JPH1032574A - Mobile network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption by reducing power consumption for a network system of equivalent distribution type as small as possible thereby prolonging the service life of a battery and decreasing the operating time of a circuit part handling a radio frequency especially because the circuit part requires much power. SOLUTION: Radio terminal equipments belonging to a group optionally consisting of a plurality of radio terminal equipments 1-4 make equally distributed network communication. When a group is going to start communication, a host terminal equipment of the group at first selects a channel used in the group and the host terminal equipment and the terminal equipments belonging to the group sense the channel for each prescribed time and reach the reception state only when a signal is sensed. Thus, the power consumption of the transceiver is remarkably reduced through the intermittent reception at a prescribed time interval and the operating time of the radio terminal equipments driven by a battery is considerably prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile network system in wireless communication, a network, an access system, and the like.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 6-29981 (transmission control method and apparatus for a wireless local area network station) discloses a receiving apparatus for receiving a signal in a local area network for receiving a signal on a wireless transmission channel. A receiving device for transmitting a signal, a receiving level determining device indicating a signal level received by the receiving device via a transmission channel, a threshold level circuit device for providing a level indicating signal, and a transmitting device based on the level indicating signal By having a transmission control device that controls the operation of
It is described that high LAN performance is realized.

Japanese Patent Application Laid-Open No. 5-260051 (wireless local area network) discloses that a network composed of a plurality of wireless terminals and a central station capable of transmitting and receiving all of the wireless terminals indicates the entire frequency band available. A radio system is described in which a central station has a role of a repeater by dividing into three, a channel, a channel tone up, and a channel tone down, and facilitates transmission and reception between terminals.

[0004]

In the above-mentioned system, the channel of each group is selected, and after the channel is selected, the CSMA / CA (C) is set within the group.
arrier Sense MultipleAccess / Collision Avoidance)
Communication is performed in such a manner. At this time, since the wireless terminal does not know when there is a transmission packet, it must always be in a receiving state. Therefore, there is a disadvantage that the battery driving time of the wireless terminal is shortened due to the large power consumption of the receiving circuit. Also, in a system capable of centralized control such as a cellular phone having a base station, intermittent reception is possible, but it is difficult in a peer-to-peer network system.

An object of the present invention is to extend battery life by reducing power consumption as much as possible in a peer-to-peer network system. In particular, a circuit portion that handles radio frequency requires power. , By minimizing the time to operate this part,
The power consumption is reduced.

Therefore, according to the present invention, when configuring a peer-to-peer network in which communication is performed within a group consisting of arbitrary wireless terminals, power consumption is reduced and battery operating time of the wireless terminals is extended. Can be.

[0007]

According to a first aspect of the present invention, in a wireless network in which wireless terminals belonging to a group arbitrarily constituted by a plurality of wireless terminals perform peer-to-peer distributed network communication, a certain group performs communication. When trying to start, the terminal hosting the group first selects the channel to be used in the group, and the host terminal and the terminals belonging to the group sense the channel at regular intervals, and the signal is detected. It is characterized by being in the receiving state only when the wireless terminal is in use, so that intermittent reception is performed at regular time intervals, the power consumption of the transceiver can be greatly reduced, and the operating time of the battery-powered wireless terminal is greatly reduced It is longer.

According to a second aspect of the present invention, in the mobile network system according to the first aspect, packet transmission is performed by randomly shifting a transmission start time within a certain fixed time, thereby shifting a transmission start time. Thus, collision of transmission packets is eliminated.

A third aspect of the present invention is the mobile network system according to the first aspect, wherein a time slot is allocated to each terminal in the group, and each terminal performs transmission in the time slot allocated to its own station. Thus, by allocating a time slot to each terminal, it is possible to eliminate collision of transmission packets and perform reliable transmission.

According to a fourth aspect of the present invention, in the mobile network system of the first aspect, there is provided a mode in which a certain terminal can transmit in a continuous time slot. Is used to enable efficient packet transmission.

