KR101145204B1 - Transmitting power control device and method of sector antenna system - Google Patents

Abstract

An apparatus for controlling transmission power of a sector antenna system according to the present invention includes a transmission power calculating unit for calculating transmission power required for communication from the base station to a terminal station for each sector antenna forming an antenna of the base station, and the calculated transmission power. It includes a transmission power alignment unit for aligning according to size of each sector antenna and allocating frequency channels to the aligned transmission powers in order, and adjusting transmission power for each frequency channel in some cases. By reducing co-channel interference between antennas to improve C / I, the result is improved frequency utilization and improved radio link quality.

Description

Transmission power control apparatus and method of sector antenna system {TRANSMITTING POWER CONTROL DEVICE AND METHOD OF SECTOR ANTENNA SYSTEM}

The present invention relates to an apparatus and method for controlling transmission power of a sector antenna system, and more particularly, to reduce interference between adjacent channels and interference between symmetric sector antennas and improve carrier-to-interference ratio in a communication system using a sector antenna. An apparatus and method for controlling transmission power of a sector antenna system are provided.

In general, point-to-multipoint systems use frequency reuse techniques through sectorization to increase transmission capacity and increase the number of users in the limited frequency band.

In order to eliminate interference by side-lobes between adjacent sectors during sectorization using a sector antenna, a method of fundamentally separating channels by using orthogonal channels (time, frequency, code, polarization, etc.) is common. Used as Interference between the front sector and the back sector, which form a symmetrical sector in the same cell, is caused by back-lobes, and its effect is smaller than that of the side lobe. It can be solved. Interference between adjacent frequency channels in the same sector is caused by filter characteristics and can be reduced through guard bands.

When transmitting a radio signal at the same frequency in each symmetric sector, the back lobe radiation propagation of the signal transmitted in one sector acts as an unwanted interference signal for the symmetric sector. The signal-to-noise ratio that can be obtained when the base station receives the base station signal depends on the front and rear gain ratio of the sector antenna. As the transmission distance or speed required by the user increases, the required radio transmission output value increases, and as a result, the size of the back lobe signal increases. Since the back lobe signal acts as an interference signal on the same frequency channel in the symmetrical sector, it is a major factor that inhibits the carrier-to-interference ratio (C / I) for the small output signal.

Although the channel can be separated by using the orthogonal channel as a method of eliminating such interference, there is a problem that the frequency utilization is significantly reduced. In addition, when the output signal difference between adjacent frequency channels becomes larger, changes such as designing a guard band wider or adjusting the output at the base station are required to reduce interference between channels.

The present invention provides an apparatus and method for controlling transmission power of a sector antenna system capable of reducing interference between adjacent frequency channels and interference between symmetrical sectors and improving carrier-to-interference ratio (C / I) through adjustment / control of transmission power. It is to.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. Other objects, which will be apparent to those skilled in the art, It will be possible.

The transmission power control apparatus of the sector antenna system of the present invention for achieving the above object is a transmission power calculation unit for calculating the transmission power required for communication from the base station to the terminal station for each sector antenna of the base station and the calculated transmission power It may include a transmit power alignment unit for aligning according to the size for each sector antenna, and allocates frequency channels in order to the aligned transmit power.

In this case, when the difference between the larger transmission power adjacent to each of the aligned transmission powers and the aligned transmission power exceeds the adjacent channel threshold value, the adjacent transmission power within a range not exceeding an allowable frequency channel number. And an adjacent channel transmission power adjustment unit inserting and adjusting an extra channel between the aligned transmission powers. Here, the number of extra channels may be calculated by the following equation.

Number of spare channels = [((adjacent transmit power-transmit power)-1) / adjacent channel threshold]

Where [] is a Gaussian function symbol.

The adjacent channel transmit power adjusting unit may adjust the aligned transmit powers upwardly so that the difference in power satisfies the adjacent channel threshold value after the redundant channel is formed, when the difference in power exceeds the adjacent channel threshold value. have.

Further, if the difference between the larger transmit adjacent power and each aligned transmit power among the aligned transmit powers exceeds the adjacent channel threshold, the alignment is such that the difference in power satisfies the adjacent channel threshold. The apparatus may further include an adjacent channel transmission power adjusting unit configured to upwardly adjust each transmitted power.

In this case, the adjacent channel transmission power adjusting unit may perform the upward adjustment from the transmission power adjacent to the adjacent transmission power having the largest value among the aligned transmission powers.

