Browsing by Author "Yu, Chih-Min"

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A Multi-Objective Model Checking for Transmission Policy Optimization in Hybrid Powered Small Cell Networks
(2020-01-01)
Yu, Chih-Min
;
Tala't, Mohammad
;
Shen, Li-Hsiang
;
Kai-Ten Feng
;
電機工程學系
In the fifth generation (5G) communication system, maximizing energy utilization is one of the key challenges especially with limited green energy sources. In particular, it is important to determine the optimal transmission policy for the hybrid model with grid and green energy in small cell networks. The optimal transmission policy should minimize both grid power consumption and wastage of green harvested energy at the same time; while satisfying the quality of service (QoS) requirements such as minimum packet drop probability. In contrast to existing policies with a single objective for the hybrid powered small cell networks, the proposed transmission policy adopts a multi-objective model checking for Markov decision process (MOMC-MDP) with a linear temporal logic (LTL) scheme. The MOMC-MDP firstly determines all feasible decisions for packet transmissions in every time slot, and then chooses one of the best feasible decisions to obtain the optimal transmission policy. Three dimension Markov decision process (3D-MDP) that includes packet buffer, battery capacity, and channel state, are used with the age of information (AoI) of the packet arrivals to improve the overall performance of the proposed MOMC-MDP scheme. Numerical results validate that the proposed MOMC-MDP with AoI can provide higher green energy utilization compared to the conventional MDP-based schemes.
A Reconfigurable Formation and Disjoint Hierarchical Routing for Rechargeable Bluetooth Networks
(2016-05-01)
Yu, Chih-Min
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Lee, Yi-Hsiu
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電信工程研究所
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Institute of Communications Engineering
In this paper, a reconfigurable mesh-tree with a disjoint hierarchical routing protocol for the Bluetooth sensor network is proposed. First, a designated root constructs a tree-shaped subnet and propagates parameters k and c in its downstream direction to determine new roots. Each new root asks its upstream master to start a return connection to convert the first tree-shaped subnet into a mesh-shaped subnet. At the same time, each new root repeats the same procedure as the designated root to build its own tree-shaped subnet, until the whole scatternet is formed. As a result, the reconfigurable mesh-tree constructs a mesh-shaped topology in one densely covered area that is extended by tree-shaped topology to other sparsely covered areas. To locate the optimum k layer for various sizes of networks, a peak-search method is introduced in the designated root to determine the optimum mesh-tree configuration. In addition, the reconfigurable mesh-tree can dynamically compute the optimum layer k when the size of the network changes in the topology maintenance phase. In order to deliver packets over the mesh-tree networks, a disjoint hierarchical routing protocol is designed during the scatternet formation phase to efficiently forward packets in-between the mesh-subnet and the tree-subnet. To achieve the energy balance design, two equal disjoint paths are generated, allowing each node to alleviate network congestion, since most traffic occurs at the mesh-subnet. Simulation results show that the joint reconfigurable method and routing algorithm generate an efficient scatternet configuration by achieving better scatternet and routing performance than BlueHRT (bluetooth hybrid ring tree). Furthermore, the disjoint routing with rechargeable battery strategy effectively improves network lifetime and demonstrates better energy efficiency than conventional routing methods.
A Survey: Green Energy for Cellular Base Station and Small Cell
(2017-01-01)
Tala't, Mohammad
;
Yu, Chih-Min
;
Feng, Kai-Ten
;
電機工程學系
;
Department of Electrical and Computer Engineering
Recently green energy is one of the promising solutions for wireless communication to decrease the power consumption in term of reducing foot carbon emissions. One of the high challenges is to find the optimal solution for wireless communication especially heterogeneous networks taking into account maintaining the quality of service (QoS) of the connection. This paper investigates several methods to find the optimal solution for the heterogeneous network including cellular base station and small cell base stations (SBSs) using renewable energy. We present briefly the recent methods and policies to achieve the optimal solution. Lastly, we suggest some ideas that it can efficiently improve the performance of current solutions with guaranteed QoS.
