Mobile phones still rely on LoS also You will be amazed how many cell sites are around, not just the towers you see. Most big buildings have Mobile anntenas on the roof these days
Just about every form of radio communication needs LoS.
Mobile phone network will also take advantage of mutlitpathing as will WLAN but the mobile phone network is better at this due to the fact that both the handset and the cell site transmitter use power than is allowed in WLAN
The more transmit power the more useable the signal will be after it reflects off an object.
Think of a RADAR it uses very high frequency and very high power often in the mega watts It reflects very well, otherwise it would not be useful as a RADAR
Even in case of cellular network we need LoS...All of us notice that the cell towers ae erected on roof tops of high rised buildings...Also, the number of cell towers are comparatively high so that the range of each tower is within the reach of another tower.
Secondly, the signal strength in mobile network is very high enabling the signal to pass thru certain objects..