Further, if the number of sector antennas is arranged in four or more even numbers, and the difference in transmission power between symmetric sector antennas of each sector antenna in the same channel among the allocated channels exceeds the same channel threshold, the same channel threshold is satisfied. The apparatus may further include a co-channel transmit power adjusting unit configured to upwardly adjust a transmit power of a smaller value among the transmit powers of the symmetric sector antenna.

Further, if the sector antennas are arranged in four or more even numbers, and after adjustment in the adjacent channel transmission power adjusting unit, if the difference in transmission power between symmetric sector antennas of each sector antenna in the same channel exceeds the same channel threshold, The apparatus may further include an co-channel transmit power adjusting unit configured to upwardly adjust the transmit power of a smaller value among the transmit powers of the symmetric sector antenna to satisfy the co-channel threshold.

In addition, the alignment performed in the transmission power alignment unit may be one of an ascending sort, a descending sort, and a center sort.

On the other hand, the transmission power control method of the sector antenna system of the present invention calculates the transmission power required for communication from the base station to the terminal station for each sector antenna of the base station and the calculated transmission power to each sector antenna size And assigning frequency channels in order to the sorted transmit powers.

In this case, after the allocating step, a range not exceeding an allowable frequency channel number such that a difference between a large neighboring transmit power among the aligned transmit powers adjacent to each of the aligned transmit powers and the aligned transmit powers does not exceed an adjacent channel threshold value. And inserting or adjusting an extra channel between the adjacent transmit power and the aligned transmit power within each other, or adjusting the aligned transmit power upwards.

Further, the sector antennas are arranged in four or more even numbers, and after the assigning step, the difference in transmission power between symmetric sector antennas of each sector antenna in the same channel of the allocated channels does not exceed the same channel threshold. The method may further include adjusting the transmit power of a smaller value among the transmit powers of the symmetric sector antenna.

Further, the sector antennas are arranged in four or more even numbers, and after the allocating step, the difference between each of the larger transmit powers adjacent to the aligned transmit powers and the aligned transmit powers is a neighbor channel threshold. Inserting or adjusting an extra channel between the adjacent transmit power and each aligned transmit power within a range not exceeding an allowable frequency channel number so as not to exceed or adjusting up each of the aligned transmit powers and after the adjusting The method may further include adjusting the transmit power of a smaller value of the transmit power of the symmetric sector antenna so that a difference in transmit power between the symmetric sector antennas of each sector antenna in the same channel does not exceed an equal channel threshold.

As described above, the apparatus and method for controlling transmission power of a sector antenna system according to the present invention allocates adjacent channels by allocating frequency channels in a state in which the transmission power required for communication from each sector antenna to a predetermined terminal station is arranged in order of magnitude. The interference between the antennas and the symmetrical sector antennas can be reduced. This can also improve the carrier-to-interference ratio.

In addition, interference between adjacent channels can be minimized by performing adjustment to insert an extra channel between adjacent channels after alignment, or adjusting up a small value of transmission power (value) in the adjacent channel.

Likewise, by adjusting up the relatively low transmit power in the symmetric sector antenna after alignment, it is possible to minimize the interference between the symmetric sector antennas and improve the carrier-to-interference ratio more reliably.

1 is a block diagram showing a transmission power control apparatus of a sector antenna system according to the present invention.
2 is a schematic diagram showing the jurisdiction when four sector antennas are arranged;
3 is a flowchart illustrating a transmission power control method of a sector antenna system according to the present invention;

Hereinafter, an apparatus and method for controlling transmission power of a sector antenna system according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a transmission power control apparatus of a sector antenna system according to the present invention.

The apparatus for controlling transmission power of the sector antenna system shown in FIG. 1 includes a transmission power calculating unit 110 for calculating transmission power required for communication from the base station to the terminal station for each sector antenna that is an antenna component of the base station, and the calculated transmission. And a transmission power alignment unit 130 for aligning power according to sizes of the sector antennas and allocating frequency channels in order to the aligned transmission powers.

Sector antennas are used in systems to increase transmission capacity and increase the number of users in limited frequency bands. For example, arranging four antennas with a 90 degree directivity can cover more users than using one omnidirectional antenna. In this case, each of the arrayed antennas becomes a sector antenna, and the sector antenna may be installed in the base station.

The transmission power calculating unit 110 calculates transmission power required for communication with the terminal station corresponding to the user (usually communicating with the sector antenna through the directional antenna) for each sector antenna. In order to calculate the transmission power, distance, direction and link speed information between the base station equipped with the sector antenna and the terminal station is utilized. In some cases, transmission power can be calculated by transmitting and receiving test radio waves. In the former case, reference may be made to the information of the network planning means for setting the network plan including the identifier, location, and link speed information of the terminal station.

