JPH0993227A - Diversity receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the gain stably high by reducing the scale of the hardware of an antenna by conducting diversity reception based on the selective synthesis method as to plural branches from which different directivity is obtained via a common element. SOLUTION: The directivity of an inverted F antenna 75 to four feeding ends individually depends on the distribution of current of each element corresponding to each feeding end and differs from each other. A common contact of an antenna switch 73 is connected with other contact for a time slot period and a common contact of an antenna switch 41 is connected with each contact corresponding to a 1st to 4th feeding ends of the inverted F antenna 75 sequentially at a prescribed period. A reception section 77 receives a reception wave via the switch 73 and a filter 76, informs it to a microprocessor 79, the microprocessor 79 stores the informed electric field strength and connects the common contact to a maximum value. Thus, the possibility of deteriorated quality is considerably suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for performing diversity reception based on a selective combining method in a wireless transmission system to which a TDMA system is applied.

[0002]

2. Description of the Related Art A mobile communication system was developed to provide a telephone-based communication service to moving bodies such as ships, airplanes and trains. In recent years, highly developed digital wireless transmission technology has been applied. The number of subscribers using portable mobile station devices is rapidly increasing because services are provided in cooperation with digital communication networks and the market has been liberalized.

However, in such a mobile communication system, the transmission characteristics of the radio transmission line formed between the mobile station and the base station are set on the transmission line according to the movement of the mobile station. The features and terrain in which it is located change from moment to moment and fluctuate constantly, and the received waves are significantly fading. FIG. 8 is a diagram illustrating a configuration example of a mobile type mobile station device.

In the figure, the feeding end of the monopole antenna 71 is connected to one contact of an antenna switch 73 and the output of a bandpass filter 74 via a matching circuit 72, and the other contact of the antenna switch 73 is an inverted F type. The antenna 75 is connected to the feeding end. The common contact of the antenna switch 73 is connected to the input of the microprocessor 79 via the bandpass filter 76, the receiving unit 77 and the A / D converter (A / D) 78, and the first output thereof controls the antenna switch 73. Connected to input. The second output of the microprocessor 79 is connected to the input of the transmitter 80, and its output is connected to the input of the bandpass filter 74.

In the mobile station device having such a configuration, the inverted F type antenna 75 is mounted along the back surface of the housing, and the monopole antenna 71 is retractably housed in the upper portion of the housing. Therefore, the directivity in the vertical direction between the monopole antenna 71 and the inverted F-type antenna 75 is different as shown by the thin line and the dotted line in FIG. 9, respectively. On the other hand, the receiving unit 7
7 is a monopole antenna 71 or an inverted F-type antenna 7
5 and demodulates the received wave given through the antenna switch 73 and the bandpass filter 76 based on a predetermined frame structure, and the timing of each frame based on such a frame structure and its demodulation. The electric field strength measured in the process of
8 to the microprocessor 79.

The microprocessor 79 detects the preceding preceding time slot closest to the time slot to be received by the own station among the time slots in which the received wave is unlikely to arrive at the own station on the basis of the timing. By alternately selecting the feeding ends of the monopole antenna 71 and the inverted F-type antenna 75 via the antenna switch 73 during the time slot, the electric field strength of the reception wave individually obtained via these antennas can be obtained. get.

Further, the microprocessor 79 compares the electric field intensities thus obtained with each other, and during the subsequent time slot, the monopole antenna 71 and the inverted F-type antenna 75 have power feeding ends. , The one corresponding to the one having the larger value of the electric field strength is selected through the antenna switch 73. Therefore, the electric field strength of the received wave received for such a time slot is the electric field strength of the received wave arriving in parallel to the monopole antenna 71 and the inverted F-type antenna 75, as shown by the thick line in FIG. The one with a high value is constantly selected and given to the receiving unit 77,
Diversity reception based on the selective combining method is performed.

Regarding the directivity of the aerial system of the mobile station apparatus, the maximum value is selected for each direction, as indicated by the thick line in FIG. The transmission operation performed by the microprocessor 79 through the transmission unit 80, the bandpass filter 74, the matching circuit 72, and the monopole antenna 71 based on the procedure of the wireless channel setting control is not directly related to the present invention. The description is omitted here.

Further, the monopole antenna 71 and the inverted F type antenna 75 are used as an antenna for both transmission and reception and an antenna for reception only, respectively, through an antenna switch 73 whose contacts are switched by a microprocessor 79. The detailed operation of each part involved in the switching is not related to the present invention, and therefore its description is omitted here.

