JPH10290189A - Diversity system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the miniaturization and lightening of a device by enabling diversity reception in one system of reception part in spite of the provision of plural antennas by separating the received field signals and received phase data of respective antennas and outputting demodulated data by performing diversity reception while using the separated respective received field signals and received phase data. SOLUTION: Antennas (a) and (b) are spatially isolated and signals receiving mutually independent phasing are captured. A delay line 3 delays the received signal from the antenna (b) for 1/2 symbol time and outputs it to an antenna switcher 4 and based on an antenna switching signal 14, the antenna switcher 4 alternately outputs the signal from the antenna (a) and the signal from the antenna (b) through the delay line 3 to a reception part 5. By delaying the received signal from the antenna (b) for 1/2 symbol time and changing over the antenna switcher 4 so as to receive respective symbol points at one reception part 5, two antennas are received by one reception part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity system in digital wireless communication.

[0002]

2. Description of the Related Art Various methods have been considered for a diversity system in digital radio communication. However, if it is desired to receive received signals from a plurality of antennas for each symbol by combining diversity or selective diversity, the number of received signals is equal to the number of antennas. Machine is required (see FIG. 1).

As a method for realizing diversity reception with only one system of receivers for a plurality of antennas, there is a switch selection diversity reception system as shown in FIG. This method is a method of demodulating only a received signal from any one of a plurality of branches using an antenna switch, and forcibly switching a selected branch when the received signal level falls below a threshold. is there.

In this switch selection diversity reception method, since the reception state of a branch other than the selected branch is not known, the reception state may be worse than that of the branch before switching. In addition, since the phases of the signals between the branches when the antenna is switched are generally different, in the case of a digitally modulated received signal, discontinuity in the phase due to the switching causes a symbol error.

Further, in the antenna switching diversity system disclosed in Japanese Patent Application Laid-Open No. Hei 6-132940, the branch to which the switch selection diversity receiving system is switched may be worse than the reception state of the branch before switching. Compensates for the two major drawbacks mentioned above, in which a symbol error occurs due to phase discontinuity due to phase discontinuity. However, two RF circuits are required, and when performing diversity reception for each symbol, the reception electric field level for each branch is newly increased. There are problems such as the necessity of a detection circuit and the inability to perform combined diversity reception.

[0006]

In these conventional diversity systems, if combining diversity or selection diversity is to be performed for each symbol, a plurality of receivers are required, or an electric field detection circuit and a plurality of RFs for each branch are required.
There is a problem that an auxiliary circuit such as a circuit is required and the scale of the device is increased.

[0007] The diversity system in digital wireless communication of the present invention has been made in view of the above-mentioned problems, and has the following objects. Small and lightweight. Low power consumption.

[0008]

In order to achieve the above object, a. delay means for mutually shifting signals received by n antennas by 1 / n symbol time, a sample timing generator for generating a sample timing signal from demodulated data, and generating an antenna switching signal based on the sample timing signal An antenna control unit, a switching unit for switching an output signal of the delay unit by an antenna switching signal and combining the signals into one signal, detecting an electric field level of the output signal of the switching unit, outputting the signal as a received electric field signal, and And a receiving unit that detects and outputs the received electric field signal and the received phase data of each antenna from the received electric field signal and the received phase data by using the sample timing signal. And a receiver for performing diversity reception using the received phase data and outputting the demodulated data. Means for and a Bashichi portion is employed. b. The diversity unit includes a comparing unit that compares the magnitude of the received electric field signal, and outputs the received phase data from the antenna having the largest received electric field signal as demodulated data. c. Further, the diversity section may employ a means of vector-combining the received electric field signal and the received phase data of each antenna, and outputting the phase of the combined signal as demodulated data. d. On the other hand, for the sample timing generator,
A clock synchronized with the symbol rate is generated based on the demodulated data, a clock having an n-fold frequency is generated from the clock, and a position where the rising or falling point of the clock is a symbol point of a reception signal of each antenna. Means of generating an adjusted sample timing signal is employed. e. The antenna control unit employs a unit that delays the sample timing signal for a fixed time and generates an antenna switching signal such that the switching unit switches sufficiently before the symbol point of the received signal of each antenna.

[0009]

According to the above-mentioned means, since the signals received from the antennas are combined into one signal and then input to the receiver, a plurality of receivers are not required for diversity reception.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a diversity system in digital wireless communication according to the present invention will be described with reference to the drawings. [1] Description of Configuration First, the functional configuration of the present embodiment will be described with reference to FIG. This embodiment relates to a case where diversity reception is performed using two antennas.

