JP7287911B2 - Frequency mapping device, frequency mapping method and computer program - Google Patents

Description

The present invention relates to a frequency mapping device, frequency mapping method and computer program.

In recent years, sharing of the same frequency band by different wireless communication systems has been considered to meet the growing demand for mobile traffic. For example, consideration is being given to enabling secondary use of frequency bands allocated to existing wireless communication systems by other wireless communication systems (secondary operator systems). In this frequency sharing between different systems, the secondary operator system uses free resources that are not used by the existing radio communication system that has absolute priority. Non-Patent Documents 1 and 2, for example, describe frequency allocation techniques for allocating a frequency band (shared frequency band) shared by an existing wireless communication system and a secondary operator system to the secondary operator system. The frequency allocation techniques described in Non-Patent Documents 1 and 2 dynamically determine the frequency allocation amount of the shared frequency band on the frequency axis and the time axis based on the demand of the secondary operator system.

“Fair Dynamic Spectrum Management in Licensed Shared Access Systems”, IEEE Systems Journal, Volume: 13, Issue: 3, Sept. 2019 Mirza Kibria, “Resource Allocation in Shared Spectrum Access Communications for Operators with Diverse Service Requirements,” 2016.

However, in the frequency allocation techniques described in Non-Patent Documents 1 and 2, how to map the frequency allocation amount of the shared frequency band allocated to the secondary operator system on the frequency axis and the time axis. has not been considered. Therefore, the following problems may occur.

When the frequencies assigned to the same secondary operator system are separated in the mapping of the frequency allocation amount of the shared frequency band on the frequency axis and the time axis, the number of guard bands between different wireless communication systems increases, resulting in frequency utilization efficiency. decreases. In addition, an increase in the number of component carriers in carrier aggregation (CA) increases resource consumption in base stations and terminals. In addition, if the frequencies assigned to the same secondary operator system are temporally discontinuous, the frequency used by the base station will be switched and the setting will be changed, increasing the number of man-hours required to operate the base station.

The present invention has been made in consideration of such circumstances, and its object is to appropriately distribute the frequency allocation amount of the shared frequency band allocated to each of a plurality of wireless communication systems on the frequency axis and the time axis. is intended to be mapped to

(1) In one aspect of the present invention, a frequency band assigned to an existing wireless communication system and a shared frequency band preferentially used by the existing wireless communication system is different from the existing wireless communication system. In the case of secondary use by a plurality of other secondary-use wireless communication systems, the vacant resources of the shared frequency band that are not used by the existing wireless communication system are allocated to the plurality of secondary-use wireless communication systems. Frequency allocation amount information, which is a frequency mapping device and indicates a frequency allocation amount of the shared frequency band in each time slot not used by the existing wireless communication system assigned to each of the plurality of secondary use wireless communication systems. and an objective function for obtaining the sum of the frequency continuity value and the time continuity value of the allocation channel of each of the secondary use radio communication systems in the mapping calculation period, so that the sum is a mapping calculation unit that obtains frequency channels and time slots of the shared frequency band to be assigned to each of the secondary-use radio communication systems so as to maximize; an allocation result output unit that outputs allocation result information indicating allocation results of frequency channels and time slots , wherein the frequency continuity value is obtained in a certain frequency channel in the same secondary use radio communication system and in the same time slot. The time continuity value calculated by multiplying the mapping result of and the mapping result of the frequency channel shifted by one in the frequency axis direction, in the same secondary use radio communication system and the same frequency channel , is a frequency mapping device calculated by multiplying a mapping result of a certain time slot and a mapping result of a time slot shifted by one in the time axis direction.
(2) In one aspect of the present invention, the frequency allocation amount of the shared frequency band for each of the plurality of secondary-use wireless communication systems is obtained by demand application of each of the plurality of secondary-use wireless communication systems and the existing The frequency mapping device according to (1) above, which is determined for each time slot based on the available resource band on the frequency axis and the available resource time on the time axis in the available resources of the shared frequency band that are not used by the wireless communication system. be.
(3) An aspect of the present invention is any one of (1) or (2) above, wherein the objective function is set with a weighting factor for the frequency continuity value and a weighting factor for the time continuity value. It is a frequency mapping device.
(4) One aspect of the present invention further comprises an allocation result storage unit that stores allocation results of frequency channels and time slots of the shared frequency band allocated to each of the wireless communication systems, wherein the mapping calculation period is the past The frequency mapping apparatus according to any one of (1) to (3) above, wherein the period is included, and the allocation result of the past period is included in the constraints of the mapping calculation period.

