Study of High-Throughput MAC Protocol for Wireless Ad Hoc Networks

[[abstract]]載波感測多重存取與碰撞避免（CSMA/CA）是IEEE 802.11中的媒體存取控制（media access control, MAC）技術。在CSMA/CA中，採用傳輸控制封包（RTS/CTS）和資料封包（DATA/ACK）的程序來避免碰撞。然而，因為同時傳輸並不被允許，所以傳統CSMA/CA的輸出（throughput）是被限制的。 在本篇論文中，我們研究同時傳輸媒體存取控制（concurrent transmission MAC, CTMAC）技術，它允許在無線隨意網路下同時傳輸來增加throughput。在CTMAC中，在傳輸控制封包和資料封包之間插入一個額外的控制間隔（additional control gap, ACG），在ACG期間內，其他節點交換RTS/CTS訊框使多重同時傳輸可以被實現。我們在無線隨意網路的實驗下模擬CTMAC和傳統CSMA/CA，根據模擬的結果，我們可以看出CTMAC在throughput效能表現上遠勝過傳統的CSMA/CA。[[abstract]]Carrier sense multiple access with collision avoidance (CSMA/CA) is the media access control (MAC) scheme for IEEE 802.11. In CSMA/CA, the procedure with the transmissions of control packets (RTS/CTS) and data packets (DATA/ACK) is employed to avoid the collisions. However, since concurrent transmissions are not allowed, the throughput of traditional CSMA/CA is limited. In this thesis, we study the CTMAC (concurrent transmission MAC) scheme, which allows concurrent transmissions to increase the throughput, for wireless ad hoc networks. In CTMAC, an additional control gap (ACG) is inserted between the transmissions of control packets (RTS/CTS) and data packets (DATA/ACK), and during the period of ACG, other nodes exchange the frames of RTS/CTS so that multiple concurrent transmissions can be realized. We simulate CTMAC and traditional CSMA/CA in the experimental wireless ad hoc networks. According to the simulation results, we found that CTMAC outperforms traditional CSMA/CA in the throughput.[[note]]碩