Due to their superior performance and moderate computational complexity, quasi-orthogonal space–frequency block codes (QOSFBCs) and quasi-orthogonal space–time–frequency block codes (QOSTFBCs) are among prime candidates for implementation in multiple-input multiple-output communications systems. Originally, these codes were introduced for two transmit antennas and it is proved that they are full-diversity within channels with equal-power profile and integer delays. In this study, first, the authors generalise the construction of QOSFBCs and QOSTFBCs for arbitrary number of transmit antennas. Then, they provide the theoretical proof that these codes are full-diversity for any arbitrary number of transmit antennas and any arbitrary delay and power profiles. Furthermore, they prove that the coding advantage of these codes is decomposed into two distinct parts, one of which represents the effect of the channel and the other represents the effect of the precoder. By optimising these two parts, they propose a modified version of QOSFBCs and QOSTFBCs which outperforms the latest space–frequency block codes and space–time–frequency block codes in the literature according to the analytical results and support of simulation results. Finally, they propose a new suboptimum linear decoder for the QOSFBCs and the QOSTFBCs which could achieve almost the same performance as the maximum-likelihood decoder for large number of subcarriers.

References

1. 1)
  - 9. Bolcskei, H., Paulraj, A.J.: ‘Space–frequency coded broadband OFDM systems’. Proc. 2000 IEEE Wireless Communications and Networking Conf., Chicago, IL, September 2000, vol. 1, pp. 1–6.
2. 2)
  - 10. Liu, Z., Xin, Y., Giannakis, G.: ‘Linear constellation precoding for OFDM with maximum multipath diversity and coding gains’, IEEE Trans. Commun., 2003, 51, (3), pp. 416–427.
3. 3)
  - 6. Mohammadian, Z., Shahabinejad, M., Talebi, S.: ‘New full-diversity space–frequency block codes based on the OSTBCs’, IEEE Commun. Lett., 2012, 16, (10), pp. 1620–1623.
4. 4)
  - 23. Jafarkhani, H.: ‘Space–time coding theory and practice’ (Cambridge University Press, Cambridge, UK, 2005).
5. 5)
  - 12. Zhang, W., Xia, X.-G., Ching, P.C.: ‘High-rate full-diversity space time–frequency codes for broadband MIMO block-fading channels’, IEEE Trans. Commun., 2007, 55, pp. 25–34.
6. 6)
  - 5. Shao, L., Roy, S.: ‘Rate-one space–frequency block codes with maximum diversity for MIMO-OFDM’, IEEE Trans. Wirel. Commun., 2005, 4, (4), pp. 1674–1687.
7. 7)
  - 15. Shahabinejad, M., Talebi, S.: ‘Full-diversity space–time–frequency coding with very low complexity for the ML decoder’, IEEE Commun. Lett., 2012, 16, (5), pp. 658–661.
8. 8)
  - 19. Yoo, J., Choe, S.: ‘Performance of space–time–frequency coding over indoor power line channels’, IEEE Trans. Commun., 2014, 62, (9), pp. 3326–3335.
9. 9)
  - 2. Su, W., Safar, Z., Olfat, M., et al: ‘Obtaining full-diversity space–frequency codes from space–time codes via mapping’, IEEE Trans. Signal Process., 2003, 51, pp. 2905–2916.
10. 10)
  - 11. Liu, Z., Xin, Y., Giannakis, G.B.: ‘Space–time–frequency coded OFDM over frequency-selective fading channels’, IEEE Trans. Signal Process., 2002, 10, pp. 2465–2476.
11. 11)
  - 18. Tran, L., Mertins, A., Wysocki, T.: ‘Unitary differential space–time–frequency codes for mb-ofdm uwb wireless communications’, IEEE Trans. Wirel. Commun., 2013, 12, (2), pp. 862–876.
12. 12)
  - 22. Horn, R.A., Johnson, C.R.: ‘Matrix analysis’ (Cambridge University Press, Cambridge, UK, 1985).
13. 13)
  - 16. Yang, W., Cai, Y., Zheng, B.: ‘Distributed space–time–frequency coding for broadband wireless relay networks’, IEEE Trans. Veh. Technol., 2012, 61, (1), pp. 15–21.
14. 14)
  - 13. Zhang, W., Xia, X.G., Ching, P.C.: ‘Full-diversity and fast ML decoding properties of general orthogonal space–time block codes for MIMO-OFDM systems’, IEEE Trans. Wirel. Commun., 2007, 6, pp. 1647–1653.
15. 15)
  - 7. Shahabinejad, M., Hosseini, F.G., Talebi, S.: ‘Space–frequency codes based on the space–time codes with very low complexity for the decoder’, IEEE Trans. Veh. Technol., 2013, 62, (9), pp. 4678–4684.
16. 16)
  - 20. Fazel, F., Jafarkhani, H.: ‘Quasi-orthogonal space–frequency and space–time–frequency block codes for MIMO OFDM channels’, IEEE Trans. Wirel. Commun., 2008, 7, pp. 184–192.
17. 17)
  - 1. Su, W., Safar, Z., Liu, K.J.R.: ‘Full-rate full-diversity space–frequency codes with optimum coding advantage’, IEEE Trans. Inf. Theory, 2005, 51, (1), pp. 229–249.
18. 18)
  - 14. Bhavani Shankar, M. R., Hari, K.V.S.: ‘Systematic construction of linear transform based full-diversity, rate-one space–time frequency codes’, IEEE Trans. Signal Process., 2009, 57, (6), pp. 2285–2298.
19. 19)
  - 3. Fazel, F., Jafarkhani, H.: ‘Quasi-orthogonal space–frequency block codes for MIMO OFDM channels’. Proc. IEEE Int. Conf. on Communications, June 2006.
20. 20)
  - 17. Vien, Q.-T., Stewart, B., Nguyen, H., et al: ‘Distributed space–time–frequency block code for cognitive wireless relay networks’, IET Commun., 2014, 8, (5), pp. 754–766.
21. 21)
  - 21. Shahabinejad, M., Morsali, A., Talebi, S., et al: ‘On the coding advantages of the QOSFBCs’, IET Commun.., 2014, 8, (4), pp. 525–529.
22. 22)
  - 8. Su, W., Safar, Z., Liu, K.J.R.: ‘Towards maximum achievable diversity in space, time and frequency: performance analysis and code design’, IEEE Trans. Wirel. Commun., 2005, 4, (4), pp. 1847–1857.
23. 23)
  - 4. Kiran, T., Rajan, B.S.: ‘A systematic design of high-rate full-diversity space frequency codes for MIMO-OFDM systems’. Proc. IEEE Int. Symp. Information Theory, September 2005.
24. 24)
  - 24. Alamouti, S.M.: ‘A simple transmit diversity technique for wireless communications’, IEEE J. Sel. Areas Commun., 1998, 16, (8), pp. 1451–1458.

Quasi-orthogonal space–frequency and space–time–frequency block codes with modified performance and simplified decoder

References

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