The Experts below are selected from a list of 156129 Experts worldwide ranked by ideXlab platform
Jeffrey G Andrews - One of the best experts on this subject based on the ideXlab platform.
-
an analytical framework for modeling a spatially repulsive Cellular Network
IEEE Transactions on Communications, 2018Co-Authors: Changsik Choi, Jae Oh Woo, Jeffrey G AndrewsAbstract:We propose a new Cellular Network model that captures both deterministic and random aspects of base station (BS) deployments. Namely, the BS locations are modeled as the superposition of two independent stationary point processes: a random shifted grid with intensity $ \lambda _{g} $ and a Poisson point process (PPP) with intensity $ \lambda _{p} $ . Grid and PPP deployments are special cases with $\lambda _{p} \to 0$ and $\lambda _{g} \to 0$ , with actual deployments in between these two extremes, as we demonstrate with deployment data. Assuming that each user is associated with the BS that provides the strongest average received signal power, we obtain the probability that a typical user is associated with either a grid or PPP BS. Assuming Rayleigh fading channels, we derive the expression for the coverage probability of the typical user, resulting in the following observations. First, the association and the coverage probability of the typical user are fully characterized as functions of intensity ratio $ \rho _\lambda =\lambda _{p}/\lambda _{g}$ . Second, the user association is biased toward the BSs located on a grid. Finally, the proposed model predicts the coverage probability of the actual deployment with great accuracy.
-
an analytical framework for modeling a spatially repulsive Cellular Network
arXiv: Information Theory, 2017Co-Authors: Changsik Choi, Jae Oh Woo, Jeffrey G AndrewsAbstract:We propose a new Cellular Network model that captures both deterministic and random aspects of base station deployments. Namely, the base station locations are modeled as the superposition of two independent stationary point processes: a random shifted grid with intensity $\lambda_g$ and a Poisson point process (PPP) with intensity $\lambda_p$. Grid and PPP deployments are special cases with $\lambda_p \to 0$ and $\lambda_g \to 0$, with actual deployments in between these two extremes, as we demonstrate with deployment data. Assuming that each user is associated with the base station that provides the strongest average received signal power, we obtain the probability that a typical user is associated with either a grid or PPP base station. Assuming Rayleigh fading channels, we derive the expression for the coverage probability of the typical user, resulting in the following observations. First, the association and the coverage probability of the typical user are fully characterized as functions of intensity ratio $\rho_\lambda = \lambda_p/\lambda_g$. Second, the user association is biased towards the base stations located on a grid. Finally, the proposed model predicts the coverage probability of the actual deployment with great accuracy.
-
a primer on Cellular Network analysis using stochastic geometry
arXiv: Information Theory, 2016Co-Authors: Jeffrey G Andrews, Abhishek K Gupta, Harpreet S. DhillonAbstract:This tutorial is intended as an accessible but rigorous first reference for someone interested in learning how to model and analyze Cellular Network performance using stochastic geometry. In particular, we focus on computing the signal-to-interference-plus-noise ratio (SINR) distribution, which can be characterized by the coverage probability (the SINR CCDF) or the outage probability (its CDF). We model base stations (BSs) in the Network as a realization of a homogeneous Poisson point process of density $\lambda$, and compute the SINR for three main cases: the downlink, uplink, and finally the multi-tier downlink, which is characterized by having $k$ tiers of BSs each with a unique density $\lambda_i$ and transmit power $p_i$. These three baseline results have been extensively extended to many different scenarios, and we conclude with a brief summary of some of those extensions.
-
Downlink Cellular Network analysis with a dual-slope path loss model
2015 IEEE International Conference on Communications (ICC), 2015Co-Authors: Xinchen Zhang, Jeffrey G AndrewsAbstract:Existing Cellular Network analyses are based on the standard power law path loss model. If the base stations are modeled by a Poisson point process, this leads to a tractable analysis of coverage probability and other metrics for downlink Cellular Networks. Yet, it is also well-known that the standard path loss model is idealized and does not capture the distance-dependence of the path loss exponent. This paper considers a more precise and general model, the dual-slope path loss model, where the path loss exponents are different for short links and long links differentiated by a critical distance. We derive compact expressions on the coverage probability and its tight closed-form estimate under this model. The analytical results show that the SINR does not monotonically increase with Network density (as under the standard path loss model). Rather, ultra-densification leads to worse or even zero coverage when the near-field path loss exponent is 2 or less.
