correspondence with the signature information, transmission resource information of the data to be transmitted by the terminal, and the transmission resource information. An ACK (acknowledgement or acquisition) including an ID is generated to configure an E-AICH.

The E-AICH is output to the transmitter 904 and transmitted to the terminal after a predetermined signal processing by the transmitter 904. If the base station fails to detect the preamble, the base station waits for reception of the next retransmission preamble. The transmission time interval between the preambles in the terminal is defined as a preset value.

 The preamble detector 906 outputs information on whether the preamble has been received without error to the E-RACH controller 918 to allow the base station to control whether the E-AICH is generated and the E-AICH transmission time or retransmit from the terminal. The reception timing of the preamble is controlled. The base station receives the power control preamble from the terminal through a power control preamble / E-DPDCH / E-DPCCH / DPCCH detector 912 after a predetermined time after the E-AICH transmission for a predetermined time period to perform power control for the terminal. To perform. After receiving the power control preamble, the E-DPDCH / E-DPCCH / DPCCH is received and decoded. The E-AGCH generator 916 configures E-AGCH control information from the UE-ID unique to the decoding result, generates a CRC from the E-AGCH control information, and then masks the common ID and the CRC. -Channel coding with AGCH control information. The channel-coded E-AGCH signal is transmitted to the terminal through a predetermined signal processing in the transmitter 904. The power control preamble / E-DPDCH / E-DPCCH / DPCCH detector 912 notifies the E-RACH controller 918 of the reception time of the power control preamble / E-DPDCH / E-DPCCH / DPCCH, and the E-RACH The controller 918 allows the E-AGCH generator 916 to control whether and when the E-AGCH is generated.

8. Transceiver of terminal

10 is a block diagram of a transmitting and receiving apparatus of a terminal performing an E-RACH transmission procedure according to an embodiment of the present invention.

The broadcast channel detector 1006 detects a broadcast channel and finds a resource for E-RACH transmission. The E-RACH transmission resource includes E-RACH access slots indicating an E-RACH transmission interval, signature information for terminal identification, uplink scrambling code set for E-RACH transmission, and E-RACH terminals. Information such as a common ID set, an E-RGCH / E-AGCH code information set, timing offset information, and the like shared between them.

The broadcast channel detector 1006 outputs the E-RACH transmission resource obtained from the base station to the E-RACH controller 1018. The E-RACH controller 1018 controls the preamble, E-AGCH, and data transmission of the terminal.

When there is E-RACH data to be transmitted, the preamble generator 1014 receives the E-RACH access slot and E-RACH signature information from the E-RACH controller 1018, generates a preamble, and generates a preamble through the base station through the transmitter 1004. To transmit. The preamble generator 1014 controls the preamble transmission time by the control of the E-RACH controller 1018.

If a predetermined time passes after the preamble transmission time, the UE attempts to detect the E-AICH corresponding to the preamble under the control of the E-RACH controller 1018. That is, the signal received from the base station passes through a predetermined signal processing process through the receiver 1002, and then is input to the E-AICH detector 1008, which is most recently transmitted by the UE in the E-AICH detector 1008. It is determined whether the E-AICH is detected by checking whether the signature information included in the preamble is included in the received signal.

If the E-AICH detection fails, the E-RACH controller 1018 controls the preamble generator 1014 to retransmit the preamble. In addition to the E-RACH signature information, the E-AICH includes transmission resource information of data to be transmitted by the terminal, and information on a common ID having a one-to-one correspondence with the transmission resource information.

If the UE succeeds in detecting the E-AICH, the power control preamble / E-DPDCH / E-DPCCH / DPCCH generator 1012 generates and transmits the power control preamble for a predetermined time period, and then transmits the E-RACH data to the E-RACH data. It is configured as a DPDCH and transmitted to the base station through the transmitter 1004. At this time, the E-DPCCH including information on the transmission format of the E-DPDCH and the DPCCH for channel estimation and power control are also configured and transmitted.

 When the UE transmits the E-RACH data, the UE inserts and transmits its own UE-ID. The power control preamble / E-DPDCH / E-DPCCH / DPCCH generator 1012 adjusts the transmission time and transmission format of the power control preamble or E-RACH data by the control of the E-RACH controller 1018. In addition, when the power control preamble / E-DPDCH / E-DPCCH / DPCCH generator 1012 is notified of the success of the E-AICH detection from the E-AICH detector 1008, when the E-AICH is successfully received. Transmit power control preamble and E-RACH data only.

The terminal attempts to detect the E-AGCH through the E-AGCH detector 1010 after a predetermined time has passed since the transmission of the E-RACH data by the control of the E-RACH controller 1018.

The terminal reverse masks the received E-AGCH using a common ID, and then decodes the reverse masked E-AGCH. If the control information of the decoded M bits of the E-AGCH passes the CRC check and matches the upper M bits of its own UE-ID, the UE continues to transmit the next data.

If the decoding result does not have a CRC check error, but does not match its own UE-ID, the UE determines that a collision has occurred, and further stops data transmission and starts the E-RACH transmission procedure again.

If the decoding result fails the CRC check, the UE retries the reception of the E-AGCH until the timer expires. The E-AGCH detector 1010 applies the successful detection of the E-AGCH to the E-RACH controller 1018 to allow the E-RACH controller 1018 to control subsequent procedures according to whether the E-AGCH is detected.

1 is a conceptual diagram illustrating uplink packet transmission through an E-DCH in a general wireless communication system;

2 is a flowchart illustrating a transmission and reception procedure through a typical E-DCH;

3 is an exemplary diagram of a RACH physical layer transmission procedure;

4 is a conceptual diagram illustrating an E-RACH transmission procedure according to an embodiment of the present invention;

5 is a configuration diagram of a transmission format of an E-AGCH according to an embodiment of the present invention;

6 is a conceptual diagram illustrating an E-RACH transmission procedure to which an E-AGCH transmission format is applied according to an embodiment of the present invention;

7 is a flowchart illustrating a transmission and reception method at a base station according to an E-RACH transmission procedure according to an embodiment of the present invention;

8 is a flowchart illustrating a transmission and reception method in a terminal according to an E-RACH transmission procedure according to an embodiment of the present invention;

9 is a block diagram of a transmission and reception apparatus at a base station according to an E-RACH transmission procedure according to an embodiment of the present invention;

10 is a block diagram of a transmitting and receiving device of a terminal performing an E-RACH transmission procedure according to an embodiment of the present invention.

Claims (1)

In the mobile communication system for transmitting and receiving data between the base station and the terminal through an enhanced random access channel (E-RACH), Checking whether the preamble transmitted by the terminal has been received without error; When the preamble is received without error, generating an ACK corresponding to the preamble by using information included in the received preamble and transmitting the ACK to the terminal; Receiving a power control preamble transmitted by the terminal receiving the ACK and performing power control on the terminal using the power control preamble; And receiving data transmitted from the terminal according to the power control.

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