KR100913889B1 - Apparatus and method for handover in wireless system - Google Patents

Abstract

The present invention is a handover method by a base station for servicing an uplink timing-synchronized terminal for a target cell in a mobile communication system. Determining whether the allocation cycle is larger than a predetermined threshold; and if the base station of the source cell is larger than the predetermined threshold, configuring the scheduling request / channel quality information / sounding transmission resource information in two steps; Including the scheduling request / channel quality information / sounding transmission resource information in the handover command message and transmitting the information to the terminal, and the base station of the target cell via the first scheduling request / channel quality information / sounding transmission resource When the control information is received from the terminal, the handover complete message is transmitted to the terminal. The process involves allocating a radio resource.

UL timing sync, Handover Command, Handover Confirm, 2step SR / CQI / Sounding radio resource

Description

Handover method and apparatus of mobile communication system {APPARATUS AND METHOD FOR HANDOVER IN WIRELESS SYSTEM}

1 is a diagram illustrating an example of configuration of a 3GPP LTE system.

2A is a diagram for explaining a propagation delay time difference in an OFDM multiplexing system.

2B is a diagram illustrating a state before an uplink signal from a terminal is sinked according to a propagation delay time difference in an OFDM multiplexing system.

2c is a diagram illustrating a state after an uplink signal from a terminal is synchronized according to a propagation delay time difference in an OFDM multiplexing system;

3 is a signal flow diagram illustrating a handover method requiring an uplink timing sync procedure for a target cell according to an embodiment of the present invention.

4 is a signal flow diagram illustrating a handover method without an uplink timing sync procedure for a target cell according to another embodiment of the present invention.

5 is a signal flow diagram illustrating an eNB operation according to another embodiment of the present invention.

6 is a signal flow diagram illustrating the operation of a terminal according to another embodiment of the present invention.

7 is an internal configuration block diagram of an eNB according to another embodiment of the present invention.

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

The present invention relates to a handover method and apparatus of a terminal in a mobile communication system, and more particularly, to a handover method and apparatus that does not require an uplink timing synchronizer.

The UMTS system is based on the Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), a European mobile communication system, and uses Code Division Multiple Access (CDMA). The third generation asynchronous mobile communication system used. 3GPP, which is in charge of UMTS standardization, is discussing the Long Term Evolution (LTE) system as the next generation mobile communication system of the UMTS system. LTE is a technology for implementing high-speed packet-based communication having a transmission rate of up to 100 Mbps with a target of commercialization in 2010. To this end, various methods are discussed. For example, a method of reducing the number of nodes located on a communication path by simplifying a network structure, or approaching wireless protocols as close as possible to a wireless channel are under discussion.

1 illustrates an example of a structure of a next generation (Evolved) UMTS mobile communication system to which the present invention is applied.

Referring to FIG. 1, an Evolved UMTS Radio Access Network (hereinafter referred to as an 'E-UTRAN') 110 is an evolved Node B (hereinafter referred to as an 'eNB') 120, 122, and 124. 126, 128 and the anchor node 130, 132 is simplified to a two-node structure. The user equipment (hereinafter referred to as 'UE' or 'terminal') 101 connects to the Internet Protocol (hereinafter referred to as 'IP') network by the E-UTRAN 110. The eNBs 120 to 128 correspond to an existing node ratio (Node B) of the UMTS system and are connected to the UE 101 by a radio channel. Unlike the existing Node B, the eNBs 120 to 128 play a more complex role. In LTE, all user traffic including a real-time service such as Voice over IP (VoIP) over the Internet protocol is serviced through a shared channel, and thus, an apparatus for collecting and scheduling situation information of UEs is needed. 120 to 128 are in charge. One eNB typically controls a number of cells. In addition, the eNB performs Adaptive Modulation & Coding (hereinafter referred to as 'AMC') to determine a modulation scheme and a channel coding rate according to the channel state of the terminal, and performs HSDPA (UMTS) of UMTS. HARQ (Hybrid ARQ) is performed between the eNBs 120 to 128 and the UE 101 in LTE, such as High Speed Downlnk Packet Access (HSUPA) and High Speed Uplink Packet Access (E-DCH: also called Enhanced Dedicated Channel). Since HARQ alone cannot satisfy the requirements of various Quality of Service (QoS), a separate outer ARQ at the upper layer may be performed between the terminal 101 and the eNBs 120 to 128. Can be. Here, HARQ is a technique of increasing the reception success rate by soft combining with the retransmitted data without discarding previously received data, and is used in high-speed packet communication such as HSDPA (High Speed Downlink Packet Access) and EDCH (Enhanced Dedicated Channel). It is used to increase the transmission efficiency. To achieve transmission rates up to 100Mbps, LTE is expected to use Orthogonal Frequency Division Multiplexing (OFDM) as the radio access technology in the 20 MHz bandwidth.

2A to 2C are diagrams for explaining a necessity and a role of an uplink timing synchronization procedure in a 3GPP LTE system using an OFDM multiplexing scheme.

Referring to FIG. 2A, UE1 (hereinafter referred to as terminal 1) 210 represents a terminal located close to ENB 200, and UE2 (hereinafter referred to as terminal 2) 220 is located far from ENB 200. Represents a terminal. T_pro1 215 represents a propagation delay time in radio transmission from ENB 200 to terminal 1 210, and T_pro2 225 is from ENB 200 to terminal 2 220. The propagation delay time in radio transmission is shown. Since terminal 1 210 is located closer to ENB 200 than terminal 2 220, it can be seen that propagation delay time is relatively small.

