QoS Issues in Heterogeneous Networks Research Papers (original) (raw)

WiMAX and Wi-Fi are considered as the promising broadband access solutions for wireless MAN’s and LANs, respectively. In the recent works WiMAX is considered suitable as a backhaul service to connect multiple dispersed Wi-Fi ‘hotspots’. Hence a new integrated WiMAX/Wi-Fi architecture has been proposed in literatures. In this paper the performance of an integrated WiMAX/Wi-Fi network has been investigated by streaming a video conference application. The difference in performance between the two protocols is compared with respect to video conferencing. The Heterogeneous network was simulated in the OPNET simulator.

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- Wireless Communications, QoS Issues in Heterogeneous Networks
- by A. Molinaro
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- Distributed Computing, Multimedia, Performance, Satellite Communications

In peer-to-peer content distribution the lack of a central authority makes authentication difficult. Without authentication, adversary nodes can spoof identity and falsify messages in the overlay. This enables malicious nodes to launch man-in-the-middle or denial-of-service attacks. In this paper, we present a trust based content distribution for peer-to-peer overlay networks, which is built on the trust management scheme. The main concept is, before sending or accepting the traffic, the trust of the peer must be validated. Based on the success of data delivery and searching time, we calculate the trust index of a node. Then the aggregated trust index of the peers whose value is below the threshold value is considered as distrusted and the corresponding traffic is blocked. By simulation results we show that our proposed scheme achieves increased success ratio with reduced delay and drop.

This paper discusses the issue of how to obtain Quality of Service (QoS) for the new applications (Multimedia, VoIP, ...) over IP networks. QoS principles and parameters (Delay, jitter, ...) are discussed together with the architectures, frameworks, protocols and mechanisms being proposed for obtaining a guaranteed application support over the Internet and private IP networks.

- by Joberto S B Martins
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- QoS Issues in Heterogeneous Networks, Voip, QoS and QoE, RSVP

The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications.The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.

Next Generation Network (NGN) is envisage to integrate heterogeneous wireless systems. NGN is expected to have Quality as the major challenging issue. More specifically, NGN aims at providing guaranteed Quality of Service (QoS) and Quality of Experience (QoE) i.e. what quality a network provider can offer (or claims) & what quality user experiences. NGN user may be interested in changing its network operator or is forced to change the serving access point (AP) or base station (BS) in order to achieve a given level of QoE. Seamless transfer of user’s service from existing operator to a new operator bearing dissimilar radio access technology is called Vertical Handover (VHO). VHO decision may depend on the popular signal to noise ratio (SNR) criteria or other performance metrics like bit error rate, delay, jitter etc or combination of these metrics. Performance of candidate target network depends on the type of traffic i.e. whether conversational, streaming, interactive or background is implemented. Therefore to optimise VHO mechanism, all these metrics & traffic types should be evaluated. Paper elucidates contemporary VHO approaches i.e. hybrid ANP/ RTOPSIS & Oliver blume method. Different Interworking scenarios & NGN testbeds are prepared considering Wi-Fi, WiMAX, UMTS etc. as the candidate networks. Neuro-fuzzy based MCDM weight assignment technique is applied & overall network cost function is computed based
on Qualnet simulation. At the end of the paper investigation suggests that Blume algorithm is better than
the hybrid ANP mechanism because it is simple to implement, more efficient (40% more accurate), quickly
computed (20 times less) and more dynamic (application oriented).

A microstrip patch antenna (MPA) is an open circuited transmission line and is theoretically half a wavelength long. Transmission line theory dictates that any open circuited transmission line less than one quarter of the guided wavelength λg/4 long is capacitively reactive. The 1.57542 GHz rectangular miniaturised microstrip patch antenna (MMPA) resultant from this research is a 5 mm long, capacitively reactive open circuited transmission line, equating to approximately 1/21 of the guided wavelength λg/21. The capacitive reactive effect of the shortened patch antenna is negated by the introduction of a symmetrical pair of transverse inductive slits (TIS) along the y-axis of the conducting plane of the patch. The slits do not intrude into the dielectric. The simulation test of the MPA prototype returned −22 dB at 1.58 GHz for the forward voltage reflection co-efficient of the MMPA. The bandwidth is 16 kHz at −10dB, adequate for L1 1.57542 GHz GPS applications.

