This document discusses improving the performance of TCP congestion control over LTE-Advanced networks. It proposes a new congestion avoidance mechanism that uses the available bandwidth of the connection to better detect the network path capacity and improve congestion avoidance. The mechanism is tested using the NS-2 network simulator to model LTE-Advanced traffic. The document provides background on LTE-Advanced network architecture and existing TCP congestion control mechanisms. It aims to develop an enhanced TCP variant that can efficiently transfer high data rates over the large bandwidth, low latency links of LTE-Advanced networks.
Traffic offloading impact on the performanceIJCNCJournal
Long Term Evolution (LTE) is defined by the Third Generation Partnership Project (3GPP) standards as
Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users
and their applications are increasing, which increases the demand on the system BW. A new feature of the
LTE-Advanced (LTE-A) which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA), this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. In addition to the Carrier Aggregation feature, LTE-A supports Heterogeneous Networks (HetNets). HetNets consists of a mix of macro-cells, remote radio heads, and low power nodes such as pico-cells, and femto-cells. HetNets allow cellular network operators to support higher data traffic
by offloading it to a smaller cells such as femto-cells. The aim of this paper is to evaluate the Quality of Service (QoS) performance of the Modified Largest Weighted Delay First (MLWDF), the Exponential Rule (Exp-Rule), and the Logarithmic Rule (Log-Rule) scheduling algorithms while offloading 50% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to ten femto-cells, and to compare it with the case in-which traffic offloading is not
applied. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate (PLR), average packet delay, and fairness among users. The LTE-Sim-5 with modifications is used in the simulation process. Simulation results show that offloading 100% of the Macro-cell's traffic to five femtocells had the highest maximum throughput, and the best PLR values especially when using the Log-Rule, in-which using it maintained the PLR values around 0.15 despite increasing the number of users. The least average packet delay was achieved when offloading 100% of the Macro-cell's traffic to ten femto-cells, the delay dropped to below 5 ms. The fairness indicators for the three scheduling algorithms while traffic
offloading was applied fluctuated in a linear way between a range of values of 0.7 and 0.9.
QOS-B ASED P ERFORMANCE E VALUATION OF C HANNEL -A WARE /QOS-A WARE S CHEDULI...csandit
This document evaluates the quality of service performance of three channel-aware/QoS-aware scheduling algorithms (Modified Largest Weighted Delay First, Exponential Rule, Logarithmic Rule) for video applications over LTE and LTE-Advanced networks. It first provides background on LTE network architecture and operation. It then describes how the simulator was modified to implement carrier aggregation in LTE-Advanced, allowing evaluation of scheduling performance with increased bandwidth. Simulation results show that carrier aggregation improved average throughput, reduced packet loss and delay, and increased fairness compared to LTE without aggregation.
This document analyzes the performance of the LTE physical layer under 3GPP standards parameters. It summarizes an analysis of downlink and uplink throughput for LTE operating in both FDD and TDD modes with different system bandwidths, antenna configurations, modulation schemes, and coding rates. The key results showed that LTE can support downlink throughputs up to 300Mbps with 20MHz bandwidth using MIMO 4x4, and uplink throughputs up to 75Mbps.
This document summarizes a study on the performance of LTE networks. The researchers conducted passive and active measurements on a commercial LTE network with over 300,000 users to analyze network characteristics and resource utilization. They found that while LTE provides higher bandwidth than 3G, TCP flows often underutilize available bandwidth due to factors like limited receive windows. On average, flows used only 52% of available bandwidth, lengthening transfers and wasting energy. The researchers developed techniques to estimate bandwidth and identify inefficient application behaviors to recommend protocol and design improvements.
FREQUENCY AND TIME DOMAIN PACKET SCHEDULING BASED ON CHANNEL PREDICTION WITH ...ijwmn
1) The document discusses packet scheduling algorithms for LTE downlink systems that must operate under imperfect channel quality information (CQI) due to errors, delays, and other issues.
2) It proposes a new packet scheduling algorithm that uses a Kalman filter-based channel predictor in the frequency domain to estimate the true CQI from erroneous feedback, combined with a time domain grouping technique using proportional fair and modified largest weighted delay first algorithms.
3) Simulation results showed this approach achieves better performance than existing algorithms in terms of system throughput and packet loss ratio under imperfect CQI conditions.
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
Concurrent Multi - Path Real Time Communication Control Protocol (Cmprtcp)IRJET Journal
The document proposes a new transport protocol called Concurrent Multi-Path Real Time Communication Control Protocol (CMPRTCP) to handle real-time streams like video and audio over IP networks. CMPRTCP intelligently uses multiple paths between multi-homed hosts to concurrently transmit synchronized streams. It describes CMPRTCP's architecture and operation in detail. Experiments show CMPRTCP performs better than other protocols by maximizing timely data delivery under varying network conditions.
This document discusses the requirements for an LTE-capable transport network to deliver an optimized end-user experience. It focuses on capacity and latency. For capacity, a "single-peak, all-average" model is recommended that balances maximum capacity and economic feasibility. Latency must be low enough for applications like online gaming, with LTE offering latency around 20ms but the transport network also needing optimization to deliver that experience end-to-end. Dimensioning, aggregation, and latency guidelines are provided to help design an LTE transport network.
Traffic offloading impact on the performanceIJCNCJournal
Long Term Evolution (LTE) is defined by the Third Generation Partnership Project (3GPP) standards as
Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users
and their applications are increasing, which increases the demand on the system BW. A new feature of the
LTE-Advanced (LTE-A) which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA), this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. In addition to the Carrier Aggregation feature, LTE-A supports Heterogeneous Networks (HetNets). HetNets consists of a mix of macro-cells, remote radio heads, and low power nodes such as pico-cells, and femto-cells. HetNets allow cellular network operators to support higher data traffic
by offloading it to a smaller cells such as femto-cells. The aim of this paper is to evaluate the Quality of Service (QoS) performance of the Modified Largest Weighted Delay First (MLWDF), the Exponential Rule (Exp-Rule), and the Logarithmic Rule (Log-Rule) scheduling algorithms while offloading 50% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to ten femto-cells, and to compare it with the case in-which traffic offloading is not
applied. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate (PLR), average packet delay, and fairness among users. The LTE-Sim-5 with modifications is used in the simulation process. Simulation results show that offloading 100% of the Macro-cell's traffic to five femtocells had the highest maximum throughput, and the best PLR values especially when using the Log-Rule, in-which using it maintained the PLR values around 0.15 despite increasing the number of users. The least average packet delay was achieved when offloading 100% of the Macro-cell's traffic to ten femto-cells, the delay dropped to below 5 ms. The fairness indicators for the three scheduling algorithms while traffic
offloading was applied fluctuated in a linear way between a range of values of 0.7 and 0.9.
QOS-B ASED P ERFORMANCE E VALUATION OF C HANNEL -A WARE /QOS-A WARE S CHEDULI...csandit
This document evaluates the quality of service performance of three channel-aware/QoS-aware scheduling algorithms (Modified Largest Weighted Delay First, Exponential Rule, Logarithmic Rule) for video applications over LTE and LTE-Advanced networks. It first provides background on LTE network architecture and operation. It then describes how the simulator was modified to implement carrier aggregation in LTE-Advanced, allowing evaluation of scheduling performance with increased bandwidth. Simulation results show that carrier aggregation improved average throughput, reduced packet loss and delay, and increased fairness compared to LTE without aggregation.
This document analyzes the performance of the LTE physical layer under 3GPP standards parameters. It summarizes an analysis of downlink and uplink throughput for LTE operating in both FDD and TDD modes with different system bandwidths, antenna configurations, modulation schemes, and coding rates. The key results showed that LTE can support downlink throughputs up to 300Mbps with 20MHz bandwidth using MIMO 4x4, and uplink throughputs up to 75Mbps.
This document summarizes a study on the performance of LTE networks. The researchers conducted passive and active measurements on a commercial LTE network with over 300,000 users to analyze network characteristics and resource utilization. They found that while LTE provides higher bandwidth than 3G, TCP flows often underutilize available bandwidth due to factors like limited receive windows. On average, flows used only 52% of available bandwidth, lengthening transfers and wasting energy. The researchers developed techniques to estimate bandwidth and identify inefficient application behaviors to recommend protocol and design improvements.
FREQUENCY AND TIME DOMAIN PACKET SCHEDULING BASED ON CHANNEL PREDICTION WITH ...ijwmn
1) The document discusses packet scheduling algorithms for LTE downlink systems that must operate under imperfect channel quality information (CQI) due to errors, delays, and other issues.
2) It proposes a new packet scheduling algorithm that uses a Kalman filter-based channel predictor in the frequency domain to estimate the true CQI from erroneous feedback, combined with a time domain grouping technique using proportional fair and modified largest weighted delay first algorithms.
3) Simulation results showed this approach achieves better performance than existing algorithms in terms of system throughput and packet loss ratio under imperfect CQI conditions.
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
Concurrent Multi - Path Real Time Communication Control Protocol (Cmprtcp)IRJET Journal
The document proposes a new transport protocol called Concurrent Multi-Path Real Time Communication Control Protocol (CMPRTCP) to handle real-time streams like video and audio over IP networks. CMPRTCP intelligently uses multiple paths between multi-homed hosts to concurrently transmit synchronized streams. It describes CMPRTCP's architecture and operation in detail. Experiments show CMPRTCP performs better than other protocols by maximizing timely data delivery under varying network conditions.
