JP2019153884A - Communication device, control method of the same, and program - Google Patents

Abstract

[Purpose] To suppress a decrease in transmission throughput due to the use of an erroneous detection level. [Structure] A communication device that communicates in a network is a level indicating the received signal strength of a signal to be detected, and a first detection level for detecting a first signal by the first communication method is set. , It is determined whether or not there is another communication device that communicates by the first communication method in the vicinity of the communication device. The communication device raises the first detection level when it is determined that there is no other communication device communicating by the first communication method in the vicinity of the communication device. [Selection diagram] FIG. 4

Description

  The present invention relates to a communication device, a communication device control method, and a program.

  In a wireless local area network (LAN) conforming to the IEEE 802.11 series, it is obliged to confirm the availability of a transmission channel before transmission in order to prevent interference. As a method for checking the availability, two methods are defined in IEEE 802.11. The first method is a CS (Carrier Sense) method that detects only radio waves of a wireless LAN, and the second method is an ED (Energy) that detects the energy of a radio wave regardless of whether it is a radio wave of a wireless LAN. Detect) method. Each of the CS system and the ED system has a radio wave energy intensity level for detection (hereinafter, a detection level). In general, the detection level of the CS method is lower than the detection level of the ED method. For example, the detection level of the CS method is -82 dBm, and the detection level of the ED method is -70 dBm.

  On the other hand, IEEE 802.11 specifies that communication by the DSSS scheme and the OFDM scheme is possible. DSSS is Direct Sequence Spread Spectrum, and OFDM represents Orthogonal Frequency Divisional Multiplexing. Patent Document 1 proposes a configuration of a communication apparatus capable of performing wireless LAN communication using the DSSS scheme and the OFDM scheme and transmitting and receiving a DSSS signal and an OFDM signal.

JP 2006-295465 A

  As described above, a communication apparatus that performs wireless LAN communication compliant with the IEEE802.11 series can check the availability of a transmission channel before transmission using the CS method and the ED method. Since the detection level of the CS system is generally lower than the detection level of the ED system, it is appropriate to detect signals other than the wireless LAN using the detection level of the ED system. However, depending on the type of signal, the communication apparatus should use the detection level of the ED method to check the vacant state of the transmission channel. However, the communication device may erroneously use the detection level of the CS method. As a result, a signal with a low energy level that should not be detected is detected, so that the probability of transmission stoppage increases and the transmission throughput decreases.

  In addition, a communication device that can receive a DSSS signal and an OFDM signal as described in Patent Document 1, for example, erroneously sets the CS system detection level set for the DSSS signal in an environment where the DSSS signal is not received. May be used. In this case as well, detection of a signal having a low energy level that should not be detected originally increases the transmission stop probability and causes a decrease in transmission throughput.

  The present invention has been made in view of the above problems, and an object thereof is to suppress a decrease in transmission throughput due to the use of an incorrect detection level.

  As a means for achieving the above object, the communication apparatus of the present invention has the following configuration. That is, a communication device that performs communication in a network, and is a level indicating a received signal strength of a signal to be detected, and sets a first detection level for detecting a first signal by the first communication method And setting means for determining whether or not there is another communication device that communicates with the first communication method in the vicinity of the communication device, and the periphery of the communication device is determined by the determination means. The setting means increases the first detection level when it is determined that there is no other communication device communicating with the first communication method.

  According to the present invention, it is possible to suppress a decrease in transmission throughput caused by using an incorrect detection level.

2 shows a configuration example of a network in the embodiment. 1 shows a configuration example of a communication apparatus 101 according to a first embodiment. An example of a functional configuration of the control unit 108 of the communication apparatus 101 is shown. It is a flowchart of the process of the communication apparatus 101 in 1st Embodiment. The structural example of the communication apparatus 101 in 2nd Embodiment is shown. It is a flowchart of the process of the communication apparatus 101 in 2nd Embodiment. The structural example of the received packet in 2nd Embodiment is shown.

