JPH08213990A - Method and device for radio packet communication - Google Patents

Abstract

PURPOSE: To cooperatively operate the idle line control access and the split tree algorithm by inhibiting transmission of newly occurring incoming packets in the case of collision of incoming packets on a packet channel and permitting retransmission of only the packets which have collided with each other. CONSTITUTION: If incoming packets simultaneously transmitted from two or more of mobile stations 2 collide with each other on the packet channel, a base station 1 reports a collision resolution signal besides an inhibition signal or an idle line signal. When the collision resolution signal is reported, each mobile station 2 inhibits transmission of up packets, which newly occur after the occurrence time of the packet which collide, and retransmits this packet. Thus, the idle line control is used or the idle line control and the reservation control are combined to efficiently perform the random access in the case of the absence of collition, and packets are efficiently retransmitted based on the split tree algorithm in the case of the occurrence of collision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for wireless packet communication. In particular, it relates to random access of wireless packets.

[0002]

2. Description of the Related Art ICMA (Idle-signal casting) used in current middle-aged and small-sized car telephones is used as a skyline control access method for controlling random access of wireless packets.
multiple access) and ICMA-DR (ICMA with
data slot reservation) is known.

[0003] ICMA is a method of informing the use status of the uplink control channel by the downlink control channel. In the idle state, an air line signal is issued to allow access of each mobile station, and when in use, it is prohibited. By notifying the signal and prohibiting the access of other mobile stations, signal disappearance due to collision of uplink signals from the mobile station to the base station is reduced. However, since there is a delay between the base station detecting the signal of the upstream channel and changing the skyline signal to the prohibition signal, the collision cannot be completely eliminated.

The ICMA-DR is a system in which reservation control is incorporated into the ICMA system in order to further improve the efficiency of the ICMA. A mobile station transmitting a message to a base station first transmits a short reservation signal on an uplink channel before transmitting the message. When the base station receives the reservation signal, it changes the downlink skyline signal into a prohibition signal. The mobile station that has transmitted the reservation signal transmits a message signal via the uplink control channel after confirming that the signal from the base station has changed from a blank signal to a prohibition signal. When the transfer of the message is completed, the base station changes the prohibition signal to a blank signal again. As a result, even if a collision occurs, only the short reservation signal disappears, so that the efficiency of the channel is improved.

FIG. 12 shows ICMA-DR with 3ch TDMA.
An example of operation when used in an FDD (3-channel time division two-wave duplex method) wireless transmission system is shown. 3ch TDMA
ICMA when used in FDD wireless transmission systems
-DR is particularly called "intermittent slot line control type".
In this case, the skyline signal and the prohibition signal broadcast by the base station are set in slot units, and the mobile station performing message transfer can transmit the reservation signal in the corresponding slot at the time of the skyline signal. When the reservation signal can be correctly received, the base station starts notification of a prohibition signal (a permission signal for the mobile station that has transmitted the reservation signal) from the subsequent slot. Further, the mobile station transmits the message as data in slot units in response to the change of the skyline signal to the permission signal. The figure shows an example of transmitting data in three slots. Focusing only on the reservation signal in this method, the algorithm is similar to that of the slotted ALOHA, and when a plurality of reservation signals collide, each mobile station retransmits the reservation signal after a random waiting time.

As an operation when a random access signal collides, there is a method of using a split tree algorithm in addition to a method of retransmitting after a random waiting time such as ALOHA. The split tree algorithm temporarily prohibits the transmission of new packets after a collision occurs, and allows only mobile stations that have collided to retransmit. This period is called a conflict resolution period. Within this period, the set of colliding mobile stations is divided into subsets, and mobile stations of any one of the subsets are permitted to retransmit. If the conflict is still unresolved,
Further division is performed.

FIG. 13 shows the outline of the operation of the split tree algorithm. Here, the case where the mobile stations A, B, and C collide is shown. After the collision occurs, the collision mobile station randomly selects "1" or "0" and is separated into a set "1" and a set "0", respectively. Here, first, retransmission is permitted for the set "1", but since there are two mobile stations A and C in this set, a collision occurs again. So mobile station A
Further, C and C randomly select "1" or "0" and repeat the separation. As a result, the collision is resolved when the mobile stations A and C both select “1” as shown in the figure, when they are separated into the sets “11” and “10”. Since it exists, the collision cannot be resolved, and the separation is performed again. As a result, when the both are separated into the set “111” and the set “110”, the retransmission for each set is successful. Next, the retransmission permission is given to the set 10. However, since there is no mobile station belonging to this set, there is no transmission, and the transmission permission is given to the set 0. If the mobile station B transmits successfully here, the collision resolution period ends.

By using the split tree algorithm when a random access signal collides, it is possible to maintain stability and achieve high throughput with relatively simple control.

[0009]

The skyline control access is very effective for improving the efficiency of random access of wireless packets. On the other hand, it is possible to improve the throughput and delay characteristics by using the split tree algorithm as the control at the time of collision. Therefore, an object of the present invention is to realize an access method combining both as a random access method for wireless packets.

By the way, in the skyline control access, access of a subordinate mobile station is controlled by always reporting a prohibition signal or a skyline signal by a downlink signal, whereas in the split tree algorithm, a collision resolution period The access of the mobile station is controlled by setting and notifying the retransmission control signal. Therefore, in order to combine the two, it is necessary that the skyline control access and the split tree algorithm operate cooperatively.

That is, it is an object of the present invention to provide a wireless packet communication method and apparatus capable of cooperatively operating a skyline control access and a split tree algorithm.

[0012]

A first aspect of the present invention is a wireless packet communication method, in which wireless packet communication is performed between a base station and a plurality of mobile stations under its control using a common packet channel. Therefore, the base station notifies the mobile station of a forbidden signal indicating that the packet channel is in use or a skyline signal indicating that the packet channel is in an idle state. In a wireless packet communication method for starting transmission of an uplink packet to a base station, when uplink packets transmitted simultaneously from two or more mobile stations collide with each other on a packet channel, the base station collides instead of a prohibition signal or a skyline signal. It sends a resolution signal, prohibits the transmission of uplink packets newly generated after the time of occurrence of the packet in which the collision occurred, and retransmits only the packet in which the collision occurred. Characterized in that it allowed.

When an uplink packet collision occurs, the mobile station that has transmitted the packet generates a random number in a predetermined range, and the base station sets the mobile stations to a plurality of random numbers corresponding to the value of the random number. It is divided into subsets, and a retransmission control signal for granting retransmission permission to each of the subsets in turn is transmitted at the same time as the collision resolution signal. When a further subdivision is impossible, it sends a retransmission control signal corresponding to the subdivided subset of the Is recreated and this operation is repeated for all subsets until no collisions are detected.

When the sequential transmission of the retransmission control signal from the base station to the subset is completed, and no collision is detected in the retransmission from each subset, the base station detects the packet in which the collision has occurred. A signal from any mobile station is transmitted even if a retransmission control signal that permits retransmission is transmitted to all mobile stations that have transmitted the packet and transmission of the packet has not been completed and this retransmission control signal is transmitted. If it is not received, it is preferable to end the series of collision resolution control and restart the notification of the sky line signal.

When transmitting a packet, the mobile station transmits a reservation signal to the base station prior to the transmission of the packet, and when the reservation signal is normally received, the base station transmits the packet to the mobile station. It is better to give permission to send.

A second aspect of the present invention is an apparatus for carrying out the above method, comprising a base station and a plurality of mobile stations for performing wireless packet communication using a common packet channel, and the base station uses the packet channel. The mobile station includes means for notifying the mobile station of a prohibition signal indicating that it is in the middle or a skyline signal indicating that the mobile station is in an empty state, and each of the mobile stations sends an uplink packet to the base station when the skyline signal is notified. In a wireless packet communication device including means for starting transmission of a packet, the base station, in the case where uplink packets simultaneously transmitted from two or more mobile stations collide with each other in a packet channel, resolves a collision instead of a prohibition signal or a skyline signal. Each of the mobile stations includes means for notifying a signal, and when a collision resolution signal is notified, each mobile station newly generates an uplink power after the time when the packet in which the collision occurred is generated. Characterized in that prohibits the transmission of Tsu bets including means for retransmitting the occurred packet collision.

Each mobile station includes means for generating a random number in a predetermined range when the packet transmitted by the mobile station causes a collision, and the base station corresponds to the value of the random number generated by each mobile station. These mobile stations are divided into a plurality of subsets, and means for simultaneously transmitting a retransmission control signal for granting retransmission permission to each of the subsets at the same time as a collision resolution signal, and a predetermined number of times If the collision cannot be resolved even after the division, it is preferable to include means for instructing the mobile stations belonging to the subset to regenerate the random number.

