Fronthaul data compression for Uplink CoMP in cloud radio access network (C‐RAN)

Abstract

The design of efficient wireless fronthaul connections for future heterogeneous networks incorporating emerging paradigms such as cloud radio access network (C-RAN) has become a challenging task that requires the most effective utilization of fronthaul network resources. In this paper, we propose to use distributed compression to reduce the fronthaul traffic in uplink Coordinated Multi-Point (CoMP) for C-RAN. Unlike the conventional approach where each coordinating point quantizes and forwards its own observation to the processing centre, these observations are compressed before forwarding. At the processing centre, the decompression of the observations and the decoding of the user message are conducted in a successive manner.The essence of this approach is the optimization of the distributed compression using an iterative algorithm to achieve maximal user rate with a given fronthaul rate. In other words, for a target user rate the generated fronthaul traffic is minimized. Moreover, joint decompression and decoding is studied and an iterative optimization algorithm is devised accordingly. Finally, the analysis is extended to multi-user case and our results reveal that, in both dense and ultra-dense urban deployment scenarios, the usage of distributed compression can efficiently reduce the required fronthaul rate and a further reduction is obtained with joint operation. Index TermsHeterogeneous network (HetNet), fronthaul, uplink Coordinated Multi-Point (CoMP), cloud radio access network (C-RAN), distributed compression. I INTRODUCTIONThe astronomical growth in mobile data traffic volume is making it increasingly difficult for operators to meet the traffic demands with the available resources and network architecture. This remarkable growing momentum of improving the quality of experience of the users will most likely continue due to the emerging needs of connecting people, machines, and applications through mobile infrastructure. Extrapolation of current growth trend predicts that the future networks are required to be prepared to support up to a thousand fold increase in total mobile broadband traffic by 2020 [1]. In light of this trend, heterogeneous network (HetNet), where small cells (SCs) are deployed to provide improved coverage and capacity to highly concentrated users, is envisaged as one of the key solutions to economic and sustainable future networks [2]- [4]. However, each added small cell has a profound effect on overall network performance, both with the increased capacity it brings as well as the large amount of co-channel interference it generates when sharing the same frequency [5]. One of the ways to improve the spectral efficiency of the system and mitigate the adverse effect of the huge interference is the use of advanced Coordinated Multi-Point However, in these works the coordinating SCs are assumed to simply quantize their own received signals before forwarding them to the processing centre via the fronthaul links.Considering the fact that the observations of all coordinating cells...

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