JP3276360B2 - Wireless communication system and transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system such as a mobile phone and a mobile phone, and more particularly, to a radio communication system in an environment where a plurality of transmitters transmit the same signal at the same frequency. The present invention relates to a wireless communication system, a transmitter and a receiver capable of covering a wide area with a simple configuration.

[0002]

2. Description of the Related Art For example, an automobile telephone system comprises a base station connected to a communication network and a mobile station corresponding to a mobile phone or the like. In such a system, the communicable distance between the base station and the mobile station is closely related to the transmittable power. Therefore, in order to cover a wide area, a method of transmitting the same signal at the same frequency from a plurality of base stations can be considered.

Hereinafter, a conventional wireless communication system will be specifically described with reference to the drawings. For example, FIG. 11 is a diagram showing a configuration of a conventional wireless communication system having a configuration for covering a wide area. In FIG. 11, 1
07A and 107B are base stations, 101 is a transmission information input terminal to which transmission information is input from the network,
102A and 102B are modulators, and 103A and 103
B is an antenna of the base station, 104 is a mobile station,
105 is an antenna of the mobile station. Here, the internal configuration of base stations 107A and 107B is described focusing on modulators 102A and 102B, which are basic functions. Further, base station 107A transmits information to be transmitted from antenna 103A, and similarly, base station 107B transmits information to be transmitted from antenna 103B. Then, in the mobile station 104, the antenna 105 receives transmission signals from the two base stations 107A and 107B.

In the radio communication system configured as described above, the radio wave environment usually includes the mobile station 104 and the base station 1.
07A and 107B. FIG. 12 is a timing chart for explaining radio wave propagation in a conventional wireless communication system. For example, mobile station 104
Realizes a wide range of coverage by simultaneously receiving transmission signals from the two base stations 107A and 107B. However, as shown in FIG. 12, in a specific area (when the distance from the mobile station 104 to the two base stations is almost the same), the reception signal RA from the base station 107A and the reception signal of the base station 107B A case occurs where the power of the RB is the same, but the polarity is reversed. In such a case, the two received signals RA and RB cancel each other out, and after combining,
The phenomenon that the signal disappears occurs.

On the other hand, as an example of a conventional wireless communication system other than the above, there is a wireless communication system disclosed in Japanese Patent Publication No. 2572765. For example, in this wireless communication system, a wireless communication system with a large coverage area is realized by using a method in which a base station is provided with a plurality of antennas and a delay unit delays a transmission signal by one symbol or more. FIG. 13 is a diagram showing a configuration of a conventional radio communication system provided with a plurality of antennas at a base station, which is different from FIG. In FIG. 13, reference numeral 107 denotes a base station;
Reference numeral 101 denotes a transmission information input terminal to which transmission information is input from the network, 102 denotes a modulator, 103A denotes a first antenna of the base station 107, 106 denotes a delay unit, and 103C denotes a base station 107. Reference numeral 104 denotes a mobile station, and reference numeral 105 denotes an antenna of the mobile station 104.

In the radio communication system configured as described above, base station 107 transmits information to be transmitted from first antenna 103A, and further delays the same information by delayer 106 by one symbol or more. Thereafter, the signal is transmitted from the second antenna 103C. Further, the mobile station 104 receives transmission signals from the two antennas 103A and 103C of the base station 107 via the antenna 105. At this time, since the signals from the two antennas on the transmitting side have a time difference of one symbol or more, the time difference is
It is corrected by the equalizer inside.

In the radio communication system shown in FIG. 13, if it is assumed that the radio wave environment from the transmitting antennas 103A and 103C is independent, the received signals cancel each other out due to the diversity effect. It is possible to reduce the phenomenon of disappearance, and as a result, it is possible to improve the characteristics. However, such a configuration has a problem that a single base station is used, and a delay of one or more symbols is given to a transmission signal, so that the circuit scale of an equalizer in a mobile station increases. Was not enough.

That is, as shown in FIG. 11, in the case of realizing a wireless communication system having a wide coverage area, signals from a plurality of base stations cancel each other out at a specific place, making signal reception difficult. The 13th issue
As shown in the figure, when the base station outputs a normal transmission signal and a transmission signal delayed with respect to the normal transmission signal, there is a problem that an equalizer on the receiving side becomes complicated.

