JP2001157249A - Wireless access system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain adaptability to a communication service where an outgoing channel requires a larger transmission capacity than that of an incoming channel while the C/I of the incoming and outgoing channels is kept nearly the same. SOLUTION: The incoming channel consists of wireless channels each having a small capacity consisting of many frequencies and the outgoing channel consists of wireless channels each having a large capacity consisting of a few frequencies. For example, when a consecutive frequency band of 180 MHz is given for an assigned frequency band, four frequencies (fd1, fd2, fd3, fd4) each having a bandwidth of 28 MHz are assigned to the outgoing channel, 16 frequencies (fu1, fu2, fu3, fu4, fu5, fu6,..., fu14, fu15, fu16) each having a bandwidth of 10 MHz are assigned to the incoming channel, and a 4-sector 4-frequency frequency assignment arrangement is given to the outgoing channel and a 4-sector 16-frequency frequency assignment arrangement is given to the incoming channel according to the assignment above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio access system for wirelessly accessing a communication network of a telecommunications carrier from a subscriber terminal, and more particularly, to selection of a frequency used to reduce interference during radio access. The present invention relates to an improvement in the structure of a wireless device of a subscriber terminal for facilitating frequency change in the arrangement and the selective arrangement.

[0002]

2. Description of the Related Art A network connecting an exchange of a telecommunications carrier to a subscriber terminal used in a general home is called an access network.
As the most common construction, a method of drawing wires from a network to a large number of subscriber terminals is known.

[0003] However, in this system, although the cost for drawing a wire to each of a large number of subscriber terminals is involved, the amount of communication with the subscriber terminals is small, and competition for communication fees intensifies. Medium, difficult to establish as a business.

[0004] Against this background, today, as a method that is advantageous in reducing the communication fee without laying wires, the above-mentioned access network is being newly provided by radio using, for example, quasi-millimeter waves. Evolving.

[0005] In this type of radio access system, the entire service area is divided into cells, a base station and a plurality of subscriber radio stations are arranged for each cell, and a point / point is set between the base station and each subscriber radio station. Two-point multipoint (P-MP)
The basic configuration is to perform communication.

[0006] In expanding the system, a plurality of base stations are arranged at a fixed distance from each other while maintaining the above-mentioned basic configuration, thereby expanding the area of the system. At this time, care is taken so that adjacent base stations do not use different frequencies to cause interference.

[0007] However, the frequencies that can be used by operators are limited, and how to arrange the frequencies used by each base station (P-MP) system is constructed so that the interference can be minimized. It is an important point in the above.

[0008] Interference in this type of conventional system will be described with reference to FIG. In FIG.
0A, 200B, and 200C are base stations arranged in cells A, B, and C, respectively, separated by a predetermined distance. In the cells A, B and C, respectively, the subscriber radio station 1
00A, 100B and 100C are arranged.

Although FIG. 11 discloses only one subscriber radio station for each of the cells A, B, and C, actually, the cells A, B, and C are not used due to the nature of the P-MP system. A plurality of subscriber radio stations are arranged for each C.

In each of the cells A, B and C, for example, a base station 200 installed on the roof of a building such as a building and a subscriber radio apparatus 100 installed in a general home are connected to an uplink (subscriber radio). The communication is performed between the station 100 and the base station 200 and the downlink (from the base station 200 to the subscriber wireless station 100).

Both the uplink and the downlink are configured by a TDMA (time division multiple access) type line in which a plurality of radio channels having different frequency bands are repeatedly used in a time division manner.

In this system, a broad directional characteristic is given to the antenna of the base station 200 in order to cope with communication with a plurality of opposite stations (each of the subscriber radio stations 100 in the cell) via the uplink. Regarding the antenna of the wireless station 100, sharp directional characteristics are given in order to cope with communication with one counter station (base station 200) through the downlink.

Since the antenna of the base station 200 has broad directional characteristics, the interference of the uplink to the base station 200 can be reduced by interference waves from a large number of subscriber radio stations within the range of the directional characteristics. The incoming call must be considered.

For example, in FIG. 11, base station 200A
In addition to the incoming call from the subscriber's wireless station 100A in its own service area (cell A), the subscriber's radio using the same frequency in a distant area (cells B and C) outside its own service area. Interference waves from the stations 100B and 100C also arrive.

On the other hand, with respect to downlink interference,
Since the antenna of the subscriber station 100 has a sharp directional characteristic, it is only necessary to consider interference from one interfering station on the extension from the subscriber station 100 toward the base station 200.

For example, referring to FIG.
For the downlink to 00B, the interference wave from base station 200A arrives, but the interference wave from base station 200C does not arrive.

As described above, in this system, interference is more severe on the uplink than on the downlink.

In such an environment, in the conventional system, the same repetition frequency is used for both the uplink and the downlink for each cell. FIG. 12 is a diagram showing a frequency allocation image of the uplink [FIG. 12A] and the downlink [FIG. 10B] in the case of repetition of 4 sectors and 4 frequencies in the same cell.

This frequency arrangement is realized by, for example, a method in which a repetition frequency is determined so as to satisfy a required C / I (desired wave / interference wave ratio) of an uplink having severe interference, and the same repetition frequency is set in a downlink. Is done.

In this case, since the interference of the downlink is smaller than that of the uplink, the C / I of the uplink and the downlink is reduced.
Becomes imbalanced. In order to solve this problem, the transmission capacity of the downlink must be as small as the transmission capacity of the uplink. For example, in the case of Internet services, the transmission capacity of the downlink is larger than that of the uplink. It becomes difficult to apply to the system.

