In this paper, we study the capacity region of the general distributed index coding. In contrast to the traditional centralized index coding where a single server contains all n messages requested by the receivers, in the distributed index coding there are 2 n − 1 servers, each containing a unique non-empty subset J of the messages and each is connected to all receivers via a noiseless independent broadcast link with an arbitrary capacity CJ ≥ 0. First, we generalize the existing outer bound on the capacity region of the centralized problem to the distributed case. Next, building upon the existing centralized composite coding scheme, we propose three distributed composite coding schemes and derive the corresponding inner bounds on the capacity region. We present a number of interesting numerical examples, which highlight the subtleties and challenges of dealing with the distributed index coding, even for very small problem sizes of n = 3 and n = 4.
Sadeghi et al. REF considered a general multi-sender unicast setting, where there are 2 N − 1 senders each containing a different subset of the N messages in the system and each connected to all N receivers by noiseless broadcast links of arbitrary finite capacity.
Distributed index coding
2016 IEEE Information Theory Workshop (ITW)
2016 IEEE Information Theory Workshop (ITW)
Computer Science Mathematics