JP2002084256A - Base station, mobile station, wireless data communication system, wireless data communication network buildup method and computer-readable recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base station, a mobile station, a wireless data communication system, a wireless data communication network buildup method and a computer-readable recording medium that require no power control for wireless data communication. SOLUTION: The base station 1 outputs a transmission signal after being subjected to modulation of the spread spectrum communication system adopting the direct spread method and a mobile stations 1.2 and 2.3 receive the transmission signal. Furthermore, the mobile stations 1.2 and 2.3 output a transmission signal after being subjected to modulation by the phase modulation system or the amplitude phase modulation system and the base station 1 receives the transmission signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station, a mobile station, a wireless data communication system, and a wireless data communication network used when a mobile station connects to a network such as the Internet by wireless data communication to exchange data. The present invention relates to a method and a computer-readable recording medium.

[0002]

2. Description of the Related Art Conventionally, when a mobile station performs wireless data communication via a base station, a modulation method of a spread spectrum system has been used in a modulation process during communication in order to prevent the influence of multipath fading. . In this modulation method, it is necessary to perform secondary modulation by a spreading code at a frequency higher than the modulation frequency of an actual communication signal. Also, due to the problem of interference due to the difference in distance between each base station and the mobile station, power control is required in the communication signal transmitting means.

In a mobile station, the modulation scheme is PS
In the case of using K (phase shift keying) and QAM (quadrature amplitude modulation), if the transmission speed of data communication is increased, intersymbol interference occurs due to the influence of multipath fading, and signal degradation occurs. In order to prevent this, diversity reception, an adaptive array antenna, an equalizer, and the like have been developed. Further, as one of general communication methods between a base station and a mobile station, an FDMA (Frequency Division Multiple Access) method or the like is used. Further, transmission signals from the base station and the mobile station are composed of a plurality of packets, the packets include connection control information, and a wireless data communication system and a packet multiple access system (AP) for performing connection control based on the connection control information. (Hereinafter referred to as IPMA) is disclosed in Japanese Patent Application No. 11-014979. Also, a plurality of base stations are connected, and a wireless server that controls connection of the base stations and an IP (Internet Protocol) between the plurality of wireless servers.
l) A wireless data system including a home wireless server for managing addresses is disclosed in Japanese Patent Application No. 10-309228.

[0004]

As described above, conventionally, power control is required in a communication signal transmitting means. However, in mobile communication, power measurement is unstable due to a fading environment. Therefore, there is a problem that power control is difficult. Also, the problem can be dealt with by adding a pilot signal for power control,
There is a problem that transmission efficiency is reduced by adding an extra signal. Further, as a problem caused by performing power control,
Communication management by the base station is mainly performed. Therefore, the communication area is fixed, and mobile stations in the area cannot select a base station. That is, when traffic is concentrated on a certain base station, there is a problem that a call loss occurs due to the restriction on entry.

[0005] Further, when a transmission signal of a mobile station is modulated by a spread spectrum communication system modulation method, it is necessary to transmit a modulated signal spread over a wide band in the spread spectrum communication system. This has a problem that power efficiency is low and is not suitable for transmission from a mobile station such as a mobile terminal. In addition, when a phase modulation method or an amplitude phase modulation method is used as a modulation method in a transmission signal of a base station, diversity reception, an adaptive array antenna, and an equalizer are used to prevent the influence of multipath fading when the transmission speed increases. Must be installed in the mobile station. However, in this case, there is a problem that it is not possible to meet market needs such as improvement of portability due to downsizing of the mobile station and reduction of power consumption.

[0006] When performing high-speed transmission, increasing the symbol rate increases the frequency band according to the number of channels required for the system. When a fixed channel is allocated to the base stations, a certain distance or more is required between the base stations due to the problem of interference. As a result, in order to obtain a sufficient service area, the number of necessary channels increases,
The bandwidth required for the system is increased. UHF (Ultra High Frequency) available for mobile communication
There is a problem that it is difficult to use such a wide frequency band in a frequency band below the cy) band. Further, when performing communication by the FDMA method between the base station and the mobile station, the number of channels allocated during communication between the base station and each mobile station is fixed. For this reason, the number of channels is limited, and there is a problem that entry restriction is caused by an increase in traffic volume.

