JP5545111B2 - Wireless device and wireless communication system including the same - Google Patents

Description

  The present invention relates to a wireless device that performs wireless communication and a wireless communication system including the same.

  In general, a wireless communication system includes a plurality of wireless devices. In the wireless communication system, when the wireless devices A and B are performing wireless communication with each other, the other wireless device C receives interference from the wireless devices A and B performing wireless communication.

  Therefore, when the other wireless device C performs wireless communication, it is necessary to perform the wireless communication with power that minimizes interference to the wireless communication performed by the wireless devices A and B. That is, the other wireless device C needs to perform wireless communication by controlling the transmission power.

  For this reason, theoretically, the wireless device C determines whether or not to perform wireless communication by the following method (Non-Patent Documents 1 to 4). The wireless device C performs wireless communication only when it is determined that the dominant eigenvalue of the matrix of network information is smaller than “1”. The matrix of network information is composed of elements including signal-to-interference and noise ratio (SINR) of all radio links in the radio communication system and channel gains of all radio devices in the radio communication system. The

J. Zander, “Distributed co-channel interference control in cellular radio systems”, IEEE Trans. Veh. Technol., Vol. 41, no. 4, pp. 305-311, Aug. 1992. G. Foschini and Z. Miljanic, “A simple distributed autonomous power control algorithm and its convergence”, IEEE Trans. Veh. Technol., Vol. 42, no. 4, pp. 641-646, Aug. 1993. T. Holliday, A. Goldsmith, P. Glynn, and N. Bambos, “Distributed power and admission control for time-varying wireless networks”, in Proc. Of IEEE Global Telecommunications Conference (Globecom), Dallas, Texas, Nov. 29 -Dec. 3, 2004, pp. 768-774. J. Luo, S. Ulukus, and A. Ephremides, “Standard and quasi-standard stochastic power control algorithms”, IEEE Trans Inform. Theory, vol. 51, no. 7, pp. 2612-2624, July 2005.

  However, there is a problem that the method of calculating eigenvalues of a matrix to determine whether wireless communication is possible or not is complicated when the number of matrix elements increases. Unfortunately, computing the eigenvalues of a matrix is difficult. There is no general closed formula for a network of more than four transmitter-receiver pairs. And the numerical method of the reference is very complicated, for example, due to the premise of the distributed inverse matrix or the exchange of global network information.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless device that can easily determine whether or not wireless communication is possible when receiving interference from another wireless device. That is.

  Another object of the present invention is to provide a wireless communication system including a wireless device that can easily determine whether or not wireless communication is possible when interference is received from another wireless device.

  According to the present invention, the wireless device includes a transmission unit, a reception unit, a calculation unit, and a determination unit. The transmission means executes a first process of transmitting Kmax (Kmax is 3 or more) probe signals at different timings with the first transmission power in the first frequency band. The receiving unit executes a second process of receiving, from the transmission destination, Kmax interference power obtained when the transmission destination receives Kmax probe signals. The calculation means divides the received interference power by the first transmission power, and executes a process for calculating an evaluation item by multiplying the division result by a predetermined parameter for Kmax interference powers. , Kmax evaluation items are acquired. The determination unit determines whether or not the Kmax-th evaluation item is smaller than 1. When it is determined that the Kmax-th evaluation item is smaller than 1, the transmission unit performs normal data with a second transmission power larger than the first transmission power in a second frequency band different from the first frequency band. Send a packet containing The predetermined parameter is a parameter that defines an evaluation function of a link between the wireless device and the transmission destination.

  According to the invention, the wireless communication system includes the first and second wireless devices. The first radio apparatus measures Kmax interference powers when receiving Kmax (Kmax is 3 or more) probe signals, and transmits the measured Kmax interference powers. The second radio apparatus executes a first process of transmitting Kmax probe signals to the first radio apparatus at different timings with the first transmission power in the first frequency band, and Kmax interference powers 2 is received from the first wireless device, the received interference power is divided by the first transmission power, and the evaluation result is calculated by multiplying the division result by a predetermined parameter. The process is performed on Kmax interference powers, Kmax evaluation items are acquired, and when it is determined that the Kmax evaluation item is smaller than 1, a second frequency band different from the first frequency band The packet including the normal data is transmitted to the first radio apparatus with the second transmission power larger than the first transmission power. The predetermined parameter is a parameter that defines an evaluation function of a link between the wireless device and the transmission destination.

  According to the present invention, the transmission source calculates Kmax evaluation items, and determines that wireless communication is possible when it is determined that the Kmax-th evaluation item is smaller than 1.

  Therefore, the transmission source can easily determine whether or not wireless communication is possible.

1 is a schematic diagram of a wireless communication network according to an embodiment of the present invention. FIG. 2 is a configuration diagram of the wireless device shown in FIG. 1 according to the first embodiment. It is a figure which shows the 1st example of the evaluation function determined for every service quality. It is a figure which shows the 2nd example of the evaluation function determined for every service quality. It is a figure which shows the 3rd example of the evaluation function determined for every service quality. It is a figure which shows the 4th example of the evaluation function determined for every service quality. It is a conceptual diagram of a frequency band. 4 is a conceptual diagram for explaining a wireless communication method according to Embodiment 1. FIG. 3 is a flowchart illustrating a wireless communication method according to the first embodiment. FIG. 3 is a configuration diagram of a wireless device shown in FIG. 1 in a second embodiment. 6 is a flowchart illustrating a wireless communication method according to the second embodiment. FIG. 7 is a configuration diagram of a wireless device shown in FIG. 1 in a third embodiment. It is a conceptual diagram for demonstrating the method of determining an extrapolation value. 10 is a flowchart illustrating a wireless communication method according to the third embodiment. It is a block diagram in Embodiment 4 of the radio | wireless apparatus shown in FIG. It is a conceptual diagram for demonstrating the method of estimating an extrapolation maximum value. 6 is a flowchart illustrating a wireless communication method according to a fourth embodiment. It is a flowchart for demonstrating the detailed operation | movement of step S33 of FIG.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. With reference to FIG. 1, a wireless communication system 10 includes wireless devices 1 to 5. The wireless devices 1 to 5 are arranged in a wireless communication space. More specifically, the wireless devices 1 to 5 are arranged in an area REG in which the wireless devices 1 to 5 can directly wirelessly communicate with each other. Each of the wireless devices 1 to 5 determines whether or not wireless communication is possible by a method described later when another wireless device other than itself is performing wireless communication, and wireless communication is possible. When it is determined that there is, wireless communication is performed using one frequency band.

[Embodiment 1]
FIG. 2 is a configuration diagram of Embodiment 1 of wireless device 1 shown in FIG. With reference to FIG. 2, the wireless device 1 includes an antenna 11, a transmission / reception unit 12, a communication unit 13, a determination unit 14, and a calculation unit 15.

  The antenna 11 receives a packet from another wireless device via the wireless communication space, and outputs the received packet to the transmission / reception means 12.

  The antenna 11 receives a packet from the transmission / reception means 12 and transmits the received packet to another wireless device via the wireless communication space.

The transmission / reception means 12 measures the interference power I _js obtained when the antenna 11 receives the probe signal PRBj in the signal channel. The signal channel is provided for transmitting and receiving the probe signal PRBj on the link j.

The transmission / reception means 12 measures the interference power I _jd obtained when the antenna 11 receives a packet including normal data in the data channel.

