This document provides an overview of wireless LAN and Bluetooth technologies. It describes IEEE 802.11 standards for wireless LAN including the basic service set, extended service set, infrastructure and ad-hoc modes. It covers the physical layers, MAC protocols and services of 802.11. It also summarizes ATM and its extension to wireless networks, issues in the transition, proposed W-ATM architectures, advantages and disadvantages. Finally it defines Bluetooth technology, the protocol stack and unlicensed frequency band used.
The document discusses wireless local area networks (WLANs) and personal area networks (PANs). It describes the characteristics and fundamentals of WLANs, including their advantages like flexibility and lower costs, and disadvantages such as lower bandwidth and security issues. It provides details on common wireless standards like IEEE 802.11, Bluetooth, and HomeRF. It also compares infrastructure-based and ad-hoc network topologies and summarizes key aspects of the IEEE 802.11 standard including services, physical layers, and frame formats.
Pmit lecture 03_wlan_wireless_network_2016Chyon Ju
The document discusses requirements and specifications for wireless local area networks (WLANs). It notes that the IEEE 802 committee develops standards for wired and wireless networking, including 802.11 for WLANs. The document then describes several 802.11 specifications such as 802.11, 802.11a, 802.11b, and 802.11g that define transmission speeds and frequencies for WLANs. It also discusses modulation techniques like BPSK and QPSK used in wireless communications.
IEEE 802.11 defines wireless local area networks. It uses CSMA/CA for media access and includes encryption. Wireless networks can operate in ad-hoc mode with no base station or in infrastructure mode with an access point. Infrastructure networks can connect multiple basic service sets to extend the network. Stations can have no, basic, or extended mobility between networks. Physical layer standards include FHSS, DSSS, OFDM, and their variants.
The document discusses several aspects of wireless local area networks (WLANs) including:
1. IEEE 802.11b is an enhancement of the original 802.11 standard that achieved data rates up to 11 Mbps using modifications to the physical layer.
2. IEEE 802.11a operates in the 5GHz band and supports data rates up to 54 Mbps using orthogonal frequency-division multiplexing (OFDM).
3. Many future developments are planned including enhancements to security, quality of service, and higher data rates above 100 Mbps.
These ppt are the part 2 of mobile computing concepts. These ppt defines the following things
Wireless Networking
Wireless LAN Overview: IEEE 802.11
Wireless applications
Data Broadcasting
Bluetooth
TCP over wireless
Mobile IP
WAP: Architecture, protocol stack, application
environment, applications.
The document discusses wireless networks and IEEE 802.11 standards. It describes the components of wired LANs like repeaters, hubs, bridges, and switches. It then covers wireless networks including wireless LAN standards like 802.11b, 802.11a, and 802.11g. It also discusses wireless network topologies, services, and the medium access control of 802.11 which uses CSMA/CA for distributed coordination function and an alternative point coordination function for centralized access control.
The document discusses wireless local area networks (WLANs) and personal area networks (PANs). It describes the characteristics and fundamentals of WLANs, including their advantages like flexibility and lower costs, and disadvantages such as lower bandwidth and security issues. It provides details on common wireless standards like IEEE 802.11, Bluetooth, and HomeRF. It also compares infrastructure-based and ad-hoc network topologies and summarizes key aspects of the IEEE 802.11 standard including services, physical layers, and frame formats.
Pmit lecture 03_wlan_wireless_network_2016Chyon Ju
The document discusses requirements and specifications for wireless local area networks (WLANs). It notes that the IEEE 802 committee develops standards for wired and wireless networking, including 802.11 for WLANs. The document then describes several 802.11 specifications such as 802.11, 802.11a, 802.11b, and 802.11g that define transmission speeds and frequencies for WLANs. It also discusses modulation techniques like BPSK and QPSK used in wireless communications.
IEEE 802.11 defines wireless local area networks. It uses CSMA/CA for media access and includes encryption. Wireless networks can operate in ad-hoc mode with no base station or in infrastructure mode with an access point. Infrastructure networks can connect multiple basic service sets to extend the network. Stations can have no, basic, or extended mobility between networks. Physical layer standards include FHSS, DSSS, OFDM, and their variants.
The document discusses several aspects of wireless local area networks (WLANs) including:
1. IEEE 802.11b is an enhancement of the original 802.11 standard that achieved data rates up to 11 Mbps using modifications to the physical layer.
2. IEEE 802.11a operates in the 5GHz band and supports data rates up to 54 Mbps using orthogonal frequency-division multiplexing (OFDM).
3. Many future developments are planned including enhancements to security, quality of service, and higher data rates above 100 Mbps.
These ppt are the part 2 of mobile computing concepts. These ppt defines the following things
Wireless Networking
Wireless LAN Overview: IEEE 802.11
Wireless applications
Data Broadcasting
Bluetooth
TCP over wireless
Mobile IP
WAP: Architecture, protocol stack, application
environment, applications.
The document discusses wireless networks and IEEE 802.11 standards. It describes the components of wired LANs like repeaters, hubs, bridges, and switches. It then covers wireless networks including wireless LAN standards like 802.11b, 802.11a, and 802.11g. It also discusses wireless network topologies, services, and the medium access control of 802.11 which uses CSMA/CA for distributed coordination function and an alternative point coordination function for centralized access control.
The document discusses the components and characteristics of wireless local area networks (WLANs). It describes the basic components of a WLAN including access points, WLAN adapters, and software. It discusses characteristics such as typical ranges of access points, the number of users supported, and how multiple access points can be connected. It also covers topics such as roaming between access points, infrastructure versus ad-hoc network architectures, and standards like IEEE 802.11.
This document discusses data networking and client-server communication. It covers distributed systems, network protocols, the OSI reference model, networking terminology like LANs and topologies, transmission networks, Ethernet, connecting to the internet, transport protocols like TCP and UDP, and IP addressing. Key concepts include layered network protocols, circuit-switched vs packet-switched networks, and connection-oriented vs connectionless protocols.
