What is special subframe in TDD?

Special subframe Details TDD duplex mode needs to switch transmission from Downlink to Uplink and Uplink to Downlink, hence Special subframe is required for switching the transmission from Downlink to Uplink. In TDD, there are two periodicity frame one with 5ms periodicity and another with 10 ms periodicity.

What is a subframe in LTE?

In LTE, DL and UL transmissions are organized into radio frames of 10 ms each. Each frame is divided into ten equally sized subframes. The duration of each subframe is 1 ms. Moreover, each subframe is further divided into two equally sized time slots, that is, each slot is 0.5 ms.

What is TDD configuration?

3-5/6/7 is not supported for TDD UL/DL configuration 5….

Features	FDD	TDD
HARQ Timing	K = 4 (fixed) DL : Async, UL :Sync	K = varying depending on Subframe Config DL : Async, UL : Sync
Ack/Nack Feedback Mode	One Transmission one Ack/Nack	Bundling or Multiplexed
SR/DCI 0 Timing	4 ms	Varying
DCI 0/PUSCH Timing	4 ms	Varying

What is the difference between the LTE FDD and TDD frame structures?

Let us understand LTE FDD and TDD LTE versions with figures and band example below. LTE has radio frame of duration 10ms consisting of 10 subframes. Each subframe has two slots. The slot is of 0.5ms duration….TDD LTE.

Feature	LTE FDD	TDD LTE
Frame structure	Uses FDD frame structure	Uses TDD frame structure, READ MORE

What is TDD in LTE?

Nevertheless, TDD LTE (also known as TD LTE) stands for Time Division Duplexing-Long Term Evolution. FDD LTE stands for Frequency-Division Duplexing LTE. Both TDD and FDD differ in the way they treat data. Duplexing means a phone can transmit and receive simultaneously.

How does a UE identify that eNodeB is configured for TDD or FDD?

The possition, where PSS & SSS signals are transmitted, is different for FDD and TDD mode. During cell search the LTE UE has to locate & receive these signals. This is how the LTE UE knows whether the LTE cell is TDD or FDD cell. After detection of location of SSS with respect to PSS, UE distinguish about FDD and TDD..

How many symbols does a subframe have?

Each of sub frame consists of 2 slots, each of which is 0.5 ms in length. Each of slots consists of 7 symbols, each of which is 66.7 us.

How many HARQ process in LTE TDD?

There are 8 uplink HARQ processes running on both UE and eNB with 4 processes delay. HARQ process length is same as a subframe (1 ms). When UE sends data to eNB, eNB decodes data and checks CRC. eNB then sends acknowledgement (ACK) or not-acknowledged (NACK) to UE after 4 subframes.

What is LTE FDD TDD?

FDD LTE stands for Frequency-Division Duplexing LTE. Both TDD and FDD differ in the way they treat data. Duplexing means a phone can transmit and receive simultaneously. TDD means the “receive” and “transmit” channels divide the time between them on the same frequency band.

Which is better LTE FDD or TDD?

In general, FDD is considered better for coverage and TDD better for capacity. Mobile operators are looking to carrier aggregation (CA), which allows them to use multiple sub-6 GHz spectrum channels simultaneously, as a method of increasing the bandwidth and speeds of their 5G networks.

Which is faster TDD or FDD?

Theoretical peak throughput in case of FDD is clearly better than TDD. TDD has less capacity to accommodate user data and traffic in radio frame compared to FDD.

How does UE connect to eNodeB?

UE establishes the RRC Connection with the eNodeB. 2. The UE sends the ATTACH REQUEST message together with a PDN CONNECTIVITY REQUEST for the PDN (IP) connectivity on the established RRC Connection. As part of this, the eNodeB establishes the S1 logical connection with the MME for this UE.

What are the special Subframe configuration in TDD?

In TDD , there are 9 special subframe configuration, each have different number of OFDM symbols for DwPTS,GP and UpPTS. Special subframe guard period impact the size of cell, it represent how much propagation delay it can compensate.

What is the frame configuration for LTE TDD?

LTE TDD Frame Configuration These first three groups of settings apply to all basic carriers. The Fading parameters are available for Advanced LTE and Advanced LTE-A TDD carriers only. Some parameters do not apply to the Basic LTE PRACH and Basic LTE-A PRACH.

How many subframes are there in an LTE frame?

There are total 10 subframes in a frame. Each subframe composed of 2 time slots. Type 1 is used as LTE FDD frame structure. As shown in the figure below, an LTE TDD frame is made of total 20 slots, each of 0.5ms. Two consecutive time slots will form one subframe. 10 such subframes form one radio frame.

What is DL and UL configuration in LTE frame structure?

The table mentions DL and UL configuration which determines the contents of the subframes in LTE frame structure. In the table, ‘U’ stands for Uplink, ‘D’ stands for Downlink and ‘S’ stands for special subframe.