JP3377935B2 - Polling method - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polling method, and more particularly to a polling method for packet transmission between a base station and a plurality of mobile stations in a mobile communication system.

In a mobile communication system, as shown in FIG. 13, each base station BS has a different radio zone, and each radio zone can accommodate a plurality of mobile stations MS1 to MSn. Then, the base station BS needs to constantly poll these mobile stations MS1 to MSn to register their respective positions.

[0002]

2. Description of the Related Art FIG. 14 shows a format of a polling instruction signal sent from a base station to a mobile station, and FIG.
The format of the polling response signal transmitted from the mobile station to the base station is shown, and FIG. 16 shows the format of the reception response signal after the polling response.

FIG. 17 shows a control sequence according to the above signal format, and FIG. 18 shows the same timing chart. In FIG. 18, the channel is divided into frames, and the frame is further divided into slots. The arrows indicate the polling instruction target and the polling response destination, and the # part indicated by □ indicates that the data is broadcast transmission data.

Each of the signal formats shown in FIGS. 14 to 16 has a preamble (1) for clock synchronization, a synchronization word (3) for frame synchronization, a color code (4) for distinguishing signals from interfering stations, When transmitting a polling response (polling instruction in the case of a base station), the mobile station (including the base station) divides it into packets of a length that can be transmitted in one slot, and transmits the packet. Is the first slot or the last slot, or the number of subsequent slots if it is not the last slot, and if it is the last slot, signal configuration information W (5) indicating the number of valid octets in the slot, polling including the mobile station number to be polled Polling instruction (6) sent from the base station when performing the polling, polling response (7) including the mobile station number sent from the mobile station as a response to the polling instruction, polling A reception response (8) indicating an affirmative response when the answer can be received by the base station without error, and a negative response when the answer is received incorrectly or the polling response cannot be received, and the signal configuration information W (5) And polling instructions
(6) (or polling response, reception response) and a data signal (2) including a redundant code.

Conventionally, as shown in FIGS. 17 and 18, the base station BS transmits a polling instruction # 1 for polling a specific mobile station such as the mobile station MS1 among the plurality of mobile stations MS1 to MSn. Then, the polling response # 2 transmitted from the mobile station MS1 which has received the polling instruction
Receive ~ 3 (response over 2 slots).

Then, a positive response or a negative response is received depending on whether or not the polling response can be received without error. Response # 4
The packet transmission is performed between the base station BS and the mobile station MS1 by repeating the transmission to the mobile station MS1 in a predetermined order.

This is the polling instruction # 5 to the reception response #.
The same applies to 9.

[0008]

Conventionally, in the transmission (# 5) of the polling instruction to the next (other) mobile station MS2, the reception of the polling response # 3 of the mobile station MS1 last time is completed, and the polling response # 3 is transmitted. Receive response whether or not it was received without error #
4 was transmitted to the mobile station MS1.

Therefore, when the mobile station MS1 transmits the polling response # 2, the time required for the processing inside the mobile station and the processing for the external device (processing times t11, t in FIGS. 17 and 18).
21) and the processing times t11 and t21 and the delay times t12 and t22 caused by the timing of the transmittable upstream channel.
Becomes longer, the subsequent polling is delayed by that amount, and the processing time and delay time of each mobile station are all added, which causes a problem that the polling cycle of the mobile stations MS1 to MSn is delayed. .

Therefore, according to the present invention, a wireless line is provided between a base station and a plurality of mobile stations, the base station transmits a polling instruction for polling a specific mobile station, and the mobile station which receives the polling instruction. In a polling method that repeats sending a polling response from the station to the base station,
The purpose is to perform polling at the minimum polling cycle without being affected by the previous polling operation.

[0011]

In order to achieve the above object, a polling method according to the present invention transmits a polling instruction from a base station to each mobile station sequentially at a fixed time interval.
To simultaneously transmits a collision control bit, the mobile station that has received the polling instruction, said the collision control bits from the polled instruction within an initial timer time only when the identification information indicates that the polling responsive , Sendable upstream
It is characterized by polling response at the timing of the channel . And the collision control bit is
The uplink channel type that can send polling responses from the station.
If it is continuing in imming, polling response is not possible
Indicates yes, otherwise pollable
It shows that it is Noh.

