KR20150017488A - Method and Apparatus for decision to transmission power of Random Access Preamble - Google Patents

Abstract

The present invention relates to a method and apparatus for determining the transmission power of a random access preamble for a random access procedure of a handover process in a wireless communication system. The method for determining the transmission power of the random access preamble according to one embodiment of the present invention includes the steps of: receiving a handover request from a user terminal which receives a wireless communication service; setting information about the transmission power of the random access preamble according to quality of service class identifier (QCI) of the wireless communication service; and transmitting the information about the determined transmission power to the user terminal. The QCI has each preset priority. The transmission power is determined according to the QCI with the highest priority among the QCIs of the wireless communication service.

Description

[0001] The present invention relates to a method and apparatus for determining a transmission power of a random access preamble (Random Access Preamble)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a random access procedure during a handover procedure in a wireless communication system, and more particularly, to a random access procedure And a device therefor.

2. Description of the Related Art [0002] In recent wireless communication systems, various types of communication services including voice, data, and the like are widely provided to a terminal user through one base station or a base station. Generally, one base station includes one or more cells And one cell may be divided into a plurality of sectors.

Unlike a wired communication system, a wireless communication system provides the above communication service to terminals having mobility. In this case, a terminal user may move between sectors or between cells in the course of receiving a communication service.

In this case, in order for the wireless communication system to provide a seamless service to the user equipment (UE), the base station providing the communication service to the terminal or the frequency band used by the terminal needs to be changed accordingly.

That is, when a mobile station moves from a serviceable area of a specific base station to a serviceable area of another base station in a state where a call is connected to a specific base station and a service is provided, a service is provided to the user terminal and the user terminal The connection between the serving base station and the serving base station must be transferred to a neighboring base station before continuous service can be provided. In this case, a procedure for transferring the connection between the mobile station and the base station is required. ).

In a handover procedure, a base station that is connected to a terminal and provides a current service is referred to as a source base station, and a neighbor base station to be newly connected is referred to as a target base station.

Meanwhile, in order to perform the handover procedure, the UE attempts initial access to the target BS. Such initial access may be performed through a random access channel (RACH).

The terminal accesses the base station through the random access channel (RACH) when the off-state power is turned on or when the base station is turned on for a long period of time after being in the idle state for a long time, And can communicate with each other.

However, since the random access channel (RACH) is a channel commonly used by a plurality of terminals, when a plurality of terminals attempt to transmit signals to the base station through a random access channel (RACH) at the same time, have.

Therefore, in order to prevent such a collision between signals, a UE transmits a random access preamble to a base station before a random access channel (RACH) message is transmitted to secure a communication channel.

In this case, in order to increase the probability that a base station receives a random access preamble from a user terminal, it is desirable that the transmission power when a user terminal transmits a random access preamble is increased as much as possible.

However, when the transmission power of the Random Access Preamble is unnecessarily high, it may cause interference to the adjacent base station and may consume more power than necessary for transmission of a Random Access Preamble A problem can arise.

Accordingly, after transmitting a random access preamble with a predetermined initial transmission power, the UE transmits a random access preamble with a predetermined size until the base station can completely receive the random access preamble. A random access preamble (Random Access Preamble) is transmitted while increasing the transmission power compared to the previous transmission power by ranping the transmission power magnitude.

In general, handover can be classified into softer handover, soft handover and hard handover.

To be more specific, a softer handover is a handover in a cell, and a handover method in which a UE switches from a current channel to a good channel among channels being used in a cell coverage (Cell Coverage) .

In addition, when soft handover is desired to switch from one channel to another, it tries to connect to another channel while maintaining connection with one channel, and eventually connects to one channel Is a handover method for disconnecting a mobile station.

Hard handover refers to a handover method in which, in a case of switching from one channel to another, unlike soft handover, a connection with one channel is disconnected and a connection with another channel is immediately established.

On the other hand, an LTE (Long Term Evolution) system that provides real-time services such as communication services and data services, such as Conversational Service, supports only the hard handover method among the above handover methods.

Accordingly, in the LTE system, a handover is performed through a connection with another channel after a terminal disconnects a channel with which the terminal is currently connected. After the connection is disconnected, a connection with another channel is established , A delay time of several tens to several hundreds of milliseconds may be generated.

However, as described above, the conversational service provided by the LTE system is a real-time service. Therefore, when an interruption time occurs in a handover process, a real time service provided by a traffic loss There is a problem that the quality of the service may deteriorate.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-described conventional problems, and it is an object of the present invention to provide a method and apparatus for determining a transmission power of a random access preamble in a handover process.

The present invention has been proposed in order to solve the above-mentioned problems of the related art. In order to reduce the delay time in the handover process, the present invention provides a random access preamble with a transmission power magnitude from a previous transmission power magnitude, There is provided a method and apparatus for transmitting a random access preamble while increasing transmission power.

It is another object of the present invention to provide a method and apparatus for controlling a transmission power of a random access preamble according to a Quality of Service (QoS) class identifier having a highest priority among QCIs And to propose a method for determining the method.

