KR20160019057A - Method and apparatus for controlling base station - Google Patents

Method and apparatus for controlling base station Download PDF

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Publication number
KR20160019057A
KR20160019057A KR1020150110763A KR20150110763A KR20160019057A KR 20160019057 A KR20160019057 A KR 20160019057A KR 1020150110763 A KR1020150110763 A KR 1020150110763A KR 20150110763 A KR20150110763 A KR 20150110763A KR 20160019057 A KR20160019057 A KR 20160019057A
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KR
South Korea
Prior art keywords
base station
base stations
delay time
group mobile
signal
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KR1020150110763A
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Korean (ko)
Inventor
정희상
김일규
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한국전자통신연구원
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Application filed by 한국전자통신연구원 filed Critical 한국전자통신연구원
Priority to US14/820,164 priority Critical patent/US20160044623A1/en
Publication of KR20160019057A publication Critical patent/KR20160019057A/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/08—Testing, supervising or monitoring using real traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H04B17/364—Delay profiles
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/02—Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
    • H04W36/023—Buffering or recovering information during reselection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/12—Access point controller devices

Abstract

Determining a frame offset for a plurality of base stations based on a first delay time occurring between a group mobile unit and a plurality of base stations and a second delay time occurring between a plurality of base stations and a base station control apparatus, There is provided a base station control method and apparatus for a plurality of base stations arranged along a moving path of a group mobile station, the mobile base station including a step of transmitting data to be transmitted to a plurality of base stations based on a frame offset.

Description

[0001] The present invention relates to a method and apparatus for controlling base stations,

The present invention relates to a method and apparatus for controlling a base station arranged along a movement path of a group mobile body.

A user in a group moving at a high speed, such as a train or a bus, can access the Internet in two ways. The first method is a method in which a user in a group moving body directly connects to a base station outside the group moving body. The user can be connected directly to a base station of a mobile communication network such as a 3G (3 rd generation, 3G) or Long Term Evolution (long term evolution, LTE) even in the mobile group. A method in which a user directly connects to a base station is referred to as a one-rank system. The second method is a method in which a user connects to a base station outside the group mobile terminal via an access point (AP) in a group mobile entity. In this case, the user can use a wireless fidelity (Wi-Fi) or femto cell AP. A method in which a user indirectly accesses a base station using an AP in a group mobile is referred to as a two-rank system.

A user who has boarded a bus, a subway train or a high-speed railway in the system 1 directly connects to a mobile communication base station. In a base station, a user included in a group mobile station is not distinguished from a general user. Therefore, some problems may occur when a passenger boarding a group moving body moving at high speed is provided with a data service through the 1-rank system. First, since the data transmission rate of a mobile communication service increases as the user's mobility increases, the data transmission rate may be lowered due to high mobility of the user included in the group mobile unit. Also, since the group mobile includes dozens to hundreds of users, the data transmission rate may be further degraded due to competitive access to the cellular network. Also, a problem may occur in the base station handover of the user. Generally, a cell radius of a cellular network is within a few kilometers of a suburban area within a distance of 1 km. However, when a plurality of users included in a group mobile terminal simultaneously cross a cell boundary, a large number of handover occur simultaneously and the probability of a handover failure increases. Accordingly, when the user of the group mobile terminal uses the 1-rank system, the data transmission rate may decrease and the probability of handover failure may increase.

In a two-level system, a base station outside a group mobile entity recognizes an AP included in a group mobile entity as a single user. At this time, the wireless section formed between the base station and the APs included in the group moving body is referred to as a 'wireless backhaul'. In this case, the wireless backhaul between the group mobile station and the base station is referred to as a 'mobile wireless backhaul' in contrast to the fixed backhaul in order to emphasize the mobility of the group mobile. Since the data service for the users included in the group moving body is provided through the AP of the group moving body, the problem of the one moving system can be solved by improving the performance of the mobile wireless backhaul. That is, if the data transfer rate of the mobile wireless backhaul is increased and the success rate of the handover in the mobile wireless backhaul is increased during the high-speed movement of the group mobile unit, the users included in the group mobile unit can share the data service guaranteed by the mobile wireless backhaul .

The mobile wireless backhaul section of the two-level system includes communication between the group mobile and the satellite or communication between the group mobile and the cellular base station. Both of the two types of communication can provide a downlink download speed of about 10-20 Mbps to a user included in the group mobile terminal. In addition, millimeter-wave frequencies used for fixed backhaul are being applied to mobile wireless backhaul.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for controlling a base station for facilitating a handover of a group mobile station by simplifying a handover procedure between base stations of a group mobile station in a two mobile system of group mobile stations.

According to an embodiment of the present invention, there is provided a base station control method of a base station control apparatus for controlling a plurality of base stations disposed along a movement path of a group mobile body. The base station control method includes the steps of determining a frame offset for a plurality of base stations based on a first delay time generated between a group mobile terminal and a plurality of base stations and a second delay time generated between a plurality of base stations and a base station controller And transmitting data to be transmitted to the group moving object to a plurality of base stations based on a frame offset.

