Abstract: A circuit board, according to an embodiment, comprises: a first insulating layer; a second insulating layer disposed on one surface of the first insulating layer; and a third insulating layer disposed on the other surface of the first insulating layer. A circuit pattern is disposed on at least one insulating layer from among the first to third insulating layers, at least one insulating layer from among the first to third insulating layers comprises glass fiber, at least one insulating layer from among the first to third insulating layers does not comprise glass fiber, and the thicknesses of the first to third insulating layers are different from each other.

Abstract: A method of checking the integrity of a wireless distributed communication packet using a trust field in a wireless distributed communication system may comprise: allowing a first terminal to acquire a trust-field-generation-specific secret key of a second terminal; allowing the second terminal to generate a trust field utilizing all bits to be transmitted to the first terminal; allowing the second terminal to generate a first packet using the trust field and all the bits to be transmitted; allowing the second terminal to transmit the first packet to the first terminal; and allowing the first terminal to check the integrity of the first packet using the trust-field-generation-specific secret key and the trust field included in the first packet.

Abstract: An operation method of a station in a wireless distributed communication system may comprise: determining a probability distribution for selecting a first value in each subslot of a slot of a channel used for performing contention; selecting the first value based on the probability distribution in a subslot k among predetermined subslots, wherein k is 0 or a positive integer; transmitting a tone signal in the subslot k when the first value is selected in the subslot k; and winning the contention by selecting the first value in remaining subslots after the subslot k.

Abstract: A method of checking the integrity of a wireless distributed communication packet using a trust field in a wireless distributed communication system may comprise: allowing a first terminal to acquire a trust-field-generation-specific secret key of a second terminal; allowing the second terminal to generate a trust field utilizing all bits to be transmitted to the first terminal; allowing the second terminal to generate a first packet using the trust field and all the bits to be transmitted; allowing the second terminal to transmit the first packet to the first terminal; and allowing the first terminal to check the integrity of the first packet using the trust-field-generation-specific secret key and the trust field included in the first packet.

Abstract: An operation method of a first distributed terminal, in a synchronized wireless distributed communication system which has a plurality of communication resources configured with a plurality of channels having different center frequencies and includes the first distributed terminal and a second distributed terminal, may comprise receiving slots mapped to the communication resources in a resource allocation channel having a center frequency independent from the plurality of channels; measuring communication environments of the communication resources by using a mapping relationship between the received slots of the resource allocation channel and the communication resources; selecting a first communication resource to be allocated using the measured communication environments of the communication resources; allocating the selected first communication resource; and continuously occupying the allocated first communication resource.

Abstract: An operation method of a first terminal in a wireless distributed communication system using a synchronous TDMA scheme may comprise configuring a position of a first sub-slot in a frame of an information tone channel; detecting, by the first terminal in a sleep state, a first information tone signal transmitted from a second terminal in the first sub-slot; maintaining a state of the first terminal to the sleep state when the first information tone signal is not detected in the first sub-slot, and transitioning the state of the first terminal to a wake-up state when the first information tone signal is detected in the first sub-slot; and transmitting and receiving, by the first terminal having transitioned to the wake-up state, a data signal to and from the second terminal through a preconfigured data channel.

Abstract: An operation method of a first communication node in a wireless distributed communication system may comprise: providing a group code and a primary secret key to a third communication node via a second communication node; receiving, from the third communication node, a first packet including a first group trust field through wireless distributed communication, the first group trust field being generated using the group code and the primary secret key; and performing a trustworthiness check of the received first packet by using the first group trust field included in the received first packet, the group code, and the primary secret key.

Abstract: A channel resource management method performed by a first communication node in a communication system may comprise: monitoring channel information broadcast packets transmitted from other communication nodes; receiving a first broadcast packet, which is a channel information broadcast packet transmitted from a third communication node that is included in the other communication nodes and performs one-to-one communication with a second communication node included in the other communication nodes; and managing a one-to-one channel resource for one-to-one communication with a fourth communication node included in the other communication nodes based on information included in the first broadcast packet, wherein the first broadcast packet includes information on a first one-to-one channel resource allocated for one-to-one communication between the second and third communication nodes.

Abstract: Disclosed herein are a method for ensuring trustworthiness of a packet in a distributed synchronous wireless communication system and an apparatus using the method. The method, performed by terminals and an apparatus for checking the trustworthiness of a packet, includes: transmitting, by a first terminal, a packet including a trust field to a second terminal using distributed wireless communication; receiving, by a third terminal, the packet from the first terminal; requesting, by the third terminal, checking of trustworthiness by delivering the packet and information about the packet reception time to the apparatus; checking, by the apparatus, the trustworthiness of the packet using the trust field and the information about the packet reception time; generating, by the apparatus, a trust result notification packet when the result of checking the trustworthiness indicates that the packet is untrusted; and transmitting, by the apparatus, the trust result notification packet to the second terminal.

