Heterogeneous networks(Het Nets)attracts a lot of attention due to its high capacity and large coverage for future communication networks.However,with the large-scale deployment of small cells,HetNets bears dramatical...Heterogeneous networks(Het Nets)attracts a lot of attention due to its high capacity and large coverage for future communication networks.However,with the large-scale deployment of small cells,HetNets bears dramatically increasing backhaul,which leads to a decrease of the outage performance.To improve the outage performance of Het Nets,we propose a wireless backhaul scheme for a two-layer HetNets,which automatically switches the three basic modes of orthogonal multiple access(OMA),nonorthogonal multiple access(NOMA)and cooperative non-orthogonal multiple access(CNOMA).First,we analyze the backhaul capacity and outage performance of these three basic modes.Then,we design the power allocation schemes based on minimizing outage probability for NOMA and CNOMA.Using the designed power allocation schemes,we propose a wireless backhaul scheme that switches the three modes according to the channel quality among different base stations(BSs).Moreover,the closed-form of the corresponding outage probability is derived.Compared with the three basic modes,the proposed wireless backhaul scheme can achieve the best outage performance and a higher backhaul capacity.Finally,all the analytical results are validated by simulations.展开更多
As next generation communication technologies emerge,new high data rate applications and high-definition large-screen video streaming have become very popular.As a result,network traffic has been increasing so much th...As next generation communication technologies emerge,new high data rate applications and high-definition large-screen video streaming have become very popular.As a result,network traffic has been increasing so much that existing backhaul networks soon will not be able to support all traffic demands.To support these needs in future 6G mobile systems,the establishment of an additional backhaul wireless network is considered essential.As one of the solutions,a wireless backhaul network based on an aerial platform has been proposed.In order to explore the potential of aerial platforms as wireless backhaul networks,in this paper,the categories for wireless backhaul networks based on aerial platforms are investigated.This paper includes a survey of the definitions and characteristics of low altitude platforms(LAPs)and high altitude platforms(HAPs),as well as channel models according to the atmosphere.For wireless backhaul network designs based on aerial platforms,altitude and platform selection options,deployment options,energy issues,and security based on target location and performance were considered in the analysis and investigation.展开更多
Ultra-dense networks （UDNs） are expected to be applied for the fifth generation wireless system （5G） to meet the requirements of very high throughput density and connections of a massive number of users. Consideri...Ultra-dense networks （UDNs） are expected to be applied for the fifth generation wireless system （5G） to meet the requirements of very high throughput density and connections of a massive number of users. Considering the large amount of small base stations （SBSs）, how to choose proper backhaul links is an important problem under investigation. In this paper, we propose a wireless backhaul algorithm to find an effective backhaul method for densely-deployed SBSs and to maximize energy efficiency of the system. We put forward adaptive backhaul methods of indirect and direct modes. The SBS can select the direct baekhaul which con- nects to the macro base station （MBS） directly, or the indirect backhaul which selects an idle SBS as a relay based on the backhaul channel condition. The algorithm also allocates network resources, including the power of SBSs and system bandwidth, to solve the serious interference problem in UDN. Finally, the simulation results show that the proposed wireless backhaul algorithm has desired performance to achieve higher energy efficiency with required data rate.展开更多
With the development of self-interference(SI) cancelation technology, full-duplex(FD) communication becomes possible. FD communication can theoretically double the spectral efficiency. When the time slot(TS) resources...With the development of self-interference(SI) cancelation technology, full-duplex(FD) communication becomes possible. FD communication can theoretically double the spectral efficiency. When the time slot(TS) resources are limited and the number of flows is large, the scheduling mechanism of the flows becomes more important. Therefore, the effectiveness of FD scheduling mechanism for the flows is studied in millimeter wave wireless backhaul network with the limited TS resources. We proposed a full duplex concurrent scheduling algorithm based on coalition game(FDCG) to maximize the number of flows with their QoS requirements satisfied. We transformed the problem of maximizing the number of flows with their QoS requirements satisfied into the problem of maximizing sum rate of concurrently scheduled flows in each slot. We obtained the scheduled flows with maximum sum rate in first slot by using coalition game.And then with certain restrictions, the maximum sum rate of concurrently scheduled flows can also be achieved in subsequent time slots. The simulation results show that the proposed FDCG algorithm canachieve superior performance in terms of the number of flows that meet their QoS requirements and system throughput compared with other three algorithms.展开更多
