Nikolaos I. Miridakis

Nikolaos I. Miridakis, Dimitrios D. Vergados

The performance of the V-BLAST approach, which utilizes successive interference cancellation (SIC) with optimal ordering, over independent Nakagami-m fading channels is studied. Systems with two transmit and n receive antennas are employed whereas the potential erroneous decision of SIC is also considered. In particular, tight closed-form bound expressions are derived in terms of the average symbol error rate (ASER) and the outage probability, in case of binary and rectangular M-ary constellation alphabets. The mathematical analysis is accompanied with selected performance evaluation and numerical results, which demonstrate the usefulness of the proposed approach.

Nikolaos I. Miridakis, Dimitrios D. Vergados, Emmanouil Papadakis

In this letter, following a cross-layer design concept, we propose a novel subcarrier grouping technique for Orthogonal Frequency and Code Division Multiplexing (OFCDM) multiuser systems. We adopt a two dimensional (2D) spreading, so as to achieve both frequency- and time-domain channel gain. Furthermore, we enable a receiver-centric approach, where the receiver rather than a potential sender controls the admission decision of the communication establishment. We study the robustness of the proposed scheme in terms of the Bit-Error-Rate (BER) and the outage probability. The derived results indicate that the proposed scheme outperforms the classical OFCDM approach.

Stylianos P. Savaidis, Nikolaos I. Miridakis

Present work proposes a theoretical statistical model of the downlink power consumption in cellular CDMA networks. The proposed model employs a simple but popular propagation model, which breaks down path losses into a distance dependent and a log-normal shadowing loss term. Based on the aforementioned path loss formalism, closed-form expressions for the first and the second moment of power consumption are obtained taking into account conditions placed by cell selection and handoff algorithms. Numerical results for various radio propagation environments and cell selection as well as handoff schemes are provided and discussed.