[0007] The present invention has been made in view of the above-described circumstances, and a base station, a mobile station, a wireless data communication system, a wireless data communication network constructing method, and a computer reading method that do not require power control in wireless data communication. It is an object to provide a possible recording medium. In addition, using a power-efficient modulation method in the mobile station of wireless data communication,
An object of the present invention is to provide a base station, a mobile station, a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium that use a modulation scheme with less influence of multipath fading in the base station.

Further, the present invention provides a base station, a mobile station, a radio data communication system, a radio data communication network construction method, and a computer-readable recording medium that can communicate in a small system frequency band in a radio data communication mobile station and base station. The purpose is to do. In addition, the present invention provides a base station, a mobile station, a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium in which a mobile station and a base station for wireless data communication are less likely to be restricted by the number of channels. The purpose is to:

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In a wireless data communication system according to the present invention, the frequency of a transmission signal of a base station and the frequency of a transmission signal of a mobile station are different. A wireless data communication system that is divided and a transmission signal from the base station and the mobile station includes a plurality of packets, the packets include connection control information, and perform connection control based on the connection control information. The station includes a modulation unit that modulates using a spread spectrum communication method by a direct spread method as a modulation method,
The mobile station is characterized by comprising a modulating means for modulating using a phase modulation method or an amplitude phase modulation method as a modulation method, and a channel dividing means for dividing a transmission signal into frequency channels.

[0010] Thus, the base station includes modulation means for modulating using a spread spectrum communication method by a direct spread method as a modulation method, and the mobile station uses a phase modulation method or an amplitude phase modulation method as a modulation method. Modulating means for modulating,
Since there is provided a channel dividing means for dividing the transmission signal into frequency channels, the base station outputs the modulated transmission signal of the spread spectrum communication system by the direct spreading method, and the mobile station receives the signal. Further, the mobile station outputs a transmission signal after modulation by the phase modulation method or the amplitude phase modulation method,
Received at the base station.

In the wireless data communication system according to the present invention, the base station includes a detecting means for detecting a channel being used by the base station and peripheral base stations and a mobile station, and an idle state by detecting a channel being used. Notifying means for creating channel information and notifying the mobile station by including the free channel information in the connection control information, wherein the mobile station selects a channel based on the free channel information notified by the base station. Means is provided.

In the wireless data communication system according to the present invention, a wireless server to which a plurality of base stations are connected and which controls connection of the base stations, and a home wireless server which manages an IP address among the plurality of wireless servers are further provided. In the wireless data system provided, the base station communicates between the base station and the wireless server or between each base station when notifying the connection control information, and performs connection control including vacant channel information different from surrounding base stations. It is characterized by reporting information.

In a wireless data communication system according to the present invention, a frequency of a transmission signal of a base station and a frequency of a transmission signal of a mobile station are frequency-divided. Modulating means using a method or an amplitude phase modulation method, and a channel dividing means for dividing a transmission signal into frequency channels, the base station comprises:
Detecting means for detecting a channel being used by the base station and peripheral base stations and the mobile station, and notifying means for generating free channel information and notifying the mobile station by detecting the used channel; The station further comprises channel selection means for selecting a channel based on the available channel information broadcast from the base station.

Thus, the mobile station is provided with the modulation means using the phase modulation method or the amplitude phase modulation method as the modulation method and the channel division means for dividing the transmission signal into frequency channels. It outputs a transmission signal and communicates with the base station. Also, the base station
Detecting the channel being used by the base station and the detecting means for detecting the channel used by the base station and the surrounding base station and the mobile station, creating free channel information based on the detected channel, and sending the free channel information to the mobile station. Notify. In addition, the mobile station
Since there is provided a channel selection means for selecting a channel based on the available channel information broadcast from the base station, the mobile station can perform channel selection mainly. In addition, since the mobile station performs communication using an empty channel broadcast from the base station, a fixed channel is not allocated to the base station, and a plurality of shared channels are repeated regardless of the radio wave coverage. Can be used.

Further, in the wireless data communication system according to the present invention, a wireless server to which a plurality of base stations are connected and which controls connection of the base stations, and a home wireless server which manages an IP address among the plurality of wireless servers are further provided. A wireless data system comprising: a base station, when reporting an empty channel, performs communication between a base station and a wireless server, or between each base station, and reports an empty channel different from surrounding base stations. And

[0016] With this, the base station communicates between the base station and the radio server or between each base station when reporting the vacant channel, and reports two or more vacant channels different from those of the surrounding base stations. Even if calls are simultaneously generated from two or more mobile stations in an area where radio wave arrival areas from base stations overlap, a call can be made while avoiding crosstalk caused by selecting the same channel.

