Wireless-system designers are faced with numerous challenges, including limited availability of radio-frequency spectrum and transmission problems caused by such factors as fading and multipath distortion. Meanwhile, there is increasing demand for higher data rates, better-quality service, fewer dropped calls, and higher network capacity. Meeting these needs requires new techniques that improve spectral efficiency and network links operational reliability. Multiple-input-multiple-output technology promises a cost-effective way to provide these capabilities. MIMO uses antenna arrays at both the transmitter and receiver. Algorithms in a radio chipset send information out over the antennas. The radio signals reflect off objects, creating multiple paths that in conventional radios cause interference and fading. But MIMO sends data over these multiple paths, thereby increasing the amount of information the system carries. The data is received by multiple antennas and recombined properly by other MIMO algorithms. This technology promises to let engineers scale up wireless bandwidth or increase transmission ranges.