Abstract: Provided are a mobile station that may determine a Precoding Matrix Index (PMI) of a serving channel, generate Channel State Information (CSI) based on only interference channels, and feed back the PMI and the CSI to a serving base station, a base station that may design a precoding vector based on the PMI and the CSI, and an operation of the mobile station. Also, provided are a mobile station that may determine a PMI based on only interference channels, generate CSI of a serving channel, and feed back the PMI and the CSI to a serving base station, a base station that may design a precoding vector based on the PMI and the CSI, and an operation method of the mobile station.

Abstract: A terminal receives a unique sequence from each of at least two base stations, and transmits a mixture of quantized unique sequences to a serving base station. The serving base station extracts components respectively corresponding to base stations from the mixture of the quantized unique sequences, and estimates a location of a terminal based on the extracted components. The serving base station may calculate a received signal strength or a delay for each of the unique sequences received by the terminal, based on the extracted components, and estimate the location of the terminal based on the received signal strength or the delay. In addition, the terminal may estimate its own location by performing an algorithm used by the serving base station.

Abstract: A communication system performing a coordinated multipoint transmission is provided. A mobile station may measure expected channel quality information when an interference of a serving base station does not exist. The serving base station may determine whether a neighbor base station and the serving base station are eligible to perform the coordinated multipoint transmission. The serving base station may determine whether the neighbor base station and the serving base station are eligible to perform the coordinated multipoint transmission using a criterion associated with an evaluation of an increase in a transmission rate of the mobile station.

Abstract: Described herein is a method of sharing a frequency resource between a plurality of transmission/reception pairs in a communication system. Also described is an inner-cell coordinator included in the communication system that may be used to carry out the method of sharing a frequency resource between a plurality of transmission/reception pairs.

Abstract: A plurality of transmit-receive pairs may operate in any one mode between an orthogonal mode and a concurrent mode. The transmit-receive pairs may collect interference channel information in a different time interval when operating in an orthogonal mode. In a concurrent mode, the transmit-receive pairs may apply a simultaneous transmission/reception scheme based on the collected interference channel information.

Abstract: Described herein is a resource allocation method for a hierarchical cellular system, and a transmission frame for performing the method. A macrocell dedicated resource and a shared resource are respectively controlled based on a usage rate of the macrocell dedicated resource and a usage rate of the shared resource. The macrocell reports a usage plan of the shared resource that the macrocell uses to a small cell, and the small cell may allocate the shared resource to terminals based on the usage plan of the shared resource. A control message related to the usage plan may be transmitted/received via the transmission frame.

Abstract: A cryptographic method using dual encryption keys and a wireless local area network (LAN) system therefor includes (a) generating a first group key in N wireless terminals forming an ad-hoc group, where N is equal to or greater than two, (b) generating a second group key in a main wireless terminal to perform a key distribution center function among the N wireless terminals, and transmitting the second group key to (N?1) sub wireless terminal, and (c) encoding data using the second group key, and transmitting the encoded data between the N wireless terminals. Data security in a wireless LAN system of an ad-hoc network is increased by creating a first group key having a low frequency of use using a group password, and using a random key generation algorithm to create, distribute, and modify a second group key in a wireless terminal functioning as a key distribution center.

Abstract: An apparatus and method for exchanging frequency bands used by a plurality of base stations are provided. A base station for exchanging frequency bands includes a receiving unit to receive first quiet time duration information of an adjacent base station, a frequency band measuring unit to determine first frequency band measuring information with respect to a first frequency band used by the adjacent base station based on the first quiet time duration information, a frequency band exchange-determining unit to determine whether to exchange frequency bands with each other based on the first frequency band measuring information, and a transmitting unit to transmit data to a terminal using the first frequency band according to the determined result.

Abstract: A method and system for controlling the transmission power of a terminal transmitting frames in a wireless communication system, the frames having a frame structure including a header field containing information related to a transmission rate and length of data transmitted in a frame and a data field having the data. The transmitting terminal transmits the header field to a receiving terminal at a maximum transmit power level available to the transmitting terminal so that second terminals other than the transmitting terminal and the receiving terminal within the wireless communication system can identify that resources are in use. The transmitting terminal transmits the data field at an optimum transmit power level great enough to allow the data field to reach the receiving terminal.

Abstract: Communication apparatuses and a transmission frame having a downlink subframe are provided. The downlink subframe of the transmission frame may include a downlink coordination zone where a plurality of femto base stations may perform the downlink communication with at least one terminal among a plurality of terminals using a different radio resource, and a downlink shared zone where the plurality of femto base stations may perform the downlink communication with particular terminals among the plurality of terminals using a shared radio resource. The transmission frame may further include an uplink subframe that includes an uplink coordination zone and an uplink shared zone.