In this figure, antenna a and antenna b
Captures signals that are spatially separated from each other and have undergone independent fading. The delay line 3 delays the received signal from the antenna b by シ ン ボ ル symbol time and outputs the delayed signal to the antenna switch 4. The antenna switching unit 4 alternately outputs a signal from the antenna a and a signal from the antenna b via the delay line 3 to the receiving unit 5 based on the antenna switching signal 14.

FIG. 4 shows an example of a circuit configuration of the antenna switch 4. In addition, as an example of the configuration of the antenna switch 4, there is a circuit shown in FIG. 6-116 on page 290 of "Revised High-frequency Circuit Design Know-how" (CQ Publishing Co., Ltd.).

The receiving section 5 converts the frequency of the signal input from the antenna switch 4 into an IF frequency, limits the band to obtain a desired frequency component, and generates a sample timing signal 13 generated by the sample timing generating section 7. Is used to detect the phase, and the detected signal is used as reception phase data 1
2 is output to the diversity unit 6 and the electric field intensity of the target frequency component is detected to receive the electric field signal 11
Is output to the diversity unit 6.

For example, the sample timing generator 7
A clock synchronized with the symbol rate is generated based on the demodulated data described below, a clock having an n-fold frequency is generated from the clock, and the rising point or the falling point of the clock is the same as the symbol point of the reception signal of each antenna. A sample timing signal whose position is adjusted so as to be generated is generated.

Diversity section 6 has a circuit configuration as shown in FIG. 5 and includes reception phase data 12 and reception electric field signal 11.
Is separated into signals of the respective systems based on the sample timing signal 13, and based on the signal obtained by the separation, synthesis diversity or selection diversity reception is performed and output as demodulated data 15.

Further, the antenna control unit 8 inputs the signal from the antenna 1 and the signal from the antenna 2 which is delayed by 1/2 symbol time through the delay line 3 to the receiving unit 5 at each symbol point. As described above, the antenna switching signal 14 is generated from the sample timing signal 13 and output to the antenna switching device 4. For example, the antenna control unit 8 delays the sample timing signal 13 for a certain period of time, and generates the antenna switching signal 14 so that the antenna switching unit 4 switches sufficiently before the symbol points of the reception signals of the antennas a and b.

[2] Description of Operation Next, the operation of the diversity system having the above configuration will be described with reference to the timing chart shown in FIG. In this figure,
A is the transmission data from the other party, B is the received signal at antenna a, C is the received signal at antenna b, D is the input signal to antenna switch 4, ie, the received signal B,
E is an input signal to the antenna switch 4, that is, an output signal of the delay line 3, F is an antenna switching signal 14 (law: a system (the input signal D), high: b system (the input signal E), G is an antenna The output signal of the switch 4, H is the sample timing signal 13, I is the received phase data 12, J is the received electric field signal 11, K is the a-system received phase data 12, L is the b-system received phase data 12, and M is N is the reception electric field signal of the a system, and N is the reception electric field signal of the b system.

First, the transmission data A is subjected to distortion such as fading in the transmission path, so that the antenna a and the antenna b
Is received. The transmission data A transmitted in this manner is
The signals are received by antennas a and b, respectively, and output as received signals B and C, respectively. Among them, the received signal B is sent to the antenna switch 4 as an input signal D, and the received signal C is input to the antenna switch 4 as an input signal E after being delayed by 遅 延 symbol time by the delay line 3.

The antenna switching unit 4 outputs the antenna switching signal 1
When 4 (F) is “low”, the a-system input signal D is selected, and when “high”, the b-system input signal E is selected and output to the receiver 5 as the output signal G. The output signal G input to the receiving unit 5 is frequency-converted to an IF frequency and band-limited to obtain a target frequency component, and then the sample timing signal 13 (H) generated by the sample timing generating unit 7. And is output to the diversity unit 6 as reception phase data 12 (I). Further, the receiving unit 7 detects a target frequency component and outputs it to the diversity unit 6 as a received electric field signal 11 (J).

On the other hand, in the sample timing generator 7,
The rising position and falling position of the sample timing signal 13 (H) are adjusted so that the reception phase data 12 (I) is sampled at the symbol point, and output to the receiving unit 5.

The diversity unit 6 uses the sample timing signal 13 to receive the received phase data 12 and the received electric field signal 1.
1 with the reception phase data K, L and the reception electric field signals M, N
Separate first. Then, selective diversity reception is performed by comparing the magnitudes of the received electric field signals M and N using a comparing means and outputting received phase data of the larger received electric field signal from the antenna as demodulated data. When performing diversity reception, the diversity unit 6 performs vector synthesis of the received electric field signals M and N of the antennas a and b and the received phase data K and L, and uses the phase of the synthesized signal as demodulated data. Output. Note that the antenna control unit 8
Then, the antenna switching signal 14 is generated from the sample timing signal 13 and output to the antenna switching device 4.

