English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

This paper considers the uplink of a cloud radio access network (C-RAN)comprised of several multi-antenna remote radio units (RUs) which compress thesignals that they receive from multiple mobile users (MUs) and forward them toa CU via wireless fronthaul links. To enable reliable high rate fronthaullinks, we employ a hybrid radio frequency (RF)/free space optical (FSO) systemfor fronthauling. To strike a balance between complexity and performance, weconsider three different quantization schemes at the RUs, namely per-antennavector quantization (AVQ), per-RU vector quantization (RVQ), and distributedsource coding (DSC), and two different receivers at the CU, namely the linearminimum mean square error receiver and the optimal successive interferencecancellation receiver. For this network architecture, we investigate the jointoptimization of the quantization noise covariance matrices at the RUs and theRF time allocation to the multiple-access and fronthaul links for rate regionmaximization. To this end, we formulate a unified weighted sum ratemaximization problem valid for each possible pair of the consideredquantization and detection schemes. To handle the non-convexity of the unifiedproblem, we transform it into a bi-convex problem which facilitates thederivation of an efficient suboptimal solution using alternating convexoptimization and golden section search. Our simulation results show that foreach pair of the considered quantization and detection schemes, C-RAN withhybrid RF/FSO fronthauling can achieve a considerable sum rate gain compared toconventional systems employing pure FSO fronthauling, especially underunfavorable atmospheric conditions. Moreover, employing a more sophisticatedquantization scheme can significantly improve the system performance underadverse atmospheric conditions.

C-RAN with Hybrid RF/FSO Fronthaul Links: Joint Optimization of RF Time Allocation and Fronthaul Compression