JPH09238378A - Radio communication equipment and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use efficiently frequencies for the cellular system. SOLUTION: In a radio zone 1, mobile stations A, B make communication by using communication channels S1, S2 whose radio frequencies are f1, f2. In a radio zone 2, mobile stations E, F make communication by using communication channels S1, S2 whose radio frequencies are f3, f4. In the radio zone 1, mobile stations C, D make communication by using communication channels S3 whose radio frequencies are f1, f2 and S4 whose radio frequencies are f5, f6. In the radio zone 2, mobile stations C, D make communication by using communication channels S3 whose radio frequencies are f1, f2 and S5 whose communication channels are f5, f6. Since a radio wave is sent for only the communication channels for a time slot in use, different time slots of the same frequency are used between adjacent radio zones as above and then the radio wave is utilized effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device using a plurality of wireless zones, and more particularly to a wireless communication device suitable for mobile communication and a method thereof.

[0002]

2. Description of the Related Art Cellular communication is widely used in mobile phones, car phones and the like. In this cellular system, TDM (Time
Communication is performed by the division multiplex method, and TDMA (Tim (Tim) is performed from the mobile station to the base station.
e Division Multiple Accesses
Communication is often performed by the s) method.

FIG. 6 shows a state of mobile communication according to a conventional cellular system. In the figure, the first base station 1
0 is a base station that controls the wireless zone 1, and the second base station 1
Reference numeral 2 is a base station that controls the wireless zone 2. And the first
The base station 10 and the second base station 12 are connected to the control station 14. A base station is a station that simply transmits and receives radio waves,
Nothing is involved in the allocation of lines. on the other hand,
The control station (indicated by 14 in FIG. 6) performs line control, more specifically, frequency / channel (time slot) allocation.

The operation of the TDMA mobile radio network shown in FIG. 6 when the number of multiplex is 4 will be described below.

The first base station 10 has radio frequencies f1 and f2 specific to the first base station 10 and radio frequencies f5 and f6 and a radio frequency f which are shared with the second base station 12.
7 and f8 can be transmitted and received.

Further, the second base station 12 is the second base station 12
Specific radio frequencies f3 and f4 and the above-mentioned radio frequencies f5 and f6 that are shared with the first base station 10.
And radio frequencies f7 and f8 can be transmitted and received.

That is, the basic radio frequencies of the first base station 10 are f1 and f2, and the basic radio frequencies of the second base station 12 are f3 and f5. Where the frequency f
1 is used for so-called downlink communication from the first base station 10 to the mobile station, and the frequency f2 is from the mobile station to the first base station 1.
Used for so-called upstream communication. In this way, upstream and downstream communications are performed at a set of frequencies f1 and f2, and bidirectional telephone communications and the like are performed. As shown in FIG. 6, the first base station 10 and the mobile units A, B,
Communication between Cs is performed using this set of frequencies f1 and f2. The state of the time slots supported by the set of the frequencies f1 and f2 is shown in FIG. The figure shows an example in which the number of multiplexing is 4, for example. That is, the frames with the frequencies f1 and f2 are
It is divided into four time slots, and each time slot corresponds to one communication channel (also referred to as S channel). It should be noted that one of the four time slots is used as a control channel (also referred to as C channel) and is used for notification of communication channel allocation to each mobile station. This control channel is also used to convey a connection request from each mobile station to the base station.

This control channel is always transmitted from the base station, but it is not always necessary to send radio waves to other time slots (that is, communication slots) when communication is not being performed. However, in a system that is actually used, a dummy signal is often sent out even when communication is not performed for the purpose of facilitating synchronization.

As described above, the set of the radio frequencies f1 and f2 is used for upstream (communication from the mobile station to the base station) and for downlink (communication from the base station to the mobile station). Radio frequencies f1, f2, f3, f4, f5, f6,
The same applies to f7 and f8. f3 and f4 form one set, and f5 and f6 also form one set. And f7 and f8 also form one set. The appearance of these sets of time slots is shown in FIGS. 7 (b), (c), and (d). As shown in FIG. 7B, in the set of radio frequencies f3 and f4, the radio frequencies f1 and f
Similar to the two sets, one time slot is used as a control channel (C channel), and three time slots are used as communication channels (S channels (S1 to S3)) used for actual communication. Can be used. On the other hand, as shown in FIG. 7C, the radio frequencies f5 and f6
In this set, all four time slots are used as S channels. This is because the set of radio frequencies f5 and f6 is a frequency for extension. That is, in the wireless zone 1, C of the basic wireless frequencies f1 and f2
Using the channel, all mobile stations are assigned an S channel or issue a connection request. In other words, since one C channel is sufficient for one radio zone, the set of extension radio frequencies f5 and f6 does not include the C channel. The same applies to the set of extension radio frequencies f7 and f8, and the state of the time slots of this set is shown in FIG. 7 (d).

