KR20190095126A - Method for service using multiple channel in wireless distributed communication systems - Google Patents

Abstract

The present invention proposes a method efficiently finding and using a service in a synchronous wireless distributed communication environment. In the present invention, the method proposes six types of slots and two types of channels. The method proposes the six types of slots, which are a fixed broadcast slot, a general broadcast slot, a designated broadcast slot, a fixed use slot, a general use slot, and a designated use slot, and the two types of channels, which are a broadcast channel and a use channel.

Description

Service method using multiple channels in wireless distributed communication system {Method for service using multiple channel in wireless distributed communication systems}

The present invention relates to a method for providing a service in a synchronous TDMA system, and more particularly, to a service method using a multi-channel in a synchronous TDMA system.

Discovering services in a distributed communication system requires several steps. In the case of the peer aware communication (PAC) standard, there are steps of synchronization, discovery and relationship. That is, the terminals perform synchronization with each other, and then discover other terminals and discover a service through a relationship.

This procedure is so complex that it is difficult to commercialize in the real market. Accordingly, the present invention proposes a method of quickly discovering a service and accessing a desired service.

To do so, the present invention assumes the environment of Ref. 1 (10-2017-0026778, hereinafter Ref. 1). That is, in a synchronous TDMA system, slots are allocated by distributed terminals through contention. Detailed competition schemes are described in Ref.

In conventional synchronous TDMA, a control station allocates a slot to a terminal. However, since there is no control station for allocating slots in distributed communication in which only terminals exist, the terminals must allocate slots themselves. A representative example of such a system is SOTDMA. However, since the existing SOTDMA allocates empty slots unconditionally without a contention procedure, slot collisions are high in an environment with many terminals. In addition, since it is not known whether a collision has occurred, the allocated slot must be replaced periodically. At this time, in the first invention, distributed terminals compete by synchronous CSMA / CA and CDAD in a contention channel having a different frequency, so that the resource collision probability is extremely low, so that even if tens of thousands use the channel, the resource collision probability is very low.

In this case, the present invention intends to provide a method of quickly discovering a service in a synchronous TDMA environment and accessing a desired service in consideration of the competition method of Reference 1.

An object of the present invention is to propose a method for easily discovering and using a service in a wireless distributed communication system.

In the present invention, six types of slots are proposed, and two types of channels are proposed.

The present invention proposes six types of slots, that is, a fixed broadcast slot, a general broadcast slot, a designated broadcast slot, a fixed use slot, a general use slot, and a designated use slot, and two types of channels, a broadcast channel and a use channel.

The broadcast channel and the use channel may provide a service while interacting closely with each other. In particular, when several other terminals are connected to the service providing terminal, the service terminal transmits information to many terminals at once through the slot of the broadcast channel. Can suggest a way to.

When allocating a lot of used slots, if a slot group is assigned and one slot of the slot group is allocated, all slots of the slot group to which the slot belongs are considered as allocated, and thus a method of allocating many slots at once can be proposed. .

Slot maps may be transmitted to solve hidden node problems in a wireless distributed system. In particular, such a slot map can be broadcasted in a broadcast channel. By not broadcasting a slot map for a broadcast channel but broadcasting a slot map of a useable channel that can be accessed, a method of effectively conceiving a hidden node problem can be proposed.

The configuration and operation of channels and slots can suggest a method that can be effectively used in a synchronous wireless distributed communication system.

According to an embodiment of the present invention, a method for receiving a service from a terminal in a synchronous TDMA distributed system may be provided. In this case, the method in which the terminal is provided with a service may include receiving service information from a service providing terminal using a broadcast slot, discovering a service based on the received service information, and using the found service. . In this case, if the found service is a service available as the service information of the received broadcast slot, the terminal uses the service through the broadcast slot based on the received service information of the broadcast slot, and the broadcast slot received by the found service. If the service information itself is not a service available, the terminal may use the service through the use slot based on the service information.

In addition, according to an embodiment of the present invention, it is possible to provide a terminal receiving a service in a synchronous TDMA distributed system. In this case, the terminal may include a transmitter for transmitting a signal, a receiver for receiving a signal, and a processor for controlling the transmitter and the receiver. At this time, the processor receives the service information from the service providing terminal by using the broadcast slot through the receiving unit, finds the service based on the received service information, and uses the found service, but the broadcast slot received by the found service In the case of a service that can be used as the information itself, the terminal uses the service through the broadcast slot based on the received broadcast slot information, and if the found service is not a service that is available as the information of the received broadcast slot itself, The service may be used through the use slot based on the received service information.

In addition, according to an embodiment of the present invention, a method for providing a service by a terminal in a synchronous TDMA distributed system may be provided. In this case, the method for providing a service by the terminal may include transmitting service information using a broadcast slot to a terminal receiving the service, and providing a service to the terminal receiving the service. In this case, if the service is a service available as the service information of the broadcast slot itself, the terminal provides the service through the broadcast slot based on the service information of the broadcast slot to the terminal receiving the service, the service is the service information of the broadcast slot If the service is not available, the terminal may provide a service through a use slot based on the service information.

In addition, according to an embodiment of the present invention, it is possible to provide a terminal providing a service in a synchronous TDMA distributed system. In this case, the terminal providing the service may include a transmitter for transmitting a signal, a receiver for receiving a signal, and a processor for controlling the transmitter and the receiver. At this time, the processor transmits the service information by using the broadcast slot to the terminal receiving the service through the transmitter, and provides a service to the terminal receiving the service, if the service is a service available as the service information itself of the broadcast slot, The terminal provides a service through the broadcast slot based on the service information of the broadcast slot to the terminal provided with the service, and if the service is not a service available as the service information of the broadcast slot, the terminal selects a used slot based on the service information. Can provide services.

In addition, the following items may be commonly applied to a terminal provided with a service and a terminal providing a service in a synchronous TDMA distributed system.

