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Showing papers on "LTE Advanced published in 2017"


Journal ArticleDOI
26 Jul 2017
TL;DR: The overview of requirements and use cases in V2X services in 3GPP is presented, and the up-to-date standardization of LTE V2x in 3 GPP is surveyed, where the enhanced V2Z (eV2X) services and possible 5G solutions are analyzed.
Abstract: Vehicle-to-everything (V2X), including vehicle- to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-infrastructure (V2I), and vehicle-to-network (V2N) communications, improves road safety, traffic efficiency, and the availability of infotainment services. Standardization of Long Term Evolution (LTE)-based V2X has been actively conducted by the Third Generation Partnership Project (3GPP) to provide solutions for V2X communications, and has benefited from the global deployment and fast commercialization of LTE systems. LTE-based V2X was widely used as LTE-V in the Chinese vehicular communications industry, and LTE-based V2X was redefined as LTE V2X in 3GPP standardization progress. In this article, the overview of requirements and use cases in V2X services in 3GPP is presented. The up-to-date standardization of LTE V2X in 3GPP is surveyed. The challenges and detailed design aspects in LTE V2X are also discussed. Meanwhile, the enhanced V2X (eV2X) services and possible 5G solutions are analyzed. Finally, the implementations of LTE V2X are presented with the latest progress in industrial alliances, research, development of prototypes, and field tests.

670 citations


Journal ArticleDOI
TL;DR: Key features for FD-MIMO systems are presented, a summary of the major issues for the standardization and practical system design, and performance evaluations for typical FD- MIMO scenarios are presented.
Abstract: Multiple-input multiple-output (MIMO) systems with a large number of base station antennas, often called massive MIMO, have received much attention in academia and industry as a means to improve the spectral efficiency, energy efficiency, and processing complexity of next generation cellular systems. The mobile communication industry has initiated a feasibility study of massive MIMO systems to meet the increasing demand of future wireless systems. Field trials of the proof-of-concept systems have demonstrated the potential gain of the Full-Dimension MIMO (FD-MIMO), an official name for the MIMO enhancement in the 3rd generation partnership project (3GPP). 3GPP initiated standardization activity for the seamless integration of this technology into current 4G LTE systems. In this article, we provide an overview of FD-MIMO systems, with emphasis on the discussion and debate conducted on the standardization process of Release 13. We present key features for FD-MIMO systems, a summary of the major issues for the standardization and practical system design, and performance evaluations for typical FD-MIMO scenarios.

215 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a collision resolution random access model for massive MTC over LTE/LTE-A. The proposed model basically resolves the preamble collisions instead of avoidance and targets the management of massive and bursty access attempts.
Abstract: Massive MTC over cellular networks is expected to be an integral part of wireless smart city applications. The LTE/LTE-A technology is a major candidate for provisioning of MTC applications. However, due to the diverse characteristics of payload size, transmission periodicity, power efficiency, and QoS requirement, MTC poses huge challenges to LTE/LTE-A technologies. In particular, efficient management of massive random access is one of the most critical challenges. In the case of massive random access attempts, the probability of preamble collision drastically increases, and thus the performance of LTE/LTE-A random access degrades sharply. In this context, this article reviews the current state-of-the-art proposals to control massive random access of MTC devices in LTE/LTE-A networks. The proposals are compared in terms of five major metrics: access delay, access success rate, power efficiency, QoS guarantee, and the effect on HTC. To this end, we propose a novel collision resolution random access model for massive MTC over LTE/LTE-A. Our proposed model basically resolves the preamble collisions instead of avoidance and targets the management of massive and bursty access attempts. Simulations of our proposed model show huge improvements in random access success rate compared to the standard slotted-Aloha- based models. The new model can also coexist with existing LTE/LTE-A MAC protocol and ensure high reliability and time-efficient network access.