As Voice over IP (VoIP) becomes a reality, service providers will be able to offer the service to remote, over and under populated areas that currently are not or are only partially reached by available Public Switched Telephone Network (PSTN). The combination of wireless mesh networks (WMNs) with VoIP is an attractive solution for enterprise infrastructures, presenting availability and reduced cost for both consumers and service providers. The large number of clients in WMNs leads to an increased number of concurrent flows. However, only a handful of these flows reach their destination while still within the quality of service (QoS) bound for VoIP. This performance degradation can be attributed to protocol overhead, packet collision and interferences. This paper introduces VoIP over WMNs and uses a link-based packet aggregation scheme to improve VoIP performance in IEEE 802.11 based WMNs operating under distributed coordinate function (DCF). Simulation results show that the proposed aggregation scheme increases the number of supported flows while also reducing end-to-end delay, jitter, and packet loss of VoIP in WMNs.

In this paper, we examine WiMAX – based network and evaluate the performance for quality of service (QoS) using an idea of IEEE 802.16 technology. In our models, the study used a multiprocessor architecture organized by the interconnection network. OPNET Modeler is used to simulate the architecture and to calculate the performance criteria (i.e. throughput, delay and data dropped) that slightly concerned in network estimation. It is concluded that our models shorten the time quite a bit for obtaining the performance measures of an end-to-end delay as well as throughput can be used as an effective tool for this purpose.

The development and deployment of several wireless
and cellular networks mean that users will demand to be always
connected as they move around. Mobile nodes will therefore have
several interfaces and connections will be seamlessly switched
among available networks using vertical handover techniques.
Proactive handover mechanisms can be combined with the
deployment of a number of location-based systems that provide
location information to a very high degree of accuracy in different
contexts. Furthermore, this new environment will also allow
contextual information such as user profiles as well as the
availability of local services to be combined to provide optimal
communications for mobile users. The goal of this paper is
therefore to explore the development of a comprehensive framework
for achieving optimal communication in heterogeneous
wireless environments using location and contextual information
to provide efficient handover mechanisms. Using location-based
techniques, it is possible to demonstrate that the Time Before
Handover as well as the Network Dwell Time can be accurately
estimated. These techniques are dependent on accurately estimating
the handover radius. This paper investigates how location and
context awareness can be used to estimate the best handover
radius. The paper also explores how such techniques may be
integrated into the Y-Comm architecture which is being used to
explore the development of future mobile networks. Finally, the
paper highlights the use of ontological techniques as a mechanism
for specifying and prototyping such systems.

Network Mobility Basic Support (NEMO BS) protocol (RFC 3963) is an extension of Mobile IPv6. The NEMO BS embraced by IETF working group to permit any node in the portable network to be accessible to the Internet despite the fact the network itself is roaming. This protocol likewise Mobile IPv6 doesn't deliver any kind of Quality of Service (QoS) guarantees to its clients. It can barely offer the same level of services (i.e. Best-Effort) to all the users without obligation to the application's needs. This propositions a challenge to real-time applications that demand a precise level of QoS pledge. The Differentiated Services has recently come to be the most widely used QoS support technology in IP networks due to its relative simplicity and scalability benefits. This paper proposes a new scheme to provide QoS to mobile network nodes within NEMO context. The proposed scheme intends to reduce handover latency for the users of MNN as well as alleviates packet losses. The feasibility of the proposed enhancement is assessed by measuring its performance against the native NEMO BS standard protocol using NS-2 simulator. The obtained results in the simulation study have demonstrated that the proposed scheme outperforms the standard NEMO BS protocol.

— The need to improve QOS (Quality of service) for heterogeneous data cannot be ignored. OFDM (Orthogonal Frequency Division Multiplexing) provides the advantage of high spectral efficiency. OFDM has peculiarly been considered for making the wireless communication upgraded as per the high-speed data connection requirements of heterogeneous traffic. The OFDM technology for wireless connection has become the new face of upcoming transmission technology extensively used in wireless networks. It has proved its worth in Digital audio and video broadcasting i.e. in (DAB) and (DVB) respectively. LTE and IEEE 802.20 have also considered OFDM to increase their spectral efficiency and robustness of the network. In this paper, the framework and parameters of an OFDM system has been analyzed to support QoS in a wireless network. Simulation is achieved deploying MATLAB.

