JPH05102969A - Radio local area network - Google Patents

Abstract

PURPOSE:To prevent the throughput of data transmission in a LAN from being lowered by directly transmitting a signal by radio between terminal side transmission equipment at a transmission side and that at a reception side when their positions are within a radio transmission feasible area. CONSTITUTION:Radio transmission/reception means are provided at network side transmission equipment 1 that is a station of a radio LAN and a terminal side transmission equipment 2 connected to a terminal 5. The signal can be transmitted on a radio transmission line between them when the positions of the equipment 2 connected to the terminal 5 from which the signal is delivered and the equipment 2 connected to the terminal 5 that is the delivery destination of the signal are within the radio transmission feasible area. Therefore, the signal is not passed on a transmission line consisting of the equipment 1 and a LAN medium 3. Thereby, it is possible to prevent the throughput of the data transmission in the LAN from being lowered without increasing latency time in signal transmission even when the number of terminals connected to the LAN is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless LAN using the CSMA / CD system.

[0002]

2. Description of the Related Art In recent years, with the widespread use of portable and portable computers, portable wireless terminals, etc., the mobility of terminals connected to a LAN has become a problem, and realization of a wireless LAN is required. Conventionally, as a device of this type, Japanese Patent Laid-Open No. 62-2
There is one disclosed in Japanese Patent No. 33941. FIG. 4 is a block diagram of a conventional CSMA / CD bus system LAN shown in the above document. In the figure, 3 is a LAN medium such as a coaxial cable, 4 is a terminator, 5 is a terminal, 24 is a satellite, and 25 is a terminal.

Next, the operation will be described. The signal from the terminal 5 is converted into light or radio waves by the photoelectric conversion element via the terminal 25 and transmitted to the space. Satellite 24
Then, the light or the radio wave transmitted through the terminal 25 is received, converted into a signal by the photoelectric conversion element, and transmitted to the LAN medium 3. Also, the signal from the LAN medium 3 is converted into light or radio waves by a photoelectric conversion element and transmitted to the space. On the other hand, the terminal 25 receives a signal from the satellite 24, converts it into a signal by a photoelectric conversion element, and sends it to the terminal 5. In the satellite 24, when the signal from the terminal 25 is sent to the LAN medium 3,
By comparing the signal sent to the LAN medium 3 and the signal returned from the LAN medium 3, the collision of signals that occurs when a plurality of satellites 24 simultaneously send signals to the LAN medium 3 is detected. When the signal collision is detected, the collision signal is transmitted to the terminal 25. The terminal 25 receives the collision signal and notifies the terminal 5 of the occurrence of the signal collision.
Let me know. When no signal collision is detected, the above-mentioned folded signal is transmitted to the terminal 25. Further, at the terminal 25, the source transmission signal from the terminal 5
The signal collision is detected by comparing the signal returned by the LAN medium 3.

[0004]

In the conventional example, since the configuration is as described above, all signals from the terminal are LAN.
It is transmitted to the destination terminal via the medium. for that reason,
While a signal is being transmitted between a certain terminal via the LAN, the LAN medium is occupied by that terminal, and until another terminal using the LAN ends communication and the LAN is released, another terminal Is put in a waiting state. Therefore, LAN
When the number of terminals connected to the PC increases, the use of the LAN medium increases, the waiting time for signal transmission increases, and the throughput of LAN data transmission decreases. Also,
In the conventional example, the signal collision detection means is a satellite 24,
In addition to the provision of the terminal 25, it is also necessary to detect the collision signal transmitted from the satellite 24 to the terminal 25 to inform the terminal 25, which causes a problem that the circuit configuration becomes complicated.

The present invention has been made to solve the above problems, and does not increase the waiting time for signal transmission even if the number of terminals connected to the LAN increases, thereby reducing the throughput of LAN data transmission. It is an object of the present invention to obtain a wireless LAN to be prevented, and to obtain a wireless LAN having a simplified device scale by integrating signal collision detection means.

