Wireless relaying has been known to provide the improvements in link reliability, spectral efficiency, and coverage extension. In this paper, we use full duplex relays for Interference Alignment (IA) in K-users Interference Channel (IC) and show K Degrees of Freedom (DOF) is achievable. In first hop, relays receive signals from transmitters and forward them to receivers in second hop. Two iteratively algorithms are proposed for computing relays function, precoder, and decoder matrices. First algorithm minimizes leakage interference at receivers that has appropriate performance at high Signal to Noise Ratio (SNR) region. Furthermore, the second algorithm has better performance at low-mediate SNR. The performance of proposed algorithms are compared with other schemes and validated with simulation in terms of achieved sum rate.
 R. Etkin, D. Tse and H. Wang, “Gaussian Interference Channel Capacity to within One Bit,” IEEE Transaction on Information Theory, Vol. 54, No. 12, 2007, pp. 5534-5562. doi:10.1109/TIT.2008.2009807
 X. Shang, G. Kramer and B. Chen, “A New Outer Bound and the Noisy-Interference Sum-Rate Capacity for Gaussian Interference Channels,” IEEE Transaction on Information Theory, Vol. 55, No. 2, 2009, pp. 689-699. doi:10.1109/TIT.2008.2009793
 V. Cadambe and S. Jafar, “Interference Alignment and the Degrees of Freedom of the k User Interference Channel,” IEEE Transaction on Information Theory, Vol. 54, No. 8, 2008, pp. 3425-344. doi:10.1109/TIT.2008.926344
 M. A. Maddah-Ali, A. S. Motahari and A. K. Khandani, “Communication over MIMO X Channels: Interference Alignment, Decomposition, and Performance Analysis,” IEEE Transactions on Information Theory, Vol. 54, No. 8, 2008, pp. 3457-3470. doi:10.1109/TIT.2008.926460
 K. Gomadam, V. R. Cadambe and S. A. Jafar, “A Distributed Numerical Approach to Interference Alignment and Applications to Wireless Interference Networks,” IEEE Transaction on Information Theory, Vol. 57, No. 6, 2011, pp. 3309-3322. doi:10.1109/TIT.2011.2142270
 C. M. Yetis, T. Gou, S. A. Jafar and A. H. Kayran, “On Feasibility of Interference Alignment in MIMO Interference Networks,” IEEE Transactions on Signal Processing, Vol. 58, No. 9, 2010, pp. 4771-4782.
 V. R. Cadambe and S. A. Jafar, “Can Feedback, Cooperation, Relays and Full Duplex Operation Increase the Degrees of Freedom of Wireless Networks?” IEEE International Symposium on Information Theory, Toronto, 6-11 July 2008, pp. 1263-1267.
 B. Nourani, S. A. Motahari and A. K. Khandani, “Relay-Aided Interference Alignment for the Quasi-Static X Channel,” IEEE International Symposium on Information Theory, Seoul, 28 June 2009-3 July 2009, pp. 1764-1768.
 S. W. Jeon, S. Y. Chung and S. A. Jafar, “Degrees of Freedom of Multi-Source Relay Networks,” 47th Annual Allerton Conference on Communication, Control, and Computing, 30 September-2 October 2009, pp. 388-393.
 A. S. Motahari, S. Oveis Gharan, M. A. Maddah-Ali and A. K. Khandani, “Real Interference Alignment: Exploiting the Potential of Single Antenna Systems” IEEE Transactions on Information Theory, 2009. http://arxiv.org/abs/0908.2282
 H. Ning, C. Ling and K. K. Leung, “Relay-Aided Interference Alignment: Feasibility Conditions and Algorithm,” IEEE International Symposium on Information Theory, Austin, 13-18 June 2010, pp. 390-394.
 H. Al-Shatri and T. Weber, “Interference Alignment Aided by Non-Regenerative Relays for Multi-User Wireless Networks,” Proceeding of 8th International Symposium on Wireless Communication Systems, Aachen, 6-9 November 2011, pp. 271-275.