JPH10233725A - Wireless local loop system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the wireless local loop(WLL) system where number of accommodate channels is increased at a low cost and the service area is extended by employing antennas with different polarized planes. SOLUTION: The WLL is made up of a base station 10, and lots of stationary station subscriber units 12, 14. Interference capability resistance resulting from the effect of cross polarized wave characteristic (XPD) in the 1st and 2nd stationary station subscriber units 12, 14 is enhanced by providing a horizontally polarized wave antenna 13 and a vertically polarized wave antenna 15 whose polarized planes differ from each other and number of accommodated channels is increased. Furthermore, a diversity effect is obtained through the provision of the two polarized wave antenna and the service area is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a wireless local loop system.

[0002]

2. Description of the Related Art Various multiplexing methods have been proposed as a method for increasing the number of lines accommodated in a wireless local loop (WLL) system or mobile communication. In the field of digital communication in recent years, there are TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access) and the like. FIG. 5 is a conceptual diagram of conventional CDMA. In CDMA, multiple users realize the multiple access by using the same frequency and performing spectrum spreading using different spreading sequences (codes).

[0003]

However, since highly accurate transmission power control for eliminating the bias of the received signal power and RAKE reception for obtaining the path diversity effect are performed, a very expensive system is required. Become. Also, there is a limit to increasing the number of multiplexes, and this is a major problem for WLL which aims to construct a telephone line at a lower cost than a wired line.

[0004] Therefore, an object of the present invention is to provide a WLL that has high interference resistance and can increase the number of accommodated lines at low cost.

[0005]

A wireless local loop system according to claim 1, wherein one of the fixed station subscriber units has a horizontally polarized antenna or a vertically polarized antenna, and the one fixed station subscriber unit is connected to the fixed station subscriber unit. The other adjacent fixed station subscriber unit has a vertically polarized antenna or a horizontally polarized antenna antenna.

In the wireless local loop system according to the present invention, the antennas of the base station are the same polarization antennas as the antennas of the fixed-station subscriber units facing each other.

[0007] In the wireless local loop system according to the third aspect, one fixed station subscriber unit has both a horizontally polarized antenna and a vertically polarized antenna.

A wireless local loop system according to a fourth aspect includes a right-handed polarized wave antenna and a left-handed polarized wave antenna.

[0009]

According to the first to fourth aspects of the present invention, the effect of XPD (cross-polarization characteristics) can increase the interference resistance and increase the number of accommodated lines.

An embodiment of the present invention will be described below with reference to the drawings. 1, 2, 3, and 4 are configuration diagrams of a WLL system according to an embodiment of the present invention. In FIG. 1, 10 is a base station, 11 is an omni-directional omni-antenna connected to the base station 10, 12 is a first fixed station subscriber unit, 13 is connected to a first fixed station subscriber unit 12. , A reference numeral 14 denotes a second fixed station subscriber unit; and 15, a vertical polarization antenna connected to the second fixed station subscriber unit 14. First, the base station 10 is installed at the center in the designed cell, and the omni antenna 11 is omnidirectional, so when communicating with the fixed station subscriber unit,
At the same radius in the cell, the transmission / reception level is almost the same level.

Next, the first fixed station subscriber unit 12 and the second fixed station subscriber unit 14 usually use directional antennas to supplement the transmission / reception level. In the present invention, adjacent fixed station subscriber units are used. Are characterized in that their polarization planes are different from each other. Due to the effect of the XPD (cross polarization characteristics) due to the different polarization planes, even if the fixed station subscribers accommodated in the WLL increase and become very close, for example, the first fixed station subscriber unit 12 The effect of the radio waves transmitted by the second fixed station subscriber unit 14 on the second fixed station subscriber unit 14 is higher than that of a system using an antenna having the same polarization plane.
D (10 to 20 dB). Therefore, it is possible to increase the number of fixed station subscriber units in the cell.

FIG. 2 is an example showing a case where the number of fixed station subscriber units is small. The horizontal polarization antenna 13 and the vertical polarization antenna 15 and the base station 10 can secure sufficient isolation through a multistage Y circulator.
Now, when the base station 10 and each fixed station subscriber unit perform communication, for example, when the first fixed station subscriber unit 12 performs communication, the interference avoidance capability between the fixed station subscriber units has been described with reference to FIG. As in the case of FIG.
This has the effect of reducing incoming radio waves from zero. For example,
When the base station 10 and the first fixed station subscriber unit 12 are communicating, unnecessary incoming radio waves from the base station 10 received by the second fixed station subscriber unit 14 are reduced by the effect of the XPD. Will be done. In this case, since the directional antenna is also used for the base station 10, there is also an effect of reducing the transmission output of the base station 10.

FIG. 3 shows an example in which one fixed station subscriber unit is provided with two antennas, a horizontal polarization antenna and a vertical polarization antenna. This means that the first fixed station subscriber unit 12 will have 2 polarizations regardless of the polarization plane of the adjacent fixed station subscriber unit or the mobile terminal 16 is nearby.
By switching between antennas having two different polarization planes, the anti-interference capability can be increased.

FIG. 4 shows the horizontal polarization antenna 1 shown in FIG.
This is an example in which a right-handed polarized wave antenna 17 is used in place of 3 and a left-handed polarized wave antenna 18 is used in place of the vertical polarization antenna 15.

In this case, as in the case of FIG. 1, it is possible to construct a WLL system having high anti-interference ability by the effect of XPD. Similarly, the antennas shown in FIGS. 2 and 3 can be right- and left-handed polarization antennas instead of the horizontal and vertical polarization antennas.

[0016]

As described above, according to the present invention, by using antennas having different polarization planes, it is possible to construct a WLL system having high interference resistance due to the effect of XPD (cross polarization characteristics).

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a WLL system according to an embodiment of the present invention;

FIG. 2 is a configuration diagram of a WLL system according to an embodiment of the present invention;

FIG. 3 is a configuration diagram of a WLL system according to an embodiment of the present invention;

FIG. 4 is a configuration diagram of a WLL system according to an embodiment of the present invention;

FIG. 5 is a conceptual diagram of conventional CDMA.

[Explanation of symbols]

 Reference Signs List 10 base station (CS) 11 omni antenna 12 first fixed station subscriber unit 13 horizontal polarization antenna 14 second fixed station subscriber unit 15 vertical polarization antenna 16 mobile terminal (PS) 17 right-handed polarization antenna 18 Left-handed polarized antenna

Claims (4)

[Claims] 1. One fixed station subscriber unit has a horizontally polarized antenna or a vertically polarized antenna, and the other fixed station subscriber unit adjacent to the one fixed station subscriber unit has a vertically polarized antenna or a vertically polarized antenna. A wireless local loop system having a horizontally polarized antenna. 2. The wireless local loop system according to claim 1, wherein the antenna of the base station is the same polarization antenna as that of the opposing fixed station subscriber unit. 3. The wireless local loop system according to claim 1, wherein one fixed station subscriber unit has both a horizontally polarized antenna and a vertically polarized antenna. 4. The wireless local loop system according to claim 1, further comprising a right-handed polarization antenna and a left-handed polarization antenna.