JP2002064858A - Multicell system and base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a space utilization factor of a frequency in a multicell system having base stations arranged on a line, the base stations repeatedly using an up frequency and a down frequency. SOLUTION: In the base station, the down frequency is reused on the line as the up frequency, and the up frequency is reused on the line as the down frequency. When a transmit/receive antenna of a mobile station has directivity to the direction of the base station, in the case where a transmit/receive antenna of the base station has directivity to the direction of the mobile station, a subsequently transmitted signal on a line of a signal is switched between up and down, resulting in lower received power as compared with the absence of switching. Therefore, it is possible to improve CIR of a received signal in the base station and receiving station and to increase a space utilization factor of a frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a mobile communication system in a continuous area where a plurality of base stations are arranged linearly on a road or the like, and each of the base stations travels linearly due to the overlap of the communication areas formed by the base stations. The present invention relates to a multi-cell system that provides

2. Description of the Related Art As a conventional multi-cell system for providing a linear continuous communication area, there has been a multi-cell system in which base stations to which frequencies are repeatedly assigned in the same pattern are continuously arranged along a road. As these multi-cell systems, for example, Japanese Patent Application Laid-Open No. 10-10823
There is No. 7.

[0002] Hereinafter, a conventional example will be described with reference to the drawings. FIG. 7 is a configuration diagram of a conventional multi-cell system. 7, 71 is a control station, 72 is a base station A, 73 is a base station B, 74 is a base station C, 75 is a base station D, 76 is a mobile station, and 77 is a road.

[0003] With respect to the conventional example configured as described above,
Hereinafter, the operation will be described. As shown in FIG. 7, in the conventional example, by continuously arranging the base stations so that the communication areas of the respective base stations overlap with each other, the mobile stations moving on the road are in a continuous area. Provide communication. In the communication area of the base station A, the mobile station performs bidirectional communication with the base station A, and in the communication area of the base station B, the mobile station performs bidirectional communication with the base station B. In these multi-cell systems, usually, a plurality of frequencies are prepared,
Adjacent base stations use different frequencies to avoid interference.

[0004] The same frequency is reused in a base station which is far away to some extent and which is less susceptible to radio wave interference. Here, the number of repetition zones is 3, and the frequency F1 used in the base station A is reused in the base station D which is three places away. Thus, F1, F2, F3, F
By continuously arranging base stations to which frequencies are assigned in a pattern of 1, F2, F3, F1,..., It is possible to realize a multi-cell system that provides mobile stations with communication in a continuous area.

[0005]

However, the above configuration has the following problems. In the conventional technology, base stations using the same frequency need to prepare a number of frequency channels for repetition and install them sufficiently apart so as not to interfere with each other. There were drawbacks that could not be done. In view of the above, an object of the present application is to increase the spatial utilization rate of a frequency in a multi-cell system that provides communication in a linearly continuous area.

[0006]

A multi-cell system according to a first aspect of the present invention communicates with a mobile station by arranging a plurality of base stations which are repeatedly reused from a finite number of frequencies on a line. In a multi-cell system in which a base station communicates with a mobile station using a frequency division duplex (hereinafter abbreviated as FDD), a frequency used as a downlink frequency in the base station is used as an uplink frequency when it is reused next time. The frequency used as the uplink frequency is used as the downlink frequency when it is reused next time.

Thus, in the multi-cell system according to the first aspect of the present invention, when the transmitting / receiving antenna of the mobile station has directivity in the direction of the base station that performs communication, or when the transmitting / receiving antenna of the base station communicates in the direction of the mobile station that performs communication. In the case of having directivity to the base station and the reception of the signal of the mobile station, if the next transmission signal on the line of the signal is not exchanged because the uplink frequency and the downlink frequency are exchanged , The received power is reduced. Accordingly, CIR (Ca), which is the power ratio between the desired wave and the interference wave in the base station and the mobile station
rrier to Interference power Ratio) can be improved, and the spatial utilization of frequency can be increased.

Further, the multi-cell system according to the second invention of the present application communicates with a mobile station by arranging a plurality of base stations which are repeatedly reused from a finite number of frequencies on a line, and the base station communicates with the mobile station. Time division duplex method (hereinafter TD)
D) and communicates with the mobile station in the base station, when the base station re-uses the downstream communication time as the upstream communication time, and uses the upstream communication time as the next reuse time. This is used as the downstream communication time.