When there is no mobile station in the wireless zone 1, the upstream frequency f2 is not used at all. Furthermore, the radio frequencies f5 and f6 and the radio frequency f7,
f8 is used when a call connection request is further issued from the mobile station in a state where all the S channels of the radio frequencies f1 and f2 are used, or when a call connection request is made from another radio zone. Radio frequency for expansion. Therefore, when the time slots (S channels) of the frequencies f1 and f2 are still available, the radio frequencies f5, f6, f7, and f8 are not used in the radio zone 1.

The same applies to the wireless zone 2.
When there are no mobile stations in the wireless zone 2, the upstream frequency f4 is not used at all. Further, the radio frequencies f5 and f6 and the radio frequencies f7 and f8 are
If the communication channel (S channel) of f4 is still available, it is not used in the wireless zone 2.

The first base station 10 uses the control channel of the downlink frequency f1 to notify a specific mobile station that there is a call to that station, and specifies the time slot to be used. . As mentioned above, the control station performs the actual time slot allocation.
The base station simply sends its allocation information.
Each of the mobile stations A, B, C, D, etc. constantly monitors the control channel of the downlink frequency f1 and constantly checks whether or not there is a call to the own station. Then, when there is a call to the own station, a time slot to be used is also selected based on the content of the control channel, and thereafter, communication is performed using this time slot.

On the other hand, when each mobile station A, B, C, D, ... Wants to originate a call, it calls the first base station 10 using the control channel of the upstream frequency f2. Tell you that you want to occur. Then, the first base station 10 transmits the frequency f
One control channel is used to specify the time slot (S channel) to be used. As described above, the mobile stations A, B, C, D, etc. constantly monitor the control channel of the frequency f1, and the contents thereof, for example, "mobile station A should use the time slot T2", etc. The communication is started using the time slot T2 based on the contents of

The situation is the same in the wireless zone 2.
The second base station 12 uses the control channel of the downlink frequency f3 to notify the predetermined mobile station that there is a call, and each mobile station E, F, G, H, etc. uses the uplink frequency f4. The second base station 12 to the effect that a call is to be made.

The operations of the first base station 10 and the second base station 12 are performed based on an instruction from the control station 14. FIG.
Shows a flowchart showing the operation of the control station 14. First, in step S7-1, the control station 14
Is waiting for a line connection request signal, in other words, a line allocation request signal.

Next, in step S7-2, the waiting channel allocation request signal is received by the control station 14 via the first base station 10 or the second base station 12.

Next, in step S7-3, the mobile station that has output the line allocation request signal and the base station that controls the radio zone in which the mobile station exists are identified. Then, based on the grasp of the base station in step S7-3, it is checked in the next step S7-4 whether or not the request is via the first base station. As a result of the check, if the line assignment request is via the first base station 10, the process proceeds to step S7-5, and it is checked whether or not there is an empty channel on the frequency f1. Figure 7
As shown in (a), the frequency f1 has four time slots (T1, T2, T3, T4) in one frame.
However, since one is used as a control channel (C channel), there are three time slots that are actually applicable to communication: T2, T3, and T4 ((FIG. 7
See a)).

If there is an empty channel on the frequency f1 in step S7-5, the process proceeds to step S7-9 to allocate a line using the empty channel.

At step S7-10, the time slot S of the frequency f1 is newly added to the line allocation table.
1 is used by a predetermined mobile station A (or B, C, D, etc.). The control station 14 is provided with a line allocation table that stores information as to whether or not the time slot is used for each frequency set.

In this way, the lines are connected,
The processing shifts to step S7-1 again to shift to the signal waiting state.

On the other hand, in step S7-5, if there is no free channel in the frequency f1, the process proceeds to the next step S7-7, and the second base station 12 performs f5.
Is checked for use. As a result, if the second base station 12 is using the frequency f5,
The process proceeds to step S7-11, and the line connection is disconnected as a call loss. Then, after that, in step S7
The process returns to -1. Note that in FIG. 8, the use of the line is finished and the assignment is deleted from the line assignment table. Although the operation of the call termination process is not shown, this is an operation that is generally performed in the control device that performs the call origination process, and thus the description thereof is omitted.

If the second base station 12 is not using the frequency f5 in step S7-7, it is checked in the next step S7-8 whether or not there is an empty channel at the frequency f5. As a result, if there is no free channel, disconnection is performed in step S7-11, but if there is a free channel, the process proceeds to step S7-9 and line allocation is performed.

If it is determined in step S7-4 that the request is not from the first base station 10, that is, if the request is from the second base station 12, step S7.
The processing shifts to 7-12.

As for the processing after step S7-12, the same processing as the above-mentioned steps S7-5 to S7-10 and the like is performed.

