On Locally Decodable Index Codes
Lakshmi Natarajan, Prasad Krishnan, V. Lalitha

TL;DR
This paper explores the trade-off between broadcast rate and locality in index coding, proposing new schemes that minimize the number of queried codeword symbols per message and characterizing this trade-off for specific graph structures.
Contribution
It introduces the concept of locality as a cost parameter in index coding and develops schemes that optimize the broadcast rate for given locality constraints.
Findings
Optimal locality is 1, achieved by fractional coloring schemes.
Proposed schemes cover side information graphs with acyclic and small minrank subgraphs.
Characterized the locality-broadcast rate trade-off for directed 3-cycle graphs.
Abstract
Index coding achieves bandwidth savings by jointly encoding the messages demanded by all the clients in a broadcast channel. The encoding is performed in such a way that each client can retrieve its demanded message from its side information and the broadcast codeword. In general, in order to decode its demanded message symbol, a receiver may have to observe the entire transmitted codeword. Querying or downloading the codeword symbols might involve costs to a client -- such as network utilization costs and storage requirements for the queried symbols to perform decoding. In traditional index coding solutions, this 'client aware' perspective is not considered during code design. As a result, for these codes, the number of codeword symbols queried by a client per decoded message symbol, which we refer to as 'locality', could be large. In this paper, considering locality as a cost…
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Taxonomy
TopicsCooperative Communication and Network Coding · Caching and Content Delivery
