A unified capacity analysis for wireless systems with joint antenna and multiuser diversity in Nakagami fading channels

This paper presents a cross-layer analytical framework to jointly investigate antenna diversity and multiuser scheduling under the generalized Nakagami fading channels and derives a unified capacity formula for the multiuser scheduling system with different multiple-input multiple-output (MIMO) antenna schemes, including the selective combining (SC), maximum ratio combining (MRC) and space-time block codes (STBC). Our analytical results indicate that, in the presence of multiuser diversity, the multiple antennas with the SC method can be viewed as virtual users to amplify multiuser diversity order, while the MRC scheme can even yield greater capacity than the SC scheme due to the increased array gain. However, applying the STBC method on top of the multiuser scheduling system may lead to capacity loss due to the reduced amount of fading.