KR100737075B1 - Radio base station and mobile communication system - Google Patents

Abstract

In order to realize a radio base station and a mobile communication system capable of shortening the transmission time of retransmission data or normal data at the time of handover and thereby ensuring transmission allocation time, a buffer holding communication data to the terminal and a received signal A wireless base station is configured by an extractor for extracting a communication request signal and a scheduler for controlling the transmission of the communication data based on an output signal of the extractor, and the scheduler executes a handover when a handover request is detected. Before doing so, the buffer is controlled to raise the priority of data transmission to the terminal to be handed over and to transmit data preferentially.

Extraction unit, transmission allocation time, handover target, terminal, mobile communication system

Description

Wireless base station and its data transmission method {RADIO BASE STATION AND MOBILE COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless base stations and mobile communication systems, and more particularly, to wireless base stations and mobile communication systems used for Wideband Code Division Multiple Access (W-CDMA) and the like.

In recent years, the development of W-CDMA is expected as one of the high speed packet communication systems in the next generation mobile communication system.

In mobile communication using a packet such as W-CDMA, specifications are examined in the 3rd Generation Partnership Project (3GPP), and a wireless base station (hereafter simply a base station) and a terminal (mobile phone, etc.) are determined using the protocol determined here. Packet communication is performed between the terminals.

At present, in 3GPP, a study of the HSDPA (High Speed Downlink Packet Access) method has been conducted to further perform high-speed packet communication.

1.1 About HSDPA

This HSDPA is a technique for making packet communication in a downward direction (communication from a base station to a terminal) at a high speed of 10 Mbps. As described above, the HSDPA has been studied to standardize to Release 5, which is a specification of 3GPP. Compared to the release 99 specification, the wireless channel configuration, retransmission control, and introduction of the scheduler unit are major changes.

Hereinafter, the configuration of the radio channel will be briefly described, and the scheduler unit directly related to the present invention will be described.

1.2 About HSDPA Wireless Channel

As shown in Fig. 26, HSDPA is realized by setting the following five types of radio lines between the base station BTS and the mobile terminal MS.

(1) DL HS-DSCH (Downlink High Speed-Dedicated Shared CHannel)

(2) DL HS-SCCH (Downlink High Speed-Shared Control CHannel)

(3) UL HS-DPCCH (Uplink High Speed-Dedicated Physical Control CHannel)

(4) Downlink Associate Dedicated Physical CHannel (DL A DPCH)

(5) Downlink Associate Dedicated Physical CHannel (UL A DPCH)

(1) DL HS-DSCH is a channel for transmitting radio packet data from the base station BTS to the terminal MS. The data mounted on the DL HS-DSCH 1 is encoded by a turbo code or the like.

 (2) DL HS-SCCH is a channel for transmitting information such as encoding information, a modulation scheme, the number of transmission bits, and the like of a radio packet transmitted by the DL HS-DSCH 1.

 (3) The UL HS-DPCCH is a channel for transmitting a reception status (whether or not a packet could be received), the number of bits that can be received, and the like from the terminal MS to the base station BTS.

 (4) DL A-DPCH and (5) UL A-DPCH are radio channels separately installed in each terminal MS and base station BTS. This channel is used from the prior release 99.

1.3 Retransmission Control and Scheduler Section

In the conventional release 99, retransmission control is performed by a radio line control station (RNC) above the base station. That is, as shown in Fig. 27, when the terminal MS receives the packet P1 from the base station BTS by the DL HS-DSCH (Fig. 27 ①), it checks the reception quality and the like (Fig. 27 ②) and makes an error. When the retransmission request NACK (Fig. 27) is found, the retransmission request NACK is raised to the radio channel control station, and the packet P1 is retransmitted (Fig. 27) through the base station BTS.

On the other hand, in Release 5, the following two points were made in order to realize high-speed packet transmission, that is, improvement of effective transmission speed (throughput).

(1) The retransmission interval is narrowed by moving the retransmission control to the base station.

(2) Introduction of the scheduler unit which sets and transmits priorities according to the contents of the service to be transmitted or the state to the terminal.

These are briefly described below.

(1) Resend Control

The flow of the retransmission control is the same as that of the above-described FIG. 27, and the configuration of the terminal in this case is shown in FIG. 28 and the configuration of the base station is shown in FIG.

In the terminal MS, as shown in FIG. 28, the packet transmitted by the above-described HS-DSCH is received by the receiver 34, demodulated and decoded by the demodulator 35, and then the retransmission control unit 36 is performed. A checks the reception status of the packet (for example, whether or not it was received without error) by looking at the CRC added to the packet.

When the retransmission control unit 36 determines that there is no error, for example, the retransmission control unit 36 transmits an ACK (acknowledgement) signal via the modulation unit 32 and the transmission unit 33 using the UL HS-DPCCH described above. Requests the base station BTS for transmission.

On the other hand, when it is determined that there is an error, the retransmission control section 36 similarly transmits a NACK (retransmission request) signal using the UL HS-DPPCH to make a retransmission request for the base station BTS. At this time, for example, a retransmission request is made until it can be received without error.

On the other hand, in the base station BTS, as shown in FIG. 29, the receiver 6 receives the UL HS-DPCCH packet and demodulates and decodes it by the demodulator 7. FIG. Thereafter, the ACK / NACK extractor 8 extracts the ACK / NACK signal from the terminal MS and transfers the signal to the scheduler 10.

When the scheduler 10 receives the NACK signal, the scheduler 10 retransmits the data stored in the retransmission buffer 3 via the modulator 4 and the transmitter 5. When the ACK signal is received, the information stored in the retransmission buffer 3 is discarded, the data is extracted from the normal buffer 2 and stored in the retransmission buffer 3, and the modulator 4 and the transmitter 5 The transmission is performed via).

In addition, although the retransmission control part may be provided instead of the scheduler part 10, and the retransmission buffer 3 may be provided in the modulation part 4, as described below, retransmission control is carried out to the scheduler part 10. By way of example, the retransmission buffer 3 uses an example provided at the front end of the modulator 4.

(2) About the scheduler unit

The function of the scheduler unit is described below.

The data for each terminal transmitted from the upper level is held in the normal buffer 2 for each terminal. Subsequently, the terminal reception status information extraction section 9 extracts the reception status (for example, C / I, etc.) of the packet transmitted from the terminal from the demodulation signal of the demodulation section 7, and the scheduler section 10 extracts the received status. To pass on.

Using the reception status information, the scheduler unit 10 determines which transmission to which terminal is to be prioritized, and controls a switch (not shown). Then, the normal data whose transmission order is determined is stored in the retransmission buffer 3 from the normal buffer 2, and modulated by the modulator 4 and transmitted from the transmission unit 5.