Introduction to blueweb: A decentralized scatternet formation algorithm for Bluetooth ad hoc networks
(2008-09-01)
Yu, Chih-Min
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Huang, Chia-Chi
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電信工程研究所
;
Institute of Communications Engineering
In this letter, a decentralized scatternet formation algorithm called Bluelayer is proposed. First. Bluelayer uses a designated root to construct a tree-shaped subnet and propagates an integer variable k 1 called counter limit as well as a constant k in its downstream direction to determine new roots. Then each new root asks its upstream master to start a return connection procedure to convert the tree-shaped subnet into a web-shaped subnet for its immediate upstream root, At the same time, each new root repeats the same procedure as the root to build its own subnet until the whole scatternet is formed, Simulation results show that Bluelayer achieves good network scalability and generates an efficient scatternet configuration for various sizes of Bluetooth ad hoc network.
Joint Balanced Routing and Energy Harvesting Strategy for Maximizing Network Lifetime in WSNs
(2019-06-02)
Yu, Chih-Min
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Tala't, Mohammad
;
Chiu, Chun-Hao
;
Huang, Chin-Yao
;
電機工程學系
Nowadays, wireless sensor networks (WSNs) are becoming increasingly popular due to the wide variety of applications. The network can be utilized to collect and transmit numerous types of messages to a data sink in a many-to-one fashion. The WSNs usually contain sensors with low communication ability and limited battery power, and the battery replacement is difficult in WSNs for large amount embedded nodes, which indicates a balanced routing strategy is essential to be developed for an extensive operation lifecycle. To realize the goal, the research challenges require not only to minimize the energy consumption in each node but also to balance the whole WSNs traffic load. In this article, a Shortest Path Tree with Energy Balance Routing strategy (SPT-EBR) based on a forward awareness factor is proposed. In SPT-EBR, Two methods are presented including the power consumption and the energy harvesting schemes to select the forwarding node according to the awareness factors of link weight. First, the packet forwarding rate factor is considered in the power consumption scheme to update the link weight for the sensors with higher power consumption and mitigate the traffic load of hotspot nodes to achieve the energy balance network. With the assistance of the power consumption scheme, hotspot nodes can be transferred from the irregular location to the same intra-layer from the sink. Based on this feature, the energy harvesting scheme combines both the packet forwarding rate and the power charging rate factors together to update the link weight with a new battery charging rate factor for hotspot nodes. Finally, simulation results validate that both power consumption and energy harvesting schemes in SPT-EBR achieve better energy balance performance and save more charging power than the conventional shortest path algorithm and thus improve the overall network lifecycle.
Joint Component Carrier and Antenna Allocation for Heterogeneous Network in LTE-A System
(2014)
Lee, Yi-Hsiu
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Yu, Chih-Min
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Feng, Kai-Ten
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Lin, Jia-Shi
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電機工程學系
In this paper, a novel multi-carrier and multi-antenna for a multi-tier cellular network is presented for Long-Term Evolution Advanced (LTE-A) heterogeneous networks (HetNets) with carrier aggregation enhancement. First, we investigate a system model of frequency domain load balancing-based inter-cell interference coordination (ICIC) to minimize the total interference, while satisfying the required quality of service constraints. To achieve the desired system performance, a heuristic solution by joint spectrum and antenna allocation is then proposed, which operates at the base station side to enable efficient interference management. The optimal deployment for component carriers and antennas at the serving base station is updated for specific time periods while passively receiving the system information transmitted from neighboring base stations. Furthermore, system level simulations are carried out to demonstrate how the throughput can be greatly improved by our solution, as compared to conventional methods such as the randomized and static ICIC approaches.
On hybrid energy utilization for harvesting base station in 5G networks
(1970-01-01)
Yu, Chih-Min
;
Tala't, Mohammad
;
Feng, Kai-Ten
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, hybrid energy utilization was studied for the base station in a 5G network. To minimize AC power usage from the hybrid energy system and minimize solar energy waste, a Markov decision process (MDP) model was proposed for packet transmission in two practical scenarios. In this model, one buffer is transmitted with a given number of data packets over finite transmission time intervals. In the two scenarios of packet transmission, solar energy harvesting (SEH) is stored in the first scene, while the other scene uses the energy immediately. The MDP model determines the best actions and decisions for both scenarios. When considering a finite battery size and finite packet buffer, the MDP model defines the actions, states, state transition probabilities, and cost value for each action. In the first scenario, the received solar energy harvester will not be used if it is not enough to transmit the packets in the buffer. In the second scenario, the received solar energy harvester will be used immediately. In both scenarios, the cost value is the weighted sum of AC power and SEH wastage. The simulation results showed the optimum buffer sizes could be determined for the balance between AC power consumption and SEH wastage based on the cost value of the proposed model. Finally, the numerical results indicated that the proposed MDP model could reduce AC power usage by up to 50%.
On Hybrid Energy Utilization in Wireless Sensor Networks
(2017-12-01)
Tala't, Mohammad
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Yu, Chih-Min
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Ku, Meng-Lin
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Feng, Kai-Ten
;
電機工程學系
In a wireless sensor network (WSN), many applications have limited energy resources for data transmission. In order to accomplish a better green communication for WSN, a hybrid energy scheme can supply a more reliable energy source. In this article, hybrid energy utilization-which consists of constant energy source and solar harvested energy-is considered for WSN. To minimize constant energy usage from the hybrid source, a Markov decision process (MDP) is designed to find the optimal transmission policy. With a finite packet buffer and a finite battery size, an MDP model is presented to define the states, actions, state transition probabilities, and the cost function including the cost values for all actions. A weighted sum of constant energy source consumption and a packet dropping probability (PDP) are adopted as the cost value, enabling us to find the optimal solution for balancing the minimization of the constant energy source utilization and the PDP using a value iteration algorithm. As shown in the simulation results, the performance of optimal solution using MDP achieves a significant improvement compared to solution without its use.
On the architecture design and performance evaluation of a configurable Blueweb network
(2007-05-01)
Yu, Chih-Min
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Huang, Chia-Chi
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電信工程研究所
;
Institute of Communications Engineering
Blueweb is a self-organizing Bluetooth-based multihop network equipped with a scatternet formation algorithm and a modified source routing protocol. In this paper, we first review the basic Blueweb network. Then we focus on a heuristic automatic configuration algorithm which can be used to partition a large-scale Blueweb network. This algorithm contains three main functional blocks including route master selection, node assignment, and subnet number decision. The route master selection block selects new route masters at a low computation cost. The node assignment block assigns nodes to each newly configured subnet in order to minimize the average route query cost. The subnet number decision block determines the optimal number of subnet which achieves the largest system performance improvement ratio at minimum operation cost. With these three functional blocks, optimal network configuration for Blueweb routing protocol can be determined. Computer simulations show that a configured Blueweb achieves higher network capacity than an unconfigured Blueweb.
Optimal Transmission Policy for Maximizing Green Energy Utilization in Small Cell Networks
(2019-01-01)
Tala't, Mohammad
;
Shen, Li-Hsiang
;
Yu, Chih-Min
;
Feng, Kai-Ten
;
電機工程學系
Transmission policy of the hybrid energy model allows maximizing energy utilization of small cells in the wireless system. One of the key challenges in maximization of energy utilization is to minimize the grid power and energy wastage of green harvested energy (GHE) sources simultaneously. In this paper, unlike existing transmission policy solution which focuses only on one highlighted objective, we proposed multi-objective model checking for Markov decision process (MOMC-MDP) with linear temporal logic (LTL) to find the best feasible solution for packet transmissions in each time slot. Based on the MOMC-MDP for different battery status, the optimal transmission policy of small cells is obtained in order to deliver the highest harvest energy sources and guarantee the quality of service (QoS) demands. Numerical results show that the MOMC-MDP scheme can ensure to efficiently use the limited energy of battery while maximizing green energy utilization in real-time transmission.
Renewable Energy-Based Resource Allocation for Full-Duplex Small Cell Networks
(2018-01-01)
Yafis, Balqis
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Feng, Kai-Ten
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Yu, Chih-Min
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電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, a renewable energy-based resource allocation method is proposed for full-duplex small cell networks. This method presents an outage-aware power allocation scheme as an optimal transmission policy for a two-way communication system between a base station and user equipment (UE) in one single small cell network, where each node is solar-powered and equipped with a finite capacity battery. A full-duplex (FD) scheduling scheme is presented by utilizing Markov decision process (MDP) action parameters to maximize throughput and minimize outage probability. With two different techniques, scheduling and power transmission, the MDP action sets are formulated to maximize the reward function. Outage probability is investigated by comparing our proposed FD scheme to the conventional half-duplex scheme. Furthermore, the throughput performance of the FD scheme is investigated by varying the scenarios. Finally, the outage probability and throughput performance of the FD scheme are demonstrated, in which the FD scheduling scheme has achieved 87.5 % capacity, and the outage probability is linearly decreased and degraded at 15 dB of SNR. However, with the constraint of a five-meter distance between the UE and interferers, the simulation results show that our proposed optimal transmission policy outperforms the half-duplex system despite dealing with intra-cell interference, inter-cell interference, and limited battery power.