Radio data communication equipment

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a wireless data communication device that is used as a premises data communication system using a wireless LAN to reduce current consumption during standby for transmission and reception of packet data.

【0002】

[Conventional technology]

Conventionally, as a premises data communication system, a wireless LAN that transmits data with a specific low power in the 400 MHz band and 1.2 GHz band is known, but a wireless LAN that transmits data with a specific low power in the 2.4 GHz band, which has a higher frequency. Is beginning to be used. When data is transmitted using such a wireless LAN, a modem powered by a battery is used in a notebook personal computer or a mobile terminal. Therefore, this modem needs to reduce the current consumption during standby for data transmission and data reception so that it can be used for a longer period of time.

【0003】

FIG. 4 is a block diagram showing a schematic configuration of a wireless LAN modem that employs a direct sequence spread spectrum (DSSS) method for power saving. In FIG. 4, this example has an antenna 1 for transmission / reception, a spread spectrum transmitter / receiver 2, and a media access control (MAC) processing unit 3.

【0004】

FIG. 5 is a block diagram showing a detailed configuration of the spread spectrum transmitter / receiver shown in FIG. In FIG. 5, the spread spectrum transmitter / receiver 2 has a transmission digital processing unit 10 that spreads and transmits transmission data Std, a reception digital processing unit 20 that outputs demodulated reception data Srd, and orthogonal modulation that performs orthogonal modulation. The level of the IF signal from the device 30, the IF (intermediate frequency) section 40 that performs frequency conversion, the RF (high frequency) section 50 that transmits transmission power and amplifies the received signal, and the mixer 42 of the IF section 40. A level detector 60 is provided to detect the above.

【0005】

Further, a level comparator 70 is provided to compare the reception level detected by the level detector 60 with the threshold value VE. Further, when the reception level does not exceed the threshold value VE in the level comparator 70, the supply of the clock signal to the transmission digital processing unit 10 and the reception digital processing unit 20 is stopped, and the reception level sets the threshold value VE. It has a clock generation control unit 90 that controls to start supplying a clock signal when the value is exceeded. Further, a clock oscillator (clock generator) 100 that supplies a clock signal to the transmission digital processing unit 10, the reception digital processing unit 20, and the like and stops the supply under the control of the clock generation control unit 90, and an antenna 200 for transmission and reception. It is roughly composed of and.

【0006】

The transmission digital processing unit 10 in FIG. 5 uses a data modulator 11 that modulates the transmission data Std, a diffusion encoder 12 that encodes the modulation data from the data modulator 11, and a code from the diffusion encoder 12. It has a spectrum diffuser 13 that diffuses the spectrum.

【0007】

Further, the receiving digital processing unit 20 includes an A / D converter 21 that digitizes the signal from the orthogonal modulator 30, a correlator 22 that performs despreading processing, and a data demodulator 23 that demodulates data from the despreading signal. And have.

【0008】

Further, the IF (intermediate frequency) unit 40 obtains a predetermined transmission frequency and outputs a signal from a VCO (voltage control oscillator) 43 for converting a reception frequency into an IF signal and a signal from the orthogonal modulator 30. A mixer 41 for generating and transmitting a transmission signal (high frequency signal) having a predetermined frequency, and a mixer 42 for converting a signal received from the RF unit 50 into an IF signal with a predetermined frequency and outputting the signal are provided.

【0009】

Further, the RF (radio frequency) unit 50 includes a transmission amplifier 51 that generates and transmits a transmission signal from the IF unit 40 to a predetermined power, a reception amplifier 52 that amplifies and outputs a reception signal from the antenna 200, and a transmission amplifier. A transmission / reception switch 53 is provided, which selects the transmission power from 51 and sends it to the antenna 200, or switches the reception signal from the antenna 200 to the reception amplifier 52 by the transmission / reception switching signal.

【0010】

Next, the operation of this conventional example will be described. When transmission data is generated, a clock signal is supplied from the clock oscillator 100 to the transmission digital processing unit 10 by a transmission start signal from a CPU or the like (not shown) to operate, and the data modulator 11 operates as a spread encoder 12 and a spectrum spreader. The spectrum is diffused by 13. This spectral diffusion signal is orthogonally modulated by the orthogonal modulator 30, mixed with the oscillation signal from the VCO (voltage controlled oscillator) 43 by the mixer 41, frequency-converted, and then amplified to a predetermined power by the transmission amplifier 51. This high frequency power is transmitted through the antenna 200.

