JPH08149132A - Network system and its communication equipment and communication method - Google Patents

Abstract

PURPOSE: To provide a network system, its communication equipment and communication method in which the effect of noise in existence in the environment of the receiver side is excluded. CONSTITUTION: A CPU 107 at the transmitter side uses a radio section 102 to check a radio wave environment and to select candidate of a channel available of communication and allows the radio section 102 to report a frame including candidate channel information generated by a communication controller 104 to a communication opposite party. A CPU 107 of a receiver side uses a radio section 102 to check the radio wave state of the candidate channel informed by the transmitter side and selects a channel used for communication among candidate channels and allows the radio section 102 to return a frame including selected channel information generated by a communication controller 104 to the transmitter side. Then the communication is made by using the channel selected by the receiver side. Thus, frequent occurrence of a communication error is prevented and the repetition of re-transmission processing is prevented to prevent deteriorated throughput of the LAN system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system and a communication device and a communication method thereof, and more particularly, to a network system such as a computer network for mutually connecting information devices such as computers and a communication device and a communication method thereof. .

[0002]

2. Description of the Related Art Spread spectrum (hereinafter referred to as "SS") wireless communication of a low-frequency frequency hopping (hereinafter referred to as "SHF") system is performed by decomposing data into a plurality of sets of frequency channels to perform communication. Even if there is a noise or other obstacle, it has the advantage that it is not easily affected by it.
When performing communication by this method, it is necessary to synchronously select the same frequency channel for both transmission and reception, and there are the following selection methods for realizing this.

(1) At the beginning of communication, the transmitting side notifies the pattern of the channel to be used (the order of the hopped channels). (2) The transmitting side specifies the channel for transmitting the next data, that is, A channel for transmitting the Nth data is designated during the transmission of the N-1th data. Normally, the channel used at the beginning of transmission is fixed.

[0004]

However, the above-mentioned conventional example has the following problems.

That is, the channel used for communication is selected by the transmitting side, and the environments of the transmitting side and the receiving side may be different, but the environment of the receiving side cannot be taken into consideration. Therefore, in the vicinity of the specified channel frequency, even if there is no noise in the environment on the transmitting side, there may be strong noise in the environment on the receiving side.In such a case, communication errors occur frequently. , The retransmission process will be repeated, and LA
N There is a problem that the throughput of the system decreases.

The present invention is intended to solve the above-mentioned problems, and its purpose is as follows. It is an object of the present invention to provide a network system capable of eliminating the influence of noise existing in the environment on the receiving side, a communication device and a communication method thereof.

[0007]

[Means for Solving the Problems] and

The present invention has the following structure as one means for achieving the above object.

A network system according to the present invention is
A network system for connecting information devices to each other by wireless communication, wherein the transmitting side selects a candidate channel that can be used for communication according to the radio environment,
The receiving side is provided with a communication means for notifying the communication partner of the candidate channel information, and the receiving side selects the channel to be used for communication according to the radio wave condition of the candidate channel notified from the transmitting side, and the selecting means. A communication means for notifying the transmitting side of the channel information is provided, and communication is performed using the channel selected by the receiving side.

Further, the communication device according to the present invention is a communication device used in a network system for mutually connecting information devices by wireless communication, and has a monitoring means for monitoring the radio wave environment, and a monitoring of the monitoring means. The setting means includes a selecting means for selecting a channel that can be used for communication according to a result and a communication means for performing communication by the channel selected by the selecting means, and when operating as a transmitting side, the setting means displays the monitoring result. Accordingly, the communication means selects a candidate for a channel, the communication means notifies the communication partner of the candidate channel, and when the communication means operates as a receiving side, the selecting means responds to the radio wave condition of the notified candidate channel. The channel used for communication is selected, the communication means notifies the selected channel to the communication partner, and the channel selected by the receiving side is selected. And performing communication by use.

Further, the communication method according to the present invention is a communication method for a network system in which information devices are mutually connected by wireless communication, and a channel candidate that can be used for communication is selected according to the radio environment of the transmitting side. A first selecting step, a first notifying step of notifying the communication partner of the candidate channel information, and a second channel selecting channel to be used for communication according to the radio wave condition of the candidate channel notified from the transmitting side. Of the selected channel information, a second notification step of notifying the selected channel information to the transmitting side, and a communication step of performing communication using the channel selected by the receiving side.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0012]

[First Embodiment] FIG. 1 is a block diagram showing a configuration example of a communication device according to one embodiment of the present invention, which is an adapter type device which is used by being connected to an interface or the like of a terminal.