Incidentally, the radio base station 200 in the conventional system operates with the radio frequency fixed at a radio frequency determined in advance in consideration of the frequency allocation. Therefore, when newly installing the radio base station 200 as described above, the radio device is disassembled after the frequency allocation of the base station 200 is determined, and a filter component capable of selecting the allocated radio frequency is provided. There was no alternative but to deal with the replacement.

In the configuration of the conventional system, the base station 2
Subscriber radio station 100 generated by adding 00
In the rearrangement, it is costly to create a filter component to be mounted on the wireless device of the subscriber wireless station 100, and moreover, much time and labor are required to replace the filter component with an existing filter component. Was.

[0023]

As described above, in the above conventional system, the repetition frequency is determined so as to satisfy the required C / I on the uplink with severe interference, and the same repetition frequency is used on the downlink. The C / I of the line and the downlink become unbalanced, and in order to avoid this, the transmission capacity of the downlink needs to be as small as the uplink, and the downlink has a larger transmission capacity than the uplink. There is a problem that it is difficult to apply to a required system.

Further, in the above-mentioned conventional system, when a request to change the operating frequency of the radio equipment of the subscriber radio station occurs, a filter component capable of selecting a radio frequency intended for an existing filter component inside the radio equipment is provided. Since the replacement was dealt with, the cost of creating a filter component capable of selecting the target radio frequency was increased, and moreover, it took a lot of time and effort to replace this filter component. There has been a problem that the subscriber wireless station cannot be easily relocated due to the addition or the like.

The present invention eliminates the above problems and can be adapted to various communication services in which the downlink requires a larger transmission capacity than the uplink while maintaining the C / I of the uplink and the downlink approximately equal. An object is to provide a wireless access system.

Further, according to the present invention, it is possible to easily change the operating frequency of the radio equipment of the subscriber radio station without requiring complicated work such as replacement of filter parts, and it is possible to easily change the subscriber radio frequency due to the addition of a base station. It is an object of the present invention to provide a radio access system capable of easily relocating stations.

[0027]

In order to achieve the above object, the invention of claim 1 divides an entire service area into cells, and performs point-to-multipoint communication with a base station and a radio line with the base station. In a wireless access system in which a plurality of subscriber wireless stations are arranged for each cell,
The uplink radio line from the subscriber radio station to the base station is configured with a radio channel with small capacity and multi-frequency repetition, and the downlink radio line from the base station to the subscriber radio station is Configured with radio channels with larger capacity and smaller frequency repetition than uplink radio lines,
The repetition frequency of the uplink radio channel and the downlink radio channel is asymmetric.

According to a second aspect of the present invention, the entire service providing area is divided into cells, and a base station and a plurality of subscriber radio stations for performing point-to-multipoint communication with the base station via a radio line are arranged for each cell. In the radio access system, the uplink radio line from the subscriber radio station to the base station is configured by a radio channel with small capacity and multi-frequency repetition, and from the base station to the subscriber radio station. Characterized in that the downstream radio line is constituted by a radio channel using different polarization.

A third aspect of the present invention is characterized in that, in the second aspect of the present invention, the cell is divided into a plurality of sectors, and a plurality of radio channels are allocated to each sector when the uplink is arranged. I do.

The invention of claim 4 provides the above-mentioned claim 1 or 2
In the invention, the subscriber radio station includes a plurality of band-pass filters having different band-pass characteristics, and a switch for switching connection between the band-pass filter and the antenna in the antenna duplexer, and the change-over switch And a filter selection control unit for selectively connecting any of the plurality of band-pass filters to the antenna.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the subscriber's radio station generates a local signal used by the transmitting unit and the receiving unit for performing frequency conversion between the intermediate frequency and the radio frequency. It is characterized by comprising a synthesizer and frequency variable setting control means for variably setting the oscillation frequency of the frequency synthesizer.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the subscriber radio station includes a communication processing means for performing communication processing with an external device, and a frequency setting signal transmitted from the external device. A signal transfer unit that receives the data through a communication processing unit and transfers the received signal to the filter selection control unit and the frequency variable setting control unit, wherein the filter selection control unit and the frequency variable setting control unit transmit the frequency setting signal to the The control of the filter selection and the oscillating frequency variable setting is performed based on this.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the subscriber radio station includes a holding unit for holding the frequency setting signal received from the external device.

[0034]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing an overall configuration of a radio access system according to the present invention. In FIG. 1, each of a cell A and a cell B is one service area of the entire service area of the present system.

In cell A, one base station 200A and a plurality of subscriber radio stations 100-1, 100-2, 100-
3,100-4 are arranged.

The base station 200A and each subscriber radio station 100-
1, 100-2, 100-3, and 100-4, respectively, the uplink (from the subscriber station 100 to the base station 200)
Direction) and downlink (from base station 200 to subscriber radio station 10)
0 direction), and the base station 200A and each of the subscriber's wireless stations 100-1, 100-2, 1
P-MP communication between 00-3 and 100-4 is performed.

Similarly, in cell B, one base station 20
OB and a plurality of subscriber wireless stations 100-11, 100-1
2, 100-13 and 100-14 are arranged, and the base station 2
00A and each subscriber wireless station 100-1, 100-2, 10
P-MP communication using the uplink and the downlink is performed between 0-3 and 100-4, respectively.

The dotted lines in the cells A and B indicate the boundaries of the sectors set in the cells A and B, respectively. In this system, cell A and cell B respectively
It is divided into four sectors, sector 1 to sector 4, and the use frequency of the uplink and the downlink is arranged for each sector.

Further, in the present system, the base station 200A,
200B is connected to a communication network via a communication line 300 and an exchange 400.

Although only the cells A and B are shown in FIG. 1, in practice, in addition to the cells A and B, the same mode (one base station 200 and a plurality of (Where the wireless station 100 is installed), and all the cells cover the entire serviceable area described above.