This document discusses the requirements for an LTE-capable transport network to deliver an optimized end-user experience. It focuses on capacity and latency. For capacity, a "single-peak, all-average" model is recommended that balances maximum capacity and economic feasibility. Latency must be low enough for applications like online gaming, with LTE offering latency around 20ms but the transport network also needing optimization to deliver that experience end-to-end. Dimensioning, aggregation, and latency guidelines are provided to help design an LTE transport network.
The document describes a proposed unified algorithm for load balancing (LB) and handover optimization (HOO) in Long-Term Evolution (LTE) networks. The algorithm uses a Fuzzy System (FS) tuned by the Q-Learning reinforcement learning algorithm to modify handover parameters at the cell adjacency level. This aims to improve key performance indicators related to both LB and HOO. Simulation results show the proposed joint algorithm provides better performance than independent LB and HOO entities operating simultaneously. The algorithm reduces complexity for the self-organizing network coordination entity by handling LB and HOO jointly rather than as separate functions.
Improving Performance of TCP in Wireless Environment using TCP-PIDES Editor
Improving the performance of the transmission
control protocol (TCP) in wireless environment has been an
active research area. Main reason behind performance
degradation of TCP is not having ability to detect actual reason
of packet losses in wireless environment. In this paper, we are
providing a simulation results for TCP-P (TCP-Performance).
TCP-P is intelligent protocol in wireless environment which
is able to distinguish actual reasons for packet losses and
applies an appropriate solution to packet loss.
TCP-P deals with main three issues, Congestion in
network, Disconnection in network and random packet losses.
TCP-P consists of Congestion avoidance algorithm and
Disconnection detection algorithm with some changes in TCP
header part. If congestion is occurring in network then
congestion avoidance algorithm is applied. In congestion
avoidance algorithm, TCP-P calculates number of sending
packets and receiving acknowledgements and accordingly set
a sending buffer value, so that it can prevent system from
happening congestion. In disconnection detection algorithm,
TCP-P senses medium continuously to detect a happening
disconnection in network. TCP-P modifies header of TCP
packet so that loss packet can itself notify sender that it is
lost.This paper describes the design of TCP-P, and presents
results from experiments using the NS-2 network simulator.
Results from simulations show that TCP-P is 4% more
efficient than TCP-Tahoe, 5% more efficient than TCP-Vegas,
7% more efficient than TCP-Sack and equally efficient in
performance as of TCP-Reno and TCP-New Reno. But we can
say TCP-P is more efficient than TCP-Reno and TCP-New
Reno since it is able to solve more issues of TCP in wireless
environment.
Differentiated Classes of Service and Flow Management using An Hybrid Broker1IDES Editor
Recently, mobile networks have been overloaded
with a considerable amount of data traffic. The current paper
proposes a management service for mobile environments,
using policies and quality metrics, which ensure a better usage
of network resources with a more fine-grained management
based on flows with different classes of service and
transmission rates. This management of flows is supported
through a closed innovative control loop among a flexible
brokerage service in the network, and agents at the mobile
terminals. It also allows the terminals to make well-informed
decisions about their connections to enhance the number of
connected flows per technology and the individual service level
offered to each flow. Our results indicate that the proposed
solution optimizes the usage of available 4G network resources
among a high number of differentiated flows in several
scenarios where access technologies are extremely overloaded
whilst protecting, through a low complexity scheme, the flows
associated to users that have celebrated more expensive
contracts with their network operators.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
Implementing True Zero Cycle Branching in Scalar and Superscalar Pipelined Pr...IDES Editor
In this paper, we have proposed a novel architectural
technique which can be used to boost performance of modern
day processors. It is especially useful in certain code constructs
like small loops and try-catch blocks. The technique is aimed
at improving performance by reducing the number of
instructions that need to enter the pipeline itself. We also
demonstrate its working in a scalar pipelined soft-core
processor developed by us. Lastly, we present how a superscalar
microprocessor can take advantage of this technique and
increase its performance.
Comparative analysis of the performance of various active queue management te...IJECEIAES
This paper demonstrates the robustness of active queue management techniques to varying load, link capacity and propagation delay in a wireless environment. The performances of four standard controllers used in Transmission Control Protocol/Active Queue Management (TCP/AQM) systems were compared. The active queue management controllers were the Fixed-Parameter Proportional Integral (PI), Random Early Detection (RED), Self-Tuning Regulator (STR) and the Model Predictive Control (MPC). The robustness of the congestion control algorithm of each technique was documented by simulating the varying conditions using MATLAB® and Simulink® software. From the results obtained, the MPC controller gives the best result in terms of response time and controllability in a wireless network with varying link capacity and propagation delay. Thus, the MPC controller is the best bet when adaptive algorithms are to be employed in a wireless network environment. The MPC controller can also be recommended for heterogeneous networks where the network load cannot be estimated.
In Wireless Sensor Network (WSN), QoS (Quality of Service) in sensor application plays a very important
role. QoS based routing is required to ensure the best use of nodes in WSN. In this paper, a comparative
study of QoS based routing in Media Access Control (MAC) protocols are presented based on the traits to
solve problems like prioritization, timeliness, reliability etc. The study mainly focuses on some priority
based QoS protocols used in WSN and a comparison among them. The study reveals that among the five
mentioned protocols; QMAC, PRIMA, DB-MAC, RAP, GTS; PRIMA shows the best performance in the
category of Packet Prioritization, Scheduling Scheme, Queue Type, Energy Awareness and QoS.
A novel token based approach towards packet loss controleSAT Journals
This document summarizes a research paper that proposes a novel congestion control mechanism called Stable Token-Limited Congestion Control (STLCC). STLCC monitors inter-domain traffic rates and limits the number of tokens to control congestion and improve network performance. The authors implemented STLCC in a prototype application and found that it was effective at controlling packet loss and improving network performance compared to other congestion control methods. They concluded that STLCC can automatically measure and reduce congestion to allocate network resources stably.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
This study presents the “overview of TCP
performance on satellite communication networks”, aimed at
satellite characteristics, their effects on throughput selected link
control protocols and various method proposed for enhancing
TCP throughput on satellite networks. Literature reviews on
satellite link characteristics and their effects on TCP operation in
satellite communication networks. Different improve strategies
that have been proposed to enhance TCP data throughput on
satellite links. The choice of frame size (n in bits) and window size
(W in number of frames) used to improve data throughput on
satellite links were considered in this study. Also, the role of
sliding window flow control protocol was considered. However,
the sliding window method ensures that traffic congestion on the
networks is minimized and also, increases the TCP throughput in
satellite communication networks
Congestion control in packet switched wide area networks using a feedback modelijcses
In a complex world, where networking expands very rapidly, the network stability of flow of bandwidth
played a vital role in transmitting packets. Hence, it was imperative to find solution to the problem of
congestion especially in the follow of bandwidth stability.
Congestion in computer networking is caused by so many factors. Some of the signs are packet loss,
queuing delay resulting from overloading the buffer, faulty hardware devices, intermixing of old and new
technologies and unstable flow of bandwidth resulting from positive feedback
Performance evaluation of the IEEE 802.11n random topology WLAN with QoS appl...IJECEIAES
The IEEE 802.11n supports high data rate transmissions due its physical layer Multiple Input Multiple Output (MIMO) advanced antenna system and MAC layer enhancement features (frame aggregation and block acknowledgement). As a result this standard is very suitable for multimedia services through its Enhanced Distributed Channel Access (EDCA). This paper focuses on evaluating the Quality of Service (QoS) application on the performance of the IEEE 802.11n random topology WLAN. Three different number of nodes (3, 9 and 18) random topology with one access point are modeled and simulated by using the Riverbed OPNET 17.5 Modular to investigate the Wireless Local Area Network (WLAN) performance for different spatial streams. The result clarified the impact of QoS application and showed that its effect is best at the 18 node number topology. For a 4x4 MIMO, when QoS is applied and with respect to the no QoS application case, simulation results show a maximum improvement of 86.4%, 33.9%, 52.2% and 68.9% for throughput, delay, data drop and retransmission attempts, respectively.
A MAC PROTOCOL WITH DYNAMIC ALLOCATION OF TIME SLOTS BASED ON TRAFFIC PRIORIT...ijaia
In a wireless body area network (WBAN), wireless biomedical sensors are placed around, on, or inside the human body. Given specific requirements, WBANs can significantly improve healthcare, diagnostic monitoring, and other medical services. However, the existing standards such as IEEE 802.11 and IEEE 802.15.4 have some limitations to meet all the requirements of WBANs. Many medium access control (MAC) protocols have been studied so far, most of which are derived from the IEEE 802.15.4 superframe structure with some improvements and adjustments. However, the MAC protocols do not provide the required quality of service (QoS) for various types of traffic in a WBAN. In this paper, a traffic-aware MAC (TA-MAC) protocol for WBANs is proposed, in which time slots are dynamically allocated on the basis of traffic priority, providing the required QoS. According to the performance evaluation results, the proposed TA-MAC is better than IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of transmission time, system throughput, energy efficiency, and collision ratio.