Here, as a method of determining which terminal to transmit to, the Max C / I method, the Round Robin method, the Proportional Fairness method and the like are known. In particular, in a selection method using C / I such as the Max C / I method, C / I is preferentially selected from a good terminal. For example, the Max C / I method is a method of determining the order of transmission or allocation time in order from the best reception state, that is, the best C / I when the C / I of each terminal is viewed. to be.

At this time, as shown in FIG. 30, when the terminal MS is located near the boundary of the cell CL, C / I is relatively degraded, so that no opportunity for transmission is allocated or the transmission time is shortened.

1.4 Problems with Scheduling

As described above, for a terminal located near the cell boundary, the reception situation (for example, C / I) is generally bad. This is because the distance from the base station to the terminal is so great that the power of " C ", i.e., the carrier, is attenuated, while " I " It is because C / I falls because it becomes large.

At this time, when the scheduler of the base station preferentially allocates from the terminal having good C / I, as described above, the terminal near the cell boundary has not been given or has been given an opportunity for transmission since the C / I is bad. Even if the allocation time is shortened. As a result, there is a problem that the throughput of the terminal deteriorates or, in the worst case, communication is not possible.

1.5 Problems in Handover

(1) Handover and Retransmission Control

As shown in Fig. 31, the terminal MS collectively refers to the operation of changing the connection destination by moving from the cell CL1 of the base station BTS1 to the cell CL2 of the base station BTS2. The handover is classified into a soft handover, a hard handover, a difference frequency handover, a cell change, and the like by the scheme, hereinafter referred to as handover.

In addition, the HS-DSCH performs cell change from the specification (GPP Release 5) without performing conventional soft handover or hard handover. A cell change is a connection between cells, and once a line is disconnected and reconnected to a cell of a moving destination, similar to hard handover.

On the other hand, the UL A DPCH and the DL A DPCH can also perform soft handover. This is a method of handover by simply changing the spreading code without changing the frequency, and handover is possible without cutting the line.

Here, the handover in the W-CDMA system is controlled by a radio line control station (RNC) as shown in FIG.

The case where the operation of the handover is applied to, for example, a high-speed packet communication (HSDPA) by the base station having the configuration shown in FIG. 29 will be described.

Communication is performed between the terminal MS and the base station BTS1, and it is determined that the handover to the base station BTS2 has been determined by the radio line control station RNC, and retransmission is being performed. Therefore, retransmission is performed in the retransmission buffer 3 shown in FIG. Assume that data is stored.

At this time, in order to perform a handover, the following three processes can be considered.

a) Discard this retransmission data.

b) Transmit to base station BTS2 of the handover destination.

c) Retransmission control is performed until the packet transmission is completed (the terminal can receive it without error).

(2) Problems caused by handover and retransmission control

The above handover method a) cannot be selected because data is missing. Method b) is the most feasible method, but unlike the conventional method, data transmission between base stations is required. This will be described in detail below with reference to FIGS. 29 and 32. In addition, suppose that retransmission is being performed when the handover is determined by the radio channel control station RNC.

First, a handover request is transmitted from the radio line control station RNC to the handover control unit 11 (step S141 in Fig. 29 or 32). Upon receiving this, the handover control unit 11 requests the scheduler unit 10 to transmit data (step S142). The scheduler unit 10 first requests the retransmission buffer 3 to transmit the retransmission data of the handover target terminal to the base station BTS2 as the handover destination (step S143), and the retransmission buffer 3 transmits radio line control. The base station BTS2 is transmitted to the base station BTS2 via the station RNC (step S144). After completion of the transmission, the scheduler is notified of completion (step S145).

Subsequently, the scheduler unit 10 requests the normal buffer 2 for the handover target terminal to similarly transmit the received data to the base station BTS2 (step S146), and the buffer 2 passes through the radio line control station RNC. Then, the transfer is executed (step S147). After completion of the transfer, the scheduler 10 reports the completion of the transfer (step S148).

Upon receiving this, the scheduler unit 10 reports to the handover control unit that all transmissions have been completed (step S149), and the handover control unit 11 reports to the radio line control station RNC that preparation for handover is possible ( Step S150). After this, handover is performed (step S151).

Subsequently, the method c) is simple because conventional control can be used. However, as described above, the terminal to be handed over is usually located near the boundary of the cell, and the C / I is set to be set by the scheduler because the C / I is bad. It is considered that the priority is low and the time is short (in the worst case it is not allocated).

Therefore, in the case of handover after waiting for completion of retransmission at the time of handover, the operation time becomes long, or in the worst case, there is a problem such that the handover cannot be performed forever because there is no time.

This handover problem has similarly occurred not only with the retransmission data stored in the retransmission buffer but also with the normal data stored in the normal buffer.

In addition, as another conventional technique, when there is no free portion of a radio channel for a priority call (a call of high priority or a call of high QoS), a radio which preferentially allocates the radio channel at the free time point is performed. Priority call connection devices for communication systems have been proposed (see Patent Document 1, for example).

Patent Document 1: Japanese Patent Laid-Open No. 11-8876 (Summary 1)

In the prior art, however, the priority call is assigned without handover or truncation for the purpose of keeping the transmission rate or the like, and the priority is assigned to the high priority (that is, the attribute of the service). In any case, the communication is prioritized as long as the service does not change.

Accordingly, an object of the present invention is to realize a radio base station and a mobile communication system capable of shortening the transmission time of retransmission data or normal data during handover and thus ensuring transmission allocation time in the method c). .

<Start of invention>

In order to achieve the above object, a wireless base station according to the present invention includes a buffer for holding communication data to a terminal, an extractor for extracting a communication request signal from a received signal, and the communication data based on an output signal of the extractor. And a scheduler unit for controlling the sending of the data, and when the scheduler unit detects a handover request, prior to executing the handover, the buffer is arranged to prioritize data transmission prior to performing the handover. It is characterized by controlling.

That is, in the present invention, the output signal of the extracting unit, that is, the NACK signal is output when the received signal includes the retransmission request, and the ACK signal is output when the normal data is requested. Controls the transmission of communication data to the terminal held in the buffer.

At this time, when the scheduler unit detects a handover request, the scheduler unit prioritizes data transmission to the terminal to be handed over to which the scheduler unit knows, so that data transmission from the buffer is preferentially performed.

