Quote Originally Posted by rimoucha View Post
Hello,

We use normal compression by default.The antenna type is Huawei ATD4516R8.
You see, this is the trick. If you split up a single 20MHz cell to two 20MHZ soft split cells, with normal compression you can still fit a 10gig CPRI.

In our case, we already have 2x20MHz on the same sector, which fills the complete 10gig CPRI with normal compression. And if I would split this, I will end up with four 20MHz cells on the same sector. And intra freq soft split does not support enhanced compression. Even if it would, I will end up with about 9.8gig required CPRI bandwidth, and due to the CPRI overhead, a 10gig CPRI link is not able to fit that. The point is: I will need to add the second pair of fiber to the RRUs, otherwise I run out of CPRI bandwidth.

If you think about it, its completely logical: after you split a 65° cell, you will end up with two 30° cells, both with their own individual radio resources, that is where the gain is coming from. How could it be possible to do this without extra CPRI and other cell level resources? The answer is: you can't. Huawei is not completely honest about soft splitting and they use a vague language even in their feature description to conceal the fact that it is not completely true that you don't need to do anything, just add licenses:

What is true about soft splitting, is you don't need to add/change: antenna, and RRU. However, if you maxed out your BBU boards already, you will need to add BBU resources, and if you maxed out your CPRI already (with normal compression), you have to add that as well. Plus all the cell number based licenses has to follow as well (at least that part is clear in the feature description).