RBs resource blocks

Resource Blocks (RBs) are a fundamental concept in wireless communication systems, particularly in cellular networks like Long-Term Evolution (LTE) and 5G New Radio (NR). RBs represent the basic unit of resource allocation in the time-frequency domain.

RBs are used to divide the available radio resources, such as frequency bands and time slots, into smaller chunks that can be allocated to individual users or communication channels. The allocation of RBs is managed by the base station (eNodeB in LTE or gNodeB in 5G NR) and is based on the network's scheduling algorithm and the quality of service (QoS) requirements of the users.

RBs are typically defined in the frequency-time grid, where the frequency axis represents the available frequency bands, and the time axis represents the available time slots. The size of an RB can vary depending on the specific system and configuration. In LTE, an RB consists of 12 consecutive subcarriers in the frequency domain and one time slot in the time domain. The subcarrier spacing defines the frequency spacing between the individual subcarriers within an RB.

In 5G NR, the concept of RBs has evolved to be more flexible and adaptable to different deployment scenarios and channel conditions. 5G NR introduces the concept of numerology, which allows for different subcarrier spacing options. Depending on the numerology, the size of an RB can vary. For example, in a subcarrier spacing of 15 kHz, an RB may consist of 12 subcarriers in the frequency domain and one time slot in the time domain, similar to LTE. However, in a subcarrier spacing of 60 kHz, an RB may consist of 4 subcarriers and one time slot.

RBs serve as the basic building blocks for resource allocation and scheduling. They are allocated to users based on their communication requirements and the network's scheduling policies. RB allocation takes into account various factors, including the channel conditions, user priority, QoS requirements, and the system's overall resource availability. The base station allocates RBs to users in a dynamic manner, considering the changing channel conditions and the real-time traffic demands.

RBs provide a convenient and efficient way to allocate radio resources in a cellular network. They allow for flexible resource management, enabling the base station to allocate resources according to the specific needs of each user or communication channel. By dividing the available resources into smaller RBs, it becomes possible to efficiently utilize the limited spectrum and time slots, ensuring fair and optimal resource allocation across multiple users in the network.