JP3432046B2 - Wireless communication system and main device thereof - 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 communication system using a frequency hopping system and its main device .

[0002]

2. Description of the Related Art Recently, among digital wireless communication systems, spread spectrum communication has attracted particular attention. This spread spectrum communication is known as a technique that spreads information to be transmitted in a wide band to enhance the interference removal capability and to provide excellent confidentiality. Spread spectrum communication systems are roughly classified into frequency hopping (FH system) and direct spread (DS system). The frequency hopping method is
This is a method in which a certain band is divided into a plurality of bands and the frequency is changed one after another while transmitting 1 bit of data. In order to realize a system for transmitting information between information devices such as computers using this method, the device becomes large.

Therefore, in the currently realized system,
Instead of changing the frequency one bit after another in one bit of data,
A method is adopted in which the frequency is changed for every tens of bits of data and transmitted. The order in which the frequency is changed by the frequency hopping method is called a hopping pattern (hereinafter abbreviated as HP).

When configuring a plurality of cells, it is necessary to select HP so that adjacent cells do not use the same frequency at the same time. Also, if there is an interfering wave and its effect cannot be eliminated, it is necessary to select a different HP.

[0005]

However, in the FH method, the HP is changed by providing a method of storing the HP in a ROM or the like in the apparatus and a circuit for generating the HP. Therefore, in order to be able to change to another HP when there is an interfering wave, for example, a large capacity ROM is required. In Japan, the frequency that can be used for spread spectrum communication is 2.484 GHz ± 13 MH
Since it is z, frequency channels are set every 1 MHz and 2
Assuming a system that performs FH using 20 frequency channels from 6 frequency channels, the total number of this combination is a factorial of the number of frequency channels, and it is not realistic to store all of them in ROM, and the HP generation circuit However, since it becomes quite complicated, there is a problem that the communication device cannot be downsized.

[0006] The present invention has been made to solve the above problems, and provides a wireless communication system in which the disabling of a call due to an interfering wave is eliminated by making the hopping pattern variable and the confidentiality is improved. With the goal.

It is another object of the present invention to provide a wireless communication system and its main device that can change the hopping pattern all at once even when there is a terminal in communication.

[0008]

In order to achieve the above object, a wireless communication system of the present invention has the following configuration.

That is, in a wireless communication system composed of a main device and a plurality of terminal devices and performing communication using a frequency hopping system, a selecting means for selecting a frequency pattern for frequency hopping and the selecting means. And transmitting means for transmitting the frequency hopping pattern to a plurality of terminal devices, dividing one hopping cycle into a plurality of time slots, and transmitting in each time slot.
In line frame advance put data indicating hopping period what round, when changing the frequency hopping pattern used in the system, along with a new frequency hopping pattern, the frequency at what round hopping period of time slots Whether to change the hopping pattern is transmitted.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a system configuration of a wireless communication system in the embodiment. In the figure, 1 is a main device, and 2-A and 2-B are terminal devices, which function as a wireless telephone. 3-A, 3-B, 3
-C, 3-D, 3-E are terminal devices, which function by connecting to a data terminal.

FIG. 2 is a flowchart for changing the hopping pattern (HP) using the logical control channel. FIG. 3 is a flowchart showing the “ACK confirmation procedure” of FIG. The details of the processing procedure will be described later.

FIG. 4 is a conceptual diagram showing how to hop frequencies.

In this system, for example, as shown in FIG. 5, one frame of communication data has a length of 5 ms.
Since the frequency channel is hopped for each frame, the length of one cycle of one hopping pattern is 100.
ms.

In FIG. 4, different hopping patterns are shown with different symbols, and a pattern is used in each frame such that the same frequency is not used at the same time. This makes it possible to prevent data errors and the like from occurring. Further, when accommodating a plurality of terminal devices, different hopping patterns are used for the respective terminal devices in order to prevent interference between the terminal devices. With this method, a system having a multi-cell configuration can be realized and a wide service area can be obtained.

FIGS. 5 to 10 are diagrams showing the frame structures of radio frames used in this system. In this system, two different frames are used: a "main device-wireless dedicated telephone communication frame" (hereinafter abbreviated as PCF) and a "wireless dedicated telephone communication frame" (hereinafter abbreviated as PPF).

The internal data of each frame will be described below.

In the PCF shown in FIG. 5, FSYN is a synchronizing signal, LCCH-T is a logical control channel sent from the main unit to the wireless dedicated telephone, LCCH-R is a logical control channel sent from the wireless dedicated telephone to the main unit, and T1. , T
2, T3, T4 are voice channels sent to four different wireless dedicated telephones, R1, R2, R3, R4 are voice channels transmitted from four different wireless dedicated telephones, and GT is a guard time. Further, F1 and F3 are frequency channels used when wirelessly transmitting this frame, and indicate that the frequency channel is changed for each frame.

