Transmit and Receive Signal Processing for MIMO Terrestrial Broadcast Systems

Abstract

Multiple-Input Multiple-Output (MIMO) technology in Digital Terrestrial Television (DTT) networks has the potential to increase the spectral efficiency and improve network coverage to cope with the competition of limited spectrum use (e.g., assignment of digital dividend and spectrum demands of mobile broadband), the appearance of new high data rate services (e.g., ultra-high definition TV -UHDTV), and the ubiquity of the content (e.g., fixed, portable, and mobile). It is widely recognised that MIMO can provide multiple benefits such as additional receive power due to array gain, higher resilience against signal outages due to spatial diversity, and higher data rates due to the spatial multiplexing gain of the MIMO channel. These benefits can be achieved without additional transmit power nor additional bandwidth, but normally come at the expense of a higher system complexity at the transmitter and receiver ends. The final system performance gains due to the use of MIMO directly depend on physical characteristics of the propagation environment such as spatial correlation, antenna orientation, and/or power imbalances experienced at the transmit aerials. Additionally, due to complexity constraints and finite-precision arithmetic at the receivers, it is crucial for the overall system performance to carefully design specific signal processing algorithms.This dissertation focuses on transmit and received signal processing for DTT systems using MIMO-BICM (Bit-Interleaved Coded Modulation) without feedback channel to the transmitter from the receiver terminals. At the transmitter side, this thesis presents investigations on MIMO precoding in DTT systems to overcome system degradations due to different channel conditions. At the receiver side, the focus is given on design and evaluation of practical MIMO-BICM receivers based on quantized information and its impact in both the in-chip memory size and system performance. These investigations are carried within the standardization process of DVB-NGH (Digital Video Broadcasting -Next Generation Handheld) the handheld evolution of DVB-T2 (Terrestrial -Second Generation), and ATSC 3.0 (Advanced Television Systems Committee -Third Generation), which incorporate MIMO-BICM as key technology to overcome the Shannon limit of single antenna communications. Nonetheless, v ABSTRACT this dissertation employs a generic approach in the design, analysis and evaluations, hence, the results and ideas can be applied to other wireless broadcast communication systems using MIMO-BICM.The first part of the thesis analyses the performance and structure of MIMO precoders based on rotation matrices for 2×2 MIMO and focus on the case of cross-polar antennas, which is the preferred configuration in DTT systems in the UHF band. Analysis and evaluation with the information-theoretic limits of BICM systems and bit-error-rate simulations including channel coding show the interesting results that the performance of the precoder depends on the selected code-rate. While rotation can provide signific...

Evaluation and Optimization of Multiple-Input Multiple-Output Antenna Schemes for Next-Generation Wireless Broadcasting

“…A conventional topology for DTT comprising a single transmit antenna and a single receive antenna is referred to as SISO. The increasing interest in MIMO systems has given rise to its consideration for terrestrial broadcasting and its performance was evaluated [54] by information-theoretical study and simulations. The utilization of MIMO for broadcasting systems was discussed in the ATSC 3.0 standardization process to expand the transmission capacity, however MIMO broadcasting has not been commercialized mainly due to the absence of a strong market at the present moment.…”

“…For MIMO transmission, the SNR was defined as the ratio of the total transmit power for two polarized signals (antenna #1 and #2) to the AWGN power at each receiver (either antenna #1 or #2) in this thesis. With the definition, the transmitting power of SISO and MIMO is equal, and a fair comparison can be made from the perspective of power consumption efficiency [54]. In this thesis, the required SNR was defined as the SNR to achieve BER =1×10 -4 for ATSC 3.0.…”

“…In the literature multiple definitions are used for SNR or CNR and most MIMO studies assume that the total transmit power is kept constant between MIMO and SISO for fair comparison especially for theoretical analysis [54]. However, since this thesis focuses on the performance comparison between MIMO and SISO in practical deployment scenarios, we decided to use the CNR definition based on the average received power 𝑃 𝑎𝑣𝑒 .…”

“…The new mobile allocation, also known as Second Digital Dividend (DD2), was made in Region 1 in the 700 MHz band. Implementing the DD2 within ITU Region 1 may affect up to eleven more DTT channels (49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60), creating several challenges. The DD2 may be particularly problematic in countries where terrestrial television is the main distribution platform, such as the United Kingdom, France, Spain, Portugal and Italy.…”