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MCOMMERCE

MCOMMERCE. TOPICS TO BE DISCUSSED. 1.WIRELESS DELIVERY TECHNOLOGY RADIO-BASED SYSTEMS CELLULAR COMMUNICATION LIGHT BASED MOBILE COMPUTING BLUETOOTH-BASED MOBILE COMPUTING 2.WIRELESS CHANNEL MULTIPLEXING TDMA CDMA COMPARISON…. RADIO-BASED SYSTEMS.

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MCOMMERCE

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  1. MCOMMERCE

  2. TOPICS TO BE DISCUSSED 1.WIRELESS DELIVERY TECHNOLOGY • RADIO-BASED SYSTEMS • CELLULAR COMMUNICATION • LIGHT BASED MOBILE COMPUTING • BLUETOOTH-BASED MOBILE COMPUTING 2.WIRELESS CHANNEL MULTIPLEXING • TDMA • CDMA • COMPARISON…

  3. RADIO-BASED SYSTEMS • Wireless communications services radio, cellular, satellite and paging involve radio frequency(RF) SIGNALS THAT TRAVEL OVER FREQUENCIES FROM 100 KHz to 20 GHz. • RF signals comes in two flavors  local area RF and wide area RF. • RF communications are of two types that is one way, two way and local.

  4. CELLULAR COMMUNICATION • A cell in a cellular system is a roughly circular area with a central transmitter/receiver base station.The station is raised up on a tower or placed on top of building. • Communications take place through a grid of transmitters and receivers, each one called a cell. • Frequencies are divided into cell bands with a buffer zone to prevent interference or jamming of neighbouring cell’s frequencies. • When a user turns a phone on, its phone number and serial number are broadcast within the local cell.

  5. LIGHT BASED MOBILE COMPUTING • Infrared works by sending pulses of light from a light emitting diode(LED) to a photo sensor that decodes the signals. • Most infrared equipment falls into two categories  low speed devices and high speed devices. • One of the best feature of infrared is its price. • Infrared is still not as fast as many cable connections but it is fine for updating files, downloading schedule or transmitting other data.

  6. BLUETOOTH-BASED MOBILE COMPUTING • The working of Bluetooth is based on the radio specifications to enable file sharing and data transfers between devices like a PDA and a Desktop. • It is Omni-directional and has a present nominal range of 10 cm to 10 m. • Bluetooth operates on a globally available low radio frequency at 2.4 GHz. • It ensures point to multipoint connection.

  7. TDMA • TDMA stands for time division multiple access. • It uses time division multiplexing technology that squeezes three calls onto a single 30 kHz transmission channel. • Calls are given separate time slots on a frequency, layered in between other signals and transported from cell site to cell site. • In TDMA, the radio channel is divided so that the user can transmit information in unique time slots, letting multiple users share a channel. • Quality of signal received by user is good, but the user has to wait for his turn.

  8. CDMA • CDMA stands for Code division multiple access. • CDMA is called as spread spectrum. • CDMA is a wideband spread spectrum technology that spreads multiple conversations across a wide segment of the cellular broadcast spectrum. • Each data call is assigned a unique code that permits it to be distinguished from the massive amount of calls simultaneously transmitted over the same broadcast spectrum.

  9. COMPARISON… TDMA CDMA Suitable for adhoc networking Not suitable for adhoc networking Limited spectrum Wider spectrum than TDMA TDMA shares equipment CDMA increases equipment required per call CDMA transmits continuously at low power TDMA transmits only during Assigned burst periods CDMA is adopted for 3G mobile phone technology TDMA is used by GSM

  10. THANKS….

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