Wherein the step of determining in the base station control method comprises the steps of calculating a first delay time for each of a plurality of base stations through a first distance between a group mobile unit and a plurality of base stations and a transmission speed of air signals, Calculating a second delay time for each of the plurality of base stations via a second distance between the base station control device and a signal transmission rate in the optical fiber connecting the plurality of base station and base station control devices, And determining a frame offset based on the second delay time.

The step of determining a frame offset based on the first delay time and the second delay time in the base station control method includes: determining a frame offset based on a first delay time and a second delay time, the first offset value being a sum of a first delay time and a second delay time, Determining a frame offset based on a final delay time of the remaining base stations excluding the first base station and a final delay time of the first base station among the plurality of base stations.

In the base station control method, when the movement path is a curve, the first interval between the plurality of base stations may be shorter than the second interval between the base stations arranged along the straight movement path.

The base station control method may further include a step of assigning the same cell ID to a plurality of base stations and a step of determining a signal transmission stopping point of a plurality of base stations based on an uplink signal of the group mobile terminal.

In the base station control method, the uplink signal may be a sounding signal of the group mobile station.

In the base station control method, the uplink signal may include a measurement result of a strength of a signal corresponding to data measured by a group mobile unit.

The base station control method further includes a step of assigning different cell IDs to the plurality of base stations and a step of determining a signal transmission stopping point of the plurality of base stations based on the uplink signal generated based on the cell ID in the group mobile terminal .

According to another embodiment of the present invention, there is provided a base station control apparatus for controlling a plurality of base stations disposed along a movement path of a group moving body. The base station control apparatus includes at least one processor, a memory, and a wireless communication unit, and at least one processor executes at least one program stored in a memory to control the group moving body and the plurality of base stations Determining a frame offset for a plurality of base stations based on a first delay time and a second delay time occurring between a plurality of base stations and a base station control apparatus, As shown in FIG.

The at least one processor in the base station control apparatus determines a first delay time for each of the plurality of base stations through a first distance between the group mobile body and the plurality of base stations and a transmission speed of the air- Calculating a second delay time for each of the plurality of base stations through a second distance between the plurality of base stations and the base station control device and a transmission speed of the signal in the optical fiber connecting the plurality of base stations and the base station control device And determining a frame offset based on the first delay time and the second delay time.

Wherein the at least one processor in the base station control apparatus performs a step of determining a frame offset based on the first delay time and the second delay time based on a difference between a first delay time and a second delay time, Determining a first base station having the smallest time and determining a frame offset based on a final delay time of the first base station and a final delay time of the first base station excluding the first base station among the plurality of base stations .

If the movement path in the base station control apparatus is a curve, the first interval between the plurality of base stations may be shorter than the second interval between the base stations arranged along the straight movement path.

At least one processor in the base station control apparatus executes at least one program to assign a same cell ID to a plurality of base stations and to determine a signal transmission stopping point of a plurality of base stations based on an uplink signal of the group mobile station Can be performed.

In the base station control apparatus, the uplink signal may be a sounding signal of the group mobile station.

The uplink signal in the base station control apparatus may include information on the strength of the signal corresponding to the data measured by the group moving body.

Wherein the at least one processor in the base station control apparatus executes at least one program to assign a different cell ID to a plurality of base stations, And determining a point at which the base station stops transmitting the signal.

According to another embodiment of the present invention, there is provided a data transmission method of a base station arranged along a movement path of a group mobile object. The data transmission method includes receiving a frame offset from a base station control apparatus of a base station and a neighboring base station of a base station, and transmitting data to a group mobile station based on a frame offset.

In the data transmission method, the frame offset may be calculated based on a first delay time occurring between the group mobile station and the base station and a second delay time occurring between the base station and the base station control apparatus.

In the data transmission method, when the movement path is a curve, the interval between the base station and the neighboring base station may be shorter than the interval between other base stations disposed along the straight movement path.

The data transmission method may further include receiving an uplink signal from the group mobile station, and stopping the transmission according to a signal transmission stop time point of the data determined based on the uplink signal.

According to an embodiment of the present invention, data is transmitted to a group mobile station based on a frame offset calculated based on a delay time of a signal between a group mobile station, a base station, and a base station control apparatus, And wireless communication can be performed. Also, by controlling the frame offset for the neighboring base station control apparatus, the group mobile unit can perform wireless communication by greatly simplifying the handover procedure even when entering the coverage of the base station connected to another base station control apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a group moving body moving between base stations installed on the roadside. FIG.
FIG. 2 is a diagram illustrating a group moving body moving between base stations installed in a roadside according to an embodiment of the present invention.
3 is a diagram illustrating a wireless communication system according to an embodiment of the present invention.
4A and 4B are diagrams illustrating a frame offset of a digital signal according to an exemplary embodiment of the present invention.
5, 6, and 7 are diagrams illustrating frame offsets of a straight line section according to an embodiment of the present invention.
8 is a flowchart illustrating a base station control method of a base station control apparatus according to an embodiment of the present invention.
FIG. 9 is a diagram illustrating a group moving body operating a curved section according to an embodiment of the present invention.
10 and 11 are diagrams illustrating a method of calculating a frame offset in a curve section.
12 is a diagram illustrating a wireless communication system including a plurality of base station control apparatuses according to an embodiment of the present invention.
13 is a block diagram illustrating a wireless communication system 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, a mobile station (MS) is referred to as a terminal, a mobile terminal (MT), 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 macro BS, a micro BS, ), Etc., and may be all or part of an ABS, a Node B, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, an RS, an RN, an ARS, It may include a negative feature.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a group moving body moving between base stations installed on the roadside. FIG.

