Difference Between CDMA and WCDMA (with Table)

Intercommunication devices have turned out to be of the utmost use in this 21st Century. Earlier, we used to have mobile phones, pagers, radios, etc. Nowadays, thanks to the internet, most of our devices are connected through it. Whether it is our computers, our TVs, our mobile phones, anything. However, we ought to look into the more fundamental aspects of these kinds of communication networks. How do they function and why? This is where CDMA and WCDMA come into play. 

CDMA stands for Code Division Multiple Access. This is basically an algorithm that helps a user capture a number of channels to be used in the same bandwidth. So, in simple terms, it makes connection better by accommodating more users per MHz of bandwidth.

WCDMA stands for Wideband Code Division Multiple Access. It basically uses the same technology as that of CDMA but incorporates it into 3G. This works with GSM and EDGE to be used as UMTS and also resulted in higher internet speed.

The difference between CDMA and WCDMA is that CDMA is the technology used in 2G networks, while WCDMA is the technology used in 3G networks.

Comparison Table between CDMA and WCDMA

Parameters of ComparisonCDMAWCDMA
DefinitionCDMA is an algorithm that brings in more channels in a specified bandwidth.WCDMA uses the basic technology of CDMA but incorporates it into GSM and EDGE.
NetworkUsed in 2G network.Used in 3G network.
SpeedRelatively slower than WCDMA.Faster than CDMA.
GSMIs a rival to GSM.Works with GSM.
Bandwidth1.25 MHz.5 MHz.

What is CDMA?

CDMA stands for Code Division Multiple Access. This is basically an algorithm that helps a user capture a number of channels to be used in the same bandwidth. So, in simple terms, it makes connection better by accommodating more users per MHz of bandwidth. So, in a way, CDMA multiplexes various signals to be fit into a single given bandwidth. Usually, CDMA operates in the ultra-high-frequency region, which is mostly between 800 MHz to 2 GHz.

However, one should not confuse the mode of operation of CDMA with the usual methods of time and frequency multiplexing. This is because, in CDMA, a customer is able to access the network for the whole duration, without any supposed interruptions. The main reason for this is because this algorithm gives each user a unique identity, which helps to identify any two different customers.

The working of CDMA is an intricate mechanism, that allows up to 61 users at the same time, and fits them all into the same 1.23 MHz. There are 64 Walsh codes. These codes help the algorithm to differentiate between the theoretical limits and the calls. However, in real-time applications, due to technical limitations and quality purposes, the real number is usually lesser than this number.

Using CDMA has its own advantages and disadvantages. The main advantages of using CDMA include low interference due to transmission bursts, usage of rake receivers to improve receivers. Usage of flexible transfer, which helps the switching of mobile stations without changing the operator.

The main disadvantages of CDMA include delay due to the large size of code, requirement of a precise, time synchronization, also gradual transfer often saturates radio capacity.

code division multiple access cdma

What is WCDMA?

WCDMA stands for Wideband Code Division Multiple Access. It basically uses the same technology as that of CDMA but incorporates it into 3G. This works with GSM and EDGE to be used as UMTS and also resulted in higher internet speed. WCDMA signifies the leap from 2G to 3G and thus is miles ahead in terms of speed. This is due to a very specific reason. CDMA is a competitor of GSM and hence, they did not incorporate technologies to build something faster and stronger. However, WCDMA incorporates GSM and EDGE, which finally led to UMTS. This resulted in better connectivity, better capacity, and better speed.

WCDMA supports a wide range of technological connectivity, such as cellular voice, text, MMS, and 3G.

WCDMA deploys a Direct Sequence Code Division Method (DS-CDMA) channel access method, a frequency division duplexing. These help it to attain better connectivities and higher speeds.

WCDMA has two modes:

  1. Frequency Division Duplex (FDD) – This is a method of separating users by software and hardware. They use the code as well as the frequencies to differentiate between the users. Two frequencies are used. One of them is uplink and the other is the downlink.
  2. Time Division Duplex (TDD) –  In this method, in addition to the frequencies and code used in FDD, time is another factor that is used to differentiate between the users. 

Advantages of WCDMA include higher connection speeds and stronger networks. The main disadvantages of WCDMA are that it is not used worldwide, so there is a compatibility issue for a lot of handsets.

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Main Differences Between CDMA and WCDMA

  1. The main difference between CDMA and WCDMA is that CDMA is an algorithm that beings more channels in a single bandwidth, while WCDMA uses CDMA and incorporates GSM and EDGE in it.
  2. CDMA is used over a 2G network, while WCDMA is used over a 3G network.
  3. CDMA is slow compared to WCDMA.
  4. CDMA rivals with GSM, while WCDMA works with it.
  5. CDMA operates in a bandwidth of 1.25 MHz while WCDMA operates in 5 MHz.

Conclusion

In this modern-day and age, where connections are more important than ever, it is now necessary to stay connected. We need connections that are strong, reliable, and fast. Technology, be it software, or hardware keeps evolving at rapid rates so as to facilitate us with these benefits.

Both, CDMA and WCDMA are a result of this, and this is not the last step in the human history of efficient communication. There will be more to come, with speeds that will blow away the human mind!

References

  1. https://dl.acm.org/doi/abs/10.5555/525067
  2. https://books.google.com/books?hl=en&lr=&id=DRO6CwAAQBAJ&oi=fnd&pg=PR5&dq=wcdma&ots=R6XtqSHTYf&sig=8RZQ4jYDxYKA88mQTz6kIom1pa0