Wednesday, 28 May 2014

Case Study: RAN Sharing in Poland

The last post on Network sharing by NEC was surprisingly popular so I thought its worth doing a case study by Orange in Poland on how they successfully managed to share their network with T-Mobile. Full presentation embedded as follows:

Wednesday, 21 May 2014

Connected and Autonomous Car Revolution

Last week we had the Automotive and Transport SIG event in Cambridge Wireless. There is already some good writeup on that event here and here. In this post my interest in looking at the technologies discussed.

R&S (who were the sponsors) gave their introduction presentation quite well highlighting the need and approaches for the connected car. He also introduced the IEEE 802.11p to the group.

As per Wikipedia, "IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE), a vehicular communication system. It defines enhancements to 802.11 (the basis of products marketed as Wi-Fi) required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). IEEE 1609 is a higher layer standard based on the IEEE 802.11p."

Back in December, Dr. Paul Martin did an equally useful presentation in the Mobile Broadband SIG and his presentation is equally relevant here as he introduced the different terms live V2X, V2i, V2V, V2P, etc. I have embedded his presentation below:

Roger Lanctot from Strategy Analytics, gave us some interesting facts and figures. Being based in the US, he was able to give us the view of both US as well as Europe. According to him, “LTE is the greatest source of change in value proposition and user experience for the customer and car maker. Bluetooth, Wi-Fi, NFC and satellite connectivity are all playing a role, but LTE deployment is the biggest wave sweeping the connected car, creating opportunities for new technologies and applications.” His officially released presentation is embedded below (which is much smaller than his presentation on that day.

There were also interesting presentations that I have not embedded but other may find useful. One was from Mike Short, VP of Telefonica and the other was from Dr. Ireri Ibarra of MIRA.

The final presentation by Martin Green of Visteon highlighted some interesting discussions regarding handovers that may be required when the vehicle (and the passengers inside) is moving between different access networks. I for one believe that this will not be an issue as there may be ways to work the priorities of access networks out. Anyway, his presentation included some useful nuggets and its embedded below:

Saturday, 17 May 2014

NFV and SDN - Evolution Themes and Timelines

We recently held our first Virtual Networks SIG event in Cambridge Wireless. There were some great presentations. The one by the UK operator EE summarised everything quite well. For those who are not familiar with what NFV and SDN is, I would recommend watching the video on my earlier post here.

One of the term that keeps being thrown around is 'Orchestration'. While I think I understand what it means, there is no easy way to explain it. Here are some things I found on the web that may explain it:
Orchestration means Automation, Provisioning, Coordination and Management of Physical and Virtual resources.  
Intelligent service orchestration primarily involves the principles of SDN whereby switches, routers and applications at Layer 7 can be programmed from a centralized component called the controller with intelligent decisions regarding individual flow routing in real time.
If you can provide a better definition, please do so.
There are quite a few functions and services that can be virtualised and there are some ambitious timelines.

ETSI has been working on NFV and as I recently found out (see tweet below) there may be some 3GPP standardisation activity starting soon.
Anyway, here is the complete presentation by EE:

There was another brilliant presentation by Huawei but the substance was more in the talk, rather than the slides. The slides are here in case you want to see and download.

Related post:

Monday, 12 May 2014

Improvement in Interference Rejection and Suppression Technology

In the last post where I talked about FeICIC I mentioned about the advanced Interference rejecting receivers, here is one very good article from NTT Docomo technical journal. The following is from this article:

Rel. 11 LTE has introduced MMSE-Interference Rejection Combining (MMSE-IRC) receivers as a mobile terminal interference rejection and suppression technology to mitigate the effects of these interference signals and increase user throughput even in areas that are recently experiencing high interference. Rel. 8 LTE receivers support MIMO transmission technology, so receivers were equipped with at least two antennas since it was first introduced. The MMSE-IRC receivers in Rel. 11 LTE, are able to use the multiple receiver antennas to create points, in the arrival direction of the interference signal, where the antenna gain drops (“nulls”) and use them to suppress the interference signal (Figure 1). The terminal orients a null toward the main interference signal, which is the signal that particularly affects the degradation of throughput, thereby improving the Signal-to-Interferenceplus-Noise power Ratio (SINR) and improving throughput performance.