Further, in the wireless data communication system according to the present invention, the base station notifies the idle channel by
It is characterized in that the assignment of channels to be preferentially connected between base stations having overlapping communication areas is determined in advance, and an available channel different from surrounding base stations is broadcast based on the determined priority channel.

[0018] With this, the base station determines the assignment of the channel to be preferentially connected between the base stations having overlapping communication areas in advance when notifying the vacant channel, and based on the determined priority channel, the surrounding base station. Since the idle channels different from the above are broadcast, even if the broadcast of the empty channels between the base stations is performed at the same time, it is possible to reduce the possibility that the channels that start communication with the mobile stations collide with the same channel.

Further, the mobile station according to the present invention is a mobile station capable of communicating with a base station using a spread spectrum communication system by a direct spread method as a modulation system.
Demodulating means for demodulating a signal modulated using a spread spectrum method transmitted from a base station, and modulating means for modulating a signal transmitted to the base station using a phase modulation method or an amplitude phase modulation method. It is characterized by having.

Further, in the base station according to the present invention, in the base station capable of communicating with the mobile station according to claim 7, the base station comprises a modulating means for modulating using a spread spectrum communication system by a direct spread method; And a plurality of demodulating means for demodulating a signal modulated by a phase modulation method or an amplitude phase modulation method received from a mobile station.

[0021] In a wireless data communication network construction method according to the present invention, there is provided a wireless data communication network construction method based on the arrangement of base stations according to claim 8, wherein an overlapping area of radio wave coverage from each base station is determined. Reducing the number of radio waves to reach a wider area with the minimum number of base stations, and, in the base station sharing the overlapping area, setting the spreading code in the spread spectrum communication system used in each base station differently. Adjusting the traffic capacity in each area by overlapping radio coverage areas of base stations having different spreading codes in accordance with the number of users and the traffic amount in an area having a large traffic amount. I do.

Thus, the wireless data communication network construction method reduces the overlapping area of the radio wave coverage from each base station, and allows the radio wave to reach a wider area with the minimum number of base stations. In a shared base station, a step of setting different spreading codes in a spread spectrum communication system used in each base station; and in an area having a large traffic volume, a base station having a different spreading code according to the number of users and the traffic volume. By overlapping the radio coverage of stations, regional characteristics (number of local users,
A wireless data communication network that reduces waste of traffic capacity as compared with the related art that is suitable for the traffic amount and the like is constructed.

In the recording medium according to the present invention,
The frequency of the transmission signal of the base station and the transmission signal of the mobile station is frequency-divided, the transmission signal from the base station and the mobile station is composed of a plurality of packets, the packets include connection control information, the connection control information A recording medium recording a program for a mobile station in a wireless data communication system that performs connection control based on the mobile station, the mobile station demodulates a signal modulated by a spread spectrum communication system transmitted from a base station, A step of performing modulation using a phase modulation scheme or an amplitude phase modulation scheme as a modulation scheme of a transmission signal to be transmitted to a base station, and performing a channel selection based on available channel information broadcast from the base station. A computer-readable recording medium that records a program.

In the recording medium according to the present invention,
The frequency of the transmission signal of the base station and the transmission signal of the mobile station is frequency-divided, the transmission signal from the base station and the mobile station is composed of a plurality of packets, the packets include connection control information, the connection control information A recording medium recording a program for a base station in a wireless data communication system that performs connection control based on a base station, wherein the base station modulates using a spread spectrum communication method by a direct spread method, and receives from a mobile station. Demodulating a signal modulated by a phase modulation method or an amplitude phase modulation method; detecting a channel being used by the base station and peripheral base stations and the mobile station; and detecting a channel being used. Creating a free channel information and notifying the mobile station of the information. .

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described through embodiments of the present invention. However, the following embodiments do not limit the invention described in the claims, and all the combinations of the features described in the embodiments are necessary for solving the invention. Not necessarily. FIG. 1 is a block diagram showing a configuration of a transmission signal from a base station to a mobile station according to an embodiment of the present invention. In this figure, reference numeral 1 denotes a base station provided with modulation means for modulating a transmission signal by a spread spectrum method using a direct spreading method. Codes 2 and 3 are spread spectrum systems (DS / SS: DirectSequence /
The mobile station 1 and the mobile station 2 each include a demodulation unit that demodulates a received signal modulated by a spread spectrum (Spread Spectrum). The base station 1 performs a spreading process using an identification number (spreading code) unique to the base station. Further, the spread data is transmitted in a plurality of continuous packets, communication with a mobile station specified by connection control information included in the packet is started, and the data is transmitted to the mobile station.