-
Downlink Cellular Network Analysis With Multi-Slope Path Loss Models
IEEE Transactions on Communications, 2015Co-Authors: Xinchen Zhang, Jeffrey G AndrewsAbstract:Existing Cellular Network analyses, and even simulations, typically use the standard path loss model where received power decays like $\Vert x\Vert^{-\alpha}$ over a distance $\Vert x\Vert$ . This standard path loss model is quite idealized, and in most scenarios the path loss exponent $\alpha$ is itself a function of $\Vert x\Vert$ , typically an increasing one. Enforcing a single path loss exponent can lead to orders of magnitude differences in average received and interference powers versus the true values. In this paper, we study multi-slope path loss models, where different distance ranges are subject to different path loss exponents. We focus on the dual-slope path loss function, which is a piece-wise power law and continuous and accurately approximates many practical scenarios. We derive the distributions of SIR, SNR, and finally SINR before finding the potential throughput scaling, which provides insight on the observed cell-splitting rate gain. The exact mathematical results show that the SIR monotonically decreases with Network density, while the converse is true for SNR, and thus the Network coverage probability in terms of SINR is maximized at some finite density. With ultra-densification (Network density goes to infinity), there exists a phase transition in the near-field path loss exponent $\alpha_{0}$ : if $\alpha_{0} >1$ unbounded potential throughput can be achieved asymptotically; if $\alpha_{0} , ultra-densification leads in the extreme case to zero throughput.
Huan Zhou - One of the best experts on this subject based on the ideXlab platform.
-
v2v data offloading for Cellular Network based on the software defined Network sdn inside mobile edge computing mec architecture
IEEE Access, 2018Co-Authors: Chung-ming Huang, Duy-tuan Dao, Meng-shu Chiang, Huan ZhouAbstract:Data offloading plays an important role for the mobile data explosion problem that occurs in Cellular Networks. This paper proposed an idea and control scheme for offloading vehicular communication traffic in the Cellular Network to vehicle to vehicle (V2V) paths that can exist in vehicular ad hoc Networks (VANETs). A software-defined Network (SDN) inside the mobile edge computing (MEC) architecture, which is abbreviated as the SDNi-MEC server, is devised in this paper to tackle the complicated issues of VANET V2V offloading. Using the proposed SDNi-MEC architecture, each vehicle reports its contextual information to the context database of the SDNi-MEC server, and the SDN controller of the SDNi-MEC server calculates whether there is a V2V path between the two vehicles that are currently communicating with each other through the Cellular Network. This proposed method: 1) uses each vehicle’s context; 2) adopts a centralized management strategy for calculation and notification; and 3) tries to establish a VANET routing path for paired vehicles that are currently communicating with each other using a Cellular Network. The performance analysis for the proposed offloading control scheme based on the SDNi-MEC server architecture shows that it has better throughput in both the Cellular Networking link and the V2V paths when the vehicle’s density is in the middle.
-
Vehicle-to-Infrastructure (V2I) offloading from Cellular Network to 802.11p Wi-Fi Network based on the Software-Defined Network (SDN) architecture
Vehicular Communications, 2017Co-Authors: Chung-ming Huang, Hsiu Ming Pai, Duy-tuan Dao, Meng-shu Chiang, Shouzhi Xu, Huan ZhouAbstract:This paper proposes a prediction control scheme called Offloading with Handover Decision based on Software-Defined Network (OHD–SDN) for the offloading of the vehicle-to-infrastructure communication using the Software-Defined Network (SDN) Architecture. In the proposed control scheme, when the vehicle with an On Board Unit (OBU), which has a Cellular Network interface and an IEEE 802.11p Network interface, connects to Cellular Network, the SDN Controller monitors it to make decision about the offloading indication based on the reported information, including speed, geographical position, direction, and sensed neighboring RSUs' IDs, from the vehicle. The SDN Controller calculates when the due time is to make decision, decides whether it is suitable or not to have the vehicle to handoff from Cellular Network to the ahead IEEE 802.11p Network of a RSU, and then notifies the vehicle to stay in Cellular Network if the Networking situation of the ahead RSUs IEEE 802.11p Network is not suitable or to switch from Cellular Network to the ahead RSUs IEEE 802.11p Network if the Networking situation of the ahead RSU's IEEE 802.11p Network is suitable. The simulation results show that the Cellular Networks load and traffic can be reduced and the Networking quality of the vehicle being in the IEEE 802.11p Network of a RSU can be assured using the proposed OHD–SDN control scheme.
