Energy-efficient Trajectory Design for UAV-enabled Wireless Communications with Latency Constraints

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 ▲]

Learning-Assisted Optimization for Energy-Efficient Scheduling in Deadline-Aware NOMA Systems

in IEEE Transactions on Green Communications and Networking (2019)

Learning-Based Resource Allocation: Efficient Content Delivery Enabled by Convolutional Neural Network

in IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) 2019 (2019, July)

Machine Learning based Antenna Selection and Power Allocation in Multi-user MISO Systems

in 2019 IEEE International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt) (2019, June)

Linear Precoding Design for Cache-aided Full-duplex Networks

in 2019 IEEE Wireless Communications and Networking Conference (WCNC) (2019)

Efficient 5G Edge Caching Over Satellite

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 ▲]

Energy Minimization for Cache-Assisted Content Delivery Networks With Wireless Backhaul

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 ▲]

Energy-efficient design for latency-tolerant content delivery networks

in 2018 IEEE Wireless Communications and Networking Conference (WCNC) (2018, May)

Cache-Aided Millimeter Wave Ad-Hoc Networks

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 ▲]

Edge-Caching Wireless Networks: Performance Analysis and Optimization

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 ▲]