It’s been six months since my last book review on computing history and there are a number of reasons for it. Back in June I started reading ‘The Dream Machine’ by M. Mitchell Waldrop, a computing history book focusing on the life of J. C. R. Licklider. The 50th anniversary of the Apollo 11 moon landing kept me from making quick progress as I literally spent 6 weeks on that in summer. And then, this book, published in 2001 and almost 10 years in the making, is a monumental piece of work that takes quite some time to read and enjoy all by itself.
5G – How To Control Beam Forming – Channel Measurements
When it comes to making the most out of a radio channel, 5G NR goes to even greater lengths than LTE. There are lots and lots of mechanisms for the base station and the UE to analyze current channel conditions and, based on the results, optimize their transmitter and receiver settings accordingly. Quite a number of posts over at Sharetechnote go into the details of this and it’s easy to loose sight of the basic mechanisms at work. So I thought I’d do a quick post on how Channel Measurements for MIMO and beamforming in 5G NR works in principle.
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How To Open ‘Protected’ PDFs on Linux
I’ve received several PDF documents lately that would only open in Adobe’s Acrobat Reader without being asked for a password. In Acrobat Reader, the document is then usually ‘protected’ against printing, annotation and/or other things one does with a PDF. Unfortunately that doesn’t help me much because I won’t install the closed source Adobe Reader on my notebook. No way.
But here’s a quick fix: Files that Evince and Okular can’t open can still be viewed with the Firefox PDF viewer. Nice, but it’s still a major pain. So I spent some time to see if this annoyance could be removed. And indeed there is a simple solution:
LTE Congestion Behavior – Part 2
Recently, I attended a huge fair with 10.000 people crammed into a 16.000 m2 hall that had indoor LTE coverage from 3 network operators and little Wifi for public use. From a mobile network point of view it doesn’t get much ‘worse’ than this so I spent some time to have a look how one of the networks was coping with such a huge number of people and their devices.
LTE – When The Downlink Sucks
Sometimes I wonder if the good times with LTE are about to be over!? In the past 12 months I increasingly get into situations in which an LTE network is available with good signal quality but is heavily overloaded and at the point of becoming unusable.
The Story and Sounds of the Voyager Golden Record
A bit off topic perhaps but never mind: I was recently pointed to the website of ‘2000 Hertz’, a podcast on sound and music. Not really my domain but they recently had an episode on the sounds on Voyager 1 and 2’s golden records. I of course knew about the records and that Carl Sagen was one of the masterminds behind them but had little further background. This podcast episode magically mixes the sounds and stories behind the records and is an absolutely must hear for space enthusiasts. Enjoy!
How To Get Nationwide 5G Coverage and a 5G Core Network
So here we are in the fall of 2019. 5G networks have started around the globe and pretty much all of them use high-band spectrum at 3.5 GHz (band n78). US operators are experimenting with 2.5 GHz and mmWave spectrum in combination with an LTE anchor cell. The anchor cell is usually either at 1.8 GHz (band 3) or 2.6 GHz (band 7) and perhaps in some cases also on the 800 MHz low-band (band 20). That is all nice and well but 5G on 3.5 GHz won’t cut it when it comes to nationwide coverage. For that, 5G also needs to use the mid- and low-bands. But how do we get there?
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LTE TTI Bundling in the Wild
Already back in 2009 (!), I wrote a blog post on LTE’s TTI-bundling feature. It was supposed to be used to improve cell edge scenarios when a device’s uplink power would not be sufficient anymore. In particular it was seen to improve VoLTE speech quality. Quite a bit of thinking ahead because we were far away from VoLTE in practice back then. Over the years I haven’t seen TTI Bundling in the wild until recently.
My First Semi-Autonomous Drive Experience
When I was recently in the US, I had the opportunity to drive a Toyota RAV4 that came equipped with semi-autonomous driving features. A welcome opportunity to experience first hand over a few hours in dense metropolitan areas and overland routes the current state of driver assistance technology.
When Wideband Was 50 kbit/s
For months I am trying to get through an amazing book ‘The Dream Machine’, a biography of computing pioneer J. C. R. Licklider. The ‘problem’ with the book is that it is so packed with interesting stories about computing and networking from the 1950s to the 1980s, that there is hardly a page at which I don’t deviate to get some more background information. I am about halfway through and again got stuck when I started some background research on the early days of the Arpanet. This is when I stumbled over an incredibly interesting video I thought I should mention here.