JP2003152633A - Radio communication system and portable radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein it is difficult to miniaturize portable radio equipment since an electromagnetic shield part is to be provided conventionally for reducing electromagnetic noise. SOLUTION: By controlling a transmitting time in the base station of the radio communication system, the phases of a clock supplied to the digital part of the portable radio equipment and a received signal are synchronized. The portable radio equipment supplies the error information of the clock and the received signal to the base station. On the basis of this clock error information, the base station corrects the time of transmission to the portable radio equipment and performs transmission. Thus, the oscillator and the crystal vibrator of the portable radio equipment do not require frequency synchronizing operation and clock synchronizing operation in the digital part and the portable radio equipment can be composed of the oscillator and the crystal vibrator simplified rather than conventional one so that miniaturization is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication field, and more particularly to a wireless communication system for realizing a small, lightweight and low cost wireless device and a portable wireless device used therein.

[0002]

2. Description of the Related Art Generally, a portable wireless device is required to be compact and lightweight for easy carrying. In addition, lowering the price of terminals is also a problem in order to increase the number of users. In order to solve these problems, it is necessary to reduce the number of parts and the system load.

First of all, a shield material is mentioned as a component which hinders downsizing, weight reduction and cost reduction of portable radios. Hereinafter, a conventional technique for the shield will be described.

Usually, a radio device is generally shielded. The purpose of this shield is roughly divided into
(1) to prevent unnecessary radio waves inside the terminal from radiating to the outside (unwanted radiation to the outside of the housing), and (2) to block interference waves that enter the inside of the wireless device from outside the terminal. It can be roughly divided.

The reason why the shield in the case of (1) is necessary will be described. FIG. 15 is a diagram for explaining a phenomenon in which unnecessary radio waves inside the self terminal are radiated to the outside. In FIG. 15, the parts that may emit unnecessary radio waves include a high frequency frequency synthesizer (1520) that is an oscillation source, an intermediate frequency stage oscillator (1521), and a reference clock oscillator (152
2) etc. To give a specific frequency, the reception frequency (1523 part) 1.9 GHz band (transmission speed is 2
Taking a cordless phone (about 00 Kbps) as an example,
Transmitting / receiving first intermediate frequency (1524 part) is 200-
If it is a radio | wireless machine of 300 MHz and the transmission / reception 2nd intermediate frequency (1525 part) is about 50-100 MHz, the high frequency frequency synthesizer (1520) will be 1.6-1.7.
Approximately GHz, the intermediate frequency stage oscillator (1521) is 150
The frequency is about 200 MHz. Further, in a mobile phone with a reception frequency of 900 MHz band (transmission rate of about 40 Kbps), the above value is about half the value. Since the reference clock oscillator (1522) having a transmission speed of about 100 times is used, the frequency of the cordless telephone is about 20 MHz and the frequency of the mobile telephone is about 4 MHz.

In a wireless communication system in which such a wireless device is used, wireless terminals of the same system in the vicinity are the same for all terminals, not to mention the wireless frequency band (1523), and even if the manufacturers of the terminals are different. Also, the first and second intermediate frequencies (1524,
1525) is likely to be used. Therefore, the above-mentioned high frequency frequency synthesizer (1520), intermediate frequency stage oscillator (1521), reference clock oscillator (152
2) If all three leak to the outside of the housing (1527), they become an interference wave for other wireless terminals, which lowers the so-called C / I and causes deterioration of the reception state.

Next, a situation where the radiation from the housing affects the radio will be described from the viewpoint of the time axis. FIG. 2 is a diagram showing a frame structure of TDMA communication of the wireless communication system.
Here, it is assumed that the terminal A is a radio device that generates unnecessary radio waves and the terminal B is a radio device that is affected by unnecessary radio waves. In this figure, R1, R2, and R3 are reception slots (201), T1,
T2 and T3 (202) are transmission slots, for example,
When it is received in the R1 slot, transmission is performed in the T1 slot, so-called ping-pong transmission (TimeDivision).
Ion Duplex: TDD) is assumed.
Here, the frames of the terminals in the system are synchronized (203), and the reception slots (2
01) and the transmission slot (202) do not overlap in time. Even in such a case, when the oscillation sources (120, 121, 122) built in the terminal have the same frequency as described above, radio wave interference occurs between the terminal A and the terminal B.
For example, even when each terminal (terminals A and B in this example) is in the reception R1 state, the high frequency frequency synthesizer (120),
Since the intermediate frequency oscillator (121) and the reference clock oscillator (122) are in the operating state, unless the oscillation source of the terminal A is sufficiently shielded, as shown in FIG. ) And terminal B (304) are close to each other, terminal A (303) to terminal B
Radiation of unwanted radio waves (305) occurs in (304), and terminal B
The reception characteristics of are degraded. Normally, in the TDD system, the receiving slots R1, R2, R3, etc. are separately allocated to each terminal, and therefore, during a normal call, for example, the terminal A is R
1 and terminal B are assigned different slots such as R2, and such interference between terminals does not pose a problem.

However, when each terminal is in a standby state, each terminal is in a paging state for receiving a control signal (302) transmitted from the radio base station (301) to all terminals. In such a case, different terminals may be receiving the same reception slot (for example, R1), which may cause radio wave interference as described above. Needless to say, it is necessary to provide a shield to reduce unnecessary radiation from the oscillation source, and conversely, it is also necessary to provide a shield to the terminal B to reduce unnecessary radio waves to the terminal A. Nor.

The above is the interference at the time of reception, but naturally, also at the time of transmission, radio wave interference due to unnecessary radiation occurs between terminals, and this is radiation after the radiation itself has been amplified by a power amplifier, etc. The emission level is larger than that of the reception level, which is a larger problem than the reception level. For example, in FIG. 2, the transmission frame (2
02), when the terminal A and the terminal B are transmitting using the same T1 slot, for example, the terminal A and the terminal B are close to each other, and the shielding effect against unnecessary radiation radiated to the outside by the mutual terminals is provided. If not enough, for example, unwanted radiation from the terminal A enters the wireless unit through the gap between the antenna (1501) of the terminal B or the outside of the housing (1527) such as an interface connector, a microphone, and a speaker (1526). , A high frequency synthesizer of terminal B (152
0) and the power amplifier (1512) and the like, causing problems such as deterioration of transmission modulation accuracy and deterioration of C / N of the high frequency synthesizer.

