JP6127746B2 - Frequency allocation apparatus, frequency allocation method, and program - Google Patents

Description

  The present invention relates to a frequency allocation device, a frequency allocation method, and a program, and more particularly to a frequency allocation technique in request assignment multiple access considering intermodulation.

  Today, demand-assigned multiple access (DAMA), which is a method of frequency division multiple access (FDMA), is adopted in satellite communication, for example. According to FDMA, a communication frequency band is divided into a plurality of frequency bands (lines) and assigned to each radio station. Also, according to DAMA, line assignment is performed when each radio station makes a request to the line control station.

  In FDMA, it is necessary to perform frequency allocation in consideration of the influence of intermodulation when allocating lines to radio stations. For example, Non-Patent Document 1 describes a method of arranging the maximum number of lines that can be allocated while suppressing the influence of intermodulation.

“Intermediation Interference-Minimum Frequency Assignment for Satellite SCPC Systems”, IEEE Transactions On Communications, April 1984, Vol. 32, no. 4, p. 462-468

  However, when DAMA connection is performed, frequency allocation is sequentially performed every time a channel allocation request is made by a wireless station, so the number of allocated channels is not always the maximum number of channels. Rather, in many cases, the number of lines is smaller than the maximum number of lines.

  For this reason, it is desirable to perform frequency allocation while suppressing the influence of intermodulation even when the number of lines is smaller than the maximum number of lines, but such a method has not yet been studied.

  The present invention has been made to solve such problems, and a frequency allocation apparatus and a frequency allocation method capable of frequency allocation while suppressing the influence of intermodulation in request allocation multiple access And to provide a program.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  A frequency allocation apparatus according to the present invention includes a maximum channel allocation unit that allocates a predetermined number of channels within a given communication frequency band to generate a channel set, and a channel allocation order that determines an allocation order of the channels to radio stations A determination unit and a line arrangement order storage unit for storing the allocation order, wherein the line arrangement order determination unit has a difference between a carrier power and a noise level caused by cross-correlation in the line set. A process of calculating the first worst interference value, which is the noise level of the smallest line, and carrier power and mutual power when all the lines included in the line set are temporarily deleted from the line set. A process of calculating a second worst interference value, which is the noise level of a line with the smallest difference between the noise level caused by the correlation, and the second worst interference value of the second worst interference value. Storing the line temporarily deleted when the second worst interference value having the largest difference from the worst interference value is calculated is stored in the line arrangement order storage unit as a line to be assigned in a late order; Is to execute.

  A frequency allocation method according to the present invention is a method for determining an allocation order of channels to a radio station, and includes a maximum channel allocation step for generating a channel set by allocating a predetermined number of channels within a given communication frequency band. Calculating a first worst interference value that is the noise level of a line having a smallest difference between carrier power and noise level caused by cross-correlation among the line set, and all included in the line set For each of the channels, the second worst interference value, which is the noise level of the channel where the difference between the carrier power and the noise level caused by cross-correlation is the smallest when the channel is temporarily deleted from the channel set, is calculated. And temporary deletion when the second worst interference value having the largest difference between the first worst interference value and the second worst interference value is calculated. The line which is intended to include the steps of storing in said circuit arrangement order storage unit as the line to be assigned at a later sequence, the.

  The program according to the present invention is a program for causing a computer to execute the above method.

  The frequency allocation system according to the present invention includes a frequency allocation apparatus, a DAMA access master apparatus, and a DAMA access slave apparatus, and the frequency allocation apparatus allocates a predetermined number of lines within a given communication frequency band. A maximum line arrangement unit that generates a line set, a line arrangement order determination unit that determines an assignment order of the lines to the DAMA access slave device, and a line arrangement order storage unit that stores the assignment order, The line arrangement order determination unit calculates a first worst interference value that is the noise level of a line having a smallest difference between carrier power and a noise level caused by cross-correlation in the line set; For all the lines included in the line set, when the line is temporarily deleted from the line set, the carrier power and the noise level generated by the cross-correlation. The difference between the second worst interference value that is the noise level of the line with the smallest difference between the first worst interference value and the second worst interference value is the largest. The DAMA access master device performs the processing of storing the channel temporarily deleted when the large second worst interference value is calculated in the channel arrangement order storage unit. In response to the request, the lines stored in the line arrangement order storage unit are allocated to the DAMA access slave apparatus in the slowest order.

  According to the present invention, it is possible to provide a frequency allocation device, a frequency allocation method, and a program that can perform frequency allocation while suppressing the influence of intermodulation in request allocation multiple access.

