JP2008177671A - Wireless lan transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid such a state that a communication error occurs when systems of a plurality of signals use the same communication frequency when a wireless LAN transmission device which transmits the plurality of signals simultaneously and independently of each other makes a search to be switched to a channel for a better communication state. <P>SOLUTION: When a channel where the communication state of one system is better is searched for (S1), the transmission of another system is stopped, channels C2 to C13 are searched for the one system (S2) to find a channel where the communication state is better (S3), and the transmission of the one system is carried out (S4). Then a search is performed from a channel whose frequency is most apart from that of the channel that the one system uses to a closer channel (S6) to find a channel where the communication state of the other system is the best (S7), and the transmission of the other system is performed over the found channel (S8). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

In the present invention, for example, when a voice signal is transmitted cordlessly and output from a speaker, a channel having a better communication state is selected from a plurality of usable channels, and the voice is used by using the channel. The present invention relates to a wireless LAN transmission device that transmits signals.
In particular, in the present invention, when two or more communication systems are simultaneously transmitted using a plurality of channels, a channel having a better communication state can be selected by arbitrarily selecting from a plurality of usable channels. The present invention relates to a technique for avoiding an interference failure (error) that tends to occur when finding an error.

For example, it is known to simultaneously transmit an audio signal to a speaker side and a signal related to a computer device using the same wireless LAN transmission device, for example, cordlessly.
That is, it is known that two or more systems of signals are simultaneously transmitted using a single wireless LAN transmission device.

In the transmission of such a signal, the number of usable channels is limited, and a channel to be used is arbitrarily selected from the limited channels, and the signal system is assigned to the selected channel and used. Yes.
However, when a finite number of channels, that is, a channel arbitrarily selected from a plurality of usable channels is used, the arbitrarily selected channel does not always transmit a signal in a good communication state. Absent.

Therefore, when signal transmission is performed using a wireless LAN, an arbitrary channel is first selected from a plurality of usable channels, and then a channel with a better communication state is sequentially searched for the best. Searching for and switching between channels is used.
The following documents are known as techniques for sequentially searching for a channel having a better communication state from a plurality of usable channels and finally finding and using the channel having the best communication state. .

JP-A-8-149113

In the invention disclosed in Japanese Patent Application Laid-Open No. 8-149113, first, priorities are set in advance for a plurality of channels, and the highest priority channel is selected first. Here, if an error occurs using the highest priority channel and the communication state is not good, the priority is lowered in order and the lower channel is selected to transmit a signal that does not cause an error, that is, communication. If a channel is found that is in good condition, that channel is used.
Then, record the number of successful communications by avoiding errors by selecting this channel (accumulate as data), and select the channel with the better communication status when recording the next signal (data). The control is performed so that the best channel is automatically selected in accordance with the above.

By such a series of operations, an error is avoided and a channel to be used is efficiently obtained.
For example, when simultaneously transmitting an audio signal related to a cordless speaker system and a signal related to a computer device using a single wireless LAN, the signal used in the signal transmission of the cordless speaker system and the signal related to the computer device are used. There are cases where channels used for transmission overlap each other and a communication error occurs.

In other words, when two or more system signals are transmitted simultaneously via a single wireless LAN, the signals related to the two or more systems are assigned to arbitrarily selected channels and transmitted. When the frequencies are close to each other, the two or more channels may overlap with each other to cause a communication error and a good communication state may not be obtained.
In particular, in signal transmission by wireless LAN, even if the channel related to the cordless speaker system and the channel related to the signal of the computer device are set so as not to overlap each other at the beginning of the start, When switching to another channel so that the communication state becomes a better state, the two channels may overlap each other and fall into an interference state.

That is, the invention disclosed in Japanese Patent Application Laid-Open No. 8-149113 is effective in obtaining a good communication state when only one signal is transmitted using a wireless LAN, and does not cause a problem.
However, considering that the invention having such contents is adapted to use when transmitting signals of a plurality of systems using a wireless LAN, each signal system is in a better communication state independently of each other. When searching for a channel, a communication error occurs between the multiple signal systems at the time of the search, and it may be impossible to avoid the communication error and the transmission of the signal by the wireless LAN may not be possible. There's a problem.