As described above, of the received signals obtained from antennas a and b, the received signal from antenna b is delayed by シ ン ボ ル symbol time so that one receiving point 5 can receive each symbol point. Antenna switch 4
, The reception signals from the two antennas a and b can be received by one receiver 5 to perform the combining diversity or the selection diversity.

In the above embodiment, a case has been described where diversity reception is performed using two antennas. However, the present invention is not limited to this, and diversity reception is performed using three or more n antennas. It is also conceivable to perform reception. In this case, the received signals obtained from each of the n antennas are input to the antenna switch with a delay of 1 / n symbol time from each other using the delay means such as the delay line.

[0024]

As described above, according to the present invention,
delay means for mutually shifting signals received by n antennas by 1 / n symbol time, a sample timing generator for generating a sample timing signal from demodulated data, and the antenna switching signal based on the sample timing signal An antenna control unit to generate a signal, and an output signal of the delay unit are switched by an antenna switching signal to 1
A switching unit that combines the two signals into one signal, a receiving unit that detects an electric field level of an output signal of the switching unit and outputs the signal as a received electric field signal, detects a phase and outputs the received signal as received phase data, and a sample timing signal. The received electric field signal and received phase data of each antenna are separated from the received electric field signal and received phase data, and diversity reception is performed using the separated received electric field signals and received phase data to output the demodulated data. Since a diversity unit is provided, it is possible to perform diversity reception with one system of receiving unit despite the presence of a plurality of antennas. Therefore, the device can be reduced in size, weight, and power consumption.

[Brief description of the drawings]

FIG. 1 is a first block diagram illustrating an example of a conventional diversity system.

FIG. 2 is a second block diagram illustrating an example of a conventional diversity system. FIG. 2 is a timing chart for explaining the embodiment of FIG. 1.

FIG. 3 is a block diagram showing a functional configuration of an embodiment of a diversity system according to the present invention.

FIG. 4 is a circuit diagram showing a detailed configuration example of the antenna switch shown in FIG. 3;

FIG. 5 is a circuit diagram showing a detailed configuration example of a diversity unit shown in FIG. 3;

FIG. 6 is a diagram showing a timing relationship between signals of respective units in the diversity system shown in FIG. 3;

[Explanation of symbols]

 3 Delay line 4 Antenna switch 5 Receiver 6 Diversity 7 Sample timing generator 8 Antenna controller 11 Received electric field signal 12 Received phase data 13 Sample Timing signal 14 Antenna switching signal 61 Inverter 62 Capacitor 63 Coil 64 PIN diode 65 PIN diode 66 Coil 67 Resistor 68 Capacitor 69 Coil 70 Capacitor

Claims (5)

[Claims] A delay means for shifting signals received by n antennas by 1 / n symbol time from each other;
A sample timing generator (7) for generating a sample timing signal from the demodulated data; an antenna controller (8) for generating an antenna switching signal based on the sample timing signal; Switching means (4) for switching by a signal to combine the signals into one signal; and a reception means for detecting the electric field level of the output signal of the switching means and outputting the electric field signal as a reception electric field signal, and detecting the phase and outputting it as reception phase data. And (5) separating the received electric field signal and received phase data of each antenna from the received electric field signal and received phase data using the sample timing signal, and using the separated received electric field signal and received phase data. A diversity unit (6) for performing diversity reception and outputting the demodulated data. Diversity scheme that. 2. The diversity system according to claim 1, wherein the diversity unit includes comparison means for comparing the magnitude of the received electric field signal, and outputs received phase data from an antenna having the largest received electric field signal as demodulated data. A diversity system characterized by the following. 3. The diversity system according to claim 1, wherein the diversity unit vector-combines the received electric field signal and the received phase data of each antenna, and outputs the phase of the combined signal as demodulated data. method. 4. The diversity system according to claim 1, wherein the sample timing generation unit comprises:
A clock synchronized with the symbol rate is generated based on the demodulated data, a clock having an n-fold frequency is generated from the clock, and a position where the rising or falling point of the clock is the symbol point of the reception signal of each antenna. A diversity system for generating an adjusted sample timing signal. 5. The diversity system according to claim 1, wherein the antenna control unit delays the sample timing signal for a predetermined time so that the switching unit switches sufficiently before the symbol point of the reception signal of each antenna. A diversity system characterized by generating an antenna switching signal.