![]() Tran Dinh, Hieu ![]() ![]() ![]() Scientific Conference (2019, November 03) This paper studies a new energy-efficient unmanned aerial vehicle (UAV)-enabled wireless communications, where the UAV acts as a flying base station (BS) to serve the ground users (GUs) within some ... [more ▼] This paper studies a new energy-efficient unmanned aerial vehicle (UAV)-enabled wireless communications, where the UAV acts as a flying base station (BS) to serve the ground users (GUs) within some predetermined latency limitations, e.g., requested timeout (RT). Our goal is to design the UAV trajectory to minimize the total energy consumption while satisfying the RT requirement from every GU, which is accomplished via two consecutive subproblems: traveling time minimization and energy minimization problems. Firstly, we propose two exhaustive search and heuristic algorithms based on the traveling salesman problem with time window (TSPTW) in order to minimize the UAV’s traveling time without violating the GUs’ RT requirements. While the exhaustive algorithm achieves the best performance at a high computation cost, the heuristic algorithm achieves a trade-off between the performance and complexity. Secondly, we minimize the total energy consumption, for a given trajectory, via a joint optimization of the UAV’s velocity along subsequent hops. Finally, numerical results are presented to demonstrate the effectiveness of our proposed algorithms. In particular, it is shown that the proposed solutions outperform the reference in terms of both energy consumption and outage performance. [less ▲] Detailed reference viewed: 74 (6 UL)![]() ; Vu, Thang Xuan ![]() ![]() in IEEE European Signal Processing Conference 2019 (2019, September) Detailed reference viewed: 68 (19 UL)![]() Lei, Lei ![]() in IEEE Transactions on Green Communications and Networking (2019) Detailed reference viewed: 79 (9 UL)![]() Lei, Lei ![]() ![]() ![]() in IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC 2019) (2019, September) Detailed reference viewed: 78 (11 UL)![]() Lei, Lei ![]() ![]() ![]() in IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) 2019 (2019, July) Detailed reference viewed: 69 (25 UL)![]() Vu, Thang Xuan ![]() ![]() ![]() in IEEE Communications Letters (2019) Detailed reference viewed: 59 (6 UL)![]() Vu, Thang Xuan ![]() ![]() ![]() in 2019 IEEE International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt) (2019, June) Detailed reference viewed: 71 (15 UL)![]() Gautam, Sumit ![]() ![]() ![]() in Duong, Trung; Chu, Xiaoli; Suraweera, Himal (Eds.) Ultra-Dense Networks for 5G and Beyond - Modelling, Analysis, and Applications (2019) In this chapter, we investigate the performance of a time-switching (TS) based energy harvesting model for cache-assisted simultaneous wireless transmission of information and energy (Wi-TIE). In the ... [more ▼] In this chapter, we investigate the performance of a time-switching (TS) based energy harvesting model for cache-assisted simultaneous wireless transmission of information and energy (Wi-TIE). In the considered system, a relay which is equipped with both caching and energy harvesting capabilities helps a source to convey information to a destination. Based on the time-splitting mechanism, we analyze the effect of caching on the system performance in terms of stored energy at the relay and the relay-destination link throughput. In particular, two optimization problems are formulated to maximize the energy stored at the relay and the relay-destination throughput. By using KKT method, closed-form solution are obtained for both the problems. Finally, the performance of the proposed design under various operating conditions and parameter values is illustrated using numerical results. [less ▲] Detailed reference viewed: 146 (33 UL)![]() Vu, Thang Xuan ![]() ![]() in 2019 IEEE Wireless Communications and Networking Conference (WCNC) (2019) Detailed reference viewed: 43 (4 UL)![]() Vu, Thang Xuan ![]() ![]() ![]() in 2019 IEEE International Conference on Recent Advances in Signal Processing, Telecommunications & Computing (SigTelCom) (2019) Detailed reference viewed: 38 (6 UL)![]() Vu, Thang Xuan ![]() ![]() Scientific Conference (2018, October) The fifth generation (5G) wireless networks have to deal with the high data rate and stringent latency requirements due to the massive invasion of connected devices and data-hungry applications. Edge ... [more ▼] The fifth generation (5G) wireless networks have to deal with the high data rate and stringent latency requirements due to the massive invasion of connected devices and data-hungry applications. Edge caching is a promising technique to overcome these challenges by prefetching the content closer to the end users at the edge node's local storage. In this paper, we analyze the performance of edge caching 5G networks with the aid of satellite