JP2002335568A - Control channel transmitting method in time division multiplex system, control station apparatus for the same, reception method for control channel and reception apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for avoiding transmission of a control channel at the same timing from two control stations. SOLUTION: The device is provided with a transmission timing setting means 10 selecting and setting one of a plurality of different control channel transmission timing, a temporary transmission stop means 20 setting which time slot in control channel transmission timing selected by the transmission timing setting means to a transmission stop slot, a control channel generation means 40, a transmission means 30 transmitting the control channel by the control channel generation means, a judging means 60 judging whether the control channel is that of a self-station or not when the control channel is received by a reception means 50 by the transmission stop slot and a selection change means 70 selecting different control channel transmission timing by the transmission timing setting means when it is not the control channel of the self-station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication technology such as a mobile communication system and a wireless LAN.

[0002]

2. Description of the Related Art In wireless communication in which a large number of terminal stations (portable terminals such as mobile phones or cordless phones or wireless LANs must be controlled) must be controlled, a control station (a cordless phone or wireless LAN has a parent station). ) Transmits a control channel called a beacon, and the terminal station that receives it grasps the existence of the control station and the contents of the instruction, so that communication is executed so as not to interfere with each other. You.

[0003] A control channel must be correctly received by all terminal stations controlled by one control station. For example, in the case of a cellular mobile communication system, there are areas where control channels of a plurality of control stations overlap, but a terminal station must be able to distinguish and receive exactly which control station is the control channel. Thus, frequency division multiplexing (FDM), code division multiplexing (CDM), time division multiplexing (T
DM) and the like, the control channels for each control station are orthogonalized so that the terminal stations can distinguish them.

[0004]

In UWB (Ultra Wide Band) wireless communication, which is currently being put into practical use, orthogonalization by frequency division and code division is difficult. There is a situation in which a time division multiplexing method for transmitting a channel must be adopted.
However, in the case of this method, the possibility that the control stations having overlapping transmission areas transmit the control channel at the same timing cannot be reduced to zero, so that even if two control stations transmit the control channel at the same timing, It is necessary to consider a method that can avoid this.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a control channel transmission method for wireless communication in which a control channel is transmitted by a time division multiplexing method. A transmission stop process for stopping transmission in a predetermined time slot, a reception confirmation process for checking whether a control channel is received in the time slot in which the transmission is stopped, and another process when reception of the control channel is confirmed. And a timing change step of changing to the control channel transmission timing.

According to this method, the control station interrupts the control channel transmission at any time slot in the current control channel transmission timing, and if the control channel is received at this time, somewhere. It can be determined that another control station is transmitting the control channel at the same timing. Therefore, in this case, by changing the transmission timing of the own station to another timing, it is possible to avoid collision of the control channel.

In the timing change process, when the reception of the control channel is confirmed, the step of identifying the transmitting station of the control channel is compared with the priority of the identified transmitting station and its own station. If the own station has a higher priority, the current control channel transmission timing is maintained, and if the own station has a lower priority, a step of changing to another control channel transmission timing can be executed. .
In other words, if the control stations with overlapping timings shift their timing with each other, there is a possibility that the changed timing will also overlap.Therefore, it is necessary to give priority to changing the timing for each control station. Therefore, a more reliable method is used to avoid overlapping timing changes.

According to the present invention, as a control station apparatus for realizing the above control channel transmission method, a transmission timing setting means for selecting and setting one of a plurality of different control channel transmission timings, Transmission pause means for setting one of the time slots in the control channel transmission timing to a transmission stop slot, control channel generation means for generating a control channel of the own station, transmission timing setting means and transmission pause means. A control unit for transmitting the control channel by the control channel generating unit at the control channel transmission timing, a receiving unit for receiving the control channel, and the control unit receiving the control channel in the transmission stop slot by the transmission temporary stop unit In this case, control by the control channel generation means of the own station A control station device comprising: a determination unit for determining whether the channel is a channel; and a selection changing unit for causing the transmission timing setting unit to select another control channel transmission timing when the result of the determination is that the control channel is not the control channel of the own station. suggest.

