HetNets On The Bus

Earlier in March, I helped organise 'The Gigabit Train' seminar'. The intention was to look at the connectivity options inside the trains and its monetisation. While connectivity in the trains is challenging, thinking back about it, due to a predictable route it can be sometimes easy to deploy. It could be more of a challenge for cars and buses that go through unpredictable routes and conditions.

I also discussed the "Vehicular CrowdCell" or "Vehicular Small Cell" concept here to look at some advantages of such a solution option.

Some of you may be aware that I recently joined Parallel Wireless. We were selected by M1 Limited, Singapore’s most vibrant and dynamic communications company, to support its WiFi-On-The-Go service as a part of the HetNet trial.

This is the architecture of the On-Bus Hetnet. Some of you would find it self-explanatory.

The mobile operators in Singapore are looking for innovative technologies to address spectrum scarcity as subscriber demand is growing rapidly with smartphone penetration reaching 130 devices per 100 people. Maximizing utilization of the spectrum and easing network congestion in areas with heavy human traffic is necessary to meet Infocomm Development Authority of Singapore (iDA) vision of connecting the whole nation as a part of world’s-first Smart Nation initiative.

Real-time HetNet orchestration and traffic prioritization is made possible by HetNet Gateway (HNG). All bus riders receive seamless, high throughput connectivity from an on-bus multi-mode LTE/Wi-Fi Converged Wireless System (CWS) small cell with integrated backhaul including licensed assisted backhaul.  By enabling carrier aggregation for backhaul, the end user throughput can be increased 10 times (up to 300 Mbps) allowing transit passengers to enjoy multimedia content without buffering.

Here is a presentation that gives the complete story:

Some questions on this demo from Linkedin:

Q: Does seamless handover are available with no drop in data throughput through out the travel route of Bus? 
A: Yes, handover is seamless, no dropped data or voice calls. This was one of the iDA trial requirements. We can do seamless VoLTE to VoWiFi handover and back.

Q: What is the maximum data rates does the system accommodate for all seamless data transfers? Does the system support motion video play from N/W. If so of what bandwidth and data rates? 4. How many users does the system support and what data rates?
A: It will depend on the backhaul. We can increase backhaul capacity with CA on 4G + to 300 Mbps shared bandwidth.

Q: This seems to be a relay device ( a femto or pico grade small cell with UE backhaul). an their innovative hetnet gateway for traffic engineering ( LBS support ). 
A: Our in-vehicle unit is a Small cell (LTE/Wi-Fi for access) with any backhaul incl UE backhaul. The HetNet Gateway, in addition to performing 3G, 4G, WI-Fi gateway functionality and real-time SON with ICIC, will also do the traffic engineering.

And demo from inside the bus:


Further reading:

• Parallel Wireless Selected by M1 to Support Smart Nation Trial

"Vehicular CrowdCell" or "Vehicular Small Cell" and the 5G plan

In the recent Mobile World Congress, Vodafone and BMW introduced the Vehicular CrowdCell concept, a small cell providing coverage in the car when people are in it and outside when the car is parked. The presentation is embedded later on in the post.

The following is from the BMW press release:

...the BMW Group is unveiling the research project “Vehicular CrowdCell”. This project extends the concept of the “Vehicular Small Cell” presented last year in Barcelona. While the “Vehicular Small Cell” is a mobile femtocell that optimises the mobile radio reception inside vehicles, it is now also capable to enhance the capacity and coverage of mobile radio networks. The BMW Group is teaming up with peiker and Nash Technologies to present a prototype of the “Vehicular CrowdCell” integrated into a BMW research vehicle.

The rapid growth of mobile data traffic, e.g. due to the increasing use of multi-media services such as music or video streaming with mobile devices, requires even more powerful mobile radio networks in the future. One strategy to increase the capacity and coverage of future networks is the integration of a large number of small cells and relays in addition to the existing base stations.

In 2015 the BMW Group, together with its partners peiker and Nash Technologies, presented the world’s first mobile femtocell in a vehicle. The “Vehicular Small Cell” optimises the reception available to mobile devices inside vehicles via the vehicle’s aerial. Now the concept has been extended to create the “Vehicular CrowdCell”. Based on data traffic and coverage demands, the mobile femtocells are dynamically activated to locally enhance mobile radio networks.

The benefits of Vehicular CrowdCells in practice.
One possible application of “Vehicular CrowdCells” are car-sharing fleets – in particular with electric vehicles. Here, a large number of vehicles spread over cities and regions could serve as local radio relays when parked. If one or more users are located close to a mobile femtocell, it is activated on demand in order to increase the bandwidth or provide additional network coverage. In such a way, the performance of the existing network can be dynamically optimized. Benefits for mobile phone users in hotspots include a higher data rate and the absence of reception white spots – especially in areas where the signal coverage is low.

“The “Vehicular Small Cell” will optimise in-vehicle connectivity of mobile devices for our customers,” explains Dr. Peter Fertl, project manager at the BMW Group. “At the same time, the integration into a network of “Vehicular CrowdCells” will enable the ubiquitous and seamless availability of high-quality mobile radio connections outside the vehicle as well.”

Nash innovations have more details about the earlier version of this, The "Vehicular Small Cell" here and here.

Before we go any further, check out the Vodafone presentation embedded below:

I wrote a blog on this topic back in May 2014 here. In that article I mentioned that for a small cell in the car, the biggest challenge is backhaul. One approach is to use one particular frequency for backhauling to the small cell and then the small cells output another frequency. This approach was mentioned in another blog post here. In this approach, TD-LTE was used for backhaul and it created an FDD LTE small cell inside the train.

Why do I think this kind of approach work with 5G. In my other post about 5G spectrum, I mentioned that 5G will need multiple frequencies. Low frequencies for coverage, high frequencies for capacity and very high frequencies for very high speed throughput's. Because the very high frequencies, do not travel very far as compared to the low frequencies (with the same power), beamforming would be used. These very high frequency beams can be directed towards the Vehicular small cells, which in turn would create a much larger cell at a lower frequency.

This approach would typically only be used in urban environments as in rural areas there is plenty of unused spectrum (until more uses are found - quite possible with the IoT device explosion). The small cells would also need advanced sensing and SON capability to work in harmony with the macro network.

If you have an opinion, feel free to add it in the comments section.

Small Cells for the 'Connected Car'

Couple of weeks back I was in an event where Connected cars were a big focus. A few discussions centred around Small Cells in the cars. It may be a bit of a challenge but it should still be possible to have Small cells in the cars. The biggest challenge would be the backhaul. You cant have the standard backhaul for cars, especially as its moving, generally at high speeds. 

Some tricky solutions where one of the frequencies is used for backhauling small cells while small cells would provide coverage to the passengers of the car may be doable but it may not be worth the effort. 

Generally, the focus right now is to have something like a MiFi device in the car. The device can receive the mobile network signals and create a Wi-Fi hotspot.

Another solution being discussed was the use of Mobile Relay Node (MRN). As far as I understand, MRN has been pushed out of Release-12. Another issue is that the practical gain may not be as good as expected. Most of all, small cells or relay would only be useful if all the passengers in the vehicle reply on the same mobile network operator. As far as I have seen, this is generally not the case.

In light of this, it would make sense to continue on the current solution of having Wi-Fi hotspots in the cars backhauled to the mobile network.

Your thoughts please.