| US 7,616,612 B2 | ||
| Media access control apparatus and method for guaranteeing quality of service in wireless LAN | ||
| Ki Jong Koo, Daejeon (Korea, Republic of); and Dae Hwan Hwang, Daejeon (Korea, Republic of) | ||
| Assigned to Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of) | ||
| Filed on Jan. 07, 2009, as Appl. No. 12/349,867. | ||
| Application 12/349867 is a continuation of application No. 10/917684, filed on Aug. 12, 2004, granted, now 7,489,666. | ||
| Claims priority of application No. 10-2003-0097155 (KR), filed on Dec. 26, 2003. | ||
| Prior Publication US 2009/0122804 A1, May 14, 2009 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. H04J 3/00 (2006.01) | ||
| U.S. Cl. 370—336 [332/465] | 11 Claims |
| 1. A media access control (MAC) apparatus comprising:
a first transmit queue storing a voice frame;
a second transmit queue storing a non-voice frame;
a frame handler extracting a user priority, from a frame received from an upper layer, mapping the frame to an access category
(AC), and storing the frame in the first transmit queue or the second transmit queue;
a MAC controller determining a backoff operation timing and a frame transmission timing by checking a media status;
a first arbitration inter-frame space (AIFS) timer and a second AIFS timer, each reducing a predetermined timer value set
by the MAC controller by a predetermined value unit;
a first backoff block and a second backoff block, each independently performing backoff operations for each AC using a predetermined
backoff count value wherein the backoff count value corresponds to a contention window (CW) wherein the value of the contention
window (CW) incrementally increases by CWnew=2(CWold+1)−1 whenever transmission fails;
a contention resolution unit, which transmits the voice frame having a higher priority first and gives up transmission of
the non-voice frame when two ACs simultaneously end the backoff operations;
a frame detector, which determines whether or not to transmit an ACK frame by checking an ACK policy bit from a header of
the received frame when a frame is received from a physical layer; and
a receive queue storing the received frame and transmitting the received frame to the upper layer.
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