Broadband Cable Access Networks

Chapter 8. Upstream Issues

8.1. Introduction

This chapter covers a number of topics of interest to those using return plant or needing to understand the issues involved in the operation of return plant. Return, or upstream, signal levels must be managed differently from downstream signal levels, and this topic is covered in some depth. Return laser characteristics are covered, along with methods used to determine the proper level at which to operate return lasers. Finally, noise on the return path is dealt with. Several methods of analyzing the problem are presented, as are some alternative countermeasures.

Limited two-way cable plant has been built since the mid to late 1970s. As early as 1972, the FCC required that plant be built to be “two-way ...