JPH08331127A - Radio transmission system - Google Patents

Abstract

PURPOSE: To provide a radio transmission system capable of automatically setting the hopping pattern information of an access point in a frequency hopping system. CONSTITUTION: The access point AP receives a beacon signal transmitted from another access point AP by a signal receiving part 5. A signal processing part 6 samples the hopping pattern information included in the beacon signal received by the beacon signal receiving part 5, and selects the hopping pattern information with the lowest probability that coincides with the frequency of sampled hopping pattern information out of the hopping pattern information stored in a storage part 4, and outputs an information signal to inform selected hopping pattern information to a beacon signal generating part 7. The beacon signal generating part 7 generates the beacon signal for a mobile station I located in its own cell based on the content of the information signal inputted from the signal processing part 6, and transmits it from a radio transmission/reception part 1. Therefore, a cell with least interference is constituted in the mobile station I.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless local area network (Local Area Network) using a wired network.
etwork, LAN) wireless transmission system.

[0002]

2. Description of the Related Art FIG. 4 is an overall configuration diagram of a wireless LAN wireless transmission system using a wired network according to a conventional example. Conventionally, an access point AP for converting wired communication and wireless communication is arranged so that cells, which are communication areas thereof, overlap each other, and a spread spectrum communication method is used as a wireless transmission method with a mobile station I. When adopting, the different spreading patterns are selected in order to prevent radio wave interference with the cell which is the communication area of the adjacent access point AP.

As a spread spectrum communication system, a frequency hopping system (SS-FH) and a direct spread system (S
S-DS). The frequency hopping method is a state in which the frequency is spread by sequentially changing the frequency to be used with time, and the access point AP and the mobile station I in the cell configured by the access point AP are It is necessary to change the frequency in synchronization. Therefore, the access point AP is
A beacon signal, which is a signal for synchronization, is transmitted to the mobile station I existing in its own cell. This beacon signal includes hopping pattern information used by itself indicating the pattern of frequency change and hop time indicating the timing of frequency change.
Even by receiving this beacon signal,
Wireless communication can be performed.

The direct spread system spreads the spread data in frequency (spectrum) by superimposing a spread code at a higher speed on the transmission data, and the receiving side removes this in synchronization with the spread code. By doing so, reception is performed. In this method, the same spreading code is generally used in the same cell, and wireless communication is performed in synchronization with the spreading code, so that a beacon signal as in the frequency hopping method is not required. However, it is necessary to inform the new mobile station I of the spreading code used in the cell, and radio waves are emitted at a constant cycle even when there is no communication of information.

FIG. 5 is a schematic diagram showing an example of two pieces of hopping pattern information at the frequency of 8 channels in the frequency hopping method. In FIG. 5, the used frequencies of the two patterns match in the time slot of the seventh slot. When such a state occurs, the two cells use the same frequency for communication, causing interference.

Therefore, it is possible to reduce interference between cells by selecting hopping pattern information that minimizes the hit rate, which is the probability that the frequencies used will be the same frequency.

[0007]

However, in the wireless transmission system as described above, the access point AP
Stores a plurality of pieces of hopping pattern information so that the installer can determine the hopping pattern information used by surrounding access points AP when installing the access point AP, and set the optimum one with a switch or the like. It took a lot of know-how and time to install.

[0008] Further, there is a system in which the access point AP can be managed and set by remote operation from a network management device connected to the wired network CN. The hopping pattern was set sequentially considering the installation location, and it required experience and know-how.

Further, the access points AP operate at independent timings, and even if the time is measured by using a highly accurate signal source, the individual timings are random when operated for a long time. Therefore, when selecting the hopping pattern, it is necessary to consider the entire one cycle of the hopping pattern, and the options are limited.

Further, for the mobile station I, when moving between cells, there is a problem that the synchronization work is required again because the timing of each cell is different.

The present invention has been made in view of the above points, and an object thereof is a wireless transmission system capable of automatically setting hopping pattern information of an access point in a frequency hopping system. To provide.

[0012]

According to the first aspect of the present invention,
A beacon that includes a wired transmission / reception unit that transmits / receives a signal for wired communication, hopping pattern information that indicates a pattern of wireless signal transmission / reception with a mobile station and frequency change, and hop time that indicates the timing of frequency change A wireless transmission / reception unit that transmits a signal, a storage unit that stores the frequency hopping pattern information, a control unit that controls switching between wired communication and wireless communication, and a beacon signal generation unit that generates the beacon signal. A plurality of access points each having a connection to a wired network, and performing wireless communication using a frequency hopping method between the access points and a mobile station existing in a cell which is a communication area of the access point. In the wireless transmission system described above, the storage unit stores a plurality of types of hopping pattern information, and To the point, a beacon signal receiving unit that receives the beacon signal transmitted by another access point, and extract the hopping pattern information included in the beacon signal, hopping pattern information different from the hopping pattern information from the storage unit. A signal processing unit to be selected is added, and the beacon signal generation unit is configured to generate a beacon signal based on the hopping pattern information selected by the signal processing unit.

