WiMAX Forum Certified
Ahmed Ebraheem, Managing Director, MADA
"After a thorough evaluation of several wireless broadband solutions providers, we came to the conclusion that Aperto Networks had the most advanced and the most stable platform. We were especially pleased with the Quality of Service and the routing and advanced networking features built into Aperto's platform. Its flexible architecture ensures a future proof evolution as we implement new subscriber services in the coming months and years."



Cell reuse factor of 3, sector reuse pattern of 2

Aperto® recommends using a cell frequency reuse factor of 3 as a good compromise between overall efficiency and maximum burst rate available in any given sector. With such a reuse pattern, a total of six channels are required to cover a large network of cells. If more spectrum is available additional channels can then be overlaid to these channels for additional capacity.

For a broadband wireless system deployed in a cell grid, the C/I ratio of the subscriber unit's varies as a function of the relative distances to the serving sector's base station transmitter and to the interfering base station transmitters. Geometric models show that the minimum C/I ratio in any given sector is a function of the sector and cell reuse factor.

Cell Reuse Factor

Minimum C/I

Possible Modulation


13 dB



18 dB

QPSK and 16 QAM


21 dB

QPSK and 16 QAM

Table: Minimum C/I ratios for different cell reuse factors
Note that higher cell reuse factors would be needed to enable higher order modulations such as 64 QAM (for example a cell reuse factor of at least 7, requiring a total of 14 RF channels would be needed in this case). Overall such a system would therefore make a less efficient use of the spectrum in a multi-cell network. Some of the other vendors in the BWA space support 64 QAM modulation and claim higher spectral efficiency. However this analysis shows that this claim is misleading, since when intercell co-channel interference is taken into account, then the resulting spectral efficiency is lowered.