communication systems. Firstly, we investigate the satellite-aided edge caching systems in two promising use cases: a) in dense urban areas, and b) in sparsely populated regions, e.g., rural areas. Secondly, we study the effectiveness of satellite systems via the proposed satellite-aided caching algorithm, which can be used in three configurations: i) mono-beam satellite, ii) multi-beam satellite, and iii) hybrid mode. Thirdly, the proposed caching algorithm is evaluated by using both empirical Zipf-distribution data and the more realistic Movielens dataset. [less ▲] Detailed reference viewed: 132 (9 UL)![]() Lei, Lei ![]() ![]() in 2018 IEEE International Conference on Communications (ICC) (2018, July) Detailed reference viewed: 123 (29 UL)![]() Vu, Thang Xuan ![]() ![]() ![]() in IEEE Wireless Communications Letters (2018), 7(3), 332-335 Content caching is an efficient technique to reduce delivery latency and system congestion during peak-traffic time by bringing data closer to end users. In this letter, we investigate energy-efficiency ... [more ▼] Content caching is an efficient technique to reduce delivery latency and system congestion during peak-traffic time by bringing data closer to end users. In this letter, we investigate energy-efficiency performance of cache-assisted content delivery networks with wireless backhaul by taking into account cache capability when designing the signal transmission. We consider multi-layer caching and the performance in cases when both base station and users are capable of storing content data in their local cache. Specifically, we analyze energy consumption in both backhaul and access links under two uncoded and coded caching strategies. Then two optimization problems are formulated to minimize total energy cost for the two caching strategies while satisfying some given quality of service constraint. We demonstrate via numerical results that the uncoded caching achieves higher energy efficiency than the coded caching in the small user cache size regime. [less ▲] Detailed reference viewed: 67 (2 UL)![]() Vu, Thang Xuan ![]() ![]() in 2018 IEEE International Conference on Communications (ICC) (2018, May) Detailed reference viewed: 113 (15 UL)![]() Vu, Thang Xuan ![]() ![]() in 2018 IEEE Wireless Communications and Networking Conference (WCNC) (2018, May) Detailed reference viewed: 121 (19 UL)![]() Gautam, Sumit ![]() ![]() ![]() Scientific Conference (2018, April 16) We investigate the performance of time switching (TS) based energy harvesting model for cache-assisted simultaneous wireless transmission of information and energy (Wi-TIE). In the considered system, a ... [more ▼] We investigate the performance of time switching (TS) based energy harvesting model for cache-assisted simultaneous wireless transmission of information and energy (Wi-TIE). In the considered system, a relay which is equipped with both caching and energy harvesting capabilities helps a source to convey information to a destination. First, we formulate based on the time-switching architecture an optimization problem to maximize the harvested energy, taking into consideration the cache capability and user quality of service requirement. We then solve the formulated problem to obtain closed-form solutions. Finally, we demonstrate the effectiveness of the proposed system via numerical results. [less ▲] Detailed reference viewed: 195 (29 UL)![]() Vuppala, Satyanarayana ![]() ![]() ![]() Scientific Conference (2018, April 16) In this paper, we investigate the performance of cache enabled millimeter wave (mmWave) ad-hoc network, where randomly distributed nodes are supported by a cache memory. Specifically, we study the optimal ... [more ▼] In this paper, we investigate the performance of cache enabled millimeter wave (mmWave) ad-hoc network, where randomly distributed nodes are supported by a cache memory. Specifically, we study the optimal caching placement at the desirable mmWave node using a network model that accounts for the uncertainties in node locations and blockages. We then characterize the average success probability of content delivery. As a desirable side effect, certain factors like the density of nodes and increased antenna gain, can significantly increase the cache hit ratio in mmWave networks. However, a trade-off between the cache hit probability and the average successful content delivery probability with respect to the density of nodes is presented. [less ▲] Detailed reference viewed: 165 (23 UL)![]() Vuppala, Satyanarayana ![]() ![]() ![]() in IEEE Transactions on Communications (2018) The narrow-beam operation in millimeter wave (mmWave) networks minimizes the network interference leading to a noise-limited networks in contrast with interference-limited ones. The medium access control ... [more ▼] The narrow-beam operation in millimeter wave (mmWave) networks minimizes the