CN1242129A - Frequency assigning method in a seven cell frequency plan for a cellular communications system without adjacent frequencies - Google Patents

Abstract

A cell cluster for use with a frequency re-use pattern is disclosed. The cell cluster comprises seven antenna sites arranged in first and second adjacent columns having four sites associated with the first column and three sites associated with the second column. Frequency groups are assigned to each of the antenna sites such that no adjacent channel interference exist between the antenna sites or between any similarly configured cell clusters associated with the cell cluster.

Description

There is not the frequency allocation method in the adjacent frequency planning of cellular communications system seven cell frequently

Background of invention

Technical field

The present invention relates to the channeling structure, particularly a kind of channeling structure, it comprises has eliminated the seven cell group that adjacent channel disturbs basically.

Correlation technique

Frequency reuse mode is based on the structure of sub-district, distributes the channel in the cellular radio system in view of the above.The elementary cell of all frequency reuse modes is sub-districts.Some channels have all been distributed in each sub-district in the frequency reuse mode.One group of cell combination just is called a group together.A group comprises all channels of a certain cellular-specific formula radio system.The group that the group forms is used to that then honeycomb fashion is carried out in a specific region of cellular system and covers.All channels in the single group join together to make the multiplexing possibility that becomes of channel in the whole cellular system.

The purpose of group's formation and group interior Frequency Distribution is to increase multiplex distance and suppress co-channel and the adjacent channel interference.Co-channel interference is included in the interference of using same frequency to cause in two different area groups.Adjacent channel disturb to be to be caused by the interference with adjacent channel in a group or two distinct groups.In order to reduce the interference in the cellular system, just co-channel and interference adjacent channel must be reduced to minimum.Requiring afoul with these is the needs that increase power system capacity.Generally speaking, the sub-district in the mobile radio system in the group is few more, and the capacity of system is just big more, and co-channel multiplex distance is also more little.Certainly, co-channel multiplex distance is more little, and co-channel interference is also just big more.

In the honeycomb fashion industry, frequency reuse mode has been carried out extensive studies.Proposed to reduce to greatest extent the frequency reuse mode that adjacent channel disturbs for area group more than nine sub-districts.Yet existing research claims, when the number of sub-district in the group less than nine the time, the interference of adjacent channel is just inevitable.Existing frequency reuse mode is all used the sub-district less than nine, the problem that they all have adjacent channel to disturb.If system can allow to use the sub-district number less than nine group, it has increased channel capacity, good co-channel interference characteristic is provided and has eliminated the adjacent channel interference basically, so, it will make user and cellular phone service supplier greatly benefited.

Summary of the invention

The present invention utilizes a modified model area group that is used for frequency reuse mode, has solved an aforementioned difficult problem and other difficult problem.In first embodiment, area group comprises seven sub-districts, lines up first and second row in level, vertical or diagonal.First row comprise four sub-districts and secondary series comprises three sub-districts.In seven sub-districts each has all been distributed seven different group of frequencies.Each group of frequencies all includes only non-adjacent channel, and the distribution of seven group of frequencies makes all do not have adjacent channel between any two in seven sub-districts, and any similar area group that utilizes this seven cell group to become does not have adjacent channel yet.

Above-mentioned area group uses a kind of omnidirectional structure, and wherein seven omnidirectional antennas place the center of each sub-district, seven sub-districts, perhaps uses the fan-beam antenna structure of a kind of center excitation, and wherein each group in seven group of frequencies also comprises three groupings.Each grouping in the group of frequencies is all without any adjacent channel.

In second embodiment, seven antenna websites are lined up first and second adjacent column or adjacent row, and wherein four antenna websites are drawn together in first row or first package, and secondary series comprises three antenna websites.Each antenna website is bordered on three sub-districts, and each sub-district is all adopted three directional antennas and formed one 21 area group.Be placed with antenna at each antenna website, transmit to three sub-districts that border on this point with three sectors.Seven group of frequencies that comprise three groupings that do not have adjacent channel are assigned to each antenna website, each sub-district receives a grouping, make that any two all do not have adjacent channel in 21 sub-districts that border on seven antenna websites, any analog structure of area group does not have adjacent channel yet.

