JPH10304436A - Mobile radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sufficient radio wave reception quality by distinguishing a frequency assigned to voice communication from a frequency assigned to data communication and assigning frequencies to each base station, so that a frequency repetition zone number for the frequency assigned to the voice communication is smaller than that assigned to the data communication. SOLUTION: Frequencies f1-f9 used for data communication and frequencies F10-F13 used for voice communication are assigned to base stations 11 -164 in radio zones 21 -264 . The frequencies f1-f9 used for the data communication repeat a same frequency for each of 9 zones in a hatched regions and the frequencies F10-F13 used for the voice communication repeat the same frequency for each of 4 zones in regions within a thick line frame. Thus, sufficient communication quality is obtained, even around borders of the radio zone 2 in the data communication and the utilizing efficiency of the frequency in the service area 3 is improved for the voice communication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention covers a service area with a plurality of radio zones, and allows a base station constituting each radio zone and a mobile station located in the radio zone constituted by the base station to communicate with each other. The present invention relates to a mobile radio communication system for performing communication, and particularly relates to effective use of a frequency when voice communication and data communication are mixed in a service area.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional mobile radio communication system having a multi-zone configuration shown in Chapter 7 of "Mobile Communication" (editor: Masaaki Shinji, issued by Maruzen Co., Ltd., September 1989). FIG. In FIG, ₁ 1 to 1 ₉ base station, 2 ₁ to 2 ₉ can receive radio waves at a predetermined quality from the base station ₁ 1 to 1 ₉ respectively range, i.e. the base station 1 ₁
This is a wireless zone composed of ~ ₁₉ . 3 was constructed seamlessly covered by the plurality of radio zones 2 ₁ to 2 _9, a service area of a schematic of the mobile radio communication system. Also, 4 ₁ and 4 ₂ are mobile to move the respective service area 3, here, are illustrated for when located radio zone 2 ₂ and the wireless zone 2 _6.

FIG. 5 is an explanatory diagram schematically showing a zone configuration of a mobile radio communication system configured as shown in FIG. In FIG. 5, 64 base stations ₁₁ to 1 are connected.
₆₄ (in the drawing only the sign display those necessary for explanation) shows an example that covers the service area 3 by the wireless zone 2 ₁ to 2 ₆₄ configured in. Area indicated by the square in the figure is a wireless zone 2 ₁ to 2 ₆₄ in which the base station 1 ₁ to 1 ₆₄ in the center of each region constituting the base station 1 ₁ is a radio zone 2 _1, base station 1 ₂ is a wireless zone 2 ₂ .
The base stations 1 ₆₄ constitute the wireless zone 2 ₆₄ respectively.
In the figures, only those necessary for description are indicated by symbols,
Otherwise, the reference numerals are omitted. In addition, mobile unit 4 ₁
And _{4. 2} shows a case which is located in the radio zone 2 ₂₈ and 2 _31. For each base station, wireless zone, and mobile station, a specific suffix is not specified, and the suffix is deleted from the code display when indicating the general one.

Here, since the radio wave from the base station 1 is affected by the terrain and the building, the range of the radio wave actually has a complicated shape, but here, the intensity of the radio wave from a certain base station 1 depends on the base station. It is assumed that they are equal on a concentric circle centered on the station 1.
In this case to cover regularly in the radio wave arrival range of the gap without any of the base station 1 to the service area 3, the same intensity of the radio wave of the base station 1 _10, 1 _11, 1 _18, 1 ₁₉ in FIG. As shown by a circle, the reach of radio waves between adjacent base stations 1 needs to overlap, and the equal electric field lines at which the strengths of radio waves between adjacent base stations 1 are equal to each other are set at the end of the zone. Each wireless zone 2 is constituted by an equilateral triangle, square, or equilateral hexagon. In FIG. 5, wireless zone 2
Is a square, and the base stations 1 are regularly arranged so that the wireless zones 2 are in contact with each other to form a wide service area 3.

Next, the operation will be described. Wireless zone 2
Mobile unit 4 ₁ located within ₂₈ communicates voice or data between the base station 1 _28. The communicating voice or data between the mobile station 4 ₂ base station 1 ₃₁ similarly located in the radio zone 2 _31. In this manner, the mobile device 4 located at an arbitrary position in the service area 3 can communicate with the base station 1 constituting the wireless zone 2 covering the position at the frequency designated by the base station 1. .