network interference leading to a noise-limited networks in contrast with interference-limited ones. The medium access control (MAC) layer throughput, and interference management strategies heavily depend on the noise-limited or interference-limited regime. Yet, these regimes are not considered in recent mmWave MAC layer designs, which can potentially have disastrous consequences on the communication performance. In this paper, we investigate the performance of cache-enabled MAC based mmWave ad-hoc networks, where randomly distributed nodes are supported by a cache. The adhoc nodes are modeled as homogenous Poisson Point Processes (PPP). Specifically, we study the optimal content placement (or caching placement) at desirable mmWave nodes using a network model that accounts for uncertainties both in node locations and blockages. We propose a contention-based multimedia delivery protocol to avoid collisions among the concurrent transmissions. Subsequently, only the node with smallest back-off timer amongst its contenders is allowed to transmit. We then characterize the average success probability of content delivery. We also characterize the cache hit ratio probability, and transmission probability of this system under essential factors, such as blockages, node density, path loss and caching parameters. [less ▲] Detailed reference viewed: 187 (40 UL)![]() Vu, Thang Xuan ![]() ![]() ![]() in IEEE Transactions on Wireless Communications (2018) Edge-caching has received much attention as an efficient technique to reduce delivery latency and network congestion during peak-traffic times by bringing data closer to end users. Existing works usually ... [more ▼] Edge-caching has received much attention as an efficient technique to reduce delivery latency and network congestion during peak-traffic times by bringing data closer to end users. Existing works usually design caching algorithms separately from physical layer design. In this paper, we analyse edge-caching wireless networks by taking into account the caching capability when designing the signal transmission. Particularly, we investigate multi-layer caching where both base station (BS) and users are capable of storing content data in their local cache and analyse the performance of edge-caching wireless networks under two notable uncoded and coded caching strategies. Firstly, we calculate backhaul and access throughputs of the two caching strategies for arbitrary values of cache size. The required backhaul and access throughputs are derived as a function of the BS and user cache sizes. Secondly, closed-form expressions for the system energy efficiency (EE) corresponding to the two caching methods are derived. Based on the derived formulas, the system EE is maximized via precoding vectors design and optimization while satisfying a predefined user request rate. Thirdly, two optimization problems are proposed to minimize the content delivery time for the two caching strategies. Finally, numerical results are presented to verify the effectiveness of the two caching methods. [less ▲] Detailed reference viewed: 183 (13 UL)![]() Gautam, Sumit ![]() ![]() ![]() in IEEE Journal on Selected Areas In Communications (2018) In this paper, we investigate the performance of cache-assisted simultaneous wireless information and power transfer (SWIPT) cooperative systems, in which one source communicates with one destination via ... [more ▼] In this paper, we investigate the performance of cache-assisted simultaneous wireless information and power transfer (SWIPT) cooperative systems, in which one source communicates with one destination via the aid of multiple relays. In order to prolong the relays’ serving time, the relays are assumed to be equipped with a cache memory and energy harvesting (EH) capability. Based on the time-splitting mechanism, we analyze the effect of caching on the system performance in terms of the serving throughput and the stored energy at the relay. In particular, two optimization problems are formulated to maximize the relay-destination throughput and the energy stored at the relay subject to some quality-of-service (QoS) constraints, respectively. By using the KKT conditions and with the help of the Lambert function, closed-form solutions are obtained for the two formulated problems. In order to further improve the performance, a relay selection policy is introduced to select the best relay based on either the maximum throughput between the relays’ and destination link or maximum stored energy at the relay, for conveying information to the destination. Numerical results reveal significant benefits of incorporating caching capabilities to SWIPT systems, in terms of improved serving time, throughput and energy harvesting performance at the relays. [less ▲] Detailed reference viewed: 233 (31 UL) |
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