【0011】

On the other hand, at the time of reception, after the reception signal (high frequency signal) from the antenna 200 is amplified by the reception amplifier 52, it is mixed with the oscillation signal (local oscillation signal) from the VCO (voltage controlled oscillator) 43 by the mixer 42 to achieve an intermediate frequency. Converted to (IF) signal. This IF signal is quadrature modulated by the quadrature modulator 30 and converted into a digital signal by the A / D converter 21. Further, it is back-diffused by the correlator 22 and demodulated to the original data by the data demodulator 23.

【0012】

In such an operation, power saving is achieved during data reception and standby for data transmission, and a clock signal to the transmission digital processing unit 10 and the reception digital processing unit 20 is achieved except during data transmission and data reception. Supply has been stopped and its processing operation has stopped. At the time of standby in this case, the IF unit 40 and the RF unit 50 are operating, and the IF signal from the mixer 42 of the IF unit 40 is input to the level detector 60, and the level of the IF signal is detected here. For example, the level is detected by envelope detection. This level signal is input to the level comparator 70 and compared with the threshold VE.

【0013】

In this comparison, when the reception level (IF signal) does not exceed the threshold value VE, that is, when there is no reception data, the clock generation control unit 90 controls the transmission digital processing unit 10 and the reception digital processing unit 20 from the clock oscillator 100. Controls the supply stop of the clock signal to.

【0014】

Further, when the reception level (IF signal) exceeds the threshold value VE, that is, when data is received, the clock generation control unit 90 sends the transmission digital processing unit 10 from the clock oscillator 100 to the reception digital processing unit 20. Controls to start supplying the clock signal. The supply of this clock signal sets the initial synchronization mode operating state.

【0015】

In this way, even with the conventional wireless data communication device, the supply of the clock signal to the transmission digital processing unit 10 and the reception digital processing unit 20 is stopped at the time of standby other than data transmission and data reception, and the power saving is achieved. Has been done.

【0016】

As a communication device for such power saving, a power control method for a wireless device disclosed in Japanese Patent Application Laid-Open No. 1-280931 is known. In this example of publication, power is supplied from the power source to the receiving unit at regular intervals during standby. Further, in the mobile communication system disclosed in Japanese Patent Application Laid-Open No. 4-196833, when the wireless call receiver receives a call to its own terminal, the power of the automobile telephone is turned on. In this way, power saving is achieved even in the conventional wireless data communication device.

【0017】

[Problems to be Solved by the Invention]

However, in the wireless data communication device of the above-mentioned conventional example, the incoming packet other than the packet addressed to the own station is received and this packet is passed to the media access control (MAC) as in the wired LAN, so that the power consumption is saved. Even the wireless data communication device shown in FIG. 5, which has been improved, has a drawback that the power consumption increases as the amount of traffic increases.

【0018】

Further, in the examples shown in JP-A No. 1-280931 and JP-A-4-196833, it is not possible to cope with the increase in power consumption due to the increase in the amount of traffic in packet transmission.

【0019】

The present invention solves such a drawback in the conventional technique, reduces the current consumption during standby for transmission and reception of packet data, and enables effective power saving. The purpose is to provide.

【0020】

[Means for solving problems]

In order to achieve the above object, the wireless data communication device according to claim 1 discriminates between a receiving means that receives wirelessly and demotes and receives a packet and whether or not the reception by the receiving means is a broadcast packet. The first identification means to identify the packet, the second identification means to identify whether the packet is addressed to the own terminal when the first identification means is not a broadcast packet, and the second identification means to identify the packet addressed to the own terminal. When it is identified that it is not, the configuration is provided with a stop means for stopping the operation of the demodulation processing system in the subsequent receiving means.

【0021】

The wireless data communication device according to claim 2 is provided with data length detecting means for detecting the data length in a packet, and when the stopping means identifies that the second identifying means is not a packet addressed to its own terminal. In order to stop the operation of the demodulation processing system in the receiving means during the period determined by the data length and the transmission speed detected by the data length detecting means, the supply of the clock signal to the demodulation processing system in the receiving means is stopped. ..

