This document discusses solutions for implementing interactivity in mobile multimedia systems. It outlines the importance of interactivity for mobile applications and services. Some key challenges are large round-trip delays due to retransmissions. Solutions proposed include hybrid-ARQ at the Node B to reduce delays, shorter transmission time intervals, Node B controlled scheduling to adapt faster to channel conditions, and adaptive modulation and coding. These solutions aim to improve system capacity, throughput, and reduce delays to better support interactive applications on mobile devices.
The document discusses signaling fundamentals in a base station subsystem (BSS). It describes the A, Abis, and Um interfaces between the BSS components. The A interface uses SS7 protocol layers including the physical layer, MTP, SCCP and BSSAP. The BSSAP layer supports BSSMAP messages for connectionless and connection-oriented signaling between the BSS and MSC.
GSM-architecture-Location tracking and call setup- Mobility management- Handover-
Security-GSM SMS –International roaming for GSM- call recording functions-subscriber and
service data mgt –-Mobile Number portability -VoIP service for Mobile Networks – GPRS –
Architecture-GPRS procedures-attach and detach procedures-PDP context procedure-
combined RA/LA update procedures-Billing
This document discusses transcoding and transcoder-free operations in GSM and UMTS networks. Transcoding refers to converting between different encoding schemes and introduces distortions and delays. Tandem-free operation (TFO) and transcoder-free operation (TrFO) aim to transmit voice without transcoding. TFO operates in GSM networks by transmitting compressed voice over 64 kbps links, while TrFO operates in packet-based UMTS networks without transcoders. TrFO overcomes some TFO limitations and improves voice quality and network capacity. The interworking of TFO and TrFO in mixed GSM/UMTS networks requires further consideration.
Mobility Management Scheme for Mobile Communication Systems. A Reviewiosrjce
An intelligent mobility management scheme for mobile communication systems was studied. From
the result obtained, it was discovered that mobile to mobile call setup times showed a better performance as
compared to fixed network to mobile call setup and mobile to fixed call setup times. Moreover, increasing the
number of location areas within the switch does not affect inter-MSC handover and location updates since the
size of the switch coverage area remains the same. And when the location areas within the switch is increased,
intra-MSC location updates and handover also increases. Finally, user mobility directly affects the signaling
traffic for handover, location management, radio resource allocation and routing.
GPRS (General Packet Radio Service) improves on existing cellular data services by using a packet switched network rather than a circuit switched one. This allows for more efficient use of network resources and bandwidth. GPRS allows multiple users to share the same physical channel and users are billed based on the amount of data transferred rather than connection time. Maximum transfer rates are improved to 171.2 kbps.
The document discusses Short Message Service (SMS) and its strengths and architecture. It describes how SMS uses signaling channels to transmit short messages of up to 160 characters globally. SMS is stateless, asynchronous, and always connected. The document outlines the SMS architecture including Short Message Mobile Terminated (SMMT) and Short Message Mobile Originated (SMMO) processes. It also discusses how SMS can be used as an information bearer and for value-added services and location-based services.
Global system for mobile communication Introduction, GSM architecture, GSM interfaces, Signal processing in GSM,
Frame structure of GSM, Channels used in GSM
Capacity utilization and admission control in the downlinkof WMAX marwaeng
This document discusses admission control in the downlink of mobile WiMAX networks. It identifies eight different traffic types that could be randomly deployed in the coverage area of a base station or relay station. These include real-time and non-real-time, constant bit rate and variable bit rate applications like gaming, web browsing, video conferencing, streaming media, VoIP, and instant messaging. The document proposes dividing the total bandwidth capacity between constant bit rate and variable bit rate traffics. It simulates admitting different traffics based on their signal to noise ratio, bit rate, and available bandwidth. The results showed the proposed admission policy utilizes capacity more efficiently than conventional policies.
The document discusses signaling fundamentals in a base station subsystem (BSS). It describes the A, Abis, and Um interfaces between the BSS components. The A interface uses SS7 protocol layers including the physical layer, MTP, SCCP and BSSAP. The BSSAP layer supports BSSMAP messages for connectionless and connection-oriented signaling between the BSS and MSC.
GSM-architecture-Location tracking and call setup- Mobility management- Handover-
Security-GSM SMS –International roaming for GSM- call recording functions-subscriber and
service data mgt –-Mobile Number portability -VoIP service for Mobile Networks – GPRS –
Architecture-GPRS procedures-attach and detach procedures-PDP context procedure-
combined RA/LA update procedures-Billing
This document discusses transcoding and transcoder-free operations in GSM and UMTS networks. Transcoding refers to converting between different encoding schemes and introduces distortions and delays. Tandem-free operation (TFO) and transcoder-free operation (TrFO) aim to transmit voice without transcoding. TFO operates in GSM networks by transmitting compressed voice over 64 kbps links, while TrFO operates in packet-based UMTS networks without transcoders. TrFO overcomes some TFO limitations and improves voice quality and network capacity. The interworking of TFO and TrFO in mixed GSM/UMTS networks requires further consideration.
Mobility Management Scheme for Mobile Communication Systems. A Reviewiosrjce
An intelligent mobility management scheme for mobile communication systems was studied. From
the result obtained, it was discovered that mobile to mobile call setup times showed a better performance as
compared to fixed network to mobile call setup and mobile to fixed call setup times. Moreover, increasing the
number of location areas within the switch does not affect inter-MSC handover and location updates since the
size of the switch coverage area remains the same. And when the location areas within the switch is increased,
intra-MSC location updates and handover also increases. Finally, user mobility directly affects the signaling
traffic for handover, location management, radio resource allocation and routing.
GPRS (General Packet Radio Service) improves on existing cellular data services by using a packet switched network rather than a circuit switched one. This allows for more efficient use of network resources and bandwidth. GPRS allows multiple users to share the same physical channel and users are billed based on the amount of data transferred rather than connection time. Maximum transfer rates are improved to 171.2 kbps.
The document discusses Short Message Service (SMS) and its strengths and architecture. It describes how SMS uses signaling channels to transmit short messages of up to 160 characters globally. SMS is stateless, asynchronous, and always connected. The document outlines the SMS architecture including Short Message Mobile Terminated (SMMT) and Short Message Mobile Originated (SMMO) processes. It also discusses how SMS can be used as an information bearer and for value-added services and location-based services.
