Need Suggestions

[dcallejas]

Hello,

I just got a new Apartment Complex of 800 units. I have been using the NS2 for APs and the loco5 for backhaul. I give internet service to all tenants that live there. I use the nanos as AP that clients connect to.

Now you guys have this new nanoM and locoM, has anyone been using this units? Do you get the bandwidth its advertized? Need to setup this new complex and I would like to know what you guys suggest, use the regular nanostations and locosations or go with the NEW nanostationM and LocoStationM? What would be thr pros and cons?

Thanks

Daniel

[george]

Depends on your timing. Right now the M versions are a little hard to find, and the firmware is still getting the finishing touches.

If you can wait a month or so, you should seriously consider the M product line as you will get a lot better performance, and probably a longer product life than the existing ABG products.

My two cents...

[gmidia]

The M just means more bandwidth on the units. And that is where technology is moving to. So it is better to have an upgraded system as units are now being produced that are compartible with The M Products eg the new MacBooks support N on top of the a/b/g

[george]

M is NOT only about more bandwidth on the units. It means substantially better NLOS performance in an urban environment because of the dual antenna diversity. It also means AirMax which will give much better performance in a congested environment, and allow decent VoIP and video transmission.

However, if you are using AirMax, you will not be compatible with standard N protocols...

[WHT]

It means substantially better NLOS performance in an urban environment because of the dual antenna diversity.I'm curious how you came about that conclusion. What processes did you base that on?

[WHT]

Hint...You're not allowed to use the Ikegami Walfisch model to explain your conclusion.

[george]

How MIMO works

Qualcomm, a wireless chipset developer that acquired Airgo, the company founded by Dr. Raleigh, has the best definition of how MIMO works:
MIMO systems divide a data stream into multiple unique streams, each of which is modulated and transmitted through a different radio-antenna chain at the same time in the same frequency channel. A revolutionary technique that reverses 100 years of thinking about how radio signals are transmitted, MIMO leverages environmental structures and takes advantage of multipath signal reflections to actually improve radio transmission performance.
Through the use of multipath, each MIMO receive antenna-radio chain is a linear combination of the multiple transmitted data streams. The data streams are separated at the receiver using MIMO algorithms that rely on estimates of all channels between each transmitter and each receiver. Each multipath route can then be treated as a separate channel creating multiple “virtual wires” over which to transmit signals. MIMO employs multiple, spatially separated antennas to take advantage of these “virtual wires” and transfer more data. In addition to multiplying throughput, range is increased because of an antenna diversity advantage, since each receive antenna has a measurement of each transmitted data stream. With MIMO, the maximum data rate per channel grows linearly with the number of different data streams that are transmitted in the same channel.
That describes in a nutshell the basic tenants behind MIMO antenna systems.

RF Non-Line of Sight NLoS): This is a condition where the RF signal encounters significant physical interference along the link path and only altered RF signals reach the receiving antenna. These altered RF signals have the tendency to interfere with each other, often destructively which results in multipath fading, the bane of conventional radios using SISO technology.
Wireless pioneers like Dr. Raleigh decided to take advantage of the specific multipath phenomena in which received signals from one transmitting antenna will have different phase, timing, or signal strength characteristics from received signals transmitted by a different antenna. This line of thinking brought about one of those all too seldom “Ah ha!” moments. Using multiple transmit/receive antenna pairings to overcome multipath fading also compliments the concept of higher data rates being derived from having multiple RF streams.
The last piece of the puzzle and where MIMO technology finally came together was the advent of new and, in my opinion, amazing receiver technology. By using advanced digital signal processing hardware and very sophisticated algorithms that deal with space-time coding (http://en.wikipedia.org/wiki/Space-time_code), it becomes possible to decipher the multipath differentiated RF signals even though they are all on the same frequency.

http://blogs.techrepublic.com.com/wireless/?p=156

There are literally hundreds of articles and papers describing the function and advantages of MIMO in 11N.

On top of the theory, we've used Orthogon radios for years and have seen first hand the benefits in MIMO systems. Spatial diversity or polarity diversity, or both work wonders in an urban environment.

Our experience is that the benefit of polarity diversity MIMO is most pronounced in a 'hard surface' multipath environment, failing that a large spatial separation works well on long outdoor links. The Orthogon link calculator allows you to set various antenna spatial separations and see the results in link availabilty...

Note that the OP's 800 unit apartment complex is about as close to the ideal situation for N MIMO as you are likely to ever find!

George

[george]

Hint...You're not allowed to use the Ikegami Walfisch model to explain your conclusion.
I looked that up just for the hell of it.

I think you're overthinking the issue.

As a technician/technologist rather than a scientist (my parents were married and I work for a living) I'm comfortable that it has been clearly demonstrated in the field, time and again, that MIMO has huge benefits in a hard surfaced urban environment such as the OP described.

Additonally, 6 gig long-line operators have known for 50 years plus that really large spatially diverse antenna arrays are the way to go to combat fading due to ducting, inversions and other thermal artifacts that effect really long links.

You only have to hang out in our area around dawn in the Spring and spend some time listening to the diversity switches clicking to know that spatial diversity is a winner.

Orthogon radios do all that automatically of course, plus picking the best channel on their own, and I receive the email describing the channel change and get to review the logs at my leisure.

Suits me...

George

[dcallejas]

So in conclusion the new ubnt mimos are the way to go!!! Now I hope they dont take a year to come out!!! I have a couple of months to begin setup of this new complex.

Now another question, If I put a New M series AP on an existing network using the regular nanos as cpe, will they communicate with the M series? Want to start inplementing the new M series in my small wisp in nicaragua, but I dont want to have to change al ns2 at one time...

[WHT]

There are literally hundreds of articles and papers describing the function and advantages of MIMO in 11N.I'll stick with the real world results of actual field testing that gives a a 10 dB advantage under marginal LOS conditions for a net advantage equal a better LOS condition.