It is a figure which shows the structure of the frequency allocation apparatus 100 of Embodiment 1 of this invention. It is a figure which shows the structure of the frequency allocation system 1000 of Embodiment 1 of this invention. It is a figure which shows the process of the frequency arrangement | positioning apparatus 100 of Embodiment 1 of this invention. It is a figure which shows the process of the frequency arrangement | positioning apparatus 100 of Embodiment 1 of this invention.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.
<Embodiment 1>
First, the configuration of the frequency allocation device 100 according to the first exemplary embodiment will be described with reference to FIG.

  The frequency allocation apparatus 100 includes a maximum line allocation unit 101, a line allocation order determination unit 102, and a line allocation order storage unit 103. The frequency allocation device 100 is realized by hardware such as a central processing unit (CPU), a volatile or nonvolatile storage device, and an input / output device. The maximum line arrangement unit 101 and the line arrangement order determination unit 102 are logical information processing means realized by the CPU executing various controls based on a control program stored in the storage device. The line arrangement order storage unit 103 is a logical storage unit that is realized using the storage device.

  The frequency allocation device 100 is a device that determines the most desirable frequency allocation order when performing line allocation by request allocation multiple access in a given communication frequency band.

  The maximum line arrangement unit 101 performs a process of determining a frequency arrangement when arranging the maximum line in a given communication frequency band.

  The channel allocation order determining unit 102 performs processing for determining in what order these frequencies should be allocated to the radio stations on the assumption of the frequency allocation determined by the maximum channel allocation unit 101.

  Next, an example of the frequency allocation system 1000 including the frequency allocation device 100 will be described with reference to FIG.

  The frequency allocation system 1000 includes a frequency allocation device 100, a DAMA access master device 200, and one or more DAMA access slave devices 300.

  The frequency allocation device 100 and the DAMA access master device 200 are channel control stations that perform channel allocation in response to a request from the DAMA access slave device 300. The DAMA access slave device 300 is a radio station that makes a line assignment request to the line control station.

  The frequency allocation apparatus 100 first inputs the maximum number of lines in the communication frequency band. Based on the maximum number of lines, the frequency allocation apparatus 100 determines in advance an optimal frequency allocation and an optimal frequency allocation order at the maximum number of lines by a method described later. The frequency allocation apparatus 100 notifies the DAMA access main apparatus 200 of the determined frequency and its allocation order.

  The DAMA access slave device 300 makes a line allocation request to the DAMA access master device 200 via a modem. In response to this, the DAMA access master apparatus 200 determines the frequency to be allocated based on the allocation order determined by the frequency allocation apparatus 100 and notifies the DAMA access slave apparatus 300 via the modem. The DAMA access slave device 300 performs wireless communication using the notified frequency.

  Next, processing of the frequency allocation device 100 will be described using the flowchart of FIG. 3 and FIG.

S101: Determination of Frequency Arrangement at Maximum Line First, the maximum line arrangement unit 101 accepts input of a communication frequency band and the maximum number of lines available in that frequency band. For example, in satellite communication, the maximum number of lines is determined based on constraints such as the power capacity of the repeater. The maximum line arrangement unit 101 may accept the already determined maximum number of lines via the input unit, or may calculate the maximum number of lines using a known method based on the above-described constraint conditions.

  Next, the maximum line arrangement unit 101 arranges the maximum number of lines within a given communication frequency band. At this time, the maximum line arrangement unit 101 uses, for example, a technique described in Non-Patent Document 1 to perform frequency arrangement that can suppress the influence of intermodulation. The set of lines arranged here is hereinafter referred to as a line set for convenience.

  FIG. 4A shows the concept of the frequency allocation result in S101. In FIG. 4A, the horizontal axis indicates the communication frequency band, and the arrow located on the axis indicates the frequency at which the line arrangement is performed. The length of the arrow indicates the power of the carrier (carrier wave).

S102: Confirmation of Position and Value of Worst Interference Value The line arrangement order determination unit 102 calculates an interference value at each frequency of the lines included in the line set. Here, the interference value refers to a noise level that appears at the frequency of each line due to the influence of intermodulation between the lines. Any known method may be used to calculate the interference value.

  Subsequently, the line arrangement order determination unit 102 determines the worst (worst interference value) among these interference values. Here, the worst interference value refers to the interference value having the smallest difference between the carrier power and the noise level.

