Improving the equal-spacing design in IEEE 802.11e HCCA wireless networks

In recent studies, an equal-spacing-based (equal-SP) design was developed to generalize and enhance the reference design in IEEE 802.11e standard. Different from the reference design in which all streams will be scheduled in a common minimum spacing, the equal-SP design may schedule different streams with different spacings and it might improve bandwidth utilization of the reference design, up to 22% or more. This paper proposes two new designs: the equal-SP-δ and equal-SP-l designs, to improve the equal-SP design further. Compared with the equal-SP design, the equal-SP-δ design introduces a δ-factor in the TXOP calculation and schedules different streams with longer spacings; numerical results show that it has a potential of improving bandwidth utilization, up to 8% or more. The equal-SP-l design can guarantee packet loss probability, which are not considered in the equal-SP design, with Gaussian traffic to approximate VBR traffic over different spacings; numerical results show it has a potential of improving bandwidth utilization, up to 54% or more, in contrast with the related design. Besides, the proposed two designs might reduce the additional computational complexity introduced in the equal-SP design.