Conventionally, a frequency channel is assigned to the calculated transmission power, and the frequency of the allocated channel is transmitted at the corresponding transmission power.

For example, when the antenna of the base station is formed as four sector antennas having a 90-degree directivity, as shown in FIG. 2, sector A, which is the jurisdiction of sector antenna A, sector B, which is the jurisdiction of sector antenna B, and jurisdiction of sector C, as shown in FIG. Four sectors are formed as sectors, sector D, which is a jurisdiction of sector antenna D. At this time, sector antennas A and C are symmetrical sector antennas, and B and C are symmetrical sector antennas.

 When there are eight terminal stations in the sector antenna A jurisdiction (Sector A) and eight terminal stations in the sector antenna C jurisdiction (Sector C), the frequency channel may be allocated as in the transmission power misalignment state of Table 1 below.

In the transmission power misalignment state, which shows an example of the existing frequency allocation, the terminal station 1 requiring 12 dBm transmission power in the sector A, the terminal station 2 requiring 4 dBm transmission power, and the terminal station requiring 8 dBm transmission power 3 and 20 dBm Station stations 4 requiring 5 dBm transmit power, 5 stations requiring 5 dBm transmit power, 6 stations requiring 6 dBm transmit power, 6 stations requiring 10 dBm transmit power, and 9 stations requiring 9 dBm transmit power. In this case, the frequency channels of F1, F2, ..., F8 are allocated in random order without applying any special rules to the allocation of frequency channels. The frequency assignment without special rules is similarly made for the terminal station in the sector C.

The carrier-to-interference ratio (C / I) received by each terminal station is determined by Equation 1 below.

For example, if the front and rear gain ratio of the sector antenna is 25dB, the C / I of the terminal station using the F1 channel in sector A is 12dBm-9dBm + 25dB = 28dB. In addition, the C / I of the station using the F1 channel in the sector C is 9dBm-12dBm + 25dB = 22dB. Through this process, each station C / I of sector A is 28dB, 6dB, 26dB, ..., 17dB per channel, and each station C / I of sector C is 22dB, 44dB, 24dB, ... , 33 dB. In particular, it can be seen that the C / I of the terminal station using the F2 and F5 channels of the sector A is significantly low at 6dB and 2dB. C / I Low C / I, such as 6dB and 2dB, is due to interference from symmetrical sector antennas, resulting in unsuitable communications.

In addition, since the station C / I of the sector A is equal to 28 dB, 6 dB, 26 dB,..., The interference of adjacent channels is caused due to the large power difference between adjacent channels.

In order to improve the C / I of the terminal station, it is necessary to reduce the interference between the adjacent channel and the interference between the symmetrical sector antennas, and the transmit power alignment unit 130 is used for this purpose.

The transmission power aligning unit 130 sorts the transmission powers calculated by the transmission power calculating unit according to the size of each sector antenna and allocates frequency channels in the sorted order.

In this case, the sorting may be one of an ascending sort, a descending sort, and a central sort. As an example, the case using ascending sorting is shown in Table 1 (state after sorting of transmit power). In descending order, the order is reversed from Table 1. In the case of the center sort, the largest number is placed in the center, and the smaller number is arranged alternately left and right around the largest number.

Referring to Table 1 (state after the transmission power alignment), the transmission powers are sorted in ascending order such as 4 dBm, 5 dBm, 6 dBm, ..., 20 dBm of the sector A, and frequency channels F1 to F8 are allocated according to the sorting order. That is, the channel F1 is allocated to the terminal station 2 having the existing 4dBm transmission power instead of the channel F2.

In the case of the sector C, ascending order is shown as 7dBm, 9dBm, 11dbBm, ..., 28dBm. Accordingly, C / I is 22dB, 21dB, 20dB, ..., 17dB for each channel in A sector and 28dB, 29dB, 30dB, ..., 33dB for each channel in C sector. Overall, the C / I is improved compared to the C / I in the transmission power misalignment state, and the C / I is improved.

In addition, it can be seen that the difference in transmission power between adjacent channels in the same sector is also reduced, thereby reducing interference between adjacent channels. That is, if the transmit power alignment unit aligns the transmit power according to the size of each sector antenna and allocates the frequency channels according to the sorted order, the C / I is improved and the interference between adjacent channels and the interference between symmetrical sector antennas are reduced. .

Hereinafter, a method of further improving C / I and further reducing interference between adjacent channels and interference between symmetric sector antennas by adjusting the transmission powers aligned in the transmission power alignment unit according to a predetermined rule.

