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.


March 4, 2014

Recent Readings: 2014 Week 09

Filed under: C/C++, embedded systems, microcontroller, telecom, Uncategorized, wireless — larryang @ 12:38 PM

Two large FM two-way units in the trunk of an automobile, built by Motorola in 1940. Two-way radio’s first use was with municipal police and fire departments..



Subcribe to Embedded Systems Weekly, curated by @embedsys

January 31, 2014

Recent Readings: 2014 Week 4

Society and Policy:



Embedded Development:

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:

July 12, 2013

Recent Readings Week 22

Filed under: code quality, programming, telecom, wireless — larryang @ 11:03 AM

IMT-Advanced explained – *I want to slap the T-Mobile spokes model in back of head NCIS style* – what is being marketed as 4G is more honestly 3.5G, what’s marketed as LTE is only 4G-capable and what being called 5G (LTE-Advanced?) is really just full 4G.


Tech News

July 11, 2013

Recent Readings Week 21

Filed under: Agile, embedded systems, engineering, professional, wireless — larryang @ 1:50 PM

Antisoldering: How to Fix Your Mistakes and Salvage Free Parts




June 28, 2013


Filed under: wireless — Tags: , — larryang @ 8:10 PM

Hanging out at Makerbar, I was researching and picking brains on my next project: Software Defined Radio (SDR). I was inspired by a recent IEEE Spectrum article to check it out. The USB dongle costs around twenty bucks, and it can be easily combined with a Raspberry Pi.

From the article comments and research on the web, I ordered from NooElec their R820T.

Also, fellow Makerbar buddies recommended the HackRF Jawbreaker. I’ll keep an eye out for when it comes out.

July 28, 2011

Building a Subversive Grassroots Network – IEEE Spectrum

Filed under: engineering, telecom, wireless — Tags: , — larryang @ 11:05 AM

Is this the real Internet 2.0? Building a Subversive Grassroots Network – IEEE Spectrum.

I think I’ve found my favorite next big thing in technology: mobile ad hoc networks, or MANETs. Open source software, open protocols, etc. I’m going to have to check out the Optimized Link State Routing (OLSR) protocol.

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.

October 5, 2010

How a Conversation over Mobile Telephony Works

Filed under: humor, telecom, wireless — larryang @ 11:48 AM

Abstruse Goose » Hello.

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