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This paper proposes a distributed cooperative framework to improve the energy efficiency of green cellular networks. Based on the traffic load, neighboring base stations (BSs) cooperate to optimize the BS switching (sleeping) strategies so as to maximize the energy saving while guaranteeing users' minimal service requirements. An interaction graph is defined to capture the network impact of the BS...
In this work, we propose a dynamic distributed resource sharing scheme which jointly considers mode selection, resource allocation, and power control in a unified framework for general D2D communications. Specifically, we model the joint problem of mode selection and resource allocation as a hedonic coalition formation game, and develop a coalition formation process based on the switch rule. Through...
Driven by the great performance improvement using flexible combination of omnidirectional and directional antennas, wireless mesh networks (WMNs) with hybrid antenna mode have become a promising technology for providing users with better network service. Since multimedia contents account for most of the network traffic, content delivery is a big issue when designing network protocols. By combining...
In cognitive radio sensor networks, one of the fundamental tasks is cooperative spectrum sensing by multiple cognitive radio (CR) sensors to improve the spectrum detection performance. However, during each cooperative sensing process, extra energy is consumed by the selected sensors through local sensing, data reporting, and data fusion activities. Thus, cooperative sensing processes call for energy...
In this paper, we aim to optimize the secrecy rate of the cellular user (CU) in a single cell where the Device-to-Device (D2D) communication shares the uplink resource with CU. The interference link from CU to the D2D receiver can be considered as the eavesdropping link in the sense that the D2D receiver may try to decode the cellular user's message. The proposed scheme aims to optimize the achievable...
In this paper, we study the energy efficiency problem of the heterogeneous network composed of pico clusters deployed within the macro cells. We would like to find the optimal transmit power of the pico cells such that the energy efficiency of the cluster is the largest. A cell-specific cell selection bias is also considered so that each user may choose its serving cell in the most energy-efficient...
In this paper, we proposed a fundamental frequency prediction method which is used primarily in the voice conversion system. This paper establishes a Gaussian Mixture Model (GMM) to predict the fundamental frequency based on the Linear Predictive Cepstral Coefficient (LPCC). The model may be the speaker-dependent Gaussian mixture model or the speaker-independent universal background model that is...
The needs for location-aware applications are increasing with the popularity of ubiquitous mobile computing. However, as an important factor affecting the positioning performance, the deployment of anchor nodes has received little attention during the past years. In this paper we investigate the anchor placement in the received signal strength (RSS) based wireless localization systems. An optimization...
This paper presents a novel parallel breadth-first detection scheme for Multiple-Input Multiple-Output (MIMO) systems called Partial Inter-layer Parallel Sphere Decoder (PIPS-D). By introducing a new form of complex-to-real lattice transformation, the proposed algorithm can simultaneously compute every two adjacent layers of the equivalent search tree, thus significantly reducing the total execution...
In this paper, an optical camera communication system utilizing the under-sampled phase shift ON-OFF keying modulation is proposed to support non-flickering visible light communication. This system sends three types of light symbols through light emitting diode (LED) lamps, which are recorded by a camera. By employing a dual LED lamp with a designated mapping and framing method, the data rate can...
The homology groups provide useful information about a space. In several applications, including sensor networks, a combinatorial space is built to reflect the data and their relations about a specific topic to be analyzed. Hence the computation of the homology groups is of prime interest. However, the combinatorial space may vary and the computation of its homology groups becomes more difficult....
The classical preamble-based channel estimation for pulse shaping orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) systems requires zero-value guard symbols to guarantee interference avoidance, which leads to low spectral efficiency. In this study, we cut down the preamble structure without zero-value guard symbol to reduce preamble resource overhead. However, the intrinsic imaginary...
In this paper, a multi-slot spectrum sensing and transfer scheme inmultichannel CR is proposed by dividing the sensing stage into several time slots that are allocated to the subchannels for spectrum sensing. We formulate an optimization problem that maximizes the SU's aggregate throughput by jointly allocating the optimal number of sensing time slots and transfer power to each subchannel. The simulation...
Within the field of automated video analysis, detection of moving objects remains a challenging task due to the presence of dynamic background and camera motion. Dynamic scenes contain some moving objects such as trees jiggling slightly and water flowing irregularly. In this paper, we present an algorithm to address the problem of dynamic background, which employs spatio-temporal context and background...
In this paper, an improved K-best algorithm, which is suitable for low-complexity MIMO detector implementation is proposed. In order to balance the detector's bit-error-rate (BER) performance and computation complexity, several techniques, such as empirical path expansion and relaxed sorting have been proposed. Simulation results have shown that the proposed algorithm can achieve better computation...
Faced with the shortage of the radio resource in recent years, device-to-device (D2D) communication as an underlay to cellular networks has drawn much attention. Since D2D links will reuse the spectrum resources of cellular users, which will cause severe interference if not well controlled. In this paper we propose a spectrum allocation algorithm based on auction theory and a modified multi-auctioneer...
From the literature, we know that regular hexagonal coverage is the optimal seamless coverage for terrestrial wireless network, i.e. cellular network [1], as it could achieve minimum handover rates compared with other seamless coverage like triangle coverage, rectangle coverage and etc [2][3][4]. However, different from the terrestrial wireless network, both the movements of user equipments (UEs)...
Applying ray tracing method to radio propagation prediction in 3-D restricted spaces is challenging, not only because of the stringent requirement on precision, but also due to the explosive computation amount with tiny improvement in accuracy. In this paper, a unique algorithm for propagation prediction with transmission and reflection in restricted spaces is proposed. By using binary labels to record...
Software Defined Network (SDN) is undergoing an increasingly high popularity among various schemes of networking deployment. The main advantage of SDN lies in its flexibility in controlling network traffic, which arises from decoupling the control plane and the data plane of network devices. However, despite of the valuable merits of SDN, the outage of data forwarding should not be ignored. The drawback...
New reliable and accurate capacity bounds for Poisson channel modeled optical communication system are derived under peak-power and average-power constraints. The bounds are based on two entropy inequalities of Poisson random variables. Simulation results show that the proposed bounds are much tighter than previous ones, especially at lower signal-to-noise (SNR) region, where most wireless optical...
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