WO2007148871A1 - Asymmetric relay communication system between up-and down-links - Google Patents
Asymmetric relay communication system between up-and down-links Download PDFInfo
- Publication number
- WO2007148871A1 WO2007148871A1 PCT/KR2007/002081 KR2007002081W WO2007148871A1 WO 2007148871 A1 WO2007148871 A1 WO 2007148871A1 KR 2007002081 W KR2007002081 W KR 2007002081W WO 2007148871 A1 WO2007148871 A1 WO 2007148871A1
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- WIPO (PCT)
- Prior art keywords
- terminal
- central station
- terminals
- communication system
- layer
- Prior art date
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W8/00—Network data management
- H04W8/22—Processing or transfer of terminal data, e.g. status or physical capabilities
- H04W8/24—Transfer of terminal data
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
- H04W84/22—Self-organising networks, e.g. ad-hoc networks or sensor networks with access to wired networks
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/24—Cell structures
- H04W16/30—Special cell shapes, e.g. doughnuts or ring cells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Definitions
- the present invention relates to a communication system between a central station and a plurality of terminals and, more particularly, to an asymmetric relay communication system between up-and down-links that is configured to minimize power consumption of the terminals and provide smooth and reliable communications between the central station and the terminals.
- the existing communication systems are configured in such a manner that a plurality of terminals is connected to a central station or local station and the central station or base station is coupled to another central station or base station through a communication network.
- the use of the central station or base station is mainly applied to a satellite communication system or a mobile communication system that uses wireless terminals.
- the central stations or base stations are established generally in predetermined positions.
- the terminal since the terminal is configured so that a user can carry, the size, weight and power consumption become issues. To this end, the terminal requires a high efficiency battery and a low power consumption system, which cause an increase in the manufacturing cost.
- an object of the present invention is to provide a communication system that can minimize power consumption of terminals.
- Another object of the present invention is to provide a communication system that can reduce the size and price of the terminal by simplifying the configuration of the terminal.
- an asymmetric relay communication system between a central station and a plurality of terminals in accordance with a first aspect of the present invention
- the central station comprises a first RF module for wireless communications with the terminals, a network connection unit for the connection with a communication network, and a first control unit controlling the overall system
- the terminal comprises a second RF module for wireless communications with the central station, a sensor unit detecting an abnormal state of a place where the terminal is installed, a battery supplying operational power, and a second control unit controlling the operation of the terminal
- the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
- an asymmetric relay communication system between a central station and a plurality of terminals in accordance with a second aspect of the present invention, wherein the central station transmits a frequency signal with an intensity that all the terminals can receive, and wherein the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
- the central station transmits layer information to the terminal and transmits a frequency signal with an intensity corresponding to the layer information during the transmission of the layer information, and the terminal sets its layer information based on the most upper value of the layer information received.
- the terminal has an identification number and the central station identifies the terminal based on the identification number of the terminal. Additionally, the central station performs a process of transmitting the layer information in a predetermined time unit.
- the central station checks the abnormal state of the terminals periodically. Furthermore, the terminal having received the up-link signal of the lower layer performs a retransmission process after a predetermined standby time.
- the standby time is determined randomly. Additionally, if an up-link signal from a terminal in the same layer is received during the standby time, the terminal terminates the retransmission process.
- FIGs . 1 and 2 are diagrams illustrating a basic concept of the present invention
- Fig. 3 is a block diagram showing an example of a central station 10 configuration in Fig. 2;
- Fig. 4 is a block diagram showing an example of a terminal 20 configuration in Fig. 2;
- Fig. 5 is a diagram illustrating an operation of transmitting layer information to terminals 20;
- Figs . 6a to 6f are diagram illustrating an operation of a communication system in accordance with the present invention.
- Fig. 1 shows that a plurality of terminals 20 is wirelessly coupled to a single central station (or base station) 10.
- the single central station 10 has a communication area 30, generally called a cell, and the plural terminals 20 exist in the cell 30.
- the cell 30 is decided within a range in which the communications between the central station 10 and the terminals 20 are made smoothly.
- the central station 10 and the terminals 20 are communicated with each other through a down-link that transmits data from the central station 10 to the terminals 20 and an up-link that transmits data from the terminals to the central station 10.
- the central station 10 since the central station 10 is established irrespective of the position and receives a stable operational power, the central station 10 has no problem in transmitting the down-link signal with an intensity that can cover the whole cell 30. Meanwhile, the terminal 20 has limitations in the size thereof and the operational power. Accordingly, a terminal 20-1 located adjacent to the central station 10 can transmit an up-link signal with a low radio-field intensity, whereas, a terminal 20-2 located far away from the central station 10 should transmit an up-link signal with a relatively high radio- field intensity. Accordingly, the terminal 20-2 requires a high performance battery and high efficiency elements for smooth communications with the central station 10.
- all the terminals 20 require such high performance battery and high efficiency elements, which cause an increase in the manufacturing cost of the terminal 20.
- Fig. 2 is a diagram illustrating the basic concept of the present invention.
- the cell 30 is divided into first to third layers A, B and C based on the central station 10. These layers A, B and C are divided on the basis of the distance from the central station 10, more strictly, on the basis of the intensity of the down-link signal transmitted from the central station 10 to the terminal 20 according to communication environments.
- the number of layers divided from the cell 30 can be set arbitrarily.
