465 research outputs found
Seamless Infrastructure independent Multi Homed NEMO Handoff Using Effective and Timely IEEE 802.21 MIH triggers
Handoff performance of NEMO BS protocol with existent improvement proposals
is still not sufficient for real time and QoS-sensitive applications and
further optimizations are needed. When dealing with single homed NEMO, handoff
latency and packet loss become irreducible all optimizations included, so that
it is impossible to meet requirements of the above applications. Then, How to
combine the different Fast handoff approaches remains an open research issue
and needs more investigation. In this paper, we propose a new Infrastructure
independent handoff approach combining multihoming and intelligent
Make-Before-Break Handoff. Based on required Handoff time estimation, L2 and L3
handoffs are initiated using effective and timely MIH triggers, reducing so the
anticipation time and increasing the probability of prediction. We extend MIH
services to provide tunnel establishment and switching before link break. Thus,
the handoff is performed in background with no latency and no packet loss while
pingpong scenario is almost avoided. In addition, our proposal saves cost and
power consumption by optimizing the time of simultaneous use of multiple
interfaces. We provide also NS2 simulation experiments identifying suitable
parameter values used for estimation and validating the proposed mode
Mobility management in 5G heterogeneous networks
In recent years, mobile data traffic has increased exponentially as a result of widespread popularity and uptake of portable devices, such as smartphones, tablets and laptops. This growth has placed enormous stress on network service providers who are committed to offering the best quality of service to consumer groups. Consequently, telecommunication engineers are investigating innovative solutions to accommodate the additional load offered by growing numbers of mobile users.
The fifth generation (5G) of wireless communication standard is expected to provide numerous innovative solutions to meet the growing demand of consumer groups. Accordingly the ultimate goal is to achieve several key technological milestones including up to 1000 times higher wireless area capacity and a significant cut in power consumption.
Massive deployment of small cells is likely to be a key innovation in 5G, which enables frequent frequency reuse and higher data rates. Small cells, however, present a major challenge for nodes moving at vehicular speeds. This is because the smaller coverage areas of small cells result in frequent handover, which leads to lower throughput and longer delay.
In this thesis, a new mobility management technique is introduced that reduces the number of handovers in a 5G heterogeneous network. This research also investigates techniques to accommodate low latency applications in nodes moving at vehicular speeds
A network mobility management architecture for a heteregeneous network environment
Network mobility management enables mobility of personal area networks and vehicular networks across heterogeneous access networks using a Mobile Router. This dissertation presents a network mobility management architecture for minimizing the impact of handoffs on the communications of nodes in the mobile network. The architecture addresses mobility in legacy networks without infrastructure support, but can also exploit infrastructure support for improved handoff performance. Further, the proposed architecture increases the efficiency of communications of nodes in the mobile network with counter parts in the fixed network through the use of caching and route optimization. The performance and costs of the proposed architecture are evaluated through empirical and numerical analysis. The analysis shows the feasibility of the architecture in the networks of today and in those of the near future.Verkkojen liikkuuvudenhallinta mahdollistaa henkilökohtaisten ja ajoneuvoihin asennettujen verkkojen liikkuvuuden heterogeenisessä verkkoympäristössä käyttäen liikkuvaa reititintä. Tämä väitöskirja esittää uuden arkkitehtuurin verkkojen liikkuvuudenhallintaan, joka minimoi verkonvaihdon vaikutuksen päätelaitteiden yhteyksiin.
Vanhoissa verkoissa, joiden infrastruktuuri ei tue verkkojen liikkuvuutta, verkonvaihdos täytyy hallita liikkuvassa reitittimessa. Standardoitu verkkojen liikkuvuudenhallintaprotokolla NEMO mahdollistaa tämän käyttäen ankkurisolmua kiinteässä verkossa pakettien toimittamiseen päätelaitteiden kommunikaatiokumppaneilta liikkuvalle reitittimelle. NEMO:ssa verkonvaihdos aiheuttaa käynnissä olevien yhteyksien keskeytymisen yli sekunnin mittaiseksi ajaksi, aiheuttaen merkittävää häiriötä viestintäsovelluksille.
