Noise estimation for multiuser multi-carrier PUCCH in LTE-A

In Long Term Evolution (LTE) system, PUCCH — Physical Uplink Control Channel-is responsible for transmission of the control information from the user equipment (UE) to the base station (eNodeB). PUCCH introduced a new format — format 3 — to accommodate the increase of Hybrid Automatic Repeat request (HARQ) bits resulting from Multi-carrier transmission. This format suffers from poor noise estimation accuracy problem that affects the detection probability and degrades the whole system throughput. Two independent algorithms for noise estimation are introduced in this paper for CDMA multiuser multicarrier PUCCH format 3. The first algorithm is based on noise detection from data symbols, while the second algorithm is based on noise estimation from pilot symbols. Simulation results showed the accuracy of noise estimation in both algorithms in the presence of multipath fading channels.