RU2312468C2 - Circuit of cells for connecting one client to several and a transition - Google Patents

Abstract

FIELD: engineering of cell circuits and alteration of cell circuits in systems for connecting one client to several.

SUBSTANCE: in accordance to the invention, a system of cell circuits is claimed, containing cells, having four 90° sectors, wherein for individual sector at least one of four orthogonal channels is distributed, for example, channels, differing in two frequencies and two polarizations. Also a method is claimed, providing capacity for gradual transition, sector after sector, to circuit of cells with 45° sectors. Cell circuit offers efficient improvement to carrier/interference ratio.

EFFECT: improved system of cell circuits, using sector antennas, relatively to carrier/interference value and transition perspectives.

11 cl, 16 dwg

Description

FIELD OF THE INVENTION

The present invention relates to cell circuits and changes in cell circuits in the connection systems of one subscriber with several (SOAN). More specifically, the present invention relates to cell schemes in which at least four sectors are initially available for the base station, and in which, for example, four channels are available.

State of the art

In cellular communication systems, dividing the territory into cells is necessary because the frequency spectrum is limited, and since it is usually necessary to use this frequency spectrum repeatedly. In fixed wireless cellular systems, the carrier to interference ratio (N / A) is an important system parameter that imposes restrictions on other system design parameters that can be used by a particular modulation circuit to transmit signals over the air.

For the aforementioned type of systems, improvements in N / A can be obtained by spatial filtering, for example, when using stationary multipath antennas in cellular communication systems.

EP1176839 shows a single-to-multiple-subscriber connection system having sectorized antennas dividing cells into 90 ° sectors. By “tilting the core of the network”, please compare FIGS. 12 and 13 of EP1176839, copolar interference can be reduced to a minimum.

WO 9721309 shows a cell layout using 180 ° sectors.

Document WO 95/35601 A1 shows a cell layout using, for example, two frequencies and two orthogonal polarizations. Each base station communicates with two out of four sectors.

US2001055970 A1 shows a cell circuit system for a time division duplex (TDD) system in which each base station uses four sectors via directional antennas. Sectors use the same frequency and polarization. Existing base stations can use one type of polarization, while additional base stations use a different polarization. Alternatively, all sectors in each base station use the same frequency, but two types of polarization.

US Pat. No. 5,838,670 shows a microwave radio communication system of a single subscriber with several, in which FIGS. 2A and 2c show cell diagrams consisting of two unique cell configurations that are periodically distributed across a geographic area. The cell pattern has a reusable distance of two. The cell configuration of FIG. 2A allows 90 ° sectors to be used, whereby the same channel is used in opposite directions. The cell layout of FIG. 2A is similar to that of FIG. 5 of the present invention, and FIG. 2B is similar to FIG. 1 of the present invention, although the sectors of both circuits are rotated 45 °. In the cell configuration structure of FIG. 2C, 45 ° sectors are used, and it is reproduced as FIG. 2 of this document.

Figure 1 shows a well-known cell scheme according to a time division multiple access (TDMA) system for connecting one subscriber with several (SOAN) with sector antennas, indicated by Ericsson MINI-LINK BAS, "MINI-LINK BAS Planning and Engineering Manual "(MINI-LINK BAS Planning and Technical Manual), AE / LZT 111 0541 RIB, Ericsson Microwave Systems AB, 2001.

As a rule, the frequency range and the number of channels according to official regulations are fixed in relation to the area where the system is allowed to work. So, when more users require more bandwidth, one way to expand system bandwidth is to further partition the cells into sectors.

This operation requires a new cell layout, which requires new equipment and antennas to be installed at the base stations, and modification of existing antennas, for example, from a 90 ° sector beam pattern to a 45 ° sector beam pattern. In systems where different polarizations are used, the antennas can be tuned to perform a change, for example, from vertical polarization to horizontal polarization. Therefore, the transition properties of the aforementioned type of system should be considered.

SUMMARY OF THE INVENTION

The first objective of the present invention is to formulate an improved system of cell circuits using sector antennas in relation to the magnitude of N / A and the prospects for the transition.

This problem is solved by means of the object of the invention defined in claim 1.

An additional objective is the conditions for further improvement of N / A.

This problem is solved by means of the object of claim 2 of the claims.

An additional task is to formulate a method for performing channel changes in a system of cell circuits that includes at least one sector to be partitioned.

This problem is solved by the object of the invention defined in accordance with paragraph 3 of the claims.

