JP2006067089A - Transceiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transceiver capable of reducing power required for reception, and also, capable of preventing the occurrence of collision of transmission and delay of reception. <P>SOLUTION: A conversion means 101 demodulates a packet and converts it to a bit string. A normality determining means 102 determines whether the packet is normal or not by first information in the bit string. A means 103 for determining that a packet is addressed to its own station determines whether the packet is addressed to its own station or not by second information in the bit string. A stop time calculating means 104 calculates a transmission stop time by stop information in the bit string. A restart time calculating means 105 calculates a reception restart time by restart information in the bit string. When it is determined that the packet is normal and not addressed to its own station, a stop means 107 interrupts the reception by acquiring the transmission stop time and the reception restart time, and stops a part or all of the transceiver. A restarting-up means 108 starts up again a part or all of the transceiver stopped on the basis of the transmission stop time, the reception restart time, and the transmission request of the transceiver. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmission / reception device when wireless communication is performed with three or more devices, and more particularly to a transmission / reception device that achieves low power consumption during reception.

  When communication is performed between three or more transmission / reception apparatuses, the received packet may not be addressed to the own station. Since it is not necessary to demodulate all of the packets that are not addressed to the own station, the power required for reception can be reduced by interrupting demodulation in the middle of reception and stopping part or all of the transmission / reception apparatus.

Some conventional transmission / reception devices analyze destination information included in a packet, stop reception when the packet is not addressed to the own station, and stop a part of the transmission / reception device (for example, Patent Document 1). reference).
JP-A-8-181702

However, depending on the communication system, the time at which transmission must be stopped and the time at which reception must be resumed are defined, and these pieces of information are included in part of the packet as transmission stop information and reception restart information, respectively. There may be.
If the received packet is not addressed to the local station, the reception is interrupted after the destination information is demodulated in the prior art, and therefore transmission stop information and reception restart information may not be demodulated. If the transmission stop information is not demodulated, there is a problem in that this transmission / reception apparatus starts transmission during a period in which transmission is prohibited, and a collision with the transmission of another transmission / reception apparatus may occur. Also, if the reception resumption information is not demodulated, this packet may not be received because some or all of the transmission / reception apparatus is stopped even though there is a packet addressed to the own station, which may cause a delay in reception. There is a problem.

  In view of the problems in the prior art, the present invention provides a transmission / reception apparatus that reduces the power required for reception when receiving a packet that is not addressed to the local station, and that is less likely to cause transmission collision or reception delay. With the goal.

  The transmission / reception apparatus according to the present invention is a transmission / reception apparatus for transmitting / receiving a packet, based on conversion means for demodulating the packet and converting it into a bit string, and error detection information for detecting an error included in the bit string. Normality determining means for determining whether or not the packet is normal, and local station address determining means for determining whether or not the packet is addressed to the local station based on destination information included in the bit string A transmission stop time calculating means for calculating a transmission stop time based on the transmission stop information included in the bit string, and a reception restart time for calculating a reception restart time based on the reception restart information included in the bit string When it is determined that the packet is normal and the packet is not destined for the local station, the transmission stop time and the reception resumption time are acquired. Stop means for interrupting reception and stopping part or all of the transmission / reception device, based on the transmission stop time, the reception resumption time, and the transmission request of the transmission / reception device, part or all of the stopped transmission / reception device And restarting means for restarting.

  Further, according to the transmission / reception apparatus of the present invention, a transmission / reception apparatus for transmitting / receiving a packet, the conversion means for demodulating the packet and converting it into a bit string, and error detection information for detecting an error contained in the bit string Normality determination means for determining whether or not the packet is normal based on the address, and to the local station for determining whether or not the packet is addressed to the local station based on destination information included in the bit string Determining means; transmission stop time calculating means for calculating a transmission stop time based on the transmission stop information included in the bit string; and reception for calculating a reception restart time based on the reception restart information included in the bit string. A restart time calculating means, and when the packet is determined to be normal, the packet is determined not to be addressed to the own station, and the transmission stop time is smaller than a certain time. In addition, based on the transmission stop time, the reception resumption time, and the transmission request of the transmission / reception device, the stop means for acquiring the reception resumption time and suspending reception to stop part or all of the transmission / reception device, And restarting means for restarting part or all of the stopped transmission / reception apparatus.

  According to the transmission / reception apparatus of the present invention, when a packet that is not addressed to the local station is received, the power required for reception can be reduced, and transmission collisions and reception delays can be made difficult to occur.