The transmission / reception means 12 outputs the measured interference powers I _js and I _jd to the communication means 13.

The transmission / reception means 12 receives a packet from the antenna 11. Transceiver means 12, the interference power _I js packet at the transmission _destination, when containing _{I jd,} taken interference power _{I js,} the _{I jd} from the packet. Then, the transmission / reception unit 12 outputs the extracted interference powers I _js and I _jd to the calculation unit 15.

  On the other hand, the transmission / reception unit 12 outputs the packet to the communication unit 13 when the packet includes normal data.

Further, the transmission / reception unit 12 receives the transmission power σ _jd = SINR ^T _j × I _jd and σ _js = α × SINR ^T _j × I _js from the calculation unit 15. The constant σ is greater than 0 and 1 or less. The constant σ is determined in advance in the wireless communication system 10.

Further, the transmission / reception unit 12 receives a packet including the interference powers I _js and I _jd from the communication unit 13. The transmission / reception means 12 transmits the received packet to the transmission source via the antenna 11.

Further, the transmission / reception means 12 receives Kmax (Kmax is 3 or more) probe signals from the communication means 13. Then, the transmission / reception means 12 transmits the received Kmax probe signals to the transmission destination at different timings with transmission power σ _js = α × SINR ^T _j × I _js in a signal channel having a frequency in the frequency band BW0. .

Further, the transmission / reception unit 12 receives a packet including normal data from the communication unit 3. When the transmission / reception means 12 receives the signal COK indicating that wireless communication is possible from the determination means 14, the transmission power σ _jd = SINR ^T _j × I _jd in the data channel having the frequency in the frequency band BW1 A packet containing the data is transmitted to the transmission destination. The frequency band BW1 is different from the frequency band BW0.

The communication unit 13 receives the interference powers I _js and I _jd from the transmission / reception unit 12.
The communication unit 13 generates a packet including the interference powers I _js and I _jd in the data part, and outputs the generated packet to the transmission / reception unit 12.

  Further, when receiving the signal COK from the determination unit 14, the communication unit 13 generates a packet including normal data in the data portion, and outputs the generated packet to the transmission / reception unit 12.

  Further, the communication means 13 generates Kmax probe signals PRBj (1) to PRBj (Kmax) and outputs the generated Kmax probe signals PRBj (1) to PRBj (Kmax) to the transmission / reception means 12.

The determination unit 14 receives Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) | from the calculation unit 15. Then, the determination unit 14 determines whether or not the evaluation item | W _j (Kmax, t) | is smaller than 1.

When it is determined that the evaluation item | W _j (Kmax, t) | is smaller than 1, the determination unit 14 generates a signal COK and outputs the generated signal COK to the transmission / reception unit 12 and the communication unit 13.

On the other hand, the determination means 14 does not generate a signal when it is determined that the evaluation item | W _j (Kmax, t) | is 1 or more.

The calculating means 15 holds a constant α and a target signal-to-noise interference ratio SINR ^T _j . The calculation means 15 receives the interference powers I _js and I _jd from the transmission / reception means 12. The computing means 15 computes transmission power σ _jd = SINR ^T _j × I _jd , σ _js = α × SINR ^T _j × I _js, and the computed transmission power σ _jd = SINR ^T _j × I _jd , σ _js = α × SINR ^T _j × I _js is output to the transmission / reception means 12.

Every time the calculation means 15 receives the interference power I _js , the calculation means 15 calculates the evaluation item | W _j (k, t) | Then, the calculation means 15 outputs the calculated evaluation item | W _j (k, t) | to the determination means 14.

  Note that each of the wireless devices 2 to 5 illustrated in FIG. 1 has the same configuration as the wireless device 1 illustrated in FIG. 2.

  FIGS. 3 to 6 show first to fourth examples of evaluation functions determined for each service quality. 3 to 6, the vertical axis represents transmission power, and the horizontal axis represents interference power.

Referring to FIG. 3, a curve k1 indicates the interference power dependency of transmission power σ _js in a mobile phone, for example. The transmission power σ _js holds a constant value with respect to the interference power when the interference power is smaller than the reference value I _th1 . When the interference power is greater than or equal to the reference value I _th1 , the transmission power σ _js decreases according to a downwardly convex curve with respect to the increase in interference power, and becomes a substantially constant value.

  Since the mobile phone is used by many users, it is assumed that when a certain user performs wireless communication using the mobile phone, another user has already performed wireless communication using the mobile phone.

  In such a case, a mobile phone of a certain user receives interference from the mobile phone of another user. If the required transmission power increases as the interference power increases, the transmission power required by each mobile phone further increases, making it difficult to perform wireless communication.

Therefore, the transmission power σ _js is changed with respect to the interference power as shown by the curve k1.

Therefore, the interference power dependence of the transmission power σ _js indicated by the curve k1 is generally used when many users perform radio communication simultaneously.

With reference to FIG. 4, a curve k <b> 2 indicates, for example, the interference power dependence of the transmission power σ _js in a wireless device installed in the vehicle. When the transmission power σ _js is lower than the upper limit value σ _Limit , the transmission power σ _js increases according to an upwardly convex curve with respect to the increase in interference power and becomes a substantially constant value.

  When the wireless device is mounted on a vehicle, it is necessary to transmit information to a transmission destination as quickly as possible.

Therefore, in order to ensure a high transmission rate even when the interference power increases, the transmission power σ _js is increased with respect to the interference power as shown by the curve k2.

Referring to FIG. 5, a curve k3 indicates the interference power dependence of transmission power σ _js in a wireless device that transmits packets at a constant transmission rate, for example. The transmission power σ _js increases linearly with an increase in interference power when the interference power is smaller than the reference value I _th2 . When the interference power is greater than or equal to the reference value I _th2 , the transmission power σ _js increases according to a curve convex upward with respect to the interference power.

  In order to keep the transmission rate constant in a wireless communication environment where interference power exists, it is necessary to increase the transmission power with respect to an increase in interference power.

Therefore, when the interference power is smaller than the reference value _Ith2 , the transmission power σ _js is linearly increased with respect to the increase of the interference power. When the interference power is greater than or equal to the reference value I _th2 , the transmission power σ _js is determined to increase nonlinearly with respect to the increase in interference power in consideration of the upper limit value σ _Limit of the transmission power σ _js .

Referring to FIG. 6, a curve k4 indicates the interference power dependence of the transmission power σ _js in, for example, a wireless device that uses a predetermined range of transmission power. The transmission power σ _js changes in a range from the transmission power σ 1 to the transmission power σ 2 with respect to an increase in interference power. More specifically, the transmit power sigma _js, when the interference power is less than the reference value I _th3, increases according to curve upwardly convex from the transmit power σ1 relative increase in interference power. The transmission power σ _js is substantially constant with respect to the increase in interference power when the interference power is in the range from the reference value I _th3 to the reference value I _th4 . The transmission power σ _js increases to the transmission power σ 2 according to a downwardly convex curve when the interference power is equal to _or greater than the reference value I _th4 .

When the transmission power σ _js is set in a predetermined range, when the interference power is in the range from the reference value I _th3 to the reference value I _th4 , the transmission power σ _js is set to an average value of the transmission power σ1 and the transmission power σ2. A close value may be set. However, it is necessary to reduce the influence of the interference power on the transmission power σ _{js in} the range where the interference power is less than or equal to the reference value I _th3 or in the range greater than or equal to the reference value I _th4 .