In the foregoing, the alignment through the transmit power alignment unit improves the C / I and reduces the interference between adjacent channels and the interference between symmetrical sector antennas. Despite such an alignment, there may be interference between adjacent channels and desired May not satisfy C / I.

For example, when the adjacent channel threshold value, which is the allowable difference in transmit power between channels, is 4 dB, the difference in transmit power between adjacent channels should be 4 dB or less. However, in Table 1, the difference in transmit power between adjacent channels is reduced through the alignment, but the power difference between F7 and F8 is 8dB in sector A, and the power difference between F7 and F8 in sector C is 5dB, which exceeds 4dB of adjacent channel threshold. Able to know. This state is a state in which interference may still exist between adjacent channels in the same sector.

As such, the adjacent channel transmission power adjusting unit 150 may be further included to minimize interference between adjacent channels that may occur even after the alignment.

The adjacent channel transmission power adjusting unit 150 adjusts the insertion of an extra channel between the adjacent channels or adjusts the transmission power upward so that the difference in the transmission power between the adjacent channels satisfies the adjacent channel threshold. As a result, the adjacent channel transmit power adjustment unit suppresses interference between adjacent channels.

First, a method of using upward adjustment of the transmission power will be described.

The adjacent channel transmission power adjusting unit 150 adjusts each of the aligned transmission powers so that the difference in power satisfies the adjacent channel threshold when the difference between each aligned transmission power and the adjacent transmission power exceeds the adjacent channel threshold. Each transmit power aligned within the same sector has two adjacent transmit powers (the leftmost and rightmost transmit powers have one adjacent transmit power). In this case, a transmission power having a larger value among two adjacent transmission powers will be referred to as an adjacent transmission power. For example, in Table 1, when looking at the sector A in the aligned state, the transmit power is arranged as 4, 5, 6, 8, 9, 10, 12, 20 dBm. At this time, the transmission power adjacent to 5dBm becomes 4dBm and 6dBm, and 6dBm having a larger value becomes adjacent transmission power. Therefore, when the adjacent channel threshold is 4 dB, the difference between the transmit power of 5 dBm of the F2 channel and the adjacent transmit power of 6 dBm of the F3 channel is 6-5 = 1 dB, which is less than or equal to the adjacent channel threshold, so that the upward adjustment of the transmit power of the F2 channel needs to be applied. none. In the case of the transmission power of 12 dBm of the F7 channel, since the adjacent transmission power is 20 dBm of the transmission power of the F8 channel, an upward adjustment needs to be applied because 20-12 = 8 exceeds the adjacent channel threshold. The degree of upward adjustment should be such that it satisfies the adjacent channel threshold. Simply increase the transmit power so that the difference in power is equal to the adjacent channel threshold. In other words, add 8dB of power difference-4dB = 4dB of adjacent channel threshold to 12dBm. In other words, increase the transmit power of 12dBm on the F7 channel to 16dBm. You can add a value larger than 4 dB, but you will have to accept additional power loss above 4 dB.

Since the transmit power of the F7 channel has been adjusted to 16 dBm, the transmit power of the F6 channel, which uses the transmit power of the F7 channel as the adjacent transmit power, must also be adjusted upward from the original 10 dBm to x = 12 dBm to satisfy 16 dBm-x dBm = 4 dB. . In Table 1, since the transmit power of the F8 channel is adjusted to 23 dBm, the transmit power of the F7 channel is also adjusted to 19 dBm instead of 16 dBm, which will be described later to suppress interference between symmetrical sector antennas.

The upward adjustment discussed above does not have any problem from any channel. However, it is preferable to perform upward adjustment from the channel having the largest transmission power as the adjacent transmission power in the same sector to the channel of the gradually lower transmission power. For example, if the transmit power of the F7 channel is adjusted upward while the transmit power is adjusted upward with the F7 channel as the adjacent transmit power, the transmit power of the F6 channel is changed to the transmit power of the F7 channel as the adjacent transmit power. Should be adjusted upward. That is, since redundancy calculation may be performed, it is preferable to perform upward adjustment from the transmission power adjacent to the largest transmission power of each of the aligned transmission powers in order to prevent this.

In the case where the adjacent channel threshold is satisfied using the upward adjustment of the transmission power, it is not necessary to further perform the scheme using the redundant channel described below.

A method of using a redundant channel so that a difference between adjacent transmission powers satisfies an adjacent channel threshold is described.

