KR101862839B1 - Method for estimating uplink channel - Google Patents

Abstract

An uplink channel estimation method and a communication system are provided. Here, the uplink channel estimation method includes a first sounding reference signal setting parameter for estimating an uplink channel with a serving base station, and a second sounding reference signal setting parameter for estimating an uplink channel with a neighboring base station, Receiving a second sounding reference signal setting parameter from the serving base station; Transmitting a first sounding reference signal generated based on the first sounding reference signal setting parameter to the serving base station; And transmitting a second sounding reference signal generated based on the second sounding reference signal setting parameter to the neighboring base station.

Description

[0001] METHOD FOR ESTIMATING UPLINK CHANNEL [0002]

The present invention relates to an uplink channel estimation method.

Due to the introduction of Machine Type Communication (MTC) and the spread of smartphones, the number of terminals requiring wireless connection is increasing rapidly. As a result, there is a growing demand for supporting a high data rate for each terminal. In this environment, in order to efficiently manage the allocated radio resources and to support the high transmission rate, the wireless base stations use a digital unit (hereinafter referred to as 'DU') and a radio unit (hereinafter referred to as 'RU' And each RU forms an independent cell, thereby trying to maximize the frequency reuse efficiency.

In addition, a heterogeneous network (Het-Net) scenario in which the cell size covered by each RU is varied due to transmission power imbalance between RUs is becoming common.

In the Het-Net, various cooperative communication schemes between RUs to ensure a high data rate for a UE located in a cell boundary region, and an independent downlink path establishment due to an imbalance in coverage between the downlinks (that is, (RU) as a transmission point (hereinafter referred to as TP) for transmitting a downlink signal and a reception point (collectively referred to as 'RP' hereinafter) for receiving an uplink signal from the corresponding terminal, Is also proposed.

However, in order to apply the evolved cooperative communication scheme, it is basically necessary to measure an uplink channel from a serving base station connected to an arbitrary terminal, as well as a measure of an uplink channel with the base station adjacent to the corresponding terminal.

In particular, a cooperative communication scheme between adjacent base stations has been proposed in a CoMP scenario in order to increase the uplink and downlink data rates of a UE located in a cell boundary region. In this case, in the case of a UE located in a cell boundary region, an uplink channel estimation scheme with neighboring base stations is required for cooperative communication.

In the current 3GPP LTE / LTE-A system, an arbitrary UE periodically or non-periodically transmits a Sounding Reference Signal (UL) signal for uplink channel state measurement for uplink channel estimation with a base station , Hereinafter referred to as " SRS ").

Generally, in the case of the SRS for measuring the uplink channel state, the UE transmits a radio resource control (RRC) parameter set from a serving BS to which the UE belongs . The RRC parameters include a cell-specific SRS subframe and SRS bandwidth, a UE-specific SRS bandwidth, a hopping pattern, a frequency domain position, domain position, periodicity, a subframe configuration, an antenna configuration, a base sequence index, and a cyclic shift index. have.

The UE transmits the SRS according to a UE-specific parameter in an uplink subframe / bandwidth region where a cell-specific parameter is satisfied.

Therefore, a scheme has been proposed in which the uplink channel measurement between the UE and the adjacent cell is possible by receiving the SRS transmission of the UE located in the cell boundary region not only in the serving BS but also in the neighbor BS. That is, the necessity of measuring an uplink channel with a plurality of base stations for cooperative communication has arisen, and a scheme has been proposed in which the SRS configuration information is shared with an adjacent base station so that it can be received by an adjacent base station.

However, since the conventional SRS is generated based on a physical cell ID (hereinafter, referred to as 'PCI') of a base station to which the UE belongs, it is impossible for other neighboring base stations to receive the SRS generated in the serving base station.

In addition, when the cell size between adjacent cells is different in the Het-Net, the uplink signal of the UE that has set up the uplink synchronization information (hereinafter, referred to as 'TA') based on the reception timing at the serving base station It is also unclear whether or not it is received synchronously with the adjacent base station.

Since the SRS setting information is determined by the parameters of the serving BS, even if the SRS setting information is shared with the neighbor BS, the neighbor BS must satisfy at least the following two conditions in order to receive the SRS.

1) Providing SRS sequence and resource allocation scheme that can be received in a plurality of cells

2) It is possible to apply the same uplink synchronization TA and Timing Alignment between the serving cell and the adjacent cell in the cell boundary region, or to set up a plurality of uplink synchronization (TA) settings in the UE

As described above, the conventional SRS transmission scheme considering only the uplink channel estimation with a single base station fails to provide a sufficient uplink channel estimation result to support various cooperative communication schemes in the CoMP scenario and HetNet.

Also, since the application range of the uplink channel estimation method with a plurality of base stations limited to the limited scenario becomes narrow, it is necessary to design a plurality of uplink channel estimation techniques applicable to various cell deployment scenarios It is true.

Also, the TA1 value, which is the uplink timing synchronization information with the serving base station, and the TA2 value, which is the timing synchronization information for transmitting the uplink signal to the adjacent base station, may be different from each other.

In particular, in the Het-Net, which is a generalized cell structure, even if the downlink synchronization between cells is coincident due to the difference of the inter-cell coverage, the uplink synchronization between the cells due to the difference of the propagation delay of the uplink Differences can occur. Therefore, even when a reference signal for uplink channel estimation is transmitted to an adjacent base station, it is necessary to acquire the uplink synchronization information TA2 from the neighbor base station.

SUMMARY OF THE INVENTION The present invention provides a method for estimating an uplink channel of multiple cells using a sequential sounding reference signal transmission scheme.

According to an aspect of the present invention, an uplink channel estimation method is a method for a UE to estimate an uplink channel. In addition to a first sounding reference signal configuration parameter for uplink channel estimation with a serving base station, Receiving a second sounding reference signal setting parameter for link channel estimation from the serving base station; Transmitting a first sounding reference signal generated based on the first sounding reference signal setting parameter to the serving base station; And transmitting a second sounding reference signal generated based on the second sounding reference signal setting parameter to the neighboring base station.

In this case,

And receiving the second sounding reference signal setting parameter from the serving base station through UE-specific radio resource control signaling.

In addition,

Receiving a sounding reference signal setting parameter from the serving base station through UE-specific radio resource control signaling including a sounding reference signal ID; And checking whether the sounding reference signal setting parameter is the second sounding reference signal setting parameter using the sounding reference signal ID.

In addition,

Receiving a sounding reference signal setting parameter from the serving base station through UE-specific radio resource control signaling; Receiving triggering information of an aperiodic sounding reference signal through a physical downlink control channel on which an indicator is defined; And checking whether the sounding reference signal setting parameter is the second sounding reference signal setting parameter using the indicator.

Also, before the step of allocating,

And receiving second uplink synchronization information that is uplink synchronization information with the neighbor base station in addition to first uplink synchronization information that is uplink synchronization information with the serving base station.

In addition, the step of receiving the second uplink synchronization information may include:

Transmitting a physical random access channel preamble to the neighbor base station; And receiving the second uplink synchronization information from the serving base station.

In addition, the step of transmitting to the neighbor base station,

Receiving a physical downlink control channel command including random access resource allocation information from the serving base station; And transmitting a physical random access channel preamble generated according to the random access resource allocation information to the neighbor base station,

Wherein the step of receiving the second uplink synchronization information comprises:

And receiving the random access channel response message including the second uplink synchronization information from the serving base station.

In addition, the step of transmitting to the neighbor base station,

Receiving random access resource allocation information from the serving base station through upper layer signaling; And transmitting a physical random access channel preamble generated according to the random access resource allocation information to the neighbor base station,

Wherein the step of receiving the second uplink synchronization information comprises:

And receiving the second uplink synchronization information through an upper layer signaling response message.

In addition,

Transmitting a physical random access channel preamble to the neighbor base station; And second uplink synchronization information, which is uplink synchronization information with the neighbor base station, and the second sounding reference signal configuration parameter, which are the uplink synchronization information from the serving base station to the serving base station, And receiving the data.

In addition, the step of transmitting to the neighbor base station,

Receiving a physical downlink control channel command including random access resource allocation information from the serving base station; And transmitting a physical random access channel preamble generated according to the random access resource allocation information to the neighbor base station,

Wherein the receiving of the second sounding reference signal setting parameter comprises:

Receiving the random access channel response message including the second uplink synchronization information and the second sounding reference signal configuration parameter.

In addition, the step of transmitting to the neighbor base station,

Receiving random access resource allocation information from the serving base station through upper layer signaling; And transmitting a physical random access channel preamble generated according to the random access resource allocation information to the neighbor base station,

Wherein the receiving of the second sounding reference signal setting parameter comprises:

And receiving an upper layer signaling response message including the second uplink synchronization information and the second sounding reference signal configuration parameter.

In addition, the step of transmitting to the serving base station,

Periodically or non-periodically transmitting the first sounding reference signal according to the first uplink synchronization information generated based on the first sounding reference signal setting parameter to the serving base station,

The method of claim 1,

And transmitting the second sounding reference signal according to the second uplink synchronization information generated based on the second sounding reference signal setting parameter periodically or non-periodically to the neighboring base station.

According to another aspect of the present invention, there is provided a method of estimating an uplink channel by a serving base station, comprising: receiving a physical random access channel preamble from a terminal; And receiving second uplink synchronization information, which is uplink synchronization information with the neighbor base station, from the neighbor base station in addition to the first uplink synchronization information, which is uplink synchronization information with the serving base station, from the neighbor base station and transmitting the second uplink synchronization information to the terminal .

In this case,

And transmitting the second uplink synchronization information to the terminal through a response message including an uplink synchronization information ID field.

In addition, the step of transmitting to the terminal may include:

And transmitting the second uplink synchronization information to the mobile station through a response message having two or more uplink synchronization information ID regions determined according to cell overlapping degree.

In addition,

A random access channel response message or an upper layer signaling message.

The uplink channel estimation method further includes a second sounding reference signal setting parameter for uplink channel estimation with the neighbor base station in addition to the first sounding reference signal setting parameter for uplink channel estimation with the serving base station, To the terminal.

The step of allocating the second sounding reference signal setting parameter to the terminal may include:

Through the UE-specific radio resource control signaling including the sounding reference signal setting ID information area for distinguishing the first sounding reference signal setting parameter or the second sounding reference signal setting parameter from the second sounding reference signal, And assigning a signal setting parameter to the terminal.

The method further includes receiving a first sounding reference signal according to the first uplink synchronization information generated based on the first sounding reference signal setting parameter from the terminal; And transmitting a result of the uplink channel estimation based on the first sounding reference signal to the base station controller.

According to another aspect of the present invention, there is provided a method for estimating an uplink channel of an adjacent base station, comprising: receiving a physical random access channel preamble generated according to information allocated by a serving base station; Measuring uplink synchronization information between the mobile station and the neighboring base station using the physical random access channel preamble and transmitting the measured uplink synchronization information to the serving base station; Receiving a sounding reference signal generated according to the uplink synchronization information from the terminal; And reporting the uplink channel estimation result estimated using the sounding reference signal to the base station controller.

At this time, the sounding reference signal includes

And may be generated according to a sounding reference signal setting parameter for uplink channel estimation with the neighbor base station and the uplink synchronization information allocated by the serving base station.

According to another aspect of the present invention, in addition to a first sounding reference signal setting parameter for uplink channel estimation with a serving base station, a communication system further includes a second sounding reference signal setting parameter for uplink channel estimation with a neighbor base station A serving BS for receiving a first sounding reference signal generated based on the first sounding reference signal setting parameter from the MS and estimating an uplink channel; An adjacent base station for receiving a second sounding reference signal generated based on the second sounding reference signal setting parameter from the terminal and estimating an uplink channel; And a base station controller for estimating a multi-uplink channel for inter-cell cooperative communication using a result of estimating an uplink channel received from the serving base station and a result of estimating an uplink channel received from the neighbor base station .

