JP2006020056A - Radio transmitter-receiver system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio transmitter-receiver system which can communicate always in the best condition after data frame exchange. <P>SOLUTION: In the radio transmitter-receiver system, the installation type electronic apparatus 100 and the mobile terminal 200 with a noise generation source perform transmitting and receiving of data. When the frame exchange of those other than a series of data frames performed between the installation type electronic apparatus 100 and the mobile terminal 200 is performed until the data frame exchange can be performed, the installation type electronic apparatus 100 is operated in the operation mode in the busy state substantially equal to the real operation state. A radio field strength between the mobile terminals 200 and the congestion condition of the medium are measured. And, various communication parameters are set between the installation type electronic apparatus 100 and the mobile terminal 200. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless transmission / reception system in which a stationary electronic device having a noise generation source and a mobile terminal transmit / receive data.

With the spread of informatization in various fields, there is an increasing demand for speeding up data transmission and convenience for freely carrying terminal devices. A wireless local area network (WLAN) represented by IEEE 802.11 has been put to practical use as a wireless data communication technology indoors, for example, in an office or home. In particular, IEEE802.11 has been rapidly spread along with reductions in the cost of WLAN devices themselves due to improvements in data transfer rates and security.
On the other hand, an image input device such as a scanner, a printing device such as a printer or a FAX, or a composite device having both of them is generally a stationary electronic device. Despite the increased freedom of movement of terminal devices, when using these stationary electronic devices, it was common to connect to a wired LAN. Recently, access points are being developed, but mainly for connection to the Internet, and connection to stationary electronic devices is hardly considered.
In addition, stationary electronic devices having WLAN devices are gradually entering the market. Normally, terminal devices and stationary electronic devices are rarely connected on a one-to-one basis, and are usually connected on a many-to-one basis. The place where the terminal device is placed is not constant.
In FIG. 4, reference numeral 100 denotes a stationary electronic device (printer in this example) having the WLAN device 101, and 200 denotes a terminal device (mobile terminal).
For example, Patent Literature 1 discloses a wireless packet transfer method between a wireless base station (access point) as a stationary electronic device and a terminal device. In this technology, only wireless terminals that are likely to succeed in packet transfer by the direct transfer method are registered in the direct transfer table based on the reception status of the packet transmitted to an arbitrary terminal device in the local station. Only the wireless terminals that are used are subject to the direct transfer method, and the relay transfer method via other wireless base stations is applied to other wireless terminals.
As a conventional technique, a fragment division transmission method for reducing the probability of occurrence of packet errors and an RTS / CTS random access method for avoiding the problem of hidden terminals are described. The radio base station disclosed in the publication is assumed to be installed in a relatively high place with good visibility, for example, the ceiling of the floor. In addition, the communication state between a certain radio base station and a terminal device is described on the assumption that there is no change over time.
Patent No. 30007069

As described above, stationary electronic devices are often placed in the corners of rooms or floors, and there is a problem that they are placed in places with less favorable radio wave conditions. In addition, stationary electronic devices such as printers have many mechanical components such as motors, and the noise level changes greatly between the standby state (idle) and the operating state (busy), so the radio wave state also changes greatly.
In the above prior art, the wireless base station is installed in a place where the radio wave condition is good, and further, the communication state between the wireless base station and the terminal device is assumed not to change over time. It is not a means of avoiding the problems that have occurred.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wireless transmission / reception system capable of always communicating in the best state after data frame exchange.

In order to achieve the above object, the invention described in claim 1 is a wireless transmission / reception system in which a stationary electronic device having a noise generation source and a mobile terminal transmit and receive data until data frames can be exchanged. When exchanging frames other than a series of data frames performed between the stationary electronic device and the mobile terminal, the stationary electronic device is operated in a busy operation mode that is close to an actual operating state, and And measuring various communication parameters between the stationary electronic device and the mobile terminal.
According to the second aspect of the present invention, when exchanging frames before transmission and reception of a series of data frames, the stationary electronic device is busy when it is in a standby state, and the radio field strength between the mobile terminal and the degree of congestion of the medium is measured. When it is determined that the exchange is possible, the communication method between the stationary electronic device and the mobile terminal is changed depending on whether the operation state of the stationary electronic device is idle or busy.
The invention according to claim 3 is characterized in that the radio transmission / reception system according to claim 1 or 2 in which the communication parameter is a fragmentation threshold.
According to a fourth aspect of the present invention, the wireless transmission / reception system according to the first or second aspect is characterized in that the communication parameter is a request-to-send threshold.
The invention according to claim 5 is characterized in that the radio transmission / reception system according to claim 1 or 2 is characterized in that the communication parameters are a fragmentation threshold and a request-to-send threshold.

  In the wireless transmission / reception system of the present invention, when the exchange of frames other than a series of data frames performed between the stationary electronic device and the mobile terminal until the data frame can be exchanged, the stationary electronic device is in a state close to the actual operation state. By operating in the busy operation mode, measuring the radio field strength and medium congestion with the mobile terminal, and setting various communication parameters between the stationary electronic device and the mobile terminal, the intended purpose Can be achieved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram of data exchange in the wireless transmission / reception system according to the first embodiment of the present invention. The operation of the stationary electronic device 100 is shown on the left, and the operation of the terminal device 200 is shown on the right. A frame exchange is shown by an arrow between the two. Frames are transmitted and received in numerical order (from top to bottom in the figure). This figure shows a case where the stationary electronic device 100 operates as an access point (infrastructure mode).
Hereinafter, it demonstrates in order. When the stationary electronic device 100 is activated (powered on), beacon frames are transmitted at certain intervals. When the terminal device 200 is ready and communication is started, scanning (SCAN) is first started. FIG. 1 shows a case where a so-called passive scan is executed. In the case of an active scan, a probe request and a probe response frame are transmitted and received. First, the terminal device 200 collects information about what wireless system is currently available by scanning. In this embodiment, the case where beacon frames 1 to 3 are received is shown.
Next, a join (JOIN) is performed from 4 to 6, and a BSS managed by the stationary electronic device 100 is joined. Next, the terminal device 200 transmits an authentication request for authentication (AUTH) to the stationary electronic device 100 at 7. By this request, the stationary electronic device 100 knows the existence of the terminal device 200 and at the same time obtains information such as the function of the terminal device 200.
Thereafter, the stationary electronic device 100 is in a state close to the actual operation (busy state, for example, a printer or the like does not actually print, the mechanism part is operated by a warm-up operation or the like, and the noise level is brought to a state close to the actual operation state. The authentication response is terminated by transmitting an Authentication response to the terminal device 200 in 8.
In this state, the terminal device 200 transmits an association request for association (ASSOC) at 9 to the stationary electronic device 100, and transmits an association response to the terminal device 200 at 10 to end the association. Thereafter, stationary electronic device 100 returns to the idle state. The stationary electronic device 100 and the terminal device 200 can set various communication parameters by measuring the radio field intensity and the degree of congestion in a busy state by exchanging frames of 8, 9 and 10.

FIG. 2 is an explanatory diagram of data exchange in the wireless transmission / reception system according to the second embodiment of the present invention. The case of the ad hoc mode, which is another WLAN operation mode, is described.
In this case, when the stationary electronic device 100 is activated (powered on), beacon frames are transmitted at certain intervals as in the infrastructure mode. The terminal device 200 collects information on what radio system is currently available by scanning (SCAN). In this embodiment, the case where beacon frames 1 to 3 are received is shown.
Next, a join (JOIN) is performed from 4 to 6. The ad hoc mode starts up. Thereafter, the terminal device 200 transmits the beacon frames from both the stationary electronic device 100 and the terminal device 100 at certain intervals after 7. Thereby, the stationary electronic device 100 knows the existence of the terminal device 200 and simultaneously obtains information such as the function of the terminal device 200.
Thereafter, the stationary electronic device 100 is in a state close to the actual operation (busy state, for example, a printer or the like does not actually print, but operates the mechanism part by a warm-up operation or the like, and the noise level is close to the actual operation state. The beacon frame is exchanged from 8 to 10. Thereafter, stationary electronic device 100 returns to the idle state. The stationary electronic device 100 and the terminal device 200 can set various communication parameters by measuring the radio field intensity and the degree of congestion in a busy state by exchanging frames of 8, 9 and 10.