[0011]

FIG. 1 is a diagram showing an example of the configuration of a wireless local area network for a mobile network to which the present invention is applied. The wireless terminals forming each group include a server and a client, respectively. It does not matter, and it forms a peer-to-peer network when communicating. The radio channel for each group is based on FDMA (Frequency Division Multiple Accesses).
s), the frequencies are different from each other, and CDMA
In the case of (Code Division Multiple Access), it may be performed by code division using a spreading code. The following embodiment shows an example of CDMA.

[0012]

Embodiment 1 FIG. 2 is a diagram showing a configuration example of a wireless terminal for a wireless network according to the present invention. In the figure, 11 is a spreading code generator, 12 is a correlation detector, 13 is a channel controller, and 14 is The computer itself, 15 is a network controller, 16 is a transceiver, 17 is an antenna,
The wireless terminal includes a transceiver 16 for performing spreading by a spreading code, modulating / demodulating a data packet, and transmitting / receiving a carrier, a spreading code generator 11 for supplying a selected spreading code to the transceiver 16, a transceiver 16 and a computer main unit 14. Network controller 15 which mediates data transmitted to and received from, and controls peer-to-peer distributed network communication, and outputs the selected spreading code and transceiver 1
6 and a channel controller 13 for controlling their transmission and reception.
Since this is an example of a terminal that performs DMA, a spreading code can be selected.

When the host terminal attempts to start communication, it senses each code and sets an empty channel as a wireless channel used in a group. Thereafter, the host terminal or the group member terminal performs packet transmission at a predetermined time interval. The time during which packet transmission is performed is called a time slot.

FIG. 3 is a diagram showing an example in which a packet is transmitted in a time slot. FIG. 3 (a) shows a radio channel, and transmission is performed from a terminal which is a time slot 3. FIG. 3B shows the O of the transceiver receiving unit of each terminal.
Indicates N / OFF. Terminals in the group, including the host terminal, know the time when the packet is sent,
The reception is performed for a certain time at a time corresponding to the preamble portion of the packet. This intermittent reception is performed when a control signal from the network controller 15 turns on the transceiver reception unit 16. At this time, when each terminal detects that there is a transmission packet, the terminal continues the reception state and receives the packet. In the example of FIG. 2, transmission packet detection is performed when the detection output signal of the correlation detection unit 12 exceeds a certain threshold. Since each terminal can perform the receiving operation at such an intermittent time, the transceiver including the RF circuit may be operated only during the intermittent receiving, so that the power consumption can be significantly reduced.

[0015]

Second Embodiment In the first embodiment, when there are a plurality of terminals to be transmitted, transmission packets may collide. Therefore, the time at which each terminal starts transmission is shifted at random, code sense is performed before starting transmission, and transmission is started when there is no transmission packet. CDM
If it is not the A system, carrier sense may be performed.

FIG. 4 is a diagram showing an example of a case where the time at which each terminal starts transmission is shifted, and FIG.
FIG. 4B shows ON / O of the transceiver receiving unit of the receiving station.
FF, FIG. 4C shows ON / OFF of a transceiver receiving unit of a station to be transmitted, and FIG. 4D shows ON / OFF of a transceiver transmitting unit of a station to be transmitted. Now, the transmitting station performs code sensing to transmit in time slot 3 (FIG. 4 (c)), but in this case, there is no transmission packet, so the packet is transmitted at random time intervals (FIG. 4 (c)). c)). The time for randomly shifting the transmission is set before the time for performing the intermittent reception. If it is confirmed that a transmission packet exists when code sense or carrier sense is performed, transmission is attempted in the next time slot.