The present invention has been made in view of the above, and prevents a phenomenon in which all signals are lost after combining in a mobile station existing between a plurality of base stations, and has a simple configuration. It is an object of the present invention to provide a wireless communication system, a transmitter, and a receiver that can cover a wide area.

[0010]

DISCLOSURE OF THE INVENTION In a wireless communication system according to the present invention, a plurality of transmitters transmit the same signal at the same frequency, and a receiver receives these signals. At least one antenna is arranged for a transmitter, and an arbitrary delay (including no delay) is given to the antenna, and each transmitter is different from at least one delay output of the other transmitters. The output power is set. According to the present invention, an arbitrary delay can be given to each antenna, and further,
Since at least one delayed output between the transmitters is set to have different output power, all the signals do not disappear after combining. In addition, each transmitter independently sets the radio wave environment of the antenna to improve the characteristics by the diversity effect. Further, it is possible to set the delay setting to not more than one symbol, thereby reducing the circuit scale of an equalizer (not shown) in the receiver as compared with the conventional technique.

In the radio communication system according to the next invention, when different delays (including no delay) are given to a plurality of antennas in each transmitter as the arbitrary delay, each transmission is performed. A different combination of output powers from the corresponding delay outputs of the other transmitters is set for the transmitter. According to the present invention, a combination of transmission powers in delay outputs from a plurality of antennas of each transmitter is different between adjacent transmitters, so that a combination in a specific area which has conventionally occurred can be achieved. The phenomenon that the subsequent signal disappears is prevented beforehand. In addition, by independently setting the radio wave environment of the antenna, the characteristics are improved by the diversity effect.
Further, it is possible to set the delay setting to not more than one symbol, thereby reducing the circuit scale of the equalizer in the receiver.

[0012] In the radio communication system according to the next invention, the equalizer of the receiver demodulates a signal transmitted from at least one antenna of each transmitter. According to the present invention, the receiver demodulates, using the equalizer, delayed outputs from a plurality of antennas having different transmission powers between adjacent base stations.

In the wireless communication system according to the next invention, a plurality of transmitters transmit the same signal at the same frequency, and the receiver receives these signals. At least one antenna is arranged for each of the antennas, and a signal to be supplied to each antenna is a signal obtained by giving a different delay to the modulated signal and further performing weighting (including a complex number) synthesis. And at least one of the delay amount and the weighting factor in the transmitter is set to a different value. According to the present invention, by making at least one of the delay amount and the weighting factor in each transmitter different between adjacent transmitters, the signal after combining in a specific area, which has conventionally occurred, Disappears beforehand. Further, even when each transmitter has a single antenna, the same effect as the configuration having a plurality of antennas can be obtained. Further, it is possible to set the delay setting to not more than one symbol, thereby reducing the circuit scale of the equalizer in the receiver.

In the radio communication system according to the next invention, the equalizer of the receiver demodulates a signal transmitted from at least one antenna of each transmitter. According to the present invention, the receiver demodulates the combined signal output from the plurality of antennas using the equalizer.

[0015] In a wireless communication system according to the next invention, a transmitter having a plurality of antennas transmits the same signal, and a receiver receives these signals. The signal to be supplied is a signal obtained by giving a different delay to the modulated signal and further weighting and combining the signals, and the delay amount or at least one of the weighting factors is set to a different value between the antennas. According to the present invention, at least one of the delay amount and the weight coefficient in each signal combining unit corresponding to a plurality of antennas provided in one transmitter is made different between adjacent antennas. Thus, the phenomenon that the signal after combination disappears in a specific area, which has conventionally occurred, is prevented. Further, even when each transmitter has a single antenna, the same effect as the configuration having a plurality of antennas can be obtained. Further, it is possible to set the delay setting to not more than one symbol, thereby reducing the circuit scale of the equalizer in the receiver.