Thus, in the multi-cell system according to the second aspect of the present invention, when the transmitting / receiving antenna of the mobile station has directivity in the direction of the base station that performs communication, or when the transmitting / receiving antenna of the base station communicates in the direction of the mobile station that performs communication. In the case of having directivity to the base station and the signal of the mobile station, the next transmission on the line of the signal is not exchanged because the upstream communication time and the downstream communication time are exchanged. The received power decreases as compared with the case. Therefore, the CIR, which is the power ratio between the desired wave and the interference wave in the base station and the mobile station, can be improved, and the spatial utilization of the frequency can be increased.

[0010]

Embodiment 1 Hereinafter, a multi-cell system according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a multi-cell system according to Embodiment 1 of the present invention.
In FIG. 1, 11 is a control station, 12 is a base station A,
13 is a base station B, 14 is a base station C, 15 is a base station D, 1
6 is a base station E, 17 is a base station F, 18, 19 are mobile stations,
110 is a road.

The operation of the multi-cell system according to the first embodiment configured as described above will be described below. As shown in FIG. 1, in the multi-cell system according to the first embodiment, the area of each base station overlaps along road 110 at intervals of, for example, 100 m, which is smaller than the communication area of a single base station. , A plurality of base stations are arranged. Thereby, the mobile station traveling on the road 110 can continuously communicate with the base station. Each base station is connected to the control station 11 by wire, and each base station is centrally controlled by the control station.

Each base station communicates with the mobile station using the uplink and downlink as separate frequencies. That is, in the present embodiment, the uplink and downlink duplex systems are FDD. Base station A
Uses F1 as the uplink frequency and F2 as the downlink frequency. The base station B adjacent to the base station A uses F3 as the uplink frequency and F4 as the downlink frequency. Next, the base station C reuses the combination of the uplink frequency and the downlink frequency used by the base station A, but uses the uplink frequency and the downlink frequency in the opposite manner to the base station A. That is, at the base station C,
F2 is used as the up frequency and F1 is used as the down frequency. Similarly to the base station C, the base station D reuses the combination of the uplink frequency and the downlink frequency used by the base station B, but uses the set opposite to the base station B. Further, the base station E uses the same combination of the uplink frequency and the downlink frequency as the base station C, and uses the same uplink frequency F1,
The downlink frequency F2 is used.

In the above configuration, when the same frequency is reused, the uplink frequency and the downlink frequency are exchanged so that the transmitting / receiving antenna of the mobile station has directivity in the direction of the base station with which communication is performed. Alternatively, when the transmitting / receiving antenna of the mobile station has directivity in the direction of the base station with which communication is performed, the CIR can be improved, the frequency reuse distance can be shortened, and the frequency spatial utilization rate can be reduced. Can be enhanced. Details will be described later.

Next, the configurations of the base station and the mobile station according to the present embodiment will be described. FIG. 2 is a diagram showing a configuration of a mobile station and a base station in the multi-cell system according to the first embodiment. In FIG. 2, reference numeral 21 denotes a mobile station;
Antenna 211, duplexer 212, switching device 21
3. Receiving device 214, transmitting device 215, control device 216
And 22 is a base station, and an antenna 221,
Duplexer 222, receiving device 223, transmitting device 22
4, a control device 225 and a wired transmission / reception device 226.

The mobile station 21 communicates with an antenna 211, a duplexer 212 that separates a high frequency group component and a low frequency group component, and a high frequency group component and a low frequency group component. Connection to the reception device 214 or the transmission device 215
Switching device 213 for switching whether to connect to the antenna, antenna 2
Receiving device 21 for receiving data from a base station by using
4. Transmitting device 215 for transmitting data to the base station using antenna 211, receiving device 214 and transmitting device 21
5 and a control device 216 for transmitting and receiving data to and from the base station 22 in a predetermined procedure. The receiving device 214 needs to switch the frequency according to the downlink frequency of the base station with which communication is currently being performed. The control device 216 controls the receiving device 214 to switch the frequency. Similarly, the transmitting device 215 needs to switch the frequency in accordance with the uplink frequency of the base station with which communication is currently being performed, but the control device 216 controls the transmitting device 215 to switch the frequency. The duplexer 212 separates the components of the high group of frequency channels and the components of the low group of frequency channels. When the transmission frequency is high and the reception frequency is low, the control device 216 switches so that the transmission device 215 is connected to the high frequency side of the duplexer 212 and the reception device 214 is connected to the low frequency side of the duplexer 212. Device 21
Switch 3 When the transmission frequency is low and the reception frequency is high, the control device 216 switches the switching device 213 so that the connection is reversed.

