User's Manual Part 2

Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex
®
(NG2)
7-16
Intro
Overview
Wi-Fi
Ethernet
System
IP/Video
MoCA
RF
Specs
Figure 7-10 Node Stats page (Any node except the unit)
The Node Stats page also includes links to bit-loading graphs which chart the number of bits that
subcarrier frequencies are carrying (per symbol), across the MoCA channel in use. An active network
continuously adjusts the number bits each symbol is expected to carry (that is, adjusts the QAM level),
loading each subcarrier to the maximum amount that probe exchanges have determined is feasible for
reliable transmission. Therefore, a bit-loading graph is essentially a granular view of channel bandwidth.
If the coaxial cable has impairments which cause excessive attenuation, a bit-loading graph should show
large trends of lower bit loading across the channel, causing a degradation of overall bandwidth.
Each tab has two bit-loading graphs, one for transmitting from the unit to the respective node (Tx) and
one for transmitting from that node to the unit (Rx). For the tab representing the unit itself, the graphs
should be blank because transmission to itself is not applicable.
A bit-loading graph presents all available subcarriers on the x-axis and plots the number of bits that each
is carrying on the y-axis (8 bits maximum for 128-QAM, 10 bits for 1024-QAM, see MoCA physical layer
on page 7-36). As a MoCA 1.1 example, the following graph shows an Rx link from Node 7 that is
performing well. All subcarriers are carrying 6 or more bits per symbol:
Preliminary issue - Limited distribution only!