The base station completes the sequential transmission of the retransmission control signal for the subset, and when no collision is detected in the retransmission from each subset, the mobile station that has transmitted the packet in which the collision has occurred And a means for transmitting a retransmission control signal that permits retransmission to all mobile stations that have not completed transmission of the packet, and a signal from any mobile station that receives this retransmission control signal. If not, a means for ending a series of collision resolution control and restarting the notification of the sky line signal may be included.

The mobile station includes means for transmitting a reservation signal to the base station before transmitting the packet when the packet is transmitted, and the base station transmits the reservation signal when the reservation signal is normally received. Means may be included for authorizing the station to send the packet.

[0020]

The collision resolution signal transmitted exclusively to the skyline / prohibition signal in the skyline control access is set, and the skyline control and the split tree algorithm are switched when the signal collision occurs. As a result, when there is no collision, skyline control or high-efficiency random access that combines skyline control and reservation control can be performed, and when a collision occurs, retransmission can be efficiently performed based on a split tree algorithm. .

In the conventional split tree algorithm, a set is split due to collision, and transmission permission is given to each set. Therefore, as the number of colliding mobile stations increases, the number of subsets sufficient to separate them also increases, and the amount of signal representing that subset in the retransmission control signal increases. Specifically, if the number of subsets is n and the number of bits required to represent it is k,
There is a relationship of k = log ₂ n. On the other hand, the number of bits of the control signal in the actual system is finite, and it is desirable that the control be realized with as few bits as possible.

Therefore, a random number is generated in the mobile station that has transmitted the collision packet within a predetermined range, the mobile station is divided into subsets based on the value, and retransmission permission is given to each, but repeated collisions occur. If the subset cannot be further subdivided, a mobile station belonging to the subset is instructed to regenerate a random number, the subset is reformed, and the split tree algorithm is repeated. This allows
Retransmission control signals for the divided subsets can be expressed with limited information, and yet it is possible to realize almost the same functions as conventional ones.

Fading, shadowing, and free space loss are characteristics of radio wave propagation to be considered in mobile radio. Due to these factors, the received power of the signal from each mobile station in the base station becomes random, and even if there is a large difference in received power even between the signals that have collided, a strong signal cancels a weak signal, The base station may judge as if there was no collision. This is called the capture effect. Even if there is no collision, the signal may not be received due to the drop of the received signal due to fading.
On the other hand, in the split tree algorithm, if there is no signal collision, transmission is not permitted for that partial signal any more.Therefore, a signal canceled by the capture effect or fading during the collision resolution period has its collision resolution period It will be retransmitted again after the end, which is one of the causes for reducing the effect of the split tree algorithm.

Therefore, after the sequential transmission of the retransmission control signal for the subset generated in the split tree algorithm is completed, a special retransmission enable signal that does not specify the subset is transmitted, and a packet canceled by the capture effect or fading is transmitted. After confirming that there is none, the conflict resolution period ends. As a result, even if the signal disappears due to the capture effect or fading, the probability of retransmission can be increased during the collision resolution period.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of a wireless packet communication device according to an embodiment of the present invention. The apparatus of this embodiment includes a base station 1 and a plurality of mobile stations 2 that perform wireless packet communication using a common packet channel. The base station 1 uses a prohibition signal indicating that the packet channel is in use or an idle state. A plurality of mobile stations 2 are informed of a skyline signal indicating that there is a mobile station 2, and each of the plurality of mobile stations 2 can start transmission of an upstream packet to the base station 1 when the skyline signal is informed. . The base station 1 also has two of the mobile stations 2.
From the above, when the uplink packets transmitted at the same time collide with each other in the packet channel, the collision resolution signal is broadcast instead of the prohibition signal or the skyline signal, and each mobile station 2 receives the collision resolution signal when the collision resolution signal is broadcast. It is possible to prohibit the transmission of an upstream packet newly generated after the generation time of the collision packet and retransmit the collision packet.

FIG. 2 shows an operation example of the apparatus of this embodiment by a downlink packet from the base station to the mobile station and an uplink packet from the mobile station to the base station. The wireless channel is a time division two-wave duplex system.