An additional task is to formulate a method for performing channel changes in a system of cell circuits that includes at least one sector to be partitioned.

This problem is solved by means of the object of the invention defined in accordance with paragraph 3 of the claims.

An additional task is to formulate a method for performing channel changes, which includes at least two sectors to be divided.

This problem is solved by means of the object of the invention defined in accordance with paragraph 4 of the claims.

Further advantages will be apparent from the following detailed description of the invention.

Brief Description of the Drawings

FIG. 1 depicts an exemplary sample (3 x 3 network core) from a 90 ° cell layout of sectors of the well-known SOAN system,

FIG. 2 depicts an exemplary sample of a 45 ° sector cell layout having the same structure as the well-known SOAN system,

FIG. 3 depicts a cell diagram of a 2 x 2 network core containing four cells with 90 ° sectors, in which the symbols X, * and # illustrate the limiting optimization conditions 1, 2 and 3, respectively, with respect to the hatched sector,

FIG. 4 depicts a cell diagram of a 2 x 2 network core containing four cells with 45 ° sectors, in which the symbols X, * and # illustrate the limiting optimization conditions 1, 2 and 3, respectively, relative to the shaded sector,

FIG. 5 depicts an exemplary sample of a 90 ° sector cell layout according to a first embodiment of the invention,

FIG. 6 discloses the maximum number of simultaneous main sources of interference of a combined uplink channel (from a mobile subscriber to a base station) in a 90 ° cell layout of FIG. 5, limited by the length of the core of the network 3 x 3, which is three, one and zero, respectively, including sectors with a maximum of three and zero simultaneous sources of interference combined channel, which are the worst and best sectors from the perspective of N / A uplink, whereby sectors without any digit have a maximum of one simultaneous common channel interference source,

FIG. 7 discloses the maximum number of simultaneous main sources of interference of an uplink shared channel in a 45 ° cell layout of FIG. 2, which is two, one and zero, respectively, whereby sectors with a maximum of two and zero simultaneous sources of interference of the combined channel are identified, which are the worst and best sectors from the perspective of N / A uplink, and whereby sectors without any digits have a maximum of one simultaneous interference source of a combined channel,

FIG. 8 discloses a DF (distribution function) of uplink N / A per sector for the well-known 90 ° cell scheme shown in FIG. 1, for the length of the 3 × 3 network core cell scheme, including the maximum number of common channel interference sources per sector (3 ', 1' or 0 ', respectively),

FIG. 9 discloses uplink N / A RFs per sector for a 90 ° cell layout shown in FIG. 5, for the length of the cell scheme of the core cells of the network 3 x 3, including the maximum number of sources of interference combined channel per sector (3 ', 1' or 0 ', respectively),

FIG. 10 depicts a transition strategy to be used when moving sector by sector from the cell layout of FIG. 2 to FIG. 5,

FIG. 11 depicts a first and second cell partition in a method for performing cell change according to the invention,

FIG. 12 depicts a first near optimal cell layout that is suitable for transitioning from the cell layout of FIG. 5,

FIG. 13 depicts a second, near optimal, cell layout that is suitable for transitioning from the cell layout of FIG. 5,

FIG. 14 depicts a third, near optimal, cell layout that is suitable for transitioning from the cell layout of FIG. one,

FIG. 15 depicts a fourth near-optimal cell layout that is suitable for transitioning from the cell layout of FIG. 1 and

FIG. 16 depicts a fifth near optimal cell layout that is suitable for transitioning from the cell layout of FIG. one.

Detailed Description of Preferred Options

the implementation of the invention

In the future, the terminology of cells and sectors will be used. A “cell” refers directly to the zone irradiated by the core of the network, while “sectors” refers to the zones dividing a given cell. The cell may be populated by a number of terminals, which preferably have a fixed location. It should be clear that this sector can be determined by the direction in which it is located relative to the core of the network to which it belongs. Therefore, in the future, the concept of "corresponding to the same" sector refers more to those sectors that are oriented in the same given direction relative to these corresponding cells in which sectors can be located than to one specific sector in a given cell.

Let's look at the unit cell of the 2 x 2 network core shown in FIG. 3 for 90 ° cells and in FIG. 4 for 45 ° cells. If four unique channels are available and symmetry is ignored, 4 ¹⁶ and 4 ³² cell patterns are possible for 90 ° and 45 ° cell designs, respectively.

