JP2010178225A - Radio system, transmitter, transmitting electric power decision method, and program - Google Patents

Abstract

A frequency band is shared by limiting interference to other wireless systems sharing the frequency.
Communication quality acquisition means for estimating or acquiring communication quality values of transmitters and receivers constituting another radio system sharing frequency, and output of the communication quality acquisition means, to a radio system sharing frequency Based on the communication quality value, means for calculating and processing the allowable interference power to be allowed to the receiver of the other wireless system, and determining the maximum transmission power for the receiver of the other wireless system based on the calculated allowable interference power Means for processing.
[Selection] Figure 3

Description

  The present invention relates to a technique in which a plurality of wireless systems perform communication by sharing a frequency, and more particularly, to a technique for determining power transmitted from a transmitter of the wireless system.

  A wireless communication system (hereinafter referred to as “frequency sharing method”) that uses the same frequency band as a wireless system having priority to use a frequency band (hereinafter referred to as “primary system”). , Described as secondary system).

  Such frequency sharing methods include, for example, using a cognitive radio system as a secondary system, frequency sharing between a macro cell base station and a femto cell base station, frequency sharing between a macro cell base station and a relay station, and other meshes. It is used in the form of frequency sharing between network type communication nodes.

  When the secondary system and the primary system share the frequency band, it is necessary to protect the communication quality of the primary system having the priority of using the frequency band. For this reason, the secondary system is required to communicate while suppressing interference with the primary system.

  Non-patent documents 1 and 2 can be cited as techniques for avoiding interference with the primary system, for example.

Non-Patent Document 1 describes a frequency sharing method using a priority communication system (primary system) and a non-priority communication system (secondary system). In addition, a method is described in which a transmission power control function (TPC: Transmission Power Control) is provided in a non-priority communication system, and the transmission power control function is controlled by a frequency sharing management server.
In the frequency sharing method described in Non-Patent Document 1, the base station (transmitter) of the non-prioritized communication system registers the use frequency and the geographical position in the frequency sharing management server, and the receiver of the prioritized communication system also uses the frequency. The installation position, operation status, frequency band to be used, allowable interference level (allowable interference level), etc. are registered in the shared management server. Thereafter, in the frequency sharing management server, by calculating the maximum power value (maximum transmission power) that can be transmitted from the non-priority communication system base station based on information such as the registered allowable interference level, and notifying the base station, A method that enables transmission power control based on the maximum transmission power in the base station has been proposed. In addition, an equation for calculating the allowable interference level from the thermal noise power density, the noise figure, and the margin is described.

  The secondary system described in Non-Patent Document 2 prepares a server in which information such as the installation position, transmission power, and service area of the transmission station of the primary system (TV broadcast system) is registered. Further, the secondary transmitter acquires its own position information with GPS or the like. The secondary system controls the maximum transmission power at the transmitter of the secondary system and determines the transmission power so that a minimum Desired to Undesired signal Ratio (DUR) can be secured at the end of the TV broadcast service area. Note that DUR is also referred to as Signal to Interference Ratio (SIR).

Hiromasa Fujii Hitoshi Yoshino Capacity analysis of frequency sharing method with transmission power control in multi-cell environment SR2008-54 David Gurney, Greg Buchwald, Larry Ecklund, Steve Kuffner, and Joho Grosspietsch “Geo-location Database Techniques for Incumbent Protection in the TV White Space”, DySPAN 2008.

  However, the technique described in Non-Patent Document 1 has a problem that the received power of the primary signal cannot be considered because the allowable interference level is calculated from the thermal noise power density, the noise figure, and the margin. When the received power varies depending on the position of the primary receiver, the primary receiver having the originally high SNR is compared with the primary receiver having the originally low Signal to Noise power Ratio (SNR) (or Signal to Interference and Noise Ratio (SINR)). There is a possibility that the interference of the same power is allowed, which may cause deterioration in communication quality.

  Unlike the non-patent document 1, the technique described in the non-patent document 2 determines the maximum transmission power in the secondary system so as to guarantee the minimum SIR or SINR in the primary receiver. The minimum quality can be guaranteed for the receiver, and the influence of the start of secondary communication can be suppressed.

  However, depending on the size of the SNR to be guaranteed, there may be a case where a large amount of interference is allowed for a primary receiver having an originally high SNR. At this time, the throughput in the primary receiver having a high SNR may be greatly degraded.

  That is, in the techniques described in Non-Patent Document 1 and Non-Patent Document 2, only the communication of either the primary receiver having a low SNR or the receiver having a high SNR can be protected.

