Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Citation - WoS: 2Citation - Scopus: 2Iterative Channel Estimation for Higher Order Modulated Stbc-Ofdm Systems With Reduced Complexity(Korean Society of Internet Information, 2016) Baştürk, İlhan; Özbek, BernaIn this paper, a frequency domain Expectation-Maximization (EM)-based channel estimation algorithm for Space Time Block Coded-Orthogonal Frequency Division Multiplexing (STBC-OFDM) systems is investigated to support higher data rate applications in wireless communications. The computational complexity of the frequency domain EM-based channel estimation is increased when higher order constellations are used because of the ascending size of the search set space. Thus, a search set reduction algorithm is proposed to decrease the complexity without sacrificing the system performance. The performance results of the proposed algorithm is obtained in terms of Bit Error Rate (BER) and Mean Square Error (MSE) for 16QAM and 64QAM modulation schemes.Conference Object Citation - Scopus: 5Queue-Aware Resource Allocation for Ofdma-Based Mobile Relay Enhanced Networks(VDE Publishing House, 2013) Baştürk, İlhan; Özbek, Berna; Le Ruyet, DidierMobile relay assisted OFDMA networks that are considered as a good candidate in future deployment scenarios for coverage extension and lower deployment costs are promising solutions for provision of ubiquitous high-data-rate services in wide coverage areas. However, it is required to design efficient resource allocation algorithms to exploit these opportunities. Thus, this paper designs an heuristic resource allocation algorithm based on the queue and channel state information of the users for mobile relay enhanced OFDMA networks. The proposed queue aware algorithm is appropriate for the realistic scenarios and use system resources efficiently. Numerical results revealed that the mobile-relay enhanced scheme improves coverage and assisting users having unfavorable channel conditions such as cell-edge users by increasing the data rate compared to existing fixed-relay enhanced and non-relaying schemes. © VDE Verlag GMBH.