This document reviews different criteria for designing routing protocols in mobile ad hoc networks. It discusses several qualitative and quantitative characteristics that make for an effective routing protocol, including being loop-free, distributed, fast, and power efficient. The document then classifies routing protocols based on various criteria such as whether they use pre-computed or on-demand routing, periodic or event-driven updates, flat or hierarchical network structures, and whether they establish single or multiple paths. It reviews common routing protocol types like proactive, reactive, source routing, and hop-by-hop routing. In conclusion, the document emphasizes that routing protocols are needed to dynamically find optimal paths between sources and destinations across multiple hops in mobile ad hoc networks.
This document discusses radio resource management in LTE-Advanced systems using carrier aggregation. It introduces carrier aggregation as a technique in LTE-Advanced to aggregate multiple component carriers to improve user throughput. Previous research on resource allocation with carrier aggregation did not consider delay factors and error probability, limiting quality of service. The paper proposes an improved scheduling method for carrier aggregation that considers head of line delay, packet loss probability, and delay thresholds for different data types. It aims to enhance system throughput while maintaining computational complexity. Simulation results show the proposed method outperforms previous approaches in terms of average user throughput, cell throughput, fairness, and spectral efficiency.
Performing Network Simulators of TCP with E2E Network Model over UMTS NetworksAM Publications,India
Wireless links losses result in poor TCP throughput since losses are perceived as congestion by TCP with the evolution of 3G technologies like Universal Mobile Telecommunication System (UMTS), the usage of TCP has become more popular for a reliable end-to-end (e2e) data delivery. However, TCP was initially designed for wired networks and therefore it suffers performance degradation due to the radio signal getting affected by fading, shadowing and interference. There are many strategies proposed by the research community on how to improve the performance of TCP over wireless links such as introducing link-layer retransmission, explicitly notifying the sender of network conditions or using new variants of TCP. As UMTS network coverage and availability are currently experiencing rapid growth, optimization of various internal components of its wireless network is very important. One of the optimization is the introduction of High Speed Downlink Packet Access (HSDPA). This architecture not only allows higher data rates but also more reliable data transfer by the introduction of Hybrid ARQ (HARQ). With this enhancement to the UMTS network, it becomes vital to see the performance of TCP in such a network. Therefore in this thesis, we try to evaluate two aspects of UMTS networks: first, the impact of HSDPA parameters like scheduling algorithm and RLC/MAC-hs buffer size on overall performance of TCP and second, to study the behaviour of two categories of TCP rate and flow control: loss based and delay based. Our simulation shows that delay based TCP tends to perform better than loss based TCP in our selected scenarios. The simulations are performed using the network simulator NS-2 with an e2e network model for enhanced UMTS (EURANE).
This document proposes a new cell selection and handover approach for heterogeneous LTE networks that considers additional criteria of base station capacity estimation and user speed. The proposed algorithm aims to improve network load balancing and user quality of service. It estimates base station capacity based on average resource availability over time and calculates user speed to reduce the impact of sudden speed changes on cell selection and handover decisions. Simulation results show the approach contributes to macrocell offloading, load balancing and improved user QoS.
Exponential MLWDF (EXP-MLWDF) Downlink Scheduling Algorithm Evaluated in LTE ...IJECEIAES
The document summarizes a research paper that evaluates the performance of a new downlink scheduling algorithm called Exponential Modified Largest Weighted Delay First (EXP-MLWDF) in an LTE network under high mobility and dense user scenarios. It compares the performance of EXP-MLWDF to other scheduling algorithms such as Proportional Fair (PF), Exponential Proportional Fairness (EXP/PF), Logarithm Rule (LOG-Rule), Exponential Rule (EXP-Rule) and Modified Largest Weighted Delay First (MLWDF) in terms of system throughput, delay and packet loss ratio based on simulations. The simulations showed that EXP-MLWDF satisfies quality of service requirements for real-time traffic better than the other algorithms
QOS-B ASED P ERFORMANCE E VALUATION OF C HANNEL -A WARE /QOS-A WARE S CHEDULI...csandit
Long Term Evolution (LTE) is defined by the Third G
eneration Partnership Project (3GPP)
standards as Release 8/9. The LTE supports at max 2
0 MHz channel bandwidth for a carrier.
The number of LTE users and their applications are
increasing, which increases the demand on
the system BW. A new feature of the LTE-Advanced (L
TE-A) which is defined in the 3GPP
standards as Release 10/11 is called Carrier Aggreg
ation (CA), this feature allows the network
to aggregate more carriers in-order to provide a hi
gher bandwidth. Carrier Aggregation has
three main cases: Intra-band contiguous, Intra-band
non-contiguous, Inter-band contiguous.
The main contribution of this paper was in implemen
ting the Intra-band contiguous case by
modifying the LTE-Sim-5, then evaluating the Qualit
y of Service (QoS) performance of the
Modified Largest Weighted Delay First (MLWDF), the
Exponential Rule (Exp-Rule), and the
Logarithmic Rule (Log-Rule) scheduling algorithms
This document discusses throughput performance analysis of Voice over IP (VoIP) in Long Term Evolution (LTE) networks. It begins with an introduction to LTE and the increasing demand for high-speed wireless communication. It then describes the generic frame structures used in LTE, including Type 1 and Type 2 frames for Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) respectively. Next, it covers LTE's quality of service framework and use of Real-time Transport Protocol (RTP) for audio and video transmission. Finally, it provides an overview of VoIP technology and its characteristics, such as delay requirements and use of codecs like AMR to provide constant bit rate transmission of compressed
Throughput Performance Analysis VOIP over LTEiosrjce
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The document describes a proposed unified algorithm for load balancing (LB) and handover optimization (HOO) in Long-Term Evolution (LTE) networks. The algorithm uses a Fuzzy System (FS) tuned by the Q-Learning reinforcement learning algorithm to modify handover parameters at the cell adjacency level. This aims to improve key performance indicators related to both LB and HOO. Simulation results show the proposed joint algorithm provides better performance than independent LB and HOO entities operating simultaneously. The algorithm reduces complexity for the self-organizing network coordination entity by handling LB and HOO jointly rather than as separate functions.
Improving Performance of TCP in Wireless Environment using TCP-PIDES Editor
Improving the performance of the transmission
control protocol (TCP) in wireless environment has been an
active research area. Main reason behind performance
degradation of TCP is not having ability to detect actual reason
of packet losses in wireless environment. In this paper, we are
providing a simulation results for TCP-P (TCP-Performance).
TCP-P is intelligent protocol in wireless environment which
is able to distinguish actual reasons for packet losses and
applies an appropriate solution to packet loss.
TCP-P deals with main three issues, Congestion in
network, Disconnection in network and random packet losses.
TCP-P consists of Congestion avoidance algorithm and
Disconnection detection algorithm with some changes in TCP
header part. If congestion is occurring in network then
congestion avoidance algorithm is applied. In congestion
avoidance algorithm, TCP-P calculates number of sending
packets and receiving acknowledgements and accordingly set
a sending buffer value, so that it can prevent system from
happening congestion. In disconnection detection algorithm,
TCP-P senses medium continuously to detect a happening
disconnection in network. TCP-P modifies header of TCP
packet so that loss packet can itself notify sender that it is
lost.This paper describes the design of TCP-P, and presents
results from experiments using the NS-2 network simulator.
Results from simulations show that TCP-P is 4% more
efficient than TCP-Tahoe, 5% more efficient than TCP-Vegas,
7% more efficient than TCP-Sack and equally efficient in
performance as of TCP-Reno and TCP-New Reno. But we can
say TCP-P is more efficient than TCP-Reno and TCP-New
Reno since it is able to solve more issues of TCP in wireless
environment.
Differentiated Classes of Service and Flow Management using An Hybrid Broker1IDES Editor
Recently, mobile networks have been overloaded
with a considerable amount of data traffic. The current paper
proposes a management service for mobile environments,
using policies and quality metrics, which ensure a better usage
of network resources with a more fine-grained management
based on flows with different classes of service and
transmission rates. This management of flows is supported
through a closed innovative control loop among a flexible
brokerage service in the network, and agents at the mobile
terminals. It also allows the terminals to make well-informed
decisions about their connections to enhance the number of
connected flows per technology and the individual service level
offered to each flow. Our results indicate that the proposed
solution optimizes the usage of available 4G network resources
among a high number of differentiated flows in several
scenarios where access technologies are extremely overloaded
whilst protecting, through a low complexity scheme, the flows
associated to users that have celebrated more expensive
contracts with their network operators.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
Implementing True Zero Cycle Branching in Scalar and Superscalar Pipelined Pr...IDES Editor
In this paper, we have proposed a novel architectural
technique which can be used to boost performance of modern
day processors. It is especially useful in certain code constructs
like small loops and try-catch blocks. The technique is aimed
at improving performance by reducing the number of
instructions that need to enter the pipeline itself. We also
demonstrate its working in a scalar pipelined soft-core
processor developed by us. Lastly, we present how a superscalar
microprocessor can take advantage of this technique and
increase its performance.
Comparative analysis of the performance of various active queue management te...IJECEIAES
This paper demonstrates the robustness of active queue management techniques to varying load, link capacity and propagation delay in a wireless environment. The performances of four standard controllers used in Transmission Control Protocol/Active Queue Management (TCP/AQM) systems were compared. The active queue management controllers were the Fixed-Parameter Proportional Integral (PI), Random Early Detection (RED), Self-Tuning Regulator (STR) and the Model Predictive Control (MPC). The robustness of the congestion control algorithm of each technique was documented by simulating the varying conditions using MATLAB® and Simulink® software. From the results obtained, the MPC controller gives the best result in terms of response time and controllability in a wireless network with varying link capacity and propagation delay. Thus, the MPC controller is the best bet when adaptive algorithms are to be employed in a wireless network environment. The MPC controller can also be recommended for heterogeneous networks where the network load cannot be estimated.