Next, FIG. 2 is a block diagram showing a configuration of a transmission signal from a mobile station to a base station according to an embodiment of the present invention. The transmission signals from the mobile stations 1 and 2 and the mobile stations 2 and 3 are π / 4 shifted QPSK (Quadrature Ph).
modulating means for modulating the data by an “A.Shift Keying” method. The base station 1 includes a demodulation unit that demodulates a received signal modulated by the π / 4 shift QPSK method.
With the above configuration, the transmission signals from the base station 1 to the mobile stations 1 and 2 and the mobile stations 2 and 3 are modulated by the spread spectrum communication method using the direct spread method, the mobile stations 1 and 2 and the mobile stations 2 and 3.
The transmission signal from the base station 1 to the base station 1 is in a π / 4 shift QPSK modulation scheme. The base station 1 notifies the mobile stations 1 and 2 and the mobile stations 2 and 3 of the available channel information. Mobile station 1
2. The mobile stations 2 and 3 select a vacant channel based on the reported vacant channel information and start communication with the base station 1.

In digital wireless data communication,
By increasing the transmission rate, multipath fading, in particular, the effect of selective fading due to multi-wave delay increases, and communication quality deteriorates, but by using the direct spread spectrum communication method according to the present embodiment, The influence of the selective fading can be improved, and high-speed communication can be performed at the reception of the mobile station.

There is a method of performing multiple access by code-multiplexing a transmission signal of the base station 1. However, since mutual interference occurs, high-precision power control for minimizing interference noise is required. . However, since the power change in fading is large in practice, the data quality is improved to the extent that voice communication can be performed, but it is difficult to obtain the quality that allows data communication. However, although not shown,
In the present embodiment, high-speed communication and multiple access are simultaneously realized by performing packet multiple access using IPMA.

In the reception of the base station 1, a signal modulated by the π / 4 shift QPSK system, which is more likely to cause multipath fading than the mobile station, is received. However, an adaptive array antenna, diversity reception, an equalizer, etc. Be prepared to deal with it. Here, the base station does not need to care about the size of the device and the power consumption as much as the mobile station, and thus the above-described means can be provided.

Next, FIG. 3 is a block diagram showing a configuration of an arrival area of communication radio waves between a plurality of base stations. As shown, a plurality of base stations A and 11, base stations B and 12, and base station C
-Since there is a range where radio waves reach from 13, it is necessary to separate transmission signals from each base station at the intersection of each area. At that time, the mobile station must obtain a certain or more process gain in consideration of the spreading ratio as described below. In addition, the mobile station 14 selects a base station that can optimally receive data while moving, and performs communication.

In this embodiment, the intersection of the above areas is a digital overlay. This is because the digital overlay is used as a means for avoiding problems such as traffic and delay in data communication using the Internet protocol and improving service quality, as described later.

As shown in FIG. 3, in the area where the radio waves reach from the three base stations where the mobile station 14 is located, the other two are treated as interfering waves, so that the respective base station signals can be separated with good quality. can do. The number of overlays Nr when other channels are disturbing waves is represented by an information rate R,
Using the transmission band W and the ratio Eb / No of the energy Eb per signal bit and the noise power spectral density No including the interference of other channels, the minimum number is obtained by the following equation (1). Nr = (W / R) / (Eb / No) (1)

If the allowable bit error rate is set for the communication quality, the minimum value of Eb / No is obtained from the error rate characteristics of the modulation method. Therefore, the information speed and the transmission band are required by setting the communication quality that can separate the respective base stations. In the case of the direct spreading modulation method, the ratio of the transmission band when the information rate is the symbol rate, that is, the spreading ratio (sp
read factor) becomes the same value as the process gain.

In the equation (1), W = 1.25 MH
Assuming that z and Eb / No = 7 dB, R = 1.25 / 14 = 89.3 kps to separate the three base stations.

As described above, by setting the process gain based on the number of installed base stations and the number of overlays, signal degradation due to mutual interference can be suppressed, so that the same frequency can be repeated to perform packet multiplexing using IPMA. And high-speed data transfer.

The area in which the mobile station 14 can voluntarily select an empty channel is the area where the areas intersect in FIG. At this time, the largest number of options are where three areas where the mobile station 14 is located intersect. It is easily conceivable that the greater the number of options, the higher the probability that an appropriate empty channel can be selected. in this way,
The present embodiment is a scheme that can effectively use the intersection area of each base station.

