What is TDD subframe?
In TDD, the transmission is divided into time domain, means at one moment of time either downlink subframe is transmitted or uplink. That has been defined by 3GPP with the name TDD Frame Configurations. There are fixed patterns of these configurations and network operator has to choose out of these defined patters.
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.
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.
What is TDD capacity?
What does this mean for actual capacity? TDD radios claim capacity numbers in half-duplex, meaning the quoted numbers are half in one direction and half in the other. So 1Gbps of capacity is actually 500Mbps transmit and 500Mbps receive since the bandwidth is shared in a TDD system.
How many frame configurations are there in TDD?
In TDD there are about 7 frame configurations, based on different DL/UL partition. Downlink/Uplink ratio can vary from 1/3 (Frame configuration = 0) to 8/1 (Frame configuration = 1). An operator can choose a specific TDD configuration depending on the service requirements
Why do you need special subframe for TDD?
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.
How many subframes are in a type 2 LTE frame?
Type 2: used for the LTE TDD systems. The basic type 1 LTE frame has an overall length of 10 ms. This is then divided into a total of 20 individual slots. LTE Subframes then consist of two slots – in other words there are ten LTE subframes within a frame. The frame structure for the type 2 frames used on LTE TDD is somewhat different.
What is the structure of a LTE FDD 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.
