전력제어기법을 사용한 이중채널 Ad hoc MAC 프로토콜

Abstract

Ad hoc network is a wireless network with out infrastructure. It is very useful in military and other application such as disaster and rescue area, home networking and wireless communication between vehicles in telematics service. Ad hoc MAC (medium access control) protocols with directional antennas have been proposed to improve throughput of Ad hoc Networks. But, directional transmissions have the problem of deafness and the problem of determination of neighbor's location. The ToneDMAC protocol with an omnidirectional out-of-band tone has been proposed to solve the problem of deafness. Also, the dual-channel (DUCHA) protocol has been proposed to solve the exposed terminal problem using the NCTS mechanism and the separated channels which prevent packet collisions. In the dual-channel directional MAC (DUDMAC), omnidirectional transmission on the control channel overcomes deafness and solves the problem of determination of neighbor's location. Directional transmission on the data channel and the new blocking algorithm for directional antennas improve spatial reuse. The dual-channel directional MAC with an out-of-band tone (ToneDUDMAC) uses DDATA_Tone and OCTS_Tone to reduce blocking area and to improve spatial reuse. In this thesis, the power controlled dual-channel directional MAC (PCDUDMAC) and the power controlled dual-channel directional MAC with an out-of-band Tone (PCToneDUDMAC) are proposed. In the proposed MAC protocol, the power control mechanism reduces energy consumption of nodes. And the blocking area in DUDMAC and ToneDUDMAC divides into the FULL_BLOCKING area and the SEMI_BLOCKING area to improve spatial reuse. The blocking table is used to decide whether a node is in its blocking area or not. Nodes in the SEMI_BLOCKING area can transmit data and therefore improve spatial reuse. Te throughput of the proposed MAC protocols is confirmed by computer simulations using the QualNet simulator ver 3.8. In simulations, we use the single-hop random topology of 180 nodes and the 5-hop random topology of 60 nodes. The simulation results show that the proposed MAC protocols improve throughput of nodes and reduce energy consumption of nodes. Relative to the ToneDMAC protocol, the DUDMAC protocol improves throughput by 62% and 77% in the 5-hop topology and the single-hop topology, respectively. Relative to the DUDMAC protocol, the ToneDUDMAC protocol improves throughput by 25% and 32% in the 5-hop topology and the single-hop topology, respectively. The PCDUDMAC protocol improves throughput by 38% and reduces energy consumption by 19% relative to the DUDMAC protocol in the single-hop topology. The PCToneDUDMAC protocol improves throughput 16% and reduces energy consumption by 18% relative to the ToneDUDMAC protocol in the single-hop topology. Therefore, the power controlled MAC protocols proposed in this thesis improve throughput and reduce energy consumption of nodes. Because of the proposed MAC protocol have benefits above explained. It can be useful for mobile communication in Ad hoc networks and inter vehicle communication in telematics service.