Therefore, in such a case, a communication error occurs when searching for a channel having a better communication state, and data for channel search after the next time cannot be obtained.
The present invention has been made in view of the above circumstances, and transmits a plurality of signals simultaneously using a single wireless LAN, and assigns a system related to these signals to a channel having a better communication state. Thus, there is provided a wireless LAN transmission device that does not cause a communication error such that communication frequencies overlap and become in a state of interference when searching, so that signal transmission does not go down due to the communication error. Is.

In the present invention, two or more channels are simultaneously transmitted using two or more channels from among a plurality of channels, and one channel is selected as a channel having a better communication state. When switching, the wireless LAN transmission device is configured to switch the remaining channels to channels that do not cause interference with respect to the channels that are selected and switched.
The detailed configuration includes a plurality of channels, two or more signal systems are arbitrarily selected and assigned from the plurality of channels, and mutually independent signals are transmitted simultaneously. In a wireless LAN transmission device configured to switch the channel to a channel with a better communication state,
When one of the channels related to the two or more systems used above is switched to a channel having a better communication state, the channel used in the remaining systems with respect to the newly switched channel along with the switching. If there is interference, switch the channels in use of those remaining systems to another channel that can avoid the interference, and in addition, the channels in use of the remaining systems that have been switched to have a better communication status. This is a wireless LAN transmission device configured to switch to a different channel.

Note that the selection (assignment) of channels for two or more signal systems is specifically performed by arbitrarily selecting and assigning two or more signal systems to a plurality of channels and simultaneously transmitting independent signals. In this case, if one of the two or more signal systems is switched to a channel having a better communication state, the remaining systems are switched in sequence from the channel farthest away from the channel being used. A method is mentioned.
Also, when switching channels for two or more signal systems, specifically, the remaining signals are transmitted to the signal system that performs channel switching first so as to obtain a better communication state. In this way, the system that switches the channel first can search for a communication state with better communication state without interference.

This invention comprises a plurality of channels, and when two or more channels are transmitted using two or more of them, and when each used channel is switched to a channel having a better communication state, By configuring the remaining channels to switch to channels that do not cause interference with the channels that can be switched, communication errors such as the communication frequency of each channel used for signal transmission overlapping each other will cause interference errors. Therefore, the wireless LAN transmission apparatus can be expected to have a good communication state for transmission of each signal.
When searching for a channel related to the transmission of one signal, the search for the channel related to the one signal system is performed between the channels related to the other system by turning off the remaining signal system. Therefore, it is possible to suppress interference as much as possible, and to find the channel with the best communication state in that state.

The present invention will be described in detail based on the best mode for carrying out the invention shown in the drawings. However, the present invention is not limited by this form.
The wireless LAN transmission device 1 uses frequency channels conforming to the IEEE802.11b standard, and has 1 to 14 channels (assuming that they are C1 to C14, and the frequency increases in an equal difference in the order of these channels). Assume that a frequency is assigned.

Note that this is the content of the current standard, and the number of channels may change due to future changes, and thus the frequency between channels where interference occurs may change.
In addition, the difference between the frequency of each channel and the adjacent frequency is also as the current standard content,
The explanation will proceed according to the contents of the standard.

As shown in FIG. 1, the wireless LAN transmission device 1 includes a communication unit 2, a microcomputer 3, a memory 4, a data bus 5, and a communication unit 6, a microcomputer 7, and data on the receiving side. A bus 8 is provided.
The communication unit 2 constitutes a wireless LAN data transmission system together with the communication unit 6. The communication unit 2 includes an antenna (not shown). The data signal related to video / audio from the DVD player 9 and the data signal from the computer A Is transmitted to the communication unit 6.

The microcomputer 3 controls the video / audio data from the DVD player 9 and the data signal from the computer A10 to be transmitted from the communication unit 2 as signals.
The microcomputer 3 further searches for and sets a channel to be used for wireless communication between the communication unit 2 and the communication unit 6 based on the data stored in the memory 4.
Specifically, when C8 is selected as the signal transmission channel of one system, the microcomputer 3 is based on the order of combinations of channels having good communication states stored in the memory 4 or the frequencies of the channels C1 to C14. C1 is determined as the channel with the largest frequency difference and the least interference.

The memory 4 stores a search order for searching for a channel having a better communication state when a data signal is transmitted from the communication unit 2 to the communication unit 6.
As described above, when two or more data signals are sent from the communication unit 2 to the communication unit 6, the memory 4 is a combination or failure between channels that are likely to have a poor communication state between two or more corresponding channels. The order of difficult combinations is stored.

