The document provides an overview of mobility management in wireless networks. It discusses radio mobility and network mobility, and key aspects like location management, registration, and handoff. Mobility management functions aim to enable subscriber mobility through tracking location and delivering calls. Location is tracked through registering with location areas and updating on area crossings. Handoff allows maintaining connections as subscribers move between cells.
IS-95 CDMA is an air interface standard that uses code division multiple access (CDMA). It employs various techniques to improve system capacity and performance, including bandwidth recycling, power control, soft handoffs, diversity combining, and variable rate vocoding. Key aspects of IS-95 include the use of quadrature phase shift keying modulation at a 1.2288 Mcps chip rate, forward error correction coding, and multiple logical channels (pilot, sync, paging, traffic) defined using orthogonal Walsh codes.
The document discusses CDMA2000, a 3G cellular technology that provides an evolutionary upgrade path from 2G CDMA. It spreads signals across 1.25MHz of spectrum to transmit uniquely encoded signals simultaneously. CDMA2000 supports high-speed packet data through standards like 1X EV-DO that enable up to 2.4Mbps speeds. While it offers advantages like efficient spectrum use and support for advanced services, disadvantages include potential channel pollution from multiple signals and limited international roaming without multimode devices.
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
Physical channels carry information over the air interface between the mobile station and base transceiver station. Logical channels map user data and signaling information onto physical channels. There are two main types of logical channels - traffic channels which carry call data, and control channels which communicate service information. Control channels include broadcast channels which transmit cell-wide information, common channels used for paging and access procedures, and dedicated channels for signaling during calls or when not on a call. Logical channels are mapped onto physical channels to effectively transmit information wirelessly between network components in a GSM system.
Cellular systems allow mobile users to communicate wirelessly using a network of base stations and switches. A mobile station communicates with the nearest base station, which connects to a mobile switching center. The switching center routes calls between mobile stations and the public switched telephone network. Coverage areas are divided into cells served by individual base stations to allow frequency reuse that improves system capacity.
The document is a seminar report on Wideband Code Division Multiple Access (WCDMA) technology. It discusses the basics of WCDMA, including that it uses code division multiple access to separate users and spread signals over a wide 5MHz bandwidth. It also covers WCDMA specifications, generation, spreading principles, power control, handovers, and advantages such as service flexibility and spectrum efficiency.
Handovers, also called handoffs, allow mobile users to maintain connectivity as they move between different cells. They involve transferring control of a call or data session from one cell to another. There are different types of handovers in GSM including intra-BTS, inter-BTS intra-BSC, inter-BSC, and inter-MSC handovers. Factors like transmitted power, received power, area and shape of cells, and user mobility affect the handover process.
IS-95 CDMA is an air interface standard that uses code division multiple access (CDMA). It employs various techniques to improve system capacity and performance, including bandwidth recycling, power control, soft handoffs, diversity combining, and variable rate vocoding. Key aspects of IS-95 include the use of quadrature phase shift keying modulation at a 1.2288 Mcps chip rate, forward error correction coding, and multiple logical channels (pilot, sync, paging, traffic) defined using orthogonal Walsh codes.
The document discusses CDMA2000, a 3G cellular technology that provides an evolutionary upgrade path from 2G CDMA. It spreads signals across 1.25MHz of spectrum to transmit uniquely encoded signals simultaneously. CDMA2000 supports high-speed packet data through standards like 1X EV-DO that enable up to 2.4Mbps speeds. While it offers advantages like efficient spectrum use and support for advanced services, disadvantages include potential channel pollution from multiple signals and limited international roaming without multimode devices.
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
Physical channels carry information over the air interface between the mobile station and base transceiver station. Logical channels map user data and signaling information onto physical channels. There are two main types of logical channels - traffic channels which carry call data, and control channels which communicate service information. Control channels include broadcast channels which transmit cell-wide information, common channels used for paging and access procedures, and dedicated channels for signaling during calls or when not on a call. Logical channels are mapped onto physical channels to effectively transmit information wirelessly between network components in a GSM system.
Cellular systems allow mobile users to communicate wirelessly using a network of base stations and switches. A mobile station communicates with the nearest base station, which connects to a mobile switching center. The switching center routes calls between mobile stations and the public switched telephone network. Coverage areas are divided into cells served by individual base stations to allow frequency reuse that improves system capacity.
The document is a seminar report on Wideband Code Division Multiple Access (WCDMA) technology. It discusses the basics of WCDMA, including that it uses code division multiple access to separate users and spread signals over a wide 5MHz bandwidth. It also covers WCDMA specifications, generation, spreading principles, power control, handovers, and advantages such as service flexibility and spectrum efficiency.
Handovers, also called handoffs, allow mobile users to maintain connectivity as they move between different cells. They involve transferring control of a call or data session from one cell to another. There are different types of handovers in GSM including intra-BTS, inter-BTS intra-BSC, inter-BSC, and inter-MSC handovers. Factors like transmitted power, received power, area and shape of cells, and user mobility affect the handover process.
This document summarizes key concepts in propagation models for wireless mobile communications. It discusses free space losses, plane earth losses, and models for the wireless channel including macrocells, shadowing, narrowband fast fading, and wideband fast fading. Empirical and physical statistical models are described for modeling propagation in different environments like urban, suburban, and rural areas. Deterministic and statistical models are presented for modeling narrowband fast fading effects.
