Forums

MIMO and AAS

Started by karthikbalaguru October 1, 2007
Hi,

What is the difference between  multiple input multiple output (MIMO)
system and
Adaptive antenna system (AAS) ?

I find the WiMAX uses MIMO and AAS . But, the definition appears to be
the same.

Both the systems are exploiting more than one antenna to improve the
coverage and the system capacity.

I wonder why different naming convention for the same system !! :(:(
Is there any significant features/differences in MIMO and AAS ?

Thx in advans,
Karthik Balaguru

On Oct 2, 2:03 am, karthikbalaguru <karthikbalagur...@gmail.com>
wrote:
> Hi, > > What is the difference between multiple input multiple output (MIMO) > system and > Adaptive antenna system (AAS) ? > > I find the WiMAX uses MIMO and AAS . But, the definition appears to be > the same. > > Both the systems are exploiting more than one antenna to improve the > coverage and the system capacity. > > I wonder why different naming convention for the same system !! :(:( > Is there any significant features/differences in MIMO and AAS ? > > Thx in advans, > Karthik Balaguru
Hi, I got some info from internet. There are differences between MIMO and AAS Antenna Technologies:):) It appears that cost-effectiveness comes in terms of the antenna and MIMO (Multiple Input, Multiple Output) and AAS (Adaptive Antenna System) are competitors. MIMO delivers the same coverage as AAS MIMO delivers higher capacity than AAS MIMO is lower in complexity and cost than AAS MIMO is more scalable than AAS. MIMO is more predictable in performance and can grow through additional sectors and/or additional antennas MIMO works well in all environments (rural, suburban, urban), switching modes to deliver users the best experience. MIMO outperforms AAS for mobile applications: MIMO maintains performance at speed and provides a predictable environment for easier and more reliable hand-offs. MIMO is the basis for all 4G plans- widespread investment in developing MIMO technologies will ensure advantages are maintained. So, it looks like in all aspects, MIMO is equal to or superior to AAS Refer - http://www.nortel.com/solutions/wimax/collateral/nn118160.pdf Thx, Karthik Balaguru
karthikbalaguru wrote:
> Hi, > > What is the difference between multiple input multiple output (MIMO) > system and > Adaptive antenna system (AAS) ? > > I find the WiMAX uses MIMO and AAS . But, the definition appears to be > the same.
No.. MIMO uses the fact that if you have multiple receivers and transmitters at each end of the link, the properties of the paths are uncorrelated to some degree, so you can spread your data across the multiple paths, reducing the bit rate on any one path. One use would be to use some sort of FEC coding, transmitting multiple bits for each data bit to achieve a lower overall bit error rate (after coding/decoding). AAS is more like adaptive beamforming In the limit, they are similar.
> > Both the systems are exploiting more than one antenna to improve the > coverage and the system capacity. > > I wonder why different naming convention for the same system !! :(:( > Is there any significant features/differences in MIMO and AAS ? > > Thx in advans, > Karthik Balaguru >
On Mon, 01 Oct 2007 15:04:16 -0700, karthikbalaguru
<karthikbalaguru79@gmail.com> wrote:

>MIMO delivers the same coverage as AAS
Hi Karthik, Only with the qualification that AAS may be steered to the same points of coverage of MIMO - and that is not always assured.
>MIMO delivers higher capacity than AAS
What is capacity? There are counter-arguments (depending on capacity's meaning, there are several) that would invert this claim.
>MIMO is lower in complexity and cost than AAS
An engineering system solution is not always about one component cost.
>MIMO is more scalable than AAS. MIMO is more predictable in >performance >and can grow through additional sectors and/or additional antennas
You should study the information and skip the claims you've heard.
>MIMO works well in all environments (rural, suburban, urban), >switching modes to deliver users the best experience.
This is not an antenna issue.
>MIMO outperforms AAS for mobile applications: MIMO maintains >performance at speed and provides a predictable environment for easier >and >more reliable hand-offs.
If AAS is boresight along a transportation corridor, this is no longer true.
>MIMO is the basis for all 4G plans- widespread investment in >developing >MIMO technologies will ensure advantages are maintained.
It's only advantage in this list you've constructed.
>So, it looks like in all aspects, MIMO is equal to or superior to AAS
Look again - your PRO MIMO statements are far too under qualified. 73's Richard Clark, KB7QHC