NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote
Prior to actually speaking about the properties of the CDMA 2000 I would like to note that Cdma 2000 is a third generation radio transmission technology that evolved from the cdma One-based system. The cdma 2000 provides a true multimedia system that offers the users improved capacity for both voice and data applications and accessibility to intranet and internet applications at high data rates. It should also be noted that cdma 2000 is certainly a revolutionary technology that is expected to benefit the wireless internet and cell phone technology in the near future. 3 G (third generation) is the term used to describe next generation mobile services which provide better quality voice and high-speed Internet and multimedia services. While there are many interpretations of what 3 G represents, the only definition accepted universally is the one published by the International Telecommunication Union (ITU). ITU, working with industry bodies from around the world, defines and approves technical requirements and standards as well as the use of spectrum for 3 G systems under the IMT- 2000 (International Telecommunication Union- 2000) program. The ITU requires that IMT- 2000 (3 G) networks, among other capabilities, deliver improved system capacity and spectrum efficiency over the 2 G systems and support data services at minimum transmission rates of 144 kbps in mobile (outdoor) and 2 Mbps in fixed (indoor) environments (Knisely, 64).
The CDMA 2000 standard is evolving to continually support new services in a standard 1. 25 MHz carrier. The first phase of CDMA 2000, or CDMA 2000 1 X will deliver average data rates of 144 kbps. Phase two, labeled CDMA 2000 1 x EV, will provide for data rates greater than 2 Mbps (Pittampalli, 10). In simpler terms, cdma 2000 system provides protocols and services that correspond to the bottom two layers of the ISO/OSI reference model - physical layer and link layer (Dahlman, 72). Applications and upper layer protocols corresponding to OSI layers 3 through 7 utilize the service provided by these two lower layers.
To handle higher bandwidths and a wider variety of services, the link layer is enhanced to support a fully generalized multimedia service model that allows virtually any combination of voice, packet data and high-speed circuit data services to be operated simultaneously (Balachandran, 36). The link layer of the cdma 2000, I should note, provides the protocol support and control mechanisms to provide data transport services. It supports varying levels of reliability and Quality of Service (QoS) characteristics according to the needs of the specific upper layer service. And it performs all of the functions that are necessary to map the data transport needs of the upper layers into the specific capabilities and characteristics of the physical layer.
The link layer is further divided into two sub-layer Link Access Control (LAC) and Media Access Control (MAC). One should not forget that the cdma 2000 has evolved from cdma One and therefore it does posses various qualities attributable to cdma One. One important aspect is the backward compatibility or the ability to support an overlay of cdma 2000 and cdma One networks in the same spectrum. Another thing worth mentioning is that the multi-carrier design of the cdma 2000 forward link makes it possible to perform such an overlay (Knisely, 66). The radio frequency bandwidths and data rates supported by cdma 2000, by the way, are much wider than the bandwidths and data rates of other systems. The wide range of data rates supports various applications ranging from pure voice and low-speed data to high-speed packet and circuit data access.
To meet the different QoS requirements for different types of services, two types of data traffic channels are defined and are called Fundamental Channel and Supplemental Channel. One winsome technical aspect is that the cdma 2000 use QPSK Walsh modulation, which doubles the number of Walsh codes available compared to other systems like GPRS or IS- 95 and increases processing gain in the same time. Each physical channel is spread with a Walsh code word to provide orthogonal channelization among different channels and different users. The channels are code-multiplexed with independent gain, which allows the support of multiple services in an efficient manner. The QoS requirements can then be set independently for optimal allocation of reverse link resources (Dahlman, 73). I should also note that for multi-carrier CDMA channel, the user data is de multiplexed onto N carriers, after scrambling with the long code corresponding to user m.
On each carrier, the de multiplexed bits are mapped onto I and Q and followed by Walsh spreading, PN spreading and frequency modulation as in the direct spreading channel. For the common uneducated user this means that cdma 2000 provides for enhanced protection of data so needed in wireless internet or cell phones. For the cdma 2000 company it means that the internal controls are maintained and the users are properly served at a cheap price (Balachandran, 38). The creators of the cdma 2000 in order to improve the performance of the forward link in a low-mobility environment, incorporated in their creation that cdma 2000 represents the fast forward link power control. Similar to the operation of the cdma One reverse link, the mobile station measures the forward link traffic channel power and issues a "power up" or "power down" command back to the base station based on the measurement (Knisely, 69). Performance results indicate that a significant improvement is achieved at low speeds which allows the cdma 2000 users to enjoy high productivity during rush hours when the cdma 2000 channel is overwhelmed or for technical reasons the speed is low.
For high-speed data transfers, which typically occur in low-mobility environments, this improvement in performance is crucial in providing higher forward link capacity, which for most users is reflected in ability to use their wireless internet / phone at a great distance from the cell phone towers (Pittampalli, 15). It is a common knowledge that CDMA 2000 is the 3 rd Generation solution based on the system called IS- 95. Unlike some 3 G standards, It is an evolution of an existing wireless standard. CDMA 2000 supports 3 G (third generation) services as defined by the International Telecommunications Union (ITU) for IMT- 2000. 3 G networks will deliver wireless services with better performance, greater cost-effectiveness and significantly more content (Balachandran, 40). The goal is access to any service, anywhere, anytime from one terminal - true converged, mobile services. CDMA 2000 is one solution for wireless operators who want to take advantage of the new market dynamics created by mobility and the Internet.