  The present invention solves the above-described problems, and a radio system and a transmission power determination method that adaptively control allowable interference power and maximum transmission power for another radio system receiver according to the original communication quality in the other radio system. The purpose is to provide.

  The wireless system of the present invention is based on the communication quality acquisition means for estimating or acquiring the communication quality value of the transmitter and the receiver constituting the other wireless system, and the communication quality value output from the communication quality acquisition means, And a means for calculating an allowable interference power allowed by the receiver and a means for determining a maximum transmission power for the receiver based on the calculated allowable interference power.

  The method for determining transmission power of a wireless system according to the present invention estimates or acquires the communication quality of a transmitter and a receiver constituting another wireless system, and automatically determines the transmission quality based on the estimated or acquired communication quality. The interference power given from the transmitter of the wireless system is determined, based on the communication quality value output from the communication quality acquisition means, the interference power allowed to the receiver is calculated, and based on the determined interference power Determining the maximum transmission power of the transmitter of the own radio system relative to the receiver of the other radio system.

  ADVANTAGE OF THE INVENTION According to this invention, the radio | wireless system and transmission power determination method which adaptively control the allowable interference power and the maximum transmission power with respect to another radio system receiver according to the original communication quality in another radio system can be provided.

It is explanatory drawing which shows roughly the two radio | wireless systems which share the frequency of this invention. It is a functional block diagram which shows a part of secondary transmitter relevant to the power control which concerns on this invention. It is a flowchart which shows the transmission process performed when the secondary system which concerns on this invention starts communication. It is explanatory drawing which illustrates the table information in which the communication quality and the retention rate of the interference were described. It is explanatory drawing which shows the simulation result which compared 1st Embodiment and the technique described in the nonpatent literature 2. FIG. It is explanatory drawing which illustrates the extended MCS set which employ | adopts an adaptive modulation system. It is explanatory drawing which shows the transmission rate which changes for every extended MCS set.

  Hereinafter, the present invention will be described in detail with reference to a plurality of embodiments. Note that details that are not related to the present invention are omitted or simplified for the sake of clarity.

First, a first embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG.
FIG. 1 is an explanatory diagram schematically showing two radio systems sharing the frequency of the present invention. FIG. 1 shows a primary system 10 having a priority to use a frequency band and a secondary system 20 that improves frequency utilization efficiency by sharing and using the same frequency band. In addition, a primary information registration server 30 capable of communicating with the primary system 10 and the secondary secondary system 20 is described.

  The primary system 10 includes a primary transmitter 11 and a primary receiver 12, and is a communication or broadcast radio system. The primary system 10 collects data (primary information) in order to acquire or estimate the communication quality between the primary system transceivers in the secondary system 20 and registers it in the primary information registration server 30.

  The secondary system 20 is a wireless communication system including a secondary transmitter 21 and a secondary receiver 22. Before the secondary system 20 sends out radio waves that cause interference to the primary system 10, the interference caused by the radio transmission of the secondary transmitter 21 is based on the communication quality value between the primary transmitter 11 and the predetermined primary receiver 12. A maximum transmission power control unit 200 that determines the maximum transmission power to be transmitted from the secondary transmitter 21 so as to be equal to or less than the interference power that can be permitted by the primary receiver 12 (allowable interference power). The secondary transmitter 200 performs transmission power control within a range not exceeding the maximum transmission power determined by the maximum transmission power control unit 200, and transmits to the secondary receiver 22 sharing the frequency band used by the primary system 10. A transmission power control unit 210 that determines power to be transmitted.

  The primary information registration server 30 provides the secondary system 20 with data (primary information) collected by the primary system 10 for estimating communication quality or communication quality between primary system transceivers. The secondary system 20 can estimate or acquire the communication quality value between the primary transmitter 11 and the predetermined primary receiver 12 based on the primary information acquired via the primary information registration server 30 and data stored in advance.

FIG. 2 is a functional block diagram showing a part of a secondary transmitter related to power control according to the present invention.
The maximum transmission power control unit 200 includes a primary system communication quality acquisition unit 201, a primary system allowable interference power calculation unit 202, and a maximum transmission power calculation unit 203.

  The primary system communication quality acquisition unit 201 estimates or acquires a communication quality value from the primary transmitter 11 to the primary receiver 12.

  The primary system allowable interference power calculation unit 202 is an allowable interference power value that is an allowable interference value even if given to a predetermined primary receiver based on a communication quality value output as a value of the predetermined primary receiver. Is calculated.

