Browsing by Author "Chen, Chia-Yao"

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A cross-layer error correction scheme based on multiple-CRC in OFDM/OFDMA wireless networks
(2013)
Chen, Chia-Yao
;
Jia, Wen-Kang
;
Chen, Yaw-Chung
;
資訊工程學系
;
Department of Computer Science
The orthogonal frequency division multiplexing access (OFDM/OFDMA) based wireless transmission technology has been widely deployed in recent years. The frame check sequence (FCS) scheme is employed to enhance the reliability of OFDM/OFDMA systems. Since the padding overhead cannot be effectively avoided in OFDM/OFDMA when medium access control frames are encapsulated, we propose a novel cyclic redundancy check based error correction scheme by utilizing the padding space to carry extra segmented FCS information as much as possible; compared with the legacy FCS scheme, our approach greatly enhance the error detection and correction upon the first retransmission (second transmission). A significant performance improvement based on the simulation results is also demonstrated.
A Redundancy-Free Reliable Multicast in Wireless Multi-hop Relay Networks
(2011)
Chen, Chia-Yao
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Jia, Wen-Kang
;
Yang, Yuan-Rung
;
Chen, Yaw-Chung
;
資訊工程學系
The Orthogonal Frequency Division Multiplexing Access (OFDM-based) wireless transmission technology is widely deployed nowadays, and Frame Check Sequence (FCS) scheme is used to enhance the reliability of OFDM-based systems. Since the padding overhead cannot be effectively avoided in OFDM-based system when MAC frames are encapsulated, we propose a novel CRC based error correction scheme by utilizing the frame padding overhead to carry extra segmented FCS information as much as possible; compared with legacy FCS scheme, our approach achieves a significant improvement in error detection and correction for the multicast frame in transparent mode multi-hop relay network. We demonstrate a significant performance improvement based on the mathematical analysis.
ALEX: An Arithmetic-based Unified Unicast and Multicast Routing for MANETs
(2014)
Jia, Wen-Kang
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Chen, Chia-Yao
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Chen, Yaw-Chung
;
資訊工程學系
;
Department of Computer Science
Explicit multicasting protocols such as Differential Destination Multicast (DDM) in MANETs have been retaining advantages of traditional approach while eliminating their shortcomings especially for small-group applications. However, they still have some drawbacks especially in the group size limitation. In this work we discussed a new unified unicast and multicast routing scheme called Arithmetic Labeled EXplicit (ALEX) Multicast Routing based on arithmetic encoding of on tree node keys and recursive unicast for MANETs. Our scheme constructs the multicast tree by decoding the bitmap of its output ports for next hops in the forwarding path using a common Multicast Channel Mentifier (MCID) and a node-specific key, so that multicast packets can be self-routed to multiple receivers without requiring header modification, and intermediate nodes on the multicast mesh will be stateless. In addition to scaling up the multicast group size, our scheme can reduce the processing complexity, control overhead and delivery latency comparing to the existing works. The simulation results indicated that our proposed scheme achieves a remarkable improvement in scalability while simplifying the deployment and management for a large number of medium-size multicast groups in MANETs.
PSFCS: Robust Emergency Communications Supporting High Mobility Based on WiMAX MMR Networks
(2014)
Jia, Wen-Kang
;
Chen, Chia-Yao
;
Chen, Yaw-Chung
;
資訊工程學系
;
Department of Computer Science
Nowadays public safety networks are widely deployed to support highly reliable wireless communications in case of emergency. The adoption of standardized systems such as WiMAX for emergency communications represents a significant advance in the off-the-shelf technologies for error detection and error correction. Since it is difficult to fully eliminate the Doppler effect under high speed moving environment, we propose an enhanced CRC-based error correction scheme that carries as much extra segmented frame Check Sequence (FCS) information as subblocks of emergency multicast/broadcast service (MBS) frame, called progressive and selective frame check sequence (PSFCS). In a mobile multihop relay (MMR) environment, a high-mobility mobile station might receive an emergency MBS frame more than once, so the PSFCS could be cross-referenced by duplicated frames received. Therefore the PSFCS achieves a significant performance improvement over the legacy FCS scheme in terms of error detection and correction of emergency MBS frames in a WiMAX MMR network operating in transparent mode. The experimental results show that the goodput and utilization of high-mobility mobile stations can be improved remarkably.
TDPBU: Route Optimization for Coexisting Mobility Managements in IPv6 Networks
(2011)
Jia, Wen-Kang
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Chen, Chia-Yao
;
Yang, Yuan-Rung
;
Chen, Yaw-Chung
;
資訊工程學系
Client-based Mobile IPv6 (MIPv6) is the most well known mobility management protocol, and the fast emerging proxy-based Mobile IPv6 (PMIPv6) offers an alternative. Some inherent problems such as route optimization in these protocols have not been really solved. Although various proposals tried to tackle the route optimization problem, none of them has achieved a real success. Furthermore, most of them are not comprehensive solutions for coexisting MIPv6/PMIPv6 mobile environment. In this paper, we proposed a novel unified route optimization scheme - Traffic Driven Pseudo Binding Update (TDPBU) to accommodate various mobility management issues. We evaluated our proposed scheme through simulations, and numerical results show that TDPBU can significantly improve the overall performance of mobility management protocols.