As described above, the radio access system according to the present invention divides the entire area for providing the subscriber communication service into a plurality of cells, one base station 200 and a plurality of subscriber radio stations for each cell. The base station 100 basically has a configuration in which P-MP communication is performed between the base station 200 and each of the subscriber wireless stations 100 facing the base station 200 for each cell.

In the above-described P-MP communication in each cell, in the system according to the first embodiment, the uplink is constituted by a radio channel of small capacity and multi-frequency repetition, and the downlink is changed to the uplink. It is composed of a radio channel with a large capacity and a low frequency repetition.

FIG. 2 shows an example of an uplink and downlink frequency allocation plan in the system according to the first embodiment. In this example, as the allocated band, in particular, the uplink and the downlink each have 180
It is assumed that a continuous band of MHz is given.

Under these conditions, the downlink is
As shown in (a), four frequencies (fd1, fd2, fd3, fd3: working channels) each having a bandwidth of 28 MHz and one more frequency (protection channel) having the same bandwidth are allocated, A guard band of 20 MHz is secured at each end.

Also, as shown in FIG. 2B, 16 frequencies (fu1, fu) having a bandwidth of 10 MHz are provided on the uplink.
fu2, fu3, fu4, fu5, fu6, ..., fu14, fu15, f
u16: working channel) and one more frequency (standby channel) having the same bandwidth are allocated, and both ends are 5 MHz.
A guard band for each z is secured.

In order to allocate frequencies to the uplink and downlink in accordance with this frequency allocation plan, the configuration of the cells of the entire system and the configuration of the sectors in the cells should be grasped, and the frequencies should be allocated so as to minimize interference. You need to decide.

FIG. 3 is a conceptual diagram showing an example of a downlink frequency allocation in the system according to the first embodiment, and FIG. 4 is a conceptual diagram showing an example of an uplink frequency allocation in the system. .

As a matter common to FIGS. 3 and 4, areas surrounded by solid lines correspond to cells such as cell A and cell B in FIG. 1, respectively.
It corresponds to each base station 200 of the corresponding cell.

A dotted line corresponds to a boundary between four sector areas in each cell. Further, the numbers in each sector separated by the boundary correspond to the frequencies determined by the allocation plan described in FIG.

As can be seen from FIG. 3, in the present embodiment, the downlink is realized by a channel configuration of 4-sector, 4-frequency repetition as in the conventional case (see FIG. 12). FIG.
In each of the four sectors in one cell, each frequency (the number 1,
2, 3, 4) are arranged.

As a specific example, the numeral 1 is, for example,
This corresponds to the frequency fd1 in FIG. Similarly, numerals 2, 3, and 4 correspond to frequencies fd2, fd3, and fd4 in FIG. 2A, respectively.

On the other hand, as shown in FIG. 4, the uplink is realized by a channel configuration in which four sectors and 16 frequencies are repeated. In FIG. 4, each of the frequencies (numbers 1 to 16) according to the above-described frequency allocation plan is allocated to four sectors in one cell.

As a specific example, the numeral 1 is, for example,
This corresponds to the frequency fu1 in FIG. Similarly, the numbers 2,3,4,5,6,7,8,9,10,11,1
2, 13, 14, 15, and 16 respectively correspond to FIG.
At frequencies fu2, fu3, fu4, fu5, fu6, fu7,
fu8, fu9, fu10, fu11, fu12, fu13, fu14, fu
15, fu16.

As described above, in the first embodiment, the downlink (see FIG. 3) is assigned a frequency allocation of four sectors and four frequencies, while the uplink (see FIG. 4) is assigned a frequency allocation of four sectors and sixteen frequencies. The frequency allocation of the uplink and the downlink is imbalanced.

Here, paying attention to the frequency allocation, a comparison will be made between the system according to the present embodiment and the C / I value of the conventional system.

In the conventional system, not only the downlink but also the uplink has a frequency arrangement of 4 sectors and 4 frequencies repetition as shown in FIG.

Now, when FIG. 3 is viewed as an uplink frequency arrangement of the conventional system for convenience, for example, the base station 200 in the second cell from the right and the second cell from the bottom, As the interference from the sector direction to which the frequency 3 is assigned, for example, the interference from the frequency 3 in the fourth cell from the right and the fourth cell from the bottom is received.

Here, assuming that the distance from the base station 200 of each cell to the edge of the cell area is R, the distance from the base station in the second cell from the right to the interfering station in the second cell from the bottom is R. Is 5R.

On the other hand, in this embodiment, the frequency arrangement of 4-sector and 4-frequency repetition shown in FIG. 4 is applied to the downlink, while the frequency arrangement of 4-sector and 4-frequency repetition shown in FIG. 3 is applied to the downlink. Is done.

Accordingly, in the present embodiment, for example, the base station 200 in the second cell from the right and the second cell from the bottom
In the cell, as the interference from the sector direction to which the number 1 frequency is assigned, the cell receives the interference from the number 1 frequency in the sixth cell from the right and the second cell from the top.

In this case, the distance from the base station 200 to the interfering station in the second cell from the right and the second cell from the bottom is 9R, which is longer than that of the conventional system. Accordingly, the system of the present embodiment is smaller in uplink interference than the conventional system, and the C / I value of the system of the present embodiment is better than that of the conventional system.

According to the measurement results of the inventor of the present invention, in the conventional system in which 4-sector, 4-frequency repetition is applied to both the uplink and the downlink, it reflects that the uplink interference is more severe than the downlink. And an unbalanced C / I value of 4.7 dB for the uplink and 10.9 dB for the downlink.

On the other hand, in the case of the system according to the present embodiment in which the uplink is repeated at 16 frequencies and the downlink is repeated at 4 frequencies, the uplink is 12.0 dB, the downlink is 10.9 dB, and both are almost equal. Equal C / I values were obtained.