In this paper, we study the problem of resource allocation in small cell networks with distributed caching, that is, how to divide the spectrum resources for backhaul and access in order to improve network performance...In this paper, we study the problem of resource allocation in small cell networks with distributed caching, that is, how to divide the spectrum resources for backhaul and access in order to improve network performance. We formulate our concerned problem by using multi-dimensional Markov model. Our problem considers that each user may access multiple small cell base stations. We conduct simulation experiments to evaluate the performance of our proposed resource allocation scheme. Our simulation results show that the appropriate spectrum resource allocation is important to improve network performance.展开更多
Nowadays,video streaming applications are becoming one of the tendencies driving vehicular network users.In this work,considering the unpredictable vehicle density,the unexpected acceleration or deceleration of the di...Nowadays,video streaming applications are becoming one of the tendencies driving vehicular network users.In this work,considering the unpredictable vehicle density,the unexpected acceleration or deceleration of the different vehicles included in the vehicular traffic load,and the limited radio range of the employed communication scheme,we introduce the“Dynamic Vehicular Clustering”(DVC)algorithm as a new scheme for video streaming systems over vehicular ad-hoc networks(VANET).The proposed algorithm takes advantage of the small cells concept and the introduction of wireless backhauls,inspired by the different features and the performance of the Long Term Evolution(LTE)-Advanced network.Vehicles are clustered together to form dynamically ad-hoc sub-networks included in the vehicular network.The goal of our clustering algorithm is to take into account several characteristics,such as the vehicle’s position and acceleration to reduce latency and packet loss.Therefore,each cluster is counted as a small cell containing vehicular nodes and an access point that is elected regarding some particular specifications.Based on the exceptional features of the LTE-Advanced network(small cells and wireless backhauls)the DVC algorithm is a promising scheme for video streaming services over VANET systems.Experiments were carried out with a virtual topology of the VANET network created with four clusters to implement the DVC algorithm.The results were compared with other algorithms such as Virtual Trust-ability Data transmission(VTD),Named Data Networking(NDN),and Socially Aware Security Message Forwarding(SASMF).Our algorithm can effectively improve the transmission rate of data packets at the expense of a slight increase in end-to-end delay and control overhead.展开更多
基金supported in part by the National Science Foundation of China under Grant 61901185 and Grant 61971205。
文摘Heterogeneous networks(Het Nets)attracts a lot of attention due to its high capacity and large coverage for future communication networks.However,with the large-scale deployment of small cells,HetNets bears dramatically increasing backhaul,which leads to a decrease of the outage performance.To improve the outage performance of Het Nets,we propose a wireless backhaul scheme for a two-layer HetNets,which automatically switches the three basic modes of orthogonal multiple access(OMA),nonorthogonal multiple access(NOMA)and cooperative non-orthogonal multiple access(CNOMA).First,we analyze the backhaul capacity and outage performance of these three basic modes.Then,we design the power allocation schemes based on minimizing outage probability for NOMA and CNOMA.Using the designed power allocation schemes,we propose a wireless backhaul scheme that switches the three modes according to the channel quality among different base stations(BSs).Moreover,the closed-form of the corresponding outage probability is derived.Compared with the three basic modes,the proposed wireless backhaul scheme can achieve the best outage performance and a higher backhaul capacity.Finally,all the analytical results are validated by simulations.
基金This work was supported by Institute for Information&communications Technology Promotion(IITP)grant funded by the Korea government(MSIT)(No.2019-0-00685Free space optical communication based vertical mobile network).
文摘As next generation communication technologies emerge,new high data rate applications and high-definition large-screen video streaming have become very popular.As a result,network traffic has been increasing so much that existing backhaul networks soon will not be able to support all traffic demands.To support these needs in future 6G mobile systems,the establishment of an additional backhaul wireless network is considered essential.As one of the solutions,a wireless backhaul network based on an aerial platform has been proposed.In order to explore the potential of aerial platforms as wireless backhaul networks,in this paper,the categories for wireless backhaul networks based on aerial platforms are investigated.This paper includes a survey of the definitions and characteristics of low altitude platforms(LAPs)and high altitude platforms(HAPs),as well as channel models according to the atmosphere.For wireless backhaul network designs based on aerial platforms,altitude and platform selection options,deployment options,energy issues,and security based on target location and performance were considered in the analysis and investigation.