First, in step S7-12, it is checked whether or not there is an empty channel at the frequency f3. As a result of this check, if there is a free channel, step S7-1.
In step 6, the line is allocated using the idle channel, and the line allocation table is updated in step S7-17. These operations are similar to those in steps S7-9 and S7-10. On the other hand, if there is no empty channel at the frequency f3 in step S7-12, the process proceeds to step S7-14. In this step S7-14, it is checked whether the first base station 10 uses the frequency f5. As a result of the inspection, if the frequency f5 is in use, the line is disconnected in step S7-11. If the first base station 10 is not using the frequency f5, it is checked in step S7-15 whether or not there is an empty channel at the frequency f5. As a result of the inspection, if there is a free channel, the process of allocating the line after step S7-16 is performed, and if there is no free channel, the line disconnection process in step S7-11 is performed.

Next, as shown in FIG. 6, the control station 14 has two base stations (first base station 10 and second base station 1).
An example of a specific operation when each channel is assigned to communication when 2) is connected and two wireless zones are handled by respective base stations (10, 12) will be described.

First, in the wireless zone 1, the mobile station A
When there is a connection request from the mobile station B to the mobile station B, the first base station 10
Is a radio frequency f1 as a communication channel (S channel),
Slots S1 and S2 of f2 are assigned as communication channels between mobile station A and mobile station B.

Specifically, the mobile station A uses the time slot T
2 and the mobile station B communicates with the time slot T3.
Use to communicate. The state of this allocation is shown in FIG. 7A described above.

Similarly, in the wireless zone 2, when the mobile station E issues a connection request to the mobile station F, the second base station 1
2 assigns time slots T1 and T2 of radio frequencies f3 and f4 as S channels.

Also in this case, similarly to the radio zone 1, the mobile station E communicates using the time slot T2 of the radio frequencies f3 and f4, and the mobile station F communicates using the time slot T3. The state of this allocation is shown in FIG.
Is shown in

Next, in the radio zone 1, the mobile station C
When there is a connection request from the mobile station D to the mobile station D, the first base station 10
Is a radio frequency f1 as a communication channel (S channel),
Since only the time slot T4 of f2 is insufficient, the extension radio frequencies f5 and f6 are used to generate the radio frequency f5,
Allocate time slot T1 of f6. In particular,
The mobile station C communicates using the communication channel S3 of the radio frequencies f1 and f2, and the mobile station D communicates using the communication channel S4 of the radio frequencies f5 and f6. The manner in which the time slot T1 of the radio frequencies f5 and f6 is allocated to the mobile station D is shown in FIG. 7C described above.

In this case, the slots S5, S6 and S7 of the radio frequencies f5 and f6 are unused as communication channels (S channels), and are transmitted as unused channels without being used. However, as described above, even in this unused channel, radio waves are transmitted by a certain dummy signal for the reason of facilitating synchronization.

From this state, in the wireless zone 2,
When there is a connection request from the mobile station G to the mobile station H, the second base station 12 supports the mobile station G and the mobile station H only by the time slot T4 of the radio frequencies f3 and f4 as the communication channel (S channel). Therefore, it is not possible to use the extension radio frequencies f7 and f8.
8 time slots T1 are assigned to mobile station H. Specifically, the mobile station G communicates using the communication channel S3 of the radio frequencies f3 and f4, and the mobile station H communicates with the radio frequency f.
Communication is performed using the communication channel S4 of 7 and f8. As described above, the state in which the time slot T1 of the radio frequencies f7 and f8 is allocated to the mobile station H is shown in FIG.
This is shown in (d).

In such a case, the time slots T2, the time slots T3 and the time slots T4 of the radio frequencies f7 and f8 are not used as communication channels (S channels) but are transmitted as empty channels. This is similar to the case of the wireless zone 1.

As described above, in the TDM / TDMA mobile radio network, even though there are empty slots of the radio frequencies f5 and f6 used in the radio zone 1, they cannot be used in the radio zone 2.

Similarly, even though there are empty slots of the radio frequencies f7 and f8 used in the radio zone 2, they cannot be used in the radio zone 1.

For this reason, the utilization efficiency of the radio channel is significantly reduced from the viewpoint of the entire mobile radio network.

Regarding the efficient use of frequencies, for example, Japanese Patent Application Laid-Open No. 4-28923 discloses an invention in which the number of time slots supported by each base station in each wireless zone is different for each base station. ing. In particular, it is described that the number of time slots is assigned according to the number of registered mobile stations.

Further, Japanese Patent Laid-Open No. 6-6855 discloses that when all channels served by a base station are used,
An invention is disclosed in which, when a new call request is made from a mobile station, a vacant channel of another adjacent base station can be used.

Further, Japanese Patent Laid-Open No. 6-6856 discloses an invention relating to a method of changing the allocation of channels allocated to each mobile station using a spare channel.

[0041]

As described above, in the conventional TDM / TDMA mobile radio network,
Despite the empty slots of the radio frequencies f5 and f6 used in the radio zone 1, these cannot be used in the radio zone 2 and the utilization efficiency of the radio channel is significantly lowered. is there.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless communication apparatus and method which enable efficient use of frequencies.

