Most of the power consumption of the active CATV network equipment occurs in the amplifier module. In this application and also in our ‘submission video’, the amplifier module refers to a typical hybrid component in output stage of an optical node or amplifier station. Any reduction in the power consumption of the amplifier module can create significant savings. To make energy-efficiency possible, most of the amplifier modules have got a power saving feature, which enables reducing the power consumption of the amplifier module by adjusting bias current.
Teleste’s core idea for the topic is based on the fact that although the CATV network equipment is designed and operated to fulfil their specifications at the full 1.2 GHz load, the actual capacity used in the network is seldom that heavy. When the maximum capacity is not in use, the amplifier module can be operated with lower bias current, which then results in lower power consumption. It is also extremely important that the quality of end-user experience stays intact. Therefore, we have been carrying out extensive studies to validate our solution. Today, the most, if not all, of the 1.2 GHz CATV network devices are using lots of extra power, since practically no capacity is used above 1.0 GHz. We believe that, in the future, the full capacity up to the 1.2 GHz will not be totally exploited, which creates opportunity for prolonged power saving.
There are several ways to implement the power saving feature to CATV network equipment, all based on the adjustment of bias current in the amplifier module. Below, we present three novel methods to do that:
1. Remotely adjusted performance levels (in reference to submission video): The CATV network devices (i.e., optical nodes and amplifier stations), can have two or more pre-defined power save states. They can be remotely controlled via a simple extension of the current unidirectional communication method, which is used to remotely command ingress switches in the amplifier station (Refers to Remote Ingress Switch (RIS) in the Liberty Global documentsInitially RIS was developed to enable cost efficient unidirectional remote management of ingress switches in the amplifier stations. However, the RIS software can be further enhanced with minor modifications to support also remote management of the power save mode in the amplifier module. For example, utilizing the RIS allows changing the power save mode within one hub area just by clicking a button at the back office. The power save modes can be set according to the capacity used.
The method is based on purpose-built hardware and software implementations in optical nodes and amplifier stations. The hardware needs to have inexpensive RIS receiver and ability to adjust bias current of the amplifier module. The back office requires a ‘master-modem like’ function, which is used to remotely command equipment in the field. The latter can be provided as a service, due to seldom occurring changes in the downstream bandwidth.
2. Autonomous performance adjustment (in reference to submission video): To measure total downstream RF power and determine the capacity that is in use in a network, the CATV network equipment can be harnessed with built-in RF power measuring function. The amplifier module’s power consumption is then adjusted based on these measurements.
The method is a ‘stand-alone’ automatic function and hence no remote access is needed. It is based on purpose built hardware and software implementation in optical nodes and amplifier stations. The hardware needs to have RF power measuring capability and the ability to adjust bias current of the amplifier module.
3. Load-based performance adjustment (in reference to submission video): Distributed Access Architecture (DAA) node is aware of the capacity used in the network because it generates digital TV and DOCSIS data content by modulating it into RF signal. This capacity information can be used to adjust the amplifier module’s power consumption to meet the requirements of the capacity used. The method is a ‘stand-alone’ automatic function and hence no remote access is needed. In the case of RF overlay deployment, an additional tuner module to measure broadcast TV part should be considered. We have such a tuner module available off-the-shelf. It should be noted that this feature do not require complex (2nd generation) Digital Pre-distortion (DPD) implementation.
The method requires only software modification, in most of the cases, as all of our RPD node implementations already support the bias current adjustment function. A tuner hardware module may be needed subject to the RF overlay deployment.