JPH01202935A - Space diversity reception system - Google Patents

Abstract

PURPOSE:To minimize the reduction of a reception level by arranging a 1st antenna and a 2nd antenna applied to the diversity reception at an interval V in the perpendicular direction and at an interval H in the horizontal direction. CONSTITUTION:The antennas 1, 2 are arranged at an interval V in the perpendicular direction and at the interval H in the horizontal direction. In the case of propagation of line-of-sight, the reduction in the reception input level caused due to a phase difference between a reflected wave on sea and a direct wave is minimized by selecting two reception signals obtained from the two antennas 1, 2 placed in the vertical position (interval V) being an odd number of multiple of a half pitch of a height pattern. In the case of propagation of over the horizon, the reduction in the reception input level is minimized by selecting two reception signals of a different propagation path obtained from the two antennas 1, 2 placed in the horizontal position (interval H). Thus, the diversity reception corresponding to the propagation of line-of-sight and over the horizon is obtained in the microwave communication line having such two propagation states.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to diversity reception applied to microwave communication lines, and more particularly to a space diversity reception system equipped with two antennas used for diversity reception.

[Conventional technology]

Conventionally, this type of space diversity reception (Rt method) has been used, for example, in microwave communication lines where the distance between islands is around 11001a, and when the normal equivalent earth radius coefficient K = 4/3, As shown in Figure 3 (a), if line-of-sight propagation occurs, the equivalent earth radius coefficient = 273
When the distance is 1, the propagation occurs outside the line of sight as shown in Figure 3 (b). Therefore, in line-of-sight microwave communication lines, two antennas for diversity reception are placed at a predetermined distance in the vertical direction in order to avoid instantaneous line interruptions due to reflected waves. On the other hand, in non-line-of-sight microwave communication lines, two antennas for diversity reception are placed at a predetermined distance in the horizontal direction in order to obtain received signals with as little correlation as possible as a countermeasure against line fading.

[Problem to be solved by the invention]

In the conventional space diversity reception method described above, two antennas are placed with a predetermined interval in the vertical or horizontal direction, so it is expected that diversity reception will only be effective in either line-of-sight propagation or non-line-of-sight propagation. The drawback is that it cannot be done.

[Means for solving problems]

In the space diversity reception system according to the present invention, a first antenna and a second antenna used for diversity reception are arranged at an interval V in the vertical direction and an interval H in the horizontal direction.

[Effect]

According to the present invention, even if the radio wave propagation situation becomes line-of-sight propagation (1) non-line-of-sight propagation, it is possible to minimize the decrease in reception level.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a space diversity reception system according to the present invention.

In the same figure, 1 and 2 are a first antenna and a second antenna 3a and 3b arranged with a vertical interval of V and a horizontal interval of H, as shown in the detailed front view of FIG. 4 is a receiving device, and 4 is a combining device.

Next, we will explain the operation of the space diversity reception system with the above configuration. First, in the case of internal propagation, the reception input level decreases due to the phase difference between the reflected wave from the ocean and the direct wave (instantaneous interruption). (including fading) by selecting two received signals obtained from two antennas 1 and 2 placed at upper and lower positions (interval V) that are odd multiples of the half pitch of the hide pattern. can be kept to a minimum. On the other hand, in the case of non-line-of-sight propagation, short-period deep fading (fluctuations in received input level) always occurs, but if the radio wave propagation path differs, the correlation of the fading becomes smaller (that is, the fading pattern differs). The reduction in the reception input level is minimized by selecting two reception signals with different propagation paths obtained from the two antennas 1 and 2 placed at horizontal positions (distance H). It can be suppressed.

〔Effect of the invention〕

As explained in detail above, according to the space diversity reception method according to the present invention, diversity reception corresponding to each of the two propagation conditions, line-of-sight propagation and non-line-of-sight propagation, can be obtained in a microwave communication line. effective.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an embodiment of the space diversity receiving system according to the present invention, FIG. 2 is a diagram showing the arrangement of the two antennas shown in FIG.
) is a diagram showing the difference in radio wave propagation conditions for each equivalent earth radius coefficient K. 1 and 2: antenna, 3m and 3bφ: self-receiving device, 4: combining device. Patent applicant: NEC Corporation

Claims (1)

[Claims] In microwave communication lines where the radio wave propagation status changes to line-of-sight propagation or non-line-of-sight propagation due to variations in the equivalent earth radius coefficient K, the first and second antennas used for diversity reception are vertically connected. spacing V in the direction
A space diversity reception method characterized in that the antennas are arranged at intervals of H in the horizontal direction.