JP2017168902A - Wireless communication method and wireless communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform transmission control considering interference given another system by monitoring an occupied frequency band of an own system and a usage status of its adjacent frequency band before transmission in a wireless environment where the occupied frequency band of the own system and the occupied frequency band of the other system overlap or are close to each other.SOLUTION: The wireless communication method includes: a step 1 of monitoring a frequency band adjacent to the occupied frequency band of the own system when a radio signal is not detected in the occupied frequency band of the own system; and, when a wireless signal is detected in the frequency band monitored in step 1, a step 2 of judging transmission permission/inhibition of the own system in consideration of interference given to another system.SELECTED DRAWING: Figure 1

Description

  The present invention performs transmission control by monitoring the usage status of the own system's occupied frequency band and its adjacent frequency bands before transmission in a wireless environment where the occupied frequency band of the own system and the occupied frequency band of another system overlap or are close to each other. The present invention relates to a wireless communication method and a wireless communication apparatus.

  In the IEEE802.11 standard (Non-Patent Document 1), for example, in the case of a wireless LAN of IEEE802.11a standard, in Japan, between 5170 MHz and 5330 MHz and between 5490 MHz and 5710 MHz, a total of 19 channels with 8 channels and 11 channels at 20 MHz intervals, respectively. A channel is specified.

  Thus, since the number of channels that can be used simultaneously in the same place is limited, when a wireless LAN is actually introduced, the wireless base station selects a channel to be used in its own BSS (Basic Service Set). Here, in a wireless environment where the number of BSSs is larger than the number of usable channels, a plurality of BSSs use the same channel. However, in order to avoid the influence of interference between BSSs, CSMA / CA (Carrier Sense Multiplexing) is used. Access with Collision Avoidance) is used to perform carrier sense in a channel to be used, and autonomous distributed access control is performed in which data is transmitted only when the channel is free.

  The channel selection method in the radio base station is not determined by the IEEE802.11 standard, so each vendor adopts its own method, but the most common channel selection method is the channel with the least interference power. There is a method for selecting the items in an autonomous and distributed manner. The radio base station performs carrier sensing for all channels for a certain period, selects a channel with the smallest interference power, and transmits / receives data to / from a terminal device under the selected channel. The interference power is a level of a signal received from a neighboring BSS or another system, and can be measured by, for example, a received signal strength indicator (RSSI).

IEEE802.11, "10.15.9 STA CCA sensing in a 20/40 MHz BSS"

  In CSMA / CA of a wireless LAN, only an occupied frequency band corresponding to a channel used in the own BSS is monitored (carrier sense) to determine whether or not transmission is possible so as not to interfere with neighboring BSSs using the same channel. . For example, in the transmission signal spectrum of the wireless LAN shown in FIG. 2, the monitor range is −10 MHz to +10 MHz including the occupied frequency band with respect to the center frequency of the channel. That is, the monitor bandwidth (resolution band) is 20 MHz.

  However, outside the occupied frequency band, there is out-of-band leakage power that satisfies the spectrum mask defined by the wireless LAN. In the frequency region of out-of-band leakage power, when another system is transmitting a radio signal as shown in FIG. 2, the own system transmits the radio signal outside the monitor range without being detected. Here, when the occupied frequency bandwidth of the other system is small, it is assumed that large interference is given to the other system due to out-of-band leakage power of the own system.

  Therefore, when the own system determines whether or not transmission is possible, it can be said that it is desirable to monitor the usage status of the out-of-band leakage power adjacent to the occupied frequency band of the own system. However, in the frequency region adjacent to the occupied frequency band of the own system, for example, when monitoring with a monitor bandwidth of 20 MHz, even if a signal of another system can be detected, the center frequency or the occupied frequency band cannot be determined, and the own system It is not possible to accurately evaluate the influence of interference on other systems by the out-of-band leakage power.

  The present invention monitors the utilization status of the own system's occupied frequency band and its adjacent frequency band before transmission in a wireless environment where the occupied frequency band of the own system and the occupied frequency band of the other system overlap or are close to each other. It is an object of the present invention to provide a wireless communication method and a wireless communication apparatus that can perform transmission control in consideration of interference.