The document discusses power control in 3G networks. It describes the need for power control to address the near-far effect in cellular systems and reduce interference. There are two main types of power control: inner loop power control, which operates fast to compensate for fading and distance, and outer loop power control, which operates slower to maintain signal quality. Inner loop power control can be open-loop, where the transmitting device adjusts its power, or closed-loop, where the receiving device provides feedback to adjust transmission power.
Wireless local loop (WLL) provides wireless connections for stationary users as an alternative to wired connections. It targets the "last mile" between a neighborhood access point and end users. Key advantages include lower installation costs than wiring due to reduced digging and infrastructure requirements, as well as rapid deployment. WLL systems face challenges around spectrum licensing, maintaining wireline-level service quality, and planning networks to achieve high penetration levels while supporting limited user mobility within coverage areas. Common WLL technologies include cellular, satellite, and fixed wireless access using licensed or unlicensed spectrum.
Topics covered in this presentation:
1. RF spectrum and GSM specifications
2. FDMA and TDMA
3. Digital Voice Transmission
4. Channel coding, Interleaving and Burst formatting
5. GMSK
6. Frame structure of GSM
7. Corrective actions against multipath fading
Universal mobile telecommunication System (UMTS) is actually the third generation mobile, which uses WCDMA. The Dream was that 2G and 2.5G systems are incompatible around the world.
-Worldwide devices need to have multiple technologies inside of them, i.e. tri-band phones, dual-mode phones
To develop a single standard that would be accepted around the world.
-One device should be able to work anywhere.
Increased data rate.
- Maximum 2048Kbps
UMTS is developed by 3GPP (3 Generation Partnership Project) a joint venture of several organization
3G UMTS is a third-generation (3G): broadband, packet-based transmission of text, digitized voice, video, multimedia at data rates up to 2 Mbps
Also referred to as wideband code division multiple access(WCDMA)
Allows many more applications to be introduce to a worldwide
Also provide new services like alternative billing methods or calling plans.
The higher bandwidth also enables video conferencing or IPTV.
Once UMTS is fully available, computer and phone users can be constantly attached to the Internet wherever they travel and, as they roam, will have the same set of capabilities.
Today's cellular telephone systems operate by dividing geographic areas into cells served by base stations. Each cell is assigned certain radio frequencies that are reused in non-neighboring cells to increase coverage and capacity. When a mobile user moves between cells, the call is handed off from one base station to another through a mobile switching center to avoid disconnection. Modern cellular networks use digital technologies like CDMA, TDMA and FDMA to provide voice, text, and data services to users through cellular infrastructure.
cellular concepts in wireless communicationasadkhan1327
The document discusses the concept of frequency reuse in cellular networks. It explains that a limited radio spectrum is used to serve millions of subscribers by dividing the network coverage area into cells and reusing frequencies across spatially separated cells. Each cell is allocated a portion of the total available frequencies, and neighboring cells are assigned different frequencies to minimize interference. The frequency reuse factor is defined as the ratio of the minimum distance between co-channel cells to the cell radius. Larger frequency reuse factors provide better isolation between co-channel cells but reduce network capacity. The document also covers additional topics like different channel assignment strategies, handoff methods, interference calculation and optimization of frequency reuse networks.
This document discusses handoff in mobile communication networks. It begins with defining handoff as the transition of signal transmission from one base station to an adjacent one as a user moves. It then discusses various handoff strategies such as prioritizing handoff calls over new calls, monitoring signal strength to avoid unnecessary handoffs, and reserving guard channels for handoff requests. The document also covers types of handoffs, how handoff is handled differently in 1G and 2G cellular systems, challenges like cell dragging, and concepts like umbrella cells to minimize handoffs for high-speed users.
GENERAL DESCRIPTION OF THE PROBLEM , CONCEPT OF FREQUENCY CHANNELS, CO-CHANNEL iNTERFERENCE REDUCTION FACTOR , DESIRED C/I FROM A NORMAL CASE IN A OMNI DIRECTIONAL ANTENNA SYSTEM , CELL SPLITTING , CONSIDERATION OF THE COMPONENTS OF CELLULAR SYSTEM.
This document discusses radio channels and interfaces in GSM networks. It covers topics like:
- The Um interface between the mobile station and base station subsystem.
- Processing of the voice signal from analog to digital conversion through encoding, interleaving and modulation for transmission.
- The different types of radio channels used including traffic channels, control channels, and their logical and physical combinations in bursts and frames.
- Technologies used for efficient transmission like frequency hopping, discontinuous transmission, and power control.
This document discusses support for mobility in mobile communications. It covers file systems, databases, the World Wide Web, and the Wireless Application Protocol (WAP). For file systems, it describes challenges like limited resources, bandwidth issues, and inconsistency problems in mobile environments. It also summarizes several experimental file systems that use techniques like caching, pre-fetching, and weak consistency models. For databases, it notes issues like location-dependent queries and transaction processing challenges. For the WWW, it outlines problems of HTTP and HTML on mobile devices and approaches to address them. It provides an overview of the WAP standard and its goals of delivering Internet content and services to mobile devices.
Improving coverage and capacity in cellular systemsTarek Nader
Cellular networks use various techniques to expand coverage and increase capacity as needs change over time, including cell splitting, beam tilting, cell sectoring, microcells, and frequency borrowing. Cell splitting involves dividing larger cells into smaller cells served by lower-power base stations to enable more spatial frequency reuse and greater system capacity, though it increases handoffs and costs. Beam tilting reduces interference between cells by tilting antenna beams downward. Cell sectoring divides cells into wedge-shaped sectors each with their own channels to decrease interference while reducing trunking efficiency. Microcells add capacity in hotspot areas without changing reuse factors. Frequency borrowing assigns congested cells frequencies from adjacent cells dynamically.