【0022】

The wireless data communication device according to claim 3 cannot detect the start delimiter inserted in the header of the packet after the stop means establishes the initial synchronization for supplying the clock signal, and the terminal to which the packet is addressed. When the identifier indicating the above cannot be detected, variable length data is detected, and when this detection is completed, the packet forced termination signal is sent to the demodulation processing system in the receiving means in order to stop the operation of the demographic processing system. It is configured to stop the signal supply.

【0023】

The wireless data communication device according to claim 4 is provided with a transmitting means that at least modulates the data and spreads the spectrum to wirelessly transmit the packet, and the stopping means stops the operation of the demodulation processing system in the receiving means. At that time, in order to stop the operation of the transmitting means, the supply of the clock signal to the transmitting means is stopped.

【0024】

The wireless data communication device according to claim 5 is provided with a transmitting means that at least modulates the data and spreads the spectrum to wirelessly transmit the packet, and the stopping means stops the operation of the demodulation processing system in the receiving means. At that time, in order to stop the operation of the transmitting means, the supply of the clock signal to the transmitting means is stopped, and the clock signal to the transmitting means is started in order to start the operation of the transmitting means when the transmission data is generated. It is configured to supply.

【0025】

The wireless data communication device according to claim 6 cannot detect the start delimiter inserted in the header of the packet after the stop means establishes the initial synchronization for supplying the clock signal, and the terminal to which the packet is addressed. When the identifier indicating the above cannot be detected, variable length data is detected, and when this detection is completed, the data modulation and spread spectrum of the transmission means are performed in order to perform the data modulation of the transmission means and the operation of the spread spectrum processing system. The configuration is such that the supply of the clock signal to the processing system is stopped.

【0026】

[Action]

When the wireless data communication device having the configuration according to claims 1, 2 and 3 is identified as not a packet addressed to its own terminal, the operation of the demodulation processing system in the receiving means is stopped during a period determined by the data length and the transmission speed. It is carried out. In this case, after the initial synchronization that supplies the clock signal is established, if the start delimiter inserted in the header of the packet cannot be detected and the identifier indicating the destination terminal of the packet cannot be detected, the variable length data. When the detection is completed, the supply of the clock signal to the demodulation processing system in the receiving means is stopped in order to stop the operation of the demodulation processing system in the receiving means.

【0027】

Therefore, when the packet is not addressed to the own terminal, the subsequent packet receiving operation can be forcibly stopped, and the power consumption when the traffic amount addressed to the own station increases is reduced. That is, the current consumption during standby for receiving packet data is reduced.

【0028】

The wireless data communication device having the configuration according to claims 4, 5, and 6 supplies a clock signal to the transmitting means in order to stop the operation of the transmitting means when the operation of the demodulation processing system in the receiving means is stopped. Is stopped, and a clock signal is supplied to the transmitting means in order to start the operation of the transmitting means when transmission data (transmission event) occurs. In this case, variable length data cannot be detected after the initial synchronization that supplies the clock signal is established, and the start delimiter inserted in the header of the packet cannot be detected, and the identifier indicating the destination terminal of the packet cannot be detected. When the detection is completed, the data modulation of the transmission means and the supply of the clock signal to the spread spectrum processing system are stopped in order to stop the operation of the data modulation and the spread spectrum processing system of the transmission means.

【0029】

Therefore, the transmission operation can be forcibly stopped at the time of standby at the time of reception in the configurations according to claims 1 to 3, and the current consumption is reduced even at the time of standby at the time of receiving and transmitting packet data.

【0030】

[Example]

Next, an embodiment of the wireless data communication device of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in FIG. 5 above are designated by the same reference numerals, and the duplicate detailed description of these components will be omitted.

【0031】

FIG. 1 is a block diagram showing a configuration of an embodiment of the wireless data communication device of the present invention. In FIG. 1, this wireless data communication device is a spread spectrum transmitter / receiver 2 in a wireless LAN modem that employs the direct sequence spread spectrum (DSSS) method shown in FIG. That is, it is configured together with the transmission / reception antenna 1 and the media access control (MAC) processing unit 3 in FIG.