Referring to FIG. 1, in a wireless communication system of a group mobile station, base stations 110 and 120 are located along a road (a road or a train line), and the group moving body 10 moves along a road or a train line. At this time, the group moving body 10 receives radio waves from all directions equally and transmits radio waves in all directions equally.

Referring to FIG. 1, the base stations 110 and 120 may form cells 131, 132, 133 and 134, respectively, before and after the base station. When the group moving body 10 moves from the cell 2 132 to the cell 3 133 in Fig. 1 and the intensity of the signal gradually received from the cell 2 132 becomes weak and the intensity of the signal received from the cell 3 133 becomes It becomes strong. When the group moving body 10 reaches the boundary between the cell 2 132 and the cell 3 133, the intensity of the signal received from the cell 2 132 and the cell 3 133 becomes similar, And handover from cell 2 132 to cell 3 133 is performed.

FIG. 2 is a diagram illustrating a group moving body moving between base stations installed in a roadside according to an embodiment of the present invention.

Referring to FIG. 2, the base stations 210, 220, and 230 may perform wireless communication with the group mobile station 100 using millimeter waves through an antenna.

In general, a base station is a term including a radio unit (RU) and a digital unit (RU), but a base station according to an embodiment of the present invention may refer to an antenna and an RU connected thereto, DU may be included in a DU-like station, such as a base station controller.

The group moving body 100 includes at least one processor, a memory, and a wireless communication unit. The group moving body 100 can relay communication between the base station and a plurality of terminals located within the group moving body 100. That is, the group mobile terminal 100 may serve as a terminal in relation to a base station and may serve as a base station in relation to a plurality of terminals located inside the group mobile terminal 100. [ The millimeter wave is located in the frequency band of 30-300GHz, and has a stronger directivity and a larger path loss than the conventional cellular frequency band. On the other hand, since the wavelength of the carrier frequency is short, the antenna can be miniaturized and can be used for manufacturing a small array antenna. Also, a directional beam can be formed, so that the path loss of the signal can be compensated.

2, when group moving body 100 belongs to cell 1 201 and cell 2 202, group moving body 100 moves to cell 1 201 due to the directionality of the transmitting and receiving antenna of group moving body 100, Or cell 2 (202). When the group moving body 100 includes both the transceiver for cell 1 201 and the transceiver for cell 2 202, the transmission / reception for each cell in one of cell 1 201 or cell 2 202 The device can be controlled. However, the transceiver for cell 1 (201) can not prevent interference from cell 2 (202) due to high directionality for cell 1 (201) even when group mobile 100 is located within the coverage of cell 2 Small experience. The transceiver for cell 2 202 also has a small experience of interference from cell 1 201 due to the high directionality of cell 2 202 even though group mobile 100 is located within the coverage of cell 1 201 . That is, when the base station performs radio communication with the group mobile station 100 using millimeter waves as shown in FIG. 2, the coverage of the cells formed by each base station may overlap due to the high directionality of the transceiver. In FIG. 2, the transceiver included in the group moving body 100 is for the cell 2 202, and the group moving body 100 moves toward the cell 4 (204). When the group moving body 100 is different from the boundary between the cell 2 202 and the cell 4 204, the intensity of the signal received by the group moving body 100 is higher than that of the signal of the cell 2 202 and that of the cell 4 204 The group mobile 100 performs handover from cell 2 202 to cell 4 204 because the signals are similar. When the group mobile 100 passes through the second base station 220, the signal strength from the cell 2 202 is drastically reduced and the signal strength from the cell 4 204 is gradually reduced The strength of the received signal from cell 2 202 and cell 4 204 can be similar.

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

Referring to FIG. 3, a wireless communication system according to an embodiment of the present invention includes a base station control apparatus 200, a plurality of base stations 220 and 230, and a group moving body 100.

The base station control apparatus 200 processes a digital signal and transmits / receives the signals to / from a plurality of base stations 220 and 230, and is connected to each base station through an optical fiber or the like. For example, the base station control apparatus 200 may be a device such as a DU-concentrating station including a plurality of data units (DU) for each base station, and may be transmitted / received to / from a plurality of base stations via wired lines, Signal can be controlled. The signal transmission time between the base station controller 200 and each base station may be proportional to the refractive index of the optical fiber and the length of the optical fiber. 3, the signal transmission time between the base station controller 200 and the second base station 220 is Δ 2 and the signal transmission time between the base station controller 200 and the third base station 230 is Δ 3 to be.