According to an embodiment of the present invention, when a terminal uses a service through a use slot, the service providing terminal allocates a use slot through slot allocation competition, and uses the slot allocated to the terminal in the allocated use slot of the first frame. The consent request signal for use may be transmitted, and ACK information about the consent request signal received from the terminal may be received in the allocated use slot of the second frame. In this case, the second frame may be the next frame of the first frame.

In addition, according to an embodiment of the present invention, after receiving the ACK information, the service providing terminal transmits the response information to the terminal, but the response information may be transmitted to the plurality of terminals through the broadcast slot.

In addition, according to an embodiment of the present invention, the response information may include at least one or more of ACK, NACK, time, number, order, amount, and availability.

In addition, according to an embodiment of the present invention, when allocating a use slot, specific use slots are used as a use slot group among the use slots of the frame, and the service providing terminal is configured to use any of the slots included in the use slot group. Select one slot to allocate a slot through contention, transmit a used slot group allocation request to the terminal through the assigned slot, and receive an ACK for the slot group allocation request in the next slot of the allocated slot from the terminal. All slots in the used slot group to which one slot belongs may be allocated based on slot clearing.

In addition, according to an embodiment of the present invention, the use slot is allocated based on the slot map, and the slot map may be a map indicating whether the use slots constituting one frame are available.

In addition, according to an embodiment of the present invention, the slot map may include information about available slots based on carrier sensing performed in a contention substitute channel mapped to the channel instead of the channel in which the slots exist.

In addition, according to an embodiment of the present invention, the service providing terminal transmits the slot map information to the terminal along with the agreement request signal for using the allocated use slot, and the terminal can be used at the same time based on the slot map information. An effective slot map indicating a may be created and transmitted to the service providing terminal together with the ACK.

In addition, according to an embodiment of the present invention, the service providing terminal transmits a slot map creation request to the terminal with an agreement request signal for using the assigned slot, the terminal creates a slot map and ACKs the created slot map. And transmit to the service providing terminal, and the service providing terminal creates a valid slot map indicating valid available slots that can be used simultaneously based on the received slot map information of the terminal, and allocates the used slots based on the valid slot map. Can be.

In addition, according to an embodiment of the present invention, the service providing terminal receives the slot map information of the terminal that the terminal broadcasts through the broadcast slot, and displays the valid use slots that can be used simultaneously based on the received slot map information of the terminal. One effective slot map can be created and used slots assigned based on the valid slot map.

In addition, according to an embodiment of the present invention, a broadcast slot may be included in at least one of a mixed channel and a broadcast channel, and a use slot may be included in at least one of a mixed channel and a use channel.

In addition, according to an embodiment of the present invention, a broadcast slot may include at least one of a general broadcast slot, a designated broadcast slot, and a fixed broadcast slot.

According to an embodiment of the present invention, a predetermined specific service of a channel corresponds to fixed broadcast slots among broadcast slots, and when a terminal receives a specific service, the terminal always receives the fixed broadcast slots and specifies A terminal providing a service may be allocated a fixed broadcast slot through competition in a fixed broadcast slot, and may provide a specific service by using the assigned fixed broadcast slot.

In addition, according to an embodiment of the present invention, the service related information transmitted in the broadcast slots may be allocated to the number of slots required for the service, the minimum number of slots required for the service, the maximum number of slots required for the service, use channel, frequency information of the mixed channel and It may include at least one or more of the number of the slot that is occupied by the current slot in the use slot.

In addition, according to an embodiment of the present invention, the use slot may include at least one or more of a general use slot, a designated use slot and a fixed use slot.

In addition, according to an embodiment of the present invention, a broadcast slot may be allocated to a service providing terminal and used.

In addition, according to an embodiment of the present invention, when a broadcast slot is allocated, specific broadcast slots are preset to a broadcast slot group among the broadcast slots of a frame, and the service providing terminal is any one of slots belonging to the broadcast slot group. If a slot of the slot is selected and allocated through competition, all slots of the broadcast slot group to which the allocated slot belongs may be allocated based on slot clearing.

According to the present invention, a service can be easily found and used in a distributed communication system.

According to the present invention, six types of slots and two types of channels can be used.

According to the present invention, six types of slots of a fixed broadcast slot, a general broadcast slot, a designated broadcast slot, a fixed use slot, a general use slot, and a designated use slot, and two types of channels, a broadcast channel and a use channel, can be used.

According to the present invention, a broadcast channel and a use channel can provide a service while closely interacting with each other. In particular, when several other terminals are connected to the service providing terminal, the service terminal is provided to many terminals during the connection through the slots of the broadcast channel. Information can be delivered all at once.

When allocating a number of used slots, a slot group may be designated to allocate one slot of the slot group, so that all the slots of the slot group to which the slot belongs may be allocated and many slots may be allocated at once.

Slot maps may be transmitted to solve hidden node problems in a wireless distributed system. In particular, such a slot map can be broadcasted in a broadcast channel. Broadcasting a slot map of a useable channel that can be accessed instead of a slot map for a broadcast channel can effectively solve the hidden node problem.

The configuration and operation of channels and slots can be effectively used in a synchronous wireless distributed communication system.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a configuration diagram of a broadcast slot, a used slot, and a mixed slot.
2 is a diagram illustrating an allocation procedure of a use slot.
3 is an exemplary configuration diagram of a broadcast channel, a use channel, and a mixed channel.
4 is an exemplary diagram of a service provided to a broadcast slot of a broadcast channel.
5 is an exemplary diagram of a field format constituting a broadcast slot.
6 is an exemplary diagram of a field format constituting a use slot.
7 is an exemplary view of configuring a fixed use slot.
8 illustrates an example of interaction between a broadcast channel and a use channel.
9 shows an example of a frame with a slot group.
10 is a flowchart for allocating slot groups.
11 is a flowchart illustrating a method of transmitting a slot map together in slot allocation.
12 is a flowchart illustrating a method of requesting a counterpart slot map together when allocating slots.
FIG. 13 is a flowchart illustrating a method of allocating slots using a slot map broadcast when a slot is allocated.
14 is a block diagram of a terminal device.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, the substantially identical components are represented by the same reference numerals, and thus redundant description will be omitted. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In the following description of embodiments of the present invention, when it is determined that a detailed description of a known structure or function may obscure the gist of the present invention, a detailed description thereof will be omitted. In the drawings, parts irrelevant to the description of the present invention are omitted, and like reference numerals denote like parts.

