Massive MIMO (Multiple Input Multiple Output) addresses exactly this challenge.
MIMO is a technology used in 4G / 5G Wireless Broadband. It provides multiple communication paths between the transmitters and the receivers. This is made possible by deploying multiple antennas on the transmitting as well as receiving side. Whereas it is comparatively easier to deploy multiple antennas on the cell towers, it is much more challenging to deploy multiple antennas on the smartphones.
Welcome Millimeter Wave carrier frequencies! If we push up the carrier frequency to, let us say, 60 GHz, the required minimum separation between multiple antennas is pushed down to only 2.5 mm. Well, that implies that we could easily fabricate 16 antenna elements within a square of 1 cm.
With Massive MIMO, we have the ability to squeeze an array of 16 antennas or more, within the form factor of a smartphone. In fact, the next generation Wireless Broadband standard called WiGig (IEEE 802.11ad) aims to achieve a robust data rate of upto 7 Gbps by using 60 GHz unlicensed carrier and Massive MIMO techniques.