Abstract: Provided is a communication method and a data frame for a communication system having a relay station. An uplink sub-frame of the data frame may include a first uplink relay sub-frame which corresponds to a time frame where relay stations selected among a plurality of relay stations simultaneously transmit uplink relay signals to a base station, and a second uplink relay sub-frame which corresponds to a time frame where the remaining relay stations transmit remaining uplink relay signals to the base station using a scheduled radio resource. A downlink sub-frame of the data frame may include a first downlink relay sub-frame which corresponds to a time frame where a base station simultaneously transmits downlink relay signals to relay stations selected from among a plurality of relay stations, and a second downlink relay sub-frame which corresponds to a time frame where the base station transmits remaining downlink relay signals to the remaining relay stations using a scheduled radio resource.

Abstract: Provided are a signal transmission method and a network apparatus to control interference in a radio communication network. A terminal may transmit to the network apparatus, signal quality information associated with a radio channel formed between the terminal and a corresponding base station. The corresponding base station may output a signal received by the plurality of terminals, based on the signal quality information.

Abstract: Disclosed is a method for detecting a hidden station in a specific station constituting a wireless communication network that includes receiving a frame after a lapse of an idle state interval longer than a predetermined waiting time; determining that there is a hidden station, if a size of the received frame is equal to a size of an Acknowledge (ACK) frame; and determining that there is no hidden station, if the size of the received frame is not equal to the size of the ACK frame.

Abstract: A communication device, base station, terminal, and method for a multi-cell network include a scheduler configured to generate outer cell scheduling information by scheduling outer cell frequency resources for outer terminals in outer cells of a plurality of cells, and a scheduling information provider configured to provide the outer cell scheduling information to the plurality of cells.

Abstract: A scheduling method includes classifying, by a PC, terminals into delay-sensitive terminals and delay-insensitive terminals according to their traffic types; setting an initial value and a maximum value of a poll failure counter of each of the delay-sensitive terminals; polling each of the delay-sensitive terminals; determining whether there exists a delay-sensitive terminal of which a current value of the poll failure counter is less than the maximum value; and if there exists no delay-sensitive terminal of which the present value of the poll failure counter is less than the maximum value, sequentially polling the delay-sensitive terminals and the delay-insensitive terminals.

Abstract: A multi-band scheduling method determines frequency bands for each of a plurality of frames existing in a single session queue from among a plurality of frequency bands based on data characteristics of each of the plurality of frames. In particular, the multi-band scheduling method may assign a frame with a high significance to a frequency band having a superior channel state, thereby increasing communication reliability. Also, a broadcasting service system may use the multi-band scheduling method to effectively provide the broadcasting services.

Abstract: An encryption key distribution method capable of performing fast roaming by differentially distributing encryption keys in advance, according to access authorization classes, in a wireless access network and a roaming method using distributed encryption keys are provided. The encryption key distribution method comprises: receiving a command to communicate with an access point not available for communication using an encryption key currently selected in the encryption key set; determining access authorization of the access point not available for communications; selecting an encryption key from the encryption key set obtained in advance corresponding to the determined access authorization; and using the selected encryption key to encrypt a transmission message and communicate with the access point not available for communication.

Abstract: A method of guaranteeing users' anonymity and a wireless LAN system therefor are provided. In a wireless LAN system, the method of guaranteeing user' anonymity includes (a) creating a plurality of temporary address sets, each of which corresponds to a unique Media Access Control (MAC) address of a wireless terminal and transmitting the temporary address set to the corresponding wireless terminal, and (b) performing data packet transmission between the wireless terminal and the wireless access node using a temporary address selected from the temporary address set as a source address or a destination address. Therefore, it is possible to guarantee users' anonymity and improve security of a system by not exposing a MAC address during data packet transmission between a wireless terminal and a wireless access node.

Abstract: An apparatus is provided for allocating a transmission period in a wireless network system. An access point (AP) transmits a PSMP frame indicating a downlink period and an uplink period allocated to each station (STA), and at least one sub PSMP frame indicating an allocated downlink period for at least one of a retransmission of downlink data and a transmission of an ACK indicating successful receipt of uplink data. After exchanging data with the AP in the downlink and uplink periods indicated by the PSMP frame, an STA receives the each sub PSMP frame, and performs at least one of a reception of the retransmitted downlink data and a reception of the ACK in the downlink period indicated by the each sub MAP frame.

Abstract: A femtocell base station apparatus may sense a wireless propagation environment around the femtocell base station apparatus to obtain wireless propagation environment information, transmit first control information including the wireless propagation environment information to at least one master base station adjacent to the femtocell base station apparatus, receive second control information from the at least one master base station, and control data communication performed between the femtocell base station apparatus and a mobile terminal based on the second control information.