Accordingly, when the terminal 1 210 and the terminal 2 220 are in a power on state or in an idle mode in one cell of the eNB, the terminal 1 210, the terminal 2 220, and the ENB 200 may be used. The uplink timing sinks of terminals in a cell that are detected by the DETECT DELL do not match.

FIG. 2B is a diagram illustrating a state before an uplink signal from a terminal is synchronized according to a propagation delay time difference in an OFDM multiplexing system. Referring to FIG. 2B, in consideration of the propagation delay time of the uplink transmission of the terminal 1 210 and the terminal 2 220, timings in the ENB for receiving the uplink OFDM symbol are 241, 242, and 243.

That is, the uplink symbol 231 of the terminal 1 is received at the ENB at the timing of 241 with the propagation delay time 215 of T_pro 1, and the uplink symbol 232 of the terminal 2 has the propagation delay time of 242. Is received at the ENB. Since the uplink symbols of FIG. 2B are before the uplink timing sync for terminal 1 and terminal 2, the ENB receives the uplink OFDM symbol and starts timing 241 to decode and receives the OFDM symbol from terminal 1. It can be seen that the timing 242 and the timing 243 for receiving the OFDM symbol from the terminal 2 are different. However, in this situation, since the uplink symbols 242 and 243 transmitted from the terminal 1 210 and the terminal 2 220 do not have orthogonality with each other and thus act as interference with each other, ENB Due to the timing of receiving an uplink symbol that does not coincide with the interference, a problem arises in that the uplink symbols transmitted from the terminal 1 and the terminal 2 cannot be successfully decoded.

The uplink timing sync process is a process of equally matching uplink symbol reception timing of the terminal 1, the terminal 2, and the ENB, and an example thereof is illustrated in FIG. 2C. At the end of the uplink timing sync process, start timing 251 for receiving and decoding the E-NB and uplink OFDM symbols, timing 252 for receiving the uplink OFDM symbols from terminal 1, and uplink OFDM from terminal 2 Timing 253 for receiving the symbols is synchronized as shown in FIG. 2C. When the timings are synchronized, the uplink symbols transmitted from the terminal 1 210 and the terminal 2 220 may maintain orthogonality, and the ENB may store the uplink symbols transmitted from the terminal 1 210 and the terminal 2 220. Can decode successfully.

By the way, as described above, techniques for aligning the uplink timing during handover have been discussed, but no specific method has been proposed.

Meanwhile, when the terminal completes the handover to the target cell, a resource for transmitting a message for notifying the completion of the handover to the target cell should be allocated. However, until now, after the source cell transmits the handover command message to the terminal, a specific method for allocating a radio resource for transmitting the handover complete message to the terminal by the eNB of the target cell is not presented.

Accordingly, an object of the present invention for overcoming the problem as described above proposes an uplink timing sync method and apparatus for a target cell in the handover of the terminal.

Another object of the present invention is to propose a method and apparatus for allocating resources for transmitting a message for notifying a target cell of handover completion when the terminal completes handover to a target cell.

It is still another object of the present invention to minimize the radio resources reserved for handover completion message transmission at the time of handover for which no uplink timing procedure is required for the target cell, and at the same time, the handover interruption time that occurs during handover. To provide a method and apparatus for reducing the.

An embodiment of the present invention for achieving the above object is a handover method by a base station for serving a terminal uplink timing-synchronized for a target cell in a mobile communication system, the base station of the source cell scheduling the reconfiguration for the terminal Determining whether the allocation cycle of the request / channel quality information / sounding transmission resource is greater than a predetermined threshold; and if the base station of the source cell is larger than the predetermined threshold, the two-step scheduling request / channel quality information / After configuring the sounding transmission resource information, including the two-step scheduling request / channel quality information / sounding transmission resource information in the handover command message and transmitting to the terminal, the base station of the target cell / When the control information is received from the terminal through the channel quality information / sounding transmission resource, Allocating a radio resource for transmitting the handover complete message to the terminal.

According to another embodiment of the present invention to achieve the above object, in the mobile communication system, a handover command message is received in the handover command message according to a successful handover method of an uplink timing-synchronized terminal for a target cell. A step of checking whether the step scheduling request / channel quality information / sounding transmission resource information is included; and if the second step scheduling request / channel quality information / sounding transmission resource information is included, the scheduling request / The scheduling request / channel quality information of the first step according to the process of transmitting the corresponding control information using the channel quality information / sounding transmission resource information and the control information for allocating the radio resource for transmitting the handover completion message. Release the sound transmission resource and control information using the scheduling request / channel quality information / sound transmission resource of the second step. It includes the process of transmitting.

According to another embodiment of the present invention for achieving the above object, a channel for managing basic information for determining handover to a base station apparatus supporting handover of an uplink timing-synchronized terminal for a target cell in a mobile communication system A handover decision unit for determining whether a terminal is handed over using a status report management unit, information received from the channel state report management unit, and a handover according to a handover decision signal output from the handover decision unit. In addition to the generation of the command, according to the frequency of the scheduling request / channel quality information / sounding transmission resources reconstructed in the target cell, two-stage scheduling request / channel quality information / sounding transmission resource information is configured and included in the handover command message A message manager for outputting a message and a handover command message output from the message manager; It includes a transceiver for converting and outputting a radio signal for transmission to the terminal.