- the down-link signal is transmitted from the central station 10 to the terminal 20 in the same manner as the conventional system. That is, the central station 10 transmits the down-link signal with an intensity that can cover the whole cell 30.
- the up-link signal is transmitted from the terminal 20 to the central station 10 in a relay manner. That is, a terminal 20-C existing in the third layer C transmits an up-link signal to a terminal 20-B in the second layer B that is an upper layer than the third layer C and, subsequently, the corresponding signal is transmitted through a terminal 20-A in the first layer A to the central station 10.
- the communication system described above can be effectively applied to a security system, surveillance system, management system and the like, in which the up-link signal is generated only during a specific event.
- the configuration and operation of the communication system shown in Fig. 2 will be described in more detail.
- Fig. 3 shows a concrete configuration of the central station 10 of Fig. 2.
- the configuration of the central station 10 shown in Fig. 3 is just an exemplary example and can be readily modified by one of ordinary skill in the art in accordance with an object to which the communication system of the present invention is applied.
- the central station 10 comprises a control unit 11, a network connection unit 12, an RF module 13, an antenna 14, a memory 15 and a display unit 16.
- the control unit 11 controls the central station 10 and the overall operation of the communication system. The operation of the control 11 will be described in detail later.
- the network connection unit 12 connects the central station 10 to another communication network.
- the central station 10 may be connected to various communication networks such as an exchange network, a packet network such as Internet, a mobile communication network, a satellite communication network and the like, if necessary. Accordingly, an appropriate network connection unit 12 is used in accordance with the above circumstances .
- the control unit 11 is coupled to the communication network through the network connection unit 12 to report state information of the communication system to a remote manager.
- the RF module 13 is an ordinary one.
- the RF module 13 modulates a down-link message transmitted from the control unit 11 to the terminal 20 into an RF signal to transmit the RF signal through the antenna 14 and demodulates an up-link signal received from the terminal 20 through the antenna 14 to apply the converted signal to the control unit 11.
- the RF module 13 appropriately adjusts the intensity of the down-link signal output through the antenna 14 according to the control of the control unit 11.
- the memory 15 stores management information including identification information of the terminal 20.
- the display unit 16 displays the state information of the central station 10 and the other terminal 20.
- Fig. 4 shows a concrete configuration of the terminal 20 of Fig. 2.
- the terminal 20 shown in Fig. 4 is just an applicable example and can be readily modified by one of ordinary skill in the art in accordance with an object to which the communication system of the present invention is applied.
- the terminal 20 comprises a control unit 21, a battery 22, a power unit 23, a memory 24, a sensor unit 25, an RF module 26 and an antenna 27.
- the control unit 21 controls the overall operation of the terminal and performs a communication function with the central station 10 in accordance with a predetermined algorithm.
- the algorithm performed by the control unit 21 will be described in detail later.
- the battery 22 supplies electric power required for the operation of the terminal.
- the power unit 23 supplies operational power required by respective circuit units of the terminal based on the voltage of the battery 22. Especially, if the voltage level of the battery 22 is reduced below a predetermined level, the power unit 23 applies corresponding state information to the control unit 21.
- the power unit 23 is an ordinary one, and the present invention does not require a specific configuration.
- the sensor unit 25 performs a surveillance function of the terminal 20.
- the sensor unit 25 may be any one selected from the group consisting of a heat detecting sensor for monitoring fire, a far infrared sensor for detecting a presence of a foreign object, a sensor for detecting gas leakage, a sensor for detecting opening of a door and the like.
- the RF module 26 converts au up-link message applied from the control unit 21 into an RF signal to transmit the RF signal through the antenna 27 and converts an RF signal received through the antenna 27 from the central station 10 or from the other terminal 20 into an electrical signal to apply the converted signal to the control unit 21.
- the central station 10 performs a broadcasting function for setting layers of the respective terminals 20, a system check (state report request) function for checking an abnormal state of the terminal 20, an abnormality report function for reporting a state of the terminal 20 in which an event occurs to a manager.
- the control unit 11 of the central station 10 transmits information for setting a layer of a terminal 20 through the RF module 13 and the antenna 14. Especially, when transmitting layer information, the control unit 11 controls the RF module 13 to adjust the intensity of the RF signal transmitted through the antenna 14 to a level corresponding to the layer information.
- Fig. 5 shows transmission intensities of the layer information transmitted step of step when setting the layers of the terminals 20.
- the central station 10 sets the intensity of the RF signal appropriately, i.e., at TX #1 so that only the terminal 20-A existing in the first layer A may receive the corresponding layer information.
- the control unit 11 increases the output intensities of the RF module 13 step by step to set the transmission intensity at TX #2 and TX #3 and transmits layer information on the second and third layers B and C corresponding to the output intensities.
- the transmission of the layer information may be performed in the sequential order from the first layer A to the third layer C or in the reverse order. Such broadcasting is performed repeatedly in a predetermined time unit.
- the terminal 20 of Fig. 4 stores the layer information including the corresponding message. And the terminal 20 compares layer information received later with the previously received layer information to set its layer based on the layer information of the most upper layer.
- the terminal 20-B existing in the second layer B receives the second and third layer information and compares both the layer information to set its layer based on the second layer information that is upper than itself.
- the layer set information is stored in the memory 24 and continuously used until the next broadcasting.
