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Home Multi Antenna MIMO MIMO DL Frame LTE Uplink MIMO AAS Antenna Diversity LTE HARQ HARQ Type II ARQ vs. HARQ
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LTE Uplink MIMO and frame format.
In MU-MIMO, multiple user terminals can transmit simultaneously on the same resource block.  Only one transmit transmit antenna is required for mobile. This techniques is only possible with use of orthogonal SC-FDMA modulation on UL.
Uplink MIMO: MIMO schemes for LTE Uplink are different in comparison to Downlink. The Uplink (UL) is representative of a data link where Mobile is the transmitter and eNodeB is the receiver.  
Evolved Packet Core (EPC) system architecture for all IP.Mobility Management Entity (MME),
Serving System (S) Architecture (A) Evolution (E) Gateway or Serving Gateway SGW.
Packet Data Network (PDN) SAE Gateway
Enhanced Packet Data Gateway (ePDG)
Multiple antenna techniques - MIMO, Adaptive antenna systems - AAS and Antenna diversity - AD
4G LTE - Long Term Evolution topics from here

As we have already discussed, MIMO techniques are multi-antenna techniques to support higher data rates on radio links. These techniques are ok for Downlink(DL) where transmitter is eNodeB but in case of UL it gets complex for mobile entity.

 

So in order to reduce complexities in mobile UL path, a different antenna scheme is used. This scheme is called MU-MIMO, where MU stands for Multiple Users.

MIMO DL Frame.
AAS.

SC-FDMA is single carrier FDMA technique to provide multi user orthogonality and efficient frequency domain equalization.  This transmit technique is also know as DFT spread OFDM.  So the main difference in this technique is involvement of DFT processing.

 

Detailed processing of LTE uplink transmission is shown in block diagram below.

Data bits from software LTE  stack.

scrambler

FEC coding and Interleaving

Modulation symbol mapper

DFT

IFFT

Cyclix Prefix Adder

RF front-end :

DAC’s and filters

Sub-carrier mapper

RF link transmission