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The Kronecker model Is a popular structure In the design and analysis of multiple-input multiple-output (MIMO) systems. Despite being criticized for unrealistic results in some cases, it mathematically facilitates the analysis of MIMO transmission schemes. In our earlier work [1], we proposed algorithms in order to determine a MIMO channel covariance matrix which is as far as possible from the Kronecker...
This paper studies the selective forwarding attacks in wireless sensor networks (WSNs) and proposes a method to detect selective forwarding attacks based on digital watermarking technology. This method embeds watermark into the source data packets, which will be extracted at the base station (BS). The BS will judge whether there are malicious nodes in the transmission path by analyzing the packet...
A novel zone based downlink frequency planning scheme in relay enhanced cellular systems is proposed in this paper. There are two basic frequency planning methods for relay nodes in one cell: spectrum sharing which can avoid intra-cell interference between relay nodes to improve channel quality; spectrum reusing which can increase amount of available channels for each relay node. Neither of these...
The extreme value theory and the assumption that lattice orthogonal frequency division multiplexing (LOFDM) signal converges weakly to a Gaussian random process are employed to derive peak-to-average-power ratio (PAPR) in LOFDM systems. Two complementary cumulative distribution functions (CCDF) of LOFDM system with equal and unequal subcarrier power allocation are given, respectively. Computer simulations...
Transmit power control in wireless networks has long been recognized as an effective mechanism to mitigate co-channel interference. The optimal transmit power control problem is typically non-convex if a system utility is to be maximized. In our recent work [1], we proposed a distributed algorithm, referred to as GLAD, that obtains the global optimal solution to the non-convex power control problem...
A new robust beamforming method is proposed for signal steering vector errors and moving jammers. This method is based on the minimum variance distortionless response (MVDR) method. Under the premise of knowing signals' DOA information, the signal-free covariance matrix is constructed in order to solve the signal steering vector mismatch problem. Each jammer from a single direction is changed into...
Based on queuing theory and game analysis, a distributed channel allocation algorithm for secondary users in cognitive wireless networks is proposed. Compared with prior works, the first contribution in this paper is the iterative process with dynamic adjustment step. In traditional strategy adjustment algorithm, the adjustment step is set as fixed, this may cause the periodic oscillation. Another...
Matched field processing (MFP) is generalized beamforming method which utilizes the physics of wave propagation in the ocean waveguide to estimate the range, depth and azimuth of the sources or inversion the waveguide. Traditional MFP only uses the pressure information of the sound field. The vector sensor measures the pressure and three orthogonal components of the particle velocity simultaneously...
In this paper, a synthesized algorithm for flaw classification in ultrasonic guided waves signal is presented, in which Wavelet Transform is utilized in the process of noise suppression and envelop extraction, and the Probabilistic Neural Network (PNN) is introduced for flaw classification of the ultrasonic testing signal. Besides, in the process of feature extraction, the necessity of attenuation...
The spatial scrambling based secure wireless transmission methods, such as artificial noise and antenna array weighted randomly, can secure wireless transmission at the physical layer. They have a common physical essence, that is, the private message is transmitted in the desired direction while deliberate interference is transmitted in other orthogonal directions. Unfortunately, the interference...
For a two user's interference channel with slow flat fading, in this paper, different ML-decoders are designed basing on information at receivers. For each decoder, analysis of performance based on pair-wise error probability is given, and also comparisons on the performances are made. Analysis shows that, information at the decoder about the co-user's codebook is of key importance to overcome the...
Cognitive radio (CR) technology has been attracted as a solution for the frequency scarcity problem in the wireless mesh network which operates on multiple frequency bands (or channels). In this paper, we consider the channel assignment and routing in CR-based wireless mesh networks (CRWMNs). In the CRWMN, CR nodes access the channels without disturbing primary users (PUs) which have a privilege to...
With the development of the network scale, energy saving has become an important issue in mobile communication network. This paper introduces an energy saving strategy for LTE HetNet with overlapping picos, which uses the remaining resources of neighboring picocells and macrocell to accept the users of picocell to be switched off. Simulations show that the proposed energy saving algorithm has better...
It has been well recognized that the capacity of a wireless system is usually limited because of intracell interference and intercell interference (ICI), and many technologies have been used to combat against them in different systems. Here, we consider a closed-loop wireless network with a limited feedback rate. In such networks, channel state information (CSI) feedback has become a well recognized...
This paper proposes a novel scheme, based on progressive fountain codes, for broadcasting JPEG 2000 multimedia. In such a broadcast scheme, progressive resolution levels of images/video have been unequally protected when transmitted using the proposed progressive fountain codes. With progressive fountain codes applied in the broadcast scheme, the resolutions of images (JPEG 2000) or videos (MJPEG...
In this paper, we investigate the downlink spectral efficiency of infrastructure relay-enhanced cellular systems. In particular, we use the average achieved spectral efficiency at an arbitrary mobile receiver in presence of co-channel interference, termed as cell spectral efficiency (CSE), to quantify the benefit of relay transmission in terms of lower co-channel interference power. We derive the...
Analytically studying the overall outage performance of two-way amplify-and-forward (AF) relaying systems has always been a difficult task. In this paper we study the overall outage probability (OOP) for the two-way amplify-and-forward (AF) relaying system. The channels are independent but not identically Nakagami-m fading distributed. We obtain the tight closed-form OOP approximated expression for...
Physical-layer Network Coding (PNC) has shown its power for improving the throughput effectively of the bi-directional relay system. Most of the existing PNC schemes are carried out under the assumption of perfect synchronization. In this paper, we provide some new insights into the joint design of Low-Density Parity-Check (LDPC)-coded and PNC for asynchronous bi-directional relay system with BPSK...
Due to its radial velocity, the range walk (linear term of range migration) of a moving target in synthetic aperture radar (SAR) image is usually bigger than that of the stationary target. Hence in the time domain after range cell migration correction, the trajectory of most moving target is usually characterized by an approximate sloping line, while the trajectory of stationary targets is lines parallel...
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