KR20180009644A - High speed moving terminal and method for communicating thereof in mobile wireless backhaul network - Google Patents

Abstract

A high speed mobile terminal comprises a plurality of pieces of terminal equipment (TE) connected to a plurality of antennas installed on the outside of a high speed mobile object in a mobile wireless backhaul network to independently communicate with a base station. The high speed mobile terminal sets each TE as secondary TE, sets TE ahead of the secondary TE on the basis of the moving direction of the high speed mobile object as primary TE of each TE set as the secondary TE, and calculates a delay time of each TE set as the secondary TE with respect to the corresponding primary TE. In addition, if similarity between a channel estimation value measured by the TE set as the primary TE and a channel estimation value measured by the TE set as the secondary TE after the delay time is satisfied with a set range, the TE set as the secondary TE transmits information on the delay time with the corresponding primary TE to the base station without feedback of information on a channel state.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-speed mobile terminal and a communication method thereof in a mobile wireless backhaul network, and a communication method thereof. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a high-speed mobile terminal in a mobile wireless backhaul network and a communication method therefor. More particularly, the present invention relates to a high-speed mobile terminal having a plurality of antennas, And to a method for efficiently communicating by adaptively adapting to a fast channel change due to a moving speed.

BACKGROUND ART In a mobile wireless backhaul network for a high-speed mobile body on which a large number of users using the Internet ride, in general, a plurality of antennas are mounted outside a high-speed mobile body, and a plurality of antennas each process signals corresponding to a plurality of antennas And serves to provide a mobile wireless backhaul for a user terminal in a passenger car by communicating with a plurality of terminal equipment and independently communicating with a base station. That is, a plurality of terminal devices serve as a mobile relay, and serve backhaul data transmitted and received from the base station to user terminals in the high-speed mobile terminal.

The backhaul data transmission / reception method using a plurality of terminal apparatuses of a high-speed mobile unit has an advantage of overcoming the propagation loss that may occur when a radio wave received from the outside of a high-speed mobile unit passes through a high-speed mobile unit during direct communication between the user terminal and the base station . In addition, this method can reduce the overhead that can be caused by simultaneous handover of a large number of user terminals aboard a high-speed mobile terminal by performing a group handover by a high-speed mobile terminal at a cell boundary.

In the case of a high-speed moving body, since the length of the vehicle body is relatively long and is composed of a plurality of carriages, a large number of antennas can be installed outside the high-speed moving body, and the spacing between the antennas can be relatively large. However, a plurality of terminal devices respectively connected to the plurality of antennas independently communicate with the base station, and various information including channel information is transmitted to the base station in order to perform operations such as beam search for beam forming, change of transmission method, do. Such a structure may result in waste of radio resources due to unnecessary procedures between a plurality of terminal apparatuses and a base station and redundant feedback information transmission through an uplink / downlink control channel. If the high-speed mobile apparatus moves at a low speed, The performance can be seriously degraded because it can not adapt to the fast rate of change of the channel due to the slow processing time of each terminal and the base station when moving at high speed. Therefore, by utilizing the feature that the high-speed mobile unit moves along a fixed line differently from the terminal in the general cellular environment, it can effectively communicate with the base station by adapting to a fast channel change occurring in high- Or unnecessary procedures, and a way to reduce feedback information.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mobile wireless backhaul network capable of effectively communicating with a base station by adapting to a fast channel change occurring during a high-speed mobile movement in a mobile wireless backhaul network and capable of reducing redundant or unnecessary procedures and feedback information between a plurality of antennas and a base station And to provide a communication apparatus and method in a wireless backhaul network.

According to an embodiment of the present invention, there is provided a communication method of a high-speed mobile terminal including a plurality of TEs (Terminal Equipment) connected to a plurality of antennas installed outside a high-speed mobile body in a mobile wireless backhaul network, / RTI > The communication method includes setting each TE as a secondary TE, setting a TE immediately preceding the moving direction of the high-speed moving object as a primary TE of each TE set as a secondary TE, setting each TE as a secondary TE Calculating a delay time with the primary TE and calculating a similarity between the channel estimation value measured by the TE set to the primary TE and the channel estimation value measured with the TE set to the secondary TE after the delay time satisfies the set range , Transmitting only the channel state information measured in the primary TE to the base station together with the delay time information with the corresponding primary TE among the channel state information directly measured by the TE set in the secondary TE .

The communication method may further include the step of feeding back the channel state information directly measured by the TE set in the secondary TE to the base station if the similarity does not satisfy the set range.

The channel state information fed back to the base station by the TE set as the primary TE of the TE that has transmitted the delay time information ahead of the delay time can be used for adaptive communication with the TE that has transmitted the delay time information at the base station .

Wherein the calculating the delay time comprises: measuring a channel estimate value from an auxiliary pilot signal received from the base station in each of the plurality of TEs; and estimating a channel estimate value for each TE set by the secondary TE, And calculating the delay time between each TE set to the secondary TE and the corresponding primary TE using the estimated value.

The auxiliary pilot signal may be allocated to one frequency resource element on the frequency axis and continuously allocated on the time axis.