- System check state report request
- the system check is performed in point-to-point communications between the central station 10 and the terminal 20.
- the terminals 20 have an identification number allotted when manufacturing, respectively, and the terminal 20 newly included in a specific central station 10 transmits its identification number and information to the central station 10 to make an entry. Then, the central station 10 manages the identification numbers for all the terminals 20 in the cell based on the information transmitted from the terminals 20.
- the central station 10 transmits an inquiry message inquiring about the terminal state to the terminal 20 and then the terminal 20 makes a reply message to the inquiry message and transmits the reply message to the central station 10.
- the process of transmitting the reply message from the terminal 20 to the central station 10 is performed in the same manner as that used in an abnormality report process to be described below.
- the central station 10 reports such a terminal to the manager through the network connection unit 12 so as to cope with the abnormal state. 3. Abnormality report
- the terminal 20 reports such an event to the central station 10.
- the event includes a report made in a case where the system has a problem in the battery, sensor, etc., a report made in a case where an abnormality is detected by the sensor, a periodical state report, and the like.
- the control unit 21 of the corresponding terminal 5C makes a message for reporting such an abnormal state and transmits the same through the RF module 26 and the antenna 27.
- the message transmitted from the terminal 5C i.e., the uplink signal includes the layer information and identification number of the corresponding terminal 5C.
- the terminal 20 and the central station 10 transmit a flag signal before transmitting any information. With the use of such a flag signal, it is possible to reduce power consumption of the respective terminals 20 effectively.
- the control unit 21 should set the terminal 20 in a power saving state generally and then check whether the flag signal is received by setting the terminal in a normal state every predetermined time. If the flag signal is received, the control unit 21 may set the corresponding terminal 20 in the operational state.
- the up-link signal from the specific terminal 5C of Fig. ⁇ a is transmitted to only the terminals in a predetermined area adjacent to the specific terminal 5C.
- the terminals having received the up-link signal transmitted from the terminal 5C include the terminals in the same layer as the corresponding terminal 5C, the terminals in the upper layer than the corresponding the terminal 5C, and the terminals in the lower layer than the corresponding terminal 5C, not depicted in the figure.
- the terminal in the same or lower layer as or than the terminal 5C, if the layer information of the message received from the other terminal is the same or upper as or than its layer information, it disregards the corresponding message and is converted into the power saving state.
- the terminal having received the same performs a process of transmitting the same to the terminals in the upper layer than itself.
- the terminals marked in black in Fig. 6c denote the terminals in the upper layer that have received the up-link signal from the terminal 5C.
- the terminal in the second layer B that has received the up-link signal from the terminal 5C in the lower layer generates a random value by operating a random function algorithm and maintains a standby state for a time corresponding to the random value generated.
- the reason for such a time delay of the random value is to prevent that the terminals having received the up-link signal transmit the up-link signal at the same time.
- the terminals having received the up-link signal check whether a frequency channel is used by the other terminal based on the message received through the RF module 26. At this time, if the other terminal uses the frequency signal for the corresponding time, the terminal recognizes that the up-link signal received this time has been transmitted to the upper layer by the other terminal and terminates the process.
- the corresponding terminal adds its layer information and identification number to the message received from the terminal 5C in the lower layer to generate a new up-link signal and transmits the same through the RF module 26 and the antenna 27.
- the terminal having transmitted the uplink signal is a terminal 5B
- the up-link signal from the corresponding terminal 5B is transmitted only to the terminals in a predetermined area adjacent to the terminal 5B as shown in Fig. 6d.
- the terminal 5C in the lower layer that has transmitted the up-link signal to the terminal 5B confirms that the up-link signal that itself transmits is being delivered normally based on the message received from the terminal 5B. That is, the terminal in the lower layer that has transmitted the up-link signal recognizes the transmission signal of the upper layer as a first acknowledgement message.
- the terminals in the first layer A that have received the up-link signal from the terminal 5B in the second layer B generate the up-link signals through the same process and transmit the same to the central station 10, and the terminal 5B in the second layer B recognizes the up-link signal transmitted from the terminal 5A in the first layer A as a first acknowledgement message.
- the control unit 11 transmits a reply message acknowledging receipt of the corresponding message. Such a reply message is transmitted with an intensity that all the terminals in the cell 30 can receive. Then, after checking an abnormal state of the terminal, the control unit 11 reports the same to the manager through the network connection unit 12.
- the terminal 5C if the reply message is received from the central station 10, i.e., if a second acknowledgement message is received, the terminal 5C having reported the abnormality terminates the abnormality state report. However, if no first acknowledgement message is received for a predetermined time after transmitting the up-link signal, or if no second acknowledgement message is received for a predetermined time after receiving the first acknowledgement message, the terminal 5C judges that there is a problem in transmitting the up-link signal and performs the above operation repeatedly.
- the down-link from the central station 10 to the terminal 20 is performed in the same manner as the conventional system.
- the up-link signal transmitted from the terminal 20 to the central station 10 is performed in the relay manner in which the up-link signal passes through the plural terminals 20. Accordingly, it is possible to set the intensity of the up-link signal that the terminal transmits at a lower level that the terminals in the upper layer can receive, thus reducing the power consumption of the terminals and further lowering element specifications . Accordingly, it is possible to simplify the configuration of the terminal and thereby manufacture the terminal at low cost.
