JP2002325056A - Antenna diversity communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antenna diversity communication equipment in which antenna diversity effect is obtained under frequency hopping system. SOLUTION: The antenna diversity communication unit comprises a plurality of communication paths having antennas 1 and 2, a switching means 3 for selecting one of these communication paths alternatively, an RSSI 8 for measuring signal information indicative of the receiving state of a communication path selected by the switching means, and means 12 for storing the measured signal information wherein the switching means selects a communication path based on the signal information stored in the storage means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna diversity communication apparatus for performing communication by frequency hopping and antenna diversity using a plurality of antennas.

[0002]

2. Description of the Related Art In digital radio communication, a reflected wave, a diffracted wave and the like in addition to a direct wave are superimposed on each other to form a multiplexed wave propagation path. Fading occurs due to the synthesis of many waves having different arrival times, and transmission errors occur. This is one of the factors.

One of the countermeasures against fading due to such a multi-wave propagation path is a spread spectrum communication system.
Direct Sequence (DS) system, frequency hopping (Frequency Hopp)
ing: FH) system and the like are known.

[0004] Among them, the frequency hopping method performs spectrum spreading by switching (hopping) the center frequency of a signal in a certain order.

The case where the hopping speed is higher than the information speed is called a high-speed frequency hopping system, and the case where the hopping speed is lower than the information speed is called the low-speed frequency hopping system.

Among them, in high-speed frequency hopping, 1
One information symbol is transmitted using several frequencies. In the low-speed frequency hopping scheme, a plurality of information symbols are transmitted at one frequency.

[0007] The low-speed frequency hopping method can be configured with a simpler apparatus and has lower transmission efficiency than the high-speed frequency hopping method, but the effect of fading countermeasures can be obtained by using retransmission and an error correction code together. , Wireless LAN and the like.

On the other hand, the antenna diversity is a system in which a plurality of antennas having a low fading correlation are prepared, and the received powers are combined or switched to reduce the fading.

Antenna diversity includes spatial diversity using a plurality of antennas spatially separated, polarization diversity using a plurality of antennas having different polarizations, and directional diversity using a plurality of antennas having different directivities. The present invention relates to antenna diversity.

A method of combining received signals in antenna diversity is a maximum ratio combining method in which received signals are in-phase and weighted by the SN ratio of each received signal, and an equal gain combining method in which each received signal is in-phase and combined as it is. There is a selective combining method for selecting a signal having the maximum reception level among the received signals.

The combining method includes a combining method performed before detection and a combining method performed after detection, depending on at which stage of the receiver the combining is performed. However, these combining methods require a plurality of receivers, and the hardware scale becomes enormous.

As a simpler method, there is an antenna switching method. In the antenna switching method, a plurality of antennas are switched and received by one receiver, and when the reception level falls below a predetermined switching level, the antenna is switched to another antenna and received.

At the time of antenna switching, when the reception level of the switching destination antenna is lower than a predetermined switching level,
As an operation algorithm, SE (Swi
A ch-and-Examie method and an SS (Switch-and-Stay) method in which, once switched, the switched antenna is received as it is, and when the level changes from the switching level to the lower level again, the antenna is switched to another antenna.

Further, domestic TDMA (Time Di)
In a mobile station of a digital mobile phone using a vision multiple access (VMS) system, the reception levels of two antennas are detected and compared in a time slot signal section immediately before the reception of a signal of the own station time slot, and an antenna for switching to a higher level antenna is used. The switching method is used.

FIG. 6 is a schematic block diagram of a conventional antenna diversity communication apparatus. As shown in FIG. 6, this communication device has two antennas 1 and 2 and a switching unit 3
Selects one of the antennas 1 and 2 as an alternative.