One frame includes a plurality of subframes, and the auxiliary pilot signal can be received at a period of a subframe.

The auxiliary pilot signal may be allocated to different frequency resource elements in a period of a subframe.

The communication method comprising the steps of: setting a first TE among the plurality of TEs as a master TE of the remaining TEs based on a moving direction of the fast moving object; and setting a TE set as the master TE to transmit the measurement information for handover to the base station And feedback the channel state information.

Wherein the communication method comprises the steps of: acquiring TA information through a random access procedure in a step of performing a handover at a first location of the master TE; and, after the remaining TEs perform handover at the first location, And communicating with the base station using the TA information acquired by the master base station without a procedure.

Wherein the communication method is adapted to adaptively communicate with the base station using the channel state information measured by the TE set in the primary TE by the TE set by the secondary TE when the degree of similarity satisfies the set range, The channel state information measured by the TE set to the primary TE ahead of the delay time is updated based on the channel state information transmitted in the TE set in the secondary TE so as to be adjacent to the TE set in the secondary TE And can be used for adaptive communication with the TE located immediately behind.

Wherein one frame includes a plurality of subframes, one subframe includes a plurality of slots, and the step of calculating the delay time comprises calculating a delay time of each of the plurality of subframes calculated in the TE set as the secondary TE Extracting time information in which a channel estimation value that is most similar to the channel estimation value calculated in the TE set to the primary TE is detected for each slot among the channel estimation values;

And calculating the delay time based on the time information calculated for each slot during the search calculation interval.

The search calculation interval may be determined according to an interval between an antenna connected to the primary TE and an antenna connected to the secondary TE and a speed of the high-speed mobile.

According to another embodiment of the present invention, there is provided a high-speed mobile terminal installed in a high-speed mobile body moving along a fixed path. The high-speed mobile terminal includes a plurality of antennas, a plurality of TEs (Terminal Equipment), and a central processing unit. A plurality of antennas are installed at predetermined intervals in the high-speed mobile body. The plurality of TEs are connected to the plurality of antennas, respectively, and measure a channel estimation value from an auxiliary pilot signal received through the plurality of antennas from the base station. The central processing unit calculates a delay time between a first TE specified by the primary TE and a second TE specified by the secondary TE, based on the channel estimation values measured by the plurality of TEs. If the similarity between the channel estimation value measured by the first TE and the channel estimation value measured by the second TE after the delay time satisfies the allowable range, And transmits only the channel state information and the channel state information measured in the first TE to the base station together with the calculated delay time information, and if the similarity does not satisfy the allowed range, Feedback to the base station.

Channel state information fed back to the Node B by the first TE ahead of the delay time is used for adaptive communication with the second TE and channel state information fed back by the first TE to the Node B by the delay time And the updated channel state information is updated based on the direction of movement of the fast moving object at the base station by adaptive communication with a third TE located immediately adjacent to the second TE Lt; / RTI >

The TE based on the moving direction of the high-speed moving object is set as the secondary TE, the preceding TE is set as the primary TE, and the TE among the plurality of TEs is set as the primary TE, Can be set as master TE.

The TE set as the master TE feeds back the measurement information for handover to the base station and obtains the TA information through the random access procedure in performing the handover at the first location, And perform uplink transmission using the TA information acquired by the master base station without the random access procedure.

One frame includes a plurality of subframes, one subframe includes a plurality of slots, and the central processing unit calculates, for each of the slots, the channel estimation values calculated in the second TE during the set search calculation interval, And a delay time calculator for calculating the delay time on the basis of the time information calculated for each slot during the search calculation interval by extracting time information in which a channel estimation value most similar to the channel estimation value calculated in the first TE is detected for each slot, can do.

The search calculation interval may be determined according to an interval between an antenna connected to the first TE and an antenna connected to the first TE and a speed of the fast moving vehicle.

The auxiliary pilot signal may be allocated to one frequency resource element on the frequency axis and continuously allocated on the time axis.

One frame includes a plurality of subframes, and the auxiliary pilot signal is received at a period of a subframe, and may be allocated to different frequency resource elements at a period of the subframe.

According to the embodiment of the present invention, by calculating the time difference between the antennas installed outside the high-speed mobile body by utilizing the feature that the high-speed mobile body composed of the plurality of terminal devices communicating with the base station independently move along the fixed line, It is possible to effectively communicate with the base station by adapting to the fast channel change due to the movement speed, to perform unnecessary procedures for performing operations such as beam search for beamforming, change of transmission method, and handover, .

1 is a diagram illustrating an example of a mobile wireless backhaul network for a high-speed mobile station according to an embodiment of the present invention.
2 is a diagram illustrating a portion of a high-speed mobile terminal according to an embodiment of the present invention.
3 is a diagram illustrating a high-speed mobile terminal according to an embodiment of the present invention.
4 is a diagram illustrating an example of a delay time between P-TE and S-TE according to an embodiment of the present invention.
5 and 6 are diagrams illustrating auxiliary pilot signals according to an embodiment of the present invention, respectively.
7 is a diagram illustrating a method of calculating a delay time between P-TE and S-TE according to an 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 and claims, when a section is referred to as "including " an element, it is understood that it does not exclude other elements, but may include other elements, unless specifically stated otherwise.

