3GPP is putting a lot of meat on the bones these days to the 5G New Radio (NR) study item. In the recent edition of TS 38.801 (Study on New Radio Access Technology) I read that the base station in 5G New Radio (NR) will be referred to as gNB. Unfortunately it is not mentioned what the ‘g’ actually stands for!?
Back in 2014 I had a peak experience in global roaming. LTE was becoming available everywhere I went across the globe, my smartphone supported most LTE bands in Europe, the US and Asia and my mobile network operator of choice started a global roaming offer. While the roaming offer ‘only’ includes 150 MB for a week for around 12 Euros (infinitely re-bookable) it has made me independent of crappy Wifi connectivity at hotels and meeting venues and of the hassle organizing a local SIM card. Unfortunately since that time my operator had to make a few exceptions to that global data roaming offer and Vietnam, the country I recently visited was unfortunately among them. At 80 cents per 50 kbytes of data, switching mobile data on even only for checking emails was absolutely out of the question.
In an earlier post I had a a look at the different options for Cellular IoT (NB-IoT) when it comes to connectivity. One of the options is to use the cellular control plane to forward the raw data without wrapping it into IP data packets (NIDD, Non-IP data delivery). At the time I wondered a bit whether that would be a good idea. But perhaps it actually is!?
The LTE air interface uses Orthogonal Frequency Division Multiplexing (OFDM) to transmit many slow data streams (1200 in a 20 MHz carrier) in parallel to achieve a very high overall speed. OFDM is not exclusive to LTE, it is used in many other systems such as Wifi and DSL as well. For more details have a look at this post from back in 2007. One thing not contained in that earlier post is how each of the 1200 slow data streams is actually transmitted. In good signal conditions 64QAM is used in the LTE downlink direction. So what is 64QAM and how does it work? Continue reading An Introduction to QAM Modulation for LTE
When I was recently in China, it was an ideal opportunity to have a look at the ratio of downlink and uplink timeslots in a real network. The standard is quite flexible in this regard and offers many options so I was not quite sure which option would actually be used in practice. Continue reading TD-LTE – Number of Uplink Timeslots Observed in Practice
It’s been a while since I read a good techno-thriller with a believable plot from an author that gets the technology right. William Hern’s Chronos is a book I enjoyed and so was The Billion Dollar Heist by Ben Lovejoy and Marc Russinovich’s novels like Rouge Code are also great examples. Now I’ve found another author and book that falls into this category, Andrew Diamond with his latest book Impala.
In a previous post I’ve looked at 3GPP band 46, the band number assigned in 3GPP Release 13 to the 5 GHz band currently mostly used by Wifi only. So how pristine is this beachfront property today? Let’s have a look at my place in Cologne and compare it with use of the 2.4 GHz band.
License Assisted Access (LAA) is the term in 3GPP to potentially use the 5 GHz band, which is mostly used by Wifi networks today for LTE in the future. It looks like 3GPP has made a jump forward on the topic as the band has received a 3GPP band number in TS 36.101. It’s already in 3GPP Release 13 but a number of extensions in 3GPP Release 14 make it a special kicker.
Last year I had a great time reading ‘The Innovators’ by Walter Isaacson, a wonderful book that spans computing history from Charles Babbage and Ada Lovelace to our days. There are a lot of stories inside the book and each can only be a short summary of events. That’s why I also enjoy reading books about particular parts of computing history, and ‘Dealers of Lightning’ by Michael Hiltzik on the history of personal computing at Xerox PARC is just one of those.
Recently, T-Mobile US has announced that they have switched on 4×4 MIMO support in their network and first smartphones are now supporting 4 simultaneous downlink streams. Quite an interesting announcement as most antennas and base station sites currently deployed by most operators do not yet support this. So let’s have a look at what has changed in recent years in base station technology.