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The inter-beam interference has been shown to be a critical factor in multi-beam satellite communication systems. This paper proposes a novel pilot sequence design criterion aiming at mitigating the inter-beam interferences. The proposed multi-beam optimality criterion is to minimize the worst-case mean square error (MSE) of an least square (LS) based channel estimator. It is shown that we can obtain...
This paper deals with the joint subcarriers suppression and relay selection (JSSRS) problem in Physical Layer Network Coding (PLNC) based Two-Way Orthogonal Frequency Division Multiplexing (OFDM) relaying system with decode-and-forward protocol over multipath Rayleigh fading channel. Relay selection, which is studied for more than ten years, is a technique used to select one or some relays to improve...
In cognitive radio networks, channel reservation is an effective measure to solve the trade-off problem between dropping probability and blocking probability. Because of the integer nature of channel, most of the current reservation schemes were based on integer. However, the number of reserved channels of integer reservation schemes can't be adequately adjusted as a result of optimizing the system...
The existing spectrum sensing schemes based on free probability theory (FPT) have a high sensing performance especially in cases of low signal to noise ratio (SNR) and a small number of samples. However they all based on data fusion rule when performing cooperative spectrum sensing. The secondary users (SUs), in this case, have to transmit large amounts of sensing data to a fusion center (FC). It...
In cloud computing environment, just protecting the contents of the queries from users to a large database server is far away from enough. Because it does not protect the leak of access patterns from careful observations. It is thus important to make sure the server learning nothing about the queries including access patterns. However, this implies an expensive computation or communication cost of...
Automatic 3D face registration is highly important for 3D face recognition, which can also be used in facial feature segmentation, facial mesh reconstruction, face synthesis and motion capture. In this paper, we propose a coarse-to-fine 3D face registration approach based on template matching of depth images and depth-based active appearance model (AAM). First we construct three multi-angle nose templates...
In a two-tier heterogeneous network with shared spectrum, the cross-tier interference and co-tier interference significantly affect the network performance. In this paper, we investigate a cascaded precoding scheme in orthogonal frequency-division multiplexing systems to protect macro-cell user equipments (MUEs) from the interference caused by co-located small cells and at the same time to satisfy...
In the practical application of cognitive radio network, it is especially important to improve the energy efficiency for those energy-constrained cognitive users. From the perspective of maximizing the energy efficiency in cognitive radio networks, this paper considers the case that the sudden appearance of the primary user can lead to data collision when the cognitive user is transmitting data. Then...
The measurement matrix plays an important role in the hardware implementation of wideband sub-Nyquist sampling. In modulated wideband converter (MWC), the measurement sequences are derived from binary measurement matrix, e.g., random Bernoulli matrix, which can be easily implemented by M ×N shift registers. Utilizing the special cyclic structure, partial circulant measurement matrix only needs N shift...
This paper studies a two-link interference channel (IFC) with simultaneous wireless information and power transfer (SWIPT). We aim to maximize the minimum signal to interference plus noise ratio (SINR) of the two links by jointly designing the power allocations at the transmitters and the power splitting (PS) ratios at the receivers under both the individual minimum energy harvesting (EH) constraints...
In this paper, we present an implementation of OFDM-based underwater acoustic communication transceiver. This transceiver combines the DSP board with a transducer and a hydrophone as the transmitter and receiver, with a power amplifier to adjust various transmit power. We provide a new method based on passband energy analysis for the first-step preliminary signal detection to avoid invalid trigger...
This paper studies he beamforming design problem of a multi-user downlink network, assuming perfect channel state information (CSI) known to the base station (BS). In this scenario, the BS is equipped with multiple antennas, and each user is wiretapped by a specific eavesdropper where each user or eavesdropper is equipped with one antenna. It is supposed that the BS employs transmit beamforming with...
In this paper, we propose a joint power allocation and antenna selection scheme for orthogonal-frequency-division-multiplexing (OFDM) distributed multiple-input multiple-output (D-MIMO) systems. Our aim is to increase energy efficiency (EE), under the constraint of transmission power of each remote access unit (RAU). Because of the multi-objective and non-convex nature of the problem, obtaining the...
In this paper, we investigate the achievable downlink rate of line-of-sight (LOS) multiple-input multiple-output (MIMO) systems, where uniform circular arrays (UCAs) is deployed at Base station (BS). Based on an existing three-dimensional channel model developed by considering both the azimuth and elevation dimensions. We first analyze channel vectors by assuming that users are randomly distributed...
Dynamic channel assignment is a promising solution for flexible and efficient spectrum utilization in a satellite/terrestrial integrated mobile communication system (STICS), that uses multi-beam satellite and share the frequency spectrum allocated to mobile satellite services with terrestrial mobile services. This paper proposes a location based centralized dynamic channel assignment with channel...
MIMO transmission scheme equipped with cross linear polarization antennas has been widely used in mobile radio networks. However, some realistic measurement results show that MIMO scheme equipped with circular polar antennas also has some benefits in live mobile radio networks. In this paper, the penetration capability for linear and circular polarization is studied. Our theoretical analysis shows...
Interference alignment (IA) is an emerging technology for interference management. However, the received signal-to-interference-plus-noise ratio (SINR) may decrease in IA. Opportunistic IA (OIA) schemes can provide more opportunities for the users to access the network and improve the performance; nevertheless, the unselected users remain idle, which is a waste of resource. Thus in this paper, simultaneous...
Location information has become a critical requirement for many applications in wireless sensor networks. Conventional localization requires dense anchors with known positions or high transmit power in sparse networks to reach successful localization, which is not suitable for low-cost and low-power sensors. Cooperative localization is a promising solution for wireless sensors' localization, in which...
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