  In FIG. 4A, the size of the noise level is indicated by the height of a white rectangle. In the example of FIG. 4, the smallest difference between the carrier power (the length of the arrow) and the noise level is the frequency arranged on the leftmost side. Therefore, the frequency is the position of the worst interference value.

  The line arrangement order determining unit 102 holds the calculated position and value of the worst interference value.

S103: Confirm the position and value of the worst interference value when an arbitrary one line is temporarily deleted. The line arrangement order determination unit 102 determines the worst interference when a certain line is temporarily deleted from the lines included in the line set. The position of the value and its value are determined and held using the same method as in S102.

  The line arrangement order determining unit 102 sequentially performs this process for all lines included in the line set. That is, if the line set includes n lines f1, f2,... Fn, the line arrangement order determination unit 102 temporarily deletes f1, f2,. The position and value of the worst interference value that appears are determined and held.

  FIG. 4B shows an example of the worst interference value when one arbitrary line is temporarily deleted from the line arrangement shown in FIG. In the left figure, a hatched rectangle indicates an interference value when the frequency f1 is temporarily deleted, and a white rectangle indicates an interference value before the f1 temporary deletion. In this case, the worst interference value after f1 temporary deletion occurs in the third line from the left.

  On the other hand, in the right figure, a hatched rectangle indicates an interference value when the frequency f2 is temporarily deleted, and a white rectangle indicates an interference value before the f2 temporary deletion. In this case, the worst interference value after f2 temporary deletion occurs in the third line from the left.

  As described above, if any one line is temporarily deleted from the line set, the interference value in each line remaining in the line set changes, and the worst interference value may also change. The line arrangement order determination unit 102 performs such a trial for all the lines in the line set, and temporarily stores the worst interference values in all the trials.

S104: Confirm one line with the largest difference between the worst interference value in S102 and the worst interference value in S103. The line arrangement order determination unit 102 calculates the worst interference value calculated in S103, that is, f1, f2,. Difference between the worst interference value when one arbitrary line is temporarily deleted and the worst interference value calculated in S102, that is, the worst interference value when all the lines included in the line set are arranged (worst interference value difference) ) Respectively. Then, when the line is temporarily deleted from the line set, one line having the largest worst interference value difference is determined.

  FIG. 4B shows an example of the worst interference value difference when one arbitrary line is temporarily deleted from the line arrangement shown in FIG. In the left figure, the worst interference value of f1 (white rectangle) that is the worst interference value before f1 temporary deletion and the worst interference value (hatched in the third line from the left) that is the worst interference value after f1 temporary deletion. The difference from the (rectangle) is the worst interference value difference.

  On the other hand, in the right figure, the worst interference value before f2 temporary deletion occurs in the leftmost line (white rectangle), and the worst interference value after f2 temporary deletion occurs in the third line from the left ( Hatched rectangle). The worst interference value difference is the difference between the height of the white rectangle of the leftmost line and the height of the hatched rectangle of the third line from the left.

  The line arrangement order determination unit 102 tries to calculate the worst interference value difference in the case where all the lines included in the line set are temporarily deleted. Then, the worst interference value differences are compared with each other, the largest worst interference value difference in the trial is specified, and the line temporarily deleted when the worst interference value difference occurs is specified. It can be said that the line specified here is a frequency at which the influence of cross-correlation appears most greatly by the line assignment by DAMA.

S105: Delete one line specified in S104 The line arrangement order determination unit 102 deletes the line specified when the worst interference value difference becomes the largest in S104 from the line set, and sets it as a new line set. Here, the line arrangement order determination unit 102 stores the deleted lines in the line arrangement order storage unit 103 in a form in which the storage order can be identified. Typically, the line arrangement order storage unit 103 may be a stack type storage area. Alternatively, the table may be a table that can be stored with an index added to the line.

S106: Repeat S102 to S105 The line arrangement order determination unit 102 calculates the worst interference value for a new line set (using the same method as in S102). Further, the line arrangement order determining unit 102 calculates the worst interference value when a certain line is temporarily deleted from the new line set for all the lines included in the new line set (using the same method as in S103). Then, when the line is temporarily deleted, one line having the largest worst interference value difference is determined (using the same method as in S104). Then, the line arrangement order determining unit 102 deletes the determined one line from the line set to make a new line set. The line arrangement order determination unit 102 stores the lines deleted from the line set in the line arrangement order storage unit 103.

