WE2.R9.4

Quality Adaptation for Cache-aided Degraded Broadcast Channels

Eleftherios Lampiris, Giuseppe Caire, Technische Universität Berlin, Germany

Session:
Wireless 2

Track:
20: Wireless Communications and Networks

Location:
Lamda

Presentation Time:
Wed, 10 Jul, 12:30 - 12:50

Session Chair:
Tara Javidi, University of California San Diego
Abstract
This work focuses on the efficient delivery of content over the single antenna degraded broadcast channel with user caching through the adaptation of the content quality at the users. We design a delivery scheme which combines superposition coding, multicasting, and scalable video coding, while keeping the caching scheme oblivious to channel qualities. By lowering the quality at users who experience channel degradation we are able to satisfy user demands in a time efficient manner. In addition, superposition coding allows us to treat users with higher channel rates without subjecting them to a delay penalty due to their degraded counterparts’ channels. An interesting outcome of this work is that a modest reduction in the quality of the degraded users can counter the effects of a significant channel degradation. For example, in a 100-user channel with normalized cache size 1/10 at each user, if 10 users experience channel degradation of 60% compared to the rate of the non-degraded users, we show that our transmission strategy leads to a ∼ 85% quality at the degraded users and perfect quality at the non-degraded users.
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