According to a second aspect of the present invention, in the wireless transmission system according to the first aspect, the signal processing section provides a priority based on the reception intensity of the beacon signal received by the beacon signal receiving section, and at least the priority is set. It is characterized in that hopping pattern information different from the hopping pattern information included in the beacon signal having a high priority is selected.

According to a third aspect of the present invention, in the wireless transmission system according to the first or second aspect, the signal processing section is self-operated when the error of the signal in the wireless communication exceeds a certain value. The feature is that the hopping pattern information is set.

According to a fourth aspect of the present invention, in the wireless transmission system according to the first to third aspects, the signal processing unit is configured to extract the hop time from the beacon signal, and the beacon signal generation unit is The hop time synchronized with the hop time extracted by the signal processing unit is included in its own beacon signal.

According to a fifth aspect of the present invention, in the wireless transmission system according to the fourth aspect, the signal receiving unit receives a beacon signal transmitted by another access point when wireless communication is not performed. It is characterized by having done.

According to a sixth aspect of the present invention, in the wireless transmission system according to the first to fifth aspects, the wire network manages hopping pattern information of a plurality of access points connected to the wire network, and A network management device for changing is added, and the access point transmits its own hopping pattern information to the network management device in the wired transmission / reception unit.

[0018]

According to a first aspect of the present invention, a plurality of types of hopping pattern information indicating a frequency change pattern are stored in a storage unit of an access point which performs conversion between wireless communication and wired communication, and a beacon signal receiving unit Another access point transmits, receives a beacon signal including the hopping pattern information and a hop time indicating the timing of frequency change, and in a signal processing unit, extracts the hopping pattern information included in the received beacon signal. Then, the hopping pattern information different from the extracted hopping pattern information is selected from the storage unit, the beacon signal generation unit generates a beacon signal based on the hopping pattern information selected by the signal processing unit,
In the wireless transmission / reception unit, the beacon signal generated by the beacon signal generation unit is transmitted, and it is possible to configure a cell with the least interference in the cell that is the communication area of the access point.

According to a second aspect of the present invention, in the wireless transmission system according to the first aspect, the signal processing unit sets a priority based on the reception intensity of the beacon signal received by the beacon signal receiving unit, and at least the priority is set. The hopping pattern information different from the hopping pattern information included in the beacon signal having a high priority is selected, and the cell with the least interference can be configured.

According to a third aspect of the present invention, in the wireless transmission system according to the first or second aspect, the signal processing section is self-operated when the signal error in wireless communication exceeds a certain value. Since the hopping pattern information is set, signal errors in wireless communication can be reduced.

According to a fourth aspect of the present invention, in the wireless transmission system according to the first to third aspects, the signal processing unit is configured to extract the hop time from the beacon signal, and the beacon signal generation unit is The hop time synchronized with the hop time extracted by the signal processing unit is included in its own beacon signal, and from the time when the frequency of the hopping pattern information changes until the next change. It is possible to prevent the situation of the used frequency from being changed by another access point changing the frequency, and it is possible to relatively easily select the hopping pattern information.

According to a fifth aspect of the present invention, in the wireless transmission system according to the fourth aspect, the signal receiving section is configured to receive a beacon signal transmitted by another access point when wireless communication is not performed. Therefore, when synchronizing with the hop time of another access point, the influence of the clock frequency used by the access point can be ignored.

According to a sixth aspect of the invention, in the wireless transmission system according to the first to fifth aspects, a hopping of a plurality of access points connected to the wired network to which the access point is connected. A network management device for managing and changing pattern information is added, and the access point transmits its own hopping pattern information to the network management device in a wired transmission / reception unit. Can easily change the hopping pattern information of the access point using the wired network.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of an access point AP when using a frequency hopping method according to an embodiment of the present invention, and FIG. 2 is an overall diagram showing an example of a wireless transmission system according to the present embodiment. It is a block diagram. The access point AP includes a wireless transmission / reception unit 1, a wired transmission / reception unit 2, a control unit 3, a storage unit 4, a beacon signal reception unit 5, a signal processing unit 6, and a beacon signal generation unit 7. Become. The wireless transmission / reception unit 1 transmits / receives a signal for wireless communication with a mobile station I existing in a cell, which is its own communication area, and transmits a beacon signal generated by the beacon signal generation unit 5. It is a thing. The wired transmission / reception unit 2 transmits / receives a signal for wired communication via the wired network CN. The control unit 3 transmits the signal received by the wireless transmission / reception unit 1 from the wired transmission / reception unit 2,
The control is performed so that the signal received by the wired transmitting / receiving unit 2 is transmitted from the wireless transmitting / receiving unit 1. The storage unit 4 stores a plurality of types of hopping pattern information indicating a frequency change pattern. Beacon signal receiver 5
Is to receive a beacon signal transmitted by another access point AP. The signal processing unit 6 extracts the hopping pattern information included in the beacon signal received by the beacon signal receiving unit 5, selects hopping pattern information different from the extracted hopping pattern information from the storage unit 4, and outputs the beacon signal generation unit. The information signal for informing the selected hopping pattern information is output to No. 7.