At this time, as shown in FIG. 2, the up-link and down-link bands have an asymmetrical band allocation in which the down-link band (transmission capacity) is larger than the up-link. Therefore, in the present embodiment, for example, it is useful for efficiently performing a communication service such as an Internet service that requires a larger transmission capacity on the downstream line than the upstream line.

Incidentally, in this type of system, the above-mentioned allocated band of 180 MHz is not always provided as a continuous band as shown in FIG. 2, but may be provided as a discrete band.

In this case, for example, FIG.
As shown in (a), four channels of the band level cannot be secured, and the channel arrangement of four frequency repetition at the band level cannot be performed.

In such an environment, the channel arrangement of four-frequency repetition can be dealt with by reducing the bandwidth per channel. In this case, however, the transmission capacity becomes too small, and for the reasons described above, the Internet service is used. And so on.

From such a viewpoint, in the second embodiment, when usable bands are discretely provided, the uplink is constituted by a radio channel of small capacity and multi-frequency repetition, while the downlink is constituted by It is composed of wireless channels using different polarizations.

FIG. 5 shows an example of an uplink and downlink frequency allocation plan in the system according to the second embodiment. Note that, in this example, the allocated bandwidth, in particular, for the uplink and downlink,
It is assumed that blocks corresponding to 3 Hz (block 1, block 2, and block 3: 180 MHz in total) are discretely allocated to each of the three blocks.

Under these conditions, as for the downlink, as shown in FIG. 5 (a), a frequency of 28 MHz band is allocated from each of the above blocks 1, 2 and 3, and three frequencies (f1, f2) are conveniently used. , F3) are converted to horizontal polarization (f1H, f2H, f3H) and vertical polarization (f1V, f2V, f3V), respectively.
The channel configuration used as

In this case, two frequencies (f
(1, f2) can secure four frequencies (f1H, f1V, f2H, f2V), so that a frequency arrangement of four repetitions of a 28 MHz bandwidth can be realized.

The remaining one frequency (f 3) is 2
It is used as two spare channels (f3H, f3V). Further, a guard band of 1/2 BW is secured at both ends for each of the blocks 1, 2, and 3. Here, BW is a channel interval in the same polarization, and this guard band securing condition is also applied to the uplink.

On the other hand, as shown in FIG. 5 (b), each of the above blocks 1, 2 and 3 has 1
Five frequencies in the 0 MHz band, and 15 frequencies for convenience, are allocated. Of these, 12 frequencies (f1, f2, f
3,..., F11, f12) are used as working channels, and the remaining three frequencies (spare 1, spare 2, and spare 3) are used as spare channels. Further, a guard band of, for example, 5 MHz is secured before and after each of the blocks 1, 2, and 3.

If the bandwidth per channel is 30 MHz in the uplink, a guard band of 15 MHz is required at both ends according to the above guard band securing condition, and even if three blocks are used, three channels (one block per block) are required. Only one channel) can be secured, and four channels required for the 4-sector system cannot be secured.

Therefore, in the second embodiment, the frequency is set to 10 MHz per channel as described above [FIG.
(See (b)). In this case, the guard band needs to be 5 MHz, and 5 blocks per block and 1 block for 3 blocks.
Five channels can be secured.

Allocate three channels from one of the 15 channels to one sector. [In FIG. 5B, of the frequencies indicated by the numerals (1) to (5), the numerals are the same. Are allocated to the same sector], a band of 30 MHz can be secured for each sector, and as a result, a frequency equivalent to five frequencies having a bandwidth of 30 MHz can be secured.

FIG. 6 is a conceptual diagram showing an example of downlink frequency allocation in the system according to the second embodiment, and FIG. 7 is a conceptual diagram showing an example of uplink frequency allocation in the system. is there.

FIGS. 6 and 7 are similar to FIGS. 3 and 4. That is, in FIGS. 6 and 7, the regions surrounded by solid lines are the cells A and B in FIG. 1, respectively.
, Etc., and the black circles in the area correspond to the respective base stations 200 of the cell.

The dotted line corresponds to the boundary between four sector areas in each cell. Further, the numbers in each sector separated by the boundary correspond to the frequencies determined by the allocation plan described in FIG.

As can be seen from FIG. 6, in the present embodiment, the downlink is realized by a channel configuration in which four sectors and four channels are repeated. In FIG. 6, 4 cells in one cell
In each of the sectors, each channel (1H, 1V, 2H, 2H) according to the frequency allocation plan shown in FIG.
V).

Here, 1H is a channel that uses the frequency of the 28 MHz band allocated from the block 1 in FIG.
Is a channel that uses the same frequency by vertical polarization. Also, 2H is a channel that uses the frequency of the 28 MHz band allocated from the block 2 in FIG. 5A by horizontal polarization, and 2V is a channel that uses the same frequency by vertical polarization.

On the other hand, as shown in FIG. 7, the uplink is realized by a channel configuration of 4-sector, 4-frequency repetition. In FIG. 7, four sectors in one cell include:
Each of the frequencies (numbers 1 to 4) along the frequency allocation plan shown in FIG.

However, in this embodiment, each of the above numerals 1
Each of the frequencies indicated by .about.4 is a combination of three frequency bands.

As a specific example, the frequencies corresponding to the numeral 1 are, for example, the frequencies fu1 and fu in FIG.
2. It has a frequency band combining fu3. Similarly, the numerals 2, 3, and 4 respectively correspond to FIG.
The frequencies (fu4, fu5, fu6) and (fu7,
fu8, fu9) and (fu10, fu11, fu12).

As described above, in the second embodiment, when the usable band is given as a plurality of discrete blocks,
The uplink (see FIG. 7) has a radio channel configuration using a small capacity and multi-frequency repetition and combining and using a plurality of frequencies for each sector, while the downlink (see FIG. 6).
) Is a wireless channel configuration using different polarization.

