JP2010272982A - Radio communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio communication equipment capable of suppressing power consumption by performing encryption/decryption processing without lowering throughput. <P>SOLUTION: The radio communication equipment includes: a determining means for comparing a transfer rate of transmission data with a first prescribed threshold; an encryption circuit for encrypting the transmission data when the transfer rate of the transmission data is higher than the first prescribed threshold as a result of comparison by the determining means; and an encrypting means by software, for encrypting the transmission data when the transfer rate of the transmission data is lower than the first prescribed threshold as the result of the comparison by the determining means, wherein the radio communication equipment stops the operation of the encryption circuit when the transfer rate of the transmission data is lower than the first prescribed threshold as the result of the comparison by the determining means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus that performs encryption / decryption processing on transmission / reception data.

  In recent years, with the development of wireless technology, there are many cases where what is conventionally connected by wire is changed to wireless connection. For example, LAN (Local Area Network) is mainly connected by Ethernet (registered trademark) represented by IEEE 802.3, but in recent years, connection by wireless LAN represented by IEEE 802.11 system is much information. Used in communication equipment. Since wireless uses radio waves, anyone may be able to intercept communication because of its physical characteristics. Therefore, it is indispensable to protect communication with security.

  When encrypting / decrypting communication data for security protection, use a CPU to implement encryption / decryption processing from software (hereinafter referred to as “software encryption / decryption processing”) ) In addition, there is a method of preparing a logic and combination circuit separately from the CPU and realizing encryption / decryption processing by this logic and combination circuit (hereinafter referred to as “hardware encryption / decryption processing”). Generally, hardware encryption / decryption processing can be performed faster than software encryption / decryption processing.

  In wireless communication, the amount of data that must be processed per unit time increases as communication is performed at a higher transfer rate. For this reason, more encryption / decryption processing takes time. In order to communicate at a high transfer rate, it is necessary to perform encryption / decryption processing at high speed.

  In wireless communication at a high transfer rate, encryption / decryption processing by software takes time for encryption / decryption processing, and it falls short of the processing time necessary to maintain the throughput, thus reducing the throughput. May be a factor. On the other hand, the encryption / decryption processing by hardware processing is faster than the encryption / decryption processing by software processing, so it is possible to perform wireless communication at a high transfer rate while maintaining the throughput. is there. However, since the circuit scale of the wireless communication device increases, there is a disadvantage that power consumption increases.

  Therefore, in order to reduce power consumption, for example, in Patent Document 1, encryption / decryption processing by software is started, but when encryption / decryption processing does not end within a specified time, by hardware A method of performing encryption / decryption processing is disclosed. Here, the specified time is determined by the use of the encryption / decryption result of the processing target data.

  However, in the method disclosed in Patent Document 1, no consideration is given to the transfer rate of transmission / reception data when performing transmission / reception with another apparatus.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless communication apparatus capable of performing encryption / decryption processing without reducing throughput and suppressing power consumption. To do.

  In order to solve the above-described problem, a wireless communication apparatus according to the present invention includes a determination unit that compares a transfer rate of transmission data with a first predetermined threshold, and a transfer rate of the transmission data as a result of comparison by the determination unit. When the transmission rate of the transmission data is lower than the first predetermined threshold as a result of comparison between the encryption circuit for encrypting the transmission data and the determination unit when the transmission data is higher than the first predetermined threshold And encryption means using software for encrypting the transmission data, and when the transfer rate of the transmission data is lower than the first predetermined threshold as a result of the comparison by the determination means, the encryption circuit The operation is stopped.

  According to the present invention, it is possible to perform encryption / decryption processing without reducing throughput, and to suppress power consumption.

It is a figure which shows an example of a structure of the radio | wireless communication apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the processing operation in the radio | wireless communication apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the threshold value table | surface used in the radio | wireless communication apparatus which concerns on embodiment of this invention. It is a figure which shows an example of a structure of the radio | wireless communication apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the processing operation in the radio | wireless communication apparatus which concerns on embodiment of this invention.

