Difference Between WCDMA and HSDPA

Edited by Diffzy | Updated on: April 30, 2023


Difference Between WCDMA and HSDPA

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Even though you may or might not be acquainted with these phrases at the present. These are technologies that let consumers connect to the internet at significantly accelerated rates. The evolution of WCDMA and HSDPA, in addition to the key distinctions between the two technologies, will be covered in this section. To ensure that you have a comprehensive grasp of the topic at hand, many technical jargons will be explained using language that is easy to comprehend throughout the articles.

WCDMA is an acronym that stands for Wideband Code Division Multiple Access. It is a mobile technology that enhances the capabilities of the existing GSM networks that are now being used all over the globe. This technology is generally referred to as 3G, which stands for "third generation." It enables users to access more recent services, such as video calling in addition to the classic call, as well as text messaging capabilities that are currently commonplace. Since HSDPA (High-Speed Downlink Packet Access) does not provide a significant boost to the feature set of WCDMA, it is more frequently referred to as 3.5G. This is because HSDPA enhances the speed of data transfer, which in turn improves the quality of the services.

WCDMA networks could only achieve maximum speeds of 384 kbps before the advent of HSDPA technology. Even while this could be enough for the majority of services, individuals will almost always demand higher speeds, particularly when they are surfing the internet or downloading files. HSDPA enabled download rates greater than 384 kbps, the most noteworthy of which being 3.6 Mbps and 7.2 Mbps, both of which are often advertised by several different telecommunications operators. The amount of speed that may be achieved with HSDPA is dependent on the particular sort of modulation that is being used. Theoretically, the greatest speed that may be achieved using HSDPA is 84 Mbps.


The main difference between WCDMA and HSDPA is that the former supports a slower data transfer rate. On the other side, High-Speed Downlink Packet Access (HSDPA) makes comparatively greater speed possible. The technology known as WCDMA came before the technology known as HSDPA. WCDMA may also be referred to by its expanded name, Wideband Code Division Multiple Access. The extended version of HSDPA is referred to as High-Speed Downlink Packet Access.

The logical node B and user equipment, such as a phone, communicate with one another through WCDMA technology, which acts as an air interface between the two (for instance the mobile tower). This is a cutting-edge technology that stands in stark contrast to the methods and tools that were available in the past. It is capable of providing cellular connectivity of the third generation, often known as 3G. As a consequence of this, we can engage in video chatting, but this technology is still evolving, as will be seen in the next section of this article.

Since HSDPA (High-Speed Downlink Packet Access) does not provide a significant boost to the feature set of WCDMA, it is more frequently referred to as 3.5G. This is because HSDPA enhances the speed of data transfer, which in turn improves the quality of the services. WCDMA networks could only achieve maximum speeds of 384 kbps before the advent of HSDPA technology.

WCDMA is a third-generation (3G) standard that utilizes the direct-sequence code division multiple access (DS-CDMA) channel access method as well as the frequency-division duplexing (FDD) method to provide high-speed and high-capacity service. Wideband Code Division Multiple Access (WCDMA) is an abbreviation for Wideband Code Division Multiple Access. The version of the Universal Mobile Telecommunications System that is used the most often is known as WCDMA (UMTS). It was created by the Japanese company NTT DoCoMo, and it served as the foundation for the company's Freedom of Multimedia Access (FOMA) 3G Network.

You could have picked up on a phrase called "downlink" in HSDPA after seeing it in the expanded form. The importance of this concept may be attributed to the fact that this technology makes it possible to achieve a speed boost of 14 megabits per second. The downlink refers to the direction in which the wave travels when it is formed between the user equipment and the tower. Although the theory centers on 14 Mbps, the data may shift in the actual world due to several factors.

Difference Between WCDMA and HSDPA in Tabular Form

Parameters of Comparison WCDMA HSDPA
Is it the first UMTS version? Yes No
Speed of downlink Up to 384 kbps. (per user) As much as 14.4 Mbps (per user)
Does it have a similar downlink and uplink range? Yes No
Year of deployment 2001 Mid 2005
Which is faster?  The other is far faster than this one. It is without a doubt the one with the fastest speed.

What is WCDMA ?

The beginning of the high-speed cellular revolution may be traced back to the invention of WCDMA, which was the first technology to be developed under the UMTS umbrella (Universal Mobile Telecommunications System). 2001 was the year that saw the introduction of the technology. NTT Docomo was the first company to build a WCDMA 3g network, and they did so in October of 2001. The high speed is achieved by the use of the direct sequence Code Division Multiple Access channel access technology as well as Frequency Division Duplexing. As a direct consequence of this, it was developed concurrently with the 3G collaboration program. This initiative, in turn, comprises the development of core cellular networks that are part of the GSM, which stands for the Global System for Mobiles.

Both FDD and TDD are supported by the wireless communications technology known as WCDMA. To differentiate one user from another, FDD relies on a system of codes and frequencies, as we have just gone over in the previous section. Uplinks and downlinks are the two categories of frequencies that may be used. TDD, which stands for "time division duplex," is a method that isolates users using code and frequency in addition to the time factor. In this particular instance, the uplink and the downlink make use of the same frequency. In addition, the CDMA technology is used for the air interface, and the term "wide length" refers to the expanded capacity of connection that the technology offers at 5 MHz. It is also important to keep in mind that the TDD mode of WCDMA is a combination of CDMA and TDMA.

CDMA, or code division multiple access, is used for the air interface of WCDMA, even though WCDMA is meant to function on developed GSM core networks. Code division multiple access (CDMA) is used by the vast majority of 3G systems now in operation, while time division multiple access is used by the remaining systems (TDMA). In practice, the TDD mode of WCDMA makes use of a hybrid transmission scheme that combines TDMA and CDMA.

Both TDMA and CDMA enable users to share the same channel, but TDMA does so by slicing the channel up into discrete time slots rather than simultaneously sharing it with many users. CDMA provides advantages such as multipath diversity and smooth handoffs between channels.

WCDMA is a technology that may be used as an air interface, and it can artificially enhance the bandwidth of transmission. To accomplish this goal, it modulates each baseband signal with a binary or quaternary signature at a rate that is much greater than that of the original data symbol.

What is HSDPA?

As is common knowledge, "High-Speed Downlink Packet Access" (HSDPA) is the abbreviation for "HSDPA." So, what exactly is it, and how does it compare to the previous method in terms of speed? A downlink speed of 14 Megabits per second is achievable thanks to the technology. This is considered to be a speed that is considered to be fast. This technology has several benefits, one of which is that it focuses more on the downlink, making it possible to deploy the downlink more quickly. It should be noted that the peak data rate of the uplink has not altered in contrast to the downlink; rather, it has remained the same as it was for both the uplink and the downlink of the prior, which was 384 kbps. In addition, the technology was developed with the purpose of only handling packet data. As a direct consequence of this, phone and data services delivered by circuit switches remain unaffected. In its most basic form, it is a radio access system. Even in situations when significant adjustments are made to the radio interface, the effect on the core network is usually not much altered.

Aside from that, HSDPA was designed to signify asymmetric data services. In these types of services, the majority of the data transmission takes place in the downlink, while the uplink only handles a tiny percentage of the total. Since HSDPA uses the same band length as release 99 (UTMS), which is 5MHz, it is categorized as a release 5 system in the UTMS mapping process. This is because HSDPA uses the same band length. It can accommodate both voice communications and data transmissions in the same bandwidth concurrently. It retains the fundamental network architecture of the R99 version and does not contain any newly developed network components. Aside from that, it is fully compatible with Release 99 in every other way.

Main Differences Between WCDMA and HSDPA in Points

  • The earliest version of UMTS was called WCDMA, and the HSDPA standard was established after the WCDMA standard.
  • WCDMA offers download speeds of 384 kbps, while HSDPA offers download speeds of 14 Mbps (downlink).
  • WCDMA does not have latency periods that are lower than those of HSDPA.
  • WCDMA does not have packet scheduling that is nearly as quick as HSDPA.
  • WCDMA (3G) connections are slower than HSDPA ones (3.5G).
  • According to the TTI, Transport Block Size, modulation techniques, and other factors utilized for HSDPA networks, HSDPA handsets are classified into a total of 12 categories, but WDMA networks were not classified in this manner in the initial 3G network deployment.
  • HSDPA networks make use of a feature known as Fast HARQ (Hybrid Automatic Repeat Request), whereas regular WCDMA networks do not make use of this capability.


The transition toward high-speed cellular communication was kicked off with the development of WCDMA, the first technology to operate under the UMTS standard (Universal Mobile Telecommunications System). The direct sequence Code Division Multiple Access channel access mechanism and frequency division duplexing are applied to accomplish the high speed that is required. As we have seen, FDD functions by using codes and frequencies to differentiate one user from another. This is how it can recognize one user from another. The addition of time into the equation of code and frequency isolation is what time division duplex, more commonly known as TDD, does.

As is well knowledge, the abbreviation HSDPA refers to High-Speed Downlink Packet Access. This technique allows for a downlink speed of up to 14 Megabits per second to be achieved. Another advantage of this technology is that it places a greater emphasis on the downlink, which speeds up the process of deploying the downlink. The peak data rate of the uplink is the same as that of the downlink; in fact, it is the same as the peak data rate of the uplink and downlink that came before it, which was 384 kbps. In addition, the technology was developed with the intention of handling packet data. Aside from that, HSDPA is intended to denote asymmetric data services, in which the downlink is responsible for the bulk of the data transmission and the uplink is responsible for just a tiny fraction of the data transmission.

Hence, the evolution includes 2G network, followed by WCDMA which is linked with 3G and then, it is HSDPA which is considered like 3.5G because of its high transmission speed. 


  1. https://ieeexplore.ieee.org/abstract/document/4288758/
  2. https://ieeexplore.ieee.org/abstract/document/4288754/

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"Difference Between WCDMA and HSDPA." Diffzy.com, 2024. Mon. 17 Jun. 2024. <https://www.diffzy.com/article/difference-between-wcdma-and-hsdpa-904>.

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