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 wireless communication system including transmitters for determining a transmission rate for an associated receiver according to channel state information fed back from associated receivers, and transmitting packets at the determined transmission rate. In a communication method, a transmitter groups packets to be transmitted to the receivers according to transmission rates, and generates frames configured by packets with an identical transmission rate. The transmitter aggregates frames with different transmission rates into one transmission burst, and sends the transmission burst. The data communication method based on packet aggregation can efficiently manage resources by determining transmission rates for reception stations (STAs) on the basis of feedback channel state information in a transmission STA, aggregating packets to be transmitted to the reception STAs to form a packet group, and transmitting packet groups with different transmission rates using one multi-rate aggregation (MRA) burst.

Abstract: Disclosed is a receiver for configuring a Block Acknowledgement (BA) frame in a wireless communication system for acknowledgement of a data transmission from a transmitter. The receiver receives a Block Acknowledgement Request (BAR) frame in the data transmission from the transmitter and determines an overall size of a bitmap for the BA frame from the BAR frame to acknowledge the data transmission. The receiver configures the BA frame of the response to include the bitmap having the determined overall size, and transmits the configured BA frame to the transmitter. The bitmap of the BA frame includes bits representing reception results of packets of the data transmission received from the transmitter.

Abstract: A method is provided for efficiently allocating a transmission period in a wireless network system. An access point (AP) transmits a PSMP frame indicating a downlink period provided to each station (STA) and a minimum amount of an uplink period allocated to each STA, and at least one sub PSMP frame indicating an uplink period additionally provided for an STA that transmitted a resource request message for remaining queued data in the uplink period indicated by the PSMP frame. If the uplink period indicated by the PSMP frame is insufficient to transmit the queued data, the STA transmits a data unit including a part of the queued data and a resource request message for the remaining queued data in the uplink period. After transmitting the resource request message, the STA receives the sub PSMP frame after the full period indicated by the sub PSMP frame, and transmits the remaining queued data to the AP in the uplink period indicted by the sub PSMP frame.

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 method for managing a segment threshold includes determining whether a packet has been transmitted to a predetermined terminal, receiving from the predetermined terminal a response message indicating that the predetermined terminal has received the packet without any errors, if a packet has been transmitted to the predetermined terminal, receiving signal intensity data of a current packet transmitted from the predetermined terminal, and adjusting the segment threshold using the received signal intensity data of a current packet, if the response message has been received.

Abstract: A data transceiver and a data reception method for reducing power consumption in a mobile communication system are provided. The data transceiver includes a transmitter which transmits a plurality of data frames during a predetermined transmission period; and a receiver which receives data frames in the predetermined transmission period, if the transmission period is allowed and monitors with minimal operation power whether data transmission is in progress or completed in the transmission period, if the transmission period is not allowed.

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: Disclosed is a method and an apparatus for self-calibrating direct current (DC) offset and imbalance between orthogonal signals, which may occur in a mobile transceiver. In the apparatus, a transmitter of a mobile terminal functions as a signal generator, and a receiver of the mobile terminal functions as a response characteristic detector. Further, a baseband processor applies test signals to the transmitter, receives the test signals returning from the receiver, and compensates the imbalance and DC offset for the transmitter side and the receiver side by using the test signals.

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 channel estimation method in a Multiple Input Multiple Output (MIMO) mobile communication system having a plurality of transmission antennas and a plurality of reception antennas is provided. In a method of transmitting, by a transmitter, channel estimation signals for channel estimation at a receiver, the transmission antennas transmit the same channel estimation signals for a first frame transmission duration, and transmit predetermined channel estimation signals corresponding to the number of the transmission antennas for a second frame transmission duration.

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: An apparatus is provided for efficiently allocating a transmission period in a WLAN system. An access point (AP) transmits a PSMP message providing a downlink period and an uplink period provided to each station (STA), and at least one sub PSMP frame indicating a period of at least one of a downlink and an uplink for an STA requiring additional resource allocation. After exchanging data with the AP in the downlink and uplink periods provided by the PSMP frame, if there is a need for additional resource allocation, the STA receives the at least one sub PSMP frame and exchanges data with the AP in the period provided by the each sub PSMP frame.

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 system 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 method 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 method 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: An apparatus is provided for efficiently allocating a transmission period in a wireless network system. An access point (AP) transmits a PSMP frame indicating a downlink period provided to each station (STA) and a minimum amount of an uplink period allocated to each STA, and at least one sub PSMP frame indicating an uplink period additionally provided for an STA that transmitted a resource request message for remaining queued data in the uplink period indicated by the PSMP frame. If the uplink period indicated by the PSMP frame is insufficient to transmit the queued data, the STA transmits a data unit including a part of the queued data and a resource request message for the remaining queued data in the uplink period. After transmitting the resource request message, the STA receives the sub PSMP frame after the full period indicated by the sub PSMP frame, and transmits the remaining queued data to the AP in the uplink period indicted by the sub PSMP frame.