The accompanying drawing summary

In order more fully to understand the present invention, will be with reference to following detailed introduction and accompanying drawing, wherein:

Fig. 1 is seven cell group's a block diagram, and it uses the omnidirectional antenna structure, does not have adjacent channel to disturb in a group;

Fig. 2 illustrates the frequency re-use planning of the area group of N=7, and it uses the omnidirectional antenna structure, does not all have adjacent channel to disturb between any two groups;

Fig. 3 illustrates the fan-beam antenna structure of center excitation in the seven cell group, and wherein each group of frequencies further comprises three independent groupings, with there not being adjacent channel to disturb in a group;

Fig. 4 illustrates a frequency reuse mode of the area group of N=7, and the fan-beam antenna structure of its use center excitation does not all have adjacent channel to disturb between any two groups;

Fig. 5 illustrates the cloverleaf structure of using group structure; With

Fig. 6 illustrates the frequency reuse mode of cloverleaf structure.

Detailed Description Of The Invention

With reference now to accompanying drawing,, Fig. 1 particularly, it is the fundamental group of the omni-directional mode of N=7, N equals a channeling number (sub-district number) in the group.This pattern is a rectangle area group 10, and it has the sub-district 12 of four vertical arrangements and the sub-district 14 of three vertical arrangements that are close to.This pattern that at once will discuss in more detail and frequency allocation plan correspondingly provide all fundamental characteristics of common multiplexer mode, but for example repeatability fissility and applicability.In addition, two row 12,14 of four sub-districts and three sub-districts can also be arranged by horizontal direction or diagonal, and are not only vertical direction.

The N=7 frequency planning of the suggestion of omnidirectional antenna website shown in Figure 1, its basis are that all channels are divided into seven or a multiple group of frequencies of seven, a nearly t/7 channel in each group, and wherein t is total number of channel in the frequency band of authorities' distribution.The channel allocation of an omnidirectional antenna system of table 1 explanation.

Table 1 channel-group

a b c d e f g

1 2 3 4 5 6 7

Channel 89 10 11 12 13 14

15 16 17 18 19 20 21

As can be seen from Table 1, each channel is all distributed to each channel-group in order.Channel-group has been eliminated in the group and the adjacent channel between the adjacent group with this arrangement of sub-district.After being assigned to first group, these same frequencys can also be multiplexing by other group according to same distribution structure, covers so that honeycomb fashion to be provided a specific region.

Basic seven cell is mined massively with a kind of strange, even allocative decision, and wherein strange, even two the vector A of channel formation and the B of fundamental group are as follows: $A=\left[\begin{array}{c}a\\ e\\ b\\ f\end{array}\right]B=\left[\begin{array}{c}c\\ g\\ d\end{array}\right]$ $A=\left[\begin{array}{c}f\\ b\\ e\\ a\end{array}\right]B=\left[\begin{array}{c}d\\ g\\ c\end{array}\right]$

Vector A comprises four channel-group, and vector B comprises three channel-group.Vector A is assigned to four sub-districts row, and vector B is assigned to three sub-districts row.As can be seen, the adjacent channel group is separated by at least one other channel-group, and making can not have adjacent channel on the vertical direction.Therefore, a-b group, e-f group and c-d group all are separated from each other by other group.The adjacent channel group is also separated by at least one other channel-group in the horizontal direction, to occur adjacent possibility frequently on the elimination of level direction.Like this, b-c group, d-e group, f-g group and a-g group are all by at least one group of frequencies separately.

As Fig. 2, the seven cell group is combined in together in a frequency reuse mode.Utilize each group, the channel frequency that distributes in the cellular system is re-used.Because the fundamental group shape of N=7 and the relation of omnidirectional antenna can only be in vertical direction and horizontal direction expansion fundamental groups.Obtain a group of frequencies repetitive sequence of Fig. 2 structure like this, it has suppressed co-channel interference and has eliminated the adjacent channel interference, sees Table 2.

Table 2

a c a c a c

e g e g e g

b d b d b d

f a f a f a

c e c e c e

g b g b g b

d f d f d f

a c a c a c

e g e g e g

b d b d b d

f a f a f a

c e c e c e

g b g b g b

d f d f d f

From Fig. 2 as seen, always with the Serving cell sub-district (centre-to-centre spacing is 3R) that is separated by, wherein R is the radius of society of each sub-district to the same channel on horizontal direction both sides.The frequency shift (FS) of being separated by in the horizontal direction of the same channel of vertical direction six sub-districts (centre-to-centre spacing is 14R) that always are separated by, the same channel of diagonal, (centre-to-centre spacing is in three frequency shift (FS)s and be separated by in vertical direction

).Same channel sub-district on the diagonal with respect to Serving cell be about and laterally zygomorphic.Co-channel jamming performance like this is equal to or slightly is better than common seven cell group structure.

The omnidirectional antenna pattern most important characteristic of this N=7 is not have adjacent channel to disturb in the group, and is also like this between two distinct groups.So,, do not had adjacent channel to disturb to reduce widely interference total in the mobile communication system though this characteristic frequency multiplexer mode provides with the same message capacity of common N=7 system.This is because in mobile communication system, disturbs to have comprised that noise adds adjacent channel and disturbs, and adds co-channel interference again.Since noise is limited in the mobile communication system, this means that therefore not being to reduce the adjacent channel interference will reduce co-channel interference exactly.Since the co-channel interference of this structure about equally or omit, so the elimination that adjacent channel disturbs has improved systematic function.

Frequency reuse mode of the present invention can also be used for the fan-beam antenna cell structure.This structure is used for example 21 group of frequencies in three sector cells of every group of seven website multiplexer modes that have an approximate t/21 channel, wherein t equals the interior channel number of frequency band.Table 3 explanation of this channel allocation mode.

Table 3 channel-group

a1?b1?c1?d1?e1?f1?g1 a2?b2?c2?d2?e2?f2?g2 a3?b3?c3?d3?e3?f3?g3

123456789 10 11 12 13 14 15 16 17 18 19 20 21 channel

22?23?24?25?26?27?28 29?30?31?32?33?34?35 36?37?38?39?40?41?42

As can be seen, each group of frequencies in omnidirectional's structure (a, b, c, d, e, f, g) be divided into three different groupings (a1, a2, a3, b1, b2, b3, c1, c2, c3), and the frequency grouping has all been distributed in each sector.The direct expansion that the sector cell of center excitation and frequency planning are the omnidirectional antenna structure.The frequency packet mode is the same with the omnidirectional antenna pattern, and each group of frequencies of everywhere is divided into three groupings in fan-shaped planning.For example, the group of frequencies a in omnidirectional's planning is divided into group of frequencies a1, a2 and a3 now; Group of frequencies b is divided into b1, b2 and b3; Or the like.Group of frequencies a1, a2 and a3 are given three fan sections of a fanned partition website subsequently.Two kinds of different sector cell patterns are arranged, i.e. center excitation with the cloverleaf cell pattern.

Fig. 3 represents a group of three sector directional antenna patterns of center excitation.Each website has an individual antenna website 18 and three antenna direction azimuths to differ 120 ° sector 20.What should be understood that Fig. 3 introduces is three fan section structures, and other many sector strucres also are fine.Each sector 20 all uses a rhombus to be similar to.The transmitting antenna and two diversity reception antennas that have identical sensing angle accordingly as 60 °, 90 ° or 120 ° can be used in each sector 20.Three sector patterns of center excitation will represent that the hexagon of website is divided into three rhombuses, and will have a frequency component of three groupings to give each website.Three groupings of channel frequency group are assigned to each sector 20 of website, as shown in Figure 3.

With reference now to Fig. 4,, the same with the omnidirectional antenna structure, group's shape of center, three sectors incentive structure also only allows in vertical direction and horizontal direction expansion.This structure has the co-channel Serving cell interval of 3R distance (center-center) two horizontal directions.The co-channel of vertical direction is separated by The co-channel 3R/2 of being separated by in the horizontal direction on the diagonal is separated by in vertical direction

With the Serving cell is reference, the same channel on the diagonal all be about, laterally zygomorphic.With the another sample of omnidirectional antenna planning situation, therefore neighbor cell, adjacent sectors or adjacent group, do not have adjacent channel to disturb without any adjacent channel.

With reference now to Fig. 5,, the group of the cloverleaf structure of three sector directional antenna patterns of the fanned partition that drawn.At each antenna website, website comprises three sub-districts how much, and wherein the antenna directional angle of each sub-district all is separated by 120 °, and these sub-districts all are the cloverleaf structures.It is a hexagon that each sub-district all is similar to, and on each antenna directional angle, all uses transmitting antenna and two corresponding diversity reception antennas of for example 60 °, 90 ° or 120 °.

The cloverleaf structure comprises three sub-districts, is one pair of antenna at the center of first Mu impeller structure.Each antenna website all is assigned a group of frequencies that comprises three groupings, and mode is the same with center previously discussed incentive structure.Therefore, each website all is assigned frequency a1, a2, a3; B1, b2, b3 etc. see figure.The channel that seven antenna websites that the cloverleaf pattern is used distribute has identical relation with the channel of the sector structure of omnidirectional or center excitation.The antenna website is positioned at the intersection point of three neighbor cells, rather than is positioned at the center of each sub-district.

