Lusheng Wang

Cooperative Scheduling for Coexisting Body Area Networks

Body area networks (BANs), referring to embedded wireless systems in, on, and around bodies, are expected to take an important role for health, leisure, sports, and all the facets of our daily life. In many cases, several BANs coexist in a small area, resulting in very strong inter-BAN interference, which seriously disturbs intra-BAN communications. The goal of this paper is to decrease inter-BAN interference by cooperative scheduling, hence increasing packet reception rate (PRR) of intra-BAN communications. Cooperative scheduling here is divided into two sub-problems: single-BAN scheduling as an assignment problem and multi-BAN concurrent scheduling as a game. For the first sub-problem, a low complexity algorithm, horse racing scheduling, is proposed, which achieves near-optimal PRR for the BAN performing scheduling. For the second sub-problem, we prove the existence of a set of mixed strategy Nash equilibria (MSNE). Then, we propose a distributed cooperative scheduling scheme, which efficiently achieves higher PRR than the MSNE without degrading fairness.

OpenAirInterface Traffic Generator (OTG): A Realistic Traffic Generation Tool for Emerging Application Scenarios

Traffic generation represents one of the main challenge in modeling and simulating the application and network load. In this work, we present a tool, called OpenAirInterface Traffic Generator (OTG), for the generation of realistic application traffic that can be used for testing and evaluating the performance of emerging networking architectures. In addition to the traffic of conventional applications, OTG is capable of accurately emulating the traffic of new application scenarios such as online gaming and machine-type communication. To highlight the capability and new features of the tool, the one-way delay of OpenArena online gaming application in the presence of the background traffic is analyzed over the LTE network using OpenAirInterface emulation platform.

Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things.

With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified.

An Analytical Framework for Multilayer Partial Frequency Reuse Scheme Design in Mobile Communication Systems

Partial frequency reuse (PFR) is one of the key techniques to improving max-min fairness for cell-edge user equipment in the fourth generation of mobile communication systems. Recently, multilayer PFR schemes have been proposed, which are considered to be a promising evolution of this technique. In this paper, we propose an analytical framework for multilayer PFR scheme design, which uses a triplet to completely describe a given PFR scheme. Then, closed-form expressions of the average spatial capacities of certain typical regions of a cell are derived. Based on a comprehensive analysis using this framework, a novel multilayer PFR scheme is designed, which divides each cell into inner, middle, and outer layers, with two homolographic sublayers for the middle layer. Reuse factors for the three layers are 1, 3/2, and 3, respectively, and an orthogonal division of the spectrum among different layers is guaranteed. Based on our numerical results, this novel scheme outperforms the traditional two-layer PFR scheme in max-min fairness without degrading the average spatial capacity. Compared with several representative multilayer PFR schemes, it achieves a better tradeoff between these two metrics.

Efficient resource allocation and interference management using compressive sensing in dense mobile communication systems

In dense mobile communication systems, time efficiency is a vital demand for resource allocation (RA), as well as inter-cell interference coordination (ICIC), due to the fact that the scale of RA optimization is extremely large. Existing optimization schemes, such as Hungarian algorithm, are too time-consuming to reach an optimal solution, which does not fit for RA in dense scenarios. In this paper, we employ the compressive sensing (CS) technique to design a CS-based scheme, which uses wavelet transform, Hadamard matrix, and CoSaMP algorithm for sparse representation, measurement, and reconstruction, respectively. Simulation results show the sparsity, the feasibility, and the gain of time efficiency by using the CS technique. We can see that, in dense system, our proposal could achieve a near-optimal RA solution with significantly decreased time cost. Meanwhile, in 2-cell scenario, the interference can also be coordinated effectively by the CS-based RA scheme.

Practical framework for ultra-fair dynamic interference coordination in mobile communication systems

Inter-cell interference coordination (ICIC) has been widely studied in recent years, in which dynamic schemes form one of the most promising categories thanks to their flexibility and high performance. By carefully coordinating user equipments (UEs) in adjacent cells using Hungarian algorithm or heuristic algorithms, inter-cell interference can be decreased and traditional max–min fairness can be achieved. However, some interferers are so strong that even UEs close to their evolved nodeBs can be damaged to low performance, referred to as ‘excessive coordination’ in this study. Therefore, the authors propose a framework for ultra-fair dynamic ICIC, which balances the serious impacts of strong interferers so that higher max–min fairness than the traditional one can be achieved. By dividing the coordination procedure into periods, the authors’ framework maintains a utility matrix obtained by combining the instantaneous channel state information of the current period and previously achieved cumulative spectral efficiencies. Heuristic algorithms are used on this utility matrix periodically to achieve higher max–min fairness. In this way, a fairer coordination than traditional max–min fairness is achieved after iterating for several periods. Extensive simulations demonstrate that their framework largely improves max–min fairness without obviously degrading the system spectral efficiency.

Performance evaluation of dynamic interference coordination algorithms

Dynamic interference coordination has been widely studied and the core coordination algorithm is the keypoint to determine its performance. However, there lacks a complete performance evaluation of existing coordination algorithms in the literature. This paper focuses on average utility, fairness, and time complexity of various algorithms in homogeneous and heterogeneous 2-cell scenarios. We find that greedy and alternated horse racing achieve both high utility and fairness. Alternated inverse quick pairing reaches high utility and fairness when inter-cell interference (ICI) is not serious. Alternated quick pairing, alternated inverse quick pairing, and alternated horse racing out-perform others in terms of time complexity. To sum up, we conclude that, for the case with serious ICI, alternated horse racing should be promising, while for the case when ICI is not quite serious, alternated inverse quick pairing becomes probably the best choice.