Telefonica UK London Small Cells (Wi-Fi, 3G, 4G)

From a presentation by Robert Joyce, Chief Radio Engineer, Telefonica UK in the 3G, HSPA, LTE Optimisation conference.

LTE 'Antenna Ports' and their Physical mapping

People who work with LTE Physical layer and maybe higher layers would be aware of this term called 'Antenna Ports'. I have always wondered how these antenna ports are mapped to physical antennas.

The following is from R&S whitepaper:

The 3GPP TS 36.211 LTE standard defines antenna ports for the downlink. An antenna port is generally used as a generic term for signal transmission under identical channel conditions. For each LTE operating mode in the downlink direction for which an independent channel is assumed (e.g. SISO vs. MIMO), a separate logical antenna port is defined. LTE symbols that are transmitted via identical antenna ports are subject to the same channel conditions. In order to determine the characteristic channel for an antenna port, a UE must carry out a separate channel estimation for each antenna port. Separate reference signals (pilot signals) that are suitable for estimating the respective channel are defined in the LTE standard for each antenna port. 

Here is my table that I have adapted from the whitepaper and expanded. 

The way in which these logical antenna ports are assigned to the physical transmit antennas of a base station is up to the base station, and can vary between base stations of the same type (because of different operating conditions) and also between base stations from different manufacturers. The base station does not explicitly notify the UE of the mapping that has been carried out, rather the UE must take this into account automatically during demodulation (FIG 2).

If there is another way to show this physical mappings, please feel free to let me know.

The R&S Whitepaper is available here if interested.

'License-exempt' bands in the UK

10 Times Beyond LTE-A (5G maybe?)

Recently when I added a presentation by NSN on whats coming after IMT-Advanced, it was very well received and has already had over 8000 views. There seems to be definitely an appetite for the future networks. Here is another such presentation.

10 Times Beyond LTE-A

View more presentations from Zahid Ghadialy

There is also a video of the presentation if you have the patience to sit, watch and learn.

3 Stages for Seamless Mobility between 3G and WLAN

Evolution of Machine Type Communications (MTC)

RAN Release 11 Priorities

Signalling Load per device and OS

From the presentation by Martin Prosek, Telefonica, Czech Republic in 3G Optimization Conference 2012, Prague.

Signalling can cause many issues:

In the mobile device, Frequent PDP-context establishment is known to drain the battery. Battery life can be improved by supporting fast dormancy in network.

In the network, Signalling flood can create situations reminding DoS attacks. Increased signalling in RAN can cause impacts in core network:

• Radius/Diameter interface overload of AAA servers
• DHCP IP address pools exhaustion

New Spectrum for LTE-Advanced Carrier Aggregation

LTE and IPv6

A discussion on Linkedin prompted me to add some relevant documents relating to LTE and IPv6. Interesting presentation below by Cisco:

Designing LTE with IPv6

View more presentations from Zahid Ghadialy. Available to download from slideshare here.

There are some other interesting presentations on slideshare you may want to look at:

• Embracing IPv6 - part of the Joint GSMA/NGMN Conference Stream “Technology Evolution”
• Advances in IPv6 Mobile Access - John Loughney,Nokia
• IEEE Globecom 2010: Mobile Communication and IPv6 - John Loughney,Nokia
• T-Mobile USA IPv6 Deployment