Throughout the specification, a terminal is referred to as a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR- A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE) , HR-MS, SS, PSS, AT, UE, and the like.

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station (HR) A femto BS, a home Node B, a HNB, a pico BS, a metro BS, a micro BS, ), Etc., and all or all of ABS, Node B, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR- And may include negative functionality.

Now, a high-speed mobile terminal and a communication method in a mobile wireless backhaul network according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating an example of a mobile wireless backhaul network for a high-speed mobile terminal according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a portion of a high-speed mobile terminal according to an embodiment of the present invention.

Referring to FIG. 1, a mobile wireless backhaul network 10 for a high-speed mobile includes a base station and a high-speed mobile terminal. Here, the high-speed mobile means a transportation means moving along a fixed route such as a high-speed rail, a general train, and a subway.

2, the high-speed mobile terminal 200 includes a plurality of antennas (Ant # 1 to Ant # n) and a plurality of terminal equipment (hereinafter referred to as "TE") 210 ₁ to 210 _n .

The plurality of TEs 210 ₁ to 210 _n are connected to a plurality of antennas (Ant # 1 to Ant # n), respectively, and independently communicate with the base station. The plurality of antennas (Ant # 1 to Ant # n) may be distributedly installed at intervals set outside the high-speed mobile body.

Each of the TEs 210 ₁ to 210 _n of the high-speed mobile terminal 200 performs a mobile wireless backhaul communication between the user terminal and the base station in order to provide services to the user terminal in the high-speed mobile terminal. That is, each of the TEs 210 ₁ to 210 _n of the high-speed mobile terminal 200 transmits the data received from the base station through the antennas Ant # 1 to Ant # n to the user terminal, To the base station through the antennas Ant # 1 to Ant # n. Each of the TEs 210 ₁ to 210 _n of the high-speed mobile terminal 200 includes at least one small cell base station or at least one Wi-Fi access point (AP) And can transmit / receive data to / from user terminals in a high-speed mobile unit through a small cell base station or a Wi-Fi AP.

Referring again to FIG. 1, a base station includes a digital unit (DU) 110 and a plurality of radio units (RUs) 120 _i and 120 _{i + 1} . In FIG. 1, only two RUs (120 _i , 120 _{i + 1} ) connected to one DU 110 are shown.

The DU 110 of the base station is connected to a plurality of RUs 120 _i and 120 _{i + 1} and is connected to the core network through a gateway GW.

The plurality of RUs 120 _i and 120 _{i + 1} include at least one antenna, and may be installed along a path through which the high-speed mobile unit moves.

Such a base station can transmit and receive data to and from a high-speed mobile terminal using a millimeter-wave frequency band.

As described above, in the mobile radio backhaul network 10 for a high-speed mobile, a plurality of TEs 210 ₁ to 210 _n independently communicate with the base station. Therefore, the plurality of TEs 210 ₁ to 210 _n independently perform beam searching, beamforming, and handover for beamforming communication with the base station. Therefore, an unnecessary procedure between the TEs 210 ₁ to 210 _n and the base station And redundant feedback information transmission through the uplink / downlink control channel may cause radio resource waste.

Also, since the coherence time of the wireless channel is very short due to the fast moving speed of the high-speed mobile body, the channel changes very rapidly on the time axis. However, in general, the TEs 210 ₁ to 210 _n of the high-speed mobile terminal 200 measure the channel status information through the pilot signal received from the base station and report the measurement result to the base station. At this time, a processing delay time may occur. In addition, the mobile radio backhaul, which must support large amounts of wireless backhaul data, may not be able to adaptively communicate with the fast change of the channel due to the high moving speed because the processing delay may be longer.

In other words, in the case of frequency division duplex (FDD), the channel at the time of measurement by the TEs 210 ₁ to 210 _n and the channel at the time of the base station attempting to communicate based on the measurement result of the UE may have changed greatly, The performance may seriously deteriorate when the base station performs beamforming, transmission mode change, handover, etc. based on the measurement result of the terminal. Even in the case of TDD (Time Division Duplex), even if the BS measures the uplink channel and uses it for downlink transmission, there is still a processing delay and the period of the UL subframe is also very long.

However, the mobile wireless backhaul network 10 for a high-speed mobile has characteristics different from the general cellular environment. Since the high-speed moving object moves along the fixed path, the TE 210 ₁ passes through the TE 210 _{2 as} shown in FIG. ₁ , and the TE 210 ₁ and TE 210 ₂ ) Will be very similar. Therefore, in the embodiment of the present invention, a method of solving the above-mentioned problem is proposed by utilizing a feature that a plurality of TEs 210 ₁ to 210 _n installed on a high-speed mobile body undergoes a very similar wireless channel at a constant time interval .