(5) In one aspect of the present invention, a frequency band assigned to an existing wireless communication system and a shared frequency band preferentially used by the existing wireless communication system is different from the existing wireless communication system. In the case of secondary use by a plurality of other secondary-use wireless communication systems, the vacant resources of the shared frequency band that are not used by the existing wireless communication system are allocated to the plurality of secondary-use wireless communication systems. A frequency mapping method executed by a frequency mapping device, wherein the frequency mapping device shares the time slots not used by the existing radio communication system assigned to each of the plurality of secondary use radio communication systems. a frequency allocation amount input step of receiving an input of frequency allocation amount information indicating a frequency allocation amount of a frequency band; a mapping calculation step of determining frequency channels and time slots of the shared frequency band to be allocated to each of the secondary-use radio communication systems so that the sum is maximized, using an objective function for determining the sum of time continuity values; an allocation result output step in which the frequency mapping device outputs allocation result information indicating allocation results of frequency channels and time slots of the shared frequency band allocated to each of the secondary use radio communication systems ; The frequency continuity value is obtained by multiplying a mapping result of a certain frequency channel and a mapping result of a frequency channel shifted by one in the frequency axis direction in the same secondary use radio communication system and in the same time slot. The calculated time continuity value is the mapping result of a certain time slot and the mapping result of a time slot shifted by one in the time axis direction in the same secondary use radio communication system and the same frequency channel. It is a frequency mapping method calculated by the product of .

(6) In one aspect of the present invention, a frequency band assigned to an existing wireless communication system and a shared frequency band preferentially used by the existing wireless communication system is different from the existing wireless communication system. In the case of secondary use by a plurality of other secondary-use wireless communication systems, the vacant resources of the shared frequency band that are not used by the existing wireless communication system are allocated to the plurality of secondary-use wireless communication systems. A frequency allocation amount indicating a frequency allocation amount of the shared frequency band in each time slot not used by the existing radio communication system assigned to each of the plurality of secondary use radio communication systems, in a computer of the frequency mapping device. a frequency allocation amount inputting step of accepting input of information; a mapping calculation step of obtaining frequency channels and time slots of the shared frequency band to be assigned to each of the secondary-use radio communication systems so that and an allocation result output step of outputting allocation result information indicating allocation results of frequency channels and time slots , wherein the frequency continuity value is the same as the secondary use radio communication system And in the same time slot, the time continuity value calculated by multiplying the mapping result of a certain frequency channel and the mapping result of the frequency channel shifted by one in the frequency axis direction is the same secondary It is a computer program that is calculated by multiplying a mapping result of a certain time slot and a mapping result of a time slot shifted by one in the time axis direction in the same frequency channel in the wireless communication system used.

ADVANTAGE OF THE INVENTION According to this invention, the effect that the frequency allocation of the shared frequency band allocated to each of several wireless communication systems can be appropriately mapped on a frequency axis and a time axis is acquired.

1 is a block diagram showing a configuration example of a frequency mapping device according to an embodiment; FIG. It is explanatory drawing which shows the comparative example of the mapping result which concerns on one Embodiment, and the conventional mapping result. 4 is a flowchart illustrating an example procedure of a frequency mapping method according to one embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a frequency mapping device according to one embodiment. In FIG. 1 , the frequency mapping device 1 includes a frequency allocation input unit 11 , a mapping calculation unit 12 , an allocation result output unit 13 and an allocation result database (allocation result DB) 14 .