  Next, embodiments for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating an example of a configuration of a wireless communication apparatus according to an embodiment of the present invention. As shown in FIG. 1, a wireless communication device 1 includes a wireless communication calculation unit 14 that performs wireless communication processing, a CPU 11 that performs processing under the control of software 2, an encryption circuit that performs encryption / decryption processing by hardware, and The decryption circuit 12 is composed of a RAM 13 that holds data for encryption / decryption and data for outputting an encryption / decryption result. The software 2 performs a SW / HW determination process 22 that compares the transfer rate with a threshold value and an encryption / decryption process 21.

  FIG. 2 is a diagram illustrating an example of a processing operation in the wireless communication apparatus according to the embodiment of the present invention. In the following, processing operations performed in each of the transmission-side device and the reception-side device are shown. The processing operations are substantially the same except that encryption is performed at the transmitting device and decryption is performed at the receiving device.

  First, in the case of an apparatus on the transmission side, the CPU 11 reads the data processed by the wireless communication calculation unit 14 from the RAM 13 by the software 2. In the case of a receiving apparatus, the received transmission / reception data is read from the RAM 13. Each device performs a SW / HW determination process 22 for comparing the read transmission / reception data transfer rate with a predetermined threshold (S101). This threshold is determined from the time during which encryption / decryption processing can be performed without reducing throughput and the time required for encryption processing.

  As shown in FIG. 2, when the transfer rate of transmitted / received data exceeds the threshold (S101, Yes), in the encryption / decryption process by software, the encryption process does not keep up with the transfer rate and the throughput is reduced. In each device, hardware encryption / decryption processing that enables high-speed encryption / decryption processing is performed (S102). That is, in each device, the encryption / decryption processing is performed by the encryption circuit and the decryption circuit 12 shown in FIG. Then, the encryption / decryption processing result is written in the RAM 13.

  As shown in FIG. 2, when the transmission / reception data transfer rate does not exceed the threshold value (S101, No), it is possible to perform encryption / decryption processing by software without reducing the throughput. The device performs encryption / decryption processing by software. That is, the encryption / decryption process is performed by the software encryption / decryption process 21 shown in FIG. Then, the encryption / decryption processing result is written in the RAM 13. Here, when the encryption / decryption processing is performed by the software encryption / decryption processing 21, the clock supply of the encryption / decryption circuit 12 is stopped and the operation is stopped. By doing so, the power consumption of the wireless communication device can be suppressed.

  By doing this, if the transfer rate of the transmission / reception data is higher than a predetermined threshold, that is, if encryption / decryption processing is required at high speed, hardware encryption / decryption processing is performed. And a decrease in throughput can be prevented. In addition, when the transfer rate of transmission / reception data is lower than the threshold, that is, when encryption / decryption processing that is too fast is not required, encryption / decryption processing by software is possible without reducing throughput. It is possible to perform the encryption / decryption processing by software, stop the operation of the encryption circuit and the decryption circuit that perform the encryption / decryption processing by hardware, and suppress the power consumption of the wireless communication device become.

  For example, when communication is performed by wireless LAN, data can be divided into frames and transmitted (fragmentation). When fragmented and transmitted, the transfer rates of the divided frames are usually all the same. For this reason, if it is decided to perform encryption / decryption processing by software by determining the first transmitted divided frame, the operation of the encryption / decryption circuit is always performed until the last transmitted divided frame. The power consumption of the wireless communication apparatus can be efficiently suppressed.

  FIG. 3 is a threshold value table showing threshold values used for comparison with the transfer rate of transmission / reception data for each encryption method. In FIG. 3, for example, the encryption method applied to transmission / reception data belongs to any one of the encryption methods 1 to 3, and a threshold value is given to each encryption method. For example, as shown in FIG. 3, an encryption method that takes time for encryption / decryption processing has a low threshold value. In FIG. 3, the encryption method 3 takes the longest time for the encryption / decryption processing, the next method is the encryption method 2, and the encryption method 1 can perform the encryption / decryption processing in the shortest time. It is said. In the threshold table shown in FIG. 3, three types of threshold values are described as an example by an encryption method, but the number of threshold values is not limited. Here, the same threshold is set for the encryption process and the decryption process, but the threshold value for the encryption process and the threshold value for the decryption process may be different values.