[0017]

Embodiment 3 FIG. 5 is a diagram for explaining an example in which a time slot is assigned to each terminal in a group, and each terminal performs transmission in a time slot assigned to its own station. When communication is performed within a group, a time slot is assigned to each terminal. In FIG. 5, time slot 1 is assigned to terminal 1, time slot 2 is assigned to terminal 2, and time slot 3 is assigned to terminal 3. Each terminal performs transmission in a time slot assigned to itself.
In FIG. 5, the terminal 2 performs transmission in the assigned time slot 2. As in the first embodiment, the receiving terminal intermittently receives the start portion of the time slot and, when detecting that there is a transmission packet, continues the reception state and receives the packet. Since the time slot to be transmitted by each terminal is fixed, transmission packets do not collide.

[0018]

[Embodiment 4] In a communication within a group, a certain person (terminal A) often makes a presentation. In this case, the terminal that performs transmission in the group is only terminal A. In the third embodiment, since a time slot is assigned to each terminal, the time slot that can be transmitted by the terminal A is (1 / the number of terminals in a group), so that the efficiency of packet transmission deteriorates. Therefore, by switching to a mode in which terminal A can continuously use time slots, packets can be transmitted efficiently. FIG. 6 shows an embodiment of the present invention, in which time slots are continuously allocated to the terminal 1, so that the terminal 1 can continuously transmit packets.

[0019]

According to the first aspect of the present invention, in a wireless network in which wireless terminals belonging to a group arbitrarily constituted by a plurality of wireless terminals perform peer-to-peer distributed network communication, a certain group attempts to start communication. The terminal that is the host of the group first selects a channel to be used in the group, and the host terminal and terminals belonging to the group sense the channel at regular intervals and receive only when a signal is detected. In this state, the intermittent reception is performed at regular time intervals, so that the power consumption of the transceiver can be significantly reduced. Therefore, the operation time of the battery-powered wireless terminal can be significantly increased. Can be.

According to a second aspect of the present invention, in the mobile network system according to the first aspect, packet transmission is performed by randomly shifting a transmission start time within a certain fixed time. In addition, by shifting the transmission start time, collision of transmission packets can be eliminated.

According to a third aspect of the present invention, in the mobile network system of the first aspect, a time slot is allocated to each terminal in the group, and each terminal performs transmission in the time slot allocated to its own station. In addition to the effects of the invention of claim 1, by allocating a time slot to each terminal, collision of transmission packets is eliminated,
Reliable transmission can be performed.

According to a fourth aspect of the present invention, in the mobile network system of the first aspect, a mode is provided in which a certain terminal can transmit in a continuous time slot. When a certain terminal uses continuous time slots, packet transmission can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a wireless local area network for a mobile network to which the present invention is applied.

FIG. 2 is a diagram illustrating an example of a terminal that performs CDMA.

FIG. 3 is a diagram for explaining an example in which packet transmission is performed at regular intervals (every time slot).

FIG. 4 is a diagram for explaining an example of a case where transmission is performed by randomly shifting the transmission time of each terminal.

FIG. 5 is a diagram illustrating an example of a case where a time slot is assigned to each terminal and a packet is transmitted.

FIG. 6 is a diagram illustrating an example of a case where a time slot is continuously allocated to a certain end and transmitted.

[Explanation of symbols]

1, 2, 3 ... terminal, 11 ... spreading code generator, 12 ... correlation detector, 13 ... channel controller, 14 ... computer body, 15 ... network controller, 16 ...
Transceiver, 17 ... antenna.

Claims (4)

[Claims] 1. A wireless network in which wireless terminals belonging to a group arbitrarily configured by a plurality of wireless terminals perform peer-to-peer distributed network communication. A terminal first selects a channel to be used in a group, and the host terminal and terminals belonging to the group sense the channel at fixed time intervals, and are in a reception state only when a signal is detected. Mobile network system. 2. The mobile network system according to claim 1, wherein packet transmission is performed by randomly shifting a transmission start time within a certain fixed time. 3. The mobile network system according to claim 1, wherein a time slot is allocated to each terminal in the group, and each terminal performs transmission in the time slot allocated to the mobile station. 4. The mobile network system according to claim 1, wherein said mobile network system has a mode in which a certain terminal can transmit in a continuous time slot.