In this operation, first, the mobile station which is going to transfer the packet confirms that the skyline signal is broadcast in the immediately preceding downlink slot, and then transmits the reservation signal on the uplink channel. When the base station normally receives the reservation signal without collision, the base station broadcasts the prohibition signal in the subsequent downlink slot.
After confirming that the skyline signal has been converted into a prohibition signal, the mobile station transmits data to the subsequent slots, and skyline control access is performed by combining reservation control.

When the reservation signals collide with each other, the base station broadcasts a collision resolution signal including a retransmission control signal. The mobile station which has detected the collision by the collision resolution signal internally generates a 3-bit random number. The retransmission control signal designates the mobile station that permits the retransmission of the reservation signal in the next uplink slot. Table 1 shows the relationship between the retransmission permission condition and the random number inside the mobile station.

[0029]

[Table 1] Here, the retransmission control signal is composed of 4 bits. For example, when the retransmission control signal is "0101", the retransmission permission condition is that the last two digits of the 3-bit random number be "01". Further, when the retransmission control signal is “0010”, the retransmission of the reservation signal is permitted regardless of the value of the random number. When the retransmission control signal is "0011", the mobile station regenerates an internal random number.

Now, the example shown in FIG. 2 will be described. In this example, it is assumed that two reservation signals collide and each mobile station generates a random number of "100" and "110", respectively. The base station transmits a retransmission control signal of "000" in response to the first collision, and permits the mobile station whose last digit of the random number is "0" to be retransmitted. However, since this condition applies to both mobile stations that have collided, the collision of reservation signals continues to occur. Therefore, the base station further divides the set and transmits a retransmission control signal of "0100", and as a result, only the mobile station that has generated a random number of "100" can transmit the reservation signal, which is similar to the skyline control. Send data in steps. Furthermore, the base station transmits a retransmission control signal of "0110" and accepts a reservation signal and data from the mobile station that generated the random number of "110". At this point, the base station determines that the mobile station that has collided has completed the retransmission of the mobile station whose last digit of the random number is "0", and then generated the random number of which the last digit is "1". Give the mobile station permission to resend "000
The retransmission control signal of "1" is transmitted. Since there is no mobile station that meets this condition, the base station tentatively determines that the retransmitting of the colliding mobile station has been completed. Finally, a retransmission control signal of "0010" that permits the retransmission of the reservation signal is transmitted regardless of the value of the random number, confirms that there is no signal from the mobile station, and returns to normal skyline control.

FIG. 3 shows the operation of the split tree algorithm at this time. “0” by the first division, “00”, “10” by the second division, and “1” by the first division are respectively the collision resolution signals “000”,
It corresponds to “0100”, “0110”, and “0001”.

FIG. 4 is a diagram for explaining the operation when the random numbers match and is reset, and FIGS. 5 and 6 show the operation of the separation tree algorithm before the random number reset and after the random number reset, respectively. Here, after the reservation signals from the two mobile stations have collided, each mobile station has the same “101”.
It is assumed that a random number of is generated. The base station uses “0”, “1”, “0” in the split tree algorithm shown in FIG.
Retransmission permission is given in the order of "1", "001", "101", "11". The retransmission control signals at this time are “0000”, “0001”, “0101”, and “110”, respectively.
They are 0 ”,“ 1110 ”, and“ 0111 ”. When the retransmission control signal is "1110", that is, when the retransmission permission is given to the mobile station of "101", a collision occurs, but since the conditions cannot be subdivided further, the base stations are generally After the division and the permission are completed, the retransmission control signal “0011” is notified and an instruction to regenerate the random number is issued. Receiving this, the colliding mobile stations generate "010" and "011",
Resending is performed by the subsequent resending control signals “0000” and “0001”.

FIG. 7 shows an operation example in the case where two reserved signals disappear on the split tree for retransmission control due to the capture effect or fading. Here, "001
An example in which a collision occurs because the two reserved signals that have disappeared are retransmitted immediately after the "0" retransmission control signal is transmitted is shown. At this time, the base station returns the split tree for retransmission control to the initial state, and again reports the lower-order digit retransmission permission condition.
In this operation example, since the last one digit of the random number of the mobile station with which the reservation has collided is different, each retransmission control signal "000"
Retransmission is performed by "0" and "0001". Finally, the retransmission control signal "0010" is transmitted again, it is confirmed that there is no signal from the mobile station, and the normal sky line control is resumed.

8 and 9 show a control flow of the base station, FIG. 8 shows a skyline control flow, and FIG. 9 shows a collision resolution flow.