As a result, regardless of the reception situation or service indicated by the C / I of the handover target terminal or the like, the rank of data transmission in the scheduler unit is increased, which is equivalent to the increase in the transmission allocation time relatively, resulting in a handover. Before performing the data transfer, the data transmission to the handover target terminal is completed, thereby reducing the time required for handover.

In this case, the communication data may be either retransmission data or normal data, and thus the buffer may be either a retransmission buffer or a normal buffer.

When the buffer is a retransmission buffer for storing retransmission data, the buffer further includes a normal buffer for storing normal data, and when the scheduler unit detects that the retransmission buffer is empty, among the normal data held in the normal buffer, Normal data directed to the terminal to be handed over can be transmitted preferentially.

That is, after retransmission data is preferentially transmitted at the time of handover, normal data held in the normal buffer is also preferentially transmitted.

The wireless base station further includes an inflow control unit. In this case, when the scheduler unit detects the handover request, the scheduler unit controls the inflow control unit to stop the inflow of data from an upper level to the terminal of the handover target. Can be.

That is, since data flows into the wireless base station even during the handover, if the inflow control unit stops the inflow of the data in advance, it is possible to further preferential data transmission during the handover.

The above handover request is given, for example, from a radio line control station (RNC).

On the other hand, before the handover request is granted from the radio line control station, the base station can similarly detect the handover request by the following various methods.

First, the base station calculates a signal propagation time between the terminal and the base station from the time of data transmission until receiving the output signal of the extractor, and calculates the distance between the terminal and the base station from the propagation time. The apparatus may further include a terminal distance calculator, and the scheduler may detect the handover request by comparing the distance with a threshold.

In this case, the propagation time calculator and the terminal distance calculator may be included in the scheduler.

That is, data is transmitted from the base station to the terminal to calculate the time until the ACK or NACK signal is returned from the terminal, that is, the signal propagation time between the terminal and the base station, and the distance between the terminal and the base station is calculated from this propagation time. In addition, by comparing this calculated distance with a threshold value of the distance for which handover is required, the scheduler unit has detected that the handover request is detected because the terminal is approaching the cell boundary and the handover request is close.

In this way, after detecting the handover request, the data transmission to the handover target terminal can be raised in the same manner as above to complete the data transmission before the handover.

Alternatively, the base station further includes a terminal receiving field strength information extracting unit for extracting received field strength information calculated and transmitted by the terminal from the received signal, wherein the scheduler compares the received field strength with a threshold to perform the handover. You can also detect a request.

Also in this case, the terminal reception field strength information extraction unit may be included in the scheduler unit.

That is, the scheduler unit can issue a handover request detection by extracting the received electric field strength (or received power) detected by the terminal to the wireless base station and comparing the received electric field strength with a threshold value.

Alternatively, the base station may include a terminal location information extracting unit for extracting terminal location information measured and sent by the terminal, a location information memory for storing location information of the local station, and a distance between the terminal and the base station from the terminal location information and the local station location information. The apparatus may further include a terminal distance calculator configured to calculate a value, and the scheduler may detect the handover request by comparing the distance with a threshold value.

Also in this case, the terminal location information extracting section, the location information memory and the terminal distance calculating section may be included in the scheduler section.

That is, in this case, the scheduler unit calculates the distance between the terminal and the base station from the terminal position information obtained from the terminal and the position information of the own station that can be obtained from the own station in advance, and compares this distance with a threshold to perform handover as described above. Detect requests.

The base station further includes a connection base station number information extracting unit for extracting information on the number of access base stations that the terminal detects and transmits or is supplied from a higher level, and the scheduler unit compares the number of access base stations with a threshold value to determine the number of access base stations. A handover request can be detected.

Also in this case, the base station number information extracting unit may be included in the scheduler unit.

That is, the scheduler unit also receives a handover request by extracting information on the number of access base stations detected from the terminal side or supplied from a higher level such as a radio line control station on the radio base station side and comparing the number of access base stations with a threshold. Can be detected.

The base station further includes a terminal position information extracting unit for extracting terminal position information measured and transmitted by the terminal, a memory for storing past terminal position information extracted by the terminal position information extracting unit, and the terminal position information. And a moving direction calculating section for calculating a moving direction of the terminal from current terminal position information extracted by an extracting unit and past terminal position information stored in the memory, wherein the scheduler unit is configured to request the handover from the moving direction. Can be detected.

Also in this case, the terminal position information extracting unit, the memory and the moving direction calculating unit may be included in the scheduler unit.

That is, in this case, the base station extracts the terminal position information measured by the terminal at the base station, and the scheduler unit calculates the movement direction of the terminal by using the present value and the past value of the terminal position information, thereby the movement direction. As the terminal moves to the cell boundary, the handover request is made.

The base station further includes a terminal position information extracting unit for extracting terminal position information measured and transmitted by the terminal, and a terminal movement direction extracting unit for extracting movement direction information of the terminal calculated and transmitted by the terminal. The scheduler unit may detect the handover request from the terminal location information and the movement direction information.

Also in this case, the terminal position information extraction unit and the terminal movement direction extraction unit may be included in the scheduler unit.

That is, in this case, the base station extracts both the terminal position information measured by the terminal and the movement direction information of the terminal also calculated by the terminal, and the scheduler detects the handover request from the extracted terminal position information and the movement direction information. Is to agenda.

The base station further includes a terminal position information extracting unit for extracting terminal position information measured and transmitted by the terminal, a memory for storing past terminal position information extracted by the terminal position information extracting unit, and the terminal position information. And a moving speed calculating unit for calculating a moving speed of the terminal from current terminal position information extracted by an extracting unit and past terminal position information stored in the memory, wherein the scheduler unit is configured to determine the moving speed and a threshold value. By comparison, the handover request can be detected.

Also in this case, the terminal position information extracting unit, the memory and the moving speed calculating unit may be included in the scheduler unit.

That is, in this case, the movement speed of the terminal is calculated by using the terminal position information measured by the terminal in the base station using the past value and the present value, and the handover request is detected by comparing the movement speed with a threshold value. It is agenda.

In addition, in the present invention, the following various mobile communication system including the wireless base station is provided.

That is, the wireless base station comprises a terminal for calculating and transmitting received field strength information from a received signal, and the wireless base station, wherein the wireless base station extracts the received field strength information and compares the received field strength with a threshold. A mobile communication system for detecting a handover request.

A terminal for measuring and transmitting terminal location information, and the wireless base station, wherein the wireless base station extracts the terminal location information, stores location information of the local station, and stores the terminal location information from the terminal location information and the local station location information. -Calculate a distance between base stations and detect the handover request by comparing the distance with a threshold value.

