Backhaul For RF Distributed Radio Access Nodes

Abstract

The outset for distributed RF radio access as presented in Chapter 1 included several types of repeaters, classified by their radio interaction with the donor cell, and by the connections (or backhaul, borrowing the term commonly used in digital links) between their donor and remote units. The backhaul thus constitutes part of the repeater system. This chapter presents the linking types that are commonly employed with dedicated conduit repeaters, including the underlying characteristics of the backhaul, and the main considerations for employing a specific type of conduit. 8.1 Analog and Digital Backhauls Repeater backhauls may be classified by the nature of the signals carried over the backhaul; we consider here only RF modulated signals, in contrast to payload data that requires a dedicated modem stack at the remote site (this type of site is termed a remote sector). The RF signals that are communicated between the repeater remote and donor units have the same PN as that of the donor sector, and thus serve to extend the donor sector coverage. 8.1.1 Analog Backhaul The RF signals are transported over the full-duplex backhaul under linear processing operations, including amplification, filtering, heterodyning and linear modulation-demodulation. The noise that is generated along the backhaul chain is modeled as additive white noise, and is a controlled parameter in the design process.