【0032】

The spread spectrum transmitter / receiver 2 in this embodiment has a transmission digital processing unit 10, a reception digital processing unit 20, an orthogonal modulator 30, an IF (intermediate frequency) unit 40, an RF (high frequency) unit 50, and the same as in FIG. It has a level detector 60, a level comparator 70, a clock generation control unit 90, a clock oscillator 100, and an antenna 200 for transmission / reception.

【0033】

Further, in the spread spectrum transmitter / receiver 2 in this embodiment, a controller 80 is newly provided between the level comparator 70 and the clock generation control unit 90.

【0034】

Further, the transmission digital processing unit 10 has a data modulator 11, a diffusion encoder 12, and a spectrum spreader 13 as in the previous FIG. 5, and the reception digital processing unit 20 also has an A / D converter 21 and a correlator 22. It also has a data demodulator 23. Further, the IF (intermediate frequency) unit 40 also has a VCO (voltage controlled oscillator) 43 and mixers 41, 42, and the RF (radio frequency) unit 50 also has a transmission amplifier 51, a reception amplifier 52, and a transmission / reception switch 53. There is.

【0035】

FIG. 2 is a diagram showing a configuration of packets transmitted by the spread spectrum transmitter / receiver of this embodiment. In FIG. 2, this packet has a header (H1) 1 into which a preamble signal and a start delimiter are inserted, an identifier (H2) 2 which is a header for MAC and indicates that the packet is a broadcast packet, and a packet. It has an identifier (STID) 3 indicating the destination terminal and variable length data (L) 4.

【0036】

Next, the operation of this embodiment will be described. When transmission data is generated, a clock signal is supplied from the clock oscillator 100 to the transmission digital processing unit 10 by a transmission start signal from a CPU or the like (not shown) to operate, and the data modulator 11 operates as a spreading encoder 12 and spectrum spreading. The spectrum is diffused by the vessel 13. This spectral diffusion signal is orthogonally modulated by the orthogonal modulator 30, mixed with the oscillation signal from the VCO (voltage controlled oscillator) 43 by the mixer 41, frequency-converted, and then amplified to a predetermined power by the transmission amplifier 51. This high frequency power is transmitted through the antenna 200.

【0037】

On the other hand, at the time of reception, after the reception signal (high frequency signal) from the antenna 200 is amplified by the reception amplifier 52, it is mixed with the oscillation signal (local oscillation signal) from the VCO (voltage controlled oscillator) 43 by the mixer 42 to achieve an intermediate frequency. Converted to (IF) signal. This IF signal is quadrature modulated by the quadrature modulator 30 and converted into a digital signal by the A / D converter 21. Further, it is back-diffused by the correlator 22 and further demodulated to the original data by the data demodulator 23.

【0038】

In such an operation, it is possible to save power during data reception and standby for data transmission, and clock signals to the transmission digital processing unit 10 and the reception digital processing unit 20 other than during data transmission and data reception. Supply is stopped. First, the IF signal from the mixer 42 of the IF unit 40 is input to the level detector 60, and the level of the IF signal is detected here. For example, the carrier level is detected by envelope detection.

【0039】

This level signal is input to the level comparator 70 and compared with the threshold value VE. If the reception level (IF signal) does not exceed the threshold value VE in this comparison, that is, if there is no reception data, the controller 80 controls the clock oscillator 100 through the clock generation control unit 90 to the reception digital processing unit 20. The supply of the clock signal of is stopped. That is, the standby mode is set.

【0040】

FIG. 3 is a flowchart showing a processing procedure of the operation at the time of data reception. In FIG. 3, the IF signal from the mixer 42 of the IF unit 40 is input to the level detector 60 in the standby mode other than the time of data transmission and the time of data reception, and the level of the IF signal is detected here. For example, the carrier level is detected by envelope detection. This level signal is input to the level comparator 70 and compared with the threshold value VE (steps S10 and S11).

【0041】

If carrier detection cannot be performed in step S11 (step S11: No), the process returns to step S10 to process this carrier detection wait. If carrier detection is possible in step S11, that is, when a packet is received (step S11: Yes), this detection signal is input to the controller 80, and the controller 80 starts clocking at the clock generation control unit 90. Send a signal. The clock generation control unit 90 controls the clock oscillator 100 by the clock start signal to supply the clock signal to the reception digital processing unit 20. That is, the initial synchronization mode is set.

