3G cellular network

Second-generation (2G) cellular networks had brought digital voice to mobile phones, but data transmission remained painfully slow. Early mobile internet over GSM delivered perhaps 9.6 kilobits per second—fine for text messages, useless for anything more. The Internet was transforming computing, but mobile devices remained largely disconnected from it.

Third-generation networks aimed to bring mobile broadband. The International Telecommunication Union's IMT-2000 specification required at least 200 kbps data rates, with targets of 2 Mbps for stationary users. Multiple incompatible standards emerged: CDMA2000 in North America and parts of Asia, UMTS/W-CDMA in Europe and most of the world, and TD-SCDMA in China. Each represented different evolutionary paths from existing 2G infrastructure.

Japan's NTT DoCoMo launched the world's first commercial 3G network in October 2001, using W-CDMA technology. The timing reflected Japan's unique position: high population density justified infrastructure investment, and DoCoMo's i-mode service had already demonstrated consumer appetite for mobile data. European and American deployments followed, though more slowly than the optimistic projections of the late 1990s telecom bubble.

The adjacent possible required advances in semiconductor technology, particularly RF CMOS, which allowed complex signal processing in mobile devices at acceptable power consumption. Spectral efficiency improvements—squeezing more bits through limited radio bandwidth—came from CDMA spread-spectrum techniques. Base station infrastructure needed upgrading to handle data traffic. And critically, content and applications had to emerge that made mobile data worth paying for.

Standards competition reflected geopolitical interests. Qualcomm's CDMA patents generated billions in licensing fees, making standards choice a matter of national industrial policy. Europe backed UMTS partly to avoid American patent dependency. China developed TD-SCDMA specifically to create domestic intellectual property. The technical merits of each approach mattered less than the economics of standards control.

Geographic deployment patterns reflected regulatory and market structures. Japan led because NTT DoCoMo could invest ahead of demand. South Korea followed quickly, driven by technology-forward industrial policy. European deployment was slower due to spectrum auction costs—the UK's 2000 spectrum auction extracted £22.5 billion from operators, leaving less capital for infrastructure. The US lagged further, fragmented among competing carriers and standards.

3G enabled the first wave of smartphone applications. Mobile email became practical. Web browsing, while slow, was possible. App stores could deliver content over the air. When Apple launched the iPhone in 2007, 3G networks (specifically the HSDPA enhancement) provided adequate connectivity for the smartphone revolution. 3G didn't cause smartphones, but it was a necessary precondition—the infrastructure upon which mobile computing could build.

By 2025, most 3G networks had been shut down or were being decommissioned, their spectrum reallocated to 4G and 5G. The technology that once represented cutting-edge mobile broadband had become obsolete within two decades, displaced by its own successors.