- the identification number of the terminal 20 is automatically registered with the central station 10 using the up-link in performing the point-to-point communications between the central station 10 and the terminal 20, it is possible that the manager sets the identification number of the terminal in advance in the central station 10. Moreover, it is possible to perform the process of registering the identification of the terminal 20 automatically in such a manner that the central station 10 sets the layer information for the terminal 20 and then demands the terminal 20 to register the identification number in a broadcasting manner.
- the present invention in configuring a communication network between a single central station or base station and a plurality of terminals, the present invention can minimize the power consumption of the terminals and simplify the configuration of the terminal, thus reducing the manufacturing cost. Moreover, the present invention can be effectively applied to security and disaster prevention systems using a plurality of wireless terminals. Furthermore, the present invention can be applied to a communication system in which the frequency of up-link data transmission from the terminals is very low under communication environments where high-density terminals exist in a broad cell and a single central station should take charge of the terminals.
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Abstract
The present invention has an asymmetric structure in which a down-link signal from a central station to terminals and an up-link signal from the terminals to the central station are transmitted through paths different from each other. Especially, the present invention adopts a relay data transmission in a process of transmitting the up-link signal in which the up-link signal from a terminal in a lower layer is received by a terminal in an upper layer and then the signal is transmitted to the next upper layer. Moreover, the layer of the terminal (20) is set based on layer information transmitted from the central station (10). The central station (10) adjusts the intensity of a radio signal carrying the layer information at a level suitable for the layer and transmits the signal, and the terminal (20) having received such a signal sets its layer based on the layer information received from the central station (10).
Description
[DESCRIPTION]
[invention Title]
ASYMMETRIC RELAY COMMUNICATION SYSTEM BETWEEN UP-AND DOWN-LINKS
[Technical Field]
The present invention relates to a communication system between a central station and a plurality of terminals and, more particularly, to an asymmetric relay communication system between up-and down-links that is configured to minimize power consumption of the terminals and provide smooth and reliable communications between the central station and the terminals.
[Background Art]
With the rapid development of communication techniques, various types of communication systems have been developed and widely used. Most communication systems connect terminals with each other through wire or wireless communication networks to provide data communications between the terminals. The existing communication systems are configured in such a manner that a plurality of terminals is connected to a central station or local station and the central station or base station is coupled to another central station or base station through a
communication network. Especially, the use of the central station or base station is mainly applied to a satellite communication system or a mobile communication system that uses wireless terminals. In configuring a communication network by connecting the central station or base station to the plural terminals through a wireless interface, the central stations or base stations are established generally in predetermined positions. Accordingly, there is no problem in the size of the stations and in supplying necessary electric power to the stations. However, since the terminal is configured so that a user can carry, the size, weight and power consumption become issues. To this end, the terminal requires a high efficiency battery and a low power consumption system, which cause an increase in the manufacturing cost.
Accordingly, it is necessary to minimize the power consumption and reduce the manufacturing cost of the terminal .
[Disclosure] [Technical Problem]
Accordingly, the present invention has been contrived to solve the above-described drawbacks, and an object of the present invention is to provide a communication system that
can minimize power consumption of terminals.
Moreover, another object of the present invention is to provide a communication system that can reduce the size and price of the terminal by simplifying the configuration of the terminal.
[Technical Solution]
To accomplish the above objects of the present invention, there is provided an asymmetric relay communication system between a central station and a plurality of terminals in accordance with a first aspect of the present invention, wherein the central station comprises a first RF module for wireless communications with the terminals, a network connection unit for the connection with a communication network, and a first control unit controlling the overall system, wherein the terminal comprises a second RF module for wireless communications with the central station, a sensor unit detecting an abnormal state of a place where the terminal is installed, a battery supplying operational power, and a second control unit controlling the operation of the terminal, and wherein the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
Moreover, to accomplish the above objects of the present invention, there is provided an asymmetric relay communication system between a central station and a plurality of terminals in accordance with a second aspect of the present invention, wherein the central station transmits a frequency signal with an intensity that all the terminals can receive, and wherein the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
Furthermore, the central station transmits layer information to the terminal and transmits a frequency signal with an intensity corresponding to the layer information during the transmission of the layer information, and the terminal sets its layer information based on the most upper value of the layer information received.
In addition, the terminal has an identification number and the central station identifies the terminal based on the identification number of the terminal. Additionally, the central station performs a process of transmitting the layer information in a predetermined time unit.
Moreover, the central station checks the abnormal state of the terminals periodically. Furthermore, the terminal having received the up-link
signal of the lower layer performs a retransmission process after a predetermined standby time.
In addition, the standby time is determined randomly. Additionally, if an up-link signal from a terminal in the same layer is received during the standby time, the terminal terminates the retransmission process.
[Description of Drawings]
Figs . 1 and 2 are diagrams illustrating a basic concept of the present invention;
Fig. 3 is a block diagram showing an example of a central station 10 configuration in Fig. 2;
Fig. 4 is a block diagram showing an example of a terminal 20 configuration in Fig. 2; Fig. 5 is a diagram illustrating an operation of transmitting layer information to terminals 20; and
Figs . 6a to 6f are diagram illustrating an operation of a communication system in accordance with the present invention.
[Mode for Invention]
Hereinafter, preferred embodiments in accordance with the present invention will be described with reference to the accompanying drawings . The preferred embodiments are provided so that those skilled in the art can sufficiently
understand the present invention, but can be modified in various forms and the scope of the present invention is not limited to the preferred embodiments.
