What is LTE Pdsch?
In LTE the Downlink Shared Channel (DL-SCH) is a transport channel used for the transmission of user data, dedicated control and user-specific higher layer information and downlink system information. The Physical Downlink Shared Channel (PDSCH) is the physical channel that carries the DL-SCH coded data.
How many codewords are there in LTE?
There are two codewords defined for LTE: CW0 and CW1. Every channel uses CW0. PDSCH (user data) has the option of using CW1. Also, CW1 is only available when using spatial multiplexing.
What will happen if Pdsch is not decoded correctly?
The PDCCH will tell the UE that the data it is looking for is located at this location on PDSCH. This means that if the UE is unable to decode PDCCH then the UE cannot read the PDSCH in that subframe and consistent decoding failures of PDCCH lead to RLF (Radio Link Failure) due to N310.
What is Pdcch and Pdsch?
PDSCH — physical downlink shared channel. The PDSCH carries user data and paging information to the terminal. PDCCH — physical downlink control channel. The PDCCH conveys control information, scheduling decisions for PDSCH reception, and for scheduling grants enabling transmission on the PUSCH.
How many channels are there in LTE?
three different channel
There are three different channel types defined in LTE—logical channels, transport channels, and physical channels, each associated with a service access point (SAP) between different layers. These channels are used by the lower layers of the protocol stack to provide services to the higher layers.
How does LTE communication channels work?
The information flows between the different protocols are known as channels and signals. LTE uses several different types of logical, transport and physical channel, which are distinguished by the kind of information they carry and by the way in which the information is processed.
Why are there 12 subcarriers in LTE?
In the downlink, the subcarriers are split into resource blocks. This enables the system to be able to compartmentalise the data across standard numbers of subcarriers. Resource blocks comprise 12 subcarriers, regardless of the overall LTE signal bandwidth. They also cover one slot in the time frame.
How many codewords are used in 4×4 MIMO?
2 Codeword
4 x 2 MIMO, 2 Layer, 2 Codeword
(4) Channel Path/Fading : you can get the general concept of Channel Path by refering to Channel Modeling page and refer to Fading page to understand how to derive channel correlation matrix.
What is the reason for poor CQI in LTE?
b) If low CQI values are found after a CQI report is obtained, then downlink interference might be the cause of low throughput. a) Run a report for BLER in the cells identified. The BLER should be smaller or equal than 10%. If the value is larger, then, there is an indication of bad RF environment.
How increase IP throughput in LTE?
The easiest way is to give a higher priority to L1800 and that will shift most of the UEs in L1800 coverage away from L800. This will ensure better CQI for users and thus a better throughput. Another way would be to keep them on same priority and provide a frequency offset to move the users to L1800.
Where is Pdcch located?
The PDCCH is located in the first few OFDM symbols of a subframe. For frame structure Type 2, PDCCH can also be mapped to the first two OFDM symbols of the DwPTS field.
What information Pdcch carries?
The PDCCH carries scheduling assignments and other control information in the form of DCI messages. A PDCCH is transmitted on one CCE or an aggregation of several consecutive CCEs, where a CCE corresponds to 9 Resource Element Groups (REGs).
What is an LTE channel?
LTE uses a series of data channels to provide effective management of the data: physical, logical and transport channels are used. These LTE channels provide different interfaces into the higher layers of the protocol stack and in this way they are able to provide efficient management of the data.
What are layers in LTE?
LTE Protocol Stack Layers
- Physical Layer (Layer 1) Physical Layer carries all information from the MAC transport channels over the air interface.
- Medium Access Layer (MAC)
- Radio Link Control (RLC)
- Radio Resource Control (RRC)
- Packet Data Convergence Control (PDCP)
- Non Access Stratum (NAS) Protocols.
Is LTE the same as 4G?
So what’s the difference between 4G and LTE, and is 4G or LTE better? In short, 4G offers a much faster speed, more stability and access to a larger variety of online activities. LTE is a half-point between 3G and 4G, so its performance suffers compared to the fourth generation.
How many RBs is 20Mhz?
100 RBs
In case of 20Mhz with 100 RBs, then the maximum bit rate will be double of that which i calculated, that is 100.8Mb/s, For 50 Mbls one has to assign x blocks= (50/100.8)x total no. of resource blocks(100)= one has to assign 50 resource blocks, and in case of 60 Mbls the number of assigned RBs= (60/100.8) 100=60.
How many subcarriers are in 5G?
5G NR can choose subcarrier spacing from 15kHz to 240kHz, with a maximum 3300 subcarriers in simultaneous use on one channel.
Which is the maximum number of codewords for MIMO transmission?
8 x 2 MIMO, 2 Layer, 2 Codeword
(3) Precoding : This is process where the layer data are allocated to multiple antenna ports (logical antenna ports in this stage).
What are layers in MIMO?
Single-user MIMO (SU-MIMO) is the ability to transmit one or multiple data streams, called layers, from one transmitting array to a single user. SU-MIMO can thereby increase the throughput for that user and increase the capacity of the network.
What is a good CQI value?
In HSDPA, the CQI value ranges from 0 ~ 30. 30 indicates the best channel quality and 0,1 indicates the poorest channel quality. Depending which value UE reports, network transmit data with different transport block size.
How do you check CQI LTE?
How to test CQI?
- i) UE sends a CQI report with a certain value (e.g, 15)
- ii) eNB sends PDSCH with the highest MCS (i.e, the highest code rate and the largest transport block)
- iii) If UE can successfully decode it (meaning BLER lower than a certain limit), it sends the same or higher CQI.
What causes low throughput in LTE?
b) If the maximum number of RRC connections active per cell is close or equal to the maximum number of RRC connections supported, then. The cause for low throughput is load.
What affects LTE throughput?
LTE throughput depends on the following parameters: Bandwidth. Channel quality. Network load.
What is DCI and Pdcch?
The Downlink Control Information (DCI) is transmitted through the Physical Downlink Control Channel (PDCCH) and includes information about the DL-SCH resource allocation (the set of resource blocks containing the DL-SCH), transport format and information related to the DL-SCH Hybrid Automatic Repeat reQuest (ARQ).
What is the Pdcch in LTE?
The Physical Downlink Control Channel (PDCCH) is primarily used to carry scheduling information to individual UEs, i.e., resource assignments for uplink and downlink data and control information. The PDCCH is located in the first few OFDM symbols of a subframe.