Title :
Diversity combining and equalization of frequency-selective fading signals with unequal mean strengths
Author :
Lin, Sheng-Chou ; Prabhu, Vasant K.
Author_Institution :
Wireless Networks, Northern Telecom Inc., Richardson, TX, USA
Abstract :
This paper investigates the performance of unbalanced diversity structures combined with equalization techniques operating in a mobile radio environment with frequency-selective fading which is characterized by two Rayleigh-fading beams. The received signals are statistically independent, but the mean signal-to-noise ratios on various diversity branches are unequal. Quadrature amplitude modulation (QAM) and two optimum diversity structures, combining-diversity and selection-diversity, are considered in our analysis, Both linear and decision-feedback equalization with infinite taps and finite taps are used in the optimum diversity structures. Even though a degree of degradation that is proportional to the differences in mean power may result, unbalanced-diversity systems still can operate effectively in a frequency-selective fading channel. However, the diversity gain is almost lost when the unequal mean power is greater than 15 dB for 2-path diversity systems
Keywords :
Rayleigh channels; decision feedback equalisers; diversity reception; land mobile radio; quadrature amplitude modulation; QAM; Rayleigh-fading beams; combining-diversity; decision-feedback equalization; degradation; diversity branches; diversity combining; equalization; finite tap; frequency-selective fading; frequency-selective fading channel; frequency-selective fading signals; infinite taps; linear equalization; mean signal-to-noise ratios; mobile radio environment; optimum diversity structure; quadrature amplitude modulation; received signals; selection-diversity; unbalanced diversity structures; unbalanced-diversity systems; unequal mean power; unequal mean strengths; Decision feedback equalizers; Degradation; Diversity methods; Diversity reception; Frequency diversity; Frequency-selective fading channels; Land mobile radio; Quadrature amplitude modulation; Rayleigh channels; Signal to noise ratio;
Conference_Titel :
Vehicular Technology Conference, 1998. VTC 98. 48th IEEE
Conference_Location :
Ottawa, Ont.
Print_ISBN :
0-7803-4320-4
DOI :
10.1109/VETEC.1998.683682