Global system for mobile communication Introduction, GSM architecture, GSM interfaces, Signal processing in GSM,
Frame structure of GSM, Channels used in GSM
Capacity utilization and admission control in the downlinkof WMAX marwaeng
This document discusses admission control in the downlink of mobile WiMAX networks. It identifies eight different traffic types that could be randomly deployed in the coverage area of a base station or relay station. These include real-time and non-real-time, constant bit rate and variable bit rate applications like gaming, web browsing, video conferencing, streaming media, VoIP, and instant messaging. The document proposes dividing the total bandwidth capacity between constant bit rate and variable bit rate traffics. It simulates admitting different traffics based on their signal to noise ratio, bit rate, and available bandwidth. The results showed the proposed admission policy utilizes capacity more efficiently than conventional policies.
GPRS is a packet-based mobile data service on GSM networks. It provides higher speed data transmission than previous GSM data services. The GPRS architecture introduces two new network nodes - SGSN and GGSN. SGSN handles mobility management and packet transmission between MS and GGSN, while GGSN connects the GPRS network to external packet networks like the Internet. GPRS enhances the GSM network by allowing dynamic allocation of bandwidth and intermittent data transmission, making it suitable for bursty, low-volume data applications.
Introduction of GPRS
QoS in GPRS
GPRS Network Architecture
GPRS Network Operation
Data Service,
Application,
Limitation In GPRS
Billing and Charging In GPRS
Umts femto access point for higher data rate and better quality of service to...eSAT Publishing House
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.
The document describes the GSM signaling protocol architecture, which includes protocols for radio resource management, mobility management, connection management, and the mobile application part (MAP). It focuses on the radio resource management layer, which handles radio channel configuration and handovers between cells and base stations. It also describes the control channels used for signaling between mobiles and base stations, and the mobility management layer, which handles location updates as subscribers move between different areas. Finally, it provides details on the BSS application part (BSSAP), which includes the direct transfer application part (DTAP) and BSS management application part (BSSMAP) to transfer messages between network components.
The document describes the protocol architecture of GSM, which is a digital cellular communications system that provides digital transmission, ISDN compatibility, and worldwide roaming. It discusses the nomenclature, protocol stack, and interfaces in GSM. The protocol stack consists of physical, data link, and networking layers. The physical layer handles radio transmission, while the data link layer provides error-free transmission using LAPD and LAPDm protocols. The networking layer implements mobility management, call control, and short message service using various signaling messages and protocols.
A digital switch is a device that handles digital signals generated at or passed through a telephone company central office and forwards them across the company's backbone network. ... A centrex is a digital switch at the central office that manages to switch for the private company from the central office.
This document provides an overview of the 3GPP Long Term Evolution (LTE) physical layer. Key points include:
- LTE uses OFDM on the downlink and SC-FDMA on the uplink to provide peak data rates of 100 Mbps downlink and 50 Mbps uplink.
- OFDM divides the available bandwidth into multiple narrow subcarriers to combat multipath interference and eliminate inter-symbol interference.
- The document discusses technologies like OFDMA, MIMO, and the LTE frame structure in depth.
- The physical layer supports scalable bandwidths from 1.25 MHz to 20 MHz and multiple antenna configurations on uplink and downlink.
-
This document discusses cellular network planning and optimization, specifically for WCDMA radio resource management (RRM). It covers several key topics:
Quality of Service (QoS) in UMTS is achieved through a system of bearers that negotiate bandwidth and latency requirements between network elements. Radio access bearers connect the user equipment to the core network.
RRM functions like admission control, power control, handover control, and packet scheduling work to guarantee QoS, maintain coverage, and optimize cell capacity in WCDMA networks. Power control is a critical RRM mechanism that uses fast and outer loop techniques to control transmission power and mitigate interference.
- GPRS is an upgrade to GSM that allows packet-based data services and efficient use of network bandwidth. It provides higher data rates than GSM and constant connectivity.
- The GPRS network architecture introduces new network elements like the SGSN and GGSN to route data packets. The SGSN manages packet data in its service area while the GGSN connects the GPRS network to external packet networks.
- Session management in GPRS includes establishing PDP contexts for data transfer sessions and location management tracks the routing area of mobile devices through routing area updates.
This document provides an introduction to traffic engineering concepts for telecommunication networks. It discusses key topics like traffic statistics, patterns, units of measurement, grade of service, blocking probability, congestion, modeling traffic, network organization, and management. The purpose of traffic engineering is to determine how to provide adequate service to subscribers while making economical use of network resources. It analyzes statistical properties of networks to design efficient models.
GPRS uses several interfaces to connect its core network elements and allow communication with external networks. The key interfaces include Um between the mobile station and GPRS network, Gb between the SGSN and BSS, Gn between SGSNs in the same network, Gp between SGSNs in different networks, and Gi between the GGSN and external data networks like the Internet. GPRS interfaces allow packet-switched connectivity and use protocols like GTP for tunneling within the core network.
General packet radio services (GPRS) is step to efficiently transport high-speed data over the current GSM and TDMA-based wireless network infrastructures.
Deployment of GPRS networks allows a variety of new applications ranging from mobile e-commerce to mobile corporate VPN access
Deployments of GPRS network has already taken place in several countries in Europe and the far east.
This document provides an overview of Wideband Code Division Multiple Access (WCDMA) technology. It discusses how WCDMA evolved from existing GSM and CDMA technologies to provide higher data rates and capacity. Key aspects of WCDMA include efficient power control, soft handover between cells, and the ability to allocate capacity between voice and data services. The document describes the basic architecture of a WCDMA network including the radio access network components like Node B base stations and radio network controllers.
This presentation covers:
How evolution has happened from First Generation Mobile Communication Systems to present day 3G/UMTS/WCMDA systems
Brief introduction of each Generation: GSM - 2G, 2.5 G - GPRS, 2.75G - EDGE, 3G and then LTE/4G
WCDMA (Wideband Code Division Multiple Access) is a 3G mobile technology that uses CDMA to allow multiple users to access a wide 5MHz radio channel simultaneously. Key features of WCDMA include fast power control to manage interference between users, and soft/softer handover which allows a mobile to connect to multiple base stations for better call quality as the user moves between cells. WCDMA was developed to provide higher data speeds and capacity over wireless networks compared to 2G technologies like GSM.
1) Transcoder Free Operation (TrFO) and Tandem Free Operation (TFO) allow for improved voice quality and reduced delay in UMTS and GSM networks respectively by removing transcoding steps from voice calls.
2) With TrFO, mobile-to-mobile calls in a UMTS network can use wideband codecs without transcoding, improving quality. TFO removes tandem transcoders from GSM calls by tunneling compressed audio between transcoding units.
