Principles and Engineering Design of Third-Generation Mobile Communication Systems IS-95 CDMA and cdma2000

Author: Yu Peng
Publisher:
Publish Date: 2001-01-01
Features: The global mobile communication market is rapidly expanding. Currently, there are approximately 250 million mobile users worldwide, and by the early 21st century, this number is expected to reach 1 billion. Code Division Multiple Access (CDMA) is the fastest-growing digital wireless technology. Between 1997 and 1998, the number of CDMA users worldwide tripled, and it has now reached 30 million. At the current growth rate, CDMA users are projected to reach 50 million by the year 2000. The main markets for CDMA are North America, Latin America, and Asia (particularly South Korea and Japan). Overall, CDMA technology is adopted in nearly 50 countries worldwide. It is not difficult to explain the reasons behind CDMA's success. CDMA is an advanced digital communication technology that can provide 7 to 10 times the capacity of analog technology and 6 times that of TDMA digital communication technology. CDMA systems offer voice quality that far exceeds any other digital cellular technology. This advantage is particularly evident in complex radio frequency environments, such as dense urban areas and mountainous regions. Whether in terms of initial investment or long-term operation, CDMA provides cellular operators with an economical and efficient solution. After 18 months of market development, Personal Communications Service (PCS) providers have demonstrated the market power of CDMA technology in key areas, achieving low costs and high performance in voice quality, system reliability, and mobile phone battery life. Given the long-lasting battery life of CDMA phones and their high-quality voice performance, CDMA service providers have a strong advantage in capturing the market with a minute usage model. A recent wireless platform performance analysis conducted by the Telecommunications Research and Action Center (TRAC) found that CDMA outperforms other digital and analog technologies in all aspects, including signal quality, security, power consumption, and reliability. Although analog technology was adopted earlier, all three digital technologies (GSM, IS-136 TDMA, and IS-95 CDMA) have outperformed analog technology in enhanced service performance. TRAC's research indicates that CDMA surpasses other digital air interface standards in signal security and voice quality. According to TRAC's research, CDMA offers several advantages to users: low power consumption allows a single battery to support 4 hours of talk time and 48 hours of standby time; CDMA's soft switching feature significantly reduces dropped calls compared to GSM and IS-136 TDMA. For some CDMA users, a potential drawback may be certain roaming limitations, but some PCS operators with cellular networks support dual-mode phones that can roam between CDMA and analog platforms. CDMA technology continues to evolve, offering users new advanced services. The data rates provided by CDMA phones are increasing, and new voice codecs offer voice quality close to that of wired communication systems. CDMA terminals can now access the Internet. CDMA service providers will further develop enhanced services on their platforms. There is much discussion in the industry about the performance of 3G data services, and future PCS providers will be able to compete with wired service providers at high access rates. PCS service providers are expected to offer a variety of services, such as Internet and intranet access, multimedia applications, high-speed business processing, and telemetry. CDMA networks provide operators with a smooth transition path to 3G mobile systems. The IS-95B standard is highly flexible, allowing service providers to allocate data in 8 kbps increments within a 1.25 MHz CDMA channel bandwidth. How the allocation is done depends on how the service provider configures the software installed in the network controllers. This means providers can achieve much lower backhaul data rates than 64 kbps, ensuring lower mobile phone power consumption compared to a 64 kbps full backhaul rate. While GSM and IS-136 TDMA operators are also working to ensure they do not fall behind in data services, CDMA appears to have a clear advantage in providing higher speeds through existing infrastructure. Another advantage for CDMA operators is the potential to enhance fixed wireless service capabilities. CDMA extends the spectrum, enabling fixed services to be offered on top of mobile communication infrastructure. Some operators are developing terminals that can switch between fixed and mobile services based on the user's location. A universal phone can function as a cordless phone at home and as a mobile phone when away. The evolution toward 3G systems also opens the door to Wireless Local Loop (WLL) applications, which can access the Public Switched Telephone Network (PSTN) and Public Data Network (PDN), making it easier to control and utilize network resources. The evolution to 3G systems will also pave the way for convenient global roaming, service portability, location-based ID and billing, and direct global access. 3G technology may even support seamless satellite network interworking. Due to the numerous benefits of CDMA, once a shared strategy is implemented, operators adopting this platform will clearly have various opportunities to develop their businesses. The question is when they will carefully consider launching these new features to the market. An advanced hybrid technology has recently been proposed, tested, and evaluated, combining the CDMA air interface with a GSM network. GSM operators using IS-95 CDMA wireless interfaces instead of TDMA wireless interfaces during network expansion have saved more than 60% in costs, as this integrates CDMA's spectral efficiency with all of GSM's features, including seamless roaming and network services. GSM-CDMA technology enables operators to serve multiple market economies and provide different services on a single network platform. Beyond serving as an economical and efficient network expansion solution, GSM-CDMA also paves the way for the evolution of 3G services, including high-speed data, multimedia, and mobile/fixed converged services. As demonstrated by the proposals submitted by the European Telecommunications Standards Institute (ETSI), the Japanese Wireless Industry Association (ARIB), and the Telecommunications Industry Association (TIA), 3G systems have chosen CDMA. The cdma2000 standard, based on IS-95B, provides circuit-switched voice services and high-speed data services with rates ranging from 144 kbps for mobile users to 2 Mbps for stationary users. It is important to note that cdma2000 is the core proposal submitted by TIA for IMT-2000, and support for cdma2000 is not limited to North America. Operators in South Korea are likely to use existing CDMA technology to provide services similar to 3G. Today's CDMA technology can achieve mobile data rates of 114 kbps within 10 years and fixed peak rates exceeding 1.5 Mbps, all without compromising voice transmission quality or requiring additional spectrum. This has a significant impact on most spectrum-constrained operators, as doubling capacity in a 1.25 MHz channel structure while achieving 1.5 Mbps data rates appears highly attractive. This book is