The activated base station first starts to broadcast a skyline signal for skyline control. When the carrier from the mobile station is detected, the signal is received and it is determined whether the received signal has an error. This judgment is based on the CR added to the signal.
C and other signals are used. If there is an error, it is regarded as a signal collision, and control is passed to the collision resolution flow shown in FIG. If there is no error, a prohibition signal is issued as in the case of normal skyline control, and if an EOF (End of File) indicating the end of data transmission from the mobile station is detected, the skyline signal is announced again. Return.

On the other hand, when moving to the collision resolution flow, the base station selects the retransmission control signal to be transmitted next according to the retransmission control division tree (see FIG. 3) and broadcasts the collision resolution signal including the retransmission control signal. To do. Next, the carrier is detected from the mobile station, and if it is not detected, it is determined that the collision resolution period has ended, that is, the immediately preceding retransmission control signal is "001."
It is determined whether it is "0", and if so, the process returns to the sky line control flow shown in FIG. The last retransmission control signal is "0010"
In this case, the selection of the retransmission control signal and the notification of the collision resolution signal and the retransmission control signal are repeated. If a carrier is detected by carrier detection, collision is determined based on the presence or absence of an error in the received signal, and if it is a collision, a new retransmission control signal is selected. Receive. When the data reception is completed, the process returns to the retransmission control signal selection.

10 and 11 show a control flow of the mobile station, FIG. 10 shows a skyline control flow, and FIG. 11 shows a collision resolution flow.

The mobile station which has generated the transmission packet monitors whether or not the skyline signal is broadcast on the downlink channel, and if it is broadcast, transmits the reservation signal, but if not, waits for the skyline signal. Becomes After the reservation signal is transmitted, if the prohibition signal is broadcast on the downlink channel, the data is transmitted, but in the case of the collision resolution signal, the flow goes to the collision resolution flow shown in FIG.

The mobile station that has entered the conflict resolution flow first generates a random number. Next, if the notified retransmission control signal is received, and if it is a retransmission control signal instructing the generation of a random number, a random number is regenerated. Otherwise, the corresponding retransmission permission condition is checked, and if it matches, the reservation signal The mobile station that has transmitted the message receives the subsequent downlink channel, transmits data if the prohibition signal is broadcast and returns to the skyline control flow shown in FIG. 10, and retransmits control if the collision resolution signal is broadcast. Repeat retransmission according to the signal. If the skyline signal is broadcast here, it means that the base station did not recognize the signal of the mobile station for some reason, and the base station has ended the collision resolution period. Returning to the flow, the resending process is performed.

[0040]

In the collision solving type skyline control access method according to the present invention, when there is no collision, a skyline control or a high-efficiency random access combining skyline control and reservation control is performed and a collision occurs. The efficient re-transmission based on the split-tree algorithm enables high throughput and small packet retransmission delay in case of collision.

Since the retransmission control signal for the split tree algorithm can be expressed with a limited amount of information, the control overhead can be reduced and the resources can be effectively used.

Further, even when the signal disappears due to the capture effect, fading, etc., after the sequential transmission of the gymnastics permission signal based on the retransmission control tree is completed, the retransmission permission signal which does not specify the condition is transmitted. It is possible to prevent the effect of the split tree algorithm from being reduced due to the influence.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a wireless packet communication device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation example of the apparatus of the embodiment by a downlink packet from the base station to the mobile station and an uplink packet from the mobile station to the base station.

FIG. 3 is a diagram showing the operation of a split tree algorithm.

FIG. 4 is a diagram for explaining an operation when random numbers match and reset.

FIG. 5 is a diagram showing an operation of a separation tree algorithm before resetting a random number.

FIG. 6 is a diagram showing an operation of a separation tree algorithm after resetting a random number.

FIG. 7 is a diagram showing an operation example in the case where two reservation signals disappear on a split tree for retransmission control.

FIG. 8 is a diagram showing a control flow of a base station and a diagram showing a skyline control flow.

FIG. 9 is a diagram showing a control flow of the base station and a diagram showing a collision resolution flow.

FIG. 10 is a diagram showing a control flow of a mobile station and is a diagram showing a skyline control flow.

FIG. 11 is a diagram showing a control flow of the mobile station and a diagram showing a collision resolution flow.

FIG. 12 is a diagram showing an operation example of ICMA-DR.

FIG. 13 is a diagram showing an operation example of a split tree algorithm.

