  A novel coding design is proposed to enhance information retrieval in a
wireless network of users with partial access to the data, in the sense of
observation, measurement, computation, or storage. Information exchange in the
network is assisted by a multi-antenna base station (BS), with no direct access
to the data. Accordingly, the missing parts of data are exchanged among users
through an uplink (UL) step followed by a downlink (DL) step. In this paper,
new coding strategies, inspired by coded caching (CC) techniques, are devised
to enhance both UL and DL steps. In the UL step, users transmit encoded and
properly combined parts of their accessible data to the BS. Then, during the DL
step, the BS carries out the required processing on its received signals and
forwards a proper combination of the resulting signal terms back to the users,
enabling each user to retrieve the desired information. Using the devised coded
data retrieval strategy, the data exchange in both UL and DL steps requires the
same communication delay, measured by normalized delivery time (NDT).
Furthermore, the NDT of the UL/DL step is shown to coincide with the optimal
NDT of the original DL multi-input single-output CC scheme, in which the BS is
connected to a centralized data library.
