WO2014038754A1

WO2014038754A1 - Terminal, method for estimating uplink channel, and communication system

Info

Publication number: WO2014038754A1
Application number: PCT/KR2012/011049
Authority: WO
Inventors: 박규진; 이경준
Original assignee: 주식회사 케이티
Priority date: 2012-09-10
Filing date: 2012-12-18
Publication date: 2014-03-13
Also published as: KR20140033773A; KR101472101B1

Abstract

Provided are a terminal, a method for estimating an uplink channel, and a communication system. The terminal comprises: an uplink channel management unit for generating a physical random access channel preamble according to random access channel resource configuration information, which is allocated by a serving base station; and a communication unit for transmitting the physical random access channel preamble to a neighboring base station according to a request by the uplink channel management unit, wherein the physical random access channel preamble is used by the neighboring base station to estimate the uplink channel.

Description

UE, UL channel estimation method and communication system

The present invention relates to a terminal, an uplink channel estimation method, and a communication system.

Due to the introduction of machine type communication (MTC) and the spread of smart phones, the number of terminals requiring wireless connection is increasing rapidly. As a result, the demand for supporting a high data rate for each terminal is also rapidly increasing. In this environment, wireless operators divide the base station into digital units (DUs) and radio units (RUs) to efficiently manage allocated radio resources and support high data rates. Is trying to maximize.

In addition, heterogeneous network (Het-Net) scenarios in which cell sizes covered by respective RUs vary due to transmission power imbalance between RUs are becoming common.

Independent heterogeneous communication schemes between RUs to guarantee high data rates even for UEs located in cell boundary areas in heterogeneous networks and independent uplink / downlink path establishment due to coverage imbalance between uplink and downlink (i.e. An RU as a transmission point (TP) for transmitting a downlink signal and an RU as a reception point (RP) for receiving an uplink signal from a corresponding terminal are independently set).

However, in order to apply such an evolved cooperative communication method, not only an uplink channel measurement in a serving base station connected with any one terminal but also an uplink channel measurement method with a corresponding base station is required.

In particular, in a CoMP scenario, a cooperative communication technique between adjacent base stations has been proposed as a method for increasing uplink and downlink data rates of a terminal located in a cell boundary region. In this case, a terminal located in a cell boundary area requires an uplink channel estimation method with a neighbor base station for cooperative communication.

In the current 3GPP LTE / LTE-A system, a random UE performs a sounding reference signal for periodically or aperiodically measuring an uplink channel state for uplink channel estimation with a base station of a cell to which it is connected. , SRS). In general, in the case of a sounding reference signal (SRS) for uplink channel state measurement, the terminal is transmitted from the terminal to the serving base station by RRC parameters set from the serving base station to which the corresponding terminal belongs. Such RRC parameters include cell-specific SRS subframe and SRS bandwidth, UE-specific SRS bandwidth, hopping patter, frequency domain position, periodicity, subframe configuration, antenna configuration, base sequence index, and cyclic shift index. The terminal transmits a sounding reference signal (SRS) according to the UE-specific parameter in an uplink subframe / bandwidth region that satisfies the cell-specific parameter.

Therefore, a method of enabling uplink channel measurement between a corresponding terminal and a neighboring cell by receiving a sounding reference signal (SRS) transmission of a terminal located in a cell boundary region not only from the serving base station but also from the neighboring base station has been proposed. That is, as the necessity of measuring an uplink channel with a multi-base station for cooperative communication has emerged, a scheme for sharing the sounding reference signal (SRS) configuration information with a neighboring base station and receiving the neighboring base station has been proposed.

However, since a conventional sounding reference signal (SRS) is generated based on a physical cell ID of a base station to which a terminal belongs, a neighboring base station having a different physical cell identifier is a sounding reference signal (SRS) signal generated by a serving base station. It is impossible to receive it. In addition, when a cell size between neighboring cells is different in a heterogeneous network, it is also opaque whether an uplink signal of a terminal having a TA value set based on a reception timing of a serving base station is received in synchronization with a neighboring base station.

As such, since the sounding reference signal (SRS) configuration information is determined by a parameter of the serving base station, even if the sounding reference signal (SRS) configuration information is shared with the neighboring base station, if the neighboring base station receives the sounding reference signal (SRS), At least two additional conditions must be met.

1) Use same cell ID between serving cell and neighbor cell (CoMP scenario 4)

2) The same uplink synchronization can be applied between a serving cell and an adjacent cell in a cell boundary region.

As such, the conventional sounding reference signal (SRS) transmission scheme considering only uplink channel estimation with a single base station is sufficient uplink to support various cooperative communication schemes in a CoMP scenario and a heterogeneous network (HetNet). It does not provide channel estimation results. In addition, the uplink channel estimation technique with a plurality of base stations limited to a limited scenario has a narrower application range, and thus, a design of a plurality of uplink channel estimation techniques applicable to various cell deployment scenarios is required. It is true.

An object of the present invention is to provide a terminal, an uplink channel estimation method, and a communication system for estimating a multi-uplink channel between a terminal and a plurality of base stations based on a random access channel (RACH).

According to an aspect of the present invention, a terminal includes: an uplink channel manager for generating a physical random access channel preamble according to random access channel resource configuration information allocated from a serving base station; And a communication unit configured to transmit the physical random access channel preamble to an adjacent base station according to a request of the uplink channel manager.

The physical random access channel preamble is used by the neighbor base station to estimate an uplink channel.

At this time, the communication unit,

Transmit the physical random access channel preamble to a serving base station according to a request of the uplink channel manager;

The physical random access channel preamble may be used by the serving base station to estimate an uplink channel.

In addition, the uplink channel manager,

The communication unit may request the physical random access channel preamble to be transmitted a plurality of times periodically or aperiodically.

In addition, the uplink channel manager,

The allocated random access channel resource configuration information may be obtained from a physical downlink control channel command received according to a random access procedure instruction from the serving base station.

In addition, the allocated random access channel resource configuration information,

A preamble index, a physical random access channel resource index, and a physical random access channel mask index,

The uplink channel manager,

The physical random access channel preamble generated using the preamble index is set through a preamble index information region of a physical downlink control channel command according to physical random access channel configuration information, and the physical random access channel mask index is set. Through the physical random access channel resource index set through the adjacent base station can be transmitted.

In addition, the uplink channel manager,

The physical random access channel configuration information may be received through cell specific system information of the serving base station.

In addition, the uplink channel manager,

The allocated random access channel resource configuration information may be obtained from a mobility control information region of a radio resource control connection reconfiguration message received according to a fake handover indication from the serving base station.

