JP3014571B2 - Wireless communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless communication systems, and more particularly to bidirectional time division multiple access (TDM).
A) The present invention relates to a wireless communication system using the method.

[0002]

2. Description of the Related Art Conventionally, two-way radio communication has been performed by assigning different frequencies to the uplink and downlink directions.
By adopting the DMA (DMA) system, it has become possible to realize communication of a plurality of lines on the same frequency. Less than,
An example of the above-described conventional time division multiple access method will be described with reference to the drawings.

FIG. 13 is a diagram showing an example of a frame configuration in a conventional bidirectional time division multiple access system. FIG.
3, one transmission / reception cycle T in which uplink and downlink transmissions are performed once each is called a frame. Each frame is further composed of time-divided units called slots. In FIG. 13, S1 ↑ to S4 ↑ and S1 ↓ to S
4 ↓ represents each slot. Here, S1
{-S4} are slots for communication from the mobile station to the base station (in the upward direction), and S1 ↓ to S4 ↓ are slots for communication from the base station to the mobile station (in the downward direction). One line has a pair of uplink slots Sn # for each frame.
And a downlink slot Sn ↓ are assigned.

[0004] In the conventional bidirectional time division multiple access system as described above, the number of uplink and downlink slots allocated in one frame is always constant and fixed. In the example of FIG.
The number of lines that are divided into slots and can use the same frame simultaneously is four. In this way, the frame is divided into slots, and one line of communication includes one uplink slot and one downlink slot.
By using them one by one, bidirectional multiple access is realized between a base station and a plurality of mobile stations.

[0005]

However, in the conventional bidirectional time-division multiple access system as described above, since one line always uses one uplink and one downstream slot, the upstream and downstream slots are used. The number of slots and their ratio are always constant. Therefore, when the above-described conventional bidirectional time division multiple access method is applied to communication in which there is a difference between uplink and downlink traffic amounts, an unused portion occurs in a slot in a direction with a small traffic amount, and the unused portion is changed to another slot. Since the line cannot be used because of a busy line, there is a problem that communication efficiency is reduced.

[0006] Therefore, an object of the present invention is to provide a radio communication system capable of efficiently using slots in each frame and improving communication efficiency.

[0007]

The invention according to claim 1 is
The master station communicates with a plurality of slave stations in the downlink slot of each frame, and the master station communicates with the master station in a time-division multiple access scheme in which the slave stations communicate with the master station in the uplink slot of each frame. A radio communication system for transmitting and receiving signals to and from slave stations of an
A traffic monitoring means for monitoring the Ikku amount trough
Up and down troughs monitored by traffic volume monitoring means
The number of slots, which is set by the slot number ratio setting means for setting the uplink and downlink slot number ratios per predetermined number of frames , and the communication with each slave station according to the slot number ratio set by the slot number ratio setting means. Use predetermined
The number of downlink slot control means for controlling the number of slots down per number of frames, the number of slots ratio set by the slot number ratio setting means, pre to all slaves in the radio zone
The slave station controls the number of uplink slots per predetermined number of frames used for communication with the master station in accordance with the notified number-of-slots ratio. It has upstream slot number control means.

The invention according to claim 2 is such that communication is performed from the master station to a plurality of slave stations in the downlink slot of each frame, and communication is performed from the plurality of slave stations to the master station in the uplink slot of each frame. A wireless communication system for transmitting and receiving signals between a master station and a plurality of slave stations by a time division multiple access method, wherein the master station monitors uplink and downlink traffic volumes.
Traffic volume monitoring means and traffic volume monitoring means
From the upstream and downstream traffic volume ratio monitored by
A slot number allocating means for individually allocating the number of slots corresponding to a predetermined number of frames used for communication with each slave station to each slave station, and a number of slots allocated by the number of slot allocating means. Using a slot, the master station side communication control means for communicating with each slave station, and a notifying means for notifying the slave station of the number of slots assigned to each slave station by the slot number allocating means, wherein each slave station has its own station. A slave station communication control means for communicating with the master station using the notified number of slots.

