Mobile Ad Hoc Network Channel Access Protocol And Power Saving Mechanism

As information technology quickly develops, the demand for mobile communications becomes more and more strong, and wireless communications networks have also been rapid development and popularization. But for some special situation, the traditional fixed network and the wireless networks which require pre-deployment network infrastructure have been impossible or difficult to be used effectively. For example, in the battlefield troop advance and expand fast in battlefield, after an earthquake or flood rescue as so on. In such a case would require a temporary and quick self-organizing wireless network technology, namely, Ad Hoc network communication technologies.Ad Hoc network is a wireless, mobile, self-organizing network. It has no central control node, and the mobile nodes can be in communication with each other using multi-hop wireless links. Since the above-mentioned characteristics of Ad Hoc network, a variety of protocols and technologies of the traditional fixed network and cellular mobile communication network can not be directly used. We need to design special protocol and technologies for Ad Hoc network. Channel Access Protocol controls nodes to access wireless channel and packets to be sent and received in the channel. It can perceive channel state fastest and play a decisive role in Ad Hoc network. Therefore, it is one of the key technologies for Ad Hoc network. In Ad Hoc networks mobile nodes generally have battery-powered, and battery energy is limited. So, about how to make use of power saving technologies to extend the life of the nodes is the Ad Hoc network research hot spots.On the basis of Ad Hoc networks multi-hop and omni-directional radio antenna, this dissertation improves receiver oriented access protocol RIMA-DP, making data transmission in the next hop node to be able to predict the packet arrival time form monitored ACK packet. In order to verify the validity of new protocol RIMA-DPACK via NS2 simulation result display in multi-hop transmission, the new protocol has some improvement on the throughput and end-to-end delay than the original protocol RIMA-DP in the end-to-end throughput and latency improvements. Based on the analysis of the MAC layer power saving mechanisms, this dissertation designs MAC layer power saving mechanism 802.11TPS protocol for multi-hop Ad Hoc network. In the 802.11TPS protocol, time-driven to ensure low-load nodes be in a sleep state for most of time. And packet-driven has used to make the irrespective nodes in a sleep state when data packet is in transmission, on the one hand, in order to save energy, on the other hand can also reduce data conflicts. In order to compare 802.11TPS and 802.11PSM performance through ns2 simulation environment for the conduct of experiments, this thesis has compared the power saving effect at low load and high load. In the low-load case, the 802.11PSM is little better. And in the high-load case, the 802.11TPS is much better. In the NS2 simulation environment, this thesis has compared the power saving effect of 802.11TPS with 802.11PSM at low load and high load. In the low-load case, the 802.11PSM is little better. And in the high-load case, the 802.11TPS is much better. About the packet loss rate, from low load to high load of the simulation process, the 802.11TPS is more robustness.