In addition, the radio resource control connection reconfiguration message,

System information of the neighboring base station and the allocated random access channel resource setting information;

The allocated random access channel resource configuration information,

The preamble index, the preamble mask index, timer information, and preamble transmission maximum information may be included.

When the radio resource control access reconfiguration message including the allocated random access channel resource configuration information is received, the terminal requests the uplink channel manager to generate and transmit the physical random access channel preamble and the timer. When the timer according to the information expires, it may further include a handover controller for performing network re-entry through the optimization cell selection.

When the radio resource control access reconfiguration message including the allocated random access channel resource configuration information is received, the terminal requests the uplink channel manager to generate and transmit the physical random access channel preamble, and the physical If the number of times of random access channel preamble transmission satisfies the information on the maximum number of preamble transmissions, the apparatus may further include a handover controller for performing network re-entry by selecting an optimized cell.

In addition, the uplink channel manager,

A radio resource control signaling (RRC signaling) message including the allocated random access channel resource configuration information may be received from the serving base station.

In addition, the uplink channel manager,

The physical random access channel preamble may be transmitted to the neighbor base station through the resource region of the physical uplink shared channel of the neighbor base station.

In addition, the uplink channel manager,

The physical random access channel preamble may be transmitted to the neighbor base station through a physical random access channel opportunity (PRACH opportunity) of the neighbor base station.

In addition, the terminal periodically or aperiodically transmits a result of estimating a downlink channel with the serving base station to the serving base station, and if the result of estimating the downlink channel satisfies a predetermined threshold condition, the The apparatus may further include a downlink channel manager for transmitting a result of estimating a downlink channel with a neighbor base station to the neighbor base station.

According to another aspect of the present invention, a method for estimating an uplink channel is a method for estimating an uplink channel by a base station control apparatus that controls and manages a plurality of base stations, which is allocated by a serving base station connected to the terminal from a base station adjacent to the terminal. Receiving an uplink channel estimation result between the terminal and the neighbor base station using a random access channel preamble; And performing multi-uplink channel estimation for inter-cell cooperative communication using an uplink channel estimation result between the terminal and the adjacent base station.

In this case, the uplink channel estimation method further includes receiving an uplink channel estimation result between the mobile station and the serving base station using the random access channel preamble from the serving base station,

Performing the multi-uplink channel estimation,

The method may include performing multi-uplink channel estimation between the terminal and a plurality of base stations based on uplink channel estimation results received from each of the serving base station and the adjacent base station.

In addition, performing the multi-uplink channel estimation may include:

The method may include determining whether to implement downlink cooperative communication between cells by determining whether the terminal is located in an area requiring downlink cooperative communication between cells.

In addition, performing the multi-uplink channel estimation may include:

The method may include determining whether the terminal is handover.

In addition, performing the multi-uplink channel estimation may include:

The method may include determining whether to implement an uplink rerouting of the terminal for transmitting the uplink to the neighboring base station while maintaining the downlink with the serving base station.

In addition, before the step of receiving an uplink channel estimation result between the terminal and the adjacent base station,

Determining a target terminal requiring the multi-uplink channel estimation; And instructing multi-uplink channel estimation to the serving base station to which the target terminal is connected.

In addition, the determining step,

Receiving a downlink channel estimation result between the terminal and the serving base station from the serving base station; And determining the target terminal based on the downlink channel estimation result.

In addition, the determining step,

Receiving a downlink channel estimation result from the serving base station between the terminal requiring handover and the serving base station; Receiving a downlink channel estimation result between the terminal requiring handover and the neighbor base station from the neighbor base station; And determining the target terminal based on respective downlink channel estimation results between the serving base station and the neighbor base station.

In addition, the determining step,

Receiving a cell interference signal in a specific frequency band from the adjacent base station; And determining, as the target terminal, a terminal scheduled in the specific frequency band where the cell interference signal is generated.

According to still another aspect of the present invention, a communication system includes: a serving base station for allocating a random access channel resource for uplink channel estimation to a terminal located in a cell boundary region; An adjacent base station receiving a physical random access channel preamble generated according to the random access channel resource allocated from the serving base station from the terminal and estimating an uplink channel with the terminal using the physical random access channel preamble ; And a base station control apparatus for receiving a result of estimating an uplink channel with the terminal from the neighbor base station and estimating a multi-uplink channel for cooperative communication between cells.

At this time, the serving base station,

Using the physical random access channel preamble received from the terminal, transmits a result of estimating an uplink channel with the terminal to the base station controller,

The base station control device,

Multi-uplink channel estimation between the terminal and a plurality of base stations may be performed based on uplink channel estimation results received from each of the serving base station and the adjacent base station.

In addition, the serving base station and the adjacent base station,

It may be connected to the same base station control device or different base station control devices.

In addition, the serving base station and the neighboring base station is a radio signal processing device for forming each independent cell, the base station control device is connected to the serving base station and the neighboring base station to perform a base station control management function to the communication station It may include a cloud-based base station structure that is implemented as a virtual server that is centrally installed.

In addition, the serving base station and the adjacent base station,

Each cell included in an inter-cell cooperative communication group for a terminal located in a cell boundary region may be formed.

In addition, a heterogeneous network in which the serving base station and the neighboring base station having different cell coverages may overlap each other may be formed.

In addition, the serving base station and the adjacent base station,

In the macro cell and the macro cell, a plurality of small cells having a smaller cell radius than the macro cell may be formed.

According to an embodiment of the present invention, a physical random access channel sequence (PRACH sequence) is used as a form of a reference signal for measuring an uplink channel state with an adjacent cell as well as an uplink channel with a serving cell to which a terminal is connected. Accordingly, multi-uplink channel estimation that is universally applicable in various heterogeneous networks (Het-Net) and the CompMP scenario is possible.

Therefore, based on the uplink channel estimation result measured by the plurality of base stations, it is possible to provide a basis for determining whether the terminal enters a cooperative communication area (cell boundary area). In addition, an independent path establishment method between uplink and downlink, in particular, may provide a framework capable of providing a result of a base channel estimation for determining whether an uplink path is reset.

1 is a diagram illustrating a network to which an embodiment of the present invention is applied.

2 illustrates a cloud-based base station structure to which an embodiment of the present invention is applied.

3 is a block diagram showing a schematic configuration of a serving base station according to an embodiment of the present invention.

4 is a block diagram showing a schematic configuration of a neighbor base station according to an embodiment of the present invention.

5 is a block diagram showing a schematic configuration of a base station control apparatus according to an embodiment of the present invention.