First, the concept of the present invention will be described as follows.
Fig. 1 shows that a plurality of terminals 20 is wirelessly coupled to a single central station (or base station) 10. As shown in the figure, the single central station 10 has a communication area 30, generally called a cell, and the plural terminals 20 exist in the cell 30. As well known in the art, the cell 30 is decided within a range in which the communications between the central station 10 and the terminals 20 are made smoothly.
The central station 10 and the terminals 20 are communicated with each other through a down-link that transmits data from the central station 10 to the terminals 20 and an up-link that transmits data from the terminals to the central station 10.
As described above, since the central station 10 is established irrespective of the position and receives a stable operational power, the central station 10 has no problem in transmitting the down-link signal with an intensity that can cover the whole cell 30. Meanwhile, the terminal 20 has limitations in the size thereof and the operational power. Accordingly, a terminal 20-1 located
adjacent to the central station 10 can transmit an up-link signal with a low radio-field intensity, whereas, a terminal 20-2 located far away from the central station 10 should transmit an up-link signal with a relatively high radio- field intensity. Accordingly, the terminal 20-2 requires a high performance battery and high efficiency elements for smooth communications with the central station 10. Here, since it is difficult to produce the terminals 20-1 and 20-2 differentially, all the terminals 20 require such high performance battery and high efficiency elements, which cause an increase in the manufacturing cost of the terminal 20.
Fig. 2 is a diagram illustrating the basic concept of the present invention. In the figure, the cell 30 is divided into first to third layers A, B and C based on the central station 10. These layers A, B and C are divided on the basis of the distance from the central station 10, more strictly, on the basis of the intensity of the down-link signal transmitted from the central station 10 to the terminal 20 according to communication environments. Of course, the number of layers divided from the cell 30 can be set arbitrarily.
The down-link signal is transmitted from the central station 10 to the terminal 20 in the same manner as the conventional system. That is, the central station 10
transmits the down-link signal with an intensity that can cover the whole cell 30.
Meanwhile, the up-link signal is transmitted from the terminal 20 to the central station 10 in a relay manner. That is, a terminal 20-C existing in the third layer C transmits an up-link signal to a terminal 20-B in the second layer B that is an upper layer than the third layer C and, subsequently, the corresponding signal is transmitted through a terminal 20-A in the first layer A to the central station 10.
Like this, it is possible to transmit the up-link signal with a low electric power even in case of the terminal 20-C located far away from the central station 10, thus simplifying the configuration of the terminal 20 and reducing the manufacturing cost.
The communication system described above can be effectively applied to a security system, surveillance system, management system and the like, in which the up-link signal is generated only during a specific event. Next, the configuration and operation of the communication system shown in Fig. 2 will be described in more detail.
Fig. 3 shows a concrete configuration of the central station 10 of Fig. 2. The configuration of the central station 10 shown in Fig. 3 is just an exemplary example and
can be readily modified by one of ordinary skill in the art in accordance with an object to which the communication system of the present invention is applied.
In the figure, the central station 10 comprises a control unit 11, a network connection unit 12, an RF module 13, an antenna 14, a memory 15 and a display unit 16.
The control unit 11 controls the central station 10 and the overall operation of the communication system. The operation of the control 11 will be described in detail later.
The network connection unit 12 connects the central station 10 to another communication network. The central station 10 may be connected to various communication networks such as an exchange network, a packet network such as Internet, a mobile communication network, a satellite communication network and the like, if necessary. Accordingly, an appropriate network connection unit 12 is used in accordance with the above circumstances . The control unit 11 is coupled to the communication network through the network connection unit 12 to report state information of the communication system to a remote manager. The RF module 13 is an ordinary one. The RF module 13 modulates a down-link message transmitted from the control unit 11 to the terminal 20 into an RF signal to transmit the RF signal through the antenna 14 and demodulates an up-link
signal received from the terminal 20 through the antenna 14 to apply the converted signal to the control unit 11. Especially, the RF module 13 appropriately adjusts the intensity of the down-link signal output through the antenna 14 according to the control of the control unit 11.
The memory 15 stores management information including identification information of the terminal 20. The display unit 16 displays the state information of the central station 10 and the other terminal 20. Fig. 4 shows a concrete configuration of the terminal 20 of Fig. 2. The terminal 20 shown in Fig. 4 is just an applicable example and can be readily modified by one of ordinary skill in the art in accordance with an object to which the communication system of the present invention is applied.
In the figure, the terminal 20 comprises a control unit 21, a battery 22, a power unit 23, a memory 24, a sensor unit 25, an RF module 26 and an antenna 27.
The control unit 21 controls the overall operation of the terminal and performs a communication function with the central station 10 in accordance with a predetermined algorithm. The algorithm performed by the control unit 21 will be described in detail later.
The battery 22 supplies electric power required for the operation of the terminal. The power unit 23 supplies
operational power required by respective circuit units of the terminal based on the voltage of the battery 22. Especially, if the voltage level of the battery 22 is reduced below a predetermined level, the power unit 23 applies corresponding state information to the control unit 21. The power unit 23 is an ordinary one, and the present invention does not require a specific configuration.