However, a large number of these possible cell designs are not suitable, since some co-channel assignments are undesirable. Assume that this channel has been allocated for a given sample sector (shaded) in FIG. 3 and 4, then the following limiting conditions may be imposed:

1) The assignment of the combined channel in adjacent sectors in the same network core (X) is not allowed,

2) The assignment of a combined channel in the same sectors in other network cores (*) is not allowed,

3) Assignment of a combined channel in sectors in two adjacent network cores in the direction of sector boundaries (#) is not allowed.

When considering the 45 ° sectors of FIG. 4, the following additional limiting conditions may be selected:

4) A specific channel is allocated for an even number of sectors per cell.

If a smooth transition from 90 ° to 45 ° sectors is desired, a fifth limiting condition may apply to 45 ° cell designs. In this example, the channel is characterized by one frequency and one polarization.

5) In two adjacent 45 ° sectors, covering the previous 90 ° sector, the polarization should be the same as in the 90 ° sector.

The above limiting conditions have been set forth as optimization criteria for various aspects of the present invention.

FIG. 5 depicts an exemplary sample of a 90 ° sector cell layout according to a first embodiment of the invention. This system of cell schemes has very advantageous N / A properties.

It should be understood that the 90 ° cell layout of FIG. 5 also applies to smaller and larger networks, since a network with a 3 x 3 network core is only an exemplary configuration of a periodic structure.

The network cores in the above cell scheme describe a grid of cells having a substantially square shape, which, of course, may, under actual implementation, be subject to some distortion due to the geography encountered.

The aforementioned cell layout system comprises cells having four 90 ° sectors. For each individual sector, at least one of four orthogonal channels may be allocated. For example, two frequencies and two directions of polarization are used.

The system has a first type of 6 cells having a first channel a distributed for sectors of the opposite direction, and a second channel B distributed for sectors of the opposite directions, and a second type of 7 cells having the same channel distribution as the first type of cells, but rotated 90 ° relative to the first type of 6 cells. The first and second types of cells are arranged in an alternating or alternating manner along diagonal 5.

The diagonal can be seen as a 45 ° line crossing the core of the network in a configuration of cells having a substantially square shape.

In addition, the cell circuit system comprises a third type of 8 cells having a third channel b allocated for sectors of the opposite direction, and a fourth channel A distributed for sectors of the opposite direction, and a fourth type 9 of cells having the same channel distribution as the third type 8 cells, but located with a rotation of 90 ° relative to the third type of cells. Also, the third and fourth type of cells are arranged alternately diagonally.

It should be noted that the first and third types are placed in an alternating manner along a line located at an angle of 45 ° relative to diagonal 5. It should also be noted that the second and fourth types are placed in an alternating manner along another line located at an angle of 45 ° relative to diagonal 5, although it is clear from the fact that both the first, second, and also third and fourth types of cells are placed in an alternating manner along the diagonals.

FIG. 6 discloses the maximum number of simultaneous main uplink shared channel interference sources per sector in the 90 ° cell layout of FIG. 5, of a limited 3 × 3 network core length of three, one and zero, respectively, whereby sectors without any digits have a maximum of one simultaneous common channel interference source. It seems that, in accordance with this, sectors with a maximum of three simultaneous sources of interference of the combined channel are the worst. Sectors with one interference source are intermediate, and sectors with zero interference sources are the best from the perspective of N / A uplink.

FIG. 7 discloses the maximum number of simultaneous main sources of interference of an uplink shared channel per sector in a 45 ° cell layout of FIG. 2, comprising two, one and zero, respectively, and whereby sectors without any digit have a maximum of one simultaneous common channel interference source.

It should be noted that the maximum number of main sources of interference of a combined channel is reduced from three in a 90 ° cell scheme to two in a 45 ° cell scheme, as shown in FIG. 6 and 7.

FIG. 8 discloses uplink N / A RFFs per sector for a known 90 ° cell layout shown in FIG. 1 for a 3 x 3 length cell network core scheme, including the maximum number of common channel interference sources per sector. The relation is indicated for sectors with three 3 ', one 1' or zero 0 'interference sources, respectively.

FIG. 9 discloses uplink N / A RFFs per sector for an optimal 90 ° cell layout shown in FIG. 5, for a length of 3 x 3 cell network core schemes, including the maximum number of common channel interference sources per sector. The ratio is indicated for sectors with three 3 ', one 1' or zero 0 'main sources of interference, respectively.

