14 research outputs found
Robust header compression over IEEE 802 networks
Tese de mestrado. Redes e Serviços de Comunicação. Faculdade de Engenharia. Universidade do Porto, INESC Porto. 200
Robust Header Compression (ROHC) in Next-Generation Network Processors
Robust Header Compression (ROHC) provides for more efficient use of radio links for wireless communication in a packet switched network. Due to its potential advantages in the wireless access area andthe proliferation of network processors in access infrastructure, there exists a need to understand the resource requirements and architectural implications of implementing ROHC in this environment. We presentan analysis of the primary functional blocks of ROHC and extract the architectural implications on next-generation network processor design for wireless access. The discussion focuses on memory space andbandwidth dimensioning as well as processing resource budgets. We conclude with an examination of resource consumption and potential performance gains achievable by offloading computationally intensiveROHC functions to application specific hardware assists. We explore the design tradeoffs for hardware as-sists in the form of reconfigurable hardware, Application-Specific Instruction-set Processors (ASIPs), andApplication-Specific Integrated Circuits (ASICs)
Adaptive header compression techniques for mobile multimedia networks
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Convergence of packet communications over the evolved mobile networks; signal processing and protocol performance
In this thesis, the convergence of packet communications over the evolved mobile networks is studied. The Long Term Evolution (LTE) process is dominating the Third Generation Partnership Project (3GPP) in order to bring technologies to the markets in the spirit of continuous innovation. The global markets of mobile information services are growing towards the Mobile Information Society.
The thesis begins with the principles and theories of the multiple-access transmission schemes, transmitter receiver techniques and signal processing algorithms. Next, packet communications and Internet protocols are referred from the IETF standards with the characteristics of mobile communications in the focus. The mobile network architecture and protocols bind together the evolved packet system of Internet communications to the radio access network technologies. Specifics of the traffic models are shortly visited for their statistical meaning in the radio performance analysis. Radio resource management algorithms and protocols, also procedures, are covered addressing their relevance for the system performance. Throughout these Chapters, the commonalities and differentiators of the WCDMA, WCDMA/HSPA and LTE are covered. The main outcome of the thesis is the performance analysis of the LTE technology beginning from the early discoveries to the analysis of various system features and finally converging to an extensive system analysis campaign. The system performance is analysed with the characteristics of voice over the Internet and best effort traffic of the Internet. These traffic classes represent the majority of the mobile traffic in the converged packet networks, and yet they are simple enough for a fair and generic analysis of technologies. The thesis consists of publications and inventions created by the author that proposed several improvements to the 3G technologies towards the LTE. In the system analysis, the LTE showed by the factor of at least 2.5 to 3 times higher system measures compared to the WCDMA/HSPA reference. The WCDMA/HSPA networks are currently available with over 400 million subscribers and showing increasing growth, in the meanwhile the first LTE roll-outs are scheduled to begin in 2010. Sophisticated 3G LTE mobile devices are expected to appear fluently for all consumer segments in the following years
Quality aspects of Internet telephony
Internet telephony has had a tremendous impact on how people communicate.
Many now maintain contact using some form of Internet telephony.
Therefore the motivation for this work has been to address the quality aspects
of real-world Internet telephony for both fixed and wireless telecommunication.
The focus has been on the quality aspects of voice communication,
since poor quality leads often to user dissatisfaction. The scope of the work
has been broad in order to address the main factors within IP-based voice
communication.
The first four chapters of this dissertation constitute the background
material. The first chapter outlines where Internet telephony is deployed
today. It also motivates the topics and techniques used in this research.
The second chapter provides the background on Internet telephony including
signalling, speech coding and voice Internetworking. The third chapter
focuses solely on quality measures for packetised voice systems and finally
the fourth chapter is devoted to the history of voice research.
The appendix of this dissertation constitutes the research contributions.
It includes an examination of the access network, focusing on how calls are
multiplexed in wired and wireless systems. Subsequently in the wireless
case, we consider how to handover calls from 802.11 networks to the cellular
infrastructure. We then consider the Internet backbone where most of our
work is devoted to measurements specifically for Internet telephony. The
applications of these measurements have been estimating telephony arrival
processes, measuring call quality, and quantifying the trend in Internet telephony
quality over several years. We also consider the end systems, since
they are responsible for reconstructing a voice stream given loss and delay
constraints. Finally we estimate voice quality using the ITU proposal PESQ
and the packet loss process.
