Abstract: A clock and data recovery device includes an equalizer that compensates for channel loss of input data, a phase detector that compares data output from the equalizer and a fed back clock and outputs an up signal and a down signal, a charge pump that operates according to the up signal and the down signal to output a control signal, a loop filter that removes a high-frequency component included in the control signal output from the charge pump, a voltage-controlled oscillator that changes a frequency of the clock and outputs the clock according to the control signal from which the high-frequency component is removed, and a voltage-controlled oscillator buffer that adjusts a slew rate of the clock output by the voltage-controlled oscillator according to the up signal and the down signal directly received from the phase detector and transmits the clock to the phase detector.

Abstract: A clock and data recovery device includes an equalizer that compensates for channel loss of input data, a phase detector that compares a data output from the equalizer with a clock fed back and outputs an up signal and a down signal, a charge pump that operates according to the up signal and the down signal and outputs a control signal, a loop filter that removes high-frequency components included in the control signal, a voltage controlled oscillator that changes a frequency of the clock and outputs a clock with changed frequency, and a data phase adjuster that synchronizes the clock output from the voltage controlled oscillator and the data output from the equalizer by adjusting a phase of the data output from the equalizer by receiving the up signal and the down signal output from the phase detector.

Abstract: The present invention relates to a method and apparatus for providing mobile content to seamlessly transmit content to a mobile node even during a hand-over of the mobile node through local caching devices distributed in a mobile network. When a specific local caching device detects a hand-over of the mobile node, content data transmitted from the specific local caching device is delivered to the mobile node through a mobile CDN controller, or blocking of content from a origin server is revoked to deliver content data from the origin server to the handed-over mobile node.

Abstract: The present disclosure relates to a local caching device, system and method for providing a content caching service. The local caching device receives, from a content provider, at least one part of content requested by a user terminal and then, based on the received part of the requested content, determines whether the requested content is stored in a storage unit. If the requested content is stored, the local caching device registers flow information of the requested content in the storage unit. When content having the same flow information as the registered flow information is requested, the local caching device determines based on content address information whether the requested content is stored.

Abstract: For a user terminal connected to one of cache devices distributed in a network and receiving contents, terminal access information including terminal address information about the user terminal and identification information of the cache device is stored and managed. If a content retransmission request message of the user terminal is detected at other cache device, this is regarded as a handover of the user terminal. This allows a simple detection of handover that occurs during content transmission.

Abstract: The present disclosure relates to a local caching device, system and a method for providing a content caching service. The local caching device checks whether content having address information corresponding to content address information included in a content request message is stored in a storage unit. When the content corresponding to content address information is not stored in the storage unit, the local caching device receives content transmitted from a content providing device in response to the content request message and then checks whether content corresponding to at least part of the received content is stored in the storage unit.

Abstract: Disclosed are a cache synchronization system, a cache synchronization method and a local cache to perform synchronization. The local cache is configured to determine whether to perform synchronization for specific content on the basis of synchronization policy information, if it is determined that synchronization is to be performed, to set a dispersion parameter that defines a synchronization range for the specific content according to the synchronization policy information, and to transmit synchronization information about the specific content, which includes the dispersion parameter, to at least one neighboring local cache.

Abstract: The present disclosure relates to a local caching device, system and a method for providing a content caching service. The local caching device checks whether content having address information corresponding to content address information included in a content request message is stored in a storage unit. When the content corresponding to content address information is not stored in the storage unit, the local caching device receives content transmitted from a content providing device in response to the content request message and then checks whether content corresponding to at least part of the received content is stored in the storage unit.

Abstract: The present disclosure relates to a local caching device, system and method for providing a content caching service. The local caching device receives, from a content provider, at least one part of content requested by a user terminal and then, based on the received part of the requested content, determines whether the requested content is stored in a storage unit. If the requested content is stored, the local caching device registers flow information of the requested content in the storage unit. When content having the same flow information as the registered flow information is requested, the local caching device determines based on content address information whether the requested content is stored.

Abstract: The present invention relates to a method and apparatus for providing mobile content to seamlessly transmit content to a mobile node even during a hand-over of the mobile node through local caching devices distributed in a mobile network. When a specific local caching device detects a hand-over of the mobile node, content data transmitted from the specific local caching device is delivered to the mobile node through a mobile CDN controller, or blocking of content from a origin server is revoked to deliver content data from the origin server to the handed-over mobile node.

Abstract: For a user terminal connected to one of cache devices distributed in a network and receiving contents, terminal access information including terminal address information about the user terminal and identification information of the cache device is stored and managed. If a content retransmission request message of the user terminal is detected at other cache device, this is regarded as a handover of the user terminal. This allows a simple detection of handover that occurs during content transmission.

Abstract: Disclosed are a cache synchronization system, a cache synchronization method and a local cache to perform synchronization. The local cache is configured to determine whether to perform synchronization for specific content on the basis of synchronization policy information, if it is determined that synchronization is to be performed, to set a dispersion parameter that defines a synchronization range for the specific content according to the synchronization policy information, and to transmit synchronization information about the specific content, which includes the dispersion parameter, to at least one neighboring local cache.