First of all, your body would likely screw up the interference patterns enough that it wouldn't be a "ball of energy" in the center of the person - it would likely mostly diffusely heat them.
Second, the amount of power to burn a person is many orders of magnitude higher than needed to receive a signal. The transmitters would have to be extraordinarily powerful. I can only see this happening if they plan on making a wireless power transmission service.
Also, a 1cm ball is extremely optimistic, given that LTE frequences have several cm wavelengths. It would also require an enormous number of pCell transmitters to concentrate their transmission into such an area. For communications though, even concentrating into a 20m ball would be a huge improvement over existing technology, so I don't know if there is incentive to place more antennas than required for that.
Second, the amount of power to burn a person is many orders of magnitude higher than needed to receive a signal. The transmitters would have to be extraordinarily powerful. I can only see this happening if they plan on making a wireless power transmission service.
Also, a 1cm ball is extremely optimistic, given that LTE frequences have several cm wavelengths. It would also require an enormous number of pCell transmitters to concentrate their transmission into such an area. For communications though, even concentrating into a 20m ball would be a huge improvement over existing technology, so I don't know if there is incentive to place more antennas than required for that.