End-to-End Rate Enhancement in C-RAN Using Multi-Pair Two-Way Computation

TL;DR

This paper introduces a joint uplink and downlink transmission scheme in C-RAN that uses lattice-based computation to significantly improve end-to-end user data rates by decoding integer linear combinations of user codewords.

Contribution

The paper proposes a novel multi-pair two-way transmission scheme in C-RAN utilizing lattice-based computation for joint uplink and downlink optimization, enhancing data rates.

Findings

Achieves higher end-to-end data rates compared to existing schemes.

Utilizes lattice-based computation for efficient message decoding.

Demonstrates significant rate improvements through numerical evaluation.

Abstract

Cloud radio-access networks (C-RAN) have been proposed as an enabling technology for keeping up with the requirements of next-generation wireless networks. Most existing works on C-RAN consider the uplink or the downlink separately. However, designing the uplink and the downlink jointly may bring additional advantage, especially if message source-destination information is taken into account. In this paper, this idea is demonstrated by considering pairwise message exchange between users in a C-RAN. A multi-pair two-way transmission scheme is proposed which targets maximizing the end-to-end user data rates. In the proposed scheme, a lattice-based computation strategy is used, where the baseband processing unit (BBU) pool decodes integer linear combinations of paired users' codewords instead of decoding linear combinations of individual codewords. The BBU pool then compresses the computed signals and forwards them to the remote radio heads (RRHs), which decompress the signals and send them to the users. Finally, each user decodes its desired message using its own message as side information. The achievable rate of this scheme is derived, optimized, and evaluated numerically. Results reveal that significant end-to-end rate improvement can be achieved using the proposed scheme compared to existing schemes.