Esitetyssä arkkitehtuurissa verkonvaihdon vaikutus minimoidaan varustamalla liikkuva reititin kahdella radiolla. Käyttäen kahta radiota liikkuva reititin pystyy suorittamaan verkonvaihdon keskeyttämättä päätelaitteiden yhteyksiä, mikäli verkonvaihtoon on riittävästi aikaa. Käytettävissa oleva aika riippuu liikkuvan reitittimen nopeudesta ja radioverkon rakenteesta. Arkkitehtuuri osaa myös hyödyntää infrastruktuurin tukea saumattomaan verkonvaihtoon. Verkkoinfrastruktuurin tuki nopeuttaa verkonvaihdosprosessia, kasvattaenmaksimaalista verkonvaihdos tahtia. Tällöin liikkuva reitin voi käyttää lyhyen kantaman radioverkkoja, joiden solun säde on yli 80m, ajonopeuksilla 90m/s asti ilman, että verkonvaihdos keskeyttää päätelaitteiden yhteyksiä.
Lisäksi ehdotettu arkkitehtuuri tehostaa kommunikaatiota käyttäen cache-palvelimia liikkuvassa ja kiinteässä verkossa ja optimoitua reititystä liikkuvien päätelaitteiden ja kiinteässä verkossa olevien kommunikaatiosolmujen välillä. Cache-palvelinarkkitehtuuri hyödyntää vapaita radioresursseja liikkuvan verkon cache-palvelimen välimuistin päivittämiseen. Heterogeenisessä verkkoympäristossä cache-palvelimen päivitys suoritetaan lyhyen kantaman laajakaistaisia radioverkkoja käyttäen. Liikkuvan reitittimen siirtyessä laajakaistaisen radioverkon peitealueen ulkopuolelle päätelaitteille palvellaan sisältöä, kuten www sivuja tai videota cache-palvelimelta, säästäen laajemman kantaman radioverkon rajoitetumpia resursseja.
Arkkitehtuurissa käytetään optimoitua reititystä päätelaitteiden ja niiden kommunikaatiokumppaneiden välillä. Optimoitu reititysmekanismi vähentää liikkuvuudenhallintaan käytettyjen protokollien langattoman verkon resurssien kulutusta. Lisäksi optimoitu reititysmekanismi tehostaa pakettien reititystä käyttäen suorinta reittiä kommunikaatiosolmujen välillä.
Esitetyn arkkitehtuurin suorituskyky arvioidaan empiirisen ja numeerisen analyysin avulla. Analyysi arvioi arkkitehtuurin suorituskykyä ja vertaa sitä aikaisemmin ehdotettuihin ratkaisuihin ja osoittaa arkkitehtuurin soveltuvan nykyisiin ja lähitulevaisuuden langattomiin verkkoihin.reviewe
Context-aware multi-attribute decision multi - attribute decision making for radio access technology selection in ultra dense network
Ultra Dense Network (UDN) is the extreme densification of heterogeneous Radio Access
Technology (RAT) that is deployed closely in coordinated or uncoordinated manner. The densification of RAT forms an overlapping zone of signal coverage leading to the frequent service handovers among the RAT, thus degrading overall system performance. The current RAT selection approach is biased towards network-centric criteria pertaining to signal strength. However, the paradigm shift from network-centric to user-centric approach necessitates a multi-criteria selection process, with methodology
relating to both network and user preferences in the context of future generation networks. Hence, an effective selection approach is required to avoid unnecessary handovers in RAT. The main aim of this study is to propose the Context-aware Multiattribute decision making for RAT (CMRAT) selection for investigating the need to choose a new RAT and further determine the best amongst the available methods. The
CMRAT consists of two mechanisms, namely the Context-aware Analytical Hierarchy Process (CAHP) and Context-aware Technique for Order Preference by Similarity to an Ideal Solution (CTOPSIS). The CAHP mechanism measures the need to switch from the current RAT, while CTOPSIS aids in decision making to choose the best target RAT. A series of experimental studies were conducted to validate the effectiveness of CMRAT for achieving improved system performance. The investigation utilises shopping mall and urban dense network scenarios to evaluate the performance of RAT selection through simulation. The findings demonstrated that the CMRAT approach reduces delay and the number of handovers leading to an improvement of throughput and packet delivery ratio when compared to that of the commonly used A2A4-RSRQ approach. The CMRAT approach is effective in the RAT selection within UDN environment, thus supporting heterogeneous RAT deployment in future 5G networks. With context-aware selection, the user-centric feature is also emphasized
The Design of Efficient Internetwork Authentication for Ubiquitous Wireless Communications
A variety of wireless technologies have been
standardized and commercialized, but no single solution is
considered the best to satisfy all communication needs due
to different coverage and bandwidth limitations. Therefore,
internetworking between heterogeneous wireless networks
is extremely important for ubiquitous and high performance
wireless communications. The security problem is
one of the major challenges in internetworking. To date,
most research on internetwork authentication has focused
on centralized authentication approaches, where the home
network participates in each authentication process. For
high latency between the home and visiting networks, such
approaches tend to be inefficient. In this paper, we describe
chained authentication, which requires collaboration between
adjacent networks without involvement of the home
network. After categorizing chained protocols, we propose
a novel design of chained authentication methods under