Each function of the frequency mapping device 1 is realized by the frequency mapping device 1 having computer hardware such as a CPU (Central Processing Unit) and memory, and the CPU executing a computer program stored in the memory. be done. The frequency mapping device 1 may be configured using a general-purpose computer device, or may be configured as a dedicated hardware device.

The frequency mapping device 1 performs frequency mapping processing for mapping the frequency allocation amount of the shared frequency band allocated to each of a plurality of wireless communication systems on the frequency axis and the time axis. As an example of the present embodiment, the frequency mapping device 1 uses the frequency band assigned to an existing wireless communication system (existing system) for secondary use by a plurality of other wireless communication systems (secondary operator systems). In this case, the frequency allocation amount of the shared frequency band, in which the free resource of the frequency band (shared frequency band) is allocated to each secondary operator system, is mapped on the frequency axis and the time axis. In this frequency mapping process, in this embodiment, allocation is performed as continuously as possible on the frequency axis and the time axis to the same secondary operator system. As a result, problems such as a decrease in frequency utilization efficiency due to the separation of frequencies allocated to the same secondary operator system, and operational man-hours due to temporal discontinuity in the frequencies allocated to the same secondary operator system We will try to suppress problems such as an increase in

The frequency allocation amount input unit 11 inputs frequency allocation amount information 110 indicating the frequency allocation amount of the shared frequency band of each time slot (time slot) allocated to each of a plurality of wireless communication systems (secondary operator systems). accept. The frequency allocation amount of the shared frequency band to each secondary operator system depends on the demand application of each secondary operator system, the vacancy of the frequency axis (available resource band) and the vacancy of the time axis (available resource band) in the existing system resource time). Hereinafter, the frequency allocation amount of the shared frequency band may be simply referred to as the frequency allocation amount.

The mapping calculation unit 12 maps the frequency allocation amount of each secondary operator system indicated in the frequency allocation amount information 110 onto the frequency axis and the time axis. In this mapping, the mapping calculation unit 12 uses an objective function that obtains the sum of the frequency continuity value and the time continuity value of the allocation channel of each secondary operator system during the mapping calculation period, and maximizes the sum. , the frequency channel and time slot of the shared frequency band to be assigned to each secondary operator system are obtained. The details of this mapping calculation method will be described later.

The allocation result output unit 13 outputs allocation result information 120 indicating the allocation result of the frequency channel and time slot of the shared frequency band allocated to each secondary operator system. The allocation result information 120 of each secondary operator system is notified to each secondary operator system. Each secondary operator system uses the shared frequency band according to its own allocation results indicated in the allocation result information 120 .

The allocation result DB 14 stores allocation results of frequency channels and time slots of the shared frequency band allocated to each secondary operator system.

[Mapping calculation method]
A mapping calculation method according to this embodiment will be described. For example, a subscript "a" may be written as "_a". The frequency mapping device 1 is preset with parameters, objective functions, and constraints used in the frequency mapping process.

The parameters shown in the following equation (1) are set in advance in the frequency mapping device 1 .

i is a secondary operator system number that identifies the secondary operator system. M is a set of secondary operator system numbers. f is a frequency channel number that identifies the frequency channel of the shared frequency band. F is the set of frequency channel numbers of the shared frequency band. t is a time slot number identifying a time slot to which a shared frequency band is assigned. T is a set of time slot numbers. In this embodiment, the set T corresponds to the mapping computation period. This means that all time slot numbers t included in the set T are objects of mapping calculation. α is a weighting factor for frequency continuity. β is a weighting factor for time continuity. x_i, f, t is the mapping result (assignment result) "1 is assigned, 0 is not assigned" in time slot (t) of frequency channel (f) for secondary operator system (i).

In this embodiment, as an example of a value (frequency continuity value) representing the frequency continuity of a channel (assigned channel) allocated to a secondary operator system, a frequency channel allocated to the same secondary operator system within the same time slot Use the number of consecutive Also, as an example of a value representing the time continuity of the allocated channel (time continuity value), the number of consecutive time slots allocated to the same secondary operator system within the same frequency channel is used.