[0043]

The first aspect of the present invention is, in order to solve the above-mentioned problems, in a wireless communication apparatus based on a cellular system, the first base station in a first wireless zone served by the first base station First communication to a first mobile unit and second communication from the second base station to a second mobile unit in a second wireless zone that is adjacent to the first wireless zone and is under the control of a second base station And an assigning unit that assigns the same radio frequency, a communication channel of the radio frequency used by the first communication, and a communication channel of the radio frequency used by the second communication are different from each other. And channel setting means for setting.

Since the assigning means of the present invention assigns different channels of the same frequency in the first wireless zone and the second wireless zone to the respective wireless zones, efficient use of radio waves becomes possible.

In order to solve the above-mentioned problems, a second aspect of the present invention provides a wireless communication method based on the cellular system, comprising the first aspect.
A first communication from the first base station to a first mobile unit in a first wireless zone that the base station is in charge of, and a second wireless zone that is adjacent to the first wireless zone and is in charge of a second base station. The second communication between the second base station and the second mobile unit allocates the same radio frequency, a communication channel of the radio frequency used by the first communication, and the second communication A channel setting step of setting a communication channel so that the communication channel of the radio frequency to be used is different.

The present invention expresses the first aspect of the present invention as a method, and the operation thereof is substantially the same as that of the first aspect of the present invention.

In order to solve the above-mentioned problems, a third aspect of the present invention is the radio communication apparatus according to the first aspect of the present invention, wherein the first base station transmits radio waves only in a channel to which the first communication is assigned. The second base station includes output means for transmitting radio waves only in a channel to which the second communication is assigned.

Since the output means of the present invention emits radio waves only in the assigned channel and does not emit radio waves in other channels not used in that wireless zone, different channels are used in adjacent wireless zones. However, there is no interference.

In order to solve the above-mentioned problems, a fourth invention of the present invention is the radio communication method of the second invention, wherein the first mobile unit and the first base station are assigned the first communication. It is characterized by including an output step of transmitting a radio wave only in a channel, and an output step of transmitting a radio wave only in a channel to which the second base station and the second base station are assigned the second communication. .

The present invention expresses the above-mentioned third invention as a method, and its operation is also substantially the same as that of the third invention.

In order to solve the above problems, a fifth aspect of the present invention is the radio communication apparatus according to the first or third aspect of the present invention, wherein the channel setting means is a signal of the radio frequency in a time division multiplexing system. And a time slot allocating means for allocating the predetermined time slot of as the communication channel.

The time slot allocation means of the present invention is
Since the time slots in the time division multiplexing system are assigned as channels, it is possible to use different time slots in adjacent wireless zones.

In order to solve the above problems, a sixth aspect of the present invention is the radio communication method according to the second or fourth aspect of the present invention, wherein the channel setting step is performed in the signal of the radio frequency in the time division multiplexing system. A time slot allocating step of allocating a predetermined time slot of as the communication channel.

The present invention expresses the fifth aspect of the present invention as a method, and its action is substantially the same as that of the fifth aspect of the present invention.

In order to solve the above problems, a seventh invention of the present invention is the radio communication apparatus of the third or fifth invention, wherein the first base station is a time slot to which the first communication is allocated. In, including the output means with a guard time to start the output of the radio wave after a predetermined guard time has elapsed after the start of this time slot, and before the end of this time slot, to end the output of the radio wave by a predetermined guard time, The second base station starts outputting radio waves in a time slot to which the second communication is assigned after a predetermined guard time has elapsed after the start of this time slot, and before the end of this time slot, a predetermined time. It is characterized in that it includes an output means with a guard time that terminates the output of the radio wave in advance of the guard time.

The output means with guard time of the present invention, when outputting the radio wave of each time slot, transmits the radio wave with a certain guard time in order to prevent interference with other time slots. Therefore, even if the radio waves of the adjacent time slots are used in the adjacent radio zones, it is possible to prevent radio wave interference due to propagation delay of the radio waves.

In order to solve the above-mentioned problems, an eighth invention of the present invention is the radio communication method of the third or fifth invention, wherein said first base station is assigned a time slot to which said first communication is allocated. In the output step with a guard time that starts the output of the radio wave after a predetermined guard time has elapsed after the start of this time slot, and ends the output of the radio wave a predetermined guard time before the end of this time slot, The second base station starts outputting radio waves after a predetermined guard time has elapsed after the start of this time slot in the time slot to which the second communication is assigned, and before the end of this time slot, a predetermined guard An output step with a guard time that terminates the output of the radio wave ahead of the time, and is characterized by including.

The present invention expresses the above-mentioned seventh invention as a method, and its action is also substantially the same as that of the seventh invention.

[0059]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing a preferred embodiment of the present invention. As shown in the figure,
The cellular wireless communication network according to the present embodiment also
Similar to the conventional wireless communication network shown in FIG. 6, one control station 114, two first base stations 110 connected to this one control station 114, and a second base station 11 are connected.
And 2. Then, the first base station 110
Is in charge of the wireless zone 1, and the second base station 112
Is in charge of wireless zone 2.

