JP2993474B2 - Wireless packet access system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio packet communication system for a mobile communication system, in which a mobile station reports the status of an uplink slot used for information transmission by a base station using downlink slot control information. The present invention relates to a wireless packet access system in which the mobile station determines transmission / reception of information based on information. Note that the term “uplink” means the direction from the mobile station to the base station, and the term “downlink” means the direction from the base station to the mobile station.

[0002]

2. Description of the Related Art A plurality of mobile stations share a radio slot,
ICMA as an access control method for transmitting information
(Idle Channel Multiple Ac
ess), ICMA-PE (Idle-signal)
Casting Multiple Access
for example, with Partial Echo). The ICMA-PE transmits collision control information including the use status of the uplink slot (vacant / occupied), the reception status from the mobile station (reception / non-reception, and a part of the uplink information transmitted from the mobile station). Is a method of notifying the mobile station of a downlink slot, and the mobile station determines an access operation of a next uplink slot based on information from the base station.

FIG. 1 is a configuration diagram of a conventional wireless packet access system. In FIG. 1, reference numerals 11a to 11n denote mobile devices, and 12 denotes a mobile device 1 located in a zone managed by itself.
1 and base stations 13a to 13c that communicate with each other by radio.
2 are downlink slots for transmitting information to the mobile station 11, and 14a to 14b are uplink slots for transmitting information from the mobile station 11 to the base station 12.

FIG. 8A shows a conventional IC.
FIG. 3 is a configuration diagram illustrating a configuration of a downlink slot transmitted from the base station 12 to the mobile device 11 in the MA-PE. In FIG. 8A, reference numeral 80 denotes a downlink slot, which is the same as the downlink slot 13 shown in FIG. 1, 81 denotes a downlink information signal, and 82 notifies the mobile station 11 of the use status of the uplink slot corresponding to the downlink slot 80. Collision control information,
An empty line / prohibition bit (I / B, I: Idle, B: 83) indicates whether or not the upstream slot is being used by the mobile station 11.
Busy), 84 are reception / non-reception bits (R / N, R: Receive, N: N) indicating whether or not information transmitted from the mobile station 11 in the uplink slot has been received by the base station 12.
Reference numeral 85 denotes a partial echo field (PE: Partial Echo) in which the base station 12 partially folds information transmitted in the uplink slot.

[0005] The empty line / prohibition bit 83 of the downstream slot is set by the base station 12 when the upstream slot is not used, and the prohibited line (B) is set when the upstream slot is in use. The reception / non-reception bit 84 of the downlink slot is set by the base station 12 when the information from the mobile station 11 can be received in the uplink slot, and is not received (N) when the information is not received. Is set.

[0008] FIG. 8B is a configuration diagram showing a configuration of an uplink slot transmitted from the mobile station 11. FIG.
In (b), reference numeral 86 denotes an uplink slot, which is the same as the uplink slot 14 shown in FIG. 1. Reference numeral 87 divides information transmitted from the mobile station 11 into slots of a certain length, and transmits the information when transmitting. It indicates the number of remaining slots of power information, 88 is actual information transmitted from the mobile station 11 to the base station 12, and 89 is information for determining the presence or absence of an error in the received information.

[0007] The information of these uplink slots is stored in the mobile station 11.
Is set by

[0008]

In wireless packet communication in which a plurality of mobile stations share slots and transmit information, when information is simultaneously transmitted in the same uplink slot from a plurality of mobile stations, a base station is required to transmit information. A mobile station to communicate with may be determined by a capture effect in which information from a mobile station with a large received power survives.

[0009] This capture effect is a factor that improves the throughput characteristics as compared with the wired access method, while the received power at the base station generally increases as the distance from the mobile device decreases. There is a problem that the distance between the mobile station and the base station causes unequal information transmission. In other words, if a mobile station located near the base station and a mobile station located far from the base station transmit information at the same time, the mobile station located near the base station is not information from the mobile station located far from the base station. There is a high possibility that the information from the mobile station that performs the communication can be received by the base station.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless packet access system which solves an advantage / disadvantage of information transmission depending on a distance between a mobile station and a base station. With the goal.