6 is a block diagram showing a schematic configuration of a terminal according to an embodiment of the present invention.

7 is a flowchart illustrating an uplink channel estimation method according to an embodiment of the present invention.

8 is a flowchart illustrating an uplink channel estimation method according to another embodiment of the present invention.

9 is a flowchart illustrating an uplink channel estimation method according to another embodiment of the present invention.

10 is a flowchart illustrating a method of determining a target terminal according to an embodiment of the present invention.

11 is a flowchart illustrating a method of determining a target terminal according to another embodiment of the present invention.

12 is a flowchart illustrating a method of determining a target terminal according to another embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless specifically stated otherwise.

In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

In the present specification, a terminal is a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a user equipment (User Equipment). It may also refer to a user equipment (UE), an access terminal (AT), and the like, and may include all or some functions of a terminal, a mobile terminal, a subscriber station, a portable subscriber station, a user device, an access terminal, and the like.

In the present specification, a base station (BS) includes an access point (AP), a radio access station (RAS), a node B (Node B), an advanced node B (evolved NodeB, eNodeB), transmission and reception It may also refer to a base transceiver station (BTS), a mobile multihop relay (MMR) -BS, and the like, and may perform all or part of functions of an access point, a wireless access station, a node B, an eNodeB, a transmission / reception base station, an MMR-BS, and the like. It may also include.

In the present invention, not only downlink cooperative communication, but also independent uplink and downlink path setting methods will be referred to as cooperative communication.

Now, a terminal, an uplink channel estimation method, and a communication system according to an embodiment of the present invention will be described with reference to the drawings.

1 is a block diagram of a communication system to which an embodiment of the present invention is applied, FIG. 2 illustrates a cloud-based base station structure to which an embodiment of the present invention is applied, and FIG. 3 is a schematic diagram of a serving base station according to an embodiment of the present invention. 4 is a block diagram showing a schematic configuration of a neighboring base station according to an embodiment of the present invention, Figure 5 is a block diagram showing a schematic configuration of a base station control apparatus according to an embodiment of the present invention 6 is a block diagram showing a schematic configuration of a terminal according to an embodiment of the present invention.

3 to 6 schematically show only the configuration related to the embodiment of the present invention.

First, referring to FIG. 1, in a communication system to which an embodiment of the present invention is applied, a heterogeneous heterogeneous arrangement of a first base station 100 and a second base station 200 having cell coverage of different sizes is arranged. Heterogeneous network (Het-Net). Here, only two base stations are shown, but may include a plurality of base stations.

In such a heterogeneous network, a macro cell 300 serving as a service area of the first base station 100 and a small cell 400 serving as a service area of the second base station 200 overlap each other. The small cell 400 covers a smaller area than the macro cell 300. A plurality of small cells 400 may exist in one macro cell 300. That is, in one macro cell 300, small cells 400 such as pico cells, micro cells, and femto cells are superimposed by distributed low power remote radio heads (RRHs). Appears.

In addition, a communication system to which an embodiment of the present invention is applied is a cooperative multi-point scenario (CoMP scenario, Coordinated Multi-) to increase uplink and downlink data rates of a terminal located in a cell boundary region through cooperative communication between adjacent cells. Point scenario) 3 and 4 may be a cloud-based base station structure, as shown in FIG.

Referring to FIG. 2, in the cloud-based base station structure, a general base station is divided into a digital signal processing unit (DU) and a radio signal processing unit (RU) 900. A typical base station includes a processing unit corresponding to each of the digital signal processing apparatus 800 and the wireless signal processing apparatus 900 in one physical system, and one physical system is installed in a service area. In contrast, according to the cloud-based base station structure, the digital signal processing apparatus 800 and the wireless signal processing apparatus 900 are physically separated, and only the wireless signal processing apparatus 900 is installed in the service target area. In addition, one digital signal processing apparatus 800 has a control management function for the plurality of wireless signal processing apparatuses 900 forming respective independent cells. In this case, the digital signal processing apparatus 800 and the wireless signal processing apparatus 900 may be connected by an optical cable.

Here, the digital signal processing apparatus 800 is a part in charge of the digital signal processing and resource management control function of the base station, and is connected to a core system (not shown). And it is mainly installed in communication companies such as Internet data center (IDC, Internet Data Center). In addition, the digital signal processing apparatus 800 may use various wireless technologies such as wideband code division multiple access (WCDMA), WiBro (WiBro, Wireless Broadband Internet), and LTE (Long Term Evolution) through a virtualization technology. The digital signal processing apparatus 800 may be operated as one by applying the software to the 800.

In addition, the wireless signal processing apparatus 900 is a part for amplifying and radiating a radio wave signal in a wireless signal processing section of a base station to an antenna. That is, the wireless signal processing apparatus 900 converts and amplifies a digital signal received from the digital signal processing apparatus 800 into a radio frequency (RF) signal according to a frequency band.

Referring back to FIG. 1, the first base station 100 and the second base station 200 are implemented with the wireless signal processing apparatus 900 of FIG. 2. And it may be called eNB, RU, RRH (Remote Radio Heads). In addition, the base station control apparatus 500 is implemented with a digital signal processing apparatus 800 of FIG. And it is connected to the first base station 100 and the second base station 200 to manage them.

Here, although the first base station 100 and the second base station 200 are shown to be managed by a single base station control apparatus 500, the first base station 100 and the second base station 200 control the different base stations Each may be managed by the device 500.

According to the cooperative multi-point (CoMP) scenario, the terminal 600 located in the cell boundary region is required to estimate an uplink channel with the neighbor base station 200.

Here, the terminal 600 located in the cell boundary region is defined as a terminal located in the region where the first cell 300 is located but may be affected by the second cell 400. The terminal 600 located in the cell boundary region is not only the first base station 100 currently connected, unlike the terminal 700 located at the center of the second cell 400 transmits and receives only a signal with the second base station 200. A signal may also be transmitted and received with the second base station 200 which is an adjacent base station.

Hereinafter, the first base station 100 will be described as a serving base station, and the second base station 200 will be described as a neighbor base station based on the terminal 600 located in the cell boundary region.

The terminal 600 located in the cell boundary region receives the downlink physical channel and the physical signal from the serving base station 100 (①). Here, the downlink physical channel includes a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), and a physical broadcast channel (PBCH). The physical signal includes a Common Reference Signal (CRS), a Primary Synchronization Signal (PSS) / Secondary Synchronization Signal (SSS), a Channel State Information-Reference Signal (CSI RS), a DeModulation-Reference Signal (DM RS), and the like.

