A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> This paper addresses the performance of spatial division multiplexing (SDM) multiple-input multiple-output (MIMO) techniques together with frequency domain packet scheduling (FDPS) based on UTRAN long term evolution (LTE) downlink. Two SDM concepts currently considered in 3GPP are the single-user (SU-) and the multi-user (MU-) MIMO. For MU-MIMO, multiple users can be scheduled on different streams on the same time-frequency resource, while SU-MIMO restricts one time-frequency resource to a single user. Both concepts are analyzed against the 1times2 maximal ratio combining (MRC) case, using the proportional fair (PF) criterion extended to frequency and spatial domains. The realistic finite buffer best effort traffic model is used in the study. Results show that in the macrocell scenario, the combination of FDPS and SDM (SDM-FDPS) without preceding achieves only marginal gain in cell throughput, due to limited SINR dynamic range. The gain is increased to around 20% when precoding is applied. In the micro-cell scenario, the gain of SDM-FDPS over the reference scheme is increased up to 35% with precoding. <s> BIB001 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> This paper addresses the problem of frequency domain packet scheduling (FDPS) incorporating spatial division multiplexing (SDM) multiple input multiple output (MIMO) techniques on the 3GPP long term evolution (LTE) downlink. We impose the LTE MIMO constraint of selecting only one MIMO mode (spatial multiplexing or transmit diversity) per user per transmission time interval (TTI). First, we address the optimal MIMO mode selection (multiplexing or diversity) per user in each TTI in order to maximize the proportional fair (PF) criterion extended to frequency and spatial domains. We prove that the SU-MIMO (single-user MIMO) FDPS problem under the LTE requirement is NP-hard and therefore, we develop two approximation algorithms (one with full channel feedback and the other with partial channel feedback) with provable performance bounds. Based on 3GPP LTE system model simulations, the approximation algorithm with partial channel feedback is shown to have comparable performance to the one with full channel feedback, while significantly reducing the channel feedback overhead by nearly 50%. <s> BIB002 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Where this book is exceptional is that the reader will not just learn how LTE works but why it works Adrian Scrase, ETSI Vice-President, International Partnership Projects LTE - The UMTS Long Term Evolution: From Theory to Practice provides the reader with a comprehensive system-level understanding of LTE, built on explanations of the theories which underlie it. The book is the product of a collaborative effort of key experts representing a wide range of companies actively participating in the development of LTE, as well as academia. This gives the book a broad, balanced and reliable perspective on this important technology. Lucid yet thorough, the book devotes particular effort to explaining the theoretical concepts in an accessible way, while retaining scientific rigour. It highlights practical implications and draws comparisons with the well-known WCDMA/HSPA standards. The authors not only pay special attention to the physical layer, giving insight into the fundamental concepts of OFDMA, SC-FDMA and MIMO, but also cover the higher protocol layers and system architecture to enable the reader to gain an overall understanding of the system. Key Features: Draws on the breadth of experience of a wide range of key experts from both industry and academia, giving the book a balanced and broad perspective on LTE Provides a detailed description and analysis of the complete LTE system, especially the ground-breaking new physical layer Offers a solid treatment of the underlying advances in fundamental communications and information theory on which LTE is based Addresses practical issues and implementation challenges related to the deployment of LTE as a cellular system Includes an accompanying website containing a complete list of acronyms related to LTE, with a brief description of each (http://www.wiley.com/go/sesia_theumts) This book is an invaluable reference for all research and development engineers involved in LTE implementation, as well as graduate and PhD students in wireless communications. Network operators, service providers and R&D managers will also find this book insightful. <s> BIB003 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Discontinuous reception (DRX) is supported in 3GPP Long Term Evolution (LTE) to reduce power consumption of user equipments (UEs). Power conservation achieved via DRX can be further increased with a packet scheduler that takes DRX states into consideration. Thus, in addition to quality of service (QoS) and fairness factors, which have been the main focus so far in scheduler design, energy efficiency must also be considered in scheduling. In this paper, we introduce a DRX and QoS-aware uplink packet scheduling algorithm (DQEPS) for LTE networks. One of the main reasons of poor DRX utilization is the continuous uplink packet traffic generated by applications working in the background. Accordingly, we first layout the cumulative distribution functions (CDF) of inter-packet arrival durations constructed by inspecting uplink packet transmission for various applications. Then, we form metrics for each bearer using these CDFs along with the DRX states, QoS parameters, channel conditions, and the buffer status of the bearers. Using these metrics, we develop a scheduling algorithm for the uplink, which aims to maximize power conservation of DRX mechanism by scheduling packets in a way that tries to minimize ON duration, while meeting the QoS requirements. Performance evaluations indicate that DQEPS reduces power consumption significantly compared to the previously proposed methods for LTE. <s> BIB004 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Green communications has been paid much attention recently, to provide energy efficient networks with a high level of quality of service (QoS). In this study, the authors propose a