scholarly journals Impact of Feedback Channel Delay over Joint User Scheduling Scheme and Separated Random User Scheduling Scheme in LTE-A System with Carrier Aggregation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ahmed A. Ali ◽  
Rosdiadee Nordin ◽  
Mahamod Ismail ◽  
Huda Abdullah
Keyword(s):  
Base Station ◽  
Wireless Channel ◽  
Main Beam ◽  
Carrier Aggregation ◽  
User Scheduling ◽  
Current Channel ◽  
Scheduling Scheme ◽  
Channel Quality ◽  
Measurement Results ◽  
The Impact

In Long Term Evolution-Advanced (LTE-A), the signal quality in a wireless channel is estimated based on the channel quality measurements. The measurement results are used to select suitable modulation and coding scheme for each transmission, feedback, and processing delay, which can cause a mismatch between channel quality information (CQI) and current channel state at the base station. However, prospect delays in the reception of such CQI may lead to a system performance degradation. This study analyzes the impact of CQI feedback delay on joint user scheduling (JUS) scheme and separated random user scheduling (SRUS) scheme in LTE-A system over carrier aggregation. The analysis will be compared with the system having delayed channel and perfect knowledge at different deployment scenario. We will study the throughput performance of both scheduling schemes with different deployment scenario, and then recommend the suitable deployment scenario to keep the desired QoS for a specific number of users. Results show that, in main beam directed at sector boundaries and diverse coverage, JUS scheme performs better than SRUS, which can justify the intensive use of user equipment power and extra control signaling overhead.

A Fast Scheduling Algorithm for Multiple User MIMO-MRC System

2013 ◽  
Vol 385-386 ◽  
pp. 1738-1742
Author(s):  
Dong Tang ◽  
Ming Xia Lv
Keyword(s):  
Computational Complexity ◽  
Mimo System ◽  
Scheduling Algorithm ◽  
Low Complexity ◽  
Base Station ◽  
User Group ◽  
User Scheduling ◽  
Channel Quality ◽  
Multiple User ◽  
The Cost

When multiple users share the same channel at one time, the total throughput of the communication system can be maximized by allocating the common radio resource to the user or the user group having the best channel quality at a given time and the multiuser diversity gain can be obtained. The object to select the users in the best group is to select the users with the maximum sum capacity. Because of the co-channel interferences among the users, user in the best group is often not the user with the best channel quality when only does it transmit to the base station. As for a scheduling algorithm, exhaustive algorithm is to search the whole possibilities of the user group and is an approach that can get the largest capability of the system by multi-user scheduling. However, this algorithm is quite complex and usually brings huge workload to a base station with multiple antennas, hence the cost of operation to a base station has substantially increased. We propose a fast user selection algorithm with low complexity to reduce the computational complexity of the scheduling algorithm. From the simulation results, this algorithm not only decreases the computational complexity of the scheduling algorithm but also retains large capability of the MIMO system.

scholarly journals Joint Cell Muting and User Scheduling in Multicell Networks with Temporal Fairness

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Shahram Shahsavari ◽  
Nail Akar ◽  
Babak Hossein Khalaj
Keyword(s):  
Transmission Rate ◽  
General Pattern ◽  
Base Station ◽  
User Scheduling ◽  
Cell Level ◽  
Worst Case ◽  
Selection Decisions ◽  
A Cell ◽  
Center Section ◽  
The Impact

A semicentralized joint cell muting and user scheduling scheme for interference coordination in a multicell network is proposed under two different temporal fairness criteria. In the proposed scheme, at a decision instant, each base station (BS) in the multicell network employs a cell-level scheduler to nominate one user for each of its inner and outer sections and their available transmission rates to a network-level scheduler which then computes the potential overall transmission rate for each muting pattern. Subsequently, the network-level scheduler selects one pattern to unmute, out of all the available patterns. This decision is shared with all cell-level schedulers which then forward data to one of the two nominated users provided the pattern they reside in was chosen for transmission. Both user and pattern selection decisions are made on a temporal fair basis. Although some pattern sets are easily obtainable from static frequency reuse systems, we propose a general pattern set construction algorithm in this paper. As for the first fairness criterion, all cells are assigned to receive the same temporal share with the ratio between the temporal share of a cell center section and that of the cell edge section being set to a fixed desired value for all cells. The second fairness criterion is based on max-min temporal fairness for which the temporal share of the network-wide worst case user is maximized. Extensive numerical results are provided to validate the effectiveness of the proposed schemes and to study the impact of choice of the pattern set.