139 citations


Journal ArticleDOI
TL;DR: The measurements reveal that LTE can provide coverage for 99 percent of the outdoor and road users, but the LTE-M or NarrowBand-IoT upgrades are required in combination with other measures to allow for additional penetration losses, such as those experienced in underground parking lots.
Abstract: Long Term Evolution, the fourth generation of mobile communication technology, has been commercially deployed for about five years. Even though it is continuously updated through new releases, and with LTE Advanced Pro Release 13 being the latest one, the development of the fifth generation has been initiated. In this article, we measure how current LTE network implementations perform in comparison with the initial LTE requirements. The target is to identify certain key performance indicators that have suboptimal implementations and therefore lend themselves to careful consideration when designing and standardizing next generation wireless technology. Specifically, we analyze user and control plane latency, handover execution time, and coverage, which are critical parameters for connected mobility use cases such as road vehicle safety and efficiency. We study the latency, handover execution time, and coverage of four operational LTE networks based on 19,000 km of drive tests covering a mixture of rural, suburban, and urban environments. The measurements have been collected using commercial radio network scanners and measurement smartphones. Even though LTE has low air interface delays, the measurements reveal that core network delays compromise the overall round-trip time design requirement. LTE's breakbefore- make handover implementation causes a data interruption at each handover of 40 ms at the median level. While this is in compliance with the LTE requirements, and lower values are certainly possible, it is also clear that break-before-make will not be sufficient for connected mobility use cases such as road vehicle safety. Furthermore, the measurements reveal that LTE can provide coverage for 99 percent of the outdoor and road users, but the LTE-M or NarrowBand-IoT upgrades, as of LTE Release 13, are required in combination with other measures to allow for additional penetration losses, such as those experienced in underground parking lots. Based on the observed discrepancies between measured and standardized LTE performance, in terms of latency, handover execution time, and coverage, we conclude the article with a discussion of techniques that need careful consideration for connected mobility in fifth generation mobile communication technology.

107 citations


Journal ArticleDOI
TL;DR: This paper evaluates the maximum aggregate throughput, offloading efficiency, and in particular, the delay performance of FiWi enhanced LTE-Advanced (LTE-A) heterogeneous networks (HetNets), and develops a decentralized routing algorithm for FiWiEnhanced LTE-A HetNet.
Abstract: To cope with the unprecedented growth of mobile data traffic, we investigate the performance gains obtained from unifying coverage-centric 4G mobile networks and capacity-centric fiber-wireless (FiWi) broadband access networks based on data-centric Ethernet technologies with resulting fiber backhaul sharing and WiFi offloading capabilities. Despite recent progress on backhaul-aware 4G studies with capacity-limited backhaul links, the performance-limiting impact of backhaul latency and reliability has not been examined in sufficient detail previously. In this paper, we evaluate the maximum aggregate throughput, offloading efficiency, and in particular, the delay performance of FiWi enhanced LTE-Advanced (LTE-A) heterogeneous networks (HetNets), including the beneficial impact of various localized fiber-lean backhaul redundancy and wireless protection techniques, by means of probabilistic analysis and verifying simulation, paying close attention to fiber backhaul reliability issues and WiFi offloading limitations due to WiFi mesh node failures as well as temporal and spatial WiFi coverage constraints. We use recent and comprehensive smartphone traces of the PhoneLab data set to verify whether the previously reported assumption that the complementary cumulative distribution function of both WiFi connection and interconnection times fit a truncated Pareto distribution is still valid. In this paper, we put a particular focus on the 5G key attributes of very low latency and ultra-high reliability and investigate how they can be achieved in FiWi enhanced LTE-A HetNets. Furthermore, given the growing interest in decentralization of future 5G networks (e.g., user equipment assisted mobility), we develop a decentralized routing algorithm for FiWi enhanced LTE-A HetNets.

90 citations


Journal ArticleDOI
TL;DR: A step-by-step tutorial discussing the development of MTC design across different releases of LTE and the newly introduced user equipment categories, namely, MTC category (CAT-M) and narrowband IoT category ( CAT-N).
Abstract: Human-generated information has been the main interest of the wireless communication technologies designs for decades. However, we are currently witnessing the emerge of an entirely different paradigm of communication introduced by machines, and hence, the name machine type communication (MTC). Such paradigm arises as a result of the new applications included in the Internet-of-Things (IoT) framework. Among the enabling technologies of the IoT, cellular-based communication is the most promising and more efficient. This is justified by the currently well-developed and mature radio access networks, along with the large capacities and flexibility of the offered data rates to support a large variety of applications. On the other hand, several radio-access-network groups put efforts to optimize the 3GPP LTE standard to accommodate for the new challenges by introducing new communication categories paving the way to support the machine-to-machine communication within the IoT framework. In this paper, we provide a step-by-step tutorial discussing the development of MTC design across different releases of LTE and the newly introduced user equipment categories, namely, MTC category (CAT-M) and narrowband IoT category (CAT-N). We start by briefly discussing the different physical channels of the legacy LTE. Then we provide a comprehensive and up-to-date background for the most recent standard activities to specify CAT-M and CAT-N technologies. We also emphasize on some of necessary concepts used in the new specifications, such as the narrowband concept used in CAT-M and the frequency hopping. Finally, we identify and discuss some of the open research challenges related to the implementation of the new technologies in real life scenarios.