And a wireless base station configured to detect and transmit access base station number information, and wherein the wireless base station detects the handover request by extracting the access base station number information and comparing the access base station number with a threshold value. Mobile communication system, characterized in that.

In this case, when the received electric field strength is low, the terminal can detect the number of access base station numbers by site diversity.

A terminal configured to calculate and transmit terminal position information, and the wireless base station, wherein the wireless base station extracts the terminal position information and stores past terminal position information extracted by the terminal position information extraction unit. And calculating the movement direction of the terminal from the extracted current terminal position information and the past terminal position information, and detecting the handover request from the movement direction.

And a terminal for calculating and transmitting position information and movement direction information of the terminal, and the wireless base station, wherein the wireless base station extracts the terminal position information and the movement direction information, and moves the terminal position information and movement. And detecting the handover request from the direction information.

And a terminal for measuring and transmitting terminal position information, and the wireless base station, wherein the wireless base station extracts the terminal position information, stores the terminal position information of the past, and extracts the extracted current terminal position information. And calculating the moving speed of the terminal from the terminal location information of the past, and comparing the moving speed with a threshold value to detect the handover request.

In the present invention, there is also provided a wireless base station characterized by providing means for preferentially processing retransmission data for a terminal to be handed over.

1 is a block diagram showing the configuration of a first embodiment of a wireless base station according to the present invention;

FIG. 2 is a flowchart illustrating an operation during handover in a wireless base station according to the present invention shown in FIG. 1.

3 is a block diagram showing a configuration of a second embodiment of a wireless base station according to the present invention;

FIG. 4 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG.

5 is a block diagram showing the configuration of a third embodiment of a wireless base station according to the present invention;

FIG. 6 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG.

7 is a block diagram showing the construction of a fourth embodiment of a wireless base station according to the present invention;

8 is a flowchart showing an example of operation during handover in a wireless base station according to the present invention shown in FIG.

9 is a block diagram showing the construction of a fifth embodiment of a wireless base station according to the present invention;

10 is a block diagram showing the configuration of an embodiment of a terminal corresponding to the wireless base station shown in FIG.

FIG. 11 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG. 9; FIG.

12 is a block diagram showing the construction of a sixth embodiment of a radio base station according to the present invention;

FIG. 13 is a block diagram showing an embodiment of a terminal corresponding to the wireless base station shown in FIG.

FIG. 14 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG. 12; FIG.

15 is a diagram illustrating an example in which a terminal receives diversity from a plurality of base stations.

16 is a block diagram showing the construction of a seventh embodiment of a wireless base station according to the present invention;

17 is a block diagram showing the configuration of an embodiment of a terminal corresponding to the wireless base station shown in FIG.

FIG. 18 is a flow chart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG.

19 is a block diagram showing the construction of an eighth embodiment of a radio base station according to the present invention;

20 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG.

21 is a block diagram showing the construction of a ninth embodiment of a radio base station according to the present invention;

FIG. 22 is a block diagram showing a configuration of an embodiment of a terminal corresponding to the wireless base station shown in FIG. 21;

FIG. 23 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG.

24 is a block diagram showing the construction of a tenth embodiment of a radio base station according to the present invention;

FIG. 25 is a flowchart showing an example of operation during handover in the wireless base station according to the present invention shown in FIG. 24; FIG.

FIG. 26 is a diagram illustrating an HSDPA radio line established between a base station and a terminal in W-CDMA. FIG.

27 is a sequence diagram illustrating retransmission procedure of a base station-terminal period known in the related art.

Fig. 28 is a block diagram showing a configuration example of a terminal known in the related art.

29 is a block diagram showing a configuration example of a conventionally known wireless base station.

30 is a diagram showing the positional relationship between a single cell and a base station and a terminal in the cell.

Fig. 31 is an explanatory diagram when handing over cells.

32 is a flowchart showing an operation performed at the handover in the wireless base station shown in FIG. 29;

<Explanation of symbols for the main parts of the drawings>

1: inflow control unit

2: normal buffer

3: retransmission buffer

4, 32: modulator

5, 33: transmitter

6, 34: receiver

7: demodulator

8: ACK / NACK extraction unit

9: terminal reception status information extraction unit

10: Scheduler part

11: handover control unit

12: propagation time calculation unit

13: terminal distance calculation unit

14: terminal receiving field strength information extraction unit

15: base station location information memory

16: terminal location information extraction unit

17: terminal distance calculation unit

19: terminal location information memory

20: terminal movement direction calculation unit

21: terminal movement direction information extraction unit

22: terminal moving speed calculation unit

30: buffer

35: demodulation unit retransmission control unit

36: retransmission control

37: reception field strength calculation unit

38: GPS unit

39: site diversity control

40: number of access base stations

41: location information memory

42: moving direction calculation unit

<Best Mode for Carrying Out the Invention>

First embodiment (priority transmission of only retransmission data of a handover target terminal)

1 shows a first embodiment of a wireless base station according to the present invention. In this embodiment, in the transmission system, the inflow control unit 1, the normal buffer 2, the retransmission buffer 3, the modulation unit 4, and the transmission unit 5 are serially connected in this order. (6) and the demodulator 7 are connected in series in this order.

The demodulator 7 is connected to an ACK / NACK extractor 8 and a terminal reception state information extractor 9, and to these extractors 8 and 9, a scheduler 10 is further connected. . The scheduler unit 10 is normally interconnected with the buffer 2 and the retransmission buffer 3 and is interconnected with the handover control unit 11.

FIG. 2 shows an example of the operation during handover in the base station BTS shown in FIG. 1, and the operation of the base station of FIG. 1 will be described below according to the flowchart of FIG. 2.

First, it is assumed that a handover request is supplied to a base station BTS from a radio line control station (not shown) to a terminal connected to the base station BTS. This handover request is received at the handover control unit 11 (step S1), and the handover control unit 11 also requests handover control to the scheduler unit 10 (step S2). At this time, it is assumed that the terminal targeted for handover is performing retransmission control.

In addition, the scheduler 10 prioritizes each terminal based on the reception status (for example, C / I) of each terminal, service contents, maximum delay time, or the like, for example, the Max C / I method. To schedule transmission rank.

Since the scheduler unit 10 that has received the handover control preferentially performs retransmission of the terminal to be handed over, in this example, the scheduler unit 10 sets the highest priority (step S3) and transfers this to the retransmission buffer 3. .

After that, the scheduler 10 monitors the output signal of the ACK / NACK extraction unit 8, that is, the ACK signal or the NACK signal (step S4), and when the NACK signal is extracted, retransmission data from the retransmission buffer 3 is performed. Control is performed to retransmit (step S5). When the ACK signal is returned from the terminal, it is confirmed that retransmission to the terminal is completed (step S6).