FIG. 4 is a diagram showing digital overlay and multi-user reception. The transmission signal directly spread by the base station identification number repeatedly uses the same frequency band.
Each base station BS (A) (B) distributed at the position shown in FIG.
In the transmission signal from (C), the overlapping area (digital overlay) is an area where multi-user reception is possible. In the mobile station MS1, the RF signal received by the antenna is A / D converted, and then received and collected by the receivers 1, 2, and 3 corresponding to each base station to obtain received data.

In the case of FIG. 4, the mobile station MS1, the base station,
Assuming that the communication speed to MS2 and MS3 is 38.4 kbps, MS1: 38.4 kbps × 3 = 115.2 kbps MS2: 38.4 kbps × 2 = 76.8 kbps MS3: 38.4 kbps can be obtained.

In order to cope with the high-speed data transmission mode, it is necessary to increase the digital overlay portion. Since it is possible to multiplex the number of overlays up to the interference limit, performing multi-user reception using the maximum number of overlays maximizes the frequency use efficiency. DS /
By using the SS method, multi-user reception can be performed by signal processing, that is, software processing. This means that the system can be expanded by installing a new base station and improving the software of the mobile station, and has the function and cost advantage that hardware can be added without requiring new functions. .

FIG. 5 is a diagram showing a state of interference cancellation of a mobile station according to one embodiment. By using the DS / SS communication method, interference can be removed using an adaptive filter or the like. The mobile station communicates with the best receiving base station. However, as a countermeasure in a case where the traffic of the base station is dense and the data transfer is hindered, a method of removing interference can be considered. In this case, unlike the conventional coded multiple access method, the number of interferences is small, so that a definite value can be used instead of an estimation such as interference cancellation in the code multiplexing method, so that easy and accurate cancellation can be performed. It becomes possible. As a result, in the digital overlay portion, it is possible to select a zone independent of the power intensity, and the throughput is improved.

In the case of FIG. 5, the signal from the base station (A) is strong in the mobile station MS1, but the traffic is large and the throughput is reduced. Therefore, the signal of the base station (A) is removed. , The base station (B) or (C) is used to improve the throughput. That is, the mobile station monitors the throughput while communicating with one base station. When the throughput decreases, the mobile station changes its registered base station, communicates with the changed base station, and communicates with the one base station. The interference is removed by deleting the registration of the base station and stopping the communication.

Next, FIG. 6 is a diagram showing the mobile station transmission and the base station broadcast information, and the channel selection of the mobile station will be described based on this diagram. Reference numerals 61a, 61b, 61
c, ... are base stations, and reference numerals 62a, 62b, 62
c and 62d represent mobile stations. In this embodiment, a transmission signal from each mobile station to each base station communicates using four channels divided by frequency division. Thus, the base station is provided with four demodulation circuits for four frequency-divided channels as demodulation circuits for demodulating the transmission signal from the mobile station modulated by the π / 4 shift QPSK method.

As shown in FIG. 6, the base station 61a and the mobile station 62a occupy one channel (channel).
When the mobile station 1b and the mobile station 62b are communicating using 3ch, the base station 61c includes a detecting unit that detects a channel used by the base station 61a and the base station 61b. In addition, the base station 61c, based on the information detected by the detecting means,
It notifies 2c that the available channels are 2ch and 4ch. The mobile station 62c selects either 2ch or 4ch from the notified free channel information and starts communication with the base station 61c. It should be noted that a device capable of measuring the used frequency band, such as a spectrum analyzer, may be used as the detection means. As described above, in communication between a plurality of base stations and a plurality of mobile stations sharing a digital overlay, crosstalk due to overlapping channels can be avoided.

Also, when the mobile station 62c is communicating with the base station 61c using 2ch and there is a communication request from the mobile station 62d to the base station 61c and wants to communicate using 4ch, the base station 61c uses 2ch. And a demodulation circuit for 4ch, so that it can communicate with the mobile station 62c and the mobile station 62d at the same time, and the mobile station 62d can start communication using the 4ch with the base station 61c without any problem. As described above, since the communication from the mobile station is a burst signal based on packet data, in addition to being able to repeatedly use the system band by notifying the above-described connection control information, the base station is provided with a plurality of demodulation circuits, and the Since the number of mobile stations that can be connected simultaneously increases according to the number, it is possible to make it more difficult to restrict entry due to traffic increase as compared with the related art.