  The maximum transmission power calculation unit 203 determines a maximum transmission power value for radio wave transmission that causes interference with the primary receiver 12 based on the allowable interference power value.

  Further, the secondary transmitter 21 determines the transmission power for the secondary receiver 22 with the maximum transmission power determined by the maximum transmission power control unit 200 as a maximum value, sends the transmission power result to the amplifier, and transmits the radio wave. . In the transmission power control, the transmission power of the secondary transmitter 21 is determined based on the radio propagation environment between the secondary transmitter 21 and the secondary receiver 22. For example, the secondary transmitter 21 first transmits a radio wave with a predetermined transmission power smaller than the maximum transmission power, and the secondary receiver that receives the radio wave notifies the secondary transmitter 21 of the reception power, and the secondary transmitter 21 is notified. Based on the received power, it is possible to use control such as increasing or decreasing the transmission power as necessary within the range of the maximum transmission power or less.

Next, the communication start operation in the secondary system 20 will be described.
FIG. 3 is a flowchart showing a transmission process performed when the secondary system 20 starts communication.

The secondary system 20 acquires the communication quality in the predetermined primary receiver 12 from the primary information (step S101).
The secondary system 20 determines the allowable interference power of interference given to the primary receiver 12 according to the acquired communication quality (step S102).
The secondary system 20 considers the distance attenuation due to radio wave propagation between the secondary transmitter 21 and the primary receiver 12 and the attenuation due to shadowing and fading so that the interference to the primary receiver 12 is less than the allowable interference power. The maximum transmission power at the secondary transmitter 21 is determined (step S103).

The secondary system 20 performs transmission power control within a range not exceeding the maximum transmission power and transmits radio waves (step S104).
The secondary system 20 performs communication while sharing the frequency band used by the primary system 10 while repeating the processing from step S101 to step S104 every predetermined time or every predetermined timing.

  Here, the processing operation of each unit will be described in detail with the “throughput” between the primary system transceivers as the communication quality at the primary receiver.

[Estimation of primary communication quality]
The primary system communication quality acquisition unit 201 acquires, from the primary information registration server 30, position information of the primary transmitter 11, transmission power information of the primary transmitter 11, and position information of a predetermined primary receiver 12 as primary information. The primary system communication quality acquisition unit 201 calculates the distance between the primary transceivers based on the acquired location information of the primary transmitter 11 and the location information of the primary receiver 12.

  The primary system communication quality acquisition unit 201 considers distance attenuation, shadowing, attenuation due to fading, antenna gain of the primary transceiver, and the like based on the distance between the primary transceivers and the transmission power information. An estimated value of the received power of the primary signal at is calculated.

  The primary system communication quality acquisition unit 201 calculates an estimated SINR using the calculated estimated value of the received power of the primary signal, the expected interference power at the primary receiver, other noise power, and the like, and predetermined based on the SINR Throughput in the primary receiver 12 is calculated.

[Estimation of another primary communication quality]
The primary information registration server 30 registers the communication quality information (throughput) of the predetermined primary receiver 12 from the primary system 10, and the primary system communication quality acquisition unit 201 receives the communication quality information ( Throughput). Further, the primary system communication quality acquisition unit 201 acquires position information of the primary transmitter 11, transmission power information of the primary transmitter 11, and position information of a predetermined primary receiver 12 as primary information.

  Further, the primary information registration server 30 registers the primary received power, SINR, and the like with the predetermined primary receiver 12 from the primary system 10, and the primary system communication quality acquisition unit 201 acquires the information as the primary information, and the throughput is increased. You may calculate by calculating.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 stores table information (FIG. 4) that stores the allowable interference power associated with the wireless standard of the primary system, the current throughput of the primary receiver 12, and the retention ratio indicating the throughput retention ratio. Hold). Here, the retention rate α (0 <α <1) means that when the primary receiver 12 receives interference due to the secondary signal of the secondary system 20, compared with the original throughput of the primary receiver 12, after interference reception. It is a value that represents the percentage of throughput that can be retained.

  The primary system allowable interference power calculation unit 202 uses the table information to determine the allowable interference power for a predetermined primary receiver from the estimated or acquired information, such as the wireless standard, and the retention rate α.

  In this embodiment, the primary receiver is protected by using the same value of retention ratio α as the entire primary system, but the method of using retention ratio α is not limited to this. For example, when multiple primary systems exist in the same frequency band, a wireless system that requires high stability such as public relations sets a high retention rate, and a normal service has a retention rate lower than that of the wireless system. For example, different retention rates may be used for each primary system.

