1G 2G 3G 4G 5G
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வயர்லெஸ்ஸின் தாயகம் இந்தியாதான்.
இதைக் கண்டு பிடித்தவர் ஜெகதீஷ் சந்திர போஸ்தான்.
இத்தாலியின் மார்க்கோனி 1895ல் வயர்லெஸ் தகவல்
தொடர்பை முதன் முதலில் செய்து காட்டினார்.
இதற்கு சாமுவேல் மார்ஸின் கோடுகளை பயன்படுத்தினார்.
1G SPEED = 2.4 KBPS analog only voice (check simplex wkg))
commercial use in 1980s
2g speed gprs 50 kbps
edge (9enhanced data rates for gsm evolution = 1 mbps
voice and data (sms)
technology gsm and cdma
gprs = 2.5 g
edge = 2.75 g
3g is umts . umts is core network architecture
imt-2000 spec by itu
speed = atleast 200 kbps
hspa+ 21.6 mbps should bbe
4g = series of improvements in existing umts.
technology = mimo and ofdm orthogonal frequency division multiplexing
two standards : wimaxx and lte
The key technologies that have made this possible are MIMO (Multiple Input Multiple Output) and OFDM (Orthogonal Frequency Division Multiplexing). The two important 4G standards are WiMAX (has now fizzled out) and LTE (has seen widespread deployment). LTE (Long Term Evolution) is a series of upgrades to existing UMTS technology and will be rolled out on Telstra's existing 1800MHz frequency band. The max speed of a 4G network when the device is moving is 100 Mbps or 1 Gbps for low mobility communication like when stationary or walking, latency reduced from around 300ms to less than 100ms, and significantly lower congestion. When 4G first became available, it was simply a little faster than 3G. 4G is not the same as 4G LTE which is very close to meeting the criteria of the standards. To download a new game or stream a TV show in HD, you can do it without buffering .
Newer generations of phones are usually designed to be backward-compatible , so a 4G phone can communicate through a 3G or even 2G network. All carriers seem to agree that OFDM is one of the chief indicators that a service can be legitimately marketed as being 4G. OFDM is a type of digital modulation in which a signal is split into several narrowband channels at different frequencies. There are a significant amount of infrastructure changes needed to be implemented by service providers in order to supply because voice calls in GSM , UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to re-engineer their voice call network. And again, we have the fractional parts: 4.5G and 4.9G marking the transition of LTE (in the stage called LTE-Advanced Pro) getting us more MIMO, more D2D on the way to IMT-2020 and the requirements of 5G .
D2D DISK TO DISK RECOVERY, A BACKUP SOLUTION that copies data from
one hard drve to another
5g
this is currently under development
speed = 35.46 gbps 35 times faster than 4g
key technology: massive mimo, millimeter wave
small cells, li-fi
LiFi (light fidelity) is a bidirectional wireless system that transmits data via LED or infrared light. It was first unveiled in 2011 and, unlike wifi, which uses radio frequency, LiFi technology only needs a light source with a chip to transmit an internet signal through light waves.
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zero g refers to pre cellular mobile telephony.
they are radio telephones.
since they are predecessors to the wireless mobile telephony of
1g they are called 0g.
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now 1g to 5 g
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1g...analog voice calls only wireless mobile communication standard.
2g digital cellular technology permits text messaging
3g faster internet speed.
4g broadband cellular mobile technology. it is the first release of LTE.
5g LATEST; ACHIEVeS MUCH HIGHER DATA RATES.
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speeds 1g to 5 g
1g ... speed upto 2.4 kbps
2g...
3g .... upto 2Mbps (always on data services)
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Wireless dates back to 1895.zero g means pre cellular system. it is invented டூரிங் 1970s prior to
cellular system. it is analog. it is simplex or half duplex working.
at a time one alone can speak. so at the end of the every spell of the
talk, one has to say over over. No roaming in 0g. it is highly
localized. local telephone network will connect to it iff it is
within the range of 20 km distance. this is all about 0g. 0g is wireless.
கார்களிலும் ஜீப்களிலும் அவற்றின் தலைப்பகுதியில்
ஒட்டுமொத்த 0g கருவி பொருத்தப் பட்டிருக்கும்.
ஓவர் ஓவர் என்று சொல்லிக்கொண்டே போலீஸ்காரர்கள்
வயர்லெஸ்ஸில் 0gயில் பேசுவதை நம்மில் பலரும்
கேட்டிருப்போம். 0g is analog and wireless.
1g.... standard is introduced in 1980. It is analog and wireless.
it used fdma frequency division multiple access.
multiple access என்றால் என்ன? பல்பயன்பாடுதான்.
voice calls frequency modulation செய்யப்படும்.
150 MHz FREQUENCY க்கு CALLS உயர்த்தப்படும்.
2G.......
2G works in the technology called gsm
global system for mobile communication
2g was first launched in finland in 1991.
இந்தியாவில் 1995ல்தான் முதன் முதலில் மொபைல்
போன் வந்தது. நரசிம்மராவ் பிரதமர் சுக்ராம்
தொலைத்தொடர்பு அமைச்சர். முதல் மொபைல் பேச்சு
ஜோதிபாசு சுக்ராம் இருவரிடையே கொல்கொத்தா டெல்லி
31 ஜூலை 1995ல் நடைபெற்றது. முதலில் பேசியவர்
ஜோதிபாசு, the caller.
2g used tdma or cdma technology.
tdma = time slots
2g = mainly voice and sms
2.5 g = gprs 5.6 kbps to 115 kbps
2.75 = only gsm.
speed = upto 384 kbps
3g.....
japan was the first country to launch 3g in 2001.
imt-2000 given by itu.
this familly includes 3.5g அண்ட் 3.75g
3,5g.......
HSDPA HIGH SPEED DOWNLINK PACKET ACCESS.
DATASPEED 8 TO 10 MBPS
3.7G...........
HSUPA HIGH SPEED UPLINK PACKET ACCESS
mobile e mail, p2p gaming real time
speed 1.4 mbps to 5.8 mbps
note: since it is uplink the speed is less then 3.5 g.
4g.......
packet switched
technology ofdm orthogonal frequeny division multiplexing
uwb ultra wide radio band millimeter wave
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c band ku bband etc
satellite frequency bands
With the variety of satellite frequency bands that can be used, designations have been developed so that they can be referred to easily.
L-band (1–2 GHz)
Global Positioning System (GPS) carriers
S-band (2–4 GHz)
Weather radar, surface ship radar, and some communications satellites, especially those of NASA
C-band (4–8 GHz)
Primarily used for satellite communications, for full-time satellite TV networks
X-band (8–12 GHz)
Primarily used by the military. Used in radar applications
Ku-band (12–18 GHz)
Used for satellite communications. In Europe, Ku-band downlink is used from 10.7 GHz to 12.75 GHz for direct broadcast satellite services, such as Astra.
Ka-band (26–40 GHz)
Communications satellites, uplink in either the 27.5 GHz and 31 GHz bands, and high-resolution, close-range targeting radars on military aircraft.
KU BAND WAVE LENGTH = 2.5 TO 1.67 CM----
FOR IRNSS ISRO USES L5 AND S BANDS.
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