Propagation path loss will reduce the range of the communication network. 60 GHz bands have this property of more propagation path loss when compared with other low frequency band communication networks. In this case you can try to build a network with small range but more bandwidth (60 GHz bands have more bandwidth) and data rate.

Reduced coverage range will increase the frequency reuse and hence increases the spectral efficiency.

Regards,

Balaji Dhayabaran

I partially agree with Weisi. However, the formalism follows from the stochastic geometry framework and is only valid in the interference limited scenario, i.e., when only SIR is considered. Things are significantly different once SINR is considered with holistic approach. Moreover, the key point that such framework misses is that under frequency reuse, admission control etc. the performance of the cellular network is  indeed a strong function of the deployment density.

Regarding the performance of the 60GHz systems vs. 1 GHz system, they are completely different ball games. At 60 GHz, absorption and attenuation due to rain and water vapours is signifcant. The path-loss function does not follow power-law and is dependent upon building density etc. Thus at 60 GHz, ferquency reuse can be significantly improved. Currently the debate in research and industry is based on the fact that should be transmit within the absorption window, i.e., exploiting the fact that signal will attenuated at higher distances or transmissions can be scheduled outside these windows so as to increase the link distance. It also depends on application and deployment scenario. For instance, in case of backhual longer link distances are more desirable than aggressive frequency reuse.

More propagation loss in a cellular systems means the co-channel interference is reduced, for any given distance between cells, which means you can pack cells closer together (while offering good SINR at the closer range). So sure, all else equal, 1000 base stations in a given area will offer the same spectral efficiency no matter what the carrier frequency. But all else is never equal. At the higher frequencies, you can credibly deploy microcells, for example.

And there's more. At 60 GHz, each RF channel will probably have much wider bandwidth than the 1 GHz channels do. So in addition to a more dense distribution of cells, each cell will also support greater capacity, most likely.

And there's still more. At 60 GHz, it's easier to design highly directional antennas of small size, to permit the sorts of pencil beams being studied for the deployment of massive MIMO, e.g. in 5G cellular. Massive MIMO depends on aiming beams at precise locations in space.

On the other hand, efficiency sometimes means reducing costs for long haul communications, as opposed to cramming the highest possible payload capacity in the least possible spectrum.

definitely the propagation loss occur in various frequency bands eg around 60 Hz so called attenuation bands some due to clouds, so these frequencies can be used for, shorter distance communication

Higher propagation loss, offer lower co-channel interference and also lower coverage area for each base station. For this case, you can do the frequency reuse more and more but it should be noted that small cells for high velocity users force higher number of handoffs and consequently decreasing the QoS. Hence, higher frequencies are introduced for D2D communications or indoor communications.