Extending the scope of 802.11 WLAN through LMMSE CDMA receiver structures

This paper describes the performance of an LMMSE receiver which has been adapted to operate according to the IEEE 802.11 2.4 GHz wireless LAN (WLAN) standard. The LMMSE receiver offers significant theoretical advantages in terms of interference suppression, ability to operate in substantially time-dispersive environments, and operation in non-line of sight conditions. These advantages combine to offer much greater link distances than conventional RAKE + equalizer receiver structures when applied to the short spreading ratio direct sequence spread spectrum (DSSS) WLAN standard. The prototype which has been constructed offers performance very close to the theoretical limits of the receiver whilst operating in 802.11 mode, as well as offering a higher speed proprietary mode.