A feature of this embodiment is that, as shown in FIG. 1, radio frequencies f5 and f for extension are used.
6 is configured to be simultaneously usable in both the wireless zone 1 and the adjacent wireless zone 2. In the wireless communication method adopting the conventional cellular system, different frequencies are used in adjacent wireless zones,
It was designed to not interfere with each other. But,
In the present embodiment, wireless zone 1 and wireless zone 2
Radio frequencies f5 and f6 commonly used in
Was shared in each zone by time-sharing between the zones.

Originally, the TDM system is a system in which one base station uses one radio frequency for a plurality of mobile stations in a time division manner to realize multiplex communication. In this embodiment, one radio frequency is shared by a plurality of radio zones by time division. as a result,
In the conventional wireless communication method, even if an empty channel is generated in a wireless frequency used in an adjacent wireless zone, the empty channel cannot be used, and a separate extension wireless frequency must be used. However, in the present embodiment, it is possible to use the radio frequency more efficiently.

In the present embodiment, the simultaneous sharing of one radio frequency in a plurality of radio zones is realized by transmitting no radio waves during the unused time slots, unlike the conventional case. . The fact that no radio wave is transmitted in an unused time slot will be described with reference to the explanatory diagram of FIG.

FIG. 2 is an explanatory diagram showing an example of the use situation of the radio frequency used in this embodiment. This figure is a diagram corresponding to FIG. 7 of a conventional wireless communication network. 1A and 1B, the basic radio frequencies f1 and f2 in the radio zones 1 and 2 are shown.
Of the time slots included in the radio frequency frame of the group of and the set of f3 and f4. This figure 2
7 (a) and 7 (b) are similar to FIGS. 7 (a) and 7 (b) of the above-mentioned conventional technique, and the multiplicity is "4" also in the present embodiment.
Further, as in the conventional case, one of the time slots included in one frame is used as a control channel (C channel).

A characteristic of this embodiment is that, as shown in FIGS. 2 (c) and 2 (d), a pair of f5 and f6 having the same frequency is set between the adjacent radio zones 1 and 2. Is being used. Since the same set of frequencies is used in the adjacent wireless zones 1 and 2, in each wireless zone 1 and 2, radio waves are emitted only in the time slots used and no radio waves are emitted in the unused time slots. Absent. In this way, in a certain wireless zone 1, neither the mobile station nor the base station emits radio waves during the time slots other than the time slots used in that wireless zone. Therefore, in the adjacent wireless zone 2, it is possible to perform communication using the unused time slot in the wireless zone 1.

In the text, such a communication system in this embodiment is called a random access system (RA system). Hereinafter, a specific channel allocation operation when the RA method is used will be described with reference to FIGS. 1 and 2.

A case where the number of multiplexed mobile radio networks of the RA / RA (RA: Random Access) system of this embodiment is set to 4 will be described.

In this embodiment, the control station 114
Grasps the radio frequency used in the first base station 110 or the second base station 112 and the time slot numbers (T1, T2, T3, T4) of the communication channel, and determines the first base station 110 and the second base station. In the station 112, supervisory control is performed so that the same time slot of the same frequency is not used at the same time.

The supervisory control is performed by the control station 114 using the line allocation table. An example of the line allocation table is shown in FIG.

As shown in FIG. 9, which radio zone is used for which mobile station (or control channel) is managed for each time slot of each frequency.

In this embodiment, similarly to the conventional example shown in FIG. 6, the first base station 110 has its own radio frequencies f1 and f2 and a radio frequency shared with the second base station 112. It is possible to transmit and receive certain radio frequencies f5 and f6.

The second base station 112 also has radio frequencies f3 and f unique to the second base station 112, as in the prior art.
4 and the first base station 110, it is possible to transmit and receive radio frequencies f5 and f6 which are common radio frequencies.

The time slot of each frequency is the same as that of the conventional technique (see FIGS. 6 and 7). That is, a frame formed by a set of radio frequencies f1 and f2 includes four time slots, and one time slot among them is a control channel (C channel). Also, the basic radio frequencies of the second radio zone, f3 and f4, also include four time slots, one of which is a control channel (C channel).

In this embodiment, the radio frequencies f5 and f6 are shared by the first radio zone and the second radio zone, and the frequencies f7 and f8 are not used.

The operation of assigning a predetermined channel in communication with the mobile station according to the present embodiment will be described below.

In the initial state of the mobile radio network of this embodiment, the first base station 110 and the second base station 112 are
Communication of any mobile station is not relayed.

From such an initial state, when there is a connection request from the mobile station A to the mobile station B in the radio zone 1, the first base station 110 uses the radio frequencies f1 and f2 as the communication channel (S channel). Time slot T2 and time slot T3 are allocated. That is, the mobile station A uses the communication channel S1 and the mobile station B uses the communication channel S1.
2 is used. This state is shown in FIG. FIG. 2 is a diagram similar to FIG. 7 for explaining the above conventional technique. In FIG. 2A, the time slot T2 (S1 as a communication channel) is used by the mobile station A, and the time slot T3 ( As a communication channel, S2) is mobile station B
Have been shown to be used.