LNA (Low Noise Ampli)
The fiber 4 amplifies the signal of the antenna selected by the switching means 3 and outputs the amplified signal to the mixer 5. Also, the mixer 5 includes:
The signals generated by the local oscillator 6 are input, and the mixer 5 mixes these signals and outputs the IF (Inter).
The signal is converted to a mediate frequency (AGC) signal and the AGC (Automatic Gain Cont.
rol) 7. The AGC 7 amplifies the input signal and outputs the amplified signal to the detector.

The switching means 3 switches between the antennas 1 and 2 and receives an RSSI (Received Signal).
A strength indicator (8) measures the signal strength of the antennas (1) and (2) and outputs the measured signal strength to the comparing means (9).

The magnitude comparison is performed in the slot immediately before the own station slot as shown in FIG. 7, and the switching means 3 switches to an antenna having a higher strength in the slot immediately before the own station slot, and performs antenna diversity. Is realized. In this way, antenna switching does not occur within the own station time slot, and noise due to switching can be avoided.

However, in the frequency hopping method,
It is not easy to use this antenna switching method together for the following reason.

[0020]

Generally, in the frequency hopping method, when viewed at one hopping frequency, the signal is a narrow band signal.

Therefore, looking at each hopping frequency,
Despite fading, in the fast frequency hopping scheme, a frequency diversity effect can be obtained by transmitting one information symbol at a plurality of frequencies.

On the other hand, in the low-speed frequency hopping system, since a plurality of information symbols are transmitted at one frequency, it is difficult to obtain a frequency diversity effect. Here, by using retransmission and an error correction code together, transmission quality can be improved, but transmission efficiency is reduced.

To solve such a problem, a method in which antenna diversity is used in combination with a frequency hopping method, particularly a low-speed frequency hopping method, is considered. In particular, using an antenna switching method with a simple hardware configuration and processing is considered.
For example, it is effective in a mobile station or the like.

However, in the frequency hopping method,
When using antenna diversity together, there are the following problems.

Hereinafter, Bluetooth will be described as an example of digital wireless communication using the low-speed frequency hopping method. Note that the present invention can be applied to other than Bluetooth without departing from the gist thereof.

Now, Bluetooth is a standardization organization, Bluetooth SIG (http://www.bluetooth.com).
/ Www. Bluetooth. com), which is a short-range wireless communication standard.
"Jap C. Haartsen," Bluetooth
othTM: A new radio interf
ace providing ubiquitous
connectivity ”, IEEE Vehicle
ar Technology Conference,
Vol. 1, pp 107-111, May 2000 "
And so on.

One time slot is 625 μsec, and the frequency is basically hopped every time slot. The hopping speed is 1600 hop / sec.

Since one packet is transmitted at one hopping frequency, the frequency does not hop in the middle of the packet.

In a use state such as stationary or walking, the reception level fluctuation during reception of one packet is so small that it can be ignored.

Therefore, it is sufficient to perform antenna switching for each hopping frequency when using the antenna switching method together.

However, the last time slot is
Since the hopping frequency is different, the SE method or S
Even if the antenna switching method for detecting, comparing, and switching the reception level of each antenna in the S method or the immediately preceding time slot is applied as it is, the antenna diversity effect cannot be obtained.

In addition, when the antenna reception level is detected and compared within the reception time slot and the antenna is switched, the switching is affected by noise.

Therefore, an object of the present invention is to provide an antenna diversity communication apparatus which can obtain an antenna diversity effect under a frequency hopping scheme.

[0034]

SUMMARY OF THE INVENTION A diversity communication apparatus according to the present invention includes a plurality of communication paths having an antenna, a switching means for selecting one communication path from the communication paths, and a switching means. Comprises reception information measurement means for measuring signal information indicating the reception state of the communication path selected by the user, and storage means for storing the signal information measured by the reception information measurement means, and the switching means includes a signal stored in the storage means. A communication path is selected based on the information.

With this configuration, it is possible to realize an antenna diversity communication apparatus that can obtain an antenna diversity effect under the frequency hopping method.