At this time, the first sounding reference signal is generated according to first uplink synchronization information, the second sounding reference signal is generated according to second uplink synchronization information,

The serving base station may receive the second uplink synchronization information from the neighbor base station and may transmit the second uplink synchronization information to the terminal through a response message to the physical random access preamble received from the terminal .

In addition, the serving base station,

And transmits a response message including the second uplink synchronization information and the second sounding reference signal configuration parameter to the UE.

In addition, the serving base station,

And may transmit the second uplink synchronization information to the terminal through a response message including an uplink synchronization information ID field.

In addition, the serving base station,

And transmit the second sounding reference signal setting parameter to the UE through UE-specific RBOT signaling including the sounding reference signal ID.

In addition, the serving base station,

A physical downlink control channel including an indicator for identifying a sounding reference signal transmitted through the UE-specific radio resource control signaling may be transmitted to the UE.

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

And can be connected to the same base station controller or different base station controllers.

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

Each of which is a radio signal processing apparatus for forming independent cells,

The base station control apparatus includes:

And a cloud-based base station structure implemented as a virtual server connected to the serving base station and the neighbor base station, performing a base station control management function, and installed in a central office of a communication company.

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

And each cell included in the inter-cell cooperative communication group for the terminal located in the cell boundary region can be formed.

In addition, a heterogeneous network in which the serving base station and the neighbor base station having cell coverage of different sizes are arranged in an overlapping manner can be formed.

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

A macro cell and a plurality of small cells each having a cell radius smaller than that of the macro cell can be formed in the macro cell.

According to the embodiment of the present invention, not only the uplink channel estimation with the serving cell connected to the UE but also the SRS setup and transmission scheme for the uplink channel estimation with the adjacent cell. For this purpose, a second SRS setting scheme for uplink channel estimation with an adjacent base station and a transmission scheme of a terminal for the first SRS and the second SRS set are provided separately from the first SRS setting for the uplink channel estimation with the serving cell do. This enables multi-uplink channel estimation which can be applied universally in various heterogeneous networks (Het-Net) and CoMP scenarios. 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 or not the mobile terminal enters the cooperative communication area (cell boundary area).

In addition, it is possible to provide an independent path setting scheme between the uplink and the downlink, in particular, a basis for providing a base channel estimation result for determining whether the uplink path is reset.

1 is a configuration diagram of a communication system 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 illustrating a schematic configuration of a serving BS 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 a process of acquiring uplink synchronization information (TA) according to an embodiment of the present invention.
FIG. 8 is a flowchart illustrating a process of acquiring uplink synchronization information (TA) according to another embodiment of the present invention.
9 is a flowchart illustrating a process of generating a PRACH preamble according to an embodiment of the present invention.
10 is a flowchart illustrating an uplink channel estimation method according to an embodiment of the present invention.
11 is a flowchart illustrating an uplink channel estimation method according to another embodiment of the present invention.
12 is a flowchart illustrating a method of determining a target terminal according to an embodiment of the present invention.
13 is a flowchart illustrating a method of determining a target terminal according to another embodiment of the present invention.
14 is a flowchart illustrating a method of determining a target terminal according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Also, the terms " part, "" module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have.

In this specification, a terminal includes a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a user equipment , An access terminal (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 mobile subscriber station, a user equipment,

In this specification, a base station (BS) includes an access point (AP), a radio access station (RAS), a node B, an evolved NodeB (eNodeB) A base station (BTS), a mobile multihop relay (MMR) -BS, or the like, and may perform all or a part of functions of an access point, a radio access station, a Node B, an eNodeB, a base transceiver station, .

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

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

Referring to FIG. 1, a communication system to which an embodiment of the present invention is applied includes a first base station 100 having cell coverage of different sizes, and a second base station 200, It is a heterogeneous network (Het-Net). Here, although only two base stations are illustrated, they may include a plurality of base stations.

In this 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 are overlapped. The small cell 400 covers an area smaller than the macro cell 300. A plurality of small cells 400 may exist in one macro cell 300. In other words, a single macro cell 300 includes a pico cell, a micro cell, a femtocell cell, and a femtocell cell by distributed low power remote radio heads (RRH) ) Are overlapped with each other.

In addition, such a communication system includes Coordinated Multi-Point Scenarios (CoMPs) 3 and 4 (Coordinated Multi-Point Scenarios) for increasing the uplink and downlink data rates of the terminals located in the cell boundary region through cooperative communication between adjacent cells Based base station structure, which is shown in FIG.

Referring to FIG. 2, a cloud-based base station structure includes a general base station 800, a digital unit 800, and a radio unit (RU) 800 900).

A typical base station includes a processing unit corresponding to each of the DU 800 and the RU 900 in one physical system, and one physical system is installed in the service area. On the other hand, according to the cloud-based base station structure, the DU 800 and the RU 900 are physically separated and only the RU 900 is installed in the service area. And one DU 800 has control management functions for a plurality of RUs 900 forming respective independent cells. At this time, the DU 800 and the RU 900 can be connected by an optical cable.

Here, the DU 800 is a part responsible for digital signal processing and resource management control functions of the base station and is connected to a core system (not shown). It is installed in centralized areas such as Internet Data Center (IDC, Internet Data Center). In addition, the DU (800) provides various wireless technologies such as Wideband Code Division Multiple Access (WCDMA), WiBro, Long Term Evolution (LTE) Multiple DUs (800) may be operated as one.

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

Referring again to FIG. 1, the first base station 100 and the second base station 200 are implemented in the RU 900 of FIG. And can be referred to as eNB, RU, and RRH (Remote Radio Heads). In addition, the base station control apparatus 500 is implemented by the DU 800 of FIG. And is connected to and manages the first base station 100 and the second base station 200.

