Hybrid maximum-rate and proportional-fairness resource allocation in the downlink of LTE networks

The Long Term Evolution (LTE) network provides high bandwidth, flexible modulation and coding scheme for emerging mobile applications. The issues of power saving and quality of services are very critical for the success of deployment of mobile applications. This paper presents a buffer aware scheduling approach to reduce power consumption while maintaining the receiving quality of video streaming in LTE network. The proposed buffer aware scheduler considers the buffer length and channel conditions of the user equipment (UE) to allocate radio resource so that the UE can receive video data as much as possible when it is in the RRC_Connected state and has good channel condition, while it will stay in the RRC_Idle state as longer as possible to save power given that its reserved video data in the buffer is enough to play. Both of 720P and 1080P resolution video traffic models were applied for exhaustive simulations to examine the performance of the proposed scheme by comparing to that of the Proportional Fair (PF) scheme. The simulation results indicate that the proposed scheduling can significantly improve the power utilization, buffer underflow and system throughput.

The deployment of Long Term Evolution (LTE) networks in unlicensed spectrum is a promising solution to overcome the scarcity of licensed spectrum. Yet it has been widely observed that severe unfairness and performance degradation would occur when LTE coexists with WiFi, the incumbent user of unlicensed bands, without proper adjustment. Fair and efficient coexistence of these two networks thus becomes crucial. It, nevertheless, remains largely unknown how to optimize the total throughput of the LTE and WiFi networks under fairness constraints. To address the above open issue, this paper considers that a WiFi network coexists with an LTE network using the Category 3 or Category 4 Listen-Before-Talk (LBT) mechanism, and aims to characterize the maximum total throughput of the LTE and WiFi networks under two fairness constraints including throughput fairness and 3GPP fairness. The analysis shows that the maximum total throughput is independent of which LBT mechanism the LTE network adopts, and can be improved as the mean successful transmission time of the LTE network increases. Explicit expressions of the optimal initial backoff window sizes to achieve the maximum total throughput under both throughput fairness and 3GPP fairness are also derived, which shed important light on the practical network design. It is found that the initial backoff window size of the LTE network should be enlarged as the mean successful transmission time of the LTE network increases, indicating that for fair and efficient coexistence with a WiFi network, the LTE network needs to access the unlicensed channel infrequently with large packets. To facilitate implementation in practice, distributed schemes are further proposed, with which WiFi and LTE can optimally adjust the backoff window sizes based on their own observation and estimation without the need of coordination between these two networks.

In Long Term Evolution Advanced networks with Type I in‐band half‐duplex decode‐and‐forward relay nodes, proportional fair (PF) resource allocation is aiming at guaranteeing two‐hop match and optimising global proportional fairness. The two‐hop match is defined as equal data rates in the access links and the corresponding backhaul links. The global proportional fairness is between all the user equipments served by the evolved nodes B and the relay nodes. Existing centralised schemes achieve these targets at the cost of enormous channel state information (CSI) exchange. Existing distributed schemes focus on resource partitioning and employ a traditional single‐hop PF scheduling algorithm in access links, with less CSI exchange. The traditional PF scheduling algorithm maximises single‐hop proportional fairness between the data rates in the access links rather than two‐hop proportional fairness between the end‐to‐end data rates in the two hops. In order to reduce CSI exchange and at the same time to maximise the two‐hop proportional fairness, a distributed two‐hop PF resource allocation scheme is proposed. The proposed scheme includes two‐hop PF resource scheduling algorithms and adaptive resource partitioning algorithms, applied in different two‐hop transmission protocols. Simulation results demonstrate the proposed scheme is better than the existing distributed schemes in obtaining better proportional fairness and larger cell‐edge user equipment throughputs. Copyright © 2014 John Wiley & Sons, Ltd.

The growing demands for wireless communication services pose new challenges in the coming generation of cellular networks design. In Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) networks, ever-higher data rate and energy efficiency (EE) are required to meet the increasing demands in cellular traffic. High data rates can be achieved, however, it requires a high level of energy consumption, which needs to be controlled especially in this era of green communication trends. Hence, efficient solutions are necessary to optimize EE and at the same time achieve high data rates to meet green LTE requirements. This paper proposed an efficient algorithm, namely, the Quality of Service (QoS) and Energy Efficient Aware (QEEA). The goal of QEEA is to achieve maximum throughput and improve the EE by using low transmitted power (43 dBm), which is the lowest power setting according to the 3GPP LTE specifications. The proposed algorithm is compared against other scheduling algorithms, namely, the Channel and QoS Aware (CQA), Priority Set Scheduler (PSS), Proportional Fair (PF), Maximum Throughput (MT) and Blind Average Throughput (BAT). Besides that, the performance of QEEA is also analyzed when the transmit power is set to 43 dBm, 46 dBm, and 48 dBm. The simulation process was conducted using Network Simulator-3 (NS-3) and the performance of these packet scheduling algorithms was evaluated based on the performance of system throughput. The results showed that the QEEA algorithm outperformed the other algorithms as it could achieve up to 75% of throughput improvement in terms of radius ranging from 200 m to 1000 m and increasing number of users in the cell, which is 167.86% of. Thus, it can be concluded that QEEA algorithm is the best candidate to achieve the highest throughput.