  The line arrangement order determining unit 102 sequentially repeats these procedures until the number of lines included in the line set becomes 2 or less. When the number of lines included in the line set is 2, the line arrangement order determination unit 102 stores the two lines included in the line set in the line arrangement order storage unit 103 in an arbitrary order.

S107: The reverse order of deletion is set as the line arrangement order. The line arrangement order determination unit 102 sets the reverse order of the order in which the lines are stored in the line arrangement order storage unit 103 as the arrangement order of these lines. That is, the last line stored in the line arrangement order storage unit 103 is a line that is first assigned to a radio station, and the first stored line is a last line that is assigned.

  The reason for this is that, as described above, it can be said that a line that is deleted from the line set at an earlier stage is a frequency at which the influence of cross-correlation appears greatly by being assigned in the DAMA line assignment. On the other hand, a line deleted from the line set at a later stage can be said to have a frequency that is relatively less affected by cross-correlation.

  Therefore, if line allocation is performed for radio stations in order from a frequency where the influence of cross-correlation is relatively small, the influence of cross-correlation can be suppressed as much as possible regardless of the number of allocated lines. It is. By suppressing the influence of cross-correlation, C / N (Carrier to Noise Ratio) can be improved.

  According to the present embodiment, the line arrangement order determining unit 102 arranges the lines included in the line set in the order of small influence of the cross-correlation and sets the line allocation order for the radio stations. Thereby, the influence of cross-correlation can be suppressed as much as possible regardless of the number of allocated lines.

  Further, according to the present embodiment, the frequency allocation apparatus 100 determines the line allocation order in advance and notifies the DAMA access main apparatus 200. As a result, the frequency allocation system 1000 can quickly perform line allocation in response to an allocation request from the DAMA access slave device 300.

<Embodiment 2>
The frequency allocation apparatus 100 according to the second embodiment is characterized in that the calculation amount can be reduced as compared with the first embodiment. Since the configuration of frequency allocation apparatus 100 in the second embodiment is the same as that in the first embodiment, description thereof is omitted.

  Processing of the frequency allocation device 100 according to the second exemplary embodiment will be described. Note that the description of the same processes as those in Embodiment 1 is omitted.

  S101 to S105: The same as in the first embodiment. That is, the maximum line arrangement unit 101 or the line arrangement order determination unit 102 determines the frequency arrangement at the time of the maximum line to form a line set, and confirms the position and value of the worst interference value. Further, the position of the worst interference value and the value when the arbitrary one line is temporarily deleted are confirmed, and the one line having the largest difference in the worst interference value is deleted from the line set. Further, the deleted line is stored in the line arrangement order storage unit 103.

S206: Repeat S102 to S105 The line arrangement order determination unit 102 repeats the processes of S102 to S105 until the number of lines in the line set is equal to or less than a predetermined threshold. That is, among the lines included in the line set, one line having the largest worst interference value difference is deleted, and the deleted line is stored in the line arrangement order storage unit 103.

  If the number of lines in the line set becomes equal to or less than the predetermined threshold value, the line arrangement order determination unit 102 does not repeat the processes of S102 to S105 thereafter, They are stored in the line arrangement order storage unit 103 in order.

  Here, the predetermined threshold is an arbitrary integer exceeding 2. The larger the predetermined threshold value, the more the calculation amount in the line arrangement order determining unit 102 can be reduced.

  For example, if the maximum number of lines is sufficiently large and the number of lines in the line set decreases compared to the maximum number of lines, it may be less meaningful to rank the remaining lines. . That is, in a scene where the number of lines arranged with respect to the width of the communication frequency band is small, the interference value may be small enough to be ignored. In such a case, the number of arranged lines that are considered to be within an allowable range of the interference value can be adopted as the threshold value.

  According to the present embodiment, the line arrangement order determination unit 102 can omit strict determination of the line arrangement order when the influence on the interference value is low. Thereby, the amount of calculation can be suppressed.

