Cambium 650 Trunk Solution / CompTek Blog

The words "Cambium", "Motorola", "Orthogon" among radio operators are widely known and are associated mainly with positive feelings. In almost every city in the country, you can see characteristic elongated devices at offices, gas stations, and houses, sometimes in a flattened reflector - pmp100 subscriber devices, better known as Canopy, known for their stable operation even in difficult interference conditions. Less often you can see the manufacturer’s PTP series, since these productive solutions are usually found on the masts, and channels with a range of up to 100 kilometers are built on them.
The key advantage of the systems of these ranges is high performance, the ability to work with obstacles in the Fresnel zone, the reliability of the solution, and the disadvantage mentioned at the beginning is the high cost.
However, in the coming year, cambium overcomes the stereotype and offers a more affordable trunk solution - with all the positive qualities of the 600 series, more performance and less heat.
So today we’ll explore the Cambium 650 Series , which offers us 450 Mbps of bandwidth, latency of less than 2 ms and high range.

Further under the cut - a lot of graphs, tables and screenshots.

The 650 Series equipment is the continuation of the idea of ​​the 600 line - a high-performance line capable of working even if there are obstacles in the Fresnel zone. When developing the system, the objectives were to preserve the positive features of the solution, increase productivity and eliminate the following disadvantages:

• High cost;
• Large block;
• High power consumption.

Comparing solutions, we can say with confidence that the tasks are solved - the weight and energy consumed have decreased, productivity has increased:

	650 series	600 series
Productivity, Mb / s	450	300
Temperature conditions, range ° С	-40 ... + 60	-40 ... + 60
Power consumption, W	thirty	55
The mass of the active part, kg	4.1	4.3
Cable ports	Gigabit Ethernet, SFP, 802.3at Power Supply	Gigabit ethernet

Functionally, the device is an all-weather solution with a gigabit port and an SFP slot, thanks to which the system can be installed at a distance of more than 100 meters from the thermal container.
Power is provided by twisted pair; There are models with both a built-in antenna and a connector for connecting external antennas.
From a network point of view, the system functions as a bridge, with the ability to:

• Vlan filtering;
• Prioritize traffic
• Span overload alerts for routers.

Management is carried out through a graphical menu, but there is telnet, and support for control systems.
System performance is regulated by a license - thus, the initial costs of the system are reduced, and with increasing needs, it is enough to purchase a file to expand the performance to 125, 250 or 450 Mbps.
I would like to note the ability to temporarily activate a license of the maximum type, which allows you to evaluate whether your customers need such performance. The system works under a temporary license for up to 2 months, while the license can be suspended and renewed - this is very convenient for sets of test equipment.
Let's see what the new line can offer in comparison with the solutions of other manufacturers common in our market:

	Cambium 650	Infinet omx	Ubiquity rocket
Useful performance, Mb / s	450	210	200
Package performance, kilopack / s	900	200	20
Power and sensitivity for 200 Mbps, dBm	25; -69	23; -75	21; -75
Power and sensitivity at maximum performance, dBm	23; -62	23; -75	21; -75
Description	The development of the famous 600 series trunk	Well-known broadband access solutions in Russia. The range includes both the point-to-multipoint family and trunk solutions. Equipment advantages: high performance, various traffic processing settings, cold resistance.	A well-known low-cost solution, the advantage is high power at a low price.

According to the results of the analysis, a significant advantage of the Cambium solution in the main parameters can be noted:

• Performance;
• Processor power;
• Power output for complex modulations;
• Spectrum analyzer working without turning off the radio channel;
• The ability to receive and transmit at various frequencies;
• SynchroEthernet Support;
• The time division of the signal, the ratio of traffic (incoming to outgoing) in the proportions of 1: 1, 1: 2, 2: 1, adaptive.

Test results

We tested the 650 Series with the Optiview XG hardware generator and power meters.
Maximum performance in the main frequency bands was checked by an increasing flow of data (green fill - applied load, marks - achieved capacity). Traffic is transmitted through the channel, reflected and received by the transmitter. Thus, the results are considered as full-duplex, bidirectional data flow.







Please note: in this test we used large frames — while, according to statistics from most of our customers, the frame size of modern networks is now around 300 bytes.
We will conduct a performance test again using frames of the following sizes: for Cambium, Infinet we use 64 bytes, for Rocket - 128 bytes.





Thus, in terms of performance, Cambium wins a clear victory.

Performance test results for intermediate frame sizes, tabulated:

Performance in various frequency bands

Clear and beautiful graphs of the bandwidth in the frequency bands common to all decisions (abscissa axis - frame size in bytes, ordinate axis - bandwidth in Mbps):

20 MHz:


40 MHz:


For those who want to repeat the test, I draw attention to the fact that Infinet includes traffic compression - therefore, a random packet filling generator is required. When measured with uniformly filled frames, on packets of a certain size, the performance exceeds 170 Mbit / s.

Receiver sensitivity check

Probably, many noticed that the sensitivity of the line under consideration at maximum performance is lower than the compared models. On the one hand, this is logical: the useful performance of 10 Mbit / s per MHz forces the use of modulation with 256 positions, and competitors use 64 position modulation, but there is a difference in measurement methods.
We check with the help of attenuators at what level of reception the system supports performance modulations, while loading the channel with traffic. Cambium

test bench
layout, 40 MHz spectrum width

	Declared sensitivity, dBm	The measured sensitivity, dBm
256QAM	-62	-56
64QAM	-64	-63
16QAM	-69	-67

Ubiquiti 40 MHz Spectrum

	Declared sensitivity, dBm	The measured sensitivity, dBm
64QAM	-75	-61
16QAM	-84	-75

We see that the Ubiquiti system does not set the maximum speed at the specified signal level, unlike Cambium - the use of chipsets for mobile wimax made it possible to work effectively with a significantly lower fade margin, use modulation with 256 positions and significantly improved the ability to combine networks thanks to a more stringent spectrum mask.
We see that on modulations up to 64QAM inclusive, the system showed a sensitivity corresponding to the declared one; on maximum modulation, the sensitivity is slightly less.
Ubiquiti equipment showed a significant difference in declared and tested sensitivity.

The plots of the real and declared sensitivity, having adopted the attenuation of 1.5 dB in the cable (along the ordinate axis - dBm):


Thus, we did not see any advantages for solutions on the Wi-fi platform, except for price. If we add that Cambium has full-fledged MIBs, soon the line support will be added to the CNS control system, and the proprietary radio planning product calculates obstacle channels for free, then the winner of the comparison becomes obvious. Well, we are waiting for practical confirmation outside the walls of the laboratory - in the spring we are going to compare products on real radio channels.

We also plan to write an article about the new 650S solution. This is a modification of the 650 series, specially designed for highways between cellular stations 3 and 4 generations.

As a bonus to detailed testing of the technical side of the device, without claiming to be an authorized course, we offer to take a brief look at the main menu of the device.