In a radio communication system according to the next invention, the equalizer of the receiver demodulates signals transmitted from the plurality of antennas.
According to the present invention, the receiver demodulates the combined signal output from the plurality of antennas using the equalizer.

In the transmitter according to the next invention, when a plurality of transmitters transmit the same signal at the same frequency, at least one antenna is arranged and an arbitrary delay (delay is given to the antenna). And a different output power from at least one delayed output of other transmitters. According to the present invention, it is possible to give an arbitrary delay to each antenna,
Furthermore, since at least one delay output between the transmitters is set to have different output powers, all signals do not disappear after combining. Also, each transmitter independently sets the radio wave environment of the antenna.

[0018] In the transmitter according to the next invention, when different delays (including no delay) are given to the plurality of antennas as the arbitrary delay, the corresponding delay in the other transmitters. It is characterized in that a different combination of output power from the delay output is set. According to the present invention, a combination of transmission powers in delay outputs from a plurality of antennas of each transmitter is different between adjacent transmitters, so that a combination in a specific area which has conventionally occurred can be achieved. The phenomenon that the subsequent signal disappears is prevented beforehand. Also, the radio wave environment of the antenna is set independently.

In the transmitter according to the next invention, when a plurality of transmitters transmit the same signal at the same frequency, at least one antenna is arranged, and a signal supplied to each antenna is A modulation signal is given a different delay to obtain a signal obtained by further weighting (including a complex number) synthesis, and at least one of a delay amount in another transmitter or a weight coefficient is set to a different value. I do. According to the present invention, by making at least one of the delay amount and the weighting factor in each transmitter different between adjacent transmitters, the signal after combining in a specific area, which has conventionally occurred, Disappears beforehand.

In the transmitter according to the next invention, when the same signal is transmitted from a plurality of antennas, the signal supplied to each antenna is a signal obtained by giving a different delay to the modulated signal and further weighting and combining the modulated signal, At least one of the delay amount and the weight coefficient is set to a different value between antennas. According to the present invention, at least one of the delay amount and the weight coefficient in each signal combining unit corresponding to a plurality of antennas provided in one transmitter is made different between adjacent antennas. Thus, the phenomenon that the signal after combination disappears in a specific area, which has conventionally occurred, is prevented.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION In order to explain the present invention in more detail, the present invention will be described with reference to the accompanying drawings. First, the configuration of the wireless communication system according to the present invention will be described. FIG. 1 is a configuration of a first embodiment in a wireless communication system according to the present invention. In FIG. 1, 1 is a transmission information input terminal, 2A and 2B are transmitters, 3 is a receiver, 4A and 4B are modulators, and 5A and 5B are first gain adjusters. Yes, 6A, 6B
Is a delay device, 7A and 7B are second gain adjusters, 8A and 8B are first antennas, 9A and 9B are second antennas, and 10 is an antenna of the receiver 3. .

The radio communication system configured as described above has at least one (here, two) transmitters 2A and 2B for a plurality (here, two for convenience of explanation).
(For convenience of explanation, two antennas are arranged). For example, transmission signals output from antennas 9A and 9B are delayed by delayers 6A and 6A, respectively.
B gives an arbitrary delay (including a case where no delay is given). At this time, the setting is performed so that the corresponding delay outputs between the transmitters have different output powers. Then, each transmitter outputs a transmission signal from each antenna with the set output power. In the present embodiment, two transmitters are used for convenience of description, but the present invention is not limited to this. For example, a configuration using three or more transmitters may be used. In addition, although each transmitter is provided with two antennas, the present invention is not limited to this, and a configuration using one or three or more antennas may be used.

However, the transmitter described in FIG.
This is a configuration having only a concept that plays a particularly important role. For example, if processing such as up-conversion for converting a baseband signal to an RF frequency has already been performed at the time of output from modulators 4A and 4B, , And all of these cases, such as after gain adjustment. Each antenna has a function equivalent to that of a normal antenna, such as a leaky coaxial cable. Also, the modulators 4A and 4B and the delay units 6A and 6B can be simplified in configuration by substituting two functions for one.