<Other embodiments>
Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, in the above-described embodiments, the present invention has been mainly described as a hardware configuration. However, the present invention is not limited to this, and a CPU (Central Processing Unit) executes a computer program for arbitrary processing. Can also be realized. In this case, the computer program can be stored and provided to the computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

DESCRIPTION OF SYMBOLS 100 Frequency allocation apparatus 101 Maximum line arrangement | positioning part 102 Line arrangement | positioning order determination part 103 Line arrangement | positioning order memory | storage part 1000 Frequency allocation system 200 DAMA access main apparatus 300 DAMA access subordinate apparatus

Claims (10)

A maximum line placement unit for placing a predetermined number of lines within a given communication frequency band to generate a line set;
A line arrangement order determining unit for determining an assignment order of the lines to a radio station;
A line arrangement order storage unit for storing the assignment order;
The line arrangement order determining unit
A process of calculating a first worst interference value that is the noise level of the line with the smallest difference between carrier power and noise level caused by cross-correlation among the line set;
For each of the lines included in the line set, when the line is temporarily deleted from the line set, the noise level of the line where the difference between the carrier power and the noise level caused by cross-correlation is minimized A process of calculating the worst interference value of 2,
Of the second worst interference value, a line to which the line temporarily deleted when the second worst interference value having the largest difference from the first worst interference value is calculated is to be assigned in a late order. And storing in the line arrangement order storage unit as a frequency arrangement apparatus. The line arrangement order determining unit
A process of deleting the line stored in the line arrangement order storage unit from the line set in the storing process;
Processing for calculating the first worst interference value;
Processing for calculating the second worst interference value;
By repeatedly executing the storing process,
The frequency allocation apparatus according to claim 1, wherein the lines are stored in the line arrangement order storage unit in an order reverse to the order in which lines are assigned to radio stations. The line arrangement order determining unit
If the number of lines present in the line set is below a predetermined threshold,
The frequency arrangement apparatus according to claim 2, wherein the lines existing in the line set are stored in the line arrangement order storage unit in an arbitrary order. A method for determining an assignment order of lines to radio stations,
A maximum line placement step for placing a predetermined number of lines in a given communication frequency band to generate a line set;
Calculating a first worst interference value which is the noise level of a line having a smallest difference between carrier power and a noise level caused by cross-correlation among the line set;
For each of the lines included in the line set, when the line is temporarily deleted from the line set, the noise level of the line where the difference between the carrier power and the noise level caused by cross-correlation is minimized Calculating a worst-case interference value of 2;
Of the second worst interference value, a line to which the line temporarily deleted when the second worst interference value having the largest difference from the first worst interference value is calculated is to be assigned in a late order. Storing in the line arrangement order storage unit as a frequency arrangement method. Deleting the line stored in the line arrangement order storage unit from the line set in the storing process;
Calculating the first worst interference value;
Calculating the second worst interference value;
And further comprising the step of repeatedly executing the storing step,
The frequency arrangement method according to claim 4, wherein the lines are stored in the line arrangement order storage unit in an order reverse to the order in which lines are assigned to radio stations. If the number of lines present in the line set is below a predetermined threshold,
The frequency allocation method according to claim 5, further comprising: storing the lines existing in the line set in the line arrangement order storage unit in an arbitrary order. The program for making a computer perform each step in the method of Claim 4 thru | or 6. A frequency allocation device;
DAMA access main unit;
A DAMA access slave device, and
The frequency allocation device is:
A maximum line placement unit for placing a predetermined number of lines within a given communication frequency band to generate a line set;
A line arrangement order determining unit that determines an allocation order of the lines to the DAMA access slave device;
A line arrangement order storage unit for storing the assignment order;
The line arrangement order determining unit
A process of calculating a first worst interference value that is the noise level of the line with the smallest difference between carrier power and noise level caused by cross-correlation among the line set;
For each of the lines included in the line set, when the line is temporarily deleted from the line set, the noise level of the line where the difference between the carrier power and the noise level caused by cross-correlation is minimized A process of calculating the worst interference value of 2,
Among the second worst interference values, the line arrangement order storage unit stores the line temporarily deleted when the second worst interference value having the largest difference from the first worst interference value is calculated. To store the process,
The DAMA access main unit is:
In response to the request of the DAMA access slave device,
A frequency allocation system that allocates the lines stored in the line allocation order storage unit to the DAMA access slave device in the slowest order. The line arrangement order determining unit
A process of deleting the line stored in the line arrangement order storage unit from the line set in the storing process;
Processing for calculating the first worst interference value;
Processing for calculating the second worst interference value;
By repeatedly executing the storing process,
The line is sequentially stored in the line arrangement order storage unit,
The DAMA access main unit is:
The frequency allocation system according to claim 8, wherein the lines stored in the line allocation order storage unit are allocated to the DAMA access slave device in an order opposite to the order stored in the line allocation order storage unit. The line arrangement order determining unit
If the number of lines present in the line set is below a predetermined threshold,
The frequency arrangement system according to claim 9, wherein the lines existing in the line set are stored in the line arrangement order storage unit in an arbitrary order.

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