| My opinion you will see DOCSIS 3.0 in area where FTTH is available and offering higher speeds like 20/5 and up, but it will take telco's 10+ years to get all their FTTH plant ready.
Cable companies can offer higher speeds if they want without upgrading to DOCSIS 3.0. They would need to change the return combining to reduce the number of users going to a uBr port and reduce the number of users on the forward docsis qam. It actually is a very simple process to do this. I have been doing this type of node reduction for the past 1 year.
A lot of people think as it sits today that they are sharing only with people in their node, but in some/most cases you could be sharing with 2-4 nodes. I haven't really seen more than 4 nodes combined since 1998, but I guess some company could still be like that.
Keep in mind this work is all in the headend, no need to visit nodes to do reduction. We have now just started doing 1:1 combining and in heavy modem active nodes we have split them in half (which does require a node upgrade in the field).
About 40% of our nodes are 1:1 as it sits today using 3.2mhz QPSK modulation for upstream and 256QAM downstream. We are now migrating over to 3.2mhz 16QAM for an upstream which will enable us to offer higher data rate on the upstream.
Here is some info on DOCSIS
By Ron Hranac, Senior Technology Editor
DOCSIS 1.x
DOCSIS 1.0 provided the cable industry with standards-based interoperability, which means certified cable modems from multiple vendors work with qualified cable modem termination systems (CMTSs) from multiple vendors. DOCSIS 1.1 added a number of features, including quality of service (QoS), more robust scheduling, packet classification and other enhancements that facilitate voice services. Upstream transmission robustness was improved with the introduction of eight-tap adaptive equalization in DOCSIS 1.1 modems.
DOCSIS 1.0 and 1.1, collectively known as DOCSIS 1.x, support two downstream modulation formats: 64-QAM (quadrature amplitude modulation) and 256-QAM. These two modulation formats provide raw data rates of 30.34 and 42.88 Mbps respectively in a 6 MHz wide downstream channel. DOCSIS 1.x accommodates several upstream data rates, ranging from a low of 320 kbps to a high of 10.24 Mbps. It also supports two upstream modulation formats—quadrature phase shift keying (QPSK) and 16-QAM—as well as five upstream RF channel bandwidths.
DOCSIS 2.0
DOCSIS 2.0 brought the cable industry higher upstream per-channel data throughput, increasing the maximum to as much as 30.72 Mbps. Downstream functionality remains largely unchanged, retaining 64- and 256-QAM capability. DOCSIS 2.0 defines the use of 64-QAM in the upstream—plus 8-QAM, 32-QAM and the modulation formats from DOCSIS 1.x—and optionally supports 128-QAM trellis coded modulation (TCM) for synchronous code division multiple access (S-CDMA) channels.
The increased upstream per-channel data throughput available with DOCSIS 2.0 technology is accomplished using higher orders of modulation and increased RF channel bandwidth. Higher orders of modulation than QPSK and 16-QAM require substantially more robust data transmission. This is especially true in the often hostile reverse path RF spectrum used in most cable networks. To facilitate more robust upstream data transmission, DOCSIS 2.0 introduced a set of features called advanced PHY |
