Hybrid-Mux Signal Structure and Resource Allocation for In-Band Distribution Link and ITND Transmission in SFN Environment

Abstract

This paper investigates the multiplexing and resource allocation to improve the spectrum efficiency and reduce demultiplexing complexity and latency in the wireless in-band distribution link (IDL) and inter-tower networks and datacasting (ITND) for terrestrial broadcasting systems. A novel Hybrid-Mux technology is proposed, which combines orthogonal multiplexing (TDM/FDM), non-orthogonal multiplexing (NOM, or LDM), and hierarchical modulation (HM) with the non-uniform constellation (NUC). Hybrid-Mux technology can achieve high spectrum efficiency, low complexity, and low latency to provide versatile services of mobile/fixed broadcast services, inter-tower communication networks and datacasting, as well as the in-band distribution link to support SFN operation. Two Hybrid-Mux signal structures with 2-layer and 3-layer power-based non-orthogonal multiplexing of different broadcast and network data services are introduced. The throughput optimization of each Hybrid-Mux structure is formulated and resolved under the constraint of ITND and IDL data capacity, SNR requirement, and optimized NUC HM. Simulation results show that, by properly implementing resource allocation and constellation design, the proposed 3-layer Hybrid-Mux structures can achieve higher capacity than the simple 2-layer Hybrid-Mux structure, while the demodulation and demultiplexing complexity is not much increased. A 2-tier ITND service is proposed. It consists of a robust control and datacasting (ITCD) tier and a high data rate intertower networking (ITCN) link. This design can increase the total aggregated system data rate substantively. MIMO structures supporting ITND and IDL transmission are also proposed to further improve the spectrum efficiency.