In reply to a post by yarwell:

In reply to a post by pcoventry76:

Most of the current EE cells are linked to 1gbps VM lines. Some even have 10gbps when needed.

what's an EE cell ? no way a mobile base station needs anywhere near that.

Virgin Media are providing a 1 Gbps synchronous Ethernet mobile backhaul service for EE and 3 although probably not from each base station but the local/regional aggregation nodes.
2011 press release

In reply to a post by yarwell:

what's an EE cell ? no way a mobile base station needs anywhere near that.

You sure? I'd have said 1gbps is required, and 10gbps would be in the planning for future stages.

Assume a single cell site; DC-HSPA around 20mbps per user; or LTE at 30mbps per user, and 250 concurrent users = 250 x 30 = 7500 mbps backhaul. (and I gather 250 users on a mast is quite low).

Its people like O2 and Vodafone who are still using 100meg to the mast, which is why its unusual to see over 1.5mbps on a Vodafone 3G / HSPA connection.

In reply to a post by jchamier:

You sure? I'd have said 1gbps is required, and 10gbps would be in the planning for future stages.

Assume a single cell site; DC-HSPA around 20mbps per user; or LTE at 30mbps per user, and 250 concurrent users = 250 x 30 = 7500 mbps backhaul. (and I gather 250 users on a mast is quite low).

HSPA and LTE aren't dedicated bandwidth. They're a group of channels split between everyone on the cell site and contended. There's nowhere on DC-HSPA in the UK that will deliver 100Mbps on a single cell, let alone 20Mb to 250 users on a cell. 3 I believe max out at 42Mbps per cell.

Even the LTE networks don't have enough capacity to allow a single user to hit 100Mb even if they're the only person on the cell. A single STM-1, 155Mb, is ample for a mobile cell. The bottleneck is going to be on the RF between phones and cell, not the backhaul.

If a single cell site could deliver 30Mb to 250 users simultaneously there would be no need for fixed line broadband.

Edited by deleted (Mon 27-May-13 11:53:17)

Openreach are busy providing 1Gbit ethernet circuits for VF and O2. 1Gbit links have been pretty standard for MBNL for some time.

In reply to a post by Ignitionnet:

If a single cell site could deliver 30Mb to 250 users simultaneously there would be no need for fixed line broadband.

So why are the mobile telco's busy signing up backhaul companies to install 1gig+ links?

20 Mhz frequency allocation * 4 bits/Hz = 80 Mbits/s total available bandwidth. LTE data.

If 1 Gig circuits cost about the same to provide as 100M then their would be no point in picking the small one, but your estimates are way OTT even for LTE.

Plenty of mobile base stations have modest microwave backhaul out of town.

So why are the mobile telco's busy signing up backhaul companies to install 1gig+ links?

I guess "are they" is the first question.

The referenced EE / VM thing talks of a gigabit sync-E network (backbone ?) but says nothing of base station capacity.

As the man said, the MHz available to each operator is small and the multiplier to turn that into bandwidth depends on the technology but isn't a large number. "Realistic sector throughput" is the statistic of interest.

BT's mobile backhaul has some standards / interfacing issues that sync-E should sidestep "the service bandwidths which BT Wholesale delivers with MEAS currently are
65Mbit/s to sites connected with 100Mbit/s Openreach Ethernet access circuits, and
300Mbit/s to sites connected with 1Gbit/s Openreach Ethernet access circuits." - OFCOM.

In reply to a post by yarwell:

20 Mhz frequency allocation * 4 bits/Hz = 80 Mbits/s total available bandwidth. LTE data.

If 1 Gig circuits cost about the same to provide as 100M then their would be no point in picking the small one, but your estimates are way OTT even for LTE.

Okay, I was going by expectation rather than actual knowledge. The people I know in the US on their LTE systems can have 5 or 6 people in a meeting room all using LTE dongles in laptops and getting 40megabit+ each - so they must have quite a different amount of MHz. :-/

Plenty of mobile base stations have modest microwave backhaul out of town.

That might explain why in north east hants, the Vodafone and O2 networks generally manage about 1.0 megabit and often less, and the two EE brands and Three can manage 8megabit in the same locations. Perhaps microwave capacity isn't enough for this decade?

There are some interesting calculations on this page on LTE capacity.

For 20MHz of spectrum, it estimates 298 Mbps in 4x4 MIMO. It also includes graphs constructed from tables in the 3GPP specs: 75Mbps in SISO, 149Mbps in 2x2 MIMO.

But those are peaks. The average for the cell, when it includes trickier users out near the borders of the cell, is going to be a lot lower. I think the going expectation (for 2x2 MIMO) is 1.8bits/Hz, making downstream about 36Mbps per 20MHz cell (with 18Mbps on the upstream 20MHz).

Microwave can happily do 1Gb and upwards however if an operator is paying for an E3 that's what they'll get.