[0006] In the mobile radio communication system having such a zone configuration, in each radio zone 2 in the service area 3, the frequency can be repeatedly used in a fixed repetition pattern, whereby the frequency can be used effectively. There is. F1 to f18 shown in FIG. 5 show examples of frequencies assigned to the base station 1 forming each wireless zone 2 for communication with the mobile station 4.
In this example, two types of frequencies are allocated to each wireless zone 2 and the base stations 1 using the same frequency are allocated so as not to be adjacent to each other in order to avoid radio wave interference, so that 18 types of frequencies f1 to f18 are allocated. By 6
It covers the entire service area 3 consisting of four zones.
Therefore, according to the illustrated embodiment, the mobile station 4 ₁ and the mobile station 4
₂ The base station 1 ₂₈ or the base station 1 _31, the same frequency f
1 can be used to communicate independently of one another.

In FIG. 5, the same frequency allocation is repeated in units of nine zones surrounded by a thick line in the figure, and this is generally expressed as nine frequency repetition zones. doing. The smaller the number of frequency repetition zones, the higher the frequency utilization efficiency. However, since the distance of the base station 1 that causes frequency interference to the mobile device 4 becomes shorter, the reception quality of radio waves near the boundary of the wireless zone 2 is reduced.

[0008] Here, assuming a case where voice communication and data communication coexist as a communication type between the base station 1 and the mobile station 4 in the service area 3, generally, the bit error rate is low in voice communication using the digital transmission system. If it is about 10-2 or less, required communication quality (voice quality) can be obtained. on the other hand,
In data communication, a bit error rate of about 10-5 or less is generally required. This means that the reception quality of radio waves to be guaranteed on the boundary line of the wireless zone 2 differs between the case of voice communication and the case of data communication. Therefore, in a mobile radio communication system in a zone arrangement originally designed for voice communication, it is not possible to obtain radio wave reception quality such that good data communication quality can be obtained near the boundary of the radio zone 2. Further, in a mobile radio communication system in a zone arrangement originally designed for data communication, the reception quality of radio waves becomes excessive for voice communication even near the boundary of the radio zone 2, and the frequency is used efficiently. You will not be able to do it.

[0009]

Since the conventional mobile radio communication system is configured as described above, in a mobile radio communication system in which the number of frequency repetition zones is set to be small, even if the frequency can be effectively used, Near the boundary of the wireless zone 2, reception quality of radio waves sufficient for data communication cannot be obtained. On the other hand, in a mobile wireless communication system in which the number of frequency repetition zones is set large, voice communication is also performed near the boundary of the wireless zone 2. However, there has been a problem that the reception quality of radio waves becomes excessively high and the efficiency of frequency use cannot be sufficiently improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. When voice communication and data communication are mixed in a service area, sufficient radio wave reception quality can be obtained in each communication. An object of the present invention is to obtain a mobile radio communication system having high frequency use efficiency.

[0011]

A mobile radio communication system according to the first aspect of the present invention distinguishes between a frequency allocated for voice communication and a frequency allocated for data communication.
The frequency is allocated to each base station so that the number of frequency repetition zones of the frequency allocated for voice communication is smaller than that of the frequency allocated for data communication.

In the mobile radio communication system according to the second aspect of the present invention, a request for a new voice communication occurs when all of the frequencies for voice communication among the frequencies allocated to the radio zone are in use. In such a case, the allocation of a vacant data communication frequency to the voice communication is permitted.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is an explanatory diagram schematically showing a zone configuration of a mobile radio communication system according to Embodiment 1 of the present invention. In the figure, ₁₁ to ₁₆₄ are base stations,
In the figure, ₁ 1, 1 _2, 1 _9, 1 _28, 1 ₃₁ and 1 _64,
Except is omitted code displayed, from right in FIG Hidarihe, also from top to bottom, and 1 _1, 1 _2, ..., 1 ₆₄ order. The 2 ₁ to 2 ₆₄ surrounded by a broken line in the figure is a wireless zone constituted square at the base station ₁ 1 to 1 _64, respectively, 2 ₁ in the drawing, ₂ 2, 2 _28, 2 ₃₁ , and 2 ₆₄ except the sign display are omitted, 2 ₁ a radio zone the base station 1 ₁ is configured, 2 ₂ radio zone the base station 1 ₂ constitutes, ..., base station 1 ₆₄ Will be referred to as 2 ₆₄ . The 3 surrounded by the chain line in the figure consists covered with these radio zones 2 ₁ to 2 _64, a service area of the mobile radio communication system. 4 ₁ and 4 ₂ are service areas 3 respectively.
A mobile device that moves inside, where the wireless zone 2 ₂₈
And exemplifies a case located in the radio zone 2 _31.

