Hi all,
Need clarification on this.
As I know Spacial Diversity (SD) is required for over water solution.
May I know if we can (not using SD) with over water solution.
If so, what is the recommended distance to not use SD.
When using SD is PTP670 is the only model for unlicensed to use this kind of solutions?
I can’t speak to LP’s SD options, but as to radios that can handle reflections/multipath/link fade (common issues with shooting over water), I think the ePMP 4000 series is probably the best Cambium has to offer. These radios employ OFDMA and based on our testing handle challenging path conditions better then any other Cambium radio we’ve used.
Can share your longest distance over water link using ePMP 4000 series? and the result u get.
We have no e4k shots over water… but we have tested it in multiple nNLOS situations against PMP450 900MHz, high power PMP450 3GHz, Baicells and cnRanger LTE 2.5GHz, etc. and e4k 5GHz has bested them all in terms of link stability and overall throughput.
m3lody,
Multi-stream OFDM, with 90 degrees difference in polarity, and other features such as beamforming, radically change the need for SD. SD is required when a system uses very high data frame rates - in high frame rates, there is no time for multipath to resolve itself, so errors caused by reflections compound, lower the MCS because of error rate, and eventually the link fails. The 670 is a unique product in that it has a robust over the air protocol. We have customers using single 670’s on paths up to 6 miles (10km) from mainland to islands.
I also know that another manufactuer who’s product has robust NLOS performance has links 22km long over water - SD is not possible with their product.
SD is required for PTP820/850 systems over water because the frame rates are high, the system uses single stream, there is no beamforming, or any other multipath mitigation algorithm. The system is designed for flat out capacity, so SD is required to sort out the most significant probable reflections.
I’m sure someone in our world has run ePMP 4500 over water successfullly. I know that I have done a number of Link Planner projects for over-water systems, and performance was good in the simulation. The key to great performance is to use the smallest channel possible to get the capacity you need.