Single User and Multi User MIMO codewords in LTE

Single User and Multi User MIMO codewords in LTE Figure shows how the two codewords are used for a single user in the downlink. It is also possible that the code words to be assigned to different users to create multi-user MIMO (MU-MIMO). Depending on the channel information available in the eNB, modulation and precoding … Read more

Codeword, layer, and precoding in LTE

Codeword, layer, and precoding in LTE Terms codeword, layer, and precoding have been taken to refer specifically to LTE signals and processing. The figure shows the processing steps to which they relate. The terms used in the following ways: Codeword: codeword represents the user data before it is formatted for transmission. One or two code … Read more

The MIMO channel Matrix

The MIMO channel Matrix Consider for a moment in time, on the same frequency and channel modeling as a black box with durable internal components. If we add two completely different input signals is to be mixed with each other in a certain manner depending on the value of Z1 to Z4. If we send … Read more

Multi-antenna Techniques LTE to improve the downlink performance

Multi-antenna Techniques LTE to improve the downlink performance There are five methods of multiple antennas have been defined for the LTE downlink to improve the performance: Receive diversity at the mobile Transmit diversity using SFBC at the eNB (evolved Node B) MIMO spatial multiplexing at the eNB, for one or two users Cyclic Delay Diversity … Read more

LTE MIMO Types of Inputs and Outputs

LTE MIMO Types of Inputs and Outputs LTE MIMO “input” and “output” are used for medium between transmitters and receivers, including both RF components – known as the “channel”. Thus, the base station with two transmitters provides two inputs to the channel, “mi” page, and the handset takes two strings get two out of the … Read more

How Non Access Stratum procedures works in LTE

The procedures for the Non Access Stratum, especially power management procedures are substantially similar to UMTS. Main change is that the UMTS EPS allows concatenation certain procedures to allow faster creation of connection and media. Create MME UE context, when the UE is on and attaches to the network. Assign a unique ID called SAE … Read more

Spatial Multiplexing and Receiver Gains in Wimax

Spatial Multiplexing In a multipath environment, the data rate increase due to MIMO is equal to the number of MIMO antennas. Rather than to transmit the same bit of more than two antennas, the Spatial Multiplexing method sends a data bit from the first antenna, and another bit of the second antenna at the same … Read more

Receive Diversity Selection and Switched Diversity

Make use of a number of receive antennas that are well separated (coherence distance) to generate independent receptions of the transmitted signal. Selection diversity: choose received signal with largest received power, S/N, etc. Switched diversity: choose alternate antenna if signal falls below a certain threshold. Linear combining: linearly combine a weighted replica of all received … Read more