It should be noted that the collision of the mobile station that responded to the polling is normally received by the base station.
Data can be sent in the send slot of the next poll response only when the control bit indicates.

Further, when the collision control bit indicates that the transmission data of the mobile station which responded to the polling has not been normally received by the base station, the polling instruction is further received after a random delay time. The next polling response can be performed only when the collision control bit indicates that the polling response is possible within the initial timer time within a certain number of recycles.

Then, the base station includes in the collision control bit that the polling response from the mobile station has been normally received, and whether the received data is the final transmission slot. it can.

In the present invention, the base station transmits a polling instruction to a mobile station and, after a fixed time, transmits a polling instruction to the next mobile station. Also, the mobile station receives a polling instruction addressed to itself from the base station, and the collision control bit indicates that a polling response is possible. If the initial timer time has elapsed after receiving the polling instruction, Send a polling response.

When the polling response is not possible within the initial timer, the polling response to the received polling instruction is not transmitted, but the polling instruction addressed to the own station from the base station is received. The packet is transmitted when the collision control bit indicates that the polling response is possible.

If the collision control bit informs the transmitted packet that the base station has received the packet normally, subsequent packets are sequentially transmitted to inform that the packet has not been normally received. Or if it is informed that the packet is different from the packet sent from the base station,
If it is not the recycle, after a certain delay time, it is checked again whether or not the collision control bit is capable of polling response, and the polling response to the polling instruction is not performed regardless of the presence or absence of the following packet.

When the base station normally receives a packet from the mobile station on the uplink channel, the base station notifies the fact by the collision control bit and at the same time stops the notification that the polling response is possible. Then, when it is recognized that the reception of the series of packets from the mobile station is completed, the collision control bit notifies that the polling response can be restarted.

Further, when the base station normally receives the first transmission data of the polling response from the mobile station which has transmitted the polling instruction, it can transmit the polling instruction to the next mobile station. it can.

Further, the base station may notify the mobile station of the initial timer time, the random delay time, and the number of recycles.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A polling method according to the present invention will be described with reference to the following embodiments.

Embodiment (1) FIGS. 1 and 2 show the format examples (1) and (2) of the polling instruction signal transmitted from the base station to the mobile station, respectively, in the embodiment (1) of the polling method according to the present invention. ), FIG. 3 shows a format example of the polling response signal transmitted from the mobile station to the base station, FIG. 4 shows a control sequence, and FIG. 5 shows a timing chart. Further, FIG. 6 shows a transmission flow of the base station,
FIG. 12 shows a transmission flow of the mobile station.

The arrows in FIGS. 4 and 5 indicate the polling instruction target and the polling response destination, and the # part indicated by □ indicates that the transmission data and the collision control bit are broadcast.

First, referring to FIGS.
(1), sync word (3), color code (4), signal configuration information W (5), polling instruction (6), and polling response (7)
Is the same as the prior art shown in FIGS.

FIG. 1 shows a format example (1) of the polling instruction signal transmitted from the base station to the mobile station when the polling is performed as described above. The collision instruction bit (6) is included in the polling instruction (6). The point that 9) is included is different from the conventional technology.

The collision control bit (9) further indicates empty / block of the uplink channel to the base station (I (Idle) / B (Busy)) (10),
Indicates if the packet transmitted from the mobile station was received without error at the base station, or if it was received incorrectly or the packet transmitted from the mobile station could not be received (R
(Receive) / N (Non-receive)) (11), PE (Partial E) indicating the result of performing a certain process on the packet received by the base station.
cho) (12). As an example of PE (12),
There is a mobile station ID or a CRC code added to the upstream signal.

FIG. 2 shows a format example (2) of the polling instruction signal, but in this example, there is no polling instruction to be transmitted. For the data signal (2) when there is no polling instruction to be transmitted, only the collision control bit (9) is set. All the data areas other than the collision control bit (9) are set to "0" and a redundant code is added. And send it to the mobile station.

Next, the operation of the embodiment (1) of the present invention using the signal formats of FIGS. 1 to 3 will be described with reference to FIGS.

First, in FIGS. 4 to 6, when the polling instruction notification timer t _p (13) times out (step S1 in FIG. 6), the base station transmits a polling instruction to the corresponding mobile station. (S2), thereafter, every time the polling instruction notification timer t _p (13) times out, the polling instruction is sequentially transmitted to each mobile station.