In the present invention, when a component is "connected", "coupled" or "connected" with another component, it is not only a direct connection, but also an indirect connection in which another component exists in between. It may also include. In addition, when a component "includes" or "having" another component, it means that it may further include another component, without excluding the other component unless otherwise stated. .

In the present invention, the terms "first" and "second" are used only for the purpose of distinguishing one component from other components, and do not limit the order or the importance between the components unless otherwise specified. Accordingly, within the scope of the present invention, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment. It may also be called.

In the present invention, the components distinguished from each other to clearly describe each feature, and does not necessarily mean that the components are separated. That is, a plurality of components may be integrated into one hardware or software unit, or one component may be distributed and formed into a plurality of hardware or software units. Therefore, even if not mentioned otherwise, such integrated or distributed embodiments are included in the scope of the present invention.

In the present disclosure, components described in various embodiments of the present disclosure are not necessarily required components, and some of them may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also included in the scope of the present invention. In addition, embodiments including other components in addition to the components described in the various embodiments are included in the scope of the present invention.

The present invention assumes that all terminals use synchronous TDMA. For example, the terminal may operate based on the TDMA scheme. That is, all the terminals may be synchronized. In addition, as an example, each terminal may occupy slot resources equally. That is, each terminal may occupy slot resources based on the same opportunity. In addition, as an example, each terminal may have an opportunity to occupy different slot resources based on the priority, and is not limited to the above-described embodiment.

In connection with the present invention, the existing CSMA / CA could only be used in an asynchronous communication system. In this case, in the wireless distributed communication system of the present invention, the contention substitute channel may be used so that the CSMA / CA may be used in the synchronization system. For example, the primary channel and the secondary channel may be paired. The original data channel may have a wide bandwidth of several MHz. In this case, the main communication band may be used as the data channel as it is. Competing channels use narrowband signals. A frequency tone can be used as a narrow band signal, and since the frequency tone has a bandwidth of several kHz to several tens of kHz, it has a bandwidth less than 1/100 of the broadband bandwidth. As an example, if the 1MHz band is configured with a 10kHz tone channel and a 990kHz data channel, the maximum data channel utilization is 99% under the assumption that there is no collision. This can be very advantageous when using CSMA / CA in the same band, compared to 50% maximum channel utilization. In this case, as an example, the secondary channel may be allocated immediately adjacent to the primary channel. In addition, as an example, the subchannel may be allocated away from the main channel, and is not limited to the above-described embodiment.

That is, in an environment where a plurality of terminals (e.g. thousands or tens of thousands) of terminals coexist, the channel efficiency of the plurality of terminals may be set differently from that of the data transmission channel, thereby improving frequency efficiency.

In addition, as an example, UEs may compete in a slot before a slot to be used. In more detail, if UE A decides to use slot s of the primary channel, UE A may perform competition in advance in slot s-1, which is a competition agency channel. At this time, UE A may perform carrier sensing to the previous subslot of the selected subslot if the subslot number in the slot of the contention substitute channel is N. If there is no signal detected as a result of the execution, a contention tone signal is transmitted from the selected subslot to the 55th slot, and data is transmitted in slot s of the main channel. In this case, as an example, when there is a signal detected as a result of the execution of the terminal A, the terminal A may determine that it is lost in contention and may not transmit any signal in the tone channel and the main channel. However, the above-described sub slot allocation is only one embodiment and is not limited to a specific number. That is, the terminal allocated the lowest number of subslots may transmit a contention signal after carrier sensing and perform data transmission on the primary channel.

In this case, as an example, the signal of the competition agency channel may use a frequency tone signal, and in this case, the frequency band may be used the least. In this case, hereinafter, the contention signal is assumed to be a tone signal. However, the competition signal may be set differently, and is not limited to the above-described embodiment. Through the above-described competition, terminals selected the same slot can avoid collision. For example, in the above-described situation, the UEs having selected the same slot among 500 could avoid collision again.

In the present invention, slot clearing means that a terminal continuously transmits a contention signal starting from sub-slot 0 in a previous slot s-1 of a contention channel in order to continuously use the slot s without collision. It can mean preventing attempts. That is, it may mean the operation as described above, the following description will be described on the premise.

In addition, as an example, the following means that competition is performed to allocate slots, which may mean that synchronous CSMA / CA is performed on a second channel having a different frequency, similar to the first invention. Also, as an example, CDAD may be additionally performed after performing synchronous CSMA / CA. At this time, if the terminal occupies slot resources, slot clearing is performed. Therefore, other terminals may fail to allocate the slot.

In this case, as an example, an operation for easily discovering a service in a distributed system may be required. To this end, two TDMA slots are described below. For example, one may be a broadcast slot and one may be a use slot.

For example, referring to FIG. 1, a broadcast slot and a use slot may be used. In this case, the broadcast slot is a slot for the terminal to unilaterally broadcast information to the surrounding terminals. That is, there may be no target terminal address for information transmission, or a slot having a target address meaning all terminals and transmitted based on a broadcast scheme.

The use slot may be a slot for the terminal to transmit and receive information with other terminals or terminals. The use slot may mean a specific terminal or a specific terminal group when the information is transmitted, and may be a slot transmitted based on a unicast or groupcast scheme. The broadcast slot may be divided into a general broadcast slot, a designated broadcast slot, and a fixed broadcast slot. In this case, the general broadcast slot may mean a broadcast slot allocated by a normal terminal through competition for information broadcasting. In addition, the designated broadcast slot may mean a broadcast slot allocated in advance so that a predetermined type of terminal can broadcast information. The fixed broadcast slot may mean a broadcast slot in which only predetermined types of terminals may be allocated through competition for information broadcasting.