  According to a first aspect of the present invention, in a wireless environment in which the occupied frequency band of the own system and the occupied frequency band of another system overlap or are close to each other, the radio that stops transmission when the occupied frequency band of the own system is monitored and a radio signal is detected. In the communication method, when a radio signal is not detected in the occupied frequency band of the own system, the radio signal is detected in step 1 for monitoring the frequency band adjacent to the occupied frequency band of the own system and in the frequency band monitored in step 1 In this case, there is a step 2 of determining whether or not transmission of the own system is possible in consideration of interference given to other systems.

  In the wireless communication method of the first invention, the frequency band adjacent to the occupied frequency band of the own system is a frequency band in which the out-of-band leakage power of the transmission signal of the own system is a predetermined value or more.

  In the wireless communication method of the first invention, step 1 monitors a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system, and step 2 detects the signal level and occupation of the detected wireless signal. The frequency band is analyzed, the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system is predicted, the SIR in the other system is calculated, and whether or not the own system can transmit is determined according to the SIR.

  In the wireless communication method of the first invention, step 1 monitors a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system, and step 2 detects the signal level and occupation of the detected wireless signal. Analyzing the frequency band, identifying the other system and its required SIR based on the obtained occupied frequency band, predicting the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system, and the SIR in the other system If the SIR in the other system satisfies the required SIR by adjusting the transmission output of the own system, the transmission output is adjusted and transmitted if the required SIR is satisfied, and the required SIR is not satisfied. Stop sending.

  The second invention is a control for stopping transmission when a radio signal is detected by monitoring the occupied frequency band of the own system in a wireless environment where the occupied frequency band of the own system and the occupied frequency band of another system overlap or are adjacent to each other. In the wireless communication apparatus provided with the means, the control means is configured to monitor a frequency band adjacent to the occupied frequency band of the own system when the wireless signal is not detected in the occupied frequency band of the own system; And a transmission control unit that determines whether or not transmission of the own system is possible in consideration of interference given to other systems when a radio signal is detected in the frequency band monitored in (1).

  In the wireless communication device of the second invention, the frequency band adjacent to the occupied frequency band of the own system is a frequency band in which the out-of-band leakage power of the transmission signal of the own system is a predetermined value or more.

  In the wireless communication device of the second invention, the monitor control unit is configured to monitor a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system, and the transmission control unit detects the detected radio signal The signal level and the occupied frequency band of the other system are analyzed, the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system is predicted, the SIR in the other system is calculated, and whether or not the own system can transmit according to the SIR It is the structure which determines.

  In the wireless communication device of the second invention, the monitor control unit is configured to monitor a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system, and the transmission control unit detects the detected radio signal Analyze the signal level and the occupied frequency band of the other system, identify the other system and its required SIR based on the obtained occupied frequency band, and predict the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system The SIR in the other system is calculated, and it is determined whether or not the SIR in the other system satisfies the required SIR by adjusting the transmission output of the own system. If the required SIR is satisfied, the transmission output is adjusted and transmitted. This is a configuration in which transmission is stopped when the condition is not satisfied.

  The present invention monitors the frequency band adjacent to the own system's occupied frequency band and detects a radio signal, the degree of interference that the transmission signal of the own system gives to other systems, for example, the occupied frequency band of the detected radio signal In consideration of the SIR in, it is possible to suppress interference with other systems due to transmission of the own system by determining whether or not the own system can transmit.

  The present invention can monitor a plurality of times by shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system. The frequency band can be analyzed, and the SIR in the occupied frequency band can be calculated.

  If the occupied frequency band of the radio signal detected in the frequency band adjacent to the occupied frequency band of the own system is found, the present invention identifies the other system and the required SIR, and adjusts the transmission output of the own system to adjust the other system. When the SIR in the above satisfies the required SIR, it becomes possible to adjust the transmission output for transmission.

It is a flowchart which shows the process sequence of Example 1 by the radio | wireless communication method of this invention. It is a figure which shows the signal spectrum of an own system and another system. It is a figure which shows the signal spectrum of an own system and another system. It is a figure explaining the acquisition procedure of the occupation frequency band of the radio signal of another system. It is a flowchart which shows the process sequence of Example 2 by the radio | wireless communication method of this invention. It is a figure which shows the Example structure of the radio | wireless communication apparatus of this invention.