Another embodiment of the present invention for achieving the above object is a handover command message received as a radio signal from the base station to the terminal performing a handover in the uplink timing sync with the target cell in the mobile communication system A transceiver for converting and outputting a message, and a message analyzer for detecting and outputting a scheduling request / channel quality information / sounding transmission resource information in a target cell after receiving and interpreting a handover command message from the transceiver; When receiving the two-stage scheduling request / channel quality information / sounding transmission resource information from the transmission and reception unit, according to the scheduling request / channel quality information / sounding transmission resource information of the first step, generating the corresponding control information to the transceiver And an SR / CQI / Sounding generation unit for outputting.

Hereinafter will be described with reference to the accompanying drawings in accordance with an embodiment of the present invention. Specific details are set forth in the following description, which is provided to aid a more general understanding of the invention. Those skilled in the art will recognize that the disclosed concept and specific embodiments of the invention described below may be changed or modified to achieve the technical problem to be achieved by the present invention. Those skilled in the art will also recognize that concepts and structures equivalent to the concepts and structures disclosed herein do not depart from the spirit and scope of the broadest form of the invention. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention provides an uplink timing synchronization scheme for a target cell during handover of the terminal and, when the terminal completes handover to the target cell, allocates resources for transmitting a message for notifying the target cell of the handover completion. Suggest a solution.

In addition, the present invention proposes two embodiments in allocating resources to be used for transmitting a message for notifying a target cell of handover completion.

The first embodiment includes information for allocating a separate handover complete message transmission resource in an uplink timing sync information message for a target cell during handover.

In the second embodiment, a reconfiguration scheduling request / channel quality information / sounding transmission resource for a terminal is allocated without handing a separate handover completion message transmission resource when a handover does not require an uplink timing procedure for a target cell. Send a handover complete message.

3 is a signal flow diagram illustrating a handover process requiring an uplink timing sync procedure for a target cell according to an embodiment of the present invention with reference to FIG. 3. Is a diagram illustrating a handover procedure when the uplink timing of the P2 is different from the uplink timing of the source cell.

Referring to FIG. 3, the terminal 301 sends a channel state measurement report to the source cell 303 in step 310. The channel state measurement report is to measure the channel state for the current cell and the neighbor cell according to the configuration (specific event or periodic) set by the eNB of the source cell 303, and informs the result of the channel state information. Based on the eNB in step 320 determines whether the handover of the terminal. If the eNB of the source cell determines to hand over the terminal 301 to the destination cell 305 in step 320, the source cell 303 transmits a handover command message to the terminal 301 in step 330. To instruct a handover to the destination cell 305. In this case, the handover command message includes cell ID information of the target cell, and radio channel reconfiguration information that is reconfigured for use by the terminal in the target cell. The radio channel reconfiguration information may be used by the terminal in radio resource information for transmitting a scheduling request (SR), channel quality information (CQI), sounding, etc. in the target cell. Terminal ID (C-RNTI: Cell Radio Network Temporary Id) and the like. The scheduling request is control signaling for informing that the terminal has data / messages to be transmitted to the transmission buffer and requesting allocation of radio resources for transmission of a specific buffer status report. Is to efficiently allocate downlink radio resources for the terminal by reporting the status or characteristics of the downlink channel. For example, the modulation and coding scheme (MCS) level setting of downlink transmission is performed based on channel quality information. The sounding is an uplink reference signal transmitted by a terminal and transmitted through a full band or a promised required band, and the ENB measures an uplink channel state of the terminal and efficiently uplink transmission resources in accordance with the measurement result. Used to assign

When the terminal receives the handover command message in step 330, the terminal transmits a preamble, which is a series of code sequences, using radio resources having a timing determined in step 340 to synchronize an uplink timing sync with the target cell. do. Since the preamble is previously promised between the terminal 301 and the target cell 305, the eNB controlling the target cell 305 may calculate a timing difference between the terminal and the eNB through reception of the preamble. The eNB informs the terminal of the calculated timing difference (TA) information in step 350, and the terminal receiving the timing difference information corrects the uplink timing using the terminal, and in step 360 the handover to the target cell is performed. Sends a Handover Confirm message to indicate completion. The UL radio resource for handover confirmation allocation information for transmitting the handover complete message is transmitted to the terminal together with uplink timing difference information in step 350. After transmitting the handover complete message, the terminal 301 transmits and receives data with the destination cell 305 in step 370.

As described above, when the handover requires the uplink timing procedure for the target cell, when the uplink timing difference information is transmitted to the terminal, the terminal includes the resource allocation information for transmitting the handover complete message to the target cell. After successfully receiving the over command message and correcting the uplink timing, the handover complete message can be sent immediately.

However, if the handover does not require an uplink timing procedure for the target cell, it is not known when the eNB controlling the target cell should allocate a radio resource for transmitting the handover complete message to the terminal. This is because control information such as a preamble is not received from the terminal.

In order to overcome this, the eNB of the target cell may reserve radio resources for handover completion message transmission in advance with sufficient margin, but this increases the interruption time that occurs during handover. It becomes a factor. On the other hand, when the eNB of the target cell reserves a plurality of radio resources for handover complete message transmission in order to reduce the interruption time, since the radio resources for handover complete message transmission are not small enough to be ignored, If not used, there is a problem that resources are wasted.

Accordingly, the present invention minimizes radio resources reserved by the target cell for handover completion message transmission during handover when uplink timing procedures are not required for the target cell, and at the same time, handover interruption time that occurs during handover. Another embodiment that reduces the number is proposed.

