- This topic has 25 replies, 1 voice, and was last updated 6 years, 12 months ago by Wallis Dudhnath.
23rd December 2010 at 02:15 #65367Anand SinghGuest
Pls Dear experts explain in details .How the Value of E1=2.048 Mbps comes?23rd December 2010 at 04:27 #65368TanujGuest
32 TS of 64kbps make the e1=2.048Mbps, as 32*64=2048 Kbps or 2.048 Mbps23rd December 2010 at 08:50 #65369BobGuest
Lets go thorough ITU 7.11 or PCM
The original standard for converting analog voice to a digital signal is called pulse-code modulation (PCM).
PCM defines that an incoming analog voice signal should be sampled 8000 times per second by the analog-to-digital (A/D) converter( according to Nyquist’s theorem states that you need twice the number of samples as the highest frequency . As before mentioned the required bandwidth of human’s voice is 4000Hz so 4000×2=8000 samples are needed). A/D converters that are used specifically for processing voice are called codecs (meaning encoder/decoder). For each sample, the codec measures the frequency, amplitude, and phase of the analog signal. PCM defines a table of possible values for frequency/amplitude/phase. The codec finds the table entry that most closely matches the measured values. Along with each entry is an 8-bit binary code, which tells the codec what bits to use to represent that single sample. So PCM, sampling at 8000 times per second finds the best match of frequency /amplitude/phase in the table, finds the matching 8-bit code, and sends those 8 bits as a digital signal. Therefore bit rate can be easily calculated
8bits ×8000samples=64Kbps23rd December 2010 at 08:51 #65370BobGuest
And as a brief conclusion:
In binary with 8 digits.
8000 samples per second
which each sample consists of
8 bits 8000 × 8=64Kbps
For transferring them we need
a media which provide such
DS0: provides one 64kbps channel.
E1: 32 DS0 or 32 channels with 64kbp.
Hope they come in use,
Br25th December 2010 at 15:56 #65371AnandGuest
Actualy i want to know :
1–>(at which voice data rate mobile (MS) transmitter transmit the voice in uplink in air ?)
2–>(what is the voice data rate when the signal is radiated by BTS in air in downlink )
3–>( & how it becomes 2.048 Mbps on E1-connection between BTS & BSC)
Finally–need to know that the mapping of voice data rate in air on E1(=2.048Mbps)26th December 2010 at 11:25 #65372BobGuest
Voice is sent FR-AMR-HR-EFR these are codec in air or between BSS and MS – except HR you can generally consider voice is 16k ,each channel of TS in E1 is 64kbps so each Chanel of E1 can carry 4*16kbps TCH. It means 2 ch of E1 belong to one TRX (just TCH ,not signalling) since TRX creates 8TS in air.now for signalling you can assign 16k,32k or 64kbps in E1 for each TRX.
don’t forget these codec (GSM codec) are changed in Transcoder to PCM(64kbps) it means 16kbps of a tch changes to 64kbps -wow, in 3g very simply you can use TRFO then no needs to adapt the codec , it is a perfect feature, even in 2g if you migrate A interface from TDM to IP , it is possibleto run it. with what being said one E1 in ABIS interface can carry maximum 12 TRX information with 12*32kbps signalling(12*2=24 (for voice)+ 12/2(6 for signalling)=30 +1 omu+1 syn=32). 15 trx is also possible but needs some features
so in uplinke/downlink+ ABIS interface before Transcoder all bit rate are same as MS after Transcoder 64kbps13th October 2011 at 16:41 #65373Sanjay YadavGuest
As we know that voice signal is of frequency 3.3 Khz,and as per the Nyquist Rate or PCM quantization rate for transmission we required signal of >=2f(here ‘f’ is GIF [3.3]=4).and each sample of data is a byte. DS0: provides one 64kbps channel.E1: 32 DS0 or 32 channels with 64kbps
Also we know that voice signal frame consisits of 32 bytes .Hence value of an E1 will be
=2.048Mbps23rd October 2011 at 13:14 #65374AmanGuest
What is the Data rate of signaling of one channel in PCM frame Or E1?28th October 2011 at 14:00 #65375RahulGuest
I need one information on which basis RF engineer decide HR and FR TS4th May 2012 at 14:07 #65376AssefaGuest
Bob and Tanuj explained for you donot you understand!15th May 2012 at 21:53 #65377SriGuest
How many KB’s of GSM data is one DATA erlang?30th May 2012 at 22:25 #65378ZoieGuest
What is threshold for the stacking Erlangs for the Edge data after which you assign one additional time slot for data?28th September 2012 at 21:48 #65379MuthulingamGuest
Please anyone give explanation about LTE ?22nd April 2014 at 08:09 #65380Arun Kumar MishraGuest
As we know one E1 having 32 channel and each channel consist 4 slot of 16kb so 16kb*4*32=2048kbps or 2.048mbps.29th June 2015 at 06:29 #65381SalilGuest
What is the maximum amount of traffic that one signalling link can support?
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