In Wireless Sensor Network (WSN), QoS (Quality of Service) in sensor application plays a very important
role. QoS based routing is required to ensure the best use of nodes in WSN. In this paper, a comparative
study of QoS based routing in Media Access Control (MAC) protocols are presented based on the traits to
solve problems like prioritization, timeliness, reliability etc. The study mainly focuses on some priority
based QoS protocols used in WSN and a comparison among them. The study reveals that among the five
mentioned protocols; QMAC, PRIMA, DB-MAC, RAP, GTS; PRIMA shows the best performance in the
category of Packet Prioritization, Scheduling Scheme, Queue Type, Energy Awareness and QoS.
A novel token based approach towards packet loss controleSAT Journals
This document summarizes a research paper that proposes a novel congestion control mechanism called Stable Token-Limited Congestion Control (STLCC). STLCC monitors inter-domain traffic rates and limits the number of tokens to control congestion and improve network performance. The authors implemented STLCC in a prototype application and found that it was effective at controlling packet loss and improving network performance compared to other congestion control methods. They concluded that STLCC can automatically measure and reduce congestion to allocate network resources stably.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
This study presents the “overview of TCP
performance on satellite communication networks”, aimed at
satellite characteristics, their effects on throughput selected link
control protocols and various method proposed for enhancing
TCP throughput on satellite networks. Literature reviews on
satellite link characteristics and their effects on TCP operation in
satellite communication networks. Different improve strategies
that have been proposed to enhance TCP data throughput on
satellite links. The choice of frame size (n in bits) and window size
(W in number of frames) used to improve data throughput on
satellite links were considered in this study. Also, the role of
sliding window flow control protocol was considered. However,
the sliding window method ensures that traffic congestion on the
networks is minimized and also, increases the TCP throughput in
satellite communication networks
Congestion control in packet switched wide area networks using a feedback modelijcses
In a complex world, where networking expands very rapidly, the network stability of flow of bandwidth
played a vital role in transmitting packets. Hence, it was imperative to find solution to the problem of
congestion especially in the follow of bandwidth stability.
Congestion in computer networking is caused by so many factors. Some of the signs are packet loss,
queuing delay resulting from overloading the buffer, faulty hardware devices, intermixing of old and new
technologies and unstable flow of bandwidth resulting from positive feedback
Performance evaluation of the IEEE 802.11n random topology WLAN with QoS appl...IJECEIAES
The IEEE 802.11n supports high data rate transmissions due its physical layer Multiple Input Multiple Output (MIMO) advanced antenna system and MAC layer enhancement features (frame aggregation and block acknowledgement). As a result this standard is very suitable for multimedia services through its Enhanced Distributed Channel Access (EDCA). This paper focuses on evaluating the Quality of Service (QoS) application on the performance of the IEEE 802.11n random topology WLAN. Three different number of nodes (3, 9 and 18) random topology with one access point are modeled and simulated by using the Riverbed OPNET 17.5 Modular to investigate the Wireless Local Area Network (WLAN) performance for different spatial streams. The result clarified the impact of QoS application and showed that its effect is best at the 18 node number topology. For a 4x4 MIMO, when QoS is applied and with respect to the no QoS application case, simulation results show a maximum improvement of 86.4%, 33.9%, 52.2% and 68.9% for throughput, delay, data drop and retransmission attempts, respectively.
A MAC PROTOCOL WITH DYNAMIC ALLOCATION OF TIME SLOTS BASED ON TRAFFIC PRIORIT...ijaia
In a wireless body area network (WBAN), wireless biomedical sensors are placed around, on, or inside the human body. Given specific requirements, WBANs can significantly improve healthcare, diagnostic monitoring, and other medical services. However, the existing standards such as IEEE 802.11 and IEEE 802.15.4 have some limitations to meet all the requirements of WBANs. Many medium access control (MAC) protocols have been studied so far, most of which are derived from the IEEE 802.15.4 superframe structure with some improvements and adjustments. However, the MAC protocols do not provide the required quality of service (QoS) for various types of traffic in a WBAN. In this paper, a traffic-aware MAC (TA-MAC) protocol for WBANs is proposed, in which time slots are dynamically allocated on the basis of traffic priority, providing the required QoS. According to the performance evaluation results, the proposed TA-MAC is better than IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of transmission time, system throughput, energy efficiency, and collision ratio.
This document reviews different criteria for designing routing protocols in mobile ad hoc networks. It discusses several qualitative and quantitative characteristics that make for an effective routing protocol, including being loop-free, distributed, fast, and power efficient. The document then classifies routing protocols based on various criteria such as whether they use pre-computed or on-demand routing, periodic or event-driven updates, flat or hierarchical network structures, and whether they establish single or multiple paths. It reviews common routing protocol types like proactive, reactive, source routing, and hop-by-hop routing. In conclusion, the document emphasizes that routing protocols are needed to dynamically find optimal paths between sources and destinations across multiple hops in mobile ad hoc networks.
This document discusses radio resource management in LTE-Advanced systems using carrier aggregation. It introduces carrier aggregation as a technique in LTE-Advanced to aggregate multiple component carriers to improve user throughput. Previous research on resource allocation with carrier aggregation did not consider delay factors and error probability, limiting quality of service. The paper proposes an improved scheduling method for carrier aggregation that considers head of line delay, packet loss probability, and delay thresholds for different data types. It aims to enhance system throughput while maintaining computational complexity. Simulation results show the proposed method outperforms previous approaches in terms of average user throughput, cell throughput, fairness, and spectral efficiency.
Performing Network Simulators of TCP with E2E Network Model over UMTS NetworksAM Publications,India
Wireless links losses result in poor TCP throughput since losses are perceived as congestion by TCP with the evolution of 3G technologies like Universal Mobile Telecommunication System (UMTS), the usage of TCP has become more popular for a reliable end-to-end (e2e) data delivery. However, TCP was initially designed for wired networks and therefore it suffers performance degradation due to the radio signal getting affected by fading, shadowing and interference. There are many strategies proposed by the research community on how to improve the performance of TCP over wireless links such as introducing link-layer retransmission, explicitly notifying the sender of network conditions or using new variants of TCP. As UMTS network coverage and availability are currently experiencing rapid growth, optimization of various internal components of its wireless network is very important. One of the optimization is the introduction of High Speed Downlink Packet Access (HSDPA). This architecture not only allows higher data rates but also more reliable data transfer by the introduction of Hybrid ARQ (HARQ). With this enhancement to the UMTS network, it becomes vital to see the performance of TCP in such a network. Therefore in this thesis, we try to evaluate two aspects of UMTS networks: first, the impact of HSDPA parameters like scheduling algorithm and RLC/MAC-hs buffer size on overall performance of TCP and second, to study the behaviour of two categories of TCP rate and flow control: loss based and delay based. Our simulation shows that delay based TCP tends to perform better than loss based TCP in our selected scenarios. The simulations are performed using the network simulator NS-2 with an e2e network model for enhanced UMTS (EURANE).
This document proposes a new cell selection and handover approach for heterogeneous LTE networks that considers additional criteria of base station capacity estimation and user speed. The proposed algorithm aims to improve network load balancing and user quality of service. It estimates base station capacity based on average resource availability over time and calculates user speed to reduce the impact of sudden speed changes on cell selection and handover decisions. Simulation results show the approach contributes to macrocell offloading, load balancing and improved user QoS.
Exponential MLWDF (EXP-MLWDF) Downlink Scheduling Algorithm Evaluated in LTE ...IJECEIAES
The document summarizes a research paper that evaluates the performance of a new downlink scheduling algorithm called Exponential Modified Largest Weighted Delay First (EXP-MLWDF) in an LTE network under high mobility and dense user scenarios. It compares the performance of EXP-MLWDF to other scheduling algorithms such as Proportional Fair (PF), Exponential Proportional Fairness (EXP/PF), Logarithm Rule (LOG-Rule), Exponential Rule (EXP-Rule) and Modified Largest Weighted Delay First (MLWDF) in terms of system throughput, delay and packet loss ratio based on simulations. The simulations showed that EXP-MLWDF satisfies quality of service requirements for real-time traffic better than the other algorithms
QOS-B ASED P ERFORMANCE E VALUATION OF C HANNEL -A WARE /QOS-A WARE S CHEDULI...csandit
Long Term Evolution (LTE) is defined by the Third G
eneration Partnership Project (3GPP)
standards as Release 8/9. The LTE supports at max 2
0 MHz channel bandwidth for a carrier.
The number of LTE users and their applications are
increasing, which increases the demand on
the system BW. A new feature of the LTE-Advanced (L
TE-A) which is defined in the 3GPP
standards as Release 10/11 is called Carrier Aggreg
ation (CA), this feature allows the network
to aggregate more carriers in-order to provide a hi
gher bandwidth. Carrier Aggregation has
three main cases: Intra-band contiguous, Intra-band
non-contiguous, Inter-band contiguous.
