gsm interleaving
Interleaving
Interleaving is used to obtain time diversity in a digital communications system without
adding any overhead. The interleaving decreases the possibility of losing whole bursts
during the transmission. The interleaving scheme used for the speech channel is
described in the following paragraph.
The total of 456 bits from the convolutional encoder, which constitutes 20ms of speech,
is subdivided into eight blocks of 57 bits each. These eight blocks are then transmitted in
consecutive time slots. If one of the blocks is lost due to burst errors, the other 7 blocks
would contain enough information so that whole segment can be recovered using error
correction. Each time slot carries two 57-bit sub-blocks of data from two different 20ms
speech segments.
Re: GSM Interleaving
Interleaving is the processes of rearranging the bits. Interleaving allows the error correction algorithms to correct more of the errors that could have occured during transmission. By interleaving the code, there is less possibility that a whole chuck of code can be lost.
visit http://www.azizi.ca/gsm/system/index.html
and
http://www.cs.ucl.ac.uk/staff/t.pagtzis/wireless/gsm/radio.html
for a detailed explanation
Guru
Re: GSM Interleaving
What are the freequency bands in GSM
Re: GSM Interleaving
GSM is a digital cellular phone technology based on TDMA that is the predominant system Europe, the Middle East, Africa, Asia and in parts of America and Canada. First introduced in 1991, the GSM standard has been deployed at three different frequency bands: 900 MHz, 1800 MHz and 1900 MHz. GSM 1900 is primarily deployed in North America. Named after its frequency band around 900 MHz, GSM-900 has provided the basis for several other networks using GSM technology. GSM uses narrowband TDMA which allows eight simultaneous calls on the same radio frequency. Along with CDMA and TDMA it represents the second generation of wireless networks.
Re: GSM Interleaving
GSM 1800
Also known as DCS 1800 or PCN, GSM 1800 is a digital network working on a frequency of 1800 MHz. It is used in Europe, Asia-Pacific and Australia.
GSM 1900
Also known as PCS 1900, GSM 1900 is a digital network working on a frequency of 1900 MHz. It is used in the US and Canada and is scheduled for parts of Latin America and Africa.
GSM 900
The world’s most widely used digital network and now operating in over 100 countries around the world, particularly in Europe and Asia Pacific.
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