The plurality of base stations are located along the movement path of the group moving body 100 and receive signals from the group moving body 100 and transmit the signals to the base station control apparatus 200 or signals to be transmitted to the group moving body 100, (200). When performing the digital signal processing in the base station control apparatus 200 according to an embodiment of the present invention, a plurality of base stations according to an embodiment of the present invention may include an antenna and an RU, respectively.

The group moving body 100 is a transportation means (such as a bus, a train or a high-speed railroad) including a transceiver for performing wireless communication with a plurality of base stations located on a path, and a plurality of users having wireless communication equipment are boarded .

3, the time at which the signal transmitted from the second base station 220 arrives at the group mobile 100 is t 2 , and the signal transmitted from the third base station 230 reaches the group mobile 100 Time is t 3 . Since the arrival time of the signal can be determined in proportion to the distance between the group mobile unit 100 and the base station, if the second base station 220 and the third base station 230 simultaneously transmit signals to the group mobile unit 100, The base station 100 may receive a signal from the third base station 230 after t 3 -t 2 hours after receiving the signal from the second base station 220.

When the signal transmitted from the base station control apparatus 200 reaches the group mobile station 100 via the second base station 220 (first path), the signal transmission time is t 2 +? 2 , The signal transmission time is t 3 + Δ 3 when the signal transmitted from the base station 230 arrives at the group moving body 100 via the third base station 230 (second path). That is, when the signal generated in the base station controller 200 reaches the group moving body 100 through the first path and the second path, the difference (? 23 ) of the signal transmission time is expressed by Equation 1 below.

Figure pat00001

4A and 4B are diagrams illustrating a frame offset of a digital signal according to an exemplary embodiment of the present invention.

4A and 4B, a frame offset of a digital signal according to an exemplary embodiment of the present invention includes a digital signal (D 2 ) 402 arriving at a group moving body 100 through a second base station 220, Can be calculated based on the signal transmission time difference (? 23 ) between the digital signal (D 3 ) 403 arriving at the group mobile 100 through the base station 230 and the base station 230.

Referring to FIG. 4A, when? 23 is positive (? 23 > 0) D 3 403 may be transmitted toward the third base station 230 by Δ 23 ahead of D 2 402. That is, each bar shown in Figs. 4A and 4B represents a digital signal, showing that D 3 (403) in FIG. 4A is transmitted toward the third base station 230 ahead of D 2 (402) by Δ 23 have. Therefore, D 2 402 and D 3 403 can reach group moving body 100 at the same time.

Referring to FIG. 4B, when? 23 is negative (? 23 D 2 402 and D 3 403 are transmitted toward the second base station 220 by Δ 23 before D 3 403 and therefore D 2 402 and D 3 403 are transmitted to group mobile station 100 ). ≪ / RTI >

5, 6, and 7 are diagrams illustrating frame offsets of a straight line section according to an embodiment of the present invention.

5 to 7 show frame offsets of the digital signals 501 to 50B when 11 base stations are connected to one base station control apparatus 200. Eleven base stations are located on the movement path of the group mobile station 100 It is located in a straight line section.

In one embodiment of the present invention, when the refractive index of the optical fiber from the base station controller 200 to each base station is 1.5, the delay time Δ n required for moving the signal transmitted to the optical fiber by 1 km is 4.95 μs ) Is assumed to be 1 / 1.5 times the speed of light, and the delay time t n required for the signal transferred from the base station to the group moving body 100 by 1 km is 3.3 μs (that is, .

Table 1 shows frame offsets for each base station when the base station controller 200 is located near the sixth base station 260. It is assumed in Table 1 that the base station control apparatus 200 is located closest to the sixth base station 260 and the group mobile station 100 moves from the first base station 210 to the eleventh base station 2B0. Therefore, the optical fiber distance to the sixth base station 260 is 0, and the distance between the group mobile station 100 and the first base station 210 is zero.

Base station
number Distance [km]
(Optical fiber) Time [㎲]
(? N ) Distance [km]
(air) Time [㎲]
(t n ) Time [㎲]
(t n + Δ n ) Difference [㎲] ratio
(? = 1.65 s) One 5 24.75 0 0 24.75 8.25 5Δ 2 4 19.8 One 3.3 23.1 6.6 4Δ 3 3 14.85 2 6.6 21.45 4.95 3Δ 4 2 9.9 3 9.9 19.8 3.3 2Δ 5 One 4.95 4 13.2 18.15 1.65 1Δ 6 0 0 5 16.5 16.5 0 0 7 One 4.95 6 19.8 24.75 8.25 5Δ 8 2 9.9 7 23.1 33 16.5 10Δ 9 3 14.85 8 26.4 41.25 24.75 15Δ 10 4 19.8 9 29.7 49.5 33 20Δ 11 5 24.75 10 33 57.75 41.25 25Δ

Table 2 shows frame offsets for each base station when the base station controller 200 is located near the eleventh base station 2B0. It is assumed that the base station control apparatus 200 is located closest to the eleventh base station 2B0 in Table 2 and that the group moving body 100 moves from the first base station 210 to the eleventh base station 2B0. Therefore, the optical fiber distance to the eleventh base station 2B0 is zero, and the distance between the group mobile unit 100 and the first base station 210 is zero.