To this end, the present invention uses scheduling request / channel quality information / sound transmission resources, which are radio channel information reconfigured for use in the target cell, rather than allocating a separate radio resource for transmitting a handover complete message to the terminal in the target cell. The terminal requests allocation of radio resources for transmitting the handover complete message. The scheduling request / channel quality information / sounding transmission resource is much smaller than the handover complete message transmission resource, so that the scheduling request / channel quality information / sounding transmission resource is reduced in order to reduce the handover interruption time. Even if you book a dog, you don't waste a lot of radio resources.

However, the scheduling request / channel quality information / sounding transmission resource may not be used for the purpose of requesting to allocate a radio resource for handover completion message transmission, which is the scheduling request / channel quality information / sounding transmission. This is because the resources are infrequent and insufficient to reduce the handover interruption time. Therefore, the network node of the present invention divides the scheduling request / channel quality information / sounding transmission resource information into two steps and includes them in the handover command message instructing handover.

The scheduling request / channel quality information / sounding transmission resource of the first step receives a radio resource for transmitting a handover confirmation message to the destination cell after the terminal successfully receives a handover command message from the source cell. Used during the interval considering the maximum number of HARQ transmissions of time or handover command message, and the scheduling request / channel quality information / sounding transmission resource of the second step is allocated a radio resource for handover completion message transmission from the destination cell. Used.

The scheduling request / channel quality information / sounding transmission of the first step plays a role of requesting resource allocation to transmit a handover complete message after the terminal has successfully received a handover command message. In order to reduce the time, the resource may be allocated more frequently than the scheduling request / channel quality information / sound transmission resource of the second step.

In another embodiment, the scheduling request / channel quality information / sound transmission resource of the first step is used until the terminal successfully transmits the handover complete message to the target cell after successfully receiving the handover command message from the source cell. After that, the scheduling request / channel quality information / sounding transmission resource of the second step may be used.

When the terminal successfully receives the handover command from the source cell, the terminal transmits the corresponding control information using the scheduling request / channel quality information / sound transmission resource of the first step, and the network node transmits the corresponding control information to the scheduling request / channel quality information of the first step. When the control information transmitted from the terminal is detected through the sound transmitter, the terminal allocates a resource for transmitting the handover completion to the target cell, and the terminal is allocated the resource to request the scheduling request / channel quality information / The control information is transmitted using a sounding transmission resource, and a handover complete message is transmitted using a resource allocated to transmit the handover completion.

Next, a second embodiment of the present invention as described above will be described in detail with reference to the accompanying drawings.

4 is a signal flowchart illustrating a handover method when an uplink timing sync procedure is not required for a target cell according to another embodiment of the present invention.

Here, for convenience of description, a handover that does not require an uplink timing sync procedure for a target cell will be referred to as an uplink timing synchronized handover. This uplink timing-synced handover is generally a cell whose size is small enough for the target cell, even if the eNB controlling the source cell and the target cell is the same eNB or the eNB controlling the target cell is different from the eNB controlling the source cell. Therefore, this is applied when the uplink timing sync procedure is unnecessary.

Referring to FIG. 4, the terminal 401 reports a channel state measurement to the source cell 403 in step 410. The channel state measurement report is to measure the channel state of the current cell and the neighbor cell according to a specific event or period set by the eNB of the source cell, and inform the eNB of the result. It is determined whether or not the handover 401).

Although not shown in FIG. 4, when the source cell 403 determines the handover in step 420, the eNB of the source cell 403 exchanges information with the eNB of the destination cell 405. Resource information and the like of a radio channel for use by the terminal 401 are reconfigured by the eNB of the destination cell 405 and signaled to the eNB of the source cell 403. At this time, the eNB of the target cell 405 divides the scheduling request / channel quality information / sounding transmission resource information to be used by the terminal 401 in the target cell 405 in two steps, and the related parameters are source cell 403. Signal to the eNB). The scheduling request / channel quality information / sounding transmission resource of the first step is performed after the terminal 401 successfully receives the handover command message from the source cell 403, and then handovers to the destination cell 405 (Handover Confirm). The radio resource for the message transmission is used or during the interval considering the maximum number of HARQ transmissions of the handover command message, and the scheduling request / channel quality information / sound transmission resource of the second step is handovered from the destination cell 405. This is to use from the time when the radio resource for the completion message is allocated.

The scheduling request / channel quality information / sounding transmission resource of the first step is used by the terminal 401 for the purpose of requesting resource allocation to send the handover complete message successfully after the terminal 401 successfully receives the handover command message. In order to reduce the interruption time, the resource may be allocated more frequently than the scheduling request / channel quality information / sound transmission resource of the second step. If a scheduling request / channel quality information / sound transmission resource reconfigured for the service of the terminal 401 in the target cell 405 is sufficiently frequent, for example, the scheduling request / channel quality information / sounding sender source every 5 ms. If there is no problem in reducing the handover interruption time as in the case of reconfiguring, the scheduling request / channel quality information / sound is reconfigured without having to allocate and allocate two steps of scheduling request / channel quality information / sounding transmission resource. The ding transmission resource may be continuously used from the time of receiving a handover command without step division. However, an example of a case where the two-step scheduling request / channel quality information / sounding transmission resource is divided and allocated will be described.

The eNB of the source cell 403 transmits a handover command message including radio channel reconfiguration information received from the eNB of the target cell 405 to the terminal 401 in step 430, and transmits the target cell to the terminal 401. Instructing to hand over to 405). At this time, the handover command message may include the following information.

A) No need of UL timing sync: Signals that the handover does not require uplink timing sync procedure for the destination cell.