LTE (Long Term Evolution) networks support a wide range of voice, data and video services. LTE networks are designed to deliver high rates of transmission, low latency and higher spectral efficiency than the current generation of 3G networks. However, due to the limited radio resources, it is important to take advantage of these resources efficiently. This way, an appropriate strategy to resource allocation gains utmost importance for the requirements of QoS (Quality of Service) to be achieved. This paper proposes a Resource Allocation Scheme in two layers that combines game theory and the Proportional Fair Scheduler, aiming at improving performance and justice in the distribution of radio resources. The results of the study of the performance based on modeling and simulation are satisfactory.

The femtocell networks, which is a small cellular base station in home and small business environment, is an attractive solution for operators to improve indoor coverage and network capability. In addition, relaying is one of the proposed technique for future releases of UTRAN Long Term Evolution (LTE) networks which aims to increase the coverage and capability of LTE networks. A LTE network is called as relay enhanced LTE network if the LTE network adopting the relays. A user can handover not only two relays, but also between relays and base stations, and two base stations. It is important to provide a seamlessly handover solution in the relay enhanced LTE network. During mobility, the packet loss problem is occurred if some packets are sent to the previous base station (or relay) when a user equipment (UE) is already handover to the current base station (or relay). To solve this problem, a data forwarding procedure is performed to re-direct these buffered packets from the previous base station (or relay) to the current base station (or relay). In this paper, we develop a new data forwarding protocol with the assistance of femtocells, called as a femtocell-assisted data forwarding, in the relay enhanced LTE networks to provide a seamlessly handover result with the low packet loss rate and the high throughput. Finally, the simulation results illustrate that our proposed protocol outperforms the existing data forwarding scheme.

Random Access Network (RAN) on IEEE 802.11x works based on Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA). Each frame on Wireless Local Network (WLAN) depends on data size. Long Term Evolution (LTE) network uses a preamble signature to access network via Physical Random Access Channel (PRACH). In order to access network, both WLAN and LTE operate based on the ALOHA mechanism. The advantage of CSMA/CA is that all stations can access network by waiting an idle channel. On the other hand, if the number of station is increased, collision may induce. On LTE network, it was designed to support a hug number of User Equipment (UE). All UEs can access network by using the preamble signature simultaneously in a preamble slot on contention based random access procedure. Data frame on LTE network can be very by Modulation Coding Scheme (MCS). In order to support fifth Generation (5G) mobile data technology in term of handover between cellular network and WLAN. In this paper, WLAN and LTE network technology are compared in order to show its performance in terms of delay, and throughput. The result shows that delay on WLAN is slightly increased when increases the number of station. LTE throughput can be varied by the MCS that makes the LTE network more flexible than WLAN technology.

The purpose of the paper is to examine if public long term evolution (LTE) network is suitable for smart grid (SG) automatic metering usage, in a suburban scenario, without causing significant hindrance to typical LTE traffic. In addition, the same generalized suburban scenario is evaluated with a hybrid sensor - LTE network where wireless sensor network (WSN) cluster heads are also equipped with LTE remote terminal units (RTUs). The simulation topology is formed as a suburban area that consists of single RTU per apartment/house for SG traffic and an average 3.7 people per habitat, each with their user equipment, using one of the available carriers. Normal SG traffic is generated in both directions, uplink and downlink. The worst-case usage factor is considered as a power outage, where all SG meters in the area of influence simultaneously detect and attempt to report such a failure. Thus, emergency SG traffic is generated simultaneous by all RTUs. To alleviate the problem of the high momentary SG emergency traffic load, two distinct solutions are proposed and simulated. As the first solution, an artificial, up to one-second random delay is introduced in the transmission scheduling of emergency messages. The second solution applies low-power WSNs at the cluster level and cluster heads that contain both 802.15.4 and LTE communication interfaces, i.e., a hybrid sensor-LTE network. The simulation results show that both of the solutions that try to alleviate the high instantaneous traffic loads can reach the quality of service criteria for SG traffic without compromising other public LTE traffic. The deciding factor to use either pure LTE approach or a hybrid sensor-LTE network comes from non-functional requirements of the system.

The LTE broadband evolved from an earlier Third Generation Partnership Project system which is known as the Universal Mobile Telecommunication System (UMTS), which evolved from the Global System for Mobile Communications (GSM). The network architecture of this system has been designed with the aim to support a packet-switched traffic with seamless mobility and great quality of service. The main goal of the LTE is to provide a high data rate with low latency and a packet optimized radio access technology that supports deployment of bandwidth. Hence, this study is based on the evaluation of the LTE network in the south-west region of Nigeria. This study evaluates the LTE network strength in the South-West region of Nigeria. Questionnaires were administered among users in these areas randomly. Thereafter, data were analyzed and research questions were answered from the analyzed results. The results showed that 9Mobile and MTN has the best quality of service of LTE network in South-West, Nigeria, also that the LTE network has not really been active in Osun and Ekiti states.