In the figure, 101 is an antenna, 102 is a radio unit including a modulation / demodulation unit, and 103 is a bit synchronization circuit (DPL).
L), 104 is a communication controller that assembles / disassembles packets and controls communication, and 105 controls communication with the terminal 109.
LAN controller, 106 is an error correction code encoder / decoder,
Reference numeral 108 is a memory including ROM and RAM, and 107 is a CPU. The CPU 107 controls the entire apparatus via the CPU bus 107a according to a program stored in advance in the memory 108. Further, 109 is a terminal provided with a LAN interface, for example, information equipment such as a computer, a reader, a printer, or the like. , MO and other large-capacity storage devices. Further, it may be a digital copying machine having an interface with an external device.

FIG. 2 is a flow chart showing an example of an operation procedure at the time of transmission of this embodiment, which is executed by the CPU 107.

First, in step S200, a state of waiting for a packet from the terminal 109 is entered, and when the LAN controller 105 receives a packet from the terminal 109 in step S201, step S2
In 02, the radio unit 102 checks the radio wave environment, and in step S203 it is determined whether or not there is a usable channel (frequency). If there is no available channel, the communication with the terminal 109 is disconnected in step S210, and the process returns to step S201.

Step if there are channels available
Proceed to S204 and assemble with the communication controller 104, as shown in FIG.
The call setting request frame as an example is transmitted from the wireless unit 102 to the other party via the control channel. The usable channel information confirmed in step S202 is also included in this frame as a candidate channel.

Then, in step S205, the system waits for a response from the other party, and in step S206, it is determined whether or not there is a response from the other party within a predetermined time. If there is no response within the predetermined time, it is determined that the other party is already communicating or has not been activated, disconnects the communication with the terminal 109 in step S210, and then returns to step S201.

If there is a response from the other party within a predetermined time, the communication controller 104 confirms the communication channel designation in the response frame in step S207, and determines in step S208 whether transmission is possible. That is, when the communication channel is not specified in the response frame, it is determined that this response frame represents the call acceptance rejection, and in step S210
After disconnecting the communication with the terminal 109 by the LAN controller 105, the process returns to step S201. If the communication channel has been designated, it is determined that transmission is possible, the process proceeds to step S209, the designated channel is set in the wireless unit 102, and communication is started.

FIG. 4 is a flow chart showing an example of the operation procedure at the time of reception in this embodiment, which is executed by the CPU 107.

First, in step S300, the control channel enters a reception waiting state, and in step S301, when the communication controller 104 receives a call setting request frame, step S30
In step 2, the candidate channel is obtained from the frame received by the communication controller 104, the status of the candidate channel is checked by the wireless unit 102 in step S303, and it is determined in step S304 whether there is an available channel among the candidate channels. To do. If no candidate channel is available, step S311
Then, the call acceptance refusal frame (frame without communication channel designation) created by the communication controller 104 is transmitted to the wireless unit 10.
After returning to the other party by 2, return to step S300.

If there is a candidate channel that can be used, in step S305, the LAN controller 105 starts the arc setting with the terminal 109, and in step S306, it is determined whether or not the call with the terminal 109 has been set, and the call is established. If cannot be set, the wireless unit 102 returns the call acceptance refusal frame created by the communication controller 104 to the other party in step S311, and then returns to step S300. If a call with terminal 109 is set up,
In step S307, the wireless unit 102 returns the call acceptance frame created by the communication controller 104 to the other party. This frame contains information designating the communication channel selected from the candidate channels.

Then, the channel designated in step S308 is set in the radio section 102 to enter the reception standby state,
At 309, it is determined whether or not there is a reception from the other party within a predetermined time. If there is no response within the specified time, the other party
After determining that communication has been stopped or there is an abnormality, the LAN controller 105 disconnects the call to the terminal 109 in step S312, and then the process returns to step S300. If there is reception from the other party within a predetermined time, the communication controller 104 starts the data frame reception process in step S310.

As described above, according to this embodiment,
The sender can specify multiple channels (frequency) candidates to use for communication, and the receiver can select a communication channel according to the radio environment from the candidate channels, so strong noise existing in the environment of the receiver, etc. The influence of is eliminated as much as possible, frequent occurrence of communication errors is prevented, and retransmission processing is prevented from being repeated, so that it is possible to prevent the throughput of the LAN system from decreasing.

[0024]

Second Embodiment A communication device according to the second embodiment of the present invention will be described below. It should be noted that in the second embodiment, substantially the same configurations as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment relates to a system for transmitting a plurality of frames obtained by decomposing one packet through different channels or two or more channels.

FIG. 5 is a flow chart showing an example of an operation procedure at the time of transmission of this embodiment, which is executed by the CPU 107.