FIG. 8 and 9 were obtained using a modeling tool assuming that all base stations and terminal antennas have this imperfect standard characteristic of the ETSI (European Telecommunications Standards Institute) class antenna, including a specific side lobe pattern. A particular implementation of the cell pattern will, to varying degrees, affect the interference resulting from the non-ideal side lobe pattern.

When comparing FIG. 9 from FIG. Figure 8 shows that a significant gain in N / A was performed for the 90 ° cell scheme according to the invention for sectors having zero main sources of interference. It is shown that N / A improvements of 5-7 dB were made for sectors that are exposed to zero sources of interference on a shared channel. As it turned out, sectors with one or three main sources of interference are essentially unaffected. It should be noted that the improvements strongly depend on the manifestation of the pattern of the side lobes.

The cell layout of FIG. 5 provides improved isolation between channels for distributing only frequency channels and even better results for distributing combined frequency and polarization channels.

An improved N / A ratio may lay the foundation for the introduction of higher order modulation schemes for higher data rates.

Furthermore, according to the invention, the cell layout of FIG. 5 is used as an excellent starting point for transitioning to the well-known cell layout of FIG. 2.

According to a second aspect of the invention, a method for transitioning from the aforementioned cell layout of FIG. 5 to the well-known cell scheme of FIG. 2.

Regarding the transition from 90 ° to 45 ° sectors, the best result was obtained from the perspective of N / A efficiency if the entire 90 ° cell layout of FIG. 5 directly changed to a 45 ° cell layout of FIG. 2.

There may be various reasons as to why the transition should be performed gradually, that is, why modifications should be made based on the transition of the network core behind the network core. In a typical transition scenario, there is a need for more bandwidth among some users in local zones in the cell layout. Therefore, in order to meet the needs of these users, it is beneficial to implement as small a change as possible. The gradual introduction of sectorization, which determines the priorities of these users or cells that have specific needs, usually constitutes a more favorable economic solution.

According to the invention, a gradual implementation of a network change in certain network cores can be performed while the remaining network is operating, thus undergoing a minimum interruption during network change.

Transition to the cell layout of FIG. 2 includes dividing 90 ° sectors into 45 ° sectors. By way of example, an explanation will be given of the division of sectors and the change of channels in this first sector, and after that in the second sector. These changed sectors will correspond to a sample from the cell layout of FIG. 2.

With respect to FIG. 11, only those 45 ° sectors directed along or parallel (or sectors having at least one direction directed substantially along or parallel) of the first line 20 to the 90 ° boundary of the sector, where the first line is located at an angle of 45 ° relative to diagonal 5 , are “considered” to change channels, while sectors directed along a line perpendicular to the first line should remain unchanged. It should be understood that the orientation of line 20 is arbitrary as long as it remains determined during the change procedure. Those 45 ° sectors that diverge along the first line 20 are candidates for changing channels.

When identifying any first 45 ° sector 13 considered to change channels, a second 45 ° sector 14 is identified at the corresponding sector position in the cell in the horse-riding area 11 found in the direction of the identified 45 ° sector. Subsequently, the channel of the identified first 45 ° sector 13 is changed so as to accept the channel b used in the old cell circuit of FIG. 5 at a location corresponding to the second 45 ° sector 14. As indicated in FIG. 11, sector 13 of cell 10 varies from a to b.

It should be understood that the term “cell in the area of the knight’s move” is used by analogy with the region of the move of the knight in the chess game, where the cells correspond to the squares of the chessboard. In the present example, the cells 11 and 12 are in the region of the knight with respect to the cell 10.

You can select any further unchanged sector, considered for partitioning the sector and sequentially changing channels using the same change rules as described above.

When selecting a sector directed “out of bounds” —for example, sector 14 in cell 11 in FIG. 11 does not indicate any other sector — a further change may include a change in which the channel of the identified second 45 ° sector 14 changes so as to accept the channel used in the old cell layout of FIG. 5 at a location corresponding to the identified first 45 ° sector 13, therefore, sector 14 of cell 11 changes from b to a.

Sectors 15 and 16 remain unchanged since they are not oriented so as to radiate along line 20.

It should be noted that the channels that are suitable for selection are channels that were originally in the cell layout.

It should be noted that it is possible to return from the 45 ° cell layout of FIG. 2 back to the 90 ° cell layout of FIG. 5.