Therefore, the transmission power σ _js is increased with respect to the interference power as shown by the curve k4.

  Note that, in each of the wireless devices 1 to 5, the computing unit 15 maintains the curve k1 in association with the service quality that many users simultaneously perform wireless communication, and supports the service quality that ensures a high transmission rate. In addition, the curve k2 is held, the curve k3 is held in association with the service quality of holding a constant transmission rate, and the curve k4 is held in association with the service quality of using a predetermined range of transmission power.

The signal-to-noise interference ratio SINR represents the overall quality of service. In this embodiment, the link represents the required or preferred QoS by defining the target SINR as a function of interference. For practical purposes, the link uses an equivalent function that defines the dependence of transmit power on interference. Accordingly, each of the curves k1 to k4 constitutes the evaluation function β _j (I _j ). The transmission power σ _{js at} the transmitter of link j is assigned by σ _js = β _j (I _j ).

The calculation method of the evaluation item | W _j (k, t) | is shown below. The evaluation function β _j (I _j ) is defined by b _j + a _j * I _j . Each of the parameters b _j and a _j is a parameter for defining the evaluation function β _j (I _j ).

When receiving the interference power I _js from the transmission / reception unit 12, the calculation unit 15 refers to any one of the curves k1 to k4 and calculates the value of the evaluation function β _j (I _j ) corresponding to the received interference power I _js. To detect. Then, the calculation means 15 determines the parameters b _j and a _j so that the detected value becomes equal to b _j + a _j * I _j .

Thereafter, the calculation means 15 calculates the transmission power σ _js ( _kt ) = SINR ^T _j × I _js using the interference power I _js and the target signal-to-noise interference ratio SINR ^T _j . Note that k (1 ≦ k ≦ Kmax) represents the number of times, and t represents a delay (> 0).

In addition, the computing unit 15 uses the following formula based on the transmission power σ _js (k−t), the parameter a _j , and the interference power I _js (k) to evaluate the evaluation item | W _j (k, t) | Is calculated.
[Formula 1]
| W _j (k, t) | = | a _j I _js (k) σ _js ( _kt ) | (1)

  FIG. 7 is a conceptual diagram of a frequency band. Referring to FIG. 7, frequency band BW0 is provided for transmitting and receiving probe signal PRBj. The frequency band BW1 is provided for transmitting and receiving packets including normal data.

When each of the wireless devices 1 to 5 starts wireless communication with the transmission destination, the wireless devices 1 to 5 transmit the probe signal PRBj to the transmission destination with transmission power σ _js = α × SINR ^T _j × I _js in the signal channel of the frequency band BW0. To do.

FIG. 8 is a conceptual diagram for explaining the radio communication method according to the first embodiment. Referring to FIG. 8, radio apparatus 2 transmits probe signal PRBj to radio apparatus 1 via link ML1 in the signal channel of frequency band BW0. The wireless device 2 transmits a packet including normal data to the wireless device 1 through the link ML1 in the data channel of the frequency band BW1. When the wireless device 1 receives the probe signal PRBj in the signal channel, the wireless device 1 measures the interference power I _1s . In addition, when the wireless device 1 receives a packet including normal data in the data channel, the wireless device 1 measures the interference power I _1d . Then, the wireless device 1 transmits the interference powers I _1s and I _1d to the wireless device 2.

The wireless device 2 receives the interference powers I _1s and I _1d from the wireless device 1. Then, the wireless device 2 calculates transmission power σ _1d = α × SINR ^T ₁ × I _1d using the interference power I _1d, and uses the interference power I _1s to transmit power σ _1s = α × SINR ^T _{1. XI 1s} is calculated. Accordingly, the wireless device 2 transmits a packet including normal data with the transmission power σ _1d = SINR ^T ₁ × I _1d in the data channel on the link ML1 as the active link. In addition, the wireless device 2 transmits the probe signal PRBj with the transmission power σ _1s = α × SINR ^T ₁ × I _1s in the signal channel on the link ML1 as an active link.

The wireless device 4 transmits the probe signal PRBj with the transmission power σ _2s = α × SINR ^T ₂ × I _2s in the signal channel and the transmission power σ _1d = SINR in the data channel on the link ML2 by the same method as the wireless device 2. A packet including normal data is transmitted at ^T ₁ × I _1d .

  In this situation, the wireless device 5 starts wireless communication with the wireless device 3 through the link ML3 in the data channel of the frequency band BW1. In this case, the wireless device 3 is a transmission destination, and the wireless device 5 is a transmission source.

The wireless device 5 that is the transmission source transmits the probe signal PRBj (k) to the wireless device 3 that is the transmission destination with transmission power σ _js = α × SINR ^T _j × I _js (k−1) in the signal channel of the frequency band BW0. Send. The wireless device 3 that is the transmission destination receives interference powers I1 and I2 from the wireless devices 2 and 4 when the wireless device 3 receives the probe signal PRBj (k) from the wireless device 5 in the signal channel.

The transmission power σ ₀ is used when each of the radio apparatuses 1 to 5 transmits Kmax probe signals PRBj (1) to PRBj (Kmax) for the first time. The transmission power σ ₀ is determined in advance in the wireless communication system 10, and each of the wireless devices 1 to 5 holds the transmission power σ ₀ .

The transmission / reception means 12 of the wireless device 3 measures the interference power I _js (k) obtained when the antenna 11 receives the probe signal PRBj (k) from the wireless device 5. The transmission / reception unit 12 of the wireless device 3 outputs the measured interference power I _js (k) to the communication unit 13.

The communication unit 13 of the wireless device 3 receives the interference power I _js (k) from the transmission / reception unit 12. Then, the communication unit 13 of the wireless device 3 generates a packet PKT1 = [Add5 / I _js (k)] including the interference power I _js (k) and the address Add5 of the wireless device 5, and the generated packet PKT1 = [Add5 / I _js (k)] is output to the transmission / reception means 12.

Wireless device 3 of the transmitting and receiving unit 12 receives a packet _{PKT1 = [Add5 / I js (} k)] from the communication unit 13, wireless device packet _{PKT1 = [Add5 / I js (} k)] in the signal channel of the frequency band BW0 To 5.

The transmission / reception means 12 of the wireless device 5 receives the packet PKT1 = [Add5 / I _js (k)] via the antenna 11 in the signal channel of the frequency band BW0. Then, the transmission / reception means 12 of the wireless device 5 extracts the interference power I _js (k) from the packet PKT1. The transmission / reception means 12 of the wireless device 5 outputs the extracted interference power I _js (k) to the calculation means 15.

When receiving the interference power I _js (k) from the transmission / reception unit 12, the calculation unit 15 of the wireless device 5 transmits transmission power σ _js (k−t) = SINR ^T _j × I _js (k), σ _jd (k−t ) = SINR ^T _j × I _jd (k) is calculated, and the calculated transmission σ _js ( _kt ) = SINR ^T _j × I _js (k), σ _jd ( _kt ) = SINR ^T _j × I _jd (k) is output to the transmission / reception means 12.

Further, the computing means 15 of the wireless device 5 computes the evaluation item | W _j (k, t) | using Expression (1), and determines the computed evaluation item | W _j (k, t) | 14 to output.

