Profile of Prolific Inventor & ComSoc NA Director Yigang Cai

Introduction and Overview

For the third time in four years, ComSoc NA Director Yigang Cai, PhD was honored with the 2011 Bell Labs Inventors Award in the Product and Services group category.  His contributions cover Messaging, Mobile Applications and Mobile Service technology and markets.  The annual Bell Labs Inventors Award recognizes and honors individuals who exemplify excellence, innovation and creativity by outstanding patent contributions across Alcatel-Lucent (ALU).

In addition to being a prolific inventor, Yigang did a splendid job as ComSoc NA Distinguished Lecture Tour (DLT) Director in 2009-2011.  As ComSocSCV Chair, this author was very impressed with Dr. Cai’s dedication and strong commitment to that volunteer job.  This year (2012), we’ve collaborated on several issues that improved operations of local ComSoc NA Chapters.

About Yigang Cai, PhD

Yigang Cai was an Associate Professor in Department of Mechanical Engineering at Zhejiang University before he moved to the United States in 1989. He obtained his BS, MS and PhD degrees from Zhejiang University, Hangzhou, China.  Yigang joined AT&T-Bell Labs in 1995.  He has worked as a systems engineer in his Lucent, and Alcatel-Lucent (ALU) career and engaged in research and development of many wire-line and wireless communication products. Dr. Cai became a Distinguished Member of Bell Labs Technical Staff in 2000. 

An Inventor Par Excellence!

As of July 31, 2012, Yigang has filed 231 US patent applications, and had 145 patents granted worldwide.  That’s a phenomenal total by any stretch of the imagination!

Yigang’s numerous invention submissions address a wide range of technology areas.  During 2010- the most recent ALU Inventor time period- Yigang’s contributed total forty-three patent filings:

  • Twenty-nine contributions address VOIP and Web Applications such as Location Based Services, Messaging, Subscriber Data Management and Profiling, Billing/Payment Systems, IMS Solutions and VoIP Infrastructure.  
  • Eleven contributions address Mobile/Wireless Core Networks including the Mobile Switching Center, Mobility management, the Evolved Packet Core,  Handsets,  3GPP Services, and LTE.
  • Two contributions address Video and Media Applications such as Multimedia Applications, and TV Video Applications.
  • One contribution addresses Service Aware Networks such as Multimedia Gateways.


Many of Yigang’s contributions have been implemented in ALU products and delivered to customers such as Verizon Wireless (VZW). Others are under development so that they can be included in new ALU products that are expected to be delivered to customers, including VZW and AT&T, in the near future.

Yigang’s contributions impact ALU products that include LTE SMS GW, SMSC, MSC,  5119 BMGW, real time payment system (8610 ICC and 8620 SurePay) policy control manager (5780 DSC), Universal Message Center. Yigang continues to be one of the most prolific inventors in ALU. Yigang’s contributions are not only numerous but are also high in quality. In particular, thirty-one of Yigang’s forty-three contributions have been designated by ALU as “high quality” (i.e., internal rank 1 or 2) and are scheduled for international patent filing.  Several contributions have been submitted to standards development organizations for potential adoption.  Moreover, substantial contributions have been made in ALU focus areas, which include: Messaging, Subscriber Data Management and LTE.  Many of those are likely to be implemented in ALU products. 

Yigang is one ALU employee who surely does not work in a silo. While several contributions are solo efforts, many are collaborative efforts with a variety of different inventive teams, with other co-inventors of individual inventive teams being located in China, Europe, the United States, or all three continents.  For many of these border-crossing collaborative invention teams, Yigang is the lead US-based co-inventor.

An ALU employee that worked with Yigang and drafted several of his patent applications said, “I find him extremely collegial, always willing to share his expertise so that the best end-product/result is achieved. He is responsive throughout the patent process, responding faithfully and timely despite other, enormous demands on his time.”

That’s a very powerful testimonial!  ComSoc is most fortunate to have Yigang Cai as our NA Director.  If you have the opportunity to work with him, you are most fortunate!

Appendix:  Yigang’s top 10 patents in 2010 (the most recent ALU time frame)

In the considered ALU time frame, Yigang contributed to forty-three positive filing decisions.  Ten contributions currently considered of most commercial import follow:

1. Message Delivery over LTE Networks (3GPP Services).
Contribution embodiment/s address LTE messaging strategy, architecture and methods and are the basis for a brand new ALU product LTE SMS GW which will be deployed to VZW network in 2010.

2. Sequential Message Delivery for FDA Processing and Store-and-Forward Processing (Messaging).
Contribution embodiment/s propose a key evolution with a FDA/MDA configuration of SMS/MMS network, were built into ALU’s SMSC release 11.0 and deployed to the VZW network beginning in November of 2009 when VZW began a network upgrade from the current single SMSC to a FDA/MDA configuration. ALU has 58 pair of SMSC (~50 sites) in the VZW network and the configuration of most will be upgraded. ALU revenue confirmed from VZW will be ~$40 million in 2010-11 for 4 geo-sites.  The complete network upgrade is expected to take at least 5 years and while ALU does not have VZW’s commitment yet, the upgrade’s revenue impact is conservatively estimated at ~$120 million.

3. Voice Notification to the Destination of a Text Message That is Engaged in a Voice Call (Messaging).
Contribution embodiment/s create a ‘whispering’ SMS when an end user is in a voice session.  ‘Whispering SMS’ is expected to be a great application in the near future.

4. SIP Response Encapsulation for SMS Delivery over IP Network (Messaging).
Contribution embodiment/s provide a new method in SIP messaging so that SMS can be delivered over IP networks, eliminating unnecessary delivery acknowledgement/ report messaging and handling. The method can be used for other SIP applications and standards evolution. Its first application will be in the VZW network.

5. Messaging Waiting Notification to External Message Center (Mobile Switching Center).
Contribution embodiment/s were a key MSC feature for the Verizon Wireless (VZW) network.  FDA/MDA evolution.  Embodiments were implemented in ALU MSC and delivered to VZW.

6. SMS Message Delivery over Broadband Data Networks (Evolved Packet Core or EPC).
Contribution embodiments provide a new direct SMS delivery over EVDO (3G) network when bypassing MSC and SMSC. Embodiments were implemented in a new ALU product 5119 BMGW and deployed in VZW network in November of 2009. Similar embodiments were deployed for AT&T in 2011.

7. A Method for Delivering Dynamic Policy Rules to an End User, According on Subscribers Account Balance and Service Subscription Level (Billing).
Contribution embodiment/s provide a new method for interactions between OCS and PCRF in 3GPP policy and charging control (PCC) for mobile broadband services, IPTV and other applications. The contribution is an ALU value position to enhance the PCC capability on the real time payment system (8610 ICC and 8620 SurePay) and the policy control manager (5780 DSC).

8. Text Messaging over an eHRPD Network (Messaging).
Contribution embodiment/s provide a SMS/MMS message deliver over LTE/eHRPD networks. The contribution is in a road map and will be implemented in a new ALU product Universal Message Center for North America and other regions’ customers.

9. Charging Method Selection for Service Data Flows Based on the Data Services Being Requested (Billing).
Contribution embodiment/s allow LTE gateways and the PCEF to consult charging rules to the PCRF when providing flow and service data to the PCRF, during establishing and updating IP-CAN.  The contribution will significantly enhance 8610 ICC and 8620 SurePay by involving LTE/EPC network charging.

10. Registration Notification for SMS over LTE (Mobile Management/ Evolved Packet Core).
Contribution embodiment/s provide a method for subscriber databases (HSS and/or AAA) to push a registration notification to IP-SM-GW when subscriber registers/ deregisters to LTE/EPC networks.  The contribution will be built in a roadmap into HSS/AAA and a new ALU product Universal Message Center.

Yigang with ALU CEO Ben Verwaayen: