JP3996077B2 - Data transfer system and radio base station management apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transfer system and a radio base station management apparatus for transmitting moving image data and the like via a radio packet network.
[0002]
[Prior art]
In recent years, the cdma2000 1x EV-DO system has been developed as a next-generation high-speed wireless communication system. In the cdma2000 1x EV-DO method, when the reception state of the terminal is good by switching the modulation method of data transmitted from the base station to the terminal based on the information notified of the reception state received from the mobile communication terminal. Can be used at a high communication rate with a low error tolerance but a high error tolerance when the reception condition is poor.
[0003]
In the cdma2000 1x EV-DO system, the predicted downlink data communication speed (directly indicating the extremely accurate data communication speed obtained by taking into account predictions and corrections by statistical data such as error rate of past downlink data transmission) The terminal side is provided with a DRC (Data Rate Control Bit) as a table, and based on this table, the predicted downlink data communication rate is notified from the terminal to the base station.
The base station performs scheduling based on DRC information from all terminals, determines a terminal that transmits data in the downlink, and transmits data at a requested rate. This scheduling is to transmit data to the terminal with the best channel environment according to the radio wave reception status when there are multiple terminals in the same sector. The larger the number of terminals, the higher the throughput of the entire sector. And the base station can perform efficient data transmission. Thereby, data communication is performed at the various communication rates described above.
[0004]
In the cdma2000 1x EV-DO downlink direction (from the base station to the mobile communication terminal), the time is divided in units of 1/600 second, and only one mobile communication terminal is communicated within that time. In addition, time division multiplex access (TDMA) is employed in which communication is performed with a plurality of portable communication terminals by switching the communication partner portable communication terminal according to time. As a result, it is always possible to transmit data with the maximum power to each mobile communication terminal, and data communication between mobile communication terminals can be performed at the fastest communication speed.
[0005]
As described above, in the cdma2000 1x EV-DO system described above, the data communication speed in the direction from the base station to the mobile communication terminal greatly varies depending on the reception state (for example, reception field strength, carrier-to-interference ratio = CIR) in the mobile communication terminal. It can be said that it is a best effort type wireless packet data communication system.
[0006]
However, the best-effort wireless packet network has a bit error rate, a packet loss rate, a packet delay time, and the like that are higher than those of a wired network due to the characteristics of wireless communication, and a wireless packet using an adaptive modulation method. In the network, since the data transmission bandwidth fluctuates rapidly, there is a problem that the streaming of moving images is hindered.
[0007]
Therefore, a distribution method using UDP (User Datagram Protocol) is the mainstream in conventional moving image distribution systems. For example, as a distribution method to deal with network bandwidth fluctuation, prepare several transmission patterns from low to high transmission rate for moving image data, start distribution from the lowest rate, There is a method of determining a distribution rate at the start by measuring a distributable data rate by transmitting and receiving several IP packets between the server and the client before starting the distribution.
[0008]
However, the method of starting delivery from the lowest rate has a drawback that it must start from the lowest rate even when the reception level is good, that is, when the network bandwidth is high. For this reason, the terminal side was able to see only images with poor quality despite the good reception situation.
In addition, the method of measuring the data rate before the start of distribution has the disadvantages that it is necessary to send and receive extra packets and that it takes time to actually send valid data.
[0009]
On the other hand, as a bit rate control during distribution, there is a distribution method that changes to a higher rate than the current rate if congestion is not detected on the receiving side, and changes to a lower rate than the current rate if congestion is detected. is there. Congestion is detected by packet loss on the receiving side. In other words, when a missing sequence number is detected on the receiving side, or the data of the next sequence number does not reach the receiving side even after a certain period of time has elapsed, a retransmission is requested from the server after detecting the missing sequence number. However, congestion is detected when the data of the corresponding sequence number does not arrive within a certain time (see, for example, Patent Document 1).
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-300634
[Problems to be solved by the invention]
However, during delivery, in order to detect missing sequence numbers from the actually received packets and measure the data rate, when moving from a place with a poor reception level to a good place, there is no congestion. It can only detect up to a certain point with a bandwidth higher than the data rate delivered to Therefore, after switching to a higher rate than the current rate, the congestion state is detected, and if there is no congestion, a method of increasing the delivery rate step by step, such as another higher rate, is used, and the bandwidth suddenly increases. When it becomes larger, there is a drawback that it takes time to reach an optimal rate that can be delivered. Therefore, it takes time to view a moving image with good image quality that can be obtained by the user, and if this is the case, the reception level deteriorates before reaching the optimum rate, and as a result, good image quality cannot be obtained. There was a case.
[0012]
In addition, when the reception level moves from a good place to a bad place, the wireless communication modulation method changes, so the bandwidth of the wireless section is reduced and the arrival time of the packet is delayed. There is a disadvantage that it takes time to detect. For this reason, high-rate distribution data accumulates on the network or in the queue of the radio base station, so that the time until the switched-rate data arrives is delayed. On the other hand, since the packet does not arrive even though the network bandwidth is low, the terminal side requests the server to retransmit the packet at the current high rate. Therefore, there is a problem in that unnecessary data increases, and as a result, effective data passes only at a rate considerably lower than the actual bandwidth, and image quality deterioration such as large frame dropping or image stoppage occurs.
The present invention has been made in view of the above points, and a data transfer system using a wireless packet network that can always keep the reception level of a communication terminal in an optimum state and can perform stable moving image distribution, and An object of the present invention is to provide a radio base station management apparatus.
[0013]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention described in claim 1 includes a plurality of portable terminals, a plurality of radio base stations connected to the plurality of portable terminals, and a radio base that manages the plurality of radio base stations. A data transfer system comprising a station management device, wherein the portable terminal detects position information detection means for detecting current position information, and measurement for measuring the quality of a received signal at the position detected by the position information detection means Means, a requested data transfer rate determining means for determining a requested data transfer rate to be requested to the radio base station according to the quality of the received signal, and the position information and the requested data transfer rate to the radio base station management apparatus. A communication means for transmitting and receiving the guidance direction from the radio base station management device; and a display means for displaying the guidance direction received by the communication means. The base station management device receives the number information of mobile terminals connected to each radio base station from each radio base station, and calculates the data transfer rate at each radio base station based on the number information A data transfer rate calculating means for comparing the data transfer rate of the radio base station connected to the mobile terminal calculated by the data transfer rate calculating means and the requested data transfer rate received from the mobile terminal The portable terminal is connected when the data transfer rate of the radio base station to which the portable terminal is connected is less than the required data transfer rate of the portable terminal based on the result of the comparing means and the comparing means Radio base station selection means for selecting another radio base station having a data transfer rate higher than that of the radio base station, and no data selected by the radio base station selection means. With the position information of the base station, and a guidance direction generating means for generating a guidance direction from the position information of the portable terminal.
[0014]
The invention according to claim 2 is a radio base station management apparatus that manages a plurality of radio base stations to which a plurality of portable terminals are connected, and receives position information and a requested data transfer rate from the portable terminals. Means, number information receiving means for receiving the number information of portable terminals connected to each radio base station from each radio base station, and data transfer for calculating a data transfer rate in each radio base station based on the number information A rate calculating means, and a comparing means for comparing the data transfer rate of the radio base station connected to the portable terminal calculated by the data transfer rate calculating means with the requested data transfer rate received from the portable terminal; From the result of the comparison means, when the data transfer rate of the radio base station to which the mobile terminal is connected is less than the requested data transfer rate of the mobile terminal, A radio base station selection means for selecting another radio base station having a data transfer rate higher than that of the radio base station to which the band terminal is connected, position information of the radio base station selected by the radio base station selection means, Guidance direction generation means for generating a guidance direction from the position information of the portable terminal.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a data transfer system according to an embodiment of the present invention. In FIG. 1, 10 is a mobile phone (mobile terminal), 11 is a base station control device (wireless base station management device), 121 to 123 are wireless base stations, and 13 is a GPS satellite.
The cellular phone 10 includes a CPU 1 that controls each part of the terminal, an RF processing unit (measuring unit, communication unit) 2 that transmits and receives radio waves and measures signal quality, and a GPS processing unit (position information detecting unit) that measures a position. 3, its own terminal direction detection unit 4 that detects which direction the wireless base station 10 is currently communicating with, and a data transfer rate calculation unit (requested data transfer rate determination means for obtaining a data transfer rate request value) ) 5 and a display unit (display means) 9.
The RF processing unit 2 always receives radio waves from a plurality of GPS satellites 13 and transmits / receives to / from a plurality of radio base stations 121 to 123. The GPS processing unit 3 measures the position of the mobile phone 10 from the radio wave from the GPS satellite 13 received by the RF processing unit 2, and outputs the position information as latitude and longitude information.
The base station control device 11 is connected to and managed with the radio base stations 121 to 123. Each of the radio base stations 121 to 123 grasps the number of the plurality of mobile phones that are performing data communication via the base station.
[0016]
Next, the operation of the data transfer system configured as described above will be described with reference to FIG. The mobile phone 10 is wirelessly connected to the wireless base station 121. The RF processing unit 2 measures the intensity of the radio wave transmitted from the radio base station 121 at the current position of the mobile phone 10 600 times per second, and sends it to the data transfer rate calculation unit 5 via the CPU 1. The data transfer rate calculation unit 5 calculates a CIR (Carrier to Interference ratio) of the pilot signal from the value of the radio wave intensity, and replaces it with a required data transfer rate corresponding to the CIR.
When the mobile phone 10 starts data communication, the CPU 1 informs the base station controller 11 of the location information of the terminal obtained by the GPS processing unit 3, the data transfer rate request value calculated by the data transfer rate calculation unit 5, The content / data request information is transmitted via the wireless base station 121 (step S101). The data transfer rate request value is transmitted through a dedicated channel.
[0017]
Receiving each information, the base station control apparatus 11 acquires the number information of the mobile phones performing data communication from the plurality of managed radio base stations 121 to 123 (step S103). Next, the base station controller 11 receives the data transfer rate for the mobile phone 10 of the radio base station 121 and the number of mobile phones 10 connected to the radio base station 121 acquired in step S103 and in step S101. In consideration of the current data transfer rate request value of the mobile phone 10 and the past data transfer rate request value, the optimum slot allocation (scheduling) for the mobile phone 10 is performed and determined (step S105).
[0018]
Next, the base station control device 11 is better than the data transfer rate determined in step S105 because the number of mobile phones performing data communication is small among the managed radio base stations 121 to 123. Select possible radio base stations. In the present embodiment, the wireless base station selected here is assumed to be 122. Next, the base station control device 11 transmits the position information (recommended direction) of the radio base station 122 to the mobile phone 10 together with the determined data transfer rate (step S107).
When the data transfer rate of the radio base station 121 determined in step S105 is higher than the data transfer rates of other radio base stations, the base station control device 11 does not change the radio base station and sets the recommended direction to “0”. "".
The CPU 1 of the mobile phone 10 that has received the position information of the radio base station 122 from the base station control device 11 detects the direction of the radio base station 122 using the own terminal direction detection unit 4 and displays the recommended direction on the display unit 9. (Step S109). FIG. 3 shows an example of the display. If there is a recommended direction, (a) is displayed, and if the current state is maintained, (b) is displayed. The user who has the mobile phone 10 sees the recommended direction displayed on the display unit 9 and moves closer to the radio base station in that direction, so that the communication level of the mobile phone 10 is kept good.
[0019]
As described above, according to the present embodiment, the location information of another radio base station that is considered to be better than the data transfer rate of the currently communicating radio base station is transmitted to the mobile phone. Even if the level deteriorates, transmission and reception of the mobile phone can always be kept in an optimal state, and stable moving image distribution can be performed.
[0020]
As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
[0021]
For example, in the above embodiment, the present invention may be applied to a portable personal computer or a PDA (Personal Digital Assistance) having a wireless communication function.
[0022]
【The invention's effect】
As is apparent from the above description, according to the present invention, the radio base station management apparatus selects a radio base station having a high data transfer rate from among a plurality of radio base stations to be managed, and The guidance direction of the radio base station is displayed. Therefore, even in moving image distribution using a network with large bandwidth fluctuation, it is possible to provide moving image distribution that ensures good image quality.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a data transfer system according to an embodiment of the present invention.
FIG. 2 is an operation diagram of data exchange between the mobile phone 10 and the base station controller 11 in the embodiment.
FIG. 3 is a display example of a recommended direction in the mobile phone 10 of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... RF processing part, 3 ... GPS processing part, 4 ... Self-terminal direction detection part, 5 ... Data transfer rate calculating part, 9 ... Display part, 10 ... Mobile telephone, 11 ... Base station control apparatus, 121 122, 123 ... wireless base stations, 13 ... GPS satellites

Claims (2)

A data transfer system comprising a plurality of mobile terminals, a plurality of radio base stations connected to the plurality of mobile terminals, and a radio base station management device that manages the plurality of radio base stations,
The mobile terminal is
Position information detecting means for detecting current position information;
Measuring means for measuring the quality of the received signal at the position detected by the position information detecting means;
Requested data transfer rate determining means for determining a requested data transfer rate requested to the radio base station according to the quality of the received signal;
Communication means for transmitting the location information and the requested data transfer rate to the radio base station management device and receiving a guidance direction from the radio base station management device;
Display means for displaying the guidance direction received by the communication means;
The radio base station management device,
Number information receiving means for receiving the number of mobile terminals connected to each radio base station from each radio base station;
Data transfer rate calculating means for calculating a data transfer rate in each radio base station based on the number information;
Comparing means for comparing the data transfer rate of the radio base station to which the mobile terminal is connected calculated by the data transfer rate calculating means with the requested data transfer rate received from the mobile terminal;
From the result of the comparison means, when the data transfer rate of the radio base station to which the mobile terminal is connected is less than the requested data transfer rate of the mobile terminal, the radio base station to which the mobile terminal is connected A radio base station selection means for selecting another radio base station having a high data transfer rate;
A data transfer system comprising guidance direction generation means for generating a guidance direction from position information of a radio base station selected by the radio base station selection means and position information of the portable terminal. A radio base station management apparatus that manages a plurality of radio base stations to which a plurality of portable terminals are connected,
Receiving means for receiving position information and a requested data transfer rate from the mobile terminal;
Number information receiving means for receiving the number of mobile terminals connected to each radio base station from each radio base station;
Data transfer rate calculating means for calculating a data transfer rate in each radio base station based on the number information;
Comparing means for comparing the data transfer rate of the radio base station to which the portable terminal is connected calculated by the data transfer rate calculating means and the requested data transfer rate received from the portable terminal;
From the result of the comparison means, when the data transfer rate of the radio base station to which the mobile terminal is connected is less than the requested data transfer rate of the mobile terminal, the radio base station to which the mobile terminal is connected A radio base station selection means for selecting another radio base station having a high data transfer rate;
A radio base station management apparatus comprising guidance direction generation means for generating a guidance direction from position information of a radio base station selected by the radio base station selection means and position information of the mobile terminal.

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