Hereinafter, a transceiver according to an embodiment of the present invention will be described in detail with reference to the drawings.
First, an example of the configuration of a packet received by the transmission / reception apparatus of this embodiment will be described with reference to FIG. As shown in FIG. 6, the packet includes a PHY (Physical Layer) header 601, a MAC (Medium Access Control) header 602, and a data portion 603 in order from the top.
A known rule is defined in the PHY header 601, and the transmission / reception apparatus can determine whether the packet is normal based on this rule. However, this determination may be erroneous with a certain probability. Examples of known rules include parity bits and error detection codes.

The MAC header 602 includes control information, and includes, for example, destination information 6021, transmission stop information 6022, and reception resumption information 6023 as illustrated in FIG. However, the order of each information differs depending on the communication system. As shown in FIG. 6, destination information 6021 is arranged first, followed by transmission stop information 6022 and reception resumption information 6023, or in other cases. There is also. Each information may be divided into a plurality of pieces and arranged on the MAC header 602.
The transmission stop information 6022 is information used to calculate a transmission stop time that represents a time during which the transmission / reception apparatus must stop transmission. The transmission stop information 6022 may directly include the transmission stop time, or the transmission stop information 6022 does not directly include the transmission stop time, and the transmission stop information 6022 is based on a rule defined in advance by the communication system. Sometimes time is calculated. If the transmission stop time is fixedly set in advance, the MAC header may be set not to include the transmission stop information 6022. In this case, the transmission stop information demodulation process described below is skipped, and a fixed value is set as the transmission stop time.
The reception resumption information 6023 is information used to calculate a reception resumption time that represents a time during which the transmission / reception apparatus must resume reception. Similarly to the transmission stop information 6022, the reception resumption information 6023 may directly include the reception resumption time, or the reception resumption information 6023 does not directly include the reception resumption time. There is a case where the reception resumption time is calculated based on a rule defined in advance. If the reception resumption time is fixedly determined in advance, the MAC header may be set not to include the reception resumption information 6023. In this case, the demodulation process of the reception resumption information described below is skipped, and a fixed value is set as the reception resumption time.

  The data part 603 includes data transmitted from the transmission side to the reception side. Further, a known rule is defined in the data portion 603 as in the case of the PHY header, and it can be determined whether or not the packet is normal based on this rule. This rule may be the same as or different from the rule in the PHY header 601.

(First embodiment)
A transmitting / receiving apparatus according to a first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the transmission / reception apparatus 100 according to the present embodiment includes a demodulation unit 101, a packet normality determination unit 102, a local station determination unit 103, a transmission stop time calculation unit 104, a reception resume time calculation unit 105, a reception interruption. Unit 106, device stop unit 107, device restart unit 108, and restart determination unit 109.

  The demodulator 101 demodulates the received packet shown in FIG. In the present embodiment, the demodulator 101 demodulates only the PHY header 601, demodulates up to destination information 6021 included in the MAC header 602, demodulates up to transmission stop information 6022 included in the MAC header 602, The reception resumption information 6023 included in the MAC header 602 is demodulated.

The packet normality determination unit 102 determines whether the received packet is normal based on the demodulation result of the PHY header 601.
The own station address determining unit 103 determines whether the received packet is addressed to the own station based on the demodulation result up to the destination information 6021.
The transmission stop time calculation unit 104 calculates the transmission stop time based on the demodulation result of the transmission stop information 6022 included in the MAC header 602.
The reception restart time calculation unit 105 calculates the reception restart time based on the demodulation result of the reception restart information 6023 included in the MAC header 602.

  The reception interrupting unit 106 interrupts the transmission / reception apparatus 100 from receiving this packet when the packet normality determining unit 102 determines that the received packet is not normal. However, interrupting reception means stopping a series of processes performed in order to receive all packets being received. Further, when the reception is interrupted, the power of the transmission / reception device 100 is not turned off.

  The apparatus stopping unit 107 transmits when the packet normality determining unit 102 determines that the received packet is normal, and the own station address determining unit 103 determines that the received packet is not addressed to the own station. After all the bit strings corresponding to the stop information and the reception resumption information are output, the transmission / reception device 100 stops receiving this packet and stops a part or all of the transmission / reception device 100. However, stopping the transmission / reception device means an operation of changing the value of the current flowing through the transmission / reception device to a state where the current value becomes smaller or disappears than the value before the stop. Further, when only a part of the transmission / reception device 100 is stopped, it is desirable to preferentially stop a device with high power consumption, such as a power amplifier or an ADC (analog-to-digital converter). . Specifically, which part of the transmission / reception apparatus 100 is to be stopped will be described later with reference to FIG.