The frequencies that may be radiated to the outside of the housing of the radio device as described above include the frequencies such as the radio frequency, the intermediate frequency, and the clock frequency, as well as the harmonic frequency and the low frequency of the oscillation source of these frequencies. Wave frequencies and other secondary and third-order components newly generated by these components and non-linear distortion of the radio section
Higher-order nonlinear distortion components such as the 4th, 5th, and so on are considered, and these are generally called spurious emissions.

The shield for preventing unnecessary radio waves inside the own terminal from radiating to the outside has been described above in (1), but conversely, it is necessary to reduce the interference of external radio waves by (2 It goes without saying that this is a shield that is used to prevent interference waves from entering the inside of the radio from outside the terminal.

As described above, the shield is indispensable also in the radio equipment used in the radio communication system in which the synchronization state is generally maintained through the slave terminal.

As described above, the radio device is usually provided with a shield for a portion that radiates radio waves or a portion that is not resistant to interference waves. Shielding is performed by covering a necessary portion with a conductor based on the principle of electrostatic shielding, which is called electromagnetism. At this time, in order to complete the shield, in principle, it is necessary to cover the required portions without gaps with a conductor having a high conductivity.

Since other radio communication systems, televisions, radio broadcast waves, etc. have different radio frequency bands, the band filters and channel selection in the radio frequency band and the intermediate frequency band provided in a normal radio device are provided. Although it can be sufficiently reduced with a filter, etc., as described above, in order to reduce unnecessary radio waves from radio equipment used in close frequency bands in the same system, the frequency of the desired wave and the unnecessary wave should be reduced. Since they are close to each other or almost the same, it is impossible to use the bandpass filter as described above. Therefore, in the past, in order to prevent the interference wave, there was no choice but to provide a shield.

However, even if the shield is applied, it is effective to shield unnecessary radiation of interference waves in the intermediate frequency band (1524, 1525) which is not directly connected to the antenna (1501), but it is effective even if the shield is applied. Regarding the interference in the frequency band, there is a problem that even if the outer casing is covered with a shield, unnecessary radiation is generated from the antenna (1501), and it is difficult to maintain the shielding effect.

Further, the intermediate frequency band (1524, 152
As for the unwanted radiation of 5), there is also a problem that it is radiated from the antenna to the outside of the housing by wrapping around (1501) from the power supply line to the antenna inside the housing.

Moreover, such a shield material is usually heavier as the effect thereof is increased.
It needed to be big, thick, or multi-ply, and wasn't a good fit for a handheld device where very cheap, small, and lightweight were desirable.

Next, FIG. 4 shows a connection diagram of actual parts in a conventional portable radio device, and a conventional shielding method performed there will be described.

In the conventional portable wireless device, the components 401 and 402 constituting the device are connected by the conductor wiring 403,
Transmission of signals between parts was performed by electrical means. When the length of the wiring for transmitting a signal by such an electric means is 1 [m], then 1 / n [m]
For an AC signal having a wavelength of (n is a natural number), since the conductor wiring 403 serves as an antenna, a wavelength of 1 / n [m] (n is a natural number) is included in an unnecessary signal passing through the wiring 403. When the AC signal contained therein is included, it is radiated from the wiring 403 and deteriorates the characteristics of other parts in the device and other devices. On the other hand, if unnecessary signals are mixed in from the outside of the device,
If an AC signal having a wavelength of / n [m] (n is a natural number) is included, it is mixed from the wiring 403, which adversely affects the operation of components and deteriorates the characteristics of the device.

Therefore, conventionally, as shown in FIG. 5, a shield 501 made of a material having a high conductivity is used for a component composed of a single or a plurality of parts, or for the entire device.
It was covered with an electromagnetic shield to prevent unwanted signal radiation or mixing, and deterioration of characteristics was prevented by performing electrostatic shielding based on the principle of electromagnetics. The effect of such electrostatic shielding increases as the thickness of the conductor increases and the sealing rate of the shield increases. However, in order for a component to transmit a signal to another component, it is necessary to provide an interface with the outside. Since a signal to be transmitted is passed through such an interface portion, it cannot be covered with a shield, and the shield 501 always needs a hole 502 necessary for connection with the outside, which reduces the sealing rate of the shield. Unwanted signal 503 is radiated from the inside of the shield to the outside of the shield through the hole 502. Also,
On the contrary, the unnecessary signal 504 mixed from the outside passes through the hole 502 and mixes into the shield, which adversely affects the operation of the component.

By the way, in order to enhance the effect of the shield, there is a method of further increasing the thickness of the shield, but it is sufficient for the deterioration of the effect of the shield caused by the low sealing rate. You cannot get the shield effect. In such a case, as shown in FIG. 6, a method of covering a single shielded component or a plurality of shielded components 601 transmitting signals to each other with a shield 602 made of a material having high conductivity. Can also be considered. With such a shield, a higher shield effect can be obtained as the number of layers is increased.

However, there is always a hole 603 for providing an interface with the outside, including the outermost part of such a shield, and it is not possible to create a completely sealed state. It cannot be shielded. Further, the more the shield becomes thicker and the more it is multiplexed, the more effective it becomes, but the volume, weight, and cost increase, which is inconvenient for a portable wireless device that requires performance such as small size, light weight, and low cost. .

Although the shield has been mentioned above as a component that prevents the portable wireless device from being downsized, an oscillator is another component that prevents the portable wireless device from being downsized and reduced in price, like the shield. Next, a conventional technique for this reference oscillator and reference oscillator will be described.