[0011]

According to a first aspect of the present invention, there is provided a wireless packet access system, comprising: a mobile device moving over a plurality of zones; and a wireless device provided in a zone where the mobile device is located, and wirelessly connected to the mobile device. And a base station for communication, wherein a plurality of mobile stations share a downlink slot for transmitting information from the base station to the mobile station and an uplink slot for transmitting information from the mobile station to the base station. The base station broadcasts control information indicating “free” or “occupied” as the use status of the uplink slot, and when the mobile station intends to transmit information to the base station, If the control information indicates “up” in the uplink slot, transmit information in the uplink slot; if the control information from the base station indicates “blocked” in the uplink slot, Sending In the wireless packet access system, the mobile station includes a measuring unit for measuring the received power of the downlink slot received from the base station, and when the received power of the downlink slot measured by the measuring unit is large, The mobile device includes means for increasing the time until transmitting information to the slot and shortening the time for transmitting information to the uplink slot when the measured reception power of the downlink slot is small. .

Further, in the radio packet access system according to the second invention, when the base station normally receives information from the mobile station, the base station returns a part of the information received from the mobile station. When the return information received from the base station is part of the information transmitted by the mobile station, the mobile station continuously transmits the subsequent information, and transmits information other than the transmitted information. If a part of the information is set in the control information from the base station and received, the transmission of the subsequent information is postponed, and when the information is retransmitted, the transmitting means for transmitting with higher output than the previous information transmission is used. Is provided.

[0013] Also, in the wireless packet access system according to a third aspect of the present invention, the mobile station transmits power from the base station to the base station when the mobile station attempts to transmit information. If the control information on the uplink slot indicates “blocked” and the measured reception power is large, the delay time until receiving the control information from the base station again and determining whether transmission is possible is increased. If the measured received power is small, the control means is provided to reduce the delay time.

Further, in the radio packet access system according to the fourth invention, after the mobile station transmits information in the uplink slot, a part of information other than the transmitted information is set in control information from the base station and received. In this case, there is provided a delay control means for reducing a delay time from receiving control information from the base station again and determining whether transmission is possible or not.

[0015] Further, the radio packet access system according to the fifth invention is characterized in that, when the mobile station tries to transmit information, if the control information on the uplink slot from the base station indicates "blocked", Queuing means for receiving control information of a downlink slot from the base station and performing a delay time queuing to determine whether or not transmission is possible;
After receiving control information indicating and transmitting information to the uplink slot,
The information processing apparatus further includes a queuing unit that waits for information transmission until the control information on the uplink slot from the base station becomes “empty” again.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a configuration diagram of a wireless packet access system according to the present invention. In FIG. 1, 11a-1
1n is a mobile station, 12 is a base station that wirelessly communicates with the mobile station 11 located in a zone managed by itself, 13a to 13c are downlink slots for transmitting information from the base station 12 to the mobile station 11, 14a to 14b is the mobile station 11 to the base station 12
Is an upstream slot for transmitting information.

FIG. 2 is an explanatory diagram showing an operation of communication between the base station and the mobile station, showing one embodiment of the wireless packet access system according to the present invention.

Next, the operation of this embodiment will be described with reference to FIGS. In FIG. 2, downlink slot 2
It is assumed that the I / B 1a indicates I, that is, "vacant", and that the mobile device 11a has information to be transmitted.
Further, it is assumed that the I / B of the downlink slot 21c indicates I, that is, "free", and that the mobile device 11b has information to be transmitted. The mobile device 11a measures the received power Ra of the downlink slot 21a. The mobile device 11b measures the received power Rb of the downlink slot 21c. Generally, in radio wave transmission / reception, the relationship between distance and reception power is such that the longer the distance between transmission and reception, the lower the reception power, and the reception power in free space decreases in proportion to the square of the distance.

Therefore, based on the received power measured by mobile station 11, mobile stations 11a and 11b determine an uplink slot for actually transmitting information. For example, the received power Ra
Is larger than the received power Rb. The mobile station 11a having a large received power value is the I / B of the next downlink slot 21b.
Is checked, and since it indicates I, that is, “empty”, information is transmitted in the uplink slot 22a. Also, the mobile station 11b having a small received power value transmits information in the next uplink slot 22c. By performing such control, for example, when the mobile stations 11a and 11b have information to be transmitted in the same downlink slot, the mobile station 11b having a small received power value
By transmitting information in the next uplink slot, it becomes possible to transmit information in preference to the mobile station 11a having a higher received power value.