The adjacent channel transmission power adjusting unit 150 provides an extra channel between the adjacent transmission power and each transmission power within a range not exceeding the allowable frequency channel number when the difference between the adjacent transmission power and each transmission power exceeds the adjacent channel threshold. Adjust insertion. That is, when the difference between adjacent transmission power and each transmission power exceeds an adjacent channel threshold, interference between adjacent channels can be reduced by inserting an extra channel between the adjacent transmission power (channel) and the transmission power (channel). have.

For example, assuming that there are five terminal stations in sector A and seven terminal stations in sector C, the transmission power for each terminal station is shown in Table 2. It is assumed that the front and rear gain ratio of the sector antenna is 25 dB, the adjacent channel threshold is 4 dB, and the same channel threshold is 5 dB.

F1 to F8 channels in sector A are 9dBm, 6dBm, 5dBm, 30dBm, 4dBm unsorted transmit power in Table 2, and the channels of sector C are 23dBm, 11dBm, 15dbBm ,. At 14dBm, the transmit power is also not aligned. C / I of each terminal station in sector A is 9dB, 20dB, 15dB, 37dB, 22dB, and C / I of each terminal in sector C is 39dB, 30dB, 35dB, ..., 39dB. It can be seen that the C / I of the UE using the F1 channel in the sector A is 9 dB.

In the state after the transmit power alignment of Table 2, the F1-F8 channels of the sector A are arranged in ascending order of 4dBm, 5dBm, 6dBm, 9dBm, and 30dBm. The channels in sector C are also arranged in ascending order: 7 dBm, 9 dBm, 11 dbBm, ..., 23 dBm, and so on. As a result, C / I is 22dB, 21dB, 20dB, 20dB, 17dB for each channel in A sector, and 28dB, 29dB, 30dB, ..., 48dB for each channel in C sector. It can be seen that the C / I is improved by sorting the transmission power according to the size and then distributing the channels according to the sorting order. However, there may still be a low value of C / I, such as C / I of C sector terminal station of F5 channel is 10dB. This is because the difference between the F5 channel transmit power of the sector A and the F5 channel transmit power of the sector C is 15 dB, which greatly exceeds the allowable transmission difference between the sectors (the same channel threshold value) of 5 dB. In addition, the transmission power difference between the F4 and F5 channels of the same sector A is 21dB, which greatly exceeds the adjacent channel threshold value of 4dB between channels. In this case, the interference between adjacent channels can be minimized through the above-described upward adjustment, but the influence of the interference can be minimized by inserting and adjusting unused frequency channels (extra channels).

In the state after the adjustment of the extra channel insertion in Table 2, an appropriate number of extra channels, which are unused frequency channels, are inserted between channels in which a power difference exceeding the adjacent channel threshold is calculated.

The number of extra channels inserted to minimize interference of adjacent channels can be calculated by the following equation.

Where [] is a Gaussian function symbol (choose the largest value of the same or smaller integer).

For example, since the difference between frequency channels F5 and F4 in sector A is 21 dB (= 30-9), it is preferable that five extra channels (= [(21-1) / 4]) are inserted. However, since the number of allowable frequency channels is eight, when five extra channels are inserted, it is impossible to add up to five existing channels, resulting in a total of ten channels. Therefore, three spare channels are inserted to satisfy the number of allowable frequency channels. As a result, the transmit power of the F5 channel is pushed to the F8 channel to be allocated. The F5, F6, and F7 channels are redundant channels and do not have transmit power. Since the power difference between frequency channels F7 and F6 in sector C is 6 dB, one redundant channel (= [(6-1) / 4]) is inserted, and as a result, the transmit power of channel F7 is allocated to F8. The F7 channel is a redundant channel and there is no transmit power.

Looking at the C / I in this state, it can be seen that it is greatly improved.

However, all or part of it may be impossible since the insertion of the extra channel is limited by the number of allowable frequency channels. Accordingly, since there may exist channels having a transmission power exceeding the adjacent channel threshold even after the insertion of the redundant channel, the above-described upward adjustment may be performed after the insertion adjustment of the redundant channel. That is, the adjacent channel transmit power adjusting unit may adjust each transmit power upward so that the difference in power satisfies the adjacent channel threshold if the difference in adjacent transmit power exceeds the adjacent channel threshold even after forming an extra channel.

In the above, the transmission power is sorted in order of magnitude, and then the channel is allocated, the aligned transmission power is adjusted upward, or an extra channel is inserted between the adjacent channels to reduce interference between adjacent channels and improve C / I. We looked at

Analysis of Equation 1 shows that the transmission power difference between symmetrical sector antennas should be considered to improve C / I more reliably.