Next, in the radio zone 2, the mobile station E
When there is a connection request from the mobile station F to the mobile station F, the second base station 112 uses the time slots T2 and T3 of the radio frequencies f3 and f4 as communication channels (S channels).
(S1 and S2 as communication channels) are assigned. This state is shown in FIG.

Then, when there is a connection request from the mobile station C to the mobile station D in the radio zone 1, the first base station 110 uses the radio frequencies f1 and f2 as communication channels (S channels). The time slot T4 and the time slot T1 of the radio frequencies f5 and f6 are allocated. This is because all the slots of the radio frequencies f1 and f2 have been used. This state is shown in FIG. As shown in FIG. 2C, the radio frequency f
A time slot T1 of 5 and f6 (S4 as a communication channel) is assigned to the mobile station D.

In this case, in the radio zone 2, the first call is made so as not to affect the call of the mobile station making a call (or making a call in the future) using the empty slots of the shared radio frequencies f5 and f6. Radio waves are transmitted from one base station 110 to the mobile station D in a burst.

The characteristic of this embodiment is that, as described above, in the shared radio frequencies f5 and f6,
Radio waves are transmitted only in used time slots, and radio waves are not transmitted in unused time slots. This state is shown in FIG. 2C. By comparing FIG. 2C with FIG. 7C, in the present embodiment, the time slots T1 (communication channel S4) of the radio frequencies f5 and f6 are shown. Radio waves are transmitted only in). As described above, in the present embodiment, since the radio waves are transmitted only in the used time slots, it is possible to use the unused time slots in the adjacent wireless zone 2.

Further, a characteristic of this embodiment is that a guard time is secured in each slot so as not to disturb adjacent slots. For example, when the time slot T1 is used in the wireless zone 1 and the time slot T2 is used in the wireless zone 2, since the propagation time of the radio wave differs depending on the distance between the base station and the mobile station, the mobile station in the wireless zone 2 Is time slot T2
When receiving the radio wave of, the radio wave of the time slot T1 in the wireless zone 1 may be mixed. This state is shown in FIG. As shown in FIG. 4A, the radio wave transmitted in the original time slot in the wireless zone 1 is delayed by a predetermined time while propagating to the wireless zone 2. Therefore, there is a possibility of interfering with an adjacent time slot in the wireless zone 2. Therefore, in the present embodiment, the radio waves transmitted in the time slots are provided with a predetermined guard time so that they do not interfere with the adjacent time slots. Note that FIG. 4B shows how the guard time is provided.

Now, from this state, this time the wireless zone 2
When there is a connection request from the mobile station G to the mobile station H, the second base station 112 uses the time slots T4 of the radio frequencies f3 and f4 as the communication channel (S channel).
And a time slot T2 of radio frequencies f5 and f6. Time slot T4 of radio frequencies f3 and f4
This is because it will not be enough. This state is shown in FIG.

In this case, as described above, the radio waves are transmitted in a burst so as not to interfere with the time slots T1 of the radio frequencies f5 and f6 during the call in the radio zone 1. Further, as described in FIG. 4 above, so as not to disturb adjacent slots,
A guard time is provided between each time slot.

A flowchart showing the operation of the control station 114 according to the first embodiment is shown in FIG.

As shown in the figure, first, in step S5-1, the control station 114 is in a state of waiting for a line connection request signal, in other words, a line allocation request signal.

Next, in step S5-2, the waiting channel allocation request signal is received by the control station 114 via the first base station 110 or the second base station 112.

Next, in step S5-3, the mobile station that has output the line allocation request signal and the base station that controls the wireless zone in which the mobile station exists are identified. Then, based on the grasp of the base station in step S5-3, it is checked in the next step S5-4 whether or not the request is via the first base station 110. As a result of the check, if the line assignment request is via the first base station 110, the process proceeds to step S5-5, and it is checked whether or not there is an empty channel on the frequency f1.

When it is determined in step S5-5 that there is an empty channel at the frequency f1, step S5.
The processing shifts to 5-6, and the line allocation using the idle channel is performed.

At step S5-7, the time slot T2 of the frequency f1 is newly added to the line allocation table.
Is used by a predetermined mobile station A (or B, C, D, etc.). The control station 114 is provided with a line allocation table storing information on whether or not the time slot is used for each frequency set in the format shown in FIG.

In this way, the lines are connected,
The process shifts to step S5-1 again to shift to the signal waiting state.

On the other hand, if there is no empty channel at the frequency f1 in the above step S5-5, step S5
The processing shifts to -8, and it is checked whether or not there is an empty channel at the frequency f5. As described above, this frequency f5
Is shared by the wireless zone 1 and the wireless zone 2, and as will be described later, regardless of how the current frequency f5 is used, even if it is a request from the second base station 112. , It is checked whether there is a free channel on the radio frequency f5.

As a result of this inspection, if there is an empty channel at the frequency f5, the line is assigned in step S5-9 by using that channel. And
The line allocation table is updated in step S5-10, and then the process proceeds to the signal waiting state in step S5-1.

