In a hardware accelerator for preamble detection of a Physical Random Access Channel (PRACH) in a CDMA based communication system, buffering means stores input samples received at an antenna at a first rate, addressing means read a predetermined consecutive number of the input samples in parallel at a second different rate. The hardware accelerator is further partitioned into a reusable unit providing code correlation, and a preamble detection dedicated unit providing signature code despreading. The reusable unit comprises means for correlating at least a subset of the previously read input samples with a predetermined code to provide a correlation output for a number of time lags. The preamble detection dedicated unit comprises means for preamble detection configured for providing Hadamard Transformation of the correlation output to enable preamble detection, and all means are arranged on a single hardware chip to enable high-speed data transmissions between the respective means.