It is another object of the present invention to provide a method and apparatus for setting a transmission power of a random access preamble for each quality of service class identifier to minimize quality degradation of a real- And to propose a method and apparatus therefor.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. Lt; / RTI >

According to another aspect of the present invention, there is provided a method for determining a transmission power of a random access preamble for a random access procedure in a handover procedure in a wireless communication system, The method includes receiving a handover request from a user equipment (UE) that is provided with a communication service, measuring a transmission power of a random access preamble according to a Quality of Service Class Identifier (QCI) And transmitting the information on the determined transmission power to the user terminal. The service quality class identifier has a priority set in advance for each of the quality of service class identifiers, Among service quality class identifiers of the service, the service quality with the highest priority It can be determined according to the class identifier.

In the method of determining the transmission power of the random access preamble of the present invention, the information on the transmission power may be included in the RRC Connection Reconfiguration (RRC) reconnection message and transmitted to the user terminal.

In the method of determining the transmission power of the random access preamble of the present invention, the information on the transmission power includes information on initial transmission power and Ramping used for setting retransmission power. ) ≪ / RTI > value.

In the method of determining the transmission power of the random access preamble of the present invention, the initial transmission power is set such that the transmission power of the random access preamble of the packet of the quality of service class identifier having the highest priority from the initial setting value predetermined for the highest- May be determined according to a value obtained by subtracting the value of the packet loss rate and adding a delta preamble value to the result.

In the method of determining the transmission power of the random access preamble of the present invention, the retransmission power may be set to be determined by adding a ramping value to the initial power whenever the number of times of retransmission increases.

A method for determining a transmission power of a random access preamble according to the present invention includes the steps of transmitting a handover request to a base station by a user terminal receiving a wireless communication service, Receiving information on the transmission power of an access preamble from a base station and transmitting a random access preamble for a random access procedure according to a transmission power included in information on received transmission power, The identifier has a preset priority for each of the quality of service class identifiers and the transmission power can be determined according to the highest quality of service quality class identifier among the service quality class identifiers of the wireless communication service.

In the method of determining the transmission power of the random access preamble of the present invention, the information on the transmission power may be received from the base station by being included in the radio resource control connection reestablishment message.

In the method of determining the transmission power of the random access preamble of the present invention, the information on the transmission power may include both information on the initial transmission power and information on the ramping value used for setting the retransmission power.

In the method of determining the transmission power of the random access preamble of the present invention, the initial transmission power is set such that the transmission power of the random access preamble of the packet of the quality of service class identifier having the highest priority from the initial setting value predetermined for the highest- May be determined according to a value obtained by subtracting the value of the packet loss rate and adding a delta preamble value to the result.

In the method of determining the transmission power of the random access preamble of the present invention, the retransmission power may be set to be determined by adding a ramping value to the initial power whenever the number of times of retransmission increases.

According to an aspect of the present invention, there is provided an apparatus for allocating a transmission power of a random access preamble according to a service quality class identifier of a wireless communication service, a memory unit, a receiver for receiving a handover request from a user terminal And a transmitter for transmitting information on the determined transmission power to the user terminal, wherein the control unit determines that the transmission power included in the information on the transmission power is higher than the transmission quality of the service It is possible to control so that the priority set in advance for each quality class identifier is determined according to the highest quality-of-service class identifier.

In the apparatus of the present invention, the controller may include information on the transmission power in a RRC Connection Reconfiguration (RRC Connection Reconfiguration) message so that the transmission unit transmits the RRC Connection Reconfiguration message.

In the apparatus of the present invention, the control unit may include both information on the transmission power and information on the initial transmission power and information on a ramping value used for setting the retransmission power. .

In the apparatus of the present invention, the initial transmission power is a value obtained by multiplying a value of a packet loss rate of a highest quality of service quality class identifier with a predetermined initial setting value for a highest priority QoS class identifier And then adding the delta preamble value to the result of the subtraction.

In the apparatus of the present invention, the retransmission power may be set to be determined by adding a ramping value each time the number of retransmissions increases with the initial power.

According to the present invention, it is possible to determine a transmission power of a random access preamble in a handover process.

In addition, according to the present invention, in the handover process, a random access channel preamble (RACH Preamble) is transmitted while the transmit power of the random access channel preamble is ran at the initial transmit power, The delay time in the over process can be reduced.

In addition, according to the present invention, the transmission power of the random access preamble can be determined according to the highest quality of service class identifier among the quality of service class identifiers of the wireless communication service.

In addition, according to the present invention, the transmission power of the random access preamble is set for each quality of service class identifier, thereby minimizing quality degradation of a real-time service such as an interactive service upon handover.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention.
2 is a flowchart illustrating a handover process according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of a contention-based random access procedure according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of a contention-free random access procedure according to an embodiment of the present invention.
5 is a diagram illustrating a method of transmitting a random access preamble according to an embodiment of the present invention.
6 is a diagram illustrating a method of transmitting a random access preamble according to an embodiment of the present invention.
7 is a diagram illustrating random access preamble transmission power according to an embodiment of the present invention.
8 is a block diagram illustrating an apparatus according to another embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. In the description of the drawings, there is no description of procedures or steps or the like that may obscure the technical gist of the present invention, nor are descriptions of steps or steps that can be understood at a level of ordinary skill in the art.

