Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322461
Anirudh Agarwal, Deepak Mishra
Advent of unmanned aerial vehicle (UAV) as relay in ad-hoc networks has offered numerous promising communication solutions with both military and civilian applications. Additionally with more degrees of freedom, mobile UAV relaying provides better susceptibility to changing environment conditions thereby enhancing the network performance. However, optimization of UAV altitude is a primary concern in such flying ad hoc networks (FANETs). In this work, we consider a three node decode-and-forward (DF) FANET, and the aim is to minimize the average network outage probability subject to practical mobility constraints of maximum UAV velocity and minimum allowable UAV height, thereby finally optimizing the overall UAV trajectory (UT). In particular, for pre-determined initial and final relay positions, we first prove convexity of the optimization problem and then obtain the semi-closed-form globally optimal UT solution. The analysis is numerically validated along with the discussion of multiple optimal design insights. Results reveal the respective average performance gain of 56% and 37% over the two benchmark schemes.
{"title":"Altitude Optimization for DF Relaying Trajectory of UAV in Cooperative FANET","authors":"Anirudh Agarwal, Deepak Mishra","doi":"10.1109/GLOBECOM42002.2020.9322461","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322461","url":null,"abstract":"Advent of unmanned aerial vehicle (UAV) as relay in ad-hoc networks has offered numerous promising communication solutions with both military and civilian applications. Additionally with more degrees of freedom, mobile UAV relaying provides better susceptibility to changing environment conditions thereby enhancing the network performance. However, optimization of UAV altitude is a primary concern in such flying ad hoc networks (FANETs). In this work, we consider a three node decode-and-forward (DF) FANET, and the aim is to minimize the average network outage probability subject to practical mobility constraints of maximum UAV velocity and minimum allowable UAV height, thereby finally optimizing the overall UAV trajectory (UT). In particular, for pre-determined initial and final relay positions, we first prove convexity of the optimization problem and then obtain the semi-closed-form globally optimal UT solution. The analysis is numerically validated along with the discussion of multiple optimal design insights. Results reveal the respective average performance gain of 56% and 37% over the two benchmark schemes.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"60 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73551090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322455
K. S. Khan, Noman Haider, A. Jamalipour
Optimal content caching has been an important topic in dense small cell networks. Due to spatial and temporal variation in the popularity of data, most content requests cannot be directly served by the lower tiers of the network, increasing the chances of congestion at the core network. This raises the issues of what to cache and where to cache, especially for content with different popularity patterns in a given region. In this work, we focus on the issue of redundant caching of popular files in a cluster when designing a content allocation scheme. We formulate the considered problem as a stable matching theory problem, where the preferences of each cache entity are sent to the Macro Base Station (MBS) for stable matching. The caches share their request lists with the MBS, which subsequently uses Irving One-Sided matching algorithm to generate a unique preference list for each caching entity such that every preference list is a representative of the popular data in that region. The algorithm achieves the desired goal of efficient caching with few but smartly planned repetitions of the popular files. Results show that our proposed scheme provides better performance in terms of cache hit ratio with increasing number of requests as compared to a popularity based scheme.
{"title":"Content Caching and Allocation in Spatially Correlated Small Cells","authors":"K. S. Khan, Noman Haider, A. Jamalipour","doi":"10.1109/GLOBECOM42002.2020.9322455","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322455","url":null,"abstract":"Optimal content caching has been an important topic in dense small cell networks. Due to spatial and temporal variation in the popularity of data, most content requests cannot be directly served by the lower tiers of the network, increasing the chances of congestion at the core network. This raises the issues of what to cache and where to cache, especially for content with different popularity patterns in a given region. In this work, we focus on the issue of redundant caching of popular files in a cluster when designing a content allocation scheme. We formulate the considered problem as a stable matching theory problem, where the preferences of each cache entity are sent to the Macro Base Station (MBS) for stable matching. The caches share their request lists with the MBS, which subsequently uses Irving One-Sided matching algorithm to generate a unique preference list for each caching entity such that every preference list is a representative of the popular data in that region. The algorithm achieves the desired goal of efficient caching with few but smartly planned repetitions of the popular files. Results show that our proposed scheme provides better performance in terms of cache hit ratio with increasing number of requests as compared to a popularity based scheme.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"45 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73806740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322341
M. Guenach, A. Gorji, A. Bourdoux
One of the major bottlenecks that hinders the deployment of Cell-free (CF) massive Multiple-Input MultipleOutput (MIMO) in a cost-effective way is the limited capacity of back/front-haul connections. In this case, the traffic between the large number of distributed access points (APs) and the central processing unit can easily explode. Expensive pointto-point fronthauling technologies are certainly not desirable hence a shared fronthaul medium should be foreseen wherein (a subset of) APs share the same bandwidth-limited medium. However, the point-to-multipoint architectures require proper AP scheduling. In this paper, we propose a novel unified optimization framework for iterative power control and AP scheduling in the uplink of the cell-free massive MIMO system, that offers a systematic user-centric solution towards scalable CF massive MIMO. The experimental results show that power control is not sufficient to reach the best minimum throughput and, therefore, an appropriate association of the users to the APs is crucial to improve the overall system performance.
