Flow control is a mechanism used to regulate the rate of data transmission between two entities in a communication network. In the context of LTE, flow control is implemented by the Radio Resource Control (RRC) protocol to prevent buffer overflows and to ensure efficient use of radio resources.
While flow control can help prevent buffer overflows and other issues, it can also decrease DL throughput if not properly optimized. Some examples of flow control mechanisms that can decrease DL throughput include:
Window-based flow control: In window-based flow control, the sender is only allowed to send a certain number of packets before waiting for an acknowledgement from the receiver. If the window size is too small, it can limit the amount of data that can be transmitted at once and decrease throughput.
Rate-based flow control: In rate-based flow control, the sender is only allowed to send data at a certain rate. If the rate is too low, it can limit the amount of data that can be transmitted and decrease throughput.
Packet-based flow control: In packet-based flow control, the sender is only allowed to send a certain number of packets before waiting for an acknowledgement from the receiver. If the packet size is too small, it can lead to increased overhead and decrease throughput.
To optimize flow control and minimize its impact on DL throughput, it is important to properly configure the flow control mechanisms based on the network conditions and requirements. This may involve adjusting the window size, rate, or packet size, as well as implementing advanced flow control mechanisms such as selective acknowledgements or congestion control algorithms. Additionally, the use of advanced radio technologies such as carrier aggregation and MIMO can help increase DL throughput by providing more available radio resources and improving signal quality.