B) Radio channel reconfiguration info: terminal ID, channel & resource information, etc. to be used in the target cell

Two-step scheduling request / channel quality information / sounding transmission resource may be signaled to the radio channel reconfiguration information as follows. In FIG. 4, the first embodiment of signaling is illustrated as an example, but this is only an embodiment and it is understood that the signaling method of the present invention is not limited.

<Signaling Embodiment 1>

A) first step scheduling request / channel quality information / sound transmission resource information

Radio resource information: scrambling code information and channel information allocated to the terminal

Transmission timing information: offset relative to HARQ transmission, can be expressed as the number of subframes

B) second step scheduling request / channel quality information / sound transmission resource information

Radio resource information: It can be omitted if it is same as the radio resource information of the first step.

Transmission timing information: start timing-resource allocation for handover completion message transmission L1 / L2 control information Offset relative to transmission can be represented by the number of subframes, can be represented by the number of subframes in the transmission cycle.

<Seconding Embodiment 2>

First step scheduling request / channel quality information / sounding transmission resource information

Radio resource information: same as in the first embodiment

Transmission Timing Information: Start Timing-Radio Frame Number (RFN) and / or Radio Sub-Frame Number (RSFN), which can be represented by the number of subframes in the transmission cycle, first step scheduling request / Channel Quality Information / Sounding Transmission Resource Coverage-Radio Frame Number and Radio Subframe Number (or can be expressed as the number of subframes)

2nd step scheduling request / channel quality information / sounding transmission resource information

Radio resource information: same as in the first embodiment

Transmission timing information: start timing-radio frame number and radio subframe number, transmission cycle

Referring back to FIG. 4, in step 430 and 440, the source cell 403 transmits each HARQ (Hybrid Automatic Repeat reQuest) transmission of the handover command message to the terminal 401. Step 430 is a first HARQ transmission of the handover command message, step 440 is a second HARQ transmission of the handover command message. In FIG. 4, it is assumed that the terminal has successfully received the handover command message in the second HARQ reception without generating a CRC error, and only the second HARQ transmission is shown. However, the preset maximum until the terminal successfully receives the handover command message is shown. The handover command message may be transmitted as many times as the number of HARQ transmissions.

In steps 430 and 440, the first step scheduling request / channel quality information transmission resource included in the handover command is indicated, and is reserved at the timing after offset relative to each HARQ transmission, which is the number of lion subframes. In FIG. 4, since the terminal does not successfully receive the handover command message in step 430, which is the first HARQ transmission, the scheduling request / channel quality information / sound transmission resource of step 435 reserved after the offset compared to the first HARQ transmission is used. Not doing so wastes resources. In the second HARQ transmission of the handover command message in step 440, if the terminal 401 successfully receives the message, it knows information about the two-step scheduling request / channel quality information / sound transmission resource and step 445. In the first step scheduling request / channel quality information / sounding transmission resource information, the control information is transmitted using the radio resources allocated at the timing after the offset compared to the second HARQ transmission. When the eNB of the target cell 405 monitors the scheduling request / channel quality information / sounding transmission resource of the first step and receives the corresponding control information from the terminal in step 445, the eNB performs handover completion message transmission in step 450. Allocates a radio resource for the L1 / L2 downlink control channel. In this case, the MCS level for the handover complete message may be set based on the channel quality information / sounding transmitted by the terminal in step 445. If the terminal 401 is allocated a radio resource for handover complete message transmission through the L1 / L2 downlink control channel in step 450, the handover is completed by the second step scheduling request / channel quality information / sound transmission resource information. Resource allocation for message transmission After offset relative to the transmission of the L1 / L2 control information, the control information is transmitted using the radio resource allocated to the timing in step 470. Thereafter, in step 490, the corresponding control information is transmitted every second step of the scheduling request / channel quality information / sound transmission cycle represented by the number of subframes. The scheduling request / channel quality information / sounding of the first step may be reserved after an offset timing with respect to each HARQ transmission by the maximum number of HARQ transmissions.

5 is a signal flowchart illustrating the operation of an eNB according to an embodiment of the present invention. Herein, the operation in the case where the eNBs managing the target cell and the source cell are different from each other is described. However, the present invention also includes the case where the target cell and the source cell are each managed by the same eNB.

Referring to FIG. 5, if the eNB of the source cell determines that a handover requiring no uplink timing sync procedure is required for the target cell in step 510, the scheduling request to be reconfigured for service of the terminal in the target cell in step 520. Check if the allocation cycle of channel quality information / sound transmission resources is frequent enough to reduce handover interruption. That is, it is checked whether the allocation cycle is below a predetermined threshold that can sufficiently reduce handover interruption. If it is determined in step 520 that the handover interruption is not a problem, the eNB of the source cell includes the reconfigured scheduling request / channel quality information / sounding transmission resource in the handover command message in step 540. send. However, if it is determined that the handover interruption is a problem as a result of the determination in step 520, the Enb of the source cell configures the 2-step scheduling request / channel quality information / sounding transmission resource information in step 530 and then proceeds to step 540. In step 2, the 2 step scheduling request / channel quality information transmission resource information is included in the handover command message and transmitted. In step 550, the eNB of the target cell monitors the scheduling request / channel quality information / sound transmission resource of the first step and checks whether corresponding control information is received from the terminal. As a result of the check in step 550, when the corresponding control information is received from the terminal through the scheduling request / channel quality information transmission resource of the first step, the eNB of the target cell allocates a radio resource for transmitting a handover complete message to the terminal in step 560. Assign. In step 570, the eNB of the target cell applies the second step scheduling request / channel quality information / sound transmission resource and checks whether corresponding control information is transmitted from the terminal. If the second step scheduling request / channel quality information / sounding transmission resource is applied, the remaining scheduling request transmission resource of the first step reserved for the maximum HARQ transmission number of the handover command message can be released. In another embodiment, even if the second step scheduling request / channel quality information / sounding transmission resource is applied, the remaining scheduling request transmission resource of the first step reserved for the maximum number of HARQ transmissions of the handover command message may be left as it is.

