How does MIMO work in 802.11g standard?

[PaulHolland]

MIMO and WiFi

Hi All,

Does anyone have information on how MIMO works in the new 802.11g standard ??

I know it works with two antenna's but is it transmitting at the same freq. and at the same time ???... Does anyone have a block diagram or something like this for WiFi hardware ??..

regards,

Paul.

 

[cyberdome]

Re: MIMO and WiFi

Hi Paul and others,

Here is a link to a quite good tutorial paper regarding MIMO:
**broken link removed**

As you said, MIMO uses multiple transmit and multiple receive antennas.
The maximum achievable link capacity is proportional to min(NrxAnt,NtxAnt).

Using a space-time coder the transmitted data is split into several data streams.
Some space-time coders uses spatial multiplexing to increase the bit rate. Others
are using a technique called STTD to increase the link budget (i.e get higher SNR at the receiver). There can also be combinations of these techniques.

Some companies have their own enhancments of 802.11g to demonstrate the capabilities of MIMO. In IEEE there is a workgroup called 802.11n currently focusing on increased throughput for wireless LANs.

Regards,
cyberdome

 

[omara007]

Re: MIMO and WiFi

where can I find the draft of the IEEE 802.11a standard ?

 

[omara007]

Re: MIMO and WiFi

sorry I mean IEEE 802.11n standard ( not the famouse IEEE 802.11a one )

 

[flatulent]

Re: MIMO and WiFi

In general this relies on severe multipath arriving from widely spaced angles. The antenna algorithm finds two angles that contain rays that are independent. Then the two stations communicate different information on each path by virtue of the phased array antenna and the linearity of the RF hardware path associated with each antenna.

This multipath only exists in urban areas or remote areas with many hills and mountains. It will not work in situations such as two airplanes far apart over the ocean.

This method will be less useful in future when there are more stations. This is because the two angles have to not have another station's direct signal or multipath signal in the same direction on the same frequency.

 

[III]

Re: MIMO and WiFi

Hi All,

Does anyone have information on how MIMO works in the new 802.11g standard ??

I know it works with two antenna's but is it transmitting at the same freq. and at the same time ???... Does anyone have a block diagram or something like this for WiFi hardware ??..

regards,

Paul.

MIMO is used in the 802.11n standard now apple is integrating it in it's pirated iphone,does enyone know where can the draft standard be found?