What are the LTE physical layer design requirements?
The design of the LTE physical layer (PHY) is heavily influenced by requirements for high peak transmission rate (100 Mbps DL/50 Mbps UL), spectral efficiency, and multiple channel bandwidths (1.25-20 MHz).
What are logical transport and physical channels?
Physical channels: These are transmission channels that carry user data and control messages. Logical channels: Provide services for the Medium Access Control (MAC) layer within the LTE protocol structure.
What QAM is used in LTE?
Just what is QAM-256? It refers to Quadrature Amplitude Modulation, which is the means by which a carrier signal, such as an LTE waveform, transmits data and information. Ideally, a waveform/symbol carries as much data as possible in order to achieve higher data rates and increase spectral efficiency.
What is PDCP layer in LTE?
PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer. PDCP provides its services to the RRC and user plane upper layers, e.g. IP at the UE or to the relay at the base station.
What is physical channel in LTE?
What are the physical channels?
Physical channels correspond to sets of time-frequency resources used for transmission of particular transport channel data, control information, or indicator information. Each transport channel is mapped to a corresponding physical channel.
What is OFDMA and MU MIMO?
OFDMA stands for Orthogonal Frequency Division Multiple Access. MU-MIMO stands for Multi-user multiple-input and multiple-output. Also known as Multi-user MIMO. Both of these multi-user technologies are significant technical enhancements that come with Wi-Fi 6.
How is PRB calculated in LTE?
Physical Resource Block (PRB) = 2*Resource Block = 12 Subcarriers x 14 OFDM in 1ms.
What is TM3 and TM4 in LTE?
What we normally call ‘Diversity’ is called ‘TM2’. What we call ‘MIMO’ but no feedback from UE is called ‘TM3’. MIMO and UE feedback from UE (CQI, PMI, RI) is called ‘TM4’. A good summary of each Transmission Mode can be as following table from 36.213. These table ecolved and got more complicated as LTE evolves.
Does LTE support 256 QAM?
“In both wireless and wireline communications, there is 16-QAM, 64-QAM, and 256-QAM, which all pertain to LTE, as well as even higher QAM schemes, such as 1024-QAM, which are now being considered for the future evolution of LTE/LTE-Advanced Pro and 5G.”
What is the difference between physical and logical channels?
The Physical channels are determined by the timeslot, whereas the logical channels are determined by the information carried within the physical channel. It can be further summarised by saying that several recurring timeslots on a carrier constitute a physical channel.