The main contribution of this paper was in implemen
ting the Intra-band contiguous case by
modifying the LTE-Sim-5, then evaluating the Qualit
y of Service (QoS) performance of the
Modified Largest Weighted Delay First (MLWDF), the
Exponential Rule (Exp-Rule), and the
Logarithmic Rule (Log-Rule) scheduling algorithms
This document discusses throughput performance analysis of Voice over IP (VoIP) in Long Term Evolution (LTE) networks. It begins with an introduction to LTE and the increasing demand for high-speed wireless communication. It then describes the generic frame structures used in LTE, including Type 1 and Type 2 frames for Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) respectively. Next, it covers LTE's quality of service framework and use of Real-time Transport Protocol (RTP) for audio and video transmission. Finally, it provides an overview of VoIP technology and its characteristics, such as delay requirements and use of codecs like AMR to provide constant bit rate transmission of compressed
Throughput Performance Analysis VOIP over LTEiosrjce
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Sky X products provide performance enhancement for data transmissions over satellite networks by replacing TCP with a custom protocol called Sky X that is optimized for satellite conditions like long latency and high bit error rates. The Sky X Gateway intercepts TCP connections and converts the data to the Sky X protocol for transmission over the satellite. This solution increases web and file transfer speeds by 3 to 100 times compared to TCP over satellite. The Sky X products transparently replace TCP and do not require any client or server modifications.
Long Term Evolution (LTE) is a new cellular technology that provides significantly faster data speeds of up to 150 Mbps downstream and 50 Mbps upstream. LTE uses an all-IP network and aims to support new applications requiring high data rates like video calling. The document provides an overview of the LTE protocol stack and how data packets move through it. It describes the different layers including the MAC, RLC, and PDCP layers and how packets are scheduled, transmitted, acknowledged and retransmitted in the downlink and uplink directions. Key aspects like quality of service, mobility management, power saving modes are also summarized.
Long Term Evolution (LTE) is a cellular technology that provides significantly faster data speeds of up to 150 Mbps downstream and 50 Mbps upstream. This document provides an overview of the LTE protocol stack, tracing the path of a data packet through the layers from physical to medium access control to radio link control and packet data convergence protocol. Key aspects of LTE operation discussed include hybrid automatic repeat request for error correction, scheduling, quality of service controls, handovers between base stations, and power saving modes.
This document discusses the performance evaluation of 4G LTE-SCFDMA schemes under different channel models. It provides an overview of LTE fundamentals and specifications, including bandwidths, data rates, frame structure and resource blocks. It also explains SCFDMA, describing its advantages over OFDMA in terms of lower peak-to-average power ratio and improved power efficiency. The document evaluates SCFDMA system performance using two equalization methods (zero forcing and MMSE) and two subcarrier mapping techniques (localized and distributed) under ITU and SUI channel models. The results show better performance with localized mapping and MMSE equalization.
This document summarizes key aspects of practical LTE network design and deployment. It describes the end-to-end LTE network architecture including the evolved NodeB (eNB), Evolved Packet Core (EPC), and interfaces. It then analyzes LTE coverage and link budgets for different deployment scenarios. Dimensioning and design considerations are discussed including throughput, capacity, and quality of service (QoS). Latency is analyzed and compared to HSPA+. The document provides guidance on commercial LTE network planning and implementation.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
Macro with pico cells (hetnets) system behaviour using well known scheduling ...ijwmn
This paper demonstrates the concept of using Heterogeneous networks (HetNets) to improve Long Term Evolution (LTE) system by introducing the LTE Advance (LTE-A). The type of HetNets that has been chosen for this study is Macro with Pico cells. Comparing the system performance with and without Pico cells has clearly illustrated using three well-known scheduling algorithms (Proportional Fair PF, Maximum Largest Weighted Delay First MLWDF and Exponential/Proportional Fair EXP/PF). The system is judged based on throughput, Packet Loss Ratio PLR, delay and fairness.. A simulation platform called LTE-Sim has been used to collect the data and produce the paper’s outcomes and graphs. The results prove that adding Pico cells enhances the overall system performance. From the simulation outcomes, the overall system performance is as follows: throughput is duplicated or tripled based on the number of users, the PLR is almost quartered, the delay is nearly reduced ten times (PF case) and changed to be a half (MLWDF/EXP cases), and the fairness stays closer to value of 1. It is considered an efficient and cost effective way to increase the throughput, coverage and reduce the latency.
Features And Techniques Of The 3 Gpp Lte System Transmissio Nxntoumba
This document discusses the key features and techniques of 3GPP LTE transmission systems. It begins with an introduction to how OFDMA radio access and all-IP networks enable MIMO techniques. It then discusses how LTE aims to provide higher speeds and capacity compared to 3G networks. Key LTE techniques include OFDM, MIMO, and supporting IP connectivity between mobile nodes. LTE targets download speeds up to 100 Mbps, upload speeds up to 50 Mbps, and higher spectral efficiency than HSPA to enable more cost-effective broadband services for mobile operators.
VEGAS: Better Performance than other TCP Congestion Control Algorithms on MANETsCSCJournals
The document analyzes the performance of six TCP congestion control algorithms (BIC, Cubic, Compound, Vegas, Reno, and Westwood) on mobile ad hoc networks (MANETs) using network simulator 2 (NS2). Simulation results show that the Vegas algorithm provided better and more stable throughput than the other algorithms over the entire simulation time, both with and without node mobility. While BIC achieved the highest throughput after 75 seconds, Vegas was the only algorithm that maintained almost constant throughput from the start to end of the 200 second simulations. Therefore, the document concludes that Vegas is the most suitable algorithm for MANET scenarios.
This document summarizes the physical layer frame structure used in 4G LTE and LTE-Advanced downlink transmissions. It describes how the LTE system toolbox in MATLAB can be used to generate physical signals and channels, and map them to resource elements in the time-frequency grid. Key aspects covered include the use of OFDM, resource block structure, and how synchronization signals, broadcast channels, control channels, and shared data channels are allocated in the frame. The document provides technical details on frame configurations and illustrates example resource grids for a subframe and radio frame.
This document discusses LTE Advanced and WiMAX2 (IEEE 802.16m) technologies and the use of relay stations to improve network performance. It aims to cost-effectively deploy relay stations in an LTE Advanced network while enhancing quality of service. The author outlines objectives to study different relay station deployment methods and techniques to minimize costs and improve metrics like throughput, delay and network load. The document also describes relay station types, operations and techniques like amplify-and-forward, decode-and-forward and compress-and-forward. The research methodology involves identifying the problem, conducting literature review, simulation-based testing and analyzing results.
Carrier Aggregation in LTE Releases3rd Generation Partnership Proj.docxannandleola
Carrier Aggregation in LTE Releases
3rd Generation Partnership Project (3GPP)
The 3GPP unites seven telecommunications standard development organizations (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC), which is an umbrella for these standards organizations, that develop protocols for mobile telecommunication. The 3GPP organizes its work into three different streams: Radio Access Networks, Services and Systems Aspects, and Core Network and Terminals, which provide a complete system description for mobile telecommunications. It was established in December 1998 with the goal of developing a specification for a 3G mobile phone system based on the 2G GSM system, within the scope of the International Telecommunication Union's.LTE and LTE-A
The Long-Term Evolution (LTE) is an emerging technology, which is standardized by the 3GPP and evolving to meet the International Mobile Telecommunication Advanced (IMT-Advanced) requirements named as LTE-Advanced. The main goal of LTE is to provide a high data rate, low latency and packet optimized radio access technology supporting flexible bandwidth deployments. The network architecture of LTE has been designed with the goal to support packet-switched traffic with seamless mobility and great quality of service.
LTE is a standard for wireless broadband communication for mobile devices and data terminals. LTE is based on the GSM/EDGE and UMTS/HSPA technologies. LTE increases the capacity and speed of wireless mobile communication by using a different radio interface and other core network improvements. LTE uses different frequencies and bands in different countries. LTE is commonly marketed as 4G LTE & Advance 4G. LTE is also commonly known as 3.95G. LTE-Advanced or LTE-A is a major enhancement of the LTE standard. LTE-A uses several techniques and technologies (hardware and software) to meet higher network-performance standards. The technique of this standard which we are using in our work is following.
· Increased peak data rate for DL/UL
· Improved performance at cell edges.
· Carrier Aggregation (CA), the enhanced use of multi-antenna techniques.
· Support for Relay Nodes, LTE Femtocell and macro cell.
Based on the requirements and observations, the 3GPP has identified carrier aggregation (CA) as major feature for achieving improved data rate. It is a worth noting that BW aggregation basic concept has been used in 3G. Similarly, there are options in High Speed Packet Access (HSPA) evaluation to aggregate up to four carriers for downlinks, up to two carriers for uplink and have consider both the carriers contiguous. In release 8/9 of 3GPP LTE different carrier BW of 1.4, 3, 5, 10, 15 and 20 MHz being used that provide support for several deployment plus spectrum plans. Succeeding the desires of 100 MHz BW of system, Release 10 of 3GPP LTE has presented CA one of the foremost important structure of LTE-Advanced to balance the bandwidth a far 20 MHz. CA Release 10 described up to 100 MHz system bandwidth can.