The sensor unit 25 performs a surveillance function of the terminal 20. The sensor unit 25 may be any one selected from the group consisting of a heat detecting sensor for monitoring fire, a far infrared sensor for detecting a presence of a foreign object, a sensor for detecting gas leakage, a sensor for detecting opening of a door and the like. The RF module 26 converts au up-link message applied from the control unit 21 into an RF signal to transmit the RF signal through the antenna 27 and converts an RF signal received through the antenna 27 from the central station 10 or from the other terminal 20 into an electrical signal to apply the converted signal to the control unit 21.
Next, the operation of the system configured as described above will be described.
First, the central station 10 performs a broadcasting function for setting layers of the respective terminals 20, a system check (state report request) function for checking
an abnormal state of the terminal 20, an abnormality report function for reporting a state of the terminal 20 in which an event occurs to a manager.
Here, the broadcasting function and system check function are performed repeatedly in a predetermined time unit, and the abnormality report function is carried out only if an event occurs from a specific terminal 20. 1. Broadcasting The control unit 11 of the central station 10 transmits information for setting a layer of a terminal 20 through the RF module 13 and the antenna 14. Especially, when transmitting layer information, the control unit 11 controls the RF module 13 to adjust the intensity of the RF signal transmitted through the antenna 14 to a level corresponding to the layer information.
Fig. 5 shows transmission intensities of the layer information transmitted step of step when setting the layers of the terminals 20. In the figure, to transmit the layer information corresponding to the first layer A, the central station 10 sets the intensity of the RF signal appropriately, i.e., at TX #1 so that only the terminal 20-A existing in the first layer A may receive the corresponding layer information. Like this, only the terminal 20-A located in the first layer A may receive the radio signal transmitted from the central station 10.
After transmitting the layer information on the first layer as described above, the control unit 11 increases the output intensities of the RF module 13 step by step to set the transmission intensity at TX #2 and TX #3 and transmits layer information on the second and third layers B and C corresponding to the output intensities. Of course, the transmission of the layer information may be performed in the sequential order from the first layer A to the third layer C or in the reverse order. Such broadcasting is performed repeatedly in a predetermined time unit.
Meanwhile, if a broadcasting message is received from the central station 10 through the RF module 26, the terminal 20 of Fig. 4 stores the layer information including the corresponding message. And the terminal 20 compares layer information received later with the previously received layer information to set its layer based on the layer information of the most upper layer.
For example, the terminal 20-B existing in the second layer B receives the second and third layer information and compares both the layer information to set its layer based on the second layer information that is upper than itself. The layer set information is stored in the memory 24 and continuously used until the next broadcasting. 2. System check (state report request) The system check is performed in point-to-point
communications between the central station 10 and the terminal 20. The terminals 20 have an identification number allotted when manufacturing, respectively, and the terminal 20 newly included in a specific central station 10 transmits its identification number and information to the central station 10 to make an entry. Then, the central station 10 manages the identification numbers for all the terminals 20 in the cell based on the information transmitted from the terminals 20. The central station 10 transmits an inquiry message inquiring about the terminal state to the terminal 20 and then the terminal 20 makes a reply message to the inquiry message and transmits the reply message to the central station 10. The process of transmitting the reply message from the terminal 20 to the central station 10 is performed in the same manner as that used in an abnormality report process to be described below.
If there exists a terminal 20 that does not make reply to the inquiry message, the central station 10 reports such a terminal to the manager through the network connection unit 12 so as to cope with the abnormal state. 3. Abnormality report
If a specific event occurs in the corresponding system, the terminal 20 reports such an event to the central station 10. Here, the event includes a report made in a case where
the system has a problem in the battery, sensor, etc., a report made in a case where an abnormality is detected by the sensor, a periodical state report, and the like.
Next, an example of a process in which the terminal 20-C in the third layer C performs the abnormality report to the central station 10 will be described.
As shown in Fig. βa, when an abnormality occurs in a terminal 5C existing in the third layer C, the control unit 21 of the corresponding terminal 5C makes a message for reporting such an abnormal state and transmits the same through the RF module 26 and the antenna 27. At this time, the message transmitted from the terminal 5C, i.e., the uplink signal includes the layer information and identification number of the corresponding terminal 5C. Moreover, it is desirable that the terminal 20 and the central station 10 transmit a flag signal before transmitting any information. With the use of such a flag signal, it is possible to reduce power consumption of the respective terminals 20 effectively. That is, since the terminal is operated by electric power of the battery 22, if the terminal is set in an operational state at all times, the electric power of the battery 22 is likely to be exhausted in a short time. Accordingly, it is preferable that the control unit 21 should set the terminal 20 in a power saving state generally
and then check whether the flag signal is received by setting the terminal in a normal state every predetermined time. If the flag signal is received, the control unit 21 may set the corresponding terminal 20 in the operational state.
Meanwhile, since the transmission signal intensities of the respective terminals 20 transmitted through the RF modules 26 are set below a predetermined level as described above, the up-link signal from the specific terminal 5C of Fig. βa is transmitted to only the terminals in a predetermined area adjacent to the specific terminal 5C.
The terminals having received the up-link signal transmitted from the terminal 5C include the terminals in the same layer as the corresponding terminal 5C, the terminals in the upper layer than the corresponding the terminal 5C, and the terminals in the lower layer than the corresponding terminal 5C, not depicted in the figure.