Example 1
FIG. 1 shows a processing procedure of Embodiment 1 according to the wireless communication method of the present invention.
In FIG. 1, the wireless communication apparatus monitors the occupied frequency band of its own system before transmission (S1), and determines whether or not to detect a radio signal having a predetermined interference power or higher in the occupied frequency band of its own system ( S2). Here, when a radio signal having a predetermined interference power or higher is detected in the occupied frequency band of the own system, transmission is stopped (S3). When no radio signal is detected, a frequency band adjacent to the occupied frequency band is monitored. (S4), it is determined whether or not a radio signal is detected in the adjacent frequency band (S5). Here, when a radio signal is detected in the adjacent frequency band, it is determined whether or not the interference given to the other system by the transmission of the own system is equal to or less than a specified value (S6). (S3). On the other hand, if the specified value is not exceeded, or if no radio signal is detected in the adjacent frequency band, transmission processing is performed (S7).

  The frequency band adjacent to the occupied frequency band of the own system is a frequency band in which the out-of-band leakage power of the transmission signal of the own system is a predetermined value or more. For example, in the example of the signal spectrum shown in FIGS. 2 and 3, the monitor range for the center frequency of the transmission signal of the own system is −10 MHz to +10 MHz, and the frequency band adjacent to the occupied frequency band has an out-of-band leakage power −. -30 MHz to -10 MHz and 10 MHz to 30 MHz at 45 dBr or more.

  In the example shown in FIGS. 2 and 3, there is a radio signal of another system in a frequency band where the out-of-band leakage power of the transmission signal of the own system is −45 dBr or more. When the monitor range is shifted to a frequency band adjacent to the occupied frequency band of the own system and, for example, a radio signal is detected in the monitor range of 10 MHz to 30 MHz, the interference given to other systems by the transmission of the own system is taken into account. Determine whether the system can be sent.

  Here, according to the center frequency or occupied frequency band of the radio signal of the other system, the degree of interference that the out-of-band leakage power of the transmission signal of the own system gives to the other system is determined, and whether or not transmission of the own system is appropriately determined can do. For example, as shown in FIG. 2, it is assumed that the radio signal of the other system exists at a level 10 dB lower than the output of the own system in the vicinity of 18 MHz from the center frequency of the own system. At this time, the out-of-band leakage power of the transmission signal of the own system is at a level 25 dB lower than the output of the own system. Therefore, when the own system starts transmission, the SIR in the other system can be predicted to be about 15 dB. In addition, as shown in FIG. 3, when the radio signal of the other system exists at a level 10 dB lower than the output of the own system in the vicinity of 28 MHz from the center frequency of the own system, the out-of-band leakage power of the transmission signal of the own system. Is a level that is 40 dB lower than the output of the own system, and therefore when the own system starts transmission, it can be predicted that the SIR in the other system will be about 30 dB.

  In this way, the SIR of the other system due to the out-of-band leakage power of the transmission signal of the own system is estimated according to the center frequency or the occupied frequency band of the radio signal of the other system, and whether or not the own system can transmit is estimated according to the SIR. You may judge. For example, as shown in FIG. 2, transmission may be stopped if the SIR in the other system is about 15 dB, and transmission processing may be performed if the SIR in the other system is about 30 dB, for example, as shown in FIG. .

  By the way, when monitoring a frequency band adjacent to the occupied frequency band of the own system, a method of narrowing the monitor bandwidth (resolution band) from 20 MHz in the own system is conceivable, but a plurality of monitor bandwidths are prepared. This is undesirable because the device structure is complicated and large. On the other hand, if monitoring is performed with the monitoring bandwidth of its own system being 20 MHz, the presence or absence of a radio signal of another system can be determined, but the center frequency or occupied frequency band cannot be determined. Therefore, a method of acquiring the occupied frequency band of the other system by monitoring while gradually shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system will be described with reference to FIG. 4 is an enlarged view of the range of −12 MHz to 40 MHz in FIG.

