EXTENSIVE POTENTIAL FOR CDMA IN AZERBAIJAN
The number of mobile communication network users is growing faster than the architect of this technology had imagined. By 2006 end, the number of subscribers is estimated to reach around 1.7 billion and cover 26% of the world’s population. CDMA (Code Division Multiple Access) technology has turned out to into a very promising communications system within the world market. Decades ago, this technology was used by the U.S military and is presently recognized as a global digital standard for commercial communications.
In recent years, CDMA technology has been tested, standardized, licensed and put into production by majority of wireless equipment suppliers and is already being widely used all over the world. This technology is especially popular in countries with rapidly developing economies such as India and China.
Over 50% of total CDMA users are in the Asian region. CDMA technology covers 47% of the American communications market.
The Azerbaijan-American joint venture Catel (Caspian American Telecommunications, LLC) is presently dealing with introducing this little-known technology in Azerbaijan. Sadykh Gumbatov, the Executive Director of the joint venture shares his thoughts on this new technology, its potential and activities of the company.
Caspian Energy (C.E.): Mr. Gumbatov, what is CDMA and what is its potential for the Azerbaijan market?
Sadykh Gumbatov: The world is becoming more mobile and information-oriented. New technologies change our lifestyle, form our habits and influence our worldview. The 3G mobile communication is another step towards formation of information space common to all countries and continents and one more step towards freedom.
Unlike other methods that provide subscribers with access to the network where the signal drive is concentrated on a chosen frequency or temporary intervals, CDMA signals are distributed within a continuous time-and-frequency space. In fact, this method operates frequency, time and power. What is the advantage of CDMA over other digital technologies? CDMA technology provides high quality speech simultaneously reducing output and noise level. The result is continuous high quality voice and data transmission with minimal average output power.
Unlike other standards applied nowadays, a hundred-fold decrease in power output is the distinguishing feature of CDMA technology from the point of view of two important factors: influence on the human body and duration of work without battery recharge. CDMA capacity is 10-20 times higher compared to other similar systems, and 3-6 times higher compared to capacity of other digital systems.
Networks based on this technology effectively use radio-frequency signals because of re-using the same frequencies within the network.
The group of CDMA standards fundamentally differs from other standards within cellular telephony and they are justly regarded as 2.5G standards. FDMA (NMT, AMPS, NAMPS) and its extension TDMA (GSM, DAMPS) use sets of frequency range by dividing each channel into time intervals (for TDMA) to provide subscribers with access to cellular network services. As for CDMA, it operates in another way.
CDMA uses the Direct Sequence (Pseudo Noise) Spread Spectrum technology. DSSS uses pseudonoise signal and wider than necessary bandwidth for ordinary modulation devices.
This technology provides users with the following opportunities:
• Good quality voice transmission. Lower power consumption.
• Small percentage of interrupted talks.
• Expanded coverage.
• Safety and confidentiality of information.
• Additional services.
The CDMA system has a wide outlook in Azerbaijan. All over the world, the number of CDMA technology users is growing more rapidly compared to other systems. We expect such a result in Azerbaijan too. To date, the number of Catel subscribers exceeds 20,000 and displays a tendency of growth. The present-day technical base of the enterprise allows rendering the service to over 80 thousand clients; the network can be expanded at any given time if necessary.
C.E.: What coverage does Catel have now? What projects will be implemented in the near future?
Sadykh Gumbatov: Presently, the CATEL covers the Absheron Peninsula, Baku, Sumgait, Ganja, Shamkir and Nabran. Catel keeps on working in this direction and intends to cover the whole territory of our country in the near future. We plan to invest around 20 million USD in 2006. The Company is going to start up various technological innovations. For instance, at present SMS service is available for the subscribers of the Catel network.
C.E.: What are advantages of CDMA technology compared to standards well-known to the Azerbaijan customers?
Sadykh Gumbatov: CDMA technology has a number of significant advantages compared to other working standards. They are: more effective RF use, wide exchange capacity and operating distance, better protection ration and quality of communication, high protection from illegal access and listening. The CDMA network capacity is eight times higher than AMPS. Comparison between this technology and GSM shows that the number of base stations used by CDMA to cover the same territory is 3-times lower.
