Dead zone in North Portland

The entire St Johns neighborhood around Lombard and Buchanan in North Portland is an absolute dead zone for cell coverage. My neighbors say it has been this way for a while.  There are NO bars of coverage in my own driveway.  WiFi is not an acceptable solution because as soon as there is a power or internet outage, there is no cellphone. This is extremely dangerous - what if someone is injured during a power outage, or while on the street not covered by WiFi? I would like to know what is being done about this ASAP.  Thanks.