{"title":"Iterative Power Allocation and Access Point Scheduling in Uplink Cell-Free Massive MIMO Systems","authors":"M. Guenach, A. Gorji, A. Bourdoux","doi":"10.1109/GLOBECOM42002.2020.9322341","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322341","url":null,"abstract":"One of the major bottlenecks that hinders the deployment of Cell-free (CF) massive Multiple-Input MultipleOutput (MIMO) in a cost-effective way is the limited capacity of back/front-haul connections. In this case, the traffic between the large number of distributed access points (APs) and the central processing unit can easily explode. Expensive pointto-point fronthauling technologies are certainly not desirable hence a shared fronthaul medium should be foreseen wherein (a subset of) APs share the same bandwidth-limited medium. However, the point-to-multipoint architectures require proper AP scheduling. In this paper, we propose a novel unified optimization framework for iterative power control and AP scheduling in the uplink of the cell-free massive MIMO system, that offers a systematic user-centric solution towards scalable CF massive MIMO. The experimental results show that power control is not sufficient to reach the best minimum throughput and, therefore, an appropriate association of the users to the APs is crucial to improve the overall system performance.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"33 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75507963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9347984
Laura Flueratoru, S. Wehrli, M. Magno, D. Niculescu
Ultra-wideband (UWB) communication is attracting increased interest for its high-accuracy distance measurements. However, the typical current consumption of tens to hundreds of mA during transmission and reception might make the technology prohibitive to battery-powered devices in the Internet of Things. The IEEE 802.15.4 standard specifies two UWB physical layer interfaces (PHYs), with low- and high-rate pulse repetition (LRP and HRP, respectively). While the LRP PHY allows a more energy-efficient implementation of the UWB transceiver than its HRP counterpart, the question is whether some ranging quality is lost in exchange. We evaluate the trade-off between power and energy consumption, on the one hand, and distance measurement accuracy and precision, on the other hand, using UWB devices developed by Decawave (HRP) and 3db Access (LRP). We find that the distance measurement errors of 3db Access devices have at most 12 cm higher bias and standard deviation in line-of-sight propagation and 2–3 times higher spread in non-line-of-sight scenarios than those of Decawave devices. However, 3db Access chips consume 10 times less power and 125 times less energy per distance measurement than Decawave ones. Since the LRP PHY has an ultra-low energy consumption, it should be preferred over the HRP PHY when energy efficiency is critical, with a small penalty in the ranging performance.
{"title":"On the Energy Consumption and Ranging Accuracy of Ultra-Wideband Physical Interfaces","authors":"Laura Flueratoru, S. Wehrli, M. Magno, D. Niculescu","doi":"10.1109/GLOBECOM42002.2020.9347984","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9347984","url":null,"abstract":"Ultra-wideband (UWB) communication is attracting increased interest for its high-accuracy distance measurements. However, the typical current consumption of tens to hundreds of mA during transmission and reception might make the technology prohibitive to battery-powered devices in the Internet of Things. The IEEE 802.15.4 standard specifies two UWB physical layer interfaces (PHYs), with low- and high-rate pulse repetition (LRP and HRP, respectively). While the LRP PHY allows a more energy-efficient implementation of the UWB transceiver than its HRP counterpart, the question is whether some ranging quality is lost in exchange. We evaluate the trade-off between power and energy consumption, on the one hand, and distance measurement accuracy and precision, on the other hand, using UWB devices developed by Decawave (HRP) and 3db Access (LRP). We find that the distance measurement errors of 3db Access devices have at most 12 cm higher bias and standard deviation in line-of-sight propagation and 2–3 times higher spread in non-line-of-sight scenarios than those of Decawave devices. However, 3db Access chips consume 10 times less power and 125 times less energy per distance measurement than Decawave ones. Since the LRP PHY has an ultra-low energy consumption, it should be preferred over the HRP PHY when energy efficiency is critical, with a small penalty in the ranging performance.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"29 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74423351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9347973
I. Martín-Escalona, E. Zola
Indoor positioning is still considered an open issue, especially when general-purpose communication networks are used to observe the metrics for positioning. IEEE 802.11mc aims at providing positioning capabilities to Wi-Fi networks. Google recently developed a feature aimed at making easy to run the standard in any Android device; however, only few access points (APs) officially support and advertise it. It is proven, though, that a bunch of APs are able to attend the location requests from 802.11mc devices despite not announcing their positioning capabilities. An application is proposed here that effectively gathers a list of all the APs that may collaborate in the indoor positioning process. This work is aimed at studying the performance of the location error in a real scenario where Android Wi-Fi devices run the IEEE 802.11mc positioning facility. The results demonstrate that, although errors are smaller than 2 meters as promised, the performance greatly depends on the AP and the frequency band used.