Note that f1 to f9 and F10 to F13 shown in each of the wireless zones 2 ₁ to 2 ₆₄ correspond to the corresponding base station 1.
Is one example of frequencies assigned to ₁ to 1 _64, a frequency f1~f9 the frequency used for data communication, F10～F
Reference numeral 13 is assigned as a frequency used for voice communication. Normally, a plurality of frequencies are allocated to the frequency for data communication and the frequency for voice communication in accordance with the traffic of each wireless zone 2. However, in order to simplify the drawing and the description, only one frequency is used here. Is assigned.

In the example shown in FIG. 1, the frequencies f1 to f9 assigned for data communication repeat the same frequency every nine zones as shown by the hatched area for each unit. On the other hand, the frequencies F10 to F13 allocated for voice communication are used as base stations constituting each wireless zone 2 so that the same frequency is repeated for every four zones as indicated by a region surrounded by a thick line frame for each unit. Assigned to station 1. That is, the number of frequency repetition zones of frequencies allocated to data communication is 9, and the number of frequency repetition zones of frequencies allocated to voice communication is 4, which is smaller than that.

Next, the operation will be described. In the mobile radio communication system in which the zone arrangement and the frequency allocation are performed, when the base station 1 and the mobile device 4 start communication, the base station 1 determines whether the communication type is the data type in a call connection control stage normally performed. check whether the voice communication or a communication, in the case of data communication, the frequency base station 1 is allocated for data communication in a wireless zone 2 constituting (e.g., wireless zone 2 ₁ In this case, the frequency f1) is assigned to the communication. On the other hand, in the case of voice communications, the frequency (e.g., frequency F10 in the case of radio zone 2 ₁₎ assigned for the voice communication to the wireless zone 2 assign for that communication.

Next, the reception quality of the radio wave of the mobile communication by the zone configuration will be described. Here, the case where the base station 1 transmits and the mobile station 4 receives is described as an example. Mobile device 4
Is one of the factors that determine the reception quality of the radio wave at the reception terminal of the mobile device 4, the ratio of the reception power C of the radio wave from the base station 1 of the communication partner to the noise power N due to thermal noise at the reception terminal, That is, it is a CN ratio. Base station 1
If a radio wave is radiated using an omnidirectional antenna, the CN ratio at the receiving terminal of the mobile device 4 located at a distance dm from the base station 1 is expressed by the following equation (1).

[0018]

(Equation 1)

Here, A is a constant determined by the transmission power of the base station 1, the height of the antenna, the frequency, and the like, and α is generally called an attenuation constant, and the strength of the radio wave depends on the distance from the base station 1. Is a constant representing the degree of attenuation
A degree value is used. N4 is the noise power at the receiving terminal of the mobile device 4.

Another factor that determines the reception quality of the radio wave in the mobile device 4 is that the reception power C of the radio wave from the base station 1 of the communication partner at the receiving terminal of the mobile device 4 is the same as the peripheral power that uses the same frequency at the same time. Is the ratio to the interference wave power I at the same reception terminal from another base station 1, that is, the CI ratio. For example, the mobile station 4 ₁ of the base station 1 ₂₈ and the data communication using the frequency f1 in FIG. 1, also radio waves from other mobile unit 4 ₂ and the base station 1 ₃₁ in the data communication using the same frequency f1 simultaneously Will receive it. Telecommunications of the same frequency from the base station 1 ₃₁ to the mobile unit 4 ₁ is an interference wave. Reception power C from the base station 1 ₂₈ in the receiving terminal of the mobile unit 4 ₁
When the ratio of the interference power I ₃₁ from the base station 1 ₃₁ is represented by the following formula (2).

[0021]

(Equation 2)

Here, A ₂₈ and A ₃₁ correspond to A in the formula (1).
Corresponds to a constant relating to the radio zone 2 ₂₈ or radio zone 2 _31, d ₂₈ is the distance between the base station 1 ₂₈ and the mobile unit 4 _1, d ₃₁ is the base station 1 ₃₁ and the mobile unit 4 ₁ Is the distance between them.

The mobile station 4 ₁ base station 1 ₄ and the base station 1 ₂₅ using the same frequency f1 simultaneously the base station 1 _28, 1 _31,
Since interference waves from _{152 and the} like are also received, the total reception power of the interference waves is the sum of these. Also, constants A ₂₈ and A
_{Let 31 be} equal for all wireless zones 2,
CI ratio at the receiving end of the mobile device 4 ₁ is represented by the following formula (3).

[0024]

(Equation 3)

[0025] However, in the above formula (3), the right side of the denominator shall represent a normalized value of the sum of the interference power at constant A for the mobile station _1.