An objective function represented by the following equation (2) is set in advance in the frequency mapping device 1 .

The objective function shown in equation (2) is to find the sum of the frequency continuity value and time continuity value of the assigned channels of each secondary operator system in the mapping calculation period (T). In equation (2), the frequency continuity value is the mapping result x_i, f-1, t of a certain frequency channel (f-1) in the same secondary operator system (i) and in the same time slot (t). It is calculated by multiplying the mapping result x_i, f, t of the frequency channel (f) obtained by shifting the frequency channel (f-1) by one in the frequency axis direction. Also, the time continuity value is the mapping result x_i, f, t-1 of a certain time slot (t-1) and the time slot ( It is calculated by multiplying the mapping result x_i, f, t of the time slot (t) obtained by shifting t−1) by one in the time axis direction.

Further, the objective function represented by the equation (2) can adjust the weighting of the frequency continuity value and the time continuity value by the frequency continuity weighting coefficient α and the time continuity weighting coefficient β. is.

Constraint conditions shown in the following formulas (3), (4), and (5) are set in advance in the frequency mapping device 1 .

(3) is that the total number of frequency channels (f) allocated in a certain secondary operator system (i) and a certain time slot (t) is equal to the secondary operator system (i) and the time slot ( to match the frequency budget fa_i,t for t). The frequency allocation amount fa_i,t for each time slot (t) for the secondary operator system (i) is included in the frequency allocation amount information 110 .

A constraint condition of equation (4) is that the allocation channel of the same frequency channel (f) and the same time slot (t) is allocated only to one secondary operator system (i).

Constraints of expression (5) are that x_i, f, and t are "1: allocated" or "0: not allocated".

The mapping calculation unit 12 finds a solution “mapping result (x_i, f, t)” that satisfies the constraints of formulas (3), (4), and (5) and maximizes the objective function of formula (2). Perform the desired calculation. Conventional optimization tools and search algorithms for solving optimization problems can be applied to this calculation.

Note that the mapping calculation period (T), which is the period for which the objective function of equation (2) is calculated, can be variably set according to requirements such as the calculation time and mapping accuracy for the frequency mapping process. .

Also, the mapping calculation period (T) may be set to include the past time slot (t). If the mapping calculation period (T) includes a past time slot (t), add the mapping result (x_i, f, t) in the past time slot (t) as a constraint. As a result, it is possible to perform mapping in consideration of frequency continuity and time continuity with the mapping result (x_i, f, t) in the past time slot (t). Note that the mapping result (x_i, f, t) for the past time slot (t) is stored in the allocation result DB 14 .

FIG. 2 is an explanatory diagram showing a comparison example between the mapping result according to the present embodiment and the conventional mapping result. FIG. 2(1) shows an example of a conventional mapping result. FIG. 2(2) shows an example of the mapping result of this embodiment.

In the example of the conventional mapping result shown in FIG. 2 (1), frequency continuity and time continuity are not considered in the mapping of the frequency allocation amount, and the frequencies allocated to the same secondary operator system are separated or the same The frequency assigned to the secondary operator system may be discontinuous in terms of time. For this reason, in conventional mapping results, frequency utilization efficiency decreases due to the separation of frequencies assigned to the same secondary operator system, and the frequencies assigned to the same secondary operator system are discontinuous in terms of time. The increase in man-hours required to operate base stations due to

On the other hand, in the example of the mapping result of the present embodiment in FIG. 2 (2), since frequency continuity and time continuity are taken into consideration in the mapping of the frequency allocation amount, the frequencies allocated to the same secondary operator system are separated. Also, the frequencies assigned to the same secondary operator system are suppressed from being discontinuous in terms of time. As a result, the frequencies allocated to the same secondary operator system are separated, resulting in a decrease in frequency utilization efficiency, and the frequency allocation to the same secondary operator system is discontinuous in terms of time, resulting in increased man-hours for operating base stations. It becomes possible to prevent the occurrence of problems such as an increase in

The above is the description of the mapping calculation method according to the present embodiment.