Throughout the specification, when an element is referred to as "comprising" or " including ", it is meant that the element does not exclude other elements, do. Also, the term "part" in the description means a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. Also, the terms " a or ", "one "," the ", and the like are synonyms in the context of describing the invention (particularly in the context of the following claims) May be used in a sense including both singular and plural, unless the context clearly dictates otherwise.

The specific terms used in the embodiments of the present invention are provided to facilitate understanding of the present invention, and the use of such specific terms may be changed into other forms without departing from the technical idea of the present invention.

1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 1, a wireless communication system 10 may include one or more user terminals 100a and 100b, a base station 200, and a network 120 for signal transmission and exchange between a terminal and a base station.

1, the wireless communication system according to an exemplary embodiment of the present invention may also include a repeater for amplifying and transmitting signals between the user terminals 100a and 100b and the base station 200. FIG.

The user terminals 100a and 100b can maintain a connection state with the base station 200 according to an embodiment of the present invention and can receive services.

In addition, the user terminals 100a and 100b may perform a handover procedure because they may be fixed or mobile. In the present invention, the user terminals 100a and 100b may be user equipment (UE), user terminal (UT) A wireless device, a terminal, and the like.

An example of the user terminals 100a and 100b may be a Wi-Fi phone, an IP (Internet Protocol) phone, an AP, an HGW (Home Gateways), a STB (Set Top Box) A mobile phone, a tablet PC, a smart phone, a cellular phone, a PCS (Personal Communication Service) phone, a GSM (Global System for Mobile) phone, a WCDMA (Wideband CDMA) A PDA (Personal Digital Assistants), and a PMP (Portable Multimedia Player). Of course, this is merely an example, and it should be construed as a concept including a device that is currently developed, commercialized, or capable of all communication to be developed in the future, in addition to the above-described examples.

The base station 200 generally refers to a fixed station that communicates with the user terminals 100a and 100b and may be a fixed station that is connected to a terminal before a handover procedure is performed according to an embodiment of the present invention. And a target base station that maintains a connection with the terminal after the handover procedure with the base station is completed.

In addition, the base station 200 may be referred to as other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, etc. One or more cells may exist in one base station 200, An interface for transmitting user traffic or control traffic may be used between the base stations.

The network 110 means a data communication network for transmitting data and messages and exchanging information between the user terminals 100a and 100b and the base station 200, and the type thereof is not particularly limited.

For example, it is possible to transmit and receive a large amount of data through an Internet Protocol (IP), an IP (Internet Protocol) service that provides a data service free from disconnection, It may be an All IP network.

In addition, the network 110 may include a mobile communication network including a wired network, a Wibro (Wireless Broadband) network, a WCDMA, a High Speed Downlink Packet Access (HSDPA) network and an LTE network, A network, and a Wi-Fi network.

2 is a flowchart illustrating a handover process according to an embodiment of the present invention.

2, when a UE 100 is connected to a base station 200 and a service is provided, the user terminal UE 100 moves out of a serviceable area of the base station 200 to a neighboring base station 300, There is a case in which the mobile terminal moves to a serviceable area of the mobile terminal.

In this case, the connection with the base station 200, which is connected to the user terminal 100 and is provided with the service, must be continued in connection with another adjacent base station 300, so that the user terminal 100 is continuously provided with the service At this time, a handover procedure for transferring the connection between the user terminal 100 and the base station becomes necessary.

A base station that is currently connected to the user terminal 100 and is currently provided with a service is referred to as a source base station 200 and a neighbor base station to be newly connected is referred to as a target base station 300, Quot;

The handover process consists of three stages: handover preparation, handover execution, and handover completion.

The handover process is performed from the step S201 of measuring the signal (s) of the neighboring base station from which the user terminal 100 is sensed and performing a measurement report on the measurement to the source base station 200 It starts.

Upon receiving the measurement report from the user terminal 100, the source base station 200 determines whether the user terminal 100 should perform a handover and which base station 200 performs handover to the target base station (Handover decision) to determine whether the handover is successful or not.

Meanwhile, if the source base station 200 determines handover of the terminal, the handover preparation procedure with the target base station 300 (S202) is performed.

2, the source base station 200 transmits a handover request message to the target BS 300 as a handover preparation procedure.

The handover request message is a message transmitted from the source base station 200 through the interface to request preparation of radio resources for handover to the target base station 300.

In addition, the handover request message may include various configuration information about a connection between the user terminal 100 and the source base station 200.

Meanwhile, as a step included in the handover preparation process (S202), the target base station 300 receiving the handover request message from the source base station 200 transmits the handover request message to the user terminal 100 through an admission control process. And transmits a handover request acknowledgment message to the source base station 200. The handover request acknowledgment message includes a resource allocation request message,

Here, the handover request response message is also transmitted from the target base station 300 to the source base station 200 through the interface, and the handover request response message is a response message to the handover request message described above.

