移动通信网 程然
现代移动通信领域失去了一位奠基级人物。语音处理先驱、IEEE Life Fellow Bishnu Saroop Atal 于 8 月 19 日去世，享年 93 岁。对于普通用户而言，这个名字或许陌生，但从 2G 时代至今的每一通蜂窝电话，几乎都建立在他开创的语音编码技术之上。他在贝尔实验室完成的线性预测编码（LPC）与码激励线性预测（CELP）研究，构成了数字语音高效传输的理论基石，深刻改变了全球无线通信的容量格局与通话质量标准。
从印度物理学徒到贝尔实验室核心研究员
Atal 1952 年在印度勒克瑙大学获得物理学学士学位，1955 年于班加罗尔的印度科学理工学院取得电气工程硕士学位。1961 年，他加入位于新泽西州莫里山的贝尔实验室，成为一名通信研究员，早期工作聚焦于说话人识别技术。在全职工作之余，他还于 1968 年在布鲁克林理工学院（现纽约大学坦登工程学院）完成电气工程博士学位，展现出罕见的学术韧性。
上世纪 60 年代，Atal 参与开发了线性预测编码——一种对语音进行分析和压缩的强大方法。LPC 的核心思想是利用人声道的物理特性，用一组时变滤波器参数来刻画语音生成过程，从而以极低的码率重建语音信号。时至今日，LPC 仍是低码率语音编码中应用最广泛的方法，从早期军用通信到今天的移动终端，其影响跨越六十余年。
CELP：改写蜂窝网络容量规则的关键技术
在 LPC 基础上，Atal 持续推进低码率语音编码技术的精细化演进。他提出的多脉冲线性预测编码（Multipulse LPC）显著提升了压缩语音的质量。更具突破性的是，他与同事 Manfred R. Schroeder 合作开发的码激励线性预测（CELP），能在极低码率下产出高质量语音。
CELP 迅速成为现代语音编码的基础性技术，使数字通信系统能以更少的带宽承载语音业务。释放出的效率直接转化为蜂窝网络容量——同样的频谱资源可以支撑更多并发通话。可以说，从 GSM 时代的全速率编码器到 3G/4G 时代的 AMR 系列，再到 VoLTE 语音方案，其算法谱系都能追溯到 Atal 的工作。移动通信在过去三十年间服务数十亿用户，频谱效率是核心约束之一，而 Atal 的贡献恰恰在这一约束上打开了突破口。
【关键数据】
- 逝世年龄: 93 岁，2025 年 8 月 19 日去世
- 贝尔实验室生涯: 1961 年入职，LPC 至今仍是低码率语音编码最广泛使用的方法
- 最高荣誉: 2013 年 IEEE Jack S. Kilby 信号处理奖章
- 院士身份: 1987 年当选美国国家工程院院士，1993 年当选美国国家科学院院士
晚年转向与学术遗产
职业生涯后期，Atal 领导了贝尔实验室的声学与语音研究部门，1994 年被公司授予 Fellow 称号。1996 年 AT&T 贝尔实验室拆分为多个独立研究机构后，他继续在新泽西州弗洛勒姆帕克的 AT&T Shannon 实验室工作，并于次年再度获评 Fellow。2002 年退休后，他出任西雅图华盛顿大学电气工程兼职教授，研究方向扩展至语音处理、语音识别和高维计算等前沿领域，直到晚年仍保持学术活跃度。
Atal 获得的荣誉几乎涵盖了信号处理领域的最高奖项：2013 年 IEEE Jack S. Kilby 信号处理奖章（表彰其“在语音编码领域的根本性和开创性贡献”）、2018 年国际语音通信协会（ISCA）科学成就奖章，以及 2003 年富兰克林研究所奖章。
技术遗产与行业启示
回望移动通信的技术演进史，业界往往将聚光灯投向射频、芯片和网络架构，而语音编码这类“看不见的算法”长期处于公众视野之外。Atal 的离世提醒我们，数字通信大厦的根基正是由这样一批基础研究者奠定的。在 AI 语音合成、神经编解码器（如 Google Lyra、Meta EnCodec）兴起的当下，新一代技术依然在沿用 LPC 的信号建模框架——真正的开创性工作，其生命力足以穿越数代技术周期。从长期看，Atal 留下的方法论遗产仍将持续影响语音通信的下一次跃迁。
出处：Speech Processing Pioneer Bishnu Saroop Atal Dies at 93
英文原文Bishnu Saroop Atal Acoustics and signal processing pioneer Life Fellow, 93; died 19 August Atal was an acoustics and signal processing researcher at Bell Labs in Murray Hill, N.J., and later at AT&T ’s Shannon Laboratory, in Florham Park, N.J. His pioneering work on voice-coding techniques became the foundation for efficient, high-quality voice transmission over cellular networks. He received the 2013 IEEE Jack S. Kilby Signal Processing Medal for “fundamental and pioneering contributions to speech coding.” He joined Bell Labs in 1961 as a communications researcher, and his early work there focused on speaker identification technology. During the 1960s he helped develop linear predictive coding , a powerful method for analyzing and compressing speech. LPC is now the most widely used method for encoding speech at a low bit rate. Atal developed increasingly sophisticated low-bit-rate speech-coding techniques. They included multipulse LPC , which improved the quality of compressed speech. Bishnu Saroop Atal Nokia Bell Labs He also worked with his colleague Manfred R. Schroeder to develop code-excited linear prediction , a method for producing high-quality speech at very low bit rates. CELP became a foundational technique in modern speech coding, letting digital communications systems carry voice using less bandwidth. The extra efficiency expanded cellular capacity, allowing wireless networks to handle more simultaneous calls. Later in his career, he led the acoustics and speech research departments at Bell. The company named him a Fellow in 1994. When AT&T Bell Laboratories split into