Generally, a radio device is provided with an oscillation circuit which is generally used for frequency conversion of transmission / reception and a reference clock signal of a digital section. This oscillator circuit is generally composed of an oscillator, a tuning circuit, an amplifier circuit, etc., and a crystal oscillator, a ceramic oscillator, etc. are used as a highly accurate reference oscillator. It will be explained how such oscillators provided in the radio impair the miniaturization of the radio.

FIG. 7 is a diagram for explaining the configuration of a conventional radio device. In the block diagram of FIG. 7, the upper half is the receiving system and the lower half is the transmitting system. In the following description, parts that are not particularly necessary are omitted. This radio is shown in Figure 7
It has five oscillators 01 to 705.

The operation principle of transmission / reception of this radio will be described focusing on the roles of these five oscillators. Since the radio frequency signal received by the antenna (706) is normally incapable of channel selection filtering and A / D conversion in the radio frequency band, the frequency is gradually converted to a lower frequency that can be processed by these. First, the low-noise amplifier (707) gives a required gain for improving the NF of the wireless device, and then the first frequency conversion is performed. This operation is performed in the frequency converter (mixer) (708) by multiplying the received radio frequency signal by the reference oscillator (701). Here, the oscillator (701) is usually a frequency synthesizer that can tune the frequency to a desired reception channel. This frequency synthesizer
It is well known that the wireless unit is a particularly large and expensive component. The signal frequency-converted to the first intermediate frequency is amplified (709) and then frequency-converted again to a lower frequency. For this purpose, the frequency converter (7
In 17), the desired signal is multiplied by the reference signal supplied from the receiving second intermediate frequency converting oscillator (703) to form a low frequency signal that can be processed. After that, a low frequency amplifier (710) gives a desired gain, and then the signal is sent to a digital signal processing unit (711) for signal processing. A clock oscillator (705) for supplying a reference clock signal to the digital signal processing unit is required.

On the other hand, on the transmitting side, modulation (716) is performed by the digital signal generated by the digital processing unit (711), and this time, an operation of frequency converting this signal into a radio frequency band is performed. It is sufficient if the frequency can be converted to the radio frequency band at one time, but since the gain and selectivity obtained in one intermediate frequency stage are limited, the frequency is normally converted to the radio frequency band in the same manner as in the case of reception. It First, in the transmission intermediate frequency mixer (715), multiplication with the reference signal supplied from the transmission intermediate frequency conversion oscillator (704) is performed. After this signal is amplified by the transmission intermediate frequency amplifier (714), the transmission high frequency mixer (713) further multiplies the radio carrier signal supplied from the transmission radio section frequency conversion oscillator (702) to obtain a desired radio frequency. Convert frequency to band. This signal is amplified by the transmission power amplifier (712) and then radiated into the air from the antenna (706).

The specific frequencies of the above-mentioned radio frequency and intermediate frequency are as follows. In a cordless telephone having a reception frequency of 1.9 GHz band (transmission speed is about 200 Kbps), the first transmission / reception first intermediate frequency is 200 to 300 MHz,
If the transmission / reception second intermediate frequency is about 50 to 100 MHz, the high frequency synthesizer (701) has a frequency of 1.6 to
About 1.7 GHz, 1 intermediate frequency stage oscillator (702)
The frequency is about 50 to 200 MHz. Further, in a mobile phone with a reception frequency of 900 MHz band (transmission rate of about 40 Kbps), the above value is about half the value. At this time,
In the case of so-called TDD in which transmission and reception are performed at the same frequency, transmission and reception high-frequency frequency synthesizers (701 and 70)
2) Further, the intermediate frequency conversion oscillators (703 and 704) can be shared.

However, in the TDMA and FDMA systems which are normally used in mobile phones and the like, the oscillators 701, 702, 703 and 70 have different transmission and reception frequencies.
Different 4 are required. Further, since the reference clock oscillator (722) having a transmission rate of several hundred times is used, the frequency of the cordless telephone is about 20 MHz and the frequency of the mobile telephone is about 4 MHz. Furthermore, the reference clock oscillator is used when intermittent reception (battery saving) is performed to reduce the power consumption of the radio.
There are cases where two types of clocks are prepared, a clock for operating the digital section and a lower frequency clock for the clock function, and two types of clock oscillators are also required. If there are more modes, the number of oscillators will increase. Therefore, it can be seen that at least 6 oscillators are required even in the ordinary radio device shown in FIG.

Each of these oscillators requires a crystal oscillator (ceramic oscillator at low frequencies), and since these oscillators have no resistance to external interference,
It is usually provided with a metal cap shield, which makes it unsuitable for a very compact and lightweight radio in terms of volume and weight. In addition, the absolute accuracy of clock frequency and reference carrier frequency required for mobile phones and cordless phones in recent years is on the order of a few ppm, and such high-accuracy oscillators are particularly common in wireless devices alongside filters. It is an expensive part. In a portable wireless device, such oscillators and oscillators are likely to be large, and it is difficult to satisfy the electrical characteristics equivalent to those of conventional ones in the case of miniaturization.

In the above, the shield and the oscillator which prevent the miniaturization and the price reduction of the portable wireless device have been described. further,
In the following, the transmission power control performed by the portable wireless device,
It will be explained that the transmission power control increases the physical volume of the portable wireless device, which hinders downsizing and cost reduction of the portable wireless device.

Normally, when carrying data such as voice on radio waves for communication, a relay device such as a base station is commonly used by many users at the same time, and each user can efficiently construct a communication line. Multiple access may be used. As one of the methods for realizing this method, as shown in FIG. 8, a band usable for communication is frequency-divided so that the spectrum (801) used by each user does not overlap on the frequency axis. FDMA (Fr
sequence Division Multiple
There is an Access method. Since this FDMA has the best track record in the system currently used, the hardware is sufficiently developed. Also, there is no need to adjust the timing of the line.