In step S5-8, the frequency f5
If there is no free channel in the next step, the next step S5-1
The processing shifts to 1, and the line connection is disconnected as a call loss. Then, after that, the process returns to step S5-1. In FIG. 5, the use of the line is finished and the assignment is deleted from the line assignment table. Although the operation of the call termination process is not shown, this is an operation that is generally performed in the control device that performs the call origination process, and thus the description thereof is omitted.

When it is determined in step S5-4 that the connection request is from the second base station 112, the process proceeds to step S5-12, and it is checked whether or not there is an empty channel on the frequency f3. To be done. As a result of this check, if there is a free channel, in step S5-13,
Lines are allocated using the idle channels, and the line allocation table is updated in step S5-14. These operations are performed in step S above.
5-9 and step S5-10.

On the other hand, if there is no empty channel at the frequency f3 in step S5-12, step S5-8
The processing shifts to and it is checked whether or not there is an empty channel at the frequency f5. The process following this inspection has already been described above.

As described above, according to this embodiment, the empty time slots of the radio frequencies f5 and f6 used in the radio zone 1 can be used in the radio zone 2, so that the radio frequencies f7 and f8 can be used. The same function as described in the related art can be realized without using. That is, according to the present embodiment, it is possible to realize a communication system capable of improving the utilization efficiency of wireless channels.

Embodiment 2 In the above Embodiment 1, in each wireless zone,
Each had a fixed radio frequency. That is, the set of frequencies f1 and f2 is fixedly allocated in the wireless zone 1, and the set of frequencies f3 and f4 is fixedly allocated in the wireless zone 2. This is to keep the control channel at a constant frequency.

However, the control channel uses only one time slot of fixed frequency. Therefore,
The time slots other than the time slots used by the control channel can be shared by the wireless zone 1 and the wireless zone 2.

In this way, all frequencies are in the wireless zone 1
And wireless zone 2 are shared, wireless zone 1
And the control channel in wireless zone 2 should be in different time slots.
Therefore, in the second embodiment, the time slot 1 of the frequency f1 is used as the control channel of the wireless zone 1 and the time slot 2 is used as the control channel of the wireless zone 2. This state is shown in FIG. As shown in the figure, the time slots 3 and 4 of the frequencies f1 and f2 can be shared between the wireless zone 1 and the wireless zone 2 unlike the first embodiment. As a result, it is possible to further improve the effective use of radio frequencies.

The operation of the control station 114 of this embodiment is shown in FIG.
It will be described using the flowchart shown in FIG. In the second embodiment, all the communication channels (S channels) can be shared between the wireless zone 1 and the wireless zone 2, so that the effect of simplifying the search for the channel to be assigned is obtained. That is, all communication channels need only be searched in order.

First, in step S3-1, the control station 114 is in a state of waiting for a line connection request signal, in other words, a line line allocation request signal.

Next, in step S3-2, the waiting channel allocation request signal is received by the control station 114 via the first base station 110 or the second base station 112.

Next, in step S3-3, it is checked in the next step S3-4 whether the request is via the first base station.

Then, in step S3-4, it is checked whether or not there is an empty channel at the frequency f1. As a result of the inspection, if there is a free channel, the channel is assigned to the line connection request in step S3-7.

On the other hand, if there is no free channel in step S3-4, the process proceeds to step S3-5, and it is checked whether or not there is a free channel in the frequency f3. If there is a vacant channel as a result of the inspection,
Similarly, in step S3-7, the channel is assigned to the line connection request.

If there is no free channel in step S3-5, the frequency f5 is checked next. Hereafter, all frequencies that can be used are checked. As a result, when there is no empty channel in any frequency (step S3-6), step S3
In -9, it is treated as call loss and forced disconnection. Then, after that, the process returns to step S3-1. Note that in FIG. 3, the use of the line is finished and the assignment is deleted from the line assignment table. Although the operation of the call termination process is not shown, this is an operation that is generally performed in the control device that performs the call origination process, and thus the description thereof is omitted.

When the channels are assigned in step S3-7, the channel assignment table is updated in step S3-8. After the update of the channel table, the process moves to step S3-1 again to enter the standby state.

As described above, according to the second embodiment, the effective use of radio waves can be achieved and the operation of the control station can be simplified.

Third Embodiment In the first and second embodiments, the control channel (C channel) is fixed to the first slot of fixed frequencies f1 and f2, but the control channel (C channel) is set to a specific slot. It is also possible to place it in any slot without fixing it to. In this case, the mobile station can grasp the existing position of the control channel (C channel) by causing the mobile station to search for the control channel (C channel). Whether or not it is the control channel can be determined by the contents of the control channel (C channel).

Particularly, in order to secure the safety of the communication system, it is desirable that the control channel can be set in any time slot and any frequency.