Upon receiving Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) | from the calculation unit 15, the determination unit 14 of the wireless device 5 receives the evaluation items | W _j (Kmax, t ) | Is smaller than 1. When it is determined that the evaluation item | W _j (Kmax, t) | is smaller than 1, the determination unit 14 of the wireless device 5 generates a COK signal and transmits the generated COK signal to the transmission / reception unit 12 and the communication unit 13. Output.

  Upon receiving the COK signal from the determination unit 14, the communication unit 13 of the wireless device 5 generates a packet PKT2 = [Add3 / Data] including normal data and the address Add3 of the wireless device 3 that is the transmission destination. The generated packet PKT2 = [Add3 / Data] is output to the transmission / reception means 12.

The transmission / reception means 12 of the wireless device 5 sends the transmission power σ _js ( _kt ) = SINR ^T _j × I _js (k), σ _jd ( _kt ) = SINR ^T _j × I _jd (k) from the calculation means 15. And the packet PKT2 = [Add3 / Data] is received from the communication means 13. Receiving means of the wireless device 5 12, when the determination means 14 receives the COK signal, power sigma _jd in the data channel of the transmission frequency band BW1 (k-t) = SINR T j × packets _I jd (k) PKT2 = [ Add3 / Data] is transmitted to the wireless device 3.

  The transmission / reception means 12 of the wireless device 3 receives the packet PKT2 = [Add3 / Data] in the data channel of the frequency band BW1, and outputs the packet PKT2 = [Add3 / Data] to the communication means 13. Then, the communication unit 13 of the wireless device 3 receives the packet PKT2 = [Add3 / Data].

When it is determined that the evaluation item | W _j (Kmax, t) | is 1 or more, the determination unit 14 of the wireless device 5 does not generate a signal. Therefore, the communication unit 13 of the wireless device 5 transmits the packet PKT2 = [Add3 / Data] is not generated, and the transmission / reception means 12 of the wireless device 5 does not transmit the packet PKT2 = [Add3 / Data]. In this case, when the communication unit 13 of the wireless device 5 transmits Kmax probe signals PRBj (1) to PRBj (Kmax) and does not receive the COK signal from the determination unit 14 during a predetermined period, The probe signals PRBj (1) to PRBj (Kmax) are generated again, and the generated Kmax probe signals PRBj (1) to PRBj (Kmax) are output to the transmission / reception means 12. Then, the transmitting / receiving unit 12 of the wireless device 5 transmits Kmax probe signals PRBj (1) to PRBj (Kmax) received from the communication unit 13. Thereafter, the wireless device 5 determines whether or not wireless communication is possible by the above-described method, and when determining that wireless communication is possible, the wireless device 5 transmits a packet including normal data to the wireless device 3 that is a transmission destination. Send.

FIG. 9 is a flowchart illustrating the wireless communication method according to the first embodiment. Referring to FIG. 9, when a series of operations is started, the transmission source sets k = 1 (step S1), and transmission power σ _js = α × SINR ^T _j × I in the signal channel of frequency band BW0. _The probe signal PRBj (k) is transmitted with _js (k−1) or σ ₀ (step S2).

The transmission destination measures the interference power I _js (k) obtained when the antenna 11 receives the probe signal PRBj (k) in the signal channel from the transmission source (step S3). Destination, generated the measured interference power _I js (k) packets containing _{PKT1 = [I js (k)} ] , and transmits the generated packet _{PKT1 = [I js (k)} ] to the sender ( Step S4).

The transmission source receives the packet PKT1 = [I _js (k)] from the transmission destination (step S5). The transmission source extracts the interference power I _js (k) from the packet PKT1. The transmission source calculates transmission power σ _js (k) = α × SINR ^T _j × I _js (k) (step S6). Further, the transmission source calculates the evaluation item | W _j (k, t) | by the above-described method (step S7).

  The transmission source determines whether k is equal to Kmax (step S8). When it is determined in step S8 that k is not equal to Kmax, the transmission source sets k = k + 1 (step S9). Thereafter, the series of operations returns to step S2, and steps S2 to S9 are repeatedly executed until it is determined in step S8 that k is equal to Kmax.

On the other hand, when it is determined in step S8 that k is equal to Kmax, the transmission source further determines whether or not the evaluation item | W _j (Kmax, t) | is smaller than 1 (step 10).

When it is determined in step 10 that the evaluation item | W _j (Kmax, t) | is smaller than 1, the transmission source generates a packet PKT2 = [Data] including normal data, and data in the frequency band BW1 In the channel, the packet PKT2 = [Data] is transmitted to the transmission destination with the transmission power σ _jd (k) (step S11). Note that the source, transmission power ^{_{σ jd (k) = SINR T}} j × I jd (k) of calculating, for holding the transmission power ^{_{σ jd (k) = SINR T}} j × I jd and (k). The transmission destination receives the packet PKT2 = [Data] in the data channel of the frequency band BW1 (step S12).

When it is determined in step S10 that the evaluation item | W _j (Kmax, t) | is 1 or more, or after step S12, the series of operations ends.

  In addition, the transmission source transmits a packet including normal data to the transmission destination by repeatedly executing steps S1 to S12.

As described above, when it is determined that the evaluation item | W _j (Kmax, t) | is smaller than 1, the transmission source determines that wireless communication is possible, and packet PKT2 = [ Data] is transmitted (see “YES” in step S10 and step S11). The reason is as follows. Each of the evaluation items | W _j (1, t) | to | W _j (Kmax, t) | is calculated using Expression (1). Therefore, each of the evaluation items | W _j (1, t) | to | W _j (Kmax, t) | is proportional to the interference power I _js (k) measured by the transmission destination. As a result, when the evaluation item | W _j (Kmax, t) | is smaller than 1, the interference power I _js (k) of the transmission destination is constant if the transmission power of the transmission source is constant. If the interference power I _js (k) at the transmission destination becomes constant, the wireless communication space becomes stable. Therefore, when it is determined that the evaluation item | W _j (Kmax, t) | is smaller than 1, it is determined that wireless communication is possible.

As described above, the transmission source calculates Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) |, and the evaluation item | W _j (Kmax, t) | When it is determined that the wireless communication is smaller than that, it is determined that wireless communication is possible. Therefore, the transmission source can easily determine whether or not wireless communication is possible.

Furthermore, when the transmission source receives the interference power I _js (k), the transmission source calculates transmission power σ _js (k) = α × SINR ^T _j × I _js (k). Therefore, the time for determining the transmission power σ _js (k) = α × SINR ^T _j × I _js (k) can be shortened.

[Embodiment 2]
FIG. 10 is a configuration diagram of the radio apparatuses 1 to 5 shown in FIG. 1 according to the second embodiment. In the second embodiment, each of wireless devices 1 to 5 includes wireless device 1A shown in FIG.

  Referring to FIG. 10, radio apparatus 1A is obtained by replacing determination means 14 and calculation means 15 of radio apparatus 1 shown in FIG. 2 with determination means 14A and calculation means 15A, respectively. Same as 1.