3) Events like handovers can temporarily interrupt TrFO/TFO and require renegotiation or fallback to standard transcoding to maintain call quality.
The document provides an introduction to 2G/3G and 4G core mobile networks. It discusses key network elements like BTS, BSC, RNC, SGSN, GGSN, eNodeB, MME, S-GW and P-GW. It provides an overview of the differences between circuit switching and packet switching. It also summarizes simplified call flows for 2G/3G packet data and 4G, highlighting the core network elements involved and interfaces between them.
The document provides an agenda on GSM and GPRS theory that includes:
- An overview of GSM definition, history, services, system architecture, functional model, and interfaces
- Descriptions of the radio interface, A-bis, A-interface, signaling protocols, and inter-MSC signaling
- A brief history of GPRS and definitions of its new network elements and air and A-bis interfaces
This document discusses the challenges facing a company that produces traditional Japanese crafts called "Aburatorigami". The company wants to position their brand as luxurious but faces misconceptions about geisha culture. They also lack funds and the extensive selling efforts needed for long-term procurement. The document provides solutions and recommendations to address these issues.
GPRS is a packet-based mobile data service on GSM networks. It provides higher speed data transmission than previous GSM data services. The GPRS architecture introduces two new network nodes - SGSN and GGSN. SGSN handles mobility management and packet transmission between MS and GGSN, while GGSN connects the GPRS network to external packet networks like the Internet. GPRS enhances the GSM network by allowing dynamic allocation of bandwidth and intermittent data transmission, making it suitable for bursty, low-volume data applications.
Introduction of GPRS
QoS in GPRS
GPRS Network Architecture
GPRS Network Operation
Data Service,
Application,
Limitation In GPRS
Billing and Charging In GPRS
Umts femto access point for higher data rate and better quality of service to...eSAT Publishing House
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.
The document describes the GSM signaling protocol architecture, which includes protocols for radio resource management, mobility management, connection management, and the mobile application part (MAP). It focuses on the radio resource management layer, which handles radio channel configuration and handovers between cells and base stations. It also describes the control channels used for signaling between mobiles and base stations, and the mobility management layer, which handles location updates as subscribers move between different areas. Finally, it provides details on the BSS application part (BSSAP), which includes the direct transfer application part (DTAP) and BSS management application part (BSSMAP) to transfer messages between network components.
The document describes the protocol architecture of GSM, which is a digital cellular communications system that provides digital transmission, ISDN compatibility, and worldwide roaming. It discusses the nomenclature, protocol stack, and interfaces in GSM. The protocol stack consists of physical, data link, and networking layers. The physical layer handles radio transmission, while the data link layer provides error-free transmission using LAPD and LAPDm protocols. The networking layer implements mobility management, call control, and short message service using various signaling messages and protocols.
A digital switch is a device that handles digital signals generated at or passed through a telephone company central office and forwards them across the company's backbone network. ... A centrex is a digital switch at the central office that manages to switch for the private company from the central office.
This document provides an overview of the 3GPP Long Term Evolution (LTE) physical layer. Key points include:
- LTE uses OFDM on the downlink and SC-FDMA on the uplink to provide peak data rates of 100 Mbps downlink and 50 Mbps uplink.
- OFDM divides the available bandwidth into multiple narrow subcarriers to combat multipath interference and eliminate inter-symbol interference.
- The document discusses technologies like OFDMA, MIMO, and the LTE frame structure in depth.
- The physical layer supports scalable bandwidths from 1.25 MHz to 20 MHz and multiple antenna configurations on uplink and downlink.
-
This document discusses cellular network planning and optimization, specifically for WCDMA radio resource management (RRM). It covers several key topics:
Quality of Service (QoS) in UMTS is achieved through a system of bearers that negotiate bandwidth and latency requirements between network elements. Radio access bearers connect the user equipment to the core network.
RRM functions like admission control, power control, handover control, and packet scheduling work to guarantee QoS, maintain coverage, and optimize cell capacity in WCDMA networks. Power control is a critical RRM mechanism that uses fast and outer loop techniques to control transmission power and mitigate interference.
- GPRS is an upgrade to GSM that allows packet-based data services and efficient use of network bandwidth. It provides higher data rates than GSM and constant connectivity.
- The GPRS network architecture introduces new network elements like the SGSN and GGSN to route data packets. The SGSN manages packet data in its service area while the GGSN connects the GPRS network to external packet networks.
- Session management in GPRS includes establishing PDP contexts for data transfer sessions and location management tracks the routing area of mobile devices through routing area updates.
This document provides an introduction to traffic engineering concepts for telecommunication networks. It discusses key topics like traffic statistics, patterns, units of measurement, grade of service, blocking probability, congestion, modeling traffic, network organization, and management. The purpose of traffic engineering is to determine how to provide adequate service to subscribers while making economical use of network resources. It analyzes statistical properties of networks to design efficient models.
GPRS uses several interfaces to connect its core network elements and allow communication with external networks. The key interfaces include Um between the mobile station and GPRS network, Gb between the SGSN and BSS, Gn between SGSNs in the same network, Gp between SGSNs in different networks, and Gi between the GGSN and external data networks like the Internet. GPRS interfaces allow packet-switched connectivity and use protocols like GTP for tunneling within the core network.
General packet radio services (GPRS) is step to efficiently transport high-speed data over the current GSM and TDMA-based wireless network infrastructures.
Deployment of GPRS networks allows a variety of new applications ranging from mobile e-commerce to mobile corporate VPN access
Deployments of GPRS network has already taken place in several countries in Europe and the far east.
This document provides an overview of Wideband Code Division Multiple Access (WCDMA) technology. It discusses how WCDMA evolved from existing GSM and CDMA technologies to provide higher data rates and capacity. Key aspects of WCDMA include efficient power control, soft handover between cells, and the ability to allocate capacity between voice and data services. The document describes the basic architecture of a WCDMA network including the radio access network components like Node B base stations and radio network controllers.
This presentation covers:
How evolution has happened from First Generation Mobile Communication Systems to present day 3G/UMTS/WCMDA systems
Brief introduction of each Generation: GSM - 2G, 2.5 G - GPRS, 2.75G - EDGE, 3G and then LTE/4G
WCDMA (Wideband Code Division Multiple Access) is a 3G mobile technology that uses CDMA to allow multiple users to access a wide 5MHz radio channel simultaneously. Key features of WCDMA include fast power control to manage interference between users, and soft/softer handover which allows a mobile to connect to multiple base stations for better call quality as the user moves between cells. WCDMA was developed to provide higher data speeds and capacity over wireless networks compared to 2G technologies like GSM.