Fourth Embodiment In the above first, second, and third embodiments, the shared frequency is set to f5 and f6 only (or f1 and f2 also), but the shared frequency is further increased due to an increase in communication traffic. It is also possible to increase. Even if the shared frequency is further increased, channels are assigned by the same control principle.

Embodiment 5 In the above Embodiments 1, 2, and 3, the mobile station A
Although only the mutual communication between the mobile station B and the mobile station E and the mobile station F has been described, it goes without saying that only one time slot may be used for a call between the base station and the mobile station. .

[0114]

As described above, according to the first and second aspects of the present invention, since the same frequency can be used in the adjacent wireless zones, the wireless communication device can efficiently use the wireless frequency.・ A method is obtained.

According to the third and fourth aspects of the present invention, since radio waves are emitted only in the allocated channel,
Even if the same frequency is used in adjacent wireless zones, interference does not occur, and more efficient use of radio waves becomes possible.

According to the fifth and sixth aspects of the present invention, since the time slots used in the adjacent radio zones are different, no interference occurs even if the same frequency is used, and more efficient radio waves are transmitted. It becomes available.

According to the seventh and eighth aspects of the present invention, since the guard time is provided in the signal of the radio wave output in each time slot, the radio communication device having high reliability capable of preventing interference due to the propagation delay time. And a method is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating an operation of a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a usage state of radio frequencies according to a preferred embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of the control station according to the preferred embodiment of the present invention.

FIG. 4 is an explanatory diagram of guard time in the preferred embodiment of the present invention.

FIG. 5 is a flowchart for explaining the operation of the control station according to the preferred embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating an operation of a conventional wireless communication device.

FIG. 7 is an explanatory diagram illustrating a usage state of a radio frequency of a conventional radio communication device.

FIG. 8 is a flowchart illustrating an operation of a control station in a conventional wireless communication device.

FIG. 9 is an explanatory diagram of a table for managing the usage status of radio waves.

FIG. 10 is an explanatory diagram of a case where all communication channels are shared.

[Explanation of symbols]

10 first base station, 12 second base station, 14 control station,
110 first base station, 112 second base station, 114 control station.

Claims (8)

[Claims] 1. A wireless communication apparatus based on a cellular system, wherein the first base station is in charge of the first wireless zone.
A first communication from the base station to the first mobile unit, and a communication from the second base station to the second mobile unit in a second wireless zone which is adjacent to the first wireless zone and which is handled by the second base station. Allocation means for allocating the same radio frequency to the second communication, a communication channel of the radio frequency used by the first communication, and a communication channel of the radio frequency used by the second communication, A wireless communication device comprising: a channel setting unit that sets a communication channel. 2. A wireless communication method based on a cellular system, wherein the first base station is in charge of the first wireless zone.
First communication from the base station to the first mobile unit, and communication from the second base station to the second mobile unit in a second wireless zone which is adjacent to the first wireless zone and is managed by the second base station. And an assignment step of assigning the same radio frequency, the communication channel of the radio frequency used by the first communication and the communication channel of the radio frequency used by the second communication are different from each other. And a channel setting step of setting a communication channel. 3. The wireless communication device according to claim 1, wherein the first base station includes an output unit that emits a radio wave only in a channel to which the first communication is assigned, and the second base station includes: A wireless communication device comprising: an output unit that emits a radio wave only in a channel to which the second communication is assigned. 4. The wireless communication method according to claim 2, wherein the first mobile unit and the first base station emit radio waves only in a channel to which the first communication is assigned, and the second step. The base station and the second base station include an output step of transmitting a radio wave only in a channel to which the second communication is assigned, and a radio communication method. 5. The wireless communication device according to claim 1, wherein the channel setting means allocates a predetermined time slot in the signal of the radio frequency in the time division multiplexing system as the communication channel. A wireless communication device comprising means. 6. The wireless communication method according to claim 2, wherein the channel setting step comprises setting a predetermined time slot in the signal of the radio frequency in the time division multiplexing system,
A wireless communication method comprising a time slot allocation step of allocating as the communication channel. 7. The wireless communication device according to claim 3, wherein the first base station is a time slot to which the first communication is assigned, after a predetermined guard time has elapsed after the start of this time slot. Start outputting radio waves,
Before the end of this time slot, the second base station includes an output unit with a guard time for ending the output of the radio wave ahead of a predetermined guard time, wherein the second base station is the time slot to which the second communication is assigned. After the prescribed guard time has elapsed after the start of
A radio communication device comprising an output unit with a guard time for ending the output of the radio wave before the end of this time slot by a predetermined guard time. 8. The wireless communication method according to claim 4 or 6, wherein the first base station has a predetermined guard time after the start of the time slot in the time slot to which the first communication is assigned. Start outputting radio waves,
Before the end of this time slot, an output step with a guard time for ending the output of the radio wave by a predetermined guard time ahead, and the second base station, in the time slot to which the second communication is assigned, After the start of the specified guard time, the output of radio waves will start,
A wireless communication device, comprising: an output step with a guard time, which ends the output of the radio wave before a predetermined guard time before the end of this time slot.