The base station 22 includes an antenna 221, a duplexer 222 for separating high frequency and low frequency, and an antenna 221.
Receiving device 223 for receiving data from the mobile station using
A transmitting device 224 for transmitting data to the mobile station using the antenna 221, a data transmitting / receiving device using the receiving device 223 and the transmitting device 224 to perform data transmission / reception in a predetermined procedure, and the wired transmitting / receiving device 226. A control device 225 communicates with the control station by using the control device, and a wired transmission / reception device 226 performs data transmission and reception with the control station. The base station 22 transmits and receives data to and from the control station by the wired transmission / reception device 226. The control station transmits data to be transmitted to the mobile station, receives data from the mobile station, and transmits control data to each base station.

Various communication schemes can be considered between the mobile station and the base station. For example, for example, the base station allocates an uplink slot in the uplink frequency and a downlink slot in the downlink frequency to the mobile station as needed. A more specific operation will be described below with a typical example of a method in which a mobile station transmits and receives data to and from a base station.

A handover process is required when a mobile station moves and changes the base station with which it communicates. The handover processing when a certain mobile station moves from the base station A to the base station B will be briefly described. Before the handover, the mobile station exists in the communication area of the base station A and has a transmission slot assigned at the uplink frequency F1 of the base station A;
Data communication is performed with the base station A in the reception slot allocated at the downlink frequency F2. It is assumed that each base station is transmitting a beacon slot, and the mobile station communicates with base station A and simultaneously receives a beacon slot signal of base station B, which is an adjacent base station, and The comparison of the radio wave intensity with the signal of the reception slot of the first embodiment is performed. The mobile station can know the frequency of the adjacent base station uniquely if the frequency repetition pattern is predetermined, or each base station notifies the mobile station of the frequency of the adjacent base station. It may be. The mobile station compares the radio wave intensity of the beacon slot from the base station B which is the adjacent base station with the reception slot from the base station A which is the current base station. When the radio field intensity of the reception slot of A becomes stronger, it is determined that the mobile station has entered the communication area of the base station B, and a handover request is made to the base station B. The base station B currently allocates an unused uplink slot at the uplink frequency F3 and an unused downlink slot at the downlink frequency F4 at the base station B, and assigns the timing of the new transmission slot and the timing of the reception slot to the base station A. Notify the mobile station via The mobile station communicates with the base station B using the timing of the new transmission slot and the timing of the reception slot.

The effect of improving the CIR by using the uplink frequency as the downlink frequency when reusing it again and using the downlink frequency as the uplink frequency when reusing it next will be described.

First, the directivity of the antennas of the base station and the mobile station according to the present embodiment will be described with reference to the drawings. FIG. 3 is a diagram illustrating an example of the directivity of the antenna of the base station in the multi-cell system according to the first embodiment. As shown on the right side of FIG. 1, the antenna of the base station is:
For example, it is assumed that it has the maximum gain in the downward direction of 45 °, and the angle with respect to the horizontal direction is indicated by θ. FIG. 3 shows the relationship between θ and the antenna gain in the base station.
On the other hand, the transmitting and receiving antennas on the mobile station side are omnidirectional antennas.

Based on such antenna gain, the CIR when the uplink frequency and the downlink frequency are exchanged and the CIR when the uplink frequency and the downlink frequency are not exchanged will be specifically compared.

FIG. 4 is an explanatory diagram for CIR calculation. In FIG. 4, 41 is a base station X, 42 is a base station Y,
43 is a base station Z, and 44 is a road. In FIG. 4, it is assumed that a base station X, a base station Y, and a base station Z are base stations using the same frequency. In FIG. 4, the distance between bases is R, and the distance between base stations using the same frequency is (N + 1).
・ R is indicated.