First, in the embodiment of the present invention, the roles of the TEs 210 ₁ to 210 _n are defined. That is, each of the TEs 210 ₁ to 210 _n operates as a master TE (hereinafter referred to as "M-TE") or as a primary TE (hereinafter referred to as "P-TE" Or a secondary TE (hereinafter referred to as "S-TE") is designated by the base station. Here, P-TE and S-TE are relative concepts. 2, in the case of the TE 210 ₁ and TE 210 ₂ , the TE 210 ₁ is the P-TE of the TE 210 ₂ and the TE 210 ₂ is the P-TE of the TE 210 ₂ , _2), but the S-TE, when the TE (210 ₂₎ and _{TE (210 3) TE (210} 2) is a P-TE for _{TE (210 3) TE (210} 3) is the S-TE . And the TE (210 ₁ ) at the front of the high-speed mobile is M-TE. That is, the TE 210 ₁ is the M-TE of the remaining TEs 210 ₂ to 210 _n and the P-TE of the TE 210 ₂ . And the TE 210 _n at the rear of the high-speed mobile does not have S-TE.

The base station designates M-TE, P-TE, and S-TE for each of the TEs 210 ₁ to 210 _n and notifies the high-speed mobile terminal 200 thereof. If the high-speed mobile unit is traveling in one direction, M-TE, P-TE, and S-TE can be fixed for each TE (210 ₁ to 210 _n ). However, since there are high-speed mobile stations operating in both directions, the base station can determine the direction of movement of the high-speed mobile and specify M-TE, P-TE and S-TE for each TE through the downlink control channel.

3 is a diagram illustrating a high-speed mobile terminal according to an embodiment of the present invention.

3, the high-speed mobile terminal 200 includes a plurality of antennas Ant # 1 to Ant # n, a plurality of TEs 210 ₁ to 210 _n , and a central processing unit 220.

The TEs 210 ₁ to 210 _n may include baseband processors 212 ₁ to 212 _n and upper layer processors 214 ₁ to 214 _n , respectively.

Each of the plurality of antennas Ant # 1 to Ant # n receives the downlink signal from the base station and transmits the downlink signal to the corresponding baseband processing unit 212 of the TE. The plurality of antennas (Ant # 1 to Ant # n) transmit the uplink signals transmitted from the corresponding baseband processor 212 of the TE to the base station.

The plurality of baseband processing units 212 ₁ to 212 _n process the downlink signals transmitted from the corresponding antennas Ant # 1 to Ant # n, process the uplink signals, Ant # n). The baseband processing units 212 ₁ to 212 _n may perform physical layer functions such as modulation, demodulation, coding, decoding, and channel estimation. In particular, each of the baseband processing units 212 ₁ to 212 _n estimates a channel using the auxiliary pilot signal received from the base station via the corresponding antenna, and continuously outputs the channel estimation value to the delay time calculation unit 222, and stores the channel estimation value between the antenna and the base station in the storage unit 226 of the central processing unit 220. At this time, the auxiliary pilot signal is used to measure the delay time between the antennas connected to the P-TE and the S-TE, respectively, as described later. The baseband processing units 212 ₁ to 212 _n measure channel state information (CSI) using the basic pilot signal received from the base station through the respective antennas, and transmit the measured CSI to the central processing unit 220, In the storage unit 226 of the display unit. The CSI may be measured using an auxiliary pilot signal. The CSI includes a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indication, a signal to noise ratio (SNR), a signal to interference and noise ratio (SINR), a carrier to interference ratio (CIR) Carrier to Interference and Noise Ratio (RSRP), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and the like. The CSI may also include the CSI of the serving cell and the target cell. The CSI of the serving cell and the target cell may be used for handover decision.

The upper layer processing units 214 ₁ to 214 _n perform an upper layer function using the CSI and the handover related information stored in the storage unit 226. The handover related information may include measurement information for handover determination and information necessary for handover. The upper layer function may mean an upper layer function of a physical layer such as a Medium Access Control (MAC) layer or an RLC (Radio Link Control) layer. For example, a beamforming determination, a transmission method determination, .

An upper layer processing unit (214 ₁ ~ 214 _n) from the upper layer processing for the master TE (214 ₁₎ is a feed back the measured information to the antenna and the base station between the CSI and the handover based on the control of the controller 224 to the base station do. The upper layer processing units 214 ₂ to 214 _n corresponding to the remaining TEs except for the master TE among the upper layer processing units 214 ₁ to 214 _n are controlled by the control unit 224 to perform CSI and handover determination It is possible to omit the feedback process of the measurement information for the measurement information. That is, the upper layer processing units 214 ₂ to 214 _n corresponding to the secondary TE do not feed back the CSI and the measurement information for handover decision but calculate the calculated time with their P-TE calculated by the delay time calculation unit 222 (Hereinafter referred to as "delay time") information to the base station.

In addition, the upper layer processing units 214 ₂ to 214 _n corresponding to the remaining TEs except the master TE may omit some procedures for communication with the base station under the control of the control unit 224.

The central processing unit 220 may include a delay time calculation section 222, a control section 224, and a storage section 226.