Base station
number Distance [km]
(Optical fiber) Time [㎲]
(? N ) Distance [km]
(air) Time [㎲]
(t n ) Time [㎲]
(t n + Δ n ) Difference [㎲] ratio
(? = 1.65 s) One 10 49.5 0 0 49.5 16.5 10 2 9 44.55 One 3.3 47.85 14.85 9 3 8 39.6 2 6.6 46.2 13.2 8 4 7 34.65 3 9.9 44.55 11.55 7 5 6 29.7 4 13.2 42.9 9.9 6 6 5 24.75 5 16.5 41.25 8.25 5 7 4 19.8 6 19.8 39.6 6.6 4 8 3 14.85 7 23.1 37.95 4.95 3 9 2 9.9 8 26.4 36.3 3.3 2 10 One 4.95 9 29.7 34.65 1.65 One 11 0 0 10 33 33 0 0

Table 3 shows the frame offsets for each base station when the base station controller 200 is located near the first base station 210. It is assumed in Table 3 that the base station control apparatus 200 is located closest to the first base station 210 and that the group mobile station 100 moves from the first base station 210 to the eleventh base station 2B0. Therefore, the optical fiber distance to the first base station 210 is zero, and the distance between the group mobile 100 and the first base station 210 is zero.

Base station
number Distance [km]
(Optical fiber) Time [㎲]
(? N ) Distance [km]
(air) Time [㎲]
(t n ) Time [㎲]
(t n + Δ n ) Difference [㎲] ratio
(? = 1.65 s) One 0 0 0 0 0 0 0Δ 2 One 4.95 One 3.3 8.25 8.25 5Δ 3 2 9.9 2 6.6 16.5 16.5 10Δ 4 3 14.85 3 9.9 24.75 24.75 15Δ 5 4 19.8 4 13.2 33 33 20Δ 6 5 24.75 5 16.5 41.25 41.25 25Δ 7 6 29.7 6 19.8 49.5 49.5 30Δ 8 7 34.65 7 23.1 57.75 57.75 35Δ 9 8 39.6 8 26.4 66 66 40Δ 10 9 44.55 9 29.7 74.25 74.25 45Δ 11 10 49.5 10 33 82.5 82.5 50Δ

5 to 7, a base station control apparatus 200 according to an exemplary embodiment of the present invention transmits a signal to be transmitted to a group mobile station 100 to a plurality of base stations at different timings based on a frame offset, The signals to be transmitted to the group mobile station 100 can reach the group mobile station 100 at the same timing all through the antennas included in the plurality of base stations.

Alternatively, the base station control apparatus 200 according to another embodiment of the present invention notifies the calculated frame offsets to a plurality of base stations, and the plurality of base stations, in accordance with the time and frame offset synchronized by the base station control apparatus 200, Lt; RTI ID = 0.0 > 100 < / RTI > Thereafter, signals transmitted at different timings from the plurality of base stations can reach the group mobile station 100 at the same timing.

8 is a flowchart illustrating a base station control method of a base station control apparatus according to an embodiment of the present invention.

Referring to FIG. 8, the base station control apparatus 200 calculates a signal delay time between a group mobile station and each base station, and between each base station and the base station control apparatus 200 (S801). The base station control apparatus 200 according to an embodiment of the present invention calculates a first delay time related to a signal delay between the group mobile terminal and each base station based on the distance between the group mobile terminal and each base station, Can be calculated. Based on the distance between each base station and the base station control device 200 and the signal transmission speed in the wire line between each base station and the base station control device 200, The second delay time can be calculated based on the signal delay between the base station 200 and the base station.

Then, the base station controller 200 calculates a frame offset for each base station based on the first delay time and the second delay time of each base station (S802). The base station control apparatus 200 according to an exemplary embodiment of the present invention calculates a final delay time by adding a first delay time and a second delay time of each base station, compares the calculated last delay time with each base station, And determines the reference base station having the smallest time. The base station controller 200 can determine the difference in the final delay time between the reference base station and the other base station as a frame offset for each base station.

Then, the base station control apparatus 200 transmits data to be transmitted to the group mobile station 100 to each base station based on the frame offset for each base station (S803). Therefore, although the data of the group mobile station 100 transmitted from the base station controller 200 is different from the distance between each base station and the group mobile station 100 and the distance between the base station controller 200 and each base station, The group moving body 100 can be reached at the same time.