However, with the original MIMO multiplexed transmission, which realized high throughput using multiple transmit and receiver antennas, the receiver antennas are used to separate the signals between layers, so interference from adjacent cells cannot be suppressed and throughput cannot be improved, particularly for mobile terminals with two receiver antennas.

On the other hand, the 3GPP has already included interference rejection and suppression technology in performance specifications for mobile terminals equipped with W-CDMA/High-Speed Downlink Packet Access (HSDPA) in Rel. 7 of the Universal Mobile Telecommunications System (UMTS). With W-CDMA, receivers normally use one receiver antenna and perform Rake reception, but the effects of multipath interference degrading reception performance was an issue.

Thus, the following three receiver extensions were studied and introduced.
• Type 1/1i extends the Rake receiver to use two antennas.
• Type 2/2i extends the Rake receiver to an MMSE receiver that suppresses multipath and adjacent-cell interference.
• Type 3/3i extends the MMSE interference-suppressing receiver defined in Type 2/2i to use two receiver antennas.

The functional extensions in receivers in Rel.7 UMTS and Rel. 11 LTE are summarized in Table 1. The MMSE-IRC receivers in Rel. 11 LTE incorporate receiver algorithms that are generally equivalent to those in the Type 3/3i receivers introduced in WCDMA/HSDPA. However, in the WCDMA/HSDPA receivers they also operate to suppress inter-coding interference within a cell. There is no interference within a cell in LTE systems, so in the MMSE-IRC receivers introduced in Rel. 11 LTE, they operate to suppress interference arriving from adjacent cells.

From my understanding, a similar approach is being proposed for the Mobile Relay Node (MRN)

Anyway, the complete article is as follows:

Monday, 5 May 2014

WebRTC (Web Real-Time Communication) Updates

Its been a while since I last blogged about WebRTC. Things have been progressing as rather fast pace in this area.

WebRTC capabilities have quietly sneaked in our browsers. There is a debate about who would move to WebRTC before, Apple or Microssoft; Tsahi Levent-Levi makes his predictions here.

As per Light Reading, Japanese operator NTT has opened a WebRTC based chatroom recently.

The Korean operator SK Telecom as been showing off its WebRTC interworking with IMS platform.

The problem with WebRTC can be as seen in the slide above. Classic problem of what was promised and whats the reality.

There are 2 interesting presentations that I am embedding below that I found useful:

Additional Reading:

Thursday, 1 May 2014

Further enhanced Inter-Cell Interference Coordination (FeICIC)

Recently while delivering a training, I realised that this is a topic that I haven't covered in the blog before, even though I have been talking about it for a while. FeICIC has been introduced in Release-11 and there are a few enhancements as shown above. The main being that instead of an Almost Blank Subframe (ABS) with no other information except for the reference signals, now there is a possibility of reduced power ABS where the data on PDSCH can still be transmitted but on a reduced power level. This would ensure that the capacity of the interferer is not wasted.

Another enhancement on which FeICIC depends on are the advanced receivers (should do a post on it sometime soon). Another feature that allows a better probability of reception is the Transmission Mode 9 (TM9 - see blog post here)

An interesting comment that I received on my Deployments Dilemma Post is also relevant to the discussion here:

The ground reality is generally a lot different than theory. Metrocells often face interference not just from Macrocells but also other Metrocells. The ABS patterns are not just straightforward Macro to pico case but even pico to pico and multiple macros to pico.
Until all the handsets and other dongles could be upgraded with advanced interference cancellation receivers, there would be many scenarios where deployment option 2 may be chaotic. Deployment option 1 can serve the users well in the meantime. 
We can sacrifice efficiency for reliability in the meantime.

I recently posted the Small Cells Research Bible on the Small Cells blog here, the following is the Interference Management part that would help anyone willing to learn more about this feature.