Although the first base station 100 and the second base station 200 are managed by the single base station controller 500, the first base station 100 and the second base station 200 may be controlled by different base station controllers Or may be managed by the device 500, respectively.

According to the cooperative multi-point (CoMP) scenario, the terminal 600 located in the cell boundary region is requested to estimate the 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 first cell 300 but located in an area that can be influenced by the second cell 400. The terminal 600 located in the cell boundary region transmits and receives signals not only to the currently connected first base station 100 but also to the second base station 200 as compared with the case where the terminal 700 located at the center of the second cell 400 transmits / And can also transmit and receive signals to and from the second base station 200, which is an adjacent base station.

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

Here, the UE 600 located in the cell boundary region receives the downlink physical channel and physical signals from the serving base station 100 (1 & cir &). 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 signals include a CRS (Common Reference Signal), a PSS (Primary Synchronization Signal), a SSS (Secondary Synchronization Signal), a CSI RS (Channel State Information-Reference Signal) and a DM RS (DeModulation-Reference Signal).

The MS 600 located in the cell boundary region may determine the uplink physical channel state between the MS 600 and the serving BS 100 and the uplink physical channel state between the MS 600 and the second BS 200, Channel and physical signals to the serving base station 100 or to the second base station 200 (2). Here, the uplink physical channel includes a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH), and the physical signal includes a sounding reference signal (SRS).

At this time, the UE 600 located in the cell boundary region receives a dedicated random access channel (RACH) resource setting signal from the serving base station 100. The demodulated RACH resource setup signal includes resource allocation information for uplink channel estimation with the neighboring cell. Then, the serving base station 100 transmits a de-scheduled RACH resource setup signal to a target terminal that is a target of multi-uplink estimation according to an instruction from the base station controller 500.

Here, the target terminal is 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. At this time, the multi-uplink channel estimation is defined as an uplink channel estimation between the target terminal 600 and two or more base stations. And the terminal 600 located in the cell boundary region will be collectively referred to as a target terminal.

Meanwhile, the target terminal 600 transmits a Physical Random Access Channel (PRACH) preamble to the neighbor base station 200 according to the de-identified RACH resource setting signal. Then, the neighbor base station 200 estimates the uplink channel state with the target terminal 600 based on the PRACH preamble, and reports the state to the base station controller 500.

Also, the target terminal 600 transmits the PRACH preamble to the serving base station 100 according to the de-identified RACH resource setting signal. Similarly, the serving base station 100 estimates the uplink channel state with the target terminal 600 based on the PRACH preamble, and reports the state to the base station controller 500.

Then, the base station controller 500 performs multi-uplink channel estimation based on the respective uplink channel states reported from the serving base station 100 and the neighbor base station 200.

That is, by estimating not only the uplink channel with the serving base station 100 to which the target terminal 600 is currently connected but also the uplink channel with the neighboring base station 200, the target terminal 600 can perform inter-cell downlink cooperation communication It is possible to determine whether or not to implement the inter-cell downlink cooperative communication by determining whether it is located in the required area. Alternatively, the handover of the target terminal 600 may be implemented. Or to implement UL Path Redirection of the target terminal 600. [ Herein, the uplink path reestablishment refers to a state in which the downlink is maintained with the serving base station 100 and only the uplink is transmitted to the neighbor base station 200.

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

3, the serving BS 100 includes a communication unit 110, a memory 130, and a processor 150.

Here, the communication unit 110 is connected to the processor 150 to transmit and receive a radio signal. The communication unit 110 may include a baseband circuit for processing a radio signal. The memory 130 is coupled 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 dynamic random access memory, a RAM such as a DRAM, a synchronous DRAM, or a static RAM. And memory 130 may be internal or external to processor 150 and may be coupled to processor 150 in a variety of well known ways.

The processor 150 may be implemented as a central processing unit (CPU) or other chipset, a microprocessor, etc., and the layers of the air interface protocol may be implemented by the processor 150. The processor 150 includes an allocation unit 151, an uplink synchronization management unit 153, a channel estimation unit 155, and a reporting unit 157.

Here, the allocation unit 151 allocates the de-identified RACH resource to the target terminal 600 according to the multi-uplink channel estimation command of the base station control apparatus 500. [

The uplink synchronization management unit 153 may further include a second uplink synchronization information additionally adjacent to the first uplink synchronization information (TA1), which is synchronization information for uplink channel estimation between the serving base station 100 and the target terminal 600, (Hereinafter, referred to as 'TA2'), which is synchronization information for uplink channel estimation between the base station 200 and the target terminal 600, to the target terminal 600.

The channel estimator 155 estimates the uplink channel state based on a first sounding reference signal (hereinafter, referred to as 'first SRS') received from the target terminal 600.

The channel estimator 155 estimates a first SRS for uplink channel estimation between the serving BS 100 and the target MS 600 using parameters of Radio Resource Control (RRC) And assigns a configuration parameter to the target terminal 600.

In addition to the first SRS configuration parameter, the channel estimation unit 155 may further include a second sounding reference signal (hereinafter, referred to as 'second SRS') for uplink channel estimation between the neighbor base station 200 and the target terminal 600 ) Setting parameters to the target terminal 600.

The reporting unit 157 receives the uplink channel estimation result from the channel estimation unit 155 and transmits the uplink channel estimation result to the base station controller 500. The reporting unit 157 receives the downlink channel estimation result received from the target terminal 600 and transmits the downlink channel estimation result to the base station controller 500.

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 to transmit and receive a radio signal. The communication unit 210 may include a baseband circuit for processing a radio signal. The memory 230 is coupled to the processor 250 and stores various information for driving the processor 250. Such memory 230 may be implemented in a medium such as RAM, such as dynamic random access memory, Rambus DRAM, synchronous DRAM, static RAM, and the like. And memory 230 may be internal or external to processor 250 and may be coupled to processor 250 in a variety of well known ways.

