In next generation wireless systems, such as Long Term Evo- lution (LTE), Radio Resource Management with Inter-cell Interference Co- ordination (ICIC) is a key issue to be addressed. Although centralized resource allocation (RA) and collaborative processing can optimally per- form ICIC, the overall required complexity suggests the consideration of distributed techniques. In this paper we investigate the behavior of dis- tributed RA strategies aimed at maximizing the weighted average sum-rate of a multi-cell clustered system in presence of power constraints by evaluat- ing throughput gap and fairness with respect to their respective centralized implementations. In the distributed RA strategies the inter-cell interfer- ence is partially coordinated through the use of power planning schemes (fractional frequency reuse - FFR - is the case considered here), leading to a reduction in both signaling and feedback requirements. Two different schedulers are analyzed and compared: the well-known proportional fair scheduler (PFS) and an Equal Rate Scheduler (ERS) aiming to guarantee equal average rate to each user. The results obtained show that the dis- tributed RA with aggressive frequency reuse is able to approach the perfor- mance of the centralized RA when the number of users is large. Moreover, with respect to full-reuse distributed RA, FFR is useful to improve fair- ness (or cell-edge user performance) at the expense of sum-rate when the scheduling weights are those of PFS, whereas it is able to improve through- put while preserving the fairness when the scheduling weights are those of ERS.
On the Performance of Distributed Power Allocation and Scheduling in Multi-Cell OFDMA Systems
CICALO', Sergio;TRALLI, Velio;
2011
Abstract
In next generation wireless systems, such as Long Term Evo- lution (LTE), Radio Resource Management with Inter-cell Interference Co- ordination (ICIC) is a key issue to be addressed. Although centralized resource allocation (RA) and collaborative processing can optimally per- form ICIC, the overall required complexity suggests the consideration of distributed techniques. In this paper we investigate the behavior of dis- tributed RA strategies aimed at maximizing the weighted average sum-rate of a multi-cell clustered system in presence of power constraints by evaluat- ing throughput gap and fairness with respect to their respective centralized implementations. In the distributed RA strategies the inter-cell interfer- ence is partially coordinated through the use of power planning schemes (fractional frequency reuse - FFR - is the case considered here), leading to a reduction in both signaling and feedback requirements. Two different schedulers are analyzed and compared: the well-known proportional fair scheduler (PFS) and an Equal Rate Scheduler (ERS) aiming to guarantee equal average rate to each user. The results obtained show that the dis- tributed RA with aggressive frequency reuse is able to approach the perfor- mance of the centralized RA when the number of users is large. Moreover, with respect to full-reuse distributed RA, FFR is useful to improve fair- ness (or cell-edge user performance) at the expense of sum-rate when the scheduling weights are those of PFS, whereas it is able to improve through- put while preserving the fairness when the scheduling weights are those of ERS.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