Next, a frequency mapping method according to this embodiment will be described with reference to FIG. FIG. 3 is a flow chart showing an example of the procedure of the frequency mapping method according to this embodiment.

(Step S1) The frequency mapping device 1 receives input of frequency allocation amount information 110 indicating the frequency allocation amount of the shared frequency band of each time slot allocated to each of a plurality of secondary operator systems. Based on the frequency allocation information 110, the frequency mapping device 1 sets each parameter of the above equation (1), the objective function of the above equation (2), and the constraint conditions such as the above equations (3) and (4). .

(Step S2) The frequency mapping device 1 performs a calculation to obtain a solution "mapping result (x_i, f, t)" that satisfies the constraint conditions set in step S1 and maximizes the objective function set in step S1. do.

(Step S3) The frequency mapping device 1 stores the frequency channel and time slot mapping results (x_i, f, t) of the shared frequency band allocated to each secondary operator system obtained in step S2 in the allocation result DB 14. Store.

(Step S4) The frequency mapping device 1 outputs allocation result information 120 indicating the allocation result of the frequency channel and time slot of the shared frequency band allocated to each secondary operator system obtained in step S2.

According to the present embodiment, since frequency continuity and time continuity are considered in the mapping of the frequency allocation amount of the shared frequency band, the frequencies allocated to the same secondary operator system are separated, and the same secondary business Discontinuity in time of the frequency assigned to the user system is suppressed. As a result, it is possible to obtain the effect that the frequency allocation amount of the shared frequency band allocated to each of the plurality of secondary operator systems can be appropriately mapped on the frequency axis and the time axis.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design changes and the like are also included within the scope of the present invention.

Alternatively, a computer program for realizing the functions of the devices described above may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read and executed by the computer system. Note that the “computer system” referred to here may include hardware such as an OS and peripheral devices.
In addition, "computer-readable recording medium" includes writable nonvolatile memories such as flexible discs, magneto-optical discs, ROMs and flash memories, portable media such as DVDs (Digital Versatile Discs), and computer system built-in media. A storage device such as a hard disk that

Furthermore, "computer-readable recording medium" means a volatile memory (e.g., DRAM (Dynamic Random Access Memory)), which holds the program for a certain period of time, is also included.
Further, the above program may be transmitted from a computer system storing this program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in a transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the program may be for realizing part of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program already recorded in the computer system.

DESCRIPTION OF SYMBOLS 1... Frequency mapping apparatus 11... Frequency allocation input part 12... Mapping calculation part 13... Allocation result output part 14... Allocation result database (allocation result DB)

Claims (6)