87 citations


Journal ArticleDOI
TL;DR: It is shown that CoMP leads to both network throughput and capacity expansion in Long Term Evolution Advanced (LTE-A) network and can significantly provide more enhancements in spectrum efficiency and network performance gain with better cooperative coordination strategies.

83 citations


Journal ArticleDOI
TL;DR: This work proposes a cross-layer relay selection scheme that considers several criteria jointly, including end-to-end data rate, relay-capable UE (RUE) remaining battery time, and end- to-end transmission delay on relay-assisted D2D path, and shows how to leverage these criteria at an eNB performing relay selection in D1D communications.
Abstract: Device-to-device (D2D) communication is a promising technique for traffic offloading in next-generation cellular systems. However, the use of only direct D2D communications limits the advantages of D2D communications due to relatively long separation distances or poor link quality between source and destination user equipments (UEs). Relay-assisted D2D communication was proposed as a supplement to direct D2D communications for enhancing traffic offloading capacity in long-term evolution–advanced (LTE-A) systems. This work aims to design a relay UE selection strategy for D2D communications, which improves D2D communication performance significantly. We propose a cross-layer relay selection scheme that considers several criteria jointly, including end-to-end data rate, relay-capable UE (RUE) remaining battery time, and end-to-end transmission delay on relay-assisted D2D path. We show how to leverage these criteria at an eNB performing relay selection in D2D communications. In particular, an end-to-end delay estimation model is established based on queuing theory. Simulation results validate the performance of the proposed scheme in terms of total amount of data transmitted under RUE remaining battery and end-to-end transmission delay.

79 citations


Proceedings ArticleDOI
13 Jun 2017
TL;DR: This paper provides a description of the ProSe implementation that extends the LTE model already available in ns-3 and provides validation of each feature by comparing simulation results with analytical models developed as part of the work on D2D communication.
Abstract: The ability to perform device-to-device (D2D) communication in Long Term Evolution (LTE)-based cellular networks became possible with the introduction of Proximity Services (ProSe) functionalities in the 3rd Generation Partnership Program (3GPP) specifications. In this paper, we provide a description of the ProSe implementation that extends the LTE model already available in ns-3. Our model contains key features defined in LTE Release 12 and further enhanced in LTE Release 13 related to synchronization, discovery, and communication. We also provide validation of each feature by comparing simulation results with analytical models developed as part of our work on D2D communication.

63 citations


Journal ArticleDOI
TL;DR: Numerical results show that the proposed algorithm outperforms traditional Greedy algorithm in terms of throughput maximization while satisfying QoS requirements, and its performance is close to the optimal design.
Abstract: Providing diverse and strict quality-of-service (QoS) guarantees is one of the most important requirements in machine-to-machine (M2M) communications, which is particularly need for appropriate resource allocation for a large number of M2M devices. To efficiently allocate resource blocks (RBs) for M2M devices while satisfying QoS requirements, we propose group-based M2M communications, in which M2M devices are clustered based on their wireless transmission protocols, their QoS characteristics, and their requirements. To perform joint RB and power allocation in SC-FDMA-based LTE-A networks, we formulate a sum-throughput maximization problem, while respecting all the constraints associated with SC-FDMA scheme, as well as QoS requirements in M2M devices. The constraints in uplink SC-FDMA air interface in LTE-A networks complicate the resource allocation problem. We solve the resource allocation problem by first transforming it into a binary integer programming problem and then formulate a dual problem using the Lagrange duality theory. Numerical results show that the proposed algorithm outperforms traditional Greedy algorithm in terms of throughput maximization while satisfying QoS requirements, and its performance is close to the optimal design.

63 citations


Proceedings ArticleDOI
21 May 2017
TL;DR: A Software Defined Networking (SDN)-based MEC framework is proposed and implemented, compliant with both ETSI and 3GPP architectures, which provides the required data-plane flexibility and programmability, which can on-the-fly improve the latency as a function of the network deployment and conditions.
Abstract: Mobile Edge Computing (MEC) consists of deploying computing resources (CPU, storage) at the edge of mobile networks; typically near or with eNodeBs. Besides easing the deployment of applications and services requiring low access to the remote server, such as Virtual Reality and Vehicular IoT, MEC will enable the development of context-aware and context-optimized applications, thanks to the Radio API (e.g. information on user channel quality) exposed by eNodeBs. Although ETSI is defining the architecture specifications, solutions to integrate MEC to the current 3GPP architecture are still open. In this paper, we fill this gap by proposing and implementing a Software Defined Networking (SDN)-based MEC framework, compliant with both ETSI and 3GPP architectures. It provides the required data-plane flexibility and programmability, which can on-the-fly improve the latency as a function of the network deployment and conditions. To illustrate the benefit of using SDN concept for the MEC framework, we present the details of software architecture as well as performance evaluations.