The base station that has transmitted the signal to the group moving body 100 can stop signal transmission under the control of the base station control device 200. [ The base station control apparatus 200 according to an exemplary embodiment of the present invention can determine the suspension time point of signal transmission based on the uplink signal of the group mobile station 100 in step S804. And may be determined according to a scheme of assigning a cell ID to a base station.

The base station control apparatus 200 according to an embodiment of the present invention may assign the same cell ID to a plurality of base stations connected to the base station control apparatus 200 or may assign different cell IDs to each of the base stations. Even if the group mobile terminal 100 moves from the coverage of the first base station to the coverage of the second base station in the case where the base station controller 200 assigns the same cell ID to a plurality of base stations connected to the base station controller 200, Since the base station and the second base station are connected to the same base station controller 200 and have the same cell ID, the group mobile terminal 100 can not detect that the base station has changed. That is, since the pilot signal transmitted from each base station coincides with the starting point and the signal itself is the same, the group mobile 100 can not recognize that the cell has been changed, and the group mobile 100 moves as if it moves within one cell . When the group mobile 100 moves to the coverage of the third base station, the first base station can stop signal transmission. In one embodiment of the present invention, a time point at which the group mobile station 100 stops signal transmission at each base station after passing through coverage may be determined based on uplink feedback. The group mobile station 100 periodically measures the strength of the pilot signal and transmits the measurement result on the uplink. The base station control apparatus 200 transmits the measurement result of each base station based on the uplink signal received from the group mobile station 100 It is possible to determine the stopping point. Alternatively, the base station control apparatus 200 according to another embodiment of the present invention can determine a signal transmission stop time point of each base station through an uplink sounding reference signal received from the group mobile station 100. That is, the base station control apparatus 200 determines a base station in which the group mobile station 100 is located based on the uplink sounding signal of the group mobile station 100, and determines a base station to stop signal transmission. When the base station controller 200 assigns a different cell ID to each of a plurality of base stations connected to the base station controller 200, the signals depending on the cell ID are distinguished from each other, It is possible to distinguish the cell that has transmitted the currently received signal and to feed back the uplink signal accordingly. At this time, the base station controller 200 may detect an uplink signal of the group mobile station 100 and determine an appropriate base station according to the movement of the group mobile station 100. If a different cell ID is assigned to a plurality of base stations connected to the base station controller 200, a pilot signal or a reference signal (RS) for demodulating the cell ID may act as an interference. .

FIG. 9 is a diagram illustrating a group moving body operating a curve section according to an embodiment of the present invention, and FIGS. 10 and 11 are diagrams illustrating a method of calculating a frame offset in a curve section.

In the orthogonal frequency division multiplexing (OFDM) system, if the start point of a signal is out of a cyclic prefix (CP) period, the signal can act as an interference to the group moving body 100. Therefore, in an OFDM system based on a multi-carrier transmission scheme, synchronization for each base station needs to be synchronized within the CP interval. In the case of LTE, the short CP is 4.7 μs or 5.2 μs. If the carrier frequency is changed to a millimeter wave, the subcarrier spacing, symbol length, and CP of the OFDM system must be changed. It may be about 1/5 or 1/8 of the CP of the communication system. That is, in a mobile communication system using millimeter waves, the synchronization for each base station needs to be maintained within a CP length shorter than the CP of a mobile communication system such as LTE.

Referring to FIG. 9, the group mobile station 100 that has passed the coverage of the third base station 230 moves to the coverage of the fourth to sixth base stations located in the curve section. At this time, a difference may occur in the signal transmission time of the signal received by the group mobile unit 100 according to the curvature radius of the curve segment and the base station position of the curve segment.

10 and 11, the radius of curvature of the curve section is 640 m, and the distance between the fourth base station 240 and the fifth base station 250 in FIG. 10 is 502 m. In FIG. 11, the fourth base station 240 and the fifth The distance between base stations 250 is 1,004 meters.

10, the time at which the signal transmitted from the fifth base station 250 reaches the first point 1000 and the time at which the signal transmitted from the fourth base station 240 reaches the first point 1000 The time when the signal transmitted from the fifth base station 250 reaches the second point (the point at which the fourth base station is located) and the time when the signal transmitted from the fourth base station 240 reaches the second point The difference (DELTA b-DELTA a) between DELTA a and DELTA b is 0.08 mu s. At this time, the first point 1000 may be the start point of the curve section of the moving path of the group moving body 100.

11, the difference between the time when the signal transmitted from the fifth base station 250 reaches the first point 1000 and the time when the signal transmitted from the fourth base station 240 reaches the first point 1000 ? C, and the difference between the time when the signal transmitted from the fifth base station 250 reaches the second point and the time when the signal transmitted from the fourth base station 240 reaches the second point is? D,? C and? D The difference? D -? C is 0.48 占 퐏. That is, even though millimeter waves are used in the wireless communication system according to an embodiment of the present invention, in both cases, the frame offset may be included in the CP section. In the embodiment of the present invention, the base stations of the curved sections are arranged at a shorter interval in the straight line section so that the arrival times of signals according to the positions of the group moving body 100 adjusted based on the frame offset can be safely included within the CP section .