Abstract: The present invention relates to a method of avoiding collision in a. More specifically, the present invention relates to a method of effectively avoiding collision when resources are allocated to and used by substantial mobile terminals in a synchronous wireless distribution communication system. The method of avoiding collision includes: determining, by a terminal, a slot to be transmitted in a main frequency channel; in a slot prior to the determined slot, performing contention using a contention deputy channel having a different frequency from the main frequency channel; and using the selected slot of the main frequency channel when winning the contention.

Abstract: An operation method of a first distributed terminal, in a synchronized wireless distributed communication system which has a plurality of communication resources configured with a plurality of channels having different center frequencies and includes the first distributed terminal and a second distributed terminal, may comprise receiving slots mapped to the communication resources in a resource allocation channel having a center frequency independent from the plurality of channels; measuring communication environments of the communication resources by using a mapping relationship between the received slots of the resource allocation channel and the communication resources; selecting a first communication resource to be allocated using the measured communication environments of the communication resources; allocating the selected first communication resource; and continuously occupying the allocated first communication resource.

Abstract: An operation method of a first terminal in a wireless distributed communication system using a synchronous TDMA scheme may comprise configuring a position of a first sub-slot in a frame of an information tone channel; detecting, by the first terminal in a sleep state, a first information tone signal transmitted from a second terminal in the first sub-slot; maintaining a state of the first terminal to the sleep state when the first information tone signal is not detected in the first sub-slot, and transitioning the state of the first terminal to a wake-up state when the first information tone signal is detected in the first sub-slot; and transmitting and receiving, by the first terminal having transitioned to the wake-up state, a data signal to and from the second terminal through a preconfigured data channel.

Abstract: The present invention relates to a method of avoiding collision in a. More specifically, the present invention relates to a method of effectively avoiding collision when resources are allocated to and used by substantial mobile terminals in a synchronous wireless distribution communication system. The method of avoiding collision includes: determining, by a terminal, a slot to be transmitted in a main frequency channel; in a slot prior to the determined slot, performing contention using a contention deputy channel having a different frequency from the main frequency channel; and using the selected slot of the main frequency channel when winning the contention.

Abstract: Provided are a method and an apparatus for processing a transmission signal, which reduce a peak value to an appropriate magnitude by appropriately distorting a final transmission signal through implementation into simple hardware having a small memory and a small operation amount to effectively reduce a peak-to-average power ratio (PAPR) by effectively processing a signal for wireless communication in real time.

Abstract: Provided is a method of assigning a slot, the method including transmitting an assignment request for at least one slot of a first frame to a terminal, determining whether an acknowledgement (ACK) of the assignment request is received from the terminal, in a slot corresponding to the at least one slot in a second frame which is a subsequent frame of the first frame, and determining whether the at least one slot for which the assignment request is transmitted has been assigned based on whether the ACK of the assignment request is received.

Abstract: Provided are a method and an apparatus for processing a transmission signal, which reduce a peak value to an appropriate magnitude by appropriately distorting a final transmission signal through implementation into simple hardware having a small memory and a small operation amount to effectively reduce a peak-to-average power ratio (PAPR) by effectively processing a signal for wireless communication in real time.

Abstract: Disclosed is an uplink synchronization method of a base station according to the present invention includes receiving an initial access signal from a terminal; obtaining an uplink synchronization using the received initial access signal; informing the terminal about obtainment of the uplink synchronization; and receiving a data signal from the terminal. According to the present invention, a marine wireless communication system may efficiently perform uplink synchronization between the base station and the terminal, and may efficiently operate wireless resources.

Abstract: Provided is an access method using carrier sensing in a communication system. A random access method according to an embodiment of the present invention includes performing sensing with respect to a carrier in a first part of a radio slot, and transmitting preemptive occupation signals for the carrier through the carrier in a second part after the first part of the radio slot when the carrier is in a non-occupied state based on the sensing result in the first part. Accordingly, in the random access method according to the present invention, efficient random access may be made possible even when there are access requests from a large number of terminals in a narrow frequency band in a communication system.

Abstract: Disclosed is an uplink synchronization method of a base station according to the present invention includes receiving an initial access signal from a terminal; obtaining an uplink synchronization using the received initial access signal; informing the terminal about obtainment of the uplink synchronization; and receiving a data signal from the terminal. According to the present invention, a marine wireless communication system may efficiently perform uplink synchronization between the base station and the terminal, and may efficiently operate wireless resources.

Abstract: A data communication apparatus according to the present invention includes a channel determination unit for determining frequency channels to be monitored on the basis of a current location of the ship station, a performance measurement unit for measuring channel performance for each of the determined frequency channels, a channel selection unit for selecting one frequency channel from among the determined frequency channels on the basis of the measured channel performance, and a data communication unit for performing data communication with the coast station using the selected frequency channel.