LTE Focus, 2010

- report on the LTE Focus Conference held in Amsterdam on 9th Sept 2010 detailing the main themes and technology trends.

The LTE Focus conference was held at the Radission Blu Hotel just out side Schipol Airport at Amsterdam. With easy travel, it was possible to make it there and back in a day.

The LTE Focus conference has an impressive line-up of speaker, all with very practically useful titles.

With LTE deployments now a reality, as one speaker mentioned: "LTE has moved from the 'what' and 'if', to the 'how' and 'when'." While there are already three live LTE networks (at the time of the conference) - Norway, Sweden and Uzbekistan - there are still some major issues to be resolved if LTE and also cellular technology is to continue to grow as expected. Some of these issues may be controversial, but they were raised and discussed, making the time at LTE Focus particularly useful.

LTE Focus themes

As with many conferences, LTE Focus produced a number of themes that each resonated through several of the presentations. It was often these themes which showed the expectations for the LTE and also the issues that were becoming apparent, and that different organisations were addressing. Possibly there were six main issues that came out of LTE Focus this time, although there was plenty more to digest.

1. Data explosion
2. Data offload
3. Cell sizes
4. Multiple RATs
5. Spectrum issues
6. Testing

Although all the topics mentioned above were mentioned by several speakers, many other important issues were raised by individuals within different LTE Focus presentations.

Data explosion

The idea of the data explosion that will take place was evident right from the first presentation at the LTE Focus conference. Graphs showing the way in which data growth will occur abounded. Figures of 30 fold increases in data traffic over the next five years were quoted - although revenues would only increase three fold. These would come from a number of sources:

• M2M - there will be a significant increase in machine to machine usage. With LTE being an "all IP" network, always on capabilities are there and it is anticipated that there will be a very large number of low data rate devices connected such as health monitors, etc, although applications such as live video monitoring could take significant bandwidth.
• Increased use of high end phones - new phones with many features are expected to take up far more bandwidth. Smartphones such as the iPhone and many other similar phones are being used. These are very bandwidth hungry as the APPs have a heartbeat which needs to be accommodated. Although not real data as such, it still uses network bandwidth and operators are seeing increased data usage as a result.
• Video - The sue of video over the network is expected to grow very rapidly, with many projections showing this to be largest user of bandwidth.
• Mobile broadband - users in some areas are now using the cellular infrastructure to provide their Internet connection. In fact it is anticipated that before long, mobile Internet will be the norm. Also there is an LTE trial in Cornwall that will provide broadband for cable / DSL deadspots.

This data explosion not only needs to be accommodated by the operators, but phone designs also need to be able to handle the large amounts of data.

Data offload

With the explosion in the use of data, capacity needs to be put in place by the operators ahead of the explosion. While straight capacity is one method, other ways of achieving this are also needed otherwise costs will rise too far.

As over 50% of mobile data usage is from within buildings, offloading to the broadband connections are one particularly cost effective method.

There are two ways that are being used:

• UMA - using the Wi-Fi link present in most homes to offload the data traffic from the main cellular network. However as one person mentioned, many users turn off their Wi-Fi to preserve battery life.
• Picocells - the idea of using home or office picocells using the Internet connection to provide the backhaul has many advantages. The idea is now starting to grow and although there are some issues, these appear to be in the process of being resolved.

Cell sizes

It was mentioned that although there had been significant improvements in the efficiency of the new cellular systems from GSM through GPRS, EDGE ... LTE, the main improvements in capacity have been brought about by using progressively smaller cells. To this end, the future developments of femtocells for business as well as metropolitan and rural areas will enable more base-stations to be installed at very low cost.

Multiple RATs

Since the launch of GSM there has been a proliferation of standards as cellular technology has evolved. These successive evolutions have generally been preserved and there has been no switch-off as in the case of the analogue systems, although US Digital (also called TDMA) has been discontinued. However GPRS, EDGE, WCDMA, HSPA and now LTE are all active. Phones need to support these in order to ensure that they are able to provide the service regardless of their location.

This provides problems for the handset designer who has to incorporate all these standards into one handset or user equipment. This then reflects into the silicon designer. Whether this is addressed in software or in hardware as dedicated silicon areas within a chip. While there are advantages for both approaches, those presenters at the LTE Focus conference tended to advocate the software approach for the longer term.

Spectral issues

It was accepted that one of the successes of GSM and then WCDMA was the fact that the spectral allocations were almost the same worldwide. Not only did this bring significant economies of scale, but it brought large levels of trust on the system which could be used in almost anywhere around the globe.

Currently spectral issues around the globe mean that the spectrum allocations for LTE are very fragmented around the world. While it is difficult to provide universal allocations, the spectrum for LTE is now so divided that it could threaten the deployment and uptake of LTE.

LTE testing

One of the areas that has been particularly successful for GSM and then for UMTS has been the adoption conformance testing. However with the newer technologies such as HSPA and now LTE, new testing regimes are needed. With the introduction of much more complicated protocols along with RF technologies including OFDM and MIMO, the older testing regimes provided by conformance testing - looking at different elements at a time, may not provide the rigorous levels of testing of combined features that may be needed.

Scenarios using real life and simulated scenarios with multiple actions as well as end to end testing were proposed as the solution because these would not only combine different elements of the system but would also look at the operation under more realistic conditions.

Femocells

The conference finished with an additional evening workshop or seminar provided by picoChip entitled Deploying small cell architectures for LTE. It provided a significant amount of information about LTE femtocells from the basic 'physics' through the principles of self-optimising networks to handover issues and interference.

This was of particular interest to many as femtocell technology forms an integral part of LTE deployment.

LTE Focus Summary

The success of LTE Focus is bound to ensure the future of the event. It is worth remembering to check back at the LTE Focus website where you can also buy the downloadable copy of the proceedings.