Arama Sonuçları

Listeleniyor 1 - 4 / 4
  • Yayın
    Jointly optimal chunk and power allocation in uplink SC-FDMA
    (IEEE, 2013) Mert, Teoman; Kaya, Onur; Çırpan, Hakan Ali
    For a single carrier frequency division multiple access (SC-FDMA) system, we obtain the jointly optimal power and chunk allocation policies which maximize the sum rate. Our solution is applicable to both localized and interleaved subcarrier mapping schemes. We solve the joint optimization problem by sequentially solving two sub-problems: power allocation and chunk allocation. Primarily, we use an optimal power allocation algorithm, which we derive from Karush-Kuhn-Tucker (KKT) conditions; and then we convert the optimum chunk assignment problem into a maximum weighted matching problem on a bipartite graph, and hence solve it in polynomial time. We also propose two greedy chunk allocation algorithms with lower complexity, and demonstrate that these algorithms produce near optimal results, especially for interleaved subcarrier mapping, when used in conjunction with optimal power control.
  • Yayın
    Birleşik çöz/sıkıştır ve ilet tabanlı işbirlikçi çoklu erişim
    (IEEE, 2012-04-18) Güneş, Mehmet; Kaya, Onur
    Bu bildiride, iki kullanıcılı bir işbirlikçi çoklu erişim kanalı için çöz-ilet ve sıkıştır-ilet tekniklerinin eş zamanlı kullanılmasına dayalı kodlama ve kodçözme teknikleri geliştiriyor, ve karşılık gelen erişilebilir veri hızı ifadelelerini türetiyoruz. Sonuçlarımızı bilinen bazı çift yönlü işbirliği stratejilerinin veri hızları ile kıyaslayarak, iki tekniğin bir arada kullanılmasının erişilebilir veri hızı bölgesini genişletebildiğini benzetimler yolu ile gösteriyoruz.
  • Yayın
    A sequential Monte Carlo method for blind phase noise estimation and data detection
    (IEEE, 2005) Panayırcı, Erdal; Çırpan, Hakan Ali; Moeneclaey, Marc
    In this paper, a computationally efficient algorithm is presented for blind phase noise estimation and data detection jointly, based on a sequential Monte Carlo method. The basic idea is to treat the transmitted symbols as " missing data" and draw samples sequentially of them based on the observed signal samples up to time t. This way, the Bayesian estimates of the phase noise and the incoming data are obtained through these samples, sequentially drawn, together with their importance weights. The proposed receiver structure is seen to be ideally suited for high-speed parallel implementation using VLSI technology.
  • Yayın
    Space time block code classification for MIMO signals exploiting cyclostationarity
    (Institute of Electrical and Electronics Engineers Inc, 2015) Turan, Merve; Öner, Mustafa Mengüç; Çırpan, Hakan Ali
    Blind and noncooperative identification of the transmission parameters of unknown communication signals has been employed both in military and civilian applications. Multiple-Input-Multiple-Output (MIMO) transmission systems emerging in the last decade pose new challenges to the signal identification systems, one of which is the identification of the Space-Time Block Code (STBC) used in the transmission. In this work, we present a novel STBC classification algorithm that exploits the joint wide sense cyclostationary characteristics of the coded transmit signals as discriminating features. Compared to existing algorithms, the proposed method can discriminate between a large number of different STBCs.