Journal ArticleDOI
TL;DR: The control plane structure of LTE/LTE-A is reviewed and a comprehensive discussion of handover procedures such as the phases, techniques, requirements, features, and challenges involved are presented.
Abstract: The increasing demand for mobile communication calls for improvements to network operating services in terms of capacity, coverage, and Quality of Services (QoS). Ensuring QoS is one of the challenges faced by wireless network operators, which include the provision of high mobility speeds, thus the implementation of a seamless and fast handover between network cells is a prominent issue that must be addressed, especially when fulfilling QoS prerequisites. Long Term Evolution (LTE)/LTE-Advance has met these demands of QoS through the use of a new Radio Access Network and distribution of Radio Resource Management including the handover decision technique to evolve NodeB instead of relying on centralized control. In this paper, we review the control plane structure of LTE/LTE-A and present a comprehensive discussion of handover procedures such as the phases, techniques, requirements, features, and challenges involved. According to the overview of the handover decision phase, we surveyed and classified the present handover decision algorithms for a LTE-A system-based technology in regard to the primary handover decision technique. For each class, we describe in detail the fundamental operations and decision parameters using representative algorithms. A summary of input parameters, techniques, and performance evaluation of the handover decision algorithms concludes this work.

Journal ArticleDOI
TL;DR: This paper proposes a novel privacy-preserving with non-frameability handover authentication protocol based on (t, n) secret sharing to fit in with all of the mobility scenarios in the LTE/LTE-A networks, which is called Nframe.
Abstract: Seamless handover between the evolved universal terrestrial radio access network and other access networks is highly desirable to mobile equipments in the long term evolution (LTE) or LTE-Advanced (LTE-A) networks, but ensuring security and efficiency of this process is challenging. In this paper, we propose a novel privacy-preserving with non-frameability handover authentication protocol based on (t, n) secret sharing to fit in with all of the mobility scenarios in the LTE/LTE-A networks, which is called Nframe. To the best of our knowledge, Nframe is the first to support protecting users’ privacy with non-frameability in the handover process. Moreover, Nframe uses pairing-free identity based cryptographic method to secure handover process and to achieve high efficiency. The formal verification by the AVISPA tool shows that Nframe is secure against various malicious attacks and the simulation result indicates that it outperforms the existing schemes in terms of computation and communication cost.

Proceedings ArticleDOI
07 Jun 2017
TL;DR: In this paper two different strategies for power network monitoring and control are compared: an LTE-based centralized management approach and a 5G-based distributed management approach.
Abstract: In Smart Grids the flow of electricity and information is strictly interrelated with the management and control of the electricity supply system. ICT is not only an extension or a modernization of the power system equipment, but a fundamental requirement for supporting the distribution network monitoring, operation and control. To enable monitoring and control of the Smart Grid and accommodate the large realtime data flow between controlled equipment and the distribution management system it is necessary the deployment of advanced sensors and measurement systems along with the communication network infrastructure. In this paper two different strategies for power network monitoring and control are compared: an LTE-based centralized management approach and a 5G-based distributed management approach. The two types of communications systems are compared considering their performances during fault management in a Smart Grid scenario.

Journal ArticleDOI
TL;DR: An efficient scheme for concurrent M2M and H2H access on the PRACH is described, which separates the resources for M1M and M1H access at the level of preamble codes and avoids the use of the four-step handshake for M2m terminals by implementing a carrier sense multiple access with collision avoidance (CSMA/CA) overlay network using the designated preambl codes.
Abstract: When a large number of machine-to-machine (M2M) terminals attempt to access the Long-Term Evolution (LTE)/LTE Advanced (LTE-A) cellular network using the physical random access channel (PRACH), congestion and overload may result, which can lead to serious degradation of performance for both M2M and human-to-human (H2H) terminals. The main cause for this is the inherent complexity of the four-way handshake used for random access, which is well suited for H2H terminal access but unsuitable for massive M2M access. In this paper, we describe an efficient scheme for concurrent M2M and H2H access on the PRACH, which separates the resources for M2M and H2H access at the level of preamble codes and avoids the use of the four-step handshake for M2M terminals by implementing a carrier sense multiple access with collision avoidance (CSMA/CA) overlay network using the designated preamble codes. We analyze the performance of the scheme for both H2H and M2M traffic and show the values of the most important design parameters that enable this scheme to support concurrent access by H2H and M2M terminals with little performance degradation.