Since the base station antenna is formed by arranging a plurality of sector antennas at equal intervals, even sector antennas are required to form a symmetric sector antenna. In addition, when there are two sector antennas, there is no meaning of a symmetric sector antenna. Therefore, it is assumed that the base station antenna described below is formed of four or more even sector antennas. The base station antenna may be formed of a large number of sector antennas, but the durability of components supporting the sector antennas may be formed of sector antennas within 16 ranges in consideration of the distance between the sector antennas.

In the state after adjusting the transmit power of Table 1, it was mentioned that the transmit power of the F8 channel of the sector A was adjusted upward from 20 dBm to 23 dBm. This is a result of adjusting the F8 channel of sector A upward so that the difference in transmit power between symmetrical sector antennas satisfies the same channel threshold.

If the difference in the transmission power between the symmetrical sector antenna is more than according to Equation 1, normal communication is impossible. Therefore, it is necessary to make sure that the difference in transmission power between each symmetric sector antenna satisfies the same channel threshold value that is the power difference in which normal communication is possible. For this purpose, the same channel transmission power adjusting unit 170 may be included.

The co-channel transmit power adjusting unit 170, if the difference in transmit power between the symmetric sector antennas in the same channel among the channels allocated by the transmit power alignment unit 130 exceeds the same channel threshold, the symmetric sector antenna to satisfy the same channel threshold The transmission power of the smaller value of the transmission power of the up is adjusted. That is, the co-channel transmit power adjuster may be included in the transmit power control apparatus of the sector antenna system without the adjacent channel transmit power adjuster 150.

For example, if the same channel threshold, which is the transmit power tolerance between sectors, is 5 dB in the state after the transmit power alignment in Table 1, the difference between the transmit power of 20 dBm of the A-sector F8 channel and the transmit power of 28 dBm of the C-sector F8 channel is 8 dB. The value exceeds 5 dB. Therefore, the transmit power of the A-sector F8 channel is increased by 20dBm by 8-5 = 3dB, and as a result, the transmit power of the A-sector F8 channel is 23dBm. If this process is performed for each channel, the same channel threshold can be satisfied for all channels, and as a result, C / I is improved.

However, when only the same channel transmit power adjuster is included in the absence of the adjacent channel transmit power adjuster, interference between the symmetrical sector antennas and C / I can be reliably improved, but there may be a problem of interference between adjacent channels. On the contrary, when only the adjacent channel transmit power adjuster is included in the absence of the same channel transmit power adjuster, interference between adjacent channels is reliably suppressed, but there may be a problem in reliably improving interference between C / I and the same channel. Of course, both problems are largely solved by the alignment performed in the transmission power alignment unit, but may include both the adjacent channel transmission power adjustment unit and the same channel transmission power adjustment unit to improve the reliability thereof.

When the transmission power control apparatus of the sector antenna system includes both the adjacent channel transmission power adjusting unit 150 and the same channel transmission power adjusting unit 170, the base station antennas are configured to have four or more even sector antennas to drive the same channel transmission power adjusting unit. It should be formed as

It is also possible to drive the co-channel transmit power adjuster first and then the adjacent channel transmit power adjuster and vice versa.

Specifically, a case in which the adjacent channel transmit power adjuster is driven first will be described. After the adjustment is performed in the adjacent channel transmit power adjuster, the difference in transmit power between the symmetric sector antennas of each sector antenna in the same channel is equal to the threshold of the same channel. If the value is exceeded, the transmit power of a smaller value among the transmit powers of the symmetric sector antenna is adjusted upward to satisfy the same channel threshold.

For example, assuming that there is a sector antenna A, a sector antenna C that are symmetrical to each other, and that the adjacent channel threshold is 4 dBm and the same channel threshold is 5 dBm, the transmit power in the state where the adjacent channel transmit power adjuster is driven is shown in Table 1. As follows. If the adjustment is made based on the transmit power of the F7 channel, 4, 5, 6, 8, 9, 10, 12, and 20 in the aligned state are 4, 5, 6, 8, 9, 12, and 16 for sector A. , 20. In the case of sector C, 7, 9, 11, 14, 17, 20, 23, 28 in the aligned state becomes 7, 9, 11, 14, 17, 20, 24, 28.

In this state, when the same channel transmission power adjusting unit is driven, since a small value is adjusted upward in the same channel, the sector A is 4, 5, 6, 9, 12, 15, 19, 23, and the sector C remains as it is.

If the co-channel transmission power control unit is driven first, 4, 5, 6, 8, 9, 10, 12, and 20 in the aligned state become 4, 5, 6, 9, 12, 15, 18, and 23 for sector A. , Sectors C are 7, 9, 11, 14, 17, 20, 23, 28 in the aligned state.

