@ vinay kumar thank you for you answer but If they communicate , what is penalty of mimo levels difference should the system pay?
Yes, if looked from the AP perspective (downlink), it should be called MISO. The RS and AP can be configured to work properly to enable the spatial diversity to maximize the sum rate for either downlink or uplink.
Alaa.
As the colleagues hinted, the remote station works with the AP as SIMO in the up link and MISO in the down link. In case of uplink the system will work giving a diversity reception gain. In the down link it can be operated as transmitter diversity system giving transmitter diversity gain. For single user NtXNr transmit and receive antenna one can only realize the smallest one as independent paths for spatial multiplexing. Thus for 3x1 system, one has only one independent path.
This means that this system will be diversity system.
Best wishes
Thank you Dr . Zeky , kindly , in 802.11 ax standard , there is important point im trying to understand it carefully which is related to the input signal ( message) to MIMO system of 802.11ax.
do the output signals from set of antennas in transmitter are copied of one signal (spatial diversity) or the transmitter will multiplex that signal among all available channels in MIMO system ?
thank you
Dear Alaa,
I do not followed the ieee standards of WiFi but following the 3x1 system previously discussed as said before it can only diversity transmitting system with three antennas. The simplest form of the transmit diversity is to transmit the same data by every antenna. But to increase the system gain one normally makes normally coding called space time coding STC, as Alamoti STC. So, the data to be sent is entered to STC block outputting number of equal rate streams whose number is equal to the number of transmit antennas.
Best wishes
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