How to LTE Radio Air Interface?
The state-of-the-art design of the LTE air interface is characterised by OFDMA (DL) and SC-FDMA (UL) together with MIMO. The downlink modulation is based on OFDMA (Orthogonal Frequency Division Multiple…
Tag: harq
LTE Frame Structure and Resource Block Architecture
LTE Frame Structure The figure below shows the LTE frame structure under Time division mode (TDD) Type 2 and Frequency Division mode (FDD) Type 1. Differences in LTE Frame Structure…
What is AMC & its Algorithm in LTE
The effective Eb/No and hence the spectral efficiency depend on BLER. However there are QoS requirements which also have to be considered. Taking both into account leads to a target…
BENEFITS OF LTE/EPC
Fully packet-oriented mobile broadband network providing: – Peak data rates of 100 Mbps (DL) and 50 Mbps (UL) – Very low latency – Seamless and lossless handover – Sophisticated QoS…
LTE Downlink & Uplink Physical Channel
LTE Downlink Physical Channel Physical Downlink Shared Channel ( PDSCH) This channel is used for unicastand paging functions. Carries the DL-SCH and PCH. QPSK,16-QAM,and 64-QAM Modulation. Physical Downlink Control Channel…
Synchronization of signals in LTE
504 different physical-layer cell ids are composed of 168 different physical-layer cell id groups each of 3 physical layer ids within the group There are – primary synchronization signal –…
H-ARQ Mechanism in DL
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…
what is Radio Retransmission in LTE?
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…
What is Correlation in CDMA ?
Correlation Is a Measure of How Well a Given Signal Matches a Desired Code, The Desired Code is Compared to the Given Signal at Various Test times. Correlation is key…
Function of Control plane protocol stacks in LTE
The control plane includes the application protocol. It also includes the signaling bearers for transporting the application protocol messages. The application protocol is used for setting up bearers in the…
UL and DL cell based scheduler
The scheduling is performed on cell basis. The two main functions are to decide which UE(s) shall be scheduled, the number of resources and the MCS to be applied. Furthermore…
Hybrid ARQ (HARQ) in LTE
Hybrid ARQ (HARQ) leads to higher efficiency in transmission and error correction. There is one HARQ entity per UE with 8 stop-and-wait processes for each HARQ entity. Both incremental redundancy…