Abstract: A transmitter configured to support a multimode and a multiband, using radio frequency (RF) digital-to-analog converters (DACs), includes a first RF DAC configured to transmit a first signal in a first frequency band, and a second RF DAC configured to transmit a second signal in a second frequency band different from the first frequency band. The transmitter further includes an impedance controller configured to adjust impedance of one of the first RF DAC and the second RF DAC operating in an impedance matching mode to adjust a frequency range of another one of the first RF DAC and the second RF DAC operating in a data transmission mode.

Abstract: A method of determining whether to switch off a base station's own power in the base station within a cellular network may comprise: receiving terminal messages having real number values from terminals within cell coverage of the base station; calculating real number values of base-station messages individually regarding the terminals based on the received terminal messages; transmitting the base-station messages having the calculated real number values individually to the terminals; repeatedly performing the receiving, the calculating, and the transmitting until the calculated real number values of the base-station messages are converged to constant values; when the real number values of the base-station messages are converged, calculating a base-station message convergence value, which is one real number value regarding the terminals, based on the converged real number values of the terminal messages; and/or determining whether to switch off the base station's own power based on the base-station message con

Abstract: A method and apparatus for performing tunneling signaling over an IP tunneling path connected to an end-to-end path on an IP network are provided, in which an end-to-end signaling flow is received from a sender or a receiver on the end-to-end path, a tunnel signaling flow is generated corresponding to the received end-to-end signaling flow, and the generated tunnel signaling flow is transmitted through the IP tunneling path, the end-to-end signaling flow is forwarded between an entry node and an exit node of the IP tunneling path, and the forwarded end-to-end signaling flow is transmitted to at least any one node on the end-to-end path, wherein the forwarding is simultaneously performed with the transmitting of the tunnel signaling flow, and the transmitting of the end-to-end signaling flow is suspended until the transmitting of the tunnel signaling flow is completed.

Abstract: A central control apparatus and method thereof include a traffic demand receiving unit, a traffic demand calculating unit, a base station efficiency calculating unit, and a base station management unit. The traffic demand receiving unit is configured to receive a required traffic demand and a current location of each of terminals. The traffic demand calculating unit is configured to calculate traffic of each of base stations to which a terminal is unassigned. The base station efficiency calculating unit is configured to calculate an energy efficiency of each of the base stations. The base station management unit configured to verify a base station with an optimum energy efficiency, to activate the base station with the optimum energy efficiency, and to assign the terminals of a corresponding region to the base station with the optimum energy efficiency.

Abstract: An antenna and a communication system with the antenna are provided. The antenna may include a first layer including a plurality of folded stubs, a second layer including a pattern of the folded stubs, and a third layer connected to ground is disposed between the first layer and the second layer.

Abstract: A routing method in a multi-hop cellular system, the method including: maintaining a signal strength in each node included in the multi-hop cellular system; receiving, in at least one neighbor node, a route-request message broadcasted by a source node; dropping or re-broadcasting, by the at least one neighbor node, the route-request message based on a hop count and the signal strength; and storing, in a base station, the route-request message which is received via the at least one neighbor node, based on an elapsed time, or transmitting a route-reply message to the source node via an optimal path which is selected via the stored route-request message.

Abstract: A method and apparatus for performing tunneling signaling over an IP tunneling path connected to an end-to-end path on an IP network are provided, in which an end-to-end signaling flow is received from a sender or a receiver on the end-to-end path, a tunnel signaling flow is generated corresponding to the received end-to-end signaling flow, and the generated tunnel signaling flow is transmitted through the IP tunneling path, the end-to-end signaling flow is forwarded between an entry node and an exit node of the IP tunneling path, and the forwarded end-to-end signaling flow is transmitted to at least any one node on the end-to-end path, wherein the forwarding is simultaneously performed with the transmitting of the tunnel signaling flow, and the transmitting of the end-to-end signaling flow is suspended until the transmitting of the tunnel signaling flow is completed.

Abstract: A method of transmitting/receiving a frame between a portable terminal and a base station in a wireless broadband Internet network are provided. More particularly, a method of transmitting/receiving frames can include activating a session between the portable terminal and the base station, removing at least one header information field included in an Internet protocol (IP) datagram after activating the session, adding a network header which sets a predetermined transport connection identifier (TCID) to the IP datagram, generating the frame, and transmitting the generated frame via the activated session. Preferably, the frame is generated in any one of the portable terminal and the base station, and transmitted to the other one of the portable terminal and the base station.

Abstract: A method of determining a number of antennas, includes calculating a power used by a transmitting device. The method further includes calculating a channel capacity of the transmitting device. The method further includes determining a number of antennas of the transmitting device to be used based on the power and the channel capacity.

Abstract: A method and apparatus for user scheduling in a multi-user multiple input multiple output (MIMO) communication system are provided. The method includes identifying a user group comprising user terminals. The method further includes comparing power consumptions based on the user group. The method further includes scheduling the user terminals based on the comparing.

Abstract: A method of providing a handover service to a mobile communication terminal supporting multi-modal communications, and a mobile communication terminal for performing the method are provided. More particularly, a method of eliminating an interruption of a data transmission service occurring during a handover between different communication networks, and a terminal for performing the method are provided. A method of providing a handover service of a mobile communication terminal supporting multi-modal communications can include: transmitting and receiving data to/from a corresponding node via a first access network and a second access network while simultaneously maintaining an association with the first access network and the second access network, determining a point in time of completing a handover registration, and releasing an association with the first access network after the point in time of completing the handover registration.

Abstract: A system and method for providing Multicast/Broadcast Service (MBS) service to a mobile terminal in an MBS service provisioning system in a Wide Area Network (WAN) network are provided. An authentication server sends a message for requesting resource reservation, in which a Quality-of-Service (QoS) policy is included, when a registration procedure of the mobile terminal is performed. A base station stores the message sent from the authentication server, forwards the message to the mobile terminal, and sets up a channel to the mobile terminal upon receiving from the mobile terminal a request for channel setup based on the QoS policy.

Abstract: A method for determining a transmission power in a multi-input multi-output (MIMO) system based on a cooperative transmission is provided. The method includes setting a power constraint condition of a transmitter and target quality information of a receiver. The method further includes determining the transmission power to be allocated to the transmitter to transmit the data to the receiver based on the power constraint condition and the target quality information.

Abstract: An apparatus and method for providing a seamless communication service in a wireless communication system. The method includes transmitting a first message to a base station when an IP subnet has been changed due to movement of the portable terminal, the first message including a Medium Access Control (MAC) address of the portable terminal, receiving IP address information from the base station, which can be used in a new IP subnet, and configuring a new IP address based on the received IP address information.

Abstract: Disclosed are a system and a method that generates image data that represent a speaker to be distinguished, and enables a mobile terminal to provide a video conference service using the image data that distinguishes the speaker. A video conference apparatus may include a speaker distinguishing unit to distinguish, as a speaker, a participant who is speaking from a plurality of participants in the video conference and an image data generating unit to generate image data that represents the distinguished participant differently from other participants.

Abstract: Provided is a method and device for increasing energy efficiency by adaptively performing clipping with respect to an input signal. The method may adaptively determine a clipping ratio (CR) based on a modulation method of the communication device and perform clipping based on the determined CR.

Abstract: A system for saving energy through control of a sleep mode, and a method of operating the system are provided. The energy-saving system may enable a proxy device to maintain a minimum basic setup necessary for a communication when a host device enters a sleep mode, and may omit an operation performed based on the basic setup when the host device switches to a communication mode, thereby enabling a smooth switch between the sleep mode and the communication mode.

Abstract: An apparatus and method for performing tunnel signaling over an IP tunneling path are provided. The method includes transmitting an end-to-end signaling flow through an end-to-end path connected to the IP tunneling path, generating a tunnel signaling flow corresponding to the end-to-end signaling flow, and transmitting the generated tunnel signaling flow through the IP tunneling path, wherein the end-to-end signaling flow and the tunnel signaling flow respectively include a binding data object storing binding information for an end-to-end session associated with the end-to-end signaling flow or a tunnel session associated with the tunnel signaling flow.

Abstract: A method, medium, and system for reserving resources in a mobile network. A mobile node reports a start of a handover to a present access router if the handover of the mobile node occurs, and the previous access router transmits specified session information to a candidate access router that has a possibility handling the mobile node's handover. A candidate crossover router, which performs a resource reservation work on a new path and a resource release on the previous path, is searched, and a localized resource reservation is established by exchanging a specified resource reservation message before the handover is completed if the candidate crossover router is determined. Accordingly, duplication of resources can be prevented, and a prompt resource reservation can be achieved during the handover.

Abstract: A method of providing a handover service to a mobile communication terminal supporting multi-modal communications, and a mobile communication terminal for performing the method are provided. More particularly, a method of eliminating an interruption of a data transmission service occurring during a handover between different communication networks, and a terminal for performing the method are provided. A method of providing a handover service of a mobile communication terminal supporting multi-modal communications can include: transmitting and receiving data to/from a corresponding node via a first access network and a second access network while simultaneously maintaining an association with the first access network and the second access network, determining a point in time of completing a handover registration, and releasing an association with the first access network after the point in time of completing the handover registration.