基金jointly supported by the National Natural Science Foundation of China under Grant Nos.61771070 and 61671088the National Science and Technology Major Project under Grant No.2016ZX03001017
文摘Ultra-dense networks （UDNs） are expected to be applied for the fifth generation wireless system （5G） to meet the requirements of very high throughput density and connections of a massive number of users. Considering the large amount of small base stations （SBSs）, how to choose proper backhaul links is an important problem under investigation. In this paper, we propose a wireless backhaul algorithm to find an effective backhaul method for densely-deployed SBSs and to maximize energy efficiency of the system. We put forward adaptive backhaul methods of indirect and direct modes. The SBS can select the direct baekhaul which con- nects to the macro base station （MBS） directly, or the indirect backhaul which selects an idle SBS as a relay based on the backhaul channel condition. The algorithm also allocates network resources, including the power of SBSs and system bandwidth, to solve the serious interference problem in UDN. Finally, the simulation results show that the proposed wireless backhaul algorithm has desired performance to achieve higher energy efficiency with required data rate.
基金supported by the National Natural Science Foundation of China Grants 61725101 and 61801016the China Postdoctoral Science Foundation under Grant 2017M610040 and 2018T110041+2 种基金National key research and development program under Grant 2016YFE0200900the Beijing Natural Fund under Grant L172020Major projects of Beijing Municipal Science and Technology Commission under Grant No. Z181100003218010
文摘With the development of self-interference(SI) cancelation technology, full-duplex(FD) communication becomes possible. FD communication can theoretically double the spectral efficiency. When the time slot(TS) resources are limited and the number of flows is large, the scheduling mechanism of the flows becomes more important. Therefore, the effectiveness of FD scheduling mechanism for the flows is studied in millimeter wave wireless backhaul network with the limited TS resources. We proposed a full duplex concurrent scheduling algorithm based on coalition game(FDCG) to maximize the number of flows with their QoS requirements satisfied. We transformed the problem of maximizing the number of flows with their QoS requirements satisfied into the problem of maximizing sum rate of concurrently scheduled flows in each slot. We obtained the scheduled flows with maximum sum rate in first slot by using coalition game.And then with certain restrictions, the maximum sum rate of concurrently scheduled flows can also be achieved in subsequent time slots. The simulation results show that the proposed FDCG algorithm canachieve superior performance in terms of the number of flows that meet their QoS requirements and system throughput compared with other three algorithms.
基金supported in part by the National Natural Science Foundation of China (Grants Nos. 61571351, and 61401326)the important national science & technology specific projects 2015ZX03002006-003Natural Science Basic Research Plan in Shaanxi Province of China (Program Nos. 2016JM6028 and 2016JQ6054)
文摘In this paper, we study the problem of resource allocation in small cell networks with distributed caching, that is, how to divide the spectrum resources for backhaul and access in order to improve network performance. We formulate our concerned problem by using multi-dimensional Markov model. Our problem considers that each user may access multiple small cell base stations. We conduct simulation experiments to evaluate the performance of our proposed resource allocation scheme. Our simulation results show that the appropriate spectrum resource allocation is important to improve network performance.
文摘Nowadays,video streaming applications are becoming one of the tendencies driving vehicular network users.In this work,considering the unpredictable vehicle density,the unexpected acceleration or deceleration of the different vehicles included in the vehicular traffic load,and the limited radio range of the employed communication scheme,we introduce the“Dynamic Vehicular Clustering”(DVC)algorithm as a new scheme for video streaming systems over vehicular ad-hoc networks(VANET).The proposed algorithm takes advantage of the small cells concept and the introduction of wireless backhauls,inspired by the different features and the performance of the Long Term Evolution(LTE)-Advanced network.Vehicles are clustered together to form dynamically ad-hoc sub-networks included in the vehicular network.The goal of our clustering algorithm is to take into account several characteristics,such as the vehicle’s position and acceleration to reduce latency and packet loss.Therefore,each cluster is counted as a small cell containing vehicular nodes and an access point that is elected regarding some particular specifications.Based on the exceptional features of the LTE-Advanced network(small cells and wireless backhauls)the DVC algorithm is a promising scheme for video streaming services over VANET systems.Experiments were carried out with a virtual topology of the VANET network created with four clusters to implement the DVC algorithm.The results were compared with other algorithms such as Virtual Trust-ability Data transmission(VTD),Named Data Networking(NDN),and Socially Aware Security Message Forwarding(SASMF).Our algorithm can effectively improve the transmission rate of data packets at the expense of a slight increase in end-to-end delay and control overhead.