In addition, the handover request response message is a message informing the source base station 200 of the prepared resource information for the user terminal 100 to be handed over by the target base station 300.

The handover request response message includes a radio resource control reconfiguration (RRC connection reconfiguration) message. The RRC connection re-establishment message includes a handover command to be transmitted to the user terminal 100 (Handover Command).

In step S202, the source base station 200 receives the handover request response message from the target base station 300 and transmits an RRC connection re-establishment message including a handover command to the user terminal 100 (S203).

Upon receiving the RRC connection re-establishment message from the source base station 200, the user terminal 100 performs a handover for connection to the target base station 300 through a random access procedure, Execution step is executed (S204).

The random access procedure will be described in more detail below as a procedure for the user terminal 100 to be connected to the target base station 300.

Meanwhile, if the user terminal 100 succeeds in handover to the target BS 300 through a random access procedure, the user terminal 100 performs RRC connection (handover completion) The RRC connection reconfiguration complete message is transmitted to the target BS 300 in step S205 and the target BS 300 having received the RRC connection reconfiguration completion message from the user terminal 100 completes the handover operation The handover procedure is terminated.

FIG. 3 and FIG. 4 are views showing an example of a contention-based random access procedure and a non-contention based random access procedure according to an embodiment of the present invention, respectively.

3 and 4, a contention based random access procedure is shown in FIG. 3 and a non-contention based random access procedure is shown in FIG. 4. The random access procedure is a competition based random access procedure and a non- .

3, it is assumed that the user terminal 100 performs a handover through a contention-based random access procedure. In the description related to FIG. 4, the user terminal 100 performs a non-contention based random access procedure It is assumed that the handover is performed through the base station.

Meanwhile, the contention-based random access procedure randomly selects a random access channel preamble transmitted by the user terminal 100 for connection with the target base station 300.

Accordingly, it is possible for a plurality of UEs to select the same random access preamble at the same time and transmit the selected random access preamble to the target base station, thereby requiring a contention resolution in the future.

As shown in FIG. 4, in the non-contention-based random access procedure, the BS performs a random access procedure using a random access preamble uniquely allocated to a corresponding user terminal, The random access procedure can be performed without collision.

That is, the greatest difference between the contention-based random access procedure and the non-contention-based random access procedure is whether the random access preamble is dedicated to one UE.

In the non-contention-based random access procedure, since a user terminal uses a dedicated random access preamble assigned only to itself, no contention (or collision) with other user terminals occurs, while contention-based random access causes one or more random access pre- There is a possibility of a contention because the UE uses randomly selected random access preambles.

Here, the competition means that two or more UEs attempt random access procedures using the same random access preamble through the same resource.

Returning to FIG. 3, the user terminal 100 receiving the RRC connection re-establishment message from the source base station 200 performs a contention-based random access procedure for performing the handover.

3, it is assumed that the user terminal 100 randomly determines a predetermined random access preamble to perform a contention-based random access procedure.

According to an embodiment of the present invention, the user terminal 100 transmits a random access preamble as an initial transmission power to the target base station 300 in order to perform a contention-based random access procedure (S301).

In this case, the transmission power means a power amount used by the user terminal 100 to transmit the random access preamble to the target base station 300, and the initial transmission power is used to transmit the random access preamble first Quot; power "

In addition, the initial transmission power is determined in the base station 200 as described below, and the user terminal receives a parameter including the determined initial transmission power value or the initial transmission power value from the base station.

A UE receiving a parameter including an initial transmission power value determines an initial transmission power for transmitting a random access preamble based on information included in a received parameter.

More specifically, the base station determines the transmission power for transmitting the random access preamble according to the quality of service (QoS) class identifier of the wireless communication service using the quality of service class identifier shown in Table 1 below.

QCI Resource
Type Priority Packet delay  budget ( ms ) Packet
Loss Rate Services One GBR 2 100 10 ^-2 Conversational voice 2 4 150 10 ^-3 Conversational video (live streaming) 3 3 300 10 ^-6 Non-conversational video (buffered streaming) 4 5 50 10 ^-3 Real time gaming 5 Non-GBR One 100 10 ^-6 IMS signaling 6 6 100 10 ^-3 Voice, video (live streaming), interactive gaming 7 7 300 10 ^-6 Video (buffered streaming) 8 8 300 10 ^-6 TCP-based (WWW, e-mail, chat, FTP, p2p, file sharing, progressive video, etc.) 9 9 333 10 ^-6

Table 1 is a table showing a quality of service (QoS) class identifier (QCI) and a priority of a wireless communication service according to an exemplary embodiment of the present invention.

Referring to Table 1, a wireless communication service provided in a wireless communication system is illustrated, and a Quality of Service Class Identifier (QCI) of each wireless communication service is expressed.

Here, the quality of service class identifier (QCI) is a service quality class identifier (QCI) that classifies each service provided in a wireless communication system such as voice, video, data, and real-time service by classifying the service according to quality, It means a way to classify services to enable quality management.

Each of the wireless communication services is assigned a priority in consideration of the amount of traffic used for providing the service, and a service having the highest amount of traffic used for service provision (for example, In Table 1, Conversational Service is given a higher priority and relatively lower priority is given to services with a relatively small amount of traffic used for service provisioning.

When the wireless communication resources are limited within the wireless communication system and the number of services to be provided to the user terminal is one or more, the priority determined in this way is a service having the highest amount of traffic used for service provision, It can be used for providing services by allocating limited wireless communication resources sequentially from a high service, thereby maintaining the quality of each service.

Meanwhile, in the process of providing each wireless communication service to the user terminal on a packet basis, a packet may be lost due to a failure or an error.

That is, the value of the packet loss rate in Table 1 means that the amount of packets lost due to a failure or error in the process of providing each wireless communication service to the user terminal is numerically expressed, and the packet loss rate May be different for each wireless communication service.

Meanwhile, as described above, the user terminal 100 transmits the random access preamble with the initial transmission power to the target base station 300 to perform the contention-based random access procedure, and the initial transmission power is transmitted to the base station 200 ) According to the quality of service class identifier of the wireless communication service.

That is, when the base station 200 receives the measurement report of the signal (s) of the neighboring base station from the user terminal 100 in step S201 of FIG. 2, the base station 200 confirms one or more wireless communication services And determines an initial transmission power for the user terminal to transmit the random access preamble using the service quality class identifier of the at least one wireless communication service.

According to a preferred embodiment of the present invention, when there are two or more wireless communication services currently provided by the user terminal, a service quality class identifier having the highest priority among the service quality class identifiers of the two or more wireless communication services, The initial transmission power can be determined.

Also, according to a preferred embodiment of the present invention, when there are two or more wireless communication services currently provided to the user terminal, the service quality class identifiers of the two or more wireless communication services are used in the following description The initial transmission power may be determined as the final initial transmission power value by using the highest quality of service class identifier among the service quality class identifiers of the two or more wireless communication services.

In addition, according to a preferred embodiment of the present invention, when there is one wireless communication service currently provided to the user terminal, the service quality class identifier is assigned to the wireless communication service as a service quality class identifier having the highest priority The initial transmission power can be determined using the quality of service class identifier.

At this time, the initial transmission power is obtained by subtracting the packet loss ratio value of the selected quality of service class identifier from a predetermined initial setting value for the selected quality of service class identifier, as shown in FIG. 5, and then adding a delta preamble (500), which is a value obtained by summing the values.

Here, the value of the delta preamble is for canceling the packet loss ratio value described above, and is determined to be the same value as the packet loss ratio value of the service quality class identifier.

In addition, the predetermined initial setting value for each quality of service class identifier is determined according to any one of the values shown in Table 2 below. Preferably, when the priority of the quality of service class identifier is the highest, It can be set to the initial setting value (dBm -90 in Table 2 below).

Initial setting dBm -120, dBm-118, dBm-116, dBm-114, dBm -112
dBm -110, dBm -108, dBm -106, dBm -104, dBm -102
dBm-92, dBm-90

     However, the range of the initial set values disclosed in Table 2 is only one example, and the range of the initial set values is not limited to the range disclosed in Table 2. [ It is also possible to change or set the range of the initial set values disclosed in Table 2 in various ways well known in the art.

As described above, according to an embodiment of the present invention, the base station determines initial transmission power for a user terminal to transmit a random access preamble according to a service quality class identifier of a wireless communication service provided by the user terminal do.

In addition, the base station may transmit a parameter including information on the determined initial transmission power to the user terminal in the RRC connection re-establishment message, and the user terminal may transmit a random access procedure for the random access procedure according to the initial transmission power included in the received parameter. And transmits the random access preamble to the target base station.

3, when the target base station 300 receives the random access preamble transmitted from the user terminal 100, the target base station decodes the received preamble. If the target base station 300 successfully decodes the random access preamble, Random Access Response) message to the user terminal 100 (S302).

However, if the target base station 300 fails to receive or decode the random access preamble transmitted from the user terminal 100, the target base station 300 transmits a random access response message to the user terminal 100 Can not.

According to an exemplary embodiment of the present invention, the user terminal 100 transmits a random access preamble to the target base station 300 in a size of initial transmission power included in a parameter received from the base station, and then transmits a random access response It is possible to transmit the random access preamble to the target base station 300 again with the size of the retransmission power.

If the target BS does not transmit the random access response message even after the user terminal 100 retransmits the random access preamble with the retransmission power, that is, if the user terminal 100 continues to transmit the random access response message It is possible to retransmit the random access preamble to the target base station 300 at predetermined time intervals, and the retransmission may be repeated a predetermined number of times.

Here, if the UE 100 does not receive the random access response message from the target BS even after initial transmission or retransmission of the random access preamble to the target BS, Refers to transmission powers 501 and 502 that are ramped up by a predetermined value from the transmission power magnitude at the time of transmission or retransmission, and the transmission power value used for transmitting the immediately preceding random access preamble, Is determined by the sum of the ramping values.

