An OFDM WLAN Multicast Hybrid Erasure Correction Prototype with Feedback Aggregation and Rate Adaptation

Inhalt:
Aggregation of multicast feedback in time is evaluated herein with respect to physical layer rate adaptation in OFDM based WLANs. An opportunistic scheduler with perfect channel knowledge is used as an upper limit for multicast throughput. We find that feedback aggregation multicast performs close to this limit. In realistic fading scenarios, delay constrained audio-visual streaming performance of a hybrid overlay FEC prototype implementation – including feedback aggregation and rate adaptation – is evaluated by simulation. In this context, a popular unicast rate adaptation mechanism is extended to multicast streaming, and its residual error performance is improved significantly by simple means. Index Terms — OFDM; 802.11; MBMS; wireless multicast; feedback aggregation; rate adaptation