separate research organizations in 1996, Atal continued his career at the AT&T Florham Park headquarters, and he was named a Fellow the following year. He retired in 2002 and became an affiliate professor of electrical engineering at the University of Washington , in Seattle. There he continued his research in speech processing, speech recognition, and high-dimensional computing. Atal was elected to the National Academy of Engineering in 1987 and the National Academy of Sciences in 1993. He received numerous awards including the 2018 International Speech Communication Association Medal for Scientific Achievement and a 2003 medal from the Franklin Institute . He received a bachelor’s degree in physics in 1952 from the University of Lucknow , in India, and a master’s degree in 1955 in electrical engineering from the Indian Institute of Science , in Bengaluru. While working full time at Bell he earned a Ph.D. in EE in 1968 from the Polytechnic Institute of Brooklyn (now New York University’s Tandon engineering school ), in New York City. Darryl Palmer Jr. Chair of the IEEE Central Illinois Section Senior member, 55; died 30 August Palmer was a dedicated IEEE volunteer, serving as chair of the Central Illinois Section and as the government relations chair of Region 4 . He was a member of the IEEE Industrial Electronics Society and its industrial activity committee. He also served as associate editor of the IEEE Transactions on Industrial Informatics . In 1986, at age 16, Palmer completed a summer internship at NASA’s Glenn Research Center , in Cleveland. He helped develop FoilSim , an interactive educational software program that introduces aerodynamic engineering to preuniversity students. While studying computer science at Cleveland State University in 1996, he joined the university’s Allen-Bradley PLC lab as a research assistant. He designed hardware and software systems for the Glenn Research Center to collect and process thermal wave imaging data. He also designed software for General Motors ’ North American robotic and welding division. In 1999 he completed a second internship at the research center and helped develop EngineSim , an educational software program that models jet engine design and testing. For his work, NASA recognized him with a Space Act Award . In 2000 he earned his bachelor’s degree in computer science and became a software engineer at the Danfoss Drives manufacturing facility in Loves Park, Ill. He worked on embedded control systems for variable-frequency drives and high-power equipment. He also developed sensorless control technology for beam pumps used in the oil and gas industry. In 2014 Palmer and his wife, Alexandra “Sasha” Goodwin , founded Janus Choice, a health technology platform that matches hospital patients with post-acute care facilities. He served as its CEO until the company closed in 2020. From 2018 to 2023, he was a lead software engineer at Adept Coalescence , a startup in Rockford, Ill., focused on developing front-end software for control systems. He then worked in Peoria, Ill., as a control systems team lead at Caterpillar , a manufacturer of construction and mining equipment. Henry Leopold Richter Telecommunications engineer Life senior member, 99; died 12 August Richter was a spacecraft engineer at NASA’s Jet Propulsion Laboratory , in Pasadena, Calif., before starting his o
