Experimental Investigation of Sampling Rate Selection with Fractional Sampling for IEEE802.11b WLAN System

In a direct-sequence / spread-spectrum (DS/SS) system, a RAKE receiver is used to improve a bit error rate (BER) performance. The RAKE receiver can collect more signal energy through independent paths and achieve path diversity. The RAKE receiver obtains further diversity gain through fractional sampling. However, the power consumption of the RAKE receiver increases in proportion to a sampling rate and does not always maximize the signal-to-noise ratio (SNR). Therefore, the sampling rate selection schemes have been proposed to reduce the average sampling rate without degrading the BER. These schemes select the tap positions and the sampling rate depending on channel conditions. In this paper, sampling rate selection schemes for the DS/SS system are investigated through an experiment. Numerical results show that the power consumption can be reduced even through the experiment without the degradation of the BER.