Fig. 6 for example understands group's multiplexer mode of cloverleaf structure.Because the fundamental group shape of directed 7/21 planning of the cloverleaf of three fan-shaped divisions can only be expanded fundamental group with vertical direction in the horizontal direction.From Fig. 6 as seen, the same channel of horizontal direction always is separated by

(center-center), and the 21R of always being separated by on the vertical direction.The same channel of diagonal all is separated by up and down Always have six co-channel interference sources at first co-channel row.Neighbor cell or sector be again without any adjacent channel in the group, and also do not have the adjacent channel interference between group and the group.

Because the directivity of antenna, the same channel on vertical direction and the diagonal is bigger to the influence of co-channel interference, and the same channel on the horizontal direction is less to the interference effect of Serving cell.But the same channel on the vertical direction is at a distance of farther, thereby because the directivity of antenna has been offset the influence that same channel is disturbed.

The preferred embodiments of the invention and equipment in above-mentioned detailed description, have been introduced though utilize accompanying drawing, be understood that the embodiment that the present invention is not limited to announce, but comprise many adjustment, modification and replacement, but do not depart from spirit of the present invention, illustrate as claim subsequently.

Claims (23)

1. area group that is used for frequency reuse mode, wherein area group comprises:

Line up seven sub-districts of first and second adjacent column, wherein first row comprise four sub-districts, and secondary series comprises three sub-districts; With

Seven sub-districts of seven frequency component dispensings make that as long as each group of frequencies all is assigned to a sub-district any minizone does not just all have adjacent channel.

2. the area group of claim 1, wherein seven sub-districts do not produce adjacent channel with the seven cell group of other similar arrangement between any adjacent group's sub-district.

3. the area group of claim 2, wherein the co-channel (adjective) horizontal range is 3R.

4. the vertical range between the area group of claim 2, wherein co-channel and sub-district is 14R.

5. the area group of claim 2, wherein co-channel between the distance of diagonal be sub-district on the horizontal direction, three sub-districts on the vertical direction.

6. the area group of claim 1 also comprises with each relevant omnidirectional antenna website in the seven cell.

7. the area group of claim 1 also comprises and is arranged in each the fan-beam antenna website of central point of seven cell.

8. the area group of claim 7, the horizontal range between wherein co-channel is 3R.

9. the vertical range between the area group of claim 7, wherein co-channel and sub-district is

10. the area group of claim 7, wherein co-channel between the distance of diagonal be horizontal direction 3R/2, vertical direction

.

11. the area group of claim 1, wherein seven group of frequencies are denoted as a, b, c, d, e, f, g, all channels all in order from group of frequencies a to group of frequencies g duplicate allocation.

12. the area group of claim 11, wherein two side frequency groups are not distributed in the sub-district that physics is adjacent in the area group.

13. a frequency re-use planning comprises:

Be less than some antenna websites of nine, combine with a kind of mode of repetition;

Distribute to some group of frequencies of antenna, after all group of frequencies have all been distributed, do not have two sub-districts that adjacent channel is arranged.

14. the frequency re-use planning of claim 13, wherein the number of antenna website is 7.

15. the frequency re-use planning of claim 14, wherein each antenna website comprises the sub-district of a fanned partition, and it is receiving and transmitting signal in the sub-district of three cloverleaf patterns.

16. the frequency re-use planning of claim 14, wherein the horizontal range between the adjacent channel is

17. the area group of claim 14, wherein the vertical range of adjacent channel is 21R.

18. the area group of claim 14, wherein the diagonal distance of adjacent channel is

19. an area group that is used for frequency re-use planning comprises:

Vertical arrangement becomes seven sub-districts of first and second row, wherein first shows four sub-districts, and second shows three sub-districts;

Seven group of frequencies, there is not adjacent channel in each group of frequencies, wherein each in seven group of frequencies is assigned in seven sub-districts one, and making arbitrary cells in seven sub-districts follow between the arbitrary cells group with analog structure who is associated with this area group does not all have adjacent channel.

20. the area group of claim 19 also comprises with each omnidirectional antenna website that is associated in seven sub-districts.

21. also comprising, the area group of claim 19 is arranged in each the fan-beam antenna website at center of seven sub-districts.

22. the area group of claim 19, wherein seven group of frequencies are denoted as a, b, c, d, e, f, g, all channels all in order from group of frequencies a to group of frequencies g duplicate allocation.

23. the area group of claim 19, wherein group of frequencies comprises that three distribution have or not the grouping of adjacent channel.

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