This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary d...This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary demand and substitution probability of each cell phone card based on historical sales data. This estimation model is nonlinear, so we transform it to a mixed integer linear programming model by logarithmic transformations and piecewise＇linear approximation. On the basis of the estimation results, we can make assortment planning. Considering the resource of cell phone cards is limited, we jointly optimize the assortment and quantity planning of cell phone cards. In numerical study, we apply our approach to a large mobile service provider in China and frod our approach can increase the revenue of this mobile service provider by 23.69%. Sensitivity analysis shows the mobile service provider should provide more assortments to increase revenue when the types of cell phone cards that can be assigned to each store are limited.展开更多
Recently, unmanned aerial vehicles （UAVs） acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifi...Recently, unmanned aerial vehicles （UAVs） acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifically, in the scenario where the access point （AP） is mobile, a UAV needs to find an efficient path to guarantee the connectivity of the relay link. Motivated by this fact, this paper proposes an optimal design for beamforming （BF） and UAV path planning. First of all, we study a dual-hop amplify-and-forward （AF） wireless relay network, in which a UAV is used as relay between a mobile AP and a fixed base station （BS）. In the network, both of the AP and the BS are equipped with multiple antennas, whereas the UAV has a single antenna. Then, we obtain the output signal^to-noise ratio （SNR） of the dual-hop relay network. Based on the criterion of maximizing the output SNR, we develop an optimal design to obtain the solution of the optimal BF weight vector and the UAV heading angle. Next, we derive the closed-form outage probability （OP） expression to investigate the performance of the dual-hop relay network conveniently. Finally, computer simulations show that the proposed approach can obtain nearly optimal flying path and OP performance, indicating the effectiveness of the proposed algorithm. Furthermore, we find that increasing the antenna number at the BS or the maximal heading angle can significantly improve the performance of the considered relay network.展开更多
Due to its inherent characteristics of flexible mobility,unmanned aerial vehicle(UAV) is exploited as a cost-efficient mobile platform to assist remote data collection in the 5 th generation or beyond the 5 th generat...Due to its inherent characteristics of flexible mobility,unmanned aerial vehicle(UAV) is exploited as a cost-efficient mobile platform to assist remote data collection in the 5 th generation or beyond the 5 th generation(5 G/B5 G) wireless systems.Compared with static terrestrial base stations,the line-of-sight(LoS) link between UAVs and ground nodes are stronger due to their flexibility in three-dimensional(3 D) space.Due to the fact that flexible mobility of UAVs requires high propulsion power,the limited on-board energy constrains the performance of UAV-assisted data collection.It is worth noting that UAVs can be categorized into rotary-wing UAVs and fixed-wing UAVs,either has its own characteristics in propulsion energy consumption.In this article,a comprehensive review of state-of-art studies on trajectory design schemes for rotary-wing UAVs,as well as aerodynamic-aware attitude control strategies for fixed-wing UAVs was provided.Then,two case studies for energy-efficient data collection using rotary-wing UAVs and fixed-wing UAVs were presented,respectively.More specifically,an age-energy aware data collection scheme was demonstrated for rotary-wing UAVs to optimize the timeliness of collected data.Moreover,an aerodynamic-aware attitude control strategy for fixed-wing UAVs was also demonstrated under data collection requirements.展开更多
基金This research was partially supported by the National Science Foundation of China [Grants 71401086, 71332005 and 71361130017].
文摘This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary demand and substitution probability of each cell phone card based on historical sales data. This estimation model is nonlinear, so we transform it to a mixed integer linear programming model by logarithmic transformations and piecewise＇linear approximation. On the basis of the estimation results, we can make assortment planning. Considering the resource of cell phone cards is limited, we jointly optimize the assortment and quantity planning of cell phone cards. In numerical study, we apply our approach to a large mobile service provider in China and frod our approach can increase the revenue of this mobile service provider by 23.69%. Sensitivity analysis shows the mobile service provider should provide more assortments to increase revenue when the types of cell phone cards that can be assigned to each store are limited.
基金supported by the National Natural Science Foundation of China (Nos. 61202351, 61271255)the Natural Science Foundation of Jiangsu Province (No. BK20131068)+2 种基金the Open Research Fund of National Mobile Communications Research Laboratory in Southeast University (No. 2012D15)the Funding of Jiangsu Innovation Program for Graduate Education (No. CXLX11_0202)the Fundamental Research Funds for the Central Universities
文摘Recently, unmanned aerial vehicles （UAVs） acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifically, in the scenario where the access point （AP） is mobile, a UAV needs to find an efficient path to guarantee the connectivity of the relay link. Motivated by this fact, this paper proposes an optimal design for beamforming （BF） and UAV path planning. First of all, we study a dual-hop amplify-and-forward （AF） wireless relay network, in which a UAV is used as relay between a mobile AP and a fixed base station （BS）. In the network, both of the AP and the BS are equipped with multiple antennas, whereas the UAV has a single antenna. Then, we obtain the output signal^to-noise ratio （SNR） of the dual-hop relay network. Based on the criterion of maximizing the output SNR, we develop an optimal design to obtain the solution of the optimal BF weight vector and the UAV heading angle. Next, we derive the closed-form outage probability （OP） expression to investigate the performance of the dual-hop relay network conveniently. Finally, computer simulations show that the proposed approach can obtain nearly optimal flying path and OP performance, indicating the effectiveness of the proposed algorithm. Furthermore, we find that increasing the antenna number at the BS or the maximal heading angle can significantly improve the performance of the considered relay network.
基金supported by the National Science Foundation for Young Scientists of China Project (61801045)the Beijing Natural Science Foundation (L192033)。
文摘Due to its inherent characteristics of flexible mobility,unmanned aerial vehicle(UAV) is exploited as a cost-efficient mobile platform to assist remote data collection in the 5 th generation or beyond the 5 th generation(5 G/B5 G) wireless systems.Compared with static terrestrial base stations,the line-of-sight(LoS) link between UAVs and ground nodes are stronger due to their flexibility in three-dimensional(3 D) space.Due to the fact that flexible mobility of UAVs requires high propulsion power,the limited on-board energy constrains the performance of UAV-assisted data collection.It is worth noting that UAVs can be categorized into rotary-wing UAVs and fixed-wing UAVs,either has its own characteristics in propulsion energy consumption.In this article,a comprehensive review of state-of-art studies on trajectory design schemes for rotary-wing UAVs,as well as aerodynamic-aware attitude control strategies for fixed-wing UAVs was provided.Then,two case studies for energy-efficient data collection using rotary-wing UAVs and fixed-wing UAVs were presented,respectively.More specifically,an age-energy aware data collection scheme was demonstrated for rotary-wing UAVs to optimize the timeliness of collected data.Moreover,an aerodynamic-aware attitude control strategy for fixed-wing UAVs was also demonstrated under data collection requirements.