[Determine secondary maximum transmission power]
Based on the determined allowable interference power, the maximum transmission power calculation unit 203 determines the amount of radio wave attenuation (distance attenuation, shadowing, fading) between the secondary transmitter 21 and the primary receiver 12, the transmission antenna gain of the secondary transmitter 21, The maximum transmission power value transmitted from the secondary transmitter 21 for the primary receiver 12 is determined in consideration of the reception antenna gain of the primary receiver 12 and the like.

[Determining the maximum transmit power of another secondary]
The maximum transmission power calculation unit 203 transmits radio waves from the transmitter with power equal to or less than the maximum transmission power determined as described above, and sets the interference power of the secondary signal received as interference by the primary receiver 12 as a primary information registration server. 30, the amount of radio wave attenuation (distance attenuation, shadowing, fading) between the secondary transmitter 21 and the primary receiver 12 from the acquired interference power, the transmission antenna gain of the secondary transmitter 21, the reception of the primary receiver 12. It is also possible to obtain the influence of the antenna gain and redetermine the maximum transmission power value of the secondary transmitter 21.

  As described above, according to the present embodiment, radio capable of adaptively controlling the allowable interference power of the primary system and the maximum transmission power of the secondary system according to the original communication quality (throughput) in the primary system. A communication system can be provided.

  That is, both the low-quality primary receiver and the high-quality primary receiver can be protected from secondary interference, and communication using a common frequency can be performed.

  This is because in a primary system in which a low-quality receiver and a high-quality receiver are mixed, a high-quality receiver can tolerate more interference than a poor-quality receiver, so the communication quality is good. Allocating a lot of allowable interference power to receivers and allocating a small allowable interference power to receivers with poor communication quality, limiting the interference of the secondary system for any receiver Frequency sharing can be realized.

  That is, the ratio between the throughput after radio wave transmission and the throughput before deterioration is maintained at the retention rate α. Therefore, interference with a low-quality primary receiver can be made very small. On the other hand, the interference with the high-quality primary receiver is relatively large, but since the amount of degradation is determined from the retention rate, the performance is not significantly reduced.

  In the above description, a single primary receiver is described. However, a plurality of primary receivers may be used. In this case, the primary transmitter 21 may calculate the maximum transmission power value for each primary receiver and determine the transmission power from the minimum value of the maximum transmission power value.

  As an example, the frequency sharing method according to the present embodiment and the technique disclosed in Non-Patent Document 2 were compared and verified by computer simulation (see FIG. 5). However, in this simulation, a comparison is made with a channel capacity that has a positive correlation with the throughput, instead of the throughput of the primary system.

  The horizontal axis of FIG. 5 represents the distance [m] between the cell center (transmitter position: antenna installation position) of the primary system and the primary receiver. The vertical axis represents the channel capacity [bps / Hz] at the primary receiver located on the line connecting the cell center and the secondary transmitter in logarithmic notation. In FIG. 5, the frequency sharing method according to the present embodiment is expressed as “constant retention”, and the method of Non-Patent Document 2 is expressed as “SIR constant”. In addition, for comparison, the channel capacity at the primary receiver before the secondary system starts communication is described as “no secondary interference”.

  Further, in this computer simulation, it is assumed that the primary system is a downlink of a wireless communication system in which an isolated circular cell having a radius of 1400 m is used as a service area and one primary receiver exists in the cell. The secondary system has a secondary transmitter at a point 500 m away from the cell edge of the primary system and communicates with a secondary receiver 50 m away. The radio propagation path between the primary system transceiver and the secondary system transceiver only considers distance attenuation.

  In the frequency sharing method according to the present embodiment, the allowable interference power is determined by setting the retention rate of the channel capacity of the primary system to 0.9. The secondary transmitter is assumed to communicate using the maximum transmission power obtained from the allowable interference power. In the technique of Non-Patent Document 2, not only the primary receiver at the cell end of the primary system but also the SIR of the primary receiver in the cell is secured. In addition, in order to compare fairly the frequency sharing method method of this Embodiment and the technique of patent document 2, the average value of the secondary channel capacity obtained using each method is equalized.

  As can be seen from FIG. 5, in the frequency sharing according to the present embodiment, the communication path is based on the retention rate α without greatly degrading the communication path capacity of the primary system as compared with the case where there is no interference from the secondary system. It can be seen that the capacity can be maintained. On the other hand, in the technique of Patent Document 2, in order to obtain the same channel capacity of the secondary system as in the present embodiment, the channel capacity of the primary receiver having a high SNR existing in the cell center of the primary system is greatly deteriorated. Yes. From this, it can be seen that the primary receiver near the center of the cell can be protected by using the frequency sharing method of the present embodiment.