The data bus 5 is for sending data signals related to video / audio from the DVD player 9 and data signals from the computer A 10 to the communication unit 2.
The DVD player 9 reproduces a DVD recording medium and outputs video and audio data as signals, and the computer A10 outputs a result (data) of the calculation as a signal after performing a desired calculation. To do.

The communication unit 6 includes an antenna (not shown), and receives a data signal related to video / audio from the DVD player 9 from the communication unit 2 and a data signal from the computer A.
In addition, when the microcomputer 7 determines that the communication state of the reception is defective in the reception, the communication unit 6 receives the control signal from the microcomputer 7 and the communication state of the signal through the currently used channel is The fact that it is not good is sent to the communication unit 2.

The microcomputer 7 controls the functions of the video / audio output means 11 and the computer B12 in addition to the above-described determination / response of the reception state.
The video / audio output means 11 includes a video panel, speakers, drive means thereof, and the like, and reproduces and outputs video and audio on the basis of a data signal from the DVD player 9. The computer B12 performs further calculation processing based on the calculation result (data) of the signal transmitted from the computer A10.

The wireless LAN transmission device 1 is configured as described above. Hereinafter, functions of the wireless LAN transmission device 1 will be described.
The user connects the DVD player 9 and the computer A to the data bus 5 on the transmission side, and the video / audio output means 11 and the computer B to the data bus 8 on the reception side as prescribed.
Here, the DVD player 9 and the computer A are connected to the microcomputer 3, and the video / audio output means 11 and the computer B are connected to the microcomputer 7.

The user transmits a data signal from the DVD player 9 via the microcomputer 3 from the communication unit 2 to the communication unit 6 via the channel C1.
Subsequently, the user transmits a data signal from the computer A10 via the microcomputer 3 from the communication unit 2 to the communication unit 6 via the channel C14.
In the initial state of the communication start, the microcomputer 3 uses the channel C14 used for the system for transmitting the data signal from the DVD player 9 and the channel C14 used for the system for transmitting the data signal from the computer A10. Is pre-selected and functions to select a combination of channels that does not cause interference problems in the two systems during communication.

In the case of simultaneously transmitting three or more system signals, the microcomputer 3 functions to assign channels so as to obtain a state in which the frequencies of the respective channels are most separated from each other.
Here, the communication unit 6 receives the data signal from the DVD player 9 sent via the communication unit 2 and using the channel C1, and the communication state at that time is sent to the microcomputer 7.

Here, in the microcomputer 7, the frequency of the channel C1 used for transmission of the data signal from the DVD player 9 is farthest from the channel C14 used for transmission of the data signal from the computer A10. Therefore, it is determined that interference is in the best condition.
Next, the microcomputer 7 determines whether or not the reception state of the data signal of the DVD player 9 transmitted from the communication unit 2 is normally performed. Here, if the reception state of the communication unit 6 is normal and there is no problem, it is not necessary to search for a channel with a better communication state for transmission of the data signal of the DVD player 9 as desired by the user. The LAN transmission device 1 will continue to be used.

On the other hand, the microcomputer 7 determines that the communication state related to the data signal from the DVD player 9 received by the communication unit 6 is not normal, or searches for a channel with a better communication state based on the sequence control of the built-in program. When the function is performed (S1 in FIG. 2), a message to that effect is sent from the communication unit 6 to the microcomputer 3 via the communication unit 2.
Here, the microcomputer 3 controls to temporarily stop the transmission of the data signal from the computer A10, and causes the C2 to C13 to start searching for the channel of the system that transmits the data signal of the DVD player 9. (S2).

For the system for transmitting the data signal of the DVD player 9, the communication unit 6 has a better communication state with respect to the communication unit 2 so as to search for a channel in which the communication state from the communication unit 2 to the communication unit 6 is better. A request signal for searching for a new channel is sent (S3).
When the communication unit 2 receives the request signal from the communication unit 6 and notifies the microcomputer 3 to that effect, the microcomputer 3 should read the data from the memory 4 and assign it to the data signal transmission system from the DVD player 9. In addition to searching for a new channel, a channel that does not cause an interference problem in the communication state with respect to the channel to be newly assigned is selected from the remaining channels and used as a data signal transmission system from the computer A10. The memory 4 is rewritten and stored for allocation.

