This document discusses multiplexing techniques used in mobile computing. It describes four types of multiplexing: frequency division multiplexing (FDM), time division multiplexing (TDM), code division multiplexing (CDM), and space division multiplexing (SDM). For each type, it provides details on how the technique works and its advantages and disadvantages. FDM uses different frequencies to transmit multiple signals simultaneously. TDM divides a signal into time slots to share a frequency. CDM assigns unique codes to signals sharing the same frequency. SDM splits a channel across physical locations.
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
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.
Motivation for a specialized MAC (Hidden and exposed terminals, Near and far terminals), SDMA, FDMA, TDMA, CDMA, Wireless LAN/(IEEE 802.11)
Mobile Network Layer: IP and Mobile IP Network Layers, Packet Delivery and Handover Management, Location Management, Registration, Tunneling and Encapsulation, Route Optimization, DHCP
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
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.
Motivation for a specialized MAC (Hidden and exposed terminals, Near and far terminals), SDMA, FDMA, TDMA, CDMA, Wireless LAN/(IEEE 802.11)
Mobile Network Layer: IP and Mobile IP Network Layers, Packet Delivery and Handover Management, Location Management, Registration, Tunneling and Encapsulation, Route Optimization, DHCP
Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. The three channelization protocols are FDMA, TDMA, and CDMA
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between adjacent network nodes in a wide area network (WAN) or between nodes on the same local area network (LAN) segment.
Coda (Constant Data Avaialabilty) is a distributed file system developed at Carnegie Mellon University . This presentation explains how it works and different aspects of it.
The network layer is responsible for routing packets from the source to destination. The routing algorithm is the piece of software that decides where a packet goes next (e.g., which output line, or which node on a broadcast channel).For connectionless networks, the routing decision is made for each datagram. For connection-oriented networks, the decision is made once, at circuit setup time.
Routing Issues
The routing algorithm must deal with the following issues:
Correctness and simplicity: networks are never taken down; individual parts (e.g., links, routers) may fail, but the whole network should not.
Stability: if a link or router fails, how much time elapses before the remaining routers recognize the topology change? (Some never do..)
Fairness and optimality: an inherently intractable problem. Definition of optimality usually doesn't consider fairness. Do we want to maximize channel usage? Minimize average delay?
When we look at routing in detail, we'll consider both adaptive--those that take current traffic and topology into consideration--and nonadaptive algorithms.
Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. The three channelization protocols are FDMA, TDMA, and CDMA
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between adjacent network nodes in a wide area network (WAN) or between nodes on the same local area network (LAN) segment.
Coda (Constant Data Avaialabilty) is a distributed file system developed at Carnegie Mellon University . This presentation explains how it works and different aspects of it.
The network layer is responsible for routing packets from the source to destination. The routing algorithm is the piece of software that decides where a packet goes next (e.g., which output line, or which node on a broadcast channel).For connectionless networks, the routing decision is made for each datagram. For connection-oriented networks, the decision is made once, at circuit setup time.
Routing Issues
The routing algorithm must deal with the following issues:
Correctness and simplicity: networks are never taken down; individual parts (e.g., links, routers) may fail, but the whole network should not.
Stability: if a link or router fails, how much time elapses before the remaining routers recognize the topology change? (Some never do..)
Fairness and optimality: an inherently intractable problem. Definition of optimality usually doesn't consider fairness. Do we want to maximize channel usage? Minimize average delay?
When we look at routing in detail, we'll consider both adaptive--those that take current traffic and topology into consideration--and nonadaptive algorithms.
In internetworking, Multiplexing is a process in which multiple data.pdfanupambedcovers
In internetworking, Multiplexing is a process in which multiple data channels are combined into
a single data or physical channel at the source. Multiplexing can be implemented at any of the
OSI layers. Conversely, demultiplexing is the process of separating multiplexed data channels at
the destination. In this way student data & class assignment data can be combined & separated.
Types of Multiplexing
There are two basic forms of multiplexing used:
Time Division Multiplexing
Time Division Multiplexing works by the multiplexor collecting and storing the incoming
transmissions from all of the slow lines connected to it and allocating a time slice on the fast link
to each in turn. The messages are sent down the high speed link one after the other. Each
transmission when received can be separated according to the time slice allocated.
Theoretically, the available speed of the fast link should at least be equal to the total of all of the
slow speeds coming into the multiplexor so that its maximum capacity is not exceeded.