  In FIG. 4, the radio signal of the other system exists in the range of 16.5 MHz to 19.5 MHz from the center frequency of the own system. Here, a state is shown in which monitoring is performed sequentially while shifting with a step bandwidth of 2 MHz with a monitor bandwidth of 20 MHz. Since the monitor range including the occupied frequency band of the own system is −10 MHz to +10 MHz, the monitor of the frequency band adjacent to the occupied frequency band of the own system is shifted from the monitor range −8 MHz to +12 MHz at an interval of 2 MHz. Radio signals of other systems are not detected from the monitor range -4 MHz to +16 MHz, but from the monitor range -2 MHz to +18 MHz to the monitor range +18 to +38 MHz, and not from the monitor range +20 MHz to +40 MHz. Therefore, it can be considered that the radio signal of another system exists in the range of +16 MHz to +20 MHz where the detection ranges overlap. Therefore, it can be estimated that the center frequency of the radio signal of the other system is at a position of +18 MHz from the center frequency of the own system that is in the middle. Note that, by further narrowing the step width of the monitor range, it is possible to more accurately estimate the occupied frequency band and center frequency of the radio signal of another system. Thereby, in the occupied frequency band of the radio signal of the other system, the out-of-band leakage power of the transmission signal of the own system is predicted to be about −25 dBr, and the SIR is 15 dB if the signal level of the radio signal of the other system is −10 dBr. It can be estimated that the transmission is stopped.

(Example 2)
If the occupied frequency band of the radio signal of the other system is known, the other system and its required SIR can be identified by referring to the database. When the required SIR of the other system is 30 dB, for example, as shown in FIG. 2, if the SIR in the other system is about 15 dB, the transmission output of the own system is reduced by about 15 dB, and the required SIR is satisfied. Can be made. On the other hand, as shown in FIG. 3, for example, if the SIR in another system is about 30 dB, transmission is possible without reducing the transmission output of the own system. The above processing procedure will be described as a second embodiment.

FIG. 5 shows a processing procedure of the second embodiment according to the wireless communication method of the present invention.
In FIG. 5, the wireless communication apparatus monitors the occupied frequency band of its own system before transmission (S11), and determines whether or not to detect a radio signal having a predetermined interference power or higher in the occupied frequency band of its own system (S11). S12). Here, when a radio signal having a predetermined interference power or higher is detected in the occupied frequency band of the own system, transmission is stopped (S13), and when no radio signal is detected, the monitor range of the frequency band adjacent to the occupied frequency band is detected. Is monitored while shifting (S14), and it is determined whether or not a radio signal is detected in each monitor range (S15). In the example shown in FIG. 4, when the range of +10 MHz to +30 MHz is monitored with a step width of 2 MHz with respect to the center frequency of the own system, the monitor range is shifted from −8 MHz to +12 MHz to the monitor range +28 MHz to +48 MHz. As shown in FIGS. 2 and 3, since the frequency band adjacent to the occupied frequency band of the own system is on both sides with respect to the center frequency, the frequency region on both sides is set as the monitor range.

  When monitoring is finished in all monitor ranges and no radio signal is detected, transmission processing is performed (S18). When a radio signal is detected in any monitor range, the signal level and occupied frequency band of the radio signal are analyzed. Then, the other system and its required SIR are identified based on the obtained occupied frequency band, and the SIR in the other system is calculated by predicting the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band (S16). ). Then, in the occupied frequency band of the radio signal of the other system, the transmission output of the own system is adjusted to determine whether or not the required SIR of the other system is satisfied (S17).

  Here, if the required SIR of another system cannot be satisfied even if the transmission output of the own system is adjusted, the transmission is stopped (S13). On the other hand, if the required SIR can be satisfied, the transmission output is adjusted and transmission processing is performed (S18).

  Note that the above description assumes the worst condition in which the transmitting station of the own system exists between the transmitting station and the receiving station of another system. The receiving station of the other system receives both the radio signal of the other system and the radio signal of the own system after being attenuated, but the required SIR can be satisfied by reducing the transmission output of the own system according to the above procedure.

FIG. 6 shows the configuration of an embodiment of the wireless communication apparatus of the present invention.
In FIG. 6, the reception processing unit 11 detects a radio signal in the occupied frequency band of the own system or an adjacent frequency band under the control of the monitor control unit 12. The monitor control unit 12 executes the processing procedure shown in FIG. 1 or 5 and refers to the database unit 13 as necessary. The database unit 13 stores in advance the correspondence between the other systems and the occupied frequency band and the required SIR of the other systems. The monitor control unit 12 monitors the monitor range by shifting the monitor range to the occupied frequency band of the own system and the adjacent frequency band according to the processing procedure shown in FIG. 1 or FIG. The frequency band is analyzed, and the other system and its required SIR are identified with reference to the database unit 13 based on the obtained occupied frequency band. The transmission control unit 14 determines whether transmission is possible based on the monitoring result of the monitor control unit 12, and controls the transmission processing unit 15 to stop transmission, perform transmission processing, or adjust transmission output.