In addition, the terminal 600 located in the cell boundary region according to the uplink channel state between the terminal 600 and the serving base station 100 and the uplink channel state between the terminal 600 and the second base station 200. The channel and physical signals may be set to be transmitted to the serving base station 100 or may be set to be transmitted (②) to the second base station 200. Here, the uplink physical channel includes a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and the physical signal includes a sounding reference signal (SRS).

Here, the terminal 600 located in the cell boundary region receives a dedicated physical random access channel (PRACH) configuration signal from the serving base station 100. The dedicated physical random access channel resource configuration signal includes resource allocation information for UE 600 uplink channel estimation with an adjacent cell. The dedicated physical random access channel resource setting signal is transmitted from the serving base station 100 to a target terminal that is a multi-uplink estimation target according to the instruction of the base station control apparatus 500.

Here, the target terminal refers to a multi-uplink estimation target terminal determined by the base station control apparatus 500, and eventually becomes the terminal 600 located in the cell boundary region. In this case, the multi-uplink channel estimation is defined as uplink channel estimation between the target terminal 600 and two or more base stations.

Meanwhile, the terminal 600 transmits a physical random access channel preamble (PRACH preamble) to the adjacent base station 200 according to the dedicated physical random access channel resource configuration signal. Then, the neighboring base station 200 estimates an uplink channel state with the terminal 600 based on the physical random access channel preamble and reports it to the base station control apparatus 500.

In addition, the terminal 600 transmits a physical random access channel preamble (PRACH preamble) to the serving base station 100 according to the dedicated physical random access channel resource configuration signal. Similarly, the serving base station 100 estimates an uplink channel state with the terminal 600 based on the physical random access channel preamble and reports it to the base station control apparatus 500.

Then, the base station control apparatus 500 performs multi-uplink channel estimation based on each uplink channel state reported from the serving base station 100 and the neighbor base station 200. That is, the terminal 600 estimates the uplink channel with the neighboring base station 200 as well as the uplink channel with the serving base station 100 to which the terminal 600 is currently connected. It may determine whether to implement the downlink cooperative communication between cells. Alternatively, handover of the terminal 600 may be implemented. Alternatively, it may be determined whether the UL 600 implements UL path redirection. Here, the uplink path reset refers to a state in which only the uplink is transmitted to the neighboring base station 200 while maintaining the downlink with the serving base station 100.

Now, a schematic configuration of the serving base station 100, the adjacent base station 200, the base station control apparatus 500 and the terminal 600 will be described.

First, referring to FIG. 3, the serving base station 100 includes a communication unit 110, a memory 130, and a processor 150.

Here, the communication unit 110 is connected to the processor 150, and transmits and receives a radio signal. The communication unit 110 may include a baseband circuit for processing a radio signal. The memory 130 is connected to the processor 150 and stores various information for driving the processor 150. The memory 130 may be implemented as a medium such as a RAM such as a dynamic random access memory, a RAM random dynamic memory (DRAM), a synchronous DRAM, a static RAM, or the like. The memory 130 may be inside or outside the processor 150 and may be connected to the processor 150 by various well-known means.

The processor 150 may be implemented as a central processing unit (CPU), other chipsets, microprocessors, or the like, and layers of the air interface protocol may be implemented by the processor 150. The processor 150 includes an allocator 251, an estimator 253, and a reporter 255.

In this case, the allocator 251 generates a dedicated physical random access channel resource setting signal for allocating a resource for uplink channel estimation between the terminal 600 and the neighbor cell 400 according to the instruction of the base station control apparatus 500. It generates and transmits to the terminal 600.

The estimator 253 receives a physical random access channel preamble according to the dedicated physical random access channel resource configuration signal from the terminal 600 and estimates an uplink channel state with the terminal 600.

The reporter 255 receives the uplink channel estimation result from the estimator 253 and transmits the uplink channel estimation result to the base station control apparatus 500.

Next, referring to FIG. 4, the neighbor base station 200 includes a communication unit 210, a memory 230, and a processor 250.

Here, the communication unit 210 is connected to the processor 250, and transmits and receives a radio signal. The communication unit 210 may include a baseband circuit for processing a radio signal. The memory 230 is connected to the processor 250 and stores various information for driving the processor 250. The memory 230 may be embodied in a medium such as RAM, such as dynamic random access memory, Rambus DRAM, synchronous DRAM, and static RAM. The memory 230 may be inside or outside the processor 250 and may be connected to the processor 250 by various well-known means.

The processor 250 may be implemented as a central processing unit, other chipset, microprocessor, or the like, and the layers of the air interface protocol may be implemented by the processor 250. The processor 250 includes a channel estimator 251, a cell interference measurer 253, and a reporter 255.

Here, the channel estimator 251 receives a physical random access channel preamble according to the dedicated physical random access channel resource configuration signal from the terminal 600 and estimates an uplink channel state with the terminal 600.

The cell interference measuring unit 253 measures an interference signal due to a neighboring cell. That is, a strong interference signal is measured according to a predefined criterion in a specific UL band through a backhaul network.

The reporter 255 transmits the uplink channel estimation result received from the channel estimator 251 to the base station control apparatus 500. In addition, the cell interference signal transmitted from the cell interference measurement unit 253 is transmitted to the base station control apparatus 500.

Next, referring to FIG. 5, the base station control apparatus 500 includes a communication unit 510, a memory 530, and a processor 550.

Here, the communication unit 510 is connected to the processor 550 to transmit and receive a radio signal. The communication unit 510 may include a baseband circuit for processing a radio signal. The memory 530 is connected to the processor 550 and stores various information for driving the processor 550. The memory 530 may be implemented as a medium such as a RAM such as dynamic random access memory, RAM bus DRAM, synchronous DRAM, static RAM, or the like. The memory 530 may be inside or outside the processor 550, and may be connected to the processor 550 by various well-known means.

The processor 550 may be implemented as a central processing unit or other chipset, microprocessor, or the like, and the layers of the air interface protocol may be implemented by the processor 550. The processor 550 includes a target determiner 551, an indicator 553, and a processor 555.

The target determiner 551 determines a target terminal that requires a multi-uplink channel measurement instruction.

In this case, the target determiner 551 may determine the target terminal based on the measurement report. In general, in a cellular system, a channel quality indicator (CQI, Channel Quality Information (CSI) or Channel State Information (CSI) is defined to report. In addition, in order to support handover according to the movement of the terminal 600 separately, for example, when the downlink channel estimation result with the serving cell 300 is less than or equal to a predetermined threshold, the terminal 600 Downlink channel estimation results for the neighboring cell 400 as well as the serving cell 300 currently connected are defined to be transmitted through the PUSCH in the form of measurement report RRC signaling.