In this way, after the retransmission is completed, the scheduler unit 10 makes a request for transfer of normal data to the normal buffer 2 (step S7). As a result, the normal buffer 2 transmits the normal data to the base station of the handover destination via the radio line control station (step S8).

When the transfer of the normal data is completed, the normal buffer 2 reports the completion of the transfer to the scheduler unit 10 (step S9), and the scheduler unit 10 receiving this is sent to the handover control unit 11. Report that the preparation for handover is completed (step S10). Therefore, the handover control unit 11 reports to the radio line control station that the preparation for handover is completed (step S11), and the handover proceeds to execution (step S12).

In this way, the scheduler unit 10 retransmits the priority or the highest priority until the new transmission request (ACK signal) is returned from the terminal. As a result, the handover target terminal can be resent in a short time as compared with the case where the priority is not increased. In addition, the request for new transmission means that the terminal could transmit without a certain quality abnormality or error. By retransmission control, an ACK signal is returned from a terminal, and retransmission control is complete | finished.

In this way, since the priority is increased, retransmission to the handover target terminal can be performed smoothly, so that the retransmission buffer 3 can be emptied quickly. In addition, although it has conventionally been necessary to transmit data stored in a retransmission buffer for a terminal to a base station serving as a handover destination, the present invention eliminates the need.

In the above-described embodiment, the scheduler unit may perform handover control by itself. Moreover, you may provide the transmission control part which transmits the data in a buffer. In order to simplify the description, the data transfer and handover in the buffer are normally performed in this order. However, the handover may be performed during the data transfer in the buffer.

Second Embodiment (Transmitting Both Retransmitted Data and Normal Data First)

3 shows a second embodiment of a wireless base station according to the present invention. This embodiment has a basic configuration similar to that of the first embodiment shown in FIG. 1, but differs in operation as shown in FIG. 4. Hereinafter, the operation of the base station of FIG. 3 will be described with reference to FIG. 4.

First, steps S21 to S25 shown in Fig. 4 correspond to steps S1 to S5 shown in Fig. 2, respectively, and in the same manner as in the first embodiment, the retransmission process is performed by raising the transmission priority to the handover target terminal. Is shutting down quickly.

In step S26, the priority of transmission is set not only for the retransmission buffer 3 but also for the normal data directed to the handover target terminal stored in the normal buffer 2. Also in this case, it is not necessary to raise the constant priority but the highest priority.

Then, it is determined whether or not the normal buffer 2 of the handover target terminal is empty (step S27). If it is not empty, normal data in the normal buffer 2 is stored in the retransmission buffer 3, and the modulation unit Transmission is carried out via (4) and the transmission unit 5 (step S28).

Since the result of the normal data transmission is returned from the terminal, the ACK / NACK extraction section 8 monitors this via the receiving section 6 and the demodulation section 7 (step S29), and the ACK / If the output signal of the NACK extraction section 8 is the ACK signal, the process returns to step S27. However, if the NACK extraction section 8 indicates that there is an error in the received packet, the scheduler unit 10 is stored in the retransmission buffer 3. The retransmitted data is resent (step S30). Then, steps S29 and S30 are repeated until the ACK signal is carried on this data.

Returning to step S27, when the normal buffer 2 of the handover target terminal is found to be empty, the preparation completion is reported to the handover control unit 11 as in step S10 in FIG. 2 (step S31), and FIG. Similarly to step S11, a handover preparation completion report is reported to the radio channel control station RNC (step S32), and handover is executed (step S33).

In this manner, it is not necessary to transfer data to the base station of the handover destination via the radio line control station of the normal data, and the control thereof is also unnecessary. In addition, since the signal line is no longer necessary, the circuit scale can be reduced. In addition, since the data transmission is lost in the network between the radio line control station and the base station, the load on the network can be reduced.

As described later, a configuration in which the retransmission buffer 3 and the normal buffer 2 are integrated is also possible.

Third Embodiment (Preventing Inflow of Data from Higher Level at Handover)

5 shows a third embodiment of a wireless base station according to the present invention. The basic structure of this third embodiment is the same as that of the embodiment of Figs. 1 and 3, but the operation is different as shown in the flowchart of Fig. 6. The operation of the third embodiment of FIG. 5 will be described below with reference to the flowchart shown in FIG.

First, after receiving a handover request similarly to step S1 of FIG. 2 or step S21 of FIG. 4, in this embodiment, the scheduler unit 10 controls the inflow control unit 1 to perform a handover target terminal from a higher level. The inflow of data toward the vehicle is stopped (step S42).

As a result, the increase in normal data in the normal buffer 2 can be stopped.

Thereafter, steps S43 to S53 are executed, but these steps correspond to steps S2 to S12 shown in Fig. 2, and after stopping the inflow of data to the handover target terminal in step S42, the handover target Retransmission of the terminal is performed first, and the normal data stored in the normal buffer is transmitted to the base station of the handover destination to perform the handover.

As described above, since the data amount in the normal buffer 2 does not increase, the data transfer time and the time until the transfer completion can be shortened, and the normal buffer can be emptied reliably. In addition, since unnecessary data transmission is eliminated between the radio line control station and the radio base station, it is possible to reduce the load on the network.

Fourth Embodiment (Agenda when handover by estimating propagation distance from propagation time)

7 shows a fourth embodiment of a wireless base station according to the present invention. In this embodiment, the transmission time calculating section 12 and the terminal distance calculating section 13 are different for the base station shown in FIG. 1, 3, or 5. In addition, the buffer 30 uses what integrated the normal buffer 2 and the retransmission buffer 3 in each said embodiment.

FIG. 8 shows the operation of the fourth embodiment shown in FIG. 7, and the operation of the base station BTS of FIG. 7 will be described below with reference to FIG. 8.

First, in each of the above embodiments, it is assumed that a handover request is granted from an upper radio line control station. However, in this embodiment, there is also a case where there is no handover request. In other words, it is assumed that the terminal is near the boundary of the cell, and there is a high possibility that a handover request for handover will be generated in the near future.

For this reason, when the reception of a signal is first started (step S61), the propagation time T of the signal is calculated by the propagation time calculation unit 12 (step S62). The calculation of this propagation time is described below.

The base station BTS mounts the packet P2 on the HS-DSCH and stores the transmitted time from the transmission unit 5 and stores it. Upon receipt of this packet P2, the terminal checks whether the packet P2 contains an error, and if there is an error, returns a NACK signal that is a retransmission request, and if there is no error, an ACK signal requesting new transmission. Is mounted on the HS-DPPCH and returned to the base station.