The determination unit 14A receives Kmax evaluation items | W _j (1, t) | / α to | W _j (Kmax, t) | / α from the calculation unit 15A. Then, the determination unit 14A determines whether or not the evaluation item | W _j (Kmax, t) | / α is smaller than 1. When it is determined that the evaluation item | W _j (Kmax, t) | / α is smaller than 1, the determination unit 14A generates the signal COK and outputs the generated signal COK to the transmission / reception unit 12 and the communication unit 13. To do. On the other hand, when it is determined that the evaluation item | W _j (Kmax, t) | / α is 1 or more, the determination unit 14A does not generate a signal.

  Regarding the other functions, the determination unit 14 </ b> A performs the same function as the determination unit 14.

When receiving the interference power I _js (k) from the transmission / reception unit 12, the calculation unit 15A calculates the evaluation item | W _j (k, t) | by the method described above. The computing means 15A is evaluation item _{| W j (k, t)} | computes / alpha, evaluation items _{| W j (k, t)} | / α and outputs to the determining means 14A.

  For other functions, the calculation means 15A performs the same function as the calculation means 15.

  FIG. 11 is a flowchart illustrating a wireless communication method according to the second embodiment. The flowchart shown in FIG. 11 is obtained by replacing step S7 of the flowchart shown in FIG. 9 with step S7A, and the other parts are the same as the flowchart shown in FIG.

Referring to FIG. 11, when a series of operations is started, steps S1 to S6 are executed as described above. After step S6, the transmission source calculates the evaluation item | W _j (k, t) | / α (step S7A). Then, Steps S8 to S12 are executed as described above.

  In addition, the transmission source transmits a packet including normal data to the transmission destination by repeatedly executing steps S1 to S6, S7A, and S8 to S12.

As described above, the transmission source calculates Kmax evaluation items | W _j (1, t) | / α to | W _j (Kmax, t) | / α to evaluate the evaluation items | W _j (Kmax, t ) When it is determined that | / α is smaller than 1, it is determined that wireless communication is possible. Therefore, the transmission source can easily determine whether or not wireless communication is possible.

  Other explanations in the second embodiment are the same as those in the first embodiment.

[Embodiment 3]
FIG. 12 is a configuration diagram of the wireless devices 1 to 5 shown in FIG. 1 according to the third embodiment. In the third embodiment, each of wireless devices 1 to 5 includes wireless device 1B shown in FIG.

  Referring to FIG. 12, radio apparatus 1B is obtained by replacing determination means 14 and calculation means 15 of radio apparatus 1 shown in FIG. 2 with determination means 14B and calculation means 15B, respectively. Same as 1.

  The determination unit 14B receives the extrapolated value L from the calculation unit 15B. Then, the determination unit 14B determines whether or not the extrapolated value L is smaller than 1. When it is determined that the extrapolation value L is smaller than 1, the determination unit 14B generates a signal COK and outputs the generated signal COK to the transmission / reception unit 12 and the communication unit 13. On the other hand, when the determination unit 14B determines that the extrapolation value L is 1 or more, it does not generate a signal.

  The determination unit 14B performs the same function as the determination unit 14 for other functions.

When receiving the interference power I _js (k) from the transmission / reception unit 12, the calculation unit 15B calculates the evaluation item | W _j (k, t) | by the method described above. When the calculation means 15B completes the calculation of Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) |, the Kmax evaluation items | W _j (1 , T) | to | W _j (Kmax, t) | are extrapolated to obtain an extrapolated value L. And the calculating means 15B outputs the extrapolation value L to the determination means 14B.

  The calculation means 15B performs the same function as the calculation means 15 with respect to other functions.

FIG. 13 is a conceptual diagram for explaining a method of determining the extrapolation value L. In FIG. 13, the vertical axis represents the evaluation item | W _j (k, t) |, and the horizontal axis represents time. A curve k5 represents an exponential function. FIG. 13 shows a case where four evaluation items | W _j (1, t) | to | W _j (4, t) |

Referring to FIG. 13, in each of wireless devices 1 to 5 (= 1B) that are transmission sources, calculation means 15B includes, for example, four evaluation items | W _j (1, t) | to | W _j ( 4, t) | Then, the computing means 15B, for example, uses four exponential items | W _j (1, t) | to | W _j (4, t) using an exponential function (= k5) of a × (t) ^1/2. Extrapolate |. Note that a is a constant.

  As a result, the computing means 15B obtains a value that makes the exponential function (= k5) constant as the extrapolated value L.

  FIG. 14 is a flowchart illustrating a wireless communication method according to the third embodiment. The flowchart shown in FIG. 14 is obtained by replacing step S10 of the flowchart shown in FIG. 9 with steps S10A and S10B, and the other parts are the same as the flowchart shown in FIG.

Referring to FIG. 14, when a series of operations is started, steps S1 to S9 are executed as described above. If it is determined in step S8 that k is equal to Kmax, the transmission source extrapolates Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) | L is obtained (step S10A). Then, the transmission source determines whether or not the extrapolation value L is smaller than 1 (step S10B).

  When it is determined in step S10B that the extrapolation value L is smaller than 1, steps S11 and S12 are executed as described above.

  On the other hand, when it is determined in step S10B that the extrapolation value L is 1 or more, the series of operations ends.

  Note that the transmission source transmits a packet including normal data to the transmission destination by repeatedly executing steps S1 to S9, S10A, S10B, S11, and S12.

As described above, when it is determined that the extrapolation value L is smaller than 1, the transmission source transmits the packet PKT2 = [Data] to the transmission destination (see “YES” in step S10B and step S11). The reason is as follows. When the extrapolated value L is smaller than 1, the interference power I _js (k) is smaller than the transmission power σ _js (k). As a result, the transmission destination can stably receive the packet PKT2 = [Data] including normal data. Therefore, when the extrapolated value L is smaller than 1, it is determined that wireless communication is possible.

In the third embodiment, the transmission source calculates Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) | to obtain Kmax evaluation items | W _j (1, t) | to | W _j (Kmax, t) | are extrapolated to obtain an extrapolated value L, and the extrapolated value L is used to determine whether wireless communication is possible. Therefore, energy for determining whether or not wireless communication is possible can be reduced.

  Other explanations in the third embodiment are the same as those in the first embodiment.

[Embodiment 4]
FIG. 15 is a configuration diagram of Embodiment 4 of the wireless devices 1 to 5 shown in FIG. In the fourth embodiment, each of wireless devices 1 to 5 includes wireless device 1C shown in FIG.

  Referring to FIG. 15, radio apparatus 1C includes transmission / reception means 12, communication means 13, determination means 14 and calculation means 15 of radio apparatus 1 shown in FIG. 2 as transmission / reception means 12A, communication means 13A, determination means 14C, and calculation. Instead of the means 15C, the other parts are the same as those of the wireless device 1.

The transmission / reception unit 12A receives m (m is 2 or more) transmission powers σ _{01 to} σ _0m from the calculation unit 15C. For example, m transmission powers σ _{01 to} σ _0m are 0.1 × σ _js , 0.2 × σ _js , and 0.3 × σ _js , respectively.

When transmitting / receiving means 12A receives Kmax probe signals PRBj (1) to PRBj (Kmax) from communication means 13A, Kmax probe signals PRBj at each of transmission powers σ _{01 to} σ _0m in the signal channel of frequency band BW0. (1) to PRBj (Kmax) are transmitted to the transmission destination.

