Resource Element in LTE


Resource Element

A Resource element is the basic unit of Physical Resource in LTE. The UE compete to get more and more resource elements assigned to them in Downlink and Uplink. The number of resource elements assigned is directly proportional to the data rate experienced by the UE.

To understand the operation of Resource Element and its allocation, we start by looking at the Frame Structure

The radio frame(10ms) is divided into 10 sub-frames, each further sub divided into 2 slots(0.5ms each).

Downlink Resource Element

One slot corresponds to 6 or 7 OFDM symbols depending upon Normal or Extended cyclic prefix is in use. The sub-carriers on Y-Axis and the OFDM symbols on X-axis form a Resource Grid, as shown in figure below,


A Resource Block has boundary of NUM_SC sub carriers and NUM_SYMB OFDM symbols. Resource Element is one box in the Resource Block and is represented as indexed pair (k,l), where k = 0 to NUM_SC and l= 0 to NUM_SYMB.