  This paper investigates the performance of streaming codes in low-latency
applications over a multi-link three-node relayed network. The source wishes to
transmit a sequence of messages to the destination through a relay. Each
message must be reconstructed after a fixed decoding delay. The special case
with one link connecting each node has been studied by Fong et. al [1], and a
multi-hop multi-link setting has been studied by Domanovitz et. al [2]. The
topology with three nodes and multiple links is studied in this paper. Each
link is subject to a different number of erasures due to different channel
conditions. An information-theoretic upper bound is derived, and an achievable
scheme is presented. The proposed scheme judiciously allocates rates for each
link based on the concept of delay spectrum. The achievable scheme is compared
to two baseline schemes and the scheme proposed in [2]. Experimental results
show that this scheme achieves higher rates than the other schemes, and can
achieve the upper bound even in non-trivial scenarios. The scheme is further
extended to handle different propagation delays in each link, something not
previously considered in the literature. Simulations over statistical channels
show that the proposed scheme can outperform the simpler baseline under
practical models.
