In order to reduce the number of retransmissions and save power for the
source node, we propose a two-phase coded scheme to achieve reliable broadcast
from the source to a group of users with minimal source transmissions. In the
first phase, the information packets are encoded with batched sparse (BATS)
code, which are then broadcasted by the source node until the file can be
cooperatively decoded by the user group. In the second phase, each user
broadcasts the re-encoded packets to its peers based on their respective
received packets from the first phase, so that the file can be decoded by each
individual user. The performance of the proposed scheme is analyzed and the
rank distribution at the moment of decoding is derived, which is used as input
for designing the optimal BATS code. Simulation results show that the proposed
scheme can reduce the total number of retransmissions compared with the
traditional single-phase broadcast with optimal erasure codes. Furthermore,
since a large number of transmissions are shifted from the source node to the
users, power consumptions at the source node is significantly reduced.Comment: ICC 2015. arXiv admin note: substantial text overlap with
arXiv:1504.0446