According to this embodiment, the mobile station transmits the uplink information of the mobile station located at a short distance with a large received power value after a certain period of time based on the received power of the downlink slot from the base station. By shortening the time until transmission of uplink information of a mobile station located at a long distance with a small power value, the information reception power of the base station generated based on the distance between the base station and each mobile station due to the distance from the mobile station is reduced. This has the effect of eliminating equality.

Embodiment 2 FIG. FIG. 3 is an explanatory diagram focusing on an uplink slot and a downlink slot between the base station and the mobile device and the mobile device 11 in FIG. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. 31a-31
c is a downlink slot from the base station 12, and 32a and 32b are uplink slots from the mobile device 11 to the base station 12.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 3, the I / O of the downlink slot 31a is
B indicates I, that is, “empty”, and the mobile units 11a and 11
It is assumed that b has information to be transmitted. In this case, the mobile devices 11a and 11b transmit information in the uplink slot 32a which is the information transmission timing. Here, mobile device 1
It is assumed that information from the mobile station 11a can be received by the base station 12 because the reception power from the mobile station 11b is larger than that of the mobile station 11b because 1a is closer to the base station than 11b.

The base station 12 determines the state of the next uplink slot in the downlink slot 31b and the status of the previous uplink slot 3
The reception status in 2a is notified. That is, as the collision control information, B is set to I / B, that is, “prohibited” meaning that reception other than the mobile device 11a is prohibited, and R, which indicates that the previous uplink slot has been received, is set to R / N. Is set, and a part of the information received from the mobile device 11a is set in the PE for the return in order to further specify the mobile device that has successfully received the data.

Next, upon receiving the downlink slot 31b from the base station 12, the mobile station 11a receives the downlink slot 31b.
Based on the collision control information of b, it is determined that information can be continuously output, and information is transmitted in the subsequent uplink slot. In the slot in which the information has been transmitted, the mobile device 11b is not the information transmitted by itself, After recognizing that the information transmitted by another mobile device has survived, transmission of subsequent information is stopped.

Here, the mobile station 11b determines that the reception power at the base station 12 is higher in the other mobile stations 11 than it is, so that the mobile station 11b retransmits information next time or after a predetermined delay. The collision control information of the downlink slot is checked, and if the I / B is I, that is, “empty”, the transmission power, for example, one level (such as twice) determined by the system is higher than the transmission power S1 of the information transmission in the uplink slot 32a. Electric power S
2. Information is transmitted.

According to this embodiment, the information transmission from another mobile station survives at the time of information transmission, and the mobile station disadvantageous to the information transmission raises the output in the next information retransmission, so that the mobile station and the base station can communicate with each other. This has the effect of eliminating inequality due to the distance to the station.

Embodiment 3 FIG. 4 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention. In FIG. 1, the uplink slot and the downlink slot between the base station 12 and the mobile station 11 in FIG. It is explanatory drawing which paid attention. 4, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. 41a to 41c are base stations 1
2, downlink slots 42a to 42c are uplink slots from the mobile station 11 to the base station 12.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 4, it is assumed that the mobile units 11a and 11b have information to be transmitted at the timing of the downlink slot 41a. Here, the mobile units 11a and 11b check the collision control information set in the downlink slot 41a. Since the I / B of the collision control information is set to B, that is, “prohibited”, information cannot be transmitted to both mobile stations 11a and 11b, and the mobile stations 11a and 11b wait. The waiting time for waiting in each of the mobile devices 11a and 11b is determined based on the reception power of the downlink slot 41a.

For example, the received power Ra of the mobile device 11a is
If the received power is higher than the reception power Rb of the mobile device 11b, the mobile device 1
The standby time at 1a is a random time of the average Ta, and the standby time at the mobile device 11b is a random time of the average Tb, and is controlled by the received power value so that Tb is smaller than Ta. That is, when the reception power of the information from the base station 12 is large, the average standby time is long, and when the reception power is low, the average standby time is short. The mobile device 11b checks the collision control information of the downlink slot 41b after the average standby time Tb, and transmits the information in the uplink slot 42b if the I / B is I, that is, “empty”.