  Hereinafter, the present invention will be described in detail based on an example of an embodiment with reference to the accompanying drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

[First Embodiment]
(Network configuration)
FIG. 1 shows a network configuration of a wireless LAN in the present embodiment. In the present embodiment, a network 105 is composed of a plurality of communication devices 101 to 104 that function as wireless LAN terminals or access points. In the present embodiment, it is assumed that the communication apparatus 101 performs wireless LAN communication conforming to the IEEE (The Institute of Electrical and Electronics Engineers. Inc.) 802.11 series with other communication apparatuses in the network 105. Here, the communication apparatus 101 can detect a wireless LAN signal and a signal other than the wireless LAN from inside and outside the network 105.

(Configuration of communication apparatus 101)
The configuration of the communication apparatus 101 in this embodiment will be described with reference to FIGS. Here, a configuration related to reception processing, which is processing related to the present embodiment, will be described. FIG. 2 is a diagram illustrating a configuration example of the communication apparatus 101 according to the present embodiment. Each component shown in FIG. 2 is configured by hardware or software. When configured as software, a computer program for realizing each function is stored in the memory 206, and the function is realized by the control unit 205 executing the program.

  As an example of the configuration of the communication apparatus 101, an antenna unit 201, a high frequency processing unit 202, a baseband processing unit 203, a medium access management unit 204, a control unit 205, a memory 206, a communication interface 207, a display unit 208, and an input unit 209. The baseband processing unit 203 includes a DSSS (Direct Sequence Spread Spectrum) processing unit 211 and an OFDM (Orthogonal Frequency Divisional Multiplexing) processing unit 212.

  The antenna unit 201 receives a radio signal transmitted from another communication device or the like in the network 105. The high frequency processing unit 202 converts the radio signal received by the antenna unit 201 into a baseband signal. In the baseband processing unit 203, after an A / D (analog / digital) conversion unit (not shown) converts the baseband signal into a digital signal, the DSSS processing unit 211 and the OFDM processing unit 212 respectively perform DSSS demodulation processing and OFDM. Performs demodulation processing. The digital signal demodulated by the baseband processing unit 203 is subjected to digital signal processing such as header processing by the medium access management unit 204 and is sent to the control unit 205. The control unit 205 has various functions and controls the communication device 101 as a whole. The functional configuration of the control unit 205 will be described later. The memory 206 stores a program executed by the control unit 205 for controlling the communication device 101. The memory 206 stores data from the medium access management unit 204 and the like. The communication interface 207 performs data transmission / reception processing to an external device or an external unit (not shown). A display unit 208 displays a result of various data processing performed by the control unit 205. The input unit 209 is used for inputting various settings or commands instructed by the user.

  Next, the DSSS processing unit 211 and the OFDM processing unit 212 will be described in more detail. In the DSSS processing unit 211, a detection level setting unit 301 described later sets a CS detection level (DSSS CS detection level) and an ED detection level (DSSS ED detection level). The DSSS processing unit 211 determines the received signal strength of the wireless LAN signal using the DSSS CS detection level, detects a signal with the received signal strength equal to or higher than the DSSS CS detection level, and demodulates the signal according to the DSSS method. Similarly, the DSSS processing unit 211 determines the received signal strength using the DSSS ED detection level for signals other than the wireless LAN, detects a signal whose received signal strength is equal to or higher than the DSSS ED detection level, and demodulates the signal according to the DSSS method. .

  Also, in the OFDM processing unit 212, the detection level setting unit 301 sets the CS detection level (OFDM CS detection level) and the ED detection level (OFDM ED detection level). For the wireless LAN signal, the OFDM processing unit 212 determines the received signal strength using the OFDM CS detection level, detects a signal with the received signal strength equal to or higher than the OFDM CS detection level, and demodulates the signal according to the OFDM communication scheme. Similarly, the OFDM processing unit 212 determines the received signal strength using the OFDM ED detection level for signals other than the wireless LAN, detects a signal with the received signal strength equal to or higher than the OFDM ED detection level, and demodulates the signal according to the OFDM communication method. To do.