In step S201, a packet is sent from the terminal 109 to the LAN
When the controller 105 receives, the packet received by the communication controller 104 is decomposed into frames of a predetermined length in step S501, and the number of frames decomposed in step S502 is counted.

Then, as in the first embodiment, step S20
In step 2, check the radio wave environment with the wireless unit 102, and then
Whether or not there is a usable channel (frequency) in S203 is determined. If there is no available channel, the communication with the terminal 109 is disconnected in step S210, and the process returns to step S201. In a system in which a plurality of frames obtained by decomposing one packet are all transmitted through different channels, it is determined that there is a usable channel in step S203 when the following conditions are satisfied. Number of empty channels ≥ Total number of frames

Further, in a system in which a plurality of frames obtained by decomposing one packet are transmitted through n or more channels, it is determined that there is a usable channel in step S203 when the following conditions are satisfied. Empty channel ≧ n

Step if there are channels available
Proceed to S503 and assemble with the communication controller 104, as shown in FIG.
The call setting request frame as an example is transmitted from the wireless unit 102 to the other party via the control channel. This frame includes the total number of frames counted in step S502 and the candidate channel information confirmed in step S202. Since the procedure after step S205 is the same as that of the first embodiment, its details are omitted.

On the other hand, the receiving side which has received the call setup request frame shown in FIG. 6 determines whether the candidate channel can be used as in the first embodiment. Returns a call acceptance frame indicating. This frame includes designated channel information that designates the relationship between the frame number and the communication channel.

As described above, according to this embodiment,
Even in a system in which a plurality of frames obtained by decomposing one packet are transmitted through different channels or two or more channels, the same effect as that of the first embodiment can be obtained.

The present invention may be applied to either a system composed of a plurality of devices or an apparatus composed of a single device.

Needless to say, the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0035]

As described above, according to the present invention,
It is possible to provide a network system that eliminates the influence of noise existing in the environment on the receiving side, a communication device and a communication method therefor, for example, to prevent frequent occurrence of communication errors and prevent repeated retransmission processing, and thus a LAN system. Can be prevented from decreasing.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing an example of an operation procedure at the time of transmission of this embodiment,

FIG. 3 is a diagram showing a configuration example of a call setup request frame;

FIG. 4 is a flowchart showing an example of an operation procedure at the time of reception in the present embodiment,

FIG. 5 is a flowchart showing an example of an operation procedure at the time of transmission according to the second embodiment of the present invention,

FIG. 6 is a diagram showing a configuration example of a call setup request frame;

FIG. 7 is a diagram showing a configuration example of a call reception frame.

[Explanation of codes] 101 Antenna 102 Radio part 103 Bit synchronization circuit (DPLL) 104 Communication controller 105 LAN controller 106 Code / decoder 108 Memory 107 CPU 109 Terminal

Claims (5)

[Claims] 1. A network system for connecting information devices to each other by wireless communication, wherein a transmitting side selects a channel candidate usable for communication according to its radio wave environment, and the candidate channel information. Communication means for notifying the other party of communication, the receiving side selects the channel to be used for communication according to the radio wave condition of the candidate channel notified from the transmitting side, and the selected channel information. A network system comprising: a communication unit for notifying to a transmitting side, and performing communication using a channel selected by the receiving side. 2. A communication device used in a network system for mutually connecting information devices by wireless communication, the monitoring device monitoring the radio wave environment, and usable for communication depending on the monitoring result of the monitoring device. A channel that can be used for communication according to the monitoring result, when operating as a transmitting side, the setting means includes a selecting means for selecting a different channel, and a communication means for performing communication by the channel selected by the selecting means. Select the candidate of
When the communication means notifies the communication partner of the candidate channel and operates as a receiving side, the selection means selects a channel to be used for communication according to the radio wave condition of the notified candidate channel, and the communication means A communication device characterized by notifying a communication partner of a selected channel and performing communication using the channel selected by the receiving side. 3. The communication device according to claim 1, wherein the communication unit performs spread spectrum communication. 4. The communication means performs spread spectrum communication of a frequency hopping system.
Alternatively, the communication device according to claim 2. 5. A communication method of a network system for mutually connecting information devices by wireless communication, comprising a first selecting step of selecting a channel candidate usable for communication according to a radio environment of a transmitting side, A first notification step of notifying the communication partner of the candidate channel information, a second selection step of selecting a channel to be used for communication according to the radio wave condition of the candidate channel notified from the transmitting side, and the selected A communication method comprising: a second notifying step of notifying channel information to the transmitting side, and a communication step of performing communication using the channel selected by the receiving side.