[0009]

In the invention according to the first aspect , the master station is determined in advance (for example, based on the communication traffic with each slave station) .
When the ratio of the number of uplink slots to the number of downlink slots per frame is set, the predetermined number of downlink slots per frame used for communication with each slave station is controlled according to the set slot ratio. Also, the set slot number ratio is reported to all slave stations in the wireless zone. On the other hand, each slave station controls the number of uplink slots per predetermined number of frames used for communication with the master station according to the notified slot number ratio.

In the invention according to claim 2 , the master station comprises:
When the number of slots per predetermined number of frames used for communication with each slave station is individually assigned to each slave station (for example, based on the amount of communication with each slave station), the assigned number of slots is used. Communicate with each slave station. Also, the number of slots assigned to each slave station is notified to the slave station. On the other hand, each slave station communicates with the master station using the number of slots notified to itself.

[0011]

FIG. 1 is a system block diagram showing the configuration of a mobile radio telephone system according to a first embodiment of the present invention. The mobile radio telephone system shown in FIG. 1 is a base station (an example of a main station).
11 and 2 located in the wireless zone of the base station 11
Mobile stations (an example of slave stations) 12 and 13.
The base station 11 is connected to a communication network 14 via a predetermined transmission path. Time division multiple communication based on the principle of the present invention is performed between the base station 11 and the mobile stations 12 and 13.

FIG . 2 is a block diagram showing an internal configuration of base station 11 shown in FIG. The base station 11 includes a line control unit 21 that communicates with the communication network 14, an input unit 22 and an output unit 23 that are interfaces with a user, a communication control unit 24 that performs slot setting and communication control based on the slot setting,
Transmission unit 2 for performing communication with mobile stations 12 and 13
5, a receiving unit 26, an antenna 27, and a traffic amount monitoring unit 20 that monitors the amount of traffic to each mobile station based on the amount of communication in the transmitting unit 25 and the receiving unit 26. The communication control unit 24 includes a setting unit 28 for setting a slot, and a wireless control unit 29 for controlling the transmission unit 25 and the reception unit 26.

FIG . 3 is a block diagram showing the internal configuration of each mobile station shown in FIG. Each mobile station includes an input unit 31 and an output unit 32 serving as an interface with the user, a transmission unit 33, a reception unit 34, an antenna 35 for communicating with the base station 11, and setting of a slot from the base station 11. And a wireless control unit 36 for controlling the transmitting unit 33 and the receiving unit 34 in accordance with the following.

FIG . 4 is a frame configuration diagram for explaining a communication sequence in the first embodiment of the present invention.
In FIG. 4, the horizontal axis represents time. On this horizontal axis, slots obtained by time-dividing a communication frame whose period is T into eight are arranged. Here, the slots arranged on the upper side of the horizontal axis represent communication slots in the uplink direction (mobile station → base station), and the slots arranged on the lower side of the horizontal axis represent communication slots in the downlink direction (base station → mobile station). Represents a slot.

The setting unit 28 of the base station 11, based on the traffic monitoring data provided from the traffic amount monitoring unit 20 dynamically sets the slot structure of uplink and downlink radio control unit 29 of the local station slot configuration information And the wireless control unit 36 in the mobile stations 12 and 13 is notified. Base station 11
Of the mobile stations 12 and 13 receives the slot configuration information directly from the setting unit 28.
Receives the slot configuration information through the downlink broadcast slot S1 ↓ (timing a in FIG. 4). Each wireless control unit 2
Upon receiving the slot configuration information, the slots 9 and 36 change the uplink and downlink slot configurations from the timing b in FIG. 4 at the start of the next frame. For this purpose, each of the radio controllers 29 and 36 decodes the slot configuration code included in the slot configuration information and changes the ratio of the number of uplink and downlink slots (hereinafter, referred to as the slot number ratio). In the example of FIG. 4, the slot number ratio is 6: 2, and the slots T1 ↓ and T
2 ↓ is used for downlink communication, and slots T1 ↑ to T6 ↑ are used for uplink communication.

When the above-mentioned slot number ratio is changed to other than 4: 4, the lines in the direction with the smaller number are used once in every several frames by the lines using the slots in the direction with the larger number. For example, when the slot number ratio changes to 6: 2 at the timing b in FIG. 4, the downlink slots T2 ↓ excluding the broadcast slot T1 ↓ include six lines using the uplink slots T1 ↑ to T6 ↑ in order. Used once per frame. In addition, which line is in which frame in slot T2
The designation of whether to use ↓ is included as optional information in the slot configuration information in the notification slot S1 ↓ in FIG.