However, in many places such as urban areas where the population is large, many users use the terminal, but since the usable frequency band is limited, the line is congested and the terminal cannot be used. . As a method for solving the above problem, as shown in FIG. 9, TDMA (Time Division Multi) in which each user sequentially sets communication lines by dividing time using the same frequency band
There is an Apple Access method. In this, the transmission timing is controlled so that the signals do not overlap on the repeater, the time slots (901) are switched, and the information is extracted in a time division manner in the demodulation. The modulation method is generally P
The SK method is used.

As another method, as shown in FIG. 10, a large number of users perform communication by spreading the spectrum (1001) on a wideband spectrum of the same frequency and superimposing the spectrum (1001) on each other to perform channel identification. CDMA (C
ode DivisionMultiple Acce
ss) method. This allows random access and widens the power spectrum of the signal to obtain processing gain for removing interference. In addition, the repeater with a hard limiter acts as an ideal AGC for the broadband phase-modulated signal.

Here, transmission power control is required on the wireless terminal side in order to effectively use the capacity for communication. This is because, if the transmission power control is not performed on the wireless terminal side, the terminal close to the base station and the terminal far from each other whose power received by the base station is close to each other are large and the terminals far from each other are small. Therefore, even when the reception power of the terminal far from the base station is despread, it is buried in the power of the terminal close to the base station. Therefore, if there is one terminal in the immediate vicinity of the base station, the terminals in the other zones cannot call because of this one terminal. Therefore, it is necessary to control the transmission power on the side of the wireless terminal so that the call can be made. Further, considering the communication capacity, the communication capacity becomes maximum when the received powers at the base stations are equal.

However, in Patent No. 5056
When the transmission power control is performed based on the control signal from the base station as indicated by 109, it is impossible for the base station to equalize the reception power spectrum of all terminals. Therefore, the capacity is considerably deteriorated. Also,
When controlling the power from a near terminal to a distant terminal, the power must be controlled within a considerable range, which increases the system load. Therefore, when communication is performed in a state where frequency efficiency is high using CDMA, power control is required, which is a system load. Further, finely controlling the transmission power is one of the causes of impairing the miniaturization of the portable wireless device.

Further, an antenna for a portable wireless device, which is important for downsizing the wireless device, will be described. A portable wireless device, for example, a portable wireless device having a function of transmitting and receiving information transmitted via radio waves requires an antenna as a part for exchanging radio waves with space. This is large because the antenna mounted at a position away from the housing for interaction with the outside requires strength and the like. Therefore, the miniaturization of the antenna is required to miniaturize the wireless device.

Usually, as an antenna of a portable radio device,
A monopole antenna as shown in FIG. 11 or another name whip antenna is used. Since this antenna structure is simple and low in cost, it is widely used. However, this monopole antenna is a rod-shaped antenna element (1101) having a length of ¼ wavelength of a desired frequency.
Is mounted in a form that pops out from the portable wireless device body,
It has the drawback that it is easily damaged when carrying or operating.

As an antenna that compensates for the drawbacks of such a monopole antenna, there is a coaxial antenna, which is a modification of a half-wavelength dipole antenna classified as one of the same linear antennas as shown in FIG. 12, and a so-called sleeve antenna. This antenna has a choke effect for high frequency current due to the cylindrical conductor (1203) having a length of ¼ wavelength. The surrounding appearance is protected by a fiber-reinforced plastic pipe that takes into consideration low loss and strength against high frequencies. Furthermore, a built-in type antenna is adopted, and when a call is made, a rod-shaped antenna is pulled out and used, and when it is carried, it can be stored to avoid damage during carrying.

However, this antenna structure has problems that it has a complicated structure and that it is difficult to give flexibility to the antenna element itself. Further, when the antenna is operated even if the antenna element is strengthened, it becomes the outside of the radio device terminal, so that there is a problem of possibility of damage and characteristic deterioration due to excessive addition.

In order to improve this problem, a method of incorporating an antenna element inside the housing can be considered. As a built-in antenna, as shown in FIG.
There are two built-in plate-shaped inverted F antennas and an S-shaped antenna in which the band of the built-in plate-shaped inverted F antenna as shown in FIG. 14 is improved. This is an L-shaped antenna in which a linear element is added to the top of the monopole antenna to lower the height of the antenna, and an inverted F antenna in which a folded structure is added to this, and the top element is made into a plate shape. Inverted F antenna. Also,
An S-shaped antenna is a plate-shaped T-shaped antenna that is a combination of two L-shaped antennas and two inverted-F antennas. These antennas are advantageous for downsizing, and since there is no protrusion outside the radio terminal, stable operation can be realized and there is no risk of damage.

However, in the conventional radio terminal, only the antenna element is built in the finite volume in which the antenna is present, and it is separated from the portion for processing the signal transmitted / received from the antenna. . For this reason, a transmission line that connects the signal processing portion to the antenna element is required, and a finite area is required on the substrate on which the package or module is mounted for this transmission line. As a result, the wireless terminal becomes large. Also, as the frequency used for communication increases, the transmission line loss becomes very large. For this reason, systematic addition to the wireless terminal becomes large from the viewpoint of output power and reception sensitivity.

Therefore, as the frequency used increases, the loss due to the connection between the antenna and the IC also increases, and the area for that is required. In order to solve these problems, a small and simple antenna construction method has been desired.

[0044]

Therefore, in a portable wireless device, such a shield material is not necessary at all, or even if a shield material is needed, it is electrically connected by a shield method simpler than before. There has been a demand for a small and inexpensive wireless device having a shield effect similar to that of a conventional portable wireless device.

The present invention provides a method of shielding that is simpler and more effective than conventional ones, and is small, lightweight, inexpensive, and has excellent characteristics such that unnecessary signal radiation or interference from an external unnecessary signal is small. The purpose of the present invention is to provide a portable wireless device.

In a portable radio device, such an oscillator and oscillators are not required at all, or even when they are required, they are simpler and smaller in size than conventional ones, and electrically It has been desired to develop a small and inexpensive wireless device having the same function as the model equipped with. Also CDM
When communication is performed using A in a state where the frequency efficiency is good, power control is necessary, which is a system load. From the viewpoint of downsizing the terminal, a method without transmission power control has been demanded.

