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—The concept of cognitive radio (or secondary spectrum access) is currently under investigation as a promising paradigm to achieve efficient use of the frequency resource by allowing the coexistence of licensed (primary) and unlicensed (secondary) users in the same bandwidth. According to the property-rights model of cognitive radio, the primary terminals(More)
A scenario with two single-user links, one licensed to use the spectral resource (primary) and one unlicensed (secondary or cognitive), is considered. According to the cognitive radio principle, the activity of the secondary link is required not to interfere with the performance of the primary. Therefore, in this work it is assumed that the cognitive link(More)
—Orthogonal frequency-division multiplexing (OFDM) has been specified by IEEE 802.11a standard as the transmission technique for high-rate wireless local area networks (WLANs). Performance of an OFDM system, however, is heavily degraded by random Wiener phase noise, which causes both common phase error (CPE) and inter-carrier interference (ICI). To mitigate(More)
In this paper, the circular ring model is proposed to model the signal statistics of a wideband multiple-input multiple-output (MIMO) channel. Based on the proposed model, a new space-time-frequency cross-correlation function is derived for the MIMO channel, in a compact mathematical form. The cross-correlation function includes various parameters of(More)
—In this work, a multicell cooperative zero-forcing beamforming (ZFBF) scheme combined with a simple user selection procedure is considered for the Wyner cellular downlink channel. The approach is to transmit to the user with the " best " local channel in each cell. The performance of this suboptimal scheme is investigated in terms of the conventional(More)
For a multiple-input single-output (MISO) downlink channel with M transmit antennas, it has been recently proved that zero-forcing beamforming (ZFBF) to a subset of (at most) M " semiorthogonal " users is optimal in terms of sum-rate, asymptotically with the number of users. However, determining the subset of users for transmission is a complex optimization(More)
— A linear mesh network is considered in which a single user per cell communicates to a local base station via a dedicated relay (two-hop communication). Exploiting the possibly relevant inter-cell channel gains, rate splitting with successive cancellation in both hops is investigated as a promising solution to improve the rate of basic single-rate(More)
—To reduce the computational decoding delay of turbo codes, we propose a parallel algorithm for maximum a posteriori (MAP) decoders. We divide a whole noisy codeword into sub-blocks and use multiple processors to perform sub-block MAP decoding in parallel. Unlike the previously proposed approach with sub-block overlapping, we utilize the forward and(More)