Abstract: A system and method for performing a handover of a mobile station (MS) by considering Quality of Service (QoS) in a broadband mobile communication system. The method can include the steps of: receiving information about one or more neighbor base stations and reception strengths for the neighbor base stations from a Serving Radio Access System (RAS) currently communicating with the MS; extracting a value of a specific field from the received information about the neighbor base stations; combining the extracted value of the specific field with the reception strengths to thereby obtain combined values, and selecting a maximum value among the combined values; and transmitting a handover (handoff) request message to a base station corresponding to the selected maximum value. The system includes an MS that analyzes information about neighbor stations received in a Mobile Neighbor Base-station Advertisement (MOB_NBR_ADV) message to select a target RAS.

Abstract: Provided are a method and apparatus for enhancing coding efficiency by performing encoding and decoding by optimally calculating quantization intervals and reconstruction values through a distribution of DCT coefficients of each frame, when DCT coefficients of each SNR enhancement layer are quantized in scalable video coding. The encoding apparatus includes: an R-D optimization unit performing Rate-Distortion (R-D) optimization based on a distribution of Discrete Cosine Transform (DCT) coefficients each slice and calculating a first reference value and a second reference value respectively indicating a start point and an end point of DCT coefficients quantized to “0”; a quantization interval setting unit setting adaptive quantization intervals on the basis of a minimum value and a maximum value of the DCT coefficients, the first reference value, and the second reference value; and a mapping unit mapping the DCT coefficients to the adaptive quantization intervals.

Abstract: A handoff method is provided in a communication network including a plurality of fixed nodes attached to a router connected to at least one external network, and at least one mobile node associated with a current fixed node. The method detects movement of a mobile node; prepares a handoff of the mobile node from a current fixed node to potential fixed nodes upon detecting movement of the mobile node; decides whether to handoff to one of the potential fixed nodes as a target fixed node; and performs the handoff from the current fixed node to the target fixed node. The handoff method enables the mobile station to quickly move its association from one access point to another by minimizing a probe delay which is a primary contributor to handoff delay.

Abstract: A method, apparatus and system for providing a video service of a video service system including multimedia video in real time to a mobile terminal connected by a wireless network. A video frame coded by a coding scheme is transmitted to the mobile terminal for decoding and display. The coding scheme may include a first coding scheme and a second coding scheme used together at a predetermined ratio according to the mobile terminal demanding the video service. A server typically receives coding scheme change determining information from the mobile terminal in order to determining whether or not to change the coding scheme for the video frame during transmission of the video frame. The changed coding scheme can be used to transmit the video frame to the mobile terminal according to the result of analyzing the coding scheme change determining information.

Abstract: A sensor network system and method for establishing a data transmission path are is disclosed. The method for establishing a data transmission path of a sink node and the network system which includes a plurality of nodes including the sink node, includes a) requesting nodes on a previously established data transmission path to give their adjacent node information, b) receiving the adjacent node information, c) retrieving adjacent nodes as the sink node moves, and d) reestablishing the data transmission path through the result of retrieval and the adjacent node information. Since the data transmission path isreestablished without flooding, it is possible to reduce energy of the nodes. Also, the method for establishing a data transmission path can be applied to any routing protocols without additional conditions.

Abstract: A handoff method is provided in a communication network including a plurality of fixed nodes attached to a router connected to at least one external network, and at least one mobile node associated with a current fixed node. The method detects movement of a mobile node; prepares a handoff of the mobile node from a current fixed node to potential fixed nodes upon detecting movement of the mobile node; decides whether to handoff to one of the potential fixed nodes as a target fixed node; and performs the handoff from the current fixed node to the target fixed node. The handoff method enables the mobile station to quickly move its association from one access point to another by minimizing a probe delay which is a primary contributor to handoff delay.

Abstract: Disclosed is a method for managing mobility of mobile nodes between heterogeneous networks in an IP-based mobile communication system including a plurality of access nodes for providing an IP service to mobile nodes located in their service areas and a neighbor graph server for supporting connection to the access nodes by the mobile nodes. The method includes classifying the access nodes according to available service level; classifying the mobile nodes according to required service level, generating service level neighbor graphs each including access nodes supporting the same service level; generating a mapping table for mapping the mobile nodes to the neighbor graphs according to service level required by the mobile node; and supporting movement of a mobile node between networks using the neighbor graph and the mapping table.

Abstract: A format converter which performs frame rate conversion and de-interlacing using a bi-directional motion vector and a method thereof are provided. The method includes the steps of (a) estimating a bi-directional motion vector between the current frame and the previous frame from a frame to be interpolated; setting the motion vector of a neighboring block that has the minimum error distortion, among motion vectors estimated in step (a), as the motion vector of the current block; and (c) forming a frame to be interpolated with the motion vector set in step (b).

Abstract: An image stabilizing apparatus for correcting motion of an image recording apparatus by using a bit-plane matching technique, and an image stabilizing method thereof. In the image stabilizing apparatus, a field memory stores input digital image information. A motion detecting circuit calculates an amount of movement of input image information between two screens by using bit-plane matching technique and outputs a motion vector of the image recording apparatus. A motion correcting circuit corrects the motion of the image recording apparatus by moving image information stored in the field memory in an opposite direction to the direction of the motion vector.

Abstract: A format converter which performs frame rate conversion and de-interlacing using a bi-directional motion vector and a method thereof are provided. The method includes the steps of (a) estimating a bi-directional motion vector between the current frame and the previous frame from a frame to be interpolated; setting the motion vector of a neighboring block that has the minimum error distortion, among motion vectors estimated in step (a), as the motion vector of the current block; and (c) forming a frame to be interpolated with the motion vector set in step (b).

Abstract: An apparatus and method for detecting a motion vector by converting an input image into gradient pattern information and comparing gradient pattern information in a motion detection area of a current field with representative pattern information of a previous field. A gradient pattern converter converts a gray level of each pixel in a motion detection area in an input image into a gradient bit pattern by comparing differences between the gray level of the pixel and gray levels of its adjacent pixels with an arbitrary threshold value. A motion vector detector forms a search area sequentially in the motion detection area, compares a gradient bit pattern of the search area with a representative bit pattern of a previous image to calculate and accumulate correlation values, and determines a difference of coordinates of a search area which results in a maximum correlation value and coordinates of the representative bit pattern as a motion vector.