Journal ArticleDOI
TL;DR: The challenges and potential of unsupervised LTE D2D (mode 2) for safety-critical vehicle-to-everything (V2X) communications are evaluated and two distributed resource allocation strategies for unlicensed band access are proposed.
Abstract: In this article, we explore the recent Third Generation Partnership Project (3GPP) long-term evolution (LTE) device-to-device (D2D) radio resource management specification (Release 14) to identify the challenges and evaluate the potential of unsupervised LTE D2D (mode 2) for safety-critical vehicle-to-everything (V2X) communications. We also propose two distributed resource allocation strategies for unlicensed band access. Complementary to dedicated short-range communication (DSRC)/intelligent transport system (ITS)-G5, unsupervised LTE D2D presents an opportunity to provide redundancy for ultrareliable systems, such as safety-critical V2X communications.

Proceedings ArticleDOI
01 May 2017
TL;DR: This paper deals with Study and understanding of the existing LTE system, mainly about the different resouce allocation methods to employed and proposes a new novel algorithm for both UL and DL scheduling of resources.
Abstract: The hugely increasing demand for mobile broadband access to internet based services will soon challenge even the Universal Mobile Telecommunication Systems (UMTS), Long Term Evolution (LTE) cellular technology and its future enhancements. The Quality of Service (QoS) provisioning is an important issue in the mobility management of wireless femtocell networks of LTE technology. According to the scheduler allocates resources, required QoS of the user with use of Resource Blocks (RBs) based on the received channel condition feedback form the User Equipments (UEs) in the form of Channel Quality Indicator (CQI). There are several scheduling algorithms are existing, but fails to meet the QoS requirement simultaneously along with scheduling disciplines for communications for public safety users that are demanded to intervene in case of special events or in post disaster area where extremely high peaks of internet capacity required. The existing study on LTE Advanced (LTE-A) scheduling is mostly limited to unidirectional method of resource allocation in Uplink Link (UL) or Down Link (DL), separately. But, there are some works on the bidirectional UL-DL scheduling in other wireless technologies. There is scope of research in the upcoming years in UL-DL joint scheduling in LTE-A system. This paper deals with Study and understanding of the existing LTE system, mainly about the different resouce allocation methods to employed and proposes a new novel algorithm for both UL and DL scheduling of resources. The proposed work aims to bring the fairness among the end users with reduced delay.

Journal ArticleDOI
TL;DR: This paper presents an analytical model for the performance evaluation of the LTE-A RA procedure that incorporates the access class barring (ACB) scheme, which can be easily adapted to incorporate modifications of network parameters and/or extensions to the LTE -A system.
Abstract: The performance evaluation of the random access (RA) in LTE-A has recently become a major research topic as these networks are expected to play a major role in future 5G networks. Up to now, the key performance indicators (KPIs) of the RA in LTE-A have been obtained either by performing a large number of simulations or by means of analytic models that, oftentimes, sacrifice precision in exchange for simplicity. In this paper, we present an analytical model for the performance evaluation of the LTE-A RA procedure that incorporates the access class barring (ACB) scheme. By means of this model, each and every one of the KPIs suggested by the 3GPP can be obtained with minimal error when compared with results obtained by simulation. To the best of our knowledge, this paper presents the most accurate analytical model, which can be easily adapted to incorporate modifications of network parameters and/or extensions to the LTE-A system. In addition, our model of the ACB scheme can be easily incorporated to other analytic models of similar nature without further modifications.