Introduction to Cellular Mobile System,
Performance criteria,
uniqueness of mobile radio environment,
operation of cellular systems,
Hexagonal shaped cells,
Analog Cellular systems.
Digital Cellular systems
This document discusses synchronization in mobile computing systems. It describes how data is replicated and distributed across mobile devices, personal computers, and remote servers. It then discusses various synchronization techniques used to maintain consistency between distributed copies of data, including one-way synchronization initiated by the server or client, two-way synchronization, and refresh synchronization. The document also covers domain-specific rules that govern how data is synchronized across different platforms and data formats.
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
The document discusses several advantages of CDMA technology, including frequency reuse, large coverage area, high spectrum capacity, privacy, soft handoff, good voice quality, and smooth migration to 3G. It also provides details on ZTE's involvement with CDMA technology development and key components of a CDMA network such as the BSC, BTS, MSC, VLR, and HLR.
The document provides an overview of GSM architecture including:
1. GSM uses a cellular network architecture with base stations, base station controllers, mobile switching centers, and databases to manage subscriber identity and location.
2. The network allows for voice calls and data services including SMS, and provides security through subscriber authentication and encryption.
3. GSM is a global standard that enabled international roaming and continues to evolve to support higher data rates through technologies like GPRS, EDGE, and WCDMA.
The document discusses equalization techniques used to mitigate inter-symbol interference (ISI) in digital communication systems. Equalization aims to remove ISI and noise effects from the channel. It is located at the receiver and uses techniques like linear equalizers, decision feedback equalization, and maximum likelihood sequence estimation to estimate the channel response and minimize the error between transmitted and received symbols while balancing noise. As the wireless channel changes over time, adaptive equalization is used where the equalizer periodically trains and tracks the changing channel response.
The document describes the architecture of GSM networks. It discusses the key components including the mobile station, base station subsystem (BSS), and network subsystem (NSS). The mobile station consists of mobile equipment and a subscriber identity module (SIM) card. The BSS comprises base transceiver stations and a base station controller. The NSS combines switches like the mobile switching center with databases like the home location register and visitor location register that track subscriber locations and identities.
Introduction To Wireless Fading ChannelsNitin Jain
The document summarizes key concepts related to wireless fading channels, including:
1. Multipath fading causes fluctuations in signal strength over small physical distances due to constructive and destructive interference from multiple signal paths.
2. Rayleigh fading occurs when there is no line-of-sight path between transmitter and receiver, resulting in fast, large fluctuations in signal strength over small physical distances.
3. Doppler spread and coherence time describe how quickly the wireless channel varies over time due to mobility, with fast fading occurring if the channel changes significantly within a symbol period.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
A Comparative Study on Profile Based Location Management for Personal Communi...IJERA Editor
Location of the mobile user is registered to the two databases for call tracking and those registration processes
basis much network traffic. By this speed of Call delivery reduced and location updating cost improved. In this
paper, the first method a new meek location management by registering Representative VLR of group of certain
VLRs regionally and broadcasting for searching a mobile user, so called rVLR-B.This The representative VLR
of several VLRs and register mobile users’ location. When set up the call path between mobile users, the VLR
of the caller inquiries callee’s rVLR for searching the location of callee instead of demanding to VLR of callee.
And then rVLR broadcast the callee’s location to all VLR of the region simultaneously. Location registration is
only performed when a mobile user visits a new rVLR network area from present area. Using the rVLR-B, the
cost of maintaining location of mobile users was abridged. The second technique for reducing the costs during
the location tracking and location update is proposed. Taking the regular movement pattern of the users it
produces the block and the user registers with the HLR only after crossing the block instead of crossing the
single cell. The block register (BR) is introduced between the block and the HLR in two level systems to
preserve the blocks, thus creates three level architecture. In this architecture some signaling cost values between
the MSC-BR, BRHLR and BR-BR are maintained to get the better enactment. By the rVLR-B and BR the
performance of speed of call delivery improved and location updation will be diminished
This document summarizes key concepts in propagation models for wireless mobile communications. It discusses free space losses, plane earth losses, and models for the wireless channel including macrocells, shadowing, narrowband fast fading, and wideband fast fading. Empirical and physical statistical models are described for modeling propagation in different environments like urban, suburban, and rural areas. Deterministic and statistical models are presented for modeling narrowband fast fading effects.
The document discusses power control in 3G networks. It describes the need for power control to address the near-far effect in cellular systems and reduce interference. There are two main types of power control: inner loop power control, which operates fast to compensate for fading and distance, and outer loop power control, which operates slower to maintain signal quality. Inner loop power control can be open-loop, where the transmitting device adjusts its power, or closed-loop, where the receiving device provides feedback to adjust transmission power.
Wireless local loop (WLL) provides wireless connections for stationary users as an alternative to wired connections. It targets the "last mile" between a neighborhood access point and end users. Key advantages include lower installation costs than wiring due to reduced digging and infrastructure requirements, as well as rapid deployment. WLL systems face challenges around spectrum licensing, maintaining wireline-level service quality, and planning networks to achieve high penetration levels while supporting limited user mobility within coverage areas. Common WLL technologies include cellular, satellite, and fixed wireless access using licensed or unlicensed spectrum.