[Explanation of symbols]

 1 base station 2 mobile station

Claims (8)

[Claims] 1. Since a wireless packet communication is performed between a base station and a plurality of mobile stations under its control using a common packet channel, a prohibition signal indicating that the packet channel is in use from the base station or The mobile station is informed of an empty line signal indicating that it is idle, and each of the plurality of mobile stations starts transmission of an upstream packet to the base station when the empty line signal is informed. In the wireless packet communication method, when uplink packets transmitted simultaneously from two or more of the plurality of mobile stations collide on a packet channel, the base station broadcasts a collision resolution signal instead of a prohibition signal or a skyline signal, It is characterized by prohibiting the transmission of newly generated upstream packets after the occurrence time of the collision packet and allowing the retransmission of only the collision packet. Wireless packet communication method. 2. When an uplink packet collision occurs, each mobile station that has transmitted the packet generates a random number within a predetermined range, and the base station moves the mobile station corresponding to the value of the random number. A station is divided into a plurality of subsets, and a retransmission control signal for granting retransmission permission to each of the subsets in turn is transmitted at the same time as the collision resolution signal, and when a collision occurs again, the subset is further subdivided. Then, the retransmission control signal corresponding to each subdivided subset is sequentially transmitted, and if further subdivision is not possible, the mobile stations belonging to that subset are instructed to regenerate random numbers. The wireless packet communication method according to claim 1, wherein the subset is re-formed, and this operation is repeated until no collision is detected for all the subsets. 3. When a series of sequential transmissions of retransmission control signals from the base station to the subsets are completed, and no collision is detected in the retransmissions from each subset,
The base station transmits a retransmission control signal that permits retransmission to all mobile stations that have transmitted the packet in which the collision has occurred and transmission of the packet has not been completed, and transmit the retransmission control signal to this retransmission control signal. 3. The wireless packet communication method according to claim 2, wherein when no signal is received from any mobile station even after transmission, a series of collision resolution control is ended and the notification of the skyline signal is restarted. 4. The mobile station transmits a reservation signal to the base station before transmitting the packet when transmitting the packet, and the base station notifies the mobile station when the reservation signal is normally received. 4. The wireless packet communication method according to claim 1, wherein transmission permission of the packet is given to the packet. 5. A base station and a plurality of mobile stations that perform wireless packet communication using a common packet channel, wherein the base station is a prohibit signal indicating that the packet channel is in use or an idle state. A means for notifying the plurality of mobile stations of the skyline signal shown is included, and each of the plurality of mobile stations includes means for starting transmission of an upstream packet to the base station when the skyline signal is notified. In the wireless packet communication device, the base station broadcasts a collision resolution signal instead of a prohibition signal or a skyline signal when uplink packets transmitted simultaneously from two or more of the plurality of mobile stations collide on a packet channel. In the case where a collision resolution signal is notified, each of the plurality of mobile stations newly generates after the occurrence time of the packet in which the collision occurs. Wireless packet communication apparatus characterized by comprising means for retransmitting the occurred packet collision prohibits transmission of packet. 6. Each of the plurality of mobile stations includes means for generating a random number in a predetermined range when a packet transmitted by the plurality of mobile stations collides with each other, and the base station includes: The mobile stations are divided into a plurality of subsets corresponding to the values of the random numbers respectively generated, and a retransmission control signal for sequentially granting retransmission permission to each of the subsets is transmitted at the same time as the collision resolution signal. The wireless packet communication according to claim 1, further comprising means and means for instructing a mobile station belonging to the subset to regenerate a random number if the collision is not resolved even after performing a predetermined number of divisions. apparatus. 7. The base station transmits a packet in which a collision occurs when the base station completes a series of retransmission control signal transmissions to a subset and no collision is detected in retransmissions from each subset. Means for transmitting a retransmission control signal that permits retransmission to all mobile stations that have completed the transmission of the packet, and even if this retransmission control signal is transmitted, any mobile station 7. The wireless packet communication method according to claim 6, further comprising: means for ending a series of collision resolution control and restarting notification of a skyline signal when no signal is received. 8. The mobile station includes means for transmitting a reservation signal to the base station prior to the transmission of the packet when transmitting the packet, the base station making a reservation when the reservation signal is normally received. 8. The wireless packet communication method according to claim 5, further comprising means for giving permission to transmit the packet to the mobile station that has transmitted the signal.