scholarly journals Impact of scheduling algorithms on the performance of telemedicine traffic in cellular networks

2021 ◽  
Vol 9 (2) ◽  
pp. 13-27
Author(s):  
E. J. Obamila ◽  
Keyword(s):  
Cellular Networks ◽  
Medical Information ◽  
Scheduling Algorithms ◽  
Base Station ◽  
Medical Data ◽  
Traffic Load ◽  
Critical Data ◽  
Scheduling Scheme ◽  
The Impact ◽  
Efficient Transmission

Efficient transmission of medical information is an emerging area of telecommunication engineering because it conveys critical data about a patient’s state and vital measurements. Consequently, it is required that such transmissions be accelerated and errorless. This requirement is beyond the norm of only scheduling users at a Base Station but calls for the provisioning of guaranteed bandwidth for transmission of these critical medical data. To achieve this, there is a need to develop a scheduling scheme that will prioritize all forms of Telemedicine traffic over regular traffic at the Base Station. But there is also the need to measure, evaluate and quantify the impact of the developed scheduling scheme on telemedicine traffic transmission in cellular networks in terms of the throughputs attained. To address these problems, priority and non-priority based scheduling algorithms for telemedicine traffic transmission were developed and simulated using MATLAB 8.1.0 software and the impact of the developed algorithm on telemedicine traffic transmission was evaluated. The result represents a significant increase in telemedicine user’s throughputs with a priority scheduling scheme. Over 20 rounds, the impact of packet sizes, traffic load conditions and codec rates on the average throughputs of telemedicine traffics were studied and discussed.

scholarly journals Energy-Efficient Packet Forwarding Scheme Based on Fuzzy Decision-Making in Underwater Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4368
Author(s):  
Jitander Kumar Pabani ◽  
Miguel-Ángel Luque-Nieto ◽  
Waheeduddin Hyder ◽  
Pablo Otero
Keyword(s):  
Energy Consumption ◽  
Sensor Networks ◽  
Energy Efficient ◽  
Real Life ◽  
Base Station ◽  
Fuzzy Decision Making ◽  
Underwater Sensor Networks ◽  
Packet Forwarding ◽  
Node Number ◽  
The Impact

Underwater Wireless Sensor Networks (UWSNs) are subjected to a multitude of real-life challenges. Maintaining adequate power consumption is one of the critical ones, for obvious reasons. This includes proper energy consumption due to nodes close to and far from the sink node (gateway), which affect the overall energy efficiency of the system. These wireless sensors gather and route the data to the onshore base station through the gateway at the sea surface. However, finding an optimum and efficient path from the source node to the gateway is a challenging task. The common reasons for the loss of energy in existing routing protocols for underwater are (1) a node shut down due to battery drainage, (2) packet loss or packet collision which causes re-transmission and hence affects the performance of the system, and (3) inappropriate selection of sensor node for forwarding data. To address these issues, an energy efficient packet forwarding scheme using fuzzy logic is proposed in this work. The proposed protocol uses three metrics: number of hops to reach the gateway node, number of neighbors (in the transmission range of a node) and the distance (or its equivalent received signal strength indicator, RSSI) in a 3D UWSN architecture. In addition, the performance of the system is also tested with adaptive and non-adaptive transmission ranges and scalable number of nodes to see the impact on energy consumption and number of hops. Simulation results show that the proposed protocol performs better than other existing techniques or in terms of parameters used in this scheme.

scholarly journals The Impact of Elongation on Change in Electrical Resistance of Electrically Conductive Yarns Woven into Fabric

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3390
Author(s):  
Željko Knezić ◽  
Željko Penava ◽  
Diana Šimić Penava ◽  
Dubravko Rogale
Keyword(s):  
Mathematical Model ◽  
Electrical Resistance ◽  
Electrically Conductive ◽  
Textile Materials ◽  
Measurement Results ◽  
Conductive Yarns ◽  
Yarn Count ◽  
As Relationship ◽  
The Impact ◽  
The Mathematical Model

Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.

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