Pham Ngoc Thai

Hierarchical Routing in Wireless Mesh Network

On this paper, we propose a hierarchical routing framework which is adapted to a wireless mesh network (WMN) environment and ensures the most critical issue in the wireless network: load-balancing. We simplify clusters formation and maintenance procedure, propose limited topology broadcasting mechanism allowing WMC to choose the best path to a WMC in adjacent cluster, and connect to a number nearby WMR. Basing on that routing framework we propose a liquid-simulated algorithm to keep load-balances between WMRs.

An Opportunistic Cross-Layer Architecture for New Generation Networks

Cognitive radio in network core devices such as basestations is being considered as a spectrum management solution for future societys communication demands. Aside from new resource allocation algorithms, efficient inter- and intra-protocol processing should be considered. We propose an opportunistic cross layer architecture called COmmon Layer Architecture (COLA) for information exchange between arbitrary layers for New Generation Networks (NWGN) with network-oriented cognitive radio. Through COLA, information from different protocols, as well as different layers, can be efficiently processed with minimized performance degradation. Emulation and simulation results showed improved aggregate throughput, handoff delay, connectivity and packet drop ratio.

An opportunistic power and modulation control algorithm for new generation networks

Since the numbers of wireless communication devices will increase significantly in the future, effective frequency utilization technologies are required for efficient and scalable communication while preventing interference. Cognitive radio is expected to be one of such technologies. In particular, network-oriented cognitive radio architecture is key to the adaptability of the network core. In this paper, we propose an opportunistic power and modulation control algorithm for the new generation network in a network-oriented cognitive radio architecture. We formulate a multi-objective mixed integer optimization problem which maximize aggregate throughput and connectivity while minimizing power consumption. Based on the simulation results, the proposed algorithm achieves better performance in terms of aggregate throughput, connectivity and reduced power consumption.