JP3245439B2 - Antenna selection diversity receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna selection diversity receiver used in radio communication by burst transmission.

[0002]

2. Description of the Related Art A conventional antenna selection diversity receiver of this kind is described in "1991 Autumn Meeting of the Institute of Electronics, Information and Communication Engineers, B-219, September 6, 1991". In wireless communication, there is a period in which received power temporarily decreases due to fading, communication quality deteriorates, and communication becomes impossible. As a method for avoiding this, there is diversity reception. The most frequently used diversity receiver is called a branch selection diversity receiver, which prepares two or more receiving circuits including an antenna and selects a signal having the best reception quality. Since more than one is required, there is a disadvantage that the hardware scale tends to be large. In order to eliminate this drawback, an antenna selection diversity receiver as disclosed in the above-mentioned document has been proposed. This means that although there are two antennas, only one receiving circuit is prepared and the received power is measured twice using each of the two antennas immediately before receiving the burst, and the reception power at each antenna near the center of the burst is measured. The received power is linearly predicted, and reception is performed during this burst using the antenna having the larger predicted received power. Since the antenna selection diversity receiver requires only one receiving circuit, there is an advantage that the receiver can be easily downsized.

[0003]

However, in the conventional antenna selection diversity receiver described above, the antenna to be applied to the entire burst is selected based on the reception power at one point near the center of the burst. In some cases, an erroneous antenna is selected near both ends, and therefore, there is a problem that communication quality cannot be improved as much as a branch selection diversity receiver. Therefore, an object of the present invention is to provide an antenna selection diversity receiver which can be expected to improve communication quality on the order of a branch selection diversity receiver without a large increase in hardware scale.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention measures the received power twice using each of two antennas immediately before receiving a burst, and measures each received power within each burst. The received power at the antenna is linearly predicted, and within a burst, the first antenna uses the first antenna in a portion where the received power is predicted to be stronger, and the second antenna uses the second antenna in a portion where the received power is not predicted. The antenna is selected, and the predicted value of the subsequent power of this antenna is sequentially updated using the received power of the antenna selected at this time, and the subsequent antenna selection is performed based on the updated predicted value. The antenna selection diversity receiver is configured as described above.

[0005]

According to the present invention, since the antenna selection diversity receiver is configured as described above, a correct antenna can be selected with high probability in a burst. Therefore,
The above problem can be solved.

[0006]

1 is a block diagram showing an embodiment of an antenna selection diversity receiver according to the present invention. In FIG. 1, 1 and 2 are antennas, 3 is an antenna switching circuit, 4 is a receiving circuit, 5 is a power measuring circuit, 6 is a control circuit, 7 is a linear prediction circuit, and 8 and 9 are memories. FIG. 2 is a diagram for explaining the operation of the antenna selection diversity receiver according to the present invention. The desired signal is transmitted in a burst period.

First, an operation performed before receiving a burst will be described with reference to FIG. At time t1 immediately before receiving the burst, the power from the antenna 1 is measured. That is, the antenna switching circuit 3 is connected to the antenna 1 side, and the power p1 is measured from the receiving circuit 4 through the power measuring circuit 5. The control circuit 6 stores the power value p1 in the memory 8
To memorize. Next, the time immediately before receiving the next burst
At t2, the power from the antenna 2 is measured. That is, the antenna switching circuit 3 is connected to the antenna 2 side, and the power p2 is measured from the receiving circuit 4 through the power measuring circuit 5.
In the control circuit 6, the power value p2 is stored in the memory 9. Similarly, time t3 immediately before receiving the subsequent burst
And the powers p3 and p4 at t4 are measured and stored in the memories 8 and 9. Thereafter, the control circuit 6 sends the power values p1 and p3 to the linear prediction circuit 7, obtains prediction data for the power of the antenna 1, and stores it in the memory 8. Similarly, the control circuit 6 determines the power value
p2 and p4 are sent to the linear prediction circuit 7 to obtain prediction data for the power of the antenna 2 and stored in the memory 9.

Next, the operation during the burst period will be described with reference to FIG.
This will be described with reference to FIG. In the burst period, first, the control circuit 6 compares the data for the antenna 1 stored in the memory 8 with the data for the antenna 2 stored in the memory 9 and uses the antenna switching circuit to use the larger antenna. 3 is controlled. In the example of FIG. 2, the antenna 1 is used until the intersection point t5 of the two powers, and the antenna 2 is used thereafter. However, this initial prediction is not always correct within a burst. For example, as shown in FIG. 2B, the power of the antenna 1 at time t5 may deviate from the predicted value, such as the power value p5. At this time, in the present invention, the control circuit 6
The current power value p5 and the immediately preceding power value p3 are sent to the linear prediction circuit 7, and the corrected value of the power prediction data for the antenna 1 is obtained as shown by the solid line in FIG. . The subsequent selection of the antenna is performed using the new prediction data. In the case of this example, as shown in FIG. 2B, antenna 1 is used until time t6, and after that, antenna 2 is used.

The above is the case where the antenna 1 is used at the time t5, but the same applies when the antenna 2 is used. In this case, the prediction data stored in the memory 9 is corrected. Further, in the example of FIG. 2, the prediction data is not corrected until t5, which is the switching point of the antenna in the first prediction, but this may be performed periodically at shorter intervals. That is, at that time, the reception power is measured for the antenna being used, and the prediction data in the corresponding memory is updated. In the usual case, it is considered that the correct selection can be made by making corrections at intervals as short as possible.

[0010]

As described above in detail, according to the present invention, it can be expected that a correct antenna is selected with a high probability in a burst, and there is no need to increase the number of receiving circuits, so that the hardware scale is reduced. It is possible to provide an antenna selection diversity receiver that can be expected to improve communication quality on the order of a branch selection diversity receiver without a large increase in the number of antennas.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an antenna selection diversity receiver according to the present invention.

FIG. 2 is a diagram for explaining the operation of the antenna selection diversity receiver of the present invention.

[Explanation of symbols]

 1, 2 antenna 3 antenna switching circuit 4 reception circuit 5 power measurement circuit 6 control circuit 7 straight line prediction circuit 8, 9 memory

Claims (1)

(57) [Claims] A first antenna and a second antenna;
One with strong reception power among two antennas
Antenna for receiving operation by connecting the antenna of
In a diversity receiver, just before receiving a burstSaidTwo antennas each
Measures received power twice usingPower measurement circuit From the measured power value, the two antennas within the burst period
Na each Linear prediction of received powerA linear prediction circuit A memory for storing the linearly predicted received power; The linearly predicted received power of the stored two antennas
Compare the forecast data of The first ante
Is expected to have higher received powerperiodThen the first
Using the antenna ofThe second antenna has higher received power
In the period when it is predicted thatI'll use the second antenna
USelect and selectThe received power of the antennaMeasured electricity
Using force valuesPredicting the subsequent received power of the antennaDe
Data, And the updated forecastReceive based on data
Control circuit to select the antenna whose power is predicted to be strong
With the roadAntenna selection diversity
H receiver.