In this state, when the adjacent channel transmit power adjusting unit is driven, the sector A becomes 4, 5, 6, 9, 12, 15, 19, 23, and the sector C has 7, 9, 11, 14, 17, 20, 24, 28.

3 is a flowchart illustrating a method of controlling a transmit power of a sector antenna system according to the present invention, and may be described as an operation of the apparatus for controlling transmit power of the sector antenna system shown in FIG. 1.

First, the transmission power required for communication from the base station to the terminal station for each sector antenna forming the antenna of the base station is calculated (S510). The transmission power is calculated by the transmission power calculating unit 110 and may use the information of the network planning means or calculate the transmission power by using test radio waves as necessary.

The calculated transmit powers are sorted according to sizes of the sector antennas, and frequency channels are sequentially allocated to the sorted transmit powers (S520). The transmission power alignment unit 130 may be performed to suppress interference between adjacent channels as a whole and improve C / I.

After such alignment and channel assignment, steps for more reliably suppressing interference between adjacent channels and improving C / I may be added.

In order to reliably suppress the interference between adjacent channels, the allowable frequency such that a difference between the larger transmission power adjacent to each of the aligned transmission powers and each aligned transmission power does not exceed the adjacent channel threshold (S530). Within a range not exceeding the number of channels, an extra channel may be inserted and adjusted between the adjacent transmission power and each of the aligned transmission powers (S540) or the adjusted transmission powers may be adjusted upward (S560). After the insertion adjustment, the upward adjustment may be performed as necessary. The operation performed by the adjacent channel transmission power adjusting unit according to the upward adjustment shows that a difference in transmission power between adjacent channels in all channels satisfies the adjacent channel threshold. Nevertheless, it is determined whether the spare channel can be inserted (S540) and the insertion adjustment (S550) is because the power consumption is lower than that of the uplink adjustment. According to the upward adjustment, interference between adjacent channels can be reliably suppressed, but unnecessary power may be wasted because power greater than the transmit power calculated by the transmit power calculator is used. In consideration of this, it is preferable to apply a method of inserting and adjusting an extra channel first, and then apply an upward adjustment.

To further improve C / I, the power difference between symmetrical sector antennas can be adjusted to meet the same channel threshold. An operation performed by the co-channel transmit power adjusting unit, in which a base station antenna formed of four or more even-numbered sector antennas is provided, in which a difference in transmit power between symmetric sector antennas of each sector antenna is the same in the same channel among the allocated channels. The transmit power of a smaller value of the transmit powers of the symmetric sector antennas may be adjusted upward so as not to exceed the channel threshold (S 570) (S 580).

Only one uplink adjustment for C / I improvement and uplink / insertion adjustment for suppressing interference between adjacent channels may be performed or may be performed together. When performed together, the up-and-down relationship may be performed first for up-to-date adjustment for improving C / I and up-down / insertion adjustment for suppressing interference between adjacent channels may be performed first. In the latter case, the difference between the larger transmit power adjacent to each of the aligned transmit powers and the aligned transmit powers is adjacent to each other when the base station antenna is formed of four or more even sector antennas. Insertion or adjustment of an extra channel between the adjacent transmit power and each aligned transmit power within a range not exceeding an allowable frequency channel number so as not to exceed a threshold value, or upward adjustment of each aligned transmit power, and the adjustment Thereafter, in the same channel, the transmit power of the smaller of the transmit powers of the symmetric sector antennas is adjusted upward so that the difference in transmit power between the symmetric sector antennas of each sector antenna does not exceed the same channel threshold.

For reference, the final transmission power controlled by the transmission power control apparatus of the sector antenna system according to the present invention may be in various forms. For example, as shown in FIG. 1, the transmission power ① aligned in the transmission power alignment unit 130 may be the final transmission power. Also, the final transmission power may be the transmission power ② further adjusted by the adjacent channel transmission power adjusting unit. Also, the final transmission power may be the transmission power ③ further adjusted by the same channel transmission power adjusting unit. In addition, after the adjustment is performed in the adjacent channel transmission power adjusting unit, the transmission power ④ adjusted again in the same channel transmission power adjusting unit may be the final transmission power. The reverse transmission power ⑤ may also be the final transmission power.

On the other hand, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

For example, Table 1 and Table 2 show the sorted state in ascending order, but can also be applied to the sorted state in descending order or the center sorted state.

It can be applied to the control of the transmission power in the sector antenna system.

In addition, the present invention can be applied to a system for improving C / I by suppressing interference between adjacent channels and suppressing interference between symmetrical sector antennas.

