gps sync

I plan on instaling a 4 ap cluster of epmps  with 2 ptp connections  on a single tower the 2 ptp connections will go north and south and have an additional ap at either end to service the north and south area customers that cant see the tower currently so 6 aps in total. 

My questions is how would i need to GPS sync these access points? I have a CMM 1 timing gear currently. Could this is used or is there another cheaper solution? Im thinking the internal GPS sync the epmp1000  have? I want to use as few channels as possible and avoid as much interferrence as possible. Should the ptp gear be the gps sync model or is the force ptp gear without sync sufficient? the 2 ptp shots will be about 4km in distance from the tower.  currently the customers that are extemely far from the tower need massive towers at their homes to get a signal. id prefer making the ptp solution with an ap at the end better for them as they wont need towers anymore. 

Is what im thinking possible?

I believe you should be able to use the internal GPS sync (using the included external GPS antenna) of the ePMP 1000. If the 2 remote APs are able to hear the cluster of 4 APs, then they should all be synced using the internal GPS. If you have another channel available for the PTP links, then you can use unsynchronised links; but if you want the whole network on a single channel I think a synchronised PTP link would be the best choice to avoid self-interference. 

Thank you for the response, 

Im still learning about this equipment as much as i can. Lots of new concepts for me.

We currently use pmp100 and have a cluster of 6 using 3 channels. kind of eats up the spectrum. youre saying its possible to use a single channel 360 degrees and have customer connect in all directions? That would make my life much easier lol. i only have 170 customers so it shouldnt affect 4 aps much once the upgrade is done right?

@geraldthunder wrote:

youre saying its possible to use a single channel 360 degrees and have customer connect in all directions?

No, in most circumstances, you cannot have more then 2 sectors at a site sharing the same channel. Cambium supports  back to back frequency reuse with antennas that are ideally 180deg from each other, in addition the antennas need very high front to back (F/B) ratios. To give you an example, a site with a 360deg, 6 sector array (6x60deg antennas), you could use back to back frequency reuse on (3) pairs of radios, which would reduce the amount of spectrum needed at the site in half, e.g. sync w/3x20MHz channels vs non-sync w/6x20MHz channels.

Please take a look at this forum post for additional detail on how GPS sync and back to back frequency reuse works.