When the terminal uses the use slot, the terminal may have to compete with other terminals to be allocated the use slot. In addition, as an example, unlike a broadcast slot, in a use slot, there may be a target terminal for obtaining agreement on slot allocation. As an example, when the terminal requests allocation of a use slot through competition, the terminal may transmit a signal for requesting consent for joint use in order to use the slot together with another terminal. Thereafter, the terminal receiving the joint use request may transmit an ACK for this in the slot number assigned by the terminal requesting allocation of the use slot of the next frame. Thereafter, when the terminal requesting the use slot allocation receives the ACK signal, slot allocation between the two terminals may be completed.

More specifically, referring to FIG. 2, the first terminal (terminals 1 and 210) may transmit a use slot allocation request to the second terminal (terminals 2 and 220). In this case, the first terminal 210 may transmit frame 4 through slot 10. Thereafter, the second terminal 220 may transmit the frame 5 in slot 10 in response to the ACK response, and thus, the slot allocation may be completed. Thereafter, the first terminal 210 may exchange data with the second terminal 220 through the use slot. In this case, for example, referring to FIG. 1, a use slot may be divided into a general use slot, a designated use slot, and a fixed use slot. In this case, the general use slot may mean a use slot allocated by a normal terminal through competition in order to transmit and receive information with other terminals or terminals. In addition, the designated use slot may mean a use slot that is pre-allocated so that a predetermined type of terminal can transmit / receive information with other terminals or terminals. The fixed use slot may mean a use slot that can be allocated through a competition for only a predetermined type of terminals to transmit and receive information with other terminals or terminals.

The following describes a method of operating based on a broadcast channel, a use channel, and a mixed channel for service discovery in a distributed system.

More specifically, referring to FIG. 3, the broadcast channel, the use channel, and the mixed channel may be channels having different center frequencies. In this case, each system may have a different number of broadcast channels, a number of channels used, and a number of mixed channels, and the present invention is not limited to the above-described embodiment. At this time, the broadcast channel may be a channel consisting of a broadcast slot as described above. That is, the broadcast slot may include one or more slots among the general broadcast slot, the designated broadcast slot, and the fixed broadcast slot type.

The use channel may be a channel consisting of use slots. In this case, as described above, the use slot may include one or more slots among a general use slot, a designated use slot, and a fixed use slot type.

In addition, the mixed channel may be a channel in which a broadcast slot and a use slot are mixed. For example, the mixed channel may include at least one of a general broadcast slot, a designated broadcast slot, and a fixed broadcast slot. In addition, the mixed channel may further include at least one or more of a general use slot, a designated use slot, and a fixed use slot at the same time. That is, the mixed channel may include at least one slot among the slots included in the broadcast slot and the use slot, and is not limited to the above-described embodiment.

In this case, various services may be periodically broadcast every frame in the broadcast channel. Accordingly, the number of broadcasted services may be equal to or smaller than the number of slots constituting the frame. As an example, one frame is set to 1 second and will be described based on the case of 500 slots. However, this is only one example for convenience of description and is not limited to the above-described embodiment.

More specifically, referring to FIG. 4, it may be a structure of a synchronous TDMA channel designated as a broadcast channel. In this case, the terminals to provide the service may broadcast the service by receiving one or a plurality of slots. For example, FIG. 4 may show an example of a service. For example, a traffic light blinking notification service, a speaker connection service, a shop information notification service, a parking lot information notification service, etc. may be set in one frame, but this is only one example and is not limited to the above-described embodiment.

In this case, in order to distinguish a service, a field indicating a service type may be required in a slot type of a broadcast channel. Hereinafter, a field indicating a service type in a broadcast slot is referred to as a "service field." For example, the service field may be set to 8 bits, the traffic light blinking notification service may be 0x01, the speaker connection service 0x02, and the store connection service 0x03.

For example, referring to FIG. 5, it may represent a field of a broadcast slot. In this case, the field of the service broadcast slot may include at least one of a service field, a source address field, a control field, a data field, and a CRC field. In this case, information on who transmits what service may be represented by a service field and an address field. That is, whether a service is indicated through a service field and who transmits may be indicated through a source address field. In addition, the specific service content may be included in the data field. In addition, the CRC may be a field for checking the integrity of data. In this case, when the terminal receives one broadcast channel frame, it may discover all services in the vicinity. In more detail, as shown in FIG. 4, the broadcast channel may include information on one or more services. When the terminal receives one broadcast channel frame, the terminal may discover all services in the vicinity. In this case, as an example, an operation of discovering a service by receiving one broadcast channel frame is referred to as 'quick search'. However, the above terms are referred to for convenience of description and are not limited to the above names. That is, the same operation may be described in different terms.

In this case, as an example, when the terminal knows the slot position of the traffic light blinking notification service, the terminal may continuously update information by receiving only the corresponding slot from the next frame. For example, as described above, an operation of receiving only a corresponding slot after knowing a slot position of a specific service is referred to as 'fixed repeat reception'. However, the above terms are referred to for convenience of description and are not limited to the above names. That is, the same operation may be described in different terms.

Therefore, the terminal can quickly and easily find a service through quick searching. In addition, the terminal may use the service at low power through fixed repeat reception. That is, the terminal receives only the fixed slot and does not operate at another slot time, thereby reducing power consumption. (Ie, the terminal may turn off the modem at another slot time.)