Proceedings ArticleDOI
01 May 2017
TL;DR: A redundancy seriesparallel model is introduced to improve reliability of LTE eMBMS E2E services via redundancy, virtualized network functions (VNF), and autonomic service placement.
Abstract: Mobile Operators have experienced a growth of demand of new services with strict requirements and features which imposes challenges to operate the mobile wireless network. To tackle these challenges, Telcos must provide flexible, dynamic network architecture, furnishing resiliency to ensure end-to-end (E2E) service continuity in case of resource failures. Virtualization of the core network elements of cellular Long-Term Evolution (LTE) and LTE evolved Multimedia Broadcast Multicast Service (eMBMS) technology has been proposed as a key solution to cope with these new demands. By employing point-to-multipoint services to any wireless device, the LTE eMBMS, allows Mobile Operators (MOs) to send a single stream of data to all mobile users in a specific area. The LTE eMBMS is a potential E2E service technology to leverage costumer experience as well as to optimize use of network resources. We propose to improve the reliability of LTE eMBMS E2E services via redundancy, virtualized network functions (VNF), and autonomic service placement. In this paper, we introduce a redundancy seriesparallel model to improve reliability of LTE eMBMS services. The model is formulated as a VNF redundancy allocation problem (RAP). We employed the particle swarm optimization (PSO) technique to solve the RAP problem to evaluate the performance of the proposed model.

Journal ArticleDOI
TL;DR: A secure handover session key management scheme via mobile relay in LTE-A networks that can successfully establish session keys between the on-board UEs and their connected DeNB, achieving backward and forward key separations, and resisting against the collusion between the MRN and the DeNB as the same time.
Abstract: Internet of Things is expanding the network by integrating huge amount of surrounding objects which requires the secure and reliable transmission of the high volume data generation, and the mobile relay technique is one of the efficient ways to meet the on-board data explosion in LTE-Advanced (LTE-A) networks. However, the practice of the mobile relay will pose potential threats to the information security during the handover process. Therefore, to address this challenge, in this paper, we propose a secure handover session key management scheme via mobile relay in LTE-A networks. Specifically, in the proposed scheme, to achieve forward and backward key separations, the session key shared between the on-board user equipment (UE) and the connected donor evolved node B (DeNB) is first generated by the on-board UE and then securely distributed to the DeNB. Furthermore, to reduce the communication overhead and the computational complexity, a novel proxy re-encryption technique is employed, where the session keys initially encrypted with the public key of the mobility management entity (MME) will be re-encrypted by a mobile relay node (MRN), so that other DeNBs can later decrypt the session keys with their own private keys while without the direct involvement of the MME. Detailed security analysis shows that the proposed scheme can successfully establish session keys between the on-board UEs and their connected DeNB, achieving backward and forward key separations, and resisting against the collusion between the MRN and the DeNB as the same time. In addition, performance evaluations via extensive simulations are carried out to demonstrate the efficiency and effectiveness of the proposed scheme.

Posted Content
Jiayi Zhang1, Deng Likai1, Xu Li1, Yuchuan Zhou1, Yanan Liang1, Ying Liu1 
TL;DR: Compared with existing schemes, the performance of the proposed scheme can be significantly enhanced in terms of the discovery probability and the discovery delay, and several useful guidelines for its design are proposed based on the analysis.
Abstract: Device-to-Device (D2D) discovery is a key enabler of D2D communications for the direct exchange of local area traffic between proximity users (UEs) to improve spectral efficiency. The direct D2D discovery relies on the capabilities of the D2D UEs to autonomously indicate their presence to proximity D2D UEs. {Despite} its potential of reducing energy and signalling burden, the direct D2D discovery {has not drawn adequate attention}. In this paper, we propose a direct D2D discovery scheme based on the random backoff procedure, where D2D UEs randomly choose a backoff interval and retransmit a beacon. Compared with existing schemes, the performance of the proposed scheme can be significantly enhanced in terms of the discovery probability and the discovery delay. Several useful guidelines for its design are proposed based on our analysis. Finally, numerical results provide valuable insights on the performance tradeoff inherent to the proposed D2D discovery scheme.

Journal ArticleDOI
TL;DR: A hybrid, error correction-based, neural network to predict the path loss for suburban areas at 800 MHz and 2600 MHz is presented, obtained by combining empirical propagation models, ECC-33, Ericsson 9999, Okumura Hata, and 3GPP's TR 36.942, with a backpropagation Artificial Neural Network (ANN).
Abstract: This article presents the development and analysis of a hybrid, error correction-based, neural network to predict the path loss for suburban areas at 800 MHz and 2600 MHz, obtained by combining empirical propagation models, ECC-33, Ericsson 9999, Okumura Hata, and 3GPP's TR 36.942, with a backpropagation Artificial Neural Network (ANN). The network performance was tested along with two optimization techniques - Genetic Algorithm (GA) and Least Mean Square (LMS). Results were compared with data obtained by measurements performed in the vicinity of the Federal University of Rio Grande do Norte (UFRN), in the city of Natal, Brazil. In the end, the hybrid neural network presented the best results, indicating greater similarity with experimental data. The results developed in this research will help to achieve better signal estimation, reducing errors in planning and implementation of LTE and LTE-A systems.

Journal ArticleDOI
TL;DR: A stochastic geometry based framework to analyze the coverage probability and average data rate of a three-hop M2M network deployed along with User Equipments (UEs) and extensive simulations to study the system performance show that the three- Hopkins formed from out-of-range MTC devices and UEs can significantly improve the coverage and average rate of the entire network.
Abstract: With a wide range of applications, Machine-to-Machine (M2M) communication has become an emerging technology for connecting generic machines to the Internet. To ensure ubiquity in connections across all machines, it is necessary to have a standard infrastructure, such as 3GPP LTE-A network infrastructure, that facilitates such type of communications. However, owing to the huge scale of ?> machines to be deployed in near future and the nature of data transactions, ensuring ubiquitous connections among all the machines will be difficult. Solutions that not only maintain connectivity but also route machine data in a cost effective manner are the need of the hour. In this context, it has been suggested that Device-to-Device (D2D) communication can play a very important role in expanding network coverage and routing the data between source-destination machine pairs. In this paper, we conduct a feasibility study to highlight the impact of multi-hop D2D communication in increasing the network coverage and average rate of a Machine Type Communication (MTC) device. We present a stochastic geometry based framework to analyze the coverage probability and average data rate of a three-hop M2M network deployed along with User Equipments (UEs) and conduct extensive simulations to study the system performance. Our simulation results show that the three-hop M2M network formed from out-of-range MTC devices and UEs can significantly improve the coverage and average rate of the entire network. Due to the mobility of users in the network, design of robust routing mechanisms in such a time evolving network becomes difficult. Hence, we suggest the use of space-time graph built from the predicted user locations to design a cost efficient multi-hop D2D topology that enables routing of MTC data to its destination.

Journal ArticleDOI
TL;DR: A group-to-route handover authentication scheme based on trajectory prediction for mobile relays that can accomplish the mutual authentication and key agreement between the MRN group and the target DeNB with ideal efficiency in terms of authentication signaling overhead, bandwidth consumption, and computational cost.
Abstract: The introduction of mobile relay node (MRN) in long-term evolution advanced high-speed rail networks is an attractive method to provide uninterrupted connectivity for the group of user equipments on board. However, MRNs still suffer from frequent handovers and several security threats due to several rounds of message exchange and the insecure air interface between MRNs and donor eNBs (DeNBs). In this paper, we propose a group-to-route handover authentication scheme based on trajectory prediction for mobile relays. By our scheme, all of the DeNBs deployed along the trajectory can be formed a route-DeNB group and all of the MRNs deployed in the same train can construct a MRN group. Compared with the current 3GPP standards and other related schemes, our scheme can accomplish the mutual authentication and key agreement between the MRN group and the target DeNB with ideal efficiency in terms of authentication signaling overhead, bandwidth consumption, and computational cost. Security analysis by using the BAN logic and formal verification tool Scyther show that our scheme can work correctly and withstand several protocol attacks.

Journal ArticleDOI
TL;DR: The novel multi-level soft frequency reuse (MSFR) scheme, where the users in three different regions of a macro/micro cell adopt distinct frequency segments and different transmission power levels, is proposed.
Abstract: This paper deals with the planning of two-layer long-term evolution-advanced cellular systems, taking both the co-tier and cross-tier interference into account. In particular, we propose the novel multi-level soft frequency reuse (MSFR) scheme, where the users in three different regions of a macro/micro cell adopt distinct frequency segments and different transmission power levels. The optimization of power control parameters and cell association with MSFR results in a non-convex problem. We present the iterative-MSFR (I-MSFR) scheme, where the main optimization problem is divided into two sub-problems that can be subsequently solved by means of classical optimization methods. Finally, we propose two simplified schemes that achieve a comparable performance as I-MSFR in terms of utility, cell capacity, and outage conditions. I-MSFR and the simplified schemes have shown better performance than other schemes in the literature.

