JPS60106238A - Constitution system for mobile communication radio zone - Google Patents

Abstract

PURPOSE:To reduce interference of the same frequency by dividing all radio channels into plural groups, further dividing them into small groups of plural radio channels, and allocating all or some of channels in the same small group to radio zones at the shortest specific distance. CONSTITUTION:When the number of repetitive zones is seven, two groups are regarded as A and B and the frequencies of both groups are divided into seven equal to the number of zones, i.e. 1a-7a and 1b-7b (1a and 1b, etc.: singular or plural radio channels). The radio zone (2a, 1b) at the center part encircled with a thick line uses the frequencies of 1a in the group A and 1b in the group B, and numbers in other radio zones show frequency allocation; and there are 12 radio zones encircled with thick lines as the closest radio zone which uses the same frequency channel with the radio zone (2a, 1b) at the center part, and they are dispersed as compared with the normal number of zones, i.e. six, thereby reducing interference of the same frequency.

Description

[Detailed Description of the Invention] The present invention configures a service area with a plurality of wireless zones,
The present invention also relates to a zone configuration method that can reduce interference caused by the same frequency in other wireless zones in a mobile communication system that repeatedly uses a channel of the same frequency in each wireless zone separated by a certain distance or more.

In mobile communication systems that require effective use of limited frequencies, the service area consists of multiple wireless zones, and channels with the same frequency (hereinafter referred to as the same channel) are used in wireless zones that are separated by a certain distance. is common.

``The distance between wireless zones that use the same channel is determined so that co-channel interference is below the allowable value.In general, the co-channel interference allowable value is expressed as the signal level ratio of the desired wave to the interference wave.Wanted wave to interference A system that tolerates a low wave signal level ratio can use the same channel repeatedly over close distances, and thus can increase frequency utilization.

Figure 1 is a diagram showing an example of frequency repetition, and is a hexagonal -
The encircled areas represent wireless zones, and wireless zones with the same number indicate that the same channel is used. use the same channel. The same applies to 2 to 7. In the figure, the area surrounded by a thick line is the largest of the combinations of wireless zones that use channels of different frequencies, and in this example is made up of seven wireless zones. A service area of any size can be constructed by overlapping the areas indicated by the thick lines while shifting the area.

Hereinafter, the area indicated by the thick line in Figure 1 will be referred to as the basic repeating unit area, and the number of wireless zones within it will be referred to as the number of repeating zones.
Once the distance between wireless zones that allows the same channel to be used repeatedly is determined, the number of repeated zones is uniquely determined.

Radio wave propagation characteristics in mobile communications depend on the movement (movement) of the mobile station.
Generally, complex fluctuations are observed. It was stated that the distance between wireless zones that use the same channel is determined so that co-channel interference is below the allowable value, but this does not mean that it is satisfied on average, but locally due to propagation fluctuations, interference * There may be places where the requirements are not met.

In the case of interference in the line from the mobile station to the base station (hereinafter referred to as the upper line), the mobile station using the channel receiving the interference (hereinafter referred to as the desired wave mobile station) and the mobile station causing the interference (hereinafter referred to as the desired wave mobile station) Since the interfering wave mobile stations (hereinafter referred to as interfering wave mobile stations) are located in different locations, the location of the desired wave mobile station that cannot satisfy the interference condition is not specified. Furthermore, even in the same location, the amount of interference differs for each channel.

However, in the case of interference from the base station to the mobile station (hereinafter referred to as the lower 9 lines), the base station using the channel receiving interference (hereinafter referred to as the desired wave base station) and the base station causing the interference (hereinafter referred to as the desired wave base station) Since the interfering wave base station (hereinafter referred to as the interfering wave base station) is fixed in location, the interference condition is defined only by the location of the desired wave mobile station. In other words, when a mobile station arrives at a specific location, there is always a possibility that it will experience interference regardless of the channel used.

This means, for example, that some subscribers will inevitably experience interference near their homes, which is inconvenient for the service.Also, since the interference characteristics are the same even if the channels are different, A method of avoiding interference by detecting the amount of interference during communication and, if there is interference exceeding the allowable value, switching to a channel that is not in use within the same wireless zone (Patent Application No. 58-31482, Mobile Radio Communications channel control method) does not function effectively.

The present invention solves the above-mentioned drawbacks with respect to interference in the downlink by preventing poor communication due to fixed interference at a specific location and by varying the interference characteristics of the channel tune in the downlink. The purpose is to

If the service area is sufficiently wide, as can be inferred from Figure 1, if we focus on a certain wireless zone, the closest wireless zone that uses the same channel as that hot-wire zone is 60.
There are 6 for each 0.

Therefore, repeated use of frequencies can only be considered within one 6000 sector area.

Figure 2 shows the location of wireless zones that use the same channel,
It is a figure explaining the number of practice zones at that time. The above discussion only needs to be considered within the 600 fan-shaped area sandwiched by the semi-straight fats B and C. (The center of the wireless zone is C
Things that are on the line are considered to be included in the fan-shaped area, but things that are on line B are not included. ) In the figure, for example, when the same channel is used in the wireless zone labeled 9 and the wireless zone located at , the number of repeated zones is 9. There are no other wireless zones with the number 9, which means that when the number of repeating zones is 9, there is only one way to use it repeatedly.

There are two wireless zones marked 7, but this means that when the number of repetition zones is 7, the number of repetitions is 2.
It means that there is one.

Similarly, if we look at the number of repetition zones that have only one repetition method,
-1, 3, 4, 9, 12, 16, 25°27...
・・・・・・ The number of repetition zones with two repetition usage methods is -7, 1
3, 19, 21, 28, 37... The number of repeat zones with three repeat usage methods is -49,...
・・・・・・ The number of repetition zones with 4 repetition usage methods is -91,
・・・・・・・・・ It becomes.