1) Transcoder Free Operation (TrFO) and Tandem Free Operation (TFO) allow for improved voice quality and reduced delay in UMTS and GSM networks respectively by removing transcoding steps from voice calls.
2) With TrFO, mobile-to-mobile calls in a UMTS network can use wideband codecs without transcoding, improving quality. TFO removes tandem transcoders from GSM calls by tunneling compressed audio between transcoding units.
3) Events like handovers can temporarily interrupt TrFO/TFO and require renegotiation or fallback to standard transcoding to maintain call quality.
The document provides an introduction to 2G/3G and 4G core mobile networks. It discusses key network elements like BTS, BSC, RNC, SGSN, GGSN, eNodeB, MME, S-GW and P-GW. It provides an overview of the differences between circuit switching and packet switching. It also summarizes simplified call flows for 2G/3G packet data and 4G, highlighting the core network elements involved and interfaces between them.
The document provides an agenda on GSM and GPRS theory that includes:
- An overview of GSM definition, history, services, system architecture, functional model, and interfaces
- Descriptions of the radio interface, A-bis, A-interface, signaling protocols, and inter-MSC signaling
- A brief history of GPRS and definitions of its new network elements and air and A-bis interfaces
This document discusses the challenges facing a company that produces traditional Japanese crafts called "Aburatorigami". The company wants to position their brand as luxurious but faces misconceptions about geisha culture. They also lack funds and the extensive selling efforts needed for long-term procurement. The document provides solutions and recommendations to address these issues.
Vendor Product Attribute Addon - Magento Multi-Vendor Marketplace by CedCommerceCedCommerce
Vendor Product Attribute Addon allows the vendors to create their own attributes and assign them to the Attribute Set being provided to them. The vendors now have the power to manage the functionalities of their Attribute Set without the intervention of the admin.
Formfunc Installations manufactures custom furniture in contemporary, classical, and country styles that can be detailed to meet clients' specific requirements. They have a blend of private and corporate clients and work closely with architects and designers. Formfunc has established a reputation for creative solutions, uncompromising quality and material selection, and precision installation work. They design, manufacture, and coordinate all projects to meet clients' needs.
Effective presentation skills A Lecture By Mr Allah Dad KhanMr.Allah Dad Khan
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against developing mental illness and improve symptoms for those who already have a condition.
Un objeto de aprendizaje es un conjunto de recursos digitales con un propósito educativo que incluye contenido, actividades de aprendizaje y elementos de contextualización. Los objetos de aprendizaje son autocontenidos, reutilizables y etiquetados con metadatos para facilitar su almacenamiento e identificación. Las características clave de los objetos de aprendizaje son que son unidades independientes y flexibles que pueden ensamblarse para formar secuencias de aprendizaje.
JavaScript goes Enterprise - Node.js-Anwendungen mit Visual Studio und den No...Peter Hecker
Node.js hat sich schnell zu einer der beliebtesten Plattformen für das Schreiben von serverseitigem Code entwickelt. Das Node.js-Framework basiert auf der Google V8 JavaScript-Engine und ermöglicht Entwicklern serverseitige Anwendungen in JavaScript zu implementieren. Im November 2013 hat Microsoft die "Node.js Tools für Visual Studio (NTVS)" in einer ersten Alpha vorgestellt. Damit können Windows-Entwickler Node.js Anwendungen direkt in Visual Studio entwickeln. Die NTVS werden als Plug-in in Visual Studio integriert und bieten Zugriff auf die Codevervollständigung sowie die Debugging-, Profiling- und Deployment-Funktionen von Visual Studio. Zusätzlich enthält das Plug-in eine grafische Benutzeroberfläche für den Node Package Manager (npm). Damit lassen sich aus Visual Studio heraus Bibliotheken für das serverseitige JavaScript-Framework aus dem npm-Repository installieren. Auch die Anbindung an die Windows Azure - Plattform ist möglich. In diesem Vortrag werden die Node.js-Plattform sowie die Möglichkeiten der Node.js - Tools (NTJS) vorgestellt. Beispiele zeigen erste Anwendungsmöglichkeiten.
Aloe Vera juice contains leaf pulp that is rich in natural nutrients and fiber. Aloe Vera juice removes toxins, enhances your immune system and maintains a healthy digestion. It enable us to stay well and shed body mass.
Cross-Apps-Entwicklung für iPhone, Android und Co.Peter Hecker
Mit der Veröffentlichung von iPhone, iPod Touch sowie iPad und dem iPhone OS hat Apple den Markt für mobile Endgeräte massenfähig gemacht. Google liefert mit dem Android-Betriebssystem ebenfalls eine stetig wachsende Plattform. Einer der Erfolgsfaktoren ist der auf beiden Systemen verfügbaren Browser "Mobile Safari" bzw. die technologische Basis WebKit. Diese freie HTML-Rendering-Bibliothek wird nicht nur von Apple und Google eingesetzt, sondern auch von anderen Unternehmen, wie Nokia, Adobe und Blackberry verwendet: Einführung und Motivation, Die WebKit-Plattform, Überblick "mobile" Frameworks, Zusammenfassung und Fazit
The document discusses the proper use of the prepositions "for", "during", and "while" when referring to time. It explains that "for" is used to indicate a period of time, such as "for an hour". "During" is used before a noun to refer to an event or activity happening simultaneously, like "during the movie". "While" is also used to refer to simultaneous events or activities, but is followed by a clause with a subject and verb, such as "while I was watching TV". The document provides examples of correct and incorrect usage for each preposition.
La ley busca regular los arrendamientos de viviendas para garantizar el derecho a una vivienda digna. Siguiendo los principios de justicia social, igualdad y equidad, la ley promueve el arrendamiento socialmente responsable como vivienda complementaria y transitoria. Se crea una Superintendencia Nacional de Arrendamiento de Vivienda que velará por los derechos de arrendatarios y arrendadores y fijará los cánones de arriendo.
Coffee is prepared from roasted coffee beans, which are seeds from the Coffea plant. Coffee plants are cultivated in over 70 countries in equatorial regions. The two most commonly grown varieties are arabica and robusta. Coffee is one of the most popular drinks in the world and can be prepared in many ways. Moderate coffee consumption is benign or mildly beneficial for health, but excess may increase heart disease risk.
This document provides a slideshow summary of various memorable events that Cathy McDermott has been involved in over her career. Some of the events mentioned include golf events with professional golfer Gary Player in the late 1990s, fan appreciation events at The Master's golf tournament in Augusta, promoting a TV series at piers in San Francisco and New York which attracted thousands of attendees, organizing major author events at Kepler's Books featuring public figures like Colin Powell and Jimmy Carter, and coordinating events at institutions like Menlo College, San Francisco State University including athletics events, reunions and more. The slideshow highlights photos from these events over the years.
The market ended lower on February 3, with the Sensex closing down 285 points at 24,539 and the Nifty down 100 points at 7,455. Tata Steel, NTPC, BHEL, Hindalco and Cipla were major losers. Bharti Airtel, Bajaj Auto, Lupin and Wipro were gainers. The document recommends buying Tata Steel at Rs. 227, targeting Rs. 229/231/233 with a stop loss of Rs. 223. FIIs were net buyers of Rs. 253.88 crore on February 1.
This short document discusses Walt Disney. It does not provide many details about Walt Disney or his accomplishments. The document simply states his name and ends abruptly, offering no context or information.
Site supervisor-agent-manager-pts-cpcs-cscs-smsts-ioshPavel Babincak
This document is a CV for Pavel Babincak, who is seeking a position as a site supervisor or site manager in the Greater London area. He has over 10 years of experience managing construction projects in areas like new builds, refurbishments, fit-outs, and more. His skills include health and safety compliance, subcontractor management, scheduling, budgeting, and ensuring quality work. He is proficient in areas like building regulations, construction drawings, and computer programs.
This document analyzes the impact of signaling load on call blocking and dropping in UMTS networks. It calculates the acquisition time for different signaling service types based on message length and transmission rates. It then estimates the maximum number of signaling sessions that can be supported simultaneously within the control interval based on a signal-to-interference ratio analysis. An example traffic scenario is provided to illustrate the benefits of studying how different signaling loads affect network performance. The analysis aims to efficiently allocate radio resources and preserve quality of service for both signaling and user data traffic.
This document summarizes a research paper that proposes a new algorithm for calculating TCP timeout over wireless ad hoc networks. The current TCP timeout calculation does not adapt well to the unstable nature of wireless networks where factors like node mobility can cause estimated round trip times to vary greatly. The proposed algorithm aims to make timeout calculation more adaptive to network conditions in wireless ad hoc networks to improve TCP performance and quality of service for real-time multimedia applications. It describes challenges with existing TCP timeout approaches over wireless networks and reviews related literature before introducing the novel algorithm developed and tested through simulation.
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
Performance evaluation of bandwidth optimization algorithm (boa) in atm networkEditor Jacotech
domains: none of them are suitable, alone, for the wide range of traffic services expected in ATM-based networks. Therefore, some integration of these basic schemes should be considered. In this paper, we propose a new traffic control algorithm, called the Bandwidth optimization Algorithm (BOA). BOA is a multi-level control algorithm that attempts to optimally manage network resources and perform traffic control among a wide range of traffic services in ATM-based networks. The basic objective of BOA is to meet the quality of service requirements for different traffic sources, while making the best possible use of network bandwidth. In addition. BOA attempts to minimize network congestion in a preventive way.
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 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.
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.
Video steaming Throughput Performance Analysis over LTEiosrjce
This document analyzes the video streaming throughput performance over LTE networks using the OPNET simulation tool. It simulates two scenarios: 1) downlink and uplink video conferencing with static users and 2) the same with users moving at 30m/s. The key metrics measured are packet delay variation and end-to-end delay. The results show that static users experience higher packet delay variation than mobile users, likely due to increased traffic accumulation. End-to-end delay is also higher for static users compared to those moving at 30m/s.
This document analyzes the video streaming throughput performance over LTE networks using the OPNET simulation tool. It simulates two scenarios: 1) downlink and uplink video conferencing with static users and 2) the same with users moving at 30m/s. The key metrics measured are packet delay variation and end-to-end delay. The results show that static users experience higher packet delay variation than mobile users, likely due to increased traffic accumulation. End-to-end delay is also higher for static users compared to those moving at 30m/s.
The improvement of end to end delays in network management system using netwo...IJCNCJournal
The document summarizes research on improving end-to-end delays in a network management system using network coding. Specifically, it applies network coding to manage radio and television broadcast stations in a wireless network. The study shows that a proposed "Fast Forwarding Strategy" using network coding outperforms a classical routing strategy in reducing end-to-end delays from source to destination. It analyzes end-to-end delays theoretically using network calculus and conducts a practical study on a network of broadcast stations, finding the proposed strategy reduces delays compared to the classical strategy.
In the last few years, video streaming facilities over TCP or UDP, such as YouTube, Facetime, Daily-motion, Mobile video calling have become more and more popular. The important
challenge in streaming broadcasting over the Internet is to spread the uppermost potential quality,
observe to the broadcasting play out time limitation, and efficiently and equally share the offered
bandwidth with TCP or UDP, and additional traffic types. This work familiarizes the Streaming
Media Data Congestion Control protocol (SMDCC), a new adaptive broadcasting streaming
congestion management protocol in which the connection’s data packets transmission frequency is
adjusted allowing to the dynamic bandwidth share of connection using SMDCC, the bandwidth share
of a connection is projected using algorithms similar to those introduced in TCP Westwood. SMDCC
avoids the Slow Jump phase in TCP. As a result, SMDCC does not show the pronounced rate
alternations distinguishing of modern TCP, so providing congestion control that is more appropriate
for streaming broadcasting applications. Besides, SMDCC is fair, sharing the bandwidth equitably
among a set of SMDCC connections. Main benefit is robustness when packet harms are due to
indiscriminate errors, which is typical of wireless links and is becoming an increasing concern due to
the emergence of wireless Internet access. In the presence of indiscriminate errors, SMDCC is also
approachable to TCP Tahoe and Reno (TTR). We provide simulation results using the ns3 simulator
for our protocol running together with TCP Tahoe and Reno.