As described above, in the present embodiment, an arbitrary delay can be given to each antenna, and at least one delay output between the transmitters is set to have different output power. Therefore, all the signals do not disappear after the combination. In addition, each transmitter sets the antenna radio environment independently,
The improvement in characteristics due to the diversity effect can also be enjoyed. Furthermore, it is possible to set the delay setting to not more than one symbol, and it is possible to greatly reduce the circuit scale of an equalizer (not shown) in the receiver as compared with the related art.

Hereinafter, the operation of the wireless communication system configured as described above will be described. For example, in the transmitter 2A,
After adjusting the output level of the signal to be transmitted by the first gain adjuster 5A, the signal is transmitted to the first antenna 8A.
And a predetermined delay is added by the delay unit 6A, and the output level is adjusted by the second gain controller 7A, and then the signal is transmitted from the second antenna 9A. Similarly, in the transmitter 2B, after adjusting the output level of the signal to be transmitted by the first gain adjuster 5B, the signal is transmitted from the first antenna 8B without delay, and transmitted to the delay unit 6B. After a predetermined delay is added thereto, and the output level is adjusted by the second gain controller 7B, the signal is transmitted from the second antenna 9B. Then, the receiver 3 receives the transmission signals from the four antennas 8A, 8B, 9A, and 9B using the antenna 10, and then performs demodulation processing.

FIG. 2 is a timing chart for explaining radio wave propagation in the radio communication system according to the present embodiment. In the present embodiment, for example,
The delay values of the delay unit 6A and the delay unit 6B are made the same, and
The first gain adjuster 5A (transmitter 2A) and the second gain adjuster 7B (transmitter 2B) have the same gain, and the second gain adjuster 7A (transmitter 2A) and the first gain adjuster 5B (transmitter 2B) has the same gain. Then, the gains of the first and second gain adjusters in each transmitter are set to different values. That is, the gain is set so that the transmission powers of the corresponding delayed outputs (combinations of the first antennas 8A and 8B and the second antennas 9A and 9B) are different between adjacent transmitters. Note that such a setting in the present embodiment is an example of an operation in the wireless communication system of the present invention. For example, as described above, at least one delayed output between the transmitters has different output powers. It may be set so as to be.

Usually, the distance between the first antenna 8A and the second antenna 9A of the transmitter 2A is so small as to be negligible compared to the distance between the transmitters. Similarly, the distance between the first antenna 8B and the second antenna 9B of the transmitter 2B is so small as to be negligible compared to the distance between the transmitters. Therefore, in the case of such a configuration, the condition under which the environment for signal reception is most severe is when the receiver 3 is located between the two transmitters. Further, in the receiver 3, the reception signal level becomes the smallest when the delay values of the delay units 6A and 6B are the same as shown in FIG. And the signal component RB from the first antenna 8B in the transmitter 2B have opposite phases to each other, and the second antenna 9A in the transmitter 2A
This is a case where the signal component RC from the transmitter 2B and the signal component RD from the second antenna 9B in the transmitter 2B have opposite phases.

In the above case, in the wireless communication system of the present embodiment, the gain amounts of the first gain adjuster 5A and the first gain adjuster 5B and the second gain adjuster 7A
Since the gain and the gain of the second gain adjuster 7B are different values, even when the received signals having the same delay amount are input in opposite phases, the received signals are not completely canceled out, and Will remain. Specifically, in FIG. 2, the signal components C with different delay amounts
A and two signals of the signal component CC will remain.

On the other hand, the signal component RC from the second antenna 9A of the transmitter 2A and the second antenna 9B of the transmitter 2B
When the signal components RD and are out of phase with each other and the signal levels of both are the same, the wireless communication system of the present embodiment operates as follows. Note that this condition can occur in an environment where the receiver 3 exists near the transmitter 2A. FIG. 3 is a diagram showing a timing chart for explaining radio wave propagation of the wireless communication system in the above case.

In such a case, the signal component RA from the first antenna 8A and the signal component R from the first antenna 8B
As for B, the level of the signal component RA always increases. Therefore, in the receiver 3, for example, the signal component RC from the second antenna 9A and the second antenna 9B
Are offset by each other,
Since the signal component RA and the signal component RB do not cancel each other, the signal component always remains.

