Date of Award
Master of Science (MS)
An ad hoc network is a wireless network that does not depend on a pre-configured infrastructure but instead creates network connectivity by utilizing the available nodes to relay packets. In this thesis, we focus on the media access control layer that has a cross-layer design and exploits features of the physical layer. The radios all utilize direct-sequence spread-spectrum (DSSS) modulation and a multiple-input multiple-output (MIMO) antenna system. The channel-access protocol uses transmission scheduling to ensure collision free and fair access to the channel for all nodes. However, a limitation of transmission scheduling is poor utilization of high-quality links. We investigate two methods to achieve higher data rates on those links that have very high signal-to-noise ratios. The first approach builds upon prior work in adapting the spreading factor of DSSS modulation to allow multiple packets to be bundled into a single transmission using an approach called slot-packing. The other approach exploits MIMO for well-conditioned links that allows multiple packets to be multiplexed with a single transmission by using multiple pairs of transmit and receive antennas. Finally, we develop a new protocol that permits both slot-packing and MIMO to be utilized for very high-quality links. We use simulations to investigate the performance of each approach, and show that substantial gains in network performance are achieved when both can be employed. Integration of our new protocol also requires careful design of the routing metrics and queueing strategies.
Kang, Yifan, "Design of a Channel-Access Protocol for a Wireless Ad Hoc Network with MIMO and Adaptive Transmission" (2021). All Theses. 3507.