  Next, the functional configuration of the control unit 205 will be described. The control unit 205 is configured by one or more CPUs (Central Processing Units) or MPUs (Micro Processing Units), and controls the entire communication apparatus 101 by executing a program stored in the memory 206. FIG. 3 shows a functional configuration example in the control unit 205. The control unit 205 includes a detection level setting unit 301, a parameter setting unit 302, a determination unit 303, a data management unit 304, a communication control unit 305, an input / output control unit 306, and a timer unit 307 as an example of the functional configuration.

  The detection level setting unit 301 sets the above-described DSSS CS detection level, DSSS ED detection level, OFDM CS detection level, and OFDM ED detection level for the baseband processing unit 203. The parameter setting unit 302 sets parameters related to various processes in the baseband processing unit 203 and the medium access management unit 204. Based on the demodulation results of the DSSS processing unit 211 and the OFDM processing unit 212, the determination unit 303 determines whether there is another communication device in the communication channel that communicates with the DSSS system or the OFDM communication system in the vicinity. The data management unit 304 manages data stored in the memory 206. The communication control unit 305 controls communication processing in the communication interface 207. The input / output control unit 306 performs display control on the display unit 208 and transmits a command or the like input by the input unit 209 to each component of the communication apparatus 101. The timer unit 307 performs timing processing.

(Process flow)
Next, the operation of the communication apparatus 101 in this embodiment will be described with reference to FIG. FIG. 4 is a flowchart of processing of the communication apparatus 101 according to the first embodiment. The flowchart shown in FIG. 4 can be realized by the control unit 205 executing a control program stored in the memory 206 to execute calculation and processing of information and control of each hardware.

  First, in S401, the detection level setting unit 301 sets the DSSS ED detection level to -70 dBm, the OFDM ED detection level to -70 dBm, and the OFDM CS detection level to -82 dBm. Subsequently, in S402, the detection level setting unit 301 sets the DSSS CS detection level to -82 dBm. After setting the various detection levels in S401 and S402, in S403, the control unit 205 of the communication apparatus 101 holds a signal received during a first predetermined time (for example, 1 second) in the memory 206 as peripheral communication information. . The first predetermined time is measured by the timer unit 307. After the elapse of the first predetermined time, in step S404, the control unit 205 of the communication apparatus 101 determines whether there is a communication apparatus that communicates with the DSSS system in the vicinity. Specifically, the determination unit 303 determines whether the signal received during the first predetermined time is correctly demodulated by the DSSS processing unit 211. If it is determined by the determination unit 303 that the DSSS processing unit 211 has correctly demodulated, that is, if it is determined that there is a communication device that communicates with the DSSS system in the vicinity (Yes in S404), the process returns to S402.

  On the other hand, when it is determined by the determination unit 303 that the DSSS processing unit 211 has not correctly demodulated, that is, when it is determined that there is no communication device that communicates with the DSSS system in the surroundings (No in S404), the process is S405. Proceed to Even if no signal is received during the first predetermined time, it is determined that there is no communication apparatus that communicates with the DSSS system in the vicinity (No in S404), and the process proceeds to S405. In S405, the detection level setting unit 301 sets the DSSS CS detection level to −70 dBm for the DSSS processing unit 211. That is, the DSSS CS detection level is relaxed from −82 dBm to −70 dBm. As a result, the DSSS processing unit 211 does not detect an interference signal of, for example, −75 dBm, which has been erroneously detected in the past, so that the transmission stop probability due to erroneous detection is effectively reduced.

  After the DSSS CS detection level is set to -70 dB in S405, in S406, the control unit 205 checks whether a second predetermined time (for example, 10 seconds) has elapsed. The second predetermined time is measured by the timer unit 307. After the elapse of the second predetermined time (Yes in S406), the process returns to S402. As a result, even when a new device that communicates with the DSSS system enters the periphery of the communication device 101, the device can be recognized, and the communication device 101 and the device can coexist.

