Cambium Networks – Outdoor PTP & PMP

I had heard a few years ago about Cambium Networks being born out of a split of the company from Motorola 3 years ago. Before this time I worked on an outdoor deployment with the Motorola Canopy division in the 3.6GHz range that utilized the technology shown to Wireless Field Day 8. It was interesting to me to hear more about how it exactly works, especially as I had gained a lot more knowledge of the fundamentals of the Wi-Fi PHY in studying for the CWAP exam. Below are some of my thoughts.

First of all, the market that Cambium targets is primarily outdoor connectivity and they have three solutions they specialize in; Access, where end user connectivity is required in difficult to reach areas for a wired internet provider, such as rural housing, Backhaul, where edge to edge high performance is a must and Transport, where a layer 2 bridge is required to support any type of higher layer traffic. They can use both licensed and unlicensed bands to provide for those solutions. There are many use cases for wireless here and Cambium is very focused on competing in this area strongly with other players.

Technically, the most interesting part of their solutions is the use of GPS sync in the radios to govern when a packet is sent. Although their solution is very similar to the 802.11 PHY, essentially what they have done is removed all contention based access control as the GPS sync feature governs when APs can send and receive data. This allows for a more efficient MAC, but at the cost of potentially interfering with existing users of a band who use contention based access. In addition to this, Cambium products use TPC to control power levels to reduce secondary interference effects from the signal being too strong and hitting other parts of the antenna array. The system as a whole is very deterministic. Some of their AP models are shown below;

The ePMP 1000 AP
5GHz Force 180

It was great to hear from Cambium at Wireless Field Day 8 and I hope they will decide to rejoin us in the future. I must admit to being a bit concerned that their deterministic tech would cause issues for Wi-Fi, however as they are primarily an outdoor company this should mitigate that to an extent.

Notes:
* Talking about outdoor broadband product line
* Connectivity in Access, Backhaul and Transport networks
* Access is end user connectivity in difficult to reach areas where wired connections won’t work.
* Backhaul is edge to edge where high performance is a must.
* Transport is a layer 2 bridge to support any type of higher layer traffic.
* Can use both licensed and unlicensed bands
* Expanding to products inside the house to integrate connectivity
* Provide Carrier services as alternative to DSL, etc.
* Connectivity for video surveillance devices
* Infrastructure backup connectivity for redundant connectivity for networks.
* Extension of broadband access where it is needed.
* ePMP is SOC chip based and PMP is FPGA proprietary chip
* EPMP;
** GPS sync radio and unseen radios, for lower cost modules.
** Higher gain antennas for longer distance connections 25dBM
** Uses different subscriber modules to reach remote structures.
** Service providers usually spread the cost over about 8-9 months
* EPMP Tech differentiation;
** #1 performance degradation is self-interference.
** Is caused by base stations being out of sync before they send the transmission
** EPMP chips do not use contention based scheduling
** GPS sync is the methodology used to make sure that the base stations send signals at the right times.
** Also uses TPC to make sure that the signal from subscribers drop their power to match
** System is deterministic and although similar to the 802.11 MAC is not the same.
** GPS sync allows for frequency reuse
** Unsynchronized solutions can suffer from the hidden node problem
** Synchronization eliminates primary interference.
** Secondary self interference can also happen with certain antennas, needs TPC to control this.
** High front amplification and high back attenuation is require to avoid this.
** Scalability with competitive scheduling can be difficult to achieve due to time constraints.
** Instead of individual propagation delay, the turnaround time for packets is calculated to make the sending more efficient
** Has an Air Fairness scheduler and Interference optimized rate adaptive algorithms
* CnMaestro Demo
** Provides simplified network management from the cloud
** Instant discovery of APs to connect to cloud using https
** Built as multi-tenancy, hosted on Amazon
** Supports copilot, ePMP currently and soon PMP450 and PTP650
** OnBoarding of devices, configuration and monitoring handled via cloud
** Integrates Google Maps for placement of where devices are located

Leave a Response