Reconfigurable antennas for performance enhancement of interference networks employing interference alignment
By using reconfigurable antenna based pattern diversity, an optimal channel can be realized in order to maximize the distance between two subspaces, thereby increasing sum-rate. The inventors show the benefits of pattern reconfigurability using real-world channels, measured in a MIMO-OFDM interference network. The results are quantified with two different reconfigurable antenna architectures. An additional 47% gain in choral distance and 45% gain in sum capacity were achieved by exploiting pattern diversity with IA. Due to optimal channel selection, the performance of IA can also be improved in a low SNR regime.
1. A system with increased sum capacity for k users, k>1, of an interference network employing interference alignment as the interference management scheme, said system comprising a plurality of reconfigurable antennas that offer pattern diversity, said plurality of reconfigurable antennas implementing said interference alignment scheme, wherein an interference channel between a first reconfigurable antenna and a second reconfigurable antenna is optimized to maximize a distance between interference and desired signal space.
2. The system of claim 1 , wherein the interference network comprises a MIMO OFDM interference network.
3. The system of claim 1 , wherein at least one of said reconfigurable antennas comprises a reconfigurable printed dipole array (RPDA).
4. The system of claim 1 , wherein at least one of said reconfigurable antennas comprises a reconfigurable circular patch array (RCPA).
5. The system of claim 1 , wherein said plurality of reconfigurable antennas have multiple antenna states of operation corresponding to multiple radiation patterns at all receivers and transmitters and at least one of said reconfigurable antennas is configured to have an optimal antenna state to enhance total chordal distance between interference and signal subspaces so as to improve sum capacity performance of the interference network.
6. The system of claim 1 , wherein at least one of said reconfigurable antennas comprises a closed form interference alignment precoder and another one of said reconfigurable antennas comprises a closed form interference alignment decoder.
7. A method of increasing the sum capacity for k users, k>1, of an interference network employing interference alignment as the interference management scheme, comprising the steps of:
transmitting data over an interference channel using a first reconfigurable antenna that offers pattern diversity for interference alignment over the interference channel; and
optimizing the interference channel between said first reconfigurable antenna and a second reconfigurable antenna to maximize the distance between interference and desired signal space.
8. The method of claim 7 , wherein the interference network comprises a MIMO OFDM interference network and transmitting data over an interference channel comprises transmitting data over an interference channel of said MIMO OFDM interference network.
9. The method of claim 7 , wherein said optimizing step comprises selecting an optimal antenna state for at least one of said first and second reconfigurable antennas to enhance total chordal distance between interference and signal subspaces so as to improve sum capacity performance of the interference network.
10. The method of claim 7 , further comprising one of said first and second reconfigurable antennas precoding data for OFDM transmission using a closed form interference alignment precoder and said second reconfigurable antenna decoding received data using a closed form interference alignment decoder.