Exact performance analysis of hybrid adaptive modulation schemes in multi-channel system

In this paper, we analyze the performance of a multi-channel system with the conventional adaptive modulation (AM) and two hybrid schemes, the adaptive modulation with diversity combining (AMDC) and the adaptive modulation with power loading (AMPL), respectively. In order to achieve higher spectral efficiency and more efficient usage of channel resources under the total transmit power constraint and the required bit error rate (BER), the AMDC jointly uses discrete-rate adaptation and diversity combining scheme, and the AMPL jointly uses discrete-rate adaptation and sub-optimal discrete-power loading. We derive exact closed-form expressions of the performance of a multi-channel system with the conventional adaptive modulation (AM) and these hybrid schemes, in terms of the spectral efficiency, the average BER and the outage probability. We also analyze the impact of imperfect channel estimation on the error performance and validate our analytical results by simulations. Numerical results show that both the AMDC and the AMPL offer higher spectral efficiency than the conventional AM, assuming the perfect channel estimation. However, AMDC offers better performance and reliability than AMPL, under imperfect channel estimation with complex Gaussian error.

[1]  Milton Abramowitz,et al.  Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables , 1964 .

[2]  A. Goldsmith,et al.  Effect of channel estimation error on M-QAM BER performance in Rayleigh fading , 1999, 1999 IEEE 49th Vehicular Technology Conference (Cat. No.99CH36363).

[3]  Mohamed-Slim Alouini,et al.  Digital Communication over Fading Channels: Simon/Digital Communications 2e , 2004 .

[4]  Mohamed-Slim Alouini,et al.  Adaptive Modulation over Nakagami Fading Channels , 2000, Wirel. Pers. Commun..

[5]  José F. Paris,et al.  Impact of channel estimation error on adaptive modulation performance in flat fading , 2004, IEEE Transactions on Communications.

[6]  Andrea J. Goldsmith,et al.  Degrees of freedom in adaptive modulation: a unified view , 2001, IEEE Trans. Commun..

[7]  Andrea J. Goldsmith,et al.  Adaptive coded modulation for fading channels , 1998, IEEE Trans. Commun..

[8]  D. Owen.  Handbook of Mathematical Functions with Formulas , 1965 .

[9]  M. Gans.  The Effect of Gaussian Error in Maximal Ratio Combiners , 1971 .

[10]  Mohamed-Slim Alouini,et al.  Performance Analysis of Joint Adaptive Modulation and Diversity Combining Over Fading Channels , 2006, IEEE Transactions on Communications.

[11]  Joseph Lipka,et al.  A Table of Integrals , 2010 .

[12]  Dongweon Yoon,et al.  On the general BER expression of one- and two-dimensional amplitude modulations , 2002, IEEE Trans. Commun..

[13]  Paul Fortier,et al.  Maximal-ratio combining architectures and performance with channel estimation based on a training sequence , 2004, IEEE Transactions on Wireless Communications.

[14]  B. Holter,et al.  On the amount of fading in MIMO diversity systems , 2005, IEEE Transactions on Wireless Communications.

[15]  Mohamed-Slim Alouini,et al.  Spectral Efficiency Enhancement in Multi-Channel Systems Using Redundant Transmission and Diversity Reception , 2008, IEEE Transactions on Wireless Communications.