A novel design of ternary signal sets is proposed for estimation of multiuser fibre-wireless (Fi-Wi) uplink channels. The design overcomes the current limitation in the maximum number of users that the system can accommodate by separating the signals in a set into subsets. The signals are uncorrelated between subsets, but correlated within subsets, thus forming a semi-correlated ternary pseudo-random signal (SC-TPRS) set. An iterative channel estimator based on the SC-TPRS scheme is then proposed for joint estimation of the Fi-Wi uplink channel. The computational complexity associated with the existing and the proposed estimators is derived and it is shown that the latter incurs substantially lower computational cost than the former. Numerical results show that despite using signals which are a few hundred times shorter, the proposed scheme can improve estimation accuracy dramatically over the existing scheme at low signal-to-noise ratios. The proposed scheme has a further advantage of allowing the designer to optimise the Fi-Wi system under the constraint of maximum permissible level of multiple access interference, since the amount of interference can be tuned by adjusting the number and size of the ternary signal subsets.

References

1. 1)
  - 18. Ng, Y.H., Chuah, T.C., Tan, A.H.: ‘Uplink channel estimation for multiuser fiber-wireless systems using ternary signals’, IEEE Communications Letters, 2012, 16, (10), pp. 1672–1675 (doi: 10.1109/LCOMM.2012.090312.120459).
2. 2)
  - 22. Evans, C., Rees, D.: ‘Nonlinear distortions and multisine signals – Part I: Measuring the best linear approximation’, IEEE Trans. Instrum. Meas., 2000, 49, (3), pp. 602–609 (doi: 10.1109/19.850402).
3. 3)
  - 6. Hekkala, A., Hiivala, M., Lasanen, M., et al: ‘Predistortion of radio over fiber links: algorithms, implementation, and measurements’, IEEE Trans. Circuits Syst. I: Regul. Pap., 2012, 59, (3), pp. 664–672 (doi: 10.1109/TCSI.2011.2167267).
4. 4)
  - 22. Tan, A.H., Godfrey, K.R., Barker, H.A.: ‘Design of ternary signals for MIMO identification in the presence of noise and nonlinear distortion’, IEEE Trans. Control Syst. Technol., 2009, 17, (4), pp. 926–933 (doi: 10.1109/TCST.2009.2012424).
5. 5)
  - 21. Tan, A.H.: ‘Design of truncated maximum length ternary signals where their squared versions have uniform even harmonics’, IEEE Trans. Automat. Contr., 2007, 52, (5), pp. 957–961 (doi: 10.1109/TAC.2007.895852).
6. 6)
  - 3. Baghersalimi, G., O'Farrell, T.: ‘Pilot-aided estimation and equalisation of a radio-over-fibre system in wideband code division multiple access’, IET Commun., 2013, 7, (10), pp. 999–1007 (doi: 10.1049/iet-com.2012.0660).
7. 7)
  - 20. Barker, H.A.: ‘Design of multi-level pseudo-random signals for system identification’, in Godfrey, K. (Ed.): ‘Perturbation signals for system identification’ (Prentice-Hall, Hemel Hempstead, 1993, 1st edn.), pp. 321–343.
8. 8)
  - 7. Fock, L.S., Tucker, R.S.: ‘Simultaneous reduction of intensity noise and distortion in semiconductor laser by feed forward compensation’, Electron. Lett., 1991, 27, (14), pp. 1297–1298 (doi: 10.1049/el:19910811).
9. 9)
  - 15. Pinter, S.Z., Fernando, X.N.: ‘Estimation and equalization of fiber-wireless uplink for multiuser CDMA 4G networks’, IEEE Trans. Commun., 2010, 58, (6), pp. 1803–1813 (doi: 10.1109/TCOMM.2010.06.090114).
