Einstein Field issues Handled correctly?

[philso]

The radios use a spread spectrum technique for transmitting the data at the most fundamental level. Various techniques are used to enhance the data throughput from what is achieved in the 802.11a,b,g to get the 802.11n data rates.

One of the benefits of using spread-spectrum techniques is the very high noise immunity giving a highly reliable connection. More reliable than narrow band transmission techniques. Instead of transmitting a signal over a narrow bandwidth, the information is spread over a very wide bandwidth, at a relatively low amplitude. The receiver de-spreads the received signal, restoring the original narrow bandwidth and high amplitude. Narrow-band interference sources (radar, noisy electrical equipment) would be squashed in amplitude and spread over a wide bandwidth by the de-spreading process in the receiver and the majority of the noise energy can be filtered out very simply. That is one of the reasons why this technique was used by military radios for many years before the ISM band was made available for civilian use.

Due to how the spread-spectrum transmission technique works, it is difficult to believe that only one or two channels can be corrupted for a whole match by a narrow bandwith, short duration transmission like the weather radars or wideband weather phenomena such as lightning. They ought to affect all channels in a similar way, simultaneously or not at all. The only way I can think of to adversely affect a single channel would be to jam it using a spread-spectrum transmitter set to the appropriate channel. Either FIRST missed some signal source when setting up the fields or someone was intentionally jamming. If find the latter hard to believe.

The radios are a consumer grade item but their design would have been tested very thoroughly by the manufacturer and their other customers. I would imagine that the teams experiencing trouble would have been able to check for connection before each match or they would have raised a concern and not allowed the match to start.

This leads me to ask if the FMS software that manages the robots through the 802.11n link may have some bugs in it. I am sure that the developers of this software would have tested it to the best of their abilities. However, there can be issues and conditions that only show up with certain combinations of hardware and other software. The FMS software would have far fewer users and instances of use, overall, than even low-volume commercial software so obscure bugs can be very difficult to trouble shoot and would probably require tools not available to the FTA at a competition. Perhaps the developers should visit one of the upcoming off-season events and bring all their tools and toys. That is what our engineers at work do when a customer experiences unusual behaviour that the Field Service people cannot fix.

At Alamo, one of the robots in the alliance opposing ours was immobile for the whole match leading to the match being replayed. If my memory serves me correctly, it was announced that 148 had become indicated as a no-show so their channel was shut down, rendering them immobile for the duration of the match. I have no way of knowing if our (148's) experience is at all related to what was seen at the CMP but the symptoms look similar. By the way, one of the other teams did all the scoring and handily beat our alliance single-handed