3G-WLAN internetworking. The experiments show that
proactive context transfer and ticket forwarding reduce the
3G authentication latency to 36.8% and WLAN EAP-TLS
latency to 23.1% when RTT between visiting and home
networks is 200 ms
Support infrastructures for multimedia services with guaranteed continuity and QoS
Advances in wireless networking and content delivery systems are enabling new challenging provisioning scenarios where a growing number of users access multimedia services, e.g., audio/video streaming, while moving among different points of attachment to the Internet, possibly with different connectivity technologies, e.g., Wi-Fi, Bluetooth, and cellular 3G. That calls for novel middlewares capable of dynamically personalizing service provisioning to the characteristics of client environments, in particular to
discontinuities in wireless resource availability due to handoffs. This dissertation proposes a novel middleware solution, called MUM, that performs effective and context-aware handoff management to transparently avoid service interruptions during both horizontal and vertical handoffs. To achieve the goal, MUM exploits the full visibility of wireless connections available in client localities and their handoff implementations (handoff awareness), of service quality requirements and handoff-related quality degradations (QoS awareness), and of network topology and resources available in current/future localities (location awareness). The design and implementation of the all main MUM components along with extensive on the field trials of the realized middleware architecture confirmed the validity of the proposed full
context-aware handoff management approach. In particular, the reported experimental results demonstrate that MUM can effectively maintain service continuity for a wide range of different multimedia services by exploiting handoff prediction mechanisms, adaptive buffering and pre-fetching techniques, and proactive re-addressing/re-binding
Mobility and Handoff Management in Wireless Networks
With the increasing demands for new data and real-time services, wireless
networks should support calls with different traffic characteristics and
different Quality of Service (QoS)guarantees. In addition, various wireless
technologies and networks exist currently that can satisfy different needs and
requirements of mobile users. Since these different wireless networks act as
complementary to each other in terms of their capabilities and suitability for
different applications, integration of these networks will enable the mobile
users to be always connected to the best available access network depending on
their requirements. This integration of heterogeneous networks will, however,
lead to heterogeneities in access technologies and network protocols. To meet
the requirements of mobile users under this heterogeneous environment, a common
infrastructure to interconnect multiple access networks will be needed. In this
chapter, the design issues of a number of mobility management schemes have been
presented. Each of these schemes utilizes IP-based technologies to enable
efficient roaming in heterogeneous network. Efficient handoff mechanisms are
essential for ensuring seamless connectivity and uninterrupted service
delivery. A number of handoff schemes in a heterogeneous networking environment
are also presented in this chapter.Comment: 28 pages, 11 figure
Improved Vertical Handoff Schemes for K-Tier Heterogeneous Wireless Network
The vertical hando_ schemes for heterogeneous wireless networks are presented in the thesis. A heterogeneous network consists of multiple tiers of available wireless net-works, framed as K-tier heterogeneous wireless network (KHWN). A typical KHWN adopted in the thesis consists of Global System for Mobile communication (GSM), Universal Mobile Telecommunications System (UMTS), Wireless Local Area Network (WLAN) and Long Term Evolution (LTE). The hando_ scheme considers the Receiv- ing Signal Strength (RSS)and Signal to Interference and Noise Ratio (SINR) with the tra_c cost as the key parameters for vertical hando_ decision making process. The key parameter RSS is estimated through a proposed path loss model based on local terrain and is observed to be better as compared to the earlier empirical models. With the local terrain input, the path loss model and RSS has been estimated for GSM, UMTS, WLAN and LTE networks. Following this a VHO scheme is proposed for voice and data communication. Subsequently this SINR and a KHWN consisting of multi-tier with the four types of services viz. voice call, video streaming, web brows- ing and telemetry are considered. In this multi-hierarchy decision making process the best suited Analytical and Hierarchical Process (AHP) is applied, for the decision making process in VHO. The proposed scheme of vertical hando_ provides higher QoS than the earlier algorithms of Combined SINR based Vertical Hando_ (CSVH) and Multi-dimensional SINR based vertical hando_ (MSVH). Also the unnecessary VHO are controlled by the proposed scheme. The result shows that the proposed scheme provides low cost tra_c and overall system throughput with a control of unnecessary hando_s for all kinds of services within the KHWN
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