That is, as shown in FIG. 5, the retransmission power may be continuously increased (501, 502) by a predetermined ramping value every time the number of times of retransmission increases, according to an embodiment of the present invention. The predetermined value to be ramped may be ramped to the same value each time the number of retransmissions increases, or may be ramped to a non-identical value.

Hereinafter, a process for determining retransmission power will be described in more detail.

If the UE 100 does not receive the random access response for a predetermined time after transmitting the random access preamble to the target BS 300 with the initial transmission power included in the parameter received from the BS, Transmits the random access preamble to the target base station 300 with retransmission power ramped by a predetermined ramping value from the transmission power, and the predetermined ramping value is transmitted from the base station 200 to the service quality class identifier QCI).

That is, according to an embodiment of the present invention, when the base station 200 receives the measurement report of the signal (s) of the neighboring base station from the user terminal 100 in step S201 of FIG. 2, And determines the predetermined ramping value using the service quality class identifier of the one or more wireless communication services.

According to a preferred embodiment of the present invention, when there are two or more wireless communication services currently provided by the user terminal, a service quality class identifier having the highest priority among the service quality class identifiers of the two or more wireless communication services, The predetermined ramping value can be determined.

Also, according to a preferred embodiment of the present invention, when there are two or more wireless communication services currently provided to the user terminal, the service quality class identifiers of the two or more wireless communication services are used in the following description Determining a predetermined ramping value determined using the service quality class identifier having the highest priority among the service quality class identifiers of the two or more wireless communication services as the final predetermined ramping value have.

According to a preferred embodiment of the present invention, when there is one wireless communication service currently provided to the user terminal, the service quality class identifier of the wireless communication service is regarded as the service quality class identifier having the highest priority The predetermined ramping value can be determined using the quality of service class identifier.

Meanwhile, the user terminal retransmits the random access preamble to the target base station 300 with the retransmission power set using the transmission power value used for transmitting the immediately preceding random access preamble and the predetermined ramping value determined previously .

Also, as shown in FIG. 6, the retransmission can be repeated a predetermined number of times. When the number of retransmissions increases by one in accordance with the embodiment of the present invention, . ≪ / RTI >

Here, the predetermined ramping value that is ramped in the retransmission may be determined according to any one of the values shown in Table 3 below. Preferably, the priority of the quality of service class identifier disclosed in Table 1 is the highest , The largest ramping value of the ramping values disclosed in Table 2 (dB 6 in Table 3 below) can be set.

Ramping ( Ramping ) Value dB 0, dB 2, dB 4, dB 6

     However, the predetermined ramping value that is ramped in the re-transmission disclosed in Table 3 is only one example, and the predetermined ramping value to be ramped is not limited to the contents disclosed in Table 3. [ It is also possible to vary or set the ramping ramping values disclosed in Table 3 in a number of ways well known in the art.

Meanwhile, the predetermined ramping value to be ramped is determined according to the above-described method in the base station 200, and the user terminal can receive a parameter including the determined predetermined ramping value from the base station.

Also, the user terminal can determine the retransmission power according to a predetermined ramping value included in the received parameter, and retransmit the random access preamble to the target base station with retransmission power.

According to an embodiment of the present invention, the parameter including the predetermined ramping value may be included in the RRC connection re-establishment message received from the base station 200 and transmitted to the user terminal, and the RRC connection The reset message may include a parameter including the initial transmission power value described above in addition to the parameter including the predetermined ramping value.

3, when the user terminal 100 receives the random access response message from the target base station 300 (S302), the user terminal 100 stops the transmission of the random access preamble and determines that the connection is established A Schedule Transmission message is transmitted (S303).

In step S303, the target base station 300 receiving the schedule transmission message from the user terminal 100 transmits a contention resolution message to the user terminal 100 (S304).

The Contention Resolution message is a response message to the schedule transmission message received from the user terminal 100 in step S303, indicating that the contention with other user terminals is terminated.

FIG. 4 is a diagram illustrating an example of a contention-free random access procedure according to an embodiment of the present invention.

4, unlike the contention-based random access procedure of FIG. 3, in the non-contention-based random access procedure, the target base station 300 transmits random access to the user terminal 100, And allocates a preamble (S401).

The user terminal 100 transmits a random access preamble to the target UE 300 using the initial transmission power or the retransmission power determined in the same manner as described above with reference to FIG. 3 using the random access preamble allocated by the target base station 300 in step S401. And transmits the random access procedure to the base station 300 (S402).

As a result, the user terminal can perform the random access procedure without conflict with other user terminals, unlike the contention-based random access procedure described in FIG.

Meanwhile, when the user terminal 100 receives a random access response message from the target base station 300 in response to the random access preamble transmitted in step S402, the connection between the user terminal and the target base station is established (S403) .

 7 is a diagram illustrating random access preamble transmission power according to an embodiment of the present invention.

7, the initial transmission power 702 and the ramping value 701 that the user terminal 100 uses to transmit the random access preamble to the target base station 300 may be determined based on the initial transmission power 702 and the ramping value 701, And is determined according to the quality of service class identifier of the wireless communication service in the base station 200 as described above with reference to Figs.