Accordingly, the target determination unit 551 may multi-up based on the downlink channel estimation result received through the channel quality indicator (CQI) or channel state information (CSI) reporting through the PUCCH or the measurement report Rc signaling through the PUSCH. The terminal 600 requiring the link channel estimation may be determined.

In addition, the target determiner 551 may determine the target terminal based on the neighbor base station request. That is, by receiving the cell interference signal from the neighbor base station 200, it is possible to determine the multi-uplink channel estimation for the terminal 600 scheduled in the uplink band where the cell interference is measured.

The indicator 553 instructs the serving base station 100 and the neighbor base station 200 to multi-uplink channel estimation.

The processor 555 receives the uplink channel estimation result from the serving base station 100 and the neighboring base station 200 with the terminal 600, respectively, and performs multi-uplink channel estimation. That is, by comparing and analyzing the results of uplink channel estimation, it is possible to determine whether to implement downlink cooperative communication between cells, whether to handover the terminal 600, and whether to implement the uplink path reconfiguration of the terminal 600.

Next, referring to FIG. 6, the terminal 600 includes a communication unit 610, a memory 630, and a processor 650.

Here, the communication unit 610 is connected to the processor 650, and transmits and receives a radio signal. The communication unit 610 may include a baseband circuit for processing a radio signal. The memory 630 is connected to the processor 650 and stores various information for driving the processor 650. The memory 630 may be embodied in a medium such as RAM, such as dynamic random access memory, Rambus DRAM, synchronous DRAM, and static RAM. The memory 630 may be inside or outside the processor 650 and may be connected to the processor 650 through various well-known means.

The processor 650 may be implemented as a central processing unit or other chipset, microprocessor, or the like, and the layers of the air interface protocol may be implemented by the processor 650. The processor 650 includes an uplink channel manager 651, a downlink channel manager 653, and a handover controller 655.

The uplink channel manager 651 generates a physical random access channel preamble according to the dedicated physical random access channel resource configuration signal received from the serving base station 100 and transmits the generated physical random access channel preamble to the serving base station 100 and the neighbor base station 200. do.

The downlink channel manager 653 measures the downlink channel with the serving base station 100 periodically or aperiodically and transmits the downlink channel to the serving base station 100. In this case, when the downlink channel estimation result is less than or equal to a predetermined reference value, the downlink channel estimation result may be reported to the serving base station 100.

In addition, the downlink channel manager 653 estimates a downlink channel with the neighbor base station 200 and transmits the downlink channel to the neighbor base station 200.

The handover controller 655 performs best cell selection according to a radio link failure procedure.

An uplink channel estimation method will be described for each embodiment based on the above description. At this time, it will be described in connection with the configuration of Figures 1 to 6, and the same reference numerals are used.

Referring to FIG. 7, the target determiner 551 of the base station control apparatus 500 determines a target terminal 600 requiring multi-uplink channel estimation (S101).

Here, the target terminal 600 may be a terminal located in a boundary area between two or more base stations managed by the base station control apparatus 500 itself. Alternatively, the base station control apparatus 500 may be a terminal located at a boundary area between two or more base stations managed by itself and the other base station control apparatus.

Next, the indication unit 553 of the base station control apparatus 500 instructs the multi-uplink channel estimation instruction to the serving base station 100 and the adjacent base station 200 to which the target terminal 600 determined in step S101 is currently connected (Initiation of multi). -UL channel measurement) is transmitted (S103, S105).

Next, the allocation unit 151 of the serving base station 100 instructs a random access procedure by transmitting a physical downlink control channel command (PDCCH order) to the target terminal 600 (S107).

In this case, the physical downlink control channel command (PDCCH order) includes physical random access channel (PRACH) resource allocation information, and the format is PDCCH format 1A. Here, the PDCCH format 1A is scrambled with a cell radio network temporary identifier (C-RNTI) of the target terminal 600.

The physical random access channel (PRACH) resource allocation information may also include a preamble index (6 bits) for generating a dedicated physical random access channel (PRACH) preamble and a physical random access for transmitting the preamble. A physical random access channel mask index (PRACH Mask Index, 4 bits) that is a channel resource index (PRACH resource index) value.

Next, the uplink channel manager 651 of the target terminal 600 generates a dedicated physical random access channel preamble (dedicated PRACH preamble) generated according to the physical random access channel (PRACH) resource allocation information received in step S107. The transmission is performed to the neighbor base station 200 (S109).

In this case, the uplink channel manager 651 of the target terminal 600 uses a preamble index information region of a physical downlink control channel command (PDCCH order) according to physical random access channel configuration (PRACH configuration) information. The configured preamble is transmitted through the physical random access channel resource index (PRACH resource index) set through the physical random access channel mask index (PRACH Mask Index).

Here, the physical random access channel configuration (PRACH configuration) information is received through the cell-specific system information of the serving base station (100). The physical random access channel configuration (PRACH configuration) information includes a physical random access channel configuration index (PRACH configuration index), a physical random access channel-frequency offset (PRACH-FrequencyOffset), random access channel-root-sequence (RACH_ROOT_SEQUENCE) .

Next, the channel estimator 251 of the neighboring base station 200 estimates an uplink channel state with the target terminal 600 by using the dedicated physical random access channel preamble received in step S109. (S111). The report unit 255 of the neighbor base station 200 reports the estimation result to the base station control apparatus 500 (S113).

As such, the base station controller 500 uses the dedicated physical random access channel preamble generated according to the dedicated physical random access channel resource information allocated by the serving base station 100. The uplink channel estimation result between the neighbor base station 200 and the target terminal 600 may be obtained from the neighbor base station 200.

In addition, the uplink channel manager 651 of the target terminal 600 predicates the dedicated physical random access channel generated according to the dedicated physical random access channel (dedicated PRACH) resource allocation information received in step S107. The PRACH preamble is also transmitted to the serving base station 100 (S115).

Here, steps S109 and S115 are described as being made in separate steps with a time difference, but steps S109 and S115 may be performed at the same time. That is, steps S109 and S115 may be one operation of the target terminal 600 transmitting a dedicated physical random access channel preamble. The physical random access channel preamble transmitted in this way is simultaneously received by the serving base station 100 and the neighbor base station 200, respectively.

Then, the estimator 153 of the serving base station 100 estimates an uplink channel state with the target terminal 600 by using the dedicated physical random access channel preamble received in step S115. (S117). The reporting unit 155 of the serving base station 100 reports the estimation result to the base station control apparatus 500 (S119).