In the second embodiment, a plurality of channels are allocated to each sector while the bandwidth per channel of the uplink is reduced, so that the transmission capacity of the uplink is always set to a certain value or more. Can be maintained.

Further, since different polarizations are used for the downlink, a usable band per discrete block can be widened (sufficient transmission capacity corresponding to the band can be secured), and Internet services can be provided. For example, it is possible to maintain the applicability to a system in which a downstream line requires a larger transmission capacity than an upstream line.

In the present embodiment, even when the uplink is a small-capacity multi-frequency repetition and different polarizations are used for the downlink, required C / I can be secured for both the uplink and the downlink. .

According to the inventor of the present invention, the cross polarization discrimination in the downlink using different polarization is set to 15 dB, and the
As a result of measuring the C / I value on the assumption that the interference is within 0 km, 23.2d is obtained for the four frequency repetition of the uplink.
B, 2 for repetition of two frequencies (different polarization) in the downlink
A measurement result of 2.2 dB was obtained.

That is, according to the present embodiment, even when different polarizations are used, the required C / I (the required C / I
Is set to, for example, 22.1 dB).

When the available bandwidth is discretely given, it is conceivable to use different polarizations not only for the downlink but also for the uplink, but in this case, the following dangers may occur. Accompany.

This will be described with reference to FIG. Assume now that FIG. 6 is viewed as a channel arrangement diagram of repetition of two frequencies and four different polarizations for the uplink.

Here, paying attention to the 2V sector indicated by oblique lines in the figure, if the distance from the base station 200 (black circle) of the cell to the end of the cell area is R, the shortest interfering station is the base station. It will be at a distance of 3.5R from 200.

However, if the antenna of the subscriber radio station 100 using 2H at a distance (upper side in the figure) is tilted due to, for example, contact with a person, the subscriber radio station 100 will have the above 2V.
Interfering station to the base station 200 that governs the sector of
The shortest interfering station distance from the base station 200 is 2.1
Changes to R.

Considering the interference from one interfering station, the C / I value when the above distance R is set to 1 km and the suppression of the interference by the antenna is considered is 2 when the distance is 3.5R.
In the case of a distance of 3.5 dB and 2.1R, it becomes 13.9 dB.

Here, the required C / I value of this system is 2
If it is set to 2.1 dB, the required C / I value cannot be achieved due to the inclination of the antenna or the like due to an accident such as the above-mentioned human contact.

As described above, in the uplink, the subscriber's radio station 100 is likely to encounter the above-mentioned accidents and the like, and there is a high risk of lowering the C / I value. And

On the other hand, in the case of the downlink, the antenna of the base station 200 is usually installed on a rooftop of a building or the like where a person does not normally enter, so that the above-mentioned accident or the like is encountered. Since the environment is difficult and the risk of lowering the C / I value is extremely low even when different polarizations are used, FIG.
It is assumed that different polarizations are used according to the frequency plan shown in FIG.

By the way, in such a point-multipoint (P-MP) system, after the operation of the system is started, the base station 200 may be increased due to the expansion of the service area or the increase in the number of the subscriber radio stations 100. Conceivable.
Here, when the base station 200 is added, the other base station 2
2 to prevent interference with the subscriber station 100 and the subscriber radio station 100, FIG.
After deciding the frequency allocation according to the frequency plan as described in FIG. 5, the base station 200 is installed. Here, since the addition of the base station 200 needs to be performed promptly after the determination of the addition, it is necessary that the radio frequency can be easily set.

Also, due to the addition of the base station 200, some of the subscriber radio stations 100 are newly added in comparison with the base station 200 with which communication has been performed so far due to the installation position of the subscriber radio station 100 and the like. There may be a case where it is better to change to perform communication with the base station 200. In this case, it is necessary to change the frequency used by the subscriber station 100.

In view of this point, in the third embodiment, when setting or changing the frequency to be used in the base station 200 or the subscriber radio station 100, the used frequency can be changed without replacing the filter component. It is configured. Hereinafter, a case of changing the frequency of the subscriber wireless station 100 will be described as an example, but the same applies to the frequency setting of the base station 200.

FIG. 8 is a block diagram showing the configuration of the subscriber station 100 according to the third embodiment.

Referring to FIG. 8, a subscriber radio station 100 includes a radio device 10 and a terminal device 30. The wireless device 10 includes an antenna 11, an antenna duplexer 12 including a transmission filter unit 123 and a reception filter unit 124, a transmission unit 13 including a transmission mixer 134, and a reception mixer 143.
, A combining / distributing unit 15, a frequency setting signal demodulating unit 16, a local generating unit 17 including a synthesizer 171, a distributor 172, an oscillation controlling unit 173, and the like.

The terminal device 30 is composed of the combining / distributing device 3
1, demodulation unit 32, modulation unit 33, baseband processing unit 3
4. Central processing unit (CPU) 35, memory unit 36, frequency setting signal modulation unit 37, communication processing unit 38, external interface unit (I / F) 39, between CPU 35 and memory unit 36, communication processing unit 38, etc. Is provided with a control bus 40 provided in the controller.

The terminal device 30 can communicate with the external terminal 50 via the communication processing unit 38. In the present embodiment, the external device 50 is a terminal for setting a use frequency,
For example, a personal computer (PC) is used.

Further, the terminal device 30 is connected to, for example, a PC, a telephone (TEL),
It can be connected to a device such as a private branch exchange (PBX) or a transmission line such as a local area network (LAN).