The transmission / reception unit 12A of the transmission destination receives Kmax interference powers I _j (1) obtained when the antenna 11 receives Kmax probe signals PRBj (1) to PRBj (Kmax) transmitted at the transmission power σ _01. ^{1 to} I _j (Kmax) ¹ is measured. Further, the transmission / reception means 12A as the transmission destination receives Kmax interference powers I _j (when the antenna 11 receives Kmax probe signals PRBj (1) to PRBj (Kmax) transmitted at the transmission power σ _02. 1) ^{2 to} I _j (Kmax) ² are measured. Similarly, the transmission / reception means 12A of the transmission destination receives Kmax interference powers I obtained when the antenna 11 receives Kmax probe signals PRBj (1) to PRBj (Kmax) transmitted at the transmission power σ _{0m. j} (1) ^{m to} I _j (Kmax) ^m are measured. Then, the transmission / reception means 12A transmits the interference powers I _j (1) ^{1 to} I _j (Kmax) ¹ , I _j (1) ^{2 to} I _j (Kmax) ² ,..., I _j (1) ^{m to} I _j (Kmax) ^m is output to the communication means 13A.

The transmission / reception means 12A of the transmission destination includes m groups G1 = [I _j (1) ^{1 to} I _j (Kmax) ¹ ], G2 = [I _j (1) ^{2 to} I _j (Kmax) ² ],. The packet PKT1 = [G1 / G2 /... / Gm] including Gm = [I _j (1) ^{m to} I _j (Kmax) ^m ] is received from the communication unit 13A. Then, the transmission / reception means 12A as the transmission destination transmits the packet PKT1 = [G1 / G2 /... / Gm] to the transmission source in the signal channel of the frequency band BW0.

  The transmission / reception means 12A of the transmission source receives the packet PKT1 = [G1 / G2 /... / Gm] from the transmission destination via the antenna 11 in the signal channel of the frequency band BW0. The transmission / reception unit 12A of the transmission source extracts m groups G1 to Gm from the packet PKT1, and outputs the extracted m groups G1 to Gm to the calculation unit 15C.

  The transmitting / receiving unit 12A performs the same function as the transmitting / receiving unit 12 with respect to other functions.

  The communication unit 13A receives m groups G1 to Gm from the transmission / reception unit 12A. Then, the communication means 13A generates a packet PKT1 = [G1 / G2 /... / Gm] and outputs the packet PKT1 = [G1 / G2 /... / Gm] to the transmission / reception means 12A.

  The communication unit 13A performs the same function as the communication unit 13 with respect to other functions.

The determination unit 14C receives the extrapolation maximum value L _MAX from the calculation unit 15C. Then, the determination unit 14 </ b> C determines whether or not the extrapolation maximum value L _MAX is smaller than 1. When it is determined that the extrapolation maximum value L _MAX is smaller than 1, the determination unit 14C generates a signal COK and outputs the generated signal COK to the transmission / reception unit 12A and the communication unit 13A.

Calculation means 15C is a constant value _{c 1,} c 2 to transmit power sigma _js, · · ·, m-number of transmission power sigma ₀₁ by multiplying the _{c m,} σ _02, ···, calculates the sigma _{0 m.} Each constant value _{c 1, c 2, ···,} c m is greater than 0, and smaller than 0.5. Then, the calculation means 15C outputs the calculated transmission powers σ ₀₁ , σ ₀₂ ,..., Σ _0m to the transmission / reception means 12A.

The calculation means 15C receives m groups G1 to Gm from the transmission / reception means 12A. Based on the group G1, the calculation unit 15C calculates Kmax transmission powers σ ₁₁ = SINR ^T _j × I _js (1) ¹ , σ ₁₂ = SINR ^T _j × I _js (2) ¹ ,..., Σ _1Kmax = SINR ^T _j × I _js (Kmax) ¹ is calculated. Further, the computing means 15C, based on the group G2, transmits Kmax transmission powers σ ₂₁ = SINR ^T _j × I _js (1) ² , σ ₂₂ = SINR ^T _j × I _js (2) ² _,. σ _2Kmax = SINR ^T _j × I _js (Kmax) ² is calculated. Similarly, the calculation unit 15C determines that Kmax transmission powers σ _m1 = SINR ^T _j × I _js (1) ^m , σ _m2 = SINR ^T _j × I _js (2) ^m ,. , Σ _mKmax = SINR ^T _j × I _js (Kmax) ^m is calculated.

The computing means 15C substitutes the parameter a _j , Kmax transmission powers σ _{11 to} σ _1Kmax and Kmax interference powers I _js (1) ^{1 to} I _js (Kmax) ¹ into the equation (1). Evaluation items | W ₁₁ (k, t) |, | W ₁₂ (k, t) |,..., | W _1Kmax (Kmax, t) | Further, the calculation means 15C substitutes the parameter a _j , Kmax transmission powers σ _{21 to} σ _2Kmax and Kmax interference powers I _js (1) ^{2 to} I _js (Kmax) ² into the equation (1). , Kmax evaluation items | W ₂₁ (k, t) |, | W ₂₂ (k, t) |,..., | W _2Kmax (Kmax, t) | Similarly, the calculation means 15C substitutes the parameter a _j , Kmax transmission powers σ _{m1 to} σ _mKmax and Kmax interference powers I _js (1) ^{m to} I _js (Kmax) ^m into the equation (1). Thus, Kmax evaluation items | W _m1 (k, t) |, | W _m2 (k, t) |,..., | W _mKmax (Kmax, t) |

Thereafter, the calculation means 15C extrapolates Kmax evaluation items | W ₁₁ (k, t) |, | W ₁₂ (k, t) |,..., | W _1Kmax (Kmax, t) | An insertion value L1 is obtained. The computing means 15C extrapolates Kmax evaluation items | W ₂₁ (k, t) |, | W ₂₂ (k, t) |,..., | W _2Kmax (Kmax, t) | An insertion value L2 is obtained. Similarly, the calculation means 15C extrapolates Kmax evaluation items | W _m1 (k, t) |, | W _m2 (k, t) |,..., | W _mKmax (Kmax, t) | To obtain an extrapolated value Lm.

Furthermore, the calculating means 15C is extrapolated when interference target of the signal-to-noise-and-interference ratio SINR ^T _j power _I js (k) multiplied to the resultant transmit power sigma _js (k) is used, the outer挿最Univ Estimate the value L _MAX . Then, the calculation means 15C outputs the extrapolation maximum value L _MAX to the determination means 14C.

  The calculation means 15C performs the same function as the calculation means 15 with respect to other functions.

FIG. 16 is a conceptual diagram for explaining a method for estimating the extrapolation maximum value L _MAX . In FIG. 16, the vertical axis represents an extrapolated value, and the horizontal axis represents c × SINR. c is c ₁ , c ₂ ,..., _cm . FIG. 16 shows a case where three extrapolated values L1 to L3 are extrapolated.

Referring to FIG. 16, in each of wireless devices 1 to 5 as a transmission source, calculation means 15C performs evaluation items | W ₁₁ (k, t) |, | W ₁₂ (k, t) by the method described above. |, ..., | W _1Kmax (Kmax, t) |, | W ₂₁ (k, t) |, | W ₂₂ (k, t) |, ..., | W _2Kmax (Kmax, t) |, | W ₃₁ (k, t) |, | W ₃₂ (k, t) |,..., | W _3Kmax (Kmax, t) | are extrapolated to obtain extrapolated values _{L1 to L3} . Extrapolated values L1-L3 are extrapolated when 0.1 × SINR, 0.2 × SINR, and 0.3 × SINR are used, respectively.