According to a preferred transition pattern in accordance with the invention, the channels in the cell pattern of FIG. 5 are distributed as follows: channels a and b denote the first and second frequencies of the first polarization, while channels A and B denote the same first and second frequencies, but of a second polarization, orthogonal to the first polarization.

It should be noted that when switching from the cell layout of FIG. 5 to the cell diagram of FIG. 2 individual zones corresponding to 90 ° sectors retain their individual polarization when the sector is divided. For example, a sector using channel B in cell 7 of FIG. 5 are divided into sectors using channels A and B, and a sector using channel a is divided into b and a.

A change in frequency can generally be done more easily than a change in polarity. For example, end devices can be adapted to a new cell layout through software updates. This is a prerequisite for the fifth limiting condition mentioned above.

According to a further embodiment of the invention, careful consideration of the entire 90 ° cell scheme improves the efficiency of N / A with respect to networks ≥ 3 x 3 network cores. In FIG. 10 illustrates considerations for transitioning (or splitting) a 90 ° cell layout of FIG. 5 to 45 ° cell layout of FIG. 2.

If any 90 ° sector in the middle row of cells should be divided into two 45 ° sectors, then no other 90 ° sector is involved. The same holds true for the outermost corner sectors of the corner cells and their respective nearest neighbors. All these 90 ° sectors are marked with * in FIG. 10.

If any of the eight 90 ° sectors marked with the symbol ▽ is to be divided into two 45 ° sectors, then the sector in the area of the horse · marked with an arrow should preferably be divided into two 45 ° sectors. In the present example, all eight sectors marked with the symbol ▽, and eight corresponding sectors marked with the symbol ·, should preferably be changed at the same time. Otherwise, the sectors marked with the symbol · can act as the leading node as the main potential source of interference of the combined channel. It should be noted that the reversal is not necessary: if the sectors marked with the symbol · are to be split, it is also not necessary to split the sectors marked with ▽.

When taking the above precautions into account, a sequential transition is considered possible without introducing any adverse conditions N / A in other cells, except those that directly affect during the operation of the gradual change of channels. The individual channel assignment of the new 45 ° sectors should be identical to that shown in FIG. 2.

For networks of 1 x 1 and 2 x 2 cells, the optimal 90 ° cell scheme can be transferred to the optimal 45 ° cell scheme based on sector-by-sector transfer, without any adverse conditions.

The cell layout presented after breaking all the cells can be defined as follows:

The cell circuit system comprises cells having eight 45 ° sectors for which at least one of four orthogonal channels, such as two frequencies and two polarizations, is allocated for an individual sector, the system having a first type of cells having a first, second, third and fourth channel distributed for sectors of the opposite direction, and the second type of cells having the same channel distribution as the first type of cells, but located with a rotation of 90 ° relative to the first type of cells. The first and second types of cells are placed alternately along a vertical or horizontal line intersecting the core of the network. The cell circuit system furthermore comprises a third type of cells having first, second, third and fourth channels distributed for sectors of the opposite direction, in which the first and second channel are exchanged around the first diagonal with respect to the first and second channels of the first type of cells. The third and fourth channels are exchanged around the second diagonal relative to the first and second channels of the second type of cells. In addition, a fourth type of cells is provided having the same channel distribution as the third type of cells, but located rotated 90 ° with respect to the first type of cells. The third and fourth type of cells are arranged alternately along a vertical or horizontal line intersecting the core of the network, in which the first and third type of cells are not located, so that the sectors of the same channel are located side by side.

According to further aspects of the invention, cell patterns other than those shown in FIG. 2, starting from FIG. 5.

FIG. 12 depicts a first near optimal cell layout that is suitable for transitioning from the cell layout of FIG. 5.

FIG. 13 depicts a second, near optimal, cell layout that is suitable for transitioning from the cell layout of FIG. 5.

FIG. 14 depicts a third, near optimal, cell layout that is suitable for transitioning from the cell layout of FIG. one.

FIG. 15 depicts a fourth near-optimal cell layout that is suitable for transitioning from the cell layout of FIG. one.

FIG. 16 depicts a fifth near optimal cell layout that is suitable for transitioning from the cell layout of FIG. one.

In conclusion, a system of cell circuits with advantageous properties of the carrier / interference ratio, which can be transferred in ascending order to the second system of cell circuits of higher throughput, is proposed. In addition, various close to optimal systems of cell schemes suitable for the transition have been proposed.