  Next, as the second embodiment, “SNR (or Signal to Interference Ratio (SIR) or SINR is acceptable)” at the primary receiver is used as communication quality at the primary receiver, and the processing operation of each part is detailed. Explained. Note that the description of the same configuration and operation as in the first embodiment is omitted for the sake of brevity.

[Estimation of primary communication quality]
For the primary communication quality, the primary system communication quality acquisition unit 201 estimates the received power of the primary signal from the distance of the primary transceiver 12 and the primary transmission power, and calculates the SNR (or SIR or SINR).

  When the primary system registers SNR, SIR, SINR, etc. in the primary information registration server 30, the primary system communication quality acquisition unit 201 receives the location information, primary received power, SNR, SIR from the primary information registration server 30. , SINR, etc. are acquired.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 prepares a table of allowable interference power according to the primary SNR or the like to be estimated or acquired, and determines the allowable interference power.

[Determine secondary maximum transmission power]
The maximum transmission power calculation unit 203 determines the maximum transmission power value based on the determined allowable interference power, the distance between the secondary transmitter 21 and the primary receiver 12, and the like. Alternatively, the maximum transmission power calculation unit 203 may acquire the interference power at the primary receiver 12 via a server and correct the maximum transmission power value.

  As described above, in the maximum transmission power control unit 200, the secondary system 20 determines the allowable interference power for the primary receiver according to the original SNR in the primary receiver, and determines the maximum transmission power output from the secondary transmitter. Then, the transmission power control unit 210 performs transmission power control within a range not exceeding the maximum transmission power based on the determined allowable interference power value, and shares the frequency band used by the primary system 10 with the secondary receiver. 22 to communicate.

  The secondary system 20 can determine the maximum transmission power transmitted from the secondary transmitter 21 by acquiring or estimating the SNR, SIR, and SINR at the primary receiver by performing the operation process as described above.

  Next, as a third embodiment, the processing operation of each unit will be described in detail with the “extended Modulation and Coding Scheme (MCS) set” of the primary receiver as the communication quality at the primary receiver. Note that the description of the same configuration and operation as in the first embodiment is omitted for the sake of brevity.

  In a primary system that adopts an adaptive modulation scheme, a combination of a modulation scheme, a coding rate, and the number of Multi Input Multi Output (MIMO) streams (hereinafter referred to as an extended MCS set) based on, for example, a table as shown in FIG. ). The transmission rate of communication at such a primary receiver changes stepwise according to the extended MCS set (see FIG. 7).

[Estimation of primary communication quality]
The primary system allowable interference power calculation unit 202 uses, as primary information, an extended MCS set (a combination of a modulation scheme, a coding rate, and the number of MIMO streams) used by a predetermined primary receiver together with position information, primary transmission power, and the like as primary information. Obtained from the information registration server 30.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 prepares a table of allowable interference power according to the acquired primary extended MCS set, and determines the allowable interference power. In addition, since the combination of the extended MCS set is determined discontinuously according to the allowable interference power, a table in consideration thereof is held (see FIG. 6).

  The primary system allowable interference power calculation unit 202 determines the allowable interference power so as to remain in the same extended MCS set used by the primary receiver by estimating or acquiring the SINR of the current primary receiver. . Also, if the allowable interference power amount cannot be secured if the same extended MCS set is kept, the allowable interference is set so that the transmission rate is shifted to the extended MCS set with n levels (n is a positive integer) and stays at that level. Determine the power.

[Determine secondary maximum transmission power]
The maximum transmission power calculation unit 203 determines the maximum transmission power value based on the determined allowable interference power, the distance between the secondary transmitter 21 and the primary receiver 12, and the like. Alternatively, the maximum transmission power calculation unit 203 acquires the interference power or the like at the primary receiver 12 via the server, and determines the maximum transmission power value.

  As described above, in the maximum transmission power control unit 200, the secondary system 20 determines the allowable interference power for the primary receiver according to the original extended MCS set in the primary receiver, and the maximum transmission output from the secondary transmitter 21. After determining the power, the transmission power control unit 210 performs transmission power control in a range not exceeding the maximum transmission power based on the determined allowable interference power value, and shares the frequency band used by the primary system to the secondary Communicate with the receiver 22.