In the PPF shown in FIG. 6, FSYN is a synchronizing signal, LCCH-T is a logical control channel sent from the main unit to the wireless dedicated telephone, LCCH-R is a logical control channel sent from the wireless dedicated telephone to the main unit, and T1. , T
2 and T3 are voice channels sent to three different wireless dedicated telephones, R1, R2 and R3 are voice channels transmitted from three different wireless dedicated telephones, and GT is a guard time.

Further, F1, F3, F5 and F7 are frequency channels used when transmitting this frame wirelessly,
Unlike the PCF, after receiving the logical control information LCCH-T from the main unit on the frequency channel F1, the frequency channel is switched to F5 reserved for communication between wireless dedicated telephones to perform communication between wireless dedicated telephones. After that, the procedure of switching the frequency channel to F3, receiving the logical control information from the main device, and further switching the frequency channel to F7, which is secured for communication between the wireless dedicated telephones, is performed until the communication between the wireless dedicated telephones is completed. repeat.

In the sync signal FSYN frame and LCCH-T frame shown in FIG. 7, R is a carrier sense time for confirming that the previous frame has ended and whether another wireless terminal is emitting radio waves, PR is a 62-bit preamble, SYN a frame synchronizing signal of 31 bits, ID is the calling signal 63 bits, FI in channel type signal of 2 bits, distinguishing signals P C F · PPF,
TS indicates time slot information, and NF indicates frequency information of the next frame. UW indicates a unique word including a sub ID, LCCH indicates logical control information, and GT indicates guard time. Each number in the figure indicates the number of bits of each signal.

The logical control channel LCCH-R shown in FIG.
The frame is a logical control channel sent from the wireless-only telephone to the main unit, and its content is similar to that of the frame shown in FIG.

The voice channels Tn and R are shown in FIGS. 9 and 10.
The structure of n is shown. Here, the structure of T1, T2, T3, T4
Adult, and, R1, R2, R3, R4 configuration, respectively, are common, and displays the Tn collectively transmitting voice channel reception are indicated collectively by Rn voice channel.

FIG. 11 is a diagram showing a LCCH hopping pattern transmission format in the embodiment.
The details of the format will be described later.

The operation of changing the hopping pattern according to the embodiment having the above configuration will be described below.

It is assumed that the present system selects and communicates with the first hopping pattern shown in FIG. In addition, in this system, when exchanging LCCHs, only LCCHs are assigned to each terminal device by time slot (hereinafter abbreviated as TS) in order to prevent occurrence of collision. For example, in FIG.
In the case of, the terminal device 1 is connected to TS1 and the terminal device 2 is connected to TS2.
Send LCCH for. LC is assigned to a specific TS
With CH alone, the call continues hopping frame by frame until the call ends.

Then, it becomes necessary to change the HP in order to improve the confidentiality, or some frequencies become unusable due to the interfering wave and the HP used in the system is replaced with another HP.
When it becomes necessary to change to P, the HP of the system is changed according to the changing procedure shown in FIG.

The operation will be described below with reference to the flow chart shown in FIG. This changing procedure includes the following procedure.

(1) Generation of new HP (step S10)
1) (2) Notification of new HP (step S102) (3) Confirmation of reception of new HP (step S103) (4) Instruct timing for switching HP (step S102)
104) (5) HP switch timing reception confirmation (step S1
05) In each procedure, (1-1) and (1-2) mean that there are a plurality of ways in the procedure,
Since the whole procedure is a combination of all of these, there are a plurality of procedures. (1) Generation of a new HP When it becomes necessary to change the HP, the main device first uses the specific channels or the random method from the frequency channels excluding the frequency channel in which the main device cannot communicate to the next HP.
To decide.

(1-1) When the HP is changed due to the need for confidentiality, the pattern currently in use is shifted by one on the frequency channel axis shown in FIG.

(1-2) When there is a frequency channel in which a call cannot be made, a channel for which a call cannot be made is randomly selected from frequency channels that are currently unused. (2) Notification of new HP (2-1) When notifying all HPs, when a new HP is determined, the wireless terminal is notified of the new HP using LCCH-T shown in FIG. FIG. 11 shows the contents of the LCCH at this time. There is a command to change the HP at the head, and subsequently, when the time slot is 1 (TS1), frequency channel numbers are entered in the order of frequency hopping. For example, the command followed by 14, 16, 18, 2
If 0, ... Are given as a 5-bit binary number, frequency channel 14 is used in TS1 and frequency channel 1 is used in TS2.
It means that 6 is used.