Figures 3 and 4 are for the case of 7 repetition zones, 2
FIG. 2 is a diagram illustrating an example of a zone configuration when a standard frequency usage method is applied. Wireless zones with the same number in the figure use the same channel. The thick line is the repeating unit.

The MrJs diagram and FIG. 6 are diagrams showing an example of a zone configuration when the number of repetition zones is 13 and a frequency usage method of 9 times in duplicate is applied.

In the present invention, for example, the frequency assigned to the system is
Divide into groups and apply different repetition usage methods to each group as shown in Figures 3 and 4 (for 7 zone repetition) or Figures 5 and 6 (for 13 zone repetition). An embodiment of the present invention is shown in FIG. 7 for a case where the number of repetition zones is 7.

The two groups are respectively A group and B group, and the frequencies of both groups are divided into 7 equal to the number of repetition zones 7, 1a.

2a, 7a, 1b, 2b, ・Song number 7b. (La, Ib, etc. each represent a single or multiple wireless channels.) The unimaginable zone (2a, lb) surrounded by a thick line in the center of the figure uses the frequencies of 2a of group A and 1b of group B. means. The numbers in other wireless zones have the same meaning. Central part (2a, lb)
The closest wireless zones that use the same frequency channel as the wireless zone are the 12 wireless zones surrounded by bold lines.

That is, in a normal zone configuration, the number of closest co-channel wireless zones is 6, but in the present invention they are distributed into 12 zones. The same applies not only to the wireless zone (2a, lb) but also to all other wireless zones. FIG. 8 shows an embodiment in which the number of repetition zones is 13, and the frequencies are divided into two groups, and each group is further divided into 1a to 13a*1b to 13b and assigned to each radio zone. The wireless zones (2a, 6b) surrounded by thick lines in the center of the figure and the closest wireless zones that use the same channel are a total of 12 wireless zones surrounded by thick lines.

Although the case where the number of different frequency repetition usage methods is two has been described above, the same applies to the case where there are three or more frequency repetition usage methods such as 49 or 91 repetition zones. For example, if the number of repetition zones is 49, set the frequencies to A and B.

Divide into 3 groups of C, and further divide each into 1a to 49a,
Divided into 1 b ~ 49b, 1 c ~ 49c,
By applying three frequency repetition usage methods to each group, the number of nearest random zones using the same channel is 3x6=18.

By the way, the above method cannot be applied when there is only one frequency repetition usage method like 3.4 and 9.12.

An example of the present invention in this case will be shown below.

If repeated use is possible with the number of repetition zones N, select the minimum number M of repetition zones greater than N, and use the repetition zone N.
and M3ff are used in an overlapping manner. FIG. 9 is an example of N22, so M=12.

Divide the frequency into two groups, A and B, and further divide both groups into la and 2a.
,...9a.

It is divided into lb, 2b, music, and 12b and assigned to each wireless zone. (s a I 9 b ) in the center of the figure
The closest wireless zone that uses the same channel as the wireless zone is still 12.

In the present invention, it is also possible to use a combination of the first method and the second method. In this case, for example, if you use 9-zone repetition, which has only one repetition method, and 13-zone repetition, which has two repetition usage methods, the number of closest wireless zones that use the same channel will increase to (1 + 2) x 6 = 18 zones. .

The above explanation covers the case where exactly the same number of wireless channels are allocated to all wireless zones that use the same wireless channel, but there is a case where the number of wireless channels allocated is increased or decreased depending on the traffic in each wireless zone. However, the present invention can also be applied.

As described above, according to the present invention, the mantissa of each wireless zone is divided into a plurality of groups, and the radio zones that use channels of the same frequency as the mantissa of each group differ for each group. Therefore, the probability that interference will occur in a specific location on the lower channel is reduced to 1/th of the number of divided groups, and even if you are using a channel in a certain group and receive interference in a specific location, Interference can be reduced by switching to Nayair.

In addition, this method will become more effective even in the downlink, where the method of detecting interference and reducing it by switching to another radio channel has not worked effectively.

Therefore, in addition to improving serviceability for users who mainly use areas where conventional interference has been present,
Since interference reduction technology based on a method of detecting interference and switching to another channel can be applied to the lower line as well, there is an advantage that the frequency utilization rate can be improved.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of frequency repetition, Figure 2 is a diagram explaining the position of wireless channels that use the same channel and the number of repetition zones at that time, and Figures 3 and 4 are diagrams showing an example of frequency repetition. Figures 5 and 6 show examples of zone configurations when two frequency usage methods are applied in the case of 13 repetition zones. FIG. 7 is a diagram showing an embodiment of the present invention when the number of repetition zones is 7, FIG. 8 is a diagram showing an embodiment of the invention when the number of repetition zones is 13, and FIG. It is a figure which shows the Example of this invention in the case of several 9. Agent Patent Attorney Takashi Honma Figure 1 Figure 3 Figure 4 @ 5 Art Book Figure 6 Figure 7 A Figure q

Claims (1)

[Claims] In a mobile communication system where a service area is made up of multiple wireless zones and wireless channels of the same frequency are used in wireless zones that are separated by a predetermined minimum distance, the entire wireless channel is divided into multiple groups, and one group is Divide into a plurality of radio channel small groups in the east, and place all or some unrelated channels in the same radio channel small group in wireless zones separated by a predetermined shortest distance, and each other group is further divided into a plurality of radio channel subgroups, and all or some of the radio channels in the same radio channel subgroup are placed in an unrelated zone separated by a distance equal to or greater than the shortest distance. A mobile communication wireless zone configuration method that envisages arranging a plurality of groups of wireless channels in each wireless zone by arranging .