And the calculation means 15C calculates the straight line k6 based on the extrapolation values L1-L3. Thereafter, the calculation means 15C estimates the extrapolated maximum value L _MAX extrapolated when 1.0 × SINR is used, based on the straight line k6.

FIG. 17 is a flowchart illustrating a wireless communication method according to the fourth embodiment. Referring to FIG. 17, when a series of operations is started, the transmission source sets p = 1 (step S21) and k = 1 (step S22). The transmission source transmits the probe signal PRBj (k) with the transmission power σ _0p (k) in the signal channel of the frequency band BW0 (step S23).

The transmission destination measures the interference power I _js (k) ^p obtained when the antenna 11 receives the probe signal PRBj (k) from the transmission source via the signal channel (step S24). Destination, generated the measured interference power _I js ^(k) packets containing _{^{p PKT1 = [I js (k}} ) p], the generated packet PKT1 ₌ a _[I js ^{(k) p]} to the sender Transmit (step S25).

The transmission source receives the packet PKT1 = [I _js (k) ^p ] from the transmission destination (step S26). The transmission source extracts the interference power I _js (k) ^p from the packet PKT1. The transmission source calculates transmission power σ _jsp (k) = α × SINR ^T _j × I _js (k) ^p (step S27). Further, the transmission source calculates the evaluation item | W _jp (k, t) | (step S28).

  The transmission source determines whether k is equal to Kmax (step S29). When it is determined in step S29 that k is not equal to Kmax, the transmission source sets k = k + 1 (step S30). Thereafter, the series of operations proceeds to step S23, and steps S23 to S30 are repeatedly executed until it is determined in step S29 that k is equal to Kmax.

  On the other hand, when it is determined in step S29 that k is equal to Kmax, the transmission source further determines whether or not p is equal to m (step S31). When it is determined in step S31 that p is not equal to m, the transmission source sets p = p + 1 (step S32). Thereafter, the series of operations proceeds to step S22, and steps S22 to S32 are repeatedly executed until it is determined in step S31 that p is equal to m.

On the other hand, when it is determined in step S31 that p is equal to m, the transmission source estimates the extrapolation maximum value L _MAX (step S33). The transmission source determines whether or not the extrapolation maximum value L _MAX is smaller than 1 (step S34).

When it is determined in step S34 that the extrapolation maximum value L _MAX is smaller than 1, the transmission source generates a packet PKT2 = [Data] including normal data, and transmits the transmission power σ in the data channel of the frequency band BW1. _The packet PKT2 = [Data] is transmitted to the transmission destination by _jd (k) (step S35). The transmission destination receives the packet PKT2 = [Data] in the data channel of the frequency band BW1 (step S36).

When it is determined in step S34 that the extrapolation maximum value L _MAX is 1 or more, or after step S36, the series of operations ends.

  In addition, the transmission source transmits a packet including normal data to the transmission destination by repeatedly executing steps S21 to S36.

  FIG. 18 is a flowchart for explaining the detailed operation of step S33 shown in FIG.

Referring to FIG. 18, when it is determined in step S31 that p is equal to m, the transmission sources are [I _j (1) ^{1 to} I _j (Kmax) ¹ ], [I _j (1) ² to ^{_{I j (Kmax) 2],}} ···, [I j (1) m ~I j (Kmax) m] transmission power σ ₁₁ ~σ _{1Kmax using, σ 21 ~σ 2Kmax, ···,} σ m1 ˜σ _mKmax is calculated (step S331).

The transmission source is parameter a _j , transmission power σ _{11 to} σ _1Kmax , σ _{21 to} σ _2Kmax ,..., Σ _{m1 to} σ _mKmax , and interference power I _j (1) ^{1 to} I _j (Kmax) ¹ , I _j (1) ^{2 to} I _j (Kmax) ² ,..., I _j (1) ^{m to} I _j (Kmax) ^m is substituted into equation (1) to evaluate the evaluation item | W ₁₁ (1, t) | ~ | W _1Kmax (Kmax, t) |, | W ₂₁ (1, t) | ~ | W _2Kmax (Kmax, t) |, ..., | W _m1 (1, t) | ~ | W _mKmax (Kmax , T) | is calculated (step S332).

The transmission source extrapolates Kmax evaluation items | W ₁₁ (1, t) | to | W _1Kmax (Kmax, t) | to obtain an extrapolated value L1, and obtains Kmax evaluation items | W ₂₁ (1 , T) | ˜ | W _2Kmax (Kmax, t) | is extrapolated to obtain an extrapolated value L2, and similarly, Kmax evaluation items | W _m1 (1, t) | ˜ | W _mKmax (Kmax , T) | is extrapolated to obtain an extrapolated value Lm (step S333).

The transmission source uses the transmission power σ _js (k) obtained by multiplying the target signal-to-noise interference ratio SINR ^T _j by the interference power I _js (k) based on the extrapolated values L1 to Lm. The extrapolated maximum value L _MAX extrapolated at the time is estimated (step S334).

  After step S334, the series of operations proceeds to step S34 in FIG.

  The transmission source repeatedly executes steps S23 to S30 Kmax times, thereby transmitting Kmax probe signals PRBj (1) to PRBj (Kmax) to the transmission destination.

When Steps S22 to S32 are repeatedly executed m times, the transmission source is Kmax probe signals PRBj (1) to PRBj (Kmax) with m transmission powers σ ₀₁ (k) to σ _0m (k). Send.

For example, when m is equal to 3, the transmission powers σ ₀₁ (k), σ ₀₂ (k), and σ ₀₃ (k) are 0.1 × σ _js (k) and 0.2 × σ _js (k), respectively. ), 0.3 × σ _js (k). The transmission power σ _js (k) is a transmission power obtained by multiplying the target signal-to-noise interference ratio SINR ^T _j by the interference power I _js (k).

The interference powers I _js (1) ^{1 to} I _js (Kmax) ¹ are measured when the transmission destination receives the probe signals PRBj (1) to PRBj (Kmax) transmitted at the transmission power σ ₀₁ (k). . Therefore, the evaluation items | W ₁₁ (1, t) | ˜ | W _1Kmax (Kmax, t) | are 0.1 × | W _j (1, t) | ˜0.1 × | W _j (Kmax, t ) |

The interference powers I _js (1) ^{2 to} I _js (Kmax) ² are measured when the transmission destination receives the probe signals PRBj (1) to PRBj (Kmax) transmitted at the transmission power σ ₀₂ (k). . Therefore, the evaluation items | W ₂₁ (1, t) | ˜ | W _2Kmax (Kmax, t) | are 0.2 × | W _j (1, t) | ˜0.2 × | W _j (Kmax, t ) |

Further, the interference powers I _js (1) ^{3 to} I _js (Kmax) ³ are measured when the transmission destination receives the probe signals PRBj (1) to PRBj (Kmax) transmitted with the transmission power σ ₀₃ (k). Is done. Therefore, the evaluation items | W ₃₁ (1, t) | ˜ | W _3Kmax (Kmax, t) | are 0.3 × | W _j (1, t) | ˜0.3 × | W _j (Kmax, t ) |

The extrapolation value L1 is obtained by extrapolating Kmax evaluation items | W ₁₁ (1, t) | to | W _1Kmax (Kmax, t) |, and the extrapolation value L2 is Kmax evaluation items. | W ₂₁ (1, t) | ˜ | W _2Kmax (Kmax, t) | is extrapolated, and the extrapolated value L3 is Kmax evaluation items | W ₃₁ (1, t) | ˜ | It is obtained by extrapolating W _3Kmax (Kmax, t) |.