Quality of service (QoS) is the mechanism of the network to provide different service level to a different traffic type as business need. The main objective of this work is to improve QoS in network by reducing link load and bandwidth consumption. It uses a routing scheme that satisfies expected demand and minimized link utilization of system. It works on reliability by limited usage of bandwidth. Results are presented to demonstrate the effectiveness of system. The efficient QoS model provides better control and administration of network traffic. Solution of routing problem with help of proposed model allows providing the distribution of traffic between source-and destination-node so that delays along every path are equal.

- by Applied Engineering Letters and +1
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- Engineering, Mechanical Engineering, Industrial Engineering, QoS for Wireless Sensor Networks

Data strong networks have appeared as a new call in the field of wireless networks. To facilitate data users with the uprising need of high data transfer rate is a prime concern to the network provider community. Quality of service (Qos) in terms of network is to provide network resources and services to users so that it satisfies their needs and manages the network resources efficiently altogether. In this paper, we have studied different Qos approaches which have been applied in the past for achieving QoS for various kinds of applications. The kind of network we are using for communication changes the QoS dynamics substantially as providing Qos in a wireless network is way more intriguing, for many complexities being involved in a wireless channel. This paper surveys various Qos strategies and methods that have been implemented in past. To achieve Qos several scheduling and resource allocation schemes are devised by researchers as Network resources must be distributed in such a manner that bandwidth, power allocation, energy efficiency, and throughput is optimized. These QoS approaches have been analysed and compared on account of their methodology, advantages and disadvantages. The performance evaluation is done on all the strategies over some significant key metrics.

A Mobile Ad hoc NETwork (MANET) is a collection of wireless mobile hosts that form a temporary network
without a centralized administration or wired infrastructure. Due to the high mobility of nodes, the network
topology of MANETs changes very fast, making it more difficult to find the routes that message packets use.
Network control with Quality of Service (QoS) support is a key issue for multimedia applications in MANET.
Most of the real time applications have stringent requirements on bandwidth, delay, delay-jitter, packet loss
ratio, cost and other QoS metrics. This paper proposes a Multi-constrained QoS routing with mobility
prediction protocol. If the node has enough resources to transmit data packets, it uses the Global
Positioning System (GPS) to get the location information of the mobile nodes and selects the routing path
with the maximum Route Expiration Time (RET). A set of static and mobile agents are used to find the
multicast routes and transmit the packets. Extensive simulations have been conducted to evaluate the
performance of MC_MAODV using Network Simulator (NS-2). The simulation results show that the
proposed protocol achieves good performance in terms of improving packet delivery ratio and minimizing
end-to-end delay.

In this paper, a distributed on-demand routing protocol for Low Earth Orbit (LEO) satellite systems, named multiservice on-demand routing (MOR), is proposed and evaluated. The proposed protocol adjusts the routing procedure to the QoS requirements of different traffic classes. The performance of the MOR protocol is compared to the unique proposal for traffic class dependent routing in the literature and the good characteristics of the proposed scheme are corroborated by ample simulation experiments, where significant gains in performance are witnessed.

Similar to the Internet, connectivity in Next Generation Networks such as 4G will be IP-Based. This implies that they inherit all the security problems of the current Internet. Amongst these numerous threats, compromise and resource exhaustion threats which come in the form of Denial of Service attacks, are very common and particularly serious.
The severity of such attacks will be fuelled by the development
of heterogeneous devices which have several wireless interfaces,
as multi-homed devices will be able to send multiple connection
requests to the server and thus launch attacks over different
access networks. This paper details a new model to address
the problem of Denial of Service attacks against the current
Internet which limit the accessibility of a server based on its
operational scope such that the solution will work effectively in
heterogeneous, multi-homed environments. However, Denial of
service attacks target the system resources and degrade their
performance thus, affecting the Quality of Service’s delivery to
the subscribed users. Therefore, the proposed model suggests
dealing with security and QoS in an integrated manner by
using the concept of Quality of Security Service where security
is considered as a Quality of Service’ parameter. This paper
furthermore shows how security can be integrated into the
infrastructure of future network systems. However, in order to implement the proposed model, it is necessary to enhance
current networking infrastructure by extending current services
such as the Domain Naming Service and evolving new services
such as a Master Locator to support user mobility.