FIG. 3 is an explanatory diagram of data exchange in the wireless transmission / reception system according to the third embodiment of the present invention. It shows a case of operating in ad hoc mode. The exchange of up to 10 frames measures the radio field intensity and congestion in both the idle state and the busy state, and the setting of various communication parameters is completed. 11, the data frame is transmitted from the terminal device 200 to the stationary electronic device 100.
At this time, since the stationary electronic device 100 is still in the idle state, the data frame is transmitted using the parameters in the idle state. Thereafter, when the stationary electronic device 100 changes to a busy state, the terminal device 200 is notified of this at 12. The terminal device 200 recognizes that the stationary electronic device 100 has changed to the busy state, switches to the parameter in the busy state, and transmits 13 data frames.
Next, when the stationary electronic device 100 changes to the idle state again, the terminal device 200 is notified of that at 14. The terminal device 200 recognizes that the stationary electronic device 100 has changed to the idle state, switches to the parameter in the idle state, and transmits 15 data frames.
As described above, according to the present invention, it is possible to appropriately switch to the two parameters of the idle state and the busy state set before transmitting the data frame, and data transmission / reception can always be performed in a good radio wave state.

Example 1
In the first embodiment, a fragment division transmission method in which the fragmentation threshold is changed is adopted as the above parameter. As a result, the probability of occurrence of packet errors can be reduced.
(Example 2)
In Example 2, the RTS / CTS random access method is used in which the request to send threshold is changed as the above parameter. Thereby, the problem of a hidden terminal can be solved.
Example 3
In Example 3, both the fragment division transmission method and the RTS / CTS random access method that change the fragmentation threshold and the request-to-send threshold are employed as the above parameters. Thereby, both the probability of occurrence of packet errors and the problem of hidden terminals can be reduced.

Explanatory drawing of the data transfer in the radio | wireless transmission / reception system which concerns on the 1st Embodiment of this invention. Explanatory drawing of the data transfer in the radio | wireless transmission / reception system which concerns on the 2nd Embodiment of this invention. Explanatory drawing of the data transfer in the radio | wireless transmission / reception system which concerns on the 3rd Embodiment of this invention. The figure which shows the installation aspect of a stationary electronic device.

Explanation of symbols

100 Stationary Electronic Device 200 Terminal Device (Mobile Terminal)

Claims (5)

  In a wireless transmission / reception system in which data is transmitted and received between a stationary electronic device having a noise source and a mobile terminal, a series of data frames performed between the stationary electronic device and the mobile terminal until the data frame can be exchanged When exchanging frames other than the above, the stationary electronic device is operated in an operating mode in a busy state that is close to the actual operating state, and the radio field strength and medium congestion with the mobile terminal are measured. A wireless transmission / reception system characterized by setting various communication parameters between an electronic device and a mobile terminal.   At the time of frame exchange before a series of data frame transmission / reception, it was determined that the frame could be exchanged by measuring the radio wave intensity and medium congestion with the mobile terminal even when the stationary electronic device was busy. 2. The wireless transmission / reception system according to claim 1, wherein a communication method between the stationary electronic device and the mobile terminal is changed depending on whether an operation state of the stationary electronic device is idle or busy.   The wireless transmission / reception system according to claim 1 or 2, wherein the communication parameter is a fragmentation threshold.   The wireless transmission / reception system according to claim 1 or 2, wherein the communication parameter is a request to send threshold. The wireless transmission / reception system according to claim 1 or 2, wherein the communication parameters are a fragmentation threshold and a request to send threshold.

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