【0042】

After this initial synchronization is established, the data demodulation unit 23 detects the start delimiter inserted in the header (H1) 1 shown in FIG. 2 (step S12). If the start delimiter can be detected (step S12: Yes), the received MAC frame transmission is transferred from the spread spectrum transmitter / receiver 2 shown in FIG. 4 to the MAC processing unit 3 (step S13). The MAC processing unit 3 determines whether or not the frame that started reception is a broadcast packet (step S14).

【0043】

Whether or not the packet is a broadcast packet is determined by detecting the identifier (H2) 2 indicating that the packet in the header for MAC is a broadcast packet. If this identifier (H2) 2 can be detected (step S14: Yes), normal packet reception processing is performed (step S15). If the identifier (H2) 2 cannot be detected (step S14: No), the identifier (STID) 3 in which the packet in the header for MAC shown in FIG. 2 indicates the destination terminal is detected (step S16).

【0044】

If the identifier (STID) 3 can be detected (step S16: Yes), the normal packet reception process in step S15 is performed. If the identifier (STID) 3 cannot be detected (step S16: No), the variable length data (L) 4 shown in FIG. 2 is detected (step S17).

【0045】

When the detection of the variable length data (L) 4 is completed, the MAC processing unit 3 sends a packet forced termination signal to the controller 80 in the spread spectrum transmitter / receiver 2. The controller 80 stops the supply of the clock signal to the reception digital processing unit 20 to the clock generation control unit 90, and is set to the packet forced termination mode (step S18).

【0046】

Further, the MAC processing unit 3 disables the packet forced termination signal after the variable length data (L) 4 and the time (period) determined by the current reception transmission speed have expired. With this disable, the spread spectrum transmitter / receiver 2 shifts to the original standby mode.

【0047】

As described above, in this embodiment, only the header for the packet addressed to the other terminal is received, and the data portion occupying most of the frame stops the supply of the clock signal to the processing unit. Therefore, the power consumption is reduced even when the amount of traffic to other terminals other than the own terminal is large.

【0048】

In addition, there is no need to perform a protocol handshake as in power management in MAC processing. That is, there is an advantage that the system throughput does not decrease due to the overhead of the protocol handshake.

【0049】

[Effect of the invention]

As is clear from the above description, according to the wireless data communication device according to claims 1, 2 and 3, the receiving means in the receiving means during a period determined by the data length and the transmission speed when it is identified that the packet is not addressed to the own terminal. Since the operation of the demodulation processing system is stopped, the subsequent packet reception operation can be forcibly stopped when the packet is not addressed to the own terminal, and the power consumption when the traffic amount addressed to the own station increases is reduced. To. That is, it has the effect of reducing the current consumption during standby for receiving packet data.

【0050】

According to the wireless data communication device according to claims 4, 5, and 6, when the operation of the demodulation processing system in the receiving means is stopped, the clock signal is supplied to the transmitting means in order to stop the operation of the transmitting means. At the time of reception in the configuration according to claims 1 to 3, since the clock signal is supplied to the transmission means in order to stop and start the operation of the transmission means when the transmission data (transmission event) occurs. The transmission operation can be forcibly stopped at the time of standby, and the current consumption can be reduced even during standby at the time of receiving and transmitting packet data.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the structure of the Example of the wireless data communication apparatus of this invention.

[Figure 2]

It is a figure which shows the structure of the packet transmitted by the spread spectrum transmitter / receiver in the Example.

[Fig. 3]

It is a flowchart which shows the processing procedure of the operation at the time of data reception in an Example.

[Fig. 4]

It is a block diagram which shows the schematic structure of the wireless LAN modem which adopts the DSSS system.

[Fig. 5]

It is a block diagram which shows the detailed structure of the spread spectrum transmitter / receiver shown in FIG.

[Explanation of symbols]

2 Spread spectrum transmitter / receiver 3 MAC processing unit 10 Transmission digital processing unit 11 Data modulator 12 Diffusion encoder 13 Spectral diffuser 20 Received digital processing unit 22 Correlator 23 Data demodulator 30 Quadrature modulator 40 IF section 50 RF section 60 level detector 70 level comparator 80 controller 90 Clock generation control unit 100 clock oscillator