Larry's Notebook

August 11, 2014

HOPE X – RF and Cellular talks

Filed under: free and open source, hacker culture, networks, telecom, wireless — larryang @ 2:48 PM

Community Owned and Operated Cellular Networks in Rural Mexico” – slides here. The presenters provide cellular service to rural Mexican communally governed communities.

The next day, the presenters had a workshop on “How to Build and Run Your Own Cellular Network“.

The equipment is less than ten thousand US dollars, running open source software. Its fairly small and easily placed on a tree or bamboo. There is quite a bit of software work to be done, especially services that involve interfacing with the publicly switched telephone and cellular network (PSTN).

Building an Open Source Cellular Network at Burning Man” by Geeks Without Borders – slides here. The presenters talk about how they provided service for a community of fifty thousand who appear overnight. Burning Man provides a good way for experimenting and testing for scenarios such as disasters and refugee camps.


HOPE X: Citizens Band Microwave Spectrum And Free Internet For All – Citizens Broadband Radio Service, with lightning talk transcript and slides at – I missed this talk, but am including it since I found it interesting.


November 15, 2013

Webinar: Building and Running Community Cellular Networks with OpenBTS

Filed under: free and open source, networks, telecom, wireless — larryang @ 2:08 PM

Course: Building and Running Community Cellular Networks with OpenBTS.

  • OpenBTS: An open-source GSM/SIP gateway that converts 2G GSM into standard VoIP protocols. 
  • FreeSWITCH: An open-source PBX/SIP Switch that routes all SIP traffic in the network.
  • smqueue: An open-source Short Message Service Center (SMSC) that routes SMS messages. 
  • sipauthserve: An open-source Home Location Register (HLR) that maintains the Subscriber Registry (SR)


See also:

October 11, 2013

Recent Readings Week 41

Filed under: embedded systems, FPGA, hacker culture, networks, professional — larryang @ 2:08 PM

Social Implications of Technology




February 13, 2012

The Great Disk Drive in the Sky: How Web giants store big—and we mean

Filed under: networks — larryang @ 11:54 AM

The Great Disk Drive in the Sky: How Web giants store big—and we mean.

Covers what Google, Hadoop DFS, Amazon and Microsoft solutions. It’s a lot like cache design- considerations include size of data, frequency of reads vs. writes. I think is the hardest engineering challenge is avoiding a single point of failure and making the system truly distributed while maintaining coherency in a low overhead and timely manner.

December 8, 2011

EE Times’ 20 hot technologies for 2012

Filed under: embedded systems, engineering, networks, telecom, wireless sensor networks — larryang @ 10:56 AM

EE Times’ 20 hot technologies for 2012.

I’m most interested these technologies: LTE (my day job), wireless sensor networks and internet of things. The latter two are tied together by protocols, enabled by open source software and open hardware and implemented in embedded systems.

I think wireless sensor networks will be of the greatest value as humanity creates nervous systems for cities and regions. For example, a single air quality sensor node in Beijing is causing quite a political and media stir.

I will be keeping an eye our for more events like the Eyebeam Workshop: NYC Open Sensor Network and events sponsored by Internet of Things New York City Meetup.

April 26, 2011

WOCC 2011 Lookback

Filed under: networks, telecom, wireless, wireless sensor networks — larryang @ 1:22 PM

I attended the Wireless Optical Communications Conference over a week ago at NJIT. A colleague presented a paper “High-order Modulation scheme based on combinational QPSK accelerators for HSPA Evolution in UE“; I’m thanked in the acknowledgements.

Several things that stuck with me:

  • Designing for the other 90% (a term I’m using viaCooper-Hewitt).
  • Implementing an “Internet of Things” as communications become dominated by machine to machine interaction as opposed to person-to-person. Network protocols and designs to reflect varied applications such as wireless sensor networks and smart grids.
  • Providing mobile data access to high speed travel on trains and planes.

September 13, 2010

Structural Problems Enabling Computer Crime

Filed under: C/C++, computer architecture, networks, programming, telecom — larryang @ 12:37 PM

It’s kind of funny how science-fiction writers have the best insights and perspectives on technology. Stross’s blog entry covers decisions made, that in hindsight, made computer security hard. These design oversights range from hardware, to low level programming to the human factor. His example of the iPad also provides insight into why Apple is so damned successful.

Where we went wrong – Charlie’s Diary.

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