First, in case of the terminal in the same or lower layer as or than the terminal 5C, if the layer information of the message received from the other terminal is the same or upper as or than its layer information, it disregards the corresponding message and is converted into the power saving state.
Meanwhile, if the layer information of the received message is lower than its layer information, the terminal
having received the same performs a process of transmitting the same to the terminals in the upper layer than itself. The terminals marked in black in Fig. 6c denote the terminals in the upper layer that have received the up-link signal from the terminal 5C.
In Fig. 6c, the terminal in the second layer B that has received the up-link signal from the terminal 5C in the lower layer generates a random value by operating a random function algorithm and maintains a standby state for a time corresponding to the random value generated. The reason for such a time delay of the random value is to prevent that the terminals having received the up-link signal transmit the up-link signal at the same time.
For such a time delay, the terminals having received the up-link signal check whether a frequency channel is used by the other terminal based on the message received through the RF module 26. At this time, if the other terminal uses the frequency signal for the corresponding time, the terminal recognizes that the up-link signal received this time has been transmitted to the upper layer by the other terminal and terminates the process.
Meanwhile, if the frequency channel is not used by the other terminal during the standby time, the corresponding terminal adds its layer information and identification number to the message received from the terminal 5C in the
lower layer to generate a new up-link signal and transmits the same through the RF module 26 and the antenna 27.
In Fig. 6c, if the terminal having transmitted the uplink signal is a terminal 5B, the up-link signal from the corresponding terminal 5B is transmitted only to the terminals in a predetermined area adjacent to the terminal 5B as shown in Fig. 6d.
Also in case of the terminal in the same or lower layer as or than the terminal 5B, if the layer information of the message received from the other terminal is the same or upper as or than its layer information, it disregards the corresponding message and is converted into the power saving state as described above. However, the terminal 5C in the lower layer that has transmitted the up-link signal to the terminal 5B confirms that the up-link signal that itself transmits is being delivered normally based on the message received from the terminal 5B. That is, the terminal in the lower layer that has transmitted the up-link signal recognizes the transmission signal of the upper layer as a first acknowledgement message.
Subsequently, the terminals in the first layer A that have received the up-link signal from the terminal 5B in the second layer B generate the up-link signals through the same process and transmit the same to the central station 10, and the terminal 5B in the second layer B recognizes the up-link
signal transmitted from the terminal 5A in the first layer A as a first acknowledgement message.
In the central station 10, if an up-link signal is received through the RF module 13, the control unit 11 transmits a reply message acknowledging receipt of the corresponding message. Such a reply message is transmitted with an intensity that all the terminals in the cell 30 can receive. Then, after checking an abnormal state of the terminal, the control unit 11 reports the same to the manager through the network connection unit 12.
Meanwhile, if the reply message is received from the central station 10, i.e., if a second acknowledgement message is received, the terminal 5C having reported the abnormality terminates the abnormality state report. However, if no first acknowledgement message is received for a predetermined time after transmitting the up-link signal, or if no second acknowledgement message is received for a predetermined time after receiving the first acknowledgement message, the terminal 5C judges that there is a problem in transmitting the up-link signal and performs the above operation repeatedly.
As such, the preferred embodiment of the present invention has been described. According to the embodiment described above, the down-link from the central station 10 to the terminal 20 is performed in the same manner as the
conventional system. However, the up-link signal transmitted from the terminal 20 to the central station 10 is performed in the relay manner in which the up-link signal passes through the plural terminals 20. Accordingly, it is possible to set the intensity of the up-link signal that the terminal transmits at a lower level that the terminals in the upper layer can receive, thus reducing the power consumption of the terminals and further lowering element specifications . Accordingly, it is possible to simplify the configuration of the terminal and thereby manufacture the terminal at low cost.
Moreover, the above-described embodiment is an exemplary example of the present invention and the present invention is not limited thereto, rather, it should be understood that various modifications and variations of the present invention can be made thereto by those skilled in the art without departing from the spirit and the technical scope of the present invention as defined by the appended claims .
For example, in the above-described embodiment, although the description has been made in which the identification number of the terminal 20 is automatically registered with the central station 10 using the up-link in performing the point-to-point communications between the
central station 10 and the terminal 20, it is possible that the manager sets the identification number of the terminal in advance in the central station 10. Moreover, it is possible to perform the process of registering the identification of the terminal 20 automatically in such a manner that the central station 10 sets the layer information for the terminal 20 and then demands the terminal 20 to register the identification number in a broadcasting manner.
[industrial Applicability]
As described in detail above, in configuring a communication network between a single central station or base station and a plurality of terminals, the present invention can minimize the power consumption of the terminals and simplify the configuration of the terminal, thus reducing the manufacturing cost. Moreover, the present invention can be effectively applied to security and disaster prevention systems using a plurality of wireless terminals. Furthermore, the present invention can be applied to a communication system in which the frequency of up-link data transmission from the terminals is very low under communication environments where high-density terminals exist in a broad cell and a single central station should take charge of the terminals.
Claims
[Claim 1]
An asymmetric relay communication system between a central station and a plurality of terminals, wherein the central station comprises a first RF module for wireless communications with the terminals, a network connection unit for the connection with a communication network, and a first control unit controlling the overall system, wherein the terminal comprises a second RF module for wireless communications with the central station, a sensor unit detecting an abnormal state of a place where the terminal is installed, a battery supplying operational power, and a second control unit controlling the operation of the terminal, and wherein the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
[Claim 2]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 1, wherein the central station transmits layer information to the terminal and transmits a frequency signal with an intensity corresponding to the layer information during the transmission of the layer information, and wherein the terminal sets its layer information based on the most upper value of the layer information received.