The CIR is calculated when the uplink frequency and the downlink frequency are not exchanged. First, the CIR of the downlink signal in the mobile station is calculated. The worst CIR of the downlink signal at the mobile station is at the mobile station located at point V in FIG. CIR of the downlink signal at this time
Г _1down is represented by the following equation. Г _1down = P ₁ / P ₂ = 20 · LOG ₁₀ (N + 2) (d
B) Here, P ₁ is the reception power of the downlink signal from the base station Y, and P ₂ is the reception power of the downlink signal from the base station Z. The propagation loss is a free space loss and is proportional to the square of the distance.
And the antenna gain in the direction of the mobile station of the V points in the base station Y, the antenna gain in the direction of the mobile station of the V points in the base station Z has been calculated as being equal at approximately G _A (see FIG. 3 ). Also, the received power P ₃ from the base station W at the mobile station at the point V is small and negligible compared to P ₂ because the antenna gain in the direction of the mobile station at the point V at the base station W is small.

Next, the C of the uplink frequency signal at the base station is
Calculate IR. The CIR of the uplink signal at the base station Y becomes the worst for the uplink signal from the mobile station at the point V in FIG. 4, and when the mobile station at the point U is transmitting the uplink signal in the same slot. . Г _iup, which is the CIR of the uplink signal at this time, is expressed by the following equation. Г _1up = P ₄ / P ₅ = 20 · LOG ₁₀ (N + 1) (d
B) Here, P ₄ is the base station X of the uplink signal from the mobile station at the point V.
, And P ₅ is the received power at the base station Y of the uplink signal from the mobile station at the point U. The antenna gain in the direction of the mobile station at point U at the base station Y;
Antenna gain in the direction of the mobile station of the V point is performing computed as equal approximately G _A in. The reception power of the uplink signal from the mobile station of W point communicates with the base station Y, because the antenna gain in the direction of the mobile station of the W point in the base station Y is small, smaller than the P ₅ It can be ignored.

Next, calculation is performed on the CIR when the uplink frequency and the downlink frequency are exchanged. First, the CIR of the downlink signal in the mobile station is calculated. As in the case where the uplink frequency and the downlink frequency are not switched, V
Calculate the CIR at the mobile station at the point.

The reception power P ₁ of the downlink signal from the base station X at the mobile station at the point V is represented by the following equation. _{P 1 = P 0b -20 · LOG} 10 (4πR / λ) + G A (d
B) Here, P _0b is the transmission power of the base station, and λ is the wavelength of the transmission radio wave.

As the maximum interference wave at the mobile station at the point V, an uplink signal from the mobile station at the point U and an uplink signal from the mobile station at the point W may be considered. The received power of the uplink signal from the mobile station at point U at the mobile station at point V is represented by P ₃
', Received power P ₂ of the uplink signal from the mobile station from point W
Then, these ratios α can be represented by the following equations. α = P ₂ ′ / P ₃ ′ = 20 · LOG ₁₀ ((N + 1) / N)
(DB) P ₂ ′ can be calculated as follows. P ₂ '= P _om -20 · LOG ₁₀ (4πR / λ) -20 ·
LOG ₁₀ (N + 1) (dB) Here, _Pom is the transmission power of the mobile station.

The sum of the reception powers P ₂ ′ and P ₃ ′ of the interference wave can be calculated as follows. P ₂ ′ + P ₃ ′ = 10 · LOG ₁₀ (10Ｐ (P ₂ ′ / 1
0) +10 ＾ ((P ₂ ′ + α) / 10))) = P _om −2
0 · LOG ₁₀ (4πR / λ) −20 · LOG ₁₀ (N +
1) + 10 · LOG ₁₀ (1 + 10 ＾ (α / 10))
(DB)

As described above, the C of the downlink signal of the mobile station at the point V when the uplink frequency and the downlink frequency are exchanged is described.
Г _2down which is IR can be represented by the following equation. Г _2down = P ₁ / (P ₂ ′ + P ₃ ′) = (P _ob −P _om ) + G
_A + 20 · LOG ₁₀ (N + 1) −10 · LOG ₁₀ (1+
10 ＾ (α / 10)) (dB)