In addition, when the terminal searches for a service through quick search, power consumption of the terminal may be reduced. Specifically, if a terminal equipped with a distributed communication modem runs an app or a program and simultaneously turns on the distributed modem, it may provide a service immediately after performing a quick search for 1 second frame time, thereby reducing power consumption. . That is, the terminal equipped with the distributed communication modem may be turned off or in the sleep mode of the distributed communication modem at the time when the app or the program is not executed. In the following, this is referred to as "program sync" or "app sync." However, the above terms are referred to for convenience of description and are not limited to the above names. That is, the same operation may be described in different terms. For example, if a battery-powered smartphone is equipped with a distributed communication modem, the smartphone may use the distributed communication modem only if desired. More specifically, in a vehicle where the terminal wants to know traffic light blinking information as in the service of FIG. 4, when the terminal checks one frame of a broadcast channel, the terminal may find a traffic light blinking service. At this time, the terminal can know the blinking time of the traffic light by analyzing the data area. As another example, the terminal may also discover a speaker access service, but using the terminal may be selected by the terminal.

In this case, as an example, it may be considered that the terminal is a vehicle. For example, in the case of a vehicle, the traffic light blinking notification service may be a very useful and necessary service. In view of this, the system may pre-determine the slot number of the traffic light blinking notification service. That is, a fixed slot number can be allocated to a specific service. In this case, the slot broadcasted to all the terminals without contention in the fixed slot number may be the aforementioned 'designated broadcast slot'. For example, when the traffic light blink notification service is a designated broadcast slot, the terminals (or vehicles) may already know the slot number of the traffic light blink notification service. Accordingly, the terminal (or vehicle) may perform a 'fixed repeat reception' operation on the slot without performing the quick search described above.

As another example, the following describes a method for setting a different frame length for a specific slot. In the following description, for convenience of description, a description is made based on a designated broadcast slot, but the same may be applied to other types of slots. On the other hand, as an example, a frame longer in length than the above-described 1 second frame may be referred to as a “super frame”. However, the above terms are referred to for convenience of description and are not limited to the above names. That is, the same operation may be described in different terms.

For example, the traffic light blinking service may be serviced in the form of a designated broadcast slot in slot 0 of the broadcast channel. In this case, the case where the length of the super frame is 4 seconds may be considered. When operating based on the super frame, the information on the traffic light blinking service can be time-divided by each traffic light every 4 seconds to transmit a signal. If there are four traffic lights at 100m intervals on the road, each traffic light can transmit a signal only once every four seconds. Therefore, when the communication reach distance of the distributed communication is set to about 300m to 1000m, when there are four traffic lights at 100m intervals, the phenomenon that the transmission signals of the traffic lights collide at an intermediate point can be avoided by using the super frame.

Like a traffic light blinking notification service, a broadcast channel is received and the service is received using the received information itself, but the service may not be received using only the received information itself. In this case, the service should be received in the used channel by using the information received from the broadcast channel.

As an example, it may be considered to use a speaker installed in the auditorium. In this case, the terminal may wirelessly access the speaker system using distributed communication to receive a service. As an example, the above-described operation is referred to as a 'speaker connection service' and is not limited to the above-described embodiment.

In more detail, the speaker system may broadcast its connection information in a broadcast channel. That is, the speaker system may notify its existence and broadcast information for using the speaker to neighboring terminals. In this case, the terminal that wants to use the speaker access service may first receive one frame through a broadcast channel. That is, the terminal can receive the broadcast frame, through which the speaker system connection information can be confirmed. That is, the terminal may find a 'speaker connection service' through quick searching. In this case, the speaker system may inform the frequency of the synchronous TDMA use channel necessary for using the device, and inform the user of information for accessing the channel. More specifically, the access information can be provided to the terminal by transmitting the frame by including the number of allocated slots and the accessible slot position to access the frame. For example, the terminal may identify a channel used for speaker connection in a broadcast channel using frequency channel 1. FIG. In this case, it may be considered that the frequency channel 2 is a usable channel that can be accessed, the slots accessible are “all”, and the number of allocated slots required for access is four. However, the above-described case is only one example, and is not limited thereto. The terminal may use the speaker system after allocating four slots in the second frequency channel after acquiring information on the use channel through the broadcast channel. Here, since the speaker system always receives the second frequency channel, the speaker system may receive data transmitted to its own address.

In this case, as an example, it is necessary to set a frame structure used for the use channel. For example, FIG. 6 may be a MAC frame structure for a use channel. In this case, the MAC frame structure may include at least one of a service field, a source address field, a destination address field, a control field, a data field, and a CRC field. For example, the source address field may be an address of a terminal transmitting data, and the destination address field may be an address of a terminal receiving data. That is, address information necessary for data transmission may be included. Meanwhile, as an example, a fixed slot may be used in consideration of power consumption. In this case, the services may be provided through a predetermined fixed slot. Through this, the terminal may not receive all the slots, but receive only the slots required by the terminal to provide a service or receive the service.

At this time, since it is not possible to know when and how the service is provided through the fixed slot, the terminal to receive the corresponding service using the fixed slot should always receive the reserved slots. In addition, a terminal that wants to provide a corresponding service in a pre-reserved fixed slot needs to compete to use the slot. In this case, the terminal may provide a corresponding service by using a slot after winning the competition.

As a specific example, referring to FIG. 7, a case where the system reserves four slots (e.g. 0, 125, 250, 375) in advance for a chat may be considered. At this time, all terminals wishing to be provided with a chat service may always receive these four slots. That is, terminals receiving a service may always receive data in a fixed slot for a specific service. In addition, the terminal to transmit data may perform a competition, and transmit the corresponding chat text to another terminal in the winning slot. That is, when a service provider wants to transmit a text to another terminal for chatting, the terminal may provide a service after acquiring a slot occupancy opportunity through competition with other terminals in a designated slot. For example, since only four slots among 500 slots in one second are received even from the standpoint of receiving a service, power consumption may be reduced, and the present invention is not limited to the above-described embodiment.

In addition, as an example, when a service is provided using both a broadcast channel and a use channel, the broadcast channel and the use channel may provide information while interacting with each other, thereby increasing system efficiency. For example, a response to the slot received in the use channel may be transmitted through the broadcast channel.