Journal ArticleDOI
TL;DR: This paper presents a framework for selecting which communications should use the D1D mode, and when, and allocating resources to D2D and non-D2D users, exploiting reuse for the former by proposing a heuristic solution to the second.
Abstract: Network-controlled device-to-device (D2D) communication allows cellular users to communicate directly, i.e., without passing through the eNodeB, while the latter retains control over resource allocation. This allows the same time---frequency resources to be allocated to spatially separated D2D flows simultaneously, thus increasing the cell throughput. This paper presents a framework for: (1) selecting which communications should use the D2D mode, and when, and (2) allocating resources to D2D and non-D2D users, exploiting reuse for the former. We show that the two problems, although apparently similar, should be kept separate and solved at different timescales in order to avoid problems, such as excessive packet loss. We model both as optimization problems, and propose a heuristic solution to the second, which must be solved at millisecond timescales. Simulation results show that our framework is practically viable, it avoids the problem of packet losses, increases throughput and reduces delays.

Journal ArticleDOI
TL;DR: A novel and efficient self-optimizing HO detection along with HO execution and decision parameter optimization algorithm which is named as Handover Detection Self-Organizing-HO Parameters (HD-SOHP) based on Reinforcement Learning (RL) concept which improves the users’ mobility performance by achieving effective session handovers.

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TL;DR: It has been demonstrated that the efficiency of a contract-based mechanism with asymmetric information is close to the optimal method (where the network resources are allocated based on the precise CSI) and the contract- based method outperforms the other relevant resource allocation techniques in terms of the total network service rate and signal-to-noise ratio.
Abstract: We study the problem of joint user association and intercell interference (ICI) mitigation in heterogeneous long-term evolution advanced (LTE-A) networks, presuming the absence of the precise global channel state information (CSI). We confront this problem from a contract-theoretic perspective and model the considered network as a labor market where the LTE evolved NodeBs (eNBs) are regarded as the employers offering a contract to the employees (cellular users). We explore a scenario where the wireless channels are ordered into different types according to their link gains and the cost of power consumption. It is assumed that each user knows the type of its channel but is not aware of the types of the channels belonging to other users. Hence, the channel type is regarded as the private information which is known only by the corresponding user. Under the presence of such asymmetric information, the eNBs formulate the optimal contract given by a set of the contract items (the combinations of user association, allocated spectrum, and power) and pass these items to the users, who then select the best contract items according to their channel types. The performance of a proposed contract-based resource allocation mechanism has been evaluated using the OPNET-based simulations. It has been demonstrated that the efficiency of a contract-based mechanism with asymmetric information is close to the optimal method (where the network resources are allocated based on the precise CSI). It has also been shown that the contract-based method outperforms the other relevant resource allocation techniques in terms of the total network service rate and signal-to-noise ratio.

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TL;DR: This paper proposes an adaptive and potential aware scheduling scheme (APASS), which is standard compliant and covers a wide range of scheduling objectives and outperforms other state-of-the-art scheduling schemes in terms of user satisfaction and delay.
Abstract: In this paper, we focus on uplink scheduling with the practical constraints imposed by the Long-Term Evolution/Long-Term Evolution-Advanced (LTE/LTE-A) standard. We consider multimedia traffic generated by mobile users with heterogeneous quality-of-service (QoS) requirements. To tackle the resulting time and frequency problem, we then propose an adaptive and potential aware scheduling scheme (APASS), which is standard compliant and covers a wide range of scheduling objectives. This scheduling scheme is composed of three algorithms, which work jointly to provide an efficient solution. Our performance evaluation shows that the APASS outperforms other state-of-the-art scheduling schemes in terms of user satisfaction and delay.

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TL;DR: This paper investigates profitability for network operators with the spectrum-energy efficiency metric on the downlink of LTE Advanced communication systems by employing the techniques of cell size zooming, user migration, and sleep mode in the deployment of different base station types.
Abstract: Heterogeneous networks have been pointed out to be one of the key network architectures that help increase system capacity and reduce power consumption for efficient communications. Although conceivably, high operational efficiency brings a high profit for mobile service providers, it is noteworthy that the potential for maximizing the profit has not been explored for the heterogeneous environment. This paper investigates profitability for network operators with the spectrum-energy efficiency metric on the downlink of LTE Advanced communication systems. We pursue optimal policies by employing the techniques of cell size zooming, user migration, and sleep mode in the deployment of different base station types. The problem is formulated as a quasiconvex optimization problem and it is transformed into an equivalent form of the MILP problem; the former is solved with a bisection algorithm and the latter is approached by an off-the-shelf software package. Since the formulated optimization problem is NP hard, a sub-optimal approach with a lower computational complexity is also proposed. Numerical analysis through case studies are presented to evaluate the efficiency improvements, and demonstrate the performance of the near-optimal solution.