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Most existing studies on two-way relay networks (TWRNs) typically assume that the channels are reciprocal. However, in time-frequency dispersive channels, the channels between the multiple access channel phase and broadcast channel phase become highly non-reciprocal, which significantly complicates the indispensable channel estimation for TWRNs employing coherent detection. In this paper, the challenging...
This paper investigates the joint power control and transmit beamforming problem in multiuser cognitive radio systems (CR). Comparing to the conventional downlink transmit problems, joint power management and beamforming schemes in CR systems is more complicated because designers must take the interference to primary users (PUs) into consideration. Assuming perfect channel information to both CR users...
In this paper, a partial-band jamming suppression algorithm is proposed for a slow frequency hopping system with continuous phase modulation (CPM). The algorithm is based on a non-coherent iterative maximum a posteriori (MAP) detection and the jamming state information (JSI) estimation. The simulation results demonstrate that the algorithm performs well for the partial-band jamming suppression. Moreover,...
In this paper, we present an improved iterative interchannel interference (ICI) cancellation and signal detection technique for orthogonal frequency division multiplexing (OFDM) system on fast time-varying fading channel with nonintegral-delay. As a consequence of the time-varying channel, the orthogonality of subcarriers is destroyed, resulting in interchannel interference (ICI), which increases...
The existed preamble structure for orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) system requires two zero-value guard symbols to guarantee ISI and ICI avoidance (equivalent to 3/2 complex value symbols in OFDM with cyclic prefix system), which leads to OFDM/OQAM system with low spectrum efficiency. In this paper, we shorten the preamble with 1 zero-value guard symbol to improve the...
In this paper, we proposed a partial-band jamming suppression algorithm especially for a slow frequency hopping system. In this system, continuous phase modulation (CPM) is adopted, and the algorithm is based on the iterative noncoherent CPM detection and the jamming state information (JSI) estimation. The complexity of the system is reduced by iterative tree search scheme rather than the exhaustive...
In this paper, we address the problem of channel estimation in time-variant multi-path environment in Orthogonal frequency division multiplexing systems(OFDM). Based on the assumption that the channel varies in a linear fashion during an OFDM block duration, a novel iterative channel estimation arithmetic with noise and interference suppression using pilot tones is investigated. Through iterative...
Spectrum sensing is a key technology in cognitive radio (CR). It provides the CR system with available vacant channels list by sensing the spectrum environment over a wide frequency band. However, local sensing by single node will be compromised if the sensing node experiences shadowing or fading effect. Cooperative spectrum sensing is derived to solve this problem. In this paper, we propose an adaptive...
A reduced-complexity minimum mean square error (MMSE) soft interference cancellation (SIC) based multiple-input multiple-output (MIMO) turbo receiver is proposed. In this new proposal, the computational complexity intensive part of the MMSE SIC detector is ignored if the reliability of the a priori information is larger than a specific threshold. As the co-antenna interference (CAI) of MIMO system...
Iterative soft-in/soft-out (SISO) minimum mean squared error (MMSE) soft interference cancellation (SIC) detector has been successfully applied to V-BLAST turbo receiver. To reduce the computation complexity, an iterative SISO SIC detector combined MMSE with match filter (MF) has been proposed. In this paper, we simplify the SISO MF SIC detector and propose two turbo receiver schemes, in which MMSE,...
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