In more detail, the configuration of the broadcast channel response to the slot received in the use channel may include at least one of ACK, NACK, time, number, order, amount, and availability. As another example, the broadcast channel response configuration may be set differently based on information received through the use channel, and is not limited to the above-described embodiment. As an example, an ACK / NACK signal may be considered. In this case, a terminal providing a service mainly uses a broadcast channel, and the terminal may simultaneously transmit ACK information of a use channel to a plurality of terminals through a broadcast channel. Through the above, the service providing terminal may not use the slot of the use channel to send an ACK, thereby reducing the amount of resources used in the system.

As a specific example, referring to FIG. 8, the service providing terminal may broadcast service information in broadcast slot 0. In this case, the terminal 1, the terminal 2 and the terminal 3 may transmit data to the service providing terminal in the use channel. However, this is only one example and is not limited to the above-described embodiment. In this case, after one second passes as one frame, the service providing terminal may transmit ACKs for data received from the terminal 1, the terminal 2, and the terminal 3 to the previous frame in the broadcast slot 0 in the next frame. Through this, the terminal 1, the terminal 2 and the terminal 3 may receive the corresponding ACK information, respectively. In this case, as an example, a field for ACK information may be set in a field included in a broadcast slot for the above operation. In this case, a subfield corresponding to each terminal may exist in the field for the ACK information. The terminal providing the service may provide ACK information to each terminal through subfields corresponding to the respective terminals among the fields for the ACK information. That is, as described above, when collecting ACKs and transmitting them through a broadcast channel, resource consumption may be reduced in the system.

As another example, slots may be allocated to groups. For example, one frame may be 1 second. However, unlike the above-described case, the case of 50 slots in the frame may be considered. At this time, the number of slots may be set differently, and is not limited to the above-described embodiment. In the following description, 50 slots are included in one frame for convenience of description.

At this time, for example, the competition for slot allocation may use a competition agency channel. The contention substitute channel may mean a channel that competes in advance in slot s-1 to use slot s of the primary channel. In addition, it is possible to operate based on "slot clearing" by transmitting a contention signal from subslot 0 in the previous slot s-1 of the contention substitute channel to prevent neighboring terminals from attempting to use the corresponding slot s. In addition, subslot 1 may be set as a clearing subslot for an ACK signal in response to the allocation request, which is not limited to the above-described embodiment.

Specifically, referring to FIG. 9B, slots constituting a frame of a synchronous TDMA channel may be divided into a plurality of slot groups. For example, 50 slots may be included in one frame. In this case, as an example, when the slot group is set to five, each slot group may have ten slots. However, this is just one example, and the number of slots included in the slot group may be changed. In this case, as an example, the number of slots included in the slot group may be determined based on the number of slots included in one frame. That is, in order to include the same number of slots in each group, the number of slots included in one frame may be a multiple of the number of slots included in the group. As another example, as shown in FIG. 9C, only specific slots of a frame may be designated as a slot group. That is, not all slots are divided into groups as shown in FIG. 9B, and only specific slots of a plurality of slots may be formed as a group as shown in FIG. 9C. For example, in FIG. 9C, one slot group may be provided.

At this time, for example, if there is no slot group, if the terminal wants to allocate 10 slots, 10 slots should be allocated through competition. However, in the case of FIG. 9 (b) or FIG. 9 (c), even if the slot assignment is successful only once, the corresponding terminal group can be used by the corresponding terminal.

As an example, it may be considered that the terminal intends to allocate 10 slots of 0, 5, 10, 15, 20, 25, 30, 35, 40 and 45 at once. In this case, when the terminal succeeds in allocation in any slot belonging to the slot group, the terminal may be regarded as allocating the corresponding slot group. For example, if the terminal successfully allocates slot 20, it may be regarded as allocating the remaining nine slots.

In the case of a broadcast slot, even if slot 20 is successfully allocated, the remaining 9 slots can be regarded as successful. In contrast, in the case of the use slot, there may be a counterpart terminal for using the use slot, so that the slot assignment may be successful only after receiving an ACK from the counterpart terminal. For example, the terminal may finally allocate the corresponding slot group only when an ACK for the slot assignment is received in the slot 25 after the slot 20.

More specifically, referring to FIG. 10, the terminal may be allocated a slot based on the slot group as described above (S1010). In this case, the terminal may wait for a slot belonging to the corresponding slot group (S1020). Thereafter, the terminal may perform a competition for the corresponding slot and receive the slot through the allocation request (S1030). At this time, if the terminal fails the slot allocation request (S1040), the terminal slots again in the corresponding slot group. Can wait. On the other hand, if the terminal succeeds in the slot allocation request (S1040), the terminal may wait for a slot belonging to the slot group (S1050). As described above, in the case of a broadcast slot, if the terminal succeeds in the slot allocation request Slots can be allocated. On the other hand, in the use slot, the terminal should receive the ACK as described above, it can wait for the ACK. In this case, when the terminal does not receive the allocation ACK (S1060), the terminal may wait for the slot belonging to the slot group again (S1020). On the other hand, when the terminal receives the allocation ACK (S1060), the terminal is the corresponding slot That is, the terminal may use the group (S1070). That is, the terminal may use the slots included in the slot group when receiving an ACK by performing slot allocation on one of the slot groups.

In this case, the terminal should finally perform slot clearing in all slots belonging to the slot group after the allocation of the corresponding slot group is finally determined by the reception of the ACK. That is, the terminal may perform slot clearing by using the sub slot 0 of the competing substitute channel in the slots before all the slots belonging to the corresponding slot group, and based on this, the slot group may be continuously used. This makes it possible to assign slots in real time while quickly allocating slots in real time.

In the following description, a slot allocation method is described in which a terminal transmits a slot map to avoid a hidden node problem. As described above, in the case of allocating slots to two terminals in a synchronous TDMA distributed communication system, when one terminal attempts to allocate slots through contention, the other terminal should send an ACK for the allocation in the corresponding slot of the next frame. Allocation to the slot can be completed. At this time, the ACK can be sent when the corresponding slot is empty from the other terminal's point of view. That is, when two terminals exist in a situation known as a hidden node problem, an ACK for allocation cannot be sent.