The processor 250 may be implemented as a central processing unit or other chipset, microprocessor, etc., and the layers of the air interface protocol may be implemented by the processor 250. The processor 250 includes an uplink synchronization management unit 251, a channel estimation unit 253, a reporting unit 255, and a cell interference measurement unit 257.

Here, the uplink synchronization manager 251 measures the TA2 and transmits the TA2 to the serving base station 100 when the DPCH preamble is received from the target terminal 600. [

The channel estimator 253 receives the multi-uplink channel estimation instruction from the base station controller 500. When the second SRS is received from the target terminal 600, the uplink channel state is estimated.

The reporting unit 255 transmits the uplink channel estimation result received from the channel estimation unit 253 to the base station controller 500. And transmits the downlink channel estimation result received from the target terminal 600 to the base station controller 500. And transmits the cell interference signal received from the cell interference measuring unit 257 to the base station controller 500.

The cell interference measurement unit 257 measures an interference signal due to the neighboring cell. That is, through the backhaul network, a strong interference signal is measured according to a predefined criterion in a specific UL band.

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 coupled to the processor 550 and stores various information for driving the processor 550. [ Such memory 530 may be implemented in a medium such as a dynamic random access memory, a RAM such as a Rambus DRAM, a synchronous DRAM, a static RAM, and the like. And memory 530 may be internal or external to processor 550 and may be coupled to processor 550 in a variety of well known ways.

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

The target determining unit 551 determines a target terminal 600 that requires a multi-uplink channel measurement indication.

At this time, the target determining unit 551 can determine the target terminal 600 based on the measurement report. Generally, in a cellular system, for channel dependent scheduling for maximizing frequency efficiency, a target terminal 600 periodically or non-periodically transmits a channel estimation result for a downlink channel through a PUCCH, which is an uplink control channel, , Channel Quality Information (CSI), or Channel State Information (CSI).

For example, if the downlink channel estimation result with the serving cell 300 is less than a predefined threshold value to support the handover according to the movement of the target terminal 600, the target terminal 600 Is defined to transmit the downlink channel estimation result for the neighboring cell 400 as well as the serving cell 300 that is currently connected through the PUSCH in the form of a measurement report RRC signaling.

Therefore, the target determining unit 551 determines whether the 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 AAL signaling through the PUSCH It is possible to determine the target terminal 600 requiring the link channel estimation.

Also, the target determining unit 551 can determine the target terminal 600 based on the neighbor base station request. That is, the multi-uplink channel estimation can be determined for the target terminal 600 scheduled in the uplink band where the cell interference is measured by receiving the cell interference signal from the neighbor base station 200.

The instruction unit 553 instructs the serving base station 100 and the neighboring base station 200 to perform multi-uplink channel estimation.

The processing unit 555 receives the uplink channel estimation result of the target terminal 600 from the serving base station 100 and the neighbor base station 200 and performs multi-uplink channel estimation. That is, each of the uplink channel estimation results are compared and analyzed to determine whether to implement inter-cell downlink cooperative communication, handover of the target terminal 600, and whether to perform uplink path resetting of the target terminal 600.

6, the target 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 to transmit and receive a radio signal. The communication unit 610 may include a baseband circuit for processing a radio signal. The memory 630 is coupled to the processor 650 and stores various information for driving the processor 650. [ Such memory 630 may be implemented in a medium such as a dynamic random access memory, a RAM such as a Rambus DRAM, a synchronous DRAM, a static RAM, and the like. And memory 630 may be internal or external to processor 650 and may be coupled to processor 650 by various well known means.

The processor 650 may be implemented as a central processing unit or other chipset, microprocessor, etc., and the layers of the air interface protocol may be implemented by the processor 650. [ The processor 650 includes an uplink synchronization acquisition unit 651, an uplink channel management unit 653, and a downlink channel management unit 655.

Here, the uplink synchronization acquisition unit 651 generates a PRACH preamble according to the de-identified RACH resource setup signal received from the serving base station 100, and transmits the generated PRACH preamble to the serving base station 100 and the neighbor base station 200, TA2 is obtained in addition to TA1 from TA1.

The uplink channel manager 653 receives a second SRS configuration parameter from the serving base station 100 in addition to the first SRS configuration parameter from the serving base station 100. Then, a first SRS according to the first SRS configuration parameter and TA1 is generated and transmitted to the serving base station 100. In addition, a second SRS according to the second SRS setup parameter and TA2 is generated and transmitted to the neighboring base station 200. [ Here, the first SRS and the second SRS are sequentially transmitted.

The downlink channel manager 655 periodically or non-periodically measures the downlink channel with the serving base station 100 and transmits the downlink channel to the serving base station 100. At this time, if the downlink channel estimation result is less than or equal to the predefined reference value, the downlink channel estimation result can be reported to the serving base station 100.

The downlink channel manager 655 estimates a downlink channel with the neighbor base station 200 and transmits the downlink channel to the neighbor base station 200.

The method for estimating the uplink channel will be described with reference to the embodiments described above. Here, the description will be made in connection with the configurations of Figs. 1 to 6, and the same reference numerals are used.

7 is a flowchart illustrating a process of acquiring uplink synchronization information (TA) according to an embodiment of the present invention.

Referring to FIG. 7, the target determining unit 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 region between two or more base stations managed by the base station control apparatus 500 itself. Or a terminal located in a boundary area between the base station control apparatus 500 itself and two or more base stations managed by another base station control apparatus.

Next, the instruction unit 553 of the base station control apparatus 500 transmits a multi-uplink channel estimation instruction (Initiation of multi) to the serving base station 100 and the neighbor base station 200 to which the target terminal 600 determined in step S101 is currently connected -UL channel measurement) (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 (PDCCH) order to the target terminal 600 (S107).

At this time, the physical downlink control channel command (PDCCH order) includes RACH resource allocation information, and the format is PDCCH format 1A. Here, the PDCCH format 1A is scrambled into a cell radio network temporary identifier (C-RNTI) of the target terminal 600.

The RACH resource allocation information includes a PRACH preamble index (6 bits) and a PRACH mask index (Mask Index, 4 bits).