Two ways of implementing TDM are:
Synchronous TDM
Synchronous TDM works by the muliplexor giving exactly the same amount of time to each
device connected to it. This time slice is allocated even if a device has nothing to transmit. This
is wasteful in that there will be many times when allocated time slots are not being used.
Therefore, the use of Synchronous TDM does not guarantee maximum line usage and efficiency.
Synchronous TDM is used in T1 and E1 connections.
Asynchronous TDM
Asynchronous TDM is a more flexible method of TDM. With Asynchronous TDM the length of
time allocated is not fixed for each device but time is given to devices that have data to transmit.
This version of TDM works by tagging each frame with an identification number to note which
device it belongs to. This may require more processing by the multiplexor and take longer,
however, the time saved by efficient and effective bandwidth utilization makes it worthwhile.
Asynchronous TDM allows more devices than there is physical bandwidth for.
This type of TDM is used in Asynchronous Transfer Mode (ATM) networks.
Frequency Division Multiplexing
Frequency Division Multiplexing (FDM) works by transmitting all of the signals along the same
high speed link simultaneously with each signal set at a different frequency. For FDM to work
properly frequency overlap must be avoided. Therefore, the link must have sufficient bandwidth
to be able to carry the wide range of frequencies required. The demultiplexor at the receiving end
works by dividing the signals by tuning into the appropriate frequency.
FDM operates in a similar way to radio broadcasting where a number of different stations will
broadcast simultaneously but on different frequencies. Listeners can then \"tune\" their radio so
that it captures the frequency or station they want.
FDM gives a total bandwidth greater than the combined bandwidth of the signals to be
transmitted. In order to prevent signal overlap t.
The tutorial is designed for all those readers who are planning or pursuing the CDMA course to make their career in this field. However, it is also meant for the common readers who simply want to understand − what is CDMA Technology?
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
2. Content:
What is multiplexing ?
Types of multiplexing in mobile computing
Advantages
Disadvantages
Uses of multiplexing in mobile computing
3. What is multiplexing ?
It is the set of techniques that allows the simultaneous
transmission of multiple signals across a single data link.
Multiplexing is done using a device called Multiplexer (MUX)
that combine n input lines to generate one output line i.e. (many
to one).
At the receiving end a device called Demultiplexer (DEMUX)
is used that separate signal into its component signals i.e. one
input and several outputs (one to many).
4. Types of Multiplexing
Frequency Division Multiplexing (FDM)
Time Division Multiplexing (TDM)
Code Division Multiplexing (CDM)
Space Division Multiplexing (SDM)
5. Frequency Division Multiplexing
FDM is inherently an analog technology.
It is a method of multiplexing by which multiple number of
information are in different frequency.
FDM’s most common applications are traditional radio,
television broadcasting , mobile or satellite stations, cable
television
6.
7. Advantages of FDM
1. The concept of frequency division multiplexing (FDM)
applies to both analog signals and digital signals.
2. It facilitates you to send multiple signals simultaneously
within a single connection.
Disadvantages of FDM
1. It is less flexible.
2. In FDM, the bandwidth wastage may be high.
8. Time Division Multiplexing
It is a method in which the multiple number of information are
communicate with in a different slot of time.
The Time frames of the same intervals are divided so that you
can access the entire frequency spectrum at that time frame.
This method is used in telegraphy or in ISDN telephonic
services.
9.
10. Advantages of TDM
1. It facilitates a single user at a time.
2. It is less complicated and has a more flexible architecture.
Disadvantages of TDM
1. It isn't easy to implement.
11. Code Division Multiplexing
It is a method of multiplexing in which multiple number of
information are multiplex in different code .
The Code Division Multiplexing or (CDM) allots a unique
code to every channel so that each of these channels can use
the same spectrum simultaneously at the same time.
It is mainly used in Cell Phone Spectrum Technology (2G, 3G
etc.)
12. Advantages of CDM
1. It is highly efficient.
2. It faces fewer Inferences.
Disadvantages of CDM
1. The data transmission rate is low.
2. It is complex.
13. Space Division Multiplexing
SDM is a method in which we split a communication channel
into multiple different physical location and allocated each stream
of data onto each of the location.
It is a combination of FDM and TDM.
It passes messages or data-parallel with the use of specific
frequency at a specific. It means a particular channel will be used
against a specific frequency band for some amount of time.
It is used in GSM (Global Service for Mobile) Technology
14. Advantages of SDM
1. In SDM, the data transmission rate is high.
2. It uses Time and Frequency bands at its maximum potential.
Disadvantages of SDM
1. An inference may occur.
2. It faces high inference losses.