The document discusses wireless local area networks (WLANs) and the IEEE 802.11 standard. It provides an overview of wired and wireless LANs, the development and specifications of IEEE 802.11, and differences between wireless and wired networks that 802.11 addresses like power management, security, and bandwidth. It also covers wireless LAN topologies, media access control, security issues, and physical layer standards defined in original 802.11 like frequency hopping spread spectrum and direct sequence spread spectrum.
The document provides an overview of ZigBee/IEEE 802.15.4 wireless technology. It discusses the need for low-power, low-cost wireless connectivity for applications like home automation, medical devices, and industrial sensors. It describes the ZigBee Alliance's role in developing networking and application standards on top of the IEEE 802.15.4 physical radio specification. Key features of ZigBee networks include low power consumption, large network capacity, low data rates, and flexibility for many applications.
The document summarizes several IEEE 802 standards for local area networks (LANs):
- IEEE 802 defines the LLC and MAC sublayers for LANs. IEEE 802.3 specifies Ethernet LANs using CSMA/CD. IEEE 802.5 specifies Token Ring LANs.
- IEEE 802.3 Ethernet uses CSMA/CD where computers listen for traffic before transmitting and can detect collisions.
- IEEE 802.5 Token Ring LANs use a token passing protocol where a token circulates and only the computer holding the token can transmit.
IEEE 802.11 is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, 5, and 60 GHz frequency bands. It provides connectivity through wireless stations organized into basic service sets (BSSs) that together form an extended service set (ESS). Key components include the MAC sublayer, physical layers using technologies like direct sequence spread spectrum (DSSS), and services that enable station mobility and quality of service (QoS).
802.11 wireless LAN provides wireless network connectivity using access points that act as bridges between the wireless and wired networks. Access points are connected to the wired network and have antennas to provide wireless connectivity. The range of wireless connectivity depends on structural barriers and the access point antenna's RF gain. To cover larger areas, multiple access points with 20-30% overlap may be installed.
802.11 wireless LANs provide network connectivity over wireless media using access points that act as bridges between wireless and wired networks. Access points are connected to the wired network and have antennas to provide wireless connectivity. The range of wireless connectivity depends on structural hindrances and the access point's antenna gain. Multiple access points with overlapping ranges can service larger areas. Common 802.11 standards include 802.11b, 802.11a, and 802.11g.
This document provides information on wireless LAN (WLAN) technology and components. It discusses how an 802.11 wireless network connects desktop and laptop devices to a wired LAN using access points. Access points act as bridges between the wireless and wired networks. The document also covers the MACA protocol for wireless transmission and the different 802.11 wireless standards. It defines the functions of repeaters, hubs, bridges, and switches as components used in both wired and wireless networking.
The document discusses 802.11 wireless LAN technologies. It describes how an access point acts as a bridge between the wired and wireless networks, and how wireless connectivity is provided through antennae on the access point. It also discusses the different 802.11 standards including 802.11b, 802.11a, and 802.11g, and how they operate on different frequency bands and support different data rates. Finally, it summarizes the differences between repeaters, hubs, bridges, and switches, and how they operate at different layers of the OSI model.
Wireless networking technology uses wireless stations like computers or devices with radios to transmit and receive data without wires. There are two main types of wireless networks: infrastructure networks with an access point that devices connect to and ad-hoc peer-to-peer networks without an access point where devices connect directly. Wireless networks use radio frequencies and transmission methods like frequency hopping spread spectrum or direct sequence spread spectrum to transmit data over the air. Newer standards are developing technologies like MIMO that use multiple antennas to improve wireless network performance and speeds.
This document provides an overview of wireless local area networks (WLANs) and various IEEE 802.11 standards. It describes the characteristics and design goals of WLANs. It also compares infrastructure vs. ad-hoc network architectures and examines the physical layer, MAC layer, and management functions of 802.11. Specific standards like 802.11a, 802.11b, and future developments are outlined. The document provides details on aspects like channel selection, data rates, transmission ranges, and security considerations for different 802.11 technologies.
This document discusses various configurations and technologies for wireless local area networks (WLANs). It describes single-cell and multi-cell configurations, and applications for cross-building interconnects and ad hoc networking. Key requirements for WLANs are also outlined. The main technologies discussed are infrared (IR) LANs, spread spectrum LANs using the IEEE 802.11 standard, and narrowband microwave LANs. Specific topics covered include infrastructure and configurations, services, medium access control, and priority schemes using different interframe spaces.
Ethernet and Fast Ethernet standards define the physical implementation of local area networks using twisted pair cable and fiber optics. Ethernet uses CSMA/CD access method over coaxial cable or twisted pair up to 100 meters, while Fast Ethernet operates at 100 Mbps over twisted pair or fiber. Repeaters can extend the length of an Ethernet segment by regenerating the signal past the maximum segment distance.
This document discusses quality of service (QoS) provisioning in wireless multimedia networks. It describes QoS challenges in wireless networks due to limited bandwidth, unreliable links, and varying channel conditions. It also discusses the characteristics of multimedia services and traffic modeling challenges. The document outlines IEEE 802.11 MAC layer enhancements including the distributed coordination function, point coordination function, and IEEE 802.11e standard for supporting QoS through enhanced distributed channel access and hybrid coordination function. It emphasizes the need for end-to-end QoS, adaptive frameworks, and call admission control for wireless multimedia networks.
The document discusses several aspects of wireless personal area networks (WPANs), focusing on Bluetooth and ZigBee technologies. It defines WPANs as conveying information over short distances with little infrastructure. Bluetooth is described as the most widely used WPAN technology, operating using piconets of up to 8 devices within 10 meters of each other. Key aspects of Bluetooth like frequency hopping, link types, and data rates are summarized. The Bluetooth architecture is broken down into its radio, baseband, link manager, and L2CAP layers.
The document provides information on the evolution of wireless networks from 1G to 3G. It discusses the key components and architecture of cellular systems including base stations, mobile switching centers and their connection to the public switched telephone network. It also compares the differences between wireless and wired networks, and describes some of the limitations of early wireless networking. Finally, it covers topics like traffic routing, circuit switching, packet switching and the X.25 protocol.