7, the initial transmission power value for transmitting the random access preamble to the user terminal 100 is dBm -110, and the retransmission power is set to < RTI ID = 0.0 > The ramping value for the determination is assumed to be an initial value, each set to dB 2.

More specifically, when the base station 200 receives the measurement report of the signal (s) of the neighboring base station from the user terminal 100 in step S201 of FIG. 2, And determines an initial transmission power and / or a predetermined ramping value for the user terminal to transmit the random access preamble using the service quality class identifier of the at least one wireless communication service.

 At this time, if the user terminal has two or more wireless communication services currently being provided and the priority 703 of the quality of service class identifiers (QCI, 700a and 700b) of the two or more wireless communication services is QCI 1 703a, , And QCI 2 703b, it is assumed that the initial transmission power (dBm -100) is calculated using the highest quality of service class identifier 700a among the service quality class identifiers 700a and 700b of the two or more wireless communication services, ) And the ramping value (dB 6).

In this case, the initial transmission power value is increased by dBm 10, and the ramping value is increased by dB 4 than the initial transmission power value of dBm -110 and the ramping value for determining retransmission power of dB 2, respectively. There is an effect that the transmission power value is increased by a total of dB 14 in comparison with the value of the transmission power.

Also, according to a preferred embodiment of the present invention, it is assumed that there are more than two wireless communication services currently being provided by the user terminal, and the priority of the quality of service class identifiers (QCI, 700a and 700b) of each of the two or more wireless communication services And 703 are QCI 1 703 a and QCI 2 703 b, respectively, using the service quality class identifiers 700 a and 700 b of the two or more wireless communication services, (dBm -100, dBm-105) and a ramping value (dB 6, dB 4), wherein the service quality class identifier (700a, 700b) of each of the two or more wireless communication services, The initial transmission power (dBm -100) and the ramping value (dB 6) determined using the initial transmission power value (dBm -100) and the ramping value (dB 6) determined using the initial transmission power value 700a may be determined.

In this case, the initial transmission power value is increased by dBm 10, and the ramping value is increased by dB 4 than the initial transmission power value of dBm -110 and the ramping value for determining the retransmission power of dB 2, respectively. There is an effect that the transmission power value is increased by a total of about 14 dB compared to the case of FIG.

Also, according to a preferred embodiment of the present invention, when there is one wireless communication service currently provided to the user terminal (for example, a QCI 2 (700b) communication service), the service quality class identifier It is possible to determine the initial transmission power (dBm-105) and the ramping value (dB 4) by using the service quality class identifier 700b with the service quality class identifier 700b having the highest priority as the service quality class identifier 703b having the highest priority.

In this case, the initial transmission power value is increased by dBm 5, and the ramping value is increased by dB 2 than the initial transmission power value of dBm -110 and the ramping value for determining retransmission power of dB 2, respectively. There is an effect that the transmission power value is increased by the total dB 7 compared to the case of FIG.

8 is a block diagram illustrating an apparatus according to another embodiment of the present invention.

Referring to FIG. 8, a wireless communication system according to an embodiment of the present invention includes a base station 900 and an apparatus 800 according to one embodiment of the present invention located within a base station 900 area.

Also, a plurality of devices 800 in accordance with one embodiment of the present invention located within the base station 900 and base station 900 areas shown in FIG. 8 implement the functions, processes, and / or methods proposed herein, It is possible to combine at least one or two or more of the embodiments (s) of the present invention described above.

The apparatus 800 according to an exemplary embodiment of the present invention includes a processor 801, a radio frequency unit 802 including a transmitter and a controller, and a memory 803 And processor 801 may implement the functions, processes, and / or methods suggested in the present invention.

The memory 803 may store the initial transmission power and the ramping value for transmitting the random access preamble according to the present invention and may load the initial transmission power and the ramping value under the control of the processor 801 (Hereinafter referred to as "temporary memory") (not shown), and the temporary memory may be configured separately from the memory.

The temporary memory may refer to a volatile memory (e.g., RAM (Random Access Memory)) that temporarily stores data while the apparatus 800 is powered on according to an embodiment of the present invention.

The memory 803 is connected to the processor 801 and stores various information for driving the processor 801. [ The RF unit 802 including a transmitter and a receiver may be connected to the processor 801 to transmit and / or receive a radio signal.

The device 800 according to an embodiment of the present invention may be fixed or mobile and may be called by various other terms such as User Equipment (UE), User Terminal (UT), and Wireless Device.

A notebook PC, a mobile phone, a tablet PC, a smart phone, a cellular phone, a personal communication service (PCS), a personal digital assistant (PDA) (Global System for Mobile) phone, a WCDMA (Wideband CDMA) phone, a Mobile Broadband System (MBS) phone, a Personal Digital Assistants (PDA), and a Portable Multimedia Player (PMP). Of course, this is merely an example, and it should be construed as a concept including a device that is currently developed, commercialized, or capable of all communication to be developed in the future, in addition to the above-described examples.

The base station 900 refers to a fixed station for communicating and transmitting / receiving data with the apparatus 800 according to an embodiment of the present invention. The base station 900 may include a base transceiver system (BTS), an access point, It can be called Terminology.

