A Novel Scheduler Design for Wireless Video over 802.11aa Networks Using Priority Weighting and Dropping
Wen-Ping Lai, En-Cheng Liou · 2013
In the newly released 802.11aa-2012 protocol, intra access category prioritization (IACP) and drop eligibility indicator (DEI) enable stream classification service (SCS) with graceful degradation for robust audio and video streaming. IACP introduces the need for scheduling between the primary and alternative AC queues (AC_VI and AAC_VI) for differentiating realtime and non-real-time video streams. This paper proposes a novel cross-layer design for the scheduler between AC_VI and AAC_VI, which combines a real-time video importance scheme in the Application layer and a priority weighting and dropping algorithm (PWD) in the MAC layer, where priority weighting is applied only to AC_VI and priority dropping to both AC_VI and AAC_VI. The results show that the proposed design outperforms the conventional ones, including IACP-RR, ICAP-WRR, and SCS-WRR, with substantial performance gains for both real-time and non-real-time video streams via AC_VI and AAC_VI. Such a win-win game, not possibly achieved by the conventional designs, shows the true power of PWD.