[0036]

According to the antenna diversity apparatus of the present invention, a plurality of communication paths having an antenna, switching means for selecting one communication path from these communication paths, and this switching means Comprises reception information measurement means for measuring signal information indicating the reception state of the communication path selected by the user, and storage means for storing the signal information measured by the reception information measurement means, and the switching means includes a signal stored in the storage means. A communication path is selected based on the information.

With this configuration, the reception information measuring means measures the signal information on the current communication path and the hopping frequency of the current channel, and stores the signal information in the storage means. Thereby, when hopping to this channel next time, it is possible to refer to the signal information of the storage means. By this reference, after the hop, the reception condition becomes good,
High probability can be guaranteed, fading can be suppressed, and reception quality can be improved. Although this effect is remarkable when using low-speed frequency hopping, the present invention can be combined with high-speed frequency hopping, and in this case, performance improvement can be expected.

In the antenna diversity apparatus according to the second aspect, the signal information stored in the storage means is one or more of a numerical value indicating a reception intensity, a value indicating a good or bad reception state, and a reception error detection result. It is a combination.

According to this configuration, the signal information stored in the storage means accurately represents the reception state, and the antenna can be switched according to the reception state.

In the antenna diversity device according to the third aspect, the storage means stores the measured signal information for all hopping frequencies.

According to this configuration, the storage means stores the signal information at all hopping frequencies, and the reception state can be managed more precisely.

In the antenna diversity device according to a fourth aspect, the switching means switches the communication path when switching the hopping frequency based on the signal information of the next channel stored in the storage means.

With this configuration, the switching of the communication path does not occur within the reception time slot, and the generation of noise can be suppressed.

In the antenna diversity device according to the fifth aspect, the signal information of the corresponding hopping frequency in the storage means is:
It is updated every time the hopping frequency is switched.

With this configuration, the signal information can be updated to cope with a change in the situation such as a movement of the communication device.

In the antenna diversity device according to the sixth aspect, the signal information of the storage means is updated collectively within a range where the correlation with the corresponding hopping frequency is high.

According to this configuration, signal information in a range having a high correlation with the corresponding hopping frequency is collectively updated, the interval at which the signal information is updated is shortened, and the follow-up ability to a change in the situation can be further improved.

In the antenna diversity device according to the seventh aspect, the range in which the signal information of the storage means is updated collectively is variable.

According to this configuration, immediately after the initialization of the storage means, the signal information is updated in a wide range, the certainty of the signal information is improved to some extent, and after about one round of updating,
The signal information can be updated only in a narrow range with high reliability.

In the antenna diversity device according to the present invention, the storage means stores the measured signal information not for all hopping frequencies but for each band obtained by dividing the spread spectrum band.

According to this configuration, the intervals at which the signal information is updated are shortened by grouping the spread spectrum bands for each of the divided bands, and the follow-up performance to a change in the situation can be further improved.

In the antenna diversity device according to the ninth aspect, the switching means relates to a band to which the next channel belongs.
The communication path is switched when the hopping frequency is switched based on the signal information stored in the storage unit.

With this configuration, switching of the communication path does not occur within the reception time slot, and generation of noise can be suppressed.

In the antenna diversity device according to the tenth aspect, the signal information of the corresponding band in the storage means is updated every time the hopping frequency is switched.

With this configuration, it is possible to cope with a change in the situation such as a movement of the communication device.

In the antenna diversity device according to the eleventh aspect, the storage unit stores only the signal information of one communication path selected by the switching unit, and the switching unit stores the signal information of the communication path in a predetermined state. If it is smaller than the value of, switch to another communication path.

With this configuration, the communication path is switched,
The communication state can be improved. Further, the storage capacity of the storage means can be saved.

In the antenna diversity device according to the twelfth aspect, the storage means stores all the signal information of the plurality of communication paths, and the switching means switches to the communication path having the best communication state.

With this configuration, the reception state can be managed more precisely.

In the antenna diversity device according to the thirteenth aspect, in an initial state, a plurality of communication paths are selected with equal probability.