[0108] In the subscriber's radio station 100, the antenna 11 receives and transmits radio waves to and from the base station 200. The antenna duplexer 12 transmits a reception signal corresponding to a radio wave from the base station 200 received by the antenna 11 to the reception unit 14 via the reception filter unit 124, and also transmits a transmission signal from the transmission unit 13 as described later. Transmission filter unit 12
3 to the antenna 11.

The receiving section 14 outputs the output signal from the antenna duplexer 12 to the receiving
7 to a local signal provided from a synthesizer 171 via a distributor 172 to an IF (Intermed
iate frequency) (down-conversion), and further amplifies and outputs the signal converted to the IF frequency.

The combining / distributing unit 15 sends the output signal from the transmitting unit 14 to the terminal device 30. In the terminal station device 30, the output signal from the wireless device 10 is converted by the combiner / distributor 31 into the demodulator 3.
Divided into two and more. The demodulation unit 32 demodulates the output signal from the combiner / distributor 31 and performs baseband processing unit 34
To send to.

The baseband processing section 34 sends out the demodulated signal from the demodulation section 32 to the CPU 35 via the control bus 40, and sends it out to the device connected to the external interface section 39 via the external interface section 39. I do.

The device connected to the external interface unit 39 uses the demodulated signal from the external interface unit 39 to perform a required process according to the function of the device. For example, if the device is a telephone, the demodulated signal is amplified by a receiver amplifier, converted to an acoustic output by a receiver,
Processing such as transmitting to the user as voice is performed.

Also, the user's voice is collected by a microphone, converted into an electric signal, the voice signal is amplified by a transmission amplifier, and output to the baseband processing unit 34 via the external interface unit 39. Is performed.

The audio signal transmitted from the external interface unit 39 is transmitted to the modulation unit 33 through the baseband processing unit 34. The modulation unit 33 modulates the output signal of the baseband processing unit 34 and sends out the modulated signal to the wireless device 10 via the combining / distributing unit 31.

In the radio device 10, the signal transmitted from the terminal device 30 is received by the combining / distributing device 15,
Distribute to

The transmitting section 13 amplifies the output signal from the combiner / distributor 15 and then transmits this signal to the transmission mixer 134
At, a local signal provided from a synthesizer 171 in the local generator 17 via a distributor 172 is mixed, converted from IF to a predetermined transmission frequency (up-conversion), and further amplified to amplify the signal. 12 is output.

In antenna duplexer 12, the signal from transmitting section 13 is output to antenna 11 via transmission filter section 123, and antenna 11 transmits the signal output from antenna duplexer 12 as a radio wave.

During the above operation, the transmitting unit 13 and the receiving unit 14 of the radio apparatus 10 are, for example, 26 GHz, respectively.
Up-conversion processing and down-conversion processing are performed between a radio frequency (RF) of about 70 MHz and an intermediate frequency (IF) of about 70 MHz, and the demodulation unit 32 of the terminal station device 30
And the modulation unit 33 respectively perform demodulation processing and modulation processing using the IF.

The subscriber radio station 100 according to the present embodiment has a function of changing (setting) the used frequency as needed, in addition to the above-mentioned transmission / reception function. As a component for realizing the use frequency changing function, a communication processing unit 38 and a frequency setting signal modulation unit 37 are provided on the terminal device 30 side, and a frequency setting signal demodulation unit 16 is provided on the radio device 10 side. , An oscillation control unit 173 is provided.

Next, the operation of changing the used frequency in the subscriber station 100 according to the present embodiment will be described.

When changing the used frequency in the subscriber's radio station 100, first, the operation of setting the used frequency band is performed from the external terminal 50. By this setting operation, a use frequency setting signal is output from the external terminal 50, and the signal is sent to the CPU 35 through the communication processing unit 38 and the control bus 41.

The CPU 35 holds this signal in, for example, the memory unit 36 and sends it to the frequency setting signal modulation unit 37.

By providing a means (memory unit 36) for holding a use frequency setting signal from the external terminal 50, for example, every time the power is turned on, the CPU 35 reads the contents of the memory, and It is also possible to add a sequence in which the signal is transmitted and the frequency is set each time.

The frequency setting signal modulating section 37 modulates the frequency setting signal based on the setting operation in a predetermined manner, and outputs the modulated signal via the combining / distributing section 31 to the combining / distributing section 15 of the radio apparatus 10.
To send to.

In the radio apparatus 10, the frequency setting signal transmitted from the terminal station apparatus 30 is transmitted to the frequency setting signal demodulation unit 16 by the combining / distributing unit 15. The frequency setting signal demodulator 16 demodulates the frequency setting signal sent from the combiner / distributor 15 by a predetermined method, and sends out the demodulated frequency setting signal to the antenna duplexer 12 and the local generator 17.

The antenna duplexer 12 includes the transmission filter 1
23 and a plurality of filters (band-pass filters) having different pass bands in the reception filter unit 124, and based on the demodulated frequency setting signal sent from the frequency setting signal demodulation unit 16, Is selected and filter selection switching control for connection to the antenna 11 is performed.

In the local generator 17, the oscillation controller 173 variably controls the oscillation frequency of the synthesizer 171 as an oscillation source based on the demodulated frequency setting signal sent from the frequency setting signal demodulator 16. I do.

As can be seen from this control, in this embodiment, the terminal device 30 is used as a selection signal for a plurality of filters.
Uses a frequency setting signal for setting the oscillation frequency of the frequency synthesizer 171. In this case, since another frequency is not bothersomely used for filter selection control, the configuration can be simplified and the reliability against malfunction can be increased.

The local signal oscillated from the synthesizer 171 by the above control is distributed by the distributor 172 and sent to the transmission mixer 134 in the transmission unit 13 and the reception mixer 143 in the reception unit 14, respectively.

