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Technology: CDMA and its possibilities
Technology has always played a dominating role in the mobile phone industry. New techniques and innovations are often introduced to cater to the needs of the huge market, providing better quality as well as convenience.
The Code Division Multiple Access (CDMA) is the latest fad. It has actually turned into a revolutionary technology as it offers several great features.
In Pakistan, the cellphone industry is forecast to emerge as one of the fastest growing markets ever. CDMA seeks to provide services similar to the cellphone operators but by using a different methodology. It is therefore highly probable that it will be the engine of growth for the entire telecom sector.
The growth will in no small part be driven by the ever-intensifying competition. The cost of handsets is also likely to fall, which will further contribute to the growth of the sector. Additionally, there will be many options available to the consumers, with five GSM operators, one CDMA operator (Pakcom is planning to switch to CDMA technology) and numerous WLL operators.
Pakcom operates in Pakistan under the brand name “Instaphone”. The product portfolio of the company comprises a wide spectrum of plans appropriated to different market segments.
CDMA is a special type of digital modulation called “Spread Spectrum”. This form of modulation takes the user’s stream of bits and splatters them across a very wide channel in a pseudo-random fashion. The “pseudo” part is very important here, since the receiver must be able to undo the randomization in order to collect the bits together in a coherent order.
CDMA is a wireless standard that uses spread-spectrum technology to transmit cellular voice and data. This system works three ways. First, any single receiver needs to know the frequencies used by the system and a specific code to decode the data intended for them.
Secondly, by spreading the signal over a spectrum of frequencies, CDMA made the signal very difficult to jam. Thirdly and most importantly, the signal on each frequency can be made to sound like background noise, making the transmissions difficult to identify and therefore recognize as a transmission to actively tap or jam.
One of the phrases associated with CDMA is “Soft Handoff”. A “handoff” occurs in any cellular system when your call switches from one cell site to another as you travel. In all other technologies this handoff occurs when the network informs your phone of the new channel to which it must switch. The phone then stops receiving and transmitting on the old channel and it commences transmitting and receiving from the new channel.
As TDMA began to enter the cell market, the need to squeeze more users into cell bandwidth around the country and the world created enough demand for an improved technology. CDMA differs from TDMA through use of “spread-spectrum” technology. The bandwidth is the unique selling proposition for CDMA technology.
CDMA technology offers numerous advantages to users. Since it is a digital system, it has less exposure to minor interference, improving voice quality and eliminating the audible effects of multipath fading. Furthermore, CDMA technologies use the same spectrum for each base station, differing only by the particular code of the system.
This means that a single handset can actually communicate with two towers at the same time and without any frequency change, allowing a seamless transfer and few to zero dead-zones.
The capacity is also increased, allowing more users at any given time and more user-minutes over the long run. One of the final user-end advantages of CDMA is the ability of a single handset to decode multiple user-channels, allowing bandwidth to scale.
This technology also offers numerous advantages to service providers. One of the most applicable features to business situations is a unique flexibility of cell service. CDMA technology allows a service provider to shift priorities between coverage, quality, and capacity. By reducing voice quality (lower data rate dedicated to voice), the provider can increase coverage or capacity. As a result of power flexibility (which will be discussed in a moment), capacity can be improved by reducing coverage, etc. This flexibility allows providers to further customize their services depending on the needs of their particular customers.
Another feature of CDMA technology involves transmission power and is responsible for a number of its advantages. While the actual physics of the system is complicated, the result of the technology is that the system is capable of transmitting at different power levels.
This means that a single part of the system will “hear” all the signals near the same power level, making each individual encoded signal easier to identify and less exposed to crosstalk. The benefits of this are vast, including greater network capacity, consolidation of multiple cells to single towers and greater coverage.
Thus, consolidation of multiple cells to signal towers have had considerable cost savings as opposed to GSM and TDMA networks. Service providers recognize the greatest advantage in cell power flexibility when they have to deal with cell tower locations. Rather then build a tower for each cell, directional transmitters can consolidate three cells onto the same tower, reducing the costs of setting up, upgrading, and maintaining networks.
By providing better facility and quality, one can easily analyse the wonderful features of this cellular technology, rather superior technology. CDMA proves to be more efficient as it provides more facilities to the user.
The writer is a freelance contributor
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