Achievable improvement of signal quality using rake reception was evaluated for ultrawideband impulse-radio and spread-spectrum systems. The evaluation was based on extensive area propagation measurement in a line-of-sight office environment. Influence of large- and small-scale propagation behavior on improvement of receiving signal-to-noise ratio (SNR) was analyzed. The analyses revealed that having eight fingers could achieve sufficient improvement of receiving SNR under practical conditions. It was also demonstrated that eight-finger rake reception could extend service coverage and reduce outage probability.