Then, the processor 555 of the base station control apparatus 500 estimates the multi-uplink channel between the target terminal 600 and the plurality of base stations based on the estimation results received in steps S113 and S119 (S121).

That is, the processing unit 555 of the base station control apparatus 500 compares and analyzes the uplink channel estimation result between the serving base station 100 and the neighboring base station 200 and the terminal 600 received in steps S113 and S119, respectively, between cells. Whether to implement downlink cooperative communication, whether to handover the terminal 600, and whether to implement the uplink path reconfiguration of the terminal 600 may be determined.

As described above, according to steps S101 to S121, the target terminal 600 uses a random access procedure based on a physical downlink control channel command (PDCCH order) defined in the 3GPP LTE / LTE-A system. Transmit a dedicated physical random access channel preamble (dedicated PRACH preamble) and let the neighboring base station 200 receive it.

In this case, the physical random access channel configuration (PRACH configuration) information and the physical downlink control channel command (PDCCH order) is a value set in the serving base station 100 to which the target terminal 600 is currently connected (connection). Therefore, the neighbor base station 200 is allocated to the target terminal 600 through cell-specific physical random access channel configuration (cell-specific PRACH configuration) information and the physical downlink control channel command (PDCCH order) of the serving base station 100 The preamble index and the physical random access channel mask index (PRACH Mask Index) value should be known and obtained through the base station control apparatus 500 or the serving base station 100 directly transmitted to the adjacent base station 200. Do it.

Referring to FIG. 8, the target determiner 551 of the base station control apparatus 500 determines a target terminal 600 requiring multi-uplink channel estimation (S201).

Next, the indicating unit 553 of the base station control apparatus 500 transmits a multi-uplink channel estimation instruction to the serving base station 100 and the adjacent base station 200 to which the target terminal 600 determined in step S201 is currently connected (S203). , S205).

Next, the allocation unit 151 of the serving base station 100 instructs the target terminal 600 to fake handover (Radio Hand Control) using Radio Resource Control (RRC) signaling (S207).

At this time, the handover is instructed by using a radio resource control connection reconfiguration message transmitted by the serving base station 100 during the existing handover.

In addition, the allocation unit 151 of the serving base station 100 includes physical random access channel configuration (PRACH configuration) information through the mobility control information (mobility control information) region of the radio resource control connection reconfiguration (RRC Connection Reconfiguration) message System information of the neighbor base station 200 and physical random access channel (PRACH) resource allocation information for generating a dedicated physical random access channel preamble (PRACH) resource allocation information are set and transmitted. Here, the physical random access channel (PRACH) resource allocation information may include a preamble index, a preamble mask index, a T304 timer setting information, a preamble TransMax, and the like. Include.

Next, if the RRC connection reconfiguration message is received in step S207, the handover controller 655 of the target terminal 600 performs a handover operation.

In this case, since the physical random access channel (PRACH) resource allocation information is included in the mobility control information area of the RRC connection reconfiguration message, an uplink channel manager of the target terminal 600 ( 651 generates a dedicated physical random access channel (PRACH) preamble according to the physical random access channel (PRACH) resource allocation information and transmits it to the neighbor base station 200 (S209).

Next, the adjacent base station 200 estimates an uplink channel state with the target terminal 600 using the dedicated physical random access channel preamble received in step S209 (S211). The estimation result is reported to the base station control apparatus 500 (S213).

In addition, the target terminal 600 generates a dedicated physical random access channel (PRACH) preamble according to the physical random access channel (PRACH) resource allocation information received in step S207, and also transmits it to the serving base station 100. (S215).

Then, the serving base station 100 estimates an uplink channel state with the target terminal 600 using the dedicated physical random access channel preamble received in step S215 (S217). The estimation result is reported to the base station control apparatus 500 (S219).

Here, steps S209 and S215 are a single operation of transmitting a dedicated physical random access channel preamble (dedicated PRACH preamble) from the perspective of the target terminal 600, the receiving side is the serving base station 100 and the adjacent Since it is a base station 200, it is only shown as a separate step in the figure.

In addition, the physical random access channel preamble (dedicated PRACH preamble) transmission is performed according to the handover operation of the target terminal 600. Therefore, two embodiments are possible in which the physical random access channel preamble is received only at the neighbor base station 200 or at both the serving base station 100 and the neighbor base station 200. Accordingly, S215, S217, S219, and S221 are not essential steps and may be optional steps. As such, the indication unit 153 of the serving base station 100 may configure the radio resource control connection reconfiguration in a fake handover method (RRC Connection). A dedicated PRACH preamble transmission of the target terminal 600 is indicated through a mobility control information area of a reconfiguration message.

In this case, neither the serving base station 100 nor the neighboring base station 200 transmits any response message to the physical random access channel preamble transmission of the target terminal 600.

Meanwhile, the processor 555 of the base station control apparatus 500 estimates a multi-uplink channel between the target terminal 600 and the plurality of base stations based on the estimation results received in steps S213 and S219 (S221).

Thereafter, the handover controller 655 of the target terminal 600 determines whether the condition set in the RRC Connection Reconfiguration message is satisfied (S223). For example, it may be determined whether the T304 timer expires according to the T304 timer value. Alternatively, it may be determined whether the number of dedicated physical random access channel preamble transmissions reaches a preamble trans max value.

Next, if the condition is satisfied in step S223, the handover control unit 655 performs an optimal cell selection according to a radio link failure procedure (S225). Reenter the network.

In this case, since the handover control unit 655 of the target terminal 600 is located within the downlink coverage of the serving base station 100, the handover control unit 655 re-enters the cell of the serving base station 100 (S227).

Referring to FIG. 9, the target determiner 551 of the base station control apparatus 500 determines a target terminal 600 requiring multi-uplink channel estimation (S301).

Next, the indicating unit 553 of the base station control apparatus 500 transmits a multi-uplink channel estimation instruction to the serving base station 100 and the adjacent base station 200 to which the target terminal 600 determined in step S301 is currently connected ( S303, S305).

Next, the allocation unit 151 of the serving base station 100 transmits a radio resource control signaling (RRC signaling) message including physical random access channel (PRACH) resource allocation information to the target terminal 600 (S307).

Then, the uplink channel manager 651 of the target terminal 600 performs the dedicated physical random access channel preamble (dedicated PRACH preamble) generated according to the physical random access channel (PRACH) resource allocation information received in step S307. It transmits to the adjacent base station 200 (S309).