10. 10)
  - 1. Pahlavan, K., Krishnamurthy, P.: ‘Principles of wireless access and localization’ (John Wiley and Sons, 2013, 1st edn.).
11. 11)
  - 1. Fernando, X.N., Sesay, A.B.: ‘Adaptive asymmetric linearization of radio over fiber links for wireless access’, IEEE Trans. Veh. Technol., 2002, 51, (6), pp. 1576–1586 (doi: 10.1109/TVT.2002.804841).
12. 12)
  - 13. Fernando, X.N., Sesay, A.B.: ‘A Hammerstein-type equalizer for concatenated fiber-wireless uplink’, IEEE Trans. Veh. Technol., 2005, 54, (6), pp. 1980–1991 (doi: 10.1109/TVT.2005.858170).
13. 13)
  - 10. Fernando, X.N.: ‘Radio over fiber for wireless communications: From fundamentals to advanced topics’ (John Wiley and Sons, West Sussex, 2014, 1st edn.).
14. 14)
  - 6. Fernandes, C.A.R., Favier, G., Mota, J.C.M.: ‘PARAFAC-based channel estimation and data recovery in nonlinear MIMO spread spectrum communication systems’, Signal Process., 2011, 91, (2), pp. 311–322 (doi: 10.1016/j.sigpro.2010.07.010).
15. 15)
  - 17. Pintelon, R., Schoukens, J.: ‘System identification: A frequency domain approach’ (John Wiley & Sons, Hoboken, New Jersey, 2012, 2nd edn.).
16. 16)
  - 23. Kulesza, Z.: ‘Dynamic behavior of cracked rotor subjected to multisine excitation’, J. Sound Vib., 2014, 333, (5), pp. 1369–1378 (doi: 10.1016/j.jsv.2013.10.031).
17. 17)
  - 4. Guillory, J.: ‘Radio over fiber (RoF) for the future home area networks’. Ph.D. thesis, University of Paris-Est, 2012.
18. 18)
  - 16. Ng, Y.H., Tan, A.H., Chuah, T.C.: ‘Channel identification of concatenated fiber-wireless uplink using ternary signals’, IEEE Trans. Veh. Technol., 2011, 60, (7), pp. 3207–3217 (doi: 10.1109/TVT.2011.2162012).
19. 19)
  - 8. Fernando, X.N., Sesay, A.B.: ‘Look-up table based adaptive predistortion for dynamic range enhancement in a radio over fiber link’. IEEE Pacific Rim Conf. on Communications, Computers and Signal Processing (PACRIM'99), Victoria, BC, Canada, August 1999, pp. 26–29.
20. 20)
  - 24. Tan, A.H.: ‘Direct synthesis of pseudo-random ternary perturbation signals with harmonic multiples of two and three suppressed’, Automatica, 2013, 49, (10), pp. 2975–2981 (doi: 10.1016/j.automatica.2013.07.009).
21. 21)
  - 9. Way, W.I.: ‘Optical fiber based microcellular systems: An overview’, IEICE Trans. Commun., 1993, E76-B, (9), pp. 1091–1102.
22. 22)
  - 2. Theodoridis, S., Kopsinis, Y., Slavakis, K.: ‘Sparsity-aware learning and compressed sensing: An overview’, in Diniz, P.S.R., Suykens, J.A.K., Chellappa, R., Theodoridis, S. (Eds.): ‘Academic Press library in signal processing: Signal processing theory and machine learning’ (Elsevier, UK, 2014, 1st edn.), pp. 1271–1378.
23. 23)
  - 12. Zhang, X., Zhu, R., Shen, D., et al: ‘Linearization technologies for broadband radio-over-fiber transmission systems’, Photonics, 2014, 1, (4), pp. 455–472 (doi: 10.3390/photonics1040455).
24. 24)
  - 14. Fernando, X.N., Sesay, A.B.: ‘Fibre-wireless channel estimation using correlation properties of PN sequences’, Can. J. Electr. Comput. Eng., 2001, 26, (2), pp. 43–47.

Iterative channel estimation for multiuser fibre-wireless uplink exploiting semi-correlated ternary signals

References

Related content