{"title":"Ranging Estimation Error in WiFi Devices Running IEEE 802.11mc","authors":"I. Martín-Escalona, E. Zola","doi":"10.1109/GLOBECOM42002.2020.9347973","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9347973","url":null,"abstract":"Indoor positioning is still considered an open issue, especially when general-purpose communication networks are used to observe the metrics for positioning. IEEE 802.11mc aims at providing positioning capabilities to Wi-Fi networks. Google recently developed a feature aimed at making easy to run the standard in any Android device; however, only few access points (APs) officially support and advertise it. It is proven, though, that a bunch of APs are able to attend the location requests from 802.11mc devices despite not announcing their positioning capabilities. An application is proposed here that effectively gathers a list of all the APs that may collaborate in the indoor positioning process. This work is aimed at studying the performance of the location error in a real scenario where Android Wi-Fi devices run the IEEE 802.11mc positioning facility. The results demonstrate that, although errors are smaller than 2 meters as promised, the performance greatly depends on the AP and the frequency band used.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"30 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74589108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322547
Siyuan Yu, Yawei Lu, W. Chen
Remote reconstruction of trajectories of dynamical systems is now emerging as a mission-critical application in Industry 4.0 and beyond. Unfortunately, the statistical properties of signals generated by dynamical systems usually remain unknown, which prohibits the use of classic source coding methods relying on a statistical source model. To overcome this difficulty, we present a paradigm shift data transmission scheme, assuring that the reconstruction error is limited with the aid of the computation unit. It is found that the bit rate for transmitting trajectories has a significant relationship with the predictability of dynamical systems. Together with the concept of the Lyapunov exponent, an error growth function is introduced in this paper to classify the dynamical systems according to their predictability. A general expression of the bit rate is obtained in this paper. Furthermore, it is shown that the asymptotic value of the bit rate to reconstruct trajectories of a chaotic system is given by its Lyapunov exponent. The bit rate to reconstruct trajectories of non-chaotic systems is also presented. Simulation results show that our scheme outperforms conventional information-theory-based coding schemes, and can significantly reduce bandwidth requirements.
{"title":"Computation-Aided Data Transmission for Remote Reconstruction of Trajectories of Dynamical Systems","authors":"Siyuan Yu, Yawei Lu, W. Chen","doi":"10.1109/GLOBECOM42002.2020.9322547","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322547","url":null,"abstract":"Remote reconstruction of trajectories of dynamical systems is now emerging as a mission-critical application in Industry 4.0 and beyond. Unfortunately, the statistical properties of signals generated by dynamical systems usually remain unknown, which prohibits the use of classic source coding methods relying on a statistical source model. To overcome this difficulty, we present a paradigm shift data transmission scheme, assuring that the reconstruction error is limited with the aid of the computation unit. It is found that the bit rate for transmitting trajectories has a significant relationship with the predictability of dynamical systems. Together with the concept of the Lyapunov exponent, an error growth function is introduced in this paper to classify the dynamical systems according to their predictability. A general expression of the bit rate is obtained in this paper. Furthermore, it is shown that the asymptotic value of the bit rate to reconstruct trajectories of a chaotic system is given by its Lyapunov exponent. The bit rate to reconstruct trajectories of non-chaotic systems is also presented. Simulation results show that our scheme outperforms conventional information-theory-based coding schemes, and can significantly reduce bandwidth requirements.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"254 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73213086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322218
M. Tayyab, G. Koudouridis, X. Gelabert, R. Jäntti
In today’s cellular networks, an increasing number of connected devices on-board in fast-moving vehicles would require more efficient handover (HO) procedures. To this end, we investigate the utilization of mobile relay nodes (MRNs) in vehicles to facilitate efficient HO and HO-related power consumption reductions for all on-board user equipments (UEs). In particular, the potential gains in terms of HO rate, HO failure ratio (HOFR), ping-pong (PP) rate, and total power consumption are studied for different UE cluster sizes. To eliminate the measurement power-consuming procedure, uplink (UL) reference signals (RS) transmitted by UEs are exploited. Four different case scenarios are simulated utilizing both the DL and UL RS based HO procedure, with and without deploying MRNs on the buses traveling along the cell edges of surrounding macro BSs. Simulation results indicate that the UL RS based HO procedure can improve HO performance significantly because it reduces the air-interface signaling messages, namely the measurement report (MeasReport) transmission and reception. Also, in terms of power consumption, deploying MRNs is a more attractive solution with substantial power reduction for onboard UEs of higher cluster size.
{"title":"Uplink Reference Signal Based Handover with Mobile Relay Node Assisted User Clustering","authors":"M. Tayyab, G. Koudouridis, X. Gelabert, R. Jäntti","doi":"10.1109/GLOBECOM42002.2020.9322218","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322218","url":null,"abstract":"In today’s cellular networks, an increasing number of connected devices on-board in fast-moving vehicles would require more efficient handover (HO) procedures. To this end, we investigate the utilization of mobile relay nodes (MRNs) in vehicles to facilitate efficient HO and HO-related power consumption reductions for all on-board user equipments (UEs). In particular, the potential gains in terms of HO rate, HO failure ratio (HOFR), ping-pong (PP) rate, and total power consumption are studied for different UE cluster sizes. To eliminate the measurement power-consuming procedure, uplink (UL) reference signals (RS) transmitted by UEs are exploited. Four different case scenarios are simulated utilizing both the DL and UL RS based HO procedure, with and without deploying MRNs on the buses traveling along the cell edges of surrounding macro BSs. Simulation results indicate that the UL RS based HO procedure can improve HO performance significantly because it reduces the air-interface signaling messages, namely the measurement report (MeasReport) transmission and reception. Also, in terms of power consumption, deploying MRNs is a more attractive solution with substantial power reduction for onboard UEs of higher cluster size.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"217 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74175302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9348016
Caihong Kai, Wenqi Ding, W. Huang
The potential application of intelligent reflecting surfaces (IRSs) for future wireless cellular communication systems has motivated the study of metasurface for achieving additional space degree of freedom, where IRS is used to enhance the desired signal strength and suppress the interference. In this paper, by using the additional design degree of freedom provided by the IRS, we jointly optimize the transmit beamforming vector at the BS and the reflective beamforming vector at the IRS to maximize the minimum rate in the IRS-aided multi-user multiple-input-single-output broadcast channel (MISO-BC), subject to the unit modulus constraints of the reflective beamforming vector. In order to solve the non-convex optimization problem, we propose an efficient algorithm based on alternating optimization. In particular, we optimize the transmit beamforming vectors via the second-order cone problem (SOCP) and reflective beamforming vector by using the semi-definite relaxation (SDR). Numerical results show that the use of IRS leads to significant higher SINR values than benchmark schemes without IRS.
