How MAC Protocol Work In LTE?

The MAC protocol provides the following services:

Logical Channel to Transport channel mapping
Scheduling:
There is no dedicated channel allocated to a UE. Time and frequency resources are dynamically shared between the users in DL and UL. The scheduler is part of the MAC layer and controls the assignment of uplink and downlink resources.
Multiplexing/Demultiplexing of RLC PDU

The scheduler (in the eNodeB) determines dynamically, each 1 ms, which UEs are supposed to receive data on the DL shared channel and on the UL shared channel and on what resources.
The basic time-frequency unit is the resource block.
To select the adapted modulation and coding rate, the scheduler needs measurement reports in DL and UL.

In downlink, the scheduler needs the following inputs to schedule data:

Amount of data
Nature of the data
Radio resource available
Radio Condition in DL The UE reports regularly

its measurement report,called Channel Quality Indicator (CQI).

In uplink, the mechanism is similar but:

Measurements are made by the eNodeB
The eNodeB scheduler controls the UE transmission

Understanding MAC Protocol in LTE

The MAC (Medium Access Control) protocol in LTE controls how data is transmitted between your device (UE) and the network. It helps in scheduling, multiplexing, and managing access to the shared radio channel, ensuring efficient data delivery.

How the MAC Protocol Operates

When you send or receive data, the MAC protocol decides how to organize the data into smaller chunks called transport blocks. It also schedules when your device can transmit, based on the availability of resources from the network. This ensures you’re not overcrowding the network and that everyone gets a fair share of the resources.

Role of Scheduling in MAC

Scheduling is a key function of MAC. It determines the timing and resource allocation for each transmission. Depending on network conditions, your device may be allocated different resources, and MAC ensures those are used efficiently to avoid delays or interruptions in your connection.