  The restart determination unit 109 measures an elapsed time from when transmission is stopped after waiting for a predetermined time after the transmission / reception apparatus 100 is stopped. Then, the restart determination unit 109 monitors whether the transmission / reception apparatus 100 has a transmission request, and when there is a transmission request, determines whether the measured elapsed time is longer than the transmission stop time, and is large. In this case, a request for restarting the apparatus is sent to the apparatus restarting unit 108. If not, the apparatus waits again for a predetermined time. Further, the restart determination unit 109 determines whether or not the measured elapsed time is longer than the reception resumption time when there is no transmission request to the transmission / reception device 100. If it is not large, it waits for a certain time again.

  The device restart unit 108 restarts the transmission / reception device 100 when a request to restart the device is issued from the restart determination unit 109.

Next, the operation of the transmitting / receiving apparatus 100 of FIG. 1 will be described with reference to FIG.
When the transmitting / receiving apparatus 100 receives a packet, first, the demodulator 101 demodulates up to the PHY header 601 (step S201). The packet normality determination unit 102 determines whether the received packet is normal based on this demodulation result (step S202). If the packet normality determination unit 102 determines that the received packet is normal (Yes in step S202), the process proceeds to step S204. On the other hand, if the packet normality determination unit 102 determines that the received packet is not normal (No in step S202), the process proceeds to step S203. .

  In step S203, the reception interrupting unit 106 interrupts the transmission / reception device 100 from receiving this packet. On the other hand, in step S <b> 204, the demodulation unit 101 starts demodulating the MAC header 602 and demodulates up to the destination information 6021 included in the MAC header 602. When the demodulation of the MAC header is started, the bit string included in the MAC header is output to the own station address determination unit 103 with time. When all the bit strings corresponding to the destination information 6021 are output to the own station address determining unit 103, the own station address determining unit 103 determines that the received packet is addressed to the own station based on the demodulation result up to the destination information 6021. It is determined whether or not (step S205). If the own station address determining unit 103 determines that the received packet is addressed to the own station (Yes in step S205), the process proceeds to step S206. On the other hand, if determined that the received packet is not addressed to the own station (No in step S205), step The process proceeds to S207.

  In step S <b> 206, the own station address determination unit 103 controls each unit so that the transmission / reception apparatus 100 continues to receive the packet. On the other hand, in step S207, the demodulation unit 101 demodulates up to the transmission stop information 6022 included in the MAC header 602, and the transmission stop time calculation unit 104 calculates the transmission stop time (TT) based on the demodulation result of the transmission stop information 6022. calculate.

  Subsequently, the demodulation unit 101 demodulates up to reception resumption information 6023 included in the MAC header 602, and the reception resumption time calculation unit 105 calculates a reception resumption time (TR) based on the demodulation result of the reception resumption information 6023 (step). S208). Then, after all the bit strings corresponding to the transmission stop information and the reception resumption information are output from the demodulation unit 101, the device stop unit 107 interrupts the reception of the packet and stops a part or all of the device (step S209).

  The restart determination unit 109 waits for a certain period of time after the transmission / reception device 100 is stopped, and then measures an elapsed time (TP) from the time when transmission is stopped (step S210). The restart determination unit 109 determines whether or not there is a transmission request in the transmission / reception device 100 (step S211). If the transmission / reception apparatus 100 has a transmission request (“Yes” in step S211), the process proceeds to step S212. On the other hand, if the transmission / reception apparatus 100 does not have a transmission request (“not” in step S211), the process proceeds to step S213. move on.

In step S212, the restart determination unit 109 determines whether or not the transmission stop time (TT) obtained in step S207 is smaller than the post-device stop elapsed time (TP) obtained in step S210. If the transmission stop time (TT) is shorter than the elapsed time (TP) after the apparatus stop (Yes in step S212), the process proceeds to step S214, and if not (No in step S212), the process returns to step S210.
On the other hand, in step S213, the restart determination unit 109 determines whether or not the reception restart time (TR) obtained in step S208 is smaller than the elapsed time (TP) after the apparatus stop obtained in step S210. If the reception resumption time (TR) is smaller than the elapsed time (TP) after the apparatus is stopped (Yes in step S213), the process proceeds to step S214, and if not (No in step S213), the process returns to step S210.
In step S <b> 214, the device restart unit 108 restarts the transmission / reception device 100.

Next, an example of a device part to be stopped when the device stop unit 107 stops a part of the transmission / reception device 100 will be described with reference to FIG. FIG. 3 is a block diagram illustrating the configuration of the demodulation unit 101. Here, an example in which the apparatus stopping unit 107 stops a part of the demodulating unit 101 is shown.
First, each unit included in the demodulation unit 101 will be briefly described. The demodulating unit 101 includes a radio unit 301, an ADC 302, and a digital signal demodulating unit 303. The radio unit 301 converts a radio signal input from the antenna into a baseband analog signal. The ADC 302 converts the converted baseband analog signal into a baseband digital signal. The digital signal demodulator 303 demodulates the converted baseband digital signal.

The device stop unit 107 stops some or all of the radio unit 301, the ADC 302, and the digital signal demodulation unit 303. For example, the apparatus stopping unit 107 may stop only the radio unit 301, may stop the radio unit 301 and the ADC 302, or may stop the radio unit 301 and the digital signal demodulation unit 303.
If the blocks constituting the radio unit 301 can be further subdivided, a part of the subdivision may be stopped. For example, the apparatus stopping unit 107 may stop blocks that take time until the performance stabilizes after restarting, stop other blocks, or preferentially stop blocks that consume a large amount of power. . An example of a block that takes time until performance stabilizes after the restart is a synthesizer, and an example of a block that consumes a large amount of power is an amplifier.

  As described above, according to the transmission / reception apparatus of the present embodiment, since it is possible to interrupt the reception of a packet that does not need to receive the entire packet, it is possible to save the power required for reception and to stop transmission. Since it is possible to recognize the time that must be received and the time that reception must be resumed, it is possible to make transmission collisions and reception delays less likely to occur.

(Second Embodiment)
A transmitting / receiving apparatus according to a second embodiment of the present invention will be described with reference to FIG. The transmission / reception device 400 of this embodiment differs from the transmission / reception device 100 of the first embodiment only in that a threshold determination device stop unit 407 is provided instead of the device stop unit 107 of the first embodiment. Other device portions of the transmission / reception device 400 of the present embodiment are the same as those of the transmission / reception device 100 of the first embodiment, and the same device portions are denoted by the same reference numerals and description thereof is omitted.

  As described above, the transmission / reception apparatus 400 of the present embodiment may erroneously determine the normality of a packet using the PHY header 601. For this reason, a threshold determination device stopping unit 407 is provided to prevent transmission delay even when the packet normality determination is incorrect. If the received packet is erroneously determined to be normal although it is not normal, the transmission stop time may be erroneously calculated. If the transmission stop time is erroneously calculated and the calculated transmission stop time becomes larger than the actual value, this transmission / reception device will stop transmission more than necessary, resulting in the transmission rate being It will cause a decline.

Therefore, the threshold determination device stop unit 407 defines a certain threshold for comparison with the transmission stop time, and determines whether or not the transmission stop time calculated by the transmission stop time calculation unit 104 is equal to or greater than this threshold. If the transmission stop time is equal to or greater than this threshold, the threshold determination device stop unit 407 instructs the demodulation unit 101 to continue reception and receive data up to the data portion 603 of the received packet. On the other hand, when the transmission stop time is smaller than this threshold, the threshold determination device stop unit 407 receives the packet after the transmission / reception device 100 receives all the bit strings corresponding to the transmission stop information and the reception resumption information. This is interrupted and a part or all of the transmission / reception apparatus 100 is stopped.
As this threshold value, for example, it is half of the maximum transmission stop time defined in the communication system. For example, in IEEE802.11a, the transmission stop time can be set to a very large value, but such a large value is rarely used in actual operation, and a value smaller than half of the maximum value is used. There are more. For this reason, it is highly possible that a value exceeding half of the maximum value is erroneously generated, and it is desirable to continue reception.

  Further, since the normality of the packet can be determined using information included in the data portion 603, the possibility of applying an erroneous transmission stop time can be further reduced.

Next, the operation of the transmission / reception device 400 of this embodiment will be described with reference to FIG. Steps similar to those in FIG. 2 which is the flowchart shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The flowchart of FIG. 5 is obtained by adding step S501 to the flowchart of FIG.
In step S501, the threshold determination device stop unit 407 compares the transmission stop time (TT) with a preset threshold (T0). If the transmission stop time (TT) is equal to or greater than the threshold (T0) (Yes in step S501), the process proceeds to step S206, and if it is less (No in step S501), the process proceeds to step S208.
Other operations of the transmission / reception device 400 are the same as those described in the flow of FIG. 2 shown in the first embodiment.

  As described above, according to the transmission / reception apparatus of this embodiment, the power required for reception can be saved, transmission collisions and reception delays can be made less likely to occur, and the transmission stop time is actually erroneously set. If the determination is longer, transmission is not stopped more than necessary, and transmission delay can be prevented.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram of a transmission / reception device according to a first embodiment of the present invention. The flowchart which shows operation | movement of the transmission / reception apparatus of FIG. The block diagram of the demodulation part of FIG. The block diagram of the transmission / reception apparatus concerning the 2nd Embodiment of this invention. The flowchart which shows operation | movement of the transmission / reception apparatus of FIG. The figure which shows an example of a structure of the packet which the transmission / reception apparatus concerning the 1st and 2nd embodiment of this invention receives.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Transmission / reception apparatus, 101 ... Demodulation part, 102 ... Packet normality determination part, 103 ... Local-address determination part, 104 ... Transmission stop time calculation part, 105 ... Resumption of reception Time calculation unit 106 ... Reception interruption unit 107 ... Device stop unit 108 ... Device restart unit 109 ... Restart determination unit 301 ... Radio unit 302 ... ADC , 303 ... Digital signal demodulator, 400 ... Transmitter / receiver, 407 ... Threshold determination device stop, 601 ... PHY header, 602 ... MAC header, 603 ... Data part, 6021 ..Destination information 6022... Transmission stop information 6023.

Claims (8)

A transmitting / receiving device for transmitting and receiving packets,
A conversion means for demodulating the packet and converting it into a bit string;
Normality determining means for determining whether or not the packet is normal based on error detection information for detecting an error included in the bit string;
Self-station-addressed determination means for determining whether the packet is addressed to the self-station based on the destination information included in the bit string;
A transmission stop time calculating means for calculating a transmission stop time based on the transmission stop information included in the bit string;
A reception resumption time calculating means for calculating a reception resumption time based on the reception resumption information included in the bit string;
When it is determined that the packet is normal and it is determined that the packet is not addressed to the local station, the transmission stop time and the reception resumption time are acquired, and reception is interrupted. Stop means to stop everything,
A transmission / reception apparatus comprising: restarting means for restarting part or all of the stopped transmission / reception apparatus based on the transmission stop time, the reception resumption time, and the transmission request of the transmission / reception apparatus. A transmitting / receiving device for transmitting and receiving packets,
A conversion means for demodulating the packet and converting it into a bit string;
Normality determining means for determining whether or not the packet is normal based on error detection information for detecting an error included in the bit string;
Self-station-addressed determination means for determining whether the packet is addressed to the self-station based on the destination information included in the bit string;
A transmission stop time calculating means for calculating a transmission stop time based on the transmission stop information included in the bit string;
A reception resumption time calculating means for calculating a reception resumption time based on the reception resumption information included in the bit string;
If it is determined that the packet is normal, the packet is not addressed to the local station, and the transmission stop time is smaller than a certain time, the reception resume time is acquired and reception is interrupted. Stop means for stopping a part or all of the transmission / reception device;
A transmission / reception apparatus comprising: restarting means for restarting part or all of the stopped transmission / reception apparatus based on the transmission stop time, the reception resumption time, and the transmission request of the transmission / reception apparatus. The converting means includes
Baseband conversion means for inputting the packet and converting it into a baseband signal;
Digital conversion means for converting the baseband signal into a digital signal;
Comprising demodulation means for demodulating the digital signal;
The transmission / reception apparatus according to claim 1, wherein the stop unit stops at least one of the baseband conversion unit, the digital conversion unit, and the demodulation unit.   The restarting unit waits for a predetermined time after the transmission / reception apparatus is stopped, and when there is a transmission request of the transmission / reception apparatus, and the predetermined time is longer than the transmission stop time, The transmission / reception apparatus according to any one of claims 1 to 3, wherein part or all of the stopped transmission / reception apparatus is activated again.   The restarting unit waits for a predetermined time after the transmission / reception apparatus stops, and when there is no transmission request from the transmission / reception apparatus and the predetermined time is longer than the reception resumption time, 5. The transmission / reception device according to claim 1, wherein a part or all of the stopped transmission / reception device is activated again.   The restarting unit waits for a predetermined time after the transmission / reception apparatus stops, and based on the transmission request of the transmission / reception apparatus, the fixed time, the transmission stop time, or the reception resumption time, 4. The transmission / reception apparatus according to claim 1, wherein a part or all of the stopped transmission / reception apparatus is activated again according to a result of the comparison. 5.   The normality determination unit determines whether or not the packet is normal based on information defined in a PHY (Physical Layer) header as the error detection information. Item 7. The transmission / reception device according to any one of items 6.   The local station address determining means determines whether the packet is addressed to the local station based on destination information included in a MAC (Medium Access Control) header as the destination information. The transmission / reception apparatus according to any one of claims 1 to 7.

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