Furthermore, at timing b in FIG. 4, the broadcast slot T1 when a new slot configuration information of the following is reported in the radio control unit 29, 36 in ↓, the same manner as above new slot in the next frame The configuration is reset (timing c in FIG. 4).

FIG . 5 is a flowchart showing a slot configuration determining operation performed by setting section 28 of base station 11. Hereinafter, with reference to FIG. 5, how the setting unit 28 determines the slot configuration will be described. First, from the traffic monitoring unit 20 to the setting unit 28,
Information relating to the traffic amount for a certain period of time in the past in the up and down directions is input (step 51). Next, the setting unit 2
8 compares the current slot configuration with the provided traffic information (step 52). If the current slot number ratio does not match the ratio of the uplink traffic to the downlink traffic (hereinafter referred to as traffic volume ratio), the setting unit 28
It is checked whether an unused slot exists in the frame (step 53). If there is an unused slot in the frame, the setting unit 28 determines a new slot number ratio so that the slot number ratio approaches the traffic volume ratio (step 54). When the current slot number ratio and the traffic volume ratio match or when there is no unused slot in the frame, the setting unit 28 maintains the current state (step 5).
5).

[0019] Next, the setting unit 28, the slot configuration in which the newly determined, encoded according to the encoding table of FIG. 6 (step 56). This encoding table is set in the setting unit 28 in advance, and a slot configuration code is described corresponding to each combination of the number of uplink slots and the number of downlink slots. For example, when the slot number ratio is determined to be 6: 2, the slot configuration code is “3”. Next, the setting unit 28 creates slot configuration information including the slot configuration code obtained as a result of the encoding, directly notifies the radio control unit 29 of the base station 11, and stores and transmits the information in the notification slot S1 ↓. The wireless control unit 3 of the mobile stations 12 and 13 in the wireless zone via the unit 25
6 is notified (step 57).

FIG . 7 shows the setting unit 28 to the radio control unit 29 of the base station 11 and the radio control units 36 of the mobile stations 12 and 13.
FIG. 5 is a diagram showing an example of slot configuration information notified to the user.
As shown in FIG. 7, the slot configuration information includes a message type 61, a slot configuration code 62,
63 , a source address 64, a frame period 65,
Option information 66. In the message type 61, type information (for example, “0x80”) indicating a slot configuration information message is described. In the slot configuration code 62, the code encoded in step 56 of FIG. 5 is described. In the incoming call group address 63,
The common address of the mobile stations 12 and 13 receiving the slot configuration information is described. In this way, by describing a common address for each mobile station, slot configuration information is broadcast to all mobile stations in the wireless zone. The source address 64 describes the address of the base station 11. The slot configuration information is stored in the radio control unit 29 in the base station 11.
In the case where the notification is made directly, nothing is described in the destination group address 63 and the transmission source address 64. Frame cycle 65
Describes a period for notifying slot configuration information.
In this embodiment, since the slot configuration is adjusted for each frame, the frame period is described as one frame. The option information 66 describes the start time of changing the frame configuration and the slot use order. In the present embodiment, since the slot configuration is adjusted for each frame, the change start timing of the frame configuration is described as the next frame. In addition, the order of use of the slots is described as the order of the mobile stations 12 and 13.

The radio control section 29 of base station 11, FIG. 7
When the slot configuration information as described above is received immediately before the timing b in FIG. 4, for example, the slot configuration code 62 in the slot configuration information is decoded and the next one frame (the frames at timings b to c in FIG. 4) is decoded. The number of downlink slots and the number of uplink slots to be included therein are read. And
From the timing b in FIG. 4, the downlink slots T1 ↓ and T2 ↓ corresponding to the number of read downlink slots (two in FIG. 4).
Is transmitted to all the mobile stations in the wireless zone via the transmission unit 25. The downlink slot T1 ↓ is a broadcast slot for indicating the slot configuration of the next frame. Further, in the downlink slot T2 ↓, the mobile stations 12,
13 is stored.