[0006]

In order to achieve the above object, in the wireless LAN according to claim 1 of the present invention, L
A network side transmission device which is a station of AN;
Both the terminal side transmission device connected to the terminal is provided with a wireless transmission / reception means, and the terminal side transmission device connected to the signal sending terminal and the terminal side transmission device connected to the signal destination terminal etc. If the positions are within the area where stable wireless transmission is possible, from the terminal side transmission device connected to the terminal transmitting the above signal to the network side transmission device, LAN
The medium, other network side transmission device, regardless of the transmission line consisting of the terminal side transmission device connected to the terminal of the signal destination, so that the signal transmission by the wireless transmission line between the above both terminal side transmission devices, It is composed. A wireless LAN according to a second aspect of the present invention is the wireless LAN according to the first aspect, including a network-side transmission device having the following elements and a terminal-side transmission device. (A) A terminal-side transmission device having the following elements, (a
1) A signal from a terminal is converted into a CSMA / CD system LAN signal and transmitted to a spread spectrum modulation unit, or a CSMA / CD system LAN output from a spread spectrum demodulation unit.
A transceiver unit for converting a signal into a signal that can be transmitted to a terminal and sending the signal to the terminal; (a2) a spread spectrum modulation unit for performing spread spectrum modulation on the output of the transceiver unit using an address of a signal destination; (a3) a received signal; A spread spectrum demodulation unit that performs spread spectrum demodulation using a despreading code determined in advance for this terminal side transmission device and sends the output to the transceiver unit, (a4) collision of signals on LAN medium, and wireless transmission Signal collision detection means for monitoring the signal collision at the time, (b) a network side transmission device having the following elements, (b1) a signal wirelessly transmitted from the terminal side transmission device to this network side transmission device in advance. A spread spectrum demodulation unit that performs spread spectrum demodulation using a specified despreading code, and a spectrum output unit that outputs the output to a LAN medium. Le spread transmission unit, (b2) receiving the signal on the LAN medium, using the address of the destination of the signal, the spread spectrum modulator for spread spectrum modulation.

[0007]

The wireless LAN of the present invention configured as described above
Then, with the terminal side transmission device connected to the terminal sending the signal,
If the positions of the terminal-side transmission devices connected to the signal destination terminal are mutually within an area where stable wireless transmission is possible, the signal transmission directly from the terminal-side transmission device connected to the signal transmission terminal By transmitting the signal through the wireless transmission path to the terminal side transmission device connected to the destination terminal etc.,
Even if the number of terminals connected to the LAN increases, the waiting time for signal transmission does not increase and it is possible to prevent the throughput of data transmission on the LAN from decreasing. In addition, the LAN medium and the wireless transmission line
The LA medium is regarded as equivalent to the LAN medium in the wired LAN.
The device scale can be simplified by providing the collision detection means for the signal on the N medium and the signal at the time of wireless transmission only on the terminal side transmission device.

[0008]

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 shows a CSMA / C showing a first embodiment of the present invention.
It is a block configuration diagram of a wireless LAN using the D method. In the figure, 1 is a network-side transmission device, 2 is a terminal-side transmission device, and 3 to 5 are the same as those in the conventional example, and a description thereof will be omitted.

FIG. 2 is an internal block diagram of the terminal side transmission device 2 of FIG. Reference numeral 6 is a CSMA / CD type transceiver unit. This transceiver unit 6 sends a signal from the terminal to the CS
Means for converting to a MA / CD type LAN signal and transmitting it to the spread spectrum modulation section 9, and the spread spectrum demodulation section 13
It has means for converting the CSMA / CD system LAN signal from the above into a signal which can be transmitted to the terminal 5. Further, the transceiver unit 6 has means for comparing the signal from the terminal with the signal returned by the medium 3 and the other terminal-side transmission device 2 or the network-side transmission device 1 to detect a signal collision. ..