6 is a flowchart illustrating an operation of a terminal according to an embodiment of the present invention.

Referring to FIG. 6, if the terminal successfully receives the handover command message in step 610, the terminal checks whether the handover requires an uplink timing sync procedure for the target cell in step 620. For example, if "No need of UL timing sync" information is set in the handover command message, it is regarded as a handover requiring no uplink timing sync procedure for the target cell. In step 620, if the handover does not require an uplink timing sink procedure for the target cell, the terminal includes two-step scheduling request / channel quality information / sounding transmission resource information in the handover command message in step 630. Check if there is. If it is determined in step 630 that the two-step scheduling request / channel quality information / sounding transmission resource information is included, in step 640, the terminal controls corresponding information using the scheduling request / channel quality information / sounding transmission resource information of the first step. Send the information. If, after receiving the L1 / L2 downlink control information for allocating a radio resource for the handover complete message transmission, in step 650, the terminal releases the scheduling request / channel quality information / sounding transmission resources of the first step and the second The control information is transmitted using the scheduling request / channel quality information / sound transmission resource of the step.

On the other hand, if the check result of step 620 indicates that the handover requires the uplink timing sync procedure for the target cell, the terminal performs the uplink timing sync procedure in step 660. If the check result of step 630 does not include two-step scheduling request / channel quality information / sounding transmission resource information, the terminal determines the scheduling request / channel quality information / sounding resource as instructed without step division in step 670. Transmit the corresponding control information.

7 is a block diagram illustrating an internal configuration of an eNB according to an embodiment of the present invention.

Referring to FIG. 7, the channel state report manager 710 manages basic information for determining handover. The handover determiner 720 determines whether the terminal is handed over using the information received from the channel state report manager 710. Upon receipt of the handover decision signal determined from the handover decision unit 720, the L2 / L3 message generator 730 generates a handover command, and the scheduling request / channel quality information / sound reconstructed in the target cell. The two-step scheduling request / channel quality information / sounding transmission resource information may be configured according to the frequency of the transmission resource, and the information is included in the handover command and output. Then, the transceiver 750 transmits the handover command to the terminal. Meanwhile, the SR / CQI / Sounding resource control / management unit 740 controls and manages the scheduling request / channel quality information / sounding transmission resource. The scheduling request / channel quality information / sounding transmission resource in the destination cell reserved by the SR / CQI / Sounding resource control / management unit 740 is reflected to the scheduler 760 so that the same resource is not used for other purposes. If the scheduling request / channel quality information / sounding received through the transmitter / receiver 750 uses the scheduling request / channel quality information / sounding transmission resource of the first step, the scheduler 760 may transmit a radio for handover completion message to the terminal. After allocating the resources, the transceiver 750 receives the corresponding control information from the terminal through the scheduling request / channel quality information / sounding transmission resource of the second step.

8 is a block diagram illustrating a configuration of a terminal according to an embodiment of the present invention.

Referring to FIG. 8, the transceiver 800 receives and outputs a handover command message from an eNB. The L2 / L3 message analyzing unit 810 receives and interprets a handover command message from the transceiver 800, and then detects scheduling request / channel quality information / sounding transmission resource information in a target cell, and performs SR / Output to the CQI / Sounding resource management unit 820. Then, the SR / CQI / Sounding resource manager 820 manages this. When the transceiver 800 receives the 2-step scheduling request / channel quality information / sounding transmission resource information, the SR / CQI / Sounding generation unit according to the scheduling request / channel quality information / sounding transmission resource information of the first step. The control information is generated at 830 and transmitted and received to the eNB through the transceiver 800 using the corresponding radio resource at a corresponding timing. If, as a result, when receiving the L1 / L2 downlink control information indicating the radio resource allocation for handover complete message transmission through the transceiver 810, after this point SR / CQI / Sounding resource management unit 820 By canceling the scheduling request / channel quality information / sounding transmission resources of the first step by using the scheduling request / channel quality information / sounding transmission resources of the second step and transmits the corresponding control information through the transceiver 810.

As described above, the present invention occurs at the time of handover while minimizing radio resources reserved in the target cell for handover completion message transmission in two steps during handover when uplink timing procedure is not required for the target cell. This reduces the handover interruption time.