Ethernet protocols refer to the family of local-area network (LAN) standards covered by IEEE 802.3. Ethernet networks can operate in either half-duplex or full-duplex mode and support data rates of 10 Mbps, 100 Mbps, 1000 Mbps, and 10 Gbps. The basic elements of an Ethernet system are the physical medium, medium access control rules, and Ethernet frames. Ethernet frames contain fields for source and destination addresses, length/type, data, and error checking.
The document discusses free computer science eBooks and technology news that are being provided. It includes links to blogs sharing this free content and encourages clicking on advertisements to support their work. It then discusses the topics of wireless technologies and Wi-Fi networks in particular, covering introductions, architectures, elements, how they work, topologies and configurations.
The document discusses key aspects of IEEE 802.11 wireless networks including:
1) IEEE 802.11 standards such as 802.11b, 802.11g, and 802.11n which specify protocols for wireless LANs and have varying maximum bandwidths and modulation techniques.
2) Wireless network components like access points, bridges, and clients that connect devices to the network.
3) Network configuration settings including channel, fragmentation threshold, network type (infrastructure vs. ad-hoc), SSID, and authentication that determine how the network operates.
The document discusses the components and characteristics of wireless local area networks (WLANs). It describes the basic components of a WLAN including access points, WLAN adapters, and software. It discusses characteristics such as typical ranges of access points, the number of users supported, and how multiple access points can be connected. It also covers topics such as roaming between access points, infrastructure versus ad-hoc network architectures, and standards like IEEE 802.11.
This document discusses data networking and client-server communication. It covers distributed systems, network protocols, the OSI reference model, networking terminology like LANs and topologies, transmission networks, Ethernet, connecting to the internet, transport protocols like TCP and UDP, and IP addressing. Key concepts include layered network protocols, circuit-switched vs packet-switched networks, and connection-oriented vs connectionless protocols.
The document discusses wireless local area networks (WLANs) and the IEEE 802.11 standard. It provides an overview of wired and wireless LANs, the development and specifications of IEEE 802.11, and differences between wireless and wired networks that 802.11 addresses like power management, security, and bandwidth. It also covers wireless LAN topologies, media access control, security issues, and physical layer standards defined in original 802.11 like frequency hopping spread spectrum and direct sequence spread spectrum.
The document provides an overview of ZigBee/IEEE 802.15.4 wireless technology. It discusses the need for low-power, low-cost wireless connectivity for applications like home automation, medical devices, and industrial sensors. It describes the ZigBee Alliance's role in developing networking and application standards on top of the IEEE 802.15.4 physical radio specification. Key features of ZigBee networks include low power consumption, large network capacity, low data rates, and flexibility for many applications.
The document summarizes several IEEE 802 standards for local area networks (LANs):
- IEEE 802 defines the LLC and MAC sublayers for LANs. IEEE 802.3 specifies Ethernet LANs using CSMA/CD. IEEE 802.5 specifies Token Ring LANs.
- IEEE 802.3 Ethernet uses CSMA/CD where computers listen for traffic before transmitting and can detect collisions.
- IEEE 802.5 Token Ring LANs use a token passing protocol where a token circulates and only the computer holding the token can transmit.
IEEE 802.11 is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, 5, and 60 GHz frequency bands. It provides connectivity through wireless stations organized into basic service sets (BSSs) that together form an extended service set (ESS). Key components include the MAC sublayer, physical layers using technologies like direct sequence spread spectrum (DSSS), and services that enable station mobility and quality of service (QoS).
802.11 wireless LAN provides wireless network connectivity using access points that act as bridges between the wireless and wired networks. Access points are connected to the wired network and have antennas to provide wireless connectivity. The range of wireless connectivity depends on structural barriers and the access point antenna's RF gain. To cover larger areas, multiple access points with 20-30% overlap may be installed.
802.11 wireless LANs provide network connectivity over wireless media using access points that act as bridges between wireless and wired networks. Access points are connected to the wired network and have antennas to provide wireless connectivity. The range of wireless connectivity depends on structural hindrances and the access point's antenna gain. Multiple access points with overlapping ranges can service larger areas. Common 802.11 standards include 802.11b, 802.11a, and 802.11g.
This document provides information on wireless LAN (WLAN) technology and components. It discusses how an 802.11 wireless network connects desktop and laptop devices to a wired LAN using access points. Access points act as bridges between the wireless and wired networks. The document also covers the MACA protocol for wireless transmission and the different 802.11 wireless standards. It defines the functions of repeaters, hubs, bridges, and switches as components used in both wired and wireless networking.
The document discusses 802.11 wireless LAN technologies. It describes how an access point acts as a bridge between the wired and wireless networks, and how wireless connectivity is provided through antennae on the access point. It also discusses the different 802.11 standards including 802.11b, 802.11a, and 802.11g, and how they operate on different frequency bands and support different data rates. Finally, it summarizes the differences between repeaters, hubs, bridges, and switches, and how they operate at different layers of the OSI model.
Wireless networking technology uses wireless stations like computers or devices with radios to transmit and receive data without wires. There are two main types of wireless networks: infrastructure networks with an access point that devices connect to and ad-hoc peer-to-peer networks without an access point where devices connect directly. Wireless networks use radio frequencies and transmission methods like frequency hopping spread spectrum or direct sequence spread spectrum to transmit data over the air. Newer standards are developing technologies like MIMO that use multiple antennas to improve wireless network performance and speeds.
This document provides an overview of wireless local area networks (WLANs) and various IEEE 802.11 standards. It describes the characteristics and design goals of WLANs. It also compares infrastructure vs. ad-hoc network architectures and examines the physical layer, MAC layer, and management functions of 802.11. Specific standards like 802.11a, 802.11b, and future developments are outlined. The document provides details on aspects like channel selection, data rates, transmission ranges, and security considerations for different 802.11 technologies.
This document discusses various configurations and technologies for wireless local area networks (WLANs). It describes single-cell and multi-cell configurations, and applications for cross-building interconnects and ad hoc networking. Key requirements for WLANs are also outlined. The main technologies discussed are infrared (IR) LANs, spread spectrum LANs using the IEEE 802.11 standard, and narrowband microwave LANs. Specific topics covered include infrastructure and configurations, services, medium access control, and priority schemes using different interframe spaces.
Ethernet and Fast Ethernet standards define the physical implementation of local area networks using twisted pair cable and fiber optics. Ethernet uses CSMA/CD access method over coaxial cable or twisted pair up to 100 meters, while Fast Ethernet operates at 100 Mbps over twisted pair or fiber. Repeaters can extend the length of an Ethernet segment by regenerating the signal past the maximum segment distance.
This document discusses quality of service (QoS) provisioning in wireless multimedia networks. It describes QoS challenges in wireless networks due to limited bandwidth, unreliable links, and varying channel conditions. It also discusses the characteristics of multimedia services and traffic modeling challenges. The document outlines IEEE 802.11 MAC layer enhancements including the distributed coordination function, point coordination function, and IEEE 802.11e standard for supporting QoS through enhanced distributed channel access and hybrid coordination function. It emphasizes the need for end-to-end QoS, adaptive frameworks, and call admission control for wireless multimedia networks.
The document discusses several aspects of wireless personal area networks (WPANs), focusing on Bluetooth and ZigBee technologies. It defines WPANs as conveying information over short distances with little infrastructure. Bluetooth is described as the most widely used WPAN technology, operating using piconets of up to 8 devices within 10 meters of each other. Key aspects of Bluetooth like frequency hopping, link types, and data rates are summarized. The Bluetooth architecture is broken down into its radio, baseband, link manager, and L2CAP layers.
The document provides information on the evolution of wireless networks from 1G to 3G. It discusses the key components and architecture of cellular systems including base stations, mobile switching centers and their connection to the public switched telephone network. It also compares the differences between wireless and wired networks, and describes some of the limitations of early wireless networking. Finally, it covers topics like traffic routing, circuit switching, packet switching and the X.25 protocol.
Ethernet protocols refer to the family of local-area network (LAN) standards covered by IEEE 802.3. Ethernet networks can operate in either half-duplex or full-duplex mode and support data rates of 10 Mbps, 100 Mbps, 1000 Mbps, and 10 Gbps. The basic elements of an Ethernet system are the physical medium, medium access control rules, and Ethernet frames. Ethernet frames contain fields for source and destination addresses, length/type, data, and error checking.
The document discusses free computer science eBooks and technology news that are being provided. It includes links to blogs sharing this free content and encourages clicking on advertisements to support their work. It then discusses the topics of wireless technologies and Wi-Fi networks in particular, covering introductions, architectures, elements, how they work, topologies and configurations.
The document discusses key aspects of IEEE 802.11 wireless networks including:
1) IEEE 802.11 standards such as 802.11b, 802.11g, and 802.11n which specify protocols for wireless LANs and have varying maximum bandwidths and modulation techniques.
2) Wireless network components like access points, bridges, and clients that connect devices to the network.
3) Network configuration settings including channel, fragmentation threshold, network type (infrastructure vs. ad-hoc), SSID, and authentication that determine how the network operates.
In May 2024, globally renowned natural diamond crafting company Shree Ramkrishna Exports Pvt. Ltd. (SRK) became the first company in the world to achieve GNFZ’s final net zero certification for existing buildings, for its two two flagship crafting facilities SRK House and SRK Empire. Initially targeting 2030 to reach net zero, SRK joined forces with the Global Network for Zero (GNFZ) to accelerate its target to 2024 — a trailblazing achievement toward emissions elimination.
Response & Safe AI at Summer School of AI at IIITHIIIT Hyderabad
Talk covering Guardrails , Jailbreak, What is an alignment problem? RLHF, EU AI Act, Machine & Graph unlearning, Bias, Inconsistency, Probing, Interpretability, Bias
How to Manage Internal Notes in Odoo 17 POSCeline George
In this slide, we'll explore how to leverage internal notes within Odoo 17 POS to enhance communication and streamline operations. Internal notes provide a platform for staff to exchange crucial information regarding orders, customers, or specific tasks, all while remaining invisible to the customer. This fosters improved collaboration and ensures everyone on the team is on the same page.
A vernier caliper is a precision instrument used to measure dimensions with high accuracy. It can measure internal and external dimensions, as well as depths.
Here is a detailed description of its parts and how to use it.
Profiling of Cafe Business in Talavera, Nueva Ecija: A Basis for Development ...IJAEMSJORNAL
This study aimed to profile the coffee shops in Talavera, Nueva Ecija, to develop a standardized checklist for aspiring entrepreneurs. The researchers surveyed 10 coffee shop owners in the municipality of Talavera. Through surveys, the researchers delved into the Owner's Demographic, Business details, Financial Requirements, and other requirements needed to consider starting up a coffee shop. Furthermore, through accurate analysis, the data obtained from the coffee shop owners are arranged to derive key insights. By analyzing this data, the study identifies best practices associated with start-up coffee shops’ profitability in Talavera. These findings were translated into a standardized checklist outlining essential procedures including the lists of equipment needed, financial requirements, and the Traditional and Social Media Marketing techniques. This standardized checklist served as a valuable tool for aspiring and existing coffee shop owners in Talavera, streamlining operations, ensuring consistency, and contributing to business success.
20CDE09- INFORMATION DESIGN
UNIT I INCEPTION OF INFORMATION DESIGN
Introduction and Definition
History of Information Design
Need of Information Design
Types of Information Design
Identifying audience
Defining the audience and their needs
Inclusivity and Visual impairment
Case study.