Here, according to one embodiment, the dedicated physical random access channel preamble (dedicated PRACH preamble) may be configured to be transmitted through the resource region of the physical uplink public channel (PUSCH) of the neighbor base station 200 have. In this case, the RRC signaling message includes time / frequency resource allocation information, random access channel-root-sequence (RACH_ROOT_SEQUENCE), preamble format, and preamble index. index), and power control information including transmission power (Tx Power). In this case, time / frequency resource allocation information includes physical random access channel-frequency offset (PRACH-FrequencyOffset), radio frame / subframe index for initial transmission, Period information (Periodicity) and the like.

In addition, according to another embodiment, the dedicated physical random access channel preamble (dedicated PRACH preamble) may be configured to be transmitted through the physical random access channel opportunity (PRACH opportunity) of the adjacent base station 200. In this case, the RRC signaling message includes physical random access channel configuration (PRACH configuration) information, preamble index, preamble mask index, power control information, and period. (periodicity) information and the like. Here, the physical random access channel configuration information (PRACH configuration information) is a physical random access channel configuration index (PRACH configuration index), physical random access channel-frequency offset (PRACH-FrequencyOffset), random access channel-root-sequence (RACH_ROOT_SEQUENCE) Include.

Next, the channel estimator 251 of the neighboring base station 200 estimates an uplink channel state with the target terminal 600 using the physical random access channel preamble received in step S309 (S311). . The estimation result is reported to the base station controller 500 (S313).

In addition, the uplink channel manager 651 of the target terminal 600 performs the dedicated physical random access channel preamble (dedicated PRACH preamble) generated according to the physical random access channel (PRACH) resource allocation information received in step S307. It also transmits to the serving base station 100 (S315).

Here, the steps S309 and S315 are described as being made in separate steps with a time difference, but the steps S309 and S315 may be performed at the same time. That is, step S309 and step S315 may be one operation of the target terminal 600 transmits a dedicated physical random access channel preamble (dedicated PRACH preamble). The physical random access channel preamble transmitted in this way is simultaneously received by the serving base station 100 and the neighbor base station 200, respectively.

Then, the estimator 153 of the serving base station 100 estimates an uplink channel state with the target terminal 600 using the dedicated physical random access channel preamble received in step S315. (S317). The estimation result is reported to the base station controller 500 (S319).

Then, the processor 555 of the base station control apparatus 500 estimates the multi-uplink channel between the target terminal 600 and the plurality of base stations based on the estimation results received in steps S313 and S319 (S321).

As described above, according to steps S301 to S321, in addition to uplink channel estimation with the serving base station 100, a channel estimation procedure with the neighboring base station 200 is newly defined through a physical random access channel preamble (PRACH preamble). Higher layer (RRC) signaling for transmitting configuration information may be defined.

7, 8 and 9, the target terminal 600 may transmit a dedicated physical random access channel preamble (dedicated PRACH preamble) a plurality of times periodically or aperiodically.

7, 8, and 9 will be described with reference to an embodiment in which the target determiner 551 of the base station control apparatus 500 determines a terminal requiring multi-uplink channel estimation.

Referring to FIG. 10, the downlink channel manager 653 of the target terminal 600 estimates a downlink channel of a serving cell currently being accessed (S401). The estimated result is periodically or aperiodically reported to the serving base station 100 through the uplink control channel (PUCCH) (S403).

Then, the reporting unit 255 of the serving base station 100 reports the estimation result received in step S403 to the base station control apparatus 500 (S405).

Next, the target determiner 551 of the base station control apparatus 500 determines whether the corresponding terminal is a terminal requiring multi-uplink channel estimation based on the downlink channel estimation result received in step S405 (S407). For example, if the downlink channel estimate value satisfies a predefined threshold condition, the downlink channel estimate may be determined as a terminal located at a cell boundary and may be determined as a terminal requiring a multi-uplink channel estimation indication.

Referring to FIG. 11, the downlink channel manager 653 of the target terminal 600 estimates a downlink channel of a serving cell currently being accessed (S501).

At this time, it is determined whether the estimation result satisfies a predefined condition (S503). For example, it may be determined whether a specific situation for handover support according to the movement of the terminal, that is, the result of downlink channel estimation with the serving cell is less than or equal to a predetermined threshold.

Next, when the predefined condition is satisfied, the downlink channel manager 653 of the target terminal 600 reports the estimation result periodically or aperiodically to the serving base station 100 through the uplink control channel (PUCCH). (S505). Then, the reporting unit 155 of the serving base station 100 reports the estimation result received in step S505 to the base station control apparatus 500 (S507).

In addition, the downlink channel manager 653 of the target terminal 600 estimates the downlink channel of the neighbor cell (S509), and reports the estimation result to the neighbor base station 200 (S511). Then, the report unit 255 of the adjacent base station 200 reports the estimation result received in step S511 to the base station control apparatus 500 (S513).

Then, the target determiner 551 of the base station control apparatus 500 determines whether the corresponding terminal is a terminal requiring multi-uplink channel estimation based on the downlink channel estimation results received in steps S507 and S513 (S515). .

As such, the terminal is defined to transmit the downlink channel estimation result for the neighboring cell as well as the serving cell to which the terminal is currently connected in the form of measurement report RRC signaling.

Referring to FIG. 12, the cell interference measuring unit 253 of the adjacent base station 20 measures a strong cell interference signal for a specific UL band through a backhaul network (S601). If so, the measurement result is reported to the base station control apparatus 500 (S603).

Then, the target determiner 551 of the base station control apparatus 500 determines a terminal that requires multi-uplink channel estimation based on the measurement result of the cell interference signal reported in step S603 (S605).

Accordingly, dedicated PRACH resources for multi-uplink channel estimation may be allocated to a UE scheduled in a specific uplink band where a cell interference signal is detected.