Next, FIG. 7 is a diagram showing notification of channel information from a base station in one embodiment. A wireless server 71 includes a plurality of base stations BS (A) .7
2, connected to BS (B) · 72 and BS (C) · 72. In the present embodiment, the number of channels frequency-divided by the mobile station is 6ch. Here, as illustrated, 1ch and 2ch are assigned to the base station BS (A) · 72, 3ch and 4ch are assigned to the base station BS (C) · 72,
(C) 5ch and 6ch are preferentially allocated to 72 as priority channels. As described above, it is possible to prevent the collision of the channel used when communicating with the mobile station between the adjacent base stations.

FIG. 8 shows a network configuration based on the arrangement of base stations in this embodiment. For code multiple access that maximizes capacity by one base station,
In the S / SS system, it is possible to change the intervals between base stations by arranging the base stations according to the used capacity, the number of overlays, and the area.

As a result, in areas such as urban areas where the number of users and demand for high-speed data are considered to be large, the area of the digital overlay is increased, and the number is further increased. In a place where the number of users is not so large, such as a residential area as shown by, the area and the number of digital overlays are appropriately set. Furthermore, when it is conceivable to use only vehicles that are almost moving, as in the case of roads between cities, organic stations such as arranging base stations so that they are not interrupted and configuring a zone with as few base stations as possible. Area design becomes possible.

As a result, it is possible to provide a service with a minimum initial investment, to easily expand the system,
Advantages such as easy design of a wireless data communication network by arrangement of base stations, easy management of base station equipment, and reduction in system maintenance costs are obtained.

Next, one embodiment of a method for constructing a wireless data communication network is shown in FIG. As shown in FIG. 9, generally, the distribution density of mobile terminals is biased. In addition, the bias is often stationary, as described above, where the distribution density is high in urban areas and low in mountainous areas. According to the configuration method of the wireless data communication network according to the present embodiment, first, base stations are arranged such that the digital overlay is reduced, such as area 1A, area 2A, and area 3A in the figure. By doing so, a wider area can be covered by the sum of the three areas. Next, base stations are arranged so that an area where mobile terminal density is high is covered by area 4A. By doing so, the traffic capacity of the area can be increased. With the above method, a wireless data communication network corresponding to the distribution density of mobile terminals can be constructed. Further, since a situation in which a high-performance base station is arranged in an area where the distribution density of mobile terminals is low unlike the conventional case does not occur, the cost can be reduced.
Also, it is simpler to deal with a change in distribution density than in the past.

Further, in this embodiment, it is not necessary to use a high-performance base station having a high traffic capacity as compared with the related art.
In an area where the distribution density of the mobile terminals is high, the area of the base station having the medium traffic capacity may be overlapped.
In areas where the distribution density of mobile terminals is low, low-cost base stations with low traffic capacity are used. Such a construction method can be executed, and thus the degree of freedom in constructing the system is high.

Also, a program for realizing the function of a processing unit that performs various processes in the broadcast information creation processing in each base station and the broadcast information processing in each mobile terminal in FIG. 1 is stored in a computer-readable recording medium. Each process may be performed by recording and causing a computer system to read and execute the program recorded on the recording medium. The “computer system” here means
It includes hardware such as an OS and peripheral devices.

The "computer system" is
If a WW system is used, a homepage providing environment (or display environment) is also included. The “computer-readable recording medium” refers to a floppy (registered trademark) disk, a magneto-optical disk, an RO
M, a portable medium such as a CD-ROM, and a storage device such as a hard disk built in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) inside a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. , For a certain period of time.

The above program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. Further, the above program may be a program for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient. As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments and includes a design and the like within a range not departing from the gist of the present invention.

[0054]

As described above, in the wireless data communication system according to the present invention, the base station includes modulation means for modulating using a spread spectrum communication method by a direct spread method as a modulation method, and the mobile station comprises: Since the modulation system includes a modulation unit that modulates using a phase modulation system or an amplitude phase modulation system and a channel division unit that divides a transmission signal into frequency channels, a base station directly modulates a spread spectrum communication system by a spread spectrum method. The subsequent transmission signal is output and received by the mobile station. Further, the mobile station outputs a transmission signal modulated by the phase modulation method or the amplitude phase modulation method, and the received signal is received by the base station.

