Chapter 5 discusses the implementation of ISO 18000-63 downlink and uplink communication chains and offers practical code developed in MATLAB for evaluating the signal processing of the full RFID communication chain. The code provided is suitable for custom projects.

The most basic and most widely used form of mapping binary information to a physical transmit signal and back is digital pulse-amplitude modulation (PAM). As the name suggests, here the information is carried in the (complex-valued) amplitude of a basic pulse. We deal with real-valued and complex-valued amplitude coefficients in a unified manner. Thus, all kinds of baseband (amplitude-shift keying (ASK)) and carrier-modulated (quadrature-amplitude modulation (QAM) and phase-shift keying (PSK)) signal formats are included in the concept of PAM. PAM is the simplest form of digital modulation but establishes the basis for enhanced variants discussed in subsequent chapters. In this chapter, the focus is on modulation and demodulation operations. As, in a first approach, no channel coding is considered, modulation reduces to a symbol-by-symbol mapping of blocks of binary source symbols to signal points and detection at the receiver side can also be performed symbol by symbol. Strategies for optimum signal detection and conditions for continuous transmission of sequences of symbols without intersymbol interference (ISI) over non-dispersive channels are precisely developed.