On the other hand, the radio control unit 3 of the mobile station 12, 13
6 has already decoded the slot configuration code 62 in the slot configuration information stored in the broadcast slot S1 ↓ in FIG. 4 and has to be included in one frame (the frames at timings b to c in FIG. 4). Reads the number of slots and the number of uplink slots. Then, each of the radio control units 36 of the mobile stations 12 and 13 counts the number of downlink reception slots starting from the timing b in FIG. 4, and the number of reception slots is determined as the number of downlink slots in the above interpretation result (in the case of FIG. 4, At the time of coincidence with 2), the transmitter 33 is activated, and this time the base station 1
1 are transmitted for uplink slots T1 # to T6 #.

[0023] Thereafter, the base station 11 and the mobile station 12, 13
Repeats the same operation as above. Therefore, according to the first embodiment, the uplink and downlink slot configurations can be changed for each frame.

[0024] (Second Embodiment) FIG 8 is a frame configuration diagram for explaining a communication sequence in the second embodiment of the present invention. Hereinafter, a second embodiment of the present invention will be described with reference to FIG. Note that the hardware circuit configuration of the second embodiment is the same as that of the first embodiment (FIGS. 1 to 3). In the second embodiment, the same encoding table (see FIG. 6) and slot configuration information (see FIG. 7) as those in the first embodiment are used. Therefore, in the following description, the contents of FIG. 1 to FIG. 3, FIG. 6, and FIG.

As shown in FIG . 8, in the second embodiment, 1
The length of a frame is defined as T, and a two-frame period 2T is defined as one superframe. In the second embodiment, the setting and notification of the slot configuration and the configuration change control of the uplink and downlink slots are performed for each superframe. The length of the super frame is shown in FIG.
Is specified by the frame period 65 in the slot configuration information shown in FIG.

The setting unit 28 is, for example, a timing a of FIG.
Determines the slot configuration in the superframe 2T and encodes it. The algorithm for determining the slot configuration is the same as in the first embodiment (see FIG. 5). However, in the second embodiment, the length of the superframe is designated by setting the frame period 65 in FIG. 7 to two frames. The slot configuration information (see FIG. 7) created by the setting unit 28 is directly notified to the radio control unit 29 of the base station 11,
Further, the notification is made to the wireless control unit 36 of the mobile stations 12 and 13 using the notification slot S1 ↓. Each wireless control unit 29 and 3
6 changes the slot configuration of the next superframe (superframe starting from timing b in FIG. 8) according to the received slot configuration information. The change control of the slot configuration performed at this time is the same as in the first embodiment.

As described above, according to the second embodiment, the uplink and downlink slot configurations can be changed for each superframe having two frames as one unit. Therefore,
The slot configuration can be changed more flexibly. In particular, 1
This is effective when the number of mobile stations for one base station is large.

[0028] (Third Embodiment) The third embodiment is different from the first and second embodiments described above, so that on the basis of the Toraffiku amount of each line, to change the number of slots to be allocated to each line I have to. First,
With reference to FIG. 9, an operation of assigning the number of slots performed by setting section 28 of base station 11 will be described. Note that the hardware circuit configuration in the third embodiment is the same as that in the first embodiment (FIGS. 1 to 3). Therefore, in the following description, the contents of FIGS. 1 to 3 will be referred to as needed.

The setting unit 28 includes a traffic volume monitoring unit 10
When the past traffic information is input from (step 101), it is compared whether the traffic volume of each line is proportional to the number of slots allocated to each line (step 102). If the traffic volume of each line is not proportional to the number of slots allocated to each line, and, for example, the traffic volume of the mobile station 13 is overwhelmingly larger than that of the mobile station 12, the setting unit 28 determines that the unused slots It is checked whether or not the frame exists (step 103). If there is an unused slot in the frame, the setting unit 28 determines to allocate more uplink and downlink slot pairs to the line with the mobile station 13 having a large traffic amount (step 104). When the number of allocated slots is determined, the setting unit 28 encodes the result of the determination and obtains a slot allocation code (step 106). Next, the setting unit 28 creates slot allocation information including the slot allocation code, directly notifies the wireless control unit 29 of the base station 11, and also uses slots used for communication with the mobile station 13 (for example, FIG. 9 in the slot S1 ↓), and notifies the radio controller 36 of the mobile station 13 of the change of the used slot (step 107). If the traffic volume of each line is proportional to the number of slots allocated to each line, or if there is no unused slot in the frame, the setting unit 28 maintains the current state (step 105). .