The embodiments of the present invention described above are not only implemented through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims

An uplink channel manager for generating a physical random access channel preamble according to the random access channel resource configuration information allocated from the serving base station; And

A communication unit for transmitting the physical random access channel preamble to an adjacent base station according to a request of the uplink channel manager;

The physical random access channel preamble is a terminal used by the neighboring base station to estimate the uplink channel.
The method of claim 1,

The communication unit,

Transmit the physical random access channel preamble to a serving base station according to a request of the uplink channel manager;

The physical random access channel preamble is a terminal used by the serving base station to estimate the uplink channel.
The method of claim 2,

The uplink channel manager,

And requesting the communication unit to transmit the physical random access channel preamble periodically or aperiodically a plurality of times.
The method of claim 1,

The uplink channel manager,

And obtaining the allocated random access channel resource configuration information from the physical downlink control channel command received according to the random access procedure instruction from the serving base station.
The method of claim 4, wherein

The allocated random access channel resource configuration information,

A preamble index, a physical random access channel resource index, and a physical random access channel mask index,

The uplink channel manager,

The physical random access channel preamble generated using the preamble index is set through a preamble index information region of a physical downlink control channel command according to physical random access channel configuration information, and the physical random access channel mask index is set. A terminal for transmitting to the adjacent base station through the physical random access channel resource index set through.
The method of claim 5,

The uplink channel manager,

And a terminal for receiving the physical random access channel configuration information through cell specific system information of the serving base station.
The method of claim 1,

The uplink channel manager,

And obtaining the allocated random access channel resource configuration information from the mobility control information region of the radio resource control connection reconfiguration message received according to a fake handover indication from the serving base station.
The method of claim 7, wherein

The radio resource control connection reconfiguration message,

System information of the neighboring base station and the allocated random access channel resource setting information;

The allocated random access channel resource configuration information,

A terminal including a preamble index, a preamble mask index, timer information and preamble transmission maximum information.
The method of claim 8,

When the radio resource control access reconfiguration message including the allocated random access channel resource configuration information is received, request the generation and transmission of the physical random access channel preamble to the uplink channel manager, and a timer according to the timer information When expired, the handover control unit performs network reentry by selecting an optimized cell

Terminal further comprising.
The method of claim 8,

When a radio resource control access reconfiguration message including the allocated random access channel resource configuration information is received, requesting generation and transmission of the physical random access channel preamble to the uplink channel manager, and the physical random access channel preamble A handover control unit performing network reentry by selecting an optimized cell when the number of times of transmission satisfies the maximum number of times of preamble transmission information

Terminal further comprising.
The method of claim 1,

The uplink channel manager,

A terminal for receiving a radio resource control signaling (RRC Signaling) message including the allocated random access channel resource configuration information from the serving base station.
The method of claim 11,

The uplink channel manager,

And transmitting the physical random access channel preamble to the neighbor base station through the resource region of the physical uplink shared channel of the neighbor base station.
The method of claim 11,

The uplink channel manager,

And transmitting the physical random access channel preamble to the neighbor base station through a physical random access channel opportunity (PRACH opportunity) of the neighbor base station.
The method of claim 1,

Periodically or aperiodically, a result of estimating a downlink channel with the serving base station is transmitted to the serving base station, and if the result of estimating the downlink channel satisfies a predetermined threshold condition, the terminal is downlink with the neighboring base station. The terminal further includes a downlink channel management unit for transmitting a result of estimating a link channel to the neighboring base station.
A method of estimating an uplink channel by a base station controller for controlling and managing a plurality of base stations,

Receiving an uplink channel estimation result between the terminal and the neighboring base station using a random access channel preamble allocated by the serving base station accessed by the terminal from the base station adjacent to the terminal; And

Performing multi-uplink channel estimation for inter-cell cooperative communication using an uplink channel estimation result between the terminal and the adjacent base station;

Uplink channel estimation method comprising a.
The method of claim 15,

Receiving an uplink channel estimation result between the terminal and the serving base station using the random access channel preamble from the serving base station;

Performing the multi-uplink channel estimation,

And performing multi-uplink channel estimation between the terminal and a plurality of base stations based on uplink channel estimation results received from each of the serving base station and the adjacent base station.
The method of claim 16,

Performing the multi-uplink channel estimation,

And determining whether to implement inter-cell downlink cooperative communication by determining whether the terminal is located in an area requiring downlink cooperative communication between cells.
The method of claim 16,

Performing the multi-uplink channel estimation,

Uplink channel estimation method comprising the step of determining whether the terminal handover.
The method of claim 16,

Performing the multi-uplink channel estimation,

Uplink channel estimation method comprising the step of determining whether to implement the uplink rerouting of the terminal transmitting the uplink to the adjacent base station while maintaining the downlink with the serving base station.
The method of claim 15,

Before receiving an uplink channel estimation result between the terminal and the neighbor base station,

Determining a target terminal requiring the multi-uplink channel estimation; And

Instructing multi-uplink channel estimation to the serving base station to which the target terminal is connected;

Uplink channel estimation method further comprising.
The method of claim 20,

The determining step,

Receiving a downlink channel estimation result between the terminal and the serving base station from the serving base station; And

Determining the target terminal based on the downlink channel estimation result

Uplink channel estimation method comprising a.
The method of claim 20,

The determining step,

Receiving a downlink channel estimation result from the serving base station between the terminal requiring handover and the serving base station;

Receiving a downlink channel estimation result between the terminal requiring handover and the neighbor base station from the neighbor base station; And

Determining the target terminal based on respective downlink channel estimation results between the serving base station and the neighbor base station;

Uplink channel estimation method comprising a.
The method of claim 20,

The determining step,

Receiving a cell interference signal in a specific frequency band from the adjacent base station; And

Determining, as the target terminal, a terminal scheduled in the specific frequency band where the cell interference signal is generated;

Uplink channel estimation method comprising a.
A serving base station for allocating random access channel resources for uplink channel estimation to a terminal located in a cell boundary region;

An adjacent base station receiving a physical random access channel preamble generated according to the random access channel resource allocated from the serving base station from the terminal and estimating an uplink channel with the terminal using the physical random access channel preamble ; And

And a base station control device for receiving a result of estimating an uplink channel from the neighbor base station and estimating a multi-uplink channel for inter-cell cooperative communication.
The method of claim 24,

The serving base station,

Using the physical random access channel preamble received from the terminal, transmits a result of estimating an uplink channel with the terminal to the base station controller,

The base station control device,

And a multi-uplink channel estimation between the terminal and a plurality of base stations based on uplink channel estimation results received from each of the serving base station and the adjacent base station.
The method of claim 24,

The serving base station and the neighbor base station,

Communication system connected with the same base station control device or different base station control device.
The method of claim 24,

The serving base station and the neighboring base station are wireless signal processing apparatuses that form respective independent cells, and the base station control device is connected to the serving base station and the neighboring base station to perform a base station control management function and is centrally installed in a communication station. Communication system comprising a cloud-based base station structure that is implemented as a virtual server.
The method of claim 27,

The serving base station and the neighbor base station,

A communication system for forming each cell included in the inter-cell cooperative communication group for the terminal located in the cell boundary region.
The method of claim 28,

And a serving system forming a heterogeneous network in which the serving base station and the neighboring base station overlap each other.
The method of claim 29,

The serving base station and the neighbor base station,

And a plurality of small cells within the macro cell and within the macro cell having a cell radius of a smaller size than the macro cell.