-
802.11p Wi-Fi Offloading from the Cellular Network to Vehicle-to-Infrastructure Communication Network Using the Software-Defined Network (SDN) Technique
Internet of Vehicles – Technologies and Services, 2016Co-Authors: Chung-ming Huang, Hsiu Ming Pai, Duy-tuan Dao, Meng-shu Chiang, Shouzhi Xu, Huan ZhouAbstract:Wi-Fi offloading is a technique for reducing 3G/3.5G/4G Cellular Network’s traffic load and users’ expense spent in 3G/3.5G/4G Cellular Network. Nevertheless, it needs to judge whether the offloading from the Cellular Network to the Wi-Fi Network is valuable or not by considering the target Wi-Fi Network’s situation. This paper proposed a Software Defined Network (SDN) –based method to pre-decide whether it is valuable to have offloading from the Cellular Network to the corresponding vehicle’s ahead 802.11p Wi-Fi RSU Network or not. By utilizing the centralization architecture and the information of the current contexts, including speed, position and direction, of vehicles, SDN Controller can calculate whether the Networking situation of the corresponding vehicle’s ahead 802.11p Wi-Fi RSU is good enough to offload or not before the vehicle enters into the signal coverage. The performance analysis shows that it can let vehicles have better Networking situation and quality using our proposed scheme.
Xinchen Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Downlink Cellular Network analysis with a dual-slope path loss model
2015 IEEE International Conference on Communications (ICC), 2015Co-Authors: Xinchen Zhang, Jeffrey G AndrewsAbstract:Existing Cellular Network analyses are based on the standard power law path loss model. If the base stations are modeled by a Poisson point process, this leads to a tractable analysis of coverage probability and other metrics for downlink Cellular Networks. Yet, it is also well-known that the standard path loss model is idealized and does not capture the distance-dependence of the path loss exponent. This paper considers a more precise and general model, the dual-slope path loss model, where the path loss exponents are different for short links and long links differentiated by a critical distance. We derive compact expressions on the coverage probability and its tight closed-form estimate under this model. The analytical results show that the SINR does not monotonically increase with Network density (as under the standard path loss model). Rather, ultra-densification leads to worse or even zero coverage when the near-field path loss exponent is 2 or less.
-
Downlink Cellular Network Analysis With Multi-Slope Path Loss Models
IEEE Transactions on Communications, 2015Co-Authors: Xinchen Zhang, Jeffrey G AndrewsAbstract:Existing Cellular Network analyses, and even simulations, typically use the standard path loss model where received power decays like $\Vert x\Vert^{-\alpha}$ over a distance $\Vert x\Vert$ . This standard path loss model is quite idealized, and in most scenarios the path loss exponent $\alpha$ is itself a function of $\Vert x\Vert$ , typically an increasing one. Enforcing a single path loss exponent can lead to orders of magnitude differences in average received and interference powers versus the true values. In this paper, we study multi-slope path loss models, where different distance ranges are subject to different path loss exponents. We focus on the dual-slope path loss function, which is a piece-wise power law and continuous and accurately approximates many practical scenarios. We derive the distributions of SIR, SNR, and finally SINR before finding the potential throughput scaling, which provides insight on the observed cell-splitting rate gain. The exact mathematical results show that the SIR monotonically decreases with Network density, while the converse is true for SNR, and thus the Network coverage probability in terms of SINR is maximized at some finite density. With ultra-densification (Network density goes to infinity), there exists a phase transition in the near-field path loss exponent $\alpha_{0}$ : if $\alpha_{0} >1$ unbounded potential throughput can be achieved asymptotically; if $\alpha_{0} , ultra-densification leads in the extreme case to zero throughput.
-
downlink Cellular Network analysis with multi slope path loss models
arXiv: Information Theory, 2014Co-Authors: Xinchen Zhang, Jeffrey G AndrewsAbstract:Existing Cellular Network analyses, and even simulations, typically use the standard path loss model where received power decays like $\|x\|^{-\alpha}$ over a distance $\|x\|$. This standard path loss model is quite idealized, and in most scenarios the path loss exponent $\alpha$ is itself a function of $\|x\|$, typically an increasing one. Enforcing a single path loss exponent can lead to orders of magnitude differences in average received and interference powers versus the true values. In this paper we study \emph{multi-slope} path loss models, where different distance ranges are subject to different path loss exponents. We focus on the dual-slope path loss function, which is a piece-wise power law and continuous and accurately approximates many practical scenarios. We derive the distributions of SIR, SNR, and finally SINR before finding the potential throughput scaling, which provides insight on the observed cell-splitting rate gain. The exact mathematical results show that the SIR monotonically decreases with Network density, while the converse is true for SNR, and thus the Network coverage probability in terms of SINR is maximized at some finite density. With ultra-densification (Network density goes to infinity), there exists a \emph{phase transition} in the near-field path loss exponent $\alpha_0$: if $\alpha_0 >1$ unbounded potential throughput can be achieved asymptotically; if $\alpha_0 <1$, ultra-densification leads in the extreme case to zero throughput.