Numeral 7 indicates CSMA / in the transceiver unit 6.
An address detecting unit for detecting an address of a destination of a signal from a terminal converted into a CD system signal, and 8 a spread spectrum code generating unit for generating a predetermined spread spectrum code based on the address detected by the address detecting unit 7. , 9 is a spread spectrum modulator for spreading and modulating the signal from the terminal using the above spread spectrum code, 10 is an amplifier for amplifying the signal spread and modulated by the spread spectrum modulator 9, and 11 is an antenna for transmission and reception. It is an antenna duplexer for. 12 is an amplification unit for amplifying the received signal,
Reference numeral 13 denotes a spread spectrum demodulation unit that performs spread spectrum demodulation of the received signal using a despreading code determined in advance for the terminal side transmission device and sends the demodulated signal to the transceiver unit 6. Reference numeral 14 denotes a transmission / reception antenna, which is located within the wireless service area of the network-side transmission device for transmission / reception with the network-side transmission device, or is located in an area where mutual position stable radio transmission is possible. It is for transmitting and receiving with the terminal side transmission device.

Next, FIG. 3 is an internal block diagram of the network side transmission device 1 of FIG. In the figure, 15 is a network receiving unit for receiving a signal on the LAN medium 3, 16 is an address detecting unit for detecting a destination address of the signal on the LAN medium 3 received by the network receiving unit 15, and 17 is an address detecting unit 16. A spread code generator for generating a predetermined spread code for the detected address, a spread spectrum modulator 18 for spread spectrum modulating a signal received from the LAN medium by the network receiver 15 using the spread code, 19 Is an amplification unit that amplifies the signal spread spectrum modulated by the spread spectrum modulation unit 18, and 20 is an antenna duplexer that shares an antenna for transmission and reception. Reference numeral 21 is an amplification unit for amplifying a signal wirelessly transmitted from the terminal side transmission apparatus, and 22 is a spectrum for performing spread spectrum demodulation of the signal from the terminal side transmission apparatus using a despreading code determined in advance for the network side transmission apparatus. Spread demodulator, 23
Is a network transmission unit for transmitting the above-described spread spectrum demodulated signal onto the LAN medium 3.

The operation of the wireless LAN having the above configuration will be described. First, an operation of wirelessly transmitting a signal from the terminal 5 to the terminal-side transmission device 2 connected to the destination terminal via the transmission-side terminal-side transmission device 2 or to the network-side transmission device 1. Will be described. The signal from the terminal 5 is input to the terminal side transmission device 2 on the transmission side. A signal from the terminal 5 input to the terminal-side transmission device 2 is converted into a CSMA / CD system signal by the transceiver unit 6. From this signal, the address detection unit 7 detects the address of the destination of the signal. If the positions of the terminal-side transmission device 2 connected to the signal-destination terminal 5 and the position of the transmission-side terminal-side transmission device 2 are within the area where stable wireless transmission is possible, the spreading code generation unit 8 Destination terminal 5
A predetermined spreading code is generated in the terminal side transmission device 2 connected to. On the other hand, if the positions of the terminal-side transmission device 2 connected to the signal-destination terminal and the transmission-side terminal-side transmission device 2 are not within the area described above, the transmission-side terminal-side transmission device 2 A predetermined spreading code is generated in the network side transmission device 1 whose position is within the wireless service area. Using the spreading code generated by the spreading code generation unit 8 described above, the signal input from the terminal 5 and converted by the transceiver unit 6 into the LAN signal of the CSMA / CD system is spread spectrum modulated and amplified by the amplification unit 10. ,
The signal is transmitted from the antenna 14 via the antenna duplexer 11.