  Here, an example in which the wireless communication device includes the database unit 13 has been shown. However, in the case where the wireless communication device is a wireless base station connected to the network, the control server on the network is accessed and the detected wireless signal is transmitted. Another system corresponding to the occupied frequency band and its required SIR may be acquired.

DESCRIPTION OF SYMBOLS 11 Reception processing part 12 Monitor control part 13 Database part 14 Transmission control part 15 Transmission processing part

Claims (8)

In a wireless communication method for stopping transmission when a radio signal is detected by monitoring the occupied frequency band of the own system in a wireless environment where the occupied frequency band of the own system and the occupied frequency band of another system overlap or are close to each other,
Monitoring a frequency band adjacent to the occupied frequency band of the own system when a radio signal is not detected in the occupied frequency band of the own system;
A wireless communication method comprising: a step of determining whether or not transmission of the own system is possible in consideration of interference given to the other system when a wireless signal is detected in the frequency band monitored in the step 1. The wireless communication method according to claim 1,
The frequency band adjacent to the occupied frequency band of the own system is a frequency band in which out-of-band leakage power of the transmission signal of the own system is a predetermined value or more. The wireless communication method according to claim 1,
The step 1 monitors a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system,
The step 2 analyzes the signal level and the occupied frequency band of the detected radio signal, predicts the out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system, and calculates the SIR in the other system. A wireless communication method characterized by calculating and determining whether or not the system can transmit according to the SIR. The wireless communication method according to claim 1,
The step 1 monitors a plurality of times while shifting the monitor range of the frequency band adjacent to the occupied frequency band of the own system,
The step 2 analyzes a signal level and an occupied frequency band of the detected radio signal, identifies the other system and its required SIR based on the obtained occupied frequency band, and performs the operation in the occupied frequency band of the other system. The SIR in the other system is calculated by predicting out-of-band leakage power of the transmission signal of the own system, and it is determined whether or not the SIR in the other system satisfies the required SIR by adjusting the transmission output of the own system. A wireless communication method characterized by adjusting and transmitting a transmission output when SIR is satisfied, and stopping transmission when the required SIR is not satisfied. Wireless communication provided with a control means for stopping transmission when a radio signal is detected by monitoring the occupied frequency band of the own system in a wireless environment in which the occupied frequency band of the own system and the occupied frequency band of another system overlap or are adjacent to each other In the device
The control means includes
A monitor control unit that monitors a frequency band adjacent to the occupied frequency band of the own system when a radio signal is not detected in the occupied frequency band of the own system;
And a transmission control unit that determines whether or not transmission of the own system is possible in consideration of interference given to the other system when a radio signal is detected in a frequency band monitored by the monitor control unit. Communication device. The wireless communication device according to claim 5, wherein
The wireless communication apparatus, wherein the frequency band adjacent to the occupied frequency band of the own system is a frequency band in which out-of-band leakage power of the transmission signal of the own system is a predetermined value or more. The wireless communication device according to claim 5, wherein
The monitor control unit is configured to monitor a plurality of times while shifting a monitor range of a frequency band adjacent to the occupied frequency band of the own system,
The transmission control unit analyzes a signal level and an occupied frequency band of the detected wireless signal, predicts out-of-band leakage power of the transmission signal of the own system in the occupied frequency band of the other system, and performs SIR in the other system. The wireless communication apparatus is characterized in that the transmission of the own system is determined according to the SIR. The wireless communication device according to claim 5, wherein
The monitor control unit is configured to monitor a plurality of times while shifting a monitor range of a frequency band adjacent to the occupied frequency band of the own system,
The transmission control unit analyzes a signal level and an occupied frequency band of the detected radio signal, identifies the other system and its required SIR based on the obtained occupied frequency band, and in the occupied frequency band of the other system Predicting the out-of-band leakage power of the transmission signal of the own system, calculating the SIR in the other system, and determining whether the SIR in the other system satisfies the required SIR by adjusting the transmission output of the own system; A wireless communication apparatus, characterized in that a transmission output is adjusted and transmitted when the required SIR is satisfied, and transmission is stopped when the required SIR is not satisfied.

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