CDMA 2000 is both an air interface and a core network solution for delivering the services that customers are demanding today. These services are sometimes referred to as 3 G (Pittampalli, 17). CDMA 2000 and 3 G are synonymous. CDMA 2000 is designed to mitigate risks, protect investments and deliver significant performance boosts to operators as they evolve their networks to offer 3 G services. CDMA 2000 networks are backward compatible to cdma One deployments, protecting operator investments in cdma One networks and providing simple and cost-effective migration paths to the next generation. In addition, CDMA 2000 networks offer voice quality and voice capacity improvements, and support for high speed and multimedia data services (Dahlman, 75).
Speaking about the benefits the new system provides because of its multiservice aspects, one should remember the following. Cdma 2000 uses the backward compatibility with cdma One which allows the users to cheaply migrate to the 3 rd generation system. The voice quality and capacity is certainly improved for the fact that cdma 2000 offers at least twice the same capacity of the cdma One. The wireless internet data can be transmitted at a rate from 144 kbps to 2 Mbps with hardly any interruptions. The cdma 2000 multiservice allows for simultaneous voice / data support of multimedia applications that gain more and more popularity not only with the internet but also with the mobile phones.
Cdma 2000 as a customer lure offers extended battery life, smart antennas (follow-me-service) and the hot spot coverage (aka spot beams). In conclusion I would like to note that as capacity and data rate capabilities of wireless networks continue to be challenged, a number of enabling technologies have emerged, which provide performance enhancements. The cdma 2000 standard is a wide-band, spread spectrum radio interface that uses CDMA technology to provide one available solution for the third generation of wireless communication systems. The cdma 2000 provides a true multimedia system that offers improved capacity for both voice and data applications and accessibility to Intranet and Internet applications at high data rates. It meets or exceeds all the IMT- 2000 requirements, and provides a smooth migration path from second to third generation systems.
While maintaining backward compatibility with existing IS- 95 CDMA system, large enhancements of cdma 2000 are achieved in many aspects: wide-band, supplemental channel, pilot-based coherent detection, fast forward power control, forward link transmit diversity, auxiliary pilot channel and Turbo codes. Compared to the GPRS- 136, the cdma 2000 is more competitive and attractive with respect to the peak data rate, methods for higher data rate and other issues. While both the cdma 2000 and UMTS/W-CDMA are the third-generation CDMA standard, just acting as North American version, Europe and Japan version respectively. They are similar and differ in many ways. Harmonization for a Global Third Generation (G 3 G) CDMA approach is being done by major international operators and manufacturers. The development of the cdma 2000 is based on the experience of operators and equipment manufacturers in the development and deployment of second-generation cdma One networks.
Due to the large investment in infrastructure deployment in cdma One networks worldwide, the ability to protect this investment and, at the same time, to evolve the network to support additional capacity and service enhancement provides a practical solution to the new generation. This will make third-generation radio transmission networks a reality in the near future. Reference: H. Home and A. Toskala (eds), WCDMA for UMTS: Radio access for Third generation Mobile Communication, Wiley, 2000. Chapter 13 S.
Willeneger, cdma 2000 Physical Layer: An Overview. Journal of Communication and Networks, Vol 2, No 1, pp 5 17, March 2000. S. Dennett, "The cdma 2000 ITU-R RTT Candidate Submission, " V. 0. 17, TIA, June 02, 1998, p 6 - 22 Douglas N. Knisely, Quinn Li, and Nallepilli S.
Ramesh, "cdma 2000: A Third-Generation Radio Transmission Technology", Bell Labs Technical Journal, July - Sept 1998, p 63 - 78 Tero Ojanpera and Ramjee Prasad, "An Overview of Air Interface Multiple Access for IMT- 2000 /UMTS", IEEE Communication Magazine, September, 1998, p 56 - 82 Krishna Balachandran, Richard Ejzak, Sanjiv Nanda, Stanislav Vitebskiy, and Shiv Seth, "GPRS- 136: High-Rate Packet Data Service for North American TDMA Digital Cellular Systems, IEEE Personal Communications, June, 1999, p 34 - 47 Stefano Facing, Liangchi Hsu, Rajeev Koodli, Kim Le, and Rene Purnadi, GPRS and IS- 136 Integration for Flexible Network and Services Evolution, IEEE Personal Communications, June, 1999, p 48 - 54 Eshwar Pittampalli, "Third-Generation CDMA Wireless Standards and Harmonization", Bell Labs Technical Journal, July-September, 1999 p 6 - 18 Eric Dahlman, Bjorn Gudmundson, Mats Nilsson and Johan Should, " UMTS/IMT- 2000 Based on Wideband CDMA", IEEE Communication Magazine, September, 1998, p 70 - 79
Free research essays on topics related to: bell labs, data rates, physical layer, high speed, third generation
Research essay sample on Third Generation Bell Labs