Topics covered in this presentation:
1. RF spectrum and GSM specifications
2. FDMA and TDMA
3. Digital Voice Transmission
4. Channel coding, Interleaving and Burst formatting
5. GMSK
6. Frame structure of GSM
7. Corrective actions against multipath fading
Universal mobile telecommunication System (UMTS) is actually the third generation mobile, which uses WCDMA. The Dream was that 2G and 2.5G systems are incompatible around the world.
-Worldwide devices need to have multiple technologies inside of them, i.e. tri-band phones, dual-mode phones
To develop a single standard that would be accepted around the world.
-One device should be able to work anywhere.
Increased data rate.
- Maximum 2048Kbps
UMTS is developed by 3GPP (3 Generation Partnership Project) a joint venture of several organization
3G UMTS is a third-generation (3G): broadband, packet-based transmission of text, digitized voice, video, multimedia at data rates up to 2 Mbps
Also referred to as wideband code division multiple access(WCDMA)
Allows many more applications to be introduce to a worldwide
Also provide new services like alternative billing methods or calling plans.
The higher bandwidth also enables video conferencing or IPTV.
Once UMTS is fully available, computer and phone users can be constantly attached to the Internet wherever they travel and, as they roam, will have the same set of capabilities.
Today's cellular telephone systems operate by dividing geographic areas into cells served by base stations. Each cell is assigned certain radio frequencies that are reused in non-neighboring cells to increase coverage and capacity. When a mobile user moves between cells, the call is handed off from one base station to another through a mobile switching center to avoid disconnection. Modern cellular networks use digital technologies like CDMA, TDMA and FDMA to provide voice, text, and data services to users through cellular infrastructure.
cellular concepts in wireless communicationasadkhan1327
The document discusses the concept of frequency reuse in cellular networks. It explains that a limited radio spectrum is used to serve millions of subscribers by dividing the network coverage area into cells and reusing frequencies across spatially separated cells. Each cell is allocated a portion of the total available frequencies, and neighboring cells are assigned different frequencies to minimize interference. The frequency reuse factor is defined as the ratio of the minimum distance between co-channel cells to the cell radius. Larger frequency reuse factors provide better isolation between co-channel cells but reduce network capacity. The document also covers additional topics like different channel assignment strategies, handoff methods, interference calculation and optimization of frequency reuse networks.
This document discusses handoff in mobile communication networks. It begins with defining handoff as the transition of signal transmission from one base station to an adjacent one as a user moves. It then discusses various handoff strategies such as prioritizing handoff calls over new calls, monitoring signal strength to avoid unnecessary handoffs, and reserving guard channels for handoff requests. The document also covers types of handoffs, how handoff is handled differently in 1G and 2G cellular systems, challenges like cell dragging, and concepts like umbrella cells to minimize handoffs for high-speed users.
GENERAL DESCRIPTION OF THE PROBLEM , CONCEPT OF FREQUENCY CHANNELS, CO-CHANNEL iNTERFERENCE REDUCTION FACTOR , DESIRED C/I FROM A NORMAL CASE IN A OMNI DIRECTIONAL ANTENNA SYSTEM , CELL SPLITTING , CONSIDERATION OF THE COMPONENTS OF CELLULAR SYSTEM.
This document discusses radio channels and interfaces in GSM networks. It covers topics like:
- The Um interface between the mobile station and base station subsystem.
- Processing of the voice signal from analog to digital conversion through encoding, interleaving and modulation for transmission.
- The different types of radio channels used including traffic channels, control channels, and their logical and physical combinations in bursts and frames.
- Technologies used for efficient transmission like frequency hopping, discontinuous transmission, and power control.
This document discusses support for mobility in mobile communications. It covers file systems, databases, the World Wide Web, and the Wireless Application Protocol (WAP). For file systems, it describes challenges like limited resources, bandwidth issues, and inconsistency problems in mobile environments. It also summarizes several experimental file systems that use techniques like caching, pre-fetching, and weak consistency models. For databases, it notes issues like location-dependent queries and transaction processing challenges. For the WWW, it outlines problems of HTTP and HTML on mobile devices and approaches to address them. It provides an overview of the WAP standard and its goals of delivering Internet content and services to mobile devices.
Improving coverage and capacity in cellular systemsTarek Nader
Cellular networks use various techniques to expand coverage and increase capacity as needs change over time, including cell splitting, beam tilting, cell sectoring, microcells, and frequency borrowing. Cell splitting involves dividing larger cells into smaller cells served by lower-power base stations to enable more spatial frequency reuse and greater system capacity, though it increases handoffs and costs. Beam tilting reduces interference between cells by tilting antenna beams downward. Cell sectoring divides cells into wedge-shaped sectors each with their own channels to decrease interference while reducing trunking efficiency. Microcells add capacity in hotspot areas without changing reuse factors. Frequency borrowing assigns congested cells frequencies from adjacent cells dynamically.
Introduction to Cellular Mobile System,
Performance criteria,
uniqueness of mobile radio environment,
operation of cellular systems,
Hexagonal shaped cells,
Analog Cellular systems.
Digital Cellular systems
This document discusses synchronization in mobile computing systems. It describes how data is replicated and distributed across mobile devices, personal computers, and remote servers. It then discusses various synchronization techniques used to maintain consistency between distributed copies of data, including one-way synchronization initiated by the server or client, two-way synchronization, and refresh synchronization. The document also covers domain-specific rules that govern how data is synchronized across different platforms and data formats.
