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This paper proposes a space-time block coded (STBC) transmission with phase feedback for two-user multi-input multi-output multiple access channels (MIMO-MAC). In the proposed system, the phase feedback is transmitted to only one user, which reduces the overhead of the reverse link. We derive a closed-form solution for the proposed phase feedback, in order to maximize the overall received signal-to-interference-plus-noise...
This paper proposes a low-complexity signal detection algorithm for spatially correlated multiple-input multiple-output (MIMO) channels. The proposed algorithm sets a minimum mean-square error (MMSE) detection result to a starting point, and searches for signal candidates in multi-dimensions of the noise enhancement from which the MMSE detection suffers. The multi-dimensional search is needed because...
The tree representation of the MIMO detection problem is illuminating for the development, interpretation, and classification of various detection methods. One method, based on the Dijkstra's search algorithm, pursues tree exploration according to a bounded, sorted list of tree nodes. Since sorting directly affects tree exploration and truncation in this tree-search method, it is critical to the performance...
We present a low complexity iterative decoding method for a multiplexed Alamouti space-time code serially concatenated by a convolutional code. The space-time signalling code consists of a Gray coded 16-QAM mapper and two spatially overlaid Alamouti signalling blocks. A linear complexity decoder is used for decoding the inner space-time code. Ordinarily, an iterative decoding between the inner and...
In this paper, we propose a Progressive Differential Thresholding (PDT) framework for coordinated network anomaly detection. Under the proposed framework, nodes present on a packet's path progressively encode their opinion (malicious or benign) inside a packet. Subsequent nodes on the path use the encoded opinion as side-information to adapt their anomaly detection thresholds and in turn improve their...
A construction of Grassmannian packings related to representation theory is applied to build implementation-friendly MIMO precoding codebooks when the number of transmit antennas is a power of a prime. Using the chordal distance as a metric, some of the corresponding packings appear to be optimal by meeting the othoplex bound. Also, by using only some of the codewords, smaller packings satisfying...
The turbo detection of a coded under-determined multiple-input multiple-output (UD-MIMO) system is studied in this paper. A UD-MIMO system with transmit antennas and receive antennas has more unknowns than the observations. However, most existing low complexity detectors, such as the vertical Bell Laboratories Layered Space-Time (V-BLAST) or the block decision feedback equalizer (BDFE),...
In this paper, we present a high-performance hybrid linear precoding scheme for the downlink of multiuser multiple-input multiple-output (MU-MIMO) systems based on the combination of an iterative modified regularized block diagonalization (IMRBD) precoding and minimum mean square error (MMSE) precoding. The proposed hybrid diversity maximization (HDM) scheme aims to maximize the diversity gain by...
Dynamic spectrum auction is an effective way to stimulate primary users to lease their idle spectrum and meanwhile solve the competitions among secondary users through bidding. Due to the spatial reusability of spectrum, multiple users which are separate enough can have access to the same spectrum simultaneously without interfering each other. In this paper, we propose a spectrum auction framework...
We present a new MIMO precoding scheme using the LDL^H channel decomposition. The proposed method is verified to have lower complexity and better bit error rate (BER) performance than that of the conventional singular value decomposition (SVD). SVD is commonly used in decomposing the MIMO channel into parallel eigen-modes. However, the large variation of the singular values often leads to ill-conditioned...
This paper presents a multiple-symbol differential spatial division multiple access (MS-DSDMA) system conceived for low-complexity and high-bandwidth-efficiency applications operating in time-varying fading channels, where no channel estimation is required. A low-complexity adaptive multiple-symbol differential interference suppression (MS-DIS) scheme is proposed, which is based on the maximum signal-to-interference-plus-noise...
Frame Synchronization (FS) is required in several communication standards in order to recover the individual frames that have been aggregated in a burst. This paper proposes a low-delay and reduced-complexity Sliding Trellis (ST)-based FS technique, compared to our previously proposed trellis-based FS method. Each burst is divided into overlapping windows in which FS is performed. Useful information...
We propose a novel near-capacity Multiple-Symbol Differential Decoding (MSDD) aided cooperative Differential Linear Dispersion Code (DLDC) scheme, which exhibits a high grade of system design flexibility in terms of relays selection and rate allocation. More specifically, 36-component IRregular Convolutional Code (IRCC) encoded and Unity Rate Coded (URC) differential PSK (DPSK) symbols are transmitted...
The advantage of using channel feedback information to determine the optimal pilot placement is examined for amplify-and-forward OFDM relay links. This work extends upon the previously proposed feedback-aided pilot placement scheme to systems that employ subcarrier pairing at the relay. With channel feedback, the pilot subcarriers can be properly chosen to reduce the channel estimation error and increase...
In this paper, we propose a novel peak to average power ratio (PAPR) reduction scheme of orthogonal frequency division multiplexing (OFDM) signals. In our proposed scheme we exploit the repeated rotation and recombination of the in-phase and the quadrature components of an OFDM symbol in time domain. Our proposed scheme has two main advantages over the previously known scheme such as iterative partial...
Inter-cell co-channel interference (CCI) mitigation is investigated in the context of cellular systems relying on dense frequency reuse. A distributed Base Station (BS) cooperation aided soft reception scheme using the Probabilistic Data Association (PDA) algorithm and Soft Combining (SC) is proposed for the uplink of multi-user multi-cell MIMO systems. The realistic hexagonal cellular model relying...
Motivated by the noncoherent subspace coding approach and the low-complexity sparse coding approach to realize random linear network coding, we consider the problem of characterizing the probability of having a full rank (or nonsingular) square transfer matrix over a finite field, for which the probability of choosing the zero element is different from that of choosing a nonzero element. We found...
The paper studies the construction of error-estimation-codes (EEC), which estimate the bit-error-rate (BER) of packet transmissions. The concept of EEC was first proposed by Chen et.al in SIGCOMM 2010. In the same work group-sampling-error-estimation-codes (GSEEC) were constructed. Assuming the packet length is n, GSEEC requires communication overhead O(log(n)) and coding complexity O(n) to reliably...
In this paper, joint optimization of subcarrier pairing, relay selection and power allocation is formulated through a capacity maximization problem in orthogonal frequency division multiplexing (OFDM) relay systems, with fairness considerations and individual power constraint on each node. Because achieving the optimal solution is computationally demanding, which is resulted from the excessive possibilities...
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