International audience

In this paper, we investigate the performance of an alternative received signal filtering technique based on local averaging to improve the quality of handover decisions in Long Term Evolution (LTE) networks. The focus of LTE-Advance (LTE-A) networks is to provide enhanced capacity and reliability of radio access as well as broadband demand for mobile users. The necessity to maintain quality of service, especially for the delay sensitive data services and applications, has made mobility and handover decisions between the base stations in the LTE networks critical. Unfortunately, several handover decision algorithms in the LTE networks are based on the Reference Signal Received Power (RSRP) obtained as a linear averaging over the reference signals. The critical challenge with the linear averaging technique is that the limited reference signal available in the downlink packet introduces an estimation error. This estimation error is a result of the effects of linear averaging on propagation loss components in eliminating fast-fading from the received signals. Moreover, prompt and precise handover decisions cannot be based on inaccurate measurement. The standardized LTE layer 3 filtering technique is applied to the local averaged layer 1 signal to render it suitable for LTE handover decisions. The local averaging technique produces better handover than the linear averaging technique in terms of the reduced number of handover failures, improved high spectral efficiency and increased throughput, especially for cell-edge users with high speeds. The findings of this study suggest that the local averaging technique enhances mobility performance of LTE-Advance networks.

The goal of this research is to evaluate the location accuracy of User Equipment (UE) in Long Term Evolution (LTE) networks which depends on the timing advance parameters. The ability to locate the subscribers through the network is considered as a significant factor in wireless communication systems. The main method to geolocation based on specified distances from many base stations is stated. The possibility of geolocating a Long Term Evolution (LTE) subscriber station based on the timing advance ranging parameter within the network signal internals is investigated in the paper. Also, simulation is used to describe performance in multiple base station networks that evaluating locations of subscriber stations on a two-dimensional system coordinated. Performance estimation of UE location in LTE networks was analyzed using simulations. Simulations were performed by using MATLAB. The main method for determining the subscriber station location depends on radial distances from multiple base stations. We observe from the results that the calculation error for the network is frivolous and by using four eNodeBs we obtain the most accurate estimation. Our simulation analysis shows that increasing the eNodeBs that used in the network leads to increasing the error to 29 centimeters.

Considering the computational complexity and fronthaul capacity requirements of network-wide centralized optimization for Cell-free (CF) massive multiple input multiple output (MIMO) networks, we focus on user-centric (UC) networks wherein each user is served by a subset of access points (APs) rather than all the APs. We study a proportional-fair resource allocation (RA) problem, including slot resource allocation and precoding design in UC networks over consecutive time-slots. We formulate the proportional-fair (PF) resource allocation problem as a series of weighted sum-rate maximization problems and develop a two-stage heuristic RA scheme to solve the problem. The scheme adopts a user grouping process to decompose resource allocation problem into intra-group orthogonal resource allocation sub-problems. A modularity-based user grouping algorithm upon a constructed weighted digraph is proposed. Then, relying on the grouping results, a parallel distributed PFRA algorithm consisting of user selection process and a Signal to Leakage plus Noise Ratio (SLNR)-based precoding design is proposed to fulfil intra-group resource allocation. Rather than global channel state information (CSI) collected from the whole network, local CSI obtained cooperatively within each AP subset is utilized in the proposed resource allocation scheme. Numerical results confirm that the proposed RA scheme outperforms in throughput while maintaining comparable fairness among users.

Performance management (PM) is critical for supporting end-to-end QoS (Quality of Service) across long term evolution (LTE) network elements over heterogeneous networks. In order to effectively deliver QoS traffic from different applications, LTE can be delivered through implementation of logical Class of Service (CoS)/QoS controls in a variety of methods and with variety services. While LTE network domains (e.g., Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Backhaul transport network, and Evolved Packet Core (EPC) network) can have different QoS implementations that work within a given domain, these differences can cause problems when domains intersect. Therefore, the design strategy must specifically and logically fit to allow multiple offers on limited network resources. This paper presents a high level PM system architecture for monitoring and troubleshooting harmonization of CoS/QoS based on 802.1p/DSCP (Diffserv Code Point)/EXP (EXPerimental bits) mappings that optimize end-to-end network performances over multiple LTE network elements.

One of the critical components of the Smart Grid (SG) is the Smart Meter (SM), which reports power consumption to a centralized control center at regular intervals. The Long Term Evolution (LTE) network has received much attention as a promising platform for SG communications due to its high bandwidth and low latency over a large coverage area. Nevertheless, when a huge number of SMs access the LTE network, the preamble collision becomes an issue. The negative effects of preamble collision are packet loss, delay, reestablishment attempts, and physical channel utilization, which degrade the performance of the LTE network. Hence, a Random Access (RA) mechanism is required for preamble signature to occupy Resource Blocks (RBs) for SMs. In this paper, we introduce a hybrid procedure that combines contention and non-contention based random access methods. The significance of this method is that, although SMs have fixed periodic communications, preamble signatures do not need to be reserved. The simulation results are compared with LTE standard. Packet loss is reduced by approximately 43%. SM latency is decreased by 11 ms at 90% of probability delay. Re-establishment attempts are lower than standard by proximately 76%. Finally, physical channel utilizations are reduced by around 3%.