Two Main Types of Cellular Wan - Gsm and Cdma
Essay by Greek • December 11, 2011 • Essay • 346 Words (2 Pages) • 1,831 Views
Two main types of Cellular WAN
Global System for Mobile (GSM)
GSM is the world's most used mobile wireless communication network as it dominated the Euro-Asia markets and is slowly taking over North America with companies like A& T in the USA using it. How it works is it uses a narrow 30khz band 30 which splits time-wise into three time slots this allows information to be significantly compressed this technology is called TDMA and has three times more capacity than the traditional analog. Bell Canada has recently launched their new 4G LTE in a number of regions in Ontario this past month in which they claim the network will be up to 3 times faster than the original CDMA HSPA+ technology they introduced just 3 years ago. Bell states that initial speeds will be up to 75MBPS with average speeds of 12-25 MBPS and as the technology evolves speeds will approach 150 MBPS. The frequency will still be at the Band 2 level which is 1900MHZ. The greatest strength of GSM over CDMA is that you can travel almost anywhere in the world permitting roaming charges and it also uses encryption so calls are more secure too.
Code-Division Multiple Access (CDMA)
CDMA is a wireless network which found its roots during the second world war but wasn't commercially launched until the mid 90's. So how CDMA works is it digitizes multiple conversation, attaching a code that only the sender and receiver know, and then it chops up the signal and reassembles it using the code. Doing this makes it very secure. The frequency it operates at in Canada is 1900MHZ and 850MHZ most phones operate at the 1900 level but 850 is put to use when you're in more rural areas for instance somewhere in the interior of BC. Bell Canada's 4g HSPA+ which is offered throughout most of Canada currently has speeds of 21MBPS to 42 MBPS depending on locations. Downfalls of the CDMA system include its inability to offer international roaming and the fact that CDMA is a relatively newer technology it hasn't fully matured.
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