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LTE supports data rates upto 100 Mbps for downloads and 50 Mbps for uploads. The the high throughput needs to be transmitted over the air without causing packet corruption or packet loss. This is also used in WiMax antenna as an option
LTE MIMO - Multiple Input Multiple Output Multi-antenna scheme - 2x2 MIMO
Mathematical equations of MIMO
In order to drive the mathematical equations of MIMO lets first discuss the theoretical setup of a 2X2 MIMO.
In order to drive the mathematical equations of MIMO lets first discuss the theoretical setup of a 2X2 MIMO.
LTE MIMO.
Downlink MIMO
LTE downlink by default requires MIMO 2x2 antenna configuration (In WiMax its optional). By MIMO 2x2 we mean 2 transmit antennas at the base station and 2 receive antennas at the mobile. Antenna configurations with MIMO 4x4 are also discussed in the standard.
Uplink MIMO
MIMO schemes for LTE Uplink are different in comparison to Downlink. Uplink (UL) is a data link in which Mobile is transmitter and eNodeB is receiver. 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.
Downlink MIMO
LTE downlink by default requires MIMO 2x2 antenna configuration (In WiMax its optional). By MIMO 2x2 we mean 2 transmit antennas at the base station and 2 receive antennas at the mobile. Antenna configurations with MIMO 4x4 are also discussed in the standard.
Uplink MIMO
MIMO schemes for LTE Uplink are different in comparison to Downlink. Uplink (UL) is a data link in which Mobile is transmitter and eNodeB is receiver. In order to reduce complexities in mobile UL path, a different antenna scheme is used. This scheme is called MU-
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.
h11
h12
h21
h22
Matrix channel and parameters
h11, h12, h21 and h22
h11, h12, h21 and h22
Transmitter
Receiver
From the setup of 4G LTE 2x2 MIMO, we can observe that each receiver is getting two streams of data one from Transmitter 1 and other from transmitter 2. The straight line is a direct path whereas angle path is an indirect path. The direct connections are always denoted with same numbers like h11 or h22. The indirect components are denoted with combinations of different transmitters, like h12 or h21.
When we combine all the components in one matrix we get Matrix channel or transmission matrix H. Can also be extended for 4x4 LTE MIMO.
When we combine all the components in one matrix we get Matrix channel or transmission matrix H. Can also be extended for 4x4 LTE MIMO.
H = h11 h12
h21 h22
h21 h22
If we characterize the Transmitters as x and Receiver components as Y, we can get our equation for MIMO as
Y = Hx
Adding Guassian Noise and G we will get our final equation.
Y = Hx
Adding Guassian Noise and G we will get our final equation.
This technique supports high data rates. This approach of combining signals allows better resistance against interferers like - multipath, channel fading etc.
Mathematical formula to decide the theoretically equivalent of channel capacity is referred from Shannon- Hartley theorem , discussed below.
Capacity = BW x log2 (1 + SNR)
For MIMO the same equation is going to allow the Capacity to be multiplied by a factor equal to the number of transmitters in the MIMO system.
Mathematical formula to decide the theoretically equivalent of channel capacity is referred from Shannon-
Capacity = BW x log2 (1 + SNR)
For MIMO the same equation is going to allow the Capacity to be multiplied by a factor equal to the number of transmitters in the MIMO system.
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 - AAS and Antenna diversity - AD
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 -
Resources
Verilog RTL code examples for front-end chip design.
Digital Design Topics
Half-adder , full-adder ,
Adder-sub tractor
Stack Organization - LIFO, RPN
Parity Generation and error checking
Binary multiplier circuit.
CMOS introduction
Digital fundamentals -
RTL coding guidelines. ICG cell, Assertions, $assertkill, levels. Chandle
Pipeline vs. Parallel processing.
Verilog RTL code examples for front-
Digital Design Topics
Half-
Adder-
Stack Organization -
Parity Generation and error checking
Binary multiplier circuit.
CMOS introduction
Digital fundamentals -
RTL coding guidelines. ICG cell, Assertions, $assertkill, levels. Chandle
Pipeline vs. Parallel processing.
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MIMO techniques are multi-antenna techniques used in wireless devices to support higher data rates into radio links or RF. MIMO stands for Multiple Input Multiple Output antenna system. A set of mathematical equations are used to determine performance improvements. We will be discussing the 2x2 mimo antenna architecture below.
Interview Questions. Main, FPGA, Digital Fundamentals
More details on LTE MIMO and frame format from here.