cross-layer scheduling scheme for the downlink of long-term evolution networks, considering the buffer state which may be empty in some times. Their target is to minimise energy consumption under the constraints of limited average transmitting power in the base station, and maximum tolerable delay as QoS of heterogeneous users. In the proposed scheme, the authors use an effective capacity link layer model to consider the data link layer characteristics, such as probability of non-empty buffer and probability of maximum delay, along with the physical layer parameters. Simulation results show more than 48% reduction of energy consumption in peak traffic loads. <s> BIB005 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> This book focus on Long Term Evolution (LTE) and beyond. The chapters describe different aspects of research and development in LTE, LTE-Advanced (4G systems) and LTE-450 MHz such as telecommunications regulatory framework, voice over LTE, link adaptation, power control, interference mitigation mechanisms, performance evaluation for different types of antennas, cognitive mesh network, integration of LTE network and satellite, test environment, power amplifiers and so on. It is useful for researchers in the field of mobile communications. <s> BIB006 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> We present an approach to schedule Long Term Evolution (LTE) uplink (UL) Machine to Machine (M2M) traffic in a densely deployed heterogeneous network, over the lamp posts of a big boulevard for smart city applications. The small cells operate with frequency reuse 1 and Inter-Cell Interference (ICI) is a critical issue to manage. We consider a Release 9 3rd Generation Partnership Project (3GPP) compliant scenario, where Single Carrier Frequency Division Multiple Access (SC-FDMA) is selected as the multiple access scheme, which requires that all Resource Block (RB)s allocated to a single user have to be contiguous in frequency within each time slot. This adjacency constraint limits the flexibility of the Frequency-Domain Packet Scheduling (FDPS) and Inter-Cell Interference Coordination (ICIC), when trying to maximize the scheduling objectives, and this is sufficient to make the problem NP-hard. We aim to solve an optimization problem, taking into account criteria such as the maximization of the overall throughput, the minimization of the radio resource usage, and the minimization of ICI. This can be modelled through a Mixed Integer Linear Programming (MILP) and solved through a heuristic implementable in the standards. We present simulation results in a 3GPP compliant network simulator, which support the effectivity of our algorithm, for different M2M applications, with respect to state of the art approaches. <s> BIB007 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Long Term Evolution (LTE), a standard developed by the 3rd Generation Partnership Project (3GPP), is currently the 4G mainstream technology, providing technology convergence for this generation of cellular communication systems. LTE networks promise data transmission rates of 100 Mbps in the downlink channel. For this high throughput it needs to optimize the use of network resources. LTE uses scheduling techniques for radio resource allocation based on communication channel conditions. This paper presents a heuristic customizable algorithm for multi-user data scheduling in the LTE downlink channel that can prioritize selected types of services. The proposed scheduling scheme is a modified version of the proportional fairness scheduler that uses Analytic Hierarchy Process (AHP) techniques. This allows to aggregate performance criteria to improve resource allocation based on general traffic conditions and a set of predefined service priorities. The approach for this customization is to assign weights to certain parameters used in the resource allocation process, thus modifying the relative importance of these parameters and creating a hierarchy of criteria. Criteria for different types of data are added through comparison matrices. A comparison matrix quantifies the judgment of the decision maker with respect to the relative importance of different criteria. Thus the scheduler can be made flexible and adaptive to different traffic scenarios. Examples are given where video traffic is prioritized. <s> BIB008 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Anyone who has ever shopped for a new smart phone, laptop, or other tech gadget knows that staying connected is crucial. There is a lot of discussion over which service provider offers the best coverageenabling devices to work anywhere and at any timewith 4G and LTE becoming a pervasive part of our everyday language.The Handbook of Research on Next Generation Mobile Communication Systems offers solutions for optimal connection of mobile devices. From satellite signals to cloud technologies, this handbook focuses on the ways communication is being revolutionized, providing a crucial reference source for consumers, researchers, and business professionals who want to be on the frontline of the next big development in wireless technologies.This publication features a wide variety of research-based articles that discuss the future of topics such as bandwidth, energy-efficient power, device-to-device communication, network security and privacy, predictions for 5G communication systems, spectrum sharing and connectivity, and many other relevant issues that will influence our everyday use of technology. <s> BIB009 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> This book introduces the Vienna Simulator Suite for 3rd-Generation Partnership Project (3GPP)-compatible Long Term Evolution-Advanced (LTE-A) simulators and presents applications to demonstrate their uses for describing, designing, and optimizing wireless cellular LTE-A networks. Part One addresses LTE and LTE-A link level techniques. As there has been high demand for the downlink (DL) simulator, it constitutes the central focus of the majority of the chapters. This part of the book reports on relevant highlights, including single-user (SU), multi-user (MU) and single-input-single-output (SISO) as well as multiple-input-multiple-output (MIMO) transmissions. Furthermore, it summarizes the optimal pilot pattern for high-speed communications as well as different synchronization issues. One chapter is devoted to experiments that show how the link level simulator can provide input to a testbed. This section also uses measurements to present and validate fundamental results on orthogonal frequency division multiplexing (OFDM) transmissions that are not limited to LTE-A. One chapter exclusively deals with the newest tool, the uplink (UL) link level simulator, and presents cutting-edge results. In turn, Part Two focuses on system-level simulations. From early on, system-level simulations have been in high demand, as people are naturally seeking answers when scenarios with numerous base stations and hundreds of users are investigated. This part not only explains how mathematical abstraction can be employed to speed up simulations by several hundred times without sacrificing precision, but also illustrates new theories on how to abstract large urban heterogeneous networks with indoor small cells. It also reports on advanced applications such as train and car transmissions to demonstrate the tools capabilities. <s> BIB010 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Appropriate bandwidth allocation is an important issue to benefit the long Term Evolution (LTE) networks performance. Single-carrier FDMA (SC-FDMA) multiple access scheme has been chosen for the 3GPP LTE uplink scheduling. However, it requires that all the sub carriers allocated to a single user must be in contiguous frequency band within each time slot. This constraint limits the scheduling flexibility. The resource allocation algorithm in frequency domain must take this constrain into consideration to maximize its scheduling objectives. An Efficient Resource Allocation algorithm with Grey Relational Analysis (ERAGRA) is proposed and compared with the others algorithms based on the throughput and fairness in this research. The ERAGRA algorithm is a channel-aware traffic resource allocation algorithm which aims at enabling uplink traffic delivery on ideal and non-ideal channels. This algorithm is evaluated using 3GPP LTE simulation model. A key performance index (KPI) is defined as the combination of total throughput and fairness. ERAGRA and two other scheduling algorithms: Best CQI and Round Robin has been evaluated through simulation based on this KPI. Simulation results indicate that the proposed ERAGRA algorithm effectively improves the average normalized system throughput of Best CQI by 6.22 % and fairness by 2.74 %, while improves the average normalized system throughput of Round Robin by 38.67 % and fairness by 10.26 %. The proposed scheduling scheme achieves a near optimal solution for maximizing system throughput and fairness of resource utilization. <s> BIB011 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> To support a high density of mobile devices and its connections by means of rapid increase of mobile devices as well as small cells, various studies related to random access such as the random access load, better uplink resource utilization and interference among random access attempts have been developed for enhanced long-term evolution (LTE) system and 5G communication technology. In this paper, we discuss about the technical issues of random access resource configuration in time division duplex (TDD) mode and propose an improved method of it to make better uplink resource utilization on frequency domains and to minimize interference among random access attempts for physical random access channel (PRACH) resource allocation point of view, but it can also easily extend the LTE system. The proposed method is compared with LTE TDD PRACH configuration method through theoretical analysis. It shows that the proposed method provides better resource utilization for PRACH and physical uplink shared channel resources (PUSCH), allows flexible resource utilization in uplink scheduling, and is intuitive and effective in cell deployment with random access channel optimization in terms of random access resource configuration. <s> BIB012 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Long Term Evolution (LTE) wireless communication system has adopted Orthogonal Frequency Division Multiple Access (OFDMA) technology to provide downlink transmissions to multiple User Equipment (UE) in a single transmission time interval. In OFDMA, UEs provide quantized channel quality information, called channel quality indicator (CQI), to the base station. CQI feedback is then used at the base station to choose which UE to be scheduled and which modulation and coding scheme (MCS) for the selected UE to be used in downlink transmissions. Each UE sends averaged CQI over all subcarriers instead of sending the CQI of each subcarrier to minimize feedback overhead. As a result, only one MCS is applied at the base station for multiple subcarriers intended for the same UE. This can cause significant throughput degradation, especially in low SNR regions in which the actual CQI of each subcarrier may vary significantly. Our experimental results show that the two well-known scheduling algorithms, namely Best CQI and Proportional Fair Scheduling (PFS), fail to provide spectrum efficiency and/or fairness among UEs. These algorithms tend to provide a large fraction of bandwidth to a single UE; hence, the UE fails to demodulate transmitted data to which only one modulation scheme was applied. In this paper, we propose a novel scheduling algorithm that achieves better throughput performance, while providing more fairness among UEs than existing solutions in both high and low SNR environments. The proposed algorithm improves cell throughput by 66% over the PFS when UEs experience various SNR values. When UEs undergo similar SNR values, the system throughput can be improved by more than 120% over BestCQI and by almost 60% over PFS. Extensive simulations validate that our proposed solution also significantly enhance Block Error ratio (BLER) in addition to network throughput and fairness. <s> BIB013 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> In this book, three different methods are presented to enhance the