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Blind source separation (BSS) has been of great interest in many areas such as wireless communications and biomedical imaging. Since many of the existing BSS methods are based on a successive cancellation procedure for extracting all the unknown sources, they suffer not only from the error propagation accumulated at each stage but also from a long processing latency. Chen et al. recently proposed...
In this paper, the puncturing pattern design criteria for rate-compatible punctured turbo (RCPT) codes are reviewed at first. Then the optimal puncturing pattern design problem for RCPT codes are highlighted for turbo codes with specific interleaver instead of the uniform interleaver assumption. By employing the constrained subcode algorithm to calculate the low weight spectrum sequence, the optimized...
In the paper, to solve the problem that some existing methods of separating the weak signals from mixed chaotic signals have to use certain priori knowledge of chaotic signals such as the inherent properties, a FastICA method based on the negentropy is employed to separate the weak signals from the unknown mixed chaotic signals blindly. According to the maximum nongaussianity which is one of the basic...
A two-hop decode-and-forward relay system is considered, which consists of one source, one destination and K relay stations and all the nodes are deployed with multiple antennas. The capacity expressions in the two hops are analyzed and the maximal capacity expressions when signal-to-noise ratio is sufficiently small and sufficiently large are deduced respectively. Based on the capacity expressions,...
Uplink power control is a key radio resource management feature in the 3GPP Long Term Evolution (LTE). In order to adapt to changes in the inter-cell interference situation or to correct power amplifier errors, closed-loop adjustments should be applied. In this paper the performance of closed loop power control combined with fractional path loss compensation factor is studied, and an optimal value...
Spectrum sensing is a key technology in cognitive radio (CR) and cooperative spectrum sensing is derived due to the effects of channel fading. In this paper, we focus on the optimal number of secondary users in cooperative spectrum sensing to maximize the utility in CR network. By considering both the detection error probability and the resource used by the secondary users in cooperation, we derive...
In this paper, we propose an extended semidefinite-relaxation (SDR) method for multiple-input multiple-output (MIMO) detection of high-order QAM signals. In the proposed method, high-order QAM constellations are represented by an equivalent virtually-antipodal form. Based on this form, the alphabet relaxation components in the existing SDR formulation can be constrained to the original alphabet set...
To seek a decoding scheme with good performance, low complexity and fast convergence, we present an improved parallel weighted bit flipping (IPWBF) algorithm for finite geometry low-density parity-check codes whose parity check matrix is of heavy row and column weights. In the IPWBF, a bit flipping (BF) function and two parallel BF criteria, all of which scatter in the literature, are exploited jointly...
System modeling based on conventional mathematical tools is not well suited for dealing with ill-defined and uncertain systems. By contrast, a fuzzy inference system, employing if-then rules can model the qualitative aspects of human knowledge and reasoning processes without employing precise quantitative analyses. This fuzzy identification explored has found numerous practical applications in control,...
Diversity order of linear equalization (LE) is investigated for the case of linearly precoded block transmission in doubly selective channels. A connection between the orthogonal deficiency od(.) of the effective channel matrix at the receiver and an earlier proof that LE achieves full diversity in frequency selective channels is highlighted. For doubly selective channels it is argued that od of the...
Two-way amplify-and-forward relaying is considered in this paper. We propose adaptive power allocation (PA) algorithms to maximize the instantaneous achievable rate and minimize the system outage probability, respectively. Both single- and multi-relay systems are considered. It is shown that the proposed adaptive PA algorithms significantly outperform the uniform PA algorithms. Furthermore, exploiting...
An improved direction-of-arrivals (DOAs) estimation via phase information of sparse solution is presented in this paper. Unlike the conventional sparse source localization approach using the amplitude of sparse solutions only, through a special partition of the receiving data of the sensors, the phase information of the available sparse solutions is also extracted to estimate DOAs. For the true DOAs...
The probability density function and the cumulative distribution function of the product of shifted exponential variates are obtained in terms of the generalized upper incomplete Fox's H function. Using these new results, the exact outage capacity of multi carrier transmission through a slow Rayleigh fading channel is presented. Moreover, it is shown that analytical and simulation results are in perfect...
As M-ary orthogonal code spread-spectrum dispreading method is based on maximum correlation rule, a false dispreading result will be computed out in the situation of false alarm. Moreover, this false result will be handed down to the following units, which of course causes a waste of resources. In this essay, a dispreading method based on confidence analysis is proposed, and the simulation results...
This article proposes a new space time cooperative diversity scheme called full feedback-based cooperative diversity scheme (FFBCD). In contrast to the conventional adaptive space time cooperative diversity schemes which utilize the feedback from only the destination node, the new scheme utilizes the feedback from both the destination node and the cooperation node. With the feedback from the destination...
In this paper, we focus on single-selection opportunistic relaying with the decode-and-forward protocol over Rayleigh fading channels. The end-to-end average signal-to-noise ratios (SNR) and ergodic capacities of both proactive and reactive opportunistic relaying are analyzed as a closed form in a high source-to-relay SNR regime where all link qualities satisfy the required SNR. The derived results...
Spectrum sensing is an essential mechanism in a cognitive radio network. However, the detection performance will be greatly degraded when few untrusted secondary users exist which can be identified as 'Always Yes' users and 'Always No' users. In this paper, we propose an energy detector with double thresholds combined with revised data fusion rules to find these untrusted users and counteract their...
Multiuser diversity can significantly improve wireless system performance by exploiting the feedback information that conveys the channel quality. In multiple input-multiple output and orthogonal frequency division multiplexing (MIMO-OFDM) systems, the per subcarrier on per antenna feedback induces a substantial amount of feedback overload and requires high computational complexity. This paper addresses...
Selection relaying is a promising technique for practical implementation of cooperative systems with multiple relays. However, to select the best relay, globe channel knowledge is required at the selecting entity. In this paper, we consider the relay selection problem in dual-hop amplify-and-forward (AF) communication systems with partial channel state information (CSI). We present relay selection...
In this paper, we proposed a dynamic ordered subcarrier selection algorithm (DOSSA) for OFDM based video transmission system. The proposed scheme is shown to achieve lower bit error rate (BER) than the previously proposed OSSA by first selecting a fraction of the subcarriers with highest channel gain. The content information is then exploited in order to extend the OSSA to achieve unequal error protection...
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