- by ibrahim tarrad
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- Computer Science, Distributed Computing, Social Networks, Mobile Ad Hoc Networks

In this paper we present a detailed review on the Trader’s Quality of Service (QoS) Specifications and the Effects on System Performance for Video-on-Demand Multimedia (MM) Applications, based on
server-fault initiated session switch. Enhanced Trader lists the resources necessary to support the application’s QoS requirements and makes them available for the Session Manager, which co-ordinates the
session switching. Our work demonstrates that all the components of distributed MM system should be involved in the QoS management process. The client’s requirements related to QoS must be adapted
to various constraints supported by the distributed MM system components: client machines, server machines and transport system. Our studies in contrast to the existing ones present a comprehensive review on the System Performance with relation to the session switching delay.

- by Eduard Babulak
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- Information Systems, Computer Science, Software Engineering, Computer Engineering

In order to increase the link capacity in telecommunication networks the bandwidth of
multiple channels can be aggregated by transmitting on them simultaneously. The latest
data-over-cable service interface specification (DOCSIS 3.0) for hybrid fiber coax networks
defines a mechanism for channel bonding at the link layer. Thus, the scheduler at the cable
modem termination system, which distributes the packets on the network, not only has to
support per-flow queuing but also has to distribute the packets to one modem over possibly
several channels.
In this article we propose two downstream multi-channel packet scheduling algorithms
designed to support scheduling amongst flows possibly using different numbers of channels.
Both algorithms are based on the deficit round robin (DRR) scheduler. The bonded
deficit round robin (BDRR) algorithm, has complexity dependent only on the number of
the channels and requires only one queue per flow. It is shown that the algorithm is a
latency-rate server and the latency is derived. Furthermore, BDRR bounds the packet reordering
and the maximum bounds on the packet delay and the reorder buffer needed at the
receiver are calculated. The paper explores also a second algorithm which has more similarities
with load balancing algorithms. It uses fully independent channel schedulers thus
avoiding the need for modification in the single channel DRR algorithm. The transmission
channel for a packet is selected upon its arrival. However, the algorithm does not bound the
latency and packet reorder for flows assigned to receive on multiple channels. Flows for
which such bound is needed should be assigned on a single channel.

- by Dessislava Nikolova
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- Engineering, Computer Science, Technology, Computer Networks
- by Glenford Mapp
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- Computer Networks, QoS Issues in Heterogeneous Networks

With the expansion of information interchanges innovation, the interest for Higher Data Rate Services, for example, interactive media, voice, and information over both wired and remote connections is likewise expanded OFDM is transmission strategy created to take care of the expanding demand for higher information rates in interchanges, which can be utilized as a part of both wired and remote situations. New strategies to enhance data rates are required to exchange the broad measure of information which existing procedures can't bolster. These strategies must have the capacity to give high Data rate, bit error rate (BER), maximum delay. In this paper, We have presented a survey of QoS in OFDM wireless networks along with resource allocation and scheduling algorithms, its impact and how this modulation scheme can be utilised to enhance the performance of data transmission in the future of wireless networks.