{"title":"Max-Min Fairness in IRS-Aided MISO Broadcast Channel via Joint Transmit and Reflective Beamforming","authors":"Caihong Kai, Wenqi Ding, W. Huang","doi":"10.1109/GLOBECOM42002.2020.9348016","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9348016","url":null,"abstract":"The potential application of intelligent reflecting surfaces (IRSs) for future wireless cellular communication systems has motivated the study of metasurface for achieving additional space degree of freedom, where IRS is used to enhance the desired signal strength and suppress the interference. In this paper, by using the additional design degree of freedom provided by the IRS, we jointly optimize the transmit beamforming vector at the BS and the reflective beamforming vector at the IRS to maximize the minimum rate in the IRS-aided multi-user multiple-input-single-output broadcast channel (MISO-BC), subject to the unit modulus constraints of the reflective beamforming vector. In order to solve the non-convex optimization problem, we propose an efficient algorithm based on alternating optimization. In particular, we optimize the transmit beamforming vectors via the second-order cone problem (SOCP) and reflective beamforming vector by using the semi-definite relaxation (SDR). Numerical results show that the use of IRS leads to significant higher SINR values than benchmark schemes without IRS.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"213 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74354603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322537
Ziyan He, Liang Wang, Hao Ye, Geoffrey Y. Li, B. Juang
In this article, we investigate spectrum allocation in vehicle-to-everything (V2X) network. We first express the V2X network into a graph, where each vehicle-to-vehicle (V2V) link is a node in the graph. We apply a graph neural network (GNN) to learn the low-dimensional feature of each node based on the graph information. According to the learned feature, multi-agent reinforcement learning (RL) is used to make spectrum allocation. Deep Q-network is utilized to learn to optimize the sum capacity of the V2X network. Simulation results show that the proposed allocation scheme can achieve near-optimal performance.
{"title":"Resource Allocation based on Graph Neural Networks in Vehicular Communications","authors":"Ziyan He, Liang Wang, Hao Ye, Geoffrey Y. Li, B. Juang","doi":"10.1109/GLOBECOM42002.2020.9322537","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322537","url":null,"abstract":"In this article, we investigate spectrum allocation in vehicle-to-everything (V2X) network. We first express the V2X network into a graph, where each vehicle-to-vehicle (V2V) link is a node in the graph. We apply a graph neural network (GNN) to learn the low-dimensional feature of each node based on the graph information. According to the learned feature, multi-agent reinforcement learning (RL) is used to make spectrum allocation. Deep Q-network is utilized to learn to optimize the sum capacity of the V2X network. Simulation results show that the proposed allocation scheme can achieve near-optimal performance.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"11 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74357511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.1109/GLOBECOM42002.2020.9322428
Wenjin Wang, Tingting Chen, Rui Ding, G. Seco-Granados, Li You, Xiqi Gao
Integrated satellite-terrestrial communications networks aim to exploit both the satellite and the ground mobile communications and thus provide genuine ubiquitous coverage. For 5G integrated low earth orbit (LEO) satellite communication (SatCom) systems, the timing advance (TA) is required to be estimated in the initial random access procedure of communications in order to facilitate the uplink frame alignment among different users. However, due to the inherent characteristics of LEO SatCom systems, the existing 5G terrestrial uplink TA scheme is not applicable in the satellite networks. In this paper, we investigate location-based TA estimation for 5G integrated LEO SatCom systems. We propose to take the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements obtained in the downlink timing and frequency synchronization phase for geographical location estimation, which are made from the satellite at different time instants. The location estimation is then formulated as a quadratic optimization problem. We propose an approximation method based on iteratively performing a linearization procedure on the quadratic equality constraints to solve this problem. Numerical results show that the proposed method can effectively assure uplink frame alignment among different users in typical LEO SatCom systems.
{"title":"Location-Based Timing Advance Estimation for 5G Integrated LEO Satellite Communications","authors":"Wenjin Wang, Tingting Chen, Rui Ding, G. Seco-Granados, Li You, Xiqi Gao","doi":"10.1109/GLOBECOM42002.2020.9322428","DOIUrl":"https://doi.org/10.1109/GLOBECOM42002.2020.9322428","url":null,"abstract":"Integrated satellite-terrestrial communications networks aim to exploit both the satellite and the ground mobile communications and thus provide genuine ubiquitous coverage. For 5G integrated low earth orbit (LEO) satellite communication (SatCom) systems, the timing advance (TA) is required to be estimated in the initial random access procedure of communications in order to facilitate the uplink frame alignment among different users. However, due to the inherent characteristics of LEO SatCom systems, the existing 5G terrestrial uplink TA scheme is not applicable in the satellite networks. In this paper, we investigate location-based TA estimation for 5G integrated LEO SatCom systems. We propose to take the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements obtained in the downlink timing and frequency synchronization phase for geographical location estimation, which are made from the satellite at different time instants. The location estimation is then formulated as a quadratic optimization problem. We propose an approximation method based on iteratively performing a linearization procedure on the quadratic equality constraints to solve this problem. Numerical results show that the proposed method can effectively assure uplink frame alignment among different users in typical LEO SatCom systems.","PeriodicalId":12759,"journal":{"name":"GLOBECOM 2020 - 2020 IEEE Global Communications Conference","volume":"7 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72711049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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