Claims (36)

A handover method by a base station for servicing an uplink timing synchronized terminal for a target cell in a mobile communication system, Determining, by the base station of the source cell, whether an allocation cycle of reconfiguration scheduling request / channel quality information / sound transmission resource for the terminal is greater than a predetermined threshold; If the allocation cycle of the source cell is larger than the predetermined threshold, the base cell configures the two-stage scheduling request / channel quality / sounding information transmission resource information and then hands over the two-stage scheduling request / channel quality information / sounding transmission resource information. Including the command message and transmitting it to the terminal; When the base station of the target cell receives the corresponding control information from the terminal through the scheduling request / channel quality information / sounding transmission resources of the first step, allocating a radio resource for transmitting a handover complete message to the terminal; Handover method by the base station characterized in that configured. The method of claim 1, When the base station of the target cell receives the corresponding control information from the terminal through the second stage scheduling request / channel quality information / sound transmission resource, the remaining scheduling of the first stage, which is reserved for the maximum number of HARQ transmissions of the handover command message, is scheduled. And handing off the request transmission resource. A method for handover of an uplink timing-synchronized terminal to a target cell in a mobile communication system, Checking whether the handover command message includes two-stage scheduling request / channel quality information / sounding transmission resource information according to a successful reception of the handover command message; Transmitting the control information using the scheduling request / channel quality information / sounding transmission resource information of the first step if the scheduling request / channel quality information / sounding transmission resource information is included; Upon receiving control information for allocating a radio resource for handover completion message transmission, the scheduling request / channel quality information / sound transmission resource of the first step is released and the scheduling request / channel quality information / sound of the second step is released. Handover method of a terminal comprising the step of transmitting the control information by using the transmission resource. A base station apparatus supporting handover of an uplink timing-synchronized terminal for a target cell in a mobile communication system, A channel status reporting manager for managing basic information for determining handover; A handover determination unit which determines whether a terminal is handed over using the information received from the channel state report management unit; According to the handover decision signal output from the handover decision unit, a two-stage scheduling request / channel is generated according to the frequency of the scheduling request / channel quality information / sounding transmission resource reconstructed in the target cell while regenerating a handover command. A message management unit configured to output quality information / sounding transmission resource information and include the same in a handover command message; And a transceiver for converting and outputting a handover command message output from the message manager into a wireless signal for transmission to a terminal. delete A terminal apparatus performing handover in an uplink timing synchronized state with respect to a target cell in a mobile communication system, A transceiver for converting and outputting a handover command message received as a radio signal from a base station; A message analysis unit for receiving and analyzing a handover command message from the transceiver, and detecting and outputting scheduling request / channel quality information / sounding transmission resource information in a target cell; When receiving the two-stage scheduling request / channel quality information / sounding transmission resource information from the transmission and reception unit, according to the scheduling request / channel quality information / sounding transmission resource information of the first step, generating the corresponding control information to the transceiver SR / CQI / Sounding generation unit for outputting, Managing the information output from the message analysis unit, when receiving the L1 / L2 downlink control information indicating the radio resource allocation for handover complete message transmission through the transceiver, the first step scheduling request / channel quality information And a SR / CQI / Sounding resource management unit for releasing sounding transmission resources and transmitting corresponding control information through a transmission / reception unit using the scheduling request / channel quality information / sounding transmission resources of the second step. Device. A handover method performed in a base station supporting handover of a terminal moving from a source cell to a target cell in a wireless communication system, Allocating transmission resources of a scheduling request / channel quality information (SR / CQI) periodically transmitted by the terminal to the target cell; Checking whether control information has been received from the terminal through the transmission resource of the allocated SR / CQI; And allocating a radio resource for transmitting a handover complete message by the terminal when the control information is received from the terminal. The method of claim 7, wherein Wherein the handover is performed at a base station that is a handover for which no uplink timing sync procedure is required for the destination cell. The method of claim 7, wherein The transmission resource information of the SR / CQI is performed in the base station included in the handover command message transmitted to the terminal. The method of claim 9, The handover command message is performed in a base station transmitted to the terminal within a maximum number of hybrid automatic repeat-request (HARQ) transmission times. The method of claim 9, The transmission resource information of the SR / CQI is performed in a base station including radio resource information allocated to the terminal and transmission timing information in which the terminal transmits the control information to the base station. The method of claim 7, wherein Allocating the transmission resource of the SR / CQI, Checking whether an allocation cycle of the transmission resource of the SR / CQI is smaller than a predetermined threshold; And adjusting the allocation cycle of the transmission resource of the SR / CQI when the allocation cycle of the transmission resource of the SR / CQI is greater than the threshold. The method of claim 12, Adjusting the allocation cycle of the transmission resource of the SR / CQI, Reconstructing the transmission resource information of the SR / CQI into a plurality of steps according to the allocation cycle, wherein at least one of the reconstructed transmission resource information of the SR / CQI is an allocation cycle of the transmission resource of the SR / CQI Handover method performed at a base station set to be greater than the threshold. The method of claim 12, The threshold is performed in the base station is set in consideration of the interruption time generated during the handover. The method of claim 13, Transmission resource information of the reconstructed SR / CQI is included in a handover command message transmitted to the terminal, and transmission resource information of the first step of the transmission resource information of the reconstructed SR / CQI is transmitted from the source cell. A handover method performed at a base station used for requesting allocation of a resource to transmit the handover complete message to the destination cell after successfully receiving a handover command message. The method of claim 15, The handover command message is transmitted to the terminal within a maximum number of hybrid automatic repeat-request (HARQ) transmission times, and the HARQ transmission number after receiving the control information according to the transmission resource information of the first step from the terminal. And if there is an unused transmission resource of the first step within a range, deallocating the unused transmission resource. A base station supporting handover of a terminal moving from a source cell