JP2001333003A - Mobile communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide mobile communication equipment which adopts free-space diversity, is applicable even to faster data communication and receives the spread spectrum signal of a frequency hopping system. SOLUTION: This equipment is provided with a plurality of antennas 11A and 11B and a control part 14 which receives a spread spectrum signal in a full frequency subjected to frequency hopping with the respective antennas, also measures its electric field intensity and stores the electric field intensity in a storing part 15, divides a full frequency band subjected to the frequency hopping into a plurality of bands, selects and decides either of the plurality of antennas 11A and 11B for each divided frequency band on the basis of the electric field intensity stored in the part 15 and makes an incoming signal received by either of the antennas 11A and 11B selected in accordance with the frequency of the incoming signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication device such as a portable telephone for receiving a spread spectrum signal of a frequency hopping method.

[0002]

2. Description of the Related Art Conventionally, there is a diversity space system in which a plurality of antennas are selectively switched to perform communication using an antenna having a better communication state. This spatial diversity system is a technology intended to prevent fading in a narrow band transmission system, and monitors reception power of a plurality of antennas, and switches reception antennas when the reception power falls below a certain threshold, thereby relatively receiving signals. The operation is such that an antenna having a large power is always selected. Basic switching methods include switch and stay, switch and
There are methods such as Examin, and many improvements such as making the threshold variable.

[0003]

As described above, the spatial diversity system is a technology intended for countermeasures against fading in a narrow band transmission system. Therefore, the antenna switching is performed by considering only the fluctuation of the reception power at one specific frequency. However, if this is used as it is in a wide band transmission system such as frequency hopping, good reception cannot always be performed.

This is because, in the frequency hopping method, the frequency of the radio wave received before and after the antenna is switched is different, so that the fluctuation of the electric field strength of the frequency before the switching and the fluctuation after the switching are different.

FIG. 6A shows a state of frequency hopping in a frequency / time / power space in the frequency hopping method. As shown in FIG. 2A, the frequency of an incoming radio wave differs every time, and one frequency is normally hopped once without overlapping in one sequence.

FIG. 6A is a view of FIG. 6A perpendicular to the frequency-power plane as indicated by an arrow V. FIG. 6B shows the frequency range of an incoming radio wave that can be obtained by frequency hopping.

Therefore, in order to perform antenna switching based on spatial diversity in the frequency hopping system,
The antennas are switched at all hopping frequencies, and the electric field strengths before and after each switching are measured, and based on the measurement results, each time the frequency is hopped, the antenna having the higher electric field strength at each frequency must be selected and switched. Must.

[0008] Therefore, there is a problem that it takes time to switch the antenna and cannot be applied to high-speed data communication.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a frequency hopping type spread spectrum signal which employs spatial diversity and is applicable to higher speed data communication. The present invention provides a mobile communication device for receiving a mobile communication device.

[0010]

According to the first aspect of the present invention,
In a mobile communication device that receives a spread spectrum signal of a frequency hopping method, a plurality of antennas, a spread spectrum signal at all the frequencies hopped by each of the plurality of antennas, and a preliminary measurement of the electric field strength thereof are received. Receiving means, determining means for dividing the entire frequency band by the frequency hopping into a plurality, and selecting and determining any one of the plurality of antennas based on the electric field strength measured by the preliminary receiving means for each divided frequency band, Antenna switching means for receiving an incoming signal by an antenna selected corresponding to the frequency based on a result of the determination by the determination means.

With such a configuration, in a mobile communication device that receives a spread spectrum signal of a frequency hopping system, which is a transmission system over a wide band, the switching operation of the antennas is made more compatible with the propagation path characteristics of a plurality of antennas. In addition to the fact that the frequency hopping method has a frequency diversity effect in the first place, while at the same time making it applicable to high-speed data communication at least, it is also necessary to select and receive an antenna with a good reception state by spatial diversity. Can be.

According to a second aspect of the present invention, in a mobile communication apparatus for receiving a spread spectrum signal of a frequency hopping method, a plurality of antennas and a spread spectrum signal at all the frequencies hopped by the plurality of antennas are transmitted. Preliminary receiving means for receiving and measuring the electric field strength, and judging to select and determine the antenna having a larger number of electric field strengths exceeding a predetermined threshold value over all frequencies due to reception by the preliminary receiving means Means, and antenna switching means for receiving an incoming signal with an antenna selected based on a result of the judgment by the judgment means.

