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This paper investigates the performance of bidirectional dynamic networks (BDN) with massive multiple input multiple output (MIMO) systems. In BDN, dynamic allocation of the number of uplink and downlink remote radio heads (RRHs) is proposed, which offers a flexible solution to balance the data traffic asymmetry without requiring the time synchronization. Intuitively, the interference between the...
When both access points (APs) and user equipments (UEs) have multiple antennas, the block diagonalization (BD) precoding is preferred for the distributed large-scale multiple-input multiple-output (MIMO) systems. In time division duplexing (TDD) operation, the APs can exploit the estimated uplink channel for downlink joint precoding transmission to simultaneously serve multiple UEs, due to the principle...
This paper considers interference mitigation with power allocation in cognitive radio systems. In such a system, cognitive radio is designed to transmit data to its corresponding users without causing any interference to the current primary transmission. To avoid these interference between these links, the secondary transmitters sense the primary user's unused eigenvector space and reuse these spatial...
This paper investigates the uplink performance of multiple-input multiple-output (MIMO) wireless systems employing linear minimum mean-squared error (MMSE) receivers. We focus on multi-cell MU-MIMO systems with pilot contamination over i.i.d Rayleigh fading channels. The MMSE estimator is adopted to get the CSI and we build the equivalent model of estimated channel for MU-MIMO system with pilot contamination...
In this paper, we study iterative detection algorithms of the multi-cell multi-user massive MIMO systems with pilot contamination. First, a iterative algorithm applying soft decision interference cancellation is introduced. It is based on minimum mean square error (MMSE) filter and derived from [1] where it was applied in block transmission. Then, by considering the algorithm complexity, two iterative...
Network coding with multilevel modulation in distributed antenna systems is analyzed, by which the performance of the uplink can improved due to multiuser diversity. A sample system consist of 2 users with symbol-level network coding is given, where the multilevel modulation is employed at the transmitter, and a kind of maximum ratio combination scheme is used at the receiver. Both the theoretical...
In this paper, we propose a novel iterative approach to bidirectional decision feedback equalization (Bi-DFE). Bi-DFE performs two equalizations, one on the received signal and another on its time-reversed version. The arbitration for the forward and reverse DFEs is decided by minimum path metric in bidirectional Viterbi decoder. In order to further improve the performance of the Bi-DFE, iterative...
In this paper, we present the link level performance of SC-FDMA with SDMA (Space Division Multiple Access), real channel estimation and low complexity frequency-domain turbo equalization. We give the implementation of the minimum-mean-squared-error based turbo equalization which is suitable for DFT-S-OFDM based SDMA systems. The block error rate performance of SC-FDMA and OFDMA with SDMA and turbo...
In this paper, we propose a new approach to bidirectional decision feedback equalization (Bi-DFE) for CDMA systems with low spreading factor. Bidirectional DFE consists of a traditional DFE in parallel with another DFE operating on the time reversed sequence of the received signals. In order to further improve the performance of the proposed Bi-DFE, some modified techniques are applied as follows,...
A joint channel estimation and data detection scheme by using Markov chain Monte Carlo (MCMC) is proposed for MIMO-OFDM systems with multi-tone narrow-band interference (MTNBI). The channel impulse response, the noise variance and the indicator of the impulse noise can be estimated accurately, and then the receiver knows whether the signal is interfered by the narrow band interference. One of the...
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