[0010]

However, in such a conventional example, the directivity is averaged in each direction as shown in FIG. 9, but the gain is low in the directions shown in FIG. Therefore, when operating in an area where multipaths frequently occur, such as in a high-rise building street, there is a high possibility that transmission quality will deteriorate.

As a method for avoiding such a deterioration in transmission quality, for example, there is a method for adding a branch which is a target of selective combining, but such a method is particularly applicable to a portable mobile station apparatus. In many cases, it cannot be applied in practice because miniaturization and weight reduction are hindered and power consumption increases. An object of the present invention is to provide a diversity receiver that can stably maintain a high gain while suppressing an increase in hardware scale.

[0012]

FIG. 1 is a block diagram showing the principle of the invention described in claims 1 and 3. The invention according to claim 1 has an antenna 11 having a plurality of feeding ends and receiving a received wave forming a TDMA frame, and fetching the received waves arriving at the antenna 11 through the plurality of feeding ends. , The electric field strength measuring means 13 for sequentially measuring the electric field strength in a period preceding the time slot to be received by the own station based on the frame structure, and the electric field strength measuring means 13 among the plurality of feeding ends. It is characterized by further comprising: demodulation means 15 for taking in the received wave of the time slot via the one having the maximum value of the electric field strength and demodulating the received wave.

FIG. 2 is a block diagram showing the principle of the second aspect of the present invention. The invention according to claim 2 has a plurality of matching means for individually matching impedances with respect to the antenna 11 having a plurality of feeding ends and receiving a received wave forming a TDMA system frame. 21 ₁ ~
21 _N and the received waves arriving at the antenna 11 are individually fetched from a plurality of feeding ends through a plurality of matching means 21 _{1 to} 21 _N , and a period preceding a time slot to be received by the own station based on the frame configuration. Electric field strength measuring means 23 for sequentially measuring the electric field strength of a plurality of electric field strengths and a plurality of matching means 21 ₁ to Of the 21 _N , the demodulating means 25 for taking in the received wave of the time slot through the matching means corresponding to the power feeding end and demodulating the received wave
And characterized in that:

According to a third aspect of the present invention, in the diversity receiver according to the first aspect, the electric field strength measuring means 1 is used.
3 has a means for successively matching impedances of the plurality of power feeding ends at which a received wave whose electric field strength is to be measured is obtained, and the demodulation means 15 has a plurality of power feeding ends. , And has means for successively matching impedances at a feeding end from which a received wave to be demodulated is obtained.

[0015]

In the diversity receiver according to the first aspect of the present invention, the antenna 11 has a current distribution on the element depending on which of the plurality of feeding ends is to be fed. Different and different directivity. The electric field strength measuring means 13 identifies the period preceding the time slot to be received by the local station, based on the structure of the TDMA system frame given by the received wave arriving at the antenna 11, and described above over that period. The electric field strengths of the received waves individually obtained at the plurality of feeding ends are sequentially measured in series. The demodulation means 15 takes in the received wave of the above-mentioned time slot and demodulates it through the feeding end from which the maximum value of the electric field strength thus measured is obtained.

That is, since diversity reception based on the selective combining method is performed on a plurality of virtual branches having different directivities via a common element, the scale of hardware constituting the antenna system can be suppressed to a small size, and The gain is kept stable and high. In the diversity receiver according to the invention of claim 2, the antenna 11 has a different current distribution on the element depending on which of the plurality of feeding ends is to be fed,
The directivity is also different. The matching means 21 _{1 to} 21 _N individually match the impedances of these feeding ends. The electric field strength measuring means 23 identifies the period preceding the time slot to be received by the local station based on the structure of the TDMA system frame given by the received wave arriving at the antenna 11, and described above over that period. The electric field strengths of the received waves obtained from the plurality of feeding ends via the matching units 21 _{1 to} 21 _N are sequentially measured in series. Demodulation means 15
Is received through the feeding end from which the maximum value of the electric field strength measured in this way is obtained and the matching means corresponding to the feeding end among the matching means 21 _{1 to} 21 _N. Capture and demodulate waves.

That is, since diversity reception based on the selective combining method is performed while surely matching impedances individually for a plurality of virtual branches having different directivities via a common element, an antenna system is constructed. The size of the hardware used is kept small, the gain is stably maintained high, and the constraint relating to the formation of a plurality of feeding ends on the device is relaxed.

In the diversity receiver according to the third aspect of the present invention, the electric field strength measuring means 13 successively matches impedances of the plurality of feeding ends at which the receiving wave whose electric field strength is to be measured is obtained. In addition, the demodulation means 15 sequentially matches the impedances of the plurality of power supply ends with respect to the power supply end from which the received wave to be demodulated is obtained.

