QoE Enhancement by Capacity Allocation and Piggyback Bandwidth Request in Audio-Video IP Transmission over the IEEE 802.16 BE Service

This paper studies QoE (Quality of Experience) enhancement of audio-video IP transmission over the uplink channel, i.e., from subscriber stations (SSs) to the base station (BS), in the IEEE 802.16 BE service. We assume two types of capacity allocation schemes for uplink and downlink burst durations: static and adaptive. Furthermore, we introduce a piggyback request mechanism for uplink bandwidth requests from SSs to the BS in addition to a random access-based request mechanism. We assess QoE of audio-video streams for four schemes obtained from the combination of the bandwidth request mechanisms and the capacity allocation schemes. We also employ two types of audio-video contents. From the assessment result, we notice that the piggyback request mechanism can enhance QoE of audio-video transmission. In addition, the adaptive allocation scheme is effective for QoE enhancement particularly under heavily loaded conditions because of its efficient usage of OFDM symbols. We also find that the effects of piggyback request mechanism and capacity allocation schemes on QoE change according to the content types.