  In FIG. 3, for example, when encryption is performed using an encryption method belonging to encryption method 1, the threshold is determined to be 50 Mbps. When communication is performed at a transfer rate of 48 Mbps in this encryption method, since the transfer rate does not exceed the threshold value, encryption / decryption processing is performed by the software encryption / decryption processing 21 shown in FIG. The decryption processing result is written into the RAM 13. At this time, since the encryption / decryption process is performed by the software encryption / decryption process 21, the clock supply to the encryption circuit and the decryption circuit 12 can be stopped and the operation can be stopped. Electric power can be suppressed.

  As described above, the threshold value table as shown in FIG. 3 is prepared and stored, and it is preferable to refer to it in the determination in the SW / HW determination processing 22. This threshold value table may be stored by adding another storage means to the configuration shown in FIG.

  Usually, the time required for encryption / decryption processing differs depending on the encryption method. By preparing a threshold table as described above, the threshold value for switching between encryption / decryption processing by hardware and encryption / decryption processing by software depending on the transfer rate can be changed to multiple encryption methods. It is possible to change by. In this way, switching between software encryption / decryption processing or hardware encryption / decryption processing corresponding to various encryption methods, and stopping the hardware operation when performing software encryption processing As a result, the power consumption of the wireless communication device can be suppressed without reducing the throughput.

  FIG. 4 is a block diagram showing an example of the configuration of the wireless communication apparatus according to the embodiment of the present invention. In this configuration, the error frame calculation process 23 can be newly performed by the software 2 in the configuration shown in FIG.

  When transmission / reception cannot be performed normally due to frame collision or the like, if there is a transmission / reception failure, the frame that has failed in transmission / reception is newly retransmitted. This reproduced frame is called a reproduction frame. The reproduced frame may be described so that the frame is a retransmitted frame. In this way, the receiving side receives a retransmission frame when transmission / reception fails, so if the reception side counts the number of times it has received a playback frame, the receiving side counts the number of reception errors. I understand.

  In a situation where there are many retransmission frames and reception error frames, the normal reception frame interval is long, so the throughput is greatly reduced. For this reason, it is not necessary to perform encryption / decryption processing at high speed in a situation where retransmission frames and reception error frames occur frequently. For this reason, in a situation where there are many retransmission frames and reception error frames, the encryption / decryption processing by software may be performed. Therefore, the error frame calculation process 23 calculates the ratio of the retransmission frame or the reception error frame, and compares this ratio with a predetermined error frame threshold. By this comparison, when the ratio of retransmission frames and reception error frames is large and small, when the ratio of retransmission frames and reception error frames is large, that is, when there are many retransmission frames and reception error frames, What is necessary is just to perform encryption / decryption processing by software.

  There are various methods for calculating the ratio of retransmission frames and reception error frames. For example, it is possible to count the number of retransmission frames during a certain predetermined time, or to check how many retransmission frames are out of a certain predetermined number of transmission / reception frames.

  FIG. 5 is a diagram illustrating an example of a processing operation performed in the wireless communication apparatus according to the embodiment of the present invention in the configuration illustrated in FIG. In the following, processing operations performed in each of the transmission-side device and the reception-side device are shown. The processing operations to be performed are almost the same except that the transmission side apparatus performs encryption and the reception side apparatus performs decryption.

  First, in the case of an apparatus on the transmission side, the CPU 11 reads the data processed by the wireless communication calculation unit 14 from the RAM 13 by the software 2. In the case of a receiving apparatus, the received transmission / reception data is read from the RAM 13. Next, as shown in FIG. 4, each device performs error frame calculation processing 23 for calculating the ratio of retransmission frames or reception error frames before performing SW / HW determination processing 22 (S201).

