TDMA - Time Division Multiple Access
-Sorts messages into time slots in order to send them.
-Voice and data are converted to digital signals that are sent and received in bursts in specific time slots.
CDMA - Code Division Multiple Access
-Was developed by Qualcomm for military anti jamming systems, which translates into highly private conversations.
-It spreads a low power signal across a wide frequency width, which provides for a significant increase in subscriber capacity.
GSM - Global System for Mobile Communications
-Was originally developed in Europe and works similarly to the TDMA system: it sorts messages into time slots.
-The unique feature of this technology is that it allows for a short message service, up to 124 characters, while simultaneously carrying voice traffic.
The GSM Association is an international organization founded in 1987, dedicated to providing, developing, and overseeing the worldwide wireless standard of GSM.
Comaprison - -
To be exact, GSM stands for Global System for Mobile Communications, which is based on an older standard called TDMA.CDMA stands for Code Division Multiple Access. GSM allocates a bit of bandwidth for each user on a local network and they can do as they please, whereas with CDMA each device gets a chunk of bandwidth only when they need it.
Some say that CDMA is a superior technology for the following reasons: It allows for more users across a given frequency because it’s only being used when needed, and because battery life on CDMA phones is far superior to that of any GSM device because it’s not transmitting anything when sitting by idle.
However, GSM’s constant contact means that acquiring a signal isn’t as tricky. When a CDMA phone connects to the network, it must negotiate with the local tower what phone it is, what service, what number, etc. This is that pause between when you hit “send” and it starts ringing. The more interference there is, the longer this takes. With GSM, that’s taken care of when you roam into a tower’s area, the phone is “registered” with the tower already and starts transmitting much faster. Also, the already-connected state means that GSM can work in areas (such as elevators, underground) where CDMA generally can not.
The only downside to CDMA at this point in time is it’s lack of mobility across continents. GSM networks are used in more countries (roughly 3/4 of the world market) than CDMA so roaming is hardly ever an issue thanks to that SIM card.
In terms of data transmission, GSM has the upper hand with HSDPA as it is capable of transferring up to 7.2 Mbps while EV-DO Rev.
SOME FACTS -
* CDMA was created by Qualcomm, which holds most of the patents in it. As it is mainly controlled by one company, the cost of maintaining a CDMA network is quite high as compared to GSM, which is an open standard.
* Most of the chipsets in CDMA phones are also made by qualcomm, so there is lesser innovation as compared to GSM phones, which are made by a bunch of companies.
* CDMA based phones are tied to the carrier, and there is nothing like 'SIM' card in it
* The newer versions of GSM (WCDMA, etc.) are getting mainstream, which is breaking CDMA's advantage of a better protocol (faster data transfer speeds).
GSM uses a SIM (Subscriber Identity Module) card while a CDMA SIM card called the R-UIM (Re-Useable Identification Module).
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GSM Vs CDMA
-Sorts messages into time slots in order to send them.
-Voice and data are converted to digital signals that are sent and received in bursts in specific time slots.
CDMA - Code Division Multiple Access
-Was developed by Qualcomm for military anti jamming systems, which translates into highly private conversations.
-It spreads a low power signal across a wide frequency width, which provides for a significant increase in subscriber capacity.
GSM - Global System for Mobile Communications
-Was originally developed in Europe and works similarly to the TDMA system: it sorts messages into time slots.
-The unique feature of this technology is that it allows for a short message service, up to 124 characters, while simultaneously carrying voice traffic.
The GSM Association is an international organization founded in 1987, dedicated to providing, developing, and overseeing the worldwide wireless standard of GSM.
Comaprison - -
To be exact, GSM stands for Global System for Mobile Communications, which is based on an older standard called TDMA.CDMA stands for Code Division Multiple Access. GSM allocates a bit of bandwidth for each user on a local network and they can do as they please, whereas with CDMA each device gets a chunk of bandwidth only when they need it.
Some say that CDMA is a superior technology for the following reasons: It allows for more users across a given frequency because it’s only being used when needed, and because battery life on CDMA phones is far superior to that of any GSM device because it’s not transmitting anything when sitting by idle.
However, GSM’s constant contact means that acquiring a signal isn’t as tricky. When a CDMA phone connects to the network, it must negotiate with the local tower what phone it is, what service, what number, etc. This is that pause between when you hit “send” and it starts ringing. The more interference there is, the longer this takes. With GSM, that’s taken care of when you roam into a tower’s area, the phone is “registered” with the tower already and starts transmitting much faster. Also, the already-connected state means that GSM can work in areas (such as elevators, underground) where CDMA generally can not.
The only downside to CDMA at this point in time is it’s lack of mobility across continents. GSM networks are used in more countries (roughly 3/4 of the world market) than CDMA so roaming is hardly ever an issue thanks to that SIM card.
In terms of data transmission, GSM has the upper hand with HSDPA as it is capable of transferring up to 7.2 Mbps while EV-DO Rev.
SOME FACTS -
* CDMA was created by Qualcomm, which holds most of the patents in it. As it is mainly controlled by one company, the cost of maintaining a CDMA network is quite high as compared to GSM, which is an open standard.
* Most of the chipsets in CDMA phones are also made by qualcomm, so there is lesser innovation as compared to GSM phones, which are made by a bunch of companies.
* CDMA based phones are tied to the carrier, and there is nothing like 'SIM' card in it
* The newer versions of GSM (WCDMA, etc.) are getting mainstream, which is breaking CDMA's advantage of a better protocol (faster data transfer speeds).
GSM uses a SIM (Subscriber Identity Module) card while a CDMA SIM card called the R-UIM (Re-Useable Identification Module).
Read More
GSM Vs CDMA
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