The operation of this embodiment will be described below.
The access point AP receives the beacon signal transmitted by the other access point AP in the beacon signal receiving unit 5. The signal processing unit 6 extracts the hopping pattern information included in the beacon signal received by the beacon signal receiving unit 5, and selects the frequency of the extracted hopping pattern information from the hopping pattern information stored in the storage unit 4. Select the hopping pattern information that has the lowest matching probability, and
An information signal that informs the selected hopping pattern information is output.

The beacon signal generating section 7 generates a beacon signal for the mobile station I existing in its own cell based on the content of the information signal input from the signal processing section 6, and transmits it from the radio transmitting / receiving section 1. .

Therefore, in the present embodiment, the probability that the frequencies match with each other based on the hopping pattern information contained in the received beacon signal when the beacon signal of the access point AP located nearby is received. Since its own hopping pattern is selected from the storage unit 4 so as to reduce the number of cells, the mobile station I can configure a cell with the least interference.

A network management device for managing and changing the hopping pattern information of the access point AP is connected to the wired network CN, and each access point sends its own hopping pattern information from the wired transmitting / receiving unit 2 through the wired transmitting / receiving unit 2. By transmitting the information to the network management device via the network CN, the network manager can easily know the hopping pattern information of the access point AP in the network by the network management device. The hopping pattern information of the access point AP can be easily changed by using the wired network CN from the management device.

In the actual situation, the number of received beacon signals is rarely one, and beacon signals from a plurality of adjacent access points AP are usually received. FIG. 3 is a flowchart showing a processing flow of hopping pattern information and hop time setting of the access point AP according to another embodiment of the present invention. In the case of the frequency hopping method, all the usable frequencies are regularly repeated at a constant cycle, so the reception state is first set at a specific frequency and the observation time is set. Here, as the observation time, one cycle time of the hopping pattern may be set. Then, the hopping pattern information and the reception intensity included in all the beacon signals received during the observation time are stored.

When a beacon signal is received from a plurality of access points AP, in general, one having a high reception intensity has a large degree of interference, and therefore, in the present embodiment, the reception intensity is weighted. As an example of this weighting,
In the present embodiment, the hit rate of the hopping pattern that is a candidate and the hopping pattern of another access point AP is multiplied by the reception intensity to obtain 1 of the hopping pattern.
The sum of the periods is used as the index. Then, by selecting the hopping pattern information having the smallest index as the best information, the cell with the least interference can be constructed.

In addition, in the above-mentioned two embodiments, when the self hopping pattern is set, if all the access points are synchronized with the hop time included in the beacon signal from another access point AP. A
P will switch the used frequency at the same time, and prevent a change in the status of the used frequency due to another access point AP changing the frequency between the changes of the frequency and the next change. In addition, the selection of hopping pattern information can be made relatively easily.

Further, since the time required to switch the frequency is relatively short (usually 100 μsec or less), it is necessary to maintain the synchronization with high accuracy, and the difference in the clock frequencies used by the individual access points AP. Can not be ignored. At each access point AP, the signal processing unit 6 can determine a time zone during which there is a margin for communication within the cell managed by itself, and a beacon transmitted by another access point AP during this time zone. If the signal is received, the resynchronization can be easily performed, so that the influence of the clock frequency used by each access point can be ignored.

Further, in all the above-mentioned embodiments, each access point AP detects an error in the signal of wireless communication, and when the error exceeds a certain value,
By setting the hopping pattern again, the mobile station I can configure a cell with less interference.

[0034]

According to the first aspect of the present invention, a plurality of types of hopping pattern information indicating a pattern of frequency change are stored in a storage unit of an access point which performs conversion between wireless communication and wire communication, and a beacon signal receiving unit is stored. In, the other access point transmits, the beacon signal including the hopping pattern information and the hop time indicating the timing of the frequency change is received, and the signal processing unit extracts the hopping pattern information included in the received beacon signal. , Hopping pattern information different from the extracted hopping pattern information is selected from the storage unit, the beacon signal generation unit generates a beacon signal based on the hopping pattern information selected by the signal processing unit, the beacon in the wireless transmission and reception unit, Be sure to send the beacon signal generated by the signal generator Runode, the cell is a communication region of the access point, it is possible to constitute the most less interference cell, it is possible to provide a wireless transmission system which can be easily installed the access point.

