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| IS-95 (CDMA) | |
|---|---|
| Name | IS-95 (CDMA) |
| Developer | Qualcomm |
| Introduced | 1995 |
| Predecessor | TDMA |
| Successor | CDMA2000 |
| Standards | ANSI-41 |
| Frequency | 800 MHz, 1900 MHz |
| Modulation | QPSK |
| Multiple access | Code-division multiple access |
| Voice codec | QCELP |
IS-95 (CDMA) is a digital cellular air-interface standard developed by Qualcomm that introduced Code Division Multiple Access to commercial mobile telephony. It replaced earlier analog standards and coexisted with contemporaneous digital systems, enabling increased capacity, improved voice quality, and resistance to interference across North America and parts of Asia. IS-95 influenced subsequent generations of mobile standards and catalyzed global adoption of CDMA-based technologies.
IS-95 emerged as a commercial implementation of spread spectrum techniques and offered a CDMA-based alternative to Time Division Multiple Access systems like the earlier Global System for Mobile Communications developments and Interim Standard 136. The specification aligned with North American signaling frameworks such as American National Standards Institute documents and was integrated into operator networks run by carriers like Verizon Communications, Sprint Corporation, and regional providers in markets including South Korea and Japan. Its design emphasized soft handoff, power control, and capacity efficiency that informed successors such as CDMA2000 and influenced international bodies including the International Telecommunication Union.
Development traces to Qualcomm research in the 1980s and early 1990s, building on military and academic work at institutions such as Massachusetts Institute of Technology and Stanford University. Early demonstrations involved collaboration with companies like Motorola and regulatory engagement with agencies including the Federal Communications Commission and standards work via Telecommunications Industry Association. Commercial deployments began mid-1990s as operators like Sprint Corporation and regional carriers in Taiwan adopted IS-95 handsets manufactured by vendors such as LG Electronics, Samsung Electronics, and Nokia. IS-95's roadmap intersected with corporate actions by entities like AT&T Inc. and spectrum allocations influenced by ministries in India and China.
IS-95 used direct-sequence spread spectrum employing pseudo-random noise codes and quadrature phase-shift keying; modulation and channelization drew on work by researchers at Qualcomm and academic groups at University of California, Berkeley. Carrier frequencies commonly used the 800 MHz and 1900 MHz bands coordinated with national regulators like the Federal Communications Commission and Industry Canada. Voice compression used codecs such as QCELP developed in collaboration with standards committees including 3GPP2 precursors and telecommunication firms like Lucent Technologies. Error control and channel coding referenced algorithms from institutions including Bell Labs and cryptography research at MIT Lincoln Laboratory.
IS-95 networks comprised base stations, mobile switching centers, and packet data gateways interoperating with signaling systems such as ANSI-41 and location services tied to databases like those used by TeleAtlas and Navteq for service routing. Base station equipment vendors included Ericsson, Nortel Networks, and Alcatel-Lucent, while core network elements were supplied by companies like Siemens and Huawei Technologies. Operator management integrated business systems from Oracle Corporation and billing platforms provided by Amdocs. Roaming arrangements involved agreements among carriers including Deutsche Telekom and Vodafone Group.
The air interface implemented forward and reverse link channels with pilot, sync, paging, and traffic channels using Walsh codes and long PN sequences based on spread-spectrum research from Johns Hopkins University labs. Protocol layers mapped onto radio resource control and link-layer techniques that paralleled work in standards developed by bodies such as IEEE and committees influenced by 3GPP2 stakeholders. Handoffs leveraged soft and softer handoff procedures linked to base station sectorization by companies like Alcatel-Lucent and tested in field trials with carriers including Sprint Nextel and Bell Canada.
IS-95 supported voice services, short messaging, and early packet data services such as 1xRTT precursors and circuit-switched data used by enterprise customers of IBM and retail consumers via handset ecosystems from Sony Ericsson and Kyocera. Supplementary services included caller ID integration with switching platforms from Siemens and prepaid billing systems deployed by regional providers like T-Mobile US subsidiaries. Value-added offerings such as location-based services engaged mapping firms including Google in later stages and enterprise mobility solutions integrated with corporate IT from Microsoft and SAP.
Widespread IS-95 deployments in the United States, South Korea, and parts of Latin America drove handset and infrastructure markets involving manufacturers like Qualcomm, Motorola Solutions, and Samsung Group. The standard influenced regulatory spectrum policy debates in forums such as the Federal Communications Commission proceedings and international spectrum harmonization efforts at the International Telecommunication Union. Its technical innovations informed successor technologies—CDMA2000 and elements of W-CDMA—and impacted service competition among operators including Verizon Communications and Vodafone Group, shaping handset ecosystems with companies like Apple Inc. later entering mobile markets.
Category:Mobile phone standards