The base station 900 may also include a processor 901, an RF unit 802 and a memory 903 and the processor 901 may implement the functions, processes and / or methods suggested by the present invention.

The memory 903 may be coupled to the processor 901 to store various information for driving the processor 901 and the RF unit 902 may be coupled to the processor 901 to transmit and / can do.

The memories 803 and 903 may be internal or external to the processors 801 and 901 and may be coupled to the processors 801 and 901 by various well known means.

In addition, the apparatus 800 and / or the base station 900 according to an embodiment of the present invention may have a single antenna or multiple antennas.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in memory and driven by the processor. The memory is located inside or outside the processor and can exchange data with the processor by various means already known.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. Accordingly, the foregoing detailed description is to be considered in all respects illustrative and not restrictive. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

The method and apparatus for determining the transmission power of the random access preamble of the present invention can be applied to various systems and apparatus to which a random access preamble is applied.

800: device 900: base station
801: Processor 901: Processor
802: RF unit 902: RF unit
803: memory 903: memory

Claims (15)

A method for determining a transmission power of a random access preamble for a random access procedure in a handover procedure in a wireless communication system,
Receiving a handover request from a user equipment (UE) that is provided with a wireless communication service;
Setting information on the transmission power of the random access preamble according to a Quality of Service Class Identifier (QCI) of the wireless communication service; And
And transmitting information on the determined transmission power to the user terminal,
The service quality class identifier has a priority set in advance for each quality of service class identifier,
Wherein the transmission power is determined according to a quality of service (QoS) class identifier having the highest priority among service quality class identifiers of the wireless communication service. The method according to claim 1,
Wherein the information about the transmission power is included in a RRC Connection Reconfiguration (RRC) reconnection message and is transmitted to the user terminal. The method according to claim 1,
Wherein the information on the transmission power includes both information on an initial transmission power and information on a ramping value used for setting a retransmission power. A method for determining a transmission power of a preamble. The method of claim 3,
The initial transmission power is obtained by subtracting the value of the packet loss rate of the highest quality of service class identifier from the initial set value predetermined for the highest quality of service class identifier with the highest priority, And determining a transmission power of the random access preamble based on a value obtained by adding a delta preamble value to the result. The method of claim 3,
Wherein the retransmission power is set to be determined by adding the ramping value to the initial power whenever the number of retransmissions increases. A method for determining a transmission power of a random access preamble for a random access procedure in a handover procedure in a wireless communication system,
The method comprising: transmitting a handover request to a user equipment (UE), which is provided with a wireless communication service, to a base station;
Receiving information on a transmission power of the random access preamble determined by the base station from the base station according to a Quality of Service Class Identifier (QCI) of the wireless communication service; And
And transmitting a random access preamble for the random access procedure according to a transmission power included in information on the received transmission power,
Wherein the service quality class identifier has a priority set in advance for each of the quality of service class identifiers and the transmission power is determined according to a service quality class identifier having the highest priority among the service quality class identifiers of the wireless communication service And determining a transmission power of the random access preamble. The method according to claim 6,
Wherein the information about the transmission power is included in a RRC Connection Reconfiguration (RRC) reconnection message and is received from the base station. The method according to claim 6,
Wherein the information on the transmission power includes both information on an initial transmission power and information on a ramping value used for setting a retransmission power. A method for determining a transmission power of a preamble. 9. The method of claim 8,
The initial transmission power is obtained by subtracting the value of the packet loss rate of the highest quality of service class identifier from the initial set value predetermined for the highest quality of service class identifier with the highest priority, And determining a transmission power of the random access preamble based on a value obtained by adding a delta preamble value to the result. 9. The method of claim 8,
Wherein the retransmission power is set to be determined by adding the ramping value to the initial power whenever the number of retransmissions increases. 1. An apparatus for determining a transmission power of a random access preamble for a random access procedure in a handover procedure in a wireless communication system,
A memory unit;
A receiver for receiving a handover request from a user equipment (UE) receiving a wireless communication service;
A control unit configured to set information on the transmission power of the random access preamble according to a Quality of Service Class Identifier (QCI) of the wireless communication service; And
And a transmitter for transmitting information on the determined transmission power to the user terminal,
The control unit controls the transmission power included in the information on the transmission power to be determined in accordance with a service quality class identifier having a highest priority set in advance for each of the quality of service class identifiers of the wireless communication service / RTI > 12. The method of claim 11,
Wherein the control unit controls the transmission unit to transmit information on the transmission power in a radio resource control reconfiguration (RRC Connection Reconfiguration) message. 12. The method of claim 11,
The control unit controls the information on the transmission power so as to include both information on initial transmission power and information on a ramping value used for setting a retransmission power . 14. The method of claim 13,
The initial transmission power is obtained by subtracting the value of the packet loss rate of the highest quality of service class identifier from the initial set value predetermined for the highest quality of service class identifier with the highest priority, Is determined according to a value obtained by adding a delta preamble value to the result. 14. The method of claim 13,
Wherein the retransmission power is set to be determined by adding the ramping value every time the number of retransmissions increases with the initial power.

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