The mobile station 11a checks the collision control information of the downlink slot 41c after the average standby time Ta longer than the average standby time Tb of the mobile station 11b. Information is transmitted in the slot 42c.

According to the present embodiment, a mobile station located far from the base station and disadvantageous for information transmission, if the uplink slot is being used by another mobile station and cannot transmit information, does not transmit information. By shortening the waiting time, the mobile station 11 which is close to the base station and is advantageous for information transmission
It is possible to monitor the downstream slot in a shorter cycle, and to compensate for the disadvantage of information transmission.

Embodiment 4 FIG. FIG. 5 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention, and is an explanatory diagram focusing on the uplink slot, the downlink slot, and the mobile device between the base station and the mobile device in FIG. is there. 5, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. 51a to 51d are downlink slots from the base station 12, and 52a to 52c are uplink slots from the mobile station 11 to the base station 12.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 5, it is assumed that the mobile device 11b has information to be transmitted at the timing of the downlink slot 51a. Here, the mobile device 11b checks the collision control information set in the downlink slot 51a. Since the I / B of the collision control information is set to B, that is, "prohibited", the mobile device 11b cannot perform information transmission and waits.

The waiting time for this waiting is, for example, a random time of the average T1. After waiting, the mobile device 11b checks the collision control information of the downlink slot 51b. Since the I / B of the collision control information is set to I, that is, “empty”, the mobile station 11b determines that the information can be transmitted, and attempts transmission in the uplink slot 52b.

Further, at this timing, the mobile station 11a also has information to transmit, and performs transmission in the same uplink slot 52b. Then, the mobile device 11a becomes the mobile device 11b.
It is assumed that the information of the mobile station 11a is received by the base station 12 because the received power from the mobile station 11a is larger than the mobile station 11b because the mobile station 11b is closer to the base station 12.
The base station 12 reports the next up slot state in the down slot 51c and the reception state in the previous up slot 52b. That is, as the collision control information, B
That is, "prohibited" is set, R / N is set to R, that is, "received", and part of the information received from the mobile device 11a is set in the PE for return.

When the mobile station 11a receives the downlink slot 51c, it determines that information can be continuously output based on the collision control information of the downlink slot 51c, and transmits information in the subsequent uplink slots. Recognizes that the information transmitted by the other mobile station 11 in the slot transmitted by itself has survived, and stops transmitting information. Here, mobile device 1
1b waits until the next information is transmitted.

The waiting time in this case is, for example, a random time of the average T2. This average time T2 is
The time is shorter than the previous average waiting time T1. And
The mobile device 11b checks the I / B of the collision control information of the downlink slot 51d again after the elapse of the standby time T2. This time, since the I / B is set to I, that is, “free”, information is transmitted in the uplink slot 52c.

That is, the mobile station 11b transmits the collision control information I
The average standby time required to wait for collision due to information transmission must be shorter than the average standby time when / B is set to B, that is, “prohibited”.

According to this embodiment, when a mobile station located far from the base station determines that information transmission from another mobile station survives at the time of information transmission and that the information transmission is disadvantageous, the uplink slot becomes When the mobile station 11 is used by another mobile station and cannot transmit information, the mobile station 11 waits for a shorter time than the waiting time. Monitoring can be performed, and the disadvantage of information transmission can be compensated.

Embodiment 5 FIGS. 6 and 7 are explanatory diagrams showing another embodiment of the wireless packet access system according to the present invention. In FIG. 6, an uplink slot and a downlink slot between a base station and a mobile station in FIG. It is explanatory drawing which paid attention. 6 and 7, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. 61a, 61b, and 7
1a to 71c are downlink slots from the base station, 62a, 6
2b and 72a to 72c are the base stations 1
2 shows an uplink slot to 2.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described with reference to FIG. In FIG. 6, it is assumed that the mobile station 11b has information to be transmitted at the timing of the downlink slot 61a. Here, the mobile station 11b has a downlink slot 61a.
Check the collision control information set in. Since the I / B of the collision control information of the downlink slot 61a is set to B, that is, "prohibited", the mobile station 11b cannot perform information transmission and waits. The waiting time for this waiting is, for example, a random time of the average Tb. After the mobile device 11b waits, it checks the collision control information of the downlink slot 61b. I / B of collision control information of downlink slot 61b
Is set to I, that is, “empty”, so that the mobile device 11b
Is capable of transmitting information and performs transmission in the uplink slot 62b.