Therefore, as the frequency used increases, the loss due to the connection between the antenna and the IC also increases, and the area for that is required. In order to solve these problems, a small and simple antenna construction method has been desired.

[0048]

In a radio communication system in which a first mobile station and a second mobile station communicate with each other via a plurality of radio base stations according to the present invention, the mobile station is the mobile station of the mobile station. Means for detecting the frequency error between the reference signal and the carrier signal, and means for detecting the phase error between the reference signal and the received signal of the mobile station, the radio base station to the frequency error information from the mobile station. And a means for correcting the carrier frequency based on the phase error information from the mobile station.

Further, in the portable radio used for digital communication of the present invention, frequency error detection means for detecting the frequency error information between the carrier frequency and the reference signal transmitter provided in the radio communication terminal, and the reference signal. A frequency divider circuit that receives the output of the generator and outputs a clock signal of a predetermined frequency,
It is characterized in that a phase error detecting means for detecting phase error information between the output clock signal of the frequency dividing circuit and the received signal is provided.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION Next, TDMA-TDD and TDM.
A wireless communication system according to the present invention and a portable wireless device used therein which are effective for wireless communication adopting the A system will be described with reference to FIG. FIG. 27A shows TD
It is a figure which shows the time-axis (time slot) of two mobile radio | wireless apparatuses, the slave station A, and the slave station B which are wirelessly connected to a certain base station of the MA-TDD system. Here, it is assumed that the slave station A and the slave station B transmit and receive radio waves from the same base station, and it is assumed that slot synchronization between the two frames shown in FIG. To do. Here, the slave station in the system belongs to any one slot of T1 to T4 (R1 to R4) in the figure, and when transmitting in the T1 slot, it receives in the R1 slot.

In the example of FIG. 27, it is assumed that the slave station A and the slave station B both belong to the slots of T1 and R1 and transmit and receive at the same time. At this time, since the slave stations A and B are connected to the same base station, transmission / reception using the same frequency cannot be performed. Therefore, a base station is provided with a synthesizer (reference signal generator) capable of outputting a plurality of frequencies for wireless communication. Here, if the radio frequencies (carrier frequencies) used by the slave stations A and B are different,
There is no concern that radio wave interference will occur between the slave stations A and B.
This is because the frequencies of the carrier wave oscillators used by each other are different. However, in addition to this carrier frequency, as the oscillators used by both the slave station A and the slave station B, there are a reference clock oscillator in the digital section and a reference oscillator for frequency conversion in the intermediate frequency band. Frequencies are often common to each slave station, so
When the slave stations A and B are very close to each other, radio wave interference between the oscillators of these two slave stations becomes a problem unless each slave station has a very perfect shield.

An embodiment of a wireless communication system according to the present invention and a portable wireless device used therein made in view of this point will be described with reference to FIGS. 27 (b) and 16. In FIG. 16, the slave station A (2602) and the slave station B (2603) are
Two portable radios that can interfere with each other. The base station 2601 communicates using a beam-shaped radio wave (2606) emitted from the directional antenna 2607, and the positions of the slave station A (2) and the slave station B (3) within the wireless zone. Is aware of. Here, slave station A (2)
And the slave station B (3) are present in an area close to each other, and when it is determined that the radio wave interference between the oscillators of the two slave stations becomes a problem, among the T1 to T4 (R1 to R4), In the active area (2606), a free slot that is not used by the slave station is searched, and the slave station B is searched for T in the subsequent communication, for example.
2. Issue an instruction to communicate using the R2 slot.
Then, the slot allocation to the slave station B is changed, and the slot (T1, R1) used so far is changed to the slot (T2, R2) as shown in FIG. Subsequent communication is performed with the slave stations within. After receiving the slot change command from the base station, the slave station B performs wireless communication with the base station in slots T2 and R2. Normally, the slave station adopts battery saving that stops the operation of the oscillator and the like except for the transmission / reception slots (T2 and R2 in the case of the slave station B) that are self-assigned. Does not interfere with. Therefore, even when the slave stations A and B in FIG. 16 do not have such a perfect shield, the radio wave interference between the slave stations does not pose a problem.

Further, in the present invention, the fact that the two slave stations are close to each other is detected by using the directional antenna.
Alternatively, the position of the local station may be detected by the slave station using a GPS system or the like, and the position of the local station may be transmitted to the base station. After that, the base station side uses this information to detect a nearby slave station, and if the two slave stations use the same time slot, the slot change is performed,
Communication with the slave stations in the directional area may be performed using the directional antenna.

As described above, according to the present invention, in a wireless communication system, adjacent slave stations are detected, and the time slots for transmission and reception are changed for these slave stations as needed. Therefore, the problem of interference between adjacent slave stations is eliminated, and the shield material that was conventionally required to prevent radio wave interference between portable radios can be removed from the radio as much as possible, so the terminal component cost, There is an effect that the assembly cost can be reduced, and the terminal can be made smaller and lighter.

In the present description, the TDMA-TDD is taken as an example, but the present invention is not limited to the TDMA-TDD, and it is apparent that the same can be used in a normal TDMA system. Is.

FIG. 17 is a diagram for explaining an embodiment of a wireless communication system using a portable wireless device and its terminal according to the present invention. Normally, when communication is performed using CDMA, the base station (5601) which is received by the base station (5601) is used.
Since the received power from the terminal (5602) close to 601) and the received power from the terminal (5602) far from the base station are different, the signal transmitted from the terminal far from the base station is transmitted from the terminal close to the base station. It is buried in the received signal (Near Far Effect). Therefore, transmission power control is required in the portable wireless device (5602).