In the initial state, which communication path is used,
It is unclear whether a good communication state will be obtained. Therefore, it is possible to start in an intermediate state in which selection is performed with an equal probability, and then shift to a better communication state.

In the antenna diversity device according to the fourteenth aspect, when communication is not performed continuously for a predetermined time, the storage means returns to the initial state.

If the communication is not performed for a long time, the signal information is not updated for a long time, and when the communication is restarted next time, the situation may change greatly. Therefore, the state is returned to an intermediate state, and thereafter, the state is shifted to a better communication state.

In the antenna diversity device according to the fifteenth aspect, the signal information is the reception intensity of the antenna on the communication path.

With this configuration, the communication state can be accurately represented.

In the antenna diversity device according to the sixteenth aspect, transmission is performed using the antenna of the switched communication path.

If the reception state is good, it is expected that the converse, the transmission state is also good. Therefore, in this way, the transmission state can be improved using the monitoring result of the reception state.

In the antenna diversity device according to the seventeenth aspect, the signal information on the transmission channel of the storage means is:
It is updated using the ACK / NCK information in the reply to the transmission.

With this configuration, the communication information of the transmission time slot can be updated, the update interval can be shortened, and the ability to follow a change in the communication status can be further improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic block diagram of an antenna diversity communication apparatus according to Embodiment 1 of the present invention. In the figure, the same components as those of the prior art shown in FIG.

Now, the communication paths of this embodiment are two systems from the antenna 1 to the switching means 3 and from the antenna 2 to the switching means 3. Of course, three or more systems can be provided. In this embodiment, these two systems perform antenna diversity and simultaneously perform low-speed frequency hopping. However, the present invention can be applied to a case where high-speed frequency hopping is performed.

In FIG. 1, the frequency hopping code generation means 9 generates a hopping code for low-speed frequency hopping.

The synthesizer 10 generates a signal corresponding to the generated hopping code, and outputs the signal to the mixer 5.

The comparison means 11 receives a signal from the RSSI 8 (corresponding to the reception information measurement means) and holds a threshold for judging whether the reception state is good or not. Then, the comparing means 11 compares the threshold with the signal information in magnitude,
If the signal information is smaller than the threshold value, it is determined that the reception state is bad; otherwise, it is determined that the reception state is good.

In this example, the reception information and the threshold are the reception strength. This is preferable because the quality of the reception state can be accurately determined. In addition, the threshold may be set to the minimum reception strength.

However, the reception information only needs to be able to judge the quality of the reception state, and may be, for example, a CRC.

In this example, the storage means 12 stores the received information for each of the hopping frequencies for each of the two communication paths. In this way, the reception state can be managed precisely.

Alternatively, the storage means 12 may store only signal information of one communication path. In this case,
Since the correlation of the communication paths of each system is low, it is possible to cope with only the reception state of one communication path. Because
When the communication state of one communication path is bad, the communication state of the other communication path is good and the probability is high. Therefore, storage of communication information for a part of the system can be omitted. In this way, rational information management can be performed using the correlation while saving the storage capacity of the storage unit 12.

The contents stored in the storage means 12 are initialized in the initial state so that the two communication paths are selected with equal probability.

In this regard, as shown in FIG. 1, taking the case where there are two communication paths as an example, in the initial state, the communication state is good in one of the communication paths and bad in the other. There are cases.

However, in the initial state, it is impossible to know which system is better. For example, in the initial state, if communication is performed entirely with only one system, it is better if this system is good, but if it is bad, communication itself is not established and diversity control becomes impossible. There is a risk.

In the present embodiment, in order to avoid such a situation, in the initial state, instead of deciding on one of the systems, the system starts from an intermediate state in which either system is not used, and shifts to a more preferable state. I decided that.

The above points are applicable to a case where communication is not continuously performed for a certain period of time or more and communication is restarted thereafter.
Therefore, in such a case, in the present embodiment, the storage unit 12 is initialized so as to be similar to the initial state.