As described above, in the present embodiment, the combination of the transmission power in the delay output (including no delay) from the plurality of antennas of each transmitter is
By making different transmitters adjacent to each other, the signal components of each other do not cancel each other, thus preventing the phenomenon that the signal after combining disappears in a specific area, which occurred in the past. It is possible to do. In addition, by independently setting the radio wave environment of the antenna, it is possible to enjoy the characteristic improvement by the diversity effect.
Further, since it is possible to set the delay setting to not more than one symbol, it is possible to greatly reduce the circuit scale of the equalizer in the receiver as compared with the related art.

FIG. 4 shows the transmitter of the communication system shown in FIG. 1 as a base station (the base stations 31A and 32B shown in FIG. 1).
FIG. 11 is a diagram showing a specific example in a case where the receiver is replaced with a mobile station (corresponding to the mobile station 32), and the wireless communication system of the present invention is applied to communication between a base station and a mobile station. . However, in FIG. 4, two base stations are used for convenience of description, but the present invention is not limited to this. For example, a configuration using three or more base stations may be used. Further, each base station is configured to include two antennas, but is not limited to this, and may be configured to use one or three or more antennas.

FIG. 5 shows the configuration of the second embodiment in the wireless communication system according to the present invention. Note that the same components as those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. In FIG. 5, 2
C and 2D are transmitters, and 11A and 11B are signal combining units. FIG. 6 is a diagram showing a configuration of the signal synthesizing units 11A and 11B. . In FIG.
Is a modulation signal input terminal, 22 is a delay unit, 23
Is a complex weighting unit, 24 is a combining circuit, and 25 is a combined signal output terminal.

The radio communication system configured as described above has at least one (here, two) transmitters 2C and 2D for a plurality (here, two for convenience of explanation).
(For convenience of explanation, one antenna is arranged). For example, the delay signals are respectively given to the modulation signals output from the antennas 12A and 12B by the delay unit 22 (including the case where no delay is given). .
Then, the combining circuit 24 performs weighted combining using the original modulated signal and the modulated signal with an arbitrary delay to generate a combined signal. Then, each transmitter, from each antenna,
The transmission signal is output at the set output power. In the present embodiment, two transmitters are used for convenience of description, but the present invention is not limited to this. For example, a configuration using three or more transmitters may be used. In addition, although each transmitter is provided with one antenna, the present invention is not limited to this, and a configuration using two or more antennas may be used.

However, the transmitter described in FIG.
This is a configuration having only a concept that plays a particularly important role. For example, if processing such as up-conversion for converting a baseband signal to an RF frequency has already been performed at the time of output from modulators 4A and 4B, , And all of these cases, such as after gain adjustment. Each antenna has a function equivalent to that of a normal antenna, such as a leaky coaxial cable.

Hereinafter, the operation of the wireless communication system configured as described above will be described. For example, in the transmitter 2C,
After the signal combining section 11A generates a combined signal by performing the above-described weighted combination on the signal modulated by the modulator 4A, the combined signal is transmitted from the antenna 12A. Similarly, in the transmitter 2D, the signal combining unit 11B
B to generate a synthesized signal by performing the above-described weighted synthesis on the signal modulated by B,
Send from B. Then, in the receiver 3, the antenna 10
To receive the transmission signals from the two antennas 12A and 12B, and then perform demodulation processing.

FIG. 7 is a diagram showing a timing chart for explaining radio wave propagation of the radio communication system according to the present embodiment. In the present embodiment, for example,
After the signal synthesizers 11A and 11B give different delays (here, one is not delayed) to the normal modulation signal, the complex weighting unit 23 performs phase rotation and amplitude adjustment, and the complex weighting is performed. A case where the weighted signal after the execution and the original modulation signal are combined by the combining circuit 24 will be described. Here, the delay unit 2 in the signal synthesis unit 11A is used.
The delay of 2 is one symbol, and the value of the phase rotation / amplitude adjustment of the complex weighting unit 23 (hereinafter referred to as a weight coefficient) is -1 (18
0 degree phase rotation), the delay of the delay unit 22 in the signal combining unit 11B is one symbol, and the complex weighting unit 23
Is 1 (no phase rotation). The setting of the delay amount and the weighting coefficient in each signal combining unit is not limited to the above, and it is sufficient that at least one of the transmitters is different.