According to a second aspect of the present invention, in the wireless transmission system according to the first aspect, the signal processing unit sets the priority based on the reception intensity of the beacon signal received by the beacon signal receiving unit, and at least the priority is set. Since the hopping pattern information different from the hopping pattern information included in the high beacon signal is selected, the cell with the least interference can be configured.

According to a third aspect of the present invention, in the wireless transmission system according to the first or the second aspect, the signal processing unit performs its own hopping pattern when the error of the signal in the wireless communication exceeds a certain value. Since information is set, signal errors in wireless communication can be reduced and reliability can be improved.

According to a fourth aspect of the present invention, in the wireless transmission system according to the first to third aspects, the signal processing section comprises:
The hop time is extracted from the beacon signal, and the beacon signal generation unit includes the hop time synchronized with the hop time extracted by the signal processing unit in its own beacon signal. It is possible to prevent the occurrence of a change in the usage frequency situation due to another access point changing the frequency between the changes in the information frequency and the next change, and also in the selection of hopping pattern information. , Can be selected relatively easily.

According to a fifth aspect of the present invention, in the wireless transmission system according to the fourth aspect, the signal receiving section receives a beacon signal transmitted by another access point when wireless communication is not performed. Therefore, when synchronizing with the pop time of another access point, the influence of the clock frequency used by the access point can be ignored.

According to a sixth aspect of the present invention, in the wireless transmission system according to the first to fifth aspects, the hopping pattern information of a plurality of access points connected to the wired network is added to the wired network to which the access points are connected. A network management device for managing and changing the network management device is added, and the access point transmits its own hopping pattern information to the network management device at the wired transmission / reception unit. By using the network, it is possible to easily change the hopping pattern information of the access point.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an access point when a frequency hopping method according to an embodiment of the present invention is used.

FIG. 2 is an overall configuration diagram showing an example of a wireless transmission system according to an embodiment.

FIG. 3 is a flowchart showing a processing flow of hopping pattern and hop time setting of an access point according to another embodiment of the present invention.

FIG. 4 is an overall configuration diagram showing a wireless transmission system of a wireless LAN using a wired network according to a conventional example.

FIG. 5 is a schematic diagram showing an example of two pieces of hopping pattern information at a frequency of 8 channels in the frequency hopping method.

[Explanation of symbols]

 AP access point CN Wired network I Mobile station 1 Wireless transmission / reception unit 2 Wired transmission / reception unit 3 Control unit 4 Storage unit 5 Beacon signal reception unit 6 Signal processing unit 7 Beacon signal generation unit

Claims (6)

[Claims] 1. Hopping pattern information indicating a pattern of frequency change and transmission / reception of a signal of wireless communication between a mobile station and a wire transmitting / receiving unit that transmits / receives a signal of wire communication, and a hop indicating timing of frequency change. A wireless transmission / reception unit that transmits a beacon signal including time, a storage unit that stores the frequency hopping pattern information, a control unit that controls switching between wired communication and wireless communication, and generate the beacon signal. Connecting a plurality of access points having a beacon signal generation unit to a wired network,
In a wireless transmission system configured to perform wireless communication using a frequency hopping method between the access point and a mobile station existing in a cell which is a communication area of the self,
While storing a plurality of types of hopping pattern information in the storage unit, the access point, a beacon signal receiving unit for receiving the beacon signal transmitted by another access point, and the hopping pattern information included in the beacon signal And a signal processing unit that selects hopping pattern information different from the hopping pattern information from the storage unit, and the beacon signal generation unit is a beacon based on the hopping pattern information selected by the signal processing unit. A wireless transmission system characterized by generating a signal. 2. The signal processing unit sets a priority based on the reception intensity of the beacon signal received by the beacon signal receiving unit, and hopping different from hopping pattern information included in the beacon signal having at least a high priority. The wireless transmission system according to claim 1, wherein pattern information is selected. 3. The signal processing unit is configured to set its own hopping pattern information when an error in a signal in wireless communication exceeds a certain value. Item 2. The wireless transmission system according to Item 2. 4. The signal processing unit is configured to extract the hop time from the beacon signal, and the beacon signal generation unit is configured to extract a hop time synchronized with the hop time extracted by the signal processing unit, 4. It is configured to be included in its own beacon signal.
The wireless transmission system described. 5. The wireless transmission system according to claim 4, wherein the signal receiving unit is configured to receive a beacon signal transmitted by another access point when wireless communication is not performed. 6. The network management device for managing and changing the hopping pattern information of a plurality of access points connected to the wired network is added to the wired network, and the access point is configured to perform the wired transmission / reception. 6. The wireless transmission system according to claim 1, wherein the unit transmits its own hopping pattern information to the network management device.