Which cell phone, laptop, modem or router you use are of great importance for how your experience of the coverage and speed will turn out. In places where you lack coverage but you have access to wifi, you can use your cell phone as usual if you have a subscription that supports 4G.
It is possible to improve the opportunities to call and surf by using a so called handsfree (a cord with headphones and microphone) or an extern antenna. The possibility can also be improved further if the cell phone is laying on an open area instead of being held by hand or lying in a pocket or in a bag.
The normal speed is specified with an interval, and refers to an average for the entire cellular network and therefore does not necessarily reflect the experience of the individual user. The normal speed does not constitute a guarantee for the speed the individual user actually achieves at every occasion, it is an estimation of what the user normally can expect.