That is, since impedance matching can be surely achieved at these power feeding ends without providing a plurality of matching means individually corresponding to the plurality of power feeding ends, the scale of the hardware constituting the antenna system is reduced. In addition, similarly to the diversity receiver according to the second aspect, a high gain is stably maintained, and restrictions on formation of these feeding ends are relaxed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A portable telephone according to the present invention will be described in detail below with reference to the drawings. FIG. 3 is a diagram showing an embodiment corresponding to the invention described in claim 1. In the figure, parts having the same functions and configurations as those shown in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted here.

The difference between the present embodiment and the conventional example shown in FIG. 8 is that the inverted F-type antenna 75 is provided with four feeding ends, and these feeding ends are the first to fourth portions of the antenna switch 41. The antenna switch is connected to the contact, and the common contact of the antenna switch is connected to the other contact of the antenna switch 73 and the microprocessor 79 is connected to the control terminal.
It is at the point where the third output of is connected.

Regarding the correspondence relationship between the present embodiment and the block diagram shown in FIG. 1, the inverted F type antenna 75 corresponds to the antenna 11, and the antenna switches 41 and 73, the band pass filter 76, the receiving section 77 and A. The / D converter 78 and the microprocessor 79 correspond to the electric field strength measuring means 13, and the antenna switches 41 and 73, the bandpass filter 76 and the receiving section 77 correspond to the demodulating means 15.

FIG. 4 is a diagram for explaining the operation of this embodiment. Hereinafter, the operation of the present embodiment will be described with reference to FIGS. The directivity that the inverted F-type antenna 75 individually has with respect to the above-mentioned four feeding ends is determined by the distribution of the current in each part of the element corresponding to these feeding ends, and differs, for example, as shown in FIGS. .

On the other hand, the microprocessor 79 obtains a time slot preceding the time slot to be received by the local station in the same manner as in the conventional example, and makes the common contact of the antenna switch 73 the other contact during the time slot. Connect and connect the common contact of the antenna switch 41 to the reverse F
The contacts corresponding to the first feeding end to the fourth feeding end of the die antenna 75 are sequentially switched and connected at a constant cycle (FIGS. 4 to).

The receiving section 77 takes in the received waves obtained from the first feeding end to the fourth feeding end of the inverted F type antenna 75 in this way through the antenna switch 73 and the band pass filter 76, and sequentially. The electric field strength is measured and notified to the microprocessor 79. When the microprocessor 79 accumulates the electric field strength notified in this way, and when the electric field strength of the received wave obtained from the above-mentioned fourth feeding end is notified, those of the contacts of the antenna switch 41 The common contact is connected to the one with the maximum electric field strength of (Fig. 4).

That is, the received wave given to the receiving unit 77 for each time slot to be received by the local station has the maximum sensitivity among the feeding ends formed in the inverted F-type antenna 75 without adding any antenna. It is given through a certain feeding end. Therefore, the increase in the scale of the hardware is suppressed, the effective bias depending on the direction of directivity is suppressed as shown by the thick line in FIG. 5, and the wireless line is forcibly forced based on the procedure of the wireless channel setting control. The possibility of disconnection and deterioration of transmission quality is greatly reduced compared to the conventional example.

In the above-described embodiment, four feeding ends are formed in the inverted F-type antenna 75, which is composed of a plate-shaped element as in the conventional example, but the present invention has an inverted F-type antenna having such a configuration. Not limited to the antenna, for example, as shown by hatching in FIG. 6, it is possible to reduce the size by filling a dielectric between the element and a grounding plate formed so as to face the element. it can.

FIG. 7 is a diagram showing an embodiment corresponding to the invention described in claims 2 and 3. In the figure, parts having the same functions and configurations as those shown in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted here. The difference between the present embodiment and the configuration of the conventional example shown in FIG. 8 is that the first and fourth feeding ends are formed in the monopole antenna 71.
Through these feeding end matching circuit 61 ₁ to 61 ₄ provided in place of the matching circuit 72, respectively the antenna switch 6
2 is connected to the first to fourth contacts of the antenna switch, the common contact of the antenna switch is connected to one contact of the antenna switch 73 and the output of the bandpass filter 74, and the control terminal of the microprocessor 79. It is at the point connected to the third output.