The delay time calculation unit 222 calculates a delay time between the P-TE and the S-TE based on the channel estimation value received from each of the TEs 210 ₁ to 210 _n . The delay time between P-TE and S-TE may mean the delay time between antennas connected to P-TE and S-TE, respectively.

When the delay time between the P-TE and the S-TE is calculated by the delay time calculation unit 222, the delay time between the P-TE and the S-TE calculated for each TE is stored in the storage unit 226.

The control unit 224 controls overall functions for the plurality of TEs 210 ₁ to 210 _n in the high-speed mobile unit to communicate with the base station. The control unit 224 controls the TEs 210 ₁ to 210 _n and the delay time calculation unit 222 in the high speed mobile terminal 200 and requests the base station to transmit the auxiliary pilot signal. The control unit 224 determines whether or not to feedback the CSI between the corresponding antenna and the base station in the TE specified by the S-TE, and may decide to omit some procedures from the procedure for communicating with the base station.

The storage unit 226 stores and manages CSI information and handover related information between each antenna and the base station, measured by the TEs 210 ₁ to 210 _n .

A communication method according to an embodiment of the present invention will now be described in detail with reference to FIG.

4 is a diagram illustrating an example of a delay time between P-TE and S-TE according to an embodiment of the present invention.

Referring to FIG. 4, one frame is composed of 40 slots (# 0 to # 39), and one subframe is composed of 8 slots.

TE 210 ₂ is S-TE, and TE 210 ₁ is P-TE of TE 210 ₂ . The TE (210 ₁₎ The No. 10 three times slot # 3, the channel estimation value measured at a time point of the measurement at the time when the channel estimation value and the TE (210 ₂₎ a 15 0 slot of the frame # 0 of the frame , The delay time between the TEs 210 ₁ and 210 ₂ can be calculated to be about 203 (= 40 5 + 3) slots.

Then, the controller 224 is 15 TE (210 ₂₎ is to determine that it does not feed back the measured CSI at the point of 15 0 slot of the frame (# 0) to the base station accordingly TE (210 ₂₎ Frame The CSI measured at the time of the 0th slot (# 0) of the TE (210 ₁ , 210 ₂ ) is not fed back to the base station, and the calculated delay time information is transmitted to the base station. Based on the delay time information received from the TE 210 ₂ , the base station adaptively communicates with the TE 210 ₂ based on information such as CSI fed back by the TE 210 ₁ ahead of 203 slots. Since the base station adaptively communicates with the TE 210 ₂ based on information such as the CSI fed back from the TE 210 ₁ , the TE 210 ₂ also receives the CSI measured by the TE 210 ₁ The base station can adaptively communicate with the base station.

In this case, TE (210 ₂₎ is an even if satisfying the range of the set similarity of channel estimation values with their in _{TE (210 1) P-TE} , the directly measured CSI measured in TE (210 ₁₎ CSI and other parts If so, then everyone can feed back information about the part to the base station. For example, TE (210 ₂₎ the CSI is "CQI index = 7, RI = 1" and, TE (210 ₂₎ of the P-TE in TE (210 ₁₎ is TE, which feedback to the base station stores measurement in If the CSI of the (210 ₁₎ assumed to be "CQI index = 7, RI = 2", TE (210 2) is changed RI value for the TE (210 ₃₎ it is set to TE (210 ₂₎ to the P-TE ( RI = 1) to the base station, and the base station updates the CSI of the TE 210 ₂ to "CQI index = 7, RI = 1". The base station uses the CSI of "CQI index = 7, RI = 1" when communicating with the TE 210 ₃ .

The base station can communicate very quickly to adapt to channel changes by not receiving the CSI from the TE 210 ₂ or only receiving some changed information, and the TE 210 ₂ can reduce unnecessary feedback procedures with the base station have.

Then, the TE 210 ₂ becomes a P-TE of the next TE 210 _{3 in terms} of time. Therefore, TE (210 ₂₎ is by feeding their when P-TE in TE (210 ₁₎ does not satisfy the range is set the higher the similarity between the channel estimation value, CSI directly measured for the next TE (210 ₃₎ to the base station , So that the base station can update the CSI of the TE 210 ₂ . This allows more accurate feedback information to be applied to the next TEs. Here, the range may be set to a range where the channel estimation values measured by the P-TE and the S-TE, respectively, at the same point can be judged to be similar, and the value of the range may be changed. Also, when handover is determined based on measurement information for handover reported from a TE (for example, 210 ₁ ) designated as a P-TE while being an M-TE at a specific point, 210 ₁ performs handover, and performs a random access procedure in a handover execution step to obtain TA (Timing Advance) information. The TE 210 ₁ transmits the acquired TA information to the central processing unit 220 in the high-speed mobile terminal 200. The control unit 224 by giving a rest TE (210 ₂ ~ 210 _n) specified in the TA information to the S-TE known in advance, and the other TE (210 ₂ ~ 210 _n) other than the M-TE's central processing unit 220, respectively It is possible to omit the reporting of the measurement information for the handover and the random access procedure based on the delay time between the P-TEs themselves. The TE 210 ₁ stores information necessary for handover to and from the base station in the storage unit 226 so that the remaining TEs 210 ₂ to 210 _n can utilize information necessary for handover. By doing so, the unnecessary feedback information related to the handover can be reduced, the related procedure including the random access procedure can be simplified, and the remaining TEs 210 ₂ to 210 _n except the M-TE can be handled without any interruption It is possible to perform handover with almost no break. Also, the mobile wireless backhaul link of the TE 210 ₂ to 210 _n and the base station is disconnected due to the handover, so that a very lethal disadvantage that the connection of a plurality of user terminals inside the high-speed mobile unit is temporarily interrupted can be compensated.

