Lower you go in where you do the split in the NR stack, higher are the transport requirements in terms of bandwidth and latency, but higher is also the gains related to inter-site coordination, like CoMP.
On 3GPP R15 only Option 2 is standardized, the lower splits are open for vendor implementation. Not sure on which the “open” initiatives are working on, maybe someone else can comment.
The “tradicional vendors” are all present here, Huawei, Nokia, Ericsson, ZTE, Samsung, but the new guys from the virtualized/open solutions are starting to present its teeth to bite some slices of the market share, like Altiostar-Techmahindra, Parallelwireless, etc…
What I understood in some of the posts , lower the transport bandwidth will be higher.
Can you point me a URL where I can understand the Transport impact for each layer.
I believe the MIMO/Coding schemes/Bandwidth of the carrier also plays major role in Transport need.
I am still struggling to find one good source to read these relationship.