Qualcomm, as you will no doubt know, has had the device chipset market tied down about as much as is possible in a global market. Yet the vendor is also working hard to turn its top end device know-how into design wins in small cell technology – notching up a number of scores with small cell vendors such as ip.access, Alcatel-Lucent and Cisco.
Additionally if operators want to offer higher bandwidths and capacities by aggregating frequencies, they are going to need devices capable of handling that: and that’s not as simple as it sounds.
Here, Laurent Fournier, head of Global Business Operations for Qualcomm in Europe, outlines how Qualcomm sees small cells as a drop-and-fit solution for adding capacity to networks within the same frequency bands as macricells.
He also calls out the complexity required to support carrier aggregation at the device level, and identifies a couple of key technologies of potential benefit to operators.
Too long, didn’t read summary:
1. Small cells – instead of obsessing over perfect placement and backhaul availability, get them deployed in large numbers as best you can and use technology such as cell ranging and FeICIC/IC to sort out interference and make sure performance is unaffected for both macro and small cells. Small cells can also be backhauled over heavily-optimised LTE TDD links.
2. Carrier Aggregation is easier for the operators and equipment vendors who need to support only 2-3 combinations. Devices must support a host of multiple potential combinations. The complexity is with the chip developers, then, who must deliver solutions to OEMs that require the fewest possible “skews” to implement.
3. RF360 programme: power shaping [envelope tracking[, antenna tuning and passive element consolidation will reduce the size of occupation in the device of these elements by 50%. Matters because? Will let devices do more.
4. LTE Direct: device-to-device local discover-ability that is low power, low interference and can offer good potential for contextual or local services. Users can control which “broadcast” messages they receive from other users. Deutsche Telekom has Qualcomm’s SDK and is playing with certain use cases.
SMALL CELLS:
The good thing is that LTE prepared itself for small cells, by allowing effectively the small cells to co-work in a macrocell environment leveraging the same frequencies and not jeopardising the capacity of the macro or small cell, so we were quite innovative in that respect.
We also try to serve other types of interest from the operators, reducing the cell size, the price of a small cell by putting it more in the vicinity of a high tier smart phone, making it easy plug in to the fixed connectivity that you have.
The idea is to have equipment that can easily radiate from indoor to outdoor, optimising itself with other small cells and the macro layer. That’s much more useful for an operator than figuring out exactly where traffic is, making sure you find the exact hotspot location, getting backhaul to that location etc.
In that model, if you have not been able to negotiate the right spot then you’ve somehow missed your investment. Whereas with small cell advances you can almost randomly spread a certain amount of low cost small cells and maximise the capability to capture the hotspot traffic you were looking for. On top of that if you add LTE improvements like Cell Ranging [Range Expansion through FeICIC/IC] using the ability to properly set power levels to co-ordinate with the macrocell layer, then you are maximising the reach of a small cell under a macro layer by allowing good cell edge performance for a device that is connected quite distantly from the small cell.
So that’s the concept – something very innovative and easy to install for the operator.
Who integrates the SON in the small cell – Qualcomm or the vendor?
That really depends on the model the manufacturer wants to leverage. Either he goes for pure L1 minimum connectivity and does the job of implementing his own SON solution, or we have the capability to provide our UltraSON suite of solutions that he can build upon.
Communication to the gateway, OAM mechanisms, and so on can remain proprietary from the vendor.
Qualcomms is in Cisco, ip.access is using our entire suite of solutions, Alcatel-Lucent will have its first equipment in the second half of this year once our chipset is commercially available.
Small Cell Backhaul
We have solutions that allow carriers to leverage 2.6 GHz TDD as backhaul to a small cell. We further enhance that by cleaning up the signalling to really maximise the bandwidth that you can get out of LTE in TDD mode. The bit rate in 20MHz of 2.6 GHz TDD is bigger than what is normally advertised for a mobile. It definitely helps to simplify the installation of small cells. [Editor’s note: Via its acquisition of Israeli chip company DesignArt, Qualcomm is “inside” several NLOS small cell backhaul products from the likes of Fastback Networks and others]
Carrier Aggregation – the device wears the complexity:
The first step is to achieve two carrier aggregation (CA) delivery. There is complexity around CA that one can not exclude. A carrier or infrastructure vendor, when they are delivering CA they have to aggregate just two frequencies for one operator. A device platform, when it is delivered to the OEM, has to be capable of supporting a whole bunch of CA types, so the complexity is on our side rather than the infrastructure side.
The number of bands we have to aggregate means we must limit the number of skews the OEM would have to develop for a Cat 6 device, making the appropriate device across all the infra vendors we have in front of us and testing all these combinations in real networks.
To ensure the whole IOT works properly, roaming conditions, mobility conditions, a device will need to be able to work from one type of CA installed by the operator, and which has to provide continuity with another CA mode installed by the same operators, and all these cases we need to be able to put in place. The message is the complexity of adding another band, from two to three Carrier Aggregation is not the major hurdle.
The major hurdle is to ensure all types of combinations we have to cope with are efficiently working between ubiquitous and mobility modes. So basically the burden is on our shoulders.
RECEIVE DIVERSITY:
Receive diversity is an important element, we are working on providing more receive diversity schemes, to three and potentially four. You need two well engineered antennas, that’s the minimum gain you need, the third and fourth antenna may not be that exceptionally engineered but you can still play with that. In a device you have GPS and WiFi antennas, so why not try to use those extra antennas to provide three receive diversity or four receive diversity to the mobile? It’s forward-looking for the moment but something we talk about because we think it’s a sensible way to go to improve the quality of reception to our devices.
In many cases the antennas are set on the edge of the device so when you grab the device, in the palm of your hand, you may hide at least one antenna and then those 3rd and 4th antenna techniques will also be of relevance.
RF360 PROGRESSION
In envelope tracking – optimising the voltage you provide to the Power Amplifier (PA) when it needs to transmit at a certain power level – we have more than 50 design wins already in 15 OEMs. In antenna tuning we are implementing already: the Lumia520 is leveraging that particular technology.
The third element of RF360 is instead of having a whole bunch of passive elements (PEs) such as independent filters and PAs addressing all the different frequencies, what we are proposing is to be able to aggregate all these elements using CMOS technologies into a smaller piece of equipment.
And we will go one step further to offer the possibility for any vendor or OEM to aggregate antenna tuning, envelope tracking, passive element aggregation into one chip. That reduces the equivalent size of occupation of all these elements by 50%. So it’s additional space provided to the OEM.
That performance allows you to very quickly reach more than 1,000 devices in this range with minimum battery consumption, generating a very controlled level of interference
LTE DIRECT:
You can compare it to WiFi Direct in terms of concept except it’s much more powerful than WiFi Direct, with ultra low power consumption and ultra fast in terms of latency, allowing you a range of 500m depending on propagation conditions.
That performance allows you to very quickly reach more than 1,000 devices in this range with minimum battery consumption, generating a very controlled level of interference. And you are not affecting the capacity of the network, using just 0.3% of the 5MHz assigned to discovery mode, so it is super efficient.
It allows you effectively to broadcast very short information and regularly listening to other broadcasts to discover other devices in a certain range. Once discovered, devices have the ability to exchange parameters which you would have set as a user, as a set of preferences. Just because you are discovering all devices does not mean you are interested in all their characters, so you can filter the info sent by others in broadcast mode. As a receiver you can say you are interested in certain sequences and not in others.
DT made an announcement that they are entering a phase of testing and developing use cases, so we have provided an SDK to them which allows them to play with our mobile test platforms and start developing the use cases that could be relevant to them.