5 and 6 are diagrams illustrating auxiliary pilot signals according to an embodiment of the present invention, respectively.

As described above, an auxiliary pilot signal is used to calculate the delay time between P-TE and S-TE.

As shown in FIG. 5, the auxiliary pilot signals P ₀ , P ₁ , ..., and P ₁₁ are continuously allocated on the time axis, and all frequency resource blocks (RB # 1 to RB #N). ≪ / RTI > One RB is composed of a plurality of frequency resource elements RE and a plurality of time symbols, and the auxiliary pilot signals P ₀ , P ₁ , ..., P ₁₁ are, for example, RE, for example, can be consecutively allocated to the 12th RE on the time axis.

These auxiliary pilot signals (P ₀ , P ₁ , ..., P ₁₁ ) are used to measure the delay time between P-TE and S-TE and can serve as an auxiliary in channel estimation for demodulation.

Then, the basic pilot signals of the antenna # 1 and the antenna # 2 of the RU are allocated to predetermined resource positions, and the basic pilot signals of the antenna # 1 and the antenna # 2 of the RU can be used for the CSI measurement.

Whether or not the auxiliary pilot signals P ₀ , P ₁ , ..., P ₁₁ are transmitted is determined by the control unit 224 of the central processing unit 220 of the high-speed mobile terminal 200 and transmitted to each of the TEs 210 ₂ to 210 _n And may be requested to the base station via the connected antennas Ant # 1 to Ant # n.

It is not necessary that the auxiliary pilot signals (P ₀ , P ₁ , ..., P ₁₁ ) are continuously transmitted after a certain accurate delay time between P-TE and S-TE is calculated and stabilized.

6, the base station only transmits the auxiliary pilot signals P ₀ , P ₁ , ..., P ₁₁ at the control unit 224 of the central processing unit 220 to the subframe period (P ₀ , P ₁ , ..., P ₁₁ ) during some or all of the slots in the subframe. At this time, the position of the frequency RE of the auxiliary pilot signals (P ₀ , P ₁ , ..., P ₁₁ ) can be changed. For example, in any subframe, the auxiliary pilot signals P ₀ , P ₁ , ..., P ₁₁ are allocated to the 12th RE of RB # K, and auxiliary pilot signals P ₀ , P ₁ , , P ₁₁ ) may be allocated to the third RE of RB # L.

P-TE and S-TE receive the auxiliary pilot signals (P ₀ , P ₁ , ..., P ₁₁ ) to measure the channel estimation values, and based on the channel estimation values measured by P-TE and S- -The delay time between TE and S-TE is calculated. The delay time calculation method between P-TE and S-TE has a restriction condition that the channel should not change within a symbol interval on the time axis. However, in general, even if a fast moving object moves at a high speed, It is not a big problem because there is little work.

7 is a diagram illustrating a method of calculating a delay time between P-TE and S-TE according to an embodiment of the present invention.

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,

](p=0,1, …, N_p-1)을 측정한다(S710). 여기서, N_p는 슬롯 내 보조 파일롯 심볼의 개수이고,

는 P-TE로 지정된 TE가 n번째 슬롯의 p번째 보조 파일롯 심볼을 이용하여 측정한 채널 추정값을 나타내며,

는 S-TE로 지정된 TE가 n번째 슬롯의 p번째 보조 파일롯 심볼을 이용하여 측정한 채널 추정값을 나타낸다. Referring to FIG. 7, the TE 210 ₁ to 210 _n transmit the auxiliary pilot signal [ _N ] in each slot of the subframe in each of the baseband processing units 212 ₁ to 212 _n ,

], The channel estimation value [

,

] (p = 0, 1, ..., N _p -1) (S710). Where N _p is the number of auxiliary pilot symbols in the slot,

Denotes a channel estimation value measured by a TE specified by P-TE using the p-th auxiliary pilot symbol of the n-th slot,

Represents a channel estimation value measured by the TE designated S-TE using the p-th auxiliary pilot symbol of the n-th slot.

The TEs 210 ₁ to 210 _n transmit the measured channel estimation values and corresponding time information to the delay time calculator 222 of the central processing unit 220. The time information may include at least one of a frame number, a subframe number, and a slot number in which a channel estimation value is calculated.