The base station BTS that has received the signal by the HS-DPCCH extracts the ACK / NACK signal from the ACK / NACK extractor 8 through the receiver 6 and the modulator 7 and then extracts the extracted time. The propagation time calculating section 12 is informed.

As a result, the propagation time calculating section 12 calculates the round trip propagation time T by subtracting a predetermined known system time from the response time from the signal transmission to the reception.

Based on this result, the terminal distance calculation unit 13 calculates the distance L between the base station and the terminal (step S63).

Then, the scheduler 10 inputting this distance L compares the threshold Lth with a significant threshold Lth to the distance at which the handover may be expected (step S64). When the distance L exceeds the threshold Lth, the terminal 10 It is determined that it is near the cell boundary.

In this way, the processing in steps S65 to S74 is executed in the same manner as in the case where the handover request is granted from the radio line control station. That is, these steps S65 to S74 correspond to the steps S3 to S12 shown in FIG. 2 or the steps S43 to S53 shown in FIG. 6, and after normal retransmission of the handover target terminal, the normal data from the normal buffer Is transmitted via a network to perform a handover.

Also in this embodiment, similarly to the second embodiment of FIG. 3, not only retransmission data but also normal data can be transmitted preferentially. This also applies to each of the following examples.

In addition, although the comparison of distance L and the threshold value was performed by the scheduler part 10 here, you may perform inside the terminal distance calculation part 13, or the propagation time calculation part 12 and the terminal distance calculation part ( 13) may be included in the scheduler unit 10.

In addition, in 3GPP, since the above-mentioned transmission timing is defined including the delay caused by radio waves, it is possible to easily calculate the propagation time.

As described above, priority can be determined regardless of the reception situation (C / I) of the terminal. In addition, by increasing the priority, the throughput and transmission delay of the terminal can be improved, so that services requiring high-speed transmission can be provided.

In the case where the terminal is located near the cell boundary, handover is likely to be made in the near future. Therefore, prior to the handover request being issued from the higher level, priority is given to the transmission in the scheduler unit as in the above-described embodiment. When the normal data stored in the normal buffer is transmitted, the handover can be performed more quickly than in the case of actually receiving and executing the handover request.

Fifth Embodiment (Agenda when handover by receiving electric field strength)

9 shows a fifth embodiment of a wireless base station according to the present invention. In this embodiment, the terminal receiving field strength information extraction unit 14 is provided for the base station BTS shown in FIG. 1 and the like. In addition, the buffer 30 uses the thing which integrated the normal buffer 2 and the retransmission buffer 3 similarly to 4th Embodiment mentioned above.

FIG. 10 shows an example of the configuration of the terminal MS corresponding to the base station BTS shown in FIG. 9. The conventional example shown in FIG. 28 differs in that the reception electric field strength calculator 38 is provided.

FIG. 11 is a flowchart showing the operation of the base station BTS shown in FIG. 9. Hereinafter, the operation of the embodiment of FIGS. 9 and 10 will be described along with the flowchart of FIG. 11.

First, when reception is started (step S81), the terminal reception field strength information extraction unit 14 shown in FIG. 9 extracts the reception field strength information included in the demodulation signal obtained from the reception unit 6 and the demodulation unit 7. (Step S82). In this case, the received field strength information may be received power information.

The reception field strength information is received by the reception field strength calculation unit 38 through the reception unit 34 and the demodulation unit 35 by the reception field strength calculation unit 38 through the reception unit 34 and the demodulation unit 35 in the terminal MS shown in FIG. 10. It is calculated as the information of the received electric field strength E of the signal.

The reception field strength calculation unit 38 then sends the calculated reception field strength E to the base station BTS shown in FIG. 9 via the modulation unit 32 and the transmission unit 33, thereby transmitting this reception field strength E. As described above, the terminal reception field strength information extraction unit 14 may extract the same.

The received field strength information thus extracted is sent to the scheduler unit 10 and compared with the threshold value Eth (step S83). As a result, when it is recognized that the received electric field strength E is larger than the threshold value Eth (E> Eth), it is determined that the terminal MS is near the cell boundary, and it is determined that the possibility of handover is large (step S84).

As in the embodiment shown in Fig. 8, retransmission of the handover target terminal is set as the highest priority (step S85), and the following steps S66 to S74 are executed (step S86).

In addition, by using the moving average when calculating the received electric field strength in the terminal, the influence of paging can be reduced. In addition, by controlling the time interval for calculating the average value, it is also possible to lessen the influence of paging.

Also in this embodiment, the scheduler unit 10 may include the terminal reception field strength information extraction unit 14.

After the terminal calculates the received electric field strength, the terminal itself may determine the possibility of handover, and if it is determined that there is a possibility, it may be returned to the base station. In this case, the terminal reception field strength information extractor 14 in the base station BTS may be referred to as a handover decision result extractor.

Sixth Embodiment (Agenda for Handover by Estimating Terminal Distance from Terminal Location Information)

In the fifth embodiment shown in Figs. 9 to 11, the actual handover request is detected by using the received electric field strength. In the sixth embodiment of the radio base station according to the present invention shown in Fig. 12, the position of the terminal is shown. The distance between the terminal and the base station is calculated from the information, thereby requesting the actual handover.

For this reason, in the sixth embodiment shown in FIG. 12, instead of the terminal receiving field strength information extracting unit 14 shown in FIG. 9, the base station position information memory 15, the terminal position information extracting unit 16, and the terminal are used. The distance calculator 17 is used.

FIG. 13 shows an example of the configuration of a terminal MS corresponding to the radio base station BTS of the sixth embodiment shown in FIG. 12. In this embodiment, instead of using the reception field strength calculating section 38 shown in FIG. For example, a GPS (Global Positioning System) unit 38 is used.

The operation of the sixth embodiment shown in FIGS. 12 and 13 will be described below with reference to the flowchart of FIG.

First, the terminal position information extraction unit 16 shown in FIG. 12 extracts the terminal position information based on the demodulation signals from the receiver 6 and the demodulator 7 (step S92). In this case, as shown in Fig. 13, the terminal position information extracts the position information of the own station from the GPS unit 38, and transmits it to the base station side via the modulator 32 and the transmitter 33, It is extracted by the terminal location information extraction unit 16.

The base station position information memory 15 stores the position information of the own station in advance, and is extracted by the base station position information stored in the base station position information memory 15 and the terminal position information extracting unit 16. The terminal distance calculating unit 17 which inputs the terminal position information can calculate the distance L between the terminal and the base station from the position information Pt1 of the terminal and the position information Pt0 of the base station.

