Pages

Thursday, 12 October 2017

3GPP Sidelink and its proposed extensions

In an earlier post I discussed briefly about the sidelink: V2V communications are based on D2D communications defined as part of ProSe services in Release 12 and Release 13 of the specification. As part of ProSe services, a new D2D interface (designated as PC5, also known as sidelink at the physical layer) was introduced and now as part of the V2V WI it has been enhanced for vehicular use cases, specifically addressing high speed (up to 250Kph) and high density (thousands of nodes).

Before going further, lets just quickly recap the different V2x abbreviations:

  • V2X = Vehicle-to-Everything
  • V2V = Vehicle-to-Vehicle
  • V2I = Vehicle-to-Infrastructure 
  • V2P = Vehicle-to-Pedestrian 
  • V2H = Vehicle-to-Home
  • eV2X = enhanced Vehicle-to-Everything

I came across this interesting presentation from ITRI that provides lot more details on sidelink and its proposed extension to other topics including eV2X and FeD2D (Further enhanced Device-to-Device).

There are quite a few references in the document that provides more details on sidelink and its operation and extension to other devices like wearables.


There are also details on synchronization and eV2X services.

There is also a very nice D2D overview presentation by Orange that I am embedding below (download from slideshare)



Saturday, 7 October 2017

2G / 3G Switch Off: A Tale of Two Worlds

Source: Wikipedia

2G/3G switch off is always a topic of discussion in most conferences. While many companies are putting their eggs in 4G & 5G baskets, 2G & 3G is not going away anytime soon.

Based on my observations and many discussions that I have had over the past few months, I see a pattern emerging.

In most developed nations, 2G will be switched off (or some operators may leave a very thin layer) followed by re-farming of 3G. Operators will switch off 3G at earliest possible opportunity as most users would have moved to 4G. Users that would not have moved to 4G would be forced to move operators or upgrade their devices. This scenario is still probably 6 - 10 years out.



As we all know that 5G will need capacity (and coverage) layer in sub-6GHz, the 3G frequencies will either be re-farmed to 4G or 5G as 2G is already being re-farmed to 4G. Some operators may choose to re-balance the usage with some lower frequencies exchanged to be used for 5G (subject to enough bandwidth being available).


On the other hand, in the developing and less-developed nations, 3G will generally be switched off before 2G. The main reason being that there are still a lot of feature phone users that rely on 2G technologies. Most, if not all, 3G phones support 2G so the existing 3G users will be forced onto 2G. Those who can afford, will upgrade to newer smartphones while those who cant will have to grudgingly use 2G or change operators (not all operators in a country will do this at the same time).

Many operators in the developing countries believe that GSM will be around until 2030. While it may be difficult to predict that far in advance, I am inclined to believe this.

For anyone interested, here is a document listing 2G/3G switch off dates that have been publicly announced by the operators.



Let me know what you think.

Further reading: