Learn More
A frequency-hopping (FH) space-frequency (SF)-coded clustered orthogonal frequency division multiple access (OFDMA) system is considered. It is shown that SF coding reduces the number of collisions in OFDMA with FH provided that the subcarrier clusters are formed randomly at each hopping instant. Analytical expressions for the collision rate, which is(More)
We propose a novel system architecture that employs a matching pursuit-based basis selection algorithm for directions of arrival estimation. The proposed system does not require a priori knowledge of the number of angles to be resolved and uses very small number of snapshots for convergence. The performance of the algorithm is not affected by correlation in(More)
Performance of wireless local area networks (WLANs) over fiber systems is investigated under multipath fading for different graded index fiber profiles and optical system imperfections. The effect of OFDM cyclic prefix to the multimode fiber dispersion is investigated for the first time. Comparison of the WLAN over fiber systems operating at 5 GHz and 60(More)
Introduction: For wireless communication systems where it is not feasible to deploy multiple antennas at the receiver, transmitter diversity offers a powerful alternative. Many techniques incorporating space-time (ST) coding have been proposed in recent years (see e.g. [1] and the references therein). Alternatively, signal space diversity combats fading by(More)
A frequency hopping, space-frequency coded clustered orthogonal frequency-division multiple access (OFDMA) system is considered. It is shown analytically that SF coding reduces the number of collisions in OFDMA with random subcarrier hopping. Expressions for the expected number of symbol loss in a cluster collision are derived. Bit error rate computations(More)
A methodology for doubling the throughput of multi-carrier systems is proposed. Throughput enhancement method is introduced by using pulse shaping in multi-carrier systems. By employing more than one WeylHeisenberg frames that are orthonormal both within the frame and in between the frames, the throughput of multi-carrier systems is increased. Different(More)
Cognitive radio (CR) is an emerging technique to improve the utilization of radio frequency spectrum in wireless communication networks. In this paper, we consider the problem of throughput maximization of spectrum allocation in cognitive radio networks. Furthermore, with increasing power level of secondary transmitters, primary receivers are affected by(More)
The performance of an IEEE 802.16 based OFDMA network is simulated employing real geographical and base station data. The effects of soft handover, smart antennas, and transmit diversity on system performance are presented. In particular, the relationship between power control and adaptive modulation is investigated and shown to reduce the uplink(More)
In this paper, we present a novel optical CDMA multi-user detector employing the orthogonal matching pursuit algorithm. The proposed system is compared with most of the receiver structures in the literature. It is shown by simulation results that the proposed detection architecture is a very promising candidate with its low computational complexity, and(More)
OFDM/OQAM is a promising radio access technique for high data-rate fourth generation cellular systems, operating on time and frequency dispersive wireless channel. Contrary to the well established OFDM/QAM, it allows very well localized prototype waveforms to be used for critical unit-density time-frequency lattices, offering maximal spectrum efficiency.(More)