Generally, the reception quality of radio waves in the mobile unit 4 is determined by both the CN ratio and the CI ratio at the reception terminal of the mobile unit 4 as described above. Then, the quality of communication (error rate of transmission bit, etc.) is determined based on these reception qualities. Therefore, as can be seen from both Expressions (1) and (3), as the mobile station 4 approaches the communication partner base station 1 in each wireless zone 2, the CN ratio and the CI ratio increase, and the reception quality of the radio wave increases. Will be better. Conversely, the reception quality of the radio wave deteriorates as the distance from the base station 1 increases, but even at the end of the wireless zone 2, that is, on the boundary with the adjacent wireless zone 2, the minimum reception required to obtain the required communication quality is achieved. Zone design is performed for each of data communication and voice communication so that quality can be ensured.

That is, from the equations (1) and (3), in order to increase the CN ratio on the boundary line of the radio zone 2, the constant A should be increased by increasing the transmission power of each base station 1 or the like. It turns out that it is good. On the other hand, the deterioration of the reception quality due to the deterioration of the CI ratio given by the equation (3) is peculiar to the mobile radio communication system based on the zone configuration. It is understood that the number of zones should be increased. However, when the number of frequency repetition zones increases, as described above, the frequency use efficiency decreases.

When the number of base stations 1 causing the same frequency interference to the mobile station 4 is large, it is generally said that the influence of the numbers of the CN ratio and the CI ratio on the communication quality is almost the same. ing. In the normal zone layout design, the zone layout is performed so as to reduce the number of frequency repetition zones as much as possible in order to increase the frequency use efficiency in the service area 3. The ratio becomes smaller than the CN ratio, and the reception quality of radio waves can be ignored by the CN ratio and is often determined only by the CI ratio.

Therefore, in the first embodiment, in data communication requiring a strict bit error rate,
The number of frequency repetition zones is set to 9 to guarantee and guarantee the reception quality of radio waves on the boundary line of the wireless zone 2. For voice communication in which required communication quality can be obtained even if the reception quality of radio waves is relatively poor, the number of frequency repetition zones is set to As 4 smaller than that, the frequency is used efficiently.

As described above, according to the first embodiment,
The frequency allocated to voice communication and the frequency allocated to data communication are distinguished. For data communication, so that the number of frequency repetition zones is large, for voice communication,
Since the frequency allocation of each base station 1 is performed so as to reduce the number of frequency repetition zones, sufficient communication quality can be obtained even near the boundary of the wireless zone 2 in data communication, and the service area in voice communication. 3 has the effect of improving the frequency use efficiency.

Embodiment 2 In the first embodiment, the number of frequency repetition zones is set to 9 for data communication,
Although the case where the number of frequency repetition zones is set to 4 has been described for voice communication, the setting of the number of frequency repetition zones for data communication and voice communication is performed according to a difference in radio wave reception quality between data communication and voice communication. Various combinations are possible.

FIG. 2 shows such a second embodiment of the present invention.
FIG. 1 is an explanatory diagram schematically showing a zone configuration of a mobile radio communication system according to the first embodiment. The second embodiment exemplifies a case where the number of frequency repetition zones for data communication is 5, while the number of frequency repetition zones for voice communication is 4. Here, f1 to f5 in the drawing are frequencies allocated for data communication, and F6 to F9 are frequencies allocated for voice communication. Note that the way of assigning reference numerals in each part and the way of expressing the figures are the same as those in the first embodiment, and a description thereof will be omitted here.

As described above, also in the second embodiment, the number of frequency repetition zones of the frequency allocated to the voice communication is set to 4 which is smaller than the number of frequency repetition zones 5 of the frequency allocated to the data communication. The same effect as in the case of is obtained. The same applies to other combinations in which the number of frequency repetition zones of frequencies allocated to voice communication is smaller than the number of frequency repetition zones of frequencies allocated to data communication.

Embodiment 3 Embodiments 1 and 2 above
In the above, the case where the shape of the wireless zone is applied to a mobile wireless communication system having a square shape has been described. However, the present invention can be similarly applied to a mobile wireless communication system having a wireless zone of a triangular shape or a hexagonal wireless zone. FIG. 3 is a diagram schematically illustrating a zone configuration of such a mobile radio communication system according to Embodiment 3 of the present invention.

The third embodiment shows a case where the present invention is applied to a mobile radio communication system having a hexagonal radio zone. In this case, the number of frequency repetition zones for data communication is 7,
The number of frequency repetition zones for voice communication is set to four. Here, f1 to f7 in the drawing are frequencies assigned for data communication, and F8 to F11 are frequencies assigned for voice communication. Note that the way of assigning reference numerals in each part and the way of expressing figures are the same as those in the first embodiment, and a description thereof will be omitted.