The scheduler 10 which inputs this distance L compares with the threshold Lth similarly to the 4th Example shown in FIG.7 and FIG.8 (step S94), and when distance L exceeds the threshold Lth (L) > Lth), steps S65 to S74 are executed similarly to the fifth embodiment shown in FIG.

That is, the scheduler unit 10 raises the priority of data retransmission in the retransmission buffer 3 and transmits the data stored in the normal buffer 2.

In this way, handover can be realized at high speed.

In addition, since the base station does not move, the position measurement may be performed or directly input and stored in the position information memory.

Also in this embodiment, the scheduler 10 may include a base station location information memory 15, a terminal location information extracting unit 16, and a terminal distance calculating unit 17.

Seventh embodiment (Agenda when handovers based on the number of access base stations)

In the above embodiment, the handover request is detected by using the base station-terminal period distance or the received electric field strength. However, when the terminal comes near the cell boundary, the number of connected base stations increases. Therefore, it is possible to detect the actual handover request also by the number of such access base stations.

Here, the site diversity used for detecting the number of access base stations will be briefly described.

Site diversity is a method of transmitting the same data from a plurality of base stations to an arbitrary terminal. As shown in FIG. 15, since the propagation paths of the base station BTS1 and the base station BTS2 are different, diversity gain occurs in the terminal MS. do. If the phases of the radio waves from the base stations BTS1 and BTS2 are the same, the received electric field strengths of the DL A-DPCHs are simply doubled, so that the synthesized waves from the two base stations are received. = 2.

A seventh embodiment using such site diversity is shown in Figs. FIG. 16 shows a seventh embodiment of the base station BTS. In order to know the number of the connected base stations, the connected base station number information extracting unit 18 is provided, and correspondingly, the terminal MS shown in FIG. In the configuration, the electric field strength calculator 37, the site diversity controller 39, and the connected base station number calculator 40 are provided.

The operation of this seventh embodiment will be described below with reference to a flowchart shown in FIG.

First, when the terminal MS is located at a place relatively close to the base station BTS1 or BTS2, since the reception field strength E sent from the reception field strength calculating section 37 to the site diversity control section 39 in the terminal MS is large, the site diver The city control section 39 does not perform the site diversity described above, and therefore the number of access base stations does not calculate the number of access base stations, but when the position control unit is located near the cell boundary, the reception field strength E decreases. Control is performed.

When performing site diversity, the site diversity control unit 39 gives the combined base station number calculating unit 40 a DL-DPCH synthesized wave signal at this time, thereby connecting the base station number calculating unit 40. Can detect the number of currently connected base stations N and send them to the base station via the modulator 32 and the transmitter 33.

In the base station BTS, the connection base station number information N sent from the terminal MS in this way is extracted by the connection base station number information extracting unit 18 (step S102).

The scheduler unit 10 having received this access base station number information compares the access base station number N with its threshold value Nth (step S103), and if the detected access base station number N exceeds the threshold value Nth, the terminal unit 10 determines. Determines that the cell is located near the cell boundary, and executes steps S65 to S74 as in FIG. 11 to raise the priority of retransmission data transmission in the scheduler unit 10 and transmit normal data stored in the normal buffer. The handover is realized at high speed.

This connected base station number information N may be made to notify a terminal or a base station from a higher level, such as a radio line control station.

Also in this embodiment, the scheduler unit 10 may include an access base station number information extraction unit 18.

Eighth Embodiment (Agenda when handovers based on the movement direction of the terminal)

In addition to the base station-terminal period distance, the received electric field strength and the number of access base stations in the above-described embodiment, it is also possible to detect that the terminal can exist near the cell boundary by detecting the moving direction of the terminal.

In the eighth embodiment of the wireless base station according to the present invention shown in Figs. 19 and 20, the terminal moving direction calculating section 20 is replaced with the terminal distance calculating section 17 in the sixth embodiment shown in Fig. 12. The point of use is different.

The operation of the base station shown in FIG. 19 will be described below with reference to the flowchart shown in FIG. 20. In addition, the terminal in this case can use the structural example shown in FIG.

First, the terminal position information extracting unit 16 shown in FIG. 19 extracts the terminal position information Pt1 sent from the terminal (step S112). The terminal position information Pt1 is then stored in the terminal position information memory 19 (step S113).

Further, the terminal position information extracting unit 16 extracts the next terminal position information Pt2 (step S114), and at this point, the terminal moving direction calculating unit 20 is extracted by the terminal position information extracting unit 16. The moving direction D of the terminal is calculated by inputting the current terminal position information Pt2 and the past terminal position information Pt1 stored in the memory 19 (step S115).

The scheduler 10 which inputs the terminal movement direction D calculated by the movement direction calculation unit 20 determines whether the movement direction D is the cell boundary direction (step S116). This can be determined from the movement direction D and the terminal position information Pt2 that the terminal is facing the cell boundary. In this case, steps S65 to S74 are executed in the same manner as in FIG.

However, when it is found that the movement direction D is not the cell boundary direction, the current terminal position information Pt2 is stored in the terminal position information memory 19 as the past terminal position information Pt1 (step S117).

Even in this way, it is possible to realize high-speed handover.

Also in this embodiment, the scheduler unit 10 may include a terminal position information extracting unit 16, a memory 19, and a terminal moving direction calculating unit 20.

Ninth Embodiment (Agenda for handover based on the moving direction of the terminal)

In the eighth embodiment described above, the movement direction of the terminal is calculated, but the calculation of the movement direction is performed by the terminal in the ninth embodiment of the radio base station according to the present invention shown in Figs.

For this reason, in the base station BTS, the memory 19 and the terminal movement direction calculation unit 20 in the eighth embodiment shown in FIG. 19 are not used. Instead, the terminal movement direction information extraction unit 21 is used. Correspondingly, the terminal MS differs from the embodiment of the terminal shown in Fig. 13 in that the positional information memory 41 and the movement direction calculation section 42 are additionally used.

The operation of this ninth embodiment will be described below with reference to the flowchart shown in FIG.

First, in the terminal MS, the positional information Pt1 detected by the GPS unit 38 and the detected positional information Pt1 are once stored in the memory 41, and the current positional information and the past are moved by the movement direction calculation unit 42. By comparing the positional information of each other, the moving direction D of the terminal MS is calculated and sent to the base station BTS via the modulator 32 and the transmitter 23 together with the positional information Pt1.

In the base station BTS, the terminal position information extraction unit 16 extracts the terminal position information Pt1 (step S122), and the terminal movement direction information D is extracted from the terminal movement direction information extraction unit 21 (step S123).