Recital Study of Various Congestion Control Protocols in wireless networkiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document discusses and compares several congestion control protocols for wireless networks, including TCP, RCP, and RCP+. It implemented an enhanced version of RCP+ in the NS-2 simulator. Simulation results showed that the proposed approach achieved higher throughput and packet delivery ratio than TCP and RCP+ in a wireless network with 10-50 nodes, with performance degrading as the number of nodes increased beyond 20 due to increased congestion. The paper analyzes the mechanisms and equations of each protocol and argues the proposed approach combines benefits of improved AIMD and RCP+ to address their individual shortcomings.
PERFORMANCE COMPARISON OF PACKET SCHEDULING ALGORITHMS FOR VIDEO TRAFFIC IN L...ijmnct
In this paper we have studied downlink packet scheduling algorithms proposed for LTE cellular networks.
The study emphasize on three most promising scheduling algorithms such as: FLS, EXP rule and LOG rule.
The performance of these three algorithms is conducted over video traffic in a vehicular environment using
LTE-Sim simulator. The simulation was setup with varying number of users from 10 - 60 in fixed bounded
regions of 1 km radius. The main goal this study is to provide results that will help in the design process of
packet scheduler for LTE cellular networks, aiming to get better overall performance users. Simulation
results show that, the FLS scheme outperforms in terms of average system throughput, average packet
delay, PLR; and with a satisfactory level of fairness index.
LTE describes standardization work by 3GPP to define a new high-speed radio access method for mobile communications systems. Key features of LTE include significantly higher data rates of up to 300 Mbps downlink and 75 Mbps uplink, lower latency, flexible spectrum usage, and an evolution to an all-IP core network. LTE will enable rich new mobile broadband services like high-quality video streaming and sharing, as well as applications in areas like machine-to-machine communication.
The important goal of this thesis is represented as demonstrating a self-organising based process for current versions of heterogeneous LTE-Advanced networks to simultaneously improve both quality of service and ability. The main index terms of this research could be exhibited as: SON; LTE-A, HetNets; Femtocell; Interference, Multi-Layer; Handover, Access Control; Power Control, eICIC. The self-organizing method of this research is described as the primary goal, to be got through the following targets: ThesisScientist.com
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THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...indexPub
The recent surge in pro-Palestine student activism has prompted significant responses from universities, ranging from negotiations and divestment commitments to increased transparency about investments in companies supporting the war on Gaza. This activism has led to the cessation of student encampments but also highlighted the substantial sacrifices made by students, including academic disruptions and personal risks. The primary drivers of these protests are poor university administration, lack of transparency, and inadequate communication between officials and students. This study examines the profound emotional, psychological, and professional impacts on students engaged in pro-Palestine protests, focusing on Generation Z's (Gen-Z) activism dynamics. This paper explores the significant sacrifices made by these students and even the professors supporting the pro-Palestine movement, with a focus on recent global movements. Through an in-depth analysis of printed and electronic media, the study examines the impacts of these sacrifices on the academic and personal lives of those involved. The paper highlights examples from various universities, demonstrating student activism's long-term and short-term effects, including disciplinary actions, social backlash, and career implications. The researchers also explore the broader implications of student sacrifices. The findings reveal that these sacrifices are driven by a profound commitment to justice and human rights, and are influenced by the increasing availability of information, peer interactions, and personal convictions. The study also discusses the broader implications of this activism, comparing it to historical precedents and assessing its potential to influence policy and public opinion. The emotional and psychological toll on student activists is significant, but their sense of purpose and community support mitigates some of these challenges. However, the researchers call for acknowledging the broader Impact of these sacrifices on the future global movement of FreePalestine.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
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1 improvement of tcp congestion window over lte
1. ISSN : 2278 – 1021
International Journal of Advanced Research in Computer and Communication Engineering
Vol. 1, Issue 4, June 2012
Improvement of TCP Congestion Window overLTEAdvanced Networks
Ghassan A. Abed1, Mahamod Ismail2, Kasmiran Jumari3
1,2,3
Faculty of Engineering and Built Environment, The National University of Malaysia
ABSTRACT—Long Term Evolution Advanced (LTE-Advanced) network is the continuation of 3GPP-LTE (3GPP: 3rd Generation
Partnership Project) and it targets to advanced develop of the requirements of LTE in terms of throughput and coverage. Then, LTEAdvanced is not new as a radio access technology, but it’s an evolution of LTE to enhance the performance. The direct employment of the
existing protocols cannot achieve the requirements of LTE-Advanced due to the large-bandwidth and low-latency links used in this
network. Therefore, an enhanced congestion control mechanism is proposed in this article to improve the performance of Transmission
Control Protocol (TCP) over LTE-Advanced. The proposed algorithm used a new mechanism based on the available bandwidth of the
connection to detect the capacity of network path in order to improve the congestion avoidance mechanism. The work in this paper based
on using Network Simulator 2 (NS-2) to model the traffics of LTE-Advanced and tests the proposed mechanism.
Keywords—TCP;congestion avoidance, congestion control; LTE; LTE-Advanced; NS-2
I. INTRODUCTION
LTE-Advanced must be compatible backwards in the
sense that it should be possible to deploy LTE-Advanced
spectrum that occupied LTE with no effect on existing
plants of LTE, to include the possibility for data rates [1].
However, more important than the peak data rates is the
possibility of providing high data rates over the greater part
of the cell. While LTE Rel.8 supports peak data rates
exceeding 300 Mbps in the downlink (DL) and 75Mbps in
the uplink (UL), LTE is expected to provide in Rel.10 up to
1Gbps in DL and 500 in UL [2]. Also, it will be extended
carrier bandwidths up to 100 MHz for LTE-Advanced, while
the limited bandwidth in the Far Rel.8 (LTE) is only 20
MHz. Furthermore, the increased spectral efficiency even in
30 bps/Hz in DL and 15-bit / Hz in the UL side by side with
the ability to improve the edge of the cell, the user and
control plane disappearances, and urged on the user
experience more homogeneous over the area of the cell. The
specification of the Evolved Universal Terrestrial Radio
Access (E-UTRA) is on-going within 3GPP. 3GPP has
started LTE of 3G since 2004, whose objectives include
reduced latency, higher user data rates, improved system
capacity and coverage, and reduced overall cost for the
operator [3]. LTE-Advanced systems under developments
now, and TCP protocol is the most widely used protocol for
wired and wireless systems, although TCP was not
originally designed for real time applications and not for
wireless networks. Then we need to develop new TCP
versions, or at least choose a suitable TCP variant for each
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new network to be more efficient and more reliable with this
network. For the first time to the congestion control
mechanisms in early 1980 and was designed primarily to
stop the collapse with traffic congestion typical of that era.
In recent years, increased volume of traffic generated by
real-time applications, a high proportion of large transport
package and congestion control in more often than not opt
for these types of applications. By this reason, the systems
can fit into the new system is uncontrolled, so much the
overall productivity of the oscillating flow and one which, in
turn, can result in poor application performance. Apart from
concerns about the network level, and those types of
applications a lot of care, end-to-end delay in the speed and
smooth congestion control, this does not fit the traditional
schemes. In this research, we will investigate improving the
performance of the new congestion control algorithm,
developed to be able to transfer high rate of packet over
large bandwidth low-latency platform, such as Advanced
LTE.When using TCP over the cellular infrastructure, and
the result is that both times of end-to-end production and use
of radio link is very weak. This is because the dynamic
characteristics of TCP and wireless connections do not fit
well together [4]. TCP limits transmission rate by
controlling the send congestion window size, which is the
number of packets that can be transmitted in the flow.
Generally, the time between the submission and receipt of
ACK packet is Round-Trip Time (RTT). TCP sender can
send up to the congestion window size of data packets
during one RTT. Once send the TCP window size of data
packets, it can send the new data packet only after it is
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reached to some of the ACKs to the sender. Therefore, the
average rate of more than TCP RTT is almost the size of the
window divided by the RTT [5]. The most important
concept in TCP congestion control is the congestion window,
where the window is the amount of data that have been sent,
but which have not yet received any confession. Congestion
window constant means that the broadcast packet and a new
one for each ACK that is received while the control is in the
rate of transmission indirectly by adjusting the size of the
congestion. Been documented standard way to do so in
RFC2581 [6], usually referred to as TCP Reno. The other
common TCP versions are Newneno [7] and TCP with
selective ACK (Sack) [8,9].
In order to improve TCP performance, many TCP
variants, which mainly differ with each other on the
functions of congestion control, have been proposed.
Currently, there are six TCP source variants; Tahoe, Reno,
Newreno, Fack, Sack, and Vegas, adding many other
extended variants. Each variant has been a private
congestion control algorithm or developed a previous
algorithm, to be efficient and reliable with a new end-to-end
application.
II. ARCHITECTURE OF LTE-ADVANCED NETWORK
Fig.1 LTE-Advanced E-UTRAN and EPC architecture
Each eNodeB are connected to the MME/SAE Gateway
via S1 interface where X2 interface is interconnecting the
eNodeBs (or eNBs). The X2 interface is used also on U-plane
for temporary user downlink data. The main functions of the
eNodeB are:
Developed by 3GPP, LTE is the leading Orthogonal
Frequency-Division Multiple Access (OFDMA) wireless
mobile broadband technology. LTE offers high spectral
efficiency, low latency and high peak data rates. LTE/LTEAdvanced leverages the economies of scale of 3G, as well as
the ecosystem of infrastructure and devices vendors to
provide the highest performance in a cost effective manner
[10]. The notion of LTE technology depends on the
understood that it improves system performance in terms of
data rate, throughput, latency, coverage and cost. LTE offers a
pure packets assigned architecture, with viability of the
movement management. The latest step being studied and
developed in 3GPP is an evolution of 3G into an evolved
radio access referred to as the LTE and an evolved packet
access core network in the System Architecture Evolution
(SAE) [11].
