Samsung Electronics Co., Ltd.

Byung-in Mun

Song-Yean Cho

Jin-Hyun Sin

Sang-su Nam

Woon-Jae Chung

Hyuck Yoo

Keun-jae Lee

Jin-hee Choi

See-hwan Yoo

Min-Soo Kim

Kil-su Eo

Hyeong-seok Kim

Hye-young Jung

Se-hong Kim

Hye-eun Choi

Jeong-hwan Seo

Rajesh Patharkar

A method and apparatus for measuring the quality of wireless channels based on a result obtained by measuring contentions between stations in a wireless network employing a carrier sense multiple access/collision avoidance (CSMA/CA) medium access control (MAC) method specified in the IEEE 802.11 standard are provided. The method includes determining contentions between stations to transmit frames via a wireless channel that uses a contention-based medium access method, and measuring the quality of the wireless channel based on the determined contentions.

Method and apparatus for measuring quality of wireless channels

An apparatus, system, and method for discovering a path MTU in a data communication network, wherein a path MTU option header is included in a signal message or first data packet and thus a MTU suitable for a routing path can be determined. A network apparatus for discovering a path MTU maximum transmission unit (MTU) in a data communication network, including a MTU-comparing unit MTU-comparer detecting a path MTU recorded on a predetermined packet transferred over a routing path between a source node and a destination node and comparing the detected path MTU with an internal MTU stored in the MTU-comparing unit MTU-comparer; and an event-processing unit event-processor updating the path MTU recorded on the predetermined packet to contain the internal MTU if the detected path MTU is larger than the internal MTU.

Network apparatus, system and method for discovering path MTU in data communication network

A system for reliably broadcasting a data packet under an ad-hoc network environment including a determining unit for determining whether or not at least one node receiving the broadcast data packet is a relay node, a comparing unit for comparing a first relay node sequence number contained in a management packet which the node transmits with a second relay node sequence number stored in a neighbor table of the node, and a control unit for determining whether or not the data packet is retransmitted to the node according to a result of the comparison of the comparing unit. By comparing the second relay node sequence number stored in the neighbor table of the node which has broadcast the data packet with the first relay node sequence numbers transmitted through a Hello packet, it is possible to check whether or not the data packet is lost during broadcasting, and thus it is possible to reduce a loss factor of the data packet which is generated during broadcasting. Thereby, the data packet can be reliably broadcast.

System and method of reliably broadcasting data packet under ad-hoc network environment

A method of controlling a transmission rate and a communication device using the same are disclosed. A method of controlling a transmission rate includes changing a path for packet transmission/reception from a first path to a second path, setting a congestion window and a slow-start threshold to be used in the second path to a congestion window and a slow-start threshold used in the first path, and adapting the congestion window and the slow-start threshold to be used in the second path according to a packet loss generated in the second path.

Method of controlling transmission rate and communication device using the same

A network apparatus for a stable handoff in an IP-based mobile ad hoc network system and a handoff method using the same. Present invention enables a handoff to be stably performed by pre-configuring a handoff to a new access router. The network apparatus of the present invention comprises a movement-determining unit for determining movement depending on the signal strength upon reception of a packet among network apparatuses operating on a communication mobile ad hoc network, and deciding a handoff to a new access router; a router-configuring unit for configuring information on the new access router for the handoff by performing beforehand the handoff to the new access router according to the results of the determination in the movement-determining unit; and a handoff-processing unit for performing the handoff to the new access router using the pre-configured information according to the determination in the movement-determining unit.

Network apparatus for stable handoff in IP-based mobile ad hoc network system, and handoff method using the same

The present invention relates to a method for automatically configuring network addresses of mobile nodes participating in a mobile multi-hop network. The method of the present invention includes a first step of, if a first mobile node belonging to a first network moves into and participates in a second network, detecting that the first mobile node has moved; a second step of securing a route from the first mobile node to a gateway of the second network and requesting network configuration information; and a third step of receiving an available network address allocated by the gateway and changing the network configuration information of the first mobile node.

