Laboratory Experiments of TDD/SDMA OFDM Wireless Backhaul in a Downlink for Hierarchical Broadband Wireless Access Systems

In next generation Broadband Wireless Access (BWA) systems, cell shrinkage and blind zones might occur at cell edges due to constraints on transmission power and the increase in propagation loss with broadband and higher frequency bands, respectively. Thus, hierarchical BWA systems consisting of micro and macro Base transceiver Stations (BSs) installed around the macro BS are considered as one of the candidate radio access network architectures for the next generation BWA systems. In the hierarchical BWA system, a wireless backhaul between micro and macro BSs needs high capacity transmission to serve all Subscriber Stations (SSs) in each micro BSs.