Design Issues and Challenges in Wireless Sensor NetworksKhushbooGupta145
Wireless Sensor Networks (WSNs) are composed self-organized wireless ad hoc networks which comprise of a large number of resource constrained sensor nodes. The major areas of research in WSN is going on hardware, and operating system of WSN, deployment, architecture, localization, synchronization, programming models, data aggregation and dissemination, database querying, architecture, middleware, quality of service and security. This paper study highlights ongoing research activities and issues that affect the design and performance of Wireless Sensor Network.
Design Issues and Challenges in Wireless Sensor NetworksKhushbooGupta145
Wireless Sensor Networks (WSNs) are composed self-organized wireless ad hoc networks which comprise of a large number of resource constrained sensor nodes. The major areas of research in WSN is going on hardware, and operating system of WSN, deployment, architecture, localization, synchronization, programming models, data aggregation and dissemination, database querying, architecture, middleware, quality of service and security. This paper study highlights ongoing research activities and issues that affect the design and performance of Wireless Sensor Network.
A Brief Knowledge about Differential Pulse Code Modulation.
It contains the basics of Pulse Code modulation and why we all switching to Differential Pulse Code Modulation.
All the things about the Differential Pulse Code Modulation is given in a good understandable way
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
Modem = modulator + demodulator.
A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.
It is one of my semester project presentation along with my group members, of subject Data Communication, which covers a brief intro about all the vital things related to the modems.
A Brief Knowledge about Differential Pulse Code Modulation.
It contains the basics of Pulse Code modulation and why we all switching to Differential Pulse Code Modulation.
All the things about the Differential Pulse Code Modulation is given in a good understandable way
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
Modem = modulator + demodulator.
A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.
It is one of my semester project presentation along with my group members, of subject Data Communication, which covers a brief intro about all the vital things related to the modems.
You have a small business customer who wants to use a voice over IP .pdfAroraRajinder1
You have a small business customer who wants to use a voice over IP (VoIP) system and
subscribe to this service through his ISP using DSL. What special piece of equipment will need
to be installed to provide analog-to-digital signal conversion between the phones and the digital
network?
A. A cable modem
B. A DSL modem
C. An Integrated access device (IAD)
D. A multimedia terminal adapter (MTA)
Solution
a cable modem is anetwork bridge and modem connects bi-directional data communication radio
frequncy channel on a hybrid fibar co axial and radio frequncy over glass infra structure.
A digital subscriber line (DSL) modem is a device used to connect a computer or router to a
telephone line which provides the digital subscriber line service for connectivity to the Internet.
An Integrated Access Device (or IAD) is a customer premises device that provides access to
wide area networks and the Internet.
A multimedia terminal adapter (MTA), or Home Phone modem, operates much the same as a
cable modem, but an MTA can deliver Home Phone service in addition to High Speed Internet.
so answer is B. A DSL Modem.
In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment, originally defined as data communication equipment[1]), such as a modem. The RS-232 standard is commonly used in computer serial ports. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997.
2. External Cable Modems a small box that can provide a computer with an Internet connection through either usb or ethernet. most cable modems do come with USB ports installed as well as the usual Ethernet port
3. Internal Cable Modems Internal cable modems come in form of a PCI (Peripheral Component Interconnect) bus card for PC's Disadvantage: If cable modem is powered down just itself, computer would be powered down as well
4. Set Top Box Integrated Cable Modems Commonly used for services like interactive TV and Internet via your television Many companies use this type of cable modem to supply Internet access to your computer
5. Downstream/Upstream Downstream data is transmitted from the Internet towards the computer that requested it Upstream data is data that is sent or "uploaded" from a computer towards the Internet http://www.tvcinc.com/products/cm550.jpg
6. CATV Infrastructures Cable Access Television, sometimes known as Community Antenna Television Modems use CATV infrastructures that partly consist of HFC (Hybrid Fibre-Coax) http://www.microsens.pl/gifs_all/catv_node.gif
8. Tuner Connects to the CATV outlet Digital modulated signals and then forwards them towards the demodulator Can be attached to a diplexer, which enables the tuner to use a range of frequencies for both the downstream and upstream traffic
9. Demodulator Four main functions: QAM (Quadrature Amplitude Modulation) A/D converter (Analog to Digital) Error correction MPEG (Moving Picture Experts Group) synchronizer
10. Demodulator (Cont’d) QAM takes radio-frequency signal and changes it so the A/D converter can process it A/D converter converts signal into a digital signal of 0's and 1's Error correct module then compares the data received to a known standard, fixing errors in transmission MPEG synchronizer is then used to sequence and organise data groups into their correct order
11. Modulator Three main functions: To insert data that is ready for error correction QAM (Quadrature Amplitude Modulation) D/A conversion (digital to analog)
12. Modulator (Cont’d) AKA Burst modulator Converts digital data back into analog radio frequency signals so that they are ready for transmission
13. MAC (Media Access Control) Acts as the interface between parts of various network protocols Either the CPU of the cable modem or the CPU of the computer is used to take some pressure away from the MAC because of the complexity of its functions.
14. CPU (Central Processing Unit) The brain that controls all of the activity inside the cable modem itself www.novopc.com
