ADVANCED INTERFERENCE REJECTION
In addition to D2D capabilities and massive volumes of memory, future mobile devices may also
have varying form factors. In some instances, the Figure 4. Cell data rate comparison for a fixed access application of massive MIMO. An array of 2048, 4096, or 8192 antennas, utilizing 50 MHz and radiating a total of 120 W, serves 1000 users randomly located in a cell of radius 6
km. Results are given in terms of gain (%) w.r.t. the MIMO 4×4 baseline.50th percentile 1000 Percentage
0
2000
3000
4000
5000
6000
7000
8000
2048 antennas
4096 antennas
8192 antennas
5th percentile 4 Low-latency local communications are discussed also in the next section. However, while the focus in this section is on use cases requiring local human interaction (e.g., video gaming or augmented reality), the focus in the next section is on use cases requiring local interaction between objects (e.g., vehicles).
BOCCARDI_LAYOUT_Layout 1/30/14 12:57 PM Page 78 IEEE Communications Magazine • February 2014 79
devices might accommodate several antennas with the consequent opportunity for active interference rejection therein, along with beam forming and spatial multiplexing. A joint design of transmitter and receiver processing, and proper control and pilot signals, are critical to allow advanced interference rejection. As an example, in Fig. 5 we show the gains obtained by incorporating the effects of nonlinear, and intra and inter-cluster interference awareness into devices with one, two, and four antennas. While this section has mainly focused on analyzing
the implications of smarter devices at a component level, in the previous section we discussed
the impact at the radio access network architecture level. We regard smarter devices as having all the characteristic of a disruptive technology for 5G, and therefore we encourage researchers to further explore this direction.