  As described above, the communication apparatus 101 according to the present embodiment relaxes the DSSS CS detection level when there is no apparatus that communicates with the DSSS system around the communication apparatus 101. Thereby, for example, even if the DSSS processing unit 211 of the communication apparatus 101 should determine the received signal strength by using the DSSS ED detection level, the DSSS CS detection level is erroneously used. Prevent detection. Thereby, it is possible to suppress an increase in the probability of stopping transmission by the communication apparatus 101, and it is possible to avoid a decrease in the throughput of transmission. In addition, although this embodiment demonstrated controlling DSSS CS detection level, it is also possible to control OFDM CS detection level. That is, the OFDM CS detection level may be increased when there is no communication apparatus that communicates with the OFDM system in the vicinity.

[Second Embodiment]
In the first embodiment, a mode has been described in which the DSSS CS detection level is alleviated when there is no device that communicates in the DSSS system around the communication device 101. In the present embodiment, when the communication apparatus 101 can communicate with two types of OFDM communication schemes, control when there is no other apparatus in the vicinity that communicates with one communication scheme of the two types of OFDM signals will be described. To do. In the following, description of items common to the first embodiment will be omitted.

(Configuration of communication apparatus 101)
The configuration of the communication apparatus 101 in this embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a configuration example of the communication apparatus 101 according to the present embodiment. Similar to the first embodiment, a configuration related to a reception process, which is a process related to the present embodiment, will be described here. In addition, the structure of the baseband process part 203 differs compared with FIG. 2 demonstrated in 1st Embodiment. The baseband processing unit 203 in the present embodiment includes a first OFDM processing unit 511, a second OFDM processing unit 512, and an ED detection unit 513. The first OFDM processing unit 511 can demodulate an OFDM signal (first OFDM signal) with a subcarrier interval of 312.5 kHz (for example, IEEE 802.11ac) as a signal based on the first OFDM communication scheme. In addition, the second OFDM processing unit 512 can demodulate a subcarrier spacing 78.125 kHz (for example, IEEE 802.11ax) OFDM signal (second OFDM signal) as a signal based on the second OFDM communication scheme.

  The functional configuration of the control unit 205 is the same as that of FIG. 3 described in the first embodiment. However, the detection level setting unit 301 performs the first OFDM CS detection level, the second OFDM CS detection level, and the ED detection level for each of the first OFDM processing unit 511, the second OFDM processing unit 512, and the ED detection unit 513. Set. The first OFDM processing unit 511 compares the first OFDM CS detection level with the received signal strength, detects a signal with the received signal strength equal to or higher than the first OFDM CS detection level, and demodulates the signal according to the first OFDM communication scheme. Second OFDM processing section 512 compares the second OFDM CS detection level with the received signal strength, detects a signal with the received signal strength equal to or higher than the second OFDM CS detection level, and demodulates the signal according to the second OFDM communication scheme. The ED detection unit 513 determines the received signal strength using the ED detection level for signals other than the wireless LAN, and detects a signal having a received signal strength equal to or higher than the ED detection level.

(Process flow)
Next, the operation of the communication apparatus 101 in this embodiment will be described with reference to FIG. FIG. 6 is a flowchart of processing of the communication apparatus 101 according to the second embodiment. The flowchart shown in FIG. 4 can be realized by the control unit 205 executing a control program stored in the memory 206 to execute calculation and processing of information and control of each hardware.

  First, in S601, the detection level setting unit 301 sets the ED detection level to -70 dBm, the first OFDM CS detection level to -82 dBm, and the second OFDM CS detection level to -82 dBm. After setting various detection levels, the control unit 205 of the communication apparatus 101 holds a signal received during a first predetermined time (for example, 1 second) as peripheral communication information. The first predetermined time is measured by the timer unit 307. After the elapse of the first predetermined time, in step S602, the control unit 205 of the communication apparatus 101 determines whether there is a communication measure for performing communication using the first OFDM communication method. Specifically, the determination unit 303 analyzes the signal received during the first predetermined time demodulated by the first OFDM processing unit 511 and the second OFDM processing unit 512, thereby determining the determination. I do.