Next, the CIR of the uplink signal at the base station Y
Is calculated. Similar to the case where the uplink frequency and the downlink frequency are not exchanged, the CIR is calculated for the uplink frequency signal from the mobile station at the point V in FIG. The received power P ₄ of the uplink frequency signal from the mobile station at the point V in the base station Y can be expressed by the following equation. _{P 4 = P 0m -20 · LOG} 10 (4πR / λ) + G A (d
B)

As the interference wave, a downlink frequency signal from the base station X and a downlink frequency signal from the base station Y may be considered. The received power P ₅ ′ of the downlink frequency signal from the base station X and the received power P ₆ ′ of the downlink frequency signal from the base station Z at the base station Y can be expressed by the following equations. _{P 5 '= P 6' =} P 0b + G B + G A -20 · LOG 10 (4π
(N + 1) R / λ) (dB)

Here, the directivity of the antenna of the base station X in the direction of the base station Y (transmission antenna gain at the time of calculation of P ₅ ′) and the directivity of the antenna of the base station Y in the direction of the base station Z (P ₆ ′ calculation) receive antenna gain when) is performing approximation as being approximately equal to G _B in Fig.

As described above, the CIR of the uplink signal at the base station Y when the uplink frequency and the downlink frequency are exchanged.
Г _2up can be expressed by the following equation. Г _2up = P ₄ / (P ₅ ′ + P ₆ ′) = (P _0m −P _0b ) +20
_{· LOG 10 (N + 1)} -G B -3 (dB)

From the above, when the uplink frequency and the downlink frequency are exchanged, the CIR improvement ratio of the downlink signal, G
_Down and the up ratio C _up of the uplink signal G _up can be expressed by the following equations, respectively. G _dowm = Г _2down / Г _1down = (P _0b −P _0m ) + G _A −2
0 LOG ₁₀ (1 + 1 / (N + 1))-10 LOG ₁₀
(1 + 10 ^ (α / 10) (dB) G up = Г 2up / Г 1up = (P 0m -P 0b) -G B -3 (d
B)

Accordingly, the condition that both G _dowm and G _up are 0 or more can be shown as follows. G _A > − (P _0b −P _0m ) + 20 · LOG ₁₀ (1 + 1 /
(N + 1)) + 10 · LOG ₁₀ (1 + 10 ＾ (α / 1
0)) _{where, α = 20 · LOG 10 (} (N + 1) / N) G B <(P 0m -P 0b) -3 Accordingly, when G _A, the G _B satisfies the above formula, upstream frequency and downlink frequency , The CIR of the downlink frequency at the mobile station and the CIR of the uplink frequency at the base station can be improved.

As specific numerical examples, N = 3, P _0b = P
_When calculation is performed for the case of _{0 m} (transmission power of mobile station = transmission power of base station), G _A > 6.4 G _B <−3.

These values can be realized in a normal directional antenna. For example, with a 5-element Yagi antenna, G _A = about 10 dB and G _B = about −10 dB can be realized, with G _dowm = 3.6 dB and G _up = 7.
The CIR of the downstream frequency signal is improved by about 4 dB, and the CIR of the upstream frequency signal is improved by about 7 dB.

As described above, in a multi-cell system that performs communication with a mobile station by performing communication with the mobile station by setting the uplink frequency and the downlink frequency to different frequencies and arranging base stations that repeatedly reuse the frequency in a linear manner. By using the frequency used as the downlink frequency at the base station as the uplink frequency when reusing it next time, by using the frequency used as the uplink frequency as the downlink frequency when reusing it next time, CIR of uplink frequency signal at base station and CI of downlink frequency signal at mobile station
R can be improved, and consequently the frequency space utilization can be increased.

In the present embodiment, the sum of the numbers of frequencies used as the uplink frequency and the downlink frequency is an even number, and the uplink frequency and the downlink frequency are paired. A description has been given of the case where the components are used interchangeably. However, the present invention is also applicable to a case where the total number of uplink and downlink frequencies is odd.

