Hi all
please let me know the difference in these for wireless systems......and please also notify the advancements made in respect to the other or older techniques....like GPRS has a better modulation tech than the GSM, but i actualy dont realy know of it......so please mention the details.....with respect to modulation....coding.....multiplexing....channels..... thanx all
Hi,
To answer your query in smart way, GSM, EDGE, CDMA all belong to 3GPP evolution. The first and most popular from the above said is GSM technology.
GPRS, SMS etc., are the value added services that they provide. The EDGE is for enhancement of data rate for data services in GSM. EDGE is compatible with all existing GSM systems. The only difference is data rate, it is achieved by increasing the number of bits in one symbol. In GSM for a symbol duration of 3.7 micro seconds one bit is transmitted, whereas in EDGE for the same symbol duration three bits are transmitted. In terms of modulation GSM uses GMSK modulation where as EDGE uses modified 3pi/8 8psk with linearised Gaussian pulse shaping.
In terms of RF power envelope , GSM is constant envelope, whereas EDGE has non-constant envelope.
The above said is difference between GSM and EDGE technology only in basic terms. For more details you can visit www.3gpp.org.