to a target cell in a wireless communication system, A transceiver for transmitting and receiving data wirelessly with the terminal; A message generator for generating transmission resource information of a scheduling request / channel quality information (SR / CQI) periodically transmitted by the terminal to the target cell; A scheduler for allocating a transmission resource of the SR / CQI and a radio resource for transmitting a handover complete message by the terminal; The message generator and the scheduler are allocated such that the radio resource is allocated to the terminal when the transmission resource of the SR / CQI is allocated to the terminal and control information is received from the terminal through the allocated SR / CQI transmission resource. And a controller configured to control the overall operation of the message generator. The method of claim 17, And the handover is a handover for which no uplink timing sync procedure is required for the destination cell. The method of claim 17, The base station, the transmission resource information of the SR / CQI is included in the handover command message transmitted to the terminal. The method of claim 19, The handover command message is a base station transmitted to the terminal within the maximum number of hybrid automatic repeat-request (HARQ) transmission number. The method of claim 19, The transmission resource information of the SR / CQI includes radio resource information allocated to the terminal and transmission timing information of the terminal transmitting the control information to the base station. The method of claim 17, The control unit determines whether the allocation cycle of the transmission resource of the SR / CQI is smaller than a predetermined threshold when allocating the transmission resource of the SR / CQI, and if the allocation cycle of the transmission resource of the SR / CQI is larger than the threshold A base station further configured to adjust the allocation cycle of transmission resources of SR / CQI. The method of claim 22, The control unit is further configured to reconfigure the transmission resource information of the SR / CQI in a plurality of steps according to the allocation cycle when adjusting the allocation cycle of the transmission resource of the SR / CQI, the transmission resource of the reconstructed SR / CQI At least one of the information is configured such that an allocation cycle of the transmission resource of the SR / CQI is greater than the threshold. The method of claim 22, The controller is configured to set the threshold in consideration of the interruption time generated during the handover. The method of claim 23, Transmission resource information of the reconstructed SR / CQI is included in a handover command message transmitted to the terminal, and transmission resource information of the first step of the transmission resource information of the reconstructed SR / CQI is transmitted from the source cell. And a base station used for requesting allocation of resources to transmit the handover complete message to the destination cell after successfully receiving a handover command message. The method of claim 25, The handover command message is transmitted to the terminal within a maximum number of hybrid automatic repeat-request (HARQ) transmissions, and the control unit receives the control information according to the transmission resource information of the first step from the terminal. The base station further configured to deallocate the unused transmission resources when there is an unused transmission resource of the first step within a range of HARQ transmission times. A handover method performed in a terminal moving from a source cell to a target cell in a wireless communication system, Receiving, from the base station of the source cell at all times, a message including transmission resource information of scheduling request / channel quality information (SR / CQI) periodically transmitted to the base station of the target cell; Transmitting control information to a base station of the target cell according to the transmission resource information of the SR / CQI; And a radio resource for allocating a handover complete message from the base station of the target cell receiving the control information. The method of claim 27, The handover is performed at a terminal that is a handover for which no uplink timing sync procedure is required for the destination cell. The method of claim 27, The message including the transmission resource information of the SR / CQI is a handover command message received from the base station of the base station of the source cell, the handover command message is transmitted within the maximum number of hybrid automatic repeat-request (HARQ) transmission number Handover method performed in the terminal. The method of claim 27, The transmission resource information of the SR / CQI is reconstructed in a plurality of steps through the base station of the target cell according to the allocation cycle, and at least one of the reconstruction resource information of the reconstructed SR / CQI is determined by the transmission resource of the SR / CQI. An allocation cycle is set to be larger than a predetermined threshold, wherein the threshold is performed in the terminal in consideration of the interruption time generated during the handover. The method of claim 27, Determining whether the transmission resource information of the SR / CQI comprises a plurality of steps after receiving the transmission resource information of the SR / CQI; When the transmission resource information of the SR / CQI consists of the plurality of steps, the base station of the target cell allocates the radio resource for transmitting the handover complete message using the transmission resource information of the SR / CQI of the first step. Handover method performed in the terminal comprising the process of requesting. A terminal for performing handover in a wireless communication system, A transceiver for transmitting and receiving data to and from the base station wirelessly; A message analyzing unit for analyzing transmission resource information of scheduling request / channel quality information (SR / CQI) periodically transmitted to the base station; A control information generator for generating control information transmitted to the base station according to the transmission resource information of the SR / CQI; After receiving the analysis result of the transmission resource information of the SR / CQI from the message analysis unit and controls the transceiver to transmit the control information generated by the control information generation unit to the base station according to the analysis result, the control And a resource management unit for allocating a radio resource for transmitting a handover complete message from the base station receiving the information. The method of claim 32, The handover is a handover in which no uplink timing sync procedure is required for a destination cell. The method of claim 32, The message including the transmission resource information of the SR / CQI is a handover command message received from the base station, the handover command message is transmitted within a maximum number of hybrid automatic repeat-request (HARQ) transmission number. The method of claim 32, The transmission resource information of the SR / CQI is reconfigured in a plurality of steps through the base station according to the allocation cycle, and at least one of the reconstruction resource information of the SR / CQI is allocated to the allocation cycle of the transmission resource of the SR / CQI. The terminal is set to be larger than a predetermined threshold, and the threshold is set in consideration of the interruption time generated during the handover. In a wireless communication system that supports handover, Generates transmission resource information of scheduling request / channel quality information (SR / CQI), allocates transmission resources of the SR / CQI, and performs predetermined control through transmission resources of the assigned SR / CQI. A base station for allocating radio resources for transmission of a handover complete message when information is received; When the message including the transmission resource information of the SR / CQI is received, control information is generated and transmitted from the base station according to the transmission resource information of the SR / CQI, and a handover completion message is received from the base station receiving the control information. A wireless communication system supporting a handover comprising a terminal assigned a radio resource for transmission.

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