A study on the optimal degree-of-freedoms of cellular networks: Opportunistic interference mitigation

We introduce an opportunistic interference mitigation (OIM) protocol for cellular networks, where a user scheduling strategy is utilized in uplink K-cell environments with time-invariant channel coefficients and base stations (BSs) having M receive antennas. In the OIM scheme, each BS opportunistically selects a set of users who generate the minimum interference to the other BSs. We consider two OIM protocols according to the number S of simultaneously transmitting users per cell. Then, their performance is analyzed in terms of degrees-of-freedom (DoFs). As our main result, it is shown that KS DoFs are achievable if and only if the total number N of users in a cell scales at least as SNR(K−1)S. These results indicate that there exists a trade-off between the achievable number of DoFs and the scaling parameter N by tuning the number S of selected users. By showing an upper bound on the DoFs, it is also shown that the OIM scheme with M selected users is DoF-optimal. Finally, numerical evaluation is performed.

[1]  Sae-Young Chung,et al.  Improved Power-Delay Trade-off in Wireless Networks Using Opportunistic Routing , 2009, ArXiv.

[2]  Syed Ali Jafar,et al.  Interference Alignment and Degrees of Freedom of the $K$-User Interference Channel , 2008, IEEE Transactions on Information Theory.

[3]  Alexander M. Haimovich,et al.  Opportunistic Relaying in Wireless Networks , 2007, IEEE Transactions on Information Theory.

[4]  Changho Suh,et al.  Interference Alignment for Cellular Networks , 2008, 2008 46th Annual Allerton Conference on Communication, Control, and Computing.

[5]  Syed Ali Jafar,et al.  Degrees of Freedom of the K User M×N MIMO Interference Channel , 2008, ArXiv.

[6]  David Tse,et al.  Sum capacity of the vector Gaussian broadcast channel and uplink-downlink duality , 2003, IEEE Trans. Inf. Theory.

[7]  Donald E. Knuth,et al.  Big Omicron and big Omega and big Theta , 1976, SIGA.

[8]  Bang Chul Jung,et al.  Opportunistic Interference Mitigation Achieves Optimal Degrees-of-Freedom in Cellular Networks , 2010, ArXiv.

[9]  Syed Ali Jafar,et al.  Degrees of Freedom of the K User M times N MIMO Interference Channel , 2008, IEEE Trans. Inf. Theory.

[10]  Lizhong Zheng,et al.  Diversity and multiplexing: a fundamental tradeoff in multiple-antenna channels , 2003, IEEE Trans. Inf. Theory.

[11]  David Tse,et al.  Opportunistic beamforming using dumb antennas , 2002, IEEE Trans. Inf. Theory.

[12]  Amir K. Khandani,et al.  Communication Over MIMO X Channels: Interference Alignment, Decomposition, and Performance Analysis , 2008, IEEE Transactions on Information Theory.

[13]  Michael Gastpar,et al.  Ergodic Interference Alignment , 2012, IEEE Trans. Inf. Theory.

[14]  Syed Ali Jafar,et al.  Approaching the Capacity of Wireless Networks through Distributed Interference Alignment , 2008, IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference.

[15]  Robert W. Heath,et al.  Opportunistic Feedback for Multiuser MIMO Systems With Linear Receivers , 2007, IEEE Transactions on Communications.

[16]  Babak Hassibi,et al.  On the capacity of MIMO broadcast channels with partial side information , 2005, IEEE Transactions on Information Theory.

[17]  Raymond Knopp,et al.  Information capacity and power control in single-cell multiuser communications , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[18]  Shlomo Shamai,et al.  Degrees of Freedom Region of the MIMO $X$ Channel , 2008, IEEE Transactions on Information Theory.

[19]  Syed Ali Jafar,et al.  Degrees of freedom of wireless X networks , 2008, 2008 IEEE International Symposium on Information Theory.

[20]  Sae-Young Chung,et al.  Improved Power-Delay Trade-off in Wireless Ad Hoc Networks Using Opportunistic Routing , 2007, 2007 IEEE International Symposium on Information Theory.

[21]  S. Jafar,et al.  Degrees of freedom of the K user MIMO interference channel , 2008, 2008 42nd Asilomar Conference on Signals, Systems and Computers.

[22]  David Tse,et al.  Fundamentals of Wireless Communication , 2005 .

[23]  Michael P. Fitz,et al.  Opportunistic Spatial Orthogonalization and its application in fading cognitive radio networks , 2009 .