The technical details of Resource Elements (REs) in wireless communication systems, particularly in cellular networks like LTE (Long-Term Evolution) and 5G.
- Resource Element (RE):
- An RE is the smallest defined unit for allocating time-frequency resources.
- It represents the fundamental granularity at which data or control information is transmitted.
- Each RE corresponds to one OFDM sub-carrier during a single OFDM symbol interval.
- In other words, an RE carries a complex value (amplitude and phase) that contributes to the overall signal.
- REs are essential for efficient resource allocation and modulation/demodulation processes.
- Resource Block (RB):
- An RB consists of a group of consecutive REs in the frequency domain.
- Specifically, an RB in LTE comprises 12 consecutive subcarriers.
- For normal cyclic prefix (CP), an RB contains 84 REs (72 for extended CP).
- These REs are grouped into Physical Resource Blocks (PRBs), each containing 12 subcarriers.
- PRBs are the basic building blocks for resource allocation in LTE.
- Identification of REs:
- Each RE is uniquely identified by its position within the resource grid.
- The index in the frequency domain is denoted by k, and the symbol position in the time domain is denoted by l.
- Thus, an RE is represented as (k, l), where p indicates the antenna port and μ represents the subcarrier spacing configuration.
REs play a crucial role in managing the allocation of resources across time and frequency in cellular networks. They enable efficient data transmission and form the foundation for various communication protocols.
