IIIT Hyderabad Publications |
|||||||||
|
Locality in Index Coding for Large Min-RankAuthors: Lakshmi Prasad Natrajan, Hoang Dau,Prasad Krishnan,Lalitha Vadlamani Conference: The 2019 IEEE International Symposium on Information Theory ((ISIT) 2019) Location Paris, France Date: 2019-07-07 Report no: IIIT/TR/2019/59 AbstractAn index code is said to belocally decodableif eachreceiver can decode its demand using its side information andby querying only a subset of the transmitted codeword symbolsinstead of observing the entire codeword. Local decodability canbe a beneficial feature in some communication scenarios, suchas when the receivers can afford to listen to only a part of thetransmissions because of limited availability of power. Thelocalityof an index code is the ratio of the maximum number of codewordsymbols queried by a receiver to the message length. In this paperwe analyze the optimum locality of linear codes for the familyof index coding problems whose min-rank is one less than thenumber of receivers in the network. We first derive the optimaltrade-off between the index coding rate and locality with vectorlinear coding when the side information graph is a directed cycle.We then provide the optimal trade-off achieved by scalar linearcoding for a larger family of problems, viz. problems where themin-rank is only one less than the number of receivers. Whilethe arguments used for achievability are based on known codingtechniques, the converse arguments rely on new results on thestructure of locally decodable index codes. Full paper: pdf Centre for Communications |
||||||||
Copyright © 2009 - IIIT Hyderabad. All Rights Reserved. |