110 Transmitting power calculation unit 130 Transmitting power alignment unit
150 ... Adjacent Channel Transmit Power Adjuster 170 ... Same Channel Transmit Power Adjuster

Claims (13)

A transmission power calculating section for calculating transmission powers required for communication from the base station to each terminal station for each sector antenna of the base station; And
A transmission power alignment unit for aligning the calculated transmission powers according to sizes of the sector antennas and allocating frequency channels in the order of the aligned transmission powers;
Transmission power control apparatus of a sector antenna system comprising a.
The method of claim 1,
If the difference between each of the larger transmit powers adjacent to each of the aligned transmit powers and the aligned transmit powers exceeds an adjacent channel threshold, the adjacent transmit powers and the ranges do not exceed the allowable frequency channel number. And an adjacent channel transmission power adjustment unit for inserting and adjusting an extra channel between the aligned transmission powers.
The method of claim 2,
And the number of extra channels is calculated by the following equation.
Number of spare channels = [((adjacent transmit power-transmit power)-1) / adjacent channel threshold]
Where [] is a Gaussian function symbol.
The method of claim 2,
The adjacent channel transmission power adjusting unit adjusts each of the aligned transmission powers so that the difference of the transmission powers satisfies the adjacent channel threshold when the difference of the transmission powers exceeds the adjacent channel threshold even after the formation of the redundant channel. Transmission power control apparatus for a sector antenna system, characterized in that.
The method of claim 1,
If the difference between the larger adjacent neighboring transmit power and each aligned transmit power among the aligned transmit powers exceeds the adjacent channel threshold, the difference of the transmit powers is aligned so as to satisfy the adjacent channel threshold. And an adjacent channel transmission power adjusting unit for adjusting each transmission power upward.
The method of claim 5, wherein
And the adjacent channel transmission power adjusting unit performs the upward adjustment from the transmission power adjacent to the adjacent transmission power having the largest value among the aligned transmission powers.
The method of claim 1,
The sector antenna is arranged in four or more even numbers,
If the difference in transmit power between symmetric sector antennas of each sector antenna in the same channel among the allocated channels exceeds the same channel threshold value, the transmit power of the smaller transmit power value of the symmetric sector antennas is satisfied to satisfy the same channel threshold value. And a co-channel transmit power adjusting unit for adjusting upward.
7. The method according to any one of claims 2 to 6,
The sector antenna is arranged in four or more even numbers,
After the adjustment in the adjacent channel transmission power adjusting unit, if the difference in the transmission power between the symmetric sector antennas of each sector antenna in the same channel exceeds the same channel threshold, the transmission of the symmetric sector antenna to satisfy the same channel threshold And a co-channel transmit power adjuster for upwardly adjusting the transmit power of a small value of the power.
The method according to any one of claims 1 to 7,
And the alignment of the transmission power alignment unit is one of ascending, descending, and center alignment.
Calculating transmission powers for communication from the base station to each terminal station for each sector antenna of the base station; And
Arranging the calculated transmission powers according to sizes of the sector antennas and allocating frequency channels in the order of the sorted transmission powers;
Transmission power control method of a sector antenna system comprising a.
11. The method of claim 10,
After the assignment step,
The adjacent transmission power and the adjacent transmission power within a range not exceeding an allowable frequency channel number such that a difference between the larger transmission power adjacent to each of the aligned transmission powers and the aligned transmission power does not exceed an adjacent channel threshold. And inserting or adjusting an extra channel between the aligned transmit powers or adjusting the aligned transmit powers upwardly.
11. The method of claim 10,
The sector antenna is arranged in four or more even numbers,
After the assignment step,
Adjusting the transmit power of the smaller of the transmit powers of the symmetric sector antennas so that the difference in the transmit power between the symmetric sector antennas of each sector antenna in the same channel among the allocated channels does not exceed the same channel threshold; Transmitting power control method of a sector antenna system comprising a.
11. The method of claim 10,
The sector antenna is arranged in four or more even numbers,
After the assignment step,
The adjacent transmission power and the adjacent transmission power within a range not exceeding an allowable frequency channel number such that a difference between the larger transmission power adjacent to each of the aligned transmission powers and the aligned transmission power does not exceed an adjacent channel threshold. Inserting or adjusting an extra channel between each aligned transmit power or upwardly adjusting each aligned transmit power; And
After the adjustment, adjusting the transmit power of the smaller one of the transmit powers of the symmetric sector antennas so that the difference in the transmit power between the symmetric sector antennas of each sector antenna in the same channel does not exceed the same channel threshold value. A transmission power control method of a sector antenna system, characterized in that.

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