The signal information in the storage means 12 is updated by the comparing means 11 every time a hop occurs. At this time, it is possible to update only the signal information related to the hopping frequency, but it is desirable to update the range having a high correlation with the hopping frequency collectively.

More specifically, in Bluetooth, the frequency difference between adjacent channels is 1 MHz, and signal information for three or five channels including adjacent channels is updated collectively.

Since these channels have high correlation, they have a similar communication state with a high probability. If so, the update is collectively performed in this manner, thereby shortening the signal information update interval, and following the change in the reception state (for example, when the communication apparatus moves due to the user moving). Performance can be improved.

Further, (1) the range for updating the signal information is
It is desirable to set a wide range (for example, 10 channels) for a certain time after the storage unit 12 is initialized, and a narrow range (for example, 5 channels) after the lapse of the certain time.

First, immediately after the initialization of the storage means 12, the communication state of the antenna is equal to good or bad. Therefore, in this state, the signal information is updated as widely as possible, and the certainty of the signal information as a whole is increased to some extent than immediately after the initialization. On the other hand, after a certain period of time has passed since the initialization and after a round of updating, the likelihood of the signal information is somewhat higher than immediately after the initialization, so the signal is more reliable and only in a narrow range. Updating the information is advantageous. For this reason, as described above, immediately after initialization,
It is preferable that the range in which the signal information is updated is made variable, for example, narrowed thereafter.

In addition, (2) AC in response to transmission
It is preferable to update the communication information on the transmission channel using the K / NCK information.

In the diversity at the time of reception, measurement and updating of signal information are performed during packet reception, and it is possible to prepare for the next communication using the same channel. However, in diversity at the time of transmission, the signal information cannot be directly measured on the own device side.

For this reason, the ACK in the transmission response
(Acknowledgment) / NCK (no ac
(Knowledgement) information. The ACK / NCK information is normally used in wireless packet communication.

More specifically, when the transmission packet arrives at the destination device without error, the destination device responds by adding ACK information to the packet. At this time, based on the fact that the ACK information is added to the packet, the communication information at the time of transmission related to the ACK information is regarded as “good”.

On the other hand, when the partner device adds NAK information to the packet or when there is no response (even if no response is received), the communication information is regarded as "bad".

By considering the above, it is possible to substantially update the communication information relating to the channel used at the time of transmission, shorten the interval of updating the communication information, and improve the follow-up ability to the change of the communication condition. Can be further improved.

Next, with reference to FIG. 3B, a description will be given of updating of communication information relating to a transmission channel. First, FIG.
The leftmost time slot in (b) is a transmission time slot, and the own device transmits a transmission packet of ch8 to the other device.

The next time slot is a reception time slot, and the own apparatus receives a ch4 reception packet from the other apparatus. The received packet includes A, which indicates whether the transmission status from the own device to the other device in ch8 is good.
CK / NAK information is added.

Therefore, if ACK information can be received in the ch4 reception time slot, the communication information of the preceding ch8 transmission time slot is regarded as "good". Otherwise, the communication information is regarded as “bad”.

Thus, communication information of the transmission time slot of ch8 can be updated during the reception time slot of ch4.

Similarly, in each of the ch8, ch9 and ch4 reception time slots, ch1, ch5 and ch
The communication information of each transmission time slot is updated.

As shown in FIG. 3A, the update of the communication information on the receiving channel is simpler than that in FIG. 3B. At this time, instead of using the ACK / NAK information, the communication information is measured and updated as described above.

That is, in the second reception time slot of ch4 from the left in FIG. 3A, the communication information of the reception time slot of ch4 is updated. Similarly, ch8, ch
9, in each reception time slot of ch4, ch8,
The communication information of each reception time slot of ch9 and ch4 is updated.

Of course, at the time of updating the communication information, it is preferable to update the communication information of not only one channel but also several channels as described above.

