Multistage Relaying Using Interference Networks

TL;DR

This paper introduces three multihopping decode-and-forward protocols for half-duplex relay networks, demonstrating they can approach capacity under certain conditions by employing interference network coding without relay cooperation.

Contribution

The work proposes novel MDF protocols for multistage half-duplex relay networks that do not require relay cooperation, advancing practical relay network design.

Findings

Protocols approach capacity in certain channel gain ranges

Interference network coding enhances relay network performance

Multistage relaying can rival full-duplex systems with proper coding

Abstract

Wireless networks with multiple nodes that relay information from a source to a destination are expected to be deployed in many applications. Therefore, understanding their design and performance under practical constraints is important. In this work, we propose and study three multihopping decode and forward (MDF) protocols for multistage half-duplex relay networks with no direct link between the source and destination nodes. In all three protocols, we assume no cooperation across relay nodes for encoding and decoding. Numerical evaluation in illustrative example networks and comparison with cheap relay cut-set bounds for half-duplex networks show that the proposed MDF protocols approach capacity in some ranges of channel gains. The main idea in the design of the protocols is the use of coding in interference networks that are created in different states or modes of a half-duplex network. Our results suggest that multistage half-duplex relaying with practical constraints on cooperation is comparable to point-to-point links and full-duplex relay networks, if there are multiple non-overlapping paths from source to destination and if suitable coding is employed in interference network states.