Chung-ming Huang - One of the best experts on this subject based on the ideXlab platform.
-
v2v data offloading for Cellular Network based on the software defined Network sdn inside mobile edge computing mec architecture
IEEE Access, 2018Co-Authors: Chung-ming Huang, Duy-tuan Dao, Meng-shu Chiang, Huan ZhouAbstract:Data offloading plays an important role for the mobile data explosion problem that occurs in Cellular Networks. This paper proposed an idea and control scheme for offloading vehicular communication traffic in the Cellular Network to vehicle to vehicle (V2V) paths that can exist in vehicular ad hoc Networks (VANETs). A software-defined Network (SDN) inside the mobile edge computing (MEC) architecture, which is abbreviated as the SDNi-MEC server, is devised in this paper to tackle the complicated issues of VANET V2V offloading. Using the proposed SDNi-MEC architecture, each vehicle reports its contextual information to the context database of the SDNi-MEC server, and the SDN controller of the SDNi-MEC server calculates whether there is a V2V path between the two vehicles that are currently communicating with each other through the Cellular Network. This proposed method: 1) uses each vehicle’s context; 2) adopts a centralized management strategy for calculation and notification; and 3) tries to establish a VANET routing path for paired vehicles that are currently communicating with each other using a Cellular Network. The performance analysis for the proposed offloading control scheme based on the SDNi-MEC server architecture shows that it has better throughput in both the Cellular Networking link and the V2V paths when the vehicle’s density is in the middle.
-
Vehicle-to-Infrastructure (V2I) offloading from Cellular Network to 802.11p Wi-Fi Network based on the Software-Defined Network (SDN) architecture
Vehicular Communications, 2017Co-Authors: Chung-ming Huang, Hsiu Ming Pai, Duy-tuan Dao, Meng-shu Chiang, Shouzhi Xu, Huan ZhouAbstract:This paper proposes a prediction control scheme called Offloading with Handover Decision based on Software-Defined Network (OHD–SDN) for the offloading of the vehicle-to-infrastructure communication using the Software-Defined Network (SDN) Architecture. In the proposed control scheme, when the vehicle with an On Board Unit (OBU), which has a Cellular Network interface and an IEEE 802.11p Network interface, connects to Cellular Network, the SDN Controller monitors it to make decision about the offloading indication based on the reported information, including speed, geographical position, direction, and sensed neighboring RSUs' IDs, from the vehicle. The SDN Controller calculates when the due time is to make decision, decides whether it is suitable or not to have the vehicle to handoff from Cellular Network to the ahead IEEE 802.11p Network of a RSU, and then notifies the vehicle to stay in Cellular Network if the Networking situation of the ahead RSUs IEEE 802.11p Network is not suitable or to switch from Cellular Network to the ahead RSUs IEEE 802.11p Network if the Networking situation of the ahead RSU's IEEE 802.11p Network is suitable. The simulation results show that the Cellular Networks load and traffic can be reduced and the Networking quality of the vehicle being in the IEEE 802.11p Network of a RSU can be assured using the proposed OHD–SDN control scheme.
-
802.11p Wi-Fi Offloading from the Cellular Network to Vehicle-to-Infrastructure Communication Network Using the Software-Defined Network (SDN) Technique
Internet of Vehicles – Technologies and Services, 2016Co-Authors: Chung-ming Huang, Hsiu Ming Pai, Duy-tuan Dao, Meng-shu Chiang, Shouzhi Xu, Huan ZhouAbstract:Wi-Fi offloading is a technique for reducing 3G/3.5G/4G Cellular Network’s traffic load and users’ expense spent in 3G/3.5G/4G Cellular Network. Nevertheless, it needs to judge whether the offloading from the Cellular Network to the Wi-Fi Network is valuable or not by considering the target Wi-Fi Network’s situation. This paper proposed a Software Defined Network (SDN) –based method to pre-decide whether it is valuable to have offloading from the Cellular Network to the corresponding vehicle’s ahead 802.11p Wi-Fi RSU Network or not. By utilizing the centralization architecture and the information of the current contexts, including speed, position and direction, of vehicles, SDN Controller can calculate whether the Networking situation of the corresponding vehicle’s ahead 802.11p Wi-Fi RSU is good enough to offload or not before the vehicle enters into the signal coverage. The performance analysis shows that it can let vehicles have better Networking situation and quality using our proposed scheme.
