JP2002135663A - Transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of EMI on another equipment by changing a data amount step by step. SOLUTION: The remaining data amount of a FIFO data buffer 10, which is obtained by subtracting a data amount transmitted by a speed change part 18 from a data amount inputted to the FIFO data buffer 10, is compared with a data amount which is transmitted with the speed change part 18 and, then a data rate judging part 15 judges the raising/reducing of a data rate according to the comparison result. A data rate generating part 16 reports rate information to the speed change part 18, based on the judgement so that speed is changed by the rate. Also, an amplifying part 20 changes amplification degree according to the rate information. Thus data is transmitted step by step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting apparatus, and more particularly to an effective transmitting apparatus when the amount of data to be transmitted changes instantaneously.

[0002]

2. Description of the Related Art Conventionally, TDMA (Time Division) which is widely used in wireless communication devices such as mobile phones.
In the Multiple Access method, since the transmission power is periodically turned on and off as shown in FIG. 9, the amount of data to be transmitted instantaneously changes greatly.

However, recently, CDMA (Code Division M), which is used in IS-95 and the like, has been proposed.
As in the case of the multiple access (multiple access) method, communication is basically performed with the transmission power kept on.
A type in which the amount of data does not change significantly instantly is becoming mainstream.

As described above, as a wireless communication system in which the amount of data to be transmitted changes, a system in which a certain amount of data is transmitted intermittently, such as a TDMA system, or a system in which transmission power is output, such as a CDMA system ( Some methods change the amount of data (per burst), and others change the data transmission rate and modulation rate.

In the TDMA system, the amount of data to be transmitted is changed by changing the burst length. In the CDMA system, the data amount is changed by changing the spreading factor while keeping the bandwidth constant. . Further, in the method of changing the transmission speed and the modulation speed, the data amount is changed by changing the bit rate and the baud rate to increase the bandwidth.

As a prior art for performing wireless communication by changing the transmission speed, the configuration of a data communication method with a variable transmission speed disclosed in Japanese Patent Application Laid-Open No. 60-254942 is shown in FIG.
Shown in In FIG. 10, reference numeral 106 denotes an antenna, 104 denotes a wireless device, 105 denotes a demodulation circuit, and 101 denotes a signal processing device. Also, 10-1 is a first modulation circuit having a transmission rate of 300 baud, 10-2 is a second modulation circuit having a transmission rate of 600 baud,..., 10-n is an nth modulation circuit having a transmission rate of n baud. Of the first modulation circuit switching means 1 according to the switching signal from the signal processing device 101.
02, the output signal is changed to the second modulation circuit switching means 103
Has been switched respectively.

Next, the operation of the data communication method in which the transmission rate is variable shown in FIG. 10 will be briefly described. In FIG. 10, the signal received from antenna 106 is radio 1
04 and the signal processing device 1 demodulated by the demodulation circuit 105
01 is input. Then, the first modulation circuit switching means 102 and the second modulation circuit switching means 102 receive the switching signal from the signal processing device 101.
Modulation circuit switching means 103 is switched, and the first to n-th
A modulation circuit having an optimum transmission rate is selected from among the modulation circuits 10-1 to 10-n, and the data is transmitted to the radio 104,
It is transmitted via the antenna 106.

[0008]

However, in a wireless communication system in which the amount of transmission data changes as described above,
No consideration is given to the effect on other peripheral equipment. Specifically, in the TDMA system shown in FIG. 9, the transmission power is turned on and off instantaneously (burst-like), so that the electric field strength largely changes in a short time near the transmitter.

FIG. 11 shows a simple configuration of another device arranged near a transmitter having the TDMA system. In FIG. 11, reference numeral 110 denotes an antenna, and 111 denotes a parasitic diode. In FIG. 11, an electric field that has changed greatly in a short time is received by an antenna 110, and is subjected to AM detection by an internal parasitic diode 111. The detected signal not only interferes with a signal originally required by the device, but also causes a malfunction of the device.

On the other hand, in the CDMA system, the energy amount after despreading at the receiver side (Eb (energy amount per bit) / I0 (energy amount per 1 Hz)) is kept constant. Changes the diffusivity. For example, when the transmission rate is quadrupled, the spreading factor is reduced to 1/4 and the transmission power is also quadrupled for transmission. At this time, on / off control of transmission power as in the TDMA method is not performed. However, when transmitting audio data, when there is no sound or when packet data is not transmitted, the transmission power is temporarily turned off. Then, when returning to the normal transmission state again, since the transmission power is controlled to be turned on in a burst like the TDMA system, the same problem as in the above-described TDMA system may occur.

In the radio communication method of FIG. 10 in which the transmission rate is changed, a plurality of modulation circuits corresponding to each transmission rate are prepared in advance, and a modulation circuit having an optimum transmission rate for the demodulated signal is provided. Is just selecting one,
No consideration is given to the effect of the change in the electric field by the wireless device on other devices arranged near the device.

[0012] As described above, a device placed around a communication device having a wireless communication system in which the amount of transmitted data changes is a device with low power consumption, a device with low impedance of a circuit, a shield shielding device, or the like. EMI (Electrom
However, there is a problem in that the antenna is directly affected by an electromagnetic interference (electromagnetic interference).

Therefore, the present invention has been made to solve the problems of the related art, and an object of the present invention is to change the transmission rate stepwise according to the amount of data to be transmitted. It is an object of the present invention to provide an optimal transmitting device that suppresses a sharp change in the electric field intensity and reduces the influence of EMI on other devices placed in the vicinity.

[0014]

According to the present invention, there is provided a transmitting apparatus comprising a storage means for storing input data, and a modulation means for modulating and transmitting transmission data read from the storage means. A transmission apparatus comprising: means for calculating the remaining data amount of the storage means; and speed control means for variably controlling the speed of the data read from the storage means in accordance with the remaining data amount. .

Further, the apparatus further comprises an amplifying means for amplifying and controlling the output of the modulating means in accordance with the speed.

Further, if the remaining data amount is larger than the data amount calculated by multiplying the data amount of the read data by a predetermined coefficient, the speed control means increases the speed by a predetermined amount. If the remaining data amount is smaller than the data amount calculated by multiplying the data amount of the read data by the predetermined coefficient, the speed is reduced by a predetermined amount.

[0017] The present invention is further characterized by further comprising an insertion means for inserting the information indicating the speed into the read data and transmitting the information.

The operation of the present invention will be described. The remaining data amount obtained by subtracting the speed-converted and transmitted data amount from the input data amount is compared with the speed-converted and transmitted data amount. Judge whether to increase or decrease the rate. The speed of the transmission data is converted based on the data rate obtained as a result of this determination. Further, the degree of amplification is set according to the data rate. As a result, the transmission data is transmitted in stages, so that the change in the electric field strength is suppressed to a small value.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a transmission device according to an embodiment of the present invention. Referring to FIG. 1, a transmitting apparatus according to the present invention includes a write counter 11, a read counter 12, a RAM (Ra)
An FIFO (First In First Out) data buffer 10 that has an Ndam Access Memory 13 and a remaining amount calculation unit 14 and temporarily stores input data, a data rate determination unit 15, and a data rate generation unit 16 Multiplexing unit 17 and speed conversion unit 1
8, a modulating unit 19 and an amplifying unit 20.

Next, the operation of the transmitting apparatus shown in FIG. 1 will be described. When data is input to the FIFO data buffer 10, the write counter 11 specifies a write address for the RAM 13 according to the write enable. Also,
The write counter 11 sends the data amount input to the FIFO data buffer 10 to the remaining amount calculation unit 14. Further, the read counter 12 designates a read address to the RAM 13 based on the read enable signal input from the multiplexing unit 17, recognizes the total data amount already transmitted by the speed conversion unit 18, and outputs it to the remaining amount calculation unit 14. I do.

The remaining amount calculation unit 14 subtracts the total amount of data already transmitted from the amount of data input to the FIFO data buffer 10 to calculate the amount of remaining data currently remaining in the FIFO data buffer 10, and calculates the amount of remaining data. Is output to the data rate determination unit 15. Data rate determination unit 15
Can be transmitted by the FIFO data buffer 10, which is calculated by multiplying the currently transmitted data amount obtained from the product of the current data rate notified by the data rate generation unit 16 and the burst time by a predetermined coefficient. Calculate the total data volume. Here, an algorithm performed by the data rate determination unit 15 will be described with reference to FIG.

FIG. 2 shows an example of an algorithm when the data rate judgment section 15 judges the data rate. In FIG. 2, a1, a2, a3, a4,.
n is the data amount per unit time (one burst time). Here, it is assumed that an-1 / an = α, and when α = １ ／, the data amount a1, a2, a3, a4,... An per unit time (one burst time) increases, and α = 2, data amount a1, a2, a3, a4,... Per unit time (one burst time)
an has a decreasing relationship.

Further, the total of the data amount per unit time (one burst time) is obtained, and a1 + a2 + a3 + a4 +... + An-1 + an = 1 + 1
... + 1 / ＋ １2 = β. Here, β is a coefficient indicating the total data amount that can be transmitted by the FIFO data buffer 10 until the transmission data of the FIFO data buffer 10 is exhausted at the data rate currently being transmitted.

At this time, the data rate determination unit 15 shown in FIG.
Is ｛(current data rate) * (one burst time)｝ * β
≧ Remaining data amount That is, if the total data amount that can be transmitted at the current data rate is larger than the remaining data amount, it is determined to lower the data rate, and {(current data rate) * (one burst time)} * β
<Remaining data amount That is, if the total data amount that can be transmitted at the current data rate is smaller than the remaining data amount, it is determined to increase the data rate.

Returning to FIG. 1, upon receiving the result of the determination by the data rate determining section 15, the data rate generating section 16 generates the next data rate information, and transmits this information to the data rate determining section 1.
5, and notifies the multiplexing unit 17, the speed conversion unit 18, and the amplification unit 20, respectively. The data rate determination unit 15 determines the next increase or decrease of the data rate based on this information.

The speed conversion unit 18 sequentially reads out the transmission data sent from the multiplexing unit 17 at a data rate according to the data rate information. The read data is further subjected to a predetermined modulation by the modulation unit 19 and sent to the amplification unit 20.

The multiplexing unit 17 includes a data rate generation unit 16
Readout counter 12 based on the data rate information obtained from
And outputs a read enable signal for calculating the total amount of data sent to the speed conversion unit. The multiplexing unit 17 adds a unique word (UW) to the data transmitted from the FIFO data buffer 10 and a rate instruction bit for notifying the rate increase / decrease obtained from the data rate determining unit 15, To send to.

Further, the amplification unit 20 changes the amplification degree according to the data rate information obtained from the data rate generation unit 16. When the data reading speed changes in the speed conversion unit 18, the output energy (transmission power) per predetermined time also changes. Therefore, the amplification degree of the modulation signal is controlled to keep the transmission power per bit constant.

FIG. 3 schematically shows a signal output from the amplifying unit 20 after the modulated signal passed through the modulating unit 19 is amplified with an amplification factor corresponding to a change in the data rate. In FIG. 3, before and after the data 32 transmitted from the FIFO data buffer 10, the multiplexing unit 17
W31 and rate instruction bit 33 are respectively added.

FIG. 4 shows a data flow in each block of the present apparatus. In FIG. 4A, first, when 1000-bit data is input to the FIFO data buffer 10 from a state where no data is transmitted, as shown in FIG. 0 bit to 1
000 bits.

The data rate determination section 15 determines whether to increase or decrease the data rate based on the above equation. In this case, as shown in FIG. 4C, since the total data amount that can be transmitted at the current data rate is 0, the remaining data amount is larger, and the data rate determination unit 15 increases the data rate. To the effect. The data rate generation unit 16 determines the data rate from the result of the determination as the minimum value of 10 kbp.
Data rate information to be set to s is generated, and the fact is notified to the speed conversion unit 18. The speed conversion unit 18 reads the data transmitted from the multiplexing unit 17 at a data rate of 10 kbps, as shown in FIG. And
As shown in FIG. 4E, the modulation section 19 performs predetermined modulation.

Next, the currently transmitted data amount is such that the data rate is 10 kbps and one burst time is 10 ms.
Therefore, it becomes 100 bits. Therefore, the remaining data amount of the remaining amount calculation unit 14 is 900 bits. Even in this case, the determination by the data rate determination unit 15 does not change, so that the data rate is set to 20 kbps, which is twice as high. Thereafter, the data rate is set for each burst time (10 ms) in the same procedure, and when the data rate is reduced, the data rate is set to 倍 of the current data rate.

However, when decreasing the data rate,
Since the rate of change is invariable to 1/2 times, F
When there is no data input to the IFO data buffer 10, the remaining data amount becomes insufficient or the remaining data amount becomes zero with respect to the data amount that can be transmitted at the set data rate.
Therefore, there is a case where there is no data to be transmitted.

In this case, if the data rate is set to 0 at that moment, the amount of data to be transmitted instantaneously changes greatly, which affects other devices as described later. Therefore, in this case, the multiplexing unit 17
Sends a notification to the effect that the remaining data amount is insufficient
, Redundant data is added to transmission data. As a result, the rate of change of the data rate is kept constant.

As a result, the total data amount actually transmitted is equal to or slightly larger than the total data amount input to the FIFO data buffer 10. In the case of FIG. 4, the redundant data is 20 for the total data amount of 3000 bits of the input data.
0 bits are added and the total amount of data actually transmitted is 32
It is slightly increased to 00 bit bits.

FIG. 5 shows an example of a receiving apparatus opposed to the transmitting apparatus of the present invention. Reference numeral 51 denotes a demodulation unit, and 52 denotes a rate instruction detection unit. In the receiving apparatus of FIG. 5, when transmission starts from a state where no data is transmitted from the transmitting apparatus, the transmitting apparatus determines in advance that data is transmitted at the minimum data rate. The device waits for the UW and the received data at the minimum data rate.

After the UW and the received data are received at the minimum data rate, information on the increase or decrease of the data rate received next is added to the rate indication bit in the data received at the minimum data rate. This is detected by the rate instruction detecting unit 52, and the detection result is demodulated by the demodulating unit 5.
Notify 1. The demodulation unit 51 changes the reception data rate based on the notification and demodulates the reception data.