The main contribution of this work is a systematic examination of Internet
telephony. We describe several methods to enable adaptable solutions
for maintaining consistent voice quality. We have also found that relatively
small technical changes can lead to substantial user quality improvements.
A second contribution of this work is a suite of software tools designed to
ascertain voice quality in IP networks. Some of these tools are in use within
commercial systems today
Cross-layer analysis for video transmission over COFDM-based wireless local area networks
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
A Survey on Data Plane Programming with P4: Fundamentals, Advances, and Applied Research
With traditional networking, users can configure control plane protocols to
match the specific network configuration, but without the ability to
fundamentally change the underlying algorithms. With SDN, the users may provide
their own control plane, that can control network devices through their data
plane APIs. Programmable data planes allow users to define their own data plane
algorithms for network devices including appropriate data plane APIs which may
be leveraged by user-defined SDN control. Thus, programmable data planes and
SDN offer great flexibility for network customization, be it for specialized,
commercial appliances, e.g., in 5G or data center networks, or for rapid
prototyping in industrial and academic research. Programming
protocol-independent packet processors (P4) has emerged as the currently most
widespread abstraction, programming language, and concept for data plane
programming. It is developed and standardized by an open community and it is
supported by various software and hardware platforms. In this paper, we survey
the literature from 2015 to 2020 on data plane programming with P4. Our survey
covers 497 references of which 367 are scientific publications. We organize our
work into two parts. In the first part, we give an overview of data plane
programming models, the programming language, architectures, compilers,
targets, and data plane APIs. We also consider research efforts to advance P4
technology. In the second part, we analyze a large body of literature
considering P4-based applied research. We categorize 241 research papers into
different application domains, summarize their contributions, and extract
prototypes, target platforms, and source code availability.Comment: Submitted to IEEE Communications Surveys and Tutorials (COMS) on
2021-01-2
MOBILITY SUPPORT ARCHITECTURES FOR NEXT-GENERATION WIRELESS NETWORKS
With the convergence of the wireless networks and the Internet and the booming
demand for multimedia applications, the next-generation (beyond the third generation, or
B3G) wireless systems are expected to be all IP-based and provide real-time and non-real-time
mobile services anywhere and anytime. Powerful and efficient mobility support is
thus the key enabler to fulfil such an attractive vision by supporting various mobility
scenarios. This thesis contributes to this interesting while challenging topic.
After a literature review on mobility support architectures and protocols, the thesis
starts presenting our contributions with a generic multi-layer mobility support framework,
which provides a general approach to meet the challenges of handling comprehensive
mobility issues. The cross-layer design methodology is introduced to coordinate the
protocol layers for optimised system design. Particularly, a flexible and efficient cross-layer
signalling scheme is proposed for interlayer interactions. The proposed generic
framework is then narrowed down with several fundamental building blocks identified to
be focused on as follows.
As widely adopted, we assume that the IP-based access networks are organised into
administrative domains, which are inter-connected through a global IP-based wired core
network. For a mobile user who roams from one domain to another, macro (inter-domain)
mobility management should be in place for global location tracking and effective handoff
support for both real-time and non-real-lime applications. Mobile IP (MIP) and the Session
Initiation Protocol (SIP) are being adopted as the two dominant standard-based macro-mobility
architectures, each of which has mobility entities and messages in its own right.
The work explores the joint optimisations and interactions of MIP and SIP when utilising
the complementary power of both protocols. Two distinctive integrated MIP-SIP
architectures are designed and evaluated, compared with their hybrid alternatives and other
approaches. The overall analytical and simulation results shown significant performance
improvements in terms of cost-efficiency, among other metrics.
Subsequently, for the micro (intra-domain) mobility scenario where a mobile user
moves across IP subnets within a domain, a micro mobility management architecture is
needed to support fast handoffs and constrain signalling messaging loads incurred by intra-domain
movements within the domain. The Hierarchical MIPv6 (HMIPv6) and the Fast
Handovers for MIPv6 (FMIPv6) protocols are selected to fulfil the design requirements.
The work proposes enhancements to these protocols and combines them in an optimised
way. resulting in notably improved performances in contrast to a number of alternative
approaches