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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this article, the new term, namely beam-space multiplexing, is proposedfor the former multi-layer beamforming for 4G TD-LTE in 3GPP releases. Weprovide a systematic overview of beam-space multiplexing from engineering andtheoretical perspectives. Firstly, we clarify the fundamental theory ofbeam-space multiplexing. Specifically, we provide a comprehensive comparisonwith the antenna-space multiplexing in terms of theoretical analysis, channelstate information acquisition, and engineering implementation constraints.Then, we summarize the key technologies and 3GPP standardization of beam-spacemultiplexing in 4G TD-LTE and 5G new radio (NR) in terms of multi-layerbeamforming and massive beamforming, respectively. We also provide system-levelperformance evaluation of beam-space multiplexing schemes and field resultsfrom current commercial TD-LTE networks and field trial of 5G. The practicaldeployments of 4G TD-LTE and 5G cellular networks demonstrate the superiorityof beam-space multiplexing within the limitations of implementation complexityand practical deployment scenarios. Finally, the future trends of beam-spacemultiplexing in 6G and beyond are discussed, including massive beamforming forextremely large-scale MIMO (XL-MIMO), low earth orbit (LEO) satellitescommunication, data-driven intelligent massive beamforming, and multi-targetspatial signal processing, i.e., joint communication and sensing, positioning,etc.

Beam-space Multiplexing: Practice, Theory, and Trends-From 4G TD-LTE, 5G, to 6G and Beyond