As described above, even in the third embodiment in which the shape of the wireless zone 2 is different, if the number of frequency repetition zones of frequencies allocated to voice communication is made smaller than the number of frequency repetition zones of frequencies allocated to data communication. Thus, the same effect as in the first embodiment can be obtained.

Embodiment 4 FIG. In the above-described first to third embodiments, the voice communication is to allocate the used frequency from the frequencies allocated for the voice communication in advance, but when there is no available frequency allocated for the voice communication, Alternatively, it is also possible to allow the allocation of a vacant frequency among the frequencies allocated for data communication.

[0038] That is, for example, using a frequency F13 assigned as a voice communication to the base station 1 ₂₈ in FIG. 1,
Already when the voice communication is being performed, the mobile unit 4 in the speech communication configured radio zone 2 ₂₈ by the base station 1 ₂₈
When ₁ has moved, or the mobile unit 4 _1, such as by calling in a wireless zone 2 _28, a new voice communication request if occurred, has been assigned to the base station 1 ₂₈ for data communication If the frequency f1 is not in use, the frequency f1 to the mobile unit 4 ₁ voice communication request
Allow to be assigned.

Here, in the fourth embodiment as well, a plurality of frequencies are assigned as the frequency for data communication and the frequency for voice communication in accordance with the traffic of each wireless zone 2. For the sake of simplicity, only one frequency is assigned. Therefore, if assigned a plurality of frequencies each, when The already voice communication using the frequency F13 is being performed, as for voice communication to the base station 1 ₂₈ represented by the frequency F13 all assigned frequencies means that in use, the case where the frequency f1 is not in use, the base station at least one of the frequencies assigned to 1 ₂₈ for data communication represented by the frequency f1 This means that one is empty.

As described above, according to the fourth embodiment,
In a situation where all of the voice communication frequencies allocated to the wireless zone 2 are in use, if there is a vacancy in the data communication frequency, it is allowed to allocate it to voice communication. There is an effect that can be improved.

[0041]

As described above, according to the first aspect of the present invention, the frequency allocated to the radio zone is distinguished between the data communication and the voice communication, and the number of frequency repetition zones of the frequency allocated to the voice communication is determined. Since the frequency is allocated to the base stations constituting each wireless zone so as to be smaller than the number of frequency repetition zones allocated for data communication, sufficient radio wave reception quality at the boundary of the wireless zone in data communication. In the case of voice communication, there is an effect that a mobile radio communication system capable of improving the frequency use efficiency in the service area can be obtained.

According to the second aspect of the present invention, when all the frequencies for voice communication allocated in the corresponding wireless zone are used, and when the frequency for data communication is free, the voice communication is performed. In this configuration, the use of the frequency for data communication is permitted, so that the use efficiency of the frequency can be further improved.

[Brief description of the drawings]

FIG. 1 is a view illustrating a first embodiment and a fourth embodiment of the present invention;
FIG. 2 is an explanatory diagram showing a zone configuration of a mobile radio communication system according to the first embodiment.

FIG. 2 is an explanatory diagram showing a zone configuration of a mobile radio communication system according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a zone configuration of a mobile radio communication system according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a conventional mobile radio communication system.

FIG. 5 is an explanatory diagram showing an example of a zone configuration of a conventional mobile radio communication system.

[Explanation of symbols]

1 ₁ to 1 ₆₄ base station, 2 ₁ to 2 ₆₄ radio zones, 3 service area, 4 _1, 4 ₂ mobile.

Claims (2)

[Claims] 1. A base station configuring each of a plurality of wireless zones covering a service area, and a base station moving within the service area and configuring a presently located wireless zone. In a mobile radio communication system configured by a mobile station performing communication between the base station and the mobile station, perform voice communication by voice and data communication by data, and a frequency used for the voice communication, The frequency used for data communication is distinguished and assigned to each of the base stations configuring each wireless zone, and the number of frequency repetition zones of the frequency assigned for the voice communication is assigned for the data communication. A mobile radio communication system wherein a frequency is set to be smaller than the number of frequency repetition zones. 2. When a new voice communication request is made in a situation where all the frequencies allocated for voice communication are used in base stations constituting each wireless zone, data communication for data communication is performed. 2. The mobile radio communication system according to claim 1, wherein if there is a vacancy in the frequency assigned to the mobile communication system, the frequency for the data communication is allowed to be assigned to the newly requested voice communication.