This paper studies the problem of opti- mal route selection in heterogeneous wireless sensor net- works. The link quality aware route selection strat- egy is proposed by integrating realistic communication model depicting the underlying dynamics of wireless links. The Rician/Rayleigh fading environments consid- ers communication channels with both dominant Line of Sight (LOS) and non-dominant LOS (NLOS) where the desired signal between two sensor nodes is represented by Rician fading channel while the interfering signals are modelled by Rayleigh fading channel. Link quality is portrayed by reception probability i.e. probability of successfully received packets over a communication link. Reception probability of Rician/Rayleigh fading channel is utilized as a metric for link quality aware route selec- tion. Rician/Rayleigh metric based performance is com- pared with conventional route selection metrics based on simplified communication models. The simulation results demonstrate that incorporating Rician/Rayleigh metric based link quality in route selection process pro-
tional ones such as shadowing and doppler effects. The dominant effect in such scenarios is characterized by Ri- cian fading which appears when there is a line of sight between transmitting and receiving nodes. The received signal is considered as a set of scattered components plus a dominant component, thus interference characteristics in heterogeneous networks are significantly different than in homogeneous networks. Different interference scenar- ios in heterogeneous networks are provided in [5] and it can be inferred that it is highly probable to have a situ- ation where the desired signal experiences line-of-sight and interfering signals experience non-line-of-sight con- ditions.
In this paper, link quality aware route selection scheme is proposed to estimate the quality of communication us- ing realistic communication links in Rician/Rayleigh fad- ing environment. This scheme uses reception probabil- ity as a metric to search for high end-to-end throughput routes. This integration of link quality and route selection is necessary to realize the realistic capacities of wireless sensor networks.
2. Related Work
The conventional wireless route selection schemes in multihop networks are based on simplified communica- tion models such as binary link model where nodes per- fectly communicate within a transmission radius [6]. The Hop Count (HC) metric is based on the concept of binary link model and is widely used in ad hoc networks [7] [8] because of its simplicity in implementation. Hop Count metric aims to minimize the number of hops on the route between source and destination nodes. Another popular approach is to use Euclidean Distance (ED) as route se- lection metric utilizing the geographic position of nodes [9]. This metric relies on disk graph models where sig- nal strength decays according to distance [10] [11][12] neglecting the fact that link quality can change drasti- cally due to fading. The route selection metrics based on simplistic communication models does not generate routes with higher throughput as it neglects the sensitiv- ity of wireless links. [13] show that variations of wire- less links in realistic environment strongly influence the performance of ad hoc wireless networks. Furthermore, [14] explained that simplistic assumptions of disk models yields unrealistic inclusions and limitations.
Recently, link quality incorporation with route selec- tion is considered to find the high quality routes. A link quality estimation based routing protocol (LQER) is pre-
vides routes with optimal end-to-end throughput.

Protection of information is an important issue in wireless networks. Major security risks occur while conducting activities at every level of business in wireless networks. In this paper, we discuss the major security risks and vulnerabilities in wireless networks and the protocols and mechanisms needed to address them. Particularly, it examines the mechanism of intrusion detection and prevention system as an optimal security solution when combined with native security scheme such as firewall. It therefore, focuses more on the design of an intrusion detection and prevention system based on secured mobile agents. Though intrusion detection and prevention systems are the most efficient in terms of securing wireless networks, there is need for them to be fortified against attacks while performing the function of securing wireless network. The implementation of an intelligent mobile agent is the based on code it executes. It is expected that the mobile agent can carry its entire implementation code to a new destination host, or on reaching a destination, the agent can determine what code is already there, and retrieve any missing code over the network. We therefore, propose a system that eliminates the core problems such as inability to detect and react to new attack in real-time, generating unreasonably large logs and inherent security vulnerabilities associated with the existing IDPSs. A system that can detect new vulnerabilities, process and filter large volumes of logs and react to intrusion in real time.

Abstract—In order for next generation networks to support effective handover procedures, there is a need for defining QoS signaling mechanisms that guarantee the provision of point- to- point as well as network level QoS. This paper proposes a QoS signaling mechanism to be implemented by the Y-Comm architecture as a potential 4G framework. The proposed mechanism requires certain level of cooperation among network elements; therefore, it proposes some functional modules/ interfaces to be run on different network entities. As showed in the paper, the proposed mechanism could be implemented in different scenarios such as initial registration and connection, and also in the case of handover.