ADAPTIVE HANDOVER HYSTERESIS AND CALL ADMISSION CONTROL FOR MOBILE RELAY NODESIJCNCJournal
The aim of equipping a wireless network with a mobile relay node is to support broadband wireless communications for vehicular users and their devices. The high mobility of vehicular users, possibly at a very high velocity in the area in which two cells overlap, could cause the network to suffer from a reduced handover success rate and, hence, increased radio link failure. The combined impact of these problems is service interruptions to vehicular users. Thus, the handover schemes are crucial in solving these problems. In this work, we first present the adaptive handover hysteresis scheme for the wireless network with mobile relay nodes in the high-speed train scenario. Specifically, our proposed adaptive hysteresis scheme is based on the velocity of the train. Second, the handover call dropping probability is reduced by introducing a modified call admission control scheme to support radio resource reservation for handover calls that prioritizes handover calls of mobile relay over the other calls. The proposed solution in which adaptive parameter is combined with call admission control is evaluated by system level simulation. Our simulation results illustrate an increased handover success rate and reduced radio link failures.
S URVEY OF L TE D OWNLINK S CHEDULERS A LGORITHMS IN O PEN A CCESS S IM...ijwmn
he LTE/LTE-A has become a catchphrase for research
and lot of research are being conducted and
carried out in LTE in various issues by various peo
ple. New tools are developed and introduced in the
market to interpret the results of the new algorith
ms proposed by various people. Some tools are open
access which are free to use but some tools are pro
duced by the companies which are not open access. I
n
this paper some of the open access simulation tools
like LTE-Sim and NS-3 are analyzed and LTE downlin
k
scheduler algorithms are simulated using those tool
s. In LTE systems, the downlink scheduler is an
important component for radio resource management;
hence in the context of LTE simulation, a study
between the downlink scheduler models between the s
imulators are performed.
A Machine Learning based Network Sharing System Design with MPTCPIJMREMJournal
The information and communication technologies (ICT) integrate different types of wireless communication to
provide IT-enabled services and applications. The great majority end devices are equipped with multiple network
interfaces such as Wi-Fi and 4G. Our goal is to integrate the available network interfaces and technologies to
enhance seamless communication efficiency and increase resources utilization. We proposed a heterogeneous
network management algorithm based on machine learning methods which includes roaming and sharing
functions. The roaming function provides the multiple network resources in physical and media access control
layers. The sharing function supports multiple network resources allocation and the service handover process
based on the Multi-Path TCP protocol. The simulation result also shows that the proposed scheme can increase
the network bandwidth utilization effectively. The sharing system could be used in home, mobile and vehicular
environments to realize ubiquitous social sharing networks.
A Machine Learning based Network Sharing System Design with MPTCPIJMREMJournal
1) The document describes a machine learning-based network sharing system that uses Multipath TCP to integrate multiple network interfaces and allocate bandwidth resources for multiple users.
2) The system includes roaming and sharing functions, where roaming chooses the best network and sharing allocates resources across available networks.
3) A heterogeneous network management algorithm is proposed that monitors network status, predicts handovers between networks, and uses a machine learning approach to optimize resource utilization and load balancing across different network interfaces.
PERFORMANCE ANALYSIS OF RESOURCE SCHEDULING IN LTE FEMTOCELLS NETWORKScscpconf
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and time dimension. So several scheduling algorithms need to be analyzed for femtocells networks. In this paper we introduce a performance analysis of three distinct scheduling algorithms of mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in terms of throughput, packet loss ratio, fairness index and spectral efficiency.
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize
the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and
time dimension. So several scheduling algorithms need to be analyzed for femtocells networks.
In this paper we introduce a performance analysis of three distinct scheduling algorithms of
mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in
terms of throughput, packet loss ratio, fairness index and spectral efficiency.
A Case Study on Ip Based Cdma Ran by Controlling RouterIJERA Editor
As communication plays an important role in day to day life, the effective and efficient data transmission is to be maintained. This paper mainly deals with implements a congestion control mechanism using Router control method for IP-RAN on CDMA cellular network. The Router control mechanism uses the features of CDMA networks using active Queue Management technique to reduce delay and to minimize the correlated losses. When utilizing these new personal tools and services to enrich our lives, while being mobile, we are using Mobile Multimedia applications. As new handsets, new technologies and new business models are introduced on the marketplace, new attractive multimedia services can and will be launched, fulfilling the demands. Because the number of multimedia services and even more so, the context in which the services are used is numerous, the following model is introduced in order to simplify and clarify how different services will evolve, enrich our lives and fulfill our desires.The proposed paper work is to be realized using Matlab platform.
A CELLULAR BONDING AND ADAPTIVE LOAD BALANCING BASED MULTI-SIM GATEWAY FOR MO...pijans
As it is well known, the QoS(quality of service) provided by mobile Internet access point devices is far from
the QoS level offered by the common ADSL modem-router due to several reasons: in fact, mobile Internet
access networks are not designed to support real-time data traffic because of several drawbacks
concerning the wireless medium such as resource sharing, traffic congestion, radio link coverage etc.,
which impact directly such parameters as delay, jitter, and packet loss rate that are strictly connected to
the quality of user experience. The main scope of the present paper is to introduce a dual USIM HSPA
gateway for ad hoc and sensors networks thanks to which it will be possible to guarantee a QoS suitable
for a series of network-centric application such as real-time communications and monitoring, video
surveillance, real-time sensor networks, telemedicine, vehicular and mobile sensor networks and so on. The
main idea is to exploit multiple radio access networks in order to enhance the available end-to-end
bandwidth and the perceived quality of experience. The scope has been reached by combining multiple
radio access with dynamic load balancing and the VPN (virtual private network) bond technique.
A Cellular Bonding and Adaptive Load Balancing Based Multi-Sim Gateway for Mo...
Interactivity_NCC
1. Abstract: Mobile devices are currently used not only
for two-way voice/data/video communication, but also
as wireless internet terminals. The power of
interactivity lies in the reciprocal process of
information exchange between two or more users and
an interactive service allows users to shop, vote, play
games, conduct financial transactions, reserve
holidays/ tickets and so on. This article highlights
importance and challenges of incorporating
“interactivity” in mobile multimedia system. Then,
various solutions (e.g., Hybrid-ARQ in Node B,
shorter transmit-time-interval, Node B-controlled
scheduling and adaptive modulation-and-coding) for
implementing interactivity are explained. Finally,
Node B-introduced ARQ and scheduling are examined
from a mobile system-standpoint to understand how
the solutions provide fast interactivity.
1 Importance of “Interactivity”
Mobile devices have allowed people across globe to
have two-way voice/data/video communication in a
tetherless manner. Use of the internet through mobile
terminals is also increasing rapidly throughout the
world. Mobile phones have evolved into wireless
internet terminals, enriching people's lives by letting
them acquire any type of information, whenever they
want. An interactive service allows users to shop, vote,
bet, play games, conduct financial transactions,
send/receive emails, book holidays/ tickets and so on
and so forth. Thus, “interactivity” plays a key role in
people-to-device dialog and makes a user active
participant in the process.