In FIG. 1, the switching unit 3 refers to the signal information in the storage unit 12 and selects one of the antennas 1 and 2 as a communication path.

Next, the operation of the antenna diversity communication apparatus according to this embodiment will be described. First, the LNA 4 is connected to the switching unit 3
The received signal of the antenna switched in step is amplified.

The synthesizer 10 reads out the hopping code from the frequency hopping code generation means 9 and generates a signal corresponding to the hopping code.
The signal amplified by the NA 4 and the output of the synthesizer 10 are mixed and converted into an IF signal.

The AGC 7 amplifies the converted IF signal, sends the amplified IF signal to a detector, and performs frequency-hopping reception demodulation.

The comparing means 11 compares the received signal strength measured by the RSSI 8 with a threshold value, and outputs the result of the comparison to the storage means 12. Then, the storage unit 12 stores the comparison result, the current hopping code, and the current antenna selection signal as a set. This selection signal is a signal for controlling which antenna is switched to.

Next, the operation of antenna switching will be described with reference to Blu.
Description will be made with an example of the case of “ethoth”. As shown in FIG. 2, in the case of Bluetooth, transmission and reception time slots are arranged alternately, and frequency hopping is performed for each time slot.

First, the frequency hopping code generating means 9
, The next hopping code is input to the storage means 12.

The switching control means 20 refers to the storage means 12 and acquires the hopping code of the transmission slot and the comparison result and the antenna selection signal stored in association with the code.

If the comparison result is bad, the switching control means 20 selects an antenna different from the acquired antenna selection signal.
Select the same antenna as the antenna selection signal.

The switching control means 20 outputs an antenna selection signal reflecting this selection result to the switching means 3 and causes the storage means 12 to store the signal.

As shown in FIG. 2, this selection signal is maintained during the reception time slot period.

Next, in the reception slot shown in FIG. 2, reception demodulation is performed by the antenna selected by the switching means 3 by the above-described frequency hopping reception method.

During the reception slot, the comparing means 11
The received signal strength measured by the SI 8 is compared with a threshold, and the comparison result is output to the storage unit 12. Then, the storage means 12
Stores the comparison result, the current hopping code, and the current antenna selection signal as a set.

The above operation is performed in each transmission slot and reception slot, and the signal information corresponding to the hopping code and the selection signal are updated as needed for each reception slot.

As a result, an antenna diversity effect can be obtained in a frequency hopping scheme in which the hopping frequency differs for each reception slot.

(Embodiment 2) FIG. 4 is a schematic block diagram of an antenna diversity communication apparatus according to Embodiment 2 of the present invention.

Now, the communication paths of this embodiment are two systems, from the antenna 1 to the switching means 3, and from the antenna 2 to the switching means 3. Of course, three or more systems can be provided. In this embodiment, these two systems perform antenna diversity and simultaneously perform low-speed frequency hopping. However, the present invention can be applied to a case where high-speed frequency hopping is performed.

The antenna diversity communication apparatus of the present embodiment stores the signal strength of the received signal for each of a plurality of divided bands of the spread spectrum band, and, when switching the communication path, determines the divided band to which the previously stored hopping frequency belongs. The communication path is switched based on the signal strength, and the communication path is switched when the hopping frequency is switched. To be updated.

In the present embodiment, the frequency hopping code generation means 9 and the storage
The difference is that a determination means 13 is provided between the two.

The determining means 13 reads out the hopping code from the frequency hopping code generating means 9 and determines to which of the divided bands of the spread spectrum band the hopping code belongs. The determination result by the determination unit 13 is input to the storage unit 12, and the communication path is switched based on the signal strength of the band to which it belongs and the selection signal.

During the receiving slot, the comparing means 11
Compare the received signal strength measured by RSSI8 with a threshold,
The comparison result is output to the storage unit 12. Then, the storage unit 12 stores the comparison result, the current hopping code, and the current antenna selection signal as a set.

Now, in the present embodiment, for dividing the spread spectrum band into a plurality, a fading frequency correlation is used.

