  Unsourced random access (URA) has emerged as a pragmatic framework for
next-generation distributed sensor networks. Within URA, concatenated coding
structures are often employed to ensure that the central base station can
accurately recover the set of sent codewords during a given transmission
period. Many URA algorithms employ independent inner and outer decoders, which
can help reduce computational complexity at the expense of a decay in
performance. In this article, an enhanced decoding algorithm is presented for a
concatenated coding structure consisting of a wide range of inner codes and an
outer tree-based code. It is shown that this algorithmic enhancement has the
potential to simultaneously improve error performance and decrease the
computational complexity of the decoder. This enhanced decoding algorithm is
applied to two existing URA algorithms and the performance benefits of the
algorithm are characterized. Findings are supported by numerical simulations.