(2-2) When only a changed part is notified in HP, when a new HP is determined, L shown in FIG.
The CHP-T is used to notify the terminal device of the new HP.
The time slot number to be changed and the frequency channel number assigned to the time slot number are notified following the command indicating the HP change. For example, if the command is followed by 4, 23, it means that the time slot 4 (TS4) is changed to the frequency channel 23. (3) Confirmation of reception of new HP When the new HP is notified by the above-mentioned processing, the terminal device returns an ACK signal indicating the reception to the main device using LCCH-R. This LCCH is assigned by a time slot, but unfortunately, when the frequency channel of the time slot in which the LCCH is exchanged becomes unusable due to an interfering wave, the terminal device is notified of the new HP, and the terminal device also notifies It is possible that the main device cannot or cannot receive the ACK signal. Since it is not always possible to reliably exchange ACK signals in this way,
If the CK signal is not returned or there is a response from the terminal device that cannot be returned, the whole process will be interrupted.

Therefore, in the embodiment, the ACK confirmation procedure shown in FIG. 3 is executed. First, ACK from each terminal
The signal is confirmed (step S201), and if there is a terminal device that has not returned the ACK signal, HP is transmitted again to the terminal device (step S202). Then, the number of times of retransmission is counted, and it is checked whether or not the number of times of retransmission is less than or equal to a predetermined value (step S203).
Here, if it is less than or equal to the predetermined value, the process returns to step S201, but if it exceeds the predetermined value, the terminal device that has not returned the ACK signal is ignored and the process proceeds.
That is, the time slot assigned to the terminal device is regarded as "vacant" (step S204). Also, ACK
The terminal device which has not returned the signal performs the initial registration procedure again and controls so as to allocate a time slot for exchanging a new LCCH. (4) Instructing the timing to switch the HP Next, each terminal device is notified when the HP is changed.
That is, the switching time is notified after the command indicating the HP switching time.

(4-1) The number of time slots indicating the number of time slots to be switched after is notified. In this case, since the time slot for exchanging the LCCH is different for each terminal device, the main device needs to notify each terminal device in consideration of this point.

(4-2) Data indicating the hopping cycle of the round is put in NF in the FSYN frame shown in FIG. 7, and the time slot of the round to change the HP is notified. . (5) HP switching timing reception confirmation Whether or not each terminal device has received the switching time is confirmed by an ACK signal. This procedure is the same as the above (3), but the value of the number of retransmissions does not have to be the same as that at the time of HP notification.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. It goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0037]

As described above, according to the present invention,
In a frequency hopping type wireless communication system, a hopping pattern can be made variable, and a frequency channel incapable of making a call due to an interfering wave can be avoided, and the callability can be improved by appropriately changing the hopping pattern.

Further, the hopping pattern can be changed all at once even if there is a terminal device during a call.

[0039]

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of a wireless communication system according to an embodiment.

FIG. 2 is a flowchart showing a procedure for changing a hopping pattern by a logical control channel.

FIG. 3 is a flowchart showing an “ACK confirmation procedure” shown in FIG.

FIG. 4 is a diagram showing frequencies for performing frequency hopping and an order of hopping.

FIG. 5 is a diagram showing a communication frame between a main device and a terminal device.

FIG. 6 is a diagram showing a communication frame between terminal devices.

FIG. 7 is a diagram showing an FSYN frame and an LCCH-T frame structure.

FIG. 8 is a diagram showing an LCCH-R frame structure.

FIG. 9 is a diagram showing a Tn frame structure.

FIG. 10 is a diagram showing an Rn frame structure.

FIG. 11 is a diagram showing a hopping pattern transmission format by LCCH.

[Explanation of symbols]

1 main device 2 Wireless telephone 3 data terminals

Claims (3)

(57) [Claims] 1. A wireless communication system comprising a main device and a plurality of terminal devices and performing communication using a frequency hopping method, a selecting means for selecting a frequency pattern for frequency hopping, and a selecting means for selecting by the selecting means. the frequency hopping pattern and a transmitting means for transmitting to a plurality of terminal devices, by dividing one hopping period into a plurality of time slots, each
In the radio frame transmitted in the time slot keep putting data indicating hopping period what round, when changing the frequency hopping pattern used in the system, along with a new frequency hopping pattern,
A wireless communication system, characterized in that the frequency hopping pattern is changed in a time slot of a hopping cycle . 2. In a main unit of a wireless communication system that communicates with a plurality of terminal devices by using a frequency hopping method, a selecting means for selecting a hopping pattern, and a hopping pattern selected by the selecting means,
And a notifying means for notifying each of the plurality of terminal devices, by dividing one hopping period into a plurality of time slots, each
In the radio frame transmitted in the time slot keep putting data indicating hopping period what round, the notification unit, when changing the frequency hopping pattern used in the system, along with a new frequency hopping pattern, what A main unit of a wireless communication system, which notifies whether to change a frequency hopping pattern in a time slot of a hopping cycle of a round. 3. A main device of a wireless communication system for communicating with a plurality of terminal devices using a frequency hopping method, wherein a hopping pattern is a plurality of timeslots assigned to each of the plurality of terminal devices. and notifying means for notifying each of the terminal devices, the plurality of terminal devices, processing is regarded as idle time slot that has been allocated to the terminal device does not come returns a response
A main unit of a wireless communication system, comprising: a setting unit configured to make a progress .