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
The document discusses several advantages of CDMA technology, including frequency reuse, large coverage area, high spectrum capacity, privacy, soft handoff, good voice quality, and smooth migration to 3G. It also provides details on ZTE's involvement with CDMA technology development and key components of a CDMA network such as the BSC, BTS, MSC, VLR, and HLR.
The document provides an overview of GSM architecture including:
1. GSM uses a cellular network architecture with base stations, base station controllers, mobile switching centers, and databases to manage subscriber identity and location.
2. The network allows for voice calls and data services including SMS, and provides security through subscriber authentication and encryption.
3. GSM is a global standard that enabled international roaming and continues to evolve to support higher data rates through technologies like GPRS, EDGE, and WCDMA.
The document discusses equalization techniques used to mitigate inter-symbol interference (ISI) in digital communication systems. Equalization aims to remove ISI and noise effects from the channel. It is located at the receiver and uses techniques like linear equalizers, decision feedback equalization, and maximum likelihood sequence estimation to estimate the channel response and minimize the error between transmitted and received symbols while balancing noise. As the wireless channel changes over time, adaptive equalization is used where the equalizer periodically trains and tracks the changing channel response.
The document describes the architecture of GSM networks. It discusses the key components including the mobile station, base station subsystem (BSS), and network subsystem (NSS). The mobile station consists of mobile equipment and a subscriber identity module (SIM) card. The BSS comprises base transceiver stations and a base station controller. The NSS combines switches like the mobile switching center with databases like the home location register and visitor location register that track subscriber locations and identities.
Introduction To Wireless Fading ChannelsNitin Jain
The document summarizes key concepts related to wireless fading channels, including:
1. Multipath fading causes fluctuations in signal strength over small physical distances due to constructive and destructive interference from multiple signal paths.
2. Rayleigh fading occurs when there is no line-of-sight path between transmitter and receiver, resulting in fast, large fluctuations in signal strength over small physical distances.
3. Doppler spread and coherence time describe how quickly the wireless channel varies over time due to mobility, with fast fading occurring if the channel changes significantly within a symbol period.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
A Comparative Study on Profile Based Location Management for Personal Communi...IJERA Editor
Location of the mobile user is registered to the two databases for call tracking and those registration processes
basis much network traffic. By this speed of Call delivery reduced and location updating cost improved. In this
paper, the first method a new meek location management by registering Representative VLR of group of certain
VLRs regionally and broadcasting for searching a mobile user, so called rVLR-B.This The representative VLR
of several VLRs and register mobile users’ location. When set up the call path between mobile users, the VLR
of the caller inquiries callee’s rVLR for searching the location of callee instead of demanding to VLR of callee.
And then rVLR broadcast the callee’s location to all VLR of the region simultaneously. Location registration is
only performed when a mobile user visits a new rVLR network area from present area. Using the rVLR-B, the
cost of maintaining location of mobile users was abridged. The second technique for reducing the costs during
the location tracking and location update is proposed. Taking the regular movement pattern of the users it
produces the block and the user registers with the HLR only after crossing the block instead of crossing the
single cell. The block register (BR) is introduced between the block and the HLR in two level systems to
preserve the blocks, thus creates three level architecture. In this architecture some signaling cost values between
the MSC-BR, BRHLR and BR-BR are maintained to get the better enactment. By the rVLR-B and BR the
performance of speed of call delivery improved and location updation will be diminished
A Comparative Study on Profile Based Location Management for Personal Communi...IJERA Editor
Location of the mobile user is registered to the two databases for call tracking and those registration processes basis much network traffic. By this speed of Call delivery reduced and location updating cost improved. In this paper, the first method a new meek location management by registering Representative VLR of group of certain VLRs regionally and broadcasting for searching a mobile user, so called rVLR-B.This The representative VLR of several VLRs and register mobile users’ location. When set up the call path between mobile users, the VLR of the caller inquiries callee’s rVLR for searching the location of callee instead of demanding to VLR of callee. And then rVLR broadcast the callee’s location to all VLR of the region simultaneously. Location registration is only performed when a mobile user visits a new rVLR network area from present area. Using the rVLR-B, the cost of maintaining location of mobile users was abridged. The second technique for reducing the costs during the location tracking and location update is proposed. Taking the regular movement pattern of the users it produces the block and the user registers with the HLR only after crossing the block instead of crossing the single cell. The block register (BR) is introduced between the block and the HLR in two level systems to preserve the blocks, thus creates three level architecture. In this architecture some signaling cost values between the MSC-BR, BRHLR and BR-BR are maintained to get the better enactment. By the rVLR-B and BR the performance of speed of call delivery improved and location updation will be diminished. Keywords: Home Location Register, Visitor Location Register, Mobile Switching Center, Base Station, Block Register, Mobile Station, r-VLR- Representative VLR
The switching system allows calls to be set up between the mobile station (MS) and other networks. It involves switching and routing calls as well as checking various registers for location, subscription, and equipment information. The key nodes are the MSC/VLR, GMSC, HLR, AUC, EIR, and SMS-C. The MSC/VLR handles call setup, authentication, and maintaining connections to moving subscribers. The GMSC routes incoming calls to the correct MSC/VLR. The HLR and VLR contain subscription and location information for routing calls and updating location.
The document summarizes the architecture of the GSM network. It is divided into four main parts: the Mobile Station, the Base Station Subsystem, the Network and Switching Subsystem, and the Operation and Support Subsystem. The Mobile Station consists of the SIM card and mobile equipment. The Base Station Subsystem provides the interface between the mobile station and the network subsystem and manages radio resources. The Network and Switching Subsystem manages communications and includes databases for subscriber information. The Operation and Support Subsystem controls and monitors the entire GSM system.
Performance evaluation of the mobility management towards 4 g wireless netwoIAEME Publication
The document discusses performance evaluation of mobility management in 4G wireless networks. It specifically focuses on handoff management and location management. For handoff management, it proposes using relative received signal strength as a performance criterion. It presents the procedure of this proposed handoff scheme. For location management, it discusses location update and paging operations. It then proposes a location update scheme that predicts future location of a mobile host based on history of its movement pattern.
HUAWEI MASS & ROAMING TROUBLSHOUTING.pptxyoussef827458
The document discusses key components and configuration of Huawei mobile switching centers (MSCs) in Maroc Telecom's roaming network. It begins with definitions of MSCs and mobile switching systems (MSSs), then provides details on Maroc Telecom's 8 Huawei MSCs and their locations. The document outlines MSC commands, a basic call flow, and procedures for configuring Huawei MSCs in the roaming center network, including called and incoming number analysis rules.
This document analyzes the effect of different velocities on handover delay in WiMAX systems. It studies location management area based multimedia and multicast/broadcast handover. The study compares the number of cells and size of location areas using a simulation to see how these parameters are affected by different mobile WiMAX velocities. It presents an analytical model and discusses numerical results analyzing handover delay with modifications to reduce delay by focusing on different mobile WiMAX mobility velocities and comparing to the convergence area size of location management areas.
This document analyzes the effect of different velocities on handover delay in WiMAX systems. It studies location management area based multimedia and multicast/broadcast handover and compares how modifying mobile WiMAX velocity levels and the size of location areas affect handover delay. The study finds that as mobile velocity increases, the rate of cell and location area boundary crossings increases, leading to more handovers and higher handover delay. Parameters like location area size, user distribution, and session popularity also impact average service disruption time during handovers.
This document reviews a mobility management scheme for mobile communication systems. It was found that mobile-to-mobile call setup times performed better than fixed network-to-mobile or mobile-to-fixed call setup times. Additionally, increasing the number of location areas within a switch did not affect inter-MSC handovers or location updates since the switch coverage area size remained the same, but did increase intra-MSC location updates and handovers. Finally, user mobility directly impacts signaling traffic for handovers, location management, radio resource allocation, and routing.
Mobility Management Scheme for Mobile Communication Systems. A Reviewiosrjce
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1. Mobility Management in Wireless Communication – Chapter 12
By
Donavon M. Norwood
CS286
Dr. Moh
2. Introduction - 12.1
Mobility is very important in mobile communication, and can be classified as radio mobility and
network mobility. Radio mobility is mainly concerned with the handoff process, whereas
network mobility deals with mobile location management (i.e., location and updating). The public
land mobile network (PLMN) is a cellular network that provides wireless services to mobile
subscribers to other networks and network services, which include other PLMN's. The PLMN is
divided into regions called LA's, (Location Areas), which are made up of one or more cell areas.
A mobile station (MS) registers with the visitor location register (VLR) each time it enters a
new LA, and is free to move inside the LA without registration. Each cell has a unique
identification number called a cell global identification (CGI), which contains location area
identification (LAI) and the cell identification (CI). The LAI consists of mobile country code
(MCC), mobile network code (MNC), and location area code (LAC). Mobility management in
wireless networks is the primary set of functions important to a network in order to enable
subscriber mobility, which includes enabling the network to keep track of a subscribers status
and location in order to deliver calls to the subscriber. The key component to mobility
management is the subscribers service profile, which is a database record in the network that
contains information about each subscriber. The data in the record is dynamic such as current
location and status of subscriber and permanent data such as service profile, international mobile
subscriber identity (IMSI), etc., of the subscriber.
2
5. Mobility Management Functions - 12.2
Mobility management generally deals with automatic roaming, authentication, and
intersystem handoff. Automatic roaming includes a set of network functions that allow
the subscriber obtain service outside the home service provider area. These functions
are automatic and do not require special subscriber actions. Automatic roaming functions
are divided into:
I. Mobile station (MS) service qualification
II. MS location management
III. MS state management
IV. Home location register (HLR) and VLR fault recovery
The authentication process requires that the end users of the system are authenticated.
Handoff is one of the essential features that guarantee the subscriber mobility in a mobile
network where the subscriber can move around. The handoff function allows the moving
subscriber to maintain a connection. In simple terms the handoff functions works when a
subscriber moves into a new cell a new connection has to be established and the cell in
which the subscriber left from has to be disconnected.
5
6. Mobile Location Management - 12.3
Location management schemes are based on subscribers mobility and
incoming call rate characteristics. The location update (LU) is used by the
network to keep track of the mobile subscribers location to direct a incoming
call. A paging process transmits paging messages to all the cells were
mobile terminals are located. If a LU cost is high, the the paging cost is low
and paging is performed over a small area. When LU cost is low, then
paging cost is high and paging is performed over a wider area. Location
management uses either the periodic LU or LU-on-LA-crossing. The VLR
stores the LAI, and the HLR keeps the VLR identifier. Using the periodic LU
method, the MS periodically sends its identity to the network, but the
drawback to using this method is resource consumption, and an example
would be if a MS does not move in a new LA for several hours. In the LU-on-
LA-crossing method, every base station will periodically broadcast the identity
of the LA. The MS is required to listen to network broadcast information and
store the current LA identity if the one stored in the MS is different. The LU
procedure is is automatically done by the MS. The advantage of this method
is that LU's are only generated when the MS moves.
