JP2002191069A - Wireless base station layout method for internet service - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless base station layout method for an Internet service by reducing interference between signals of base stations so as to improve the throughput of the entire system. SOLUTION: As a spread system of wireless base stations, a plurality of and preferably 19 sets of wireless base stations adopting the frequency hopping system are selected as one basic unit and laid out in a plane as shown in Fig. Furthermore, 19 kinds of hopping sequence numbers are respectively assigned to each of the 19 wireless base stations. Thus, the wireless base stations laid out in a plane do not output the same hopping frequency at any time. As a result, interference between the wireless base stations is reduced to enhance the throughput of the entire system. Thus, this invention provides the layout of the wireless base stations for the Internet service where the base stations are consecutively arranged in a plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for arranging radio base stations for Internet service, and more particularly, to arranging radio base stations of a frequency hopping system in a planar manner, so that the area covered by the radio base station is continuous in a planar manner. And a method of arranging wireless base stations for Internet services.

[0002]

2. Description of the Related Art In a conventional base station for mobile communication or the like, when base stations are arranged two-dimensionally, different frequencies are allocated to neighboring base stations to avoid interference between the base stations and to provide a sufficient distance. , The base station that uses the same frequency repeatedly to achieve efficient use of frequency resources, ie, F
The DMA method is used. If this FDMA scheme is applied to the arrangement of wireless base stations for Internet services, the following is considered.

[0005] FIG. 15 is a diagram showing a frequency allocation in the direct spread system (DS system) of the 2.4 GHz band wireless LAN device. In order to prevent the frequency bands from overlapping each other, the frequency of three channels, that is, the frequency of three channels, is used. , The first, sixth, and eleventh channels can be used. The horizontal axis indicates frequency.

FIG. 16 is a diagram showing an example in which base stations to which the frequencies of the three channels are assigned are two-dimensionally arranged so as to minimize signal interference between the base stations. As shown in the figure, the coverage area of the base station to which the frequency of channel 1 has been allocated includes its upper, lower, left, and right sides.
It is arranged so that it is surrounded by the coverage area of the base station to which the frequencies of channels 6 and 11 are assigned, and the coverage area of the base station to which the same frequency of channel 1 is reappears outside the surrounding area. Incidentally, the radius of the cover area is approximately 100 m to 600 m.

[0005] In the mobile communication and the like, as another method, a method of allocating the same frequency to a plurality of base stations and classifying the signals by a spreading code of a directly spread signal, that is, a CDMA method is used. . Further, as still another method, each base station uses the same frequency and emits a burst-shaped radio wave at different timings, thereby separating signals temporally, that is, TDM.
The A method has also been proposed.

[0006]

However, FIG.
5. In the conventional method described with reference to FIG. 16, since the distance between base stations to which the same frequency is assigned is short, if the base stations transmit signals at the same time, signal interference occurs and the throughput of Internet communication decreases. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of arranging radio base stations for Internet service which can solve the above-mentioned problems of the prior art, reduce signal interference between base stations, and improve the overall system throughput. To provide.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for arranging radio base stations for an Internet service so that the coverage area of the radio base stations is continuously and widely developed. Has a first feature in that a frequency hopping method is used as a spreading method of the radio base station.

Further, the present invention develops one or more units of a cover area having 19 wireless base stations as a basic unit, and assigns 19 types of hopping sequence numbers to each of the 19 wireless base stations. Has a second feature in that each of them is allocated so as to be mutually dispersed.

According to the first and second features, since the adjacent radio base stations do not output the same hopping frequency at any time, interference between the radio base stations is reduced. As a result, the throughput of the entire system can be improved.

A third feature of the present invention resides in that a radio base station of a direct spreading system is arranged in a coverage area of the radio base station. According to this feature, when performing direct spreading communication, high-speed signal transmission becomes possible, and it becomes possible to satisfy the needs of users who desire high-speed communication.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. First, a frequency hopping method (FH method: spread spectrum frequency hopping), which is one of the spread spectrum methods used in the present invention, will be briefly described. FIG. 1 is a block diagram showing a schematic configuration of a transmission side and a reception side device of the frequency hopping system.

