PRESENTS

100’S OF TELECOM…

Imthiyaz Ali .A RF OPTIMIZER

DO U KNOW 1 THING ???? 1.In 1876,Alexender graham bell invented telephone.

2.The original name of telephone was Harmonic telegraph.

3.In 1887, Heinrich Rudolf hertz (Germany) discovered radio waves.

4.Gulielmo marconi is the father of wireless technology.

5.In 1901,marconi send the first wireless signal.

6.In 1934,Alec Reeves invented PCM-method to convert analog signal to digital signal.

7.In 1964,Roger Easton invented GPS.

8.Alexander graham bell originally wanted the greeting for the telephone to be “Ahoy”.

9.Don green is nicknamed the “Father of telecom valley”

10.In 1969,Don green founded Digital telephone system(DTS),in Novato(california).

11.President Ruther ford B.Hayes(1877-1881) was first to have phone service.

12.In august 4,1922 Alexander graham bell died.

13.When Alexander graham bell was died millions of phones in USA and Canada served by Bell company were shutdown for one minute in Bell’s honor.

14.George Antheil and Hedy Lamarr(1914-2000)are the inventor and composer of Frequency Hopping.

15.First cell phone weighed 21bs.

16.Alfred J.gross(Feb 2,1918-Dec21,2000)was a pioneer in mobile wireless communication.

17.In 1963,the first geo-stationery satellite was launched for supporting global communications.

18.In 1900,first coin telephone was installed.

19.In 1914,the first coast to coast phone line was established.

20.The dial tone of telephone is in the musical key of F.

21.In 1968,first 911 system was introduced in the united states.

22.Canadian National(CN)tower,toronto(1975),was the tallest telecommunication tower of ht 553m.

23.The British telecom communication tower in London's west end was the first purpose built tower to transmit high frequency radio waves.

24.In august 1995,GSM entered India.

25.In 1989-The telecom commission was constituted.

26.In January 1997-TRAI was formed.

27.In July 31,1995 west Bengal chief minister(B.K Modi group) made India's first cellular phone call.

28.In 1947,the cells for mobile phone base station was introduced by Bell labs engineers at AT&T.

29.In 1946,first commercial mobile phone were installed in st.Louis.

30.In 1st October 2000,the BSNL department was created as a public sector.

31.In 1973,first mobile phone call was made" Hi Joel guess where I'm calling from”.

32.Dr.Martin cooper, is consider the inventor of the first modern portable handset.

33.On July 1,1991,Finnish prime minister Harri holkeri made the world’s first GSM call.

34.The telephone is the most profitable invention in US history.

35.The annual revenue for the telephone industry is $210 billion, almost 8 times that of television and 23 times the revenue of radio.

36.Globally, about $1 trillion is spent annually on telecommunication products and services.

37.The busiest organization in the world is pentagon which has 34,500 lines and gets 1million calls a day.

38.The busiest telephone exchange was by Bellsouth at the Olympic games, where 100 billion bits of information are transmitted per second.

39.The longest phone cable is a submarine cable called FLAG, it spans 16,800 miles from Japan to the united kingdom and can carry 600,000 calls at a time.

40.In April 1950,the number of telephone exchanges absorbed from princely states was 196.

41.Military radios use cryptographic techniques to generate the channel sequence under the control of secret transmission key(TRANSE)that the sender and receiver share.

42.One million threads of fiber optic cable can fit in a tube ½’ diameter.

43.It is possible to carry more than 28 million separate and simultaneous phone conversation on just one optical fiber.

44.In 1966,an experimental optical fiber system had an information carrying capacity of about 200TV channels(more than 200,000 telephone calls).

45.Fiber optic connections are essentially “Data super highways", in that they can carry 10’s of millions of bits of data per second.

46.The core center of an optical fiber, the part that actually carries the communication signals, is half a thick as an human hair.

47.The transmission power in the handset is limited to a maximum of 2 watts in GSM 850/900 and 1watt in GSM 1800/1900.

48.GSM uses several cryptographic algorithm for security.

49.The A5/1 and A5/2 stream ciphers are used for ensuring over the air voice privacy.

50.KI-The crypto variable stored on the SIM card that is the key to any GSM ciphering algorithm is never send over air interface.

51When audio devices are near field of the GSM handset, the radio signals is strong enough that the solid state amplifier in the audio chain functions as a detector(crack noise), this can be eliminated by using a by pass capacitor in the audio devices.

52.The voltage applied to the telephone is related to the distance at which the telephone can be operated.

53.Due to electrolysis the positive voltage on copper wire makes copper to age quickly. the reason for electing -48v in reference to ground is to avoid the nasty galvanic effects in telephone cabling.

54.Ki-the ki is the 128 bit individual authentication key.

55.The modulation used in GSM is Gaussian Minimum shift keying(GMSK)-a kind of continuous phase frequency shift keying.

56.Global system for mobile communication(GSM) was developed by European telecommunication standard institute(ETSI).

57.The longest distance the GSM specification supports in practical use is 35km or 22 miles.

58.Out of world population of 6.32 billion people, approximately 1.12 billion, or 1 in 6,have a mobile phone and 71.6% are GSM customers.

59.About 2 billion people in the world have yet to make a phone call.

60.In slow frequency hopping -217 hopes per second.

61.The overall bandwidth required for frequency hopping is much wider than that required to transmit the same information using only one carrier frequency.

62.GSM modulation speed 270.833 kb/s.

63.Adaptive mean ratio:

Full rate- 13.6kbps

Half rate- 4.6kbps/9.2kbps

64.In RF planning Raleigh fading is taken in account by implementing an extra fade margin of 8db.

65.If the reflected wave is 180 out of phase to that of the direct path, the signal may disappear.

66.Doppler shift affects multiple propagation loss it can be limited by using a adaptive equalized in receiver.

67.Using jakes graphs we can calculate appropriate fade margin.

68.FH gain with @ 2% of FER.

69.Only when SABM and UA is seen in Layer 2 message handover is said to be success.

70.Cell coverage area: omni cell-2.6R*R Sector cell-1.96R*R.71.PBGT handover – most healthy handover in network.72.Total system quality gets reduced with high mobile speed > 30km/h.73.Hopping over 8 frequencies provide -3db improvement.74.MAIO offset avoid co-channel and adjacent channel collision between cells inside the site.75.MAIO step avoid adjacent channel collision between the TRX in side the cell.76.Handover margin: power budget handover - 4-6db. level handover-3db. quality handover-0db.77.Physical channels: GSM900-992 channels. GSM1800-374channels. GSM1900-299channels.

78.KPI-key performance indicators, has a benchmark of accessability,retainability,mobility,integrity.

79.Frame erasure rate(FER),is the right measure of voice quality.

80.Maximum 63 bit times can be used in GSM.

81.A minimum of 156.25 bits can be transmitted in each time slot.

82.MS uplink HSN is same as the TRX downlink HSN but offset by 45

83.DTX is achieved by use of a Voice activation device(VAD) incorporated in to the MS handset, when no speech is detected the speech rate is reduced from 13kbps to 500bps.

84.Adaptive power control is compulsory in MS but optional in BTS.

85.There are 32 power level separated by 2dbm,one 2db step change every 60ms.

86.A transcoder sub multiplexer(TCSM)can change bit rate of 64kbps to 16kbps.

87.Number of carriers:DCS1800-374carriers.

GSM900-124carriers.

88.System information are sent at least after every 1.8sec.

89.Three satellite can cover the entire earth,e.g-Intelsat,Symphonie,Molniya.

90.Communication satellite has a life of 7-10 years.

91.There is a roundtrip satellite transmission delay of 500 milli sec in the IP cloud.

92.Maximum vehicle speed (Vm)-250km/h.

93.A BSC can control up to 40 BTS.

94.Maximum of 24 Twin TRX can be adopted for a base station cabinet.

95.India has more than 1,50,000 route km of microwave system deployed in the country.

96.RF has also caused leukemia in children,headache,neurological changes, loss of memory, increased blood pressure, and damage to eye cell.

97.In 2005,the Pakistan nuclear regulatory authority(PNRA) has informed that the radio frequency fields are Non-ionizing and dose not cause significant stochastic.

98.Airtel controls 21.4% subscriber base followed by Reliance with 20.3%, BSNL with 18.6%, Vodafone with 14.7% subscriber base (as per June 2005 data).

99.GSM subscriber figure till Jan 2009: Bharti Airtel -88382758,33.04%

Vodafone Essar- 63340024,23.68% BSNL -42673357,15.95% IDEA -40016153,14.96% Aircel -16761397,6.27%

Reliance Telecom -10353841,3.87% MTNL -4003807,1.50%

BPL -2007303,0.75%All India- 267538640

100. - In time… All time…

TO BE CONTINUED…..

(imthiyazece@sify.com)