  An example of the determination in S602 will be described with reference to FIGS. 7A and 7B. FIG. 7A illustrates a packet configuration example of the first OFDM signal obtained by demodulation by the first OFDM processing unit 511. FIG. 7B is a configuration example of a second OFDM signal packet obtained by demodulation by the second OFDM processing unit 512. As can be seen from FIG. 7A, the packet of the first OFDM signal is composed of a first preamble for OFDM signal and a payload. As can be seen from FIG. 7B, the packet of the second OFDM signal includes a first OFDM signal preamble, a second OFDM signal preamble, and a payload. Therefore, when the configuration of the OFDM signal demodulated by the first OFDM processing unit 511 and the second OFDM processing unit 512 is the configuration of FIG. 7A, the determination unit 303 performs communication using the first OFDM communication scheme. It is determined that there is a communication device to be used.

  As another example of the determination in S602, the determination unit 303 includes information in the information element in the management frame of the wireless LAN demodulated by the first OFDM processing unit 511 and the second OFDM processing unit 512. Is used. For example, the determination unit 303 determines that there is a communication apparatus that communicates in the first OFDM communication method when ID = 255 indicating information on the second OFDM communication method does not exist in the information element.

  If it is determined in S602 that there is no communication apparatus that communicates with the first OFDM signal system (No in S602), the process proceeds to S604. In S604, the detection level setting unit 301 sets the first OFDM CS level to -62 dBm and the ED detection level to -62 dBm. This makes it possible to reduce the transmission stop probability due to erroneous detection by the first OFDM processing unit 511. Subsequently, in S606, the control unit 205 confirms whether or not a second predetermined time (for example, 5 seconds) has elapsed. The second predetermined time is measured by the timer unit 307. After the elapse of the second predetermined time (Yes in S606), the process returns to S601.

  If it is determined in S602 that there is a communication apparatus that communicates using the first OFDM signal scheme (Yes in S602), the process proceeds to S603. In step S <b> 603, the determination unit 303 determines whether a communication apparatus that communicates using the first OFDM communication scheme exists in the network 105 to which the communication apparatus 101 belongs. Specifically, the determination unit 303 performs the determination by analyzing the signals demodulated by the first OFDM processing unit 511 and the second OFDM processing unit 512. For example, the determination unit 303 determines that a device that uses the first OFDM signal exists in the network 105 when the information identifying the affiliated network included in the demodulated signal corresponds to the network 105. . An example of information for identifying the belonging network is a BSSID (Basic Service Set Identifier). As another example of the determination in S603, the determination unit 303 uses information regarding the group of the affiliated network included in the demodulated signal. The determination unit 303 determines that a communication apparatus that communicates using the first OFDM communication system exists in the network 105 when the information regarding the group of the belonging network matches the information regarding the group of the network 105.

  If it is determined that a communication apparatus that communicates using the first OFDM communication method exists in the network 105 (Yes in S603), the process returns to S601. On the other hand, when it is determined that a communication apparatus that communicates using the first OFDM communication scheme does not exist in the network 105, that is, an apparatus that uses the first OFDM signal exists in a network adjacent to the network 105 (S603). No), the process proceeds to S605. In S605, the detection level setting unit 301 changes the first OFDM CS detection level from -82 dBm set in S601, sets it to -70 dBm, and relaxes the carrier sense sensitivity. Thereby, it is possible to reduce a decrease in throughput in the network 105 due to carrier sense of the first OFDM signal from the adjacent network. After the detection level setting unit 301 sets the first OFDM CS detection level to −70 dBm in S605, in S607, the control unit 205 checks whether a third predetermined time (for example, 5 seconds) has elapsed. The third predetermined time is counted by the timer unit 307. After the elapse of the third predetermined time (Yes in S607), the process returns to S601.