However, as shown in FIG. 17, the terminal (56
By switching the time slot (5606) to be used according to the received electric field strength in 02), communication using CDMA is possible without controlling the transmission power. Base station (56
Each terminal (5602) receives the control signal from (01). The time slot (5606) used for communication is switched according to the strength of the received power, and the power transmitted by the terminal (5602) included in each time slot (5606) is transmitted from another terminal (5602). Do not be buried in the transmission power of. Since a plurality of terminals (5602) close to the base station (5601) transmit with the same power, the receiving side receives with substantially the same power. The same applies to the remote terminal (5602). Therefore, the received data from each terminal (5602) is not buried in the power from the other terminals (5602). Therefore, transmission power control is not necessary, the system load on the terminal (5602) is reduced, and the portable wireless device (560
This is effective for downsizing in 2).

Further, as shown in FIG. 18, the base station (570
By checking the received power of the control signal from 1),
The time slot is switched regardless of the distance from the base station (5701). The A4 zone (5706) is a portion where the radio wave environment is bad and the received electric field strength is low, so that communication is performed using the T3 time slot (5707) instead of the T2 time slot (5707). Therefore, the terminal (5
On the side of 702), the same communication can be performed even in a portion where the radio wave environment is bad, only by switching the time slot (5707).

FIG. 19 is a diagram for explaining an embodiment of a wireless communication system using a portable wireless device and its terminal according to the present invention. When the radio terminal (5802) moves to the zone of the adjacent base station (5801), the adjacent base station (5
Handoff with 801) is normally done. At this time, the outermost zone (5805) of each base station (5801)
5808) and the mobile wireless device (5802) uses the time slot corresponding to the outermost zone of the base station (5801) only when the mobile wireless device (5802) is used.
802) determines whether to perform handoff. When the time slots A1, A2, A1 ′, and A2 ′ close to the base station (5801) are used, the communication with only one base station (5801) is performed without determining the presence or absence of handoff. Further, only when the time slots A3 and A3 'are used, the radio waves from the two base stations (5801) are received and superposition is performed. At this time as well, when a time slot close to the base station (5801) is used, this process is not performed.

Next, regarding the oscillator and the crystal unit provided in the portable wireless device, a concrete configuration of the portable wireless device which can be realized by a simpler and smaller device than the conventional one, and such a portable wireless device can be used. An embodiment of the present invention relating to a wireless communication system will be described with reference to FIGS.

FIG. 21 shows an example of a communication system used by the portable wireless device provided by the present invention, and FIG. 22 shows an example of a configuration of an upstream signal received by the portable wireless device provided by the present invention. Oscillator and crystal unit 60 provided in the portable radio
The reference signal output from 02 is supplied to the frequency converter 6003, and upon reception, frequency signals of the radio frequency and the intermediate frequency are converted into the intermediate frequency and the base band, respectively. Further, during transmission, the intermediate frequency and the baseband are frequency-converted into an intermediate frequency and a radio frequency, respectively. The other of the reference signals is supplied to the digital section 6004, and the frequency is divided by the digital section for use. Usually an oscillator,
The oscillation frequency of the crystal unit 6002 needs to be synchronized with the carrier frequency of the reception signal to suppress the deterioration of reception sensitivity due to a frequency error. Further, it is necessary that the clock frequency-divided in the digital section 6004 is symbol-synchronized with the received signal to suppress deterioration of receiving sensitivity due to a clock phase error.

In this embodiment, the frequency at which the oscillator of the portable wireless device and the crystal unit 6002 oscillate is unique to the portable wireless device. Therefore, when the call quality is deteriorated due to the frequency error between the base station and the portable wireless device, the base station 60
01 synchronizes the carrier wave frequency with the oscillation frequency of the oscillator of the portable wireless device, the crystal oscillator 6002, and transmits. Reference numeral 6005 in FIG. 21 is a modulation signal modulated by the carrier frequency. The carrier frequency is the frequency converter 600 in the portable radio.
A value is selected so that the intermediate frequency whose frequency is converted in 3 becomes a predetermined value. When performing frequency conversion to the baseband, the carrier frequency is set so that the center frequency after conversion becomes zero. For this purpose, the oscillation frequency information of the oscillator of the portable wireless device and the crystal oscillator 6002 is required. this is,
When the frequencies used in the uplink and the downlink are the same as in TDD, it can be obtained by extracting the carrier wave from the signal received by the base station 6001. Further, when the used frequency is different between the upstream and the downstream, it becomes possible by notifying the base station side of the frequency that the portable wireless device desires to receive.
The received signal 6005 is frequency-converted by the frequency converter 6003. When frequency conversion is performed, the received carrier frequency f1 and the oscillation frequency f of the oscillator or crystal unit are usually used.
The frequency is converted into a frequency difference with 2. In this embodiment, f2
Is a value peculiar to the portable wireless device, so (f1-f
In order to set 2) to a predetermined value, it is sufficient to properly set the center frequency of the reception signal of the portable wireless device. For the sake of simplicity, I explained the case where frequency conversion was performed only once,
The same applies when the frequency conversion is performed a plurality of times.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the base station 6001 controls the transmission time to establish phase synchronization between the clock supplied to the digital unit 6006 and the received signal. The portable wireless device supplies error information 6005 between the clock and the received signal to the base station. The base station corrects the transmission time to the portable wireless device based on this clock error information and transmits. According to the present embodiment, the oscillator and the crystal oscillator of the portable wireless device do not require the frequency synchronizing operation and the clock synchronizing operation in the digital section. Therefore, it is possible to configure with a simpler oscillator and crystal oscillator than the conventional one.

Next, with reference to FIG. 23, a concrete configuration example of the portable radio device according to another embodiment of the present invention will be described. FIG. 23
Indicates the receiving side of the portable wireless device. The received signal received by the antenna is frequency-converted by the frequency converter 6201,
A low pass filter 6202 extracts a desired signal, and then a demodulation circuit 6204 extracts a modulated signal. In this embodiment, the clock phase error detection is performed by a filter that passes only the clock phase error detection signal inserted in the received signal. The detected clock phase error information is transmitted to the base station, and the transmission time is corrected based on the error information to perform clock synchronization in the portable wireless device.