6
7. Mobility Model - 12.3.1
A mobility model describes the occurrence of procedures such as LU and handoff, and
several models have been proposed.
Fluid model: This model assumes that the traffic flow to be like the flow of fluid. The
model suggests that the amount of traffic flowing out of the area is proportional to the
population density of the area, average velocity of movement and the length of the area
boundary. For an area the average number of crossings per unit time is given as:
L
=
=number of crossings per unit of time , =average population density ,
=average movement velocity of the area , L= perimeter of the area
7
8. Mobility Model – 12.3.1 (Continued)
Markovian model: Known as the random walk model, this model describes individual
movement. Also in this model a mobile subscriber remains within a region or moves to an
adjacent region according to a transition probability distribution. One of the limitations of
this model is that there is no concept of trips.
Gravity model: Different types of this model have been employed in transportation
research to model human movement behavior. This model also has been applied to
regions of varying sizes, from city models to national and international models. This
model is difficult because many parameters are required in the calculations, therefore it is
difficult to model geography with many regions.
8
9. Mobile Registration - 12.4
The detection of a subscriber in a new serving system is an example of a registration
event, which is a subset of automatic roaming functions, which consists of MS service
qualification and MS location management. These two functions allow the subscriber
to register with the network, that is to indicate to the network location register
functional entities of the location and status of the MS. The registration functions need
to be performed before the network can provide service to the subscriber, with the
exception of emergency services like 911. Registration may be initiated by the MS or
the network, or may be implied during the MS access. Upon receiving the registration
request from a MS, the base station (BS) constructs the Registration Update
Request message and sends it to the MSC (Mobile Switching Center), which contains
the MS's identification and location information and may contain authorization
parameters. The MSC may respond with a request for authorization (optional) and
finally with a Registration Update Response message. The MSC sends the
Registration Update Response to the BS when the registration procedure has been
successfully completed, and this message also indicates whether the MS's registration
has been accepted or rejected. The three possible results in the registration request
are: successful registration, unsuccessful registration, and cancellation of
registration.
9
10. Mobile Registration – 12.4 (Continued)
Registration Types
Distance-based registration: when the distance between the current cell and the cell
where the mobile last registered exceeds a threshold.
Geographic-based registration: whenever a mobile station enters a new area of the
same system.
Parameter change registration: when specific operating parameters in the mobile are
changed.
Periodic registration: when the system sets parameters on the forward control
channel to indicate that all or some of the mobile stations must register.
Power-down registration: when the mobile is switched off. This allows the network to
deregister a mobile immediately upon its power-down.
Power-up registration: when power is applied to the mobile, and used to notify the
network that the mobile is now active and ready to place or receive calls.
Timer-based registration: when a timer expires in the mobile.
10
11. Figure 12.3 Call flows for MS registration of all mobiles listening to a
control channel (ANSI-41 Standard)
11
12. GSM Token-Based Registration - 12.4.1
When an MS registers with the new network, it sends its TMSI and LAI. The LAI informs the system
where to find the old VLR. The network then queries the old VLR for data and uses the data to
authenticate the MS. The new VLR then communicates with the HLR to update the location of the MS.
The HLR sends a registration cancellation message to the old VLR. The operation of the token-based
system is slightly different from the ANSI-41 system in that the segmentation of call processing between
the BS, MSC and VLR is defined differently. Here are the steps for Token-Based registration:
1. MS sends registration message to the visiting system with its old TMSI and old LAI.
2. Visiting system queries the old VLR for data.
3. Old VLR returns security-related information.
4. Visiting system issues a challenge to the MS.
5. MS responds to challenge.
6. Visiting system assigns new TMSI.
7. Visiting system sends a message to the HLR with location update information
8. HLR updates its its location database with new location of the MS.
9. HLR acknowledges messages and may send other security related information.
10. HLR sends a registration cancellation to old system.
11. Visiting system sends an encrypted message to the MS with new TMSI.
12. MS acknowledges the message.
12
14. IMSI Attach and ISMSI Detach
(Registration and Deregistration) in GSM - 12.4.2
In GSM a mobile power-up implies a IMSI attach which causes a mobile
registration. See figure 12.5.
14
16. IMSI Attach and ISMSI Detach
(Registration and Deregistration) in GSM – 12.4.2
(Continued)
In GSM a mobile power-down implies a IMSI detach
which causes a mobile deregistration. See figure 12.6.
16
18. Paging in GSM - 12.4.3
In this scenario we assume that the mobile is already
registered with the system and has acquired a TMSI. It is
also assumed that the mobile is located in its home network.
A land subscriber dials the number of the mobile subscriber.
See Figure 12.7.
18
20. Handoff – 12.5
As a mobile moves from one cell to another, an active call must
undergo a switch from one channel to another. This process is
called handover and handoff. In TDMA systems handoff usually
involves both a change of channel carrier frequency and time slot.
It also may require a reconfiguration of the wireline facilities by
dropping the connection to the serving (old) BSS and switching to
a connection to the new (target) BSS as shown in figure 12.8. In
this example the mobile tunes from carrier frequency 6 on time
slot 3 served by the old BSS to carrier frequency 9 on time slot 7
by the new BSS (Interfrequency handoff).