  The secondary system 20 obtains the current extended MCS set at the primary receiver by performing the operation process as described above, and the secondary transmitter 21 can protect the transmission rate of the primary transmitter based on the extended MCS set. The maximum transmission power to be transmitted can be determined.

  In the present embodiment, the extended MCS set (combination of modulation scheme, coding rate, and number of MIMO streams) is described, but each of modulation scheme, coding rate, number of MIMO streams, or any combination thereof. The form of using may be used.

  Next, as a fourth embodiment, the processing operation of each unit will be described in detail with the “bit (packet) error rate” of the primary receiver as the communication quality at the primary receiver. Note that the description of the same configuration and operation as in the first embodiment is omitted for the sake of brevity.

  When a wireless system that performs communication or broadcasting by adopting a packet communication method is used as a primary system, the bit error rate / packet error rate can be used as the communication quality at the primary receiver.

[Estimation of primary communication quality]
For the primary communication quality, the primary system communication quality acquisition unit 201 acquires, from the primary information registration server 30, the bit error rate / packet error rate used in a predetermined primary receiver together with position information, primary transmission power, etc. as primary information. To do.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 prepares a table of allowable interference power according to the acquired bit error rate / packet error rate of the primary system, and determines the allowable interference power.

[Determine secondary maximum transmission power]
The maximum transmission power calculation unit 203 determines the maximum transmission power value based on the determined allowable interference power, the distance between the secondary transmitter 21 and the primary receiver 12, and the like. Alternatively, the maximum transmission power calculation unit 203 acquires the interference power or the like at the primary receiver 12 via the server, and determines the maximum transmission power value.

  Thus, the secondary transmission system 20 determines the allowable interference power for the primary receiver in the maximum transmission power control unit 200 according to the original bit error rate / packet error rate in the primary receiver, and from the secondary transmitter 21. The maximum transmission power to be output is determined, and the transmission power control unit 210 performs transmission power control within a range not exceeding the maximum transmission power based on the determined allowable interference power value, and sets the frequency band used by the primary system. Share and communicate with the secondary receiver 22.

  The secondary system 20 can determine the maximum transmission power transmitted from the secondary transmitter 21 according to the bit error rate / packet error rate at the primary receiver by performing the operation process as described above.

  Next, as a fifth embodiment, the processing operation of each unit will be described in detail with “required quality of application” of the primary receiver as communication quality at the primary receiver. Note that the description of the same configuration and operation as in the first embodiment is omitted for the sake of brevity.

  When a wireless system that performs communication or multimedia broadcasting using the required quality (level) of the application is used as the primary system, the required quality of the application can be used as the communication quality at the primary receiver.

  The required quality of the application is a value indicating a delay amount or communication quality determined by the application or user used in the primary receiver and / or its higher-level information processing apparatus for each voice call, data communication, streaming, etc. It is.

[Estimation of primary communication quality]
The primary system communication quality acquisition unit 201 acquires the required quality of an application used in a predetermined primary receiver from the primary information registration server 30.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 determines the allowable interference power based on a table of allowable interference power corresponding to an application (for example, allowable interference power high: data communication, allowable interference power medium: streaming, allowable interference power low: voice call). The interference power is determined and processed.

[Determine secondary maximum transmission power]
The maximum transmission power calculation unit 203 determines the maximum transmission power value based on the determined allowable interference power, the distance between the secondary transmitter 21 and the primary receiver 12, and the like. Alternatively, the maximum transmission power calculation unit 203 acquires the interference power or the like at the primary receiver 12 via the server, and determines the maximum transmission power value.

  Thus, in the maximum transmission power control unit 200, the secondary system 20 determines the allowable interference power for the primary receiver according to the required quality of the original application in the primary receiver, and outputs the maximum output from the secondary transmitter 21. After determining the transmission power, the transmission power control unit 210 performs transmission power control in a range not exceeding the maximum transmission power based on the determined allowable interference power value, and shares the frequency band used by the primary system. Communication with the secondary receiver 22 is performed.

  The secondary system 20 can determine the maximum transmission power transmitted from the secondary transmitter 21 so as to adapt to the required quality of the application in the primary receiver by performing the operation process as described above.

  Next, as the sixth embodiment, the processing operation of each unit will be described in detail with the “movement speed” of the primary receiver as the communication quality at the primary receiver. For the sake of brevity, description of the same configuration and operation as in the first embodiment will be omitted.

  When a wireless system that can communicate while moving and a wireless system that can detect the moving speed with a higher-level information processing device connected to it is used as the primary system, use the moving speed as the communication quality of the primary receiver. Can do.

