JPH0618335B2 - Base station receiver - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station receiver used for mobile communication, rural communication and the like.

Configuration of Conventional Example and Problems Thereof FIG. 1 (A) shows a conventional base station receiver for mobile communication, in which a hexagonal cell with an omnidirectional antenna is divided into three rhombic sectors by a directional antenna. An angle diversity receiver with two units is shown.

Conventionally, a base station uses an omnidirectional antenna, and the most efficient wireless cell (hereinafter referred to as a cell) is a hexagon, and the hexagon fills the communication area. When a mobile station tries to connect communication of a low power device such as a portable radio telephone to a vehicle designed to balance the mobile transmission output and the base transmission output like an automobile telephone, it is transmitted when trying to connect like a car. The effective radiated power (ERP) is 10 to 15 dB lower due to the difference in power and the difference in antenna gain.
The S / N deterioration due to external noise is reduced by using the base receiving antenna as a directional antenna. However, since the improvement of the S / N ratio by the directional antenna is about 6 to 7 dB with the 120 ° directional antenna, the S / N improvement effect of 6 to 7 dB is further added by the base station diversity reception and the communication with the car telephone is improved. We try to get equivalent call quality.

As shown in FIG. 1 (B), the shape of the sector by the conventional 120 ° directional antenna has six vertices (P) of the above hexagonal cell.
The directivity of the antenna is set so that the hexagonal cells form a rhombic sector by a line connecting to the center of every other hexagon. In this case, the directivity angle of the normal directional antenna is defined by the half-width (-3 dB) point, but it is necessary to have the maximum gain for the diamond-shaped acute-angled portion divided as described above.
Therefore, the full width at half maximum of the antenna gain needs to be sufficiently larger than 120 °, which lowers the antenna gain and relatively increases the external noise. Further, since the improvement effect due to the angle diversity is obtained in many shaded areas where two or more antennas overlap, there is a drawback that the S / N improvement effect due to the diversity cannot be obtained in the front direction (F) of the 120 ° antenna. This is the same when the cell is divided from 3 to 6, and it is difficult to obtain the effect of improving diversity for the communication area in the direction of the directivity.

The object of the present invention is to eliminate the drawbacks of the above-mentioned conventional example, and to surely use the angle and the space diversity together to ensure the S / N.
It is an object of the present invention to realize a base station receiving device that can obtain an improvement effect.

In order to achieve the above object, the present invention divides a hexagonal communication area into three flat or rhombic areas to reduce the influence of external noise, and includes an omnidirectional antenna at different installation positions. And the improvement effect by space diversity is obtained.

Description of Embodiments A configuration of an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, a base station is provided in the center of the hexagonal cell as shown in (B) to (D), and the hexagonal radio cell is divided into three flat pentagonal or rhombic sectors. Directional antennas A ₁ , A ₂ , and A ₃ having an opening angle of 120 ° are used. A ₀ is an omnidirectional antenna, which is also used as a base station transmission antenna. Further, as shown in FIG. 2 (C), the height and the installation position of the antenna device are different.

In FIG. 2 (A), reference numerals 1, 2 and 3 are communication receivers, which represent specific one channel of a base station having N channels. Further, 11,21,31 are inputs of the respective receivers, 12, 22, 32 are outputs of voices of the respective receivers, 1
Reference numerals 3, 23, and 33 are outputs of reception level signals proportional or inversely proportional to the reception input electric field level of each receiver. In the reception level signal, a large portion of the reception input has a substantially dB straight line, and it is desirable that this output be linear up to a portion where the reception input electric field level is low. Reference numeral 4 denotes an antenna switch, which switches and connects three directional antennas and omnidirectional antennas to each of the three receivers. The switching of the antenna is controlled by the reception mode controller 6. S ₁₀ , S ₁₁ , S ₁₂ , and S ₁₃ are switches that connect any _{one of} the omnidirectional antenna A ₀ and the directional antennas A ₁ , A ₂ , and A ₃ to the receiver 1. Similarly, S ₂₀ , S ₂₁ , S ₂₂ , and S ₂₃ are receivers 2, S ₃₀ , S ₃₁ , and
S ₃₂ and S ₃₃ are switches connected to the receiver 3. Reference numeral 5 denotes a level comparator of the reception level (instantaneous value) of each receiver, which determines the receiver having the highest reception level among the three receivers. Reference numerals 51, 52 and 53 are reception level signal inputs from the respective receivers, and 54 is an information output indicating the receiver having the highest reception level. Reference numeral 6 denotes a reception mode controller that connects the receiver and the antenna, and calculates the time average value from the reception level (instantaneous value) of each receiver given from 61, 62, 63, and the antenna switching device according to the control flow described later. Control 4 Reference numeral 64 is a switching control signal output of a combination of each receiver and each antenna. 7 is a voting section, and 7
1, 72 and 73 are inputs such as received voices from the receivers 1, 2 and 3, 74 is input of information indicating the receiver of the highest reception level from the level comparator 5, and 75 is a voting output, One of the inputs 71, 72, 73 is selected by the input 74 and is connected to the HYB circuit of the mobile telephone switching center (MTSO). Although the communication system from the base station to the mobile station and the control system from the MTSO to the reception mode controller are omitted in FIG. 1, the public car telephone system (electric power system in Japan, AMPS system in overseas), other It can be used in combination with a base station transmission device for press talk communication.

