Using LDM to achieve seamless local service coverage in SFN environment

Abstract

This paper studies layered division multiplexing (LDM) for local cover age/services, such as location targeted advertisement or local content insertion. The LDM upper layer can be used to deliver time-division multiplexed (TDM-ed) mobile-HD and 4k-UHD services. The LDM lower layer with a negative SNR threshold can reliably provide seamless local coverage/service from each single frequency network (SFN) transmitter without coverage gaps among adjacent SFN transmitter service areas. No directional receiving antenna is required and receivers simply tune into the stronger local received signal. This is the concept of Cloud Transmission. In LDM system, the upper layer is operating in a traditional SFN mode to provide network-wide coverage. The lower layer is actually operating in a special form of Distributed MIMO or gap-filler mode to provide a targeted local coverage. Only Advanced Television Systems Committee (ATSC) 3.0 Baseline Technologies are used, i.e., there is no need to modify the ATSC 3.0 standard. Giving the upper and lower layers data rate requirements and the SNR thresholds, the lower layer injection level can be optimized for maximizing upper and lower layer performance and coverage.