A novel RAKE receiver finger number decision rule

RAKE receiver is widely used in wideband code division multiple access (W-CDMA) systems to combat multipath fading. For maximal ratio combining, theoretically, the signal-to-noise ratio (SINR) increases as the number of RAKE receiver fingers increases. However, channel estimation can never be perfect in practice. If we increase improper fingers, the SINR of the added fingers decreases and the channel estimation error increases, which degrades the detection performance. An analytical decision rule for choosing the proper number of RAKE receiver fingers is derived. The decision rule is very simple and can be shown to have optimal SINR for the RAKE receiver.