The power of interactivity lies in the reciprocal process
of information exchange between two or more
"players" in communication. "Players" can be pupils,
facilitators, peers but can also be automated learning
resources and other databases. Order-entry and many
other business applications need interactivity in a
limited way whereas mobile gaming requires
significant interactivity. In general, faster response and
interactivity provide a great deal of advantages through
(i) quick-and-better decision-making, (ii) easy
learning, (iii) on-demand request-servicing and (iv)
entertainment.
In Section 2, we outline challenges of implementing
“interactivity” feature. In Section 3, we discuss various
solutions to support “interactivity” in mobile
multimedia system. In Section 4, we explain how these
solutions facilitate providing “interactivity” feature in
next-generation mobile system. Section 5 concludes
the article.
2 Challenges of Incorporating “Interactivity”
As the applications using interactivity become more
demanding in terms of data rate and response-time,
there is an increasing need to improve system capacity,
enhance throughput and reduce overall communication
delay. At the same time, specific application and user
expectation are also important attributes to decide
whether the available data rate and responsiveness are
sufficient for provisioning interactivity. The meaning
of “interactivity” for a mobile user accessing
transactional information using SMS will definitely be
very different than a user playing network-based
mobile game.
In a typical 3G mobile system, radio access layer (as
specified in 3GPP Release 4) enables interactivity.
Fig.1 shows how communication takes place between
radio-link control (RLC) layer of user equipment (UE)
and RLC in the radio network controller (RNC)-side.
Large round-trip delay due to RLC retransmissions of
erroneously received data makes the system slow. This
does not support the delay-sensitive applications even
the data rate is not a constraint.
‘Interactivity’ in Mobile Multimedia Systems
Manoj Kumar(manoj-dsp.kumar@st.com), Alok Mehta, Kapil Soni and Aloknath De,
STMicroelectronics India
2. Figure 1: Radio Interface Protocol (3GPP Release 4)
Thus, a continuous need for even better spectral
efficiencies, reduced round-trip delay, improved user
experiences and new services is driving the
standardization of new features in mobile multimedia
systems.
3 Solutions to Support Interactivity
In order to meet the challenges discussed in Section 2,
the existing technology needs to be evolved for
increasing the system capacity and reducing the round-
trip delay. Increased system capacity will help to
provide higher data-rates and/or serve more number of
users. A large (e.g., 10 ms) Transmission Time
Interval (TTI refers to time-interval at which higher
layer provides data blocks to physical layer) and Radio
Link Control (RLC) layer-embedded ARQ protocol
makes the round-trip delay large in mobile systems
(ref: 3GPP Release 4). Hence, to reduce the round-trip
delay, a shorter TTI and an ARQ mechanism at the
NodeB level (Hybrid-ARQ) have been introduced.
This increases the system throughput also. In addition
to the above techniques, NodeB-controlled scheduling
of users and adaptive modulation-and-coding (AMC)
have also been introduced. These help in handling the
bursty traffic efficiently and enhancing the system
capacity/throughput. To implement Hybrid-ARQ and
NodeB-controlled scheduling, MAC functionality is
required to be placed partially at NodeB as shown in
Fig.2. Details of the schemes are given in the
following sub-sections.
Figure 2: Radio Interface Protocol (ref: 3GPP)
3.1 Hybrid ARQ in NodeB
A mix of forward error-correction (FEC) and
automatic repeat request (ARQ) is used to get reliable
and efficient communication over noisy channels.
ARQ ensures very low undetected error probability by
increasing the number of re-transmissions. On the
other hand, FEC corrects any error introduced due to
noisy channel and thus reduces the number of re-
transmissions. NodeB Hybrid-ARQ (HARQ) allows
rapid re-transmissions of erroneously received data
units. Since re-transmissions happen from NodeB (and
not every time from RNC), it reduces the number of
RLC retransmissions and the associated delays. This
definitely improves the quality-of-service (QoS)
experienced by the end user. As a NodeB-controlled
re-transmission is less costly from a delay perspective,
the physical channel can be operated with somewhat
higher error probability than in the system not
employing NodeB Hybrid-ARQ. This results in
improved system capacity. Soft combining can further
improve the performance of a Node B Hybrid ARQ
mechanism.
3.2 Reduction of Minimum TTI
Size of frame at the air interface, which equals the
minimum TTI, directly adds to the round-trip delay.
Thus, reducing the minimum TTI from 10ms to a
lower value (say, 2 ms, an optimal value considering
tradeoff between frame overheads and delay) will
reduce the transfer delay due to reduction of air-
interface delay and delay due to TTI alignment
(incoming data to be transmitted has to wait until the
start of the next TTI). A shorter TTI also helps to
reduce processing time of payload and round-trip delay
in Node B Hybrid-ARQ protocols, thus, resulting in a
higher system throughput and better resource
utilization.
RLC
UE NodeB RNC
IubUu
PHY
RLC
MAC
PHY TNL TNL
MAC
Shorter Round
trip delay path for
Hybrid ARQ
Partial
MAC
UE NodeB RNC
IubUu
PHY
RLC
MAC
PHY TNL TNL
MAC
RLC
Round trip delay
path for RLC
based ARQ
RNC – Radio Network Controller
RLC – Radio Link Control layer
MAC – Medium Access Control layer
PHY – Physical layer
TNL – Transport Network layer
Uu – WCDMA Radio Interface
Iub – Interface between NodeB and RNC
3. 3.3 NodeB-Controlled Scheduling
For distributing the system capacity and the available
power among all users in an optimal way, resource
scheduling needs to be done properly. Traditionally,
user scheduling is done by RNC on the basis of
channel conditions. This causes slow adaptation to the
changed channel conditions. Now, NodeB is given the
scheduling capability which ensures faster adaptation
to the channel conditions of each user.
In Fig.3., UE maintains a table containing all possible
Transport Format Combinations (TFCs) configured by
RNC. TFC quantifies the data which needs to be
processed by UE in a single TTI. This complete set of
TFCs is called Transport Format Combination Set
(TFCS). Traditionally, UE chooses the TFC from this
whole TFCS. However in NodeB-controlled
scheduling, a subset is defined by NodeB within TFCS
so that UE is restricted to choose TFC from NodeB-
defined TFC subset. NodeB can further update the
subset as per the interference and user buffer
information. This tighter control of uplink interference
results in increased capacity and improved coverage.
