Book Review: Mobile Unleashed – The History of ARM

mobile-unleashedAfter having taken a closer look at x86 processor with “Inside The Machine” I came across “Mobile Unleashed“, a book about the history of a non-Silicon Valley company and technology for a change that has significantly shaped the world of computing as we know it today: ARM.

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First Wifi Access Point With PMF Frames Sighted

In the past few years a number of hotel chains have experimented with Wifi De-associaten attacks to force venue guests off their own Wifi access points. Fortunately the FCC has responded quite sharply and so I haven’t seen further reports about such behavior in the wild. FCC rulings are good, countermeasures are even better. So far I haven’t seen them “in the wild” which was a bit disappointing. Up until now.

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VoLTE – Some Thoughts On Bandwidth Negotiation

In the previous blog post on VoLTE I discussed how speech codecs are negotiated during connection establishment. VoLTE uses the AMR and WB-AMR codecs that are adaptive and can encode the voice stream in several data rates and qualities. In the case of WB-AMR, voice streams can be sent with data rates between 6.6 and 23.65 kbit/s. In practice, many networks limit the codec rate to 12.65 kbit/s in the case of WB-AMR and to 12.2 kbit/s for the narrowband AMR codec. Let’s have a closer look how that is done in practice.

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Microcode Implementation In A Real Processor

One of the biggest revelations I had during my (ongoing) journey to discover how a processor really works is to find out how that mystical microcode in a CPU is implemented. Things culminated in the 4-Bit Nibbler Do-It-Yourself CPU project that uses a microcode ROM in the control part. For understanding how microcode works it can’t get much better than that. Except…

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LTE and Quadcopters

Quite high on my list of things to do and get into when I have a bit of time are quadcopters. Well, actually that topic is on my list for years now but there’s always something else to do. Anyway today I came across a Quadcopter project with LTE connectivity for control. Cool idea, have a look here.

Speaking of quadcopters, another project that is on that wishlist of mine is the Crazyflie. Everything is open in this project, so it has a special appeal to me. That quadcopter might be a bit too small for LTE connectivity, however.