Multi-hop relay topology

A multi-hop relay topology is defined by IEEE 802.16j-2009 to extend a base station’s (BS) coverage area by permitting subscriber stations/Mobile subscribers (SS/MS) to relay traffic by acting as relay stations (RS). Data destined to an SS/MS outside of the BS’s range is relayed through adjacent RSs. An RS can only forward traffic to RSs/SSs within its Security Zone.

Data originating outside of a BS’s coverage area is routed over multiple RSs, increasing the network’s total geographical coverage area, as seen in the diagram below. Multi-hop relay topology typically uses NLOS signal propagation because its purpose is to span large geographic areas containing multiple RF obstacles; however, technically it can operate using LOS propagation as well. The maximum operating range for each node in a multi-hop relay topology is approximately 8 km (5 miles).