Then, the uplink synchronization acquisition unit 651 of the target terminal 600 generates a PRACH preamble according to the RACH resource allocation information extracted from the physical downlink control channel command (PDCCH order) received in step S107 and transmits the PRACH preamble to the serving base station 100 (S109).

At this time, the uplink synchronization acquisition unit 651 of the target terminal 600 sets the PRACH preamble, which is set through the PRACH preamble index information area, to the PRACH preamble through the PRACH resource index set through the PRACH mask index, Information is transmitted according to the information.

Here, the PRACH configuration information is received through the cell-specific system information of the serving base station 100. A PRACH configuration index, a PRACH-Frequency offset (PRACH-FrequencyOffset), and a RACH-route-sequence (RACH_ROOT_SEQUENCE).

Then, the uplink synchronization management unit 153 of the serving base station 100 measures TA1 (S111). And transmits the RACH response message to the target terminal 600 (S113).

The uplink synchronization acquiring unit 651 of the target terminal 600 transmits the PRACH preamble generated according to the PRACH resource allocation information received in step S107 to the neighbor base station 200 (S115).

Here, the physical downlink control channel order (PDCCH order) and the PRACH configuration information are values set in the serving base station 100 to which the target terminal 600 is currently connected. Accordingly, the neighbor BS 200 transmits the cell-specific PRACH configuration information of the serving BS 100 and the preamble index allocated to the target UE 600 through the Physical Downlink Control Channel (PDCCH) order (preamble index) and PRACH mask index (Mask Index). The uplink synchronization management unit 251 of the neighbor base station 200 receives a preamble index allocated to the target terminal 600 from the allocation unit 151 of the serving base station 100, A PRACH mask index value can be obtained in advance. Alternatively, the allocation unit 151 of the serving base station 100 may acquire a preamble index and a PRACH mask index value allocated to the target terminal 600 through the base station control apparatus 500 have.

Next, the uplink synchronization management unit 251 of the neighbor base station 200 measures TA2 (S117). Then, the serving base station 200 is transmitted (S119).

Then, the uplink synchronization management unit 153 of the serving base station 200 transmits the TA2 received in step S119 to the target terminal 600 in step S121.

Here, the 'TA ID' information area may be included in the RACH response message. In this case, the uplink synchronization acquiring unit 651 of the target terminal 600 can identify the 'TA ID' information area and discriminate whether the TA included in the RACH response message is TA1 or TA2.

In this case, according to one embodiment, the 'TA ID' information region is allocated only to the serving base station 100 and the neighboring base station 200, that is, in a UL band, two TA (TA1 and TA2 ) Can only be settable. The size of the 'TA ID' information area can be determined to be 1 bit.

According to another embodiment, the 'TA ID' information area may be configured to allow two or more values to be set according to the number of TA values that the target terminal 600 can store or the number of TA values that can be set in the cell have. In this case, the number of two or more TA values is set through cell-specific system information according to the degree of cell overlap at a given base station. When two or more TA values are set as described above, the size of the 'TA ID' information area can be determined to be log2N bit (s) according to the N value, which is the settable number of the TA.

As described above, according to the steps S101 to S121, the PRACH preamble is transmitted to the neighboring base station 200 using a physical downlink control channel (PDCCH order) based random access procedure defined in the 3GPP LTE / LTE-A system The TA2 value may be measured based on the information, and may be reported to the target terminal 600 through the serving base station 200.

8 is a flowchart illustrating a process of acquiring uplink synchronization information according to another embodiment of the present invention.

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

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

Next, the allocating unit 151 of the serving base station 100 transmits RACH resource allocation information to the target terminal 600 through upper layer signaling (S207). At this time, the upper layer signaling includes Radio Resource Control (RRC) signaling.

Next, the uplink synchronization acquisition unit 651 of the target terminal 600 transmits the PRACH preamble generated according to the RACH resource allocation information acquired in step S207 to the serving base station 100 (S209).

Then, the uplink synchronization management unit 153 of the serving base station 100 measures TA1 (S211). Then, TA1 is included in the upper layer signaling response message and transmitted to the target terminal 600 (S213). At this time, the upper layer signaling response message includes an RRC response message.

Also, the uplink synchronization acquisition unit 651 of the target terminal 600 transmits the PRACH preamble generated according to the RACH resource allocation information received in step S207 to the neighbor base station 200 (S215).

Next, the uplink synchronization management unit 251 of the adjacent base station 200 measures TA2 (S217). And transmits it to the serving base station 200 (S219).

Then, the uplink synchronization management unit 153 of the serving base station 200 transmits an RRC Response message including the TA2 received in step S219 to the target terminal 600 (S221).

The process of generating the PRACH preamble by the uplink synchronization acquisition unit 651 of the target terminal 600 is shown in FIG.

At this time, each step shown in FIG. 9 may be added between steps S207 and S209 of FIG. And the upper layer signaling uses RRC signaling as an example.

9 is a flowchart illustrating a process of generating a PRACH preamble according to an embodiment of the present invention.

9, the uplink synchronization acquisition unit 651 of the target terminal 600 receives the RRC signaling message from the serving base station 100 (S301).

Next, the uplink synchronization acquisition unit 651 of the target terminal 600 determines whether the RRC signaling message received in step S301 includes the cell-specific PRACH configuration information of the neighbor base station 200 (S303).

If it is included, the uplink synchronization acquisition unit 651 of the target terminal 600 transmits the RACH resource allocation information, i.e., the PRACH preamble index and the PRACH mask index, included in the RRC signaling message, based on the cell- (S305).

If not included, the uplink synchronization acquisition unit 651 of the target terminal 600 acquires the PRACH configuration information received through the cell-specific system information of the serving base station 100 in advance The RACH resource allocation information is analyzed (S307).

Next, the uplink synchronization acquisition unit 651 of the target terminal 600 determines whether the RRC signaling message received in step S301 includes a TA ID field (S309).

At this time, if included, the uplink synchronization acquisition unit 651 of the target terminal 600 confirms the RACH resource allocation information for each ID (S311).

Next, a PRACH preamble for each TA ID is generated based on the information confirmed in step S311 (S313).

On the other hand, if it is not included, the PRACH preamble is generated based on the result of the analysis in step S305 or step S307 (S315).

A method for estimating a multi-uplink channel using SRS will be described with reference to FIGS. 10 and 11. FIG. At this time, the respective steps described in Figs. 10 to 11 are included after each step of Fig. 7 and Fig.

FIG. 10 is a flowchart illustrating an uplink channel estimation method according to an embodiment of the present invention, in which periodic SRS is transmitted.

Referring to FIG. 10, when a predetermined period according to the first SRS configuration parameter received from the serving base station 100 through RRC signaling arrives (S401), the uplink channel manager 653 of the target terminal 600 Generates a periodic first SRS according to the TA1 and the first SRS configuration parameter received from the serving base station 100 (S403).

Here, the first SRS configuration parameter includes a UE-specific SRS configuration parameter received from the serving base station 100 through RRC signaling in advance.

Then, the uplink channel management unit 653 of the target terminal 600 transmits the periodic first SRS to the serving base station 100 (S405).

Then, the channel estimation unit 155 of the serving base station 100 estimates the uplink channel based on the periodic first SRS (S407). The reporting unit 157 of the serving base station 100 reports the channel estimation result of step S407 to the base station controller 500 (S409).

In addition, the channel estimation unit 155 of the serving base station 100 allocates an additional second SRS configuration parameter to the target terminal 600 that has acquired TA2 through UE-specific RRC signaling (S411 ).

At this time, the additional second SRS configuration parameter includes all of the UE-specific SRS configuration parameters. Specifically, a cell-specific SRS subframe and an SRS bandwidth, a UE-specific SRS bandwidth, a hopping pattern, a frequency domain position ), A periodicity, a subframe configuration, an antenna configuration, a base sequence index, and cyclic shift index information .

If the UE-specific RRC signaling is the reconfiguration information for the first SRS configuration parameter with the established serving base station 100 or the second SRS configuration parameter for the neighbor base station 200, Need to be distinguished.

To this end, according to one embodiment, the UE-specific RRC signaling includes an SRS ID information area and indicates whether it is the reconfiguration information for the first SRS configuration parameter or the second SRS configuration parameter Information.

At this time, the SRS ID information area may include the VCID (Virtual Cell ID) for reusing the TA ID information area or generating the SRS sequence.

In addition, according to another embodiment, the step S411 may be merged into the step S121 of FIG. 7 or the step S221 of FIG. The second SRS setup parameter may be included with the TA2 in the RACH response message or the higher layer signaling message. In this way, there is no need for a separate indicator for identifying the second SRS configuration parameter.

On the other hand, when a period according to the second SRS configuration parameter received in step S411 is reached (S413), the uplink channel management unit 653 of the target terminal 600 determines whether the TA2 and the second SRS setting received from the serving base station 100 And generates a periodic second SRS according to the parameter (S415). The SRS generated in step S415 is transmitted to the neighboring BS 200 in step S417.

Then, the channel estimation unit 253 of the neighbor base station 200 estimates the uplink channel based on the periodic second SRS (S419). The reporting unit 255 of the neighboring base station 200 reports the estimation result in step S419 to the base station controller 500 (S421).

Then, the processing unit 555 of the base station control apparatus 500 estimates the multi-uplink channel using the estimation result reported in step S409 and the estimation result reported in step S421 (S419). That is, the processing unit 555 of the base station control apparatus 500 compares and analyzes the estimation result reported in step S409 and the estimation result reported in step S421 to determine whether to implement inter-cell downlink cooperative communication, whether the terminal 600 is handed over, It is possible to determine whether the uplink path re-establishment of the terminal 600 is implemented.

At this time, the first SRS and the second SRS are cyclically repeatedly transmitted as the periodic SRS set to the trigger type 0.

FIG. 11 is a flowchart illustrating an uplink channel estimation method according to another embodiment of the present invention, in which an aperiodic SRS is used as an embodiment.

11, an uplink channel manager 653 of the target terminal 600 generates a first SRS setup parameter and an aperiodic first SRS according to TA1 received from the serving base station 100 through RRC signaling in advance (S501).

Next, the non-periodic first SRS generated in step S501 is transmitted to the serving BS in step S503.

Next, the channel estimation unit 155 of the serving base station 100 estimates the uplink channel using the aperiodic first SRS received in step S503 (S505). Then, the estimation result is reported to the base station control apparatus 500 (S507).

Meanwhile, the channel estimation unit 155 of the serving base station 100 allocates additional second SRS configuration parameters to the target terminal 600 that has acquired TA2 through UE-specific RRC signaling (S509 ). At this time, the information is the same as the information allocated in step S411 of FIG. 10, but is set as a trigger type = 1.

Next, the channel estimation unit 155 of the serving base station 100 transmits triggering information for the aperiodic SRS transmission through the PDCCH (S511). At this time, the non-periodic transmission for the first SRS or the second SRS And a signal type indicator indicating whether to request aperiodic transmission for the non-periodic transmission. At this time, the signal type indicator may additionally define a 1-bit indication information area in the PDCCH.

10, the PDCCH may include only the triggering information, and may be configured to request non-periodic transmission for the first SRS using the SRS ID in the UE-specific RRC signaling, Or < / RTI >

Alternatively, step S509 may be merged into step S121 of FIG. 7 or step S221 of FIG. The second SRS setup parameter may be included with the TA2 in the RACH response message or the higher layer signaling message. In this way, there is no need for a separate indicator for identifying the second SRS configuration parameter.

Next, the uplink channel management unit 653 of the target terminal 600 confirms the SRS type through the PDCCH received in step S511 (S513).