On the other hand, frame offsets may be applied differently depending on the direction of a cell formed in each base station. For example, when the cell direction is opposite to the moving direction of the group moving body 100 (cell group A) and when the cell direction is the same direction (cell group B) as the moving direction of the group moving body 100, Can be applied differently. 3, the directions of the cells 2 and 4 formed in the first base station and the second base station are opposite to the moving direction of the group moving body 100, and the frame offset shown in FIGS. Direction. 5 to 7, the frame offset is a value calculated for the cell group A. According to another embodiment of the present invention, the frame offset can be calculated for the cell group B whose cell direction is the same as the moving direction of the group moving body 100 according to the method described above, It is different from the frame offset.

As described above, according to the embodiment of the present invention, the group moving body 100 can receive the signal at the same time by the predetermined frame offset. At this time, the frame offset may be determined in advance based on the distance between the base station controller 200 and the base station and the distance between the base station and the group mobile station 100. That is, the base station control apparatus 200 transmits a signal to each base station in consideration of a frame offset, and a signal delayed in time according to the frame offset can reach the group moving body 100 at the same time. For example, when the base station control apparatus 200 transmits the same data to the first base station and the second base station, the group mobile station 100 can receive the same data from the first base station and the second base station at the same time point It is not necessary to perform the handover even if the coverage of the first base station moves to the coverage of the second base station. In this case, since the group mobile station 100 receives at least two identical data synchronized with each other according to the embodiment of the present invention, the inter-base station hand It may not perform over. Alternatively, the group mobile station 100 according to another embodiment of the present invention may not perform synchronization for each base station at the boundaries of the first base station and the second base station, thereby greatly simplifying the inter-base station handover procedure.

12 is a diagram illustrating a wireless communication system including a plurality of base station control apparatuses according to an embodiment of the present invention.

Even when the group mobile terminal 100 moves between antennas connected to different base station control apparatuses 200, the group mobile terminal 100 can transmit the frame offset for the different base station control apparatuses 200 The handover procedure can be greatly simplified. The base station control apparatus 200 according to an exemplary embodiment of the present invention sets a reference timing with the neighboring base station control apparatus 300 through a global positioning system (GPS) The frame offset for the neighboring base station controller 300 can be calculated by sharing the number of DUs, the antenna interval, or the location information of the base station controller 200 with the neighboring base station controller 300. The base station control apparatus 200 according to an embodiment of the present invention provides the same data to the group mobile station 100 at the same time based on the frame offset of the neighboring base station control apparatus 300 calculated in the above- And the group mobile terminal 100 can greatly simplify the handover procedure even when the group mobile terminal 100 moves from the coverage of the base station controller 200 to the coverage of the neighboring base station controller 300. [

As described above, according to an embodiment of the present invention, data is transmitted to a group mobile station based on a frame offset calculated based on a delay time of a signal between a group mobile station, a base station, and a base station control device, Synchronization can be omitted at the time of handover, so that handover can be easily performed. In addition, by controlling the frame offset of the neighboring base station control apparatus by the base station control apparatus, the group mobile station can simplify the handover procedure even when entering the coverage of the base station connected to another base station control apparatus, Can be performed.

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

Referring to FIG. 13, a wireless communication system according to an embodiment of the present invention includes a base station 510 and a terminal 1320.

The base station 1310 includes a processor 1311, a memory 1313, and a radio frequency unit (RF unit) 1313. The memory 1313 may be coupled to the processor 1311 to store various information for driving the processor 1311 or at least one program to be executed by the processor 1311. [ The wireless communication unit 1313 is connected to the processor 1311 to transmit and receive a wireless signal. The processor 1311 may implement the functions, processes, or methods suggested by embodiments of the present invention. In this case, the wireless interface protocol layer in the wireless communication system according to an embodiment of the present invention may be implemented by the processor 1311. [ The operation of the base station 1310 according to an embodiment of the present invention may be implemented by the processor 1311. [

The terminal 1320 includes a processor 1321, a memory 1322, and a wireless communication unit 1323. The memory 1322 may be coupled to the processor 1321 to store various information for driving the process 1321. [ The wireless communication unit 1323 may be connected to the processor 1321 to transmit and receive wireless signals. The processor 1321 may implement the functions, steps, or methods suggested by embodiments of the present invention. In this case, in the wireless communication system according to an embodiment of the present invention, the wireless interface protocol layer may be implemented by the processor 1321. The operation of terminal 1320 according to an embodiment of the present invention may be implemented by processor 1321. [

In an embodiment of the present invention, the memory may be located inside or outside the processor, and the memory may be connected to the processor via various means already known. The memory may be any type of volatile or nonvolatile storage medium, e.g., the memory may include read-only memory (ROM) or random access memory (RAM).

