Frequency Reuse and System Capacity in Mobile Broadband Systems: Comparison between the 40 and 60 GHz Bands

Abstract

This paper addresses the comparison of characteristics between the bands of40 and 60 GHz, prospectively allocated for Mobile Broadband CommunicationSystems. The key difference between the two bands is the oxygen absorption,which is negligible at 40 GHz, but presents high values at 60 GHz, decreasingfrom 14 dB/km (at 62 GHz) down to approximately 1 dB/km (at 66 GHz). Theimpact of this excess absorption is two-fold: on one hand it reduces thereceived signal power but on the other hand it also reduces the co-channelinterference. These two quantities may not suffer the same amount ofreduction, and hence differences in the reuse pattern may result. The resultsshow that for the regular coverage geometries the difference in the reusepattern obtained in both bands is not relevant, a value of 3 being achieved.Differences however exist in the range of maximum coverage distances valuesat 43.5 GHz being up to 20% larger than at 66 GHz. For irregular urbangeometries the results obtained from specific cellular layouts, show that thereuse pattern is the same for both bands (in the range 5–7)for the the range of coverage distances where the system operationinterference limited (say, for coverage distances less than 124 m).Again, larger coverage lengths can be achieved at 40 GHz, although with ahigher associated reuse pattern.