LTE Parameters and Downlink Modulation LTE (Long-Term Evolution) utilizes various parameters and downlink modulation schemes to optimize data transmission over the wireless network. LTE parameters and frequency bands What is OFDMA? OFDMA multiple access and downlink frame structure OFDMA transmit and receive chains Here are some important parameters and downlink modulation techniques used in LTE: … Read more
Transmit Diversity MISO = Multiple Input Single Output Principle More complex than SISO. 2 or more transmitters and one receiver. MISO is more commonly referred to as transmit diversity. The same data is sent on both transmitting antennas but coded in such a way that the receiver can identify each transmitter. Benefits Transmit diversity increases … Read more
1. The Transport block is transmitted to the UE on the PDSCH. 2. The UE receives it but it is erroneous. The TB is stored in a buffer. 3. The UE transmits directly a NACK concerning the erroneous block on the PUCCH. One HARQ entity in the UE and the e-UTRAN Made of 8 HARQ … Read more
The radio retransmission mechanism is called Hybrid Automatic Request (H-ARQ). H-ARQ allows to retransmit fastly erroneous blocks between the eNodeB and the UE. It avoids long retransmission between 2 TCP layers. The H-ARQ process runs in the eNodeB and in the UE. The H-ARQ is based on ACK/NACK messages carried by PUCCH or PUSCH. The … Read more
The use of multiple antenna technology allows the exploitation of the spatial domain as another new dimension. This becomes essential in the quest for higher spectral efficiencies With the use of multiple antennas the theoretically-achievable spectral efficiency scales linearly with the minimum of the number of transmit and receive antennas employed, at least in suitable … Read more