In the case of the above configuration, usually, the condition under which the environment for signal reception is most severe is a case where the receiver 3 is located between the two transmitters. However, in the first embodiment, the signal with no delay and the signal with the delay are transmitted from different antennas, so that the phase relationship between the two can take any value. 1
Since the signals are transmitted from one antenna, the phase relationship between them is uniquely determined by the complex weighting unit 10. In such a case, in the wireless communication system of the present embodiment, the signal component RC delayed by the transmitter 2C is always in opposite phase to the signal component RA not delayed by the transmitter 2C.
Since the signal component RD delayed by D is always in phase with the signal component RB without delay, if the signal component RA and the signal component RB are in opposite phases, the signal component RC and the signal component RD must be Have the same phase, and the received signal is not completely canceled but always remains. Specifically, in FIG. 7, the signal component CA and the signal component C
The two signals of C will be combined at the receiver.

As described above, in the present embodiment, at least one of the delay amount and the weight coefficient in each signal synthesizing unit is made different between adjacent transmitters, so that the signal components of each signal are mutually different. Are not canceled out, so that it is possible to prevent the phenomenon that the signal after combination disappears in a specific area, which has conventionally occurred. Further, in the present embodiment, even if each transmitter has a single antenna, the same effects as those of the first embodiment having a plurality of antennas can be obtained. Further, since it is possible to set the delay setting to not more than one symbol, it is possible to greatly reduce the circuit scale of the equalizer in the receiver as compared with the related art.

FIG. 8 shows the transmitter of the communication system shown in FIG. 5 as a base station (the base stations 31C and 32D shown in FIG. 5).
FIG. 11 is a diagram showing a specific example in a case where the receiver is replaced with a mobile station (corresponding to the mobile station 32), and the wireless communication system of the present invention is applied to communication between a base station and a mobile station. . However, in FIG. 8, two base stations are used for convenience of explanation, but the present invention is not limited to this. For example, a configuration using three or more base stations may be used. In addition, although each base station is configured to have one antenna, the present invention is not limited to this, and a configuration using two or more antennas may be used. FIG. 9 is a configuration of a wireless communication system according to a third embodiment of the present invention. Note that the same components as those of the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted. In FIG. 9, 2E is a transmitter, 11C is a first signal synthesizing unit, 11D is a second signal synthesizing unit, and each signal synthesizing unit in the present embodiment is the same as that in the second embodiment. It is the same as FIG.

However, the transmitter described in FIG.
This is a configuration having only a concept that plays a particularly important role. For example, if processing such as up-conversion for converting a baseband signal to an RF frequency has already been performed at the time of output from modulators 4A and 4B, , And all of these cases, such as after gain adjustment. Each antenna has a function equivalent to that of a normal antenna, such as a leaky coaxial cable.

The difference between the present embodiment and the second embodiment is as follows.
That is, two antennas are provided for each of the two transmitters by providing two signal combining units in one transmitter. Therefore, in the present embodiment, at least one of the delay amount and the weight coefficient in each signal combining unit corresponding to a plurality of antennas provided in one transmitter is different between adjacent antennas. By doing so, the same effect as in the second embodiment can be obtained. FIG. 10 shows a case where the transmitter of the communication system shown in FIG.
A is a diagram showing a specific example in which the receiver is replaced with a base station (corresponding to the mobile station 31), and the wireless communication system of the present invention is applied to communication between the base station and the mobile station. is there. 9 and 10, each base station is provided with two antennas. However, the present invention is not limited to this, and a configuration using three or more antennas may be used.

[0043]

INDUSTRIAL APPLICABILITY As described above, the wireless communication system according to the present invention is useful for a wireless communication system such as an automobile telephone and a portable telephone. In particular, signals from a plurality of base stations are mutually transmitted. It is suitable for a wireless communication system that needs to cover a wide area in an environment where it is difficult to receive a signal such as a place where the signals cancel each other. [Brief description of drawings]

FIG. 1 is a configuration of a wireless communication system according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining radio wave propagation of the wireless communication system according to the first embodiment.