20
22. Handoff – 12.5 (Continued)
Handoff is initiated because of a variety of reasons. Signal strength deterioration is the most
common reason for handoff at the edge of a cell. Other reasons could be due to load
balancing where the handoff is network initiated to relieve traffic congestion by shifting calls in
a highly congested cell to a lightly loaded cell. The handoff could be synchronous or
asynchronous. Handoffs are initiated by the BSC based upon radio subsystem criteria such
as RF level (RXLEV), signal quality (RXQUAL) or distance, or they are a result of network
traffic loading. Appropriate decisions are made by a handoff algorithm. The measurements
performed by the MS and the BTS which are collated by the BSC include:
• MS – RXLEV and RXQUAL (for serving downlink and adjacent BS's)
• BTS – RXQUAL and RXLEV (uplink for serving BS)
There are two types of handoff: internal and external. If the serving and target base station are
located in the same BSS, the BSC for the BSS performs the handoff process without the help
of a MSC. This type of handoff is known as a intra-BSS handoff. However if the serving and
target base stations are not in the same BSS, and external handoff is performed in which a
MSC coordinates the handoff performs the switching task between the serving and target base
stations. External handoffs can be either in the same MSC (intra-MSC) or between different
MSC's (inter-MSC).
22
23. Handoff Techniques - 12.5.1
Handoff techniques can be classified as mobile-controlled handoff (MCHO), network
-controlled handoff (NCHO), and mobile-assisted handoff (MAHO). In MCHO the
mobile continuously monitors the signal strength and quality from the serving base station
and several handoff candidate base stations. When the handoff criteria are met, the
mobile checks the candidate base station for an available traffic channel and launches a
handoff request. NCHO is employed by a low-tier CT-2+ and a high-tier AMPS system.
In this case the base station monitors the strength and signal quality from the mobile.
When these fall below a certain threshold, the network arranges for a handoff to another
station. The network asks all surrounding base stations to monitor the signal strength
from the mobile and report the measurements back to the network. The network
selects a new base station for handoff and informs both the mobile and new base station.
MAHO strategy has been employed by high-tier 2G (GSM, IS-95 CDMA, IS-136 TDMA)
and 3G (WCDMA, cdma200) systems. In this approach the network provides the mobile
with a list of base station frequencies (those of nearby base stations). The network asks
the mobile to measure the signal strengths and signal quality from the surrounding base
stations and report the measurements back to the serving base stations so the network
can decide whether a handoff is required and to which base station.
23
24. Handoff Types - 12.5.2
Handoff can be categorized as hard handoff, soft handoff, and softer handoff. Hard
handoff can be further divided into intrafrequency and interfrequency hard handoffs. A
hard handoff occurs when the old connection terminated before making a new
connection. In the case of a interfrequency hard handoff, the carrier frequency is different
from the old carrier frequency which the MS was connected to. If the new frequency of
the carrier is the same as the old frequency in which the MS was connected to, this is
called a intrafrequency handoff. In 2G TDMA systems the majority of the handoffs are
intrafrequency handoffs. Interfrequency handoffs may occur between two different radio
access networks. In this case it can also be called a intersystem handoff. A intersystem
handoff is always a type of interfrequency since different frequencies are used in different
systems. A soft handoff occurs when a new connection is made before the old
connections is released. In 3G systems the majority of handoffs are intrafrequency
handoffs. A 2-way soft handoff happens when two sectors with different BS's that do
not belong to the same BSC. A softer handoff occurs when a BS transmit through one
sector but receives responses from more than one sector. When a soft and softer
handoff occurs at the same time, this is called a soft-softer handoff.
24
25. Handoff Process and Algorithms - 12.5.3
A basic handoff process consists of three main phases which include measurements,
decision and execution phase.
• Measurement phase - the MS continuously measures the signal strength of of the
serving and neighboring cells, and reports the results to the network.
• Decision phase - consists of an assessment of the overall quality of service (QoS)
of the connection and comparing it with the requested QoS attributes and estimates
from neighboring cells. A handoff my occur depending on the outcome of the
comparisons.
• Execution phase - involves handoff signaling and radio resource allocation. Radio
signal strength (RSS) measurements from the serving cell and neighboring cells
are primarily used in most networks.
25
26. Handoff Process and Algorithms – 12.5.3
(Continued)
The following parameters are generally used in the handoff algorithm:
• Upper threshold: the level at which the signal strength of the connection is at the maximum
acceptable level with respect to the required QoS.
• Lower threshold: the minimum level of the signal strength to satisfy the required QoS, thus
the signal strength of the connection can not fall below this level.
• Handoff margin: a predefined parameter set in which the signal strength of neighboring cell
exceeds that of the serving cell by a certain amount or a certain time.
Some of the traditional handoff algorithms are as follows:
i. RSS type: the BS with the largest signal strength is selected
ii. RSS plus threshold type: a handoff is performed if the RSS of the new BS exceeds that of
the serving BS and the signal strength of the serving BS is below the lower threshold value.
iii. RSS plus handoff margin type: a handoff is performed if the RSS of the new BS is more
than that of the serving BS by a handoff margin/
* RSS (Radio Signal Strength)
26
28. Handoff Call Flows (Intra-MSC Handoff) - 12.5.4
In Intra-MSC Handoff the MS constantly monitors the signal
quality of the BSS link, or optionally the BSS will forward its
measurements to the MS. When the signal quality os poor, the MS
will attempt to maintain the desired signal quality of the radio link
By requesting a handoff. The following steps on the left occur in a
Intra-MSC Handoff.
28
30. Handoff Call Flows (Inter-MSC Handoff) - 12.5.4
In this scenario we assume that a call has already been
established. The serving BSS is connected to the
servingMSC, and the target BSS to the target MSC (see
figure 12.11).
30