Chun-Hao Yang

Bio: Chun-Hao Yang is an academic researcher from National Cheng Kung University. The author has contributed to research in topics: Routing protocol & Network packet. The author has an hindex of 4, co-authored 8 publications receiving 65 citations. Previous affiliations of Chun-Hao Yang include University of Delaware.

An energy-efficient routing protocol in underwater sensor networks

Abstract: Wireless sensor networks can improve the efficiency for collecting information in underwater environments. In the past, researchers collected data under the sea by the way of both sending oceanographic equipments into water and recovering it at the end of mission. The whole process often took long time so real-time services cannot be supported. Wireless sensor networks can detect events and transmit the collected data to a data center immediately. However, current terrestrial routing protocols are not suitable in the underwater sensor networks. Due to unique characteristics in the water, the transmission performance and energy of the routing protocols are inefficient. This paper develops an energy-efficient routing protocol in underwater sensor networks. The protocol is designed to reduce the number of packets transferring in the network, and also decreases the needed energy consumption. The protocol has been evaluated using Network Simulator 2 (NS-2). The results show that the number of reduced packets is considerable.

A cluster-based link recovery mechanism for spectrum aware on-demand routing in cognitive radio ad hoc networks

Abstract: In cognitive radio ad hoc networks (CRAHNs), link failures among secondary users (SUs) primarily result from sudden appearance of primary users (PUs). In tradition, route recovery generates much packet loss before the routes are recovered completely. Recent researches on route recovery process in CRAHNs mainly adopt on-demand route maintenance protocols in wireless networks. This paper proposes a cluster-based link recovery mechanism (CLR) in CRAHNs. CLR recovers failed links locally and does not change the original routes. Since the routes have not been changed, the data packets are able to be cached in the buffer. Data packets can be sent after the links are recovered and hence decreases the amount of packet loss. If there is an intersection area of all PUs’ radio coverage in the network with some SUs existence in the area, links between these SUs are apt to break no matter what channels these SUs choose. CLR recovers all link failures by using clustering method and effectively increases end-to-end throughput and successful packet delivery fraction. The simulation results indicate that CLR increases successful packet delivery ratio and end-to-end throughput. The performance is much superior particularly if there is an intersection area of all PUs’ radio coverage in the network.

A Delay-Awareness Routing Protocol in Intermittently Connected Underwater Acoustic Sensor Networks

Abstract: The rapid development of underwater technology has opened up new possibilities and introduced new challenges for MAC and protocol designs. The packet delay reduction becomes critical issues in underwater sensor networks (USNs) since the propagation speed of water is rather slow compared with radio waves. In addition, due to the property of intermittent link connectivity in underwater, the existing message-based and synchronization-based approaches can not meet packet delivery requirements. In this paper, a tailored multihop routing protocol is designed for transmission delay reduction without packet exchanges and retransmissions. The observation of delivery analysis with different link qualities gives insights on relay nodes selection for lower delivery loss rate. To prevent excessive redundant packets, this work includes a strategy of adjusting the number of packet cloning dynamically between each hop.

QELAR: A Machine-Learning-Based Adaptive Routing Protocol for Energy-Efficient and Lifetime-Extended Underwater Sensor Networks

Abstract: Underwater sensor network (UWSN) has emerged in recent years as a promising networking technique for various aquatic applications. Due to specific characteristics of UWSNs, such as high latency, low bandwidth, and high energy consumption, it is challenging to build networking protocols for UWSNs. In this paper, we focus on addressing the routing issue in UWSNs. We propose an adaptive, energy-efficient, and lifetime-aware routing protocol based on reinforcement learning, QELAR. Our protocol assumes generic MAC protocols and aims at prolonging the lifetime of networks by making residual energy of sensor nodes more evenly distributed. The residual energy of each node as well as the energy distribution among a group of nodes is factored in throughout the routing process to calculate the reward function, which aids in selecting the adequate forwarders for packets. We have performed extensive simulations of the proposed protocol on the Aqua-sim platform and compared with one existing routing protocol (VBF) in terms of packet delivery rate, energy efficiency, latency, and lifetime. The results show that QELAR yields 20 percent longer lifetime on average than VBF.

Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

Abstract: This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols.

A Survey on Underwater Acoustic Sensor Network Routing Protocols

Abstract: Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research.