5
Baseband Modulation
5.1 Introduction
The choice of baseband modulation scheme for 60 GHz wireless depends on many factors such as the channel characteristics, deployment scenarios, antenna configurations, applications, spectrum efficiency and circuit limitations.1 In general, three types of modulations are suitable candidates for 60 GHz communications, namely minimum shift keying (MSK), single carrier (SC) block transmissions and multi-carrier (MC) transmissions. A SC would be used to carry the MSK modulated information symbols as well. In this sense, MSK is itself a SC modulation scheme. We note that the term “single carrier” modulation in this chapter mainly refers to the SC block transmissions with general non-constant-envelope constellations, for example M-QAM. For MC transmissions, we focus on orthogonal frequency division multiplexing (OFDM) in this book.
MSK is a promising modulation scheme within the family of constant-envelope modulation. Its constant modulus with no peak-to-average power ratio (PAPR) enables high-efficiency operation of transmit power amplifiers (PAs) as described in Section 3.2. This makes MSK a very appealing modulation choice for 60 GHz. MSK also enjoys a high receive power efficiency in terms of power used to receive each bit. However, MSK suffers from relatively low throughput, especially in high signal-to-noise-ratio (SNR) regions, which limits its usage to the lower data rate range of multi-gigabit transmissions. ...
