Reducing power consumption has been a priority in the telecommunications industry for years with efforts focused on both devices and base stations. The 3GPP, for instance, has been tackling this issue from the perspective of switching times, or shutting down parts of a network when not in use. While this works great, there is still a lot of wasted energy, and Qualcomm is proposing a complementary approach of optimizing power consumption even when the network is actively transmitting by improving the efficiency of a network’s power amplifier (PA), and in some cases, the spectral efficiency.
This, Gideon Kutz, senior director of technology at Qualcomm, told RCR Wireless News, can lead to a significant reduction in energy consumption without sacrificing signal quality. If you extrapolate that across a network, there can be a very real impact on both an operator’s operating expenses and, at a large enough scale, on environmental sustainability goals articulated by companies and governments the world over.
PAs are a major source for power inefficiency in base stations, since they are normally used with large backoff (i.e. a lot of margin to operate) to avoid non-linear distortions. If, to address this, they are moved to a more power-efficient operating point, by reducing this backoff, the result would be a loss in signal quality. As an alternative, Qualcomm demonstrated a combination of signal processing techniques to improve PA efficiency in existing base station hardware–meaning these solutions can be deployed without a hardware upgrade.
Digital post distortion is one such technique, and according to Kutz, when this method is used, then the PA can move to a more power-efficient operation point without resulting in a reduced signal quality, since the non-linear distortions created by the PA in the base station can be rectified in the mobile station.
“Moreover,” he added, “in many cases the new signal quality is actually better than the baseline, allowing an increase in spectral efficiency.”
The second technique that Qualcomm demonstrated is Super-QAM, in which some of the radio transmission impairments are cancelled in an iterative manner to allow higher order modulation. With this technique, Qualcomm was able to significantly increase the peak data rates.
In fact, Ronen Shaked, principal engineer at Qualcomm, explained in a demonstration how Super-QAM increased peak data rate between 50-60%, which will reduce base station transmission duration, and in turn, reduce power consumption.
These demonstrations are part of Qualcomm’s larger efforts to encourage different vendors and companies in the telecommunications space to develop algorithms that can be applied to a common energy consumption model for base stations. This could create a win-win-win–better network experiences for users, lower opex for operators, and a more sustainable world for everyone.
Watch the RCR Interview: 5G Green Networks here.
For more content, including demos and live interviews, from Qualcomm’s recent Advanced 5G Research Demonstrations for MWC ’21 click here.