In the wireless data communication system according to the present invention, the mobile station includes a modulating means using a phase modulation method or an amplitude phase modulation method as a modulation method, and a channel dividing means for dividing a transmission signal into frequency channels. Therefore, a transmission signal is output using a carrier having a frequency obtained by dividing the channel, and communication is performed with the base station. Further, the base station detects the channel being used by the detecting means for detecting the channel used by the base station and the peripheral base station and the mobile station, creates free channel information based on the detected channel, and The station is notified of the vacant channel information. Further, the mobile station includes channel selection means for selecting a channel based on the available channel information broadcast from the base station, so that the mobile station can perform channel selection mainly by the mobile station. In addition, since the mobile station performs communication using an empty channel notified from the base station,
A fixed channel is not assigned to the base station, and a plurality of shared channels can be used repeatedly regardless of the radio wave coverage.

Further, in the wireless data communication system according to the present invention, the base station notifies the idle channel by
Communication is performed between the base station and the wireless server or between each base station, and a different available channel is notified from the surrounding base stations. Even if a call is generated simultaneously from the mobile stations, it is possible to avoid the crosstalk caused by selecting the same channel and perform the call.

Further, in the wireless data communication system according to the present invention, the base station notifies the idle channel by
Allocation of channels to be preferentially connected between base stations having overlapping communication areas is determined in advance, and based on the determined priority channel, a free channel different from surrounding base stations is broadcast, so that the base station Even if the notification of the vacant channels is performed at the same time, it is possible to reduce the possibility that the channels each starting communication with the mobile station collide with the same channel.

According to a sixth aspect of the present invention, there is provided a method of constructing a wireless data communication network by arranging base stations according to the present invention, wherein an area where radio wave coverage from each base station overlaps is determined. Reducing the number of radio waves to reach a wider area with the minimum number of base stations, setting the carrier frequency of each base station differently in base stations sharing overlapping areas, By overlapping the radio coverage of base stations with different carrier frequencies according to the number of users and the amount of traffic, traffic compared to the past that matches the characteristics of the area (number of users in the area, traffic volume, etc.) Build a wireless data communication network with reduced wasted capacity.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a transmission signal from a base station to a mobile station according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a transmission signal from a mobile station to a base station according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an arrival area of communication radio waves between a plurality of base stations according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating digital overlay and multi-user reception according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a state of interference cancellation of a mobile station according to an embodiment of the present invention.

FIG. 6 is a diagram showing mobile station transmission and base station broadcast information according to an embodiment of the present invention.

FIG. 7 is a diagram showing mobile station transmission and base station broadcast information according to an embodiment of the present invention.

FIG. 8 is a block diagram illustrating a network configuration including a plurality of base stations according to an embodiment of the present invention.

FIG. 9 is a block diagram illustrating a network configuration including a plurality of base stations according to an embodiment of the present invention.

[Explanation of symbols]

 1 base station 2 mobile station 1 3 mobile station 2

Continued on the front page (72) Inventor Takao Yokoshima 1-8-10 Kichijoji Honcho, Musashino City, Tokyo Mitsubishi Materials Corporation Mobile Business Development Center (72) Inventor Kazuyoshi Tari 1-8 Kichijoji Honcho, Musashino City, Tokyo No. 10 Mitsubishi Materials Corporation Mobile Business Development Center (72) Inventor Kenzo Nakamura 1-8-10 Kichijoji Honmachi, Musashino City, Tokyo Mitsubishi Materials Corporation Mobile Business Development Center (72) Inventor Hiroyuki Unoki Tokyo 1-8-10 Kichijoji Honmachi, Musashino City, Tokyo Mitsubishi Materials Corporation Mobile Business Development Center (72) Inventor Takeshi Hattori 3-12-21-205 Seta, Setagaya-ku, Tokyo F-term (reference) 5K022 EE01 EE14 EE24 EE36 5K033 AA01 BA01 BA02 DA19 DB17 5K067 AA02 AA12 AA41 CC08 CC10 CC24 DD19 DD57 EE02 EE10 EE16 EE24 EE54 EE61 JJ02 JJ17 JJ73

Claims (11)

