Abstract: Provided is an association control method for maximizing a message in message (MIM) function in a WLAN environment. According to an exemplary embodiment of the present invention, when all SINR values of transmission links to two or more first clients associated with the first access point are equal to or more than a predetermined capture threshold, SINR value of a transmission link to a second client associated with the second access point is less than the capture threshold, and at least one of the first clients, referred to as a third client group, can be associated with the second access point, associations are modified so that the third client group is associated with the second access point to enable concurrent transmission.

Abstract: Provided is an opportunistic concurrent transmission method for achieving efficient transmission with limited wireless resources in a WLAN environment. According to an exemplary embodiment of the present invention, when a packet to be transmitted is provided in an access point in a wireless network system, information on a link which is performing transmission from another access point is acquired by overhearing transmission from another access point, a signal to interference plus noise ratio (SINR) value of the link is verified by referring an interference map, and the packet is concurrently transmitted when the verified SINR value is equal to or more than a predetermined capture threshold.

Abstract: Provided are a method and system for detecting a bot in a Massive Multiplayer Online Role Playing Game (MMORPG) online and in real time. By analyzing a communication pattern between a client and a server, the bot is detected based on parameters such as data length, inter-arrival time and data length auto correlation. Tests using respective parameters are combined to construct a global decision scheme, and thus more accurate detection results can be obtained. An integrated anti-bot defense system can be built by combining other tests such as a Turing test.

Abstract: An apparatus and method for implementing a vertical handoff between a WLAN and a broadband wireless communication network are provided. The vertical handoff apparatus includes a base station (BS) of the broadband wireless network and at least one access point (AP) of the WLAN within the cell coverage area of the BS, and a switch for forwarding packets between the BS and the at least one AP and processing a handoff between the BS and the at least one AP.

Abstract: The present invention relates to a network management system for analyzing Internet application traffic. An apparatus for Internet application traffic classification benchmark according to the present invention configures two or more Internet application traffic classifications in plug-in scheme to perform a benchmarking function for the performance of each Internet application traffic classification. The apparatus can provide an objective and accurate evaluation for each classification technology by aggregating various Internet application traffic classification technologies by the plug-in scheme.

Abstract: A lossless handover method in vehicular wireless networks is disclosed which is capable of reducing a handover delay and reducing overhead caused by duplicate address detection (DAD) for a new Care-of-Address (CoA) by dividing a handover process into handover at road-sections and handover at intersections. In the handover method, a vehicle continues to use an original CoA configured at an original access router at road-sections even though an AR is changed, thereby reducing a handover delay. A new CoA is configured only at intersections to reduce a binding update time of a home agent which is remotely present in an external network at road-sections. When performing the DAD for a new CoA at intersections, since the vehicle performs the DAD as a background process while performing communication using an original CoA, overhead caused by the DAD can be reduced.

Abstract: The present invention relates to a WLAN virtualization system which is capable of efficiently separating a Basic Service Set (BSS) into a plurality of virtual BSSs in a Time Division Multiplexing (TDM) manner. The WLAN virtualization system includes an Access Point (AP) for providing a plurality of vBSSs, and a plurality of stations corresponding to the vBSSs provided by the AP. Each of the vBSSs is operated on a superframe basis, the superframe being scheduled by a beacon frame transmitted from the AP. The superframe includes the beacon frame, one contention-free period, and one contention period. The CPs of the vBSSs include intervals which do not overlap each other. The vBSSs can be classified into any groups designated by a service provider based on certain criteria such as physical layer, QoS, security level, or network access authority, and times can be allocated to superframes at different rates or frequencies.

Abstract: Provided is a technology for providing an efficient embedding method in virtualizing a wireless test-bed network. In a virtual network embedding method in a wireless test-bed network, at least one packing point is generated in a two-dimensional strip comprised of time and frequency bandwidth, and the best virtual network slice according to the packing point is disposed. To dispose the virtual network slice, a set of packing points on the strip is collected, the suitability of the network slice according to each packing point is determined, and the network slice is disposed such that a left bottom point of the network slice is disposed at a suitable packing point. Accordingly, the length of a TDM super frame in the virtual test-bed network can be minimized.

