Multiuser Diversity based Adaptive Scheduling Scheme for OFDMA systems
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초록
For the case of a multiuser OFDMA system, users are opportunistically selected based on their individual Channel Quality Information (CQI) which have been reported to the Base Station (BS) in the form of uplink feedback. The feedback can either be detailed resulting in large feedback overhead or be partial resulting in small overhead but with insufficient CQI (which prohibit in accurately exploiting MUD). For either way, system throughput remains non optimal since there exists a trade-off in the amount and quality of feedback. Hence to address this issue, partial feedback with best-M scheduling has been previously proposed, where only CQI of M subchannels are reported to BS instead of reporting about all subchannels which thus reduces the uplink overhead. In this paper, to further increase the system throughput, we propose an adaptive best-M feedback scheduling where M is adaptively calculated based on the number of active users in the system. Through computer simulations, we show that the proposed scheme offers higher or equal downlink throughput with remarkably reduced uplink overhead, and increases the system capacity to support larger number of users simultaneously, in comparison to the best-M scheduling scheme. In addition, under the given constraint of the total feedback overhead, we investigated the critical operating points to fit optimal throughput in the system.
Abstract
For the case of a multiuser OFDMA system, users are opportunistically selected based on their individual Channel Quality Information (CQI) which have been reported to the Base Station (BS) in the form of uplink feedback. The feedback can either be detailed resulting in large feedback overhead or be partial resulting in small overhead but with insufficient CQI (which prohibit in accurately exploiting MUD). For either way, system throughput remains non optimal since there exists a trade-off in the amount and quality of feedback. Hence to address this issue, partial feedback with best-M scheduling has been previously proposed, where only CQI of M subchannels are reported to BS instead of reporting about all subchannels which thus reduces the uplink overhead. In this paper, to further increase the system throughput, we propose an adaptive best-M feedback scheduling where M is adaptively calculated based on the number of active users in the system. Through computer simulations, we show that the proposed scheme offers higher or equal downlink throughput with remarkably reduced uplink overhead, and increases the system capacity to support larger number of users simultaneously, in comparison to the best-M scheduling scheme. In addition, under the given constraint of the total feedback overhead, we investigated the critical operating points to fit optimal throughput in the system.
참고문헌 (13)
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