With such a configuration, in a mobile communication apparatus that receives a spread spectrum signal of a frequency hopping scheme, which is a transmission scheme over a wide band, a switching operation of the antennas can be performed in accordance with the propagation path characteristics of each of the plurality of antennas. In addition to the fact that the frequency hopping method has a frequency diversity effect in the first place, it is possible to select and receive an antenna with a good reception state by spatial diversity while making it applicable to higher speed data communication. it can.

According to a third aspect of the present invention, in the second aspect of the present invention, the determining means selects and determines an antenna having a better reception state using a plurality of threshold values.

With such a configuration, in addition to the operation of the second aspect of the present invention, depending on the manner of setting the threshold value,
It is possible to set an optimum communication environment according to a required level, for example, when it is only necessary to perform communication at a minimum, or when it is desired to perform communication of a signal of higher quality and less noise.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) The present invention will be described below with reference to, for example, a frequency hopping spread spectrum method based on Bluetooth (a wireless LAN technology based on the IEEE 802.11 standard; hereinafter, referred to as "Bluetooth"). A first embodiment when applied to a receiving device that receives a signal will be described with reference to the drawings.

FIG. 1 shows a part of the circuit configuration of the receiving system, in which 11A and 11B are used for space diversity.
It is a book antenna. 2.45 [MHz] ISM (Ind) received by these antennas 11A and 11B, respectively.
usual Scientific Medica
l) Only one of the band signals is selected by the switching unit 12 and sent to a demodulation circuit (not shown) where it is subjected to processing such as despreading and demodulated. It is also sent to the unit 13.

The received power detector 13 detects the electric field strength of the received signal at the antenna 11A or 11B transmitted via the switching unit 12 as a power level value, and outputs the detection result to the controller 14. .

The control unit 14 is composed of a CPU, a ROM storing an operation program thereof, a RAM as a work memory, and the like. The control unit 14 controls the operation of the entire receiver. The switching unit 12 includes the antennas 11A and 11B. In addition to transmitting a control signal for switching and selecting either one, the power level of the received signal received from the received power detection unit 13 is stored in a pair with the reception frequency information indicating the hopping frequency transmitted from the circuit of the demodulation system. The antenna to be selected is determined based on the content stored in the storage unit 15.

Next, the operation of the above embodiment will be described.

FIG. 2 shows the contents of the spatial diversity operation process executed by the control unit 14 at predetermined time intervals. In the figure, at the beginning of the process, first, a signal for one sequence of hopping frequency (79 channel frequencies with a hopping width of 1 [MHz]) is continuously received in a state where the antenna 11A is switched and selected by the switching unit 12. The power level of the received signal obtained by the received power detection unit 13 is stored in the storage unit 15 as a reception characteristic of the antenna 11A in combination with the reception frequency information (step A01).

Next, the switching unit 12 controls the antenna 11B
In a state in which the switching is selected, similarly, a signal for one sequence of the hopping frequency is received, and the power level of the reception signal obtained by the reception power detection unit 13 is paired with the reception frequency information to receive the signal by the antenna 11B. The characteristics are stored in the storage unit 15 (step A02).

FIG. 3A illustrates a channel characteristic representing the reception environment of the antenna 11A. When a signal for one sequence is received with such a channel characteristic, the power level of each received signal becomes The result is as shown in FIG.

Similarly, FIG. 3B shows the antenna 11B
FIG. 3 (4) shows an example of the propagation path characteristics representing the reception environment. When a signal for one sequence is received with such propagation path characteristics, the power level of each received signal is as shown in FIG. .

Here, for example, assuming that the frequency range of one sequence of the hopping frequency is substantially equally divided into three blocks (frequency bands) as shown in FIGS. 3 (3) and (4). And two antennas 11
After detecting the level of the received signal over the entire frequency range of each of A and 11B, first, an initial value "1" is substituted for a variable n representing a block (step A03), and reception is performed by the antenna 11A in the block 1. It is determined which of the power level of the received signal and the power level of the signal received by the antenna 11B is relatively higher (Step A).
04).

If it is determined that the power level of the signal received by the antenna 11A is relatively higher than the power level of the signal received by the antenna 11B, the antenna 11A of the block 1 Assuming that the reception state is good, the identification signal indicating the antenna 11A corresponding to the block 1 is stored and set in the storage unit 15 (step A0).
5).

On the contrary, if it is determined that the power level of the signal received by the antenna 11B is relatively higher than the power level of the signal received by the antenna 11A, , Assuming that the reception state is good, the identification signal indicating the antenna 11B corresponding to the block 1 is stored and set in the storage unit 15 (step A06).

After the setting process of one of steps A05 and A06 is completed, the value of the variable n representing the block is updated and set to "+1" (step A07), and the updated value is set to one sequence of the hopping frequency. After confirming that the total number N of the blocks (frequency bands) obtained by dividing the frequency range over (Step A08)
The processing from step S04 is repeated again using the updated variable n.

By repeatedly executing the processing of steps A04 to A08 in this manner, information for identifying the antenna having a better reception state is stored and set in the storage unit 15 for the remaining blocks.

When the setting process for all the divided blocks is completed, and it is determined in step A08 that the value of the variable n which has been further updated and set exceeds the total number N of blocks, the blocks stored and set in the storage unit 15 are thereafter set. A control signal is transmitted to the switching unit 12 as necessary so as to switch and select an antenna corresponding to the hopping frequency according to the antenna identification information and the antenna corresponding to the hopping frequency. A09) The antenna switching based on the antenna identification information set in the storage unit 15 is performed to wait for the lapse of time (step A10). Return to the processing of.

As described above, the two antennas 11A, 11A
B. In accordance with the respective propagation path characteristics, an appropriate antenna is switched and selected for each block of the divided frequency band, so that within the block of the same frequency band, the antenna relatively resembles the propagation path characteristic of the antenna. It is possible to reduce the number of antenna switching operations compared to the case of performing the switching operation for each frequency. You can select and receive.

In this embodiment, for ease of explanation, the number of blocks (frequency bands) dividing the entire hopping frequency band is three, but the present invention is not limited to this. Instead, it can be set appropriately according to the step width of the hopping frequency and the number of all frequency channels.

(Second Embodiment) Hereinafter, a second embodiment in which the present invention is applied to a receiving apparatus for receiving a spread spectrum signal of a frequency hopping system conforming to Bluetooth, for example, will be described with reference to the drawings. I do.

The basic circuit configuration of the receiving system is the same as that shown in FIG. 1, and the same reference numerals are used for the same portions, and illustration and description thereof are omitted.

Next, the operation of the above embodiment will be described.

FIG. 4 shows the content of the operation processing of the space diversity executed by the control unit 14 every predetermined time. In the figure, at the beginning of the process, first, a signal for one hopping frequency sequence (79 channel frequencies with a hopping width of 1 [MHz]) is continuously received with the switching unit 12 switching and selecting the antenna 11A. The power level of the received signal obtained by the received power detection unit 13 is paired with the received frequency information and stored in the storage unit 15 as the reception characteristics of the antenna 11A (step B01).

Next, the switching unit 12 controls the antenna 11B
In a state in which the switching is selected, similarly, a signal for one sequence of the hopping frequency is received, and the power level of the reception signal obtained by the reception power detection unit 13 is paired with the reception frequency information to receive the signal by the antenna 11B. The characteristics are stored in the storage unit 15 (step B02).

FIG. 5A illustrates propagation path characteristics representing the reception environment of the antenna 11A. When a signal for one sequence is received with such propagation path characteristics, the power level of each received signal becomes The result is as shown in FIG.

Similarly, FIG. 5 (2) shows the antenna 11B
FIG. 5 (4) shows an example of propagation path characteristics representing the reception environment. When a signal for one sequence is received with such propagation path characteristics, the power level of each received signal is as shown in FIG. .

Here, for example, assuming that the threshold of the power level of the received signal is as indicated by Th in FIGS. 5 (3) and (4), in particular, the signal of one sequence received by the antenna 11A It can be seen that the power level is below the threshold Th at two channel frequencies.

However, in the control unit 14, the antenna 11A
For each of the one-sequence signal received at step S11 and the same signal received at the antenna 11B, the number of signals exceeding the threshold Th is measured (step B03), and based on the measurement results. Two antennas 1
Which of 1A and 11B has a better reception state is determined by, for example, the threshold value Th based on a reception signal received by the antenna 11A.
It is determined whether or not the number exceeding the number is greater than the same number received by the antenna 11B (step B04).

Here, if it is determined that the number of reception signals received by the antenna 11A that exceeds the threshold Th is larger, the switching unit 12 determines that the reception state of the antenna 11A is better than that of the antenna 11B. Sends a control signal to
It is assumed that this antenna 11A is selected.

On the other hand, if it is determined that the number of reception signals received by the antenna 11B that exceeds the threshold Th is greater, the switching unit 12 determines that the reception state of the antenna 11B is better than that of the antenna 11A. Sends a control signal to
It is assumed that this antenna 11B is selected.

In step B05 or B0
Using the antenna 11A or 11B selected in Step 6, while performing reception by an antenna having a better reception state (Step B07), waiting for a predetermined time to elapse (Step B08), and determining that the time has elapsed Then, the process returns to the process from step B01.

As described above, the two antennas 11A and 11A
B corresponding to each propagation path characteristic, and a preset threshold T
h, so that an antenna capable of receiving a signal having a power level exceeding h is switched and selected. You can select and receive.

In the above-described embodiment, the number of preset threshold values is one. However, the present invention is not limited to this. It is also possible to set a certain level and a plurality of levels such as a level at which a higher quality signal with less noise is transmitted and received, and to provide an optimal communication environment according to the content of the signal to be transmitted and received.

In the configuration shown in FIG. 1, two antennas 1 are used to configure a space diversity system.
1A and 11B, but this is also 2
The number is not limited to three, and may be three or more.

Further, both the first and second embodiments of the present invention have been described in connection with the case where the present invention is applied to a receiving apparatus for receiving a spread spectrum signal of a frequency hopping method based on Bluetooth. The present invention is not limited to this, and can be applied to any mobile communication device that receives a spread spectrum signal of a frequency hopping system, as long as a spatial diversity system is constructed by a plurality of antennas. Of course there is.

In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0050]

According to the first aspect of the present invention, in a mobile communication apparatus for receiving a spread spectrum signal of a frequency hopping scheme which is a transmission scheme over a wide band, the mobile communication apparatus corresponds to the propagation path characteristics of each of a plurality of antennas. It is possible to select and receive an antenna with a good reception state while reducing the switching operation and applying to higher-speed data communication.

According to the second aspect of the present invention, in a mobile communication apparatus for receiving a spread spectrum signal of a frequency hopping system which is a transmission system over a wide band, an antenna switching operation corresponding to the propagation path characteristics of each of a plurality of antennas. , And can be applied to higher-speed data communication, and can select and receive an antenna with a good reception state.

According to the third aspect of the present invention, in addition to the effect of the second aspect of the present invention, depending on how the threshold value is set, it is sufficient that communication can be performed at a minimum, or noise can be improved with higher quality. An optimum communication environment can be set according to a required level, for example, when it is desired to perform communication of a signal with few signals.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing processing contents of spatial diversity according to the embodiment;

FIG. 3 is a diagram illustrating an operation according to the embodiment.

FIG. 4 is a flowchart showing processing contents of spatial diversity according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an operation according to the embodiment.

FIG. 6 is a diagram for explaining a spread spectrum signal of a frequency hopping method.

[Explanation of symbols]

 11A, 11B ... antenna 12 ... switching unit 13 ... reception power detection unit 14 ... control unit 15 ... storage unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J021 AA02 AA05 AA06 CA06 DB04 FA31 GA02 HA05 HA10 JA03 5K022 EE04 EE11 EE31 5K059 CC03 DD02 DD07 DD27 EE02 5K067 AA23 BB02 CC10 CC24 EE02 FF16 GG11 KK03

Claims (3)

[Claims] 1. A mobile communication apparatus for receiving a spread spectrum signal of a frequency hopping method, comprising: a plurality of antennas; receiving a spread spectrum signal at all the frequencies hopped by each of the plurality of antennas; Preliminary receiving means for measuring the intensity, dividing the entire frequency band by the frequency hopping into a plurality, and selecting and determining any one of the plurality of antennas based on the electric field strength measured by the preliminary receiving means for each divided frequency band A mobile communication device, comprising: a determination unit that performs a determination based on a result of the determination, and an antenna switching unit that receives an incoming signal with an antenna selected according to the frequency. 2. A mobile communication apparatus for receiving a spread spectrum signal of a frequency hopping method, comprising: a plurality of antennas; receiving a spread spectrum signal at all the frequencies hopped by each of the plurality of antennas; Preliminary receiving means for measuring the strength; determining means for selecting and determining the antenna having a greater number of electric field strengths exceeding a predetermined threshold value over all frequencies by receiving with the preliminary receiving means; And an antenna switching means for receiving an incoming signal with an antenna selected based on the result of the determination in (1). 3. The mobile communication apparatus according to claim 2, wherein said determination means selects and determines an antenna having a better reception state using a plurality of threshold values.