Method for automatically configuring network addresses in mobile multi-hop network

Disclosed herein is a method and apparatus for encrypting and compressing multimedia data, which transforms and compresses multimedia data through an encryption key in a process of compressing the multimedia data to record and transmit the data, and encrypts the multimedia data to allow the data to be decoded using only the encryption key. The method includes creating Discrete Cosine Transform (DCT) coefficients by applying input multimedia data to a DCT unit, and quantizing the DCT coefficients; encrypting and compressing transformed Differential Coefficients (DC coefficient) and transformed Amplitude Coefficients (AC coefficient) by transforming encoded DC and AC coefficients depending on a certain encryption key at the time of entropy encoding quantized DC and AC coefficients of the quantized DCT coefficients; and Huffmann coding the encrypted DC and AC coefficients and outputting the coded DC and AC coefficients. The method is a data compression method suitable for processing multimedia data for wireless communication.

Method and apparatus for encrypting and compressing multimedia data

A method and system for dynamically updating information registered in ARP cache tables of other terminals in a case where a protocol address of a terminal existing in an ad hoc network changes. The method includes detecting whether protocol addresses of terminals are duplicated and changing the protocol addresses of some of the terminals having the duplicate protocol addresses; by a terminal whose protocol address has changed, transmitting information on the previously used protocol address and its own hardware address to neighboring terminals; updating the address information tables in accordance with the received information; by a terminal whose protocol address has not changed among the terminals having the duplicate protocol addresses, transmitting its own address information to the neighboring terminals; and by the neighboring terminals that has received the address information in the fourth step, updating the address information tables in accordance with the received information.

Method and system for dynamically updating ARP cache tables in an ad hoc network

A method of efficiently transmitting/receiving data using a transport layer in a mobile ad hoc network, and a network device using the method. The method includes a first step of setting, by a sending host, a flag for requesting an ACK-response into a predetermined packet of packets contained in a window for data transmission; a second step of sending, by the sending host, the packet with the flag set thereinto and other packets without any flags contained in the window to a receiving host; and a third step of, by the receiving host, receiving the packets transmitted in the second step, and sending the ACK-response to the packet with the flag set thereinto among the received packets.

Method of efficiently transmitting/receiving data using transport layer in a mobile ad hoc network, and network device using the method

A method and network apparatus for setting a routing path and managing a neighbor node in mobile ad hoc, network environment are provided. The method for setting a routing path in mobile ad hoc network environment includes receiving a packet periodically broadcast from a neighbor node, measuring the quality of a link with the neighbor node through the received packet, calculating routing paths using the routing information of the neighbor node when the measured link quality is higher than a first threshold value, and selecting the shortest routing path to a destination node, among the calculated routing paths, as a path for packet transmission.

Method for managing neighbor nodes and setting a routing path in a mobile ad-hoc network environment and network apparatus using the same

A method for adjusting a transmission rate in the transmission control protocol (TCP) under a mobile ad hoc network environment, including calculating a difference value (Diff) between the current transmission rate (cur_bw) and the previous transmission rate (base_bw), setting up upper and lower thresholds by calculating the standard variation (basebw_var) of the previous transmission rate, and updating the previous transmission rate to the current transmission rate depending upon a comparison result of Diff and the size of the upper and lower thresholds.

Method for adjusting a transmission rate to obtain the optimum transmission rate in a mobile ad hoc network environment

A method and an apparatus for requesting packet redelivery in a mobile ad hoc network environment. The method includes receiving a first packet periodically broadcasted, extracting packet delivery information of a second packet from the first packet, the second packet including data generated by an application program, determining loss of the second packet based on the packet delivery information, and broadcasting a request packet to request redelivery of the second packet, when it is determined that the second packet is lost.

Apparatus and method for retransmitting data packets in mobile ad hoc network environment

A multiprocessor graphics system having a pixel link architecture, includes: 1) a plurality of sub-graphics systems each of which assigned to each of a plurality of sub-screens provided by sectioning a display screen; and 2) a ring network for connecting the plurality of sub-graphics systems. Each of the sub-graphics systems includes a geometry engine, a raster engine, a local frame buffer and a pixel distributor. An interconnection network bottleneck between the raster engine and frame buffer is removed and a conventional memory system can be used by reducing the number of data transmissions between the raster engine and frame buffer while maintaining image parallelism and object parallelism.

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Suwon-si, South Korea

Byung-in Mun