Abstract: A WLAN distributed/opportunistic scheduling (WDOS) method for acquiring a multi-user diversity gain is disclosed. The WDOS method allows a transmitter (i.e., a transmission user) to observe channel conditions of receivers (i.e., reception users), and commands the transmitter to transmit packets to a specific receiver having a relative good channel condition. The WDOS method uses a modified RTS/CTS exchange method to perform the channel probing. If the transmitter broadcasts the BRTS frame, each receiver transmits a CTS frame after the lapse of its backoff period. According to the reception signal strength distribution, the backoff delay time minimizes the number of CTS collisions irrespective of the number of receivers, reduces an amount of channel probing overheads, and maximizes a multi-user diversity gain. The better the relative channel condition, the lower the backoff delay time.

Abstract: An apparatus and method for determining a vertical handoff for a node supporting a WLAN and an IEEE 802.16 communication system are provided. Reception of a handoff request message from the node is monitored, an expected change in the total throughput of the WLAN in the case where the node is connected to the WLAN is calculated and compared with zero, and if the throughput change is equal to or greater than zero, the handoff request of the node is acknowledged and the node is handed off to the WLAN.

Abstract: Multi-hop wireless networks have benefits in coverage extension and throughput improvement. In this multi-hop wireless networks, multiple channels are available to improve system performance through concurrent transmission. In this invention, a multi-channel assignment method is described.

Abstract: We propose overhear-based transmitting control system in WLANs to improve performance of 802.11 wireless LANs. The main idea of this scheme is that when the transmission of a node fails, one of neighboring nodes with better channel quality retransmits the lost frame in substitution. To do so, every node should maintain overhear table to buffer the transmitted packets that is not yet acknowledged. We also present algorithms to retransmit lost packets, to maintain the overhear table and to compensate for the retransmission of packets of other nodes. The performance of this scheme is evaluated via simulations in terms of MPDU size and average path loss. It shows that in environments where the packet is likely to be lost more, the throughput gain of our proposed scheme performs better.

Abstract: We propose overhear-based transmitting control system in WLANs to improve performance of 802.11 wireless LANs. The main idea of this scheme is that when the transmission of a node fails, one of neighboring nodes with better channel quality retransmits the lost frame in substitution. To do so, every node should maintain overhear table to buffer the transmitted packets that is not yet acknowledged. We also present algorithms to retransmit lost packets, to maintain the overhear table and to compensate for the retransmission of packets of other nodes. The performance of this scheme is evaluated via simulations in terms of MPDU size and average path loss. It shows that in environments where the packet is likely to be lost more, the throughput gain of our proposed scheme performs better.

Abstract: Multi-hop wireless networks have benefits in coverage extension and throughput improvement. In this multi-hop wireless networks, multiple channels are available to improve system performance through concurrent transmission. In this invention, a multi-channel assignment method is described.

Abstract: A WLAN distributed/opportunistic scheduling (WDOS) method for acquiring a multi-user diversity gain is disclosed. The WDOS method allows a transmitter (i.e., a transmission user) to observe channel conditions of receivers (i.e., reception users), and commands the transmitter to transmit packets to a specific receiver having a relative good channel condition. The WDOS method uses a modified RTS/CTS exchange method to perform the channel probing. If the transmitter broadcasts the BRTS frame, each receiver transmits a CTS frame after the lapse of its backoff period. According to the reception signal strength distribution, the backoff delay time minimizes the number of CTS collisions irrespective of the number of receivers, reduces an amount of channel probing overheads, and maximizes a multi-user diversity gain. The better the relative channel condition, the lower the backoff delay time.

Abstract: An apparatus and method for processing a vertical handoff between a WLAN and a broadband wireless communication network are provided. In a method of processing a vertical handoff in a handoff processor having a mapping table in which QoS information for the broadband wireless communication network is mapped to QoS information for the WLAN, QoS information about an STA received from a source network is converted to QoS information suitable for a target network, referring to the mapping table. A message containing the converted QoS information is generated and sent to the target network.

Abstract: An apparatus and method for implementing a vertical handoff between a WLAN and a broadband wireless communication network are provided. The vertical handoff apparatus includes a base station (BS) of the broadband wireless network and at least one access point (AP) of the WLAN within the cell coverage area of the BS, and a switch for forwarding packets between the BS and the at least one AP and processing a handoff between the BS and the at least one AP.

Abstract: An apparatus and method for determining a vertical handoff for a node supporting a WLAN and an IEEE 802.16 communication system are provided. Reception of a handoff request message from the node is monitored, an expected change in the total throughput of the WLAN in the case where the node is connected to the WLAN is calculated and compared with zero, and if the throughput change is equal to or greater than zero, the handoff request of the node is acknowledged and the node is handed off to the WLAN.