Here, when the best communication state is obtained by the new channel assigned to the data signal transmission system from the DVD player 9 and the channel is obtained, the microcomputer 3 determines that based on the signal from the microcomputer 7. The search for the channel to be assigned to the data signal transmission system from the DVD player 9 is terminated, and the transmission of the data signal from the DVD player 9 is started via the channel (S4).
Next, the microcomputer 3 calls the channel having the frequency most distant from the channel used in the data signal transmission system from the DVD player 9 from the memory 4, and the communication state from the channel is better. It works to search for new channels.

In this search, the microcomputer 3 starts the channel with the frequency farthest from the channel used for transmission of the data signal from the DVD player 9 (S5), and controls the switching of the channel to the channel with the frequency closer. (S6).
Here, when the best communication state is obtained by the new channel assigned to the transmission system of the data signal from the computer A10 and the channel is obtained (S7), the microcomputer 3 notifies the signal from the microcomputer 7 to that effect. And the search for the channel to be assigned to the transmission system of the data signal from the computer A10 is terminated, and the transmission of the data signal from the computer A10 is started via the channel (S8).

Here, the transmission channel of the data signal from the DVD player 9 and the transmission channel of the data signal from the computer A10 are most separated from each other in the present good communication state obtained by the above-described process. The search for the channel to be assigned by switching to the two systems is completed (S9).
As described above, the wireless LAN transmission apparatus 1 selects and assigns two data signals as different systems from among 14 channels, transmits the data signals, switches to a channel with a better communication state, and performs a search. In this case, after the channel of the other system is switched to the channel that does not cause interference with the channel of the one system, and the search / assignment of the channel of the one system is finished, the channel of the assigned one system Therefore, it is possible to search and assign other channels from among the channels that are less likely to interfere with each other. When searching / switching, there will be interference or a communication error will occur due to searching for channels with better communication conditions. It said problem does not occur.

The wireless LAN transmission device 1 is configured to transmit two data signal systems out of 14 channels, but the number of all channels provided may be other than 14, and the number of data signals to be transmitted The number of systems may be 3 or more.
When the number of data signal systems to be transmitted is three or more, specifically, the channel of one system is obtained with the transmission of all the other systems except the one system stopped. Next, the transmission of all the systems other than the second system is stopped, and the channel of the second system is searched by searching for a channel far away from the channel of the first system that has already been selected. Next, in a state where transmission of all the remaining systems except for the third system is stopped, a search is performed from a channel whose frequency is relatively far from the channel of the first system and the channel of the second system. There is a method in which the system is obtained, and the channels after the fourth system are obtained in the same manner as the channels of the third system. In this case, the search sequence control program can be stored in the memory 4.

In the wireless LAN transmission device 1, the DVD player 5 and the computer A10 are connected to the data bus 5, but other data signal output devices such as a CD player and a receiver may be used. It is preferable to appropriately connect a data signal reproducing device connected to the.
The wireless LAN transmission device 1 is configured to stop transmission of the other data signal system and wait for the channel to be switched when searching for a channel related to one data signal system. The channel related to the data signal system may also be configured to simultaneously switch to a channel in which the frequency at which interference does not occur is most distant.

FIG. 3 is a block diagram showing a configuration in a state in which a DVD player and a computer A are connected to the transmission side, and a video / audio output means and a computer B are connected to the reception side according to the embodiment of the present invention. It is a flowchart explaining the principal part function of the form shown in FIG.

Explanation of symbols

1: Wireless LAN transmission devices 2, 6: Communication units 3, 7: Microcomputer 4: Memory 5, 8: Data bus 9: DVD player (transmission signal generation source)
10: Computer A (source of transmission signal)

Claims (2)

A plurality of channels are provided, two or more signal systems are arbitrarily selected and assigned from among the plurality of channels, and independent signals are transmitted simultaneously, and the channels related to the two or more systems are in communication state. In a wireless LAN transmission device configured to switch to a better channel,
When one of the channels related to the two or more systems used above is switched to a channel having a better communication state, the channel used in the remaining systems with respect to the newly switched channel along with the switching. If there is interference, switch the channels in use of those remaining systems to another channel that can avoid the interference, and in addition, the channels in use of the remaining systems that have been switched to have a better communication status. Wireless LAN transmission device configured to control to switch to a different channel.
  When two or more signal systems are arbitrarily selected and assigned to multiple channels and independent signals are transmitted simultaneously, one of the two or more signal systems is switched to a channel with a better communication state. 2. The wireless LAN transmission device according to claim 1, wherein the remaining system is assigned by switching to a channel having the furthest frequency from the channel used by switching.

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