FIG. 5 is a configuration diagram of a multi-cell system in a case where the total number of frequencies used as uplink frequencies and downlink frequencies is an odd number. In FIG. 5, 51 is a control station, 52 is a base station A, 53 is a base station B, 54 is a base station C, 55 is a base station D, 56 is a base station E, 57 is a base station F, and 58 is a mobile station. Bureau 59 is a road.

As shown in FIG. 5, even when the total number of frequencies used as the uplink frequency and the downlink frequency is an odd number,
When the uplink frequency is used next, it can be configured as a downlink frequency, and when the downlink frequency is used next, it can be configured as an uplink frequency.
IR can be improved.

In this embodiment, the case where the antenna of the base station has directivity in the direction of the mobile station with which communication is performed has been described as an example. When the antennas of the mobile station and the base station both have directivity, the same effect can be obtained by replacing the uplink frequency and the downlink frequency when reusing them.

Although the present embodiment has been described by taking as an example the case where the uplink and downlink duplex systems in a certain base station are performed by FDD, the uplink and downlink duplex systems in a certain base station are described. The present invention is also applicable to a case where a time division duplex method is used.

FIG. 6 is a configuration diagram of a multi-cell system using TDD. In FIG. 6, 61 is a control station, 62 is a base station A, 63 is a base station B, 64 is a base station C, 65 is a base station D, 66 is a base station E, 67 is a base station F, and 68 is a mobile station. Bureau 69 is a road.

As shown in FIG. 6, when the frequency F1 used in the base station A is to be reused in the base station D, the uplink time domain and the downlink time domain are exchanged in the communication frame. use. In such a configuration, while the base station A is receiving an uplink signal, the base station D is transmitting a downlink signal. On the other hand, while the base station A is transmitting a downlink signal, the base station D is receiving an uplink signal. Therefore, as in the case of FDD, it is possible to improve the CIR of the uplink signal at the base station and the CIR of the downlink signal at the mobile station.

[0046]

As described above, according to the multi-cell system according to the first aspect of the present invention, by arranging a plurality of base stations which are repeatedly reused from among a finite number of frequencies on a line, a mobile station and a mobile station can be connected. In a multi-cell system where communication is performed and the base station communicates with the mobile station in the frequency division duplex system, the frequency used as the downlink frequency in the base station is used as the uplink frequency when it is reused next time, and as the uplink frequency. Since the used frequency is used as the downlink frequency when it is reused next time, when the base station receives the uplink frequency signal from the mobile station, the same frequency is used again on the line. However, since the signal is reused as a downlink frequency, the reception of an interference wave is reduced due to the directivity of the transmitting and receiving antennas as compared with the case of reuse as an uplink frequency. The power is reduced, and similarly, in the reception of the downlink frequency signal from the base station in the mobile station, when the same frequency is reused next on the line, it becomes an interference wave, but since it is reused as the uplink frequency, it is used as the downlink frequency. The reception power of the interference wave is reduced due to the directivity of the transmitting and receiving antennas compared to the case of reuse, and the transmitting and receiving antennas of the mobile station have directivity toward the base station that performs communication, or the transmitting and receiving antennas of the base station Can improve the CIR, which is the power ratio between a desired wave and an interference wave, at the base station and the mobile station, and can increase the frequency space utilization rate. effective.

According to the multi-cell system according to the second aspect of the present invention, a plurality of base stations, each of which is repeatedly reused from a finite number of frequencies, are arranged on a line to communicate with a mobile station, and In a multi-cell system in which a station communicates with a mobile station in a time-division duplex system, when the base station re-uses downstream communication time, it re-uses upstream communication time as upstream communication time. In this case, since it is configured to be used as the downlink communication time, in the uplink signal reception from the mobile station in the base station, if the same frequency is reused next on the line, it will be an interference wave,
Since the original uplink communication time is reused as the downlink communication time, the reception power of the interference wave is reduced due to the directivity of the transmitting and receiving antennas as compared with the case where the communication time is used as the uplink communication time. In the reception of a downlink signal from the base station in the mobile station, the same frequency is used next on the line, and the next reuse is an interference wave. However, since the downlink communication time is reused as the uplink communication time, the downlink communication time is The reception power of the interference wave is reduced due to the directivity of the transmitting and receiving antennas compared to the case where the transmitting and receiving antennas are used, and the transmitting and receiving antennas of the mobile station have directivity toward the base station for communication or the transmitting and receiving antennas of the base station Can improve the CIR, which is the power ratio of a desired wave and an interference wave at the base station and the mobile station, and improve the frequency space utilization rate, There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a multi-cell system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing configurations of a mobile station and a base station in the multi-cell system according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of directivity characteristics of a base station antenna in the multi-cell system according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram for CIR calculation.