FIG. 3 is a timing chart for explaining radio wave propagation in a wireless communication system operating under conditions different from those in FIG. 2;

FIG. 4 is a diagram showing a specific example when the wireless communication system of the present invention is applied to communication between a base station and a mobile station.

FIG. 5 is a diagram showing a configuration of a second embodiment in the wireless communication system according to the present invention.

FIG. 6 is a diagram showing a configuration of signal synthesizing units 11A and 11B.

FIG. 7 is a diagram showing a timing chart for explaining radio wave propagation of the wireless communication system according to the second embodiment.

FIG. 8 is a diagram showing a specific example when the wireless communication system of the present invention is applied to communication between a base station and a mobile station.

FIG. 9 is a diagram showing a configuration of a wireless communication system according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a specific example when the wireless communication system of the present invention is applied to communication between a base station and a mobile station.

FIG. 11 is a diagram showing a configuration of a conventional wireless communication system.

FIG. 12 is a timing chart for explaining radio wave propagation in a conventional wireless communication system.

FIG. 13 is a diagram showing a configuration of a conventional wireless communication system different from FIG. 11;

Claims (11)

(57) [Claims] 1. A wireless communication system in which a plurality of transmitters transmit the same signal at the same frequency and a receiver receives these signals, wherein at least one antenna is arranged for the plurality of transmitters. Radio transmission, wherein an arbitrary delay (including no delay) is given to the antenna, and an output power different from at least one delay output of another transmitter is set for each transmitter. Communications system. 2. In the case where different delays (including no delay) are given to a plurality of antennas in each transmitter as the arbitrary delay, the correspondence between each transmitter and other transmitters 2. The wireless communication system according to claim 1, wherein an output power of a combination different from a delayed output to be set is set. 3. An equalizer in the receiver,
The wireless communication system according to claim 1, wherein a signal transmitted from at least one antenna of each of the transmitters is demodulated. 4. In a wireless communication system in which a plurality of transmitters transmit the same signal at the same frequency and a receiver receives these signals, at least one antenna is arranged for the plurality of transmitters. Further, a signal to be supplied to each antenna is a signal obtained by further weighting and combining the modulated signals by giving different delays, and for each transmitter, the delay amount in the other transmitters or the weight coefficient A wireless communication system wherein at least one is set to a different value. 5. An equalizer in the receiver, wherein:
The wireless communication system according to claim 4, wherein a signal transmitted from at least one antenna of each of the transmitters is demodulated. 6. In a wireless communication system in which a transmitter having a plurality of antennas transmits the same signal and a receiver receives these signals, a signal supplied to the plurality of antennas may be provided with different delays to a modulated signal. A radio communication system characterized in that the signals are further weighted and combined, and at least one of a delay amount and a weighting factor is set to a different value between antennas. 7. An equalizer in the receiver,
The wireless communication system according to claim 6, wherein signals transmitted from the plurality of antennas are demodulated. 8. When a plurality of transmitters transmit the same signal at the same frequency, at least one antenna is arranged, an arbitrary delay (including no delay) is given to the antenna, and A transmitter characterized by setting an output power different from at least one delayed output in the transmitter. 9. As the arbitrary delay, different delays are applied to a plurality of antennas (including a case where no delay is applied).
9. The transmitter according to claim 8, wherein when the value is given, the output power is set to a combination different from that of the corresponding delay output in the other transmitters. 10. When a plurality of transmitters transmit the same signal at the same frequency, at least one antenna is arranged, and a signal supplied to each antenna is further weighted by giving a different delay to a modulated signal. At least one of the amount of delay in the other transmitters or the weighting factor
A transmitter, wherein one of the transmitters is set to a different value. 11. When transmitting the same signal from a plurality of antennas, a signal to be supplied to each antenna is a signal obtained by giving a different delay to a modulated signal and further weighting and synthesizing the signal. A transmitter, wherein at least one of the coefficients is set to a different value.