The delay time calculation unit 222 of the central processing unit 220 calculates the delay time of each TE 210 (210 ₁ to 210 _n ) designated as S-TE based on the similarity degree of the channel estimation value with P-TE for each TE ₁ to 210 _n ), the delay time between the P-TE and the S-TE is calculated (S720). For example, the delay time calculation unit 222 calculates necessary parameter values for a predetermined search interval using Equation (1) for each TE (210 ₁ to 210 _n ) designated as S-TE, -TE can be calculated.

을 찾아내고,

개의 슬롯에서 각각 구해진

의 평균값인 지연시간 τ_mean을 계산한 후, 최종적으로는 지연시간 n_mean을 계산할 수 있다. 여기서, τ_mean은 심볼 개수를 나타낸 지연시간이며, n_mean은 슬롯 개수로 나타낸 지연시간이다.The delay time calculator 222 of the central processing unit 220 calculates the minimum D (n, τ) value, that is, the minimum value D (n, τ), through the iterative calculation during the search calculation interval set in each slot of the sub-

≪ / RTI >

Lt; RTI ID = 0.0 >

The delay time τ _mean , which is an average value of the delay time τ _mean , and finally the delay time n _mean . Here, τ _mean is a delay time representing the number of symbols, and n _mean is a delay time expressed by the number of slots.

In Equation (1), N _sum may be determined according to the processing capability of the central processing unit 220 of the high-speed mobile terminal 200. The larger the N _sum , the higher processing performance is required, while a more accurate delay time measurement becomes possible. D (n, τ) is an index indicating the degree of similarity between channels in the nth slot of the TE specified by P-TE and the channel after delay time by τ in the nth slot of the TE specified by S-TE. Here, τ has a symbol unit. That is, the larger the value of D (n, τ), the greater the difference between the channel in the nth slot of the TE specified by P-TE and the channel after delay time by τ in the nth slot of the TE specified by S-TE . Conversely, the smaller the D (n, τ) value, the smaller the difference between the channel in the nth slot of the TE specified by P-TE and the channel after delay time by τ in the nth slot of TE specified by S-TE do. T _search represents the search calculation interval and is determined by the antenna installation interval connected to P-TE and S-TE and the speed of high-speed mobile unit. T _search is shorter as the speed of a high-speed moving object is fast or the interval between antennas connected to P-TE and S-TE is narrow, the speed of a high-speed moving object is slow or the interval between antennas connected to P-TE and S- The longer it gets. T _search decision related to a simple example is that of the high-speed moving object speed 400km / h and P-TE and the S-P TE-TE approximately 90.09ms since if the respective associated antenna spacing is 10m to the S-TE Past the passing point. Therefore, the central processing unit 220 of the high-speed mobile terminal 200 can obtain the accurate n _mean by calculating D (n, τ) value for at least 90.09 ms, so that the T _search can be set to at least 90.09 ms.

On the other hand, when the wired network is not connected to the TE and the central processing unit 220 of the high-speed mobile terminal 200 is not provided, the channel estimation values of the TEs 210 ₁ to 210 _n can be measured at the base station. To this end, each of the TEs 210 ₁ to 210 _n sequentially allocates the auxiliary pilot signal on one frequency RE on the time axis on the uplink and transmits the auxiliary pilot signal to the base station. A plurality of TE (210 ₁ ~ 210 _n) that when transmitting a second pilot signal in the uplink, a plurality of TE (210 ₁ ~ 210 _n) is transmitted because the time resources overlap of the auxiliary pilot signal, a plurality of TE (210 ₁ To 210 _n transmit the auxiliary pilot signal to the base station continuously on a time axis using a ZC (Zadoff-Chu) sequence so that the base station can calculate the channel estimation value of each TE 210 ₁ to 210 _n . In this case, the delay time between the TEs is also calculated in the base station, and the delay time between the TEs is transmitted to the high-speed mobile terminal 200 through the downlink control channel. And all control over the TEs 210 ₁ to 210 _n can be made at the base station. When the calculation is stabilized by calculating a certain accurate value of the delay time between the TEs in the base station, the TEs 210 ₁ to 210 _n are allocated to the sub-frame 210 to reduce the resource burden on the auxiliary pilot signal as shown in FIG. To transmit the pilot pilot signal.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented by a program for realizing functions corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

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 (20)

