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Tuesday, 8 October 2013

Super Macros and HetNets

The other day I read the following on Light Reading:

UK operator EE wants to turn its existing macro cell sites into "super macros," according to Andy Sutton, the carrier's principal network architect, speaking at the recent Base Station conference in London.

EE 's plan to super size its macro cell sites fits in to a broader Heterogeneous Network (HetNet) strategy for adding capacity and extending coverage. The operator rolled out the first LTE network in the UK last year, and has now covered 55 percent of the UK population and has 1 million 4G customers.

"Super macro is the first step toward building a HetNet,” said Sutton. “Evolving the macro is the most cost-optimized way to adding capacity into our networks."

But what makes a macro super?

According to Sutton, a super macro would typically have multiple radio access technologies (RAT), three-to-six base station sectors, and operate in multiple frequency bands using carrier aggregation techniques. It could be a standalone base station or a hub for subtended, smaller micro cells. He added that infrastructure sharing is vital to the strategy as well.

Once the operator has sufficiently beefed up its macro cell sites, then it can look to smaller cells to be deployed indoors and outdoors in hotspots or cell edge locations. Sutton described a small cell deployment as an "underlay" to the super macro.

The term super macro isn't exactly new, but the fact that operators are talking about it now indicates just how much more they are looking to do with their existing radio access network (RAN) infrastructure before introducing new small cells or while planning a small cell deployment.

"Within the super macro concept, there's quite a lot operators can do to improve performance," says Heavy Reading senior analyst Gabriel Brown.

Along with adding sectors, using more spectrum bands, or employing carrier aggregation, Brown also includes in the super macro concept using 4x4 and 8x8 MIMO, active antenna systems, vertical sectorization, or beamforming.

The advantage of improving macro sites is that many of the basic elements that go into the total cost of ownership of a cell site are already in place, such as power, real estate rental, and backhaul, according to Brown.

I remember the folks from Ericsson mentioning about Super macros but I had not given any thoughts to it. Well, I went back to see what they have been talking about and found this:


Since it was not very clear, I found some additional information from an NGMN presentation as follows:




In order to reduce UEs’ frequently handing over between neighboring cells when moving at high speed which results in voice service or data download breakouts in the railway/subway/highway scenario, different RUs in different sites using C-RAN architecture can cooperate with each other and many macro chain cells can be combined to a super macro cell. In this burst communication scenario, network performance has higher priority than network capacity.

So my suspicion is that Super macros would be ideally using C-RAN where it would be possible to combine what could be many macros into a 'super macro'.

If I start thinking about it, there can be additional uses of the super-macro:

  1. Carrier aggregation - scenario 4 - see here. In Release-10 scenario 4 is not possible because of different timing advance requirements but this has been resolved in Rel-11. Super Macros can be useful in this scenario where small cells provide capacity, super macro provides coverage and reduces the need for constant handovers, etc.
  2. NCT - related to the above - see here - again, smaller cells (metrocells/microcells) using NCT to provide capacity, super macro for coverage
  3. Phantom Cell - see here - related to 1 and 2 above, super macro is the coverage, connectivity and mobility layer, small(er) cells are phantom cells that provide higher data rates. 

Anyway, a lot of information is pure speculation so feel free to add more info or correct my understanding.

3 comments:

  1. Note that the Phantom cell concept (data only bearer) was removed from 3GPP Rel-12 at last month's RAN Plenary because the gains were not clear enough. It may be back during Rel-13 but will have to prove itself

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  2. Manoj Das (via Het Net group on Linkedin)9 October 2013 at 07:27

    Thanks Zahid for posting. quoting the original statement here "According to Sutton, a super macro would typically have multiple radio access technologies (RAT), three-to-six base station sectors, and operate in multiple frequency bands using carrier aggregation techniques. It could be a standalone base station or a hub for subtended, smaller micro cells. He added that infrastructure sharing is vital to the strategy as well." IMHO here Carrier Aggregation is cited out of context. The EE executive wanted to convey they wanted to go for multi carrier and multiband deployment before moving to small cells. Here in the US, ATT deployed up to 6 carriers per sector in various bands. So the option is exhausted here. Sector splitting is relatively old concept belongs to 2009 era. And adding capacity to sector does not make much sense, since we can identify urban hotspots with Schema Overture kind of tools or proprietary OEM tools. We have to add capacity where its required, not the foot print of the entire sector. Again, in my humble opinion its not adding more value to the network and user experience with the approaches mentioned by the executive of EE. Kindly share your thoughts.Thanks Zahid for posting. quoting the original statement here "According to Sutton, a super macro would typically have multiple radio access technologies (RAT), three-to-six base station sectors, and operate in multiple frequency bands using carrier aggregation techniques. It could be a standalone base station or a hub for subtended, smaller micro cells. He added that infrastructure sharing is vital to the strategy as well." IMHO here Carrier Aggregation is cited out of context. The EE executive wanted to convey they wanted to go for multi carrier and multiband deployment before moving to small cells. Here in the US, ATT deployed up to 6 carriers per sector in various bands. So the option is exhausted here. Sector splitting is relatively old concept belongs to 2009 era. And adding capacity to sector does not make much sense, since we can identify urban hotspots with Schema Overture kind of tools or proprietary OEM tools. We have to add capacity where its required, not the foot print of the entire sector. Again, in my humble opinion its not adding more value to the network and user experience with the approaches mentioned by the executive of EE. Kindly share your thoughts.

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  3. An interesting point of view. This is inline with the Massive MIMO concept....building up a Massive antenna on actual base stations..and then adding small cell together.
    An explanation of that is here: Hosseini, K., J. Hoydis, S. ten Brink, and M. Debbah, "Making Smart Use of Excess Antennas: Massive MIMO, Small Cells, and TDD", Bell Labs Technical Journal, issue on Next-Generation Wireless Technologies, vol. 18, issue 2, 09/2013.
    http://www.flexible-radio.com/sites/default/files/publications/10/Making%20Smart%20Use%20of%20Excess%20Antennas21602_ftp.pdf

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