capacity and coverage area in LTE-A cellular networks. The scope involves the evaluation of the effect of the RN location in terms of capacity and the determination of the optimum location of the relay that provides maximum achievable data rate for users with limited interference at the cell boundaries. This book presents a new model to enhance both capacity and coverage area in LTE-A cellular network by determining the optimum location for the RN with limited interference. The new model is designed to enhance the capacity of the relay link by employing two antennas in RN. This design enables the relay link to absorb more users at cell edge regions. An algorithm called the Balance Power Algorithm (BPA) is developed to reduce MR power consumption. The book pertains to postgraduate students and researchers in wireless & mobile communications. <s> BIB014 </s> A Research Survey on Scheduling Techniques in lte-based Network and its State of Art <s> Introduction <s> Time–frequency resource conversion (TFRC) is a recently proposed network resource allocation strategy. By exploiting user behavior, it withdraws and reutilizes spectrum resources strategically from connection(s) not being focused on by the user to relieve network congestion effectively. In this paper, we study downlink scheduling based on TFRC for a Long-Term Evolution (LTE)-type cellular network to maximize service delivery. The service scheduling of interest is formulated as a joint request, channel and slot allocation problem, which is NP-hard. A deflation and sequential fixing based algorithm with only polynomial-time complexity is proposed to solve the problem. For practical implementation, we propose TFRC-enabled low-complexity yet online scheduling algorithms, which integrate prediction-based leaky bucket-like traffic shaping and modified Smith ratio or exponential capacity based utility function. Furthermore, by establishing a charging model for the relationship between TFRC-enabled scheduling and its TFRC-disabled counterpart, we analytically study the benefits of integrating TFRC with scheduling. Simulation results not only verify the analysis of impact of key parameters on the performance improvement but corroborate the benefits of integrating TFRC with scheduling techniques in terms of quality-of-service provisioning and resource utilization as well. <s> BIB015
The Long-Term Evolution (LTE) is aims to cater up the exponentially increasing demands of the dynamic users of cellular network  . LTE offers maximized rate of transmission with much reduced network delay and simplified operational cost  . The LTE scheduling process in LTE is used to get proper resource allocation to assist the variable demands of resources during data transmission process BIB003 . The scheduling process is designed for considering the explicit condition of the communication channel, volume of traffic, and quality of service BIB006 . A good scheduler will have a potential dependencies on gain factor involved in channel state associated with each users as well as sub-carriers. To offer lower delay in scheduling process, the standards of LTE claims of offering 1msecs of duration involved in data forwarding process  . The scheduling processes are always considered to be carried out over base station. While executing the scheduling decision, the base station performs allocation of resources considering both downlink as well as uplink transmission BIB014  . Currently, LTE uses Orthogonal Frequency Division Multiplexing (OFDM) or OFDM Access (OFDMA) for uplink transmission while the downlink transmission is assisted by Single-Carrier Frequency Division Multiple Access (SC-FDMA). The scheduling in LTE is very much different from other form of technologies of accessing, where LTE based scheduling are carried out considering both time and frequency domain for users while other access technologies are limited to only time domain BIB009 . The problem associated with the scheduling process in LTE is all about identifying the precise allocation of scheduling blocks to specific user equipment's for the purpose of increasing cumulative throughput or minimizing network delay BIB010 . In order to avoid any issues, the present research work towards schedulers are designed to be functional in two process i.e. scheduling packet using time domain first and then execute frequency domain BIB007 BIB011 BIB012 BIB013  BIB015   BIB004 BIB005 BIB008 . There also existing certain research work that uses multiple-input multiple-output as a scheme to design scheduler for LTE networks BIB002 BIB001 . There has been various work carried out towards LTE network; however; various problems and issues are still demanding more investigation. The existing research work are not found to report any form of extensive supportability of spatial multiplexing during both uplink and downlink transmission for more number of layers in order to increase the transmission rates. There is also a significant problems associated with both the uplink and downlink transmission when they were made to work in multipoint forwarding and receiving of packets for increasing the throughput and coverage of extended rate of data. It is also found that adoption of relaying methodologies towards improving the optimal usage of communication channel as well as its associated capacity has been less explored. All these problems are unsolved and unaddressed and require a good series of dedicated investigation in order to explore a better form of solution. Hence, this paper reviews the existing approaches towards scheduling process in LTE-based network and deliberately attempts to identify the potential research gap. The idea is to assist the upcoming researchers to measure the level of effectiveness in existing scheduling techniques. The organization of this paper is as follows: Section 2 discusses about the theoretical briefing of LTE followed by exhaustive review of existing scheduling practices in Section 3. Section 4 discusses about research gap while Section 5 briefs about the contribution of this paper followed by tentative future work direction. The next section discusses about the existing approaches used to address the scheduling problems in LTE.