The difference between the present embodiment and the block diagrams shown in FIGS. 1 and 2 lies in the monopole antenna 7
1 corresponds to the antenna 11, the variable matching circuit 63 to the matching circuit 61 ₁ to 61 ₄ and described below correspond to the matching means 21 ₁ through 21 _N, the antenna switch 62,73, bandpass filter 76, reception section 77, A The / D converter 78 and the microprocessor 79 correspond to the electric field strength measuring means 13 and 23, and the antenna switch 62, the variable matching circuit 63, the antenna switch 73, the band pass filter 76 and the receiving unit 77 correspond to the demodulating means 15 and 25. To do.

The operation of this embodiment corresponding to the invention described in claim 2 will be described below. The directivity that the monopole antenna 71 individually has with respect to the above-mentioned four feeding ends is
It is determined by the current distribution in each part of the element corresponding to these power feeding ends, and varies depending on the position of each power feeding end.
The matching circuit 61 ₁ to 61 _4, the impedance of different monopole antenna 71 by the difference of these feeding end, taking individually matched.

On the other hand, the microprocessor 79 obtains a time slot preceding the time slot to be received by the local station in the same manner as in the conventional example, and the common contact of the antenna switch 73 is set to one of the contacts during the time slot. In addition to the connection, the common contact of the antenna switch 41 is connected to the contact corresponding to the first feeding end or the fourth feeding end of the monopole antenna 71 by sequentially switching at a fixed cycle (FIGS. 4 to).

The receiving unit 77, the matching circuit 61 ₁ to 61 _4, the antenna switch 62,73 and band-pass filter 7
In this way, the received waves obtained at the first feeding end or the fourth feeding end of the monopole antenna 71 in this way are taken in, and the electric field strength is sequentially measured and the microprocessor 7
Notify 9. When the microprocessor 79 accumulates the electric field strength notified in this way and is notified of the electric field strength of the received wave obtained from the fourth feeding end described above,
Among the contacts of the antenna switch 41, the one having the maximum electric field strength is connected to the common contact (see FIG. 4).
).

That is, the received wave given to the receiving section 77 for the time slot to be received by the own station has the maximum sensitivity among the plurality of feeding ends formed in the monopole antenna 71 without any additional antenna. Is provided through the power supply end. Therefore, the increase in the scale of hardware is suppressed, the effective bias depending on the direction of directivity is suppressed, and the wireless line is forcibly disconnected or the transmission quality is deteriorated based on the procedure of the wireless channel setting control. The possibility is greatly reduced compared to the conventional example.

An embodiment corresponding to the invention of claim 3 will be described below. Differences of the configuration of the embodiment of the invention according to claim 2 described above with the present embodiment, as shown by a dotted line in FIG. 7, the variable matching circuit 63 is an antenna in place of the matching circuit 61 ₁ to 61 ₄ It is arranged between the common contact of the switch 62 and one contact of the antenna switch 73 and the output of the bandpass filter 74, and the fourth input of the microprocessor 79 is connected to the control input of the variable matching circuit 63. , Monopole antenna 71
Each of the feeding ends of is connected directly to each contact of the antenna switch 62.

In the variable matching circuit 63, the first to fourth feeding ends formed in the monopole antenna 71 are
The impedance matching mode to be individually set is preset. Similarly to the embodiment corresponding to the invention described in claim 2, the microprocessor 79 switches and connects a common contact to any contact of the antenna switch 62, and sequentially notifies the variable matching circuit 63 of the contact.

The variable matching circuit 63 performs impedance matching in a manner adapted to the contact notified as described above among the preset manners as described above. Therefore, according to this embodiment, downsizing of hardware is worn by mounting a single variable matching circuit 63 in place of the matching circuit 61 ₁ to 61 _4, and similarly to the embodiments described above Therefore, the transmission quality can be surely improved without adding an antenna.

In each of the above-mentioned embodiments, claim 1
The invention according to claim 3 is applied to a mobile type mobile station apparatus, but these inventions are not limited to such a mobile station apparatus, and are installed in, for example, a radio base station of a mobile communication system. Similarly, the present invention can be applied to a receiving device for wireless communication and a receiving device for other wireless transmission system. Further, in each of the above-described embodiments, the inverted F type antenna 75 and the monopole antenna 71 are used.
However, the present invention is not limited to such an antenna, and the shape, structure, dimensions, radiating element, etc. may be changed as long as a desired number of feeding ends can be reliably formed. Any antenna is applicable.

Further, in each of the above-described embodiments, the structure of the frame forming the received wave is not shown in detail, but the present invention is not limited to the local station under the mode of fluctuation of the transmission characteristic in the wireless transmission line. , The desired correlation is secured in the transmission characteristics between the time slot to be received by the slot and the slot preceding it, and the electric field strengths of all the received waves obtained from the above-mentioned multiple feeding ends are reliably measured. If so, any frame structure can be applied.

Further, in each of the above-mentioned embodiments, the monopole antenna 71 and the inverted F-type antenna 75 are provided with four feeding ends, but the present invention is not limited to such a number of feeding ends, and Any number of feed ends may be formed, provided that the field strength is reliably measured in the preceding time slot. Further, in each of the above-described embodiments, no operation of diversity reception is performed based on the selective combining method via the antenna switch 73, but the operation is performed in parallel in the same manner as the conventional example. Alternatively, in such a case, the antenna switches 41 and 62 and the antenna switch 73 may be combined and configured.

Further, in each of the embodiments corresponding to the inventions described in claims 2 and 3, the power feeding for obtaining the received wave whose electric field strength is to be measured and the received wave of the time slot to be received by the own station. Although impedance matching is achieved at all the ends, the present invention is not limited to such a configuration. For example, the error in the measured value of the electric field strength due to the difference in impedance at each feeding end is within an allowable range. If it is within the range or can be corrected as a known value, the matching may be omitted for the period in which the electric field strength is measured.

[0041]

As described above, the first to third aspects are provided.
In the invention described in (1), diversity reception based on the selective combining method is performed for a plurality of branches in which different directivities are obtained through a common element, and the gain of the antenna constituting the antenna system can be suppressed small. Stable and maintained high.

Further, in the inventions described in claims 2 and 3, the impedances are surely matched with respect to the plurality of feeding ends individually forming the plurality of branches, so that the gain is lowered. It is suppressed, and the restrictions relating to the formation of these feeding ends are greatly relaxed.

Further, in the invention according to the third aspect, since the impedance matching described above is provided through the common matching means, the scale of the hardware constituting the antenna system can be further reduced. Therefore, in the wireless transmission system to which these inventions are applied, the transmission quality is improved by reducing the cost, downsizing and power saving of the device, and the service quality and reliability are enhanced.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the invention described in claims 1 and 3.

FIG. 2 is a principle block diagram of the invention according to claim 2;

FIG. 3 is a diagram showing an embodiment corresponding to the invention described in claim 1;

FIG. 4 is a diagram illustrating the operation of the present embodiment.

FIG. 5 is a diagram showing directional characteristics during reception according to the present embodiment.

FIG. 6 is a diagram showing another configuration of the inverted F-type antenna.

FIG. 7 is a diagram showing an embodiment corresponding to the invention described in claims 2 and 3.

FIG. 8 is a diagram showing a configuration example of a mobile type mobile station device.

FIG. 9 is a diagram showing directivity of both antennas.

FIG. 10 is a diagram showing the electric field strength of a received wave received under the selective combining method.

[Explanation of symbols]

 11 antenna 13,23 electric field strength measuring means 15,25 demodulating means 21 matching means 41,62,73 antenna switch 61,72 matching circuit 63 variable matching circuit 71 monopole antenna 74,76 bandpass filter 75 inverted F type antenna 77 reception Part 78 A / D converter (A / D) 79 Microprocessor 80 Transmitter

Claims (3)

[Claims] 1. An antenna having a plurality of feeding ends and to which a received wave forming a TDMA frame frame arrives, and a received wave coming to the antenna is taken in through the plurality of feeding ends to obtain a frame of the frame. Based on the configuration, the electric field strength measuring means for sequentially measuring the electric field strength in a period preceding the time slot to be received by the local station, and the electric field strength measured by the electric field strength measuring means among the plurality of feeding ends. And a demodulation means for demodulating the received wave of the time slot by taking in the received wave of the time slot through which the maximum value is obtained. 2. An antenna having a plurality of feeding ends and receiving a received wave forming a TDMA frame, a plurality of matching means for individually matching impedances of the plurality of feeding ends, and the antenna. The received waves arriving at are individually fetched from the plurality of feeding ends through the plurality of matching means, and the electric field strength of the period preceding the time slot to be received by the own station is sequentially measured in series based on the frame configuration. And a matching field corresponding to the feeding end of the plurality of matching means from the one that obtains the maximum value of the electric field strength measured by the field strength measuring means among the plurality of feeding ends. And a demodulating means for demodulating the received wave of the time slot taken in via the means. 3. The diversity receiving device according to claim 1, wherein the electric field strength measuring means successively matches impedances at a feeding end of a plurality of feeding ends from which a received wave whose electric field strength is to be measured is obtained. The diversity receiving device is characterized in that the demodulating means has a means for sequentially matching impedances of the plurality of feeding ends at which a receiving wave to be demodulated is obtained. .