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SGCO: Stabilized Green Crosshaul Orchestration for Dense IoT Offloading Services
Dao, Nhu-Ngoc,Vu, Duc-Nghia,Na, Woongsoo,Kim, Joongheon,Cho, Sungrae IEEE 2018 IEEE journal on selected areas in communications Vol.36 No.11
<P>The next-generation mobile network anticipates integrated heterogeneous fronthaul and backhaul technologies referred to as a unified crosshaul architecture. The crosshaul enables a flexible and cost-efficient infrastructure for handling mobile data tsunami from dense Internet of things (IoT). However, stabilization, energy efficiency, and latency have not been jointly considered in the optimization of crosshaul performance. To overcome these issues, we propose an orchestration scheme referred to as the stabilized green crosshaul orchestration (SGCO). SGCO utilizes a Lyapunov-theory-based drift-plus-penalty policy to determine the optimal amount of offloaded data that should be processed either at the eastbound or westbound computing platforms to minimize energy consumption. To achieve system stability, the cache buffer is considered as the main constraint in developing the optimization process. Moreover, the amount of offloaded data transmitted via crosshaul links is selected by adopting the binary min-knapsack problem. Accordingly, a lightweight heuristic algorithm is proposed. As the cache buffer is stabilized and the computations are controlled, the SGCO ensures adjustable computing latency threshold for various IoT services. The performance analysis shows that the proposed SGCO scheme exposes effective energy consumption compared to other existing schemes while maintaining system stability considering latency.</P>
Na, Woongsoo,Dao, Nhu-Ngoc,Kim, Joongheon,Ryu, Eun-Seok,Cho, Sungrae Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.2
Numerous wearable technology companies have recently developed several headmounted display (HMD) products for virtual reality (VR) services. 5G wireless networks aim at providing high-quality 3D multimedia services such as VR, augmented reality, and mixed reality. In this study, we examine the application of millimeter-wave (mmWave) technology to realize low-latency wireless communication between an HMD and its content server. However, the propagation characteristics of mmWave present several challenges such as the deafness, blockage, and beam alignment problems, and interference among content servers. In this study, we focus on an environment that provides VR services in the mmWave band and introduce existing techniques for addressing such challenges. In addition, we employ a commercialized IEEE 802.11ad VR dongle to measure the actual data rate of an mmWave VR application and identify the degree to which the performance deteriorates when the above problems occur. Finally, we verify the feasibility of the proposed solutions through a simulation of several VR scenarios in the mmWave band.
Directional Link Scheduling for Real-Time Data Processing in Smart Manufacturing System
Na, Woongsoo,Lee, Yunseong,Dao, Nhu-Ngoc,Vu, Duc Nghia,Masood, Arooj,Cho, Sungrae IEEE 2018 IEEE Internet of things journal Vol.5 No.5
<P>Internet of Things (IoT) technology has accelerated various industries through digital transformation. In an edge computing-based smart factory, a significant number of IoT devices generate large volumes of real-time data. This big data requires efficient routing among edge gateways (EGs) and an edge server for real-time data processing. Existing industrial wireless communication systems provide relatively low data rates and network capacity for real-time sensor data and control information over a wireless channel. This calls for the use of the very large bandwidth available at the mmWave spectrum for real-time data transmission. Existing data routing techniques for the mmWave band are based on traditional mobile ad hoc routing techniques and do not reduce the transmission delay for real-time sensory data in smart manufacturing systems. Therefore, to alleviate the real-time data processing requirement, we propose a new directional routing and link scheduling algorithm based on maximum weight independent set (MWIS). The proposed algorithm solves complicated MWIS problems efficiently and computes backhaul link scheduling results in a relatively short time by lowering the deafness problem among EGs. For transmission fairness, we used a Jain’s fairness index method with numerical analysis of the transmission fairness constraint. We measured the efficiency of our proposed scheme in terms of throughput, delay, packet loss rate, and transmission fairness. Our simulation results show that the proposed scheme outperforms existing mmWave routing techniques. Moreover, we investigated the performance difference between the proposed algorithm and the optimal solution.</P>
On sum-rate maximization in downlink UAV-aided RSMA systems
Hua Duc-Thien,Do Quang Tuan,Dao Nhu-Ngoc,Cho Sungrae 한국통신학회 2024 ICT Express Vol.10 No.1
The synergy of uncrewed aerial vehicles (UAVs) and the rate-splitting multiple access (RSMA) technique has thrived as a crucial enabler for multi-user broadband sixth-generation networks. This paper investigates a UAV-aided RSMA downlink communication system considering user mobility and the uniform rectangular array antenna design. In particular, the sum-rate maximization problem is formulated where the UAV beamforming matrix, common rate allocation, and UAV trajectory design are jointly optimized. The deep deterministic policy gradient (DDPG) approach has been proposed to address the nonconcave objective function. In addition, the safe action shaping technique is incorporated into the algorithm to satisfy the variable constraints of the problem statement. The numerical simulation results demonstrated that the proposed approach outperformed other benchmark schemes in various settings of transmit powers and fading environment levels.