WirelessMoves

Generally, I’m pretty happy with the backup strategy I have for my devices and my servers. I have several geo-redundant copies of my data and rotate backups frequently. I even use SSDs to clone my notebook installation and data so I can hit the ground running should the worst happen. But there is always more one can do. Things my backup strategy did not address very well so far, however, was accidental deletion of data only noticed days or weeks later or protecting against encryption trojans that could alter data that would then replicate into at least the latest backup if not caught in time.

An approach to protect myself against such scenarios would be incremental backups so I could go back to any state over weeks or months. Perhaps Borg Backup for Linux, of which I heard in Lightning talks during the past two Chaos Communication Congresses could complement my backup strategy!? So when I finally gave this open source package a try recently, it totally blew me away!

Continue reading Borg Backup

Carrying on from the previous post on things that are different in 5G NR compared to LTE, the CORESET comes to mind. When I first heard the term I had to think of 1960s core memory, a core dump and other memory related things. But the 5G CORESET is something entirely different.

Continue reading What is a 5G CORESET?

Back in the ‘good old days’, things were simple on the LTE air interface. It served one purpose and one purpose only: Fast Internet connectivity. This allowed to keep most things about the air interface static. The 5G NR interface on the other hand tries to keep all options open for the future and the only constant used in the spec seems to the speed of light. Everything else has been kept flexible. In this and a number of future post I’d like to describe a number of concepts that have been standardized for the 5G NR air interface that do not exist in LTE. So let’s start with the Bandwidth Parts (BWPs).

Continue reading What Are 5G Bandwidth Parts?

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.

Continue reading Book Review – The Dream Machine

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.

Continue reading 5G – How To Control Beam Forming – Channel Measurements

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:

Continue reading How To Open ‘Protected’ PDFs on Linux

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.

Continue reading LTE Congestion Behavior – Part 2

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.

Continue reading LTE – When The Downlink Sucks

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!

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?

Continue reading How To Get Nationwide 5G Coverage and a 5G Core Network