Next, FIG. 24 shows an example of the signal form used in this embodiment. The received signal received by the mobile wireless device of the present invention shown in FIG. 23 is input to 6305a, and the clock phase example 6203 output by the clock oscillator 6203 of the mobile wireless device at this time is 6
305b shows an output signal example of the filter 6205 6305.
It is shown in c. As shown by 6305a in FIG. 24, the received signal has a clock error detection signal at a time interval (1 / fck) corresponding to the clock frequency fck of the portable wireless device.
Therefore, the clock phase error information can be extracted at the interval 1 / fck by passing the received signal through the filter 6305 whose spectrum matches the clock error detection signal. The filter output shows a monotonically increasing characteristic near the clock phase error detection signal. Therefore, it is possible to obtain error information between the clock phase and the received signal by sampling the filter output in the error detection circuit 6206 shown in FIG.

Next, FIG. 25 shows an example of the clock error detection method.
Will be described in detail. It is assumed that the configuration example of the clock error detection unit in the portable wireless device is the same as that shown in FIG. That is, an example of the received signal configuration of the portable wireless device 6406
The output signal of the filter 6205 in FIG.
23b, clocks synchronized with the clock oscillator 6203 of FIG. 23 are shown at 6406c, 6406d, and 6406e, respectively. The filter output is ε0 in the clock phase error detection section.
Shows a monotonically increasing characteristic. The error detection circuit samples the filter output signal with the supply clock and outputs it as error information.

If the output of the error detection circuit is ε when the received signal and the clock are synchronized, the output of the error detection circuit is (ε + Δε +) when the clock is delayed by ΔΦ− time from the received signal. ). Similarly, when the clock leads the received signal by ΔΦ + time, (ε-Δε-)
Is output. This error information is transmitted to the base station, and clock synchronization is performed by correcting the transmission time on the direct side of the base. For example, when the error information is (ε-Δε-),
Send by sending ΔΦ + time earlier. Conventionally, in order to perform a finer clock phase in a portable wireless device, a clock that is faster and more accurate than a desired clock rate is required. Even high-quality calls are possible.

Next, a configuration example of the upstream signal used for the clock synchronization of the present invention will be described with reference to FIG. In the present invention, since the clock phase is not extracted in the portable wireless device,
At the start of communication, the base station needs to know the clock phase of the portable wireless device. FIG. 26 shows a configuration example of the upstream signal. FIG. 26A is an example of an upstream signal configuration for the purpose of detecting the clock initial phase at the start of communication. FIG. 26
(B) is an example of an upstream signal configuration in a steady state. The shaded area is the clock phase error detection signal. In the steady state, the clock is roughly synchronized, so the error detection interval τ
er is shortened and the error detection section is lengthened at the start of communication. 26. By setting the time constant of the phase error detection filter of the portable wireless device in correspondence with the error detection section τer, FIG.
Obtain the filter output shown in. Filter output is time τer
Shows a monotonically increasing characteristic, and error information is obtained by sampling the filter output with the clock in the portable wireless device as shown in the embodiment in FIG. The longer the detection time, the more tolerant the estimated phase error is and the more stable the error information can be obtained. In the present embodiment, the time length of the error detection signal to be inserted in the upstream signal is made variable depending on the clock synchronization state, and the time constant of the phase error detection filter in the corresponding portable radio device is made variable, thereby changing the line state. There is an advantage that flexible synchronization settings can be made according to the requirements. Further, in this embodiment, the insertion position of the error detection signal into the upstream signal is performed every clock time. However, it goes without saying that the error information can be detected at a time interval corresponding to an integral multiple of the clock to be synchronized.

[0069]

As described above, the base station of the wireless communication system controls the transmission time to establish the phase synchronization between the clock supplied to the digital section of the portable wireless device and the received signal. The portable wireless device supplies the error information between the clock and the received signal to the base station. The base station corrects the transmission time to the portable wireless device based on this clock error information and transmits. According to this method, the oscillator and the crystal oscillator of the portable wireless device do not require frequency synchronization operation and clock synchronization operation in the digital section. Therefore, it is possible to configure with a simpler oscillator and crystal oscillator than the conventional one.

As a result, in the wireless communication system according to the present invention and the portable wireless device used therein, there is an effect that the terminal can be made compact, lightweight and low cost.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a portable wireless device according to the present invention.

FIG. 2 is a diagram for explaining a conventional portable wireless device.

FIG. 3 is a diagram for explaining a conventional portable wireless device.

FIG. 4 is a diagram for explaining radiation and mixing of unnecessary electric signals due to wiring between components.

FIG. 5 is a diagram for explaining a conventional portable wireless device.

FIG. 6 is a diagram for explaining a multiplexed electrostatic shield.

FIG. 7 is a diagram for explaining a conventional portable wireless device.

FIG. 8 is a diagram for explaining FDMA.

FIG. 9 is a diagram for explaining TDMA.

FIG. 10 is a diagram for explaining CDMA.

FIG. 11 is a diagram for explaining the structure of a monopole antenna.

FIG. 12 is a view for explaining the structure of a sleeve antenna.

FIG. 13 is a view for explaining the structure of a built-in inverted F antenna.

FIG. 14 is a diagram for explaining the structure of an S-shaped antenna.

FIG. 15 is a diagram for explaining a shield.

FIG. 16 is a diagram for explaining an embodiment of a wireless communication system according to the present invention,

FIG. 17 is a diagram for explaining a control method for switching time slots according to received power from a base station.

FIG. 18 is a diagram for explaining a case where there is a portion where the radio wave environment is bad.

FIG. 19 is a diagram for explaining a case where a terminal performs a handoff.

FIG. 20 is a diagram for explaining a case where a terminal performs a handoff.

FIG. 21 is a diagram for explaining a configuration example of a communication system according to the present invention.

FIG. 22 is a diagram for explaining the operation of the portable wireless device according to the present invention.

FIG. 23 is a diagram for explaining a configuration example of a portable wireless device according to the present invention.

FIG. 24 is a diagram for explaining the operation of the portable wireless device according to the present invention.

FIG. 25 is a diagram for explaining a clock phase error detection method for a portable wireless device according to the present invention.