Next, the uplink channel management unit 653 of the target terminal 600 generates an aperiodic second SRS according to the TA2 and the second SRS setting parameters (S515). And transmits it to the adjacent base station 200 (S517).

Next, the channel estimation unit 253 of the neighbor base station 200 estimates the uplink channel based on the aperiodic second SRS (S519). The reporting unit 255 of the neighboring base station 200 reports the estimation result in step S519 to the base station controller 500 (S521).

Then, the processing unit 555 of the base station control apparatus 500 estimates the multi-uplink channel using the estimation result reported in step S507 and the estimation result reported in step S521 (S523).

7 and 8, a description will be made of an embodiment in which the target decision unit 551 of the base station control apparatus 500 determines a target terminal requiring multi-uplink channel estimation.

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

Referring to FIG. 12, the downlink channel management unit 655 of the target terminal 600 estimates the downlink channel of the currently connected serving cell (S601). In step S603, the serving base station 100 periodically or non-periodically reports the estimation result on the uplink control channel (PUCCH).

Then, the reporting unit 157 of the serving base station 100 reports the estimation result received in step S603 to the base station controller 500 (S605).

Next, the target determining unit 551 of the base station control apparatus 500 determines whether the corresponding terminal is a target terminal 600 requiring multi-uplink channel estimation based on the downlink channel estimation result received in step S605 (S607 ).

For example, if the downlink channel estimation value satisfies a predefined threshold condition, the terminal can be determined to be a terminal located at a cell boundary and a terminal requiring a multi-uplink channel estimation indication can be determined.

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

Referring to FIG. 13, the downlink channel manager 655 of the target terminal 600 estimates the downlink channel of the currently connected serving cell (S701).

At this time, it is determined whether the estimation result satisfies the predefined condition (S703). For example, it is possible to determine whether a specific situation for supporting handover according to movement of a UE, that is, a downlink channel estimation result with a serving cell is below a predetermined threshold value.

Next, if the predefined condition is satisfied, the downlink channel management unit 655 of the target terminal 600 periodically or non-periodically reports the estimation result to the serving base station 100 via the uplink control channel (PUCCH) (S705). Then, the reporting unit 157 of the serving base station 100 reports the estimation result received in step S705 to the base station controller 500 (step S707).

In addition, the downlink channel management unit 655 of the target terminal 600 estimates the downlink channel of the adjacent cell (S709), and reports the estimation result to the adjacent base station 200 (S711). In step S713, the reporting unit 255 of the neighboring base station 200 reports the estimation result received in step S711 to the base station control device 500. [

Then, the target determining unit 551 of the base station control apparatus 500 determines whether the corresponding terminal is a target terminal 600 requiring multi-uplink channel estimation based on the downlink channel estimation result received in steps S707 and S713 (S715).

As described above, the downlink channel estimation result for the neighboring cell as well as the serving cell is defined to be transmitted in the form of measurement report RRC signaling.

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

Referring to FIG. 14, when the cell interference measuring unit 257 of the neighboring base station 200 measures a strong interference signal for a specific uplink band (UL band) through a backhaul network (S801) , And reports the measurement result to the base station control device 500 (S803).

Then, in step S805, the target determining unit 551 of the base station control apparatus 500 determines a target terminal 600 requiring multi-uplink channel estimation based on the measurement result of the cell interference signal reported in step S803.

Therefore, a dedicated PRACH resource for multi-uplink channel estimation can 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 implemented only by the apparatus and method, but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (9)

A method for a base station to estimate an uplink channel,
Receiving a physical random access channel preamble from a mobile station; And
The serving base station transmitting first uplink synchronization information with the terminal and second uplink synchronization information between the neighbor base station and the terminal received from the neighbor base station to the terminal,
The first uplink synchronization information,
When the MS transmits a first sounding reference signal to the serving BS,
Wherein the second uplink synchronization information comprises:
When the MS transmits a second sounding reference signal to the neighbor BS,
The first sounding reference signal and the second sounding reference signal,
And estimating an uplink channel state of the mobile station based on the estimated uplink channel state. The method according to claim 1,
The method of claim 1,
And the serving BS transmits the second uplink synchronization information to the MS through a response message including the uplink synchronization information ID field. 3. The method of claim 2,
The method of claim 1,
And transmitting, by the serving BS, the second uplink synchronization information to the MS through a response message having two or more uplink synchronization information ID regions determined according to the cell overlapping degree. The method of claim 3,
The response message includes:
A random access channel response message or an upper layer signaling message. The method according to claim 1,
The serving BS allocates a second sounding reference signal setting parameter for uplink channel estimation to the neighbor BS in addition to the first sounding reference signal setting parameter for the uplink channel estimation with the serving BS
Further comprising the steps of: 6. The method of claim 5,
The step of allocating the second sounding reference signal setting parameter to the terminal includes:
Specific radio resource control signaling including a sounding reference signal setting ID information area for distinguishing whether the serving BS is the first sounding reference signal setting parameter or the second sounding reference signal setting parameter, And allocating a second sounding reference signal setting parameter to the UE. 6. The method of claim 5,
Receiving, by the serving base station, a first sounding reference signal according to the first uplink synchronization information generated based on the first sounding reference signal setting parameter; And
Transmitting a result of estimating an uplink channel based on the first sounding reference signal to a base station controller
Further comprising the steps of: The method according to claim 1,
Between the receiving step and the transmitting step,
Receiving, by the neighbor base station, a physical random access channel preamble generated according to information allocated by the serving base station;
Measuring the second uplink synchronization information using the physical random access channel preamble and transmitting the second uplink synchronization information to the serving base station;
Receiving a sounding reference signal generated according to the second uplink synchronization information from the terminal; And
Reporting the uplink channel estimation result estimated using the sounding reference signal to the base station controller
Further comprising the steps of: 9. The method of claim 8,
The sounding reference signal,
Wherein the second uplink synchronization information is generated according to a second sounding reference signal setting parameter and an uplink synchronization information for uplink channel estimation with the neighbor base station assigned by the serving base station.

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