Here, the frequency correlation ρ of fading caused by the multipath is generally expressed by

(Equation 1) It can be expressed as.

In equation (1), σ is the delay spread,
Δf represents the frequency difference between two received signals, and as Δf increases, ρ tends to decrease.

When the frequency correlation is large, the fading of two received signals having different frequencies fluctuates in substantially the same manner. When the frequency correlation is small, the fading of the two received signals fluctuates almost independently.

For this reason, there is a high probability that the signal strengths of the respective antennas within a frequency difference having a relatively high frequency correlation are substantially the same.

Therefore, if the band is divided for each frequency difference having a relatively high frequency correlation, only one signal strength of the hopping frequency in the divided band need be stored, and the storage capacity can be saved.

Here, according to the results of measurement of the fading frequency correlation in a general house, the frequency difference at which the frequency correlation value decreases to 0.5 is 10 MHz on average.
It is about.

Taking Bluetooth as an example, the spread spectrum bandwidth is about 80 MHz, and the interval between hopping frequencies is 1 MHz.

Therefore, in this case, the spread spectrum band is set to 1
It is good to divide into 8 bands every 0 MHz.

As described above, by dividing the band,
The signal strength to be stored and the number of selection signals can be reduced. The other points are the same as in the first embodiment.

(Embodiment 3) FIG. 5 is a schematic block diagram of an antenna diversity communication apparatus according to Embodiment 3 of the present invention.

By the way, the communication path of the present embodiment includes the antenna 1,
Up to the LNA 4, the mixer 5, the AGC 7, and the switching means 3,
There are two systems including the antenna 2, the LNA 24, the mixer 25, the AGC 27, and the switching means 3. Of course, three or more systems can be provided. In this embodiment, these two systems perform antenna diversity and simultaneously perform low-speed frequency hopping. However, the present invention can be applied to a case where high-speed frequency hopping is performed.

The antenna diversity communication apparatus of this embodiment stores the signal strength of the received signal for each of a plurality of divided bands of the spread spectrum band and, when switching the communication path, determines the signal of the divided band to which the previously stored hopping frequency belongs. The communication path is switched based on the signal strength. The communication path is switched when the hopping frequency is switched, the signal strength is measured during reception, and information on the divided band to which the hopping frequency belongs is stored in the storage unit. Is to be updated.

In addition, as shown in FIG. 5, in this embodiment,
Unlike the second embodiment, two RSSIs 8 and 28 are provided. Then, the storage unit 33 receives the determination result of determining the belonging band from the determining unit 32, and outputs the signal strengths of the two communication paths of the belonging band to the comparing unit 34.

The comparing means 34 compares the received signal strength measured by the RSSIs 8 and 28 with the threshold value, and outputs the comparison result to the storage means 33. Then, the storage unit 33 stores the comparison result, the current hopping code, and the current antenna selection signal as a set. The storage unit 33 stores two signal intensities in combination with the determined band during the reception slot.

The method of dividing the spread spectrum band into a plurality is the same as in the second embodiment.

By measuring and storing the signal strengths of the two communication paths, it is possible to switch to a communication path having a higher signal strength.

For example, even when the two communication paths both exceed the threshold value, the communication path is switched to a communication path having a higher signal strength, so that the reception quality can be further improved. The other points are the same as in the first embodiment.

[0142]

According to the present invention, an antenna diversity effect can be obtained by applying an antenna diversity method of an antenna switching method or a selective combining method performed before detection in a frequency hopping method. As a result, fading at each hopping frequency can be reduced, and the reception quality can be improved.

Further, since the antenna is not switched within the reception time slot, noise due to the switching does not occur.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an antenna diversity communication apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of the antenna switching timing.

FIG. 3A is an explanatory diagram of updating communication information relating to the same receiving channel; FIG.

FIG. 4 is a schematic block diagram of an antenna diversity communication device according to a second embodiment of the present invention.

