CDMA VS. GSM.
CDMA stands for “Code Division Multiple Access.” GSM stands for “Global System for Mobiles.” They are 2 radio networks used by wireless carriers.
If the GSM/CDMA divide has popped up on your radar, it’s likely because you tried to transfer a phone from one carrier’s service to another and encountered roadblocks. Many that were designed to operate on one type of network are incompatible with the other. Depending on the specific phone and the carrier, you might have found that you were ineligible to transfer a device you owned to a new carrier’s network
Both CDMA and GSM are multiple-access technologies, meaning they allow multiple calls or data connections on one radio channel. GSM transforms calls into digital data, gives them a shared channel and a time slot and puts the pieces of each call back together for the listener on the other end. CDMA encodes each call’s data with a unique key. Then all calls are transmitted at once, with receivers “dividing” the combined signal back into individual calls.
Of the two, GSM is more widely used around the globe, with availability in more than 200 countries. While CDMA is used widely in the U.S., it is less common elsewhere — most estimates pin the portion of global wireless networks using CDMA at less than 20 percent. The Verizon network is a CDMA wireless network.
When it comes to smart devices and service options, it’s important to understand 2 bands: CDMA vs. GSM.
No, they’re not the names of up-and-coming techno groups. GSM and CDMA are frequency bands that support cellular service. While these letter jumbles may be unfamiliar, they can have a significant effect on phone carrier choice and can also affect phone type.
With next-level networks being built, your current device might limit you depending on its model. Here’s what you need to know about CDMA vs. GSM, how the distinction might affect your phone and what to look for in the future.
FEATURES OF CDMA NETWORK
- Many users of a CDMA system share the same frequency. Either TDD or FDD may be used.
- Unlike TDMA or FDMA, CDMA has a soft capacity limit. Increasing the number of users in a CDMA system raises the noise floor in a linear manner. Thus there is no absolute limit on the number of users in CDMA but the system performance gradually degrades for all users as the number of users is increased.
- CDMA is a interference limited system.
- Multipath fading is substantially reduced because the signal is spread over a large spectrum. If the spread spectrum bandwidth is greater than the coherence bandwidth of the channel, the inherent diversity will reduce the effect of small scale fading.
- Channel data rates are very high in CDMA systems. The symbol duration is very short and usually much less than the channel delays spread. A RAKE receiver can be used to improve reception by collecting time delayed versions of the required signal.
- CDMA uses co-channel cells thus it can use macroscopic spatial diversity to provide soft handoff.
- Self-jamming is a problem in CDMA system. Self-jamming arises from the fact that the spreading sequences of different users are not exactly orthogonal.
- The near-far problem occurs at a CDMA receiver if an undesired user has a high detected power as compared to the desired powers
What carriers use CDMA network?
In the US, Verizon, US Cellular, and the old Sprint network (now owned by T-Mobile) use CDMA. AT&T and T-Mobile use GSM. Most of the rest of the world uses GSM. The global spread of GSM came about because in 1987, Europe mandated the technology by law, and because GSM comes from an industry consortium.
What is the difference between CDMA and GSM networks?
CDMA stands for Code Division Multiple Access. … One of the biggest differences between these two systems is that GSM phones use SIM cards to link a particular phone with its network, while CDMA phones don’t require a SIM card because the phone itself is linked to the network
Which is better GSM or CDMA?
GSM users can experience better voice quality than CDMA users or vice versa in particular areas. … On the other hand, not all CDMA phones can transmit voice and data at the same time. In addition to the network congestion, CDMA call quality tends to be better than GSM.
Advantages of CDMA
- One of the main advantages of CDMA is that dropouts occur only when the phone is at least twice as far from the base station. Thus, it is used in the rural areas where GSM cannot cover.
- Another advantage is its capacity; it has a very high spectral capacity that it can accommodate more users per MHz of bandwidth.
Disadvantages of CDMA
- Channel pollution, where signals from too many cell sites are present in the subscriber. s phone but none of them is dominant. When this situation arises, the quality of the audio degrades.
- When compared to GSM is the lack of international roaming capabilities.
- The ability to upgrade or change to another handset is not easy with this technology because the network service information for the phone is put in the actual phone unlike GSM which uses SIM card for this.
- Limited variety of the handset, because at present the major mobile companies use GSM technology.
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