Radio resource management (radio bearer control,
radio admission and connection mobility control,
dynamic scheduling).
Routing user plane data towards SAE Gateway.
The function of MME/SAE Gateway is to distribute the
migration of messages to eNBs; security control; encryption
of user data, switching of U-plane to support of UE mobility;
idle mode mobility handling [12]. Fig. 2 gives a graphical
overview of both protocol stacks. In the user plane, the
protocols that are included are the Packet Data Convergence
Protocol (PDCP), the Radio Link Control (RLC), Medium
Access Control (MAC), and Physical Layer (PHY) protocols.
In this section, architecture for LTE/LTE-Advanced
introduced. So, the architecture which is considered for 3GPP
is shown in Fig. 1. E-UTRAN architecture based on, eNodeB
which acts as a base station, and called E-UTRAN Node B.
MME represents the Mobility Management Entity. S-GW is a
serving gateway, and last, P-GW is a PDN (Packet Data
Network) Gateway.
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Fig.2 Protocol stack
The control plane stack additionally includes the Radio
Resource Control (RRC) protocols. The main functionalities
carried out in each layer are summarized in the following [13,
14]:
NAS (Non-Access Stratum) – Connection/session
management between UE and the core network.
RRC (Radio Resource Control) – Broadcast system
information related to Non-Access Stratum (NAS) and
Access Stratum (AS).
PDCP (Packet Data Convergence Protocol) – Header
compression and Duplicate detection.
RLC (Radio Link Control) – Error correction through
Automatic Repeat request (ARQ).
MAC (Medium Access Control) – Multiplexing/ Demultiplexing of RLC Packet Data Units (PDUs).
LTE, 3GPP is also defining IP-based, flat network
architecture. This architecture is defined as part of the (SAE)
effort. The LTE/SAE architecture and concepts have been
designed for efficient support of mass-market usage of any IPbased service. An example of such basic application data
which can be configured automatically via the S1 SETUP
procedure is the tracking area identities. These identities are
very important for the system operation because the tracking
areas correspond to the zones, in which UEs are paged, and
their mapping to eNBs must remain consistent between the
E-UTRAN and the EPC. Thus, once all the tracking area
identities which are to be broadcast over the radio interface
[15].
III. PROPOSED CONGESTION AVOIDANCE
Primary role, to control congestion, is adjust the window
of data transmission at sender side in such a way that is
preventing buffer overflow in the recipient, but also in the
intermediate routers. To achieve this, TCP used another
variable to control the congestion window. Congestion control
represents a number of segments of appreciation that can be
injected in the network without causing congestion. The
challenge is to take advantage of the available space in the
store network routers. Routers do not participate in the TCP
layer and the chip cannot be used to adjust the TCP ACK
frame. To resolve this problem, TCP assumes network
congestion as the retransmission timer expires, and that it
interacts with the network congestion by adjusting the
congestion window using two algorithms, slow start and
congestion avoidance, as shown in the Fig. 3.In the slow start
phase, and when the connection is established, is first set the
value of cwnd to one and then each received ACK value is
updated to: cwnd= cwnd+1 which means doubling the cwnd
per RTT.
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Fig.3 TCP Slow-Start and Congestion Avoidance
The rapid growth of cwnd continues until the packet loss
was observed, causing the value of slow-start threshold
(ssthresh) is updated to: ssthresh=cwnd/2. After losing the
packet, the connection starts from slow start again by set
cwnd=1, and is increase exponentially until the window is
equal to ssthresh, the estimate of available bandwidth in the
network. At this point, in goes to the congestion avoidance
phase, where the value of cwnd is less aggressive with the
pattern: cwnd=cwnd+1/cwnd, which implies a linear rather
than exponential growth. And will continue to increase until
the written disclosure of packet loss. The new mechanism
proposed in this article introduces new congestion avoidance
algorithm by estimate the predictable throughput with the
prospect of higher productivity, regardless of the level of
network congestion. The new algorithm depends on using the
available capacity on the network links to detect the
increasing or decreasing the size of the congestion window to
obtain an adaptive congestion avoidance mechanism. The
evaluation and representation of the new algorithm performed
using NS-2 to analyse the performance of the proposed
mechanism over many experiments. Certainly, the proposed
algorithm provided an increment in network path about 2030%, and that allows to growth the bottleneck capacity too,
even the network suffer from congestion.In proposed
mechanism, we used classic exponential increment to in
slow-start phase. Where congestion window cwnd less than
slow-start threshold ssthresh and the window size increases
by one, as explained in Eq. (1):
if (cwnd<ssthresh)
Then cwnd=cwnd+1
(1)
TCP sender updates congestion window size cwnd in the
congestion avoidance phase according to the following
equation when it receives an ACK packet from receiver TCP
as shown in Eq. (2):
cwnd=cwnd+(f/cwnd)
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(2)
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Where f is control parameter. From this equation, we
expect that the congestion window size increases by
fsegments in every RTT. The main function of the proposed
mechanism is to regulate f dynamically and adaptively,
while the original TCP Reno uses fixed value of f=1. In the
rest of this subsection, we explain how to change f to the
network condition and the current throughput of the TCP
connection.The classic algorithm’s code is as follows:
previous cwnd value multiplied by the exponent cwnd to the
k parameter in binominal control as shown in Eq. (4):
f=f/(cwnd*pow(cwnd,k_parameter))
(4)
cwmd_ = cwnd_ + ( f / cwnd_)
This means, the proposed mechanism steals
bandwidth from competing flows in the network in order to
achieve the bandwidth required by the upper-layer
application. In summary, the proposed mechanism updates f
using the following formula when TCP sender receives a
new ACK:
where:
f=wnd_const_*ssthresh_/cwnd_
*pow(cwnd_, k_parameter_);
cwnd_ : is the real cwnd variable in NS-2.
ssthresh_: is the real ssthresh variable in NS-2.
f : control parameter, and f=1 in Reno.
cwmd_ = cwnd_ + ( f/ cwnd_);
IV. MODELLING AND SIMULATION OF LTE-ADVANCED
In proposed mechanism, we need to update f for equation
(2) when the sender of TCP receives a new ACK. By this
ACK-based mechanism, the proposed mechanism can
accommodate the fluctuation of RTTs of the network path.
In fact we depend on four main parameters to updates f
values every RTT. These parameters illustrated below:
ssthresh: slow-start threshold of network path.
cwnd: the last value of cwnd.
wnd_const: packets per RTT.
K_parameter: k parameter in binomial controls.
By using these parameters for determining f, the
degree of increase of congestion window size becomes too
large when the current throughput of a TCP connection is far
below the target throughput. The large values of f will cause
bursty packet losses in the network and resulting in
performance degradation due to retransmission timeouts. On
the other hand, when the network has sufficient residual
bandwidth, the degree of increase of the congestion window
size becomes smaller than one. Therefore, we limit the
maximum and minimum values of f. For that, every RTT,
the new value of f becomes:
f=ssthresh*wnd_const(3)
In Eq. (3), f will equal the available bandwidth; this
will adjust the sending interval of the data packets according
to the available bandwidth of the network path. Next, when
the proposed formula in Eq. (3) has obtained a larger
throughput as explained, we need to minimize the value of f
to avoiding packets losses. The control of this problem by
divide the last value of f obtained from Eq. (3) by the
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The traffic model designed for an LTE/LTE-Advanced
system is generally more complex in nature than the traffic
model used for a GSM or 3G system. In an LTE-Advanced
system, the Mobility Management Entity (MME) and the
System Architecture Evolution (SAE) gateway communicate
with the eNB by way of an S1 interface. For traffic transport,
the S1 interface employs the hub-and-spoke model, which is
similar to the traffic model of Iub interface in a 3G system.
An X2 interface is used between eNBs in the LTE system to
ease the SAE gateway traffic load caused by frequent
handover. However, using this type of interface greatly
increases the complexity of the traffic model for backhaul
networks, as shown in Fig. 1. Theoretically, each eNB must
have a direct physical or logical link with its neighbouring
eNBs in order to support X2 interfaces, if connectionoriented technology is used.Before describing the model
requirements and configuration, and because we used the
network simulator, NS-2, we must explain, NS-2 is a
discrete event simulator targeted at networking research.
NS-2 provides substantial support for simulation of TCP,
routing, and multicast protocols over wired and wireless
(local and satellite) networks [16]. In NS-2 simulation, all
the data in the network is available, thus the performance of
the network can be easily analysed. NS-2 is free and open
source code and suitable to build system level simulation, so
it is deployed to simulate LTE/LTE-Advanced, or any other
network. In our research, we used NS-2 version 2.34, and
this version, can installed over Windows XP with using
Cygwin, where Cygwin provides a Linux-like environment
under Windows. Fig. 4, shows the proposed model, for this
research, it consist from one server for serving FTP and
HTTP, and to provide a source connection for the TCP link
over the topology.