The transmitting device converts the input signal to primary modulation (PS).
K, FSK, etc.), a secondary modulator 2 for secondary-modulating (spreading) the primary-modulated signal, and a frequency converter 3 for converting the secondary-modulated signal to a radio frequency
And an antenna 4. The secondary modulator 2 includes an HP (hopping) signal generator 2a, a frequency synthesizer 2b, and an adder 2c.

On the other hand, the receiving apparatus includes an antenna 11, a frequency converter 12 for frequency-converting a received signal, a secondary demodulator 13 for secondary demodulation (despreading) of a signal, and extracting a specific frequency band. And a primary demodulator 15. Further, the secondary demodulator 13
Is a synchronizing signal extractor 13a, a frequency synthesizer 13
b and an adder 13c.

The frequency synthesizers 2b and 13b operate synchronously and, as shown in FIG. 2, use a predetermined hopping pattern A to separate a signal of a specific frequency with time and discretely. Output. The adder 2c
Adds the signal modulated by the primary modulator 1 and the signal from the frequency synthesizer 2b to obtain the frequencies B1, B2,... Of the narrow-band modulated signal as shown in FIG.
, Bm,..., Bn are sequentially switched and output. Since the frequency is switched at a high speed, the frequency spectrum appears to be spread.

FIG. 4 is a timing chart of the signal B output from the adder 2c, wherein the horizontal axis represents time and the vertical axis represents frequency. As shown, the frequency of signal B switches every t seconds.

In the present invention, the frequency hopping method is adopted as a spreading method for a radio base station, so that the coverage area of the radio base station is continuously and planarly developed. One embodiment of the planar arrangement according to the present invention will be described with reference to FIG.

As shown, in this embodiment,
Hopping sequence (hereinafter referred to as HS) number 0,
3,6,9,12,15,18,21,24,27,3
Nineteen radio base stations to which nineteen types of 0, 33, 36, 39, 42, 45, 48, 51, and 54 are assigned constitute a basic unit area coverage area.

FIG. 6, FIG. 7, and FIG. 8 are explanatory diagrams of an example of the content of the HS number. The HS number (No.)
The pattern number is written in the vertical direction. The numerical value α of the region surrounded by the horizontal direction and the vertical direction is (2400+
α) Indicates hopping frequency in MHz. From the figure, for example, hopping pattern 1 is
2402MHz, 2405MHz, ..., 2477MHz
Output the hopping frequency of Similarly, hopping pattern 2 has 2425 MHz for HS numbers 0 to 75.
The hopping frequencies of z, 2428 MHz,..., and 2421 MHz are output. FIGS. 6 to 8 show ISO / IE
C 8802-11.

Also, from these figures, in this embodiment,
Although it can be seen that 79 types of hopping patterns can be obtained, in the present invention, it is possible to use some of the 79 types of patterns instead of using all of them. In addition, H used in the wireless base station arranged in the plane in FIG.
As the S number, 19 types are selected from 26 types of the HS numbers 0 to 75.

Considering FIG. 5 and FIGS. 6 to 8 together,
Since the 19 radio base stations in FIG. 5 do not output the same hopping frequency at any time, the interference between the radio base stations can be reduced and the throughput of the entire system can be improved. Become. Further, even if an interference wave (noise or the like) exists at a specific frequency, the frequency of the radio base station hops to another frequency in a short time t,
It is possible to provide a system that is less affected by the interference and is resistant to the interference.

FIG. 9 is a conceptual diagram of a radio base station arranged in the area described in FIG. 5, and includes nineteen radio base stations 20A.
-20N are arranged in a plane as shown in FIG.
Installed on the roof of a building. In the example of FIG. 9, each of the wireless base stations 20A to 20N is connected by a loop-shaped optical fiber cable 20, and each of the wireless base stations 20A to 20N
0N radiates signals from omnidirectional antennas 22A to 22N connected via coaxial cables 21A to 21N. The radiated signal is received by the antenna 32 of the subscriber station and transmitted to the personal computer (PC) 34 via the radio 33. Both ends of the looped optical fiber 20 are connected to a center station 41 and further connected to the Internet.

FIG. 10 shows a configuration in which a plurality of unitary planar cover areas described in FIG. 5 are integrated to form a wider planar cover area. In the illustrated example, three basic units are integrated, but the present invention is not limited to this, and a larger number of basic units may be integrated to form a wider area.

FIG. 11 is an explanatory diagram of the second embodiment of the present invention. In this embodiment, an HS number that is not used in the basic unit, for example, HS. The wireless base station to which 57 is assigned is arranged. In this way, radio waves reach the dead zone area, the area where communication is not possible is eliminated, and the frequency used in the dead zone is the same as the frequency used in the surrounding area. Therefore, interference from other base stations can be minimized, and base stations can be added to the dead zone.

FIG. 12 is a diagram showing a third embodiment of the present invention. In this embodiment, when the traffic in the area where the radio base station is already installed increases, the existing radio base station is installed. A wireless base station to which an HS number that has not been used in the area coverage area of the basic unit is additionally arranged in the area. According to this embodiment, interference from other base stations can be minimized, and a wireless base station can be additionally arranged in an area with a large traffic.

FIG. 13 is a diagram showing a fourth embodiment of the present invention. In this embodiment, a radio base station DS of a direct sequence system is arranged in a two-dimensional coverage area formed by the frequency hopping method described with reference to FIGS. 5 and 10 and covered by the radio base station DS. It is characterized in that the communication speed of the subscriber station is higher than that of the subscriber station covered by the frequency hopping method. The direct spreading method has a feature that high-speed signals can be transmitted, although an area cannot be secured by installing a base station so as to have a continuous surface. Therefore, the subscriber of the wireless base station can secure a high-speed access line.
In this case, a directional antenna is preferably used for the radio base station DS so that radio waves can reach only a limited range.

In order to reduce interference with the frequency hopping type radio base station, the radio base station DS is preferably installed at a relatively low position such as the height of an intermediate portion of a telephone pole. In general, the antenna of the radio base station of the frequency hopping system is installed at a place about 12 m above the ground, so that the antenna of the radio base station DS is preferably installed at a place about 5 m above the ground.

Further, as shown in FIG. 14, it is preferable that the frequency band used by the radio base station DS is set to a frequency band which is about one third of the frequency band used by the radio base station of the frequency hopping system. is there. By doing so, the throughput of communication using the radio base station of the frequency hopping scheme and the direct spreading scheme is slightly reduced, but both types of services can be provided in parallel in almost the same area. .

[0029]

As is apparent from the above description, according to the present invention, since the frequency hopping method is employed as the spreading method of the radio base stations, the plurality of radio base stations arranged in a plane can determine at what time. In this case, the same hopping frequency is not output. For this reason, it is possible to provide a wireless base station arrangement for Internet service that is continuously and spatially developed, which can reduce signal interference between wireless base stations and improve the throughput of the entire system.

Further, a radio base station to which a hopping sequence number other than 19 hopping sequence numbers is allocated is located in a zone where radio waves are insensitive to the coverage area of the radio base station or in a zone where the communication amount has increased to a predetermined value or more. As a result, Internet services can be sufficiently used for subscriber stations residing in these zones. In addition, the Internet service for all subscriber stations becomes uniform, and the fairness of the service can be achieved.

Further, by arranging the radio base station of the direct spreading system in the coverage area of the radio base station adopting the frequency hopping system, it is possible to sufficiently satisfy the demand for the user who wants to transmit a high-speed signal. Can be satisfied.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmitting side and a receiving side of a frequency hopping scheme used in the present invention.

FIG. 2 is an explanatory diagram of a hopping pattern output from a frequency synthesizer.

FIG. 3 is a spectrum diagram of a spread signal.

FIG. 4 is an explanatory diagram of frequency hopping.

FIG. 5 is an explanatory diagram of a basic unit of a hopping sequence arrangement.

FIG. 6 is a diagram illustrating an example of a hopping sequence.

FIG. 7 is a continuation of FIG. 6;

FIG. 8 is a continuation of FIG. 7;

FIG. 9 is a conceptual diagram of a wireless base station that realizes the hopping sequence arrangement of FIG. 5;

FIG. 10 is an explanatory diagram of a case where a plurality of basic units of a hopping sequence arrangement are integrated to form a cover area.

FIG. 11 is an explanatory diagram when a wireless base station is additionally arranged in a blind zone.

FIG. 12 is an explanatory diagram of a case where a wireless base station is additionally arranged in a zone where the communication volume has increased.

FIG. 13 is an explanatory diagram of a case where a radio base station of a direct spreading scheme is additionally arranged in a cover area formed by a radio base station employing a frequency hopping scheme.

FIG. 14 is an explanatory diagram of a frequency band used by a direct spreading wireless base station in the case of FIG. 13;

FIG. 15 is a diagram showing a frequency allocation in a 2.4 GHz band wireless LAN device in a direct spreading system (DS system).

FIG. 16 is a diagram showing a method for arranging wireless service base stations for the Internet service by the DS system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Primary modulator, 2 ... Secondary modulator, 2a ... HP (hopping) signal generator, 2b ... Frequency synthesizer,
2c, 13c ... adder, 3 ... frequency converter, 4, 1
1, 22A to 22N ... antenna, 13 ... secondary demodulator,
13a: Synchronous signal extractor, 13b: Frequency synthesizer, 14: Band-pass filter, 15: Primary demodulator, 2
0: Loop optical fiber cable, 20A to 20N ...
Radio base stations, 21A to 21N ... coaxial cable, 31 ...
Subscriber station, 41 ... Center station.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kinya Saito 3-8-3 Nishi-Shimbashi, Minato-ku, Tokyo Speednet Co., Ltd. F-term (reference) 5K022 EE04 EE22 EE32 5K067 AA03 AA13 AA21 CC10 EE10 EE45 KK02

Claims (9)

[Claims] 1. The radio base station coverage area is continuously
A method of arranging radio base stations for an Internet service, which is spread over a whole area, wherein a frequency hopping method is used as a spreading method of the radio base stations, wherein . 2. The hopping method according to claim 1, wherein the frequency hopping method includes 19 or more hopping frequency numbers and different hopping frequency numbers assigned to the hopping frequency numbers. A method of arranging wireless base stations for Internet service, comprising a plurality of patterns, wherein the wireless base station to which the hopping frequency number is assigned transmits frequencies in a time series according to the hopping pattern. 3. The method for arranging wireless base stations for Internet service according to claim 1 or 2, wherein one or more units of a cover area having 19 wireless base stations as a basic unit are developed. Allocating 19 types of hopping sequence numbers to each of the wireless base stations so as to be distributed to each other. 4. The method according to claim 2, wherein a hopping sequence number other than the 19 types of hopping sequence numbers is set in a radio wave dead zone in a coverage area of the radio base station. A method of arranging wireless base stations for Internet service, wherein allocated wireless base stations are arranged. 5. The hopping sequence according to claim 2, wherein, when the traffic in the coverage area of the radio base station increases more than a predetermined value, the hopping sequence is added to the increased zone. A method of arranging wireless base stations for Internet service, wherein wireless base stations to which hopping sequence numbers other than the 19 types of numbers are assigned are arranged. 6. The method for arranging wireless base stations for Internet service according to claim 1, wherein a wireless base station of a direct spreading system is arranged in a coverage area of said wireless base station. Wireless base station arrangement method for Internet service 7. The method for arranging wireless base stations for Internet service according to claim 6, wherein:
A method of arranging wireless base stations for Internet services, wherein the frequency band is set to about 1/3 of a frequency band used by the frequency hopping wireless base station. 8. The method according to claim 6, wherein an antenna of the direct-sequence wireless base station is installed at a lower position than an antenna of a frequency-hopping wireless base station. A method of arranging wireless base stations for Internet services, characterized in that: 9. The method according to claim 8, wherein the antenna is a directional antenna.