[Estimation of primary communication quality]
The primary system communication quality acquisition unit 201 acquires a moving speed of a predetermined primary receiver from the primary information registration server 30. Alternatively, the primary system communication quality acquisition unit 201 calculates an estimated value of the moving speed from the current position information and past position information of the primary receiver.

[Determination of primary allowable interference power]
The primary system allowable interference power calculation unit 202 is based on a table of interference power corresponding to the estimated or acquired movement speed (for example, 0 to 15 km / h, 15 km / h to 60 km / h, 60 km / h) of the primary system. Then, the allowable interference power is determined and processed. This is because the primary signal demodulation processing at the primary receiver becomes more difficult as the moving speed increases, so even if the received power of the primary signal is about the same, the reception quality differs depending on the moving speed. This is because the allowed interference differs depending on the reception quality corresponding to the.

[Determine secondary maximum transmission power]
The maximum transmission power calculation unit 203 determines the maximum transmission power value based on the determined allowable interference power, the distance between the secondary transmitter 21 and the primary receiver 12, and the like. Alternatively, the maximum transmission power calculation unit 203 acquires the interference power or the like at the primary receiver 12 via the server, and determines the maximum transmission power value.

  As described above, the maximum transmission power control unit 200 determines the allowable interference power for the primary receiver according to the original moving speed in the primary receiver, and the maximum transmission power output from the secondary transmitter 21 in the secondary transmission system 20. The transmission power control unit 210 performs transmission power control in a range not exceeding the maximum transmission power based on the determined allowable interference power value, and shares the frequency band used by the primary system for secondary reception. Communicate with the machine 22.

  The secondary system 20 can determine the maximum transmission power transmitted from the secondary transmitter 21 by acquiring or estimating the moving speed at the primary receiver by performing the operation process as described above.

  In the present embodiment, the “movement speed” of the primary receiver has been described as the communication quality at the primary receiver, but the movement speed may be further used for other purposes. For example, when acquiring communication quality information and the like of the primary receiver in step S101 in FIG. 3, the primary receiver of high speed movement has a short time cycle (acquisition timing) of acquiring communication quality and the like, and the primary receiver of low speed movement It is also possible to change the update frequency of the communication quality information according to the moving speed, such as extending the time cycle. Furthermore, when the distance between the secondary transmitter and the primary receiver and the distance between the primary transmitter and the primary receiver are obtained from the position information, a distance estimation with a margin is performed on the primary receiver moving at high speed, etc. The distance can be estimated according to the moving speed.

  As described above with reference to the plurality of embodiments, according to the present invention, the allowable interference power of the primary system and the maximum transmission power of the secondary system are adaptively controlled according to the original communication quality in the primary system. A wireless communication system can be provided.

  Further, according to the present invention, it is possible to provide a transmission power determination method in a wireless communication system that adaptively controls the allowable interference power of the primary system and the maximum transmission power of the secondary system according to the original communication quality in the primary system.

  In addition, a secondary system may have many primary systems with respect to the frequency band to be used, and the said system is suitable also for such a secondary system. That is, for each primary system, the secondary system can acquire communication quality information from each primary system, adaptively perform arithmetic processing for each acquired communication quality, and determine the maximum transmission power transmitted from the secondary system.

  This is not only for one primary system in which a low-quality receiver and a high-quality receiver are mixed, but also for two primary systems that employ different communication methods, for each acquired communication quality. This is because the maximum transmission power can be calculated and the maximum transmission power of the secondary system can be determined based on the smaller value to control the transmission power.

  Each unit of the secondary system may be realized using hardware or a combination of hardware and software. In a form in which hardware and software are combined, a program is developed in the RAM, and each unit is realized by operating hardware such as a control unit based on the program. The program may be recorded on a storage medium and distributed. The program recorded in the recording medium is read into a memory via a wired, wireless, or recording medium itself, and operates a control unit or the like.

  In addition, the maximum transmission power control unit provided in the secondary system may be provided in the transmitter, or may be provided in a server or the like different from the transmitter. In the case where it is provided separately from the transmitter, it can also be provided on a server shared with the primary information registration server. That is, the maximum transmission power control unit may be provided anywhere as long as it can communicate with the transmission power control unit provided in the transmitter in a wired or wireless manner.

  The operation process of the primary information registration server may be performed on the secondary system side or the primary system side. When the primary system registration process is performed on the primary system side, the primary system and the secondary system may be configured to communicate directly.

