  A simple method is proposed for use in a scenario involving a single-antenna
source node communicating with a destination node that is equipped with two
antennas via multiple single-antenna relay nodes, where each relay is subject
to an individual power constraint. Furthermore, ultra-reliable and low-latency
communication are desired. The latter requirement translates to considering
only schemes that make use of local channel state information. Whereas for a
receiver equipped with a single antenna, distributed beamforming is a well
known and adequate solution, no straightforward extension is known. In this
paper, a scheme is proposed based on a space-time diversity transformation that
is applied as a front-end operation at the destination node. This results in an
effective unitary channel matrix replacing the scalar coefficient corresponding
to each user. Each relay node then inverts its associated channel matrix, which
is the generalization of undoing the channel phase in the classical case of
distributed beamforming to a single-antenna receiver, and then repeats the
message over the resulting "gain-only" channel. In comparison to a
single-antenna destination node, the method doubles the diversity order without
requiring any channel state information at the receiver while at the same time
retaining the array gain offered by the relays.
