I'm trying to get a handle on the specifics of RRU-BBU connections. Ultimately I care about the number of SFP/SFP+ transceivers an RRU is equipped with.
I know the RRU-BBU can be connected via either two-fiber with TX and Rx on different fibers, or single-fiber if bi-directional, so let's use the term 'links' instead of 'number of fibers' to keep things simple.
1. How many 'links' does an RRU need back to the BBU? What determines how many are required?
2. How many transceivers can an RRU handle? I know they aren't all identical, so what is typical, what is the max, etc.?
I think based on my research that the answer is very nearly always '1 link per RRH to the BBU'. (One exception I know of is the NSN FlexiRadio RRU which has three optical ports.) A colleague believes the answer is '1 per attached RF transceiver', which means multiple fiber links from one RRU. Who's right?
Another question - in a Ground Mount Option build, with the RRU located at the bottom of the tower, is the connection up to the panel copper or fiber? I read here that 'existing cables can be reused' which seems to imply copper in at least some instances.
Thanks.