FIG. 26 is a configuration example of an upstream signal of a wireless communication system according to the present invention.

FIG. 27 is a diagram for explaining slots of the wireless communication system according to the present invention.

[Explanation of symbols]

101 ... Package, 102 ... Pin 201 ... Receiving slot, 202 ... Transmission slot 203 ... Terminal A and terminal B synchronization 301 ... Radio base station, 302 ... Paging signal, 30
3, 304 ... Portable wireless device (slave station), 305 ... Interference wave 401 ... Component 402 ... Component 403 ... Wiring between components 404 ... Electric signal radiated from wiring 405 ... Wiring An electrostatic signal 502 mixed in with the electrostatic shield 502 an interface hole 503 an unnecessary signal radiated from the shield hole 504 an interference signal 506 mixed from the shield hole ..Electrically shielded component 602 ... Electrostatic shield 603 ... Interface hole 701 ... Receiving first intermediate frequency conversion oscillator 702 ... Transmission radio frequency conversion oscillator , 703 ... Receiving second intermediate frequency converting oscillator, 704 ... Transmitting intermediate frequency converting oscillator, 705 ... Reference clock oscillator, 706 ... Antenna,
707 ... Low noise amplifier, 708 ... First intermediate frequency mixer, 709 ... Reception first intermediate frequency amplifier, 710 ... Reception second intermediate frequency amplifier, 711 ... Transmission / reception (digital) signal processing unit 712 ... Transmission power amplifier, 713 ... Transmission High frequency mixer,
714 ... Transmission intermediate frequency amplifier, 715 ... Transmission intermediate frequency mixer 716 ... Modulator, 717 ... Second intermediate frequency mixer 801 ... Frequency spectrum 901 ... Time slot 1001 ... Frequency spectrum 1101 ... Antenna element 1102 ... Ground, 110
3 ... Feed line 1201 ... Coaxial line 1202 ... Ground 1203 ...
Cylindrical conductor 1301 ... Plate antenna element 1302 ... Ground, 1
303 ... Feed line 1401 ... Antenna element, 1402 ... Feed section 1501 ... Antenna, 1502 ... Send / receive switch,
1503 ... High frequency filter, 1504 ... Low noise amplifier, 1505 ... High frequency mixer, 1506 ... Reception first intermediate frequency filter, 1507 ... Reception first intermediate frequency amplifier, 1508 ... Intermediate frequency mixer, 1509 ... Reception second intermediate frequency filter, 1510 ... reception second intermediate frequency amplifier, 1511 ... transmission and reception (digital) signal processing unit,
1512 ... Transmission high frequency filter, 1513 ... Transmission power amplifier, 1514 ... Transmission high frequency mixer, 1515 ... Transmission second intermediate frequency filter, 1516 ... Transmission second intermediate frequency amplifier, 1517 ... Transmission intermediate frequency mixer, 1518 ...
Transmission first intermediate frequency filter, 1519 ... Modulator, 15
20 ... High frequency frequency synthesizer, 1521 ... Intermediate frequency stage oscillator 1522 ... Reference clock oscillator, 1523 ... Transmission / reception radio frequency, 1524 ... Intermediate frequency, 1525 ... Intermediate frequency, 1526 ... Speaker, 1527 ... External housing 2601 ... Base station, 2602 ... Child station A, 2603 ...
Slave station B, 2604 ... Downlink signal, 2605 ... Uplink signal,
2606 ... Directional beam, 2607 ... Directional antenna 5601 ... Base station, 5602 ... Portable wireless device, 5603 ...
A1 zone 5604 ... A2 zone, 5605 ... A3 zone 5606 ... Time slot 5701 ... Base station, 5702 ... Portable radio, 5703 ...
A1 zone 5704 ... A2 zone, 5705 ... A3 zone 5706 ... A4 zone, 5707 ... Time slot 5801 ... Base station, 5802 ... Portable radio, 5803 ...
A1 zone 5804 ... A2 zone, 5805 ... A3 zone 5806 ... A1 'zone, 5807 ... A2' zone 5808 ... A3 'zone 6001 ... Base station, 6002 ... Oscillator, crystal oscillator,
6003 ... Frequency converter, 6004 ... Digital section,
6005 ... Modulation signal, 6006 ... Phase error information 6101 ... Received signal, 6102 ... Reference oscillation frequency, 6
103 ... Received signal at intermediate frequency or baseband,
6104 ... Filter at intermediate frequency or baseband 6201 ... Frequency conversion circuit, 6202 ... Received signal selection filter, 6203 ... Clock supplying oscillator, crystal oscillator, 6204 ... Digital signal processing circuit, 620
5 ... Clock phase error detection filter, 6206 ... Phase error detection circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Arai             One share at 3-1, Asahigaoka, Hino City, Tokyo             Ceremony Company Toshiba Hino Factory (72) Inventor Hiroshi Tsurumi             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center F-term (reference) 5K011 DA03 DA05 DA27 EA02 FA07                       GA04 JA01                 5K067 AA03 AA05 AA42 BB04 DD02                       DD25 DD30 EE02 EE10 GG01                       GG11

Claims (2)

[Claims] 1. A radio communication system in which a first mobile station and a second mobile station communicate with each other via a plurality of radio base stations, wherein the mobile station transmits a reference signal and a carrier signal of the mobile station. Means for detecting a frequency error and means for detecting a phase error between the reference signal and the received signal of the mobile station, wherein the radio base station corrects the carrier frequency based on the frequency error information from the mobile station. And a means for correcting the transmission time of the transmission signal based on the phase error information from the mobile station. 2. In a portable wireless device used for digital communication, frequency error detecting means for detecting frequency error information between a carrier frequency and a reference signal transmitter provided in the wireless communication terminal, and a reference signal generator. A portable radio device comprising a frequency divider circuit which receives an output as an input and outputs a clock signal of a predetermined frequency, and phase error detection means for detecting phase error information between the frequency divider circuit output clock signal and the received signal. .