FIG. 5 is a schematic block diagram of an antenna diversity communication apparatus according to a third embodiment of the present invention.

FIG. 6 is a schematic block diagram of a conventional antenna diversity communication device.

FIG. 7 is an explanatory diagram of a conventional antenna switching timing.

[Explanation of symbols]

 1, 2 antenna 3 switching means 4, 24 LNA 5, 25 mixer 7, 27 AGC 8 RSSI 9, 30 frequency hopping code generation means 10, 31 synthesizer 11, 34 comparison means 12, 33 storage means 13, 32 determination means

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shoichi Koga 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5K022 EE04 EE31 5K059 BB01 CC02 CC03 DD02 DD05 DD26 DD27 5K067 AA02 BB21 CC10 DD44 DD45 EE02 KK03 KK15

Claims (17)

[Claims] An antenna diversity communication apparatus for performing communication by frequency hopping, comprising: a plurality of communication paths having an antenna; a switching unit for selecting one communication path from the communication paths; A reception information measurement unit that measures signal information indicating a reception state of the communication path selected by the switching unit; and a storage unit that stores the signal information measured by the reception information measurement unit. An antenna diversity communication apparatus characterized in that a communication path is selected based on signal information stored in an antenna diversity communication apparatus. 2. The method according to claim 1, wherein the signal information stored in the storage means is one or a combination of two or more of a numerical value indicating a reception intensity, a value indicating a good reception condition, and a reception error detection result. The antenna diversity communication device according to claim 1, wherein: 3. The antenna diversity communication apparatus according to claim 1, wherein said storage means stores the measured signal information for all hopping frequencies. 4. The antenna diversity communication apparatus according to claim 3, wherein said switching means switches a communication path when switching a hopping frequency based on signal information of a next channel stored in said storage means. 5. The antenna diversity communication apparatus according to claim 2, wherein the signal information of the corresponding hopping frequency in the storage means is updated every time the hopping frequency is switched. 6. The antenna diversity communication apparatus according to claim 5, wherein the signal information in said storage means is updated collectively within a range having a high correlation with the corresponding hopping frequency. 7. The antenna diversity communication apparatus according to claim 6, wherein a range in which the signal information of said storage means is updated collectively is variable. 8. The antenna diversity communication apparatus according to claim 1, wherein said storage means stores the measured signal information not for all hopping frequencies but for each band obtained by dividing a spread spectrum band. . 9. The switching means according to signal information stored in the storage means for a band to which a next channel belongs.
9. The antenna diversity communication apparatus according to claim 8, wherein a communication path is switched when the hopping frequency is switched. 10. The signal information of a corresponding band in the storage means,
10. The antenna diversity communication apparatus according to claim 8, wherein the antenna diversity communication apparatus is updated every time the hopping frequency is switched. 11. The storage means stores only signal information of one communication path selected by the switching means, and the switching means determines that the signal information of the communication path is smaller than a predetermined value. 11. The antenna diversity communication apparatus according to claim 8, wherein the communication path is switched to another communication path. 12. The communication apparatus according to claim 1, wherein said storage means stores all signal information of said plurality of communication paths, and said switching means switches to a communication path having the best communication state. 12. The antenna diversity communication device according to items 11 to 11. 13. An apparatus according to claim 1, wherein said plurality of communication paths are selected with an equal probability in an initial state.
13. The antenna diversity communication device according to items 12 to 12. 14. The antenna diversity communication apparatus according to claim 1, wherein the communication unit returns to an initial state when communication is not performed for a predetermined time. 15. The antenna diversity communication apparatus according to claim 1, wherein said signal information is reception strength of an antenna in a corresponding communication path. 16. The antenna diversity communication apparatus according to claim 1, wherein transmission is performed using an antenna on a switched communication path. 17. The antenna diversity communication apparatus according to claim 1, wherein the signal information on the transmission channel in the storage means is updated using ACK / NCK information in a transmission response.