As a result, as in step S116 of FIG. 20, the scheduler unit 10 determines whether the moving direction D is the cell boundary direction (step S124), and if the moving direction D is the cell boundary direction, the step is performed similarly to FIG. S65 to S74 are executed.

In this way, when it is determined that the cell boundary is directed from the movement direction D and the terminal position information Pt1, the priority of retransmission data transmission in the scheduler unit 10 is increased, and the normal data stored in the normal buffer is transmitted. As a result, handover can be realized at a higher speed.

Also in this embodiment, the scheduler unit 10 may include a terminal position information extraction unit 16 and a terminal movement direction information extraction unit 21.

Tenth Embodiment (Agenda when handovers based on movement speed of terminal)

In the eighth and ninth embodiments described above, the control is performed by using the movement direction of the terminal. However, the same determination can be made by using the movement speed of the terminal.

A tenth embodiment for performing such control is shown in FIGS. 24 and 25.

That is, in the base station BTS shown in FIG. 24, the point which uses the terminal movement speed calculation part 22 instead of the mobile terminal direction calculation part 20 in 8th Example shown in FIG. The operation of this embodiment will be described below with reference to the flowchart shown in FIG.

In the flowchart of FIG. 25, steps S131 to S134 correspond to steps S111 to S114 in the flowchart of the eighth embodiment shown in FIG. 20, and the terminal movement speed calculator 22 includes two terminal position information. By inputting Pt1 and Pt2 from the terminal position memory 19 and the terminal position information extracting unit 16, respectively, the moving speed V of the terminal can be calculated using the following equation (step S135).

V = (Pt2-Pt1) / (T2-T1)

T1 and T2 are time points added to the terminal position information detected by the terminal, respectively.

As a result, when it is found that the calculated terminal speed V is larger than the threshold value Vth (step S136), steps S65 to S74 are executed as in FIG. That is, when the moving speed V is large, the priority of retransmission data transmission in the scheduler unit 10 is increased, and handover is performed at high speed by transmitting data stored in a normal buffer.

Even in this case, when it is found that the terminal moving speed V is equal to or less than the threshold Vth, the new current terminal position information Pt2 is stored in the terminal position information memory 19 as the past terminal position information Pt1 (step S137).

Also in this embodiment, the scheduler unit 10 may include a terminal position information extracting unit 16, a terminal position information memory 19, and a terminal moving speed calculating unit 22.

As described above, according to the present invention, the handover target terminal raises the priority at the time of handover, thereby eliminating the need to transmit the retransmission data stored in the retransmission buffer during retransmission to the base station of the handover destination. Similarly, the transfer of normal data stored in the normal buffer is also unnecessary. In addition, since no transmission is necessary, there is no need for control accompanying it.

In addition, when handover is performed, transmission of the data in the buffer can be smoothly and surely performed by stopping the inflow of data to the base station to the terminal.

In addition, when it is determined that the terminal is at the cell boundary using the propagation time, the location information, or the number of access base stations, the throughput of the terminal is improved or the maximum delay time can be improved by raising the rank of data transmission to the terminal. It becomes easy to protect or to do it. In addition, in the case of handover, the same effects as described above can be obtained.

Claims (28)

A buffer holding communication data to the terminal, An extraction unit for extracting a communication request signal from the received signal from the terminal; A scheduler for controlling transmission of the communication data based on an output signal of the extractor Including, And when the scheduler unit detects a handover request, before executing the handover, controls the buffer to raise the priority of data transmission to the terminal to be handed over and transmit the data preferentially. The method of claim 1, When the scheduler unit detects that retransmission data of the communication data is sent to the retransmission buffer and the retransmission buffer is empty, the normal data of the communication data is sent to the normal buffer and among the normal data held in the normal buffer, a handover target A base station for transmitting normal data directed to the terminal of the first. The method of claim 1, A propagation time calculating section for calculating a signal propagation time between the terminal and the base station, from data transmission until receiving an output signal of the extracting section; Terminal distance calculation unit for calculating the distance between the terminal and the base station from the calculated signal propagation time Further provided, The scheduler unit compares the distance with a threshold value and detects that the handover request exists when the distance exceeds the threshold value. The method of claim 1, Terminal reception field strength information extraction unit for extracting the received field strength information calculated and transmitted from the received signal by the terminal Further provided, And the scheduler unit compares the received electric field strength with a threshold and detects that the handover request exists when the received electric field strength exceeds the threshold. The method of claim 1, A terminal location information extraction unit for extracting terminal location information measured and sent by the terminal; A location information memory for storing location information of the own station; A terminal distance calculator for calculating a distance between the terminal and the base station from the terminal position information and the local station position information Further provided, The scheduler unit compares the distance with a threshold value and detects that the handover request exists when the distance exceeds the threshold value. The method of claim 1, Access base station number information extracting unit for extracting information of the access base station number detected or transmitted by the terminal or supplied from a higher level Further provided, And the scheduler unit compares the number of access base stations with a threshold value and detects that the handover request exists when the number of access base stations exceeds the threshold value. The method of claim 1, A terminal location information extraction unit for extracting terminal location information measured and sent by the terminal; A memory for storing past terminal position information extracted by the terminal position information extracting unit; A movement direction calculator for calculating a movement direction of the terminal from current terminal position information extracted by the terminal position information extracting unit and past terminal position information stored in the memory; Further provided, The scheduler unit detects that the handover request exists when the movement direction is a cell boundary direction. The method of claim 1, A terminal location information extraction unit for extracting terminal location information measured and sent by the terminal; Terminal movement direction extraction unit for extracting the movement direction information of the terminal calculated and transmitted by the terminal Further provided, And the scheduler unit detects that there is a handover request when it is determined from the terminal location information and the movement direction information that the terminal is facing a cell boundary. The method of claim 1, A terminal location information extraction unit for extracting terminal location information measured and sent by the terminal; A memory for storing past terminal position information extracted by the terminal position information extracting unit; A movement speed calculator for calculating a movement speed of the terminal from current terminal position information extracted by the terminal position information extractor and past terminal position information stored in the memory; Further provided, And the scheduler unit compares the movement speed with a threshold value and detects that the handover request exists when the movement speed exceeds the threshold value. A data transmission method of a wireless base station, Retaining communication data to the terminal; Extracting a communication request signal from the received signal from the terminal; Controlling the transmission of the communication data based on the output signal by the extraction step Including, And when the handover request is detected, prioritizing the handover, prioritizing data transmission to the terminal to be handed over, and preferentially transmitting data. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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