Therefore, in order to avoid the hidden node problem, it is necessary for two terminals to allocate slots to know each other's slot map. In this case, the slot map may be a map in which each terminal receives all slots of a synchronous TDMA frame and determines whether the slot is currently in use or not and records them. For example, a method of creating a slot map may actually indicate a slot having a good CRC by receiving a slot of a corresponding channel for one frame. On the other hand, even if the channel is occupied, the CRC may not be in good condition because various kinds of interference and noise exist in the channel. In consideration of the foregoing, a slot map may be created by carrier sensing a slot of a corresponding channel for one frame. Through the above, the terminal can determine whether the slot is occupied even if the CRC is not in a good state. As another example, since there is a competition agency channel competition mapped with the corresponding channel, the channel may be sensed to create a slot map. Since the competitive agency channel always operates through carrier sensing, a reliable slot map can be created by sensing the competition channel and creating a slot map.

In this case, when the above-described slot map is created, a recognition method for the slot map may be required.

More specifically, referring to FIG. 11, each of the terminals may create a slot map for each terminal (S1110). At this time, the terminal requesting slot allocation may transmit its slot map together with the slot allocation request. Subsequently, after the other terminal receives the slot allocation request and the slot map, the counterpart terminal may create a slot map indicating the slot slots commonly available in the received slot map and its slot map (S1130). You can create a slot map to show the slots available to each other. Hereinafter, this is referred to as an "effective slot map," but this is for convenience of description only and is not limited to the name. Thereafter, the other terminal may transmit the slot allocation ACK and the valid slot map together to the terminal that has made the slot allocation request (S1140). Then, the terminal which has made the slot allocation request additionally utilizes the valid slot map received with the ACK. That is, the slot allocation request terminal knows the valid slot map information based on the slot map of the other party, so that the problem with the hidden node can be solved and a plurality of slots are allocated based on the slot allocation request terminal. You can do it.

As another example, referring to FIG. 12, each of the terminals may create a slot map for each terminal (S1210). In this case, when the terminal requesting slot allocation requests slot allocation, the terminal may additionally request a slot map of the other party. . In operation S1220, the other terminal may receive the slot allocation request and the slot map request, and transmit a slot allocation request to the terminal together with the ACK for the slot map and the slot allocation. The UE requesting the UE may additionally allocate a slot by using the counterpart slot map received by receiving the counterpart slot map together with the ACK. That is, an effective slot map may be created from the counterpart slot map received by the terminal requesting slot allocation and its slot map. Through this, the terminal requesting slot allocation may allocate a slot.

As another example, referring to FIG. 13, each of the terminals may create a slot map for each terminal (S1310). Then, the terminal may broadcast its slot map information using the broadcast slot (S1320). At this time, the other terminal may check the slot map information on the terminal requesting slot allocation based on the broadcasted information. In this case, the counterpart terminal may create an effective slot map from the broadcasted slot map and its own slot map (S1330). Then, the counterpart terminal may request slot allocation from the slot map broadcast terminal by using the calculated effective slot map. have. In this case, the broadcast slot map may be a slot map for a channel other than the channel to which the broadcast slot belongs. That is, when there are several synchronous TDMA channels, slot maps of other channels can be broadcast.

For example, as described above, the speaker system may transmit a slot map of the use channel that is received by the speaker system in the general broadcast slot of the broadcast channel. In this case, the distributed terminal to access the speaker system may check the slot map of the use channel in the broadcast channel, and then create an effective slot map for the use channel to access the speaker system. In this manner, a slot map of a channel that provides a service may be broadcasted in a broadcast channel so that a terminal that a terminal accesses to the terminal can easily win a collision race. Through this, other terminals may first receive slot map information of a channel providing a service in a broadcast channel, and then create an effective slot map to request slot allocation in a channel providing a service to the corresponding broadcast terminal.

However, in the above-described case, it is necessary to continuously broadcast the slot map information in the broadcast slot of the broadcast channel. That is, since the number of bits for providing information in the broadcast slot is limited, if a large number of bits are used for slot map information transmission, other information cannot be transmitted as much. Accordingly, the terminal may examine the channel usage rate of the service providing channel and use the scheme of providing a slot map of the service providing channel in the slot of the broadcast channel only when the channel usage rate of the service providing channel is higher than a predetermined usage rate. That is, as described above only under certain conditions, the slot map may be transmitted through the broadcast channel, and the present invention is not limited to the above-described embodiment.

14 is a block diagram of a terminal device.

The terminal device 100 may include a transmitter 110 for transmitting a wireless signal, a receiver 120 for receiving a wireless signal, and a process 130 for controlling the transmitter 110 and the receiver 120. In this case, the terminal 100 may perform communication with an external device through the transmitter 110 and the receiver 120. In this case, the external device may be another terminal device, a base station, or another device capable of performing communication, and is not limited to the above-described embodiment.

In this case, as described above, the terminal selects a slot and performs an operation based on the processor 130. In addition, it is also possible to include another structure, and is not limited to the above-mentioned structure. That is, the above-described configuration may be the minimum configuration for carrying out the present invention, and it may be possible that additional configurations are included.

In addition, the terminal device of the present invention described above is not limited to a smartphone as a mobile terminal. For example, the terminal device may be one of a drone, a vehicle, an IoT device, and other devices. For example, collision avoidance between drones may be performed based on the present invention. Also, for example, collision avoidance between vehicles may be performed based on inter-vehicle communication based on the present invention. In addition, as an example, a collision between a plurality of devices may be avoided as the home appliance, and the present disclosure is not limited to the above-described embodiment.

That is, the above-described invention can be applied when collision avoidance is required as an apparatus capable of performing communication.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, while the preferred embodiments of the present specification have been shown and described, the present specification is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present specification claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present specification.