The selection changing means generates a unique number of the own station and sends it to the control channel generating means to be included in the control channel, and the result of the judgment by the judging means is not the control channel of the own station. In this case, the unique number extracting means for extracting the unique number from the control channel received by the receiving means, and comparing the extracted unique number with the unique number of the own station to determine the priority order, the own station has a higher priority. Priority order determining means for causing the transmission timing setting means to select another control channel transmission timing when the order is lower.

[0010]

FIG. 1 is a block diagram showing a specific example of a control station apparatus according to the present invention.

The control station device includes a transmission timing setting means 10 for selectively setting any one of a plurality of different control channel transmission timings, and a time slot in the control channel transmission timing selected by the transmission timing setting means. Transmission suspending means 20 for setting a transmission channel to a transmission stop slot, a control channel generating means 40 for generating a control channel of its own station,
0, a transmission unit 30 for transmitting a control channel by the control channel generation unit 40 at a control channel transmission timing according to the transmission suspension unit 20, a reception unit 50 for receiving the control channel, and a transmission by the transmission suspension unit 20. When the control channel is received by the receiving unit 50 in the stop slot, the determining unit 60 determines whether the control channel is the control channel by the control channel generating unit 40 of the own station. And a selection changing unit 70 for causing the transmission timing setting unit 10 to select another control channel transmission timing.

The transmission timing setting means 10 is capable of generating three types of control channel transmission timings: a first transmission timing, a second transmission timing, and a third transmission timing. , And a selector MUX. The first transmission timing is the timing for transmitting the control channel in the 1, 3, 7, 15, and 40th time slots on the time axis, and the second transmission timing is the 2, 8, 22, 23, and 31st time slots on the time axis. And the third transmission timing is 4, 6, 21, 26, 39 on the time axis.
The timing for transmitting the control channel is at the time slot.

The transmission suspending means 20 suspends transmission not to transmit during the control channel transmission timing set by the transmission timing setting means 10 at a predetermined probability according to a random timing generator (not shown) provided therein. Set the slot. The transmission means 30 transmits the control channel generated by the control channel generation means 40 according to the transmission timing determined via the transmission suspension means 20.

The control channel generating means 40 generates, as a control channel, a bit string representing the content of a control instruction to be notified to a terminal station to be managed by the own station in accordance with the status of wireless communication. The transmitting means 30 receives the bit string,
The signal is transmitted from the antenna as a radio wave in the time slot of the transmission timing determined via the transmission temporary means 20. The transmitting means 30 of this example is an ultra wideband (Ultra Wi
deband: UWB) It will be explained as a transmission system,
The present invention is not limited to this. Ultra wideband transmission is basically based on very fine pulse width
Baseband transmission is performed using a signal composed of a pulse train (for example, 1 ns (nanoseconds or less)). The occupied bandwidth is calculated by dividing the occupied bandwidth by its center frequency.
(E.g., 1 GHz to 10 GHz) is a bandwidth on the order of GHz such that a value obtained by dividing by about 1 is approximately 1, and includes a W-CDMA system, a cdma2000 system, and an SS (Spread Spectrum).
m) and OFDM (Orthogonal Frequency Division Multipl
exing) compared to the bandwidth used in the wireless LAN.

[0015] The ultra-wide band transmission method is as follows.
Due to its low signal power density characteristics, it has a feature that it does not easily interfere with other wireless systems, and is expected as a technology capable of overlaying a frequency band used by existing wireless systems. In addition, because of the wide bandwidth, Personal Area Net
work: PAN), it is regarded as a promising ultra-high-speed wireless transmission technology at the 100 Mbps level.

The receiving means 50 is a receiving device capable of receiving the radio wave transmitted from the transmitting means 30 and decoding the bit string. The signal received by the receiving means 50 is input to the determining means 60. The judging means 60 receives the information of the control channel transmission timing from the transmission suspending means 20 and the bit string information of the control channel transmitted from the control channel generating means 40, and receives the information in the transmission stop slot set by the transmission suspending means 20. A comparison is made as to whether or not the bit sequence obtained is from the control channel generating means 40 of the own station. As a result of the comparison, if they match, there is no problem. However, if they do not match, it means that the control channel has been transmitted from another station at the same transmission timing. Issue a change instruction.

The selection changing means 70 of this embodiment includes a unique number generating means 71, a unique number extracting means 72, and a priority determining means 7.
3 is comprised.

The unique number generating means 71 generates a unique number (identification code) capable of identifying each control station, and sends the uniquely determined unique number to the control channel generating means 40 as a bit string. Insert into channel. The unique number extracting means 72 receives the bit string from the receiving means 50 and extracts the unique number contained therein when the change instruction is issued from the determining means 60. The priority determining unit 73 receives the unique numbers from the unique number generating unit 71 and the unique number extracting unit 72, and calculates the priority between them according to a predetermined calculation procedure. The output of the priority order judging means 73 is used as a control signal of the selector MUX in the transmission timing setting means 10 to switch between different transmission timings.

It is needless to say that it is preferable to make a priority order determination, but it is not always essential. In some cases, a change instruction from the determination means 60 is directly transmitted to the transmission timing setting means 10. It is also possible to use the selection changing means.

FIG. 2 shows a flowchart of a control channel transmission process by the control station device of the present embodiment. 3 and 4 schematically show control channels transmitted by the time division multiplexing method for explanation. In both figures, (A) shows the control channel transmission timing of the own station, and (B) shows the control channel transmission timing. It shows the control channel transmission timing of another station. It is assumed that both the own station and the other stations have the apparatus shown in FIG.

At the start of transmission in step S1, the transmission timing setting means 10 first selects the first transmission timing. In the case of this example, as shown in FIG. 3, the first transmission timing is such that the control channel is transmitted in the first, third, seventh, fifteenth, and fortieth time slots, and happens to coincide with the own station (A). It is assumed that the same timing is set with another station (B). When transmission is started, the transmission in a predetermined time slot is stopped by the transmission temporary stop means 20 in step S2. The transmission stop slot is randomly determined by each station. In this example,
As shown in FIG. 3, the transmission stop slot of the own station (A) is set to time slot 7 (dotted line), and the transmission stop slot of the other station (B) is set to time slot 15 (dotted line).

In this case, the own station (A) and the other station (B) have the same first transmission timing.
In 3 and 40, the radio waves of the two collide with each other and correct transmission cannot be performed. On the other hand, in the time slot 7, the own station (A) stops transmitting, and in the time slot 15, the other station (B) stops transmitting. Channel can be received. Therefore, in steps S3 and S4, the determination means 60 determines that the own station (A)
It monitors whether a control channel that is not the one received is received. The judging means 60 obtains the information of the transmission stop slot and the control channel from the transmission temporary stop means 20 and the control channel generating means 40, and confirms that the control channel of the own station (A) is not transmitted in the transmission stop slot 7. Since the control channel is known, it can be determined whether or not the control channel received during this time belongs to another station (B).

If a control channel other than the control channel of the own station (A) has been received in step S4, the process proceeds to step S4.
In step 5, the unique number extracting means 72 extracts the unique number included in the reception control channel. Thereby, another station (B) transmitting the control channel at the same transmission timing
Exists, and the unique number of the other station (B). When the unique number of the other station (B) is determined, the priority order determining means 73 calculates the priority of the own station (A) and the other station (B) based on the unique number in step S6. As the evaluation function, for example, the bit string of the unique number may be an integer represented by a binary number, and the larger the integer, the higher the priority.

If it is determined in step S6 that the own station (A) has a higher priority, the own station (A) has the first priority.
Maintain the transmission timing as it is. On the other hand, if it is determined that the priority is low, a change signal is output from the priority determining means 73 in step S7, and the selection switching of the selector MUX of the transmission timing setting means 10 is performed. The timing is changed to the transmission timing or the third transmission timing.