FIG . 10 is a frame configuration diagram for explaining a communication sequence in the third embodiment. FIG.
In the frame at timings a and b, the base station 1
Up and down slots S1 ↓, S1１ are allocated to the line between the base station 11 and the mobile station 1.
Slot S3 ↓, S3 ↓
↑ is assigned. At timing a in FIG. 10, the setting unit 28 sets the unused slot S2 to the mobile station 13 having a large traffic amount, for example, according to the flowchart in FIG. 9.
When it is determined to assign ↓, S2 ↑, the corresponding setting unit 2
8 notifies the radio control unit 36 of the mobile station 13 of the slot assignment information including the determination result. Note that mobile station 1
There is no need to notify 2 if there is no change in the number of allocated slots. Upon receiving the slot assignment information, the radio controllers 29 and 36 change the number of assigned slots from timing b in FIG. 10 according to the slot assignment information and perform communication.

[0031] Here, it creates the setting unit 28, shown in FIG. 11 an example of a slot allocation information for notifying the radio control unit 29 and 36. As shown in FIG. 11, the slot assignment information includes a message type 91, a slot assignment code 92, a destination address 93, a source address 9
4 and option information 95. Message type 9
In 1, type information (for example, “0x81”) indicating a slot assignment change message is described.
The slot assignment code 92 stores a code obtained by setting a bit indicating the assigned slot. FIG. 12 shows an example of an encoding table used for this encoding. For example, a certain mobile station has a slot S1
When assigning ↓, S2 ↓, S1 ↑ and S2 ↑,
The value of the slot assignment code 92 is set to “0xCC” (see the n-th row in FIG. 12). As described above, according to the third embodiment, the number of slots assigned to each slave station can be made variable.

In the first and second embodiments,
The slot S1 ↓, which is one of the downlink slots, is used to broadcast the slot configuration information to the mobile station. However, as long as the mobile station can be broadcast, other slots may be used as the broadcast slot. You may. Furthermore, the slot configuration information may be broadcast using another control channel.

In the first and second embodiments,
When the slot configuration is designated, the radio controllers 29 and 36 change the slot configuration to the new configuration in the next frame or superframe, but the slot configuration may be changed at another time. For example, the change start time can be designated in the option information 66, thereby making the change start time of the slot configuration variable. Similarly, also in the third embodiment, the change start time is specified in the option information 95 in the same manner as described above, whereby the change start time of the slot configuration can be made variable.

Further , in the second embodiment, the length of the super frame is two frames. However, the length of the super frame is not limited to two frames, and may be any length of three frames or more.

In the third embodiment, the ratio of the number of up / down slots in a frame is fixed. However, by combining with the first and second embodiments, the ratio of the number of slots is made variable, May be assigned the optimal number of slots. In addition, priorities may be assigned to the communication lines, and a larger number of slots may be allocated to the communication lines with higher priority. Also, this priority is assigned to each mobile station 1
It may be possible to specify from 2 and 13. Note that the settings
The slot assignment information created by the
To the wireless control units 29 and 36
If you add frame period information that describes the frame period,
May be.

In the first to third embodiments, the setting unit 28 sets the slot configuration and the number of allocated slots based on the traffic information given from the traffic monitoring unit 20. May be queued each time an address is generated, and the slot configuration and assigned slot may be determined from the traffic of each address.

In each of the above embodiments, communication is performed between a base station and a plurality of mobile stations. However, the present invention is not limited to this, and can be widely applied to a main station (mobile type). The present invention can be applied to a communication system for performing communication between a plurality of slave stations (including both a mobile type and a stationary type) and a plurality of slave stations (including both a mobile type and a stationary type).

[0038]

According to the first aspect of the present invention, the ratio of the number of uplink and downlink slots for each frame is variably set based on the amount of communication with each slave station. Can be used efficiently. Thereby, it is possible to improve the communication efficiency of unidirectional communication such as file transfer, database access, remote log-in and the like, and broadcast such as bi-directional communication having different traffic volumes. Further, it is possible to cope with a change in the number of calls and the number of calls by changing the ratio of the number of slots, and there is an advantage that the number of terminals accommodated in the system can be increased. In addition,
Up / down slot number ratio is possible for each set number of frames.
Since it is set to change, every superframe
When the ratio of the number of slots for uplink and downlink is variably set,
The number of notifications or notifications to each slave station can be reduced
You. Therefore, the broadcast or notification slot is one super
One slot is required for each frame.
More slots for more efficient slot allocation
Can be achieved.