[Claim 3]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 1 or 2, wherein the terminal has an identification number and the central station identifies the terminal based on the identification number of the terminal.
[Claim 4]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 2, wherein the central station performs a process of transmitting the layer information in a predetermined time unit.
[Claim 5]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 1, wherein the central station checks the abnormal state of the terminals periodically.
[Claim 6]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 1, wherein the terminal having received the up-link signal of the lower layer performs a retransmission process after a predetermined standby time.
[Claim 7]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 6, wherein the standby time is determined randomly.
[Claim 8] The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 6, wherein, if an up-link signal from a terminal in the same layer is received during the standby time, the terminal terminates the retransmission process.
[Claim 9]
An asymmetric relay communication system between a central station and a plurality of terminals, wherein the central station transmits a frequency signal with an intensity that all the terminals can receive, and wherein the terminal includes layer information corresponding to communication environments with the central station and receives an up-link signal of a lower layer to retransmit the same.
[Claim 10]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 9, wherein the central station transmits layer information to the terminal and transmits a frequency signal with an intensity corresponding to the layer information during the transmission of the layer information, and wherein the terminal sets its layer information based on the most upper value of the layer information received.
[Claim 111 The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 9, wherein the terminal having received the up-link signal of the lower layer performs a retransmission process after a predetermined standby time.
[Claim 12]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 11, wherein the standby time is determined randomly.
[Claim 13]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 11, wherein, if an up-link signal from a terminal in the same layer is received during the standby time, the terminal terminates the retransmission process.
[Claim 14]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 9, wherein the terminal transmits a flag signal before transmitting the up-link signal.
[Claim 15]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 9, wherein the terminal is set in a power saving mode and in a normal operation mode repeatedly.
[Claim lβ]
The asymmetric relay communication system between a central station and a plurality of terminals as recited in claim 9, wherein the terminal having transmitted the up-link signal to an upper layer retransmits the up-link signal, if no up-link signal from the terminal is detected or if no acknowledgement message is received from the central station.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP07746238.0A EP2036218A4 (en) | 2006-06-19 | 2007-04-27 | Asymmetric relay communication system between up-and down-links |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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KR10-2006-0054879 | 2006-06-19 | ||
KR1020060054879A KR100780803B1 (en) | 2006-06-19 | 2006-06-19 | Asymmetric relay communications system between a up-link and a down-link |
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WO2007148871A1 true WO2007148871A1 (en) | 2007-12-27 |
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PCT/KR2007/002081 WO2007148871A1 (en) | 2006-06-19 | 2007-04-27 | Asymmetric relay communication system between up-and down-links |
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EP (1) | EP2036218A4 (en) |
KR (1) | KR100780803B1 (en) |
WO (1) | WO2007148871A1 (en) |
Cited By (2)
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WO2011014348A1 (en) * | 2009-07-29 | 2011-02-03 | Cisco Technology, Inc. | Low latency mesh network |
JP2016076911A (en) * | 2014-10-09 | 2016-05-12 | トヨタ自動車株式会社 | Radio communication device and communication method |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20110134826A1 (en) | 2009-12-04 | 2011-06-09 | Xiangying Yang | Relay data path architecture for a wireless network |
KR20220046948A (en) | 2020-10-08 | 2022-04-15 | 삼성전자주식회사 | Storage controller, storage system and operating method thereof |
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KR100314860B1 (en) * | 1999-05-11 | 2001-11-17 | 김재영 | Left side sleeve system |
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EP1678879B1 (en) * | 2003-10-17 | 2013-02-27 | TELEFONAKTIEBOLAGET LM ERICSSON (publ) | Method and system for asymmetric dual-mode radio communications |
JP4652846B2 (en) * | 2004-03-11 | 2011-03-16 | パナソニック株式会社 | Communication terminal device and communication relay method |
KR100698249B1 (en) * | 2005-09-13 | 2007-03-22 | 삼성전자주식회사 | Apparatus and method for relaying of neighbor bs information message by relay station in a multi-hop relay broadband wireless access communication system |
KR100891295B1 (en) * | 2005-09-28 | 2009-04-06 | 삼성전자주식회사 | Apparatus and method for advertising the features of relay station in a multi-hop relay broadband wireless access communication system |
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2006
- 2006-06-19 KR KR1020060054879A patent/KR100780803B1/en not_active IP Right Cessation
-
2007
- 2007-04-27 WO PCT/KR2007/002081 patent/WO2007148871A1/en active Application Filing
- 2007-04-27 EP EP07746238.0A patent/EP2036218A4/en not_active Withdrawn
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US5875209A (en) * | 1995-04-06 | 1999-02-23 | Fujitsu Limited | Digital radio system including repeater equipment, end equipment and receiver |
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JP2016076911A (en) * | 2014-10-09 | 2016-05-12 | トヨタ自動車株式会社 | Radio communication device and communication method |
Also Published As
Publication number | Publication date |
---|---|
KR100780803B1 (en) | 2007-11-30 |
EP2036218A1 (en) | 2009-03-18 |
EP2036218A4 (en) | 2014-07-30 |
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