FIG. 5 is a configuration diagram of a multi-cell system when the total number of frequencies used as uplink frequencies and downlink frequencies is an odd number;

FIG. 6 is a configuration diagram of a multi-cell system using TDD.

FIG. 7 is a configuration diagram of a multi-cell system in a conventional example.

[Explanation of symbols]

 11, 51, 61, 71 Control station 12, 52, 62, 72 Base station A 13, 53, 63, 73 Base station B 14, 54, 64, 74 Base station C 15, 55, 65, 75 Base station D 16 , 56, 66 Base station E 17, 57, 67 Base station F 18, 19, 21, 58, 68, 76 Mobile station 110, 44, 59, 69, 77 Road 211, 221 Antenna 212, 222 Duplexer 213 Switching device 214 223 receiving device 215 224 transmitting device 216 225 control device 22 base station 226 wired transmitting / receiving device 41 base station X 42 base station Y 43 base station Z

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor ▲ Taka ▼ Hitoshi Ikai 1006 Kadoma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 5K067 AA11 BB03 CC02 CC04 DD43 DD44 EE02 EE10 EE24 EE44 EE61 EE71 FF16 HH22 JJ54 KK02

Claims (8)

[Claims] 1. A multi-cell system for communicating with a mobile station by arranging a plurality of base stations that repeatedly reuse an uplink frequency and a downlink frequency from a finite number of frequencies, respectively, in a linear manner, wherein the base station Wherein the frequency used as the downlink frequency is used as the uplink frequency when it is reused next, and the frequency used as the uplink frequency is used as the downlink frequency when it is reused next. Multi-cell system. 2. A base station in a multi-cell system for communicating with a mobile station by arranging a plurality of base stations that repeatedly reuse an uplink frequency and a downlink frequency from a finite number of frequencies in a linear manner, A base station characterized in that a frequency used as a downlink frequency is used as an uplink frequency when it is reused next, and a frequency used as an uplink frequency is used as a downlink frequency when it is reused next. . 3. A multi-cell system for communicating with a mobile station by arranging a plurality of base stations that repeatedly reuse a finite number of sets of uplink and downlink frequencies in a linear manner, wherein the base stations have the same A multi-cell system characterized in that when a set of an uplink frequency and a downlink frequency is reused next time, the uplink frequency is reused as the downlink frequency and the downlink frequency is reused as the uplink frequency. 4. A base station in a multi-cell system for communicating with a mobile station by arranging a plurality of base stations that repeatedly reuse a finite number of sets of uplink and downlink frequencies in a linear manner, A base station characterized in that the next time a set of a downlink frequency is reused, an uplink frequency is used as a downlink frequency and a downlink frequency is used as an uplink frequency. 5. A plurality of base stations that repeatedly reuse an uplink and downlink common frequency from a finite number of frequencies and communicate with a mobile station by time division duplex at the common frequency. In the multi-cell system to be arranged, in the base station, when the common frequency is reused next, an uplink communication time in the base station is defined as a downlink communication time, and a downlink communication time is defined as an uplink communication time. A multi-cell system characterized by being used as time. 6. A plurality of base stations that repeatedly reuse an uplink and downlink common frequency from a finite number of frequencies and that perform time division duplex communication at the common frequency are linearly arranged. A base station in a multi-cell system that communicates with a mobile station according to the following, when the common frequency is reused next, an uplink communication time in the base station is defined as a downlink communication time, and a downlink communication time is defined as A base station characterized by being used as uplink communication time. 7. The antenna according to claim 1, wherein the antenna of the base station or the antenna of the mobile station has directivity.
A multi-cell system according to any one of the above. 8. The antenna according to claim 2, wherein the antenna of the base station or the antenna of the mobile station has directivity.
The base station according to any one of the above.