A communication method for a high-speed mobile terminal including a plurality of TEs (Terminal Equipment) connected to a plurality of antennas installed outside a high-speed mobile body in a mobile wireless backhaul network and independently communicating with a base station,
Setting each TE as a secondary TE, setting a TE immediately preceding the moving direction of the high-speed moving object as a primary TE of each TE set as a secondary TE,
Calculating a delay time with the primary TE for each TE set as the secondary TE, and
When the similarity between the channel estimation value measured by the TE set by the primary TE and the channel estimation value measured by the TE set by the secondary TE after the delay time satisfies the set range, Transmitting only the channel state information measured in the primary TE to the base station together with the delay time information with the corresponding primary TE
/ RTI > The method of claim 1,
If the similarity does not satisfy the set range, feeding back the channel state information directly measured by the TE set in the secondary TE to the base station
Lt; / RTI > The method of claim 1,
The channel state information fed back to the base station by the TE set as the primary TE of the TE that has transmitted the delay time information ahead of the delay time is used for communication used for adaptive communication with the TE that has transmitted the delay time information at the base station Way. The method of claim 1,
The step of calculating the delay time
Measuring a channel estimate value from an auxiliary pilot signal received from the base station in each of the plurality of TEs; and
And calculating a delay time between each TE set to the secondary TE and the corresponding primary TE using the channel estimate values measured by each of the TEs set to the secondary TE and the corresponding primary TEs. 5. The method of claim 4,
Wherein the auxiliary pilot signal is allocated to one frequency resource element on a frequency axis and is continuously allocated on a time axis. The method of claim 5,
One frame includes a plurality of sub-frames,
Wherein the auxiliary pilot signal is received at a period of a subframe. The method of claim 6,
Wherein the auxiliary pilot signal is allocated to different frequency resource elements in a cycle of a subframe. The method of claim 1,
Setting a preceding TE as the master TE of the remaining TEs based on the moving direction of the fast moving body among the plurality of TEs, and
The TE set as the master TE returns measurement information and channel state information for handover to the base station
Lt; / RTI > 9. The method of claim 8,
Obtaining the TA information through the random access procedure in the step of the handover of the master TE at the first location, and
After the remaining TEs perform handover at the first location, communicating with the base station using the TA information acquired by the master base station without the random access procedure
Lt; / RTI > The method of claim 1,
When the similarity degree satisfies the set range, adaptively communicating with the base station using the channel state information measured by the TE set in the primary TE by the TE set in the secondary TE ahead of the delay time
Further comprising:
The channel state information measured by the TE set to the primary TE ahead of the delay time is updated based on the channel state information transmitted from the TE set to the secondary TE so that the adaptation to the TE located immediately adjacent to the TE set as the secondary TE A communication method used for communication. The method of claim 1,
One frame includes a plurality of subframes, one subframe includes a plurality of slots,
The step of calculating the delay time
Time information in which a channel estimation value that is most similar to the channel estimation value calculated in the TE set to the primary TE for each slot among the channel estimation values calculated in the TE set to the secondary TE is detected for each slot during the set search calculation interval Step, and
And calculating the delay time based on the time information calculated for each slot during the search calculation interval. 12. The method of claim 11,
Wherein the search calculation interval is determined according to an interval between an antenna connected to the primary TE and an antenna connected to the secondary TE and a speed of the high-speed mobile. A high-speed mobile terminal installed in a high-speed mobile body moving along a fixed path,
A plurality of antennas arranged at predetermined intervals in the high-speed mobile body,
A plurality of TEs (Terminal Equipment) connected to the plurality of antennas for measuring a channel estimation value from an auxiliary pilot signal received through the plurality of antennas from the base station,
A central processing unit for calculating a delay time between a first TE specified as a primary TE and a second TE specified as a secondary TE among the plurality of TEs based on channel estimation values measured by the plurality of TEs,
Lt; / RTI >
If the similarity between the channel estimation value measured by the first TE and the channel estimation value measured by the second TE after the delay time satisfies an allowable range, 1 < / RTI > TE and other channel state information together with information of the calculated delay time to the base station, and if the similarity does not satisfy the allowed range, Speed mobile terminal. The method of claim 13,
Channel state information fed back by the first TE to the base station ahead of the delay time is used for adaptive communication with the second TE,
The channel state information fed back by the first TE to the base station ahead of the delay time is updated on the basis of the channel state information transmitted from the second TE, and the updated channel state information indicates the direction of movement of the high- And is adapted for adaptive communication with a third TE located immediately adjacent to and adjacent to the second TE. The method of claim 13,
The TE based on the moving direction of the high-speed moving object is set as the secondary TE, the preceding TE is set as the primary TE, and the TE among the plurality of TEs is set as the primary TE, A high-speed mobile terminal set as a master TE. 16. The method of claim 15,
The TE set as the master TE feeds back the measurement information for handover to the base station and obtains the TA information through the random access procedure in the handover performed at the first location,
Wherein the remaining TEs carry out uplink transmission using the TA information acquired by the master base station without performing the random access procedure after performing handover at the first location. The method of claim 13,
One frame includes a plurality of subframes, one subframe includes a plurality of slots,
The central processing unit extracts time information in which a channel estimation value most similar to the channel estimation value calculated in the first TE is detected for each slot among the channel estimation values calculated in the second TE for each slot during a set search calculation period And a delay time calculator for calculating the delay time based on the time information calculated for each slot during the search calculation interval. The method of claim 17,
Wherein the search calculation interval is determined according to an interval between an antenna connected to the first TE and an antenna connected to the first TE and a speed of the fast moving vehicle. The method of claim 13,
Wherein the auxiliary pilot signal is allocated to one frequency resource element on a frequency axis and is continuously allocated on a time axis. The method of claim 13,
One frame includes a plurality of sub-frames,
Wherein the auxiliary pilot signal is received at a period of a subframe and allocated to different frequency resource elements at a cycle of the subframe.

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