TH1.R9.4

Coded Multi-User Information Retrieval with a Multi-Antenna Helper Node

Milad Abolpour, MohammadJavad Salehi, University of Oulu, Finland; Soheil Mohajer, University of Minnesota, United States; Seyed Pooya Shariatpanahi, University of Tehran, Iran; Antti Tölli, University of Oulu, Finland

Session:
Coding Over Networks

Track:
21: Other topics

Location:
Lamda

Presentation Time:
Thu, 11 Jul, 10:45 - 11:05

Session Chair:
Parastoo Sadeghi, The University of New South Wales
Abstract
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.
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