Thereafter, in the subscriber's radio station 100, the frequency selection operation is performed by the corresponding filter in the transmission filter unit 123 and the corresponding filter in the reception filter unit 124, which are switched and connected to the antenna 11, and the local generation unit 17 is newly added. By performing the frequency conversion processing (up-conversion and down-conversion) based on the set local signal, it becomes possible to execute wireless transmission and reception associated with a frequency change according to the operation frequency setting operation of the external terminal 50.

Next, the filter selection operation in antenna duplexer 12 will be described in more detail.

FIG. 9 shows the subscriber radio station 100 in FIG.
FIG. 2 is a block diagram showing a detailed configuration of the antenna duplexer 12 of FIG. This antenna duplexer 12 has a circulator 12
1, changeover switches 122-1, 122-2, 122-
3, 122-4, a transmission filter unit 123, and a reception filter unit 124.

The transmission filter section 123 has band pass filters 123 having different frequency pass band characteristics.
a, 123b, and 123c. Similarly, the reception filter unit 124 includes bandpass filters 124a, 124b, and 124c having different frequency passband characteristics, respectively.
Consists of

The changeover switches 122-1 and 122-2 are
The cooperative operation is performed based on the frequency setting signal sent from the frequency setting signal demodulation unit 16, and one of the filters 123 a, 123 b, and 123 c in the transmission filter unit 123 is placed in the transmission path to the circulator 121. A filter selection operation is performed so as to interpose.

Similarly, changeover switches 122-3, 122
-4 operates in cooperation with each other based on the frequency setting signal sent from the frequency setting signal demodulating unit 16, and switches any one of the filters 124 a, 124 b, and 124 c in the receiving filter unit 124 from the circulator 121. A filter selection operation is performed so that the filter can be inserted into the reception path.

In the antenna duplexer 12, the filter selection operation by the changeover switches 122-1 and 122-2 and the filter selection operation by the changeover switches 122-3 and 122-4 are transmitted from the frequency setting signal demodulation unit 16. The transmission filter unit 123,
The reception filter unit 124 is implemented in such a manner that any one of the transmission / reception filters A, B, and C included therein is selected by a transmission / reception set.

FIG. 10 is a diagram showing the filter characteristics inside the duplexer 12 in FIG. Particularly, FIG. 11A shows filters 123 a and 123 in the transmission filter unit 123.
b and 123c, respectively, which can pass the frequency signals of the transmission band a, the transmission band b, and the transmission band c, respectively.

FIG. 13B shows the reception filter section 12.
4 shows the filter characteristics of the filters 124a, 124b, and 124c in FIG.
The frequency signals of the receiving band b and the receiving band c can be passed.

The subscriber radio station 100 provided with the antenna duplexer 12 having the configuration shown in FIG. 9 includes communication means (communication processing unit 38) for communicating with the external terminal 50. The transmission frequency and the reception frequency can be easily changed within the range of the filter characteristics shown in FIG.

In such a configuration, by performing a characteristic test in all frequency bands in advance, even after the subscriber radio station 100 has been manufactured, it is possible to respond to the request for changing the used frequency. It is not necessary to perform operations such as disassembly of the user wireless station 100 and replacement of filter parts, and it is possible to divert without performing a new frequency characteristic test.

In the third embodiment, three filters (see FIG. 9) are prepared for both transmission and reception, and the selected band is given the characteristics shown in FIG. 10. It is not limited to the combination of.

Thus, for example, in the case of a filter configuration having the number of filters and band selection characteristics according to the frequency plan shown in FIG. 2 or FIG.
By simply performing the setting operation of the used frequency from, the frequency arrangement along the same frequency plan can be easily realized.

In the above embodiment, the frequency synthesizer 171 is shared between the transmission system and the reception system. However, the frequency synthesizer 171 is provided for each of the transmission system and the reception system, and the oscillation frequency variable setting control is performed. It may be performed independently.

In the above embodiment, the control system related to the variable setting of the oscillation frequency of the frequency synthesizer 171 and the control system related to the filter selection in the antenna duplexer are shared, but these control systems are provided separately. (A filter selection control signal for selecting each filter in the transmission filter unit 123 and the reception filter unit 124 is distributed independently of a signal (frequency setting signal) for variably setting the oscillation frequency of the frequency synthesizer 171) You may do it.

As described above, in the third embodiment, in the wireless device 10 of the subscriber wireless station 100, the local oscillator that performs frequency conversion from the intermediate frequency to the wireless frequency is a synthesizer, and the control signal from the terminal device 30 is , The local frequency is variably set, so that when the base station 200 needs to be added due to an increase in the number of the subscriber radio stations 100, the relocation of the base station 200 and the subscriber radio station 100 is extremely easily performed. It becomes possible.

Further, since the radio apparatus 10 is configured to perform frequency selection by selectively switching a plurality of filters having different passband characteristics, the apparatus is disassembled and the filter parts are replaced as in the related art. The frequency can be easily changed using the communication function from the external device 50 without performing a troublesome operation such as the above, and this also contributes to the simplification of the rearrangement of the base station 200 described above.

[0147]

As described above, according to the first aspect of the present invention, an uplink radio channel between a base station and a subscriber radio station is constituted by a radio channel of small capacity and multi-frequency repetition, and a downlink radio channel is formed. The line is configured with a radio channel having a larger capacity and lower frequency repetition than the uplink radio line, and the repetition frequency of the uplink radio line and the downlink radio line is made asymmetric. /
It is possible to increase the transmission capacity of the downlink radio line while making I almost equal, and easily adapt to various communication services, such as Internet services, where the downlink requires a larger transmission capacity than the uplink.

Further, in the second invention, since the up-link radio line is constituted by a radio channel with small capacity and multi-frequency repetition, and the down-link radio line is constituted by a radio channel using different polarization, it can be used. Even if the bandwidth is given as a discrete block, the required C
/ I and transmission capacity can be secured.

