Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

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  • Conference Object
    Çoklu Kullacılı Çgtç-dfbçe Sistemleri için Adil Kaynak Paylaşımı
    (IEEE, 2011) Baştürk, İlhan; Özbek, Berna
    In this study, the user selection at the base station and resource allocation algorithms are presented for multiuser multipleinput single-output orthogonal frequency division multiple access (MU-MISO OFDMA) systems when the number of users in a cell is much more than the number of transmitter antennas. A fair resource allocation algorithm is proposed in order not to victimize the users far from the base stations. In general, Shannon capacity has been shown as the performance measure for MU-MISO-OFDMA systems. In this paper, the bit error rate (BER) is used as an performance metric instead of the Shannon capacity since, increasing the system capacity does not automatically yield the best performance in terms of error rates. It is also shown that the proposed algorithm provides fairness by calculating the fairness index. © 2011 IEEE.
  • Conference Object
    Ofdm Sistemler için Pilot Tabanlı Yinelemeli Kanal Kestirimi
    (IEEE, 2008) Baştürk, İlhan; Özbek, Berna
    In this study, pilot-based iterative channel estimation, which use virtual pilots, is proposed for OFDM systems In order to find final channel estimates, instead of averaging the group estimates, which are found by virtual pilots, it is proposed to combine them by taking into account their reliabilities that are calculated by using probability density function. Then the proposed method is compared to Expectation-Maximization (EM) algorithm with respect to performance and computational complexity. The performance results are given in terms of Bit Error Rate (BER) and Mean Squared Error (MSE). ©2008 IEEE.