Rise-over-Thermal noise level

The Rise-over-Thermal noise level is a measure of the uplink load at the NodeB receiver.

By increasing the number of UEs transmitting on the uplink and their transmit power, the overall level of interference in the uplink band also increases.

 The NodeB receiver perceives this level as noise, and it directly affects the decoding performance of uplink data transmissions.

 The NodeB controls the interference level by adjusting the UE grant assignments according to the current interference level.

 When the UE receives a new grant, it uses it in combination with available UE transmit power and amount of data in the buffer to determine the data rate and the corresponding transmit power.