Next, the transmission device 1 on the network side transmits the signal transmitted wirelessly from the transmission device 2 on the terminal side on the transmission side to the LAN.
The operation of transmitting on the medium 3 and receiving the signal on the LAN medium 3 and wirelessly transmitting the signal to the terminal side transmission device 2 connected to the terminal of the destination of the signal will be described. In the network-side transmission device 1, after receiving the signal from the transmission-side terminal-side transmission device 2 and amplifying it with the amplifier 21, the spread spectrum demodulation unit 22 causes the network-side transmission device 1 to de-spread the predetermined despreading code. By performing spread spectrum demodulation using, the multiple access of spread spectrum communication is utilized and only the signal transmitted to the network side transmission device 1 is received. Then, the received signal is transmitted from the network transmission unit 23 onto the LAN medium 3. When the signal is being sent to the LAN medium 3,
The network receiving unit 15 receives the signal sent out on the LAN medium 3 and the spread signal (the signal returned on the LAN medium 3) is transmitted to the terminal side transmission device 2 on the transmitting side by the spread spectrum modulation unit 18. Spread spectrum modulation is performed using a predetermined spreading code, amplified by an amplifier 19, wirelessly transmitted from an antenna 14 via an antenna duplexer 20,
It is used for signal collision detection on the LAN medium 3 in the terminal side transmission device 2 on the transmission side.

When the network-side transmission device 1 does not receive the signal from the transmission-side terminal-side transmission device 2, the network reception unit 15 receives the signal on the LAN medium 3 and the address detection unit 16 receives the signal. Detects the address of the terminal to which the signal is transmitted, and when the terminal-side transmission device 2 connected to the signal-destination terminal is within the wireless service area of the network-side transmission device 1, the spreading code generation unit At 17, using a predetermined spreading code for the terminal side transmission device 2 connected to the terminal of the signal destination,
The spread spectrum modulator 18 spread-spectrum modulates the received signal on the LAN medium 3, amplifies it with an amplifier 19, and then transmits it from the antenna 14 via the antenna duplexer 20. If the terminal-side transmission device 2 connected to the signal-destination terminal is not within the wireless service area of the network-side transmission device 1, the network-side transmission device 1 generates a spreading code or spreads the spectrum. No modulation and no transmission.

Next, the operation of the terminal-side transmission device 2 for receiving signals from the network-side transmission device 1 and other terminal-side transmission devices 2 and sending them to the destination terminal 5, and the operation for detecting signal collisions. Will be described. If the terminal-side transmission device 2 is within the wireless service area of the network-side transmission device 1, or if the positions of other terminal-side transmission devices 2 are within the area where mutual stable wireless transmission is possible, Of the signal of the amplifier 12 and receives the signal of the amplifier 12
And then spread spectrum demodulating section 13 performs spread spectrum demodulation on the terminal side transmission apparatus 2 by using a predetermined despreading code, so that the terminal transmission apparatus 2
Identify and demodulate the signal transmitted to. Then, the received signal is transmitted to the transceiver unit 6. The signal sent to the transceiver unit 6 is converted into a signal that can be transmitted to the terminal 5 from the CSMA / CD system and sent to the terminal 5.

When the input signal of the transceiver unit 6 is a signal transmitted from another transmission device 2 on the terminal side in particular, a spreading code predetermined for the transmission device 2 on the terminal side is used to spread-modulate the signal again. Then, the data is transmitted back to the terminal side transmission device 2 on the transmission side for collision detection during wireless transmission.

Further, in the transceiver unit 6, when the signal from the terminal 5 is wirelessly transmitted to the other terminal side transmission device 2 or the network side transmission device 1, the source signal from the terminal 5 and the other terminal are transmitted. The signal collision is monitored by comparing the signals returned by the side transmission device 2 and the network side transmission device 1. When a signal collision occurs, the returned signal and the source signal are different regardless of the location of the collision on the LAN medium or on the network side transmission device during wireless transmission. Can be detected. In the present invention, since the signal collision detection means is provided only in the transceiver unit 6 of the terminal-side transmission device 2, wireless transmission of the collision signal is eliminated as in the case of the conventional example, and the collision signal transmission is not performed. There is an advantage that collision detection error due to transmission error can be prevented.