For example, the base station BS, when the polling instruction notification timer t _p (13) times out after transmitting the polling instruction # 10 for polling the mobile station MS1,
Polling instruction # 1 for polling mobile station MS2
Sending 1

Upon receiving the polling instruction, each mobile station checks whether or not it is the target station (step S2 in FIG. 7).
1) If the subject station is the target, start the initial timer (T1) (at step S22), and set the collision control bit (9) of the collision control bit (9) notified in the slot in which the polling instruction was notified ("0" in this example) Check "I / B" (10) (S2 of the same)
3). If "I / B" is "I", the first polling response in the uplink channel immediately after "I" is broadcasted.
The slot is transmitted (at step S27).

If "I / B" is "B", the timer (T
Check whether 1) has timed out (S2
4) Collision control bit (12) after the next slot (S25)
Check "I / B" (at step S23), and set the initial timer T
If "I / B" becomes "I" in No. 1, the first slot of the polling response is transmitted on the uplink channel immediately after the notification of "I" (at step S27).

If the initial timer T1 does not become "I", the transmission fails (S26) and the transmission of the polling response to the received polling instruction is stopped.

In the examples shown in FIGS. 4 and 5, the mobile station MS1 that has received the polling instruction # 10 recognizes that the polling is addressed to itself, and is notified in the slot that received the polling instruction # 10. Check the "B / I" (10) of the collision control bit (9).

Since "B / I" = "I" is broadcast, the polling response # 1 2 which is the first slot of the polling response is transmitted to the base station BS. The signal configuration information W (5) of the polling response # 12 (see FIG. 3) includes
It is set that the polling response # 12 is the first slot and the number of subsequent slots is one slot.

The mobile station MS1 uses the polling instruction # 10.
Is received, and after the time t31 required for the internal processing of the mobile station and the processing of the external device and the delay time t32 resulting from the timing of the transmittable uplink channel, the polling response # 12
To send.

When the base station BS can normally receive the packet transmitted from the mobile station in the uplink channel (step S4 in FIG. 6), the base station BS sets the collision control bit (9) of the downlink channel immediately after the reception. The setting is performed as in the following setting 1 and transmitted to the mobile station.

[Setting 1] "R / N" (11) is set to R. The “PE” (12) is set to the received packet that has undergone certain processing (for example, the ID of the mobile station in question).
5). "I / B" (10), signal configuration information of received packet
Based on (5), it is checked whether or not there is a subsequent slot (S6 of the same), and if there is a slot, “B” is set (S6 of the same).
7) If there is no subsequent slot, set "I" (at step S8).

When the base station BS cannot normally receive the packet transmitted from the mobile station on the uplink channel (at step S4), the collision control bit (9) of the downlink channel immediately after the reception is received. The setting is performed as in the following setting 2 and is transmitted to the mobile station (at step S9).

[Setting 2] Set "R / N" (11) to "N". Set the "PE" (12) to "0". Set the "I / B" (10) to "I".

The mobile station which has transmitted the first slot of the polling response receives the "R / N" (11) and "PE" of the collision control bit (9) broadcast on the downlink channel immediately after the transmission of the first slot.
Check (12) (steps S28 and S2 in FIG. 7)
9). Then, there is a subsequent packet to be transmitted (see the same S3
0), when the notified collision control bit (9) is set as follows, the packet of the next slot is transmitted (at step S31).

When there is no subsequent packet to be transmitted and the notified collision control bit is set as in the following setting 3, the transmission is completed (at step S33).

[0043] [Configuration 3] "R / N" setting (11) setting is "R", "PE" (12), consistent with those own station subjected to certain processing in the transmission packets. Regardless of whether or not there is a subsequent packet to be transmitted, if the notified collision control bit setting does not satisfy the setting 3, unless N20 has recycled (S34 in the same), the random delay time T2 is set. After, the collision control bit (9) "I / B"
Is checked, and when it is set to "I", the first slot of the polling response is retransmitted (at step S27).

If "B" is set in step S23, the collision control bit (9) after the next slot
Check "I / B" of "I" in the initial timer T1
If so, the first slot of the polling response is retransmitted on the uplink channel immediately after the notification of "I" (S2 in the same figure).
7).

If the initial timer T1 does not become "I", the transmission fails (S26) and the transmission of the polling response to the received polling instruction is stopped.

When the base station BS can normally receive the subsequent packet transmitted from the mobile station on the uplink channel, the base station BS immediately after receiving the collision control bit on the downlink channel.
(9) is set as in setting 1 as described above (steps S7 and S8 in FIG. 6), and if it cannot be received normally, it is set as in setting 2 (step S9) and sent to the mobile station. (S10, S11).

The mobile station which has a succeeding packet and transmits the packet of the next slot (step S31 of FIG. 7) receives the "R / N" (9) of the collision control bit (9) broadcast on the downlink channel immediately after the transmission of the next slot. Check 11) (S3 of the same)
2). If there is a subsequent packet to be transmitted and the notified collision control bit (9) is set as in the next setting 4, the packet of the subsequent next slot is transmitted (at step S31).

[Setting 4] R / N (11) setting is R

When there is no subsequent packet to be transmitted and the notified collision control bit (9) is set as in setting 4, the transmission is completed (S33).

In addition, regardless of whether or not there is a subsequent packet to be transmitted, if the notified setting of the collision control bit (9) does not satisfy the above-mentioned setting 4, the transmission fails (S3).
As 6), transmission of the polling response to the received polling instruction is stopped.

Thus, in FIGS. 4 and 5, the base station B
S is a polling response # 12 transmitted from the mobile station MS1.
Is received normally, the collision control bit (9) of the downlink channel # 13 immediately after receiving the polling response # 12 is set to 1 and the mobile station MSn (n in this case is “3”) To inform. The polling instruction # 13 "I
/ B ”(10) is the signal configuration information W of the polling response # 12.
By (5), since it is notified that there is a subsequent slot, "B" is set. Also, the polling instruction # 13 “P
"E" (12) is set to the received polling response # 12 which has been subjected to a certain process.

Mobile station MS that sent polling response # 12
1 is the downlink channel # immediately after sending the polling response # 12
"R / N" (11) of the collision control bit (9) reported in 13,
Check "PE" (12). The mobile station MS1 transmits the polling response # 14, which is the packet of the next slot, because there is a subsequent packet and the setting of the collision control bit (9) broadcast on channel # 13 is set as in setting 3. To do.

Since the polling response # 14 transmitted from the mobile station MS1 has been normally received, the base station BS sets the collision control bit (9) of the downlink channel # 15 immediately after receiving the polling response # 14. , As in setting 1, mobile station M
Sn (n in this case is "4") is notified.

The "I / B" (10) of channel # 15 is
Since there is no subsequent slot notified by the signal configuration information W (5) of the polling response # 14, "I" is set. Further, the "PE" (12) of the channel # 15 is set to the received polling response # 14 which has been subjected to a certain process.

Mobile station MS that sent polling response # 14
1 is downlink channel # 15 immediately after polling response # 14 is transmitted.
In checking the "R / N" (11) of the notification by collision control bit (9). Since there is no subsequent packet and the setting of the collision control bit (9) broadcast on channel # 15 satisfies the setting 4, the mobile station MS1 polls the instruction # 10.
The polling response to is completed.

On the other hand, the mobile station MS2 that has received the polling instruction # 11 recognizes that the polling is addressed to itself,
Time t required for processing of internal and external devices of mobile station MS2
41 times later, downlink channel # 13 collision control bit (9)
Check "I / B".

Channel # 13 collision control bit (9) "I
The mobile station MS1 is transmitting a polling response to "/ B" (10), so "B" is broadcast. Mobile station MS2
Since "B" is broadcast by the collision control bit (9) of channel # 13, the upstream channel # 14 immediately after receiving channel # 13 does not transmit the polling response to the polling instruction # 11.

The mobile station MS2 checks the "I / B" (10) of the collision control bit (9) of the next slot # 15 of the channel # 13. Channel # 15 collision control bit (9) "I /
"B" (10) has been notified of "I" because the mobile station MS1 has finished transmitting the polling response.

Since the mobile station MS2 is informed of "I" by the collision control bit (9) of the channel # 15, it sends the polling response # 16 to the polling instruction # 11.

The operation of the base station BS and the mobile stations MS2 and MSn thereafter is the same as the operation when the mobile station MS1 transmits a polling response, and therefore its description is omitted.