5. IEEE 802.11
Wireless connection within 100m range
This standard defines:
1.Medium Access Control (MAC) sub layer
2. MAC management protocols and services
3.Three Physical layer for wireless connectivity – fixed,
portable and moving devices
8. IEEE 802.11 - BSS
MAC protocol and physical medium specification for
wireless LANs
Smallest building block is basic service set (BSS)
Number of stations
Same MAC protocol
Competing for access to same shared wireless medium
May be isolated or connect to backbone distribution
system (DS) through access point (AP)
AP functions as bridge
DS can be switch, wired network, or wireless network
9. BSS Configuration
Simplest: each station belongs to single BSS
Within range only of other stations within BSS
Can have two BSSs overlap
Station could participate in more than one BSS
Association between station and BSS dynamic
Stations may turn off, come within range, and go out of
range
10. Extended Service Set (ESS)
Two or more BSS interconnected by DS
Typically, DS is wired backbone but can be any network
Appears as single logical LAN to LLC
11. Access Point (AP)
Logic within station that provides access to DS
Provides DS services in addition to acting as station
To integrate IEEE 802.11 architecture with wired LAN,
portal used
Portal logic implemented in device that is part of
wired LAN and attached to DS
E.g. Bridge or router
12. Services
Service Provider Category
Association Distribution system MSDU delivery
Authentication Station LAN access and
security
Deauthentication Station LAN access and
security
Dissassociation Distribution system MSDU delivery
Distribution Distribution system MSDU delivery
Integration Distribution system MSDU delivery
MSDU delivery Station MSDU delivery
Privacy Station LAN access and
security
Reassocation Distribution system MSDU delivery
15. scenario of IEEE 802.11 wireless LAN connected to a
switched IEEE 802.3 Ethernet via a bridge
16. Distributed Coordination Function
DCF sublayer uses CSMA
If station has frame to transmit, it listens to medium
If medium idle, station may transmit
Otherwise must wait until current transmission complete
No collision detection
Not practical on wireless network
Dynamic range of signals very large
Transmitting station cannot distinguish incoming weak signals
from noise and effects of own transmission
DCF includes delays
Amounts to priority scheme
Interframe space
17. Point Coordination Function (PCF)
Alternative access method implemented on top of DCF
Polling by centralized polling master (point coordinator)
Uses PIFS when issuing polls
PIFS smaller than DIFS
Can seize medium and lock out all asynchronous traffic while it issues polls
and receives responses
E.g. wireless network configured so number of stations with time-
sensitive traffic controlled by point coordinator
Remaining traffic contends for access using CSMA
Point coordinator polls in round-robin to stations configured for
polling
When poll issued, polled station may respond using SIFS
If point coordinator receives response, it issues another poll using PIFS
If no response during expected turnaround time, coordinator issues
poll
18. 802.11 Physical Layer
Subdivided into two
1. PLCP – Physical layer Convergence protocol - provides Clear Channel
Assessment (CCA) and PHY service access point (SAP)
2. PMD-Physical Medium Dependent – Modulation and
encoding/decoding
19. Original 802.11 Physical Layer -
FHSS
Frequency-hopping spread spectrum
2.4 GHz ISM band at 1 Mbps and 2 Mbps
Uses multiple channels
Signal hopping from one channel to another based on a pseudonoise sequence
1-MHz channels are used
23 channels in Japan
70 in USA
Hopping scheme adjustable
E.g. Minimum hop rate forUSA is 2.5 hops per second
Minimum hop distance 6 MHz in North America and most of Europe and 5
MHz in Japan
Two-level Gaussian FSK modulation for 1-Mbps
Bits encoded as deviations from current carrier frequency
For 2 Mbps, four-level GFSK used
Four different deviations from center frequency define four 2-bit combinations
21. Original 802.11 Physical Layer -
DSSS
Three physical media
Direct-sequence spread spectrum
2.4 GHz ISM band at 1 Mbps and 2 Mbps
Up to seven channels, each 1 Mbps or 2 Mbps, can be
used
Depends on bandwidth allocated by various national
regulations
13 in most European countries
One in Japan
Each channel bandwidth 5 MHz
Encoding scheme DBPSK for 1-Mbps and DQPSK for 2-
Mbps
23. Original 802.11 Physical Layer –
Infrared
Omnidirectional
Range up to 20 m
1 Mbps used 16-PPM (pulse position modulation)
Each group of 4 data bits mapped into one of 16-PPM symbols
Each symbol a string of 16 bits
Each 16-bit string consists of fifteen 0s and one binary 1
For 2-Mbps, each group of 2 data bits is mapped into one of
four 4-bit sequences
Each sequence consists of three 0s and one binary 1
Intensity modulation
Presence of signal corresponds to 1
29. RTS - READY TO SEND
CTS - CLEAR TO SEND
NAV - Network Allocation Vector
31. 802.11a
5-GHz band
Uses orthogonal frequency division multiplexing (OFDM)
Not spread spectrum
Also called multicarrier modulation
Multiple carrier signals at different frequencies
Some bits on each channel
Similar to FDM but all subchannels dedicated to single source
Data rates 6, 9, 12, 18, 24, 36, 48, and 54 Mbps
Up to 52 subcarriers modulated using BPSK, QPSK, 16-QAM, or
64-QAM
Depending on rate
Subcarrier frequency spacing 0.3125 MHz
Convolutional code at rate of 1/2, 2/3, or 3/4 provides forward error
correction
32. 802.11b
Extension of 802.11 DS-SS scheme
5.5 and 11 Mbps
Chipping rate 11 MHz
Same as original DS-SS scheme
Same occupied bandwidth
Complementary code keying (CCK) modulation to achieve higher
data rate in same bandwidth at same chipping rate
CCK modulation complex
Overview on next slide
Input data treated in blocks of 8 bits at 1.375 MHz
8 bits/symbol 1.375 MHz = 11 Mbps
Six of these bits mapped into one of 64 code sequences
Output of mapping, plus two additional bits, forms input to QPSK
modulator
35. What is ATM?
Asynchronous Transfer Mode (ATM)
A networking technology developed by the telephone
companies to handle all types of data using fixed 53-
byte cells, or packets.
Creates virtual point-to-point circuit connections
between the source and the destination.
Data rates from 25 to 622 Mbps.
36. What is ATM?
• The small cell size
allows ATM to transmit
video, audio, and
computer data over the
same network, while
guaranteeing a preset
QoS level for each.
37. The Promise of W-ATM
Extension of LAN for mobile user
Simplified wiring and configuration
Provide high-speed data access for users without need
for a new wired infrastructure
Create unforeseen opportunities for future
applications
39. Transition Issues
Physical Layer
Infrared vs. Radio
Circuit-switched vs. Packet-switched
Channel Coding
Multiple Antennas
Operating Frequency
Licensed vs. Unlicensed Frequency
40. Transition Issues
Data Link Layer
Encapsulation
Header Compression
ARQ (Automatic Repeat Request) vs. FEC (Forward
Error Correction)
Quality-of-Service Issues
Split Functionality
An Example Protocol
42. Advantages of W-ATM
Benefits of ATM made mobile
Free to roam
Flexible bandwidth allocation
Efficient multiplexing of traffic
Availability of existent ATM switching
Flexibility of reusing same frequency
Soft handoff without any data loss
43. Disadvantages of W-ATM
Delay to multi-path interference
Hop-by-hop routing method not adequate
Virtual connection takes longer
Poor physical level characteristics
High noise interference
Finding a suitable wireless channel
45. What is Bluetooth?
Bluetooth is a high-speed, low-power microwave
wireless link technology, designed to connect phones,
laptops, PDAs and other portable equipment together
with little or no work by the user. Bluetooth
technology allows users to make ad hoc wireless
connections between devices like mobile phones,
desktop or notebook computers without any cable.
Devices carrying Bluetooth-enabled chips can easily
transfer data at a speed of about 1 Mbps in basic mode
within a 50m range or beyond through walls, clothing
and even luggage bags.
47. BLUETOOTH PROTOCOL
Bluetooth uses the unlicensed 2.4 GHz ISM (Industrial Scientific
and Medical) frequency band. There are 79 available Bluetooth
channels spaced 1 MHz apart from 2.402 GHz to 2.480 GHz. The
Bluetooth standard is managed and maintained by Bluetooth
Special Interest Group. IEEE has also adapted Bluetooth as the
802.15.1a standard. Bluetooth allows power levels starting from
1mW covering 10cm to 100mW covering up to 100 meters. These
power levels are suitable for short device zone to personal area
network within a home.
Bluetooth supports both unicast (point-to-point) and multicast
(point-to-multipoint) connections. Bluetooth protocol uses the
concept of master and slave. In a master slave protocol a device
cannot talk as and when they desire. They need to wait till the
time the master allows them to talk.
49. BLUETOOTH PROTOCOL STACK
Different applications may run over different protocol
stacks. Nevertheless, each one of these different
protocol stacks use a common Bluetooth data link and
physical layer. Not all applications make use of all the
protocols. Instead, applications run over one or more
vertical slices from this protocol stack. Typically,
additional vertical slices are for services supportive of
the main application, like TCS Binary (Telephony
Control Specification), or SDP (Service Discovery
Protocol).
50. Bluetooth protocol stack can be divided into four basic
layers according to their functions.
1. Baseband,
2. Link Manager Protocol (LMP),
3. Logical Link Control and Adaption Protocol
(L2CAP),
4. Service Discovery Protocol (SDP).
51. 1. Baseband
The Baseband and Link Control Layer enable the physical
RF link between Bluetooth units forming a piconet. This
layer uses inquiry and paging procedures to synchronize
the transmission with different Bluetooth devices. Using
SCO (Synchronous Connection Oriented) and ACL
(Asynchronous Connection Less) links, different packets
can be multiplexed over the same RF link. ACL packets are
used for data only, while the SCO packet can contain audio
only or a combination of audio and data. All audio and data
packets can be provided with different levels of CRC (Cyclic
Redundancy Code) or FEC (Forward Error Correction) for
error detection or correction.
52. 2. Link Manager Protocol (LMP)
When two Bluetooth devices come within each other’s
radio range, link managers of either device discover
each other. LMP then engages itself in peer- to-peer
message exchange. These messages perform various
security functions starting from authentication to
encryption. LMP layer performs generation and
exchange of encryption keys as well. This layer
performs the link setup and negotiation of baseband
packet size. LMP also controls the power modes,
connection state and duty cycles of Bluetooth devices
in a piconet.
54. 3. Logical Link Control and
Adaptation Protocol (L2CAP)
This layer is responsible for segmentation of large
packets and the reassembly of the fragmented
packets.L2CAP is also responsible for multiplexing of
Bluetooth packets from different applications.
55. 4. Service Discovery Protocol
(SDP)
The SDP enables a Bluetooth device to join a piconet.
Using SDP a device inquires what services are available
in a piconet and how to access them. SDP uses a client-
server model where the server has a list of services
defined through service records. One service record in
a server describes the characteristics of one service. In
a Bluetooth device, they can be only one SDP server. If
a device provides multiple services, one SDP server
acts on behalf of all of them.
56. Bluetooth Security
In a wireless environment where every bit is on the air,
security concerns are high. Bluetooth offers security
infrastructure starting from authentication, key
exchange to encryption. In addition to encryption, a
frequency-hopping scheme with 1600 hops/sec is
employed. All of this makes the system difficult to
eavesdrop.
57. Bluetooth Security
The main security features offered by Bluetooth include a
challenge response routine for authentication, a stream
cipher for encryption, and a session key generation. Each
connection may require a one-way, two-way, or no
authentication using the challenge- response routine. The
security algorithms use the public identity of a device, a
secret private user key, and an internally generated random
key as input parameters. For each transaction, a new
random number is generated on the Bluetooth chip. Key
management is left to higher layer software. The following
figure shows several steps in the security architecture of
Bluetooth.
59. The first step, called pairing, is necessary if two
Bluetooth devices have never met before. To set up
trust between the two devices a user can enter a secret
PIN into both devices. This PIN can have a length of
up to 16 byte. Based on the PIN, the device address,
and random numbers, several keys can be computed
which can be used as link key for authentication. The
authentication is a challenge-response process based
on the link key, a random number generated by a
verifier (the device that requests authentication), and
the device address of the claimat (the device that is
authenticated)
60. Based on the link key, and again a random number an
encryption key is generated during the encryption
stage of the security architecture. This key has a
maximum size of 128 bits and can be individually
generated for each transmission. Based on the
encryption key, the device address and the current
clock a payload key is generated for ciphering user
data. The payload key is a stream of pseudo-random
bits. The ciphering process is a simple XOR of the
user data and the payload key.
62. I. Introduction
Roughly speaking there are two types of wireless
networks:
Local Area Networks (LAN)
Bluetooth, 802.11 Family, HiperLAN Family, HomeRF...