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TABLE I
SIMULATION PARAMETERS
Parameter
Propagation Delay of all links
Bandwidth eNB-eNB
Bandwidth eNB-aGW
Bandwidth aGW-Server
Bandwidth UE-eNB
Packet Size
Window size
Simulation Time
Fig.4 Proposed Topology
The router aGW, connected to the server with duplex
link (two ways) and Drop Tail, with bandwidth of 1Gbps,
and propagation delay of 5 msec. The main job of aGW
router is to control the flow rate of the streaming data from
server to eNB-1, and eNB-2. These two nodes are
responsible for buffering the data packets to User Equipment
UEs. Each eNB, connected to the corresponding aGW
through wired simplex link (one way) of 10 Mbps
bandwidth and 5 msec delay [17,18]. The other main
parameters of proposed LTE-Advanced topology illustrated
in Table I, and we can note that all link kept for one
propagation delay of 5 msec, and the maximum packet size
of TCP was set to 1500 Byte, with minimum window size of
48 Kbytes.Fig. 5 represents the real topology animation
created by NS-2 network simulator. The wireless nodes
(UEs) linked to the corresponding eNB, through wireless
link as a mobile nodes, where the nodes 4,5,6, and 7
connected to eNB-1, and the nodes 8,9,10, and 11 connected
to eNB-2. Really, the UE nodes not have full mobility
features, because they not move yet, and if we support the
movement of these nodes we must add a handover scenario
to the topology, and this is not our goal in this research.
Fig.5 Screenshot of Proposed Network Model
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Value
5 msec
10 Mbps
10 Mbps
1 Gbps
2 Mbps
1500 Byte
48 Kbytes
30 sec
The evaluation of new congestion control mechanism,
already added to a new TCP. This new TCP have the same
parameters and specification of other TCP source variants;
only the congestion control algorithm changed. In first time,
when this new TCP developed, and before supported by new
congestion control mechanism, it was tested with constant
function of congestion window; cwnd=h, where his a
constant value such as 40 (packets). This permit to
developers to testing the other main functions of the new
TCP before adding new congestion control mechanism, and
evaluation of the behaviour of congestion window when it
have a constant value.
V. RESULTS DISCUSSION AND PERFORMANCE
EVALUATION
Firstly, we check whether new mechanism can be
effective to the bandwidth available in network path. In
these experiments, we performed the data transfer using the
new TCP by change the bottleneck bandwidth of the
network and keep all other parameters. As shown in Fig. 6,
we used a bandwidth of 100 Mbps and test the behaviour of
cwnd of new TCP and compared it with TCP Reno.
Fig.6 cwnd Behaviour of New Mechanism and Reno (BW=100Mbps)
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Fig.8 cwnd Behaviour of New Mechanism and Reno (BW=500 Mbps)
Fig.7 cwnd Behaviour of New Mechanism and Reno (BW=200 Mbps )
The measurement results of cwnd during the experiment
explain that the congestion window of new TCP performed
well comparing with Reno congestion window, so the
clocking of new TCP is also better than Reno clocking; in
addition we have a smooth slow-start phase like Reno.
In Fig. 7, we can notes the large increment in cwnd
between new TCP and Reno, and this difference because
that we increased the bandwidth from 100Mbps in firs
experiment (Fig. 6) to 200 Mbps. This increment permit to
the new mechanism to open cwnd reaches to 75 packets
while Reno kept the same packet level in two experiments of
less than 65 packets. The reason beyond to the difference in
mechanism used in Reno and new TCP, as we explained that
because Reno used f=1, while new TCP estimates the
available capacity of network path.
The performance variation of two mechanisms appear
clearly in next test, when we used a bandwidth of 500 Mbps
as shown in Fig. 9. This leads to get a cwnd exceeded 80
packets provided by new TCP, with constant window size in
Reno. Furthermore, Fig. 8 shows that the available
bandwidth will gives a throughput of cross traffic. That is,
TCP Reno cannot be used for background data transfer. This
means that the new TCP will increase the cwnd in same time
that it will not decrease the throughput of the co-existing
foreground traffic. Additionally, Figures, 6,7, and 8, shows
that the cwnd of new TCP is closest to the available
bandwidth. Therefore, the new mechanism can utilize the
available bandwidth better than Reno. These results clearly
show the proposed mechanism which utilize the available
bandwidth information obtained by the new formula,
performs well in the experimental network environment.
These three experiments shows that the new mechanism
really related with the available bandwidth and this concept
will permit to use it in a full traffic model of LTE-Advanced
system where the bottleneck of network reaches to 1Gbps.
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For this reason and from previous experiments, it is not
efficient to use Reno or any other classic TCP variants over
high bandwidth networks like LTE and LTE-Advanced
because of the limited performance of congestion control for
these variants and that is the main reason to develop new
mechanisms has more efficiency. Next, and after we ensured
that new mechanism be ready to work over high bandwidthlow latency links, we demonstrate the performance of the
proposed mechanism over model described in Section 4. In
the simulation, we establish multiple wireless nodes
connected to base stations eNB1 and eNB2. This setting
means that the new TCP will transfer data from USs to
Server through network path with network bottleneck of
1Gbps as a bandwidth and 5 msec as a propagation delay.
Here, the new TCP will detect the current information on the
available bandwidth and the physical capacity of the
network path. This assumption is necessary in order to focus
on evaluating the algorithm described before. Fig. 9 shows
the cwnd behaviour in which the proposed mechanism can
obtained and shows that the original TCP Reno have about
of a half cwnd compared with cwnd obtained from new
mechanism.
Fig.9 cwnd Behaviour of New Mechanism and Reno(1Gbps Bandwidth)
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works well in actual LTE-Advanced networks. The
performance of the proposed mechanism is highly dependent
on the estimation results of the available bandwidth given by
the last status of network path.
Fig.10cwnd Behaviour of New Mechanism and Six TCP Variants
(BW=1Gbps)
The new mechanism gave about 125 packets as a
maximum congestion point, but Reno kept the same
previous value of 65 packets.On the other hand, the new
TCP gave a performance speed more than twice that
obtained from Reno, where everyone complete cycle clock
of cwnd in Reno, we obtained more than two cycles in new
TCP. That mean we will send a more than double amount of
packets in new mechanism. Finally, and for more accuracy,
we performed more experiment with other five TCP variants,
Newreno, Tahoe, Sack, Fack, and Vegas to achieving the
full requirement to depend the new TCP as a new
mechanism that support data transfer in LTE-Advanced
systems with high performance and with more efficiency
and reliability form other classic TCP variants, as shown in
Fig. 10.
VII.
FUTURE WORK
We will evaluate the performance of the proposed
mechanism in other actual high speed network environments.
In addition, we will test the behaviour of the congestion
window when the UEs nodes have a full mobility features
and evaluate the performance with some simple handover
scenarios when these nodes move from one eNB to another.
ACKNOWLEDGMENT
This study is sponsored by UniversitiKebangsaan
Malaysia (UKM) through the university research grant
OUP-2012-182.
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VI. CONCLUSION
In this paper, the authors focused on developing enhanced
TCP congestion control with new methodology to work over
LTE and LTE-Advanced systems. The new proposed
mechanism modifies the degree of increase of congestion
window size of a TCP connection in the congestion
avoidance phase by using the information of the available
bandwidth of the network path. Through simulation
experiments, we demonstrated that proposed mechanism
over traffic model of LTE-Advanced system and from
results obtained that new mechanism achieve the required
cwnd with high probability, even when there is no residual
bandwidth on network path. We also reported that the
extended mechanism performs efficiently to provide the
required widow size for Large-Bandwidth and Low-Latency
networks. In addition, we implemented the proposed
mechanism on a NS-2 simulator and support it by new TCP
and confirmed from the implementation that the new TCP
Copyright to IJARCCE
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Biography
Ghassan A. Abed received his B.Sc. and
M.Sc. degree in Computer Engineering
from University of Technology, Baghdad,
Iraq, in 1996 and 2003 respectively. He
was Head of Transmitters and Receivers
Dept. in Microwave Research Centre in
Ministry of Sciences and Technology,
Iraq. Currently, he is PhD candidate in
National University of Malaysia (UKM), Selangor, Malaysia.
He is working in Mobile and Computer Wireless Networks
and his research interests include developing new TCP
mechanisms to improve performance of TCP over 4G
systems and develop new high-speed protocols for highspeed and challenge networks.
Copyright to IJARCCE
Prof. Dr.Mahamod Ismail joined the
Department of Electrical, Electronics and
System
Engineering,
Faculty
of
Engineering and Built Environment,
UniversitiKebangsaan Malaysia (UKM) in
1985 and currently he is a Professor in
Communication Engineering. He received
the B.Sc. degree in Electrical and Electronics from
University of Strathclyde, U.K. in 1985, the M.Sc. degree in
Communication Engineering and Digital Electronics from
University of Manchester Institute of Science and
Technology (UMIST), Manchester U.K. in 1987, and the
Ph.D. from University of Bradford, U.K. in 1996. His
research
interests
include
mobile
and
satellite
communication, and wireless networking particularly on the
radio resource management for the next generation wireless
communication network. He is currently the Chair of IEEE
Malaysia Section.
Prof. Dr.KasmiranJumari received his
B.Sc. from National University Malaysia,
1976 and M.Sc. degree from University of
Aberdeen, UK, 1977. His Ph.D. received
from University of Kent, UK, 1985.
Currently he is a Professor at the
Department of Electrical, Electronic and
Systems Engineering, in National University of Malaysia
(UKM) from 2001. His research interests are in computer
network security, software engineering, computer
engineering, and image processing.
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