The basic structure of a 4G LTE frame is designed to efficiently organize the transmission of data over the wireless communication channel. This structured approach allows LTE networks to efficiently manage and schedule transmissions, optimizing the use of available spectrum and accommodating various types of data traffic with different requirements for bandwidth and latency.
A 4G LTE frame consists of the following key components:
Frame Duration: Each LTE frame has a duration of 10 milliseconds (ms), which is the basic time unit in LTE networks.
Subframes: Each LTE frame is divided into 10 subframes, each with a duration of 1 ms. These subframes are the primary units for scheduling data transmission.
Slots: Each subframe is further divided into two slots, each lasting 0.5 ms.
Resource Blocks (RBs): Within each slot, the data is organized into Resource Blocks (RBs). An RB is the smallest unit of resources that can be allocated to a user. It consists of 12 subcarriers in frequency and one slot in time.
Downlink and Uplink Configurations: LTE supports both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) configurations. In FDD, separate frequencies are used for downlink and uplink. In TDD, downlink and uplink transmissions occur on the same frequency but are separated in time, and the frame structure includes special subframes for switching between downlink and uplink.
Special Subframes (for TDD): In TDD configurations, there are special subframes that contain a Downlink Pilot Time Slot (DwPTS) for downlink transmission, a Guard Period (GP) to avoid collision between downlink and uplink transmissions, and an Uplink Pilot Time Slot (UpPTS) for uplink transmission.