[Claims] 1. The frequency of a transmission signal of a base station and a frequency of a transmission signal of a mobile station are frequency-divided, the transmission signals from the base station and the mobile station include a plurality of packets, the packets including connection control information, In a wireless data communication system that performs connection control based on the connection control information, the base station includes a modulation unit that modulates using a spread spectrum communication method by a direct spread method as a modulation method, wherein the mobile station performs modulation. A wireless data communication system comprising: a modulation unit that modulates a signal using a phase modulation method or an amplitude phase modulation method; and a channel division unit that divides a transmission signal into frequency channels. 2. The base station, the base station and surrounding base stations and a detecting means for detecting a channel being used by the mobile station; and a free channel information created by detecting the used channel. Notifying unit for notifying the mobile station by including free channel information in the connection control information, wherein the mobile station includes a channel selecting unit for selecting a channel based on the free channel information notified by the base station. The wireless data communication system according to claim 1, wherein: 3. A wireless data system comprising: a wireless server to which a plurality of base stations are connected and which controls connection of the base stations; and a home wireless server which manages an IP address among the plurality of wireless servers. Communicates between the base station and the wireless server, or between each base station when notifying the connection control information, and notifies the connection control information including free channel information different from surrounding base stations. The wireless data communication system according to claim 2, wherein 4. In a wireless data communication system in which a frequency of a transmission signal of a base station and a frequency of a transmission signal of a mobile station are frequency-divided, the mobile station includes a modulation unit using a phase modulation method or an amplitude phase modulation method as a modulation method. Channel dividing means for dividing a transmission signal into frequency channels, wherein the base station detects a channel used by the base station and peripheral base stations and the mobile station, and the used channel The mobile station further comprises channel selection means for selecting a channel based on the available channel information broadcast from the base station. A wireless data communication system, comprising: 5. A wireless data system comprising: a wireless server to which a plurality of base stations are connected and which controls connection of the base stations; and a home wireless server for managing an IP address among the plurality of wireless servers. The wireless data communication device according to claim 4, wherein, when notifying the empty channel, communication is performed between a base station and a wireless server or between each base station, and an empty channel different from a surrounding base station is notified. Communications system. 6. The base station, upon notification of the vacant channel, determines in advance the assignment of a channel to be preferentially connected between each base station having an overlapping communication area, and based on the determined priority channel, The wireless data communication system according to claim 5, wherein an empty channel different from that of the station is broadcast. 7. A mobile station capable of communicating with a base station using a spread spectrum communication method by a direct spread method as a modulation method, wherein the mobile station transmits a signal modulated by the spread spectrum method transmitted from the base station. A mobile station comprising: a demodulation unit that demodulates a transmission signal; and a modulation unit that modulates a transmission signal to be transmitted to the base station using a phase modulation method or an amplitude phase modulation method. 8. A base station capable of communicating with a mobile station according to claim 7, wherein the base station modulates the signal using a spread spectrum communication system based on a direct spread method, and a phase received from the mobile station. A base station comprising: a plurality of demodulating means for demodulating a signal modulated by a modulation method or an amplitude phase modulation method. 9. A method for constructing a wireless data communication network by arranging base stations according to claim 8, wherein an overlapping area of radio wave coverage from each base station is reduced, and a minimum number of base stations is used to cover a wider area. Arriving radio waves, setting the spreading code in the spread spectrum communication system used in each base station differently in the base station sharing the overlapping area, and, in an area where the traffic volume is large, the number of users, Adjusting the traffic capacity in each area by overlapping radio wave coverages of base stations having different spreading codes according to the traffic volume. 10. A frequency of a transmission signal of a base station and a frequency of a transmission signal of a mobile station are frequency-divided, transmission signals from the base station and the mobile station are composed of a plurality of packets, the packets including connection control information, A recording medium recording a program for a mobile station in a wireless data communication system that performs connection control based on the connection control information, wherein the mobile station is modulated by a spread spectrum communication system transmitted from the base station. Demodulating a signal, modulating a transmission signal to be transmitted to the base station using a phase modulation method or an amplitude phase modulation method, and selecting a channel based on available channel information broadcast from the base station. And a computer-readable recording medium recording a program for executing the steps of: 11. The frequency of a transmission signal of a base station and a transmission signal of a mobile station are frequency-divided, the transmission signals from the base station and the mobile station include a plurality of packets, the packets including connection control information, A recording medium recording a program for a base station in a wireless data communication system that performs connection control based on the connection control information, wherein the base station modulates using a spread spectrum communication method by a direct spread method. Receiving from the mobile station, demodulating a signal modulated by a phase modulation method or an amplitude phase modulation method, and detecting a channel used by the base station and peripheral base stations and the mobile station, Creating a free channel information based on the detection of the channel being used and notifying the mobile station of the information. Computer readable recording medium.