In the above embodiment, the terminal side transmission device 2 having the wireless transmission / reception means connected to the terminal 5 having no wireless transmission / reception means has been described as an example, but the present invention is not limited to this, and the wireless terminal is not limited thereto. The same applies to an integrated structure having the function of the terminal-side transmission device described above.

In the above embodiments, the LAN medium 3 has been described by taking a coaxial cable or a twisted pair as an example, but it goes without saying that the present invention can be realized by an optical cable.
In the above-described embodiment, the address detection unit 7 detects the address of the signal destination from the signal obtained by converting the signal from the terminal into the CSMA / CD signal by the transceiver unit 6, but the signal from the terminal is used to detect the signal. It is needless to say that the present invention can be realized even if the destination address is detected. Further, in the above embodiment, the antenna duplexers 11, 20
Although the example in which the transmission / reception antenna 14 is shared is described above, it goes without saying that the present invention can be realized even when separate antennas are used for transmission / reception without using an antenna duplexer. In the above embodiment, the spread spectrum communication method is used for wireless transmission, and the spread code generators 8 and 17 of each device generate a spread code unique to the destination of the signal to realize the multiple access function. However, the spread code generators 8 and 17 are frequency synthesizers, and the spread spectrum modulators 9 and 18 are used as modulators of other modulation schemes.
Realization of multiple access function by replacing the spread spectrum demodulators of Nos. 3 and 22 with demodulators of other modulation schemes, using modulation schemes other than spread spectrum communication schemes for wireless transmission, and assigning different frequencies to each device It goes without saying that the present invention can be realized even in such a case.

[0020]

Since the present invention is constructed as described above, it has the following effects.

If the positions of the terminal-side transmission device for wirelessly transmitting the signal from the terminal and the terminal-side transmission device connected to the destination of the signal are within an area where mutual stable wireless transmission is possible, Wireless transmission from a terminal-side transmission device connected to a signal-sending terminal directly to a terminal-side transmission device connected to a signal-destination terminal without passing through a network-side transmission device of a LAN station or a LAN medium With this configuration, it is possible to obtain a wireless LAN that prevents a decrease in the throughput of data transmission of the LAN even if the number of terminals connected to the LAN increases.

In addition, the LAN medium and the wireless transmission line are connected to each other via a wired L
Assuming that it is equivalent to the LAN medium in AN, the collision detection means for signals on the LAN medium during wireless transmission is provided only on the terminal side transmission device, whereby a wireless LAN with a simplified device scale can be obtained.

Within the wireless service area of each network-side transmission device, it is possible to obtain a wireless LAN in which terminals can easily move.

[Brief description of drawings]

FIG. 1 is a block diagram of a wireless LAN showing a first embodiment of the present invention.

FIG. 2 is an internal configuration diagram of the terminal-side transmission device of FIG.

FIG. 3 is an internal configuration diagram of the network-side transmission device of FIG.

FIG. 4 is a block diagram of a wireless LAN showing a conventional example.

[Explanation of symbols]

 1 Network side transmission apparatus 2 Terminal side transmission apparatus 3 LAN medium 4 Terminator 5 Terminal 6 Transceiver section 7 Address detection section 8 Spreading code generation section 9 Spread spectrum modulation section 10 Amplification section 11 Antenna duplexer 12 Amplification section 13 Spread spectrum demodulation section 14 antenna 15 network receiving unit 16 address detecting unit 17 spreading code generating unit 18 spread spectrum modulating unit 19 amplifying unit 20 antenna duplexer 21 amplifying unit 22 spread spectrum demodulating unit 23 network transmitting unit

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[Procedure amendment]