Reza K. Farsani - One of the best experts on this subject based on the ideXlab platform.
-
Capacity Limits of Full-Duplex Cellular Network
IEEE Transactions on Information Theory, 2021Co-Authors: Kaiming Shen, Reza K. FarsaniAbstract:This paper aims to characterize the capacity limits of a wireless Cellular Network with a full-duplex (FD) base-station (BS) and half-duplex user terminals, in which three independent messages are communicated: the uplink message m1 from the uplink user to the BS, the downlink message m2 from the BS to the downlink user, and the device-to-device (D2D) message m3 from the uplink user to the downlink user. From an information theoretical perspective, the overall Network can be viewed as a generalization of the FD relay broadcast channel with a side message transmitted from the relay to the destination. We begin with a simpler case that involves the uplink and downlink transmissions of (m1, m2) only, and propose an achievable rate region based on a novel strategy that uses the BS as a FD relay to facilitate the interference cancellation at the downlink user. We also prove a new converse, which is strictly tighter than the cut-set bound, and characterize the capacity region of the scalar Gaussian FD Network without a D2D message to within a constant gap. This paper further studies a general setup wherein (m1, m2, m3) are communicated simultaneously. To account for the D2D message, we incorporate Marton’s broadcast coding into the previous scheme to obtain a larger achievable rate region than the existing ones in the literature. We also improve the cut-set bound by means of genie and show that by using one of the two simple rate-splitting schemes, the capacity region of the scalar Gaussian FD Network with a D2D message can already be reached to within a constant gap. Finally, a generalization to the vector Gaussian channel case is discussed. Simulation results demonstrate the advantage of using the BS as relay in enhancing the throughput of the FD Cellular Network.
-
capacity limits of full duplex Cellular Network
arXiv: Information Theory, 2019Co-Authors: Kaiming Shen, Reza K. FarsaniAbstract:This paper explores the capacity limits of a wireless Cellular Network with full-duplex (FD) base station (BS) and half-duplex user terminals, in which three independent messages are communicated, i.e., uplink message $m_1$ from the uplink user to the BS, downlink message $m_2$ from the BS to the downlink user, and D2D message $m_3$ from the uplink user to the downlink user. Information theoretically, this wireless system can be interpreted as a generalization of the FD relay broadcast channel with side message transmitted from relay to destination. Our study starts with a simpler case that has only the uplink and the downlink transmissions of $(m_1,m_2)$. For the discrete memoryless channel model, we propose a novel strategy that uses the BS as a FD relay to facilitate interference cancellation. The paper further provides a new converse which is strictly tighter than the cut-set bound. Taken together and specialized to the Gaussian case, our inner and outer bounds yield a characterization of the capacity to within a constant gap for the scalar and the vector Gaussian channel models. Furthermore, the paper studies a general setup with $(m_1,m_2,m_3)$. For the discrete memoryless channel model, we incorporate Marton's broadcast coding to obtain an achievable rate region, which is larger than the existing ones. Regarding the converse, we derive a nontrivial outer bound by means of genie. For the scalar Gaussian channel model, it is shown that by using one of the two rate-splitting schemes depending on the channel condition, we can already achieve the capacity to within a constant gap. For the vector Gaussian channel model, we further show how dirty paper coding can be applied to coordinate the transmissions of $(m_1,m_2,m_3)$ in three different ways. Finally, simulations demonstrate the advantages of using the BS as a relay in the FD Cellular Network.
-
capacity limits of full duplex Cellular Network
Information Theory Workshop, 2018Co-Authors: Kaiming Shen, Reza K. FarsaniAbstract:This paper explores the information theoretical capacity limits of uplink-downlink transmissions in a wireless Cellular Network with full-duplex FD base station (BS) and half-duplex user terminals. We recognize the cross-channel interference between the terminals as the main capacity bottleneck, and propose novel strategies that use BS as a relay to facilitate interference cancellation. We model the FD Cellular system as a two-user interference channel with an extra cross-link feedback from the uplink receiver to the downlink transmitter, and show that the feedback allows a larger achievable rate region than the conventional non-feedback schemes. This paper further provides a converse and shows that the proposed scheme achieves the capacity of the full-duplex Cellular Network to within a constant additive gap. Finally, this paper considers a new scenario in which the uplink terminal has additional information to transmit to the downlink terminal directly. Relaying by the BS is shown to play a crucial role in maximizing the achievable rates in this case.