Next, the operation of the reception mode controller 6 for obtaining the improvement effect in the above embodiment will be described with reference to the flowchart of FIG.

In the standby state, the three receivers ₁ , ₂ and ₃ control the antenna switch 4 so as to connect to the directional antennas A ₁ , A ₂ and A ₃ , respectively.

Step 1 will be described with reference to the flowchart of FIG.
It is checked whether or not there is an input at 01, and when the input is detected, it is started. Next, in step 102, input levels in three directions are measured. In step 103, it is determined whether or not the input is equal to or more than the threshold, and when it is above, the determination is YES. If NO, the process returns to step 102 to continue the reception in the three directions.
If YES, the routine proceeds to step 104, where it is judged whether or not there is one direction. If NO, the process proceeds to step 105, where the antenna with the highest reception input and the next highest antenna are selected, and the above three communication receivers are connected to the omnidirectional antenna and a total of three antennas. If YES, the process proceeds to step 106, and three receivers are connected to the input antenna, one of the two non-input antennas, and the omnidirectional antenna A ₀ . Next, in step 107, it is determined whether or not there is a non-input antenna. NO
In the case of, the process proceeds to step 108 and the change of the highest input antenna is monitored. Step 107,
If YES is obtained, the t-second timer in step 109 is advanced. In step 110, it is determined whether t seconds have elapsed. If YES, the t-second timer is cleared in step 111, and the antenna of the receiver with the lowest received input is switched and connected in step 112 to measure the input of the antenna other than the antenna in use. In step 113, it is determined whether the level is higher than the previous level. If the determination result is NO, the process returns to step 107, the measurement result is determined again, and this loop is repeatedly executed. If there is an antenna higher than that before the measurement in step 113, the process returns to the determination in step 104 and the first loop is repeatedly executed. According to the above operation, at least two call receivers are connected to the antenna A ₁ ,
Diversity reception is performed by connecting one to each of A ₂ , A ₃ and A ₀ .

In addition, by comparing the reception level of the receiver with the level comparator, the demodulation output is voted to cope with the instantaneous fluctuation of the reception level, and the switching controller connects to the receiver of the four antennas. Since the antennas can be selected and the connected antennas can be switched sequentially even if the level fluctuations due to the movement of the moving body are switched, it is always suitable for three receivers that are less than the total number of antennas. It has an advantage that antenna selection can be performed.

EFFECTS OF THE INVENTION The present invention is configured as described above, and has the following effects. That is, the omnidirectional antenna has been conventionally used for base station transmission, and by sharing the antenna with the transmission / reception sharing device, angle diversity reception and space diversity reception with the omnidirectional antenna are performed, and a call is made. There is an advantage that quality improvement can be implemented economically.

[Brief description of drawings]

1 (A) and 1 (B) are block diagrams of a conventional base station receiver and a diagram showing the configuration of a wireless cell, and FIGS. 2 (A) to (D) are one embodiment of the base station receiver of the present invention. FIG. 3 is a block diagram of an example and a diagram showing a configuration of a wireless cell, and FIG. 3 is a flowchart diagram of antenna switching. A ₁ , A ₂ , A ₃ ... Directional antenna, A ₀ ... Omnidirectional antenna, 1, 2, 3 ... Call receiver, 4 ... Antenna switch, 5 ... Reception level comparator, 6 ... ... Reception mode controller, 7 ... Boating section.

Front page continued (72) Inventor Kazuo Nagao 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd. (72) Nobuyoshi Ito 4--3 Tsunashima-east, Kohoku-ku, Yokohama, Kanagawa No. 1 in Matsushita Communication Industrial Co., Ltd. (56) Reference JP-A-59-72831 (JP, A)

Claims (1)

[Claims] 1. A horizontal plane is divided into three fan-shaped areas.
When the directional antennas and the omnidirectional antenna in the horizontal plane are selectively switched to and received by three wireless receivers, which are less than the total number of antennas, through antenna switches, the reception levels of the respective receivers are compared. A reception level comparator and a switching controller for switching the antenna switch based on the reception level information of the comparator are provided, and the switching controller controls two directional antennas having a high inner level of the three directional antennas. Is controlled to connect to each of the receivers one by one together with an omnidirectional antenna, and the reception level comparator outputs the highest level output of the demodulated outputs of each receiver. A base station receiver adapted to selectively output by.