Communication quality is the primary criteria in the process of choosing a new digital standard. CDMA provides better quality transmission. Therefore, impressing results were achieved due to use of high-quality voice coding algorithms and the so-called "soft shift".
Within ordinary cellular networks, communication quality gets worse when a cellular subscriber shifts from one network cell to another. In this case the so-called "hard shift" takes place, as, in order to shift cells the communication must be at first broken and then reestablished with a new cell. CDMA uses "soft shift" when a mobile phone first establishes communication with the base station to enter its coverage. Only then does it leave the channel in the cell. Frequent hard shifts make communication quality much worse and can even cause interruption. "Soft" shift avoids such problems.
The HS data transmission capacity within the CDMA networks was began way back to this standard’s development manage. Data transmission speed within CDMA networks is better compared to similar indicators for GSM (GPRS).
It would be worth to note that even after modernization of GSM to GPRS, data transmission will use the resources of GPRS voice communication, thus influencing quality of communication.
As for CDMA technology, it offers more effective use of the existing range and even gives an opportunity to speak to and transmit data at the same time. CDMA subscribers are really provided with a range of opportunities. When you speak confidentially or transfer data you want to secure yourselves against listening from the side of the third party. Considering the fact that CDMA technology was originally worked out to be used in the US Army, it is obvious that the primary attention was focused on matters related to reliability of the system operation and protection of transmitted data. Thus CDMA technology guarantees confidentiality of your talks.
CDMA is Multichannel Access with the Code Division of Channels. Unlike other radio communication technologies where the existing frequency spectrum is divided into narrow-band channels and time intervals, the CDMA system distributes signals within the wide band. Thus, the CDMA system provides more effective use of the existing frequency spectrum and significantly expands its total capacity.
C.E.: What is the total capacity of the CDMA system?
Sadykh Gumbatov: The total capacity of the CDMA system is 10-20 times higher compared to similar AMPS systems and at least three times higher compared to other technologies of the digital communications such as TDMA and GSM. Within the existing cellular system the total capacity can be expanded only stepwise. The overall throughput capacity of the system can be doubled if to shift only 10% of the spectrum from the AMPS technology to CDMA. Due to the throughput capacity, the CDMA system prevents call-blocking, gives opportunity to meeting the growing demand on service and supports new kinds of digital services such as identification of a calling subscriber, data transmission and mobile facsimile.
The uniqueness for each separate linking coding scheme within the CDMA system almost removes crosstalk noise and considerably reduces influence of noises from other sources. This approach also removes the necessity to shift the carrier frequency between neighbouring cells thus providing subscribers with reliable ‘soft’ message forwarding, which prevents interruption of a call. Use of the integral receivers of Rake type, the Qualcomm system, significantly reduces a multipath effect occurring nearby multistoried buildings and cross-country areas.
Thanks to the capacity management technology protected by patents, the system also reduces signal attenuation close to the borders of cells. Use of variable-speed data transmission 13 kb/c vocoders within the CDMA system provides voice transmission quality comparable to the communication quality of landlines.
The typical output power of the CDMA portable is only 2 mw, which is much lower compared to the average output power of GSM devices at 125 mw. Due to reduction of consumed power, the portable devices of CDMA considerably increase duration of online work (up to 5 hours) and standby (up to two days). Reduction of energy consumption allowed reducing size and weight of cellular phones as well as charging time.
C.E.: What can you tell about ecological and medical safety of the CDMA system?
Sadykh Gumbatov: the CDMA technology meets all ecological standards when compared to presently used cellular communication technologies.
Reduction of output power, as I mentioned before, decreases risk for health and reduces interference with other radio communication devices. The signals with expanded spectrum applied within the CDMA system provide a wider coverage compared to signals used within AMPS, TDMA or GSP systems. As a result, the number of base stations necessary for CDMA systems is 2-5 times lower, which is also a good indicator proving the ecological effectiveness of the system.
Within ordinary networks, phones use more power than necessary for stable linkage with a base station for not loosing communication because of noises. Compared to GSM, the CDMA wideband signal is less subjected to interferences. The purity of voice transmission and stable connection are reached by means of transmitting power management depending upon conditions of signal distribution. That is why a CDMA mobile phone uses minimal capacity necessary for communication maintenance, thus improving ecological parameters of the phone and reducing their influence on the human body to a minimum.