A plurality of secondary use radio communication systems different from the existing radio communication system in the frequency band assigned to the existing radio communication system and the shared frequency band preferentially used by the existing radio communication system A frequency mapping device that allocates free resources of the shared frequency band that are not used by the existing wireless communication system to the plurality of secondary use wireless communication systems when secondary use is used,
Frequency allocation for accepting input of frequency allocation amount information indicating a frequency allocation amount of the shared frequency band in each time slot not used by the existing radio communication system allocated to each of the plurality of secondary use radio communication systems. an amount input unit;
Using an objective function for calculating the sum of the frequency continuity value and the time continuity value of the allocated channel of each of the secondary use wireless communication systems in the mapping calculation period, each of the secondary uses is calculated so that the sum is maximized. a mapping calculation unit for obtaining frequency channels and time slots of the shared frequency band to be allocated to a wireless communication system;
an allocation result output unit that outputs allocation result information indicating allocation results of frequency channels and time slots of the shared frequency band allocated to each of the secondary use radio communication systems;
with
The frequency continuity value is obtained by multiplying a mapping result of a certain frequency channel and a mapping result of a frequency channel shifted by one in the frequency axis direction in the same secondary use radio communication system and in the same time slot. calculated,
The time continuity value is obtained by multiplying the mapping result of a certain time slot and the mapping result of a time slot shifted by one in the time axis direction in the same secondary use radio communication system and the same frequency channel. calculated,
Frequency mapping device. The frequency allocation amount of the shared frequency band for each of the plurality of secondary-use wireless communication systems is calculated based on the demand application of each of the plurality of secondary-use wireless communication systems and the shared frequency band not used by the existing wireless communication system. Determined for each time slot based on the free resource band on the frequency axis and the free resource time on the time axis in the free resource of the frequency band,
The frequency mapping device according to claim 1. In the objective function, a weighting factor for the frequency continuity value and a weighting factor for the time continuity value are set.
3. A frequency mapping device according to claim 1 or 2. further comprising an allocation result storage unit that stores allocation results of frequency channels and time slots of the shared frequency band allocated to each of the secondary use radio communication systems;
the mapping calculation period includes a past period;
the allocation results of the past period are included in the mapping calculation period constraints;
A frequency mapping device according to any one of claims 1 to 3. A plurality of secondary use radio communication systems different from the existing radio communication system in the frequency band assigned to the existing radio communication system and the shared frequency band preferentially used by the existing radio communication system A frequency mapping method executed by a frequency mapping device that allocates free resources of the shared frequency band that are not used by the existing wireless communication system to the plurality of secondary use wireless communication systems when secondary use is performed by can be,
frequency allocation amount information indicating the frequency allocation amount of the shared frequency band in each time slot not used by the existing radio communication system assigned to each of the plurality of secondary use radio communication systems by the frequency mapping device; A frequency allocation amount input step for accepting input of
The frequency mapping device uses an objective function for obtaining the sum of the frequency continuity value and the time continuity value of the allocated channel of each of the secondary use radio communication systems in the mapping calculation period, so that the sum is maximized. , a mapping calculation step for obtaining frequency channels and time slots of the shared frequency band to be allocated to each of the secondary-use radio communication systems;
an allocation result output step in which the frequency mapping device outputs allocation result information indicating allocation results of frequency channels and time slots of the shared frequency band allocated to each of the secondary use radio communication systems;
including
The frequency continuity value is obtained by multiplying a mapping result of a certain frequency channel and a mapping result of a frequency channel shifted by one in the frequency axis direction in the same secondary use radio communication system and in the same time slot. calculated,
The time continuity value is obtained by multiplying the mapping result of a certain time slot and the mapping result of a time slot shifted by one in the time axis direction in the same secondary use radio communication system and the same frequency channel. calculated,
Frequency mapping method. A plurality of secondary use radio communication systems different from the existing radio communication system in the frequency band assigned to the existing radio communication system and the shared frequency band preferentially used by the existing radio communication system In the case of secondary use, the computer of the frequency mapping device that allocates the free resources of the shared frequency band that are not used by the existing wireless communication system to the plurality of secondary use wireless communication systems,
Frequency allocation for accepting input of frequency allocation amount information indicating a frequency allocation amount of the shared frequency band in each time slot not used by the existing radio communication system allocated to each of the plurality of secondary use radio communication systems. a quantity input step;
Using an objective function for calculating the sum of the frequency continuity value and the time continuity value of the allocated channel of each of the secondary use wireless communication systems in the mapping calculation period, each of the secondary uses is calculated so that the sum is maximized. a mapping calculation step of determining frequency channels and time slots of the shared frequency band to be allocated to a wireless communication system;
an allocation result output step of outputting allocation result information indicating allocation results of frequency channels and time slots of the shared frequency band allocated to each of the secondary use radio communication systems;
A computer program for executing
The frequency continuity value is obtained by multiplying a mapping result of a certain frequency channel and a mapping result of a frequency channel shifted by one in the frequency axis direction in the same secondary use radio communication system and in the same time slot. calculated,
The time continuity value is obtained by multiplying the mapping result of a certain time slot and the mapping result of a time slot shifted by one in the time axis direction in the same secondary use radio communication system and the same frequency channel. calculated,
computer program.

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