In particular, with regard to the arrangement of the uplink, by allocating a plurality of radio channels to each sector, it is possible to secure an appropriate transmission capacity despite the small bandwidth per channel.

In the first and second inventions, the subscriber radio station controls the plurality of band-pass filters in the antenna duplexer to be selectively connected to the antenna, and performs frequency conversion in the transmitting unit and the receiving unit. Control that variably sets the oscillation frequency of the frequency synthesizer that generates the local signal used by using the communication function with the external terminal, without the need for complicated work such as replacing filter parts It is possible to easily cope with a change in the operating frequency of the wireless device of the subscriber radio station, and it is possible to easily realize the rearrangement of the subscriber radio station accompanying the addition of a base station or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a wireless access system according to the present invention.

FIG. 2 is a diagram showing an example of a frequency allocation plan according to the first embodiment.

FIG. 3 is a conceptual diagram illustrating a frequency allocation of a downlink according to the first embodiment.

FIG. 4 is a conceptual diagram showing an uplink frequency allocation according to the first embodiment.

FIG. 5 is a diagram showing an example of a frequency allocation plan according to a second embodiment.

FIG. 6 is a conceptual diagram showing a frequency allocation of a downlink according to the second embodiment.

FIG. 7 is a conceptual diagram showing an uplink frequency allocation according to the second embodiment.

FIG. 8 is a block diagram showing a configuration of a subscriber wireless station according to a third embodiment.

FIG. 9 is a diagram showing a configuration of an antenna duplexer of the subscriber wireless station in FIG.

FIG. 10 is a diagram showing filter characteristics of each filter mounted in the antenna duplexer of FIG. 9;

FIG. 11 is a conceptual diagram showing a state of interference in the wireless access system.

FIG. 12 is a diagram showing a frequency arrangement image in the case of 4-sector, 4-frequency repetition.

[Explanation of symbols]

100, 100-1, 100-2, 100-3, 100
-4,100-11,100-12,100-13,1
00-14 subscriber radio station 10 radio apparatus 11 antenna 12 antenna duplexer 121 circulator 122-1, 122-2, 122-3, 122-4 switch 123 transmission filter section 123a transmission filter A 123b transmission filter B 123c transmission filter C 124 reception filter unit 124a reception filter A 124b reception filter B 124c reception filter C 13 transmission unit 134 transmission mixer 14 reception unit 143 reception mixer 15 combining / distributing unit 16 frequency setting signal demodulating unit 17 local generating unit 171 synthesizer 172 distributor 173 Oscillation control unit 30 Terminal device 31 Combining / distributing unit 32 Demodulation unit 33 Modulation unit 34 Baseband processing unit 35 Central processing unit (CPU) 36 Memory unit 37 Frequency setting signal modulation unit 38 Communication processing unit (CO ) 39 external interface unit (I / F) 40 controls the bus 50 external terminal 200, 200A, 200B, 200C base station 300 communication line 400 switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Oka 3-1-1 Asahigaoka, Hino-shi, Tokyo Inside the Toshiba Hino Factory Co., Ltd. (72) Inventor Takeshi Sawada 1-1-1 Shibaura, Minato-ku, Tokyo F-term in Toshiba head office (reference) 5K067 AA03 AA11 DD27 DD45 EE02 EE10 EE22 EE46 EE61 HH21 HH23

Claims (7)

[Claims] Claims 1. An entire service area is divided into cells.
In a radio access system in which a base station and a plurality of subscriber radio stations that perform point-multipoint communication with the base station by a radio line are arranged for each cell, the radio access system may be arranged in a direction from the subscriber radio station to the base station. The uplink radio line is configured with a radio channel with small capacity and multi-frequency repetition, and the downlink radio line from the base station to the subscriber radio station is repeated with a larger capacity and smaller frequency than the uplink radio line. A radio access system comprising a radio channel according to claim 1, wherein a repetition frequency of the uplink radio channel and the downlink radio channel is asymmetric. 2. A radio access system in which a whole service providing area is divided into cells, and a base station and a plurality of subscriber radio stations for performing point-to-multipoint communication with the base station by a radio line are arranged for each cell. In the system, an uplink radio channel from the subscriber radio station to the base station is configured by a radio channel with small capacity and multi-frequency repetition, and a downlink radio channel from the base station to the subscriber radio station. A radio channel using different polarizations. 3. The radio access system according to claim 2, wherein the inside of the cell is divided into a plurality of sectors, and a plurality of radio channels are assigned to each of the sectors when the uplink is arranged. 4. The subscriber radio station includes a plurality of band-pass filters having different band-pass characteristics, and a changeover switch for switching a connection between the band-pass filter and an antenna in the antenna duplexer. 3. The radio access system according to claim 1, further comprising a filter selection control unit that controls a switch to selectively connect any one of the plurality of band-pass filters to the antenna. 5. A subscriber radio station comprising: a frequency synthesizer for generating a local signal used by a transmitting unit and a receiving unit for performing frequency conversion between an intermediate frequency and a radio frequency; and variably setting an oscillation frequency of the frequency synthesizer. The radio access system according to claim 4, further comprising frequency variable setting control means. 6. A subscriber radio station, comprising: a communication processing unit for performing a communication process with an external device; a frequency setting signal transmitted from the external device via the communication processing unit; Means and signal transfer means for transferring to the frequency variable setting control means, wherein the filter selection control means and the frequency variable setting control means control the filter selection and the oscillation frequency variable setting based on the frequency setting signal. 6. The wireless access system according to claim 5, wherein the wireless access system is performed. 7. The radio access system according to claim 6, wherein the subscriber radio station includes a holding unit that holds the frequency setting signal received from the external device.