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Full-Text Articles in Engineering

Order-4 Orthogonal Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Zixuan Lin, Le C. Tran, Farzad Safaei Jun 2013

Order-4 Orthogonal Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Zixuan Lin, Le C. Tran, Farzad Safaei

Professor Farzad Safaei

The combination of cooperative communication and Space-Time-Frequency-Codes (STFCs) has been recently proposed in the literature for Multiband OFDM Ultra-Wideband (MB-OFDM UWB) to improve the bit error performance, system capacity, data rate and wireless communications range. This paper proposes a cooperative communication design using Order-4 Orthogonal STFCs in MB-OFDM UWB systems, which is referred to as Order-4 Orthogonal Cooperative Communication Scheme (4-OCCS). It will be shown that 4-OCCS improves significantly the diversity and error performance of the MB-OFDM UWB system, compared to the conventional MB-OFDM UWB (without STFCs) as well as our Order-2 Orthogonal Cooperative Communication Scheme using Alamouti STFCs (2-OCCS) …


Order-4 Quasi-Orthogonal Cooperative Communication In Stfc Mb-Ofdm Uwb, Zixuan Lin, Le Chung Tran, Farzad Safaei, Tadeusz A. Wysocki Jun 2013

Order-4 Quasi-Orthogonal Cooperative Communication In Stfc Mb-Ofdm Uwb, Zixuan Lin, Le Chung Tran, Farzad Safaei, Tadeusz A. Wysocki

Professor Farzad Safaei

Recently, cooperative communication and Space-Time-Frequency-Codes (STFCs) have been introduced into the Multiband OFDM Ultra-Wideband (MB-OFDM UWB) to improve the reliability, data rate and system capacity. This paper proposes a cooperative communication scheme for a four source node MB-OFDM UWB system using Quasi-Orthogonal STFCs, which is referred to as order-4 Quasi-Orthogonal Cooperative Communication Scheme (4-QOCCS). Simulation results show that the proposed 4-QOCCS provides significantly better error performance over the conventional MB-OFDM UWB and our order-2 Orthogonal Cooperative Communication Scheme (2-OCCS) using the Alamouti STFCs, and even better than the order-4 Orthogonal Cooperative Communication Scheme (4-OCCS), which we have been recently proposed, …


Decentralised Task Allocation Under Space, Time And Communication Constraints For Disaster Domain, Xing Su, Minjie Zhang, Quan Bai Jan 2013

Decentralised Task Allocation Under Space, Time And Communication Constraints For Disaster Domain, Xing Su, Minjie Zhang, Quan Bai

Faculty of Engineering and Information Sciences - Papers: Part A

The coordination of dynamic task allocation based on available resources is very challenging in disaster domains under time, space and communication constraints. In addition, it is also very hard or even impossible to achieve tasks allocation by using a centralised manner with the global knowledge of the working environment. This paper presents a novel decentralised coordination approach for dynamic task allocation by considering space, time and communication constraints in a disaster domain, and workloads and priorities of different tasks. In this approach, a group formation mechanism is proposed to help agents with limited communication range to achieve effective task allocation …