[Submission date] March 23, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

In order to achieve the above object, in the wireless LAN according to claim 1 of the present invention, L
A network side transmission device which is a station of AN;
Both the terminal side transmission device connected to the terminal is provided with a wireless transmission / reception means, and the terminal side transmission device connected to the signal sending terminal and the terminal side transmission device connected to the signal destination terminal etc. If the positions are within the area where stable wireless transmission is possible, from the terminal side transmission device connected to the terminal transmitting the above signal to the network side transmission device, LAN
The medium, other network side transmission device, regardless of the transmission line consisting of the terminal side transmission device connected to the terminal of the signal destination, so that the signal transmission by the wireless transmission line between the above both terminal side transmission devices, It is composed. A wireless LAN according to a second aspect of the present invention is the wireless LAN according to the first aspect, including a network-side transmission device having the following elements and a terminal-side transmission device. (A) A terminal-side transmission device having the following elements, (a
1) A signal from a terminal is converted into a CSMA / CD system LAN signal and transmitted to a spread spectrum modulation unit, or a CSMA / CD system LAN output from a spread spectrum demodulation unit.
A transceiver unit for converting a signal into a signal that can be transmitted to a terminal and sending the signal to the terminal; (a2) a spread spectrum modulation unit for performing spread spectrum modulation on the output of the transceiver unit using an address of a signal destination; (a3) a received signal; A spread spectrum demodulation unit that performs spread spectrum demodulation using a despreading code determined in advance for this terminal side transmission device and sends the output to the transceiver unit, (a4) collision of signals on LAN medium, and wireless transmission Signal collision detection means for monitoring the signal collision at the time, (b) a network side transmission device having the following elements, (b1) a signal wirelessly transmitted from the terminal side transmission device to this network side transmission device in advance. a spread spectrum demodulator for spread spectrum demodulation using the inverse spreading code which is defined, net sends the output to the LAN medium Over click transmission unit, (b2) receiving the signal on the LAN medium, using the address of the destination of the signal, the spread spectrum modulator for spread spectrum modulation.

Claims (2)

[Claims] 1. A wireless local area network using the CSMA / CD system (hereinafter referred to as local area network).
In a network abbreviated as LAN), both the network-side transmission device that is a station of the LAN and the terminal-side transmission device that is connected to the terminal are provided with wireless transmission means, and the terminal side that is connected to the terminal that sends the signal If the positions of the transmission device and the transmission device on the terminal side connected to the terminal to which the signal is sent are within the area where stable wireless transmission is possible, the transmission on the terminal side connected to the terminal sending the above signal From the device to the network side transmission device which is a station of the LAN, the LAN medium, another network side transmission device, and the transmission line consisting of the terminal side transmission device connected to the terminal of the signal destination A wireless LAN configured to perform signal transmission via a wireless transmission path between devices. 2. The wireless LAN according to claim 1, further comprising a network-side transmission device having the following elements and a terminal-side transmission device: (a) a terminal-side transmission device having the following elements: (A1) The signal from the terminal is a CSMA / CD system LAN
A transceiver unit for converting the signal into a signal and transmitting it to the spread spectrum modulating unit, or converting a CSMA / CD system LAN signal output from the spread spectrum demodulating unit into a signal that can be transmitted to the terminal and transmitting it to the terminal, (a2) the transceiver A spread spectrum modulator that spread-spectrum modulates the partial output using the address of the signal destination, (a3) spread spectrum demodulates the received signal using a despreading code previously determined for this terminal side transmission device,
A spread spectrum demodulation section for sending its output to the transceiver section; (a4) signal collision detection means for monitoring signal collisions on a LAN medium and signal collisions during wireless transmission; (b) having the following elements A transmission device on the network side, (b1) a spread spectrum demodulation unit for performing spread spectrum demodulation on a signal wirelessly transmitted from the transmission device on the terminal side by using a despreading code predetermined for this transmission device on the network side, and an output thereof. A spread spectrum transmitter for transmitting on a LAN medium, (b2) A spread spectrum modulator for receiving a signal on a LAN medium and performing spread spectrum modulation using the address of the destination of the signal.