Abstract: An inter-symbol interference cancellation method for an orthogonal frequency division multiple access system is provided. The inter-symbol interference cancellation method includes transmitting, at a base station, an OFDMA symbol having a first half part and a second half part divided in time; receiving, at a mobile station, the OFDMA symbol; and restoring the OFDMA symbol by repeating one of the first half part or the second half part. The ISI cancellation method for an OFDMA communication system of the present invention uses an OFDMA symbol having two identical parts sequentially arranged in time, whereby it is possible to recover a transmitted OFDMA symbol if at least one of the two parts is successfully received.

Abstract: An uplink signal receiving method and apparatus using successive interference cancellation (SIC) in a wireless transmission system based on Orthogonal Frequency Division Multiple Access (OFDMA) are provided.

Abstract: A method and apparatus save power in a multimode wireless terminal having plural communication modems for supporting different communication systems. The multimode wireless terminal performs its basic functions of reception and transmission, while only one of the communication modems is turned on and the others are turned off so as to reduce power consumption. This results in extension of the utilization time of the multimode wireless terminal.

Abstract: A packet processing terminal and method for compressing a header of a packet. When it is determined an IP header is to be compressed in order that a terminal removes overhead of a generated packet, an IP header compression option is added to a socket option of a socket generated in order to exchange the packet between an application module and an OS module. And, when the application module sets the IP header compression option, the IP header of the packet is compressed by the OS module using a compression method corresponding to option information of the set IP header compression option.

Abstract: An Orthogonal Frequency Division Multiple Access (OFDMA)-based mobile terminal and a method for measuring reception channel quality for use in the OFDMA-based mobile terminal are provided. A mobile terminal includes a transceiver for exchanging frequency signal with a base station and a control unit for calculating a Carrier-to-Interference and Noise Ratio (CINR) of a data subcarrier with a second preamble of a downlink frame received through the transceiver. A mobile terminal and a method for measuring a channel quality for the mobile terminal enable calculating a CINR of data subcarriers using information contained in a second preamble that is provided in a downlink frame proposed, whereby the mobile terminal can provide a base station with more reliable channel quality information, resulting in avoiding degradation of communication quality and improvement of system throughput.

Abstract: An inter-symbol interference cancellation method for an orthogonal frequency division multiple access system is provided. The inter-symbol interference cancellation method includes transmitting, at a base station, an OFDMA symbol having a first half part and a second half part divided in time; receiving, at a mobile station, the OFDMA symbol; and restoring the OFDMA symbol by repeating one of the first half part or the second half part. The ISI cancellation method for an OFDMA communication system of the present invention uses an OFDMA symbol having two identical parts sequentially arranged in time, whereby it is possible to recover a transmitted OFDMA symbol if at least one of the two parts is successfully received.

Abstract: An uplink signal receiving method and apparatus using successive interference cancellation (SIC) in a wireless transmission system based on Orthogonal Frequency Division Multiple Access (OFDMA) are provided.

Abstract: An apparatus and method for reducing inter-subcarrier interference (ICI) in an Orthogonal Frequency Division Multiple Access (OFDMA) system are provided. The method includes determining a correction frequency from uplink intermediate frequency (IF) signals subjected to analog-to-digital conversion when an uplink radio frequency (RF) signal is input through an antenna of a base station and each uplink IF signal (I(n)+j1(n)) is input,; and correcting the uplink IF signal so as to correspond to the determined correction frequency. Thereby, it is possible to reduce the ICI of each terminal caused by mismatching of the interval of the inter-subcarrier center frequency of each terminal that constitutes the uplink signal in the OFDMA system.

Abstract: Disclosed is an apparatus and method for compensating for frequency offset in a wireless communication system using an OFDM system which can compensate for phase change due to carrier frequency offset and sampling frequency offset of data carried on subcarriers.

Abstract: A method and apparatus save power in a multimode wireless terminal having plural communication modems for supporting different communication systems. The multimode wireless terminal performs its basic functions of reception and transmission, while only one of the communication modems is turned on and the others are turned off so as to reduce power consumption. This results in extension of the utilization time of the multimode wireless terminal.

Abstract: A system for preventing tampering with recorded accumulated running distance data is provided which comprises a first memory, a tampering prevention control unit, and a third memory. The tampering prevention control unit is configured to output an error message if the vehicle serial number data stored in the second memory unit is not equal to the vehicle serial number data stored in the first memory unit and in the third memory unit. The tampering prevention control unit is configured to determine whether the accumulated running distance data stored in the second memory unit is equal to the accumulated running distance data stored in the first memory unit, and if not, the tampering prevention control unit stores the accumulated running distance data stored in the second memory unit to the first memory unit.

Abstract: A packet processing terminal and method for compressing a header of a packet. When it is determined an IP header is to be compressed in order that a terminal removes overhead of a generated packet, an IP header compression option is added to a socket option of a socket generated in order to exchange the packet between an application module and an OS module. And, when the application module sets the IP header compression option, the IP header of the packet is compressed by the OS module using a compression method corresponding to option information of the set IP header compression option.

Abstract: A medium access control method and apparatus and program storage device in a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) based wireless LAN (Local Area Network) classifies stations in a CSMA/CA based wireless LAN system into a number of groups according to a transmission priority to assign a different DIFS (Distributed Coordination Function InterFrame Space) to each group.

Abstract: A medium access control method of a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) based wireless LAN (Local Area Network) provides contention-free medium access authority to a station or access point receiving a request signal by: transmitting a request signal frame from an arbitrary station to another arbitrary station or to an access point via a medium occupied in transmission contention with a CSMA/CA algorithm using a DCF (Distributed Coordination Function) interframe space; and transmitting an acknowledgment signal frame from the station or the access point receiving the request signal frame to the station transmitting the request signal frame via an occupied medium using a short interframe space.

Abstract: A wireless terminal can be used in place of a remote control for controlling appliances located at a remote place. Unlike using infrared remote controls to control a plurality of appliances, one 802.11x wireless terminal can now control the appliances. Therefore, a user having a mobile phone, a smart phone, a PDA, a VoIP terminal or any other wireless terminal can easily control a plurality of appliances. In particular, a terminal such as a PDA with a special image display device can be provided with a user interface that has the exactly same configuration as a remote control. On the other hand, a general mobile phone with a display only has a special character indicating a remote control function.

Abstract: A method and apparatus for controlling gain of an optical fiber amplifier includes a plurality of optical isolators, an excitation light source, a wavelength division optical fiber coupler, and a special optical fiber. At least one of the optical isolators is disposed at both input and output ports of the optical fiber amplifier so that an input signal light can propagate in one direction. The wavelength division optical fiber coupler couples excitation light from the excitation light source to the input signal light or separates one of the excitation light and the input signal light from the other.