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With the fast development of high-speed trains (HST) globally, some related technical issues of HST communications should be addressed, e.g. time- variant (TV) radio channel modeling and channel estimation. In this paper, we propose a more generic TV channel model based on Qian Liu's research. Moreover, a generalized subspace-based channel estimation algorithm with the aid of an improved basic expansion...
Fractional Frequency Reuse (FFR) has been adopted in current two-tier Heterogeneous Networks (HetNet) with femtocells deployed in the presence of an overlaid macrocell. This technology would effectively reduce the inter-cell interference (ICI), from both co-tier and cross-tier, and thus achieve higher system throughput. Cell partitioning is an important parameter in FFR scheme. In this article, a...
With the growing concern over energy consumption, green communication is becoming more and more important. Lots of efforts have been put into investigating in energy-efficient wireless systems. Since Fractional Frequency Reuse (FFR) is a widely-used Inter-cell-interference coordination scheme in the OFDMA wireless network, we consider the energy-efficient power control in the FFR system. With demanded...
Finite impulse response (FIR) precoders are efficient precoding framework for frequency-selective multiple-input multiple-output (MIMO) channels. In this paper, the optimal linear FIR precoder is investigated to maximize the capacity of frequency-selective MIMO channel under average transmit power constraint. We use Kronecker product to regenerate the nonconvex optimization problem and propose a semidefinite...
In this paper, we study the subchannel (SC) power allocation for orthogonal frequency division multiplexing (OFDM) multiple access points (APs) systems with non-coherent cooperative transmission. The objective is to maximize the total capacity under per-AP power constraints. It can be proved that the optimal solution can be obtained by the combination of an optimal SC partition search and the power...
In this letter, we investigate the energy efficiency in the generalized distributed antenna systems (GDAS) with the frequency-selective fading. An energy efficient power allocation (EE-PA) problem, minimizing the Joule consumed per bit under per antenna power constraint, is formulated as a nonlinear fractional programming (FP) problem. Optimality conditions for the FP problem are first introduced...
The two-tier femtocell network is comprised of a central macrocell underlaid with shorter range femtocell hotspots. Due to the universal frequency reuse, this kind of new system architecture brings about urgent problems of the interference management and the resource allocation. Motivated by these problems, the following contributions are made in this paper: 1) a novel joint power and subchannel allocation...
In this paper, we consider a static cluster of base stations where joint processing is allowed in the downlink. The partial joint processing scheme is a user-centric approach where subclusters or active sets of base stations are dynamically defined for each user in the cluster. In frequency selective channels, the definition of the subclusters or active set thresholding of base stations can be frequency...
In order to control the interference, and improve the spectral efficiency in the Femtocell and Macrocell Overlaid System (FMOS), the FMOS model is built and Combination of Frequency bandwidth dynamic division and Clustering Algorithm (CFCA) is proposed for Orthogonal Frequency Division Multiple Access (OFDMA) FMOS. In CFCA, the optimal clustering problem in terms of interference mitigation is constructed...
Coordinated Multi-Point (CoMP) transmission is considered in 3GPP LTE-Advanced as a key technique to improve the cell-edge performance. In order to support joint resource allocation among coordinate cells in CoMP systems, efficient frequency reuse schemes need to be designed. However, most of the existing frequency reuse schemes are not suitable for CoMP transmission due to not considering multi-cell...
The problem of resource allocation in multiuser OFDM system is a combinatorial optimization problem, difficult to solve in polynomial time. For the sake of reducing complexity, it can be solved either by relaxing constraints and making use of linear algorithms or by metaheuristic methods. In this paper, ant colony optimization, a typical algorithm of metaheuristic methods, is applied to solve the...
This paper presents Customer Satisfaction (CS) based resource allocation strategy in orthogonal frequency-division multiplexing (OFDM) wireless system with multimedia traffic. The risk aversion utility functions are analyzed, based on which, the CS utility and the CS resource allocation strategy are proposed. Compared with the Proportional Fairness (PF) utility, the CS utility enables the system to...
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