On the other hand, the same process is performed in the other station (B), and the control channel of the own station (A) is received in the time slot 15 which is the transmission stop slot of the other station (B).
As a result of the determination of the priority order from now on, the other station (B) determines that the own station has a lower priority.
Is changed to the second transmission timing. Therefore, as shown in FIG.
The other station (B) switches to the second transmission timing while maintaining the transmission timing, thereby avoiding collision.

[0026]

According to the present invention, it is possible to solve the transmission timing collision in the time division multiplexing system, which greatly contributes to the shift of radio communication to UWB. According to the present invention, particularly, from the viewpoint of catching the control channel on the terminal station side, acquisition is tried first at the first transmission timing, and if acquisition is not possible, acquisition is attempted at the second transmission timing. ..,..., Etc., the control channel can be reliably grasped by following the predetermined transmission timing in order.

In the prior art, a method of transmitting a control channel with a random delay when timing overlaps is the mainstream, but from the viewpoint of a terminal station, there is no way to capture if a random delay occurs. Become. In addition, if there is no collision avoidance control, the control channel keeps hitting, and no acquisition can be performed.
On the other hand, according to the present invention, it is possible to achieve both control avoidance control of the control channel on the transmission side and reliable and high-speed capture of the control channel on the reception side by performing regular change control of the transmission timing. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a control station device according to the present invention.

FIG. 2 is a flowchart illustrating an example of a control channel transmission method according to the present invention.

FIG. 3 is an explanatory diagram showing a time slot in a case where transmission timings of control channels overlap between a local station (A) and another station (B).

FIG. 4 is an explanatory diagram showing a time slot after a collision of control channel transmission timing is avoided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transmission timing setting means 20 Transmission temporary stop means 30 Transmission means 40 Control channel generation means 50 Reception means 60 Judgment means 70 Selection change means 71 Unique number generation means 72 Unique number extraction means 73 Priority judgment means

Claims (5)

[Claims] 1. A control channel transmission method for wireless communication in which a control channel is transmitted by a time division multiplexing method, comprising: a transmission stop step of stopping transmission in a predetermined time slot during a control channel transmission timing; A reception confirmation step of confirming whether a control channel is received in the stopped time slot; and a timing change step of changing to another control channel transmission timing when reception of the control channel is confirmed. Control channel transmission method. 2. The method according to claim 1, wherein the timing changing step comprises: when a reception of the control channel is confirmed, identifying an originating station of the control channel; Compare the station priority and maintain the current control channel transmission timing if the own station is higher priority, and change to another control channel transmission timing if the own station is lower priority To do,
A control channel transmission method, comprising: 3. Transmission timing setting means for selecting and setting one of a plurality of different control channel transmission timings, and stopping transmission of any one of the time slots in the control channel transmission timing selected by the transmission timing setting means. Transmission pause means for setting a slot, control channel generation means for generating a control channel of the own station, control by the control channel generation means at control channel transmission timing according to the transmission timing setting means and the transmission suspension means Transmitting means for transmitting a channel; receiving means for receiving a control channel; and when the control channel is received by the receiving means in a transmission stop slot by the transmission suspending means, the received control channel is controlled by the control means. Determine whether the channel is a control channel by the channel generation means. And determination means, the result of the determination by the determination unit, when not a control channel of the own station, control station anda selection change means for selecting a different control channel transmission timing to the transmission timing setting unit. 4. The control station device according to claim 3, wherein the selection changing unit generates a unique number of the own station, sends the unique number to a control channel generating unit, and includes the unique number in a control channel. When the determination result of the means is not the control channel of the own station, a unique number extracting means for extracting a unique number from the control channel received by the receiving means, and the extracted unique number and the unique number of the own station. And a priority determining unit that determines a priority by comparing the transmission timing of the own station and, when the priority of the own station is lower, causes the transmission timing setting unit to select another control channel transmission timing. 5. The control station device according to claim 3, wherein the transmitting means performs ultra wideband communication.