Showing posts with label Synchronization. Show all posts
Showing posts with label Synchronization. Show all posts

Thursday, 19 July 2018

5G Synchronisation Requirements

5G will probably introduce tighter synchronization requirements than LTE. A recent presentation from Ericsson provides more details.

In frequencies below 6GHz (referred to as frequency range 1 or FR1 in standards), there is a probability to use both FDD and TDD bands, especially in case of re-farming of existing bands. In frequencies above 6GHz (referred to as frequency range 2 or FR2 in standards, even though FR2 starts from 24.25 GHz), it is expected that all bands would be TDD.

Interesting to see that the cell phase synchronization accuracy measured at BS antenna connectors is specified to be better than 3 μs in 3GPP TS 38 133. This translates into a network-wide requirements of +/-1.5 microseconds and is applicable to both FR1 and FR2, regardless of the cell size.

Frequency Error for NR specified in 3GPP TS 38.104 states that the base station (BS) shall be accurate to within the following accuracy range observed over 1 ms:
Wide Area BS → ±0.05 ppm
Medium Range BS → ±0.1 ppm
Local Area BS → ±0.1 ppm

The presentation specifies that based on request by some operators, studies in ITU-T on the feasibility of solutions targeting end-to-end time synchronization requirements on the order of +/-100 ns to +/-300 ns

There is also a challenge of how the sync information is transported within the network. The conclusion is that while the current LTE sync requirements would work in the short term, new solutions would be required in the longer term.

If this is an area of interest, you will also enjoy watching CW Heritage SIG talk by Prof. Andy Sutton, "The history of synchronisation in digital cellular networks". Its available here.

Thursday, 12 April 2018

#CWHeritage Talk: The history of synchronisation in digital cellular networks

CW (a.k.a. Cambridge Wireless) held a very interesting event titled 'Time for Telecoms' at the Science Museum in London. I managed to record this one talk by Prof. Andy Sutton, who has also kindly shared slides and some other papers that he mentions in his presentation. You can also see the tweets from the event on Twitter.

The video playlist and the presentation is embedded below.

The papers referred to in the presentation/video available as follows: