08-17-2017, 12:23 AM
Presented by :
Sanjay Kumar Sethi
[attachment=14497]
TALK FLOW
INTRODUCTION
WHAT IS 3G
HOW 3G WORKS
ADVANTAGES OF 3G
DISADVATAGES OF 3G
WHAT IS WI-FI
HOW IT WORKS
PRODUCTS OF WI-FI
ADVANTAGES WI-FI
DISADVANTAGES WI-FI
CONCLUSION
INTRODUCTION
We are going to compare and contrast two technologies for delivering broadband wireless Internet access services: "3G" and "Wi-Fi".
The former, 3G, refers to the collection of third generation mobile technologies that are designed to allow mobile operators to offer integrated data and voice services over mobile networks .
The latter, WiFi, refers to the 802.11b wireless Ethernet standard that was designed to support wireless LANs
WHAT IS 3G
Wideband CDMA (W-CDMA) : Next Generation GSM.
Uses 5 MHz channel width => 2 Mbps
CDMA2000 : Next Generation CDMA (IS-95)
1.25 MHz Channels => 144 kbps
3x, 6x, 9x and 12x in future
3x (3XRTT) : 3.75 MHz channel => 2 Mbps
UWC-136 : Next Generation TDMA (IS-136)
200 kHz Channels => 384 kbps or
1.6 MHz Channels => 2 Mbps
Developed by Universal Wireless Communications Consortium (UWCC)
Goal : To provide high-speed packet based Voice and Data
3G (3rd Generation)
Also known as ITU IMT-2000 Project started in 1980.
Goal : To have one world-wide standard and a common frequency band for mobile networking
Result : Three frequency bands : Below 1 GHz, 1.7GHz,2.5GHz
Three different technologies :
W-CDMA (Europe)
CDMA2000 (North America)
TD-SCDMA in China.
DATA RATES
HOW IT WORKS
The main principle of 3G is Spread Spectrum communication (W-CDMA principle)
Direct sequence
Frequency hoping
W-CDMA
Short for wide-band CDMA (Code Division Multiple Access), a 3G technology that increases data transmission rates in GSM systems by using the CDMA air interface instead of TDMA.
WCDMA is based on CDMA and is the technology used in UMTS.
WCDMA was adopted as a standard by the ITU under the name "IMT-2000 direct spread".
W-CDMA MAKES POSSIBLE FOR MOBILE MULTIMADIA
DIRECT SEQUENCE PRINCIPLE
FREQUECY HOPING
ADVANTAGES
As the signal is spread over a large frequency band, the power spectral density is getting very small. so other communications systems do not suffer from this kind of communications. However the Gaussian Noise level is increasing.
Random Access can be dealt with, as a large number of codes can be generated a large number of users can be permitted.
The maximal number of users is interference is limited.
Security : without knowing the spreading code, it is (nearly) impossible to recover the transmitted data.
Fading rejection : as a large bandwidth is used the system is less susceptible to distortions.
DISADVANTAGES OF 3G
The cost of upgrading base stations and cellular infrastructure to 3G is very high.
Requires different handsets and there is the issue of handset availability. 3G handsets will be a complex product.
Roaming and making both data/voice work has not yet been demonstrated.
Also the higher power requirements (more bits with the same energy/bit) demand a larger handset, shorter talk time, and larger batteries.
DISADVANTAGES OF 3G continued
Base stations need to be closer to each other (more cost).
Tremendous spectrum-license costs, network deployment costs, handset subsidies to subscribers etc.
Wireless service providers in Germany and Britain who won spectrum licenses in auctions, paid astronomical prices for them. As a result, they have little money left for building the infrastructure. Consequently, deployment of 3G will be delayed.
WHAT IS WI-FI
Almost all wireless LANs are now IEE 802.11 based.
Competing technologies ,e.g. ,hyper LAN can t compete on volume and cost.
802.11 is also known as WI-FI (WIre less FIdelity).
FIDELITY : compatibility between wireless equipment from different manufacturers.
WI-FI alliance is a non profit organization that does the compatibility testing.
ADVANTAGES OF WI-FI
Allows LANs to be deployed without cabling, typically reducing the costs of network deployment and expansion.
Wi-Fi silicon pricing continues to come down, making Wi-Fi a very economical networking option and driving inclusion of Wi-Fi in an ever-widening array of devices.
Wi-Fi products are widely available in the market.
Wi-Fi networks support roaming, in which a mobile client station such as a laptop computer can move from one access point to another as the user moves around a building or area.
Wi-Fi is a global set of standards. Unlike cellular carriers, the same Wi-Fi client works in different countries around the world.
DISADVANTAGES OF WI-FI
Wi-fi can be interrupted by other devices, notably by 2.4 GHz cordless phones.
Power consumption is fairly high compared to some other standards, making battery life and heat a concern.
Wi-Fi networks have limited range.
Wi-Fi networks can be monitored and used to read and copy data (including personal information) transmitted over the network when no encryption such as VPN is used.
CONCLUSION
It remains an open question as to the extent to which these two technologies are in competition or, perhaps, may be complementary.
If they are viewed as in competition, then the triumph of one at the expense of the other would be likely to have profound implications for the evolution of the wireless internet and structure of the service provider industry.