Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Reexamination Certificate
1999-12-06
2002-12-10
Maung, Nay (Department: 2681)
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
C455S423000
Reexamination Certificate
active
06493540
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to communication random access control system at the time of collision of transmission start timings in a mobile radio system and, more particularly, a radio random access control system (method and apparatus) for suppressing non-transmission time interval as much as possible by improving the random delay in the mobile station.
In the prior art communication random access control system, upon collision of the transmission start timings of two or more mobile stations as a result of random transmission of a plurality of mobile stations to the base station, a random delay is generated in a mobile station with no transmission start timing allotted thereto, and the transmission start timings are controlled such that the transmission start timings of the mobile stations, which previously encountered the transmission start timing collision, will not collide again. However, since the random generation is generated in a simple method, unnecessarily long non-transmission or vacant time intervals are generated to deteriorate the data transmission rate in radio time interval.
FIG. 8
is a view showing the status of collision of the transmission start timings of two mobile stations in the prior art.
FIG. 9
is a view showing the status of collision of the transmission start timings of three mobile stations in the prior art.
FIG. 8
illustrates operation in the prior art system in case when a collision occurs at transmission start timings of two mobile stations. In the Figure, a time axis extends from left to right. Each slot includes collision control bits (E, for instance I, N and PE=0). Mobile stations #
1
and #
2
receiving a signal from a base station analyze collision control bits (E) transmitted therefrom, and checks whether the base station is in an idle (I) or a busy (B) state. In the case of
FIG. 8
, the first slot #
0
from the left end indicates that the base station is in the idle state. Thus, the mobile stations #
1
and #
2
start the transmission of data to the base station in the same way.
When the base station could receive mobile station data at the timing of the next slot #
0
, it sets a “received” (R) bit in the collision control bits. When the base station could not receive any data, it sets a “not received” (N) bit in the collision control bits.
In the case of
FIG. 8
, however, the two mobile stations simultaneously transmit the at the same timing of the same frequency. Therefore, the base station can not receive the two data from the mobile stations #
1
and #
2
due to the radio wave interference, and consequently sets the “not received” (N) bit in the collision control bits (E).
Receiving the “not received” bit in the collision control bits set by the base station, the mobile stations #
1
and #
2
delay the operation of data transmission to the base station by generating random numbers within a maximum fixed number of 500 ms and setting delay times corresponding to the generated random numbers. (This operation is referred to as random delay operation.) In the case of
FIG. 8
, it is assumed that the random delay time set by the mobile station #
1
is shorter and about 20 ms. Thus, checking the collision control bits in the third slot #
0
from the left and finding that the base station is in the idle (I) state, the mobile station #
1
starts transmission. In the subsequent fourth slot #
0
from the left end, the mobile station #
1
receives the signal other than “0” as bits “R” and “PE” (set as the same data as the CRC result of the transmitted data) indicating that the transmitted data has been received in the base station side. This means that the mobile station #
1
succeeded in the transmission. Since the data transmitted from the mobile station #
1
has such a length that its transmission can be completed in one slot, terms “FIRST” and “LAST” are used in the Figure.
It is also assumed that the random delay time set by the mobile station #
2
is 55 ms. The mobile station #
2
thus can receive the collision control bits in the fourth slot #
2
from the left end right after this delay time. Since the base station is found to be capable of receiving the data at this time, the mobile station #
2
starts the transmission. In the fifth slot #
2
from the left end bits “R” and “PE
0
” indicative of normal reception of the data transmitted from the mobile station #
2
has been set. In addition, the data transmitted from the mobile station #
2
covers three slots, and also it has been made clear that the mobile station #
2
will continue transmission at the next slot timing. Thus, bit “B” indicative of the busy state has been set.
It will be seen from the operation shown in
FIG. 8
that no “non-transmission interval” is generated even when the data from two mobile stations collide with each other. In
FIG. 8
, the “non-transmission interval” is shown to be shorter for the sake of the scale.
FIG. 9
, like
FIG. 8
, illustrates the prior art system operation. This case, however, concerns with a collision of data transmitted from three mobile stations, and the mobile stations #
1
to #
3
set random delay times of about 86, about 40 and about 60 ms, respectively, by generating random numbers. Like the case of
FIG. 8
, no “non-transmission interval” is generated.
SUMMARY OF THE INVENTION
In view of the above background, it is an object of the present invention to provide a radio random access control method capable of improving the random delay in the mobile station to suppress the non-transmission time interval for effective utilization of the radio time interval.
According to an aspect of the present invention, there is provided in a mobile radio communication system in which each of a plurality of mobile stations and a base station randomly transmits and receives data to and from each other, a radio random access control system in which each mobile station receives all data from the base station, executes an analysis of destination mobile stations of the received data, obtains from the analysis result the number of mobile stations currently transmitting or receiving the data to or from the base station in a radio zone, in which the own station is present, and calculates delay time after a transmission timing collision at the time of the start of transmission of the own mobile station till the next start of transmission according to the obtained number of mobile stations excluding the own station.
The maximum value of the calculated delay time is time obtained by multiplying the number of mobile stations with data transmitted thereto by a unit time.
According to another aspect of the present invention, there is provided in a mobile radio communication system in which each of a plurality of mobile stations and a base station can randomly transmit and receive data to and from each other, a radio random access control system, wherein each mobile station comprises a transmitting/receiving antenna, a transmitting circuit for transmitting radio signals to the base station, a modulating circuit, a receiving circuit for receiving radio communication data from the base station, a demodulating circuit for converting the received data to binary data, and a controller for executing a de-scrambling analysis of the binary data thus obtained to binary data, and executing an analysis of destinations included the data transmitted from the base station, detecting the number of destination mobile stations of data received in a certain fixed time interval and calculating the delay time after a transmission timing collision at the time of the start of transmission from the own station till the next start of transmission according to the detected number of mobile stations exclusive of the own station.
The controller includes a signal decoding unit for executing a de-scrambling analysis of the obtained binary data to binary data, a destination judging unit for analyzing destinations contained in the data received fr
Gelin Jean A
Maung Nay
LandOfFree
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