Abstract: In a medium access method for contention and non-contention, a poll number for stations, or wireless terminals for communication, is managed by a base station so as to guarantee smooth traffic and improved Quality of Service (QoS). A first group of stations is provided for the non-contention, and a second group of stations is provided for the contention. The method includes (a) preparing a contention-free access message attempting access of the first group, (b) detecting a transmission time of a contention access message attempting access of the second group, (c) embedding the contention-free access message in the contention access message so as to transmit the embedded message to at least one of the first and second groups, and (d) receiving the contention access message, in which the contention-free access message is embedded, at the at least one of the first and second groups, and endowing any one of the first and second groups with a priority to attempt access to a medium in turn.

Abstract: In a method and system for providing selective media data in a multimedia conference service, a selective media data provision request of a participant who wants to be selectively provided with media data is transmitted to a media server using Session Initiation Protocol (SIP), and media data selected or converted according to the request to the user are provided, thereby improving user convenience.

Abstract: A method of re-transmitting a packet of an access point (AP) in a polling-based Wireless Local Area Network (WLAN) includes: scheduling a super frame to form a first period of providing a polling message to arbitrary stations at the AP and allowing only stations receiving the polling message to get access to a medium without contention, and to form a second period of allowing the stations to get access to the medium through contention; transmitting packets stored in a first transmission queue to the corresponding stations during the first period of the super frame; and enqueuing a packet whose transmission results in failure during a first portion of a second transmission queue to re-transmit the packet whose transmission has resulted in failure during the second period upon a determination that at least one of the packets transmitted to the stations has resulted in a failure to be transmitted.

Abstract: In a medium access method for contention and non-contention, a poll number for stations, or wireless terminals for communication, is managed by a base station so as to guarantee smooth traffic and improved Quality of Service (QoS). A first group of stations is provided for the non-contention, and a second group of stations is provided for the contention. The method includes (a) preparing a contention-free access message attempting access of the first group, (b) detecting a transmission time of a contention access message attempting access of the second group, (c) embedding the contention-free access message in the contention access message so as to transmit the embedded message to at least one of the first and second groups, and (d) receiving the contention access message, in which the contention-free access message is embedded, at the at least one of the first and second groups, and endowing any one of the first and second groups with a priority to attempt access to a medium in turn.

Abstract: A method for processing packets in a polling-based WLAN system comprises: scheduling a superframe to include a first period in which only a terminal receiving a polling message from an access point (AP) is allowed to access a medium without contention, the AP transmitting the polling message to arbitrary terminals, and a second period in which a terminal is allowed to access the medium with contention; firstly transmitting, by means of the AP, during a first sub-period in the first period of the superframe, packets stored in a queue of the AP to the arbitrary terminals; and secondly transmitting, during a second sub-period of the first period, packets that are not transmitted in time during the first sub-period in the first period but are accumulated in the queue.