Claims (11)

1. The method of performing the transition from the first cell scheme to the second cell scheme, moreover, the first cell scheme contains cells having four 90 ° sectors, for each of which one of the four orthogonal channels is distributed (a, b; A, B), the first cell scheme includes four specific cell types (6, 7, 8, 9), which are periodically repeated in the first cell scheme, each cell type having a specific channel distribution (a, b; A, B) to a particular sector, wherein a particular channel is allocated for an even number of sectors per cell, the same channel (a, b; A, B) is not allocated for the corresponding sectors (*) - i.e. for sectors with this orientation, all four cell types, the same channel (a, b; A, B) is not allocated for adjacent sectors (X) of any type of cells, the same channel (a, b; A, B) is not allocated for a particular sector of any given type of cells and adjacent sector (#) of any other type of cells for the corresponding sector of a particular sector, found in the directions of the boundaries of a particular sector, namely this pair of corresponding 90 ° sectors of the first and third (6, 8) cell types, respectively, or the second and fourth (7, 9) cell types, respectively, into two pairs (13, 14; 15: 16) of the corresponding 45 ° partition sectors, and re-distribute channels through permutation fishing for one (13, 14) of two respective pairs of partition sectors, while maintaining the distribution channels for the other (15, 16) of said two pairs of partition sectors according to the first scheme of cells the first and third (6, 7) cell types are selected in such a way that any splitting and re-distribution can be performed so that after re-distribution, adjacent sectors of this cell have different channels. 2. The method according to claim 1, in which at least four orthogonal channels are distinguished by two frequencies (a, A; b, B) and two polarizations (a, b; A, B). 3. The method according to claim 2, in which the polarization of any sector of the partition remains unchanged with respect to the previous 90 ° sector during the transition from the first to the second cell scheme. 4. The method according to any one of claims 1 to 3, in which for those sectors of the partition, which are affected by the transition to the second cell scheme, only a frequency change is necessary. 5. The method according to claim 1, in which the first cell scheme has a length of 3 * 3 cells, and the transition initially involves the partition of the cells of the middle row and the angular sectors of the corner cells (*). 6. The method according to claim 1, in which only 45 ° sectors directed along the first line (20) parallel to the 90 ° sector boundary are considered to change channels, while sectors directed along a line perpendicular to the first line are left unchanged . 7. The method according to claim 1, in which for a pair (13, 14) of respective partition sectors for which the step of partitioning and reassigning the channels is performed, one partition sector (14) is found in the beam coverage area defined by the boundaries of another sector (13) partitions. 8. The method according to claim 7, in which the corresponding pair of sectors of the partition is found in the cells (10, 14), which should be placed in positions relative to each other, similar - by analogy with a game of chess, while the cells of the cell scheme correspond to checkerboard positions - given position of the horse and its area of movement. 9. The method according to claim 1, in which the division of the sectors and the re-distribution of channels of all successive transition stages are performed in the same way for all cells according to this pair of corresponding 90 ° sectors of the first and third (6, 8) cell types, respectively, or the second and the fourth (7, 9) type of cells, respectively. 10. The method according to claim 1, in which the first cell scheme is placed with the first type (6) of cells having the first channel (a) distributed for sectors of the opposite direction, and the second channel (B) distributed for sectors of the opposite direction, and the second type (7) of cells having the same channel distribution as the first type cells, but located with a rotation of 90 ° relative to the first type of cells, and the first and second type of cells are placed in an alternating manner along the first line, a third type (8) of cells having a third channel (b) distributed for sectors of the opposite direction, and a fourth channel (A) distributed for sectors of the opposite direction, and a fourth type (9) of cells having the same channel distribution as the third type cells, but located with a rotation of 90 ° relative to the third type of cells, and the third and fourth type of cells are placed in an alternating manner along the second line, moreover, the first (6) and third (8) cell types are placed in an alternating manner along the third line. 11. The method according to any one of claims 1 to 10, in which the second cell scheme is characterized in that a particular channel is allocated for an even number of sectors per cell, the same channel (a, b; A, B) is not allocated for the corresponding sectors (*) of all four types of cells, the same channel (a, b; A, B) is not allocated for adjacent sectors (X) of any type of cells, the same channel (a, b; A, B) is not allocated for a particular sector of any given type of cells and the adjacent sector (#) of any other type of cells for the corresponding sector of a particular sector found in the directions of the boundaries of a particular sector.

Images