The operation of this embodiment (1) can be summarized as follows. The base station transmits a polling instruction to the mobile station, and after a certain time, transmits a polling instruction to the next (other) mobile station. In addition, an "R / N" (acknowledgement) signal indicating that the packet from the mobile station is normally received on the uplink channel, a "PE" (echo) signal obtained by performing a certain process on the received packet, and an uplink "B /", which indicates that packet transmission from the mobile station is permitted on the channel
The "I" (block / empty) signal is broadcast on the downlink channel.

The mobile station divides the polling response into one or more packets, receives the polling instruction addressed to itself from the base station, and when the skyline signal "I" is not broadcast,
When the empty line signal "I" is notified in the initial timer (T1) which is the empty signal waiting timer, and when the empty line signal "I" is notified in the initial timer (T1) The packet is sent to the computer.

Within the initial timer (T1), the skyline signal "I"
Is not broadcast, the polling response to the received polling instruction is not transmitted, the polling instruction addressed to the own station is received from the base station, and if the skyline signal “I” is broadcast, the packet Is sent.

When the base station broadcasts an affirmative response signal "R" to the transmitted packet, subsequent packets are sequentially transmitted, and the base station transmits the negative response signal to the transmitted packet. "N" is reported, or
When an echo signal “PE” different from the packet transmitted from the base station is notified to the transmitted packet,
If the recycling (retry) is not over, the empty line signal “I” is checked after an arbitrary delay time (after the lapse of random delay time T2).

When the mobile station receives a negative response "N" from the base station while sequentially transmitting the subsequent packets, the mobile station responds to the polling response to the polling instruction regardless of the presence or absence of the subsequent packets. Packet is not transmitted.

When the base station normally receives the packet from the mobile station on the uplink channel, it sends an acknowledgment signal "R" and an echo signal for the packet and at the same time sends the skyline signal "I". When it stops and recognizes that the reception of a series of packets from the mobile station is completed, the skyline signal “I” is notified.

Embodiment (2) FIG. 8 is a control sequence of embodiment (2) of the polling method according to the present invention, FIG. 9 is its timing chart, and FIG. 10 is a transmission flow of the base station. Note that this example
As the signal format in (2), those shown in FIGS. 1 to 3 may be used. Moreover, FIG. 7 can be used for the transmission flow of the mobile station.

In the above embodiment (1), the polling instruction transmitted from the base station BS to the mobile stations MS1 to MSn is transmitted at regular intervals by the polling instruction notification timer t _p (13). However, in this embodiment (2), FIGS.
As shown in, for example, when the first slot of the polling response # 12 to the polling instruction # 10 is received (step S12 in FIG. 10), the timer t _p1 (17) (see FIGS. 8 and 9)
Stop (step S13) and send a polling instruction # 13 to the next mobile station, mobile station MS2 (step S13).
14).

On the other hand, the polling instruction notification timer t _p1 (17)
If the first slot of the polling response is not received (S12 in the same step), the timer t _p1 (17) is started (S15 in the same step).
15), and sends the polling instruction # 21 to the next mobile station (at the same S
2) may be performed.

The other points are the same as in Example (1).

Embodiment (3) FIG. 11 shows the format of the polling signal transmitted from the base station to the mobile station in the embodiment (3) of the polling method according to the present invention. Note that the signal formats of FIGS. 2 and 3 can be used also in this embodiment (3), the control sequence is shown in FIGS. 4 and 8, and the timing chart is shown in FIG. The transmission flow may use FIGS. 6 and 10, and the transmission flow of the mobile station may use FIG. 7.

In the above embodiments (1) and (2), the initial timer T1 random delay timer T2 and the number of retransmissions N20 used in the mobile station use fixed values inside the mobile station. Bits (18) set in the polling instruction bit (6) in the signal format shown in (1) may be used to notify the mobile station of an arbitrary value for these bits.

FIG. 12 shows numerical examples of these notification values, each of which is composed of 8 bits and has 256 bits.
It can be set according to the street.

[0074]

As described above, according to the polling method of the present invention, the base station transmits the collision control bit simultaneously with the polling instruction to the mobile station at a constant time interval, and receives the polling instruction. The mobile station is configured to respond to polling only when the collision control bit indicates that polling response is possible within the initial timer time after receiving the polling instruction. Even if the delay time increases, the polling cycle time can be minimized, and data transmission between the base station and the mobile station can be efficiently performed.