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 base station control method of a base station control device for controlling a plurality of base stations disposed along a movement path of a group mobile body,
Determining a frame offset for the plurality of base stations based on a first delay time occurring between the group moving body and the plurality of base stations and a second delay time occurring between the plurality of base stations and the base station control apparatus, And
And transmitting data to be transmitted to the group mobile station to the plurality of base stations based on the frame offset
/ RTI > The method of claim 1,
Wherein the determining comprises:
Calculating the first delay time for each of the plurality of base stations through a first distance between the group mobile unit and the plurality of base stations and a transmission speed of an airborne signal,
A second distance between the plurality of base stations and the base station controller and a second delay time for each of the plurality of base stations through a transmission speed of a signal in an optical fiber connecting the plurality of base stations and the base station controller Calculating, and
Determining the frame offset based on the first delay time and the second delay time
/ RTI > 3. The method of claim 2,
Wherein determining the frame offset based on the first delay time and the second delay time comprises:
Determining a first base station having a smallest final delay time which is a sum of the first delay time and the second delay time among the plurality of base stations, and
Determining the frame offset based on a final delay time of the base station excluding the first base station and a final delay time of the first base station among the plurality of base stations
/ RTI > The method of claim 1,
Wherein the first interval between the plurality of base stations is shorter than the second interval between base stations disposed along a straight path of movement when the movement path is a curve. The method of claim 1,
Assigning the same cell ID to the plurality of base stations, and
Determining a signal transmission stop time point of the plurality of base stations based on an uplink signal of the group mobile station
Further comprising the steps of: The method of claim 5,
Wherein the uplink signal is a sounding signal of the group mobile station. The method of claim 5,
Wherein the uplink signal includes a measurement result of a strength of a signal corresponding to the data measured by the group mobile unit. The method of claim 1,
Assigning different cell IDs to the plurality of base stations, and
Determining a signal transmission stop time point of the plurality of base stations based on an uplink signal generated based on the cell ID in the group mobile station
Further comprising the steps of: A base station control apparatus for controlling a plurality of base stations arranged along a movement path of a group moving body,
At least one processor,
Memory, and
Wireless communication section
Lt; / RTI >
The at least one processor executing at least one program stored in the memory,
Determining a frame offset for the plurality of base stations based on a first delay time occurring between the group mobile unit and the plurality of base stations and a second delay time occurring between the plurality of base stations and the base station control unit , And
And transmitting data to be transmitted to the group mobile station to the plurality of base stations based on the frame offset
The base station controlling apparatus comprising: The method of claim 9,
Wherein the at least one processor, when performing the determining,
Calculating the first delay time for each of the plurality of base stations through a first distance between the group mobile unit and the plurality of base stations and a transmission speed of an airborne signal,
A second distance between the plurality of base stations and the base station controller and a second delay time for each of the plurality of base stations through a transmission speed of a signal in an optical fiber connecting the plurality of base stations and the base station controller Calculating, and
Determining the frame offset based on the first delay time and the second delay time
The base station controlling apparatus comprising: 11. The method of claim 10,
Wherein the at least one processor, when performing the step of determining the frame offset based on the first delay time and the second delay time,
Determining a first base station having a smallest final delay time which is a sum of the first delay time and the second delay time among the plurality of base stations, and
Determining the frame offset based on a final delay time of the base station excluding the first base station and a final delay time of the first base station among the plurality of base stations
The base station controlling apparatus comprising: The method of claim 9,
Wherein the first interval between the plurality of base stations is shorter than the second interval between base stations disposed along a straight path of movement when the movement path is a curve. The method of claim 9,
The at least one processor executing the at least one program,
Assigning the same cell ID to the plurality of base stations, and
Determining a signal transmission stop time point of the plurality of base stations based on an uplink signal of the group mobile station
To the base station. The method of claim 13,
Wherein the uplink signal is a sounding signal of the group moving object. The method of claim 13,
Wherein the uplink signal includes a measurement result of an intensity of a signal corresponding to the data measured by the group mobile unit. The method of claim 9,
The at least one processor executing the at least one program,
Assigning different cell IDs to the plurality of base stations, and
Determining a signal transmission stop time point of the plurality of base stations based on an uplink signal generated based on the cell ID in the group mobile station
To the base station. A data transmission method of a base station arranged along a movement path of a group mobile body,
Receiving a frame offset from a base station controller of the base station with a neighboring base station of the base station;
And transmitting the data to the group mobile based on the frame offset
Gt; The method of claim 17,
Wherein the frame offset is calculated based on a first delay time occurring between the group mobile station and the base station and a second delay time occurring between the base station and the base station control apparatus. The method of claim 17,
Wherein the interval between the base station and the neighboring base station is shorter than the interval between other base stations disposed along a straight path that is a straight line when the movement path is a curve. The method of claim 17,
Receiving an uplink signal from the group mobile station, and
Stopping the transmission in accordance with a signal transmission stop time point for the data determined based on the uplink signal
Further comprising the steps of:
KR1020150110763A 2014-08-07 2015-08-05 Method and apparatus for controlling base station KR20160019057A (en)

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KR1020140101964 2014-08-07
KR20140101964 2014-08-07

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