Wireless Architectures

The following section will provide a simple overview of wireless concepts and nomenclature to help the reader understand how WiMAX works and will assist the reader in com-municating with the WiMAX industry.


Wireless architecture: point-to-point and point-to-multipoint

There are two scenarios for a wireless deployment: point-to-point and point-to-multipoint.



Figure 7: Point-to point and point-to-multipoint configurations

Point-to-point (P2P)

Point to point is used where there are two points of interest: one sender and one receiver. This is also a scenario for backhaul or the transport from the data source (data center, co-lo facility, fiber POP, Central Office, etc) to the subscriber or for a point for distribution using point to multipoint architecture. Backhaul radios comprise an industry of their own within the wireless industry. As the architecture calls for a highly focused beam between two points range and throughput of point-to point radios will be higher than that of point-to-multipoint products.

Point-to-Multipoint (PMP)

As seen in the figure above, point-to-multipoint is synonymous with distribution. One base station can service hundreds of dissimilar subscribers in terms of bandwidth and services offered.


Line of sight (LOS) or Non-line of sight (NLOS)?



Figure 8: The difference between line of sight and non-line of sight

Earlier wireless technologies (LMDS, MMDS for example) were unsuccessful in the mass market as they could not deliver services in non-line-of-sight scenarios. This limited the number of subscribers they could reach and, given the high cost of base stations and CPE, those business plans failed. WiMAX functions best in line of sight situations and, unlike those earlier technologies, offers acceptable range and throughput to subscribers who are not line of sight to the base station. Buildings between the base station and the subscriber diminish the range and throughput, but in an urban environment, the signal will still be strong enough to deliver adequate service. Given WiMAX's ability to deliver services non-line-of-sight, the WiMAX service provider can reach many customers in high-rise office buildings to achieve a low cost per subscriber because so many subscribers can be reached from one base station.