  Further, the extrapolation maximum value Lmax is estimated using the three extrapolation values L1 to L3.

As a result, the extrapolated maximum value L _MAX is lower than the interference powers I _j (1) to I _j (Kmax), I _js (1) ^{1 to} I _js (Kmax) ¹ , I _js (1) ² to It is estimated using I _js (Kmax) ² , I _js (1) ^{3 to} I _js (Kmax) ³ .

Accordingly, the extrapolated maximum value L _MAX can be estimated using less energy. As a result, energy for determining whether wireless communication is possible can be reduced.

The transmission powers σ ₀₁ (k), σ ₀₂ (k), and σ ₀₃ (k) are 0.1 × σ _j (k), 0.2 × σ _j (k), and 0.3 × σ _j ( It is not limited to k). In Embodiment 4, each of the transmission powers σ ₀₁ (k), σ ₀₂ (k), σ ₀₃ (k) is multiplied by the target signal-to-noise interference ratio SINR ^T _j by the interference power I _js (k). The calculation result may be equal to an arbitrary power in the power range obtained by multiplying the calculation result by a predetermined constant larger than 0 and smaller than 0.5.

The transmission powers σ ₀₁ (k), σ ₀₂ (k), and σ ₀₃ (k) may be increased at an arbitrary rate. The difference between the transmission power σ ₀₁ (k) and the transmission power σ ₀₂ (k) may be the same as or different from the difference between the transmission power σ ₀₂ (k) and the transmission power σ ₀₃ (k). Good.

  Other explanations in the fourth embodiment are the same as those in the first and third embodiments.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless device that can easily determine whether or not wireless communication is possible when receiving interference from another wireless device. In addition, the present invention is applied to a wireless communication network including a wireless device that can easily determine whether wireless communication is possible when receiving interference from another wireless device.

  1 to 5, 1A, 1B, 1C wireless device, 10 wireless communication system, 11 antenna, 12, 12A transmission / reception means, 13, 13A communication means, 14, 14A, 14B, 14C determination means, 15, 15A, 15B, 15C means.

Claims (8)

Transmitting means for performing a first process of transmitting Kmax (Kmax is 3 or more) probe signals at different timings with a first transmission power in a first frequency band;
Receiving means for performing a second process of receiving, from the transmission destination, Kmax interference power obtained when the transmission destination receives the Kmax probe signals;
Dividing the received interference power by the first transmission power, and multiplying the division result by a predetermined parameter to perform a process of calculating an evaluation item for the Kmax interference powers; Calculating means for acquiring Kmax evaluation items;
Determination means for determining whether or not the Kmax-th evaluation item is smaller than 1,
When it is determined that the Kmax-th evaluation item is smaller than 1, the transmission means has a second transmission power larger than the first transmission power in a second frequency band different from the first frequency band. To send a packet containing normal data,
The predetermined parameter is a wireless device that defines an evaluation function of a link between the wireless device and the transmission destination. The first transmission power is obtained by multiplying a target signal-to-noise interference ratio by the interference power, and multiplying the operation result by a predetermined constant larger than 0 and smaller than 1. Value
The calculation means further calculates Kmax new evaluation items by dividing the Kmax evaluation items by the predetermined constant,
The determination means determines whether or not the Kmax-th new evaluation item is smaller than 1,
2. The transmission unit transmits a packet including normal data at the second transmission power in the second frequency band when it is determined that the Kmax-th new evaluation item is smaller than 1. 3. A wireless device according to 1. The computing means further performs a third process of extrapolating the Kmax evaluation items to obtain an extrapolated value,
The determination means determines whether the extrapolated value is 1 or less;
The said transmission means transmits the packet containing the said normal data by the said 2nd transmission power in the said 2nd frequency band, when it determines with the said extrapolation value being 1 or less. Wireless devices. The transmitting means is obtained by multiplying the target signal-to-noise interference ratio by the interference power, and multiplying the operation result by a predetermined constant larger than 0 and smaller than 0.5. In the power range, the first process is performed while changing the first transmission power to m (m is 2 or more) first transmission powers,
The receiving means performs the second processing on the m first transmission powers, and acquires m groups each including Kmax interference powers;
The arithmetic means obtains m extrapolated values by executing the third process on the m groups, and is obtained by multiplying the target signal-to-noise interference ratio by the interference power. Estimate the extrapolated maximum that is extrapolated when transmit power is used,
The determination means determines whether the extrapolation maximum value is smaller than 1,
The said transmission means transmits the packet containing the said normal data with the said 2nd transmission power in the said 2nd frequency band, when it determines with the said extrapolation maximum value being smaller than one. The wireless device described. A first wireless device that measures Kmax interference powers when receiving Kmax (Kmax is 3 or more) probe signals;
A first process of transmitting the Kmax probe signals to the first radio apparatus at different timings with a first transmission power in a first frequency band is performed, and Kmax interference powers are transmitted to the first frequency band. A process of performing a second process of receiving from a wireless device, dividing the received interference power by the first transmission power, and calculating an evaluation item by multiplying the division result by a predetermined parameter; The second frequency band that is different from the first frequency band when the Kmax number of evaluation items are obtained by executing the Kmax interference power and it is determined that the Kmax-th evaluation item is smaller than 1. Transmitting a packet including normal data to the first wireless device at a second transmission power larger than the first transmission power at
The wireless communication system, wherein the predetermined parameter is a parameter that defines an evaluation function of a link between the wireless device and a transmission destination. The first transmission power is obtained by multiplying the target signal-to-noise interference ratio by the interference power, and multiplying the calculation result by a predetermined constant greater than 0 and 1 or less. Value,
The second radio apparatus further calculates Kmax new evaluation items by dividing the Kmax evaluation items by the predetermined constant, and the Kmaxth new evaluation item is smaller than 1. The wireless communication system according to claim 5, wherein when the determination is made, the packet including the normal data is transmitted at the second transmission power in the second frequency band.   The second radio apparatus further performs a third process of obtaining an extrapolated value by extrapolating the Kmax evaluation items, and when it is determined that the extrapolated value is smaller than 1, The wireless communication system according to claim 5, wherein a packet including the normal data is transmitted with the second transmission power in two frequency bands.   The second radio apparatus multiplies the target signal-to-noise interference ratio by the interference power, and multiplies the operation result by a predetermined constant greater than 0 and less than 0.5. In the power range obtained by the above, the first processing is executed while changing the first transmission power to m (m is 2 or more) first transmission powers, and the m first transmission powers are obtained. The second processing is performed on m, m groups each including Kmax interference power are acquired, and the third processing is performed on the m groups to perform m out of An extrapolated value is estimated, and an extrapolated maximum value extrapolated when the transmission power obtained by multiplying the target signal-to-noise interference ratio by the interference power is used, and the extrapolated maximum value is When it is determined that the frequency is less than 1, the second frequency Transmitting a packet including the normal data in the second transmission power in a band, the wireless communication system of claim 7.

Images