In the present specification, both the object invention and the method invention are described, and the description of both inventions may be supplementarily applied as necessary.

In addition, the present invention has been described with reference to the preferred embodiments. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

100: terminal
110: transmitter
120: receiver
130: processor

Claims (20)

A method of receiving a service in a synchronous TDMA distributed system,
Receiving service information from a service providing terminal using a broadcast slot;
Discovering the service based on the received service information;
Using the found service; including,
If the found service is a service available as the service information itself of the received broadcast slot, the terminal uses the service through the broadcast slot based on the service information of the received broadcast slot,
If the found service is not a service available by the service information itself of the received broadcast slot, the terminal uses the service through a use slot based on the service information.
The method of claim 1,
When the terminal uses the service through the use slot, the service providing terminal allocates the use slot through slot allocation competition, and uses the allocated use slot use in the allocated use slot of the first frame. Send a consent request signal for
Receive ACK information on the consent request signal received from the terminal in the allocated use slot of the second frame,
And the second frame is the next frame of the first frame.
The method of claim 2,
After receiving the ACK information, the service providing terminal transmits response information to the terminal.
The response information is transmitted to a plurality of terminals through the broadcast slot.
The method of claim 3
The response information includes at least one of ACK, NACK, time, number, order, amount, and availability.
The method of claim 2,
In the case of allocating the use slot, specific use slots are preset as use slot groups among the use slots of the frame, and the service providing terminal selects one of the slots included in the use slot group to compete. The slot is allocated through the allocated slot, the slot group allocation request is transmitted to the terminal through the allocated slot, and the ACK for the slot group allocation request is received from the terminal in the next slot of the allocated slot. And all slots of the used slot group to which they belong are allocated based on slot clearing.
The method of claim 2,
The use slot is allocated based on a slot map,
The slot map is a map indicating whether available slots constituting one frame, the service providing method.
The method of claim 6,
And the slot map includes information about available slots based on carrier sensing performed in a competing surrogate channel mapped to the channel instead of a channel in which used slots exist.
The method of claim 6,
The service providing terminal transmits the slot map information to the terminal together with the agreement request signal for using the allocated use slot,
The terminal creates a valid slot map indicating a valid use slot that can be used simultaneously based on the slot map information, and transmits the valid slot map together with the ACK to the service providing terminal.
The method of claim 6,
The service providing terminal transmits a slot map creation request to the terminal with the agreement request signal for using the allocated use slot,
The terminal creates a slot map, and transmits the created slot map with the ACK to the service providing terminal,
The service providing terminal creates a valid slot map indicating a valid use slot available at the same time based on the received slot map information of the terminal, and allocates the used slots based on the valid slot map.
The method of claim 6,
The service providing terminal receives the slot map information of the terminal that the terminal broadcasts through the broadcast slot,
And a valid slot map indicating a valid use slot available at the same time based on the received slot map information of the terminal, and allocating the used slots based on the valid slot map.
The method of claim 1,
The broadcast slot is included in at least one of a mixed channel and a broadcast channel,
And the usage slot is included in at least one of the mixed channel and the usage channel.
The method of claim 11,
And the broadcast slot includes at least one of a general broadcast slot, a designated broadcast slot, and a fixed broadcast slot.
The method of claim 12,
Predetermined specific services of a channel correspond to the fixed broadcast slots among the broadcast slots,
When the terminal is provided with the specific service, the terminal always receives the fixed broadcast slots,
The terminal providing the specific service is allocated the fixed broadcast slot through competition in the fixed broadcast slot, and provides the specific service using the assigned fixed broadcast slot.
The method of claim 12,
The service related information transmitted in the broadcast slot includes the number of allocated slots required for the service, the minimum number of slots required for the service, the maximum number of slots required for the service, the use channel, the frequency information of the mixed channel, and the current information in the used slot. And at least one or more of the number of slots being occupied and transmitting signals.
The method of claim 11,
And the use slot comprises at least one of a general use slot, a designated use slot, and a fixed use slot.
The method of claim 1,
The broadcast slot is allocated to the service providing terminal and used.
The method of claim 16,
When the broadcast slot is allocated, specific broadcast slots are preset to the broadcast slot group among the broadcast slots of the frame, and the service providing terminal selects any one of the slots belonging to the broadcast slot group and competes through the competition. If allocated, all slots of the broadcast slot group to which the allocated slot belongs are allocated based on slot clearing.
A terminal receiving a service in a synchronous TDMA distributed system,
A transmitter for transmitting a signal;
Receiving unit for receiving a signal;
Includes a processor for controlling the transmitter and the receiver,
The processor,
Receive service information using a broadcast slot from a service providing terminal through the receiving unit,
Discover the service based on the received service information,
Use the services found above,
If the found service is a service available as the received information of the broadcast slot itself, the terminal uses the service through the broadcast slot based on the received broadcast slot information,
If the found service is not a service available by the information of the received broadcast slot itself, the terminal uses the service through the use slot based on the received service information.
A method for providing a service by a terminal in a synchronous TDMA distributed system,
Transmitting service information using a broadcast slot to a terminal receiving the service;
Providing the service to the terminal receiving the service; Includes,
When the service is a service available as the service information itself of the broadcast slot, the terminal provides the service through the broadcast slot based on the service information of the broadcast slot to the terminal receiving the service,
If the service is not a service available as the service information of the broadcast slot, the terminal provides the service through a use slot based on the service information.
A terminal providing a service in a synchronous TDMA distributed system,
A transmitter for transmitting a signal;
Receiving unit for receiving a signal;
Includes a processor for controlling the transmitter and the receiver,
The processor,
Transmitting service information using a broadcast slot to a terminal receiving a service through the transmitter;
Providing the service to the terminal receiving the service,
When the service is a service available as the service information itself of the broadcast slot, the terminal provides the service through the broadcast slot based on the service information of the broadcast slot to the terminal receiving the service,
If the service is not a service available as the service information of the broadcast slot, the terminal provides the service through a use slot based on the service information.

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