[Brief description of drawings]

FIG. 1 is an embodiment (1) of a polling method according to the present invention,
It is the figure which showed the polling instruction | indication signal format example (1) in (2).

FIG. 2 is an embodiment (1) of a polling method according to the present invention.
It is the figure which showed the polling instruction | indication signal format example (2) in (3).

FIG. 3 is an embodiment (1) of a polling method according to the present invention.
It is the figure which showed the polling response signal format example in (3).

FIG. 4 is an embodiment (1) of a polling method according to the present invention,
It is a figure showing the control sequence of (3).

FIG. 5 is a diagram showing an operation timing chart of the embodiment (1) of the polling method according to the present invention.

FIG. 6 is an embodiment (1) of a polling method according to the present invention,
It is a figure which showed the base station transmission flow of (3).

FIG. 7 is an embodiment (1) of a polling method according to the present invention.
It is a figure showing the mobile station transmission flow of (3).

FIG. 8 is an embodiment (2) of a polling method according to the present invention,
It is a figure showing the control sequence of (3).

FIG. 9 is an embodiment (2) of a polling method according to the present invention,
It is the figure which showed the operation timing chart of (3).

FIG. 10 is a diagram showing a base station transmission flow of embodiments (2) and (3) of the polling method according to the present invention.

FIG. 11 is an embodiment (3) of a polling method according to the present invention.
5 is a diagram showing an example of a polling instruction signal format in FIG.

FIG. 12 is an embodiment (3) of the polling method according to the present invention.
It is a figure showing an example of a numerical value in.

FIG. 13 is a diagram showing a general configuration example of a mobile communication system.

FIG. 14 is a diagram showing an example of a polling instruction signal format in a conventional technique.

FIG. 15 is a diagram showing an example of a polling response signal format in the prior art.

FIG. 16 is a diagram showing an example of a reception response signal format in the prior art.

FIG. 17 is a diagram showing an example of a control sequence of a conventional technique.

FIG. 18 is a diagram showing an operation timing chart of a conventional technique.

[Explanation of symbols]

BS base station MS1 to MSn mobile stations In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 H04Q ⁷ /00-7/38 H04L 12/40

Claims (6)

(57) [Claims] 1. A wireless circuit is provided between a base station and a plurality of mobile stations, the base station transmits a polling instruction for polling a specific mobile station, and the mobile station receiving the polling instruction can transmit. In a polling method in which a polling response is repeatedly transmitted to the base station at different uplink channel timings, the base station sequentially transmits a polling instruction to each mobile station at fixed time intervals, and at the same time, a mobile station sends a polling instruction. If the polling response is continuing at the timing of the upstream channel, it indicates that the polling response is impossible,
Otherwise, a collision control bit indicating that polling response is possible is sent to all mobile stations by the polling instruction.
The mobile station that broadcasts at the same timing as shown, and receives the polling instruction, only when the collision control bit indicates that a polling response is possible within the initial timer time after receiving the polling instruction, A polling method characterized by performing a polling response at the timing of an upstream channel. 2. The transmission slot of the next polling response according to claim 1, only when the collision control bit indicates that the transmission data of the mobile station that has responded to the polling has been normally received by the base station. A polling method characterized by transmitting data by. 3. The polling control bit according to claim 1, wherein when the collision control bit indicates that the transmission data of the mobile station responding to the polling has not been normally received by the base station, the polling is further performed after a random delay time. A polling method characterized in that the next polling response is performed only when the collision control bit indicates that polling response is possible within a fixed number of recycles within the initial timer time after receiving the instruction. 4. The base station according to claim 1, when the base station normally receives the first transmission data of the polling response from the mobile station that has transmitted the polling instruction, issues a polling instruction to the next mobile station. A polling method characterized by transmitting. 5. The base station according to claim 3, wherein the base station has the initial timer time, the random delay time,
And a polling method characterized in that the base station notifies the mobile station of the number of times of recycling. 6. The method of claim 1, wherein the base station is in the collision control bit, it has normally received the polling response from the mobile station, and whether or not the received data is the last transmission slot The polling method is characterized by including.