Sinteticamente:
Precision Timing
Rugged, hi-power, linear 2x2 MIMO radios specifically designed
for outdoor PtP bridging and PTMP AirMax basestation applications.
Seamless AirMax Integration
Just like the original Rocket M Series, Rocket M GPS units seamlessly integrate with AirMax BaseStation and Rocket Antennas.
GPS Signal Reporting
AirOS was upgraded to take full ad- vantage of the new GPS hardware in Rocket M GPS units; easily manage/ monitor GPS satellite signals.
No Co-location Interference
Synchronized transmission among Rocket M GPS powered BaseStations effectively eliminates co-location interference.
http://www.ubnt.com/rocketmgps
Un altro passo verso IL TDMA completo... vedremo i reali benefici e le mosse dei diretti concorrenti...
UPDATE: Come funziona AirSync
Rocket GPS and Airsync FAQ
1) How does Airsync protocol work?
The airsync protocol requires Layer-2 connectivity between the participating APs.
In each sync-cluster: one of the APs is designated as the Master and the others as the slave.
A L2 bridged network can have as many sync-clusters as desired.
The Master and the slaves exchange synchronization information over Layer-2.
Once synchronized the airmax TDMA transmit and receive slots of all APs are lined up. Hence all APs shall transmit at the same time and receive at the same time.
2) Can remote towers be synchronized?
Yes as long as the latency of communication between the towers is less than 30 ms.
One needs to avoid situations where the stations connected to the towers can *hear* more than one tower or where the towers can *hear* each other's stations.
When using different frequencies, the frequency rejection on the radio will help shave off 10-40 dB depending upon the MHz difference, relaxing the requirement.
e.g. If one STA hears its own AP at -60 dBm and hears the other synchronized APs at -80 dBm, it would only have a 20 dB Signal to Interference Ratio. Higher rates (MCS6/14, MCS 7/15) will not be possible in this case.
If the APs were 20 MHz apart, the adjacent channel rejection factor of 10 dB can be added giving a 30 dB Signal to Interference Ratio. This would make MCS6/7 or 14/15 possible on the link.
Increasing the separation in MHz will improve the ratio.
So it will all depend on the Signal to Interference Ratios.
3) Can I deploy just one Rocket GPS, and have my other Rockets synchronize with it?
No, each airsync participant needs its own GPS input. The reason here is that a Layer-2 connection does not provide predictable latency for communicating timing information (at the resolution that we need).
4) Can I re-use the same frequency for all APs?
Yes the same frequency can be re-used as long as the situation described in (2) is avoided. Realistically this would only work for back-to-back deployments.
5) Do the APs share the medium capacity once synchronized?
No, as long as the situation described in (2) is avoided, each airsync participant gets the *full medium capacity* and is not affected by traffic patterns of its peers.
The exact throughput in Mbps achieved by each airsync participant will depend on individual link quality.
Hence adding more APs shall increase network capacity.
6) I would like to synchronize APs on a tower, but do not want to bridge them. Can this work?
Yes. One can configure the airsync protocol to use a specified VLAN. Hence only the specified VLAN needs to be bridged.
7) Can I configure the Down/Up timing ratio?
Yes. The timing ratio can be configured at the 'Master' and shall be used by all the slaves.
8) If I need to use different frequencies to mitigate the problem described in (2) above, why do I need GPS sync?
As discussed in (2), increasing the frequency separation, increases the SIR.
e.g. at 60 MHz separation the rejection is about 50 dB. Since the APs are co-located the would hear each other at 27-50=-23 dBm.
If the signal strength to one of the clients was -60 dBm, the SIR in this case is -37 dB (negative). This would prevent the AP from decoding even a MCS0 signal (as it needs a SIR of about +6 dB) from the station if any one of the other APs transmit.
Hence the need for synchronization.
9) Do I need GPS on CPEs?
No, Airsync is AP side functionality. To synchronize an AirMax network, only a hardware upgrade on the AP side is required (RocketMGPS). No station side hardware upgrade is needed.