In FIG. 7, since the mobile station 11b has information to be transmitted at the timing of the downlink slot 71a, the mobile station 11b determines that the information can be transmitted, so that Try sending. Further, the mobile station 11a also has information to transmit at the same timing, and performs transmission in the same uplink slot 72a.

Here, because the received power from the mobile device 11a is larger than the received power from the mobile device 11b because the mobile device 11a is closer to the base station than the mobile device 11b, the information of the mobile device 11a is transmitted to the base station. 12 is assumed to be received.

The base station 12 sets the state of the next uplink slot in the downlink slot 71b and the state of the previous uplink slot 72a.
To inform the reception status at. That is, as collision control information of the downlink slot 71b, I / B is set to B, ie, “prohibited”, R / N is set to R, ie, “received”, and PE is set to one of the information received from the mobile device 11a. Set the part for folding.

Based on the collision control information of the downlink slot 71b, the mobile station 11a determines that information can be continuously output,
Information is transmitted in the subsequent uplink slot, and the mobile station 11b
Recognizes that the information transmitted by the other mobile station 11 instead of the information transmitted by itself in the slot where the information has been transmitted has survived, and stops transmitting the information. Here, the mobile device 11b waits until the next information is transmitted.

In this case, the mobile station 11b constantly monitors the downlink slot collision control information and continues to wait until the I / B becomes I. The mobile station 11a performs the final information transmission in the uplink slot 72b, and the base station 12 sets I, ie, “empty” to the I / B in the collision control information of the downlink slot 71c, and sets the R / N
Is set to R, that is, "received", and a part of the information received from 11a is set to PE. When confirming that the I / B of the collision control information of the downlink slot 71c is I, that is, "free", the mobile station 11b transmits information in the uplink slot 72c.

That is, if the uplink slot is in use at the transmission timing of the mobile station 11, the mobile station 11 waits for a certain delay time, and if the uplink slot is empty, the information transmitted collides with the information transmitted by another mobile station. If the information transmitted by another mobile device, but not the information transmitted by the user, survives, the information is transmitted again at the timing when the transmission of the other mobile device is completed.

According to this embodiment, when a mobile station located far from the base station transmits information from a mobile station located near another base station at the time of transmitting information, the information transmission is disadvantageous. If it is determined that there is, the information transmission is performed at the timing when the information transmission of another mobile station existing near the base station is completed, so that the disadvantage of the information transmission can be compensated.

[0049]

According to the first aspect of the present invention, based on the received power of the downlink slot from the base station, the mobile station transmits uplink information of a mobile station located at a short distance having a large received power value with a certain time interval. Eliminates inequality due to the distance from the mobile station in the base station, which is generated based on the distance between the base station and each mobile station, by shortening the time required for transmitting the uplink information of the mobile station at a long distance with a small received power value This has the effect that it becomes possible to

According to the second aspect of the present invention, the information transmission from another mobile station survives at the time of information transmission, and the mobile station disadvantageous to the information transmission increases the output in the next information retransmission. And inequality due to the distance between the base station and the base station can be eliminated.

According to the third aspect of the present invention, a mobile station located far from the base station and disadvantageous for information transmission is used when an uplink slot is used by another mobile station and information cannot be transmitted. By shortening the time for waiting for information transmission, it is possible to monitor downlink slots in a shorter cycle than a mobile station that is close to the base station and is advantageous for information transmission, thereby compensating for the disadvantage of information transmission. Play.

According to the fourth aspect, when a mobile station located far from the base station determines that information transmission from another mobile station survives at the time of information transmission and that information transmission is disadvantageous, When the upstream slot is used by another mobile station and waiting for less than the waiting time when information cannot be transmitted, the downlink slot is shorter than the mobile station that is near the base station and advantageous for information transmission. Can be monitored, and the disadvantage of information transmission can be compensated.