[0039] According to the second aspect of the invention, based on the amount of communication with each slave station, since the number of slots to be used for communication with each slave station has to allocate individually, several to communicate with one slave station By allocating slots and using them simultaneously, one slave station can use multiple lines,
As a result, the communication speed per slave station can be improved. Therefore, it is particularly effective when there is a difference in the traffic between the slave stations.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing a configuration of a mobile radio telephone system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a base station shown in FIG.

FIG. 3 is a block diagram showing an internal configuration of each slave station shown in FIG.

FIG. 4 is a frame configuration diagram for explaining a communication sequence in the first embodiment.

FIG. 5 is a flowchart illustrating a frame configuration setting operation performed by a setting unit according to the first embodiment.

FIG. 6 is a diagram illustrating an example of an encoding table used when a setting unit according to the first embodiment encodes a slot number ratio.

FIG. 7 is a diagram illustrating an example of slot configuration information created by a setting unit according to the first embodiment.

FIG. 8 is a frame configuration diagram illustrating a communication sequence according to a second embodiment of the present invention.

FIG. 9 is a flowchart illustrating a frame setting operation performed by a setting unit according to a third embodiment of the present invention .

FIG. 10 is a frame configuration diagram illustrating a communication sequence according to a third embodiment of the present invention.

FIG. 11 is a diagram illustrating an example of slot assignment information created by a setting unit according to the third embodiment.

FIG. 12 is a diagram illustrating an example of an encoding table used when a setting unit according to a third embodiment codes a slot allocation number.

FIG. 13 is a frame configuration diagram for explaining a communication sequence in a conventional wireless communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Base station 12, 13 ... Mobile station 14 ... Communication network 21 ... Line control part 22, 31 ... Input part 23, 32 ... Output part 24 ... Communication control part 25, 33 ... Transmission part 26, 34 ... Reception part 27, 35 antenna 28 setting unit 29 36 wireless control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B04B ⁷ /24-7/26 B04J 3/00 B04Q 7/00-7/38

Claims (2)

(57) [Claims] 1. A time division multiple access system in which a master station communicates with a plurality of slave stations in a downlink slot of each frame and a plurality of slave stations communicates with the master station in an uplink slot of each frame. A wireless communication system for transmitting and receiving signals between a master station and a plurality of slave stations, wherein the master station monitors traffic volumes of uplink and downlink.
Monitoring means, and upstream and downstream monitored by the traffic amount monitoring means.
Slot number ratio setting means for setting an uplink and downlink slot number ratio per a predetermined number of frames from the traffic amount ratio according to the number of frames, and a slot number ratio set by the slot number ratio setting means. Downlink slot number control means for controlling the number of downlink slots per predetermined number of frames used for communication with each of the slave stations, and a slot number ratio set by the slot number ratio setting means, within a wireless zone. Said predetermined to all slave stations of
Notifying means for notifying for each number of frames , wherein each of the slave stations controls the number of uplink slots per predetermined number of frames used for communication with the master station according to the notified slot number ratio. A wireless communication system comprising uplink slot number control means. 2. A time division multiple access system in which communication is performed from a master station to a plurality of slave stations in downlink slots of each frame, and communication is performed from a plurality of slave stations to the master station in uplink slots of each frame. A wireless communication system for transmitting and receiving signals between a master station and a plurality of slave stations, wherein the master station monitors traffic volumes of uplink and downlink.
Monitoring means, and upstream and downstream monitored by the traffic amount monitoring means.
From the traffic volume in advance,
A slot number allocating means for individually allocating the number of slots per a predetermined number of frames to each slave station, and a master station communicating with each of the slave stations using the number of slots allocated by the slot number allocating means. Side communication control means, and a notifying means for notifying the slave station of the number of slots allocated to each slave station by the slot allocating means for each of the predetermined number of frames , wherein each slave station notifies its own station. A wireless communication system comprising: a slave station side communication control means for communicating with the master station using the set number of slots.