  The present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and operation of the present invention within the scope of the claims of the present invention.

  The present invention can be applied to a cognitive radio system. Further, the present invention can be applied to frequency sharing between the macro cell base station and the femto cell base station, frequency sharing between the macro cell base station and the relay station, and other wireless systems that share frequency between mesh network type communication nodes.

10 Primary system 11 Primary transmitter (Primary system transmitter)
12 Primary receiver (Primary system receiver)
20 Secondary system 21 Secondary transmitter (secondary system transmitter)
22 Secondary receiver (secondary system receiver)
30 Primary information registration server (primary information providing server)
200 Maximum Transmission Power Control Unit 201 Primary System Communication Quality Acquisition Unit (Communication Quality Acquisition Unit)
202 Primary system allowable interference power calculation unit (allowable interference power calculation means)
203 Maximum transmission power calculation unit (maximum transmission power calculation means)
210 Transmission power control unit

Claims (12)

Communication quality acquisition means for estimating or acquiring communication quality values of transmitters and receivers constituting another wireless system;
Based on the communication quality value output by the communication quality acquisition means, the allowable interference power calculation means for calculating the allowable interference power allowed to the receiver,
A wireless system comprising: a maximum transmission power calculation unit that determines a maximum transmission power for the receiver based on the calculated allowable interference power. The wireless system according to claim 1,
The wireless system uses any one or more of the communication quality such as throughput, SNR, SIR, SINR, bit error rate, packet error rate, application required quality, moving speed, modulation method, coding rate, and number of MIMO streams. The wireless system according to claim 1 or 2,
The transmission power of the transmitter of the own radio system is determined based on the radio propagation environment from the transmitter of the own radio system to the receiver of the own radio system, with the maximum transmission power for the receiver subjected to the determination process being a maximum value. A wireless system characterized by processing. Communication quality acquisition means for estimating or acquiring communication quality values of transmitters and receivers constituting another wireless system;
Based on the communication quality value output by the communication quality acquisition means, allowable interference power calculation means for calculating allowable interference power to be allowed to the receiver of the other wireless system;
A transmitter comprising: maximum transmission power calculation means for determining a maximum transmission power for a receiver of the other radio system based on the calculated allowable interference power. The transmitter according to claim 4, wherein
The transmitter using the communication quality using one or more of throughput, SNR, SIR, SINR, bit error rate, packet error rate, required quality of application, moving speed, modulation scheme, coding rate, number of MIMO streams. The transmitter according to claim 4 or 5, wherein
Determining the transmission power to be transmitted to the receiver of the own radio system based on the radio propagation environment up to the receiver of the own radio system, with the maximum transmission power to the receiver subjected to the decision process being a maximum value; Transmitter characterized by. Estimating or obtaining the communication quality of transmitters and receivers constituting other wireless systems,
Based on the estimated or acquired communication quality, the interference power given to the receiver from the transmitter of its own radio system is determined,
A radio system transmission power determination method, comprising: determining a maximum transmission power of a transmitter of the own radio system with respect to a receiver of the other radio system based on the determined interference power. The transmission power determination method according to claim 7,
Transmission power determination method using any one or more of throughput, SNR, SIR, SINR, bit error rate, packet error rate, application required quality, moving speed, modulation scheme, coding rate, number of MIMO streams as the communication quality . The transmission power determination method according to claim 7 or 8,
The transmission power of the transmitter of the own radio system is determined based on the radio propagation environment from the transmitter of the own radio system to the receiver of the own radio system, with the maximum transmission power for the receiver subjected to the determination process being a maximum value. A transmission power determination method comprising: processing. The control unit provided in the wireless system
Communication quality acquisition means for estimating or acquiring communication quality values of transmitters and receivers constituting another wireless system;
Based on the communication quality value output by the communication quality acquisition means, the allowable interference power determination means for calculating the allowable interference power allowed to the receiver,
A program that functions as a maximum transmission power calculation unit that determines a maximum transmission power for the receiver based on the calculated allowable interference power. A program according to claim 10, wherein
A program that operates using the communication quality using one or more of throughput, SNR, SIR, SINR, bit error rate, packet error rate, required quality of application, moving speed, modulation method, coding rate, number of MIMO streams . The program according to claim 10 or 11,
The transmission power of the transmitter of the own radio system is determined based on the radio propagation environment from the transmitter of the own radio system to the receiver of the own radio system, with the maximum transmission power for the receiver subjected to the determination process being a maximum value. A program characterized by processing.

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