Wide Area Networks (WAN)
GSM, 3G, 4G, Iridium...
64. Two main standards families for Wireless Lan:
IEEE 802.11 (802.11b, 802.11a, 802.11g...)
ETSI Hiperlan (Hiperlan Type 1, Type 2, HiperAccess,
HiperLink...)
HiperLAN Family
Hiperlan 1 Hiperlan2 HiperAccess HiperLink
Description Wireless
Ethernet
Wireless ATM Wireless Local
Loop
Wireless Point-
to-Point
Freq. Range 5GHz 5GHz 5GHz 17GHz
PHY Bit Rate 23.5Mbps 6~54Mbps ~25Mbps
(data rate)
~155Mbps
(data rate)
65. Motivation of HiperLAN
Massive Growth in wireless and mobile
communications
Emergence of multimedia applications
Demands for high-speed Internet access
Deregulation of the telecommunications industry
66. The History, Present and Future
HiperLAN Type 1
Developed by ETSI during 1991 to 1996
Goal: to achieve higher data rate than IEEE 802.11 data rates:
1~2 Mbps, and to be used in ad hoc networking of portable
devices
Support asynchronous data transfer, carrier-sense multiple
access multiple access with collision avoidance (CSMA/CA), no
QoS guaranteed.
Products
Proxim's High Speed RangeLAN5 product family
(24Mbps; 5GHz; QoS guaranteed)
RadioLAN’s products for indoor wireless communication
(10Mbps; 5GHz; Peer-to-Peer Topology)
67. HiperLAN Type 2
Next generation of HiperLAN family: Proposed by ETSI BRAN
(Broadband Radio Access Networks) in 1999, and is still under
development.
Goal: Providing high-speed (raw bit rate ~54Mbps)
communications access to different broadband core networks
and moving terminals
Features: connection-oriented, QoS guaranteed, security
mechanism, highly flexibility
Product: Prototypes are available now, and commercial
products are expected at the end of 2001 (Ericsson).
HiperAccess and HiperLink
In parallel to developing the HIPERLAN Type 2 standards,
ETSI BRAN has started work on standards complementary to
HIPERLAN Type 2
68. Relevant Organizations
Standards body: ETSI (European Telecommunications Standards
Institute, www.etsi.org)
Technology alliance:
HiperLAN2 Global Forum (H2GF, www.hiperlan2.com): promote
HiperLAN Type 2 as a standard, in order to accelerate its use in
business and consumer industries.
OFDM Forum (www.ofdm-forum.com): OFDM is the cornerstone
technology for high-speed wireless LAN such as HiperLAN.
Industry backers: Texas Instruments, Dell, Bosch, Ericsson,
Nokia,Telia, Xircom…
69. Typical application scenarios
HiperLAN: A complement to present-day wireless
access systems, giving high data rates to end-users in
hot-spot areas.
Typical app. Environment: Offices, homes, exhibition
halls, airports, train stations, etc.
Different with Bluetooth, which is mainly used for
linking individual communication devices within the
personal area network
70. II. Hiperlan2 System Overview
Features
5 GHz technology, up to 54 Mbit/s
Generic architecture supporting:
Ethernet, IEEE 1394, ATM, 3G etc
Connection-oriented with QoS per conn.
Security - authentication & encryption
Plug-and-play radio network using DFS
Optimal throughput scheme
71. MAC
CAC
PHY
HiperLAN Type 1 Reference Model
PHY
MAC
EC
ACF DCC
RLC
DLC
CL
HiperLAN Type 2 Reference Model
Control Plane User Plane
MAC: Medium Access Sublayer EC: Error Control
CAC: Channel Access Control Sublayer RLC: Radio Link Control
PHY: Physical Layer RRC: Radio Resource Control
DLC: Data Link Control Layer ACF: Association Control Function
CL: Convergence Layer DCC: DLC Connection Control
Architecture
RRC
72. Physical Layer
Data units on physical layer: Burst of variable
length, consist of a preamble and a data field
Reference configuration
1: information bits
2: scrambled bits
3: encoded bits
4: interleaved bits
5: sub-carrier symbols
6: complex baseband OFDM symbols
7: PHY bursts
73. Spectrum plays a crucial role in the deployment of
WLAN
Currently, most WLAN products operate in the
unlicensed 2.4GHz band, which has several
limitations: 80MHz bandwidth; spread spectrum
technology; interference
Spectrum allocation for Hiperlan2
74. Modulation scheme: Orthogonal frequency-
division multiplexing (OFDM)
Robustness on highly dispersive channels of
multipath fading and intersymbol interference
Spectrally efficient
Admits great flexibility for different
modulation alternatives
Facilitated by the efficiency of FFT and IFFT
algorithms and DSP chips
Hiperlan2: 19 channels (20MHz apart). Each
channel divided into 52 subcarriers
75. Encoding: Involves the serial sequencing of data,
as well as FEC
Key feature: Flexible transmission modes
With different coding rates and modulation schemes
Modes are selected by link adaptation
BPSK, QPSK as well as 16QAM (64QAM) supported
Mode Modulation Code rate Physical layer bit
rate (Mbps)
1 BPSK ½ 6
2 BPSK ¾ 9
3 QPSK ½ 12
4 QPSK ¾ 18
5 16QAM 9/16 27
6 16QAM ¾ 36
7(optional) 64QAM ¾ 54
77. Three main control functions
Association control function (ACF): authentication, key
management, association, disassociation, encryption
Radio resource control function (RRC): handover, dynamic
frequency selection, mobile terminal alive/absent, power
saving, power control
DLC user connection control function (DCC): setup and
release of user connections, multicast and broadcast
Connection-oriented
After completing association, a mobile terminal may request
one or several DLC connections, with one unique DLC
address corresponding to each DLC connection, thus
providing different QoS for each connection
79. BCH (broadcast channel): enables control of radio resources
FCH (frequency channel): exact description of the allocation of
resources within the current MAC frame
ACH (access feedback channel): conveys information on previous
attempts at random access
Multibeam antennas (sectors) up to 8 beams supported
A connection-oriented approach, QoS guaranteed
80. Hiperlan implements QoS through time slots
QoS parameters: bandwidth, bit error rate, latency, and jitter
The original request by a MT to send data uses specific time
slots that are allocated for random access.
AP grants access by allocating specific time slots for a
specific duration in transport channels. The MT then sends
data without interruption from other MT operating on that
frequency.
A control channel provides feedback to the sender.
81. DLC: Error Control
Acknowledged mode: selective-repeat ARQ
Repetition mode: typically used for broadcast
Unacknowledged mode: unreliable, low latency
DLC: other features
Radio network functions: Dynamic frequency selection;
handover; link adaptation; multibeam antennas; power control
QoS support: Appropriate error control mode selected;
Scheduling performed at MAC level; link adaptation; internal
functions (admission, congestion control, and dropping
mechanisms) for avoiding overload
82. III. Comparison with Peers
Main competitor: IEEE 802.11 Family
802.11b vs. HiperLAN Type 1
802.11a vs. HiperLAN Type 2
Pros
High rate with QoS support: Suitable for data and multimedia
app.
Security mechanism
Flexibility: different fixed network support, link adaptation,
dynamic frequency selection…
83. Cons
High cost
Tedious protocol specification
Limited outdoor mobility
No commercial products in market till now
802.11 802.11b 802.11a HiperLAN2
Spectrum (GHz) 2.4 2.4 5 5
Max PHY rate (Mbps) 2 11 54 54
Max data rate, layer 3 (Mbps) 1.2 5 32 32
MAC CS CSMA/CA Central resource
control/TDMA/TDD
Connectivity Conn.-less Conn.-less Conn.-less Conn.-oriented
Multicast Yes Yes Yes Yes
QoS PCF (Point Control
Function)
PCF PCF ATM/802.1p/RSVP/DiffSe
rv (full control)
Frequency selection Frequency-hopping or
DSSS
DSSS Single
carrier
Single carrier with
Dynamic Frequency
Selection
Authentication No No No NAI/IEEE address/X.509
84. 802.11 802.11b 802.11a HiperLAN2
Encryption 40-bit RC4 40-bit RC4 40-bit RC4 DES, 3DES
Handover support No No No To be specified by
H2GF
Fixed Network Support Ethernet Ethernet Ethernet Ethernet, IP, ATM,
UMTS, FireWire
(IEEE 1394), PPP
Management 802.11 MIB 802.11 MIB 802.11 MIB HiperLAN/2 MIB
Radio link quality control No No No Link adaptation
88. Sub-standards of IEEE 802.16
IEEE 802.16.1 - Air interface for 10 to 66 GHz
IEEE 802.16.2 - Coexistence of broadband wireless access systems
IEEE 802.16.3 - Air interface for licensed frequencies, 2 to 11 GHz
89. Basics of IEEE 802.16
IEEE 802.16 standards are concerned with the air interface between a subscriber’s
transceiver station and a base transceiver station
The Physical Layer
MAC Layer
Convergence Layer
91. Physical Layer
Specifies the frequency band, the modulation scheme, error-correction
techniques, synchronization between transmitter and receiver, data rate and the
multiplexing structure
Both TDD and FDD alternatives support adaptive burst profiles in which
modulation and coding options may be dynamically assigned on a burst-by-burst
basis
Three physical layer for services: Wireless MAN-SC2, Wireless MAN-OFDM and
Wireless MAN-OFDMA
92. Medium Access Control Layer
Designed for point-to-multipoint broadband wireless access
Addresses the need for very high bit rates, both uplink (to the base station) and
downlink (from the base station)
Services like multimedia and voice can run as 802.16 MAC is equipped to
accommodate both continuous and bursty traffic
93. Convergence Layer
Provides functions specific to the service being provided
Bearer services include digital audio/video multicast, digital telephony, ATM,
Internet access, wireless trunks in telephone networks and frame relay
94. Reference Network Model
The IEEE 802.16e-2005 standard provides the air interface for WiMAX but
does not define the full end-to-end WiMAX network. The WiMAX Forum's
Network Working Group (NWG), is responsible for developing the end-to-
end network requirements, architecture, and protocols for WiMAX, using
IEEE 802.16e-2005 as the air interface.
The WiMAX NWG has developed a network reference model to serve as an
architecture framework for WiMAX deployments and to ensure
interoperability among various WiMAX equipment and operators.
The network reference model envisions a unified network architecture for
supporting fixed, nomadic, and mobile deployments and is based on an IP
service model.
95. Reference Network Model
The overall network may be logically divided into three parts:
1. Mobile Stations (MS) used by the end user to access the network.
2. The access service network (ASN), which comprises one or more base
stations and one or more ASN gateways that form the radio access network
at the edge.
3. Connectivity service network (CSN), which provides IP connectivity
and all the IP core network functions.
97. Reference Network Model
The network reference model developed by the WiMAX Forum NWG
defines a number of functional entities and interfaces between those entities.
Fig below shows some of the more important functional entities.
1) Base station (BS): The BS is responsible for providing the air interface to
the MS. Additional functions that may be part of the BS are micromobility
management functions, such as handoff triggering and tunnel establishment,
radio resource management, QoS policy enforcement, traffic classification,
DHCP (Dynamic Host Control Protocol) proxy, key management, session
management, and multicast group management.
98. Reference Network Model
2) Access service network gateway (ASN-GW): The ASN gateway typically
acts as a layer 2 traffic aggregation point within an ASN. Additional
functions that may be part of the ASN gateway include intra-ASN location
management and paging, radio resource management and admission
control, caching of subscriber profiles and encryption keys, AAA client
functionality, establishment and management of mobility tunnel with base
stations, QoS and policy enforcement, foreign agent functionality for mobile
IP, and routing to the selected CSN.
99. Reference Network Model
3) Connectivity service network (CSN): The CSN provides connectivity to
the Internet, ASP, other public networks, and corporate networks. The CSN
is owned by the NSP and includes AAA servers that support authentication
for the devices, users, and specific services. The CSN also provides per user
policy management of QoS and security. The CSN is also responsible for IP
address management, support for roaming between different NSPs, location
management between ASNs, and mobility and roaming between ASNs.