  As shown in FIG. 5, when the ratio of retransmission frames and reception error frames exceeds a predetermined error frame threshold value (S201, Yes), encryption / decryption processing by software is performed in each device (S203). . That is, in each device, encryption / decryption processing is performed by the software encryption / decryption processing 21 shown in FIG.

  When the ratio of the retransmission frame and the reception error frame does not exceed the predetermined error frame threshold value, the transmission / reception data transfer rate and the rate threshold value are compared by the SW / HW determination processing 22 shown in FIG. ).

  As shown in FIG. 5, when the transfer rate of transmission / reception data exceeds a predetermined threshold (S202, Yes), the encryption / decryption processing by hardware is performed in each device (S204). That is, in each device, the encryption / decryption processing is performed by the encryption circuit and the decryption circuit 12 shown in FIG. Then, the encryption / decryption processing result is written in the RAM 13.

  When the transfer rate of the transmission / reception data does not exceed the predetermined threshold (S202, No), encryption / decryption processing by software is performed in each device (S203). That is, in each device, encryption / decryption processing is performed by the software encryption / decryption processing 21 shown in FIG. The encryption / decryption processing calculation result is written in the RAM 13. At this time, the operation of the encryption circuit and the decryption circuit 12 is stopped, and the power consumption of the wireless communication apparatus is suppressed.

  By performing the processing operation as described above, in a situation where there are many retransmission frames and reception error frames, the encryption / decryption processing by software is automatically performed, and the encryption circuit and The operation of the decoding circuit can be stopped, and the power consumption of the wireless communication device can be suppressed.

  In the above-described example, a RAM is used as a storage medium for storing and reading data. However, the storage medium may be adopted in other storage media.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments thereof, various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. is there.

  In the wireless communication apparatus according to the present invention, the determination unit also compares the transfer rate of the received data with a second predetermined threshold value. As a result of the comparison by the determination unit, the transfer rate of the received data is The received data when the transfer rate of the received data is lower than the second predetermined threshold as a result of the comparison by the decoding circuit for decoding the received data when the received data is higher than the second predetermined threshold. And when the transfer rate of the received data is lower than the second predetermined threshold as a result of the comparison by the determination unit, the operation of the decoding circuit is stopped. You may make it do.

  Further, in the wireless communication apparatus according to the present invention, the encryption circuit and the software encryption means can perform encryption processing by a plurality of encryption methods, and the decryption circuit and the software encryption means Can be decrypted by decryption means corresponding to each of the plurality of encryption methods, and the first predetermined predetermined by the encryption method used by the encryption means and the encryption means by the software The threshold value and the second predetermined threshold value may be changed.

  In addition, the wireless communication apparatus according to the present invention includes a calculation unit that calculates a ratio of retransmission frames that are retransmitted due to failure in transmission / reception of the frame when the transmission data is divided into a plurality of frames and transmitted / received. The determination unit compares the transmission data transfer rate with the first predetermined threshold value when the ratio of the retransmission frames calculated by the calculation unit is lower than a third predetermined threshold value. And the transmission means determines that the transmission rate of the transmission data is the first predetermined threshold as a result of the comparison by the determination means when the ratio of the retransmission frames calculated by the calculating means is lower than a third predetermined threshold. When the transmission data is encrypted when the ratio of the retransmission frames calculated by the calculation means is lower than a third predetermined threshold; Result of the comparison by constant means, when the transfer rate of the transmission data is lower than the first predetermined threshold, may be to stop the operation of the encryption circuit.

