Asynchronous Orthogonal Differential Decoding for Multiple Access Channels

We propose several differential decoding schemes for asynchronous multi-user MIMO systems based on orthogonal space-time block codes (OSTBCs), where neither the transmitters nor the receiver has knowledge of the channel. First, we derive novel low complexity differential decoders by performing interference cancellation in time and employing different decoding methods. The decoding complexity of these schemes grows linearly with the number of users. We then present additional differential decoding schemes that perform significantly better than our low complexity decoders and outperform the existing synchronous differential schemes but require higher decoding complexity compared to our low complexity decoders. The proposed schemes work for any square OSTBC, any constant amplitude constellation, any number of users, and any number of receive antennas. Furthermore, we analyze the diversity of the proposed schemes and derive conditions under which our schemes provide full diversity. For the cases of two and four transmit antennas, we provide examples of PSK constellations to achieve full diversity. Simulation results show that our differential schemes provide good performance. To the best of our knowledge, the proposed differential detection schemes are the first differential schemes for asynchronous multi-user systems.

[1]  A. Calderbank,et al.  Further results on interference cancellation and space-time block codes , 2001, Conference Record of Thirty-Fifth Asilomar Conference on Signals, Systems and Computers (Cat.No.01CH37256).

[2]  Hamid Jafarkhani,et al.  Orthogonal Differential Modulation for MIMO Multiple Access Channels with Two Users , 2013, IEEE Transactions on Communications.

[3]  Manav R. Bhatnagar,et al.  Differential Coding for MAC Based Two-User MIMO Communication Systems , 2012, IEEE Transactions on Wireless Communications.

[4]  H. Bolcskei,et al.  Multiuser Space-Time/Frequency Code Design , 2006, 2006 IEEE International Symposium on Information Theory.

[5]  P. Stoica,et al.  Differential modulation using space-time block codes , 2002, IEEE Signal Processing Letters.

[6]  Sergio Verdú,et al.  The capacity region of the symbol-asynchronous Gaussian multiple-access channel , 1989, IEEE Trans. Inf. Theory.

[7]  A.R. Calderbank,et al.  Applications of space-time block codes and interference suppression for high capacity and high data rate wireless systems , 1998, Conference Record of Thirty-Second Asilomar Conference on Signals, Systems and Computers (Cat. No.98CH36284).

[8]  Siavash M. Alamouti,et al.  A simple transmit diversity technique for wireless communications , 1998, IEEE J. Sel. Areas Commun..

[9]  Branka Vucetic,et al.  Differential Space‐Time Block Codes , 2005 .

[10]  Giuseppe Durisi,et al.  Diversity versus channel knowledge at finite block-length , 2012, 2012 IEEE Information Theory Workshop.

[11]  Hamid Jafarkhani,et al.  Space-Time Coding - Theory and Practice , 2010 .

[12]  Guangxi Zhu,et al.  General differential space-time modulation , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[13]  Hamid Jafarkhani,et al.  Multiuser Interference Cancellation and Detection for Users with More Than Two Transmit Antennas , 2008, IEEE Transactions on Communications.

[14]  Hamid Jafarkhani,et al.  Multiple transmit antenna differential detection from generalized orthogonal designs , 2001, IEEE Trans. Inf. Theory.

[15]  Hamid Jafarkhani,et al.  Differential modulation based on quasi-orthogonal codes , 2005, IEEE Transactions on Wireless Communications.

[16]  Hamid Jafarkhani,et al.  A differential detection scheme for transmit diversity , 2000, IEEE Journal on Selected Areas in Communications.

[17]  A. Robert Calderbank,et al.  Space-Time block codes from orthogonal designs , 1999, IEEE Trans. Inf. Theory.

[18]  Meixia Tao,et al.  Differential space-time block codes , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[19]  Helmut Bölcskei,et al.  Multiuser Space-Time/Frequency Code Design , 2006, ISIT.

[20]  Matthias Brehler,et al.  Asymptotic error probability analysis of quadratic receivers in Rayleigh-fading channels with applications to a unified analysis of coherent and noncoherent space-Time receivers , 2001, IEEE Trans. Inf. Theory.

[21]  Hamid Jafarkhani,et al.  A quasi-orthogonal space-time block code , 2000, 2000 IEEE Wireless Communications and Networking Conference. Conference Record (Cat. No.00TH8540).