FIG. 6 shows a configuration of the transmitting apparatus according to the present invention, a receiving apparatus facing the transmitting apparatus, and other devices placed near these apparatuses. In FIG. 6, reference numeral 61 denotes a transmitting apparatus having the configuration shown in FIG.
Reference numeral 63 denotes a receiving device having the configuration shown in FIG.

FIG. 7 schematically shows a change in the differential amount of a signal obtained by AM detection of data transmitted by the transmission apparatus of the present invention by a parasitic diode in another device 62 in FIG. is there. In the conventional transmitting device, FIG.
Since the amount of data changed instantaneously as in
The differential waveform of the M detection signal also had a steep impulse property. However, according to the transmitting apparatus of the present invention, since the data rate changes stepwise, the change in the data amount per predetermined time becomes small as shown in FIG. Therefore, the peak value of the differential waveform of the AM detection signal is also reduced, and the influence on other devices is reduced.

FIG. 8 shows, in a spectrum, the influence of the fluctuation of the electric field of the transmitting device 61 on the frequency band used by the other device 62 in FIG. Other devices 62
Is 100 Hz to 400 Hz, the spectrum of the other device 62 due to the AM detection signal (interference wave) is smaller in the case of the present invention shown by the dotted line than in the conventional case shown by the solid line. ing. As a result, it can be seen that there is an effect of improving an interference wave level in a band used by another device and preventing malfunction of the device.

It is apparent that the present invention is not limited to the above-described embodiment, but can be appropriately changed within the scope of the technical idea of the present invention. For example, in the above-described embodiment, the coefficient for changing the data rate to twice or half the current data rate is described as being limited to α = 2 or α = １ ／. It is clear that the value of α is not limited to this, and the rate of change of the data rate can be set arbitrarily.

[0042]

As described above, according to the present invention, the amount of data that has been speed-converted and transmitted is compared with the remaining amount of input data, and the data rate is sequentially increased or decreased in accordance with the comparison result. Then, transmission data speed conversion is performed.
Further, the amplification degree is changed according to the change of the data rate. Therefore, even in a wireless communication system such as the TDMA system in which the transmission power is periodically turned on and off and the amount of transmission data greatly changes instantaneously, the amount of change in the electric field strength can be reduced. This makes it possible to reduce the effect of EMI on other devices located near the communication device.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmission device of the present invention.

FIG. 2 is a diagram illustrating an algorithm of a data rate determination unit according to the present invention.

FIG. 3 is a schematic diagram of transmission data output from an amplification unit according to the present invention.

FIG. 4 is a diagram showing a data flow in each block of the present invention.

FIG. 5 is a schematic diagram of a receiving device facing the transmitting device of the present invention.

FIG. 6 is a system configuration diagram including a transmission device and a reception device of the present invention.

FIG. 7 is a schematic diagram of a waveform of transmission data and a waveform detected by AM in another device.

FIG. 8 is a diagram illustrating a spectrum of an interference wave in a frequency band of another device.

FIG. 9 is a diagram showing ON / OFF of transmission power in a TDMA system.

FIG. 10 is a configuration diagram of a data communication method with a variable transmission speed.

FIG. 11 is a configuration diagram of another device.

[Explanation of symbols]

 Reference Signs List 10 FIFO data buffer 11 Write counter 12 Read counter 13 RAM 14 Remaining amount calculation unit 15 Data rate judgment unit 16 Data rate generation unit 17 Multiplexing unit 18 Speed conversion unit 19 Modulation unit 20 Amplification unit

Continued on the front page F term (reference) 5C025 AA01 5K034 AA05 DD02 EE03 HH01 HH21 5K047 BB01 CC02 LL01 MM02 MM03 MM56 5K060 BB07 FF09 HH01 HH39 JJ23 LL02

Claims (4)

[Claims] 1. A transmitting apparatus comprising: a storage unit for storing input data; and a modulation unit for modulating and transmitting transmission data read from the storage unit, wherein a remaining data amount of the storage unit is calculated. And a speed control means for variably controlling the speed of the data read from the storage means in accordance with the remaining data amount. 2. The transmitting apparatus according to claim 1, further comprising an amplifying means for amplifying and controlling an output of said modulating means according to said speed. 3. The speed control means increases the speed by a predetermined amount if the remaining data amount is larger than a data amount calculated by multiplying a data amount of the read data by a predetermined coefficient. And if the remaining data amount is smaller than a data amount calculated by multiplying the data amount of the read data by the predetermined coefficient, the speed is reduced by a predetermined amount. 2. The transmitting device according to 2. 4. The transmission device according to claim 1, further comprising an insertion unit that inserts the information indicating the speed into the read data and transmits the information.