That's not really possible. iPhones require an iCloud account which even if not directly linked to you, serves as a pool of information that Apple can gather about you and work out your identity from. The second you switch on your phone, it connects to several cell towers and enables your position to be triangulated. As you move around between work, home, the shops, it's constantly informing the providers of your location. Even if you switch SIMs regularly, your device's IMSI number is static and serves as a unique fingerprint. Conveniently, spoofing IMSI numbers is illegal. Guess why.

Theoretically it might be possible to combat cell tower triangulation by having the modem only respond to one tower at a time and insert artificial latency to make it harder to work out your distance. But, another convenient fact: cell modems are all closed source, proprietary black boxes. They also have DMA (Direct Memory Access) to your phone.

Perhaps I should be wearing a tinfoil hat but these don't seem like coincidences to me. They seem like intentional measures to weaponise a tool in our everyday lives.