Reconfigurable Subaperturing for Endo-clutter Processing

The objective of the current Phase II proposal is to develop methods for generating dynamically reconfigurable subaperture architectures for enhanced clutter/interference suppression and performing multiple tasks using distributed multi-sensor (MIMO) technology.  For the purpose of clutter nulling, transmitter adaptivity using smart subarray beamforming, together with adaptive interference  nulling algorithms at the receiver side are envisioned both in the slow-time as well as the fast-time domain. Using output signal to interference/jammer plus noise ratio (SINR) as an optimization strategy, for a given transmit waveform, the adaptive receiver is given by the generalized matched filter that whitens the total interference/noise scene and matches to the incoming target signal. This leads to an SINR that is still a function of the transmit waveform pattern. Additional optimization can be carried out to maximize the receiver-optimized SINR output over the transmit waveform in the fast-time.  By making use of the array output power a new strategy is proposed here to dynamically reconfigure the array so that the return signals are tailored to the desired scene, and for generating a transmit pattern together with an adaptive receiver  to effectively null out the endo-clutter effects and perform multiple tasks. BENEFITS: Our experience in space time adaptive processing puts us in a position to develop and provide high-performance digital signal-processing algorithms that will suppress interferences, allowing a higher number of users and applications that demand higher data rates. Joint transmitter-receiver design in the slow-time and fast time allows dynamic interference suppression and anticipated interference nulling thus enhancing channel quality  while generating quality multiple beams for communication purposes.  One important area of this class of signal processing is adaptive space-time  processing also known as smart antenna processing. By incorporating adaptive signal processing algorithms and waveform diversity, smart antenna processing can be performed automatically to all users within a cellular/CDMA system. The resulting system will have a substantial increase in isolation between users at all times, allowing an effective increase in capacity and an increase in the total number of users. Translating this approach into the wireless/cellular communication would add more channels that can be packed into the existing bandwidth thus increasing throughput.