  As described above, the communication apparatus 101 according to the present embodiment reduces the transmission stop probability due to the false detection of the first OFDM processing unit 511 and reduces the carrier sense sensitivity of the first OFDM signal from the adjacent network. Thereby, it is possible to reduce a decrease in throughput of the network to which the communication apparatus 101 belongs.

  In the above embodiment, the communication device 101 is assumed to be a communication device that can receive and demodulate signals using two communication methods. However, the communication device 101 receives and uses signals of one or more communication methods. A communication device capable of demodulation may be used.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

201 antenna unit, 202 high frequency processing unit, 203 baseband processing unit, 204 medium access management unit, 205 control unit, 206 memory, 207 communication interface, 208 display unit, 209 input unit

Claims (13)

A communication device for performing communication in a network,
A setting means for setting a first detection level for detecting a first signal according to the first communication method, which is a level indicating a received signal strength of a signal to be detected;

Determining means for determining whether there is another communication device that communicates with the first communication method around the communication device;
The setting means increases the first detection level when it is determined by the determination means that there is no other communication apparatus communicating with the first communication method around the communication apparatus. Communication device.   The said setting means raises the said 1st detection level, when the said determination means determines with the other communication apparatus which communicates by the said 1st communication system existing outside the said network. Item 4. The communication device according to Item 1.   3. The communication apparatus according to claim 2, wherein the setting unit sets a second detection level for detecting a second signal based on a second communication method different from the first communication method. First processing means for detecting and demodulating a signal having a received signal strength greater than the first detection level as the first signal;
A second processing means for detecting and demodulating a signal having a received signal strength greater than the second detection level as the second signal;
The determination means is based on a signal obtained by demodulation by the first processing means and the second processing means, and another communication device that communicates with the first communication method exists outside the network. The communication apparatus according to claim 3, wherein it is determined whether or not.   The determination means determines whether or not there is another communication device that communicates with the first communication method around the communication device, using a signal received at a first predetermined time. The communication apparatus according to any one of claims 1 to 4.   When the first processing unit correctly demodulates the first signal, the determination unit determines that there is another communication device that communicates with the first communication method around the communication device. The communication apparatus according to claim 1.   The said setting means reduces the said 1st detection level after progress of the 2nd predetermined time, after raising the value of the said 1st detection level, The any one of Claim 1 to 6 characterized by the above-mentioned. The communication device described.   5. The first communication method is a DSSS (Direct Sequence Spread Spectrum) communication method, and the second communication method is an OFDM (Orthogonal Frequency Division Multiplexing) communication method. The communication device described   The first communication method is an OFDM communication method with a subcarrier interval of 312.5 kHz, and the second communication method is an OFDM communication method with a subcarrier interval of 78.125 kHz. 5. The communication device according to 3 or 4. A communication device,
A level indicating a received signal strength of a signal to be detected, which is a first detection level for detecting a signal according to the first communication method, and a signal according to the first communication method and another communication method. Setting means for setting a second detection level for
Determining means for determining whether there is another communication device that communicates with the first communication method around the communication device;
The setting means increases the first detection level when it is determined by the determination means that there is no other communication apparatus communicating with the first communication method around the communication apparatus. Communication device. A method for controlling a communication device that performs communication in a network,
A setting step for setting a first detection level for detecting the first signal according to the first communication method, which is a level indicating the received signal strength of the signal to be detected;

Determining whether there is another communication device communicating with the first communication method around the communication device, and
The determination step raises the first detection level when it is determined by the determination step that there is no other communication device communicating with the first communication method around the communication device. Method for controlling a communication device. A communication device control method comprising:
A level indicating a received signal strength of a signal to be detected, which is a first detection level for detecting a signal according to the first communication method, and a signal according to the first communication method and another communication method. A setting step for setting a second detection level for
Determining whether there is another communication device communicating with the first communication method around the communication device, and
In the determination step, when it is determined that there is no other communication device that communicates with the first communication method around the communication device, the setting step increases the first detection level. Method for controlling a communication device.   The program for functioning a computer as a communication apparatus of any one of Claim 1 to 10.

Images