Ubuntu and Bluetooth Mice – The Cherry MW 8 ADV

Ever since I can remember, my wireless mice came with a USB dongle. They shrunk in size over the years so this straight forward approach has served me well. But the number of USB ports on notebooks is on a steep decline. Put recent security vulnerabilities on top that have been found in proprietary protocols and the manufacturer’s inability to deliver a fix that addresses them all made me look for a wireless mouse that uses Bluetooth and thus no longer requires an extra USB dongle. Obviously it has to work with Ubuntu Linux.

Continue reading Ubuntu and Bluetooth Mice – The Cherry MW 8 ADV

AeroMobile 3G on Planes

When I was recently on a long-haul flight I accidentally didn’t activate flight mode on my smartphone and to my surprise the device registered to an on-board 3G network of AeroMobile once we were at cruising altitude. I was really glad my home network operator of choice has a landing page to block mobile data outside the EU until I confirm because as I already discussed here, 2G/3G/LTE mobile network use on planes and ships is still super expensive. Calling a price of close to one Euro per 50 kb of data ‘modern piracy’ is probably an understatement.

Continue reading AeroMobile 3G on Planes

What Is Wifi WPA-3 Personal Mode Authentication?

First Wifi products are now coming to the market that support WPA-3 personal mode authentication and ciphering key exchange so I thought it would be a good idea to have a closer look at how it works and why an update was necessary.

To answer the last question first: WPA-2 PSK (Pre-Shared Key) uses the Wifi password as basis for all authentication and encryption exchanges between Wifi access point and clients. Many networks only use short and thus very weak passwords, and brute forcing them offline without interaction with the network has become quite feasible with current generation computing hardware. WPA-3 tries to address this issue with a new authentication scheme referred to as ‘Simultaneous Authentication of Equals’ (SAE). It is based on Diffie Hellman Elliptic Curve Public/Private keypair generation algorithms that are also used for generating ciphering keys for secure HTTPS connections today.

The mathematical details of the process can be found in RFC 7664 and a good higher level description can be found here. Still, it took me quite a few hours to understand the principles, so I though I’d assemble a less mathematically focused description on the basics of  WPA-3 SAE and how it is used in practice:

Continue reading What Is Wifi WPA-3 Personal Mode Authentication?

The Range of 5G Band n78

Over the past weeks I’ve noticed a few articles, posts and videos on the net that were looking at first 5G deployments in the wild and were commenting on the seemingly limited range of the 3.5 GHz band that is used for 5G NR. Some people noted that only 200m from the base station they could no longer use 5G and fell back to LTE. Therefore, they concluded, the range of the n78 frequency band must be very limited. But is this really so?

Continue reading The Range of 5G Band n78

Conference Calling Without Hold

I am probably one of the few people on the planet who uses ordinary conference calling quite a lot. When in a call with someone it is sometimes helpful to add a third person to the conversation. This is done by putting the other party on hold while the call is established to the third person. Once the third person picks up you have to explain that you have someone on the other line and would like to make a conference that person in. In most cases that explanation takes many additional seconds during which the other side is still on hold. In other words, this solution is far from ideal in practice.

Continue reading Conference Calling Without Hold

The US Will Get 3.5 GHz Spectrum for 5G – But Not Much

The spectrum situation for mobile services in the US has always been different from much of the rest of the world. More often than not, US network operators have to cobble together 5 and 10 MHz chunks of spectrum for their customers while in the rest of the world, aggregating 20 MHz channels is the norm rather than the exception. For 5G, the US again took a different path with mixed results so far. However, it now seems to be partly changed to match the rest of the world.

Continue reading The US Will Get 3.5 GHz Spectrum for 5G – But Not Much

Aurora – Android Without the Play Store

Image of the Aurora store app in F-DroidBack in February I wrote a post on how to download and install apps from the Google Play store to an Android device without a Google account. At the time  I was using ‘Yalp’, which is ‘Play’ spelled backwards. Unfortunately, the app became a bit unreliable over the months so I was very happy when I found an incredibly good replacement recently after reading about ‘Google alternatives’ on Kuketz-Blog (in German).

Continue reading Aurora – Android Without the Play Store

The State of Open Source LTE

Open source implementations of pretty much all GSM network and UE components have been available for quite some time now and there are people that do use the software for private and commercial purposes. For many years now, for example, the Chaos Communication Congress has a dedicated private GSM network and, in recent years, a UMTS setup was added. And now, and I am very happy about this, the first successful attempt to also set-up a private LTE network has taken place at this years cccamp#19.

Continue reading The State of Open Source LTE

State of Microwave Backhaul – Part 2

‘Because We Can’ is the motto when it comes to technology and Chaos events so when cccamp19 came around there were no less than three backup microwave links available to the land based temporary fiber cable to the next POP that rodents find quite attractive. In the first post on the topic I’ve described the first two that bridged a distance over 10 km and offered a bandwidth of 10 Gbit/s. For this post I’ve collected some technical details about the microwave link they had all the way to Berlin which was 57 km away!

Continue reading State of Microwave Backhaul – Part 2