IEEE 802.11 networks have a great role to play in supporting and deploying of the Internet of Things (IoT). The realization of IoT depends on the ability of the network to handle a massive number of stations and transmissions and to support Quality of Service (QoS). IEEE 802.11 networks enable the QoS by applying the Enhanced Distributed Channel Access (EDCA) with static parameters regardless of existing network capacity or which Access Category (AC) of QoS is already active. Our objective in this paper is to improve the efficiency of the uplink access in 802.11 networks; therefore we proposed an algorithm called QoS Categories Activeness-Aware Adaptive EDCA Algorithm (QCAAAE) which adapts Contention Window (CW) size, and Arbitration Inter-Frame Space Number (AIFSN) values depending on the number of associated Stations (STAs) and considering the presence of each AC. For different traffic scenarios, the simulation results confirm the outperformance of the proposed algorithm in terms of throughput (increased on average 23%) and retransmission attempts rate (decreased on average 47%) considering acceptable delay for sensitive delay services.

- by Ramesh Babu
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- QoS Issues in Heterogeneous Networks, VANETs, K Ramesh Babu

Fixed and wireless networks are increasingly converging towards common connectivity with IP-based core networks. Providing effective end-to-end resource and QoS management in such complex heterogeneous converged network scenarios requires unified, adaptive and scalable solutions to integrate and co-ordinate diverse QoS mechanisms of different access technologies with IP-based QoS. Policy-Based Network Management (PBNM) is one approach that could be employed to address this challenge. Hence, a policy-based framework for end-to-end QoS management in converged networks, CNQF (Converged Networks QoS Management Framework) has been proposed within our project. In this paper, the CNQF architecture, a Java implementation of its prototype and experimental validation of key elements are discussed. We then present a fuzzy-based CNQF resource management approach and study the performance of our implementation with real traffic flows on an experimental testbed. The results demonstrate the efficacy of our resource-adaptive approach for practical PBNM systems.

LTE Network is a high speed Network but as compare with other Networks there are places in Network where there is less coverage or no coverage. Therefore to provide services in those areas, there is need of a technology which can fill the gap. This is done with the help of
Femtocells. A Femtocell use a very low power of about 0.1
watt but as the number of Femtocells in an area increases its
transmission power also increases. We know that cellular
network are based on radio radiation and Femtocells are
deployed very near to human environment. Therefore, it is
very important to take special care while deploying
Femtoells.

- by F.-N. Pavlidou
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- Distributed Computing, Routing, Satellite Communications, Routing and Switching

In this paper, a distributed on-demand routing protocol for Low Earth Orbit (LEO) satellite systems, named multiservice on-demand routing (MOR), is proposed and evaluated. The proposed protocol adjusts the routing procedure to the QoS requirements of different trafﬁc classes. The performance of the MOR protocol is compared to the unique proposal for trafﬁc class dependent routing in the literature and

- by F.-N. Pavlidou
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- Distributed Computing, Routing, Satellite Communications, Routing and Switching
- by Farnaz Farid
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- Distributed Computing, Fuzzy Logic, Computer Networks, Fuzzy set theory

In the component-based software development, the selection step is very important. It consists of searching and selecting appropriate software components from a set of candidate components in order to satisfy the developer-specific requirements. In the selection process, both functional and non-functional requirements are generally considered. In this paper, we focus only on the QoS, a subset of non-functional characteristics, in order to determine the best components for selection. The component selection based on the QoS is a hard task due to the QoS descriptions heterogeneity. Thus, we propose a QoS ontology which provides a formal, a common and an explicit description of the software components QoS. We use this ontology in order to semantically select relevant components based on the QoS specified by the developer. Our selection process is performed in two steps: (1) a QoS matching process that uses the relations between QoS concepts to pre-select candidate components. Each candidate component is matched against the developer's request and (2) a component ranking process that uses the QoS values to determine the best components for selection from the pre-selected components. The algorithms of QoS matching and component ranking are then presented and experimented in the domain of multimedia components.

- by Denis Gabos and +1
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- QoS parameters (Mobile Ad Hoc Networks), Convergence, QoS Issues in Heterogeneous Networks, Mobile telecommunication

Abstract Enterprises nowadays are approaching towards an all IP paradigm by subscribing to different access technology links from several service providers for reliability and redundancy while providing good Quality of Service (QoS). Global System for Mobile Communications (GSM) to Voice over IP (GSM-2-VoIP) convergence and vice-versa is a step forward towards this unification goal. It requires dynamic routing between IP, digital, analog and GSM networks. A decision-making framework is presented that can handle ...