Node B controlled
TFC subset
TFCS configured
by RNC
Minimum SetTFC
TFC
TFC
TFC
TFC
TFC
TFC
TFC
TFC
TFC
Figure 3: Configuration of TFCs table at UE
In the downlink, the users are scheduled using the
various packet scheduling algorithms (based on
Channel Quality) which are as follows:
- Round Robin: The users are being served in a
cyclic order ignoring the channel quality
conditions.
- Fair Throughput: It provides a same
throughput distribution among the users.
- C/I Based: Scheduling strategies based on C/I
policy favour users with the best channel
conditions.
3.4 Adaptive Modulation and Coding (AMC)
The benefits of adapting the transmission parameters
to the changing channel conditions of a wireless
system are well-known. In fact, fast power control is
an example of a technique implemented to enable
reliable communications, while simultaneously
improving system capacity. The process of modifying
the transmission parameters to compensate for the
variations in channel conditions is known as link
adaptation. Another technique that falls under this
category is adaptive modulation and coding (AMC).
The principle of AMC is to change the modulation and
coding format in accordance with variations in the
channel conditions, subject to system restrictions. The
channel conditions can be estimated e.g. based on
feedback from the receiver. In a system with AMC,
users in favorable positions, e.g., users close to the cell
site are typically assigned higher-order modulation
with higher code-rates (e.g., 64-QAM with R=3/4
Turbo Codes), while users in unfavorable positions
e.g., users close to the cell boundary, are assigned
lower-order modulation with lower code-rates (e.g.,
QPSK with R=1/2 Turbo Codes). The main benefits
of AMC are: a) availability of higher data-rates for
users in favorable positions which in turn increases the
average throughput of the cell, and b) reduced
interference variation due to link adaptation based on
variations in the modulation/coding scheme instead of
variations in transmit power.
4 System Analysis
Let us consider the example of world-wide-web access
through mobile phones. We not only interact with the
web browser, but also with the pages that the browser
brings to us. The implicit invitations called hypertext
that link us to other pages provide the most common
form of interactivity when using the web. This can
then be thought of as a giant, interconnected
application program. Let us now investigate the impact
of techniques on the complete UMTS system. As our
focus is on NodeB sub-system, discussion will explore
the system aspect at NodeB level primarily.
4.1 Intelligent Node-B and System Complexity
By embedding intelligence in NodeB, it has been given
the capability to detect error(s) in received data frames
and accordingly take action (sending ACK/NACK to
UE for uplink). It also receives the ACK/NACK
corresponding to the frames sent to the UE in
4. downlink and retransmits the frames erroneously
received by UE. Scheduling functionality has also
been partially shifted from RNC-MAC to NodeB.
These added functionalities make NodeB more
complex and require extra amount of processing
power. As the round-trip delay also constitutes the
NodeB decoding time, it is imperative to reduce the
processing time. For implementation, a more complex
NodeB requires high processing CPUs and DSPs,
sufficient on-chip memory, and fast off-chip memory.
4.2 Performance of RNC Vs NodeB Scheduling
In centralized scheduling, the scheduler is located in
RNC, and is responsible for simultaneous scheduling
of UEs across multiple cells. Thus, it is possible to
take into account the impact of each scheduled UE in
all cells of its active set. However, the drawback of
such scheme is the significant scheduling delay. To
reduce the scheduling delays and take advantage of the
possible fast scheduling gains, NodeB scheduling is
needed. In this case, the scheduling is decentralized as
the knowledge of the received signal level is available
only at the scheduling NodeB and each NodeB
schedules the UEs without considering their
contribution to the other cells. Hence, there is an
advantage of the decentralized scheduling over the
centralized scheduling due to the shorter delays
incurred in the scheduling process and the possibility
of exploiting the fast scheduling gain. However, the
lack of knowledge of the impact an UE may have on
the other cells’ rise-over-thermal noise (RoT) is a
disadvantage.
The objective is to determine the loss due to the partial
information availability in the decentralized scheduler,
without exploiting any possible fast scheduling gains,
and form a benchmark for the gains needed to be
provided by faster scheduling. Based on the simulation
results it can be seen that for the same average RoT,
the centralized scheduler yields a throughput gain over
the decentralized scheduler. Also, while the fairness
remains the same, the RoT overshoot (Probability
{RoT > 7dB}) is higher in the case of decentralized
scheduling. This degradation represents the minimum
benchmark for the gains to be provided by faster
scheduling and other techniques that rely on faster
scheduling.
4.3 HARQ Efficiency Vs Block Error Rate
(BLER) operation point
To evaluate the efficiency of HARQ the BLER for the
first transmission should be a non zero value. HARQ
efficiency increases as the BLER is increased.
However from complexity point of view, the increase
of BLER operation point (to 50% or even higher) also
means complexity increase. If the first transmission
BLER is high and the single user throughput is kept
the same, then the peak data rate has to be increased.
This signifies allocation of more hardware and/or
software resources for each user both at UE and radio
network side. On the other hand, if single user
throughput is allowed to decrease and the system
throughput is increased by allowing more users in the
cell, it requires more hardware and/or software
resources in the network side.
The amount of Iub traffic and buffering and processing
at RNC is increased if the reordering is performed at
RNC. Roughly speaking, BLER=50-60% operation
point requires that the baseband buffers and amount of
processing resources are doubled compared to
BLER=10% operation point. The higher peak data rate
per user or more users both imply that the amount of
processing and the amount of buffering need to be
increased at Node B.
5 Concluding Remarks
Order-entry and other business applications need
interactivity in a limited way, whereas video
streaming, mobile gaming, virtual office, tele-learning
and similar applications require significant
interactivity. In general, faster response and
interactivity provide a great deal of advantages through
quick-and-better decision-making, easy learning, on-
demand request-servicing and entertainment. In this
article, various solutions (e.g., Hybrid-ARQ in Node
B, shorter transmit-time-interval, Node B-controlled
scheduling and adaptive modulation-and-coding) for
implementing interactivity have been explained
independently as well as with reference to a mobile
system. Pens, thumb/phone keyboards, touch screens,
etc. may be appended to mobile multimedia systems so
as to provide user interface for proper interactivity.
REFERENCES
[1] 3GPP TR 25.896 v6.0.0 (2004-03), Feasibility
Study for Enhanced Uplink for UTRA FDD
[2] 3GPP TR 25.848 v4.0.0 (2001-03), Physical Layer
Aspects of UTRA High Speed Downlink Packet
Access