According to the fifth invention, when a mobile station located far from the base station determines that information transmission from another mobile station survives at the time of information transmission and that information transmission is disadvantageous, By transmitting information at the timing when transmission of information on mobile devices existing near the base station is completed, it is possible to compensate for disadvantages of information transmission.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of the present invention and a conventional wireless packet access system.

FIG. 2 is an explanatory diagram showing an operation of communication between a base station and a mobile station, showing one embodiment of a wireless packet access system according to the present invention.

FIG. 3 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention.

FIG. 4 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention.

FIG. 5 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention.

FIG. 6 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention.

FIG. 7 is an explanatory diagram showing another embodiment of the wireless packet access system according to the present invention.

FIG. 8 is a configuration diagram showing a configuration of a downlink slot transmitted from a base station to a mobile station and an uplink slot transmitted from the mobile station in a conventional ICMA-PE.

[Explanation of symbols]

 11a-11n Mobile station 12 Base station 13a-13c Down slot 14a, 14b Up slot 21a-21c Down slot 22a-22c Up slot 31a-31c Down slot 32a, 32b Up slot 41a-41c Down slot 42a-42c Up slot 51a- 51d downlink slots 52a to 52c uplink slots 61a, 61b downlink slots 62a, 62b uplink slots 71a to 71c downlink slots 72a to 72c uplink slots 80 downlink slot configurations 81 downlink control signals 82 collision control information 83 empty / prohibited bits (I / B 84 received / non-received bits (R / N) 85 partial echo field 86 uplink slot configuration 87 length information 88 uplink information signal 89 error control code, etc.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/26 H04L 12/28-12/66 H04Q 7/00-7/38

Claims (5)

(57) [Claims] 1. A mobile station that moves across a plurality of zones, and a base station provided in a zone where the mobile station is located and communicates wirelessly with the mobile station. A downlink slot for transmitting information from a station to the mobile station and an uplink slot for transmitting information from the mobile station to the base station are shared, and the base station is `` empty '' as the usage status of the uplink slot, When the mobile station attempts to transmit information to the base station, the control information from the base station indicates "free" in an uplink slot. In the wireless packet access system for transmitting information in an uplink slot, and when the control information from the base station indicates “blocking” of the uplink slot, the mobile station Measuring means for measuring the reception power of the downlink slot received from the base station; if the reception power of the downlink slot measured by the measurement means is large, increase the time until information is transmitted to the uplink slot; And a means for shortening the time required for transmitting information to the uplink slot when the measured reception power of the downlink slot is small, the mobile station being provided with a means. 2. When the base station normally receives information from the mobile station, the base station notifies control information of a part of the information received from the mobile station, and the mobile station transmits If the return information received from the base station is part of the information transmitted by the mobile device, the subsequent information is continuously transmitted,
If some information other than the transmitted information is set in the control information from the base station and received, the transmission of the subsequent information will be postponed, and when the information is retransmitted, the output will be higher than the previous information transmission and transmitted. 2. The wireless packet access system according to claim 1, wherein the mobile device is provided with the means. 3. A mobile station, comprising: a power measuring means for measuring a reception power of a downlink slot from a base station; and control information on an uplink slot from the base station indicating "blocked" when information is to be transmitted. If the measured received power is large, increase the delay time until receiving the control information from the base station again to determine whether transmission is possible, and if the measured received power is small, 2. The wireless packet access system according to claim 1, further comprising control means for reducing the delay time. 4. The mobile station, after transmitting information to an uplink slot,
When some information other than the transmitted information is set as control information from the base station and received, the delay time until the control information from the base station is received again and it is determined whether transmission is possible is reduced. 3. The wireless packet access system according to claim 2, further comprising delay control means. 5. The mobile station receives control information of a downlink slot from the base station again when control information on an uplink slot from the base station indicates “occupied” when transmitting information. Queuing means for performing a delay time queuing to determine whether transmission is possible;
After receiving control information indicating "empty" as the state of the uplink slot from the base station and transmitting information to the uplink slot, waiting for information transmission until the control information on the uplink slot from the base station becomes "empty" again 3. The wireless packet access system according to claim 2, further comprising means.