Quite a number of 3G UMTS networks have been upgraded over the past year to HSDPA (High Speed Downlink Packet Access) which boosts data transmission rates from about 384 kbit/s to over 1 MBit/s in a first step. The second step of HSDPA, with data rates of over 3 MBit/s, has also gone life in … Continue reading 3.5G HSDPA in the US
All answers have been held as short as possible and require an understanding and study of the corresponding chapter of the book. Answer 1: The basic concept of the 5G Non-Standalone architecture is to add a 5G NR cell as a speed booster to an existing LTE radio and core network. It is different from … Continue reading 5G New Radio Q&A
Perhaps a bit of a strange title but I recently attended an event that had excellent LTE/5G coverage outside buildings, and good Wi-Fi coverage mainly inside buildings. In other words: A good opportunity to have a look at how well an ongoing IMS voice call is switched between LTE (VoLTE) and Wi-Fi (VoWifi) these days.
I’m on vacation at the moment and I’ve been thinking a bit about how network technology has evolved over the past few years and where we are headed. At least for the moment, it seems to be that we have reached an access network tech plateau, at least as far as infrastructure is concerned. Let … Continue reading An Access Network Plateau Reached?
As I’ve already noticed last year, there is quite a bit of packet loss over Starlink connections that has a significant impact on TCP performance. Also, I was wondering if and how much packet loss occurs in cellular networks during a handover. Recently, I picked up this topic again and was looking for a way … Continue reading Analyzing Packet Loss in Starlink
And yet another roaming story from my recent trip to North America: For voice and video calls to family and friends, I use my Prosody XMPP server in Germany, a voice stream reflector that is also located in the country and the ‘Conversations’ messenger app. By having all components close together, the speech path delay … Continue reading Roaming Report – Part 5 – Double Inter-Continental Voice Delay
After a bit of a disappointing prepaid eSIM (non-) experience directly from US network operators, I switched to plan B and had a look if I could get an eSIM for use in the US from one of the global eSIM roaming platforms. Two years ago, I checked out Airalo when I was roaming in … Continue reading Roaming Report – Part 3 – Airalo – 5 Minutes to the eSIM
It’s March 2024 and for the first time in 5 years (thank you Covid pandemic), I was in the US again. So far, so good, but there is one significant difference this time, at least from a technical point of view: For the first time ever, I’m roaming with Verizon! Most travelers won’t even notice, … Continue reading Roaming Report – Part 1 – Roaming with Verizon – A First!
Recently, I had a look if and how Android uses DNS over TLS (Transport Layer Security), i.e. encrypted DNS queries, and if this is actually configured automatically. It turns out that there is a simple yet nifty automatic procedure in place.
Back in December 2023 a number of interesting decisions were made at the World Radio Conference (WRC) in Dubai. One of the most important bands for which a number of decisions were made was the 6 GHz band. Today, spectrum in this band is already used for Wi-Fi, and it is pretty much the only … Continue reading Some Thoughts on the 6 GHz Band for Wi-Fi and Cellular