  Further, in the wireless communication apparatus according to the present invention, when the transmission data is divided into a plurality of frames and transmitted / received, the calculation unit calculates a rate of receiving the retransmission frame, and the determination unit includes the calculation unit. When the ratio of receiving the retransmission frame calculated by the step is lower than a fourth predetermined threshold, the transfer rate of the received data is compared with a second predetermined threshold, and the software decoding means is When the rate of receiving the retransmission frame calculated by the calculation means is lower than a fourth predetermined threshold, and as a result of comparison by the determination means, the transfer rate of the received data is lower than the second predetermined threshold Decoding the received data, and when the rate of receiving the retransmission frame calculated by the calculating means is lower than a fourth predetermined threshold, Result of comparison by, when the transfer rate of the received data is lower than said second predetermined threshold, may be to stop the operation of the decoding circuit.

1 wireless communication device 11 CPU
12 Encryption circuit and decryption circuit 13 RAM
14 Wireless communication calculation unit 2 Software 21 Software encryption / decryption process 22 SW / HW determination process 23 Error frame calculation process

JP 2007-214639 A

Claims (5)

Determining means for comparing a transmission rate of transmission data with a first predetermined threshold;
An encryption circuit that encrypts the transmission data when a transfer rate of the transmission data is higher than the first predetermined threshold as a result of the comparison by the determination unit;
And, as a result of the comparison by the determination means, when the transmission rate of the transmission data is lower than the first predetermined threshold, the software encryption means for encrypting the transmission data,
As a result of the comparison by the determination means, when the transmission rate of the transmission data is lower than the first predetermined threshold, the operation of the encryption circuit is stopped. The determination means also compares the transfer rate of the received data with a second predetermined threshold value,
A decoding circuit for decoding the reception data when the transfer rate of the reception data is higher than the second predetermined threshold as a result of the comparison by the determination means;
And, as a result of the comparison by the determination means, when the transfer rate of the reception data is lower than the second predetermined threshold value, the software decoding means for decoding the reception data,
2. The wireless communication apparatus according to claim 1, wherein when the transfer rate of the received data is lower than the second predetermined threshold as a result of the comparison by the determination unit, the operation of the decoding circuit is stopped. . The encryption means by the encryption circuit and the software can perform encryption processing by a plurality of encryption methods,
The decryption circuit and the software encryption means can be decrypted by a decryption means corresponding to each of the plurality of encryption methods,
3. The first predetermined threshold value and the second predetermined threshold value are changed by an encryption method used by the encryption circuit and the encryption means by the software. Wireless communication device. When the transmission data is transmitted and received by being divided into a plurality of frames, calculation means for calculating a ratio of retransmission frames retransmitted due to failure in transmission / reception of the frame,
The determination unit compares the transmission data transfer rate with the first predetermined threshold when the ratio of the retransmission frames calculated by the calculation unit is lower than a third predetermined threshold;
The software encryption means determines that the transmission rate of the transmission data is the first transmission data rate when the ratio of the retransmission frames calculated by the calculation means is lower than a third predetermined threshold, and as a result of comparison by the determination means. When the transmission data is lower than a predetermined threshold of
When the ratio of the retransmitted frame calculated by the calculating means is lower than a third predetermined threshold and when the transfer rate of the transmission data is lower than the first predetermined threshold as a result of the comparison by the determining means The wireless communication apparatus according to claim 1, wherein the operation of the encryption circuit is stopped. The calculation means calculates the rate of receiving the retransmission frame when the transmission data is divided into a plurality of frames and transmitted / received,
The determination means compares the transfer rate of received data with a second predetermined threshold when the rate of receiving the retransmission frame calculated by the calculation means is lower than a fourth predetermined threshold;
The software decoding means, when the ratio of receiving the retransmission frame calculated by the calculating means is lower than a fourth predetermined threshold, and as a result of the comparison by the determining means, the transfer rate of the received data is When lower than a second predetermined threshold, the received data is decoded;
When the rate at which the retransmission frame calculated by the calculation means is lower than a fourth predetermined threshold, and as a result of comparison by the determination means, the transfer rate of the received data is lower than the second predetermined threshold 5. The wireless communication apparatus according to claim 4, wherein the operation of the decoding circuit is stopped.

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