ADI White Paper: Solutions for Designing and Building a Power Efficient O-RAN solution

When the wireless revolution began some 30 years ago, there were only a handful of bands, mostly confined below 900 MHz and typically 1 or 2 bands per country. Today, driven by exponential growth, there are 76 LTE and 5G bands in FR1 alone. This is pushing frequencies higher up to find available spectrum. The recently completed C-band auction in the US (at 3700-3980MHz) highlights this. Now, as the industry pivots from buying spectrum to building the network, they will find that C-band is very different from previous deployments from an RF perspective. In particular, some radio architectures in C-band, when co-locating with legacy radios, could lead to a site management nightmare due to interference.

We’ve all seen the increasingly crowded macro towers and marveled at the weight and wind-load that the towers must be supporting. Initial deployments of C-band will most likely re-use these sites which means that C-band radios will be co-located with LTE and GSM devices. Consider that at the top of the tower, one radio may be transmitting at 100W or more while another radio just a meter (or less!) away is receiving n13, n14 n5 n2, n70 n4 n77 f s /2 3f s /2 a signal at less than 100 nW or about 10 billion times lower power. This has been the case previously, but a new twist to the mix is the increased potential for aliases, or signal interference, because of C-band’s higher frequencies.