Time-hopped ultrawide bandwidth receiver designs using multiuser interference sensing

The uncoordinated nature of impulse radio ultrawide bandwidth (UWB) transmissions leads to multiple-user interference (MUI) at each receiver. Due to use of a repetition code and multipath propagation, a Rake receiver has many partial decision statistics available for use in forming a symbol decision. Novel time-hopped UWB Rake receiver structures have been designed that aim to mitigate MUI by sensing the presence of MUI in the partial decision statistics associated with each received symbol. The presented IS method responds to mistimed pulses arising from interfering users for each repeated pulse (frame) of the symbol, in each Rake finger, yielding a signal that is correlated with signals from interfering users but uncorrelated with the desired-user signal. Receivers are presented that use MUI-sensing in selection of the best received pulses for combining, i.e., pulses less likely to be catastrophically corrupted by a pulse due to an interfering user. Also considered are nonlinear receiver structures in which MUI-sensing is used to select a subset of partial decision statistics to undergo nonlinear processing and/or combining.