In a previous post I’ve been looking at the concept of the 5G Control Area Set (CORESET). The essence of the post was that the CORESET is the areas in the 5G NR resource grid on the air interface in which scheduling information for downlink and uplink data is sent from the network to mobile devices. The two main parameters a CORESET describes is at which Resource Block (RB) in the frequency domain the control area starts and how many RBs it spans. In this post, I’ll take a closer look at how the information in a CORESET is organized, i.e. how the downlink and uplink scheduling messages are organized.
Happy New Year 2020 to all of you! It’s the time of the year again when it makes sense to take a look back at the last 12 months of 2019 to see which tech things and events ‘have moved me’ during the course of the year. Like in the previous years, it is once again quite a mixed list of things spanning from mobile networks to retro-computing.
In addition to my 60 minute talk about 5G at 36c3, I did a short 5 minute Lightning Talk about the Firefox Certificate Pinner Add-On I started developing this year. If you are interested in better man-in-the-middle attack protection for some of your websites in Firefox, have a look at the Lightning Talk recording here. My pitch starts 2 minutes into the video. This presentation was in English, but German and French translation is contained in the video stream as well (click on the small cogwheel in the lower right and change the language).
There we go, I gave my first talk at a Chaos Communication Congress yesterday together with 33dBm! There were around 2000 people in the room and 950 people streaming the talk live! To my delight, the talk is already online at media.ccc.de in German and also with a live translation to English (click on the cogwheel at the bottom right to change the language). Thanks very much to the translator angels, the video angles, the stage manager, the herald, the hall angels and all others who made this possible, it was great!
Congress is almost here and for those of you not on site there will be live broadcasts and recordings of all talks during the 4 day event. In case you haven’t read enough about 5G on this blog yet, I’m happy to announce that 33dBm and I will be giving a talk on 5G on day 2 (28. December 2019) at 